The cardiovascular system in diabetes
The cardiovascular system allows blood to circulate through the body delivering nutrients and oxygen, maintaining body temperature and overall homeostasis. Depending on the size of the vessels, the cardiovascular system is divided into microcirculation and macrocirculation, which are characterised by distinct autoregulatory mechanisms yet interconnected physiology and anatomy. Additionally, these circuits cross-talk by haemodynamic (pressure and flow) and neurohumoral factors. In case of pathology, adaptive mechanisms are in place, which respond accordingly to avoid damage. If these mechanisms fail, then pathological signals are transduced between the two circuits, leading to extensive dysfunction. The primary objective of the EU-funded MMC project was to delineate the vascular and haemodynamic cross-talk between the microcirculation and macrocirculation in different human tissues. Given the association of diabetes and cardiovascular disease, MMC researchers focused their work on individuals with insulin resistance. Over 1 500 individuals with and without diabetes, aged between 40 and 75 years and living in the Netherlands, were recruited in an observational study. Extensive phenotyping of their microcirculation and macrocirculation vessels and attributes was performed. The data from the MMC study alongside meta-analysis of other studies supported the coupling of the two vascular circuits. It further indicated that increased pressure pulsatility is a sign of macrocirculation ageing due to physiological or diabetes-related causes. In addition, macrocirculation dysfunctions are linked to damaged microcirculation in various organs. In diabetes, adaptive or maladaptive mechanisms cause greater arterial stiffness and pressure pulsatility. Skin microvascular function was an exception to these observations as it remained unaffected by large arteries' stiffness or diabetes. Delineating the mechanisms by which vascular circuits adapt to pathological signals is of outmost importance for understanding how cardiovascular disease develops. From a clinical perspective, the MMC information is anticipated to improve early prevention and management of cardiovascular disease.
Keywords
Cardiovascular system, diabetes, microcirculation, macrocirculation, insulin resistance
