By definition, the Endothelial Cells comprise a layer of cells that provide a friction-reducing lining in lymph vessels, blood vessels, and the heart. In other words, Endothelium refers to cells that line the interior surface of blood vessels and lymphatic vessels. Realistically, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Significantly, it is a thin layer of simple, or single-layered, squamous cells called the endothelial cell.
In the first place, endothelial or rather endothelium cells release substances that control vascular relaxation and contraction. As well as enzymes that control blood clotting, immune function, and platelet (a colorless substance in the blood) adhesion. Important to realize that; acute smoking significantly impairs vessels’ natural ability to relax, or vasodilate. However, red wine, with or without alcohol, decreases the harmful effect of smoking on the endothelium. See other related Red Wine Benefits to your General Health.
Endothelial cells structure
The endothelium refers to the “container” in which blood is transported. Simply put, the walls of the blood vessels. The vascular endothelium cells consist of polygonal cells forming a continuous layer that line the vessel walls. The endothelium interacts with all vascular tissues in the body. However, the precise structure and function of the endothelium vary in different organs.
Major Endothelial cells function
As can be seen, the Endothelial cells release substances that control vascular relaxation and contraction. As well as enzymes that control blood clotting, immune functioning, and blood platelets adhesion. In general, the endothelium can be divided up into three distinct functional surfaces. Including;
- The non-thrombogenic luminal surface to the blood and its constituents;
- A cohesive junctional surface that modulates the passage of molecules and cells;
- An adhesive abluminal surface capable of interacting with subendothelial structures and perivascular tissues.
The endothelium has multiple functions that can be briefly summarised as follows:
1. Selective Barrier
The endothelium is a selectively permeable barrier. Meaning that it allows certain substances to pass through it while preventing others from passing. Therefore, it helps regulate both immune and inflammatory responses.
2. Transport Utility
Several transendothelial transport mechanisms are thought to exist. The main mechanisms are intercellular clefts and pinocytosis.
3. Angiogenesis (formation of new blood vessels)
Angiogenesis is the formation of new blood vessels and is particularly important in the development of the embryo, where the formation of initial vasculature is critical to the growth of the embryo beyond a few millimeters. Further understanding of how blood vessels grow and develop is also useful in cancer treatment research.
4. Vascular repair
The endothelium composite of endothelial cells is normally a slow-growing tissue. However, this growth rate increases in an area where blood flow is turbulent and in patients with hypertension. When damaged, any exposed subendothelium (the layer directly beneath the endothelium) is covered by adjacent endothelial cells within 30 minutes.
Not only are endothelial cells mobile, but they are also capable of phagocytosis. Remarkably the biological and scientific process of ingesting substances including bacteria. Clinically, the successful revascularization of grafts and sterns is only possible because of these remarkable regenerative powers.
It is essential that blood does not normally clot in the vasculature, and this attribute is dependent on an intact endothelium which has an anticoagulant surface. Paradoxically, blood is required to clot, in a controlled fashion, if a vessel is damaged. Thromboregulation therefore also contributes to repair mechanisms and involves an endothelial expression of cells and molecules associated with coagulation.[caption id="attachment_15919" align="aligncenter" width="1076"] Blood Platelet adhesion to subendothelium, aggregation, and further platelet recruitment culminate in hemostatic plug formation. In particular, accompanied by the consolidating effect of fibrin deposition on and between platelets.[/caption]
These include vasodilators (causing the vessels to dilate) such as nitric oxide and powerful vasoconstrictors (causing the vessels to constrict) such as endothelin.
Endothelial cells express and/or release a wide variety of other molecules including growth factors, enzymes, adhesion molecules, and other receptors.
8. Immune system
At the same time, the endothelial cells normally express the major (ABO) blood groups and Class I (HLA-A, B) histocompatibility antigens. On stimulation by immune cells such as T cells, endothelial cells also express Class II (Ia) histocompatibility antigens and can act as antigen-presenting cells.[caption id="attachment_15918" align="aligncenter" width="1000"] The only way to detect that arteries are vulnerable to atherosclerosis is to assess endothelial function. This is a test of the endothelial cells that line all the arteries in the body.[/caption]
Endothelial Cells Dysfunction
If you have been doing any reading about cardiovascular disease lately, or if you have had a recent talk with your doctor about preventing or treating heart disease, you may have encountered the term “endothelial dysfunction.” The concept of endothelial dysfunction has become important in recent years to our understanding of many cardiovascular conditions, including coronary artery disease (CAD), hypertension, microvascular angina (cardiac syndrome x), diastolic dysfunction, and others.
Dysfunction is defined as the failure of the endothelial cells to respond normally to stimulation, which can leave the artery walls unprotected and plaque can begin to accumulate as a result. This foreshadows the beginning of atherosclerosis. Monitoring endothelial function is therefore critical to assess present and future risk of vascular disease.
Healthy Endothelial Cells
Healthy endothelial cells release nitric oxide (NO), which is responsible for most of the protective functions of these cells in the artery. See other related Key Early Detection of failing endothelium cells.
In conclusion, endothelium possesses many diverse and critical functions in our bodies. As a matter of fact, there has developed an important appreciation of the possible consequences of endothelial cells dysfunction. Including;
- changes affecting structure
- permeability and the regulation of coagulation
- inflammation and vasomotor activity.
As a matter of fact, endothelium helps mediate cardio-protectant effects of physical exercise. In reality, with increased physiological blood flow promoting endothelial cell health. See other related Medical Health & Physical Fitness professionally written Blog Articles.]]>