Morphological Alterations of Microvasculature and Neoangio- genesis in the Pressure Ulcers Repair in Paraplegics

We performed a comparative study of histological, immunohistochemical and ultrastructural characteristics of blood microvasculature in specimens of pressure ulcers (PU) in paraplegic patients with acute spinal cord injury and in non paraplegic subjects. For immunohistochemical study we stained for cell membrane proteins that are commonly utilized for light microscopic characterization of blood endothelial cells as monoclonal antibodies CD31 and CD34, and for endothelial cell proliferation antigen Ki67. In paraplegics, the morphological and morphometric analysis of perilesional dermal tissues showed numerical capillary reduction, wall thickening and basement membrane changes of microvasculature. In non paraplegic ulcers the perilesional vasculature showed normal morphology. The granulation tissue in PU from paraplegics showed reduction in the number of new vessels and of the proliferating fraction of the endothelial cells if compared to non paraplegic PU. The onset of PU in paraplegics appears to be determined by mechanic factors and by intrinsic alterations of microvasculature such as impairment of angiogenic regulation in wound healing (VEGF and FGF2), and reduction of endothelial proliferation and capillary growth.