Glucose-Induced Production of Type IV Collagen from Cultured Human Umbilical Vein Endothelial Cells

Abstract

To study the effect of high glucose concentration on the production of type IV collagen and laminin P₁ from cultured human umbilical vein endothelial cells (HUVEC), we measured type IV collagen and laminin P₁ from HUVEC that were cultured under different conditions of glucose. The amount of type IV collagen in the cultured medium with 30mM D-glucose was significantly higher than in those with 5.6mM D-glucose, 30mM L-glucose or 30 mM mannitol. The increase of type IV collagen in the medium was dependent on the glucose concentration and the incubation time. The amount content of intracellular type IV collagen in the cultured HUVEC was also significantly higher with high glucose concertrations than with low glucose or L-glucose concentrations. No morphological changes were found by phase-contrast microscopy in HUVEC cultued with 5.6mM or 30mM D-glucone for 96 hours. The concentrations of protein in the HUVEC showed no significant differences between the media with 5.6mM D-glucose, 15mM D-glucose, 30 mM D-glucose, 30mM L-glucose or 30mM mannitol.Pulse thymidine incorporation was similar for the cells exposed to 5.6mM, 30m D-glucose or 30mM mannitol. Pulse proline incorporation was significantly higher at high than low glucose concertrations.In contrast, the levels of laminin P₁ in the media cultured with high glucose concentrations were similar to those cultured with 5.6mM or 15mM D-glucose. These results suggest that high glucose concentration may directly affect the production of type IV collagen, and that hypertonicity or non-metabolizable glucose does not contribute to the production of type IV collagen. Increase of type IV collagen may be involved in the development of diabetic microangiopathy.