Figure 1

Schematic representation of microcirculation. In a steady state, the arterial blood flow moves through the capillaries, where it’s deoxygenated before reaching the post-capillary venule. The lymphatic drainage from the interstitial space is reduced and there is a dynamic balance between the formation and the elimination of the interstitial fluid (left). When inflammation is produced, the arterial blood flow can’t be deoxygenated, firstly because the epithelium is necrosed and, secondly because the capillaries are also necrosed and/or obstructed. Arterial blood flow bypass through metaarteriolas prevents the post-capillary vein from being exposed to high oxygen levels. In addition, lymphatic flow gains an unusual prominence (middle). The inflamed interstitium could be represented as surrounded by the different types of endothelium that make up microcirculation, as an “endothelial egg”. The venous and lymphatic endothelium acquire higher extension and functionality since the molecular and cellular exchange between the inflamed interstitium and the rest of the body, that is the host, is produced through them. A: artery; BCE: blood capillary endothelium; C: capillary; E: epithelium; HEVE: high endothelial venule endothelium; I: interstitium; L: lymphatic; LE: lymphatic endothelium; Leu: leukocytes; MA: meta-arteriole; NE: necrosed epithelium; PCVE: postcapillary venule endothelium; SC: stem cell.