Myocardial and adipose tissue macrophage populations and crown-like structures are associated with cardiovascular and metabolic disease in heart surgery human patients
Abstract
Introduction: Macrophages alone and in the form of crown-like structures (CLS) are a potent source of pro-inflammatory cytokines in adipose tissue and myocardium. Macrophages can contribute to the pathogenesis of obesity-associated disorders including type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD).
We compared M1 and M2 populations and occurence of CLS in the right atrium of myocardium (RA), epicardial (EAT) and subcutaneous (SAT) adipose tissue. Material and Methods: Samples of human tissue were obtained during elective heart surgery (non-obese, n=34; obese, n=24).
The macrophages were visualized by immunohistochemical method. A fraction of EAT and SAT samples was analyzed using flow cytometry.
Results: Pro-imflammatory M1 phenotype of macrophages in adipose tissue was strongly associated with presence of the CLS. Presence of CLS in SAT is associated with all analyzed pathologies, presence of CLS in EAT is associated with obesity and CAD.
SAT macrophages were more frequent in CAD compared to non-CAD patients (p-Value=0.012). RA macrophages were more abundant in obese compared to non-obese patients (p-Value=0.045).
Conclusions: This result demonstrates that the phenotype of macrophages is important for development of pathological processes in the adipose tissue associated with obesity, CAD and T2DM. The hypothesis that therapeutic modulation of SAT and EAT inflammation may represent a target for treatment of obesity.