[Microvascular disorders of adipose tissue]

The microcirculation of adipose tissue is poorly understood either because of the absence of histological documents or because they fail to explain pathological conditions. However, disturbances of blood flow and parietal lesions of the microvessels are the basis for these disorders. Although we speak of disturbances of the vascular control mechanisms, these mechanisms are poorly understood and although we speak of arteriovenous short-circuits, the existence of these lesions has not been proven. In fact, classically, the circulation in the dermis and hypodermis is assured by a meshwork of arterioles, venules and capillaries, but biopsies of lateral and anterior regions of the thigh have demonstrated "block devices" in the walls of small arteries and arterioles which are able to regulate the rate of blood flow towards the capillary bed. Following contraction of these devices, the vascular lumen dilates, ensuring free circulation and when they relax, the lumen closes, resulting in decreased or no blood flow. These smooth muscle devices within the arterial wall resemble small cushions in the small arteries and more or less pedunculated polyps in the arterioles, either simple or fissured in the form of an elephant's trunk with a safety valve effect, arranged either in a single column or in two columns face to face. This provides evidence for the particularly disturbed vasculo-tissue inter-relations observed in venous insufficiency.(ABSTRACT TRUNCATED AT 250 WORDS)