In the context of dysfunctional endothelial barriers, what major protein is often lost?

In the context of dysfunctional endothelial barriers, the major protein that is often lost is albumin. Endothelial cells line the blood vessels and are crucial for maintaining vascular integrity and regulating the movement of substances between the bloodstream and surrounding tissues. When the endothelial barrier becomes dysfunctional, it leads to increased permeability, allowing proteins such as albumin to leak out of the bloodstream and into the interstitial space.

Albumin is a key plasma protein that plays several critical roles, including maintaining oncotic pressure, which helps keep fluid within the blood vessels, and serving as a carrier for various substances. Its loss can result in edema and a decrease in the blood's ability to retain fluid, contributing to complications associated with various diseases, such as diabetes and sepsis.

The other options do not have the same association with endothelial barrier dysfunction. Insulin primarily regulates glucose metabolism and is not directly linked to the integrity of endothelial barriers. Hemoglobin is associated with oxygen transport in red blood cells and is not relevant in this context. Fibronectin is a glycoprotein involved in cell adhesion and wound healing but is not the primary protein lost when endothelial barriers fail. Thus, the focus on albumin reflects its critical importance in vascular health and the consequences of its loss due to