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Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) is associated with an increased cardiovascular risk, particularly the myeloperoxidase AAV serotype (MPO-AAV). Distinct alterations in monocyte phenotypes may cause accelerated atherosclerotic disease in AAV. A cohort including 43 AAV patients and 19 healthy controls was included for downstream analyses. Extensive phenotyping of monocytes and monocyte-derived macrophages was performed using bulk RNA-sequencing and flow cytometry. An in vitro transendothelial migration assay reflecting intrinsic adhesive and migratory capacities of monocytes was employed. Subsequent sub-analyses were performed to investigate differences between serological subtypes. Monocyte subset analysis showed increased classical monocytes during active disease, whereas non-classical monocytes were decreased compared to healthy controls (HC). RNA-sequencing revealed upregulation of distinct inflammatory pathways and lipid metabolism-related markers in monocytes of active AAV patients. No differences were detected in the intrinsic monocyte adhesion and migration capacity. Compared to proteinase-3(PR3)-AAV, monocytes of MPO-AAV patients in remission expressed genes related to inflammation, coagulation, platelet-binding and interferon signalling, whereas the expression of chemokine receptors indicative of acute inflammation and monocyte extravasation (i.e., CCR2 and CCR5) was increased in monocytes of PR3-AAV patients. During active disease, PR3-AAV was linked with elevated serum CRP and increased platelet counts compared to MPO-AAV. These findings highlight changes in monocyte subset composition and activation, but not in the intrinsic migration capacity of AAV monocytes. MPO-AAV monocytes are associated with sustained upregulation of inflammatory genes, whereas PR3-AAV monocytes exhibit chemokine receptor upregulation. These molecular changes may play a role in elevating cardiovascular risk as well as in the underlying pathophysiology of AAV. [Display omitted] • Monocytes are activated during active ANCA-associated vasculitis (AAV) and upregulate lipid metabolism-related markers. • AAV monocytes have a normal intrinsic adhesion and migration capacity although net migration likely rises by other mechanisms. • The two serological subsets MPO-AAV and PR3-AAV exhibit differences in monocyte activation and chemokine receptor expression. [ABSTRACT FROM AUTHOR]

Optimal management of risk factors is needed to improve long-term outcomes in AAV patients.▪ • Cardiovascular events (CV) are prevalent in patients with ANCA-associated vasculitis (AAV). • CV risk factors include age, HbA1c level, Diabetes Mellitus, and previous CV event. • Insulin resistance is frequent and might reflect previous steroid treatment. ANCA-associated vasculitis (AAV) has been associated with increased risk of cardiovascular (CV) events. The aim was to assess traditional and disease-related CV risk determinants in a two-centre prospective cohort of AAV patients. Patients were recruited from centres in the Netherlands and Canada. A comprehensive CV risk assessment was performed at inclusion. Subjects were followed up yearly for 3–5 years until the first CV event, death or end of follow-up. Cox proportional hazards analyses were performed to relate baseline characteristics to the first CV event. A total of 144 patients were included (mean age 62 years, female sex 44%, median Framingham risk score 14.3%). Insulin resistance was present in 73% of patients tested at inclusion, independent of concurrent prednisone therapy. After a median follow-up of 2.90 years, 16 patients (11%) experienced a CV event (14 non-fatal and 2 fatal). The incidence of CV events was 5.45 per 100 patient-years. Age, Framingham risk score, HbA1c level, Diabetes Mellitus (DM), and previous CV event were significantly associated with CV events. Other factors, such as sex, impaired renal function, dyslipidemia, hypertension, smoking history and microalbuminuria, or disease-specific variables, like ANCA serotype or disease activity, were not significantly related to CV events in univariable or age-adjusted cox regression analysis. Determinants of an increased CV risk were identified. Disease-related factors and treatments can further modify individual risk factors, such as for steroids causing chronic insulin resistance and DM. Treatment of risk factors is essential to optimize long-term outcomes in AAV patients. [ABSTRACT FROM AUTHOR]

Rationale: Ecstasy is a commonly used psychoactive drug with 3,4-methylenedioxymethamphetamine (MDMA) as the main content. Importantly, it has been suggested that use of MDMA may be neurotoxic particularly for serotonergic (5-hydroxytryptamine (5-HT)) neurons. In the past decades, several molecular imaging studies examined directly in vivo the effects of ecstasy/MDMA on neurotransmitter systems. Objectives: The objective of the present study is to review the effects of ecstasy/MDMA on neurotransmitter systems as assessed by molecular imaging studies in small animals, non-human primates and humans. Methods: A search in PubMed was performed. Eighty-eight articles were found on which inclusion and exclusion criteria were applied. Results: Thirty-three studies met the inclusion criteria; all were focused on the 5-HT or dopamine (DA) system. Importantly, 9 out of 11 of the animal studies that examined the effects of MDMA on 5-HT transporter (SERT) availability showed a significant loss of binding potential. In human studies, this was the case for 14 out of 16 studies, particularly in heavy users. In abstinent users, significant recovery of SERT binding was found over time. Most imaging studies in humans that focused on the DA system did not find any significant effect of ecstasy/MDMA use. Conclusions: Preclinical and clinical molecular imaging studies on the effects of ecstasy/MDMA use/administration on neurotransmitter systems show quite consistent alterations of the 5-HT system. Particularly, in human studies, loss of SERT binding was observed in heavy ecstasy users, which might reflect 5-HT neurotoxicity, although alternative explanations (e.g. down-regulation of the SERT) cannot be excluded. [ABSTRACT FROM AUTHOR]

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE) that occurs in about half of patients. LN is characterized by glomerular deposition of immune complexes, leading to subendothelial, mesangial and subepithelial electron dense deposits, triggering immune cell infiltration and glomerular as well as tubulointerstitial injury. Monocytes and macrophages are abundantly present in inflammatory lesions, both in glomeruli and the tubulointerstitium. Here we discuss how monocytes and macrophages are involved in this process and how monocytes and macrophages may represent specific therapeutic targets to control LN. • Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE) • There is an unmet need for specific immunosuppressive therapy in LN treatment • Monocytes and macrophages are abundantly present in LN inflammatory lesions • Renal macrophages are heterogeneous and have both pro- and anti-inflammatory functions leading to chronic inflammation, fibrosis and loss of kidney function • Targeted macrophage treatment is an important potential new therapeutic avenue in LN [ABSTRACT FROM AUTHOR]

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare heterogeneous disease in which treatment must be initiated early to prevent irreversible organ damage and death. There are several diseases that can mimic AAV, even in the presence of positive ANCA serology and/or histological evidence of vasculitis, as demonstrated in this case series. We reflect on the diagnostic approach of patients with AAV and provide an overview of AAV-mimicking diseases that can be considered in patients with atypical disease presentation or course. [ABSTRACT FROM AUTHOR]

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) are characterized by inflammation of small-to-medium-sized blood vessels and the presence of autoantibodies against cytoplasmic proteases sited in neutrophils and monocytes. Increasing evidence indicates a substantial role of monocytes and macrophages in the pathogenesis of AAV. Activated monocytes and macrophages contribute to necroinflammation in peripheral vasculitic lesions as well as to central and peripheral mechanisms of autoimmunity. The intermediate monocyte subset (CD14++CD16+) is increased and monocytes show elevated expression of CD14, Toll-like receptor 2/4, MHCII and integrins, likely reflecting activation and increased monocyte extravasation. Monocytes differentiate locally predominantly into alternatively activated (M2) macrophages, which are known for cell-clearance and phagocytosis, but may ultimately lead to fibrosis. Phagocytotic function of macrophages can be impaired by surface expression of cytoplasmic proteases on apoptotic neutrophils and causes release of inflammatory cytokines and immunogenic contents, presumably resulting in a vicious circle of increased neutrophil, T and B cell activation and consequent ANCA production. Considering their crucial role in initiating necroinflammation as well as fibrogenesis, monocytes and macrophages may represent a logic first-line target for new treatment options in AAV. [Display omitted] • Monocytes and macrophages contribute to necroinflammation and autoimmunity in AAV. • Monocytes express markers of activation and the CD14++ CD16+ subset is increased. • Monocytes differentiate into alternatively activated macrophages (M2), promoting fibrosis. • Targeting activated monocytes and macrophages may form new therapeutic options. [ABSTRACT FROM AUTHOR]

Irisin, a skeletal-muscle secreted myokine, facilitates muscle-bone crosstalk and skeletal remodeling in part by its action on osteoblasts and osteocytes. In this study, we investigated whether irisin directly regulates osteoclasts. In vitro, irisin (2-10 ng/mL) increased osteoclast differentiation in C57BL/6J mouse bone marrow progenitors; however, this increase was blocked by a neutralizing antibody to integrin aVb5. Irisin also increased bone resorption on several substrates in situ. RNAseq revealed differential gene expression induced by irisin including upregulation of markers for osteoclast differentiation and resorption, as well as osteoblast-stimulating 'clastokines'. Forced expression of the irisin precursor Fndc5 in transgenic C57BL/6J mice resulted in lower bone mass at three ages and greater in vitro osteoclastogenesis from Fndc5-transgenic bone marrow progenitors. This study demonstrates that irisin acts directly on osteoclast progenitors to increase differentiation and promote bone resorption, supporting the tenet that irisin not only stimulates bone remodeling but may also be an important counter-regulatory hormone. [ABSTRACT FROM AUTHOR]

Bone formation and resorption are typically coupled, such that the efficacy of anabolic osteoporosis treatments may be limited by bone destruction. The multi-kinase inhibitor YKL-05-099 potently inhibits salt inducible kinases (SIKs) and may represent a promising new class of bone anabolic agents. Here, we report that YKL-05-099 increases bone formation in hypogonadal female mice without increasing bone resorption. Postnatal mice with inducible, global deletion of SIK2 and SIK3 show increased bone mass, increased bone formation, and, distinct from the effects of YKL- 05--099, increased bone resorption. No cell-intrinsic role of SIKs in osteoclasts was noted. In addition to blocking SIKs, YKL-05-099 also binds and inhibits CSF1R, the receptor for the osteoclastogenic cytokine M-CSF. Modeling reveals that YKL-05--099 binds to SIK2 and CSF1R in a similar manner. Dual targeting of SIK2/3 and CSF1R induces bone formation without concomitantly increasing bone resorption and thereby may overcome limitations of most current anabolic osteoporosis therapies. [ABSTRACT FROM AUTHOR]

Background: Studies have suggested incremental short-term adverse events (AE) after repeated vaccination. In this report, we assessed occurrence and risk factors for short-term AEs following repeated SARS-CoV-2 vaccination in patients with various immune-mediated inflammatory diseases (IMIDs).Methods: Self-reported daily questionnaires on AEs during the first 7 days after vaccination were obtained of 2259 individuals (2081 patients and 178 controls) participating in an ongoing prospective multicenter cohort study on SARS-CoV-2 vaccination in patients with various IMIDs in the Netherlands (T2B-COVID). Relative risks were calculated for potential risk factors associated with clinically relevant AE (rAE), defined as AE lasting longer than 2 days or impacting daily life.Results: In total, 5454 vaccinations were recorded (1737 first, 1992 second and 1478 third vaccinations). Multiple sclerosis, Crohn's disease and rheumatoid arthritis were the largest disease groups. rAEs were reported by 57.3% (95% CI 54.8-59.8) of patients after the first vaccination, 61.5% (95% CI 59.2-63.7) after the second vaccination and 58% (95% CI 55.3-60.6) after the third vaccination. At day 7 after the first, second and third vaccination, respectively, 7.6% (95% CI 6.3-9.1), 7.4% (95% CI 6.2-8.7) and 6.8% (95% CI 5.4-8.3) of patients still reported AEs impacting daily life. Hospital admissions and allergic reactions were uncommon (<0.7%). Female sex (aRR 1.43, 95% CI 1.32-1.56), age below 50 (aRR 1.14, 95% CI 1.06-1.23), a preceding SARS-CoV-2 infection (aRR 1.14, 95% CI 1.01-1.29) and having an IMID (aRR 1.16, 95% CI 1.01-1.34) were associated with increased risk of rAEs following a vaccination. Compared to the second vaccination, the first vaccination was associated with a lower risk of rAEs (aRR 0.92, 95% CI 0.84-0.99) while a third vaccination was not associated with increased risk on rAEs (aRR 0.93, 95% CI 0.84-1.02). BNT162b2 vaccines were associated with lower risk on rAEs compared to CX-024414 (aRR 0.86, 95% CI 0.80-0.93).Conclusions: A third SARS-CoV-2 vaccination was not associated with increased risk of rAEs in IMID patients compared to the second vaccination. Patients with an IMID have a modestly increased risk of rAEs after vaccination when compared to controls. Most AEs are resolved within 7 days; hospital admissions and allergic reactions were uncommon.Trial Registration: NL74974.018.20 , Trial ID: NL8900. Registered on 9 September 2020. [ABSTRACT FROM AUTHOR]

Conditional deletion of the PTH receptor (Pth1r) in mesenchymal progenitors reduces osteoblast differentiation and bone mass while enhancing adipogenesis and bone marrow adipose tissue. Mechanistically, PTH suppresses the expression of Zfp467 , a pro-adipogenic zinc finger transcription factor. Consequently, Pth1r deficiency in mesenchymal progenitors leads to increased Zfp467 expression. Based on these observations, we hypothesized that genetic loss of Zfp467 would lead to a shift in marrow progenitor cell fate towards osteogenesis and increased bone mass. To test this hypothesis, we generated Zfp467−/− mice. Zfp467−/− mice (−/−) were significantly smaller than Zfp467+/+ mice (+/+). μ CT showed significantly higher trabecular bone and cortical bone area in −/− vs. +/+ , and histomorphometry showed higher structural and dynamic formation parameters in −/− mice vs. +/+. Femoral gene expression including Alpl, Sp7 , and Acp5 were increased in −/− mice, whereas Adiponectin, Cebpa, Lepr , and Ppraγ mRNA were lower in −/− mice. Similarly, Fabp4 and Lep in the inguinal depot were also decreased in −/− mice. Moreover, marrow adipocyte numbers were reduced in −/− vs +/+ mice (p <0.007). In vitro , COBs and BMSCs −/− showed more positive ALP and Alizarin Red staining and a decrease in ORO droplets. Pth1r mRNA and protein levels were increased in COBs and BMSCs from −/− mice vs +/+ (p <0.02 for each parameter, −/− vs. +/+). −/− cells also exhibited enhanced endogenous levels of cAMP vs. control cells. Moreover, in an ovariectomy (OVX) mouse model, Zfp467−/− mice had significantly lower fat mass but similar bone mass compared to OVX +/+ mice. In contrast, in a high fat diet (HFD) mouse model, in addition to reduced adipocyte volume and adipogenesis related gene expression in both peripheral and bone marrow fat tissue, greater osteoblast number and higher osteogenesis related gene expression were also observed in −/− HFD mice vs. +/+ HFD mice. Taken together, these results demonstrate that ZFP467 negatively influences skeletal homeostasis and favors adipogenesis. Global deletion of Zfp467 increases PTHR1, cAMP and bone turnover, hence its repression is a component of PTH signaling and its regulation. These data support a critical role for Zfp467 in early lineage allocation and provide a novel potential mechanism by which PTH acts in an anabolic manner on the bone remodeling unit. Unlabelled Image • Zfp467 −/− mice have increased bone mass and reduced adipose tissue. • Zfp467 −/− mice have higher level of Pth1r in bone and related cells. • Zfp467 −/− mice are resistant to OVX induced adiposity. • Zfp467 −/− mice are resistant to high fat diet-induced adiposity and weight gain. [ABSTRACT FROM AUTHOR]