Elevated Plasma Thymic Stromal Lymphopoietin After Acute Myocardial Infarction

Thymic stromal lymphopoietin modulates T cell response and improves cardiac repair post-myocardial infarction

Background

The inflammatory response is associated with cardiac repair and ventricular remodeling after myocardial infarction (MI). The key inflammation regulatory factor thymic stromal lymphopoietin (TSLP) plays a critical role in various diseases. However, its role in cardiac repair after MI remains uncertain. In this study, we elucidated the biological function and mechanism of action of TSLP in cardiac repair and ventricular remodeling following MI.

Method and Result

Wild-type and TSLP receptor (TSLPR)-knockout (Crlf2-/-) mice underwent MI induction via ligation of the left anterior descending artery. TSLP expression was upregulated in the infarcted heart, with a peak observed on day 7 post-MI. TSLP expression was enriched in the cardiomyocytes of infarcted hearts and the highest expression of TSLPR was observed in dendritic cells. Crlf2-/- mice exhibited reduced survival and worsened cardiac function, increased interstitial fibrosis and cardiomyocyte cross-sectional area, and reduced CD31+ staining, with no change in the proportion of apoptotic cardiomyocytes within the border zone. Mechanistically, reduced Treg cell counts but increased myeloid cell infiltration and an increased ratio of Ly6Chigh/Ly6Clow monocyte were observed in the ani hearts of Crlf2-/- mice. Further, TSLP regulated CD4+ T cell activation and proliferation at baseline and after MI, with a greater impact on Treg cells than on conventional T cells. RNA-seq analysis revealed significant downregulation of genes involved in T cell activation and TCR signaling in the infarcted heart of Crlf2-/- mice compared with their WT counterparts.

Conclusion

Collectively, our data indicate a critical role for TSLP in facilitating cardiac repair and conferring protection against MI, primarily through regulating CD4+ T cell responses, which may provide a potential novel therapeutic approach for managing heart failure after MI.

Emerging Anti-Inflammatory COPD Treatments: Potential Cardiovascular Impacts

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition often complicated by cardiovascular disease (CVD) due to shared inflammatory pathways. This review explores the cardiovascular impacts of emerging anti-inflammatory therapies in COPD. Phosphodiesterase (PDE) inhibitors may offer anti-inflammatory effects with improved lung function but pose potential risks for arrhythmias when PDE3 is inhibited although PDE4 inhibitors reduce cardiovascular events by improving endothelial function and reducing thrombosis. Similarly, p38 mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) inhibitors target COPD-related inflammation and may benefit COPD patients with CVD. p38 MAPK inhibitors reduce cardiac fibrosis, enhance contractility and lower the risk of arrhythmia. PI3K inhibitors target the PI3K/Akt pathway, which drives atherosclerosis and cardiac fibrosis, and thus potentially mitigate both plaque instability and fibrosis. Biologic therapies, including monoclonal antibodies that inhibit IL-5, IL-13/IL-4, thymic stromal lymphopoietin, IL-33, and IL-17A, show promise in reducing exacerbations but require close cardiovascular monitoring due to their immunomodulatory effects. Single-target inhibitors of neutrophil elastase or matrix metalloproteinases show limited efficacy in COPD but may aid cardiovascular patients by stabilizing atherosclerotic plaques through promoting vascular smooth muscle cell proliferation. However, their tendency to degrade the extracellular matrix and attract immune cells may heighten plaque rupture risk, contraindicating use in CVD. Alpha-1 antitrypsin replacement therapy holds promise, potentially reducing COPD exacerbations and providing cardiovascular protection, especially in myocardial injury. Understanding the influence of these innovative therapies on CVD is vital, making it imperative to examine these molecules in COPD patients with CVD at an early stage.