Th1 cells reduce the osteoblast-like phenotype in valvular interstitial cells by inhibiting NLRP3 inflammasome activation in macrophages.

BACKGROUND AND AIMS: Inflammation is initiates the propagation phase of aortic valve calcification. The activation of NLRP3 signaling in macrophages plays a crucial role in the progression of calcific aortic valve stenosis (CAVS). IFN-γ regulates NLRP3 activity in macrophages. This study aimed to explore the mechanism of IFN-γ regulation and its impact on CAVS progression and valve interstitial cell transdifferentiation. METHODS AND RESULTS: The number of Th1 cells and the expression of IFN-γ and STAT1 in the aortic valve, spleen and peripheral blood increased significantly as CAVS progressed. To explore the mechanisms underlying the roles of Th1 cells and IFN-γ, we treated CAVS mice with IFN-γ-AAV9 or an anti-IFN-γ neutralizing antibody. While IFN-γ promoted aortic valve calcification and dysfunction, it significantly decreased NLRP3 signaling in splenic macrophages and Ly6C+ monocytes. In vitro coculture showed that Th1 cells inhibited NLPR3 activation in ox-LDL-treated macrophages through the IFN-γR1/IFN-γR2-STAT1 pathway. Compared with untreated medium, conditioned medium from Th1-treated bone marrow-derived macrophages reduced the osteogenic calcification of valvular interstitial cells. CONCLUSION: Inhibition of the NLRP3 inflammasome by Th1 cells protects against valvular interstitial cell calcification as a negative feedback mechanism of adaptive immunity toward innate immunity. This study provides a precision medicine strategy for CAVS based on the targeting of anti-inflammatory mechanisms.

Treatment of calcinosis cutis associated with autoimmune connective tissue diseases.

Calcinosis cutis is a condition that is commonly associated with autoimmune connective tissue diseases. It is characterized by the deposition of insoluble calcium salts in the skin and subcutaneous tissue, which can cause pain, impair function, and have significant impacts on quality of life. Calcinosis cutis is difficult to manage because there is no generally accepted treatment: evidence supporting treatments is mostly comprised of case reports and case series, sometimes yielding mixed findings. Both pharmacologic and procedural interventions have been proposed to improve calcinosis cutis, and each may be suited to different clinical scenarios. This review summarizes current treatment options for calcinosis cutis, with discussion of recommendations based on patient-specific factors and disease severity.

The α-Gal KO Mouse Animal Model is a Reliable and Predictive Tool for the Immune-Mediated Calcification Assessment of Heart Valve Bioprostheses.

BACKGROUND: Recent studies highlighted the presence of anti-α-Gal antibodies in patients implanted with commercial bioprosthetic heart valves (BHVs). BHVs expose residual α-Gal xenoantigen and their recognition by the circulating anti-Gal antibodies leads to opsonization of the device's tissue component with the consequent triggering of a deterioration pathway that culminates with calcification. Small animal models such as mice and rats have been broadly involved in the in vivo testing of biomaterials by subcutaneous implantation, especially for the effectiveness of BHVs anti-calcific treatments. However, since models employed for this purpose express α-Gal antigen, the implantation of BHVs' leaflets does not elicit a proper immunological response, so the calcification propensity may be dramatically underestimated. METHODS: An α-Gal knockout (KO) mouse model has been created, using the CRISP/Cas9 approach, and adopted to assess the calcification potential of commercial BHVs leaflets through the surgical implantation in the back subcutis area. Calcium quantification was performed by inductively coupled plasma analysis; immune response against the BHVs leaflets and α-Gal silencing was evaluated through immunological assays. RESULTS: Two months after the implantation of commercial BHV leaflets, the anti-Gal antibody titers in KO mice doubled when compared with those found in wild-type (WT) ones. Leaflets explanted from KO mice, after one month, showed a four-time increased calcium deposition concerning the ones explanted from WT. The degree of silencing of α-Gal varied, depending on the specific organ that was assessed. In any case, the animal model was suitable for evaluating implanted tissue responses. CONCLUSIONS: Such mouse model proved to be an accurate tool for the study of the calcific propensity of commercial BHVs leaflets than those hitherto used. Given its reliability, it could also be successfully used to study even other diseases in which the possible involvement of α-Gal has been observed.

Subclinical maternal autoimmune disease leading to congenital high degree atrioventricular block: Case report and review of the literature.

Maternal autoimmune disease is the most common cause of congenital heart block (CHB), a rare illness characterized by fibrosis and calcification of the fetal atrioventricular (AV) node due to maternal autoantibodies anti-SSA/Ro and anti-SSB/La. We report the full autopsy and clinical information on a female neonate with high degree AV block and calcification in the AV node, atrial approaches to the AV node, and both right and left bundle branches, born to a 27-year-old female with subclinical autoimmune disease.

Interferons Are Pro-Inflammatory Cytokines in Sheared-Stressed Human Aortic Valve Endothelial Cells.

Calcific aortic valve disease (CAVD) is an athero-inflammatory process. Growing evidence supports the inflammation-driven calcification model, mediated by cytokines such as interferons (IFNs) and tumor necrosis factor (TNF)-α. Our goal was investigating IFNs' effects in human aortic valve endothelial cells (VEC) and the potential differences between aortic (aVEC) and ventricular (vVEC) side cells. The endothelial phenotype was analyzed by Western blot, qPCR, ELISA, monocyte adhesion, and migration assays. In mixed VEC populations, IFNs promoted the activation of signal transducers and activators of transcription-1 and nuclear factor-κB, and the subsequent up-regulation of pro-inflammatory molecules. Side-specific VEC were activated with IFN-γ and TNF-α in an orbital shaker flow system. TNF-α, but not IFN-γ, induced hypoxia-inducible factor (HIF)-1α stabilization or endothelial nitric oxide synthase downregulation. Additionally, IFN-γ inhibited TNF-α-induced migration of aVEC. Also, IFN-γ triggered cytokine secretion and adhesion molecule expression in aVEC and vVEC. Finally, aVEC were more prone to cytokine-mediated monocyte adhesion under multiaxial flow conditions as compared with uniaxial flow. In conclusion, IFNs promote inflammation and reduce TNF-α-mediated migration in human VEC. Moreover, monocyte adhesion was higher in inflamed aVEC sheared under multiaxial flow, which may be relevant to understanding the initial stages of CAVD.

Innate and adaptive immunity: the understudied driving force of heart valve disease.

Calcific aortic valve disease (CAVD), and its clinical manifestation that is calcific aortic valve stenosis, is the leading cause for valve disease within the developed world, with no current pharmacological treatment available to delay or halt its progression. Characterized by progressive fibrotic remodelling and subsequent pathogenic mineralization of the valve leaflets, valve disease affects 2.5% of the western population, thus highlighting the need for urgent intervention. Whilst the pathobiology of valve disease is complex, involving genetic factors, lipid infiltration, and oxidative damage, the immune system is now being accepted to play a crucial role in pathogenesis and disease continuation. No longer considered a passive degenerative disease, CAVD is understood to be an active inflammatory process, involving a multitude of pro-inflammatory mechanisms, with both the adaptive and the innate immune system underpinning these complex mechanisms. Within the valve, 15% of cells evolve from haemopoietic origin, and this number greatly expands following inflammation, as macrophages, T lymphocytes, B lymphocytes, and innate immune cells infiltrate the valve, promoting further inflammation. Whether chronic immune infiltration or pathogenic clonal expansion of immune cells within the valve or a combination of the two is responsible for disease progression, it is clear that greater understanding of the immune systems role in valve disease is required to inform future treatment strategies for control of CAVD development.

Muscle Tissue Damage and Recovery After EV71 Infection Correspond to Dynamic Macrophage Phenotypes.

Enterovirus 71 (EV71) is a positive single-stranded RNA virus from the enterovirus genus of the Picornaviridae family. Most young children infected with EV71 develop mild symptoms of hand, foot and mouth disease, but some develop severe symptoms with neurological involvement. Limb paralysis from EV71 infection is presumed to arise mainly from dysfunction of motor neurons in the spinal cord. However, EV71 also targets and damages skeletal muscle, which may also contribute to the debilitating symptoms. In this study, we have delineated the impacts of EV71 infection on skeletal muscle using a mouse model. Mouse pups infected with EV71 developed limb paralysis, starting at day 3 post-infection and peaking at day 5-7 post-infection. At later times, mice recovered gradually but not completely. Notably, severe disease was associated with high levels of myositis accompanied by muscle calcification and persistent motor end plate abnormalities. Interestingly, macrophages exhibited a dynamic change in phenotype, with inflammatory macrophages (CD45+CD11b+Ly6Chi) appearing in the early stage of infection and anti-inflammatory/restorative macrophages (CD45+CD11b+Ly6Clow/-) appearing in the late stage. The presence of inflammatory macrophages was associated with severe inflammation, while the restorative macrophages were associated with recovery. Altogether, we have demonstrated that EV71 infection causes myositis, muscle calcification and structural defects in motor end plates. Subsequent muscle regeneration is associated with a dynamic change in macrophage phenotype.

Inflammatory and Biomechanical Drivers of Endothelial-Interstitial Interactions in Calcific Aortic Valve Disease.

Calcific aortic valve disease is dramatically increasing in global burden, yet no therapy exists outside of prosthetic replacement. The increasing proportion of younger and more active patients mandates alternative therapies. Studies suggest a window of opportunity for biologically based diagnostics and therapeutics to alleviate or delay calcific aortic valve disease progression. Advancement, however, has been hampered by limited understanding of the complex mechanisms driving calcific aortic valve disease initiation and progression towards clinically relevant interventions.

Collision Lesions of Calcifying Pseudoneoplasm of the Neuraxis and Rheumatoid Nodules: A Case Report With New Pathogenic Insights.

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumor-like lesion with unclear pathogenesis. Collision lesions of CAPNONs with neoplasms are occasionally reported. In this article, we report the first case of collision lesions between CAPNON and rheumatoid nodules (RNs) in a patient with systemic lupus erythematosus. The patient was a 51-year-old female who presented with lower back pain and subsequently a lower back mass over 2 years. Spinal magnetic resonance imaging demonstrated a heterogeneous, partially calcified mass centered in the L3-4 paravertebral regions. A biopsy of the mass was diagnostic of CAPNON. As the mass grew over the following 5 months, it was resected en bloc. Its pathological examination revealed collision lesions of RNs at different histopathological stages and CAPNON lesions, and transitional lesions exhibiting combined RN and CAPNON features, with immune cell infiltrates. Our findings provide new evidence for an immune-mediated reactive process and insights into the pathogenies of CAPNON.

Aberrant RhoA activation in macrophages increases senescence-associated secretory phenotypes and ectopic calcification in muscular dystrophic mice.

Duchenne Muscular Dystrophy (DMD) patients often suffer from both muscle wasting and osteoporosis. Our previous studies have revealed reduced regeneration potential in skeletal muscle and bone, concomitant with ectopic calcification of soft tissues in double knockout (dKO, dystrophin-/-; utrophin-/-) mice, a severe murine model for DMD. We found significant involvement of RhoA/ROCK (Rho-Associated Protein Kinase) signaling in mediating ectopic calcification of muscles in dKO mice. However, the cellular identity of these RhoA+ cells, and the role that RhoA plays in the chronic inflammation-associated pathologies has not been elucidated. Here, we report that CD68+ macrophages are highly prevalent at the sites of ectopic calcification of dKO mice, and that these macrophages highly express RhoA. Macrophages from dKO mice feature a shift towards a more pro-inflammatory M1 polarization and an increased expression of various senescence-associated secretory phenotype (SASP) factors that was reduced with the RhoA/ROCK inhibitor Y-27632. Further, systemic inhibition of RhoA activity in dKO mice led to reduced number of RhoA+/CD68+ cells, as well as a reduction in fibrosis and ectopic calcification. Together, these data revealed that RhoA signaling may be a key regulator of imbalanced mineralization in the dystrophic musculoskeletal system and consequently a therapeutic target for the treatment of DMD or other related muscle dystrophies.

Breast Cancer and Microcalcifications: An Osteoimmunological Disorder?

The presence of microcalcifications in the breast microenvironment, combined with the growing evidences of the possible presence of osteoblast-like or osteoclast-like cells in the breast, suggest the existence of active processes of calcification in the breast tissue during a woman's life. Furthermore, much evidence that osteoimmunological disorders, such as osteoarthritis, rheumatoid arthritis, or periodontitis influence the risk of developing breast cancer in women exists and vice versa. Antiresorptive drugs benefits on breast cancer incidence and progression have been reported in the past decades. More recently, biological agents targeting pro-inflammatory cytokines used against rheumatoid arthritis also demonstrated benefits against breast cancer cell lines proliferation, viability, and migratory abilities, both in vitro and in vivo in xenografted mice. Hence, it is tempting to hypothesize that breast carcinogenesis should be considered as a potential osteoimmunological disorder. In this review, we compare microenvironments and molecular characteristics in the most frequent osteoimmunological disorders with major events occurring in a woman's breast during her lifetime. We also highlight what the use of bone anabolic drugs, antiresorptive, and biological agents targeting pro-inflammatory cytokines against breast cancer can teach us.

Unique Characteristics of Epilepsy Development in Neurocysticercosis.

The parasitic helminth infection neurocysticercosis (NCC) is the most common cause of adult-acquired epilepsy in the world. Despite the serious consequences of epilepsy due to this infection, an in-depth review of the distinct characteristics of epilepsy due to neurocysticercosis has never been conducted. In this review, we evaluate the relationship between NCC and epilepsy and the unique characteristics of epilepsy caused by NCC. We also discuss recent advances in our understanding of NCC-related epilepsy, including the importance of anti-inflammatory therapies, the association between NCC and temporal lobe epilepsy, and the recent discovery of biomarkers of severe epilepsy development in individuals with NCC and seizures.

Macrophages Promote Aortic Valve Cell Calcification and Alter STAT3 Splicing.

OBJECTIVE: Macrophages have been described in calcific aortic valve disease, but it is unclear if they promote or counteract calcification. We aimed to determine how macrophages are involved in calcification using the Notch1+/- model of calcific aortic valve disease. Approach and Results: Macrophages in wild-type and Notch1+/- murine aortic valves were characterized by flow cytometry. Macrophages in Notch1+/- aortic valves had increased expression of MHCII (major histocompatibility complex II). We then used bone marrow transplants to test if differences in Notch1+/- macrophages drive disease. Notch1+/- mice had increased valve thickness, macrophage infiltration, and proinflammatory macrophage maturation regardless of transplanted bone marrow genotype. In vitro approaches confirm that Notch1+/- aortic valve cells promote macrophage invasion as quantified by migration index and proinflammatory phenotypes as quantified by Ly6C and CCR2 positivity independent of macrophage genotype. Finally, we found that macrophage interaction with aortic valve cells promotes osteogenic, but not dystrophic, calcification and decreases abundance of the STAT3ß isoform. CONCLUSIONS: This study reveals that Notch1+/- aortic valve disease involves increased macrophage recruitment and maturation driven by altered aortic valve cell secretion, and that increased macrophage recruitment promotes osteogenic calcification and alters STAT3 splicing. Further investigation of STAT3 and macrophage-driven inflammation as therapeutic targets in calcific aortic valve disease is warranted.

Calcifying fibrous tumour: An IgG4-related disease or not?

Calcifying fibrous tumour (CFT) has some of the histopathological features, such as abundant plasma cells and stromal fibrosis, that are exhibited by IgG4-related diseases (IgG4-RD). The possible role of IgG4-positive plasma cells in calcifying fibrous tumour was investigated. The aim of this study was to determine any potential relationship between IgG4-RD and CFT. Thirteen cases with a total of 16 CFTs were reviewed. Lesion samples were immunostained with anti-IgG4 and anti-IgG antibodies. The number of IgG4-positive and IgG-positive plasma cells (IgG + PC) and their ratios were estimated. Plasma cells were found in all tumours. IgG4-positive plasma cells ranged from 0 to 71 per high-power field (HPF; mean 17.8/HPF), and IgG + PC ranged from 2 to 93/HPF (mean 42.6/HPF). The IgG4/IgG ratio ranged from 0% to 80% (mean 29%). There were seven tumours with the ratio of IgG4/IgG + PC that exceeded 40%. Various degrees of stromal fibrosis were present in eight tumours. All tumours have variable calcification. The histopathological features of CFT were found to be similar to those of IgG4-RD. Some CFT also showed a high number of IgG4-positive plasma cells, and the ratio of IgG4/IgG + PC exceeded 40%, most notably in patients with concomitant inflammatory or autoimmune disease. The long-term follow-up showed no evidence of IgG4-RD in any of these patients. Our findings suggest that while CFT overlaps morphologically with IgG4-RD, it probably should not be classified as an IgG4-RD.

Diacylglycerol Kinase ζ Regulates Macrophage Responses in Juvenile Arthritis and Cytokine Storm Syndrome Mouse Models.

Dysregulation of monocyte and macrophage responses are often observed in children with systemic juvenile idiopathic arthritis (sJIA) and cytokine storm syndrome (CSS), a potentially fatal complication of chronic rheumatic diseases. Both conditions are associated with activation of TLR signaling in monocyte and macrophage lineage cells, leading to overwhelming inflammatory responses. Despite the importance of TLR engagement in activating proinflammatory macrophages, relatively little is known about activation of intrinsic negative regulatory pathways to attenuate excessive inflammatory responses. In this study, we demonstrate that loss of diacylglycerol (DAG) kinase (Dgk) ζ, an enzyme which converts DAG into phosphatidic acid, limits inflammatory cytokine production in an arthritic mouse model dependent on TLR2 signaling and in a CSS mouse model dependent on TLR9 signaling. In vitro, Dgkζ deficiency results in reduced production of TNF-α, IL-6, and IL-1ß and in limited M1 macrophage polarization. Mechanistically, Dgkζ deficiency decreases STAT1 and STAT3 phosphorylation. Moreover, Dgkζ levels are increased in macrophages derived from mice with CSS or exposed to plasma from sJIA patients with active disease. Our data suggest that Dgkζ induction in arthritic conditions perpetuates systemic inflammatory responses mediated by macrophages and highlight a potential role of Dgkζ-DAG/phosphatidic acid axis as a modulator of inflammatory cytokine production in sJIA and CSS.

Total Absence of Dystrophin Expression Exacerbates Ectopic Myofiber Calcification and Fibrosis and Alters Macrophage Infiltration Patterns.

Duchenne muscular dystrophy (DMD) causes severe disability and death of young men because of progressive muscle degeneration aggravated by sterile inflammation. DMD is also associated with cognitive and bone-function impairments. This complex phenotype results from the cumulative loss of a spectrum of dystrophin isoforms expressed from the largest human gene. Although there is evidence for the loss of shorter isoforms having impact in the central nervous system, their role in muscle is unclear. We found that at 8 weeks, the active phase of pathology in dystrophic mice, dystrophin-null mice (mdxßgeo) presented with a mildly exacerbated phenotype but without an earlier onset, increased serum creatine kinase levels, or decreased muscle strength. However, at 12 months, mdxßgeo diaphragm strength was lower, whereas fibrosis increased, compared with mdx. The most striking features of the dystrophin-null phenotype were increased ectopic myofiber calcification and altered macrophage infiltration patterns, particularly the close association of macrophages with calcified fibers. Ectopic calcification had the same temporal pattern of presentation and resolution in mdxßgeo and mdx muscles, despite significant intensity differences across muscle groups. Comparison of the rare dystrophin-null patients against those with mutations affecting full-length dystrophins may provide mechanistic insights for developing more effective treatments for DMD.

Epilepsy, cerebral calcifications, and gluten-related disorders: Are anti-transglutaminase 6 antibodies the missing link?

PURPOSE: Gluten-related disorders (GRDs) are a group of immune-mediated diseases often associated to neurologic manifestations. Epilepsies with cerebral calcifications, with or without coeliac disease (CD), are rare neurological disorders characterized by childhood-onset focal seizures, often refractory to antiepileptic drugs. Transglutaminase 6 antibodies (anti-TG6) have been considered a biomarker for gluten-related ataxia and neuropathy, but their prevalence in epilepsies with cerebral calcifications is unknown. The aim of this study is to evaluate anti-TG6 prevalence in patients with epilepsies and cerebral calcifications. METHOD: this was a cross-sectional study conducted at five Italian epilepsy centres. The following groups were included. Group 1: nine patients with CD, posterior cerebral calcifications and epilepsy (CEC); group 2: nine patients with epilepsy and posterior cerebral calcifications, without CD; group 3: twenty patients with focal epilepsy of unknown etiology; group 4: twenty-two healthy controls (HC). All subjects were tested for serological evidence of anti-TG6 IgA and IgG. Differences among groups were analysed using χ ² test. RESULTS: anti-TG6 were present in 1/9 subjects (11%) of group 1, 2/9 subjects (22%) of group 2, 0/20 subjects in group 3, 3/22 (13.6%) of HC. No significant difference was found among the 4 groups. CONCLUSIONS: Anti-TG6 do not seem to be associated to epilepsies with cerebral calcifications.

New Insights into the Roles of Monocytes/Macrophages in Cardiovascular Calcification Associated with Chronic Kidney Disease.

Cardiovascular disease (CVD) is an important cause of death in patients with chronic kidney disease (CKD), and cardiovascular calcification (CVC) is one of the strongest predictors of CVD in this population. Cardiovascular calcification results from complex cellular interactions involving the endothelium, vascular/valvular cells (i.e., vascular smooth muscle cells, valvular interstitial cells and resident fibroblasts), and monocyte-derived macrophages. Indeed, the production of pro-inflammatory cytokines and oxidative stress by monocyte-derived macrophages is responsible for the osteogenic transformation and mineralization of vascular/valvular cells. However, monocytes/macrophages show the ability to modify their phenotype, and consequently their functions, when facing environmental modifications. This plasticity complicates efforts to understand the pathogenesis of CVC-particularly in a CKD setting, where both uraemic toxins and CKD treatment may affect monocyte/macrophage functions and thereby influence CVC. Here, we review (i) the mechanisms by which each monocyte/macrophage subset either promotes or prevents CVC, and (ii) how both uraemic toxins and CKD therapies might affect these monocyte/macrophage functions.