Yukari Miyajima

Effect of Total-Body Cold Exposure on Plasma Concentrations of von Willebrand Factor, Endothelin-1 and Thrombomodulin in Systemic Lupus erythematosus Patients with or without Raynaud’s Phenomenon

The effect of total-body cold exposure on plasma concentrations of von Willebrand factor (vWF), endothelin-1 (ET) and thrombomodulin (TM), all of which are considered to be generated from the endothelium, was studied in systemic lupus erythematosus (SLE) patients with and without Raynauds phenomenon. The plasma levels of vWF, ET and TM in SLE patients, irrespective of the presence of Raynauds phenomenon, were significantly higher than in normal controls even before the cold provocation test. After the cold provocation test, plasma levels of vWF and ET were significantly higher in SLE patients with Raynauds phenomenon than in those without and in normal controls. No significant increase in TM was observed in either the SLE patients or the controls. These results suggest that SLE patients, regardless of the presence of Raynauds phenomenon, are in a hypercoagulable state and that this state may be further intensified by cold exposure. Hence, it is concluded that we should consider antithrombotic therapy for SLE patients, especially those with Raynauds phenomenon, to prevent unwanted activation of the coagulation system and possible endothelial damage.

Immunocytochemical localization of thrombomodulin in the aqueous humor passage of the rat eye.

Abstract This report describes the distribution and localization of thrombomodulin (TM) in the rat eye by light and electron microscopic immunocytochemistry. In addition to the endothelium of the entire vasculature, TM was found on the non-vascular structures lining the cavities of the posterior and anterior chambers and the limbus. TM was localized on the basal, lateral, and apical plasma membranes of the inner and outer ciliary epithelium, and the posterior iris epithelium in which there was no polarized expression of TM. In the anterior chamber, TM was localized on the luminal surface of the corneal endothelium, but was negative on the anterior border layer of the iris, which is composed of a discontinuous layer of fibroblasts and collagen fibers. Thus, TM was present at sites of cell-to-cell contact. TM was also present on the endothelia of the trabecular meshwork and the Schlemm’s canal in the limbus. TM was localized not only on the luminal plasma membrane, but also on the cytoplasmic giant vacuoles in the endothelial cells of the Schlemm’s canal. These findings extend the importance of anticoagulant mechanisms to the systems of secretion, circulation, and drainage of the aqueous humor.