Endogenous endothelin in a rat model of acute colonic mucosal injury.
Endothelin (ET) is involved in various biologic activities in non-vascular and vascular tissues. While ET has some significant effects on gastrointestinal functions, the possible role of endogenous ET in the host response to mucosal injury has not been well clarified.
The present study describes an investigation of the effects of an endothelin A receptor antagonist, BQ-123, on lactate dehydrogenase (LDH), mucus and albumin flux into the perfusate in a rat model of acute colonic injury, induced by acetic acid perfusion. The present study also examined localization of ET in damaged rat colons by using immunohistochemistry.
A 4% acetic acid treatment induced mild mucosal damage of perfused rat colon and increased LDH as well as albumin and protein-bound hexose release into the perfusate. Pretreatment with BQ-123 significantly reduced LDH activity and protein-bound hexose concentration in the perfusate and delayed the reduction of albumin leakage from damaged mucosa. Vascular endothelial, neural and surface epithelial cells of the colon showed strong ET-like immunoreactivity. Mucosal damage markedly influenced ET expression by epithelial cells. Mild mucosal damage decreased the ET expression by surface epithelial cells while moderate mucosal damage induced a mosaic location of ET-positive epithelial cells in the crypt. Severe mucosal damage abolished the ET expression by epithelial cells.
Endothelin may play a role in the host response to acute mucosal damage. Mucosal ET production is significantly affected by mucosal injury.
Available from: Kerstin Lang
- "Endothelin is primarily produced in the endothelium in response to stress mediators such as norepinephrine . It contributes to the regulation of blood pressure by vasoconstriction , but is also known to play a role in the regulation of gastrointestinal function   . Endothelin- 1 is overexpressed in Kaposi's sarcoma lesions and promotes invasiveness as well as tumor growth in an autocrine fashion . "
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ABSTRACT: A leading cause of death, cancer remains the bane of modern society and one of the most challenging research fields. Cancer is initially a localized disease that can be often treated well at a very early stage. However the vast majority of cancer deaths result from a pernicious progression of the disease, the development of distant metastases. It must therefore be a pressing research goal to focus on the pharmacological prevention of metastasis development. This review summarizes the current understanding of the cellular and molecular mechanisms of metastasis development, and suggests possible approaches for its inhibition.
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