Regions of the human renal artery: histomorphometric analysis.

The renal artery is frequently involved in the pathogenesis of vasculorenal diseases, and it is a target in kidney surgery and therapeutic techniques for refractory hypertension. However, few detailed structural studies on the human renal artery have been conducted. Using histocytochemistry, immunohistochemistry, and quantitative image analysis, the wall thickness, structure, smooth muscle cells, extracellular matrix, and proportion of elastic tissue in the tunica media of main human renal arteries were used estimated. Ninety-six tissue samples were collected from sections of the right and left main renal arteries. The results showed that the renal artery changed from an elastic vessel in its proximal segment to a muscular artery in its distal part. A critical characteristic of the renal artery was the presence of longitudinal smooth muscle cell formations in the tunica adventitia of middle and distal segments but not in the proximal part of the artery. In addition, the tunica adventitia of the renal artery showed a rich vascularization and the presence of numerous nerves profiles. The artery's regional structural and morphometric features explain that a particular arterial pathology is more frequent in a specific vessel sector than in others. In addition, those characteristics could determine a different therapeutic response attending to the arterial sector.