Cell adhesion or cell adhesiveness is the adherence of cells to each other or to other organic structures. This adherence force is one of the essential foundations of organic life, as it provides for the concrete structure of, for example, the human body.
What is cell adhesion?
Cell adhesion, or cell adhesiveness, is the attachment of cells to each other or to other organic structures. Cells bind to other cells, different substrates, or molecular membranes. In this way, they are anchored in their environment. At the same time, cells also separate themselves from other cell formations, tissues and organs in this way. Cell adhesion also causes weaker bonds to be constantly detached from stronger ones between cells, and a cell association is thus renewed and stabilized. The contacts of the cells with each other lead to mechanical cohesion, they secure the demarcation against existing external media and enable the expansion of direct relationships between cells or cell clumps. For example, new human tissue is formed after surgery, injury, or bone fracture.
Function and task
Cell adhesion also allows individual blood cells to adhere to the inner walls of blood vessels and thus separate from flowing blood. Other blood cells are even able to move along the vessel walls. In this way, cells of the immune system, for example, can reach targeted sites of infection in the body. It is possible that these blood cells can even cross the blood-brain barrier. This protects the brain from pathogens as well as toxins and messenger substances in the blood. Medicine has not yet been able to prove this phenomenon, but it is probably related to some neurological diseases that have not yet been definitively researched. During blood clotting, platelets (thrombocytes) form an adhesive bandage and adhere to each other more or less tightly. The tissue of the skin or any internal organ is nothing more than a large cohesive bandage of cells. The tissue cells are connected by cell adhesion to the proteins of the extracellular matrix. This intercellular substance is composed mainly of connective tissue, which supplies the cells with nutrients and transmits neurological signals.
Diseases and disorders
The development of infectious diseases is equally related to cell adhesion. For example, numerous bacteria enter the body through the mucous membranes in the respiratory tract. They adhere there and in this way enter the human organism, where they then successfully multiply. The bacteria have adapted so well to the molecular structure of the mucous membranes that practically nothing can stop them on this path. Inflammations are also directly related to cell adhesion in the body. They can change the adhesion properties of entire tissue layers by emitting fibrin. This acts like a glue and thus leads to connective tissue-like adhesions that can also affect blood vessels located there. Fibrin is a protein that is actually responsible for blood clotting. However, by triggering the tissue adhesions, it can impair the normal functioning of the affected organs or make it impossible. In these cases, tissues or organs that normally have no connection to each other grow together. An example of processes of this type is the so-called adhesion belly, a scarred cord in the abdominal cavity. It can turn out to be completely harmless as long as the adhesion mainly affects the supporting tissue and not the organ-forming tissue. More serious complications can be caused, for example, by intestinal obstruction, which is also an adhesion in the abdominal cavity. It can lead to a rupture of the intestine, which may be life-threatening. A restriction or even interruption of the blood supply due to an adhesion in the abdominal area is also possible. In the worst case, the affected tissue may die. Surgical intervention would be unavoidable. Adhesions following irregular cell adhesion also frequently occur in the joint capsules, where they lead to massive restrictions in joint function. As it turns out, cell-adhesive adhesions or adhesions are capable of triggering multiple physical complaints or impairments without their cause being clearly identifiable at first.If, for example, the female genital organs are affected, consequences such as pain in the lower abdomen, sexual dysfunction or even infertility may occur. The adhesions can be cut surgically. However, it is common for them to re-form within a shorter period of time after such adhesiolysis. So-called liquid adhesion barriers are used with some success. This can be, for example, a dissolved sugar-like substance applied as an irrigation fluid during a surgical procedure. Research into all the processes associated with cell adhesion is also of great importance for cancer therapy. This mainly concerns the interaction of the vascular endothelium (the inner blood vessel wall) with blood and tumor cells. This provides information about the progression of cancer. The vascular endothelium is a cell formation that acts as a barrier and also a medium of mass exchange between flowing blood and surrounding tissue. As the lining of vessels and vascular branches, the area of the endothelium in the body of an adult human is estimated to be about 5,000 square meters. This is comparable to the dimensions of a soccer field. Under these conditions, the cell-adhesive interactions of the endothelium with leukocytes, platelets and tumor cells have a very large variety and dimension. Inflammatory processes and blood coagulation disorders could be more clearly explained and possibly controlled with a better understanding of these interactions. In addition, appropriate research would make it easier to understand how cancer cells attach to and break through vascular walls and subsequently invade the surrounding tissue structure. If this complicated and complex research is successful, it would be possible in the future to deactivate malignant (malignant) tumor cells under certain circumstances.
