Isolation and culture of microvascular endothelium from human adipose tissue.

The study of human endothelial cells in tissue culture has been previously limited to umbilical vein, a large vessel source, and microvascular endothelium from human foreskin, spleen, and adrenal. Microvascular endothelium cultured from these sources have required matrix-coated culture flasks, tumor-conditioned medium, or 50% human serum for growth and subcultivation. To obtain cultures of microvascular endothelium with less stringent growth requirements, human adipose tissue was digested with collagenase and endothelial cells were separated from other stromal elements by sequential filtration and layering cells onto 5% albumin. Using standard medium containing 10% fetal calf serum, these cells grew readily to confluence and survived serial passages. When the cultures were subconfluent, cytoplasmic extensions and a capillary-like morphology were observed. Confluent cultures displayed the "cobblestone" appearance characteristic of other endothelial preparations. Electron microscopy demonstrated the presence of characteristic tight junctions and pinocytotic vesicles. Immunofluorescent staining for Factor VIII was positive, and cultures contained angiotensin-converting enzyme activity. Thus, cultures of human microvascular endothelium were readily obtained from adipose tissue and required only standard medium with 10% serum for growth and subcultivation. This system can be used to study human endothelial cell biology and may prove useful in the study of pathologic states such as diabetic microvasculopathy and tumor angiogenesis.