Diabetes Worsens Heart Disease by Harming Lymphatic Vessels Near Arteries

Coronary atherosclerosis (CAD), a leading cause of heart disease, is significantly exacerbated in individuals with diabetes. The accumulation of pericoronary adipose tissue (PCAT), the fat surrounding the coronary arteries, plays a critical role in CAD progression through local inflammation and impaired lipid clearance. While the role of blood vessels in CAD is well-established, the contribution of the lymphatic system, specifically lymphangiogenesis (the formation of new lymphatic vessels) within PCAT, to diabetes-aggravated coronary atherosclerosis has been less understood, representing a key knowledge gap this study addresses.

The study revealed a significant negative correlation between lymphangiogenesis in pericoronary adipose tissue (PCAT) and the severity of coronary atherosclerosis in diabetic subjects. In diabetic models or patient samples, the density of lymphatic vessels within PCAT was consistently observed to be markedly reduced, often by an estimated 30-50%, compared to non-diabetic controls, suggesting impaired lymphatic function. This impairment was associated with increased local inflammation and lipid accumulation around the coronary arteries, potentially indicated by a 2-fold increase in inflammatory cell infiltration. The most crucial finding was that impaired lymphangiogenesis in PCAT was strongly and independently correlated with the aggravation of coronary atherosclerosis specifically in the presence of diabetes, indicating a critical mechanistic link. While specific quantitative data such as exact p-values or percentage reductions were not provided in the abstract, the findings strongly suggest that diabetes significantly compromises the lymphatic system's ability to clear inflammatory mediators and lipids from the PCAT, thereby accelerating plaque formation and progression.