Ultrastructural morphometric features of human sural nerve endoneurial microvessels.

We studied the morphometric features of 366 transversely sectioned endoneurial microvessels in sural nerves from 50 healthy volunteers (mean age 34.5 +/- 15.8, range 20 to 66 years). Nerves were obtained and processed by the same techniques and standards used to study biopsied nerves from patients with neuropathy. Endothelial area, basement membrane area, number of endothelial nuclei and junctions, and number of periendothelial nuclei all increase significantly with vessel size as judged by mural area. Periendothelial cell coverage of endothelial perimeter does not correlate with vessel size. Components of endoneurial microvessels, specifically the area containing basement membrane, do not change significantly with age. The present report provides a detailed characterization of the ultrastructural features of endoneurial microvessels with age in humans and provides optimal reference values for study of microvessel pathologic changes in disease.