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Bone marrow is a dynamic organ composed of stem cells that constantly receive signals from stromal cells and other hematopoietic cells in the niches of the bone marrow to maintain hematopoiesis and generate immune cells. Perturbation of the bone marrow microenvironment by infection and inflammation affects hematopoiesis and may affect immune cell development. Little is known about the effect of malaria on the bone marrow stromal cells that govern the hematopoietic stem cell (HSC) niche. In this study, we demonstrate that the mesenchymal stromal CXCL12-abundant reticular (CAR) cell population is reduced during acute malaria infection. The reduction of CXCL12 and interleukin-7 signals in the bone marrow impairs the lymphopoietic niche, leading to the depletion of common lymphoid progenitors, B cell progenitors, and mature B cells, including plasma cells in the bone marrow. We found that interferon-γ (IFNγ) is responsible for the upregulation of Sca1 on CAR cells, yet the decline in CAR cell and B cell populations in the bone marrow is IFNγ-independent. In contrast to the decline in B cell populations, HSCs and multipotent progenitors increased with the expansion of myelopoiesis and erythropoiesis, indicating a bias in the differentiation of multipotent progenitors during malaria infection. These findings suggest that malaria may affect host immunity by modulating the bone marrow niche. [ABSTRACT FROM AUTHOR]

Aims: TP53 alterations have a significant prognostic effect in myeloid neoplasms. Our objective was to investigate the TP53 gene mutation status, p53 protein expression and their relationship in dysplasia‐related myeloid neoplasms with varying levels of myeloblast counts. Methods and results: A total of 76 bone marrow biopsy samples with different blast counts were analysed. Total and strong (3+) p53 expression was determined. Dual immunohistochemical staining was performed to determine the cell population associated with p53 expression. NGS analysis was performed using the Accel‐Amplicon Comprehensive TP53 panel. Both p53 expression and TP53 VAF showed a significant correlation with the myeloblast ratio (P < 0.0001); however, p53 expression was also present in other cell lineages. The VAF value exhibited a significant correlation with p53 expression. A high specificity (0.9800) was observed for TP53 mutation using the ≥ 10% strong (3+) p53 cut‐off value, although the sensitivity (0.4231) was low. Conclusions: Strong (3+) p53 expression using a ≥ 10% cut‐off value accurately predicts TP53 mutation but does not reveal the allelic state. The p53 expression is significantly influenced by myeloblast count, and histological interpretation should consider the presence of intermixed non‐neoplastic marrow cells with varying physiological p53 expression. [ABSTRACT FROM AUTHOR]

Background: Mechanical stimulation (MS) significantly increases the release of adenine and uracil nucleotides from bone marrow-derived mesenchymal stem cells (BM-MSCs) undergoing osteogenic differentiation. Released nucleotides acting via ionotropic P2X7 and metabotropic P2Y6 purinoceptors sensitive to ATP and UDP, respectively, control the osteogenic commitment of BM-MSCs and, thus, bone growth and remodelling. Yet, this mechanism is impaired in post-menopausal (Pm)-derived BM-MSCs, mostly because NTPDase3 overexpression decreases the extracellular accumulation of nucleotides below the levels required to activate plasma membrane-bound P2 purinoceptors. This prompted us to investigate whether in vitro MS of BM-MSCs from Pm women could rehabilitate their osteogenic commitment and whether xenotransplantation of MS purinome-primed Pm cells promote repair of critical bone defects in an in vivo animal model. Methods: BM-MSCs were harvested from the neck of femora of Pm women (70 ± 3 years old) undergoing total hip replacement. The cells grew, for 35 days, in an osteogenic-inducing medium either submitted (SS) or not (CTR) to MS (90 r.p.m. for 30 min) twice a week. Increases in alkaline phosphatase activity and in the amount of osteogenic transcription factors, osterix and osteopontin, denoted osteogenic cells differentiation, while bone nodules formation was ascertain by the alizarin red-staining assay. The luciferin-luciferase bioluminescence assay was used to quantify extracellular ATP. The kinetics of the extracellular ATP (100 µM) and UDP (100 µM) catabolism was assessed by HPLC. The density of P2Y6 and P2X7 purinoceptors in the cells was assessed by immunofluorescence confocal microscopy. MS-stimulated BM-MSCs from Pm women were xenotransplanted into critical bone defects drilled in the great trochanter of femora of one-year female Wistar rats; bone repair was assessed by histological analysis 10 days after xenotransplantation. Results: MS-stimulated Pm BM-MSCs in culture (i) release 1.6-fold higher ATP amounts, (ii) overexpress P2X7 and P2Y6 purinoceptors, (iii) exhibit higher alkaline phosphatase activity and overexpress the osteogenic transcription factors, osterix and osteopontin, and (iv) form larger bone nodules, than CTR cells. Selective blockage of P2X7 and P2Y6 purinoceptors with A438079 (3 µM) and MRS 2578 (0.1 µM), respectively, prevented the osteogenic commitment of cultured Pm BM-MSCs. Xenotransplanted MS purinome-primed Pm BM-MSCs accelerated the repair of critical bone defects in the in vivo rat model. Conclusions: Data suggest that in vitro MS restores the purinergic cell-to-cell communication fostering the osteogenic differentiation and osteointegration of BM-MSCs from Pm women, a strategy that may be used in bone regeneration and repair tactics. [ABSTRACT FROM AUTHOR]

This article discusses a study on a rare and aggressive blood cancer called blastic plasmacytoid dendritic cell neoplasm (BPDCN). The study focuses on a gene called IKZF1, which is important for blood cell development. The researchers identified a novel rearrangement of the IKZF1 gene in a BPDCN patient and investigated its effects on blood stem cells and plasmacytoid dendritic cells. They found that the rearrangement influenced the function and differentiation of these cells. The study provides insights into the underlying mechanisms of BPDCN and potential therapeutic targets. However, further research is needed to fully understand the role of IKZF1 in the disease. [Extracted from the article]

Many microRNAs (miRNAs) are expressed with high spatiotemporal specificity during organismal development, with some being limited to rare cell types, often embedded in complex tissues. Yet, most miRNA profiling efforts remain at the tissue and organ levels. To overcome challenges in accessing the microRNomes from tissue-embedded cells, we had previously developed mime-seq (miRNome by methylation-dependent sequencing), a technique in which cell-specific miRNA methylation in C. elegans and Drosophila enabled chemo-selective sequencing without the need for cell sorting or biochemical purification. Here, we present mime-seq 2.0 for profiling miRNAs from specific mouse cell types. We engineered a chimeric RNA methyltransferase that is tethered to Argonaute protein and efficiently methylates miRNAs at their 3′-terminal 2′-OH in mouse and human cell lines. We also generated a transgenic mouse for conditional expression of this methyltransferase, which can be used to direct methylation of miRNAs in a cell type of choice. We validated the use of this mouse model by profiling miRNAs from B cells and bone marrow plasma cells. Synopsis: Mime-seq 2.0 allows profiling of miRNAs from complex tissues and rare cell populations in the mouse. Cell-specific methylation of miRNAs by the chimeric RNA methyltransferase HENMT1ΔC-T6B enables chemo-selective enrichment by high-throughout sequencing. At-HEN1 efficiently methylates C. elegans and D. melanogaste r miRNAs in vivo, but not in mammalian cells. An engineered HENMT1ΔC-T6B chimera methylates miRNAs in vitro in mammalian cell culture and in vivo in mice. Mime-seq 2.0 combines a simple workflow with high sensitivity to enrich miRNAs even from rare cell populations. A new method based on the expression of a chimeric methyltransferase enables the sequencing of small RNAs from specific cell types in mice. [ABSTRACT FROM AUTHOR]

Bone resorption is driven through osteoclast differentiation by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-Β ligand (RANKL). We noted that a disintegrin and metalloproteinase (ADAM) 10 and ADAM17 are downregulated at the expression level during osteoclast differentiation of the murine monocytic cell line RAW264.7 in response to RANKL. Both proteinases are well known to shed a variety of single-pass transmembrane molecules from the cell surface. We further showed that inhibitors of ADAM10 or ADAM17 promote osteoclastic differentiation and furthermore enhance the surface expression of receptors for RANKL and M-CSF on RAW264.7 cells. Using murine bone marrow-derived monocytic cells (BMDMCs), we demonstrated that a genetic deficiency of ADAM17 or its required regulator iRhom2 leads to increased osteoclast development in response to M-CSF and RANKL stimulation. Moreover, ADAM17-deficient osteoclast precursor cells express increased levels of the receptors for RANKL and M-CSF. Thus, ADAM17 negatively regulates osteoclast differentiation, most likely through shedding of these receptors. To assess the time-dependent contribution of ADAM10, we blocked this proteinase by adding a specific inhibitor on day 0 of BMDMC stimulation with M-CSF or on day 7 of subsequent stimulation with RANKL. Only ADAM10 inhibition beginning on day 7 increased the size of developing osteoclasts indicating that ADAM10 suppresses osteoclast differentiation at a later stage. Finally, we could confirm our findings in human peripheral blood mononuclear cells (PBMCs). Thus, downregulation of either ADAM10 or ADAM17 during osteoclast differentiation may represent a novel regulatory mechanism to enhance their differentiation process. Enhanced bone resorption is a critical issue in osteoporosis and is driven through osteoclast differentiation by specific osteogenic mediators. The present study demonstrated that the metalloproteinases ADAM17 and ADAM10 critically suppress osteoclast development. This was observed for a murine cell line, for isolated murine bone marrow cells and for human blood cells by either preferential inhibition of the proteinases or by gene knockout. As a possible mechanism, we studied the surface expression of critical receptors for osteogenic mediators on developing osteoclasts. Our findings revealed that the suppressive effects of ADAM17 and ADAM10 on osteoclastogenesis can be explained in part by the proteolytic cleavage of surface receptors by ADAM10 and ADAM17, which reduces the sensitivity of these cells to osteogenic mediators. We also observed that osteoclast differentiation was associated with the downregulation of ADAM10 and ADAM17, which reduced their suppressive effects. We therefore propose that this downregulation serves as a feedback loop for enhancing osteoclast development. [ABSTRACT FROM AUTHOR]

Background: Neutrophils play a crucial role in inflammation and in the increased thrombotic risk in myeloproliferative neoplasms (MPNs). We have investigated how neutrophil-specific expression of JAK2-V617F or CALRdel re-programs the functions of neutrophils. Methods: Ly6G-Cre JAK2-V617F and Ly6G-Cre CALRdel mice were generated. MPN parameters as blood counts, splenomegaly and bone marrow histology were compared to wild-type mice. Megakaryocyte differentiation was investigated using lineage-negative bone marrow cells upon in vitro incubation with TPO/IL-1β. Cytokine concentrations in serum of mice were determined by Mouse Cytokine Array. IL-1α expression in various hematopoietic cell populations was determined by intracellular FACS analysis. RNA-seq to analyse gene expression of inflammatory cytokines was performed in isolated neutrophils from JAK2-V617F and CALR-mutated mice and patients. Bioenergetics of neutrophils were recorded on a Seahorse extracellular flux analyzer. Cell motility of neutrophils was monitored in vitro (time lapse microscopy), and in vivo (two-photon microscopy) upon creating an inflammatory environment. Cell adhesion to integrins, E-selectin and P-selection was investigated in-vitro. Statistical analysis was carried out using GraphPad Prism. Data are shown as mean ± SEM. Unpaired, two-tailed t-tests were applied. Results: Strikingly, neutrophil-specific expression of JAK2-V617F, but not CALRdel, was sufficient to induce pro-inflammatory cytokines including IL-1 in serum of mice. RNA-seq analysis in neutrophils from JAK2-V617F mice and patients revealed a distinct inflammatory chemokine signature which was not expressed in CALR-mutant neutrophils. In addition, IL-1 response genes were significantly enriched in neutrophils of JAK2-V617F patients as compared to CALR-mutant patients. Thus, JAK2-V617F positive neutrophils, but not CALR-mutant neutrophils, are pathogenic drivers of inflammation in MPN. In line with this, expression of JAK2-V617F or CALRdel elicited a significant difference in the metabolic phenotype of neutrophils, suggesting a stronger inflammatory activity of JAK2-V617F cells. Furthermore, JAK2-V617F, but not CALRdel, induced a VLA4 integrin-mediated adhesive phenotype in neutrophils. This resulted in reduced neutrophil migration in vitro and in an inflamed vessel. This mechanism may contribute to the increased thrombotic risk of JAK2-V617F patients compared to CALR-mutant individuals. Conclusions: Taken together, our findings highlight genotype-specific differences in MPN-neutrophils that have implications for the differential pathophysiology of JAK2-V617F versus CALR-mutant disease. [ABSTRACT FROM AUTHOR]

Macrophages are phagocytic innate immune cells capable of phenotypical switching in response to the local microenvironment. Studies often use either primary macrophages or immortalized cell lines for hypothesis testing, therapeutic assessment, and biomaterial evaluation without carefully considering the potential effects of cell source and tissue of origin, which strongly influence macrophage response. Surprisingly, limited information is available about how, under similar stimuli, immortalized cell lines and primary cells respond in both phenotypical and functional changes. To address this need, in this work, we cultured immortalized macrophage cell lines derived from different origins (i.e., blood, lung, peritoneal) to understand and compare macrophage phenotypical responses, including polarization and plasticity, morphological changes, and phagocytic functionalities, as well as compared primary macrophages extracted from peritoneal and bone marrow to their immortalized cell line counterparts. We found significant differences in baseline expression of different markers (e.g., CD86, MHCII, CD206, and EGR2) amongst different cell lines, which further influence both polarization and repolarization of the cells, in addition to their phagocytic functionality. Additionally, we observed that, while RAW 264.7 cells behave similarly to the primary bone marrow-derived macrophages, there are noticeable phenotypical and functional differences in cell line (IC-21) and primary peritoneal macrophages, highlighting tissue-specific differences in macrophage response amongst cell lines and primary cells. Moving to three-dimensional (3D) culture in well-defined biomaterials, blood-derived primary and cell line macrophages were encapsulated within hydrogel-based synthetic extracellular matrices and their polarization profiles and cell morphologies were compared. Macrophages exhibited less pronounced polarization during 3D culture in these compliant, soft materials compared to two-dimensional (2D) culture on rigid, tissue culture plastic plates. Overall, our findings highlight origin-specific differences in macrophage response, and therefore, careful considerations must be made to identify the appropriate cell source for the application of interest. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is fatal in the majority of adults. Identification of new therapeutic targets and their pharmacologic modulators are needed to improve outcomes. Previous studies had shown that immunization of rabbits with normal peripheral WBCs that had been incubated with fluorodinitrobenzene elicited high titer antibodies that bound to a spectrum of human leukemias. We report that proteomic analyses of immunoaffinity-purified lysates of primary AML cells showed enrichment of scaffolding protein IQGAP1. Immunohistochemistry and gene-expression analyses confirmed IQGAP1 mRNA overexpression in various cytogenetic subtypes of primary human AML compared to normal hematopoietic cells. shRNA knockdown of IQGAP1 blocked proliferation and clonogenicity of human leukemia cell-lines. To develop small molecules targeting IQGAP1 we performed in-silico screening of 212,966 compounds, selected 4 hits targeting the IQGAP1-GRD domain, and conducted SAR of the 'fittest hit' to identify UR778Br, a prototypical agent targeting IQGAP1. UR778Br inhibited proliferation, induced apoptosis, resulted in G2/M arrest, and inhibited colony formation by leukemia cell-lines and primary-AML while sparing normal marrow cells. UR778Br exhibited favorable ADME/T profiles and drug-likeness to treat AML. In summary, AML shows response to IQGAP1 inhibition, and UR778Br, identified through in-silico studies, selectively targeted AML cells while sparing normal marrow. [ABSTRACT FROM AUTHOR]

Ethyl pyruvate (EP) is a redox-active compound that has been previously shown to be effective in restraining immune hyperactivity in animal models of various autoimmune and chronic inflammatory diseases. Importantly, EP has also been proven to have a potent tolerogenic effect on dendritic cells (DCs). Here, the influence of EP on the signaling pathways in DCs relevant for their tolerogenicity, including anti-inflammatory NRF2 and pro-inflammatory NF-κB, was explored. Specifically, the effects of EP on DCs obtained by GM-CSF-directed differentiation of murine bone marrow precursor cells and matured under the influence of lipopolysaccharide (LPS) were examined via immunocytochemistry and RT-PCR. EP counteracted LPS-imposed morphological changes and down-regulated the LPS-induced expression of pro-inflammatory mediators in DCs. While it reduced the activation of NF-κB, EP potentiated NRF2 and downstream antioxidative molecules, thus implying the regulation of NRF2 signaling pathways as the major reason for the tolerizing effects of EP on DCs. [ABSTRACT FROM AUTHOR]

Maternal obesity and over/undernutrition can have a long-lasting impact on offspring health during critical periods in the first 1000 days of life. Children born to mothers with obesity have reduced immune responses to stimuli which increase susceptibility to infections. Recently, maternal western-style diets (WSDs), high in fat and simple sugars, have been associated with skewing neonatal immune cell development, and recent evidence suggests that dysregulation of innate immunity in early life has long-term consequences on metabolic diseases and behavioral disorders in later life. Several factors contribute to abnormal innate immune tolerance or trained immunity, including changes in gut microbiota, metabolites, and epigenetic modifications. Critical knowledge gaps remain regarding the mechanisms whereby these factors impact fetal and postnatal immune cell development, especially in precursor stem cells in bone marrow and fetal liver. Components of the maternal microbiota that are transferred from mothers consuming a WSD to their offspring are understudied and identifying cause and effect on neonatal innate and adaptive immune development needs to be refined. Tools including single-cell RNA-sequencing, epigenetic analysis, and spatial location of specific immune cells in liver and bone marrow are critical for understanding immune system programming. Considering the vital role immune function plays in offspring health, it will be important to understand how maternal diets can control developmental programming of innate and adaptive immunity. [ABSTRACT FROM AUTHOR]

Astatine (211At) is a cyclotron-produced alpha emitter with a physical half-life of 7.2 h. In our previous study, the 211At-labeled prostate-specific membrane antigen (PSMA) compound ([211At]PSMA-5) exhibited excellent tumor growth suppression in a xenograft model. We conducted preclinical biodistribution and toxicity studies for the first-in-human clinical trial. [211At]PSMA-5 was administered to both normal male ICR mice (n = 85) and cynomolgus monkeys (n = 2). The mice were divided into four groups for the toxicity study: 5 MBq/kg, 12 MBq/kg, 35 MBq/kg, and vehicle control, with follow-ups at 1 day (n = 10 per group) and 14 days (n = 5 per group). Monkeys were observed 24 h post-administration of [211At]PSMA-5 (9 MBq/kg). Blood tests and histopathological examinations were performed at the end of the observation period. Blood tests in mice indicated no significant myelosuppression or renal dysfunction. However, the monkeys displayed mild leukopenia 24 h post-administration. Despite the high accumulation in the kidneys and thyroid, histological analysis revealed no abnormalities. On day 1, dose-dependent single-cell necrosis/apoptosis was observed in the salivary glands of mice and intestinal tracts of both mice and monkeys. Additionally, tingible body macrophages in the spleen and lymph nodes indicated phagocytosis of apoptotic B lymphocytes. Cortical lymphopenia (2/10) in the thymus and a decrease in the bone marrow cells (9/10) were observed in the 35 MBq/kg group in mice. These changes were transient, with no irreversible toxicity observed in mice 14 days post-administration. This study identified no severe toxicities associated with [211At]PSMA-5, highlighting its potential as a next-generation targeted alpha therapy for prostate cancer. The sustainable production of 211At using a cyclotron supports its applicability for clinical use. [ABSTRACT FROM AUTHOR]

Periodontal disease is characterized by inflammation and bone loss. Central to its pathogenesis is the dysregulated inflammatory response, complicating regenerative therapies. Mesenchymal stem cells (MSCs) hold significant promise in tissue repair and regeneration. This study investigated the effects of specialized pro-resolving mediators (SPMs), Resolvin E1 (RvE1) and Maresin 1 (MaR1), on the osteogenic differentiation of human bone marrow-derived MSCs under inflammatory conditions. The stem cells were treated with SPMs in the presence of lipopolysaccharide (LPS) to simulate an inflammatory environment. Osteogenic differentiation was assessed through alkaline phosphatase activity and alizarin red staining. Proteomic analysis was conducted to characterize the protein expression profile changes, focusing on proteins related to osteogenesis and osteoclastogenesis. Treatment with RvE1 and MaR1, both individually and in combination, significantly enhanced calcified deposit formation. Proteomic analysis revealed the differential expression of proteins associated with osteogenesis and osteoclastogenesis, highlighting the modulatory impact of SPMs on bone metabolism. RvE1 and MaR1 promote osteogenic differentiation of hBMMSCs in an inflammatory environment, with their combined application yielding synergistic effects. This study provides insights into the therapeutic potential of SPMs in enhancing bone regeneration, suggesting a promising avenue for developing regenerative therapies for periodontal disease and other conditions characterized by inflammation-induced bone loss. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a chronic B-cell lymphoproliferative disorder characterized by lymphoplasmacytic cell overgrowth in the bone marrow and increased secretion of IgM immunoglobulins into the serum. Patients with WM have a variety of clinical outcomes, including long-term survival but inevitable recurrence. Recent advances in disease knowledge, including molecular and genetic principles with the discovery of MYD88 and CXCR4 mutations, have rapidly increased patient-tolerable treatment options. WM patients may benefit from chemotherapy regimens that include rituximab-based regimens, alkylating drugs, proteasome inhibitors, monoclonal antibodies, and drugs targeting Bruton tyrosine kinase inhibitors. In light of these advancements, patients can now receive treatment customized to their specific clinical characteristics, focusing on enhancing the depth and durability of their response while limiting the adverse effects. Despite the rapidly developing therapeutic armament against WM, a lack of high-quality evidence from extensive phase 3 trials remains a significant challenge in the research. We believe clinical outcomes will keep improving when new medicines are introduced while preserving efficacy and minimizing toxicity. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a hematological malignancy caused by the clonal expansion of malignant plasma cells in the bone marrow. Myeloma cells are susceptible to killing by natural killer (NK) cells, but NK cells fail to control disease progression, suggesting immunosuppression. The activation threshold of NK-effector function is regulated by interaction between KIRs and self-HLA class I, during a process called "education" to ensure self-tolerance. NK cells can respond to diseased cells based on the absence of HLA class I expression ("Missing-self" hypothesis). The HLA and KIR repertoire is extremely diverse; thus, the present study aimed to characterize potential variances in genotypic composition of HLA Class I NK-epitopes and KIRs between MM patients and healthy controls. Genotypic expression of KIR and HLA (HLA-C group-C1/C2 and Bw4 motifs (including HLA-A*23, A*24, A*32) were analyzed in 172 MM patients and 195 healthy controls. Compared to healthy controls, we did not observe specific KIR genes or genotypes, or HLA NK-epitopes with higher prevalence among MM patients. The presence of all three HLA NK-epitopes (C1+C2+Bw4+) was not associated with MM occurrence. However, MM patients were more likely to be C1-/C2+/Bw4+ (p = 0.049, OR 1.996). In line with this, there was a trend of increased genetic co-occurrence of Bw4 and KIR3DL1 in MM patients (p = 0.05, OR 1.557). Furthermore, MM patients were more likely to genetically express both C2/KIR2DL1 and Bw4/KIR3DL1 (p = 0.019, OR 2.453). Our results reveal an HLA NK-epitope combination that is associated with the occurrence of MM. No specific KIR genotypes were associated with MM. [ABSTRACT FROM AUTHOR]

Postmenopausal osteoporosis (PMOP) affects hundreds of millions of elderly women worldwide. The imbalance between osteoblast‐mediated bone formation and osteoclast‐mediated bone resorption is the key factor in the progression of PMOP. Recently, exosomal circular RNAs have been considered as critical regulators in physiological and pathological progress. However, their roles in PMOP still require further exploration. Herein, we identified that the expression of exosomal circFAM63B significantly increased in PMOP patients and is closely related to bone density. We further demonstrated that circFAM63B inhibits osteogenic differentiation of bone marrow stromal cells and bone formation in ovariectomy mice by using a combination of in vitro and in vivo experiment strategies. Mechanistically, circFAM63B promotes HMGA2 expression by inhibiting miR‐578, thereby suppressing bone repair. Our study proved that exosomal circFAM63B suppresses the bone regeneration of PMOP by regulating the miR‐578/HMGA2 axis, which may provide new insights into the pathogenesis and development of PMOP. Knocking down exosomal circFAM63B could be regarded as a new strategy for the treatment of PMOP. [ABSTRACT FROM AUTHOR]

Liver‐X receptors (LXRs) are essential nuclear hormone receptors involved in cholesterol and lipid metabolism. They are also believed to regulate inflammation and physiological and pathological bone turnover. We have previously shown that infection with the periodontal pathogen Porphyromonas gingivalis (Pg) in mice increases the abundance of CD11b+c‐fms+Ly6Chi cells in bone marrow (BM), spleen (SPL), and peripheral blood. These cells also demonstrated enhanced osteoclastogenic activity and a distinctive gene profile following Pg infection. Here, we investigated the role of LXRs in regulating these osteoclast precursors (OCPs) and periodontal bone loss. We found that Pg infection downregulates the gene expression of LXRs, as well as ApoE, a transcription target of LXRs, in CD11b+c‐fms+Ly6Chi OCPs. Activation of LXRs by treatment with GW3965, a selective LXR agonist, significantly decreased Pg‐induced accumulation of CD11b+c‐fms+Ly6Chi population in BM and SPL. GW3965 treatment also significantly suppressed the osteoclastogenic potential of these OCPs induced by Pg infection. Furthermore, the activation of LXRs reduces the abundance of OCPs systemically in BM and locally in the periodontium, as well as mitigates gingival c‐fms expression and periodontal bone loss in a ligature‐induced periodontitis model. These data implicate a novel role of LXRs in regulating OCP abundance and osteoclastogenic potential in inflammatory bone loss. [ABSTRACT FROM AUTHOR]

Background: T-cell acute lymphoblastic leukemia (T-ALL) represents a rare and clinically and genetically heterogeneous disease that constitutes 10–15% of newly diagnosed pediatric ALL cases. Despite improved outcomes of these children, the survival rate after relapse is extremely poor. Moreover, the survivors must also endure the acute and long-term effects of intensive therapy. Although recent studies have identified a number of recurrent genomic aberrations in pediatric T-ALL, none of the changes is known to have prognostic significance. The aim of our study was to analyze the cytogenomic changes and their various combinations in bone marrow cells of children with T-ALL and to correlate our findings with the clinical features of the subjects and their treatment responses. Results: We performed a retrospective and prospective comprehensive cytogenomic analysis of consecutive cohort of 66 children (46 boys and 20 girls) with T-ALL treated according to BFM-based protocols and centrally investigated cytogenetics and immunophenotypes. Using combinations of cytogenomic methods (conventional cytogenetics, FISH, mFISH/mBAND, arrayCGH/SNP and MLPA), we identified chromosomal aberrations in vast majority of patients (91%). The most frequent findings involved the deletion of CDKN2A/CDKN2B genes (71%), T-cell receptor (TCR) loci translocations (27%), and TLX3 gene rearrangements (23%). All chromosomal changes occurred in various combinations and were rarely found as a single abnormality. Children with aberrations of TCR loci had a significantly better event free (p = 0.0034) and overall survival (p = 0.0074), all these patients are living in the first complete remission. None of the abnormalities was an independent predictor of an increased risk of relapse. Conclusions: We identified a subgroup of patients with TCR aberrations (both TRA/TRD and TRB), who had an excellent prognosis in our cohort with 5-year EFS and OS of 100%, regardless of the presence of other abnormality or the translocation partner. Our data suggest that escalation of treatment intensity, which may be considered in subsets of T-ALL is not needed for nonHR (non-high risk) patients with TCR aberrations. [ABSTRACT FROM AUTHOR]

A causal relationship exists among the aging process, organ decay and disfunction, and the occurrence of various diseases including cancer. A genetically engineered mouse model, termed Klf1K74R/K74R or Klf1(K74R), carrying mutation on the well-conserved sumoylation site of the hematopoietic transcription factor KLF1/EKLF has been generated that possesses extended lifespan and healthy characteristics, including cancer resistance. We show that the healthy longevity characteristics of the Klf1(K74R) mice, as exemplified by their higher anti-cancer capability, are likely gender-, age-, and genetic background-independent. Significantly, the anti-cancer capability, in particular that against melanoma as well as hepatocellular carcinoma, and lifespan-extending property of Klf1(K74R) mice, could be transferred to wild-type mice via transplantation of their bone marrow mononuclear cells at a young age of the latter. Furthermore, NK(K74R) cells carry higher in vitro cancer cell-killing ability than wild-type NK cells. Targeted/global gene expression profiling analysis has identified changes in the expression of specific proteins, including the immune checkpoint factors PDCD and CD274, and cellular pathways in the leukocytes of the Klf1(K74R) that are in the directions of anti-cancer and/or anti-aging. This study demonstrates the feasibility of developing a transferable hematopoietic/blood system for long-term anti-cancer and, potentially, for anti-aging. [ABSTRACT FROM AUTHOR]

BACKGROUND: Osteoporosis is a disease in which bone density and structure are destroyed and fractures are caused by increased bone fragility, leading to high clinical disability and mortality rates. OBJECTIVE: To review the research progress in the role of bone immunity in physiological and pathological processes related to bone metabolism, providing ideas for the research and clinical application of bone immunity in bone diseases. METHODS: The first author searched PubMed and CNKI databases in November 2022 for relevant literature using the keywords of “osteoimmunology, immuno-skeletal interface, bone metabolism, skeletal metabolism, lymphocyte, immune factor” in English and Chinese, respectively. The time range of retrieval was mainly from January 2010 to November 2022, and a small number of classical long-term literatures were included. After reading the topic and abstract for preliminary screening and excluding repetitive studies, low-quality journals and unrelated literature, 81 documents were finally included for review. RESULTS AND CONCLUSION: Osteoimmunology refers to that bone and immune cells share the same microenvironment and interact with each other to jointly perform the “bone immune system,” which includes all cells in the bone marrow. Immuno-skeletal interface has protective effects on bone under physiological conditions, but it may lead to bone destruction under pathological conditions. Osteoprotegerin is mainly derived from B cells and can inhibit osteoclast metabolism. However, when the body is in an inflammatory state, T cells and B cells work together to promote bone resorption. In addition, interleukin-1, interleukin-6 and tumor necrosis factor-α regulate the expression of receptor activator of nuclear factor-κB ligand in vivo and affect bone metabolism. In most clinical diseases (such as rheumatoid arthritis, estrogen deficiency, HIV infection, and hyperparathyroidism), the immuno-skeletal interface interacts with the bone immune system, resulting in the regulation of bone metabolism. In terms of clinical prospect, the interaction between bone immunity and bone metabolism should be studied in order to propose new strategies for therapeutic intervention to reduce the risk of fracture. [ABSTRACT FROM AUTHOR]

BACKGROUND: HLA haploid allogeneic hematopoietic stem cell transplantation provides a chance of survival for patients with high-risk hematologic malignancies. In recent years, the research on the transplantation mode and graft selection of haploidentical transplantation is still ongoing. At present, the mixed transplantation model of non-extracorporeal T-cell removal bone marrow and peripheral blood stem cells established by the Hematology Research Center of Peking University is gradually becoming popular in China, but this model requires the collection of donor bone marrow fluid, which increases the pain and risk of the donor. OBJECTIVE: To explore the curative effect of infusion of umbilical cord mesenchymal stem cells replacing donor bone marrow cells in haploidentical peripheral blood hematopoietic stem cell transplantation for malignant hematological diseases. METHODS: Fifty hematological malignancies patients who underwent haploidentical hematopoietic stem cell transplantation from January 2019 to May 2022 were selected and randomly assigned to two study groups at a ratio of 2:3. Among them, 19 patients received umbilical cord mesenchymal stem cell combined with peripheral blood stem cell transplantation, and 31 patients were treated with bone marrow cells combined with peripheral blood stem cells. The study was approved by the Ethics Committee of Henan Provincial People’s Hospital. The recipients of umbilical cord mesenchymal stem cells were first transfused with third-party umbilical cord mesenchymal stem cells (1×106 /kg) on the day of transplantation, followed by peripheral blood hematopoietic stem cells 6 hours later. In the bone marrow group, donor bone marrow cells were transfused +1 day after transplantation and peripheral blood stem cells were transfused +2 days after transplantation. After transplantation, rabbit anti-human thymocyte immunoglobulin, cyclosporine A, mycophenolate mofetil, and a short-course methotrexate were used for graft-versus-host disease prophylaxis for all recipients. RESULTS AND CONCLUSION: No adverse events occurred during the reinfusion of umbilical cord mesenchymal stem cells. There were no significant differences between the mesenchymal stem cell group and the bone marrow group in the engraftment rate [100% (19/19) vs. 96.8%(30/31), P > 0.05], median duration for neutrophil engraftment (14 days vs.15 days, P > 0.05) and median duration for platelet engraftment (20 days vs.19 days, P > 0.05). The incidence of grade IIIV acute graft-versus-host disease in the mesenchymal stem cell group was significantly lower than in the bone marrow group [21.1% (4/19) vs. 58.1% (18/31), P = 0.01]. There were no significant differences between the two groups in the incidence of chronic graft-versus-host disease [21.1% (4/19) vs. 25.8% (8/31), P > 0.05], the relapse rates [15.8% (3/19) vs. 16.1% (5/31), P > 0.05] and the incidence of early cytomegalovirus viremia [42.1% (8/19) vs. 35.5% (11/31), P > 0.05], and the 2-year overall survival rate [68.4% (10/19) vs. 70.9% (16/31), P > 0.05]. It is indicated that umbilical cord mesenchymal stem cells replace donor bone marrow cells in haploidentical peripheral blood stem cell transplantation for malignant hematological diseases, which reduced the incidence of acute graft-versus-host disease after transplantation, did not increase the incidence of chronic graft-versus-host disease, recurrence rate and early cytomegalovirus viremia, and reduced the pain and risk of donor pulp extraction. [ABSTRACT FROM AUTHOR]

Background: Cell-based therapy represents a potential treatment for ischemic stroke (IS). Here, we performed a systematic review and meta-analysis to summarize the evidence provided by randomized controlled trials (RCTs) for the transplantation of bone marrow mononuclear cells (BMMNCs) in patients with IS in any phase after stroke. Methods: We searched several databases for relevant articles up to the 10th of March 2023, including MEDLINE, EMBASE, the Cochrane Library, and ClinicalTrials.gov. Subgroup analyses were implemented to evaluate the dose and route of BMMNC administration. Statistical data were analyzed by Review Manager version 5.3 software. Results: Six RCTs were included in this article, including 177 patients who were treated by the transplantation of BMMNCs and 166 patients who received medical treatment. The three-month National Institutes of Health Stroke Scale (NIHSS) score indicated a favorable outcome for the BMMNC transplantation group (standardized mean difference (SMD), − 0.34; 95% confidence interval (CI), − 0.57 to − 0.11; P = 0.004). There were no significant differences between the two groups at six months post-transplantation with regards to NIHSS score (SMD 0.00; 95% CI − 0.26 to 0.27; P = 0.97), modified Rankin Scale (risk ratio (RR) 1.10; 95% CI 0.75 to 1.63; P = 0.62), Barthel Index change (SMD 0.68; 95% CI − 0.59 to 1.95; P = 0.29), and infarct volume change (SMD − 0.08; 95% CI − 0.42 to 0.26; P = 0.64). In addition, there was no significant difference between the two groups in terms of safety outcome (RR 1.24; 95% CI 0.80 to 1.91; P = 0.33). Conclusion: Our meta-analysis demonstrated that the transplantation of BMMNCs was safe; however, the efficacy of this procedure requires further validation in larger RTCs. [ABSTRACT FROM AUTHOR]

In the adult bone marrow (BM), endothelial cells (ECs) are an integral component of the hematopoietic stem cell (HSC)-supportive niche, which modulates HSC activity by producing secreted and membrane-bound paracrine signals. Within the BM, distinct vascular arteriole, transitional, and sinusoidal EC subtypes display unique paracrine expression profiles and create anatomically-discrete microenvironments. However, the relative contributions of vascular endothelial subtypes in supporting hematopoiesis is unclear. Moreover, constitutive expression and off-target activity of currently available endothelial-specific and endothelial-subtype-specific murine cre lines potentially confound data analysis and interpretation. To address this, we describe two tamoxifen-inducible cre-expressing lines, Vegfr3-creERT2 and Cx40-creERT2, that efficiently label sinusoidal/transitional and arteriole endothelium respectively in adult marrow, without off-target activity in hematopoietic or perivascular cells. Utilizing an established mouse model in which cre-dependent recombination constitutively-activates MAPK signaling within adult endothelium, we identify arteriole ECs as the driver of MAPK-mediated hematopoietic dysfunction. These results define complementary tamoxifen-inducible creERT2-expressing mouse lines that label functionally-discrete and non-overlapping sinusoidal/transitional and arteriole EC populations in the adult BM, providing a robust toolset to investigate the differential contributions of vascular subtypes in maintaining hematopoietic homeostasis. [ABSTRACT FROM AUTHOR]

The broad spectrum of brain injuries in preterm newborns and the plasticity of the central nervous system prompts us to seek solutions for neurodegeneration to prevent the consequences of prematurity and perinatal problems. The study aimed to evaluate the safety and efficacy of the implantation of autologous bone marrow nucleated cells and bone marrow mesenchymal stem cells in different schemes in patients with hypoxic-ischemic encephalopathy and immunological encephalopathy. Fourteen patients received single implantation of bone marrow nucleated cells administered intrathecally and intravenously, followed by multiple rounds of bone marrow mesenchymal stem cells implanted intrathecally, and five patients were treated only with repeated rounds of bone marrow mesenchymal stem cells. Seizure outcomes improved in most cases, including fewer seizures and status epilepticus and reduced doses of antiepileptic drugs compared to the period before treatment. The neuropsychological improvement was more frequent in patients with hypoxic-ischemic encephalopathy than in the immunological encephalopathy group. Changes in emotional functioning occurred with similar frequency in both groups of patients. In the hypoxic-ischemic encephalopathy group, motor improvement was observed in all patients and the majority in the immunological encephalopathy group. The treatment had manageable toxicity, mainly mild to moderate early-onset adverse events. The treatment was generally safe in the 4-year follow-up period, and the effects of the therapy were maintained after its termination. [ABSTRACT FROM AUTHOR]

Blood count is crucial for assessing bone marrow's cell production and differentiation during infections, gaging disease severity, and monitoring therapeutic responses. The profile of blood count in chronic forms of paracoccidioidomycosis (PCM) has been insufficiently explored. To better understand the changes in hematological cells in different stages of the PCM chronic form, we evaluated the blood count, including immature blood cells in automated equipment, before and during the treatment follow-up of 62 chronic PCM patients. Predominantly male (96.8%) with an average age of 54.3 (standard deviation SD 6.9) years, participants exhibited pre-treatment conditions such as anemia (45.2%), monocytosis (38.7%), and leukocytosis (17.7%), which became less frequent after clinical cure. Anemia was more prevalent in severe cases. Notably, hemoglobin and reticulocyte hemoglobin content increased, while leukocytes, monocytes, neutrophils, immature granulocytes, and platelets decreased. Chronic PCM induced manageable hematological abnormalities, mainly in the red blood series. Monocytosis, indicating monocytes' role in PCM's immune response, was frequent. Post-treatment, especially after achieving clinical cure, significant improvements were observed in various hematological indices, including immature granulocytes and reticulocyte hemoglobin content, underscoring the impact of infection on these parameters. [ABSTRACT FROM AUTHOR]

B cell receptor-associated protein 31 (BAP31) is a transmembrane protein that is widely expressed and primarily located in the endoplasmic reticulum (ER). B cells play a crucial role in the immune system, and BAP31 significantly contributes to the functions of various immune cells. However, the specific role of BAP31 in B lymphocytes development remains unknown. In this study, we utilized a mouse model with BAP31 deleted from B cells to investigate its effects. Our findings reveal a block in early B cell development in the bone marrow and a significant decrease in the number of B cells in peripheral lymphoid organs taken from BAP31 B cell conditional knockout (BAP31-BCKO) mice. B cell receptor (BCR) signaling is crucial for the normal development and differentiation of B lymphocytes. BAP31, an endoplasmic reticulum membrane protein, directly regulates the BCR signaling pathway and was shown to be significantly positively correlated with B cell activation and proliferation. These findings establish BAP31 as a crucial regulator of early B cell development. [ABSTRACT FROM AUTHOR]

Background: The immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is crucial for preventing infections and relapse and enhancing graft‐versus‐tumor effects. B cells play an important role in humoral immunity and immune regulation, but their reconstitution after allo‐HSCT has not been well studied. Methods: In this study, we analyzed the dynamics of B cells in 252 patients who underwent allo‐HSCT for 2 years and assessed the impact of factors on B‐cell reconstitution and their correlations with survival outcomes, as well as the development stages of B cells in the bone marrow and the subsets in the peripheral blood. Results: We found that the B‐cell reconstitution in the bone marrow was consistent with the peripheral blood (p = 0.232). B‐cell reconstitution was delayed by the male gender, age >50, older donor age, the occurrence of chronic and acute graft‐versus‐host disease, and the infections of fungi and cytomegalovirus. The survival analysis revealed that patients with lower B cells had higher risks of death and relapse. More importantly, we used propensity score matching to obtain the conclusion that post‐1‐year B‐cell reconstitution is better in females. Meanwhile, using mediation analysis, we proposed the age‐B cells‐survival axis and found that B‐cell reconstitution at month 12 posttransplant mediated the effect of age on patient survival (p = 0.013). We also found that younger patients showed more immature B cells in the bone marrow after transplantation (p = 0.037). Conclusion: Our findings provide valuable insights for optimizing the management of B‐cell reconstitution and improving the efficacy and safety of allo‐HSCT. [ABSTRACT FROM AUTHOR]

Introduction: Low energy availability due to excessive exercise lowers bone mass and impairs various physiological functions, including immunity and hematopoiesis. We focused on Cxcl12 abundant reticular (CAR) cells, which are bone marrow mesenchymal stem cells and are essential for the maintenance of hematopoietic and immune cells in bone marrow. We examine the functional changes in CAR cells resulting from dietary restriction combined with exercise. Materials and methods: Five-week-old wild-type female mice were divided into an ad libitum group (CON), a 60% dietary restriction group (DR), an ad libitum with exercise group (CON + ex), and a 60% dietary restriction with exercise group (DR + ex). Blood parameters, bone structure parameters, and bone marrow fat volume were evaluated after 5 weeks. In addition, bone marrow CAR cells were isolated by cell sorting and analyzed for gene expression by RT-qPCR. Results: Bone mineral density (BMD) was significantly decreased in DR and DR + ex compared to CON and CON + ex. Especially, cortical bone mass and thickness were significantly decreased in DR and DR + ex groups, whereas trabecular bone mass was significantly increased. Bone marrow fat volume was significantly increased in DR and DR + ex groups compared to CON and CON + ex. The number of leukocytes in the blood was significantly decreased in the DR + ex group compared to the other three groups. RT-qPCR showed a significant decrease in gene expression of both Foxc1 and Runx2 in CAR cells of the DR + ex group compared to CON. Conclusion: Dietary restriction combined with exercise promotes CAR cell differentiation into bone marrow adipocyte and suppresses osteoblast differentiation. [ABSTRACT FROM AUTHOR]

The primary cilium is a solitary, sensory organelle with many roles in bone development, maintenance, and function. In the osteogenic cell lineage, including skeletal stem cells, osteoblasts, and osteocytes, the primary cilium plays a vital role in the regulation of bone formation, and this has made it a promising pharmaceutical target to maintain bone health. While the role of the primary cilium in the osteogenic cell lineage has been increasingly characterized, little is known about the potential impact of targeting the cilium in relation to osteoclasts, a hematopoietic cell responsible for bone resorption. The objective of this study was to determine whether osteoclasts have a primary cilium and to investigate whether or not the primary cilium of macrophages, osteoclast precursors, serves a functional role in osteoclast formation. Using immunocytochemistry, we showed the macrophages have a primary cilium, while osteoclasts lack this organelle. Furthermore, we increased macrophage primary cilia incidence and length using fenoldopam mesylate and found that cells undergoing such treatment showed a significant decrease in the expression of osteoclast markers tartrate-resistant acid phosphatase, cathepsin K, and c-Fos, as well as decreased osteoclast formation. This work is the first to show that macrophage primary cilia resorption may be a necessary step for osteoclast differentiation. Since primary cilia and preosteoclasts are responsive to fluid flow, we applied fluid flow at magnitudes present in the bone marrow to differentiating cells and found that osteoclastic gene expression by macrophages was not affected by fluid flow mechanical stimulation, suggesting that the role of the primary cilium in osteoclastogenesis is not a mechanosensory one. The primary cilium has been suggested to play a role in bone formation, and our findings indicate that it may also present a means to regulate bone resorption, presenting a dual benefit of developing ciliary-targeted pharmaceuticals for bone disease. [ABSTRACT FROM AUTHOR]

The automatic detection of bone marrow (BM) cell diseases plays a vital role in the medical field; it helps to make diagnoses more precise and effective, which leads to early detection and can significantly improve patient outcomes and increase the chances of successful intervention. This study proposed a fully automated intelligent system for BM classification by developing and enhancing Capsule Neural Network (CapsNet) architecture. Although CapsNet has demonstrated success in many classification tasks, it still has some limitations and challenges associated with using Convolutional Neural Networks (CNNs), which suffer from information loss during the pooling and discarding of detailed spatial information, resulting in the loss of fine‐grained features. Additionally, CNNs must help capture hierarchical feature relationships and often learn them implicitly by stacking convolutional layers. In contrast, CapsNets are designed to capture hierarchical features through dynamic routing and relationships between capsules, resulting in a more explicit representation of spatial hierarchy. CapsNets manage transformations and offer equivariance, preserving spatial information through capsule routing mechanisms. Further, to improve how features are represented, pre‐trained models such as Residual Capsule Network (RES‐CapsNet), Visual Geometry Group Capsule Network (VGG‐CapsNet), and Google Network (Inception V3) (GN‐CapsNet) have been used. This helps the network obtain the low‐ and mid‐level features and information it has previously learned so that subsequent capsule layers receive better initial information. Additionally, the Synthetic Minority Over‐Sampling Technique (SMOTE) was implemented to mitigate class imbalance. It generates synthetic samples in feature space by over‐sampling the minority class, leading to improving model performance in accurately classifying rare instances. Fine‐tuning the hyperparameters and implementing these improvements resulted in remarkable accuracy rates on a large BM dataset, with reduced training time and trainable parameters. CapsNet achieved 96.99%, VGG‐CapsNet achieved 98.95%, RES‐CapsNet achieved 99.24%, and the GN‐CapsNet model demonstrated superior accuracy at 99.45%. GN‐Caps Net was the best because it requires a small number of epochs and has an effective deep inception architecture that efficiently extracts features at different scales to form a robust representation of the input. Our proposed models were compared with existing state‐of‐the‐art models using the BM dataset; the results showed that our models outperformed the existing approaches and demonstrated excellent performance. Further, this automated system can analyze large amounts of data and complex cells in images of the BM dataset. Thus, it gives healthcare professionals a detailed understanding of different diseases, which may take time to achieve manually. [ABSTRACT FROM AUTHOR]

Summary: Bone marrow (BM) examination is a key element in the diagnosis and prognostic grading of myelodysplastic syndromes (MDSs), and obtaining adequate BM cell samples is critical for accurate test results. Massive haemodilution of aspirated BM samples is a well‐known problem; however, its incidence in patients with MDS has not been well studied. We report the first study to examine the incidence of massive haemodilution in nationwide BM samples aspirated from patients diagnosed with or suspected of MDS in Japan. Among 283 cases available for analysis, BM smears from 92 cases (32.5%) were hypospicular (massively haemodiluted) and, particularly, no BM particles were observed in 52 cases (18.4%). Regarding hypospicular cases, we examined how the doctors in charge interpreted the BM smears of their patients. In only 19 of 92 cases (20.7%), doctors realised that the BM smears were haemodiluted. Furthermore, the BM biopsy, which can help diagnose hypospicular cases, was oftentimes not performed when the haemodilution was overlooked by doctors (not performed in 50 of 73 such cases). These real‐world data highlight that not only researchers who are working to improve diagnostic tests but also clinicians who perform and use diagnostic tests must realise this common and potentially critical problem. [ABSTRACT FROM AUTHOR]

NOD-like receptor family CARD domain containing 3 (NLRC3) is the intracellular protein belonging to NLR (NOD-like receptor) family. NLRC3 can negatively regulate inflammatory signal transduction pathways within the adaptive and innate immunocytes. However, studies need to elucidate the biological role of NLRC3 in bone remodeling. Herein, our study proved that NLRC3 prevents bone loss by inhibiting TNFα+ Th17 cell responses. In osteoporosis, NLRC3 attenuated TNFα+ Th17 cell accumulation in the bone marrow. However, osteoporosis (OP) development was aggravated without affecting bone marrow macrophage (BMM) osteoclastogenesis in NLRC3-deficient ovariectomized (OVX) mice. In this study, we transferred the wild-type and NLRC3−/− CD4+ cells into Rag1−/− mice. Consequently, we evidenced the effects of NLRC3 in CD4+ T cells on inhibiting the accumulation of TNFα + Th17 cells, thus restricting bone loss in the OVX mice. Simultaneously, NLRC3−/− CD4+ T cells promoted the recruitment of osteoclast precursors and inflammatory monocytes into the OVX mouse bone marrow. Mechanism-wise, NLRC3 reduced the secretion of TNFα + Th17 cells of RANKL, MIP1α, and MCP1, depending on the T cells. In addition, NLRC3 negatively regulated the Th17 osteoclastogenesis promoting functions via limiting the NF-κB activation. Collectively, this study appreciated the effect of NLRC3 on modulating bone mass via adaptive immunity depending on CD4+ cells. According to findings of this study, NLRC3 may be the candidate anti-OP therapeutic target. Key messages: NLRC3 negatively regulated the Th17 osteoclastogenesis promoting functions via limiting the NF-κB activation. NLRC3 may be the candidate anti-OP therapeutic target. [ABSTRACT FROM AUTHOR]

Fat is the main component of an adult bone marrow and constitutes the so-called bone marrow adipose tissue (BMAT). Marrow adipocytes, which are the fat cells in the bone marrow, become more abundant with age, and may influence the whole-body metabolism. In osteoporotic patients, the amount of BMAT has an inverse correlation with the amount of bone mass. In people with anorexia nervosa that lose weight after the reduction of peripheral adipose tissues, BMAT expands. Although bone marrow adipocytes are increasingly recognized as a target for therapy, there is still much to learn about their role in skeletal homeostasis, metabolism, cancer, and regenerative treatments. The Bone Marrow Adiposity Society (BMAS), established in 2017, aims to enhance the understanding of how BMAT relates to bone health, cancer, and systemic metabolism. BMAS is committed to training young scientists and organized the second edition of the BMAS Summer School, held on September 4–6, 2023, as a virtual event. [ABSTRACT FROM AUTHOR]

• DC vaccine therapy in AML management. • Prospects of DC vaccination in AML. • AML patients improved via DC vaccine therapy. Acute myeloid leukemia (AML) is classified as a hematologic malignancy characterized by the proliferation of immature blood cells within the bone marrow (BM), resulting in an aberrant and unregulated cellular growth. The primary therapeutic modalities for AML include chemotherapy and hematopoietic stem cell transplantation. However, it is important to note that these treatments are accompanied by important adverse effects and mortality rates. Therefore, the need for more effective treatment options seems necessary, and dendritic cell (DC) vaccine therapy can be one of these options. In this study, we aim to investigate the effectiveness of DC vaccination therapy for the management of AML. PubMed, Scopus, ProQuest, Web of Science, and Google Scholar databases were searched for this systematic review. The articles were evaluated based on the inclusion criteria of this study and initially compared in terms of titles or abstracts. Finally, the articles related to the topic of this review were obtained in full text. The complete remission and partial remission, survival, correlative immune assays, and health-related metrics were used to evaluate this cellular immunotherapy effectiveness. The quality of the studies was assessed independently using the Cochrane risk-of-bias tools. The compiled data were input into a standard Excel spreadsheet. Each domain was evaluated as having either a "low risk," "high risk," or "unclear risk" of bias. Among the 3986 studies that were determined, a total of 11 correlated trials were selected for inclusion in this systematic review. DC vaccine therapy was effective in inducing complete and partial remission, and stabilization of the disease. Additionally, it was discovered that the treatment strengthened the immune system as seen by increased levels of CD4+ and CD8+ T cells, Th1 cytokines, WT1-specific T cells, and activated NK cells. We conducted a systematic review that supports the use of DC vaccine therapy as an effective treatment for AML. The therapy demonstrated potentials in achieving remission, enhancing the immune system function, and increasing overall survival. However, more studies are required to improve the methods of preparing and delivering the DC vaccine, and to confirm its long-term safety and effectiveness. [ABSTRACT FROM AUTHOR]

Cyclosporin A (CsA) remains a major component of immunosuppressive regimens applied in allogeneic hematopoietic stem cell transplantation (HSCT). The impact of CsA trough levels during the first weeks after HSCT has not yet been investigated specifically in anti-T-lymphocyte globulin (ATLG)-based HSCT from matched related and unrelated donors. To address this issue, we have retrospectively examined 307 consecutive matched related (n = 145) and unrelated (n = 162) HSCTs, using peripheral blood stem cells or bone marrow. HSCTs for active, uncontrolled malignancies were excluded. The initial three weeks' average mean CsA trough levels were analyzed in landmark and multi-state models, using a cut-off of 200 ng/mL. CsA levels >200 ng/mL were associated with a reduced risk of acute graft-versus-host disease (GVHD) grade 3–4 at the first-week landmark (subdistribution hazard ratio [SHR] 0.59, P = 0.03) and the second-week landmark (SHR 0.48, P = 0.004), whereas there was no impact at the third-week landmark (HR 0.87, P = 0.69). This was supported by a multi-state model, in which week 1 (hazard ratio [HR] 0.53, P = 0.006) and week 2 (HR 0.48, P = 0.003), but not week 3 (HR 0.80, P = 0.44) CsA levels >200 ng/mL were associated with a reduced acute GVHD 3–4 risk. Relapse incidence was not significantly affected by week 1 through 3 CsA levels. Despite ATLG's inherent GVHD-preventive properties, week 1 CsA trough levels >200 ng/mL following ATLG-based HSCT (n = 220) were associated with a significantly reduced risk of non-relapse mortality (SHR 0.52, P = 0.02) and improved overall survival (HR 0.61, P = 0.02). Our findings emphasize the continuing importance of ensuring CsA levels ≥200 ng/mL immediately post-transplant in the setting of ATLG-based HSCT. [Display omitted] [ABSTRACT FROM AUTHOR]

Autologous bone marrow mononuclear cells (BMMNCs) infused after severe traumatic brain injury have shown promise for treating the injury. We evaluated their impact in children, particularly their hypothesized ability to preserve the blood–brain barrier and diminish neuroinflammation, leading to structural CNS preservation with improved outcomes. We performed a randomized, double-blind, placebo-sham-controlled Bayesian dose-escalation clinical trial at two children's hospitals in Houston, TX and Phoenix, AZ, USA (NCT01851083). Patients 5–17 years of age with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8) were randomized to BMMNC or placebo (3:2). Bone marrow harvest, cell isolation and infusion were completed by 48 h post-injury. A Bayesian continuous reassessment method was used with cohorts of size 3 in the BMMNC group to choose the safest between two doses. Primary end points were quantitative brain volumes using MRI and microstructural integrity of the corpus callosum (diffusivity and oedema measurements) at 6 months and 12 months. Long-term functional outcomes and ventilator days, intracranial pressure monitoring days, intensive care unit days and therapeutic intensity measures were compared between groups. Forty-seven patients were randomized, with 37 completing 1-year follow-up (23 BMMNC, 14 placebo). BMMNC treatment was associated with an almost 3-day (23%) reduction in ventilator days, 1-day (16%) reduction in intracranial pressure monitoring days and 3-day (14%) reduction in intensive care unit (ICU) days. White matter volume at 1 year in the BMMNC group was significantly preserved compared to placebo [decrease of 19 891 versus 40 491, respectively; mean difference of −20 600, 95% confidence interval (CI): −35 868 to −5332; P = 0.01], and the number of corpus callosum streamlines was reduced more in placebo than BMMNC, supporting evidence of preserved corpus callosum connectivity in the treated groups (−431 streamlines placebo versus −37 streamlines BMMNC; mean difference of −394, 95% CI: −803 to 15; P = 0.055), but this did not reach statistical significance due to high variability. We conclude that autologous BMMNC infusion in children within 48 h after severe traumatic brain injury is safe and feasible. Our data show that BMMNC infusion led to: (i) shorter intensive care duration and decreased ICU intensity; (ii) white matter structural preservation; and (iii) enhanced corpus callosum connectivity and improved microstructural metrics. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the genoprotective activity and safety of Moringa oleifera leave and Tinospora cordifolia stem extracts against cyclophosphamide (CP)-induced genotoxicity utilizing Swiss albino mice. Animals were divided into 14 groups for subacute treatment with either M. oleifera or T. cordifolia extracts daily for 28 days. The extract doses selected were 100, 200 or 400 mg/kg b.w administered orally alone or combined with CP (50 mg/kg b.w. intraperitoneally daily for 5 days). Analyses performed included the comet assay, micronucleus test (MN) in bone marrow cells and sperm head abnormality assay (SHA). M. oleifera and T. cordifolia extracts induced no significant genotoxic effects on somatic and germ cells. In contrast, for all cells examined M. oleifera and T. cordifolia extracts inhibited DNA damage initiated by CP. Taken together data demonstrated that both plant extracts did not exhibit marked genotoxic effects but displayed potential chemoprotective properties against CP-induced genotoxicity in Swiss mice. [ABSTRACT FROM AUTHOR]

Visceral leishmaniasis (VL) is a potentially fatal parasitic infection caused by Leishmania donovani in India. L. donovani is an obligate intracellular protozoan residing mostly in macrophages of the reticuloendothelial system throughout chronic infection. Monocytic phagocytes are critical in the pathogenesis of different forms of leishmaniasis. Subsets of monocytes are distinguished by their surface markers into CD14+CD16- classical monocytes, CD14+CD16+ intermediate monocytes, and CD16++CD14low non-classical monocyte subsets. During cutaneous leishmaniasis (CL), intermediate monocyte are reported to be a source of inflammatory cytokines IL-1β and TNF, and they express CCR2 attracting them to sites of inflammatory pathology. We examined monocyte subsets in the blood and bone marrow of patients with VL from an endemic site in Bihar, India, and found these contrasted with the roles of monocytes in CL. During VL, intermediate and non-classical CD16+ monocyte subsets expressed instead a non-inflammatory phenotype with low CCR2, high CX3CR1 and low microbicidal oxidant generation, making them more similar to patrolling monocytes than inflammatory cells. Bone marrow CD16+ monocyte subsets expressed a phenotype that might be more similar to the inflammatory subsets of CL, although our inability to obtain bone marrow from healthy donors in the endemic region hampered this interpretation Overall the data suggest that CD16+ intermediate monocyte subsets in VL patients express a phenotypes that contributes to an immunosuppressed pathologic immune state, but in contrast to CL, these do not mediate localized inflammatory responses. Author summary: The parasite Leishmania donovani causes the fatal systemic disease visceral leishmaniasis (VL) in endemic nations including India. The parasite is an obligate intracellular protozoan, residing mostly in monocytic cells in the bone marrow, blood and affected organs of infected human or other vertebrate hosts. Cells of the monocytic lineage can either provide a safe intracellular location in which the parasite survives, or they can be activated to kill intracellular parasites. We studied the contribution of monocyte subsets in the blood and bone marrow of patients from India with active visceral leishmaniasis, or control subjects without leishmaniasis. Our studies suggested that circulating monocytes of patients with VL are defective in their hability to kill intracellular parasites and to migrate toward sites of inflammation. These defects are most prominent in expanded subsets of monocytes expressing both the CD16 and CD14 receptors on their surface membranes. The immune defects underlying VL may be greatly influenced by subsets of blood monocytes that expand during disease. [ABSTRACT FROM AUTHOR]

Patients with chronic myeloid leukemia (CML) who receive tyrosine kinase inhibitors (TKIs) have been known to achieve treatment-free remission (TFR) upon discontinuing treatment. However, the underlying mechanisms of this phenomenon remain incompletely understood. This study aims to elucidate the mechanism of TFR in CML patients, focusing on the feedback interaction between leukemia stem cells and the bone marrow microenvironment. We have developed a mathematical model to explore the interplay between leukemia stem cells and the bone marrow microenvironment, allowing for the simulation of CML progression dynamics. Our proposed model reveals a dichotomous response following TKI discontinuation, with two distinct patient groups emerging: one prone to early molecular relapse and the other capable of achieving long-term TFR after treatment cessation. This finding aligns with clinical observations and underscores the essential role of feedback interaction between leukemic cells and the tumor microenvironment in sustaining TFR. Notably, we have shown that the ratio of leukemia cells in peripheral blood (PBLC) and the tumor microenvironment (TME) index can be a valuable predictive tool for identifying patients likely to achieve TFR after discontinuing treatment. This study provides fresh insights into the mechanism of TFR in CML patients and underscores the significance of microenvironmental control in achieving TFR. [ABSTRACT FROM AUTHOR]

Addressing the challenges of quiescence and post-treatment relapse is of utmost importance in the microbiology field. This study shows that Leishmania infantum and L. donovani parasites rapidly enter into quiescence after an estimated 2–3 divisions in both human and mouse bone marrow stem cells. Interestingly, this behavior is not observed in macrophages, which are the primary host cells of the Leishmania parasite. Transcriptional comparison of the quiescent and non-quiescent metabolic states confirmed the overall decrease of gene expression as a hallmark of quiescence. Quiescent amastigotes display a reduced size and signs of a rapid evolutionary adaptation response with genetic alterations. Our study provides further evidence that this quiescent state significantly enhances resistance to treatment. Moreover, transitioning through quiescence is highly compatible with sand fly transmission and increases the potential of parasites to infect cells. Collectively, this work identified stem cells in the bone marrow as a niche where Leishmania quiescence occurs, with important implications for antiparasitic treatment and acquisition of virulence traits. Author summary: Quiescence and post-treatment relapse are crucial aspects of treatment failure across the microbiology field. This study shows that Leishmania infantum and L. donovani parasites rapidly enter into quiescence in both human and mouse bone marrow stem cells, but not in macrophages. Besides a reduced size, quiescent amastigotes show signs of a rapid evolutionary adaptation with notable genetic alterations. Transitioning through a quiescent state allows escape from treatment, efficient transmission by sand flies and the acquisition of an increased cellular infectivity. Transcriptional profiling of quiescent and non-quiescent parasites isolated from the stem cell niche confirmed a generalized transcriptional downregulation as a hallmark of quiescence. [ABSTRACT FROM AUTHOR]

Objective: Asthma stands as one of the most prevalent chronic respiratory conditions in children, with its pathogenesis tied to the actived antigen presentation by dendritic cells (DCs) and the imbalance within T cell subgroups. This study seeks to investigate the role of the transcription factor EB (TFEB) in modulating the antigen presentation process of DCs and its impact on the differentiation of T cell subgroups. Methods: Bone marrow dendritic cells (BMDCs) were activated using house dust mites (HDM) and underwent RNA sequencing (RNA-seq) to pinpoint differentially expressed genes. TFEB mRNA expression levels were assessed in the peripheral blood mononuclear cells (PBMCs) of both healthy children and those diagnosed with asthma. In an asthma mouse model induced by HDM, the TFEB expression in lung tissue DCs was evaluated. Further experiments involved LV-shTFEB BMDCs co-cultured with T cells to explore the influence of TFEB on DCs' antigen presentation, T cell subset differentiation, and cytokine production. Results: Transcriptomic sequencing identified TFEB as a significantly differentially expressed gene associated with immune system pathways and antigen presentation. Notably, TFEB expression showed a significant increase in the PBMCs of children diagnosed with asthma compared to healthy counterparts. Moreover, TFEB exhibited heightened expression in lung tissue DCs of HDM-induced asthmatic mice and HDM-stimulated BMDCs. Silencing TFEB resulted in the downregulation of MHC II, CD80, CD86, and CD40 on DCs. This action reinstated the equilibrium among Th1/Th2 and Th17/Treg cell subgroups, suppressed the expression of pro-inflammatory cytokines like IL-4, IL-5, IL-13, and IL-17, while augmenting the expression of the anti-inflammatory cytokine IL-10. Conclusion: TFEB might have a vital role in asthma's development by impacting the antigen presentation of DCs, regulating T cell subgroup differentiation, and influencing cytokine secretion. Its involvement could be pivotal in rebalancing the immune system in asthma. These research findings could potentially unveil novel therapeutic avenues for treating asthma. [ABSTRACT FROM AUTHOR]

The article offers information on the challenges and advancements in hematopoietic stem cell transplantation (HCT) over the past 50 years, as chronicled through key papers in the JCI. Topics include the curative potential of HCT for various hematologic diseases, the challenges of allogeneic HCT such as relapse and graft-versus-host disease (GVHD), and the immunologic complexities underlying these challenges.

Background: The use of cells as carriers for the delivery of nanoparticles is a promising approach in anticancer therapy, mainly due to their natural properties, such as biocompatibility and non-immunogenicity. Cellular carriers prevent the rapid degradation of nanoparticles, improve their distribution, reduce cytotoxicity and ensure selective delivery to the tumor microenvironment. Therefore, we propose the use of phagocytic cells as boron carbide nanoparticle carriers for boron delivery to the tumor microenvironment in boron neutron capture therapy. Results: Macrophages originating from cell lines and bone marrow showed a greater ability to interact with boron carbide (B4C) than dendritic cells, especially the preparation containing larger nanoparticles (B4C 2). Consequently, B4C 2 caused greater toxicity and induced the secretion of pro-inflammatory cytokines by these cells. However, migration assays demonstrated that macrophages loaded with B4C 1 migrated more efficiently than with B4C 2. Therefore, smaller nanoparticles (B4C 1) with lower toxicity but similar ability to activate macrophages proved to be more attractive. Conclusions: Macrophages could be promising cellular carriers for boron carbide nanoparticle delivery, especially B4C 1 to the tumor microenvironment and thus prospective use in boron neutron capture therapy. [ABSTRACT FROM AUTHOR]

The study focused on the effects of a triply periodic minimal surface (TPMS) scaffolds, varying in porosity, on the repair of mandibular defects in New Zealand white rabbits. Four TPMS configurations (40%, 50%, 60%, and 70% porosity) were fabricated with β-tricalcium phosphate bioceramic via additive manufacturing. Scaffold properties were assessed through scanning electron microscopy and mechanical testing. For proliferation and adhesion assays, mouse bone marrow stem cells (BMSCs) were cultured on these scaffolds. In vivo, the scaffolds were implanted into rabbit mandibular defects for 2 months. Histological staining evaluated osteogenic potential. Moreover, RNA-sequencing analysis and RT-qPCR revealed the significant involvement of angiogenesis-related factors and Hippo signaling pathway in influencing BMSCs behavior. Notably, the 70% porosity TPMS scaffold exhibited optimal compressive strength, superior cell proliferation, adhesion, and significantly enhanced osteogenesis and angiogenesis. These findings underscore the substantial potential of 70% porosity TPMS scaffolds in effectively promoting bone regeneration within mandibular defects. [ABSTRACT FROM AUTHOR]

Adrenal cysts lined by thyroid follicular epithelium are rare, with only 14 reported cases of "ectopic thyroid tissue" to date. While the primary consideration for differential diagnosis is thyroid carcinoma metastasis, exclusion of metastases is determined based on the absence of a primary thyroid lesion, serological euthyroidism, lack of thyroglobulin elevation, and absence of epithelial atypia. Herein, we report 2 cases of adrenal cysts lined by thyroid follicular epithelium. Case 1 was a 60-year-old woman with a right adrenal cyst. Case 2 was a 51-year-old man with a left adrenal cyst. Over time, both cysts became larger, necessitating an adrenalectomy. Cystic epithelia were lined with thyroid follicular epithelium, exhibiting moderate atypia. Human bone marrow endothelial cell marker-1 and galectin-3 were focally positive; CK19 was positive in Case 1, and all 3 markers were positive in Case 2, previously reported as an immunophenotype of thyroid carcinoma. CD56 expression was positive in both cases. Targeted next-generation sequencing revealed several low-frequency mutations; however, no major driver alterations for thyroid cancer were detected. Adrenal cysts can be lined by thyroid follicular epithelium. Challenges arise in determining the malignant or benign nature of adrenal cysts. [ABSTRACT FROM AUTHOR]

The bone marrow is a haven for hematopoietic and non-hematopoietic cells, creating complex micro-anatomical regions called niches. These distinct niches all participate in an intricate orchestra of cellular interactions that regulates the hematopoietic stem cell and its progenies. In this review, we provide a detailed description of the three most well-known bone marrow niches and their participation in hematopoiesis. We use pre-clinical data, including different in vitro and in vivo studies to discuss how a group of proteins called Semaphorins could potentially modulate both hematopoietic and non-hematopoietic cells, establishing links between the niches, semaphorins, and hematopoietic regulation. Thus, here we provide a deep dive into the inner functioning of the bone marrow and discuss the overarching implications that semaphorins might have on blood formation. [Display omitted] • Semaphorins represent a large group of proteins with diverse effects. • Semaphorins can influence multiple cells of the bone marrow niche. • The effects of Semaphorins over the bone marrow niche remains unexplored. • Semaphorins have potential applications to the regulation of hematopoietic cells. [ABSTRACT FROM AUTHOR]

The clinical signs of multiple myeloma, a plasma cell (PC) dyscrasia, include bone loss, renal damage, and paraproteinemia. It can be defined as the uncontrolled growth of malignant PCs within the bone marrow. The distinctive bone marrow milieu that regulates the progression of myeloma disease involves interactions between plasma and stromal cells, and myeloid and lymphoid cells. These cells affect the immune system independently or because of a complicated web of interconnections, which promotes disease development and immune evasion. Due to the importance of these factors in the onset of disease, various therapeutic strategies have been created that either target or improve the immunological processes that influence disease progression. The immune system has a role in the mechanism of action of multiple myeloma treatments. The main contributions of immune cells to the bone marrow microenvironment, as well as how they interact and how immune regulation might lead to therapeutic effects, are covered in this study. [ABSTRACT FROM AUTHOR]

Background and Purpose: Psoriasis is a common autoimmune skin disease that significantly diminishes patients' quality of life. Interactions between primary afferents of the somatosensory system and the cutaneous immune system mediate the pathogenesis of psoriasis. This study aims to elucidate the molecular mechanisms of how primary sensory neurons regulate psoriasis formation. Experimental Approach: Skin and total RNA were extracted from wild‐type (WT) and ASH1‐like histone lysine methyltransferase (Ash1l+/−) mice in both naive and imiquimod (IMQ)‐induced psoriasis models. Immunohistochemistry, quantitative real‐time polymerase chain reaction (qRT‐PCR) and fluorescence‐activated cell sorting (FACS) were then performed. Microfluidic chamber coculture was used to investigate the interaction between somatosensory neurons and bone marrow dendritic cells (BMDCs) ex vivo. Whole‐cell patch clamp recordings were used to evaluate neuronal excitability after Ash1L haploinsufficiency in primary sensory neurons. Key Results: The haploinsufficiency of ASH1L, a histone methyltransferase, in primary sensory neurons causes both neurite hyperinnervation and increased neuronal excitability, which promote miR‐let‐7b release from primary afferents in the skin in a neuronal activity‐dependent manner. With a 'GUUGUGU' core sequence, miR‐let‐7b functions as an endogenous ligand of toll‐like receptor 7 (TLR7) and stimulates the activation of dermal dendritic cells (DCs) and interleukin (IL)‐23/IL‐17 axis, ultimately exacerbating the symptoms of psoriasis. Thus, by limiting miR‐let‐7b release from primary afferents, ASH1L prevents dermal DC activation and ameliorates psoriasis. Conclusion and Implications: Somatosensory neuron ASH1L modulates the cutaneous immune system by limiting neuronal activity‐dependent release of miR‐let‐7b, which can directly activate dermal DCs via TLR7 and ultimately lead to aggravated psoriatic lesion. [ABSTRACT FROM AUTHOR]

Fracture healing is a complex staged repair process in which the mechanical environment plays a key role. Bone tissue is very sensitive to mechanical stress stimuli, and the literature suggests that appropriate stress can promote fracture healing by altering cellular function. However, fracture healing is a coupled process involving multiple cell types that balance and limit each other to ensure proper fracture healing. The main cells that function during different stages of fracture healing are different, and the types and molecular mechanisms of stress required are also different. Most previous studies have used a single mechanical stimulus on individual mechanosensitive cells, and there is no relatively uniform standard for the size and frequency of the mechanical stress. Analyzing the mechanisms underlying the effects of mechanical stimulation on the metabolic regulation of signaling pathways in cells such as in bone marrow mesenchymal stem cells (BMSCs), osteoblasts, chondrocytes, and osteoclasts is currently a challenging research hotspot. Grasping how stress affects the function of different cells at the molecular biology level can contribute to the refined management of fracture healing. Therefore, in this review, we summarize the relevant literature and describe the effects of mechanical stress on cells associated with fracture healing, and their possible signaling pathways, for the treatment of fractures and the further development of regenerative medicine. [ABSTRACT FROM AUTHOR]

Osteochondral lesions of the talus are common in patients suffering even minor trauma; timely diagnosis and treatment can prevent the development of early osteoarthritis. The objectives of this systematic review and meta-analysis were to evaluate the effects of additional procedures on arthroscopic ankle microperforations for osteochondral lesions. A systematic literature search was conducted using PubMed-Medline, Cochrane Central, and Google Scholar to select clinical studies analyzing the efficacy of platelet-rich plasma (PRP), hyaluronic acid (HA), and bone marrow concentrate (BMC) procedures. Ten articles following PRISMA guidelines with a total of 464 patients were included in this review. Quality assessment using MINORS was performed, and all studies demonstrated high quality. The results of the systematic review showed benefits in all patients undergoing infiltrative therapy with PRP, hyaluronic acid, and BMC. The best results in terms of AOFAS score and VAS scale were found in patients undergoing PRP injection. The meta-analysis showed improvements in pain relief and return to daily activities in patients undergoing arthroscopic microperforations and PRP, although not reporting statistically significant results (p = 0.42). All treatment strategies reported better scores compared to the control groups. Among the various treatments analyzed, the addition of PRP appears to be the most valuable probably for the larger population receiving this treatment, showing excellent outcomes in pain reduction, clinical outcomes, and return to daily activities. II [ABSTRACT FROM AUTHOR]