Regulation of cardiac fibroblasts by lymphocytes after a myocardial infarction: playing in the major league.

Cardiac fibrosis is a pathological condition characterized by excessive accumulation of extracellular matrix components within the myocardium, which can lead to impaired cardiac function and heart failure. Studies have shown that lymphocytes including B and T cells play important roles in the development and progression of cardiac fibrosis after a myocardial infarction. In this review, we focus on the regulation of cardiac fibrosis by lymphocyte subsets, with a particular emphasis on CD4+ and CD8+ T cells and their effects on fibroblasts and cardiac remodeling. We also highlight areas for further exploration of the interactions between T cells and fibroblasts necessary for understanding and treating cardiac fibrosis and heart failure.

SPARC production by bone marrow-derived cells contributes to myocardial fibrosis in pressure overload.

In human heart failure and in murine hearts with left-ventricular pressure overload (LVPO), increases in fibrosis are associated with increases in myocardial stiffness. Secreted protein acidic and rich in cysteine (SPARC) is shown to be necessary for both cardiac fibrosis and increases in myocardial stiffness in response to LVPO; however, cellular sources of cardiac SPARC are incompletely defined. Irradiation and bone marrow transfer were undertaken to test the hypothesis that SPARC expression by bone marrow-derived cells is an important mediator of fibrosis in LVPO. In recipient SPARC-null mice transplanted with donor wild-type (WT) bone marrow and subjected to LVPO, levels of fibrosis similar to that of WT mice were found despite the lack of SPARC expression by resident cells. In recipient WT mice with donor SPARC-null bone marrow, significantly less fibrosis versus that of WT mice was found despite the expression of SPARC by resident cells. Increases in myocardial stiffness followed a similar pattern to that of collagen deposition. Myocardial macrophages were significantly reduced in SPARC-null mice with LVPO versus that of WT mice. Recipient SPARC-null mice transplanted with donor WT bone marrow exhibited an increase in cardiac macrophages versus that of SPARC-null LVPO and donor WT mice with recipient SPARC-null bone marrow. Expression of vascular cellular adhesion molecule (VCAM), a previously identified binding partner of SPARC, was assessed in all groups and with the exception of WT mice, increases in VCAM immunoreactivity with LVPO were observed. However, no differences in VCAM expression between bone marrow transplant groups were noted. In conclusion, SPARC expression by bone marrow-derived cells was critical for fibrotic deposition of collagen and influenced the expansion of myocardial macrophages in response to LVPO.NEW & NOTEWORTHY Myocardial fibrosis and the resultant increases in LV and myocardial stiffness represent pivotal consequences of chronic pressure overload (PO). In this study, a murine model of cardiac fibrosis induced by PO was used to demonstrate a critical function of SPARC in bone marrow-derived cells that drives cardiac fibrosis and increases in cardiac macrophages.

Regulatory B cells in infection, inflammation, and autoimmunity.

Regulatory B (Breg) cells are characterized by differential expression of CD5 and CD1d in mouse and CD24 and CD38 in human immune systems. The Breg family also includes LAG-3+CD138hi plasma cells, CD1d CD5 CD21 CD23 cells, Tim1, PD-L1, PD-L2, CD200- expressing B cells, and CD39hiKi67+ cells originating from the transitional, marginal zone or germinal centre of the spleen. Breg cells produce IL10 and IL35 and to cause immunosuppression. These cells respond to TLR2, TLR4, and TLR9 agonists, CD40 ligands, IL12p35 and heat shock proteins. Emerging evidence suggests that TLR signalling component Myd88 impacts the modulation of Breg cell responses and the host's susceptibility to infection. Breg cells are found to reduce relapsing-remitting experimental autoimmune encephalomyelitis. However, the Breg-mediated mechanism used to control T cell-mediated immune responses is still unclear. Here, we review the existing literature to find gaps in the current knowledge and to build a pathway to further research.

Breast Cancer Research in the Caribbean: Analysis of Reports From 1975 to 2017.

PURPOSE: Breast cancer is among the leading causes of death resulting from cancer in Caribbean women. Studies examining exogenous and genetically predetermined endogenous risk factors are critical to define breast cancer susceptibility in Caribbean women. The purpose of this systematic review is to assess the existing scientific literature in the last 42 years (1975 to 2017) to describe the body of research generated for the population of this region and determine future research directions. METHODS: We selected published research articles using a combination of definite keyword searches in PubMed. Only articles presenting the Caribbean population as the focus of their research objectives were included in this analysis. RESULTS: Studies on breast cancer in the Caribbean are limited. A majority of publications on Caribbean populations were descriptive, focusing on cancer trends and clinicopathologic factors. High incidence and mortality rates for breast cancer are reported for the region, and there seem to be some differences between countries in the frequency of cases according to age at presentation. A limited number of epidemiologic, behavioral, and genetic and molecular studies were conducted in more recent years. CONCLUSION: A regional strategy for cancer registration is needed for the Caribbean to address possible underestimates of breast cancer incidence. Furthermore, behavioral, molecular, genetic, and epidemiologic investigations of breast cancer are critical to address the concerns related to currently described high incidence and mortality rates in the Caribbean.

Therapeutic Interventions of Tissue Specific Autoimmune Onset in Systemic Lupus Erythematosus.

BACKGROUND: Systemic lupus erythematosus (lupus) is a female predominant autoimmune disease. The autoreactive B cells and T helper cells together are known to develop adverse immune responses in different tissues like kidney, bone, cardiovascular and central nervous system. Progression of disease is associated with deposition of immune complex which initiates tissue damage. The therapy for lupus still includes corticosteroids to reduce allergic manifestations and inflammatory immune responses. Recent observations suggested that, mycophenolate mofetil and cyclophosphamide treatment in combination with corticosteroids have benefit in lupus therapy. METHOD: The prospect of B cell depletion by CD20 targeted monoclonal antibody Rituximab has been demonstrated in lupus patients. The CD52 specific monoclonal antibody Alemtuzumab is another proposition for lupus therapy. The drug Belimumab inhibits B cell activation by altering BAFF/APRIL signal cascade. Recent discovery of the CD22 targeted Epratuzumab also shows therapeutic prospect. The researches on new generation drugs for autoimmune lupus include search for inhibitors of CD40- CD40Ligand interactions, CD86 activation, selective modulation of complement cascades. The choice of inhibitors of transcription factor NF-κBp65 and selective modulators for estrogen receptor alpha are proposed areas of lupus drug discovery research. RESULTS & CONCLUSION: Keeping a close eye on the mechanisms of disease onset, a comprehensive view is provided on recent therapy of systemic lupus erythematosus.

Antigen presentation for priming T cells in central system.

Generation of myelin antigen-specific T cells is a major event in neuroimmune responses that causes demyelination. The antigen-priming of T cells and its location is important in chronic and acute inflammation. In autoimmune multiple sclerosis, the effector T cells are considered to generate in periphery. However, the reasons for chronic relapsing-remitting events are obscure. Considering mechanisms, a feasible aim of research is to investigate the role of antigen-primed T cells in lupus cerebritis. Last thirty years of investigations emphasize the relevance of microglia and infiltrated dendritic cells/macrophages as antigen presenting cells in the central nervous system. The recent approach towards circulating B-lymphocytes is an important area in the context. Here, we analyze the existing findings on antigen presentation in the central nervous system. The aim is to visualize signaling events of myelin antigen presentation to T cells and lead to the strategy of future goals on immunotherapy research.