Canine capillary formation in vitro.

Microvascular endothelial cells derived from canine subcutaneous adipose tissue formed knob-like and tube-like structures in vitro without tumor-conditioned medium or special substrate. The knob-like structures consisted of acidic and basic glycosaminoglycans arranged in order. Knob-like structures were built from cell extrudates and were responsible for capillary lumen formation in vitro. Transmission electron microscopy confirmed the endothelial nature of the cells which expressed extensive phagolysosomal activity.