Study on the role of Lp (a) as an acute phase reactant and on the effects on arterial endothelial and smooth muscle cells.

点击翻译按钮获取中文摘要

Although we have reported transient increases of plasma lipoprotein (a) [Lp (a)] after acute myocardial infarction and surgical operations, the significance of these increases remains unclear. The purpose of the present study was to clarify the physiological roles of Lp (a) in tissue repair.Many samples from inflamed tissues were examined by immunohistochemical techniques. The immunohistochemical features of granulation tissues were characterized by different stages of wound healing. In the first stage, immunoreactivities for anti-apo (a) and-apo B were weak and focal, whereas those for anti-plasminogen and-fibrinogen were strong and widespead on the tissue surface. In the second stage, granulation tissue were covered with loose fibrous connective tissue, and markedly positive staining for Lp (a) was observed closer to the surface, suggesting that Lp (a) may prevent external fibrinolysis. Lp (a) was also found in endothelial cells and the extracellular space of small vessels underlying the fibrous connective. tissues. In the last stage of healing, apo (a) and apo B were not detectable in completely organized tissues. These findings suggest that Lp (a) plays a role in the wound healing.In in vitro study with human umbilical vein endothelial cell (HUVEC), the stimulatory effects of Lp (a) on the migration and proliferation of endothelial cells were observed. These effects were not affected with its isoforms. Anti-bFGF,added in the incubation medium treated with Lp (a), suppressed the Lp (a)-induced HUVEC migrations and proliferations, but the inhibitions were not complete. Pertussis toxin, that blocks the activity of bFGF,also suppressed Lp (a)-induced HUVEC migration. These findings suggest that Lp (a) stimulates the bFGF-mediated HUVEC migration and proliferation, and may promote the angiogenesis.