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Retinal neurovascular unit (NVU) is a multi-cellular structure that consists of the functional coupling between neural tissue and vascular system. Disrupted NVU will result in the occurrence of retinal and choroidal vascular diseases, which are characterized by the development of neovascularization, increased vascular permeability, and inflammation. This pathological entity mainly includes neovascular age-related macular degeneration (neovascular-AMD), diabetic retinopathy (DR) retinal vein occlusion (RVO), and retinopathy of prematurity (ROP). Emerging evidences suggest that the angopoietin/tyrosine kinase with immunoglobulin and epidermal growth factor homology domains (Ang/Tie) signaling pathway is essential for the development of retinal and choroidal vascular. Tie receptors and their downstream pathways play a key role in modulating the vascular development, vascular stability, remodeling and angiogenesis. Angiopoietin 1 (Ang1) is a natural agonist of Tie2 receptor, which can promote vascular stability. On the other hand, angiopoietin 2 (Ang2) is an antagonist of Tie2 receptor that causes vascular instability. Currently, agents targeting the Ang/Tie signaling pathway have been used to inhibit neovascularization and vascular leakage in neovascular-AMD and DR animal models. Particularly, the AKB-9778 and Faricimab have shown promising efficacy in improving visual acuity in patients with neovascular-AMD and DR. These experimental and clinical evidences suggest that activation of Ang/Tie signaling pathway can inhibit the vascular permeability, neovascularization, thereby maintaining the normal function and structure of NVU. This review seeks to introduce the versatile functions and elucidate the modulatory mechanisms of Ang/Tie signaling pathway. Recent pharmacologic therapies targeting this pathway are also elaborated and summarized. Further translation of these findings may afford a new therapeutic strategy from bench to bedside. [ABSTRACT FROM AUTHOR]

Background. Angiogenesis plays a crucial role in the progression of breast cancer. Identifying and investigating the key components of this process, focused on phenotype as well as microenvironment of the tumor, is considered highly relevant for understanding tumor biology. Studies into the expression of angiogenesis-related factors by means of immunohistochemical methods appear valuable for both assessing conventional chemotherapy options and identifying new targets in targeted therapy for breast cancer. Objectives. To investigate angiogenesis in breast ductal carcinoma by assessing the expression of vascular endothelial growth factor, angiopoietin-2, and hypoxia-inducible factor alpha in the context of various therapeutic strategies. Methods. An observational cohort study was conducted using biopsy samples from female patients with confirmed diagnoses of “fibroadenoma” and “ductal carcinoma of the breast,” residents of the Republic of Crimea, who applied to oncological hospitals in Simferopol from January 2021 to January 2023. Examination involved histological sections of breast tumor tissue from 68 patients with verified diagnoses of “ductal carcinoma” and “fibroadenoma” (the mean age of the patients was 65 ± 5). The following cohorts were formed in the study: control group, consisting of patients with breast fibroadenoma (n = 20); two subgroups of patients with ductal carcinoma of the breast (n = 48), including Group I — patients with ductal carcinoma of the breast who had not received chemotherapy (n = 23), Group II — patients with ductal carcinoma of the breast, who underwent surgery following one or more courses of chemotherapy (n = 25). The study involved examining the tumor tissue sections obtained from paraffin blocks, assessing the expression of angiogenesis markers via immunohistochemistry using primary antibodies against vascular endothelial growth factor, angiopoietin 2, and hypoxia-inducible factor alpha. Statistical analysis was carried out using Statistica 10.0 (StatSoft, USA). Differences were considered significant at error probability p ≤ 0.05. The value of p < 0.05 was deemed statistically significant for all types of analysis. Results. The expression of hypoxia-inducible and vascular growth factors differed significantly between both groups with breast ductal carcinoma as well as when compared to the control group. The hypoxia-inducible factor having cytoplasmic localization was detected in the control group with benign processes, whereas the nuclear expression was noted in the breast ductal carcinoma groups. Significant differences in the nuclear expression of hypoxia-inducible factor have been established among groups of patients with confirmed ductal carcinoma of the breast: in Group II, which underwent chemotherapy, expression was notably higher in both the tumor stroma and in the stroma of tumor-free areas. The hypoxia-inducible factor expression was significantly greater at the demarcation zone than that observed in samples from surgically treated women in Group I (p = 0.033; p = 0.034, p < 0.001, respectively). In the tumor epithelium of patients with breast ductal carcinoma, vascular endothelial growth factor was expressed significantly more intensively in the group who did not receive chemotherapy compared to the other group (p < 0.001). Conversely, in the tumor stroma, angiopoietin exhibited significantly higher expression levels among patients who underwent chemotherapy compared to those who received no treatment; this was observed in both the tumor areas due to endothelial cell involvement (p = 0.004) and in conditionally healthy regions of the breast (p < 0.001). In the control group represented by fibroadenoma patients, the expression of the studied factors is more pronounced than in the groups with ductal carcinoma of the breast. Conclusion. The obtained data indicate the activation of angiogenesis processes in the group of patients after chemotherapy, as evidenced by the increased expression of hypoxia-inducible factor, vascular endothelial growth factor, and angiopoietin. This result is associated with the high prevalence of resistant forms of breast ductal carcinoma in Group II. The study of the signaling pathways of angiogenesis and its components provides valuable insights into patterns of occurrence and strategies to overcome chemotherapy resistance in ductal carcinoma of the breast.

Abstract Retinal neurovascular unit (NVU) is a multi-cellular structure that consists of the functional coupling between neural tissue and vascular system. Disrupted NVU will result in the occurrence of retinal and choroidal vascular diseases, which are characterized by the development of neovascularization, increased vascular permeability, and inflammation. This pathological entity mainly includes neovascular age-related macular degeneration (neovascular-AMD), diabetic retinopathy (DR) retinal vein occlusion (RVO), and retinopathy of prematurity (ROP). Emerging evidences suggest that the angopoietin/tyrosine kinase with immunoglobulin and epidermal growth factor homology domains (Ang/Tie) signaling pathway is essential for the development of retinal and choroidal vascular. Tie receptors and their downstream pathways play a key role in modulating the vascular development, vascular stability, remodeling and angiogenesis. Angiopoietin 1 (Ang1) is a natural agonist of Tie2 receptor, which can promote vascular stability. On the other hand, angiopoietin 2 (Ang2) is an antagonist of Tie2 receptor that causes vascular instability. Currently, agents targeting the Ang/Tie signaling pathway have been used to inhibit neovascularization and vascular leakage in neovascular-AMD and DR animal models. Particularly, the AKB-9778 and Faricimab have shown promising efficacy in improving visual acuity in patients with neovascular-AMD and DR. These experimental and clinical evidences suggest that activation of Ang/Tie signaling pathway can inhibit the vascular permeability, neovascularization, thereby maintaining the normal function and structure of NVU. This review seeks to introduce the versatile functions and elucidate the modulatory mechanisms of Ang/Tie signaling pathway. Recent pharmacologic therapies targeting this pathway are also elaborated and summarized. Further translation of these findings may afford a new therapeutic strategy from bench to bedside.

Loss of the inner blood–retinal barrier (BRB) integrity is a main feature of ocular diseases such as diabetic macular edema. However, there is a lack of clarity on how inner BRB function is modulated within the diabetic retina. The current study examined whether eucalyptol inhibited inner BRB destruction and aberrant retinal angiogenesis in 33 mM glucose-exposed human retinal microvascular endothelial (RVE) cells and db/db mice. This study further examined the molecular mechanisms underlying endothelial dysfunction including retinal endoplasmic reticulum (ER) stress and angiopoietin (Ang)/Tie axis in conjunction with vascular endothelial growth factor (VEGF). Eucalyptol is a naturally occurring monoterpenoid and an achiral aromatic component of many plants including eucalyptus leaves. Nontoxic eucalyptol reduced the production of amyloid-β (Aβ) protein in glucose-loaded RVE cells and in diabetic mice. This natural compound blocked apoptosis of Aβ-exposed RVE cells in diabetic mouse eyes by targeting ER stress via the inhibition of PERK-eIF2α-ATF4-CHOP signaling. Eucalyptol promoted activation of the Ang-1/Tie-2 pathway and dual inhibition of Ang-2/VEGF in Aβ-exposed RVE cells and in diabetic eyes. Supply of eucalyptol reversed the induction of junction proteins in glucose/Aβ-exposed RVE cells within the retina and reduced permeability. In addition, oral administration of eucalyptol reduced vascular leaks in diabetic retinal vessels. Taken together, these findings clearly show that eucalyptol inhibits glucose-induced Aβ-mediated ER stress and manipulates Ang signaling in diabetic retinal vessels, which ultimately blocks abnormal angiogenesis and loss of inner BRB integrity. Therefore, eucalyptol provides new treatment strategies for diabetes-associated RVE defects through modulating diverse therapeutic targets including ER stress, Ang-1/Tie-2 signaling, and Ang-2/VEGF. [ABSTRACT FROM AUTHOR]

OBJECTIVE To evaluate the relationships between the severity of myxomatous mitral valve disease (MMVD) and pulmonary hypertension (PH) and serum angiopoietin (Ang)-1 and Ang-2 concentrations in dogs with MMVD. ANIMALS 74 dogs (control, n = 12; MMVD, n = 62) were included. METHODS Serum Ang-1 and Ang-2 concentrations were estimated using the canine-specific ELISA kit. The concentrations were compared between dogs with MMVD and healthy dogs, and they were analyzed according to the severity of MMVD and PH. RESULTS The median serum Ang-1 concentration did not differ among the study groups. The median serum Ang-2 concentration was higher in dogs with stage B2 MMVD (P = .041) and acute congestive heart failure (P = .002) than in control dogs. In addition, the median serum Ang-2 concentration was higher in MMVD dogs with PH than in those without PH (P = .031). Serum Ang-2 concentration was correlated with vertebral heart score (rs = 0.36, P = .004) and vertebral left atrial score (r = 0.50, P < .001) in dogs with MMVD, and correlated with vertebral heart score (r = 0.63, P = .01), maximum E wave amplitude of the diastolic transmitral flow (rs = 0.61, P = .018), ejection fraction (rs = -0.77, P < .001) and fractional shortening (rs = -0.56, P = .032) in dogs with acute congestive heart failure. CLINICAL RELEVANCE Circulating Ang-2 levels increase in dogs with the severity of MMVD and the presence of PH. [ABSTRACT FROM AUTHOR]

Introduction: Renal injury is among the leading causes of morbidity and mortality; however, there are no reliable indicators for determining the likelihood of developing chronic kidney disease (CKD), CKD progression, or AKI events. Vascular growth factors called angiopoietins have a role in endothelial function, vascular remodeling, tissue stabilization, and inflammation and have been implicated as prognostic and predictive markers in AKI. Methods: Although the exact mechanism of the relationship between kidney injury and angiopoietins is unknown, this review demonstrates that AKI patients have higher angiopoietin-2 levels and that higher angiopoietin-1 to angiopoietin-2 ratio may potentially be linked with a reduced risk of the CKD progression. Results: This review therefore emphasizes the importance of angiopoietin-2 and proposes that it could be an important predictor of AKI in clinical settings. Conclusion: There is a need for further large-scale randomized clinical trials in order to have a better understanding of the significance of angiopoietin-2 and for the determination of its potential clinical implications. [ABSTRACT FROM AUTHOR]

The activation of the angiopoietin (Angpt)-Tie system is linked to endothelial dysfunction during sepsis. Bacterial quorum-sensing molecules function as pathogen-associated molecular patterns. However, their impact on the endothelium and the Angpt-Tie system remains unclear. Therefore, this study investigated whether treatment with N-3-oxododecanoyl homoserine lactone (3OC12-HSL), a quorum-sensing molecule derived from Pseudomonas aeruginosa, impaired endothelial function in human umbilical vein endothelial cells. 3OC12-HSL treatment impaired tube formation even at sublethal concentrations, and immunocytochemistry analysis revealed that it seemed to reduce vascular endothelial-cadherin expression at the cell−cell interface. Upon assessing the mRNA expression patterns of genes associated with the Angpt-Tie axis, the expressions of Angpt2, Forkhead box protein O1, Tie1, and vascular endothelial growth factor 2 were found to be upregulated in the 3OC12-HSL-treated cells. Moreover, western blot analysis revealed that 3OC12-HSL treatment increased Angpt2 expression. A co-immunoprecipitation assay was conducted to assess the effect of 3OC12-HSL on the IQ motif containing GTPase activating protein 1 (IQGAP1) and Rac1 complex and the interaction between these proteins was consistently maintained regardless of 3OC12-HSL treatment. Next, recombinant human (rh)-Angpt1 was added to assess whether it modulated the effects of 3OC12-HSL treatment. rh-Angpt1 addition increased cellular viability, improved endothelial function, and reversed the overall patterns of mRNA and protein expression in endothelial cells treated with 3OC12-HSL. Additionally, it was related to the increased expression of phospho-Akt and the IQGAP1 and Rac1 complex. Collectively, our findings indicated that 3OC12-HSL from Pseudomonas aeruginosa can impair endothelial integrity via the activation of the Angpt-Tie axis, which appeared to be reversed by rh-Angpt1 treatment. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause potentially life-threatening coronavirus disease (COVID-19). COVID-19 is a multisystem disease and is associated with significant respiratory distress, systemic hyperinflammation, vasculitis, and multi-organ failure. SARS-CoV-2 causes the deterioration of numerous systems, with increasing evidence implying that COVID-19 affects the endothelium and vascular function. The endothelium is important for preserving vascular tone and homeostasis. The overactivation and dysfunction of endothelial cells are significant outcomes of severity in patients with COVID-19. The Angiopoietin 1/Tie 2 pathway plays an important role in endothelium quiescence and vessel stability. The disruption of Angiopoietin/Tie balance affects the vessel contact barrier and leads to vessel leakage, and this in turn causes endothelial dysfunction. Although vascular instability through SARS-CoV-2 is associated with endothelial dysfunction, it is still not understood if the virus affects the Angiopoietin/Tie axis directly or via other mechanisms such as cytokine storm and/or immune response associated with the infection. This review provides an overview of the impact SARS-CoV-2 has on endothelial function and more specifically on the Angiopoietin/Tie pathway.

Tumor angiogenesis, the formation of new blood vessels within the tumor microenvironment, is considered a hallmark of cancer progression and represents a crucial target for therapeutic intervention. The tumor microenvironment is characterized by a complex interplay between proangiogenic and antiangiogenic factors, regulating the vascularization necessary for tumor growth and metastasis. The study of angiogenesis involves a spectrum of techniques, spanning from biomarker assessment to advanced imaging modalities. This comprehensive review aims to provide insights into the molecular intricacies, regulatory dynamics, and clinical implications of tumor angiogenesis. By delving into these aspects, we gain a deeper understanding of the processes driving vascularization in tumors, paving the way for the development of novel and effective antiangiogenic therapies in the fight against cancer. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause potentially life-threatening coronavirus disease (COVID-19). COVID-19 is a multisystem disease and is associated with significant respiratory distress, systemic hyperinflammation, vasculitis, and multi-organ failure. SARS-CoV-2 causes the deterioration of numerous systems, with increasing evidence implying that COVID-19 affects the endothelium and vascular function. The endothelium is important for preserving vascular tone and homeostasis. The overactivation and dysfunction of endothelial cells are significant outcomes of severity in patients with COVID-19. The Angiopoietin 1/Tie 2 pathway plays an important role in endothelium quiescence and vessel stability. The disruption of Angiopoietin/Tie balance affects the vessel contact barrier and leads to vessel leakage, and this in turn causes endothelial dysfunction. Although vascular instability through SARS-CoV-2 is associated with endothelial dysfunction, it is still not understood if the virus affects the Angiopoietin/Tie axis directly or via other mechanisms such as cytokine storm and/or immune response associated with the infection. This review provides an overview of the impact SARS-CoV-2 has on endothelial function and more specifically on the Angiopoietin/Tie pathway. [ABSTRACT FROM AUTHOR]

• Despite potent antimalarials, mortality of pediatric severe malaria (SM) remains high. • There is no adjunctive therapies to improve clinical outcomes of SM. • Rosiglitazone acts on several pathways in the pathogenesis of severe malaria. • Rosiglitazone as adjunctive therapy is safe and well-tolerated in children. • Efficacy of rosiglitazone must be further evaluated in larger clinical trials. We tested the hypothesis that adjunctive rosiglitazone treatment would reduce levels of circulating angiopoietin-2 (Angpt-2) and improve outcomes of Mozambican children with severe malaria. A randomized, double-blind, placebo-controlled trial of rosiglitazone vs placebo as adjunctive treatment to artesunate in children with severe malaria was conducted. A 0.045 mg/kg/dose of rosiglitazone or matching placebo were administered, in addition to standard of malaria care, twice a day for 4 days. The primary endpoint was the rate of decline of Angpt-2 over 96 hours. Secondary outcomes included the longitudinal dynamics of angiopoietin-1 (Angpt-1) and the Angpt-2/Angpt-1 ratio over 96 hours, parasite clearance kinetics, clinical outcomes, and safety metrics. Overall, 180 children were enrolled; 91 were assigned to rosiglitazone and 89 to placebo. Children who received rosiglitazone had a steeper rate of decline of Angpt-2 over the first 96 hours of hospitalization compared to children who received placebo; however, the trend was not significant (P = 0.28). A similar non-significant trend was observed for Angpt-1 (P = 0.65) and the Angpt-2/Angpt-1 ratio (P = 0.34). All other secondary and safety outcomes were similar between groups (P >0.05). Adjunctive rosiglitazone at this dosage was safe and well tolerated but did not significantly affect the longitudinal kinetics of circulating Angpt-2. [ABSTRACT FROM AUTHOR]

Background: We assessed the relationship between sepsis occurrence and the serum levels of angiopoietin (Ang-1, Ang-2), vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) in pediatric patients with cancer-related febrile neutropenia. Methods: Fifty-two children with malignant tumors who experienced 86 episodes of febrile neutropenia (FN) were examined between June 2016 and June 2018. Each FN episode was considered a separate event and the total number of FNs were recorded (86 FN episodes = FN group). The control group consisted of 21 healthy children. Ang-1, Ang-2, VEGF-A and sFlt-1 were measured at the baseline and 48th hour of each FN episode -alongside routine characterization of inflammation (C-reactive protein; white blood cell and absolute neutrophil count). Results: Among the episodes, 29 (34.5%) developed sepsis while 57 were classified as non-complicated FN. The baseline values of patients and controls were significantly different for Ang-1, Ang-2, VEGF and sFlt-1 values (all, p < 0.05). In the subgroup with sepsis, Ang-2 values were higher than in the subgroup without sepsis (p = 0.017). In predicting sepsis, Ang-2 had 60.7% sensitivity and 66.7% specificity at the 74.6 cut-off value (AUC: 0.662 [95%CI: 0.541 - 0.783], p = 0.022), Ang-2 / Ang-1 ratio had 65.5% sensitivity and 60.0% specificity at the 0.405 cut-off value (AUC: 0.633 [95%CI: 0.513 - 0.753], p = 0.046). Conclusions. Our results reveal that Ang-2 and Ang-2/Ang-1 were higher in the sepsis group and Ang-2 might be a biomarker to indicate the risk of sepsis in patients with FN and/or cancer. [ABSTRACT FROM AUTHOR]

The viral agent SARS-CoV-2 clearly affects several organ systems, including the cardiovascular system. Angiopoietins are involved in vascular integrity and angiogenesis. Angiopoietin-1 (Ang1) promotes vessel stabilization, while angiopoietin-2 (Ang2), which is usually expressed at low levels, is significantly elevated in inflammatory and angiogenic conditions. Interleukin-6 (IL-6) is known to induce defective angiogenesis via the activation of the Ang2 pathway. Vasculitis and vasculopathy are some of the defining features of moderate to severe COVID-19-associated systemic disease. We investigated the serum levels of angiopoietins, as well as interleukin-6 levels and anti-SARS-CoV2 IgG titers, in hospitalized COVID-19 patients across disease severity and healthy controls. Ang2 levels were elevated in COVID-19 patients across all severity compared to healthy controls, while Ang1 levels were decreased. The patients with adverse outcomes (death and/or prolonged hospitalization) had relatively lower and stable Ang1 levels but continuously elevated Ang2 levels, while those who had no adverse outcomes had increasing levels of both Ang1 and Ang2, followed by a decrease in both. These results suggest that the dynamic levels of Ang1 and Ang2 during the clinical course may predict adverse outcomes in COVID-19 patients. Ang1 seems to play an important role in controlling Ang2-related inflammatory mechanisms in COVID-19 patients. IL-6 and anti-SARS-CoV2 spike protein IgG levels were significantly elevated in patients with severe disease. Our findings represent an informative pilot assessment into the role of the angiopoietin signaling pathway in the inflammatory response in COVID-19. [ABSTRACT FROM AUTHOR]

Coagulation activation in immunothrombosis involves various pathways distinct from classical hemostasis, offering potential therapeutic targets to control inflammation-induced hypercoagulability while potentially sparing hemostasis. The Angiopoietin/Tie2 pathway, previously linked to embryonic angiogenesis and sepsis-related endothelial barrier regulation, was recently associated with coagulation activation in sepsis and COVID-19. This study explores the connection between key mediators of the Angiopoietin/Tie2 pathway and coagulation activation. The study included COVID-19 patients with hypoxia and healthy controls. Blood samples were processed to obtain platelet-free plasma, and frozen until analysis. Extracellular vesicles (EVs) in plasma were characterized and quantified using flow cytometry, and their tissue factor (TF) procoagulant activity was measured using a kinetic chromogenic method. Several markers of hemostasis were assessed. Levels of ANGPT1, ANGPT2, and soluble Tie2 correlated with markers of coagulation and platelet activation. EVs from platelets and endothelial cells were increased in COVID-19 patients, and a significant increase in TF+ EVs derived from endothelial cells was observed. In addition, ANGPT2 levels were associated with TF expression and activity in EVs. In conclusion, we provide further evidence for the involvement of the Angiopoietin/Tie2 pathway in the coagulopathy of COVID-19 mediated in part by release of EVs as a potential source of TF activity.

Loss of the inner blood–retinal barrier (BRB) integrity is a main feature of ocular diseases such as diabetic macular edema. However, there is a lack of clarity on how inner BRB function is modulated within the diabetic retina. The current study examined whether eucalyptol inhibited inner BRB destruction and aberrant retinal angiogenesis in 33 mM glucose-exposed human retinal microvascular endothelial (RVE) cells and db/db mice. This study further examined the molecular mechanisms underlying endothelial dysfunction including retinal endoplasmic reticulum (ER) stress and angiopoietin (Ang)/Tie axis in conjunction with vascular endothelial growth factor (VEGF). Eucalyptol is a naturally occurring monoterpenoid and an achiral aromatic component of many plants including eucalyptus leaves. Nontoxic eucalyptol reduced the production of amyloid-β (Aβ) protein in glucose-loaded RVE cells and in diabetic mice. This natural compound blocked apoptosis of Aβ-exposed RVE cells in diabetic mouse eyes by targeting ER stress via the inhibition of PERK-eIF2α-ATF4-CHOP signaling. Eucalyptol promoted activation of the Ang-1/Tie-2 pathway and dual inhibition of Ang-2/VEGF in Aβ-exposed RVE cells and in diabetic eyes. Supply of eucalyptol reversed the induction of junction proteins in glucose/Aβ-exposed RVE cells within the retina and reduced permeability. In addition, oral administration of eucalyptol reduced vascular leaks in diabetic retinal vessels. Taken together, these findings clearly show that eucalyptol inhibits glucose-induced Aβ-mediated ER stress and manipulates Ang signaling in diabetic retinal vessels, which ultimately blocks abnormal angiogenesis and loss of inner BRB integrity. Therefore, eucalyptol provides new treatment strategies for diabetes-associated RVE defects through modulating diverse therapeutic targets including ER stress, Ang-1/Tie-2 signaling, and Ang-2/VEGF.

In Duchenne muscular dystrophy (DMD), angiogenesis appears to be attenuated. Local administration of angiopoietin 1 (Ang1) has been shown to reduce inflammation, ischemia, and fibrosis in DMD mice. Ang1 is a vital vascular stabilizing factor that activates the endothelial cell receptor Tie2, leading to downstream pro-survival PI3K/Akt pathway activation and eNOS phosphorylation. In this study, we aimed to characterize the Ang/Tie2 signaling pathway within the diaphragm muscle of mouse models of DMD. Utilizing ELISA, immunoblots, and RT-qPCR, we demonstrated that Ang1 was downregulated, while the antagonist angiopoietin 2 (Ang2) was upregulated, leading to a decreased Ang1/Ang2 ratio. This correlated with a reduction in the phosphorylated Tie2/total Tie2 ratio. Interestingly, no significant differences in Akt or eNOS phosphorylation were observed, although DMD murine models did have elevated total Akt protein concentrations. These observations suggest that Ang1/Tie2 signaling may be dysregulated in the diaphragm muscle of DMD and further investigations may lead to new therapeutic interventions for DMD. [ABSTRACT FROM AUTHOR]

Proper vascular formation is regulated by multiple signaling pathways. The vascular endothelial growth factor (VEGF) signaling promotes endothelial proliferation. Notch and its downstream targets act to lead endothelial cells toward an arterial fate through regulation of arterial gene expression. However, the mechanisms of how endothelial cells (ECs) in the artery maintain their arterial characteristics remain unclear. Here, we show that PRDM16 (positive regulatory domain-containing protein 16), a zinc finger transcription factor, is expressed in arterial ECs, but not venous ECs in developing embryos and neonatal retinas. Endothelial-specific deletion of Prdm16 induced ectopic venous marker expression in the arterial ECs and reduced vascular smooth muscle cell (vSMC) recruitment around arteries. Whole-genome transcriptome analysis using isolated brain ECs show that the expression of Angpt2 (encoding ANGIOPOIETIN2, which inhibits vSMC recruitment) is upregulated in the Prdm16 knockout ECs. Conversely, forced expression of PRDM16 in venous ECs is sufficient to induce arterial gene expression and repress the ANGPT2 level. Together, these results reveal an arterial cell-autonomous function for PRDM16 in suppressing venous characteristics in arterial ECs. [ABSTRACT FROM AUTHOR]

Objectives Angiogenesis occurs during tumor progression of hepatocellular carcinoma (HCC) after insufficient radiofrequency ablation (RFA). Arsenic trioxide (ATO) shows promising therapeutic potential in advanced HCC. Whether ATO regulates angiogenesis and can be used to prevent tumor progression in HCC after insufficient RFA is still unknown.Methods Insufficient RFA was simulated using a water bath. MTT assay and tube formation assay were used to evaluate the effects of ATO on viability and proangiogenic abilities of SMMC7721 and HepG2 cells after insufficient RFA in vitro. The molecular changes with the treatment of ATO were evaluated through Western blot. An ectopic nude mice model was used to evaluate the effect of ATO on the tumor of SMMC7721 cells in vivo after insufficient RFA.Results In this study, HepG2 and SMMC7721 cells after insufficient RFA (named HepG2-H and SMMC7721-H, respectively) showed higher proliferation than the untreated cells and promoted tube formation of endothelial cells in a paracrine manner. ATO eliminated the difference in proliferation between untreated and RFA-treated cells and suppressed angiogenesis induced by HCC cells after insufficient RFA through the Ang-1 (angiopoietin-1)/Ang-2 (angiopoietin-2)/Tie2 pathway. Hif-1α overexpression abolished the inhibitory effect of ATO on angiogenesis in HCC after insufficient RFA. ATO inhibited tumor growth and angiogenesis in HCC after insufficient RFA.Conclusions Our results demonstrate that ATO blocks the paracrine signaling of Ang-1 and Ang-2 by inhibiting p-Akt/Hif-1α and further suppresses the angiogenesis of HCC after insufficient RFA.

Abstract Background A previous study found that circulating angiopoietin-1 (angpt-1) concentrations were significantly lower in patients who had a recent ischaemic stroke compared to healthy controls. The primary aim of this study was to assess whether serum angpt-1 could be used as a diagnostic test of ischemic stroke in patients presenting to hospital as an emergency. Exploratory analyses investigated the association of proteins functionally related to angpt-1 (angpt-2, Tie-2, matrix metalloproteinase-9 and vascular endothelial growth factors A, C and D) with ischaemic stroke diagnosis. Methods Patients presenting to Townsville University Hospital for emergency assessment of stroke-like symptoms were consecutively recruited and provided a blood sample. After assessment by a consultant neurologist, patients were grouped into those who did, or did not have ischaemic stroke. The potential for serum angpt-1 to diagnose ischaemic stroke was assessed using receiver operator characteristic (ROC) curves. Cross-sectional analyses appraised inter-group differences in the serum concentration of other proteins. Results One-hundred and twenty-six patients presenting to Townsville University Hospital for emergency assessment of stroke-like symptoms were recruited (median time from symptom onset to hospital presentation: 2.6 (inter-quartile range: 1.2–4.6) hours). Serum angpt-1 had poor ability to diagnose ischaemic stroke in analyses using the whole cohort, or in sensitivity analyses (area under the ROC curve 0.51 (95% CI: 0.41–0.62) and 0.52 (95% CI: 0.39–0.64), respectively). No associations of serum angpt-1 concentration with ischaemic stroke severity, symptom duration or aetiology were observed. Serum concentrations of the other assessed proteins did not differ between patient groups. Conclusions Serum angpt-1 concentration is unlikely to be useful for emergency diagnosis of ischaemic stroke.

Purpose: To determine the correlation of angiogenic growth factors and inflammatory cytokines with the clinical phenotype of ocular tuberculosis (OTB). Methods: Vitreous fluid was analysed for cytokines in patients with OTB and non-OTB uveitis using multiplex fluorescent bead-based flow cytometric assay. The clinical phenotypes were recorded and correlated with vitreous biomarkers. Results: Vitreous humour from OTB patients had elevated levels of interleukin-10 (IL-10), IL-17-A, interferon-gamma (IFN-γ), and tumour necrosis factor-alpha (TNF-α). Angiopoietin (Ang-2) levels were higher in the panuveitis phenotype. OTB posterior uveitis phenotype had relatively higher vascular endothelial growth factor (VEGF) levels and lower fibroblast growth factor (FGF) levels. Additionally, eyes with choroiditis and vasculitis had elevated levels of VEGF and Ang-2 with FGF downregulation. Both IFN-γ and IL-10 were upregulated in the choroiditis phenotype of OTB. Conclusion: Angiogenic growth factors and inflammatory cytokines were altered in the vitreous humour of OTB patients. IFN-γ, VEGF, and IL-10 levels are increased in choroiditis and vasculitis phenotypes. Receiver operating characteristic (ROC) curve analysis further emphasized the importance of the IFN-γ assay in the diagnosis of OTB. [ABSTRACT FROM AUTHOR]

Purpose: The immune environment represents a new, but little explored, tool for understanding neuroendocrine neoplasms (NENs) behavior. An immunosuppressed microenvironment is hypothesized to promote NENs progression. A missing profiling of circulating leukocyte and peripheral blood mononuclear cells (PBMCs) subpopulations would open new perspectives in the still limited diagnostic-therapeutic management of NENs. Methods: A cross-sectional case-control pilot study was performed recruiting 30 consecutive subjects: 15 patients naïve to treatment, with histologically proven gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) and 15 healthy controls, matched for age and sex. PBMCs subpopulations were studied by flow cytometry. Soluble Tie2 (sTie2), Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2) were evaluated by ELISA. Results: Immune cell profiling revealed a significant lower CD3−CD56+ natural killer (NK) cell count in NETs vs controls (p = 0.04). NK subset analysis showed a reduced relative count of CD56+CD16+ NK cells (p =0.002) in NETs vs controls. Patients with NET showed a higher percentage of CD14+CD16++ non-classical monocytes (p = 0.01), and a lower percentage of CD14+CD16+ intermediate monocytes (p = 0.04). A decrease in percentage (p = 0.004) of CD4+ T-helper lymphocytes was found in NET patients. Evaluation of cellular and serum angiopoietin pathway mediators revealed in NET patients a higher relative count of Tie2-expressing monocytes (TEMs) (p < 0.001), and high levels of Ang-1 (p = 0.003) and Ang-2 (p = 0.002). Conclusions: Patients with GEP-NET presented an immunosuppressed environment characterized by a low count of cytotoxic NK cells, a high count of anti-inflammatory non-classical monocytes, and a low count of T-helper lymphocytes. Higher levels of TEMs and angiopoietins suggest a crosstalk between innate immunity and angiogenic pathways in NETs. [ABSTRACT FROM AUTHOR]

The angiogenesis efficacy in solid tumors and hematological malignancies has been identified for more than twenty years. Although the exact role of angiogenesis in leukemia as a common hematological malignancy has not yet been extensively studied, its effect is demonstrated on the initiation and maintenance of a favorable microenvironment for leukemia cell proliferation. The angiopoietin family is a defined molecular mediator for angiogenesis, which contributes to vascular permeability and angiogenesis initiation. They participate in the angiogenesis process by binding to tyrosine kinase receptors (Tie) on endothelial cells. Considering the role of angiogenesis in leukemia development and the crucial effects of the Ang–Tie system in angiogenesis regulation, many studies have focused on the correlation between the Ang–Tie system and leukemia diagnosis, monitoring, and treatment. In this study, we reviewed the Ang–Tie system's potential diagnostic and therapeutic effects in different types of leukemia in the gene expression level analysis approach. The angiopoietin family context-dependent manner prevents us from defining its actual function in leukemia, emphasizing the need for more comprehensive studies. [ABSTRACT FROM AUTHOR]

Background and Objectives: Faricimab is a novel bispecific antibody with Fab regions inhibiting both vascular endothelial growth factor-A and angiopoietin-2. Therefore, this study aimed to obtain short-term outcomes of intravitreal injection of faricimab (IVF) for the treatment of diabetic macular edema (DME) in daily clinical practice. Materials and Methods: A retrospective review was carried out on consecutive patients with DME who had been treated with IVF and were followed up for at least 1 month. Outcome measures included changes in logMAR best-corrected visual acuity (logMAR BCVA), central retinal thickness (CRT), number of IVF administrations, and safety. Clinical outcomes were also compared between the treatment-naïve and switch groups. Results: A total of 21 consecutive DME eyes from 19 patients were identified. The mean number of IVFs was 1.6 ± 0.8 during the mean follow-up time of 5.5 months. The overall mean logMAR BCVA following IVF was 0.236, 0.204, 0.190, and 0.224 at baseline, 1, 3, and 6 months, respectively, without a significant change from baseline to 1 month (p = 0.176) or for 6 months (p = 0.923). The overall mean CRT (μm) following IVF was 400.6, 346.6, 342.1, and 327.5 at baseline, 1, 3, and 6 months, respectively. CRT significantly decreased from baseline to 1 month (p = 0.001) but did not reach a significant level over 6 months following IVF (p = 0.070). No significant difference in BCVA or CRT was observed between the treatment-naïve and switch groups. No serious safety concerns were noted. Conclusions: IVF for the treatment of DME may preserve visual acuity and improve macular thickness without serious safety concerns in the short term in a real-world clinical setting. [ABSTRACT FROM AUTHOR]

Placental growth factor (PlGF) and Angiopoietin (Ang)-1 are two proteins that are involved in the regulation of endothelial cell (EC) growth and vasculature formation. In the retina and endothelial cells, pericytes are the major source of both molecules. The purpose of this study is to examine the association of PlGF and Ang-1 with human EC/pericyte co-cultures and iPSC-derived vascular organoids. In this study, we used co-cultures of human primary retinal endothelial cells (HREC) and primary human retinal pericytes (HRP), western blotting, immunofluorescent analysis, TUNEL staining, LDH-assays, and RNA seq analysis, as well as human-induced pluripotent stem cells (iPSC), derived organoids (VO) to study the association between PlGF and Ang-1. Inhibition of PlGF by PlGF neutralizing antibody in HREC-HRP co-cultures resulted in the increased expression of Ang-1 and Tie-2 in a dose-dependent manner. This upregulation was not observed in HREC and HRP monocultures but only in co-cultures suggesting the association of pericytes and endothelial cells. Furthermore, Vascular endothelial growth factor receptor 1 (VEGFR1) inhibition abolished the Ang-1 and Tie-2 upregulation by PlGF inhibition. The pericyte viability in high-glucose conditions was also reduced by VEGFR1 neutralization. Immunofluorescent analysis showed that Ang-1 and Ang-2 were expressed mainly by perivascular cells in the VO. RNA seq analysis of the RNA isolated from VO in high glucose conditions indicated increased PlGF and Ang-2 expressions in the VO. PlGF inhibition increased the expression of Ang-1 and Tie-2 in VO, increasing the pericyte coverage of the VO microvascular network. Combined, these results suggest PlGF's role in the regulation of Ang-1 and Tie-2 expression through VEGFR1. These findings provide new insights into the neovascularization process in diabetic retinopathy and new targets for potential therapeutic intervention. [ABSTRACT FROM AUTHOR]

Proper vascular formation is regulated by multiple signaling pathways. The vascular endothelial growth factor (VEGF) signaling promotes endothelial proliferation. Notch and its downstream targets act to lead endothelial cells toward an arterial fate through regulation of arterial gene expression. However, the mechanisms of how endothelial cells (ECs) in the artery maintain their arterial characteristics remain unclear. Here, we show that PRDM16 (positive regulatory domain-containing protein 16), a zinc finger transcription factor, is expressed in arterial ECs, but not venous ECs in developing embryos and neonatal retinas. Endothelial-specific deletion of Prdm16 induced ectopic venous marker expression in the arterial ECs and reduced vascular smooth muscle cell (vSMC) recruitment around arteries. Whole-genome transcriptome analysis using isolated brain ECs show that the expression of Angpt2 (encoding ANGIOPOIETIN2, which inhibits vSMC recruitment) is upregulated in the Prdm16 knockout ECs. Conversely, forced expression of PRDM16 in venous ECs is sufficient to induce arterial gene expression and repress the ANGPT2 level. Together, these results reveal an arterial cell-autonomous function for PRDM16 in suppressing venous characteristics in arterial ECs.

Background: The aim of this study was to investigate whether the presence of benign or malignant nodular thyroid disease affects levels of circulating angiogenesis cytokines. Methods: In this study we investigated levels of angiopoietin – 1 and -2 (Ang-1 and Ang-2 respectively), vascular endothelial growth factor –A (VEGF-A), galectin-3 (Gal-3), urokinase plasminogen activator receptor (uPAR) and plasminogen activation inhibitor – 1 (PAI-1) in 40 patients with differentiated thyroid cancer (DTC), 45 with thyroid papillary microcarcinoma (mPTC), 53 patients with multinodular goiter (MNG) and 58 controls. Six months after surgery 28 patients resubmitted blood samples. The diagnostic value of Ang-1 levels was evaluated with receiver operating characteristic (ROC) curves. Results: Statistically significant lower levels of Ang-1 were observed in DTC and MNG patients compared to controls (p

The viral agent SARS-CoV-2 clearly affects several organ systems, including the cardiovascular system. Angiopoietins are involved in vascular integrity and angiogenesis. Angiopoietin-1 (Ang1) promotes vessel stabilization, while angiopoietin-2 (Ang2), which is usually expressed at low levels, is significantly elevated in inflammatory and angiogenic conditions. Interleukin-6 (IL-6) is known to induce defective angiogenesis via the activation of the Ang2 pathway. Vasculitis and vasculopathy are some of the defining features of moderate to severe COVID-19-associated systemic disease. We investigated the serum levels of angiopoietins, as well as interleukin-6 levels and anti-SARS-CoV2 IgG titers, in hospitalized COVID-19 patients across disease severity and healthy controls. Ang2 levels were elevated in COVID-19 patients across all severity compared to healthy controls, while Ang1 levels were decreased. The patients with adverse outcomes (death and/or prolonged hospitalization) had relatively lower and stable Ang1 levels but continuously elevated Ang2 levels, while those who had no adverse outcomes had increasing levels of both Ang1 and Ang2, followed by a decrease in both. These results suggest that the dynamic levels of Ang1 and Ang2 during the clinical course may predict adverse outcomes in COVID-19 patients. Ang1 seems to play an important role in controlling Ang2-related inflammatory mechanisms in COVID-19 patients. IL-6 and anti-SARS-CoV2 spike protein IgG levels were significantly elevated in patients with severe disease. Our findings represent an informative pilot assessment into the role of the angiopoietin signaling pathway in the inflammatory response in COVID-19.

Endothelial barrier (EB) disruption contributes to acute lung injury in COVID-19, and levels of both VEGF-A and Ang-2, which are mediators of EB integrity, have been associated with COVID-19 severity. Here we explored the participation of additional mediators of barrier integrity in this process, as well as the potential of serum from COVID-19 patients to induce EB disruption in cell monolayers. In a cohort from a clinical trial consisting of thirty patients with COVID-19 that required hospital admission due to hypoxia we demonstrate that i) levels of soluble Tie2 were increase, and of soluble VE-cadherin were decreased when compared to healthy individuals; ii) sera from these patients induce barrier disruption in monolayers of endothelial cells; and iii) that the magnitude of this effect is proportional to disease severity and to circulating levels of VEGF-A and Ang-2. Our study confirms and extends previous findings on the pathogenesis of acute lung injury in COVID-19, reinforcing the concept that EB is a relevant component of this disease. Our results pave the way for future studies that can refine our understanding of the pathogenesis of acute lung injury in viral respiratory disorders, and contribute to the identification of new biomarkers and therapeutic targets for these conditions. [ABSTRACT FROM AUTHOR]

Cancer cells heavily utilise angiogenesis process to increase vascularisation for tumour mass growth and spread, so targeting this process is important to create an effective therapy. The AMHA1 strain of Newcastle disease virus (NDV) is an RNA virus with natural oncotropism. NDV induces direct tu-mour cytolysis, apoptosis, and immune stimulation. This work aimed to test NDV anti-angiogenic activity in a breast cancer model. To evaluate NDV’s antitumour effect in vivo, NDV was tested against mammary adenocarcinoma AN3 transplanted in syngeneic immunocompetent mice. In vivo antiangiogenic activity was evaluated by quantifying the blood vessels in treated and control tumour sections. In vitro experiments that exposed AMN3 mammary adenocarcinoma cells and Hep-2 laryn-geal carcinoma cells to NDV at different time intervals were performed to identify the exact mecha-nism of anti-angiogenesis by using angiogenesis microarray slides. In vivo results showed significant tumour regression and significant decrease in blood vessel formation in treated tumour sections. The in vitro microarray analysis of 14 different angiogenesis factors revealed that NDV downregulated angiopoietin-1, angiopoietin-2, and epidermal growth factor in mammary adenocarcinoma cells. However, NDV elicited a different effect on Hep-2 as represented by the downregulation of inducible protein 10, intracellular adhesion molecule-1, and basic fibroblast growth factor beta in NDV-infected tumour cells. It was found out that microarray analysis results helped interpret the in vivo data. The results suggested that the NDV oncolytic strain reduced angiogenesis by interfering with angiogenesis factors that might reduce tumour cell proliferation, infiltration, and invasion.

Objective: To investigate the effect of Moringa oleifera leaf extract on angiogenesis and inflammatory process in a rat model of streptozotocin-induced diabetic nephropathy. Methods: Four weeks after a single injection of 50 mg/kg streptozotocin, rats were treated with 100 or 200 mg/kg/day Moringa oleifera leaf extract, 1 mg/kg/day dapagliflozin, or a combination of Moringa oleifera leaf extract and dapagliflozin for further eight weeks. Renal function, kidney histology, and gene expression were evaluated at the end of the experiment. Results: Renal function of diabetic rats was significantly impaired as evidenced by increased blood urea nitrogen, albuminuria, 24-h proteinuria, and high creatinine clearance which indicated glomerular hyperfiltration. In addition, diabetic rats showed an increase in gene expressions of vascular endothelial growth factor-A (VEGF-A), angiopoietin-2 (Ang2), the Ang2/Ang1 ratio, tumor necrosis factor-α, interleukin-1β and monocyte chemoattractant protein-1. Immunohistochemical staining demonstrated a significant increase in the density of glycoprotein CD34. Moringa oleifera leaf extract markedly improved all renal dysfunction markers and modulated the upregulated expression of angiogenic factors and inflammatory genes. Conclusions: Moringa oleifera leaf extract could suppress abnormal angiogenesis and inflammatory processes possibly by downregulating gene expression of angiogenesis factors and proinflammatory cytokines.

Endothelial barrier (EB) disruption contributes to acute lung injury in COVID-19, and levels of both VEGF-A and Ang-2, which are mediators of EB integrity, have been associated with COVID-19 severity. Here we explored the participation of additional mediators of barrier integrity in this process, as well as the potential of serum from COVID-19 patients to induce EB disruption in cell monolayers. In a cohort from a clinical trial consisting of thirty patients with COVID-19 that required hospital admission due to hypoxia we demonstrate that i) levels of soluble Tie2 were increase, and of soluble VE-cadherin were decreased when compared to healthy individuals; ii) sera from these patients induce barrier disruption in monolayers of endothelial cells; and iii) that the magnitude of this effect is proportional to disease severity and to circulating levels of VEGF-A and Ang-2. Our study confirms and extends previous findings on the pathogenesis of acute lung injury in COVID-19, reinforcing the concept that EB is a relevant component of this disease. Our results pave the way for future studies that can refine our understanding of the pathogenesis of acute lung injury in viral respiratory disorders, and contribute to the identification of new biomarkers and therapeutic targets for these conditions.

Background: A previous study found that circulating angiopoietin-1 (angpt-1) concentrations were significantly lower in patients who had a recent ischaemic stroke compared to healthy controls. The primary aim of this study was to assess whether serum angpt-1 could be used as a diagnostic test of ischemic stroke in patients presenting to hospital as an emergency. Exploratory analyses investigated the association of proteins functionally related to angpt-1 (angpt-2, Tie-2, matrix metalloproteinase-9 and vascular endothelial growth factors A, C and D) with ischaemic stroke diagnosis.Methods: Patients presenting to Townsville University Hospital for emergency assessment of stroke-like symptoms were consecutively recruited and provided a blood sample. After assessment by a consultant neurologist, patients were grouped into those who did, or did not have ischaemic stroke. The potential for serum angpt-1 to diagnose ischaemic stroke was assessed using receiver operator characteristic (ROC) curves. Cross-sectional analyses appraised inter-group differences in the serum concentration of other proteins.Results: One-hundred and twenty-six patients presenting to Townsville University Hospital for emergency assessment of stroke-like symptoms were recruited (median time from symptom onset to hospital presentation: 2.6 (inter-quartile range: 1.2-4.6) hours). Serum angpt-1 had poor ability to diagnose ischaemic stroke in analyses using the whole cohort, or in sensitivity analyses (area under the ROC curve 0.51 (95% CI: 0.41-0.62) and 0.52 (95% CI: 0.39-0.64), respectively). No associations of serum angpt-1 concentration with ischaemic stroke severity, symptom duration or aetiology were observed. Serum concentrations of the other assessed proteins did not differ between patient groups.Conclusions: Serum angpt-1 concentration is unlikely to be useful for emergency diagnosis of ischaemic stroke. [ABSTRACT FROM AUTHOR]

Background and Hypothesis: Angiogenesis triggered by inflammation increases BBB permeability and facilitates macrophage transmigration. In the midbrain, we have discovered molecular alterations related to the blood-brain barrier (BBB), including endothelial cell changes associated with macrophage diapedesis, in neuroinflammatory schizophrenia and bipolar disorder, but changes in angiogenesis are yet to be reported. Hypothesis: We expected to discover molecular evidence of altered angiogenesis in the midbrain in individuals with schizophrenia and bipolar disorder compared to controls, with these changes more evident in "high" inflammation schizophrenia as compared to "low" inflammation., Study Design: In a case-control post-mortem cohort including schizophrenia (n = 35), bipolar disorder (n = 35), and controls (n = 33), we measured mRNA (RT-PCR) and protein (multiplex immunoassays) and performed immunohistochemistry to determine levels and anatomical distribution of angiogenesis-related molecules in the ventral midbrain., Study Results: We found large changes in angiogenesis factors in bipolar disorder high inflammatory subgroup (increased angiopoietin-2 and SERPINE1 mRNAs, but decreased angiopoietin-1, angiopoietin-2, and TEK receptor proteins). In schizophrenia high inflammatory subgroup, we found a robust increase in SERPINE1 mRNA and protein levels. However, we found no significant changes in angiopoietins in schizophrenia. We found that VEGFA mRNA level was increased in high inflammation schizophrenia, but only reached statistical significance compared to one low inflammatory subgroup., Conclusions: Thus, angiogenesis signaling pathways appeared to be involved in the BBB alterations when inflammation is also present in the midbrain of schizophrenia and bipolar disorder, with increased levels of SERPINE1 in schizophrenia high inflammatory subgroup and with a putative suppression of angiopoietin signaling in bipolar disorder high inflammatory subgroup., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Aziza Alrafiah,1 Ebtisam Alofi,2 Yasser Almohaya,1 Abdullah Hamami,1 Talal Qadah,1 Safa Almaghrabi,2 Nora Hakami,1 Moafaq S Alrawaili,3 Haythum O Tayeb3 1Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Physiology, Medical School, King Abdulaziz University, Jeddah, Saudi Arabia; 3Division of Neurology, Department of Internal Medicine, Faculty of Medicine, King AbdulAziz University, Jeddah, Saudi ArabiaCorrespondence: Aziza Alrafiah Tel +966 0126401000 Ext. 23495Email aalrafiah@kau.edu.saIntroduction: Stroke is a global health issue, and ischemic stroke is among the most common strokes affecting many people worldwide. Throughout ischemic stroke, various immune cells counter its effect by releasing cytokines, chemokines, and angiogenic molecules. These molecules can work as potential biomarkers in the diagnosis and monitoring of the progress of ischemic stroke. The current study investigated the use of angiogenic molecules as biomarkers in ischemic stroke patients.Methods: The samples were obtained from twenty healthy subjects and nineteen patients with ischemic stroke. Multiplex assay was used to measure the serum levels of angiogenic biomarkers, including endoglin, VEGF-A, endothelin-1, G-CSF, and angiopoietin-2. All data were analyzed using an unpaired Student’s t-test. Correlations between measured parameters were made using Pearson correlations.Results: Angiopoietin-2, VEGF-A, endothelin-1, and endoglin levels in stroke patients were significantly higher compared to healthy controls. Nevertheless, G-CSF level showed a non-significant increase in patients compared to controls. The correlation coefficient of measured angiogenic biomarkers among patients showed significant correlations between endoglin, angiopoietin, VEGF-A, and endothelin-1.Discussion: The angiogenic factors were significantly increased in patients with ischemic stroke, which may help in the early detection of ischemic stroke and consequently prompt treatment and better prognosis.Keywords: stroke, angiopoietin biomarkers, angiopoietin, endoglin, endothelin-1, VEGF-A

In Duchenne muscular dystrophy (DMD), angiogenesis appears to be attenuated. Local administration of angiopoietin 1 (Ang1) has been shown to reduce inflammation, ischemia, and fibrosis in DMD mice. Ang1 is a vital vascular stabilizing factor that activates the endothelial cell receptor Tie2, leading to downstream pro-survival PI3K/Akt pathway activation and eNOS phosphorylation. In this study, we aimed to characterize the Ang/Tie2 signaling pathway within the diaphragm muscle of mouse models of DMD. Utilizing ELISA, immunoblots, and RT-qPCR, we demonstrated that Ang1 was downregulated, while the antagonist angiopoietin 2 (Ang2) was upregulated, leading to a decreased Ang1/Ang2 ratio. This correlated with a reduction in the phosphorylated Tie2/total Tie2 ratio. Interestingly, no significant differences in Akt or eNOS phosphorylation were observed, although DMD murine models did have elevated total Akt protein concentrations. These observations suggest that Ang1/Tie2 signaling may be dysregulated in the diaphragm muscle of DMD and further investigations may lead to new therapeutic interventions for DMD.

Objective: To investigate the effect of Moringa oleifera leaf extract on angiogenesis and inflammatory process in a rat model of streptozotocin-induced diabetic nephropathy. Methods: Four weeks after a single injection of 50 mg/kg streptozotocin, rats were treated with 100 or 200 mg/kg/day Moringa oleifera leaf extract, 1 mg/kg/day dapagliflozin, or a combination of Moringa oleifera leaf extract and dapagliflozin for further eight weeks. Renal function, kidney histology, and gene expression were evaluated at the end of the experiment. Results: Renal function of diabetic rats was significantly impaired as evidenced by increased blood urea nitrogen, albuminuria, 24-h proteinuria, and high creatinine clearance which indicated glomerular hyperfiltration. In addition, diabetic rats showed an increase in gene expressions of vascular endothelial growth factor-A (VEGF-A), angiopoietin-2 (Ang2), the Ang2/Ang1 ratio, tumor necrosis factor-α, interleukin-1β and monocyte chemoattractant protein-1. Immunohistochemical staining demonstrated a significant increase in the density of glycoprotein CD34. Moringa oleifera leaf extract markedly improved all renal dysfunction markers and modulated the upregulated expression of angiogenic factors and inflammatory genes. Conclusions: Moringa oleifera leaf extract could suppress abnormal angiogenesis and inflammatory processes possibly by downregulating gene expression of angiogenesis factors and proinflammatory cytokines. [ABSTRACT FROM AUTHOR]

Objective: To determine whether serum angiopoietin-1/angiopoietin-2 ratio can predict preeclampsia in women at 16–18 weeks of gestation, or not. Material and Methods: This was a prospective observational study that was conducted in pregnant women with gestational age of 16-18 weeks. Serum angiopoietin-1 and angiopoietin-2 levels were acquired. The predictive values of these tests were calculated. Results: Data from 269 pregnant women were analyzed. Twenty-two cases developed preeclampsia, and five of these cases had early onset preeclampsia. When the angiopoietin-1/angiopoietin-2 ratio was above 6.2, the sensitivity, specificity, positive predictive value and negative predictive values to predict preeclampsia were 50.0%, 72.9%, 14.1% and 94.2%, respectively. When angiopoietin-1 was used to predict preeclampsia, the sensitivity, specificity, positive predictive value and negative predictive values were 59.1%, 65.2%, 13.1% and 94.7%, respectively. When angiopoietin-2 was used to predict preeclampsia, the sensitivity, specificity, positive predictive value and negative predictive values were 63.6%, 50.2%, 10.2% and 93.9%, respectively. Conclusion: This study demonstrated that serum angiopoietin-1/angiopoietin-2 ratio at 16-18 weeks of gestation was not effective in predicting preeclampsia. However, angiopoietin-2 may be used to predict preeclampsia.

Abstract Background Autologous fat grafting is often a crucial aspect of reconstructive and aesthetic surgeries, yet poor graft retention is a major issue with this technique. Enriching fat grafts with adipose tissue-derived mesenchymal stem cells (AD-MSCs) improves graft survival—however, AD-MSCs represent a heterogeneous population. Selection of subpopulations of AD-MSCs would allow the targeting of specific AD-MSCs that may benefit fat graft survival more than the general AD-MSC population. Methods Human AD-MSCs were selected for the surface marker CD271 using magnetic-activated cell sorting and compared to the CD271 negative phenotype. These subpopulations were analysed for gene expression using Real-Time qPCR and RNA sequencing; surface marker characteristics using immunostaining; ability to form tubules when cultured with endothelial cells; and gene and protein expression of key angiogenic mediators when cultured with ex-vivo adipose tissue. Results Human AD-MSCs with the surface marker CD271 express angiogenic genes at higher levels, and inflammatory genes at lower levels, than the CD271− AD-MSC population. A greater proportion of CD271+ AD-MSCs also possess the typical complement of stem cell surface markers and are more likely to promote effective neoangiogenesis, compared to CD271− AD-MSCs. Conclusion Enriching grafts with the CD271+ AD-MSC subpopulation holds potential for the improvement of reconstructive and aesthetic surgeries involving adipose tissue.

Background and Objectives: Faricimab is a novel bispecific antibody with Fab regions inhibiting both vascular endothelial growth factor-A and angiopoietin-2. Therefore, this study aimed to obtain short-term outcomes of intravitreal injection of faricimab (IVF) for the treatment of diabetic macular edema (DME) in daily clinical practice. Materials and Methods: A retrospective review was carried out on consecutive patients with DME who had been treated with IVF and were followed up for at least 1 month. Outcome measures included changes in logMAR best-corrected visual acuity (logMAR BCVA), central retinal thickness (CRT), number of IVF administrations, and safety. Clinical outcomes were also compared between the treatment-naïve and switch groups. Results: A total of 21 consecutive DME eyes from 19 patients were identified. The mean number of IVFs was 1.6 ± 0.8 during the mean follow-up time of 5.5 months. The overall mean logMAR BCVA following IVF was 0.236, 0.204, 0.190, and 0.224 at baseline, 1, 3, and 6 months, respectively, without a significant change from baseline to 1 month (p = 0.176) or for 6 months (p = 0.923). The overall mean CRT (μm) following IVF was 400.6, 346.6, 342.1, and 327.5 at baseline, 1, 3, and 6 months, respectively. CRT significantly decreased from baseline to 1 month (p = 0.001) but did not reach a significant level over 6 months following IVF (p = 0.070). No significant difference in BCVA or CRT was observed between the treatment-naïve and switch groups. No serious safety concerns were noted. Conclusions: IVF for the treatment of DME may preserve visual acuity and improve macular thickness without serious safety concerns in the short term in a real-world clinical setting.

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, predominantly affecting the lung parenchyma and peripheral airways, that results in progressive and irreversible airflow obstruction. COPD development is promoted by persistent pulmonary inflammation in response to several stimuli (e.g., cigarette smoke, bacterial and viral infections, air pollution, etc.). Angiogenesis, the formation of new blood vessels, and lymphangiogenesis, the formation of new lymphatic vessels, are features of airway inflammation in COPD. There is compelling evidence that effector cells of inflammation (lung-resident macrophages and mast cells and infiltrating neutrophils, eosinophils, basophils, lymphocytes, etc.) are major sources of a vast array of angiogenic (e.g., vascular endothelial growth factor-A (VEGF-A), angiopoietins) and/or lymphangiogenic factors (VEGF-C, -D). Further, structural cells, including bronchial and alveolar epithelial cells, endothelial cells, fibroblasts/myofibroblasts, and airway smooth muscle cells, can contribute to inflammation and angiogenesis in COPD. Although there is evidence that alterations of angiogenesis and, to a lesser extent, lymphangiogenesis, are associated with COPD, there are still many unanswered questions. [ABSTRACT FROM AUTHOR]

Introduction: Angiopoietin-2 (Ang-2) is a novel marker of coronary artery disease (CAD) and diabetes (DM). The aim was to evaluate Ang-2 as a potential new biomarker of non-ST elevation myocardial infarction (NSTEMI) in patients with or without type 2 DM (T2DM).Material and methods: This was a multi-center, prospective study that included 138 (males: 91/66%) consecutive patients hospitalized due to NSTEMI, T2DM, or different cardiac disorders. The subjects were divided into four study groups: group A: 28 patients with NSTEMI and T2DM; group B: 47 patients with NSTEMI without T2DM; group C: 31 patients with T2DM, without a history of CAD; group D: 32 patients as a control group. Patients with NSTEMI underwent urgent coronarography. Clinical characteristics including biomarkers (hs-CRP, hsTnT, NT-proBNP, VEGF, HbA1c), SYNTAX SCORE, type of intervention (PCI vs. CABG), and number of implanted stents were taken into account in the analysis.Results: Serum Ang-2 concentrations were significantly higher in patients with NSTEMI (group A: 1769 pg/ml; group B: 1757 pg/ml) and patients with T2DM (group C: 1993 pg/ml) as compared to the patients without CAD and without T2DM (group D: 866.8 pg/ml; p < 0.05). The prognostic accuracy of Ang-2 in NSTEMI diagnosis was determined with the area under the ROC curve (area under curve (AUC) = 0.63).Conclusions: Angiopoietin-2 serum concentration is elevated in the presence of NSTEMI in patients with and without T2DM and does not correspond to the degree of myocardial injury and hemodynamic status. Ang-2 remains elevated also in patients with T2DM without a history of CAD. [ABSTRACT FROM AUTHOR]

Purpose: Angiogenic markers in neuroendocrine neoplasms (NENs) have recently received increasing attention, but their clinical role remains unclear. The aim of this study was to evaluate the role of angiogenic markers in NEN aggressiveness and prognosis. Methods: We performed a prospective observational study including 46 consecutive patients with proven NENs of pulmonary (45.65%) and gastro-entero-pancreatic (GEP) (54.35%) origin and 29 healthy controls. Circulating pro-angiogenic factors were measured by ELISA assay. ANG2 tissue expression was evaluated in a subgroup of ten patients by immunohistochemistry. Results: The study demonstrated a significantly higher level of ANG2, ANG1, sTIE2, and PROK2 in patients affected by NENs compared to controls. In the NENs' group we measured that: (i) ANG2 levels were higher in poorly vs well-differentiated NENs: 4.85 (2.75–7.42) vs 3.16 (1.66–6.36) ng/ml, p = 0.046 and in tumor stage 3–4 compared to stage 1–2: 4.24 (2.66–8.72) vs 2.73 (1.53–5.70), p = 0.044; (ii) ANG2 and PROK2 were significantly higher in patents with progressive disease compared to stable disease: ANG2 = 6.26 (3.98–10.99) vs 2.73 (1.65–4.36) pg/ml, p = 0.001; PROK2 = 29.19 (28.42–32.25) vs 28.37 (28.14–28.91) pg/ml, p = 0.035. Immunohistochemistry confirmed ANG2 expression in tumor specimens. Conclusions: We documented higher levels of angiogenic markers in NENs, with an association between ANG2 serum levels and NENs morphology and staging. In both GEP and lung NENs, ANG2 and PROK2 are higher in case of tumor progression, suggesting a potential role as prognostic markers in NENs patients. [ABSTRACT FROM AUTHOR]

Cancer cells heavily utilise angiogenesis process to increase vascularisation for tumour mass growth and spread, so targeting this process is important to create an effective therapy. The AMHA1 strain of Newcastle disease virus (NDV) is an RNA virus with natural oncotropism. NDV induces direct tumour cytolysis, apoptosis, and immune stimulation. This work aimed to test NDV anti-angiogenic activity in a breast cancer model. To evaluate NDV's antitumour effect in vivo, NDV was tested against mammary adenocarcinoma AN3 transplanted in syngeneic immunocompetent mice. In vivo antiangiogenic activity was evaluated by quantifying the blood vessels in treated and control tumour sections. In vitro experiments that exposed AMN3 mammary adenocarcinoma cells and Hep-2 laryngeal carcinoma cells to NDV at different time intervals were performed to identify the exact mechanism of anti-angiogenesis by using angiogenesis microarray slides. In vivo results showed significant tumour regression and significant decrease in blood vessel formation in treated tumour sections. The in vitro microarray analysis of 14 different angiogenesis factors revealed that NDV downregulated angiopoietin-1, angiopoietin-2, and epidermal growth factor in mammary adenocarcinoma cells. However, NDV elicited a different effect on Hep-2 as represented by the downregulation of inducible protein 10, intracellular adhesion molecule-1, and basic fibroblast growth factor beta in NDVinfected tumour cells. It was found out that microarray analysis results helped interpret the in vivo data. The results suggested that the NDV oncolytic strain reduced angiogenesis by interfering with angiogenesis factors that might reduce tumour cell proliferation, infiltration, and invasion. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to determine if elevated concentration of soluble receptor tunica interna endothelial cell kinase-2 (Tie-2) in the amniotic fluid represent a risk factor for the subsequent development of preeclampsia (PE).Study Design: Amniotic fluid samples were collected as a part of routine clinical diagnostics from women referred to clinical care due to genetic indications. A total of 12 women with preeclampsia and 26 normotensive pregnant women were included in the study. Mean gestational age at amniocentesis was 17.92 weeks of pregnancy in preeclampsia and 17.88 in control group, respectively. Concentrations of sTie-2 in the amniotic fluid were determined by a standardized enzyme immunoassay.Results: Median concentration of Tie-2 in the amniotic fluid of PE patients was lower (median 1.109 ng/ml) compared with normotensive pregnant women (median 1.433 ng/Ml) but the difference was not statistically significant (p = 0.2973). Concentration of sTie-2 in the amniotic fluid did not significantly correlate with maternal age, gestational age at amniocentesis or delivery, as well as weight or length at birth. A difference in the gestational age at delivery in PE patients (mean 37.7 weeks) and normotensive pregnant controls (mean 39.8 weeks) was statistically significant (p = 0.0003). Birth weight and length of children delivered by PE women (mean 2863.3 g and 48.3 cm) were significantly lower compared with normal pregnancies (mean 3591.2 g and 51.4 cm, p = 0.0002 and p = 0.006, respectively).Conclusion: Our results suggest that amniotic fluid concentrations of sTie-2 do not predict development of PE and that further studies on biomarkers as predictors of PE should include other angiogenic biological response modifiers. [ABSTRACT FROM AUTHOR]