Endothelium II: inflammatory response

Inflammation is the reaction of the body to injury. Acute inflammation is an important component in the healing of tissue and the initiation of the immune response. Once initiated, the inflammatory response is a complex cascade of processes and the endothelium is active throughout these processes. Chronic inflammation is where exacerbation of the inflammatory response has occurred and further tissue damage ensues. The inflammatory response involves the inflammatory cells (leukocytes), the endothelium and smooth muscle cells and various products produced by them. Initially, leukocyte recruitment and adherence to the endothelium occurs. Activated leukocytes adhere to the endothelium via cell-adhesion molecules and this is followed by transmigration of the leukocyte through the wall of the blood vessel and finally migration towards the site of injury or infection. Cytokines play important roles in the inflammatory process; some are pro-inflammatory and other anti-inflammatory and a balance is required for maintaining control of the inflammatory process. A pro-inflammatory state can alter the function of the endothelium (e.g. homeostasis can change and the endothelium will become predominately pro-coagulant). The inflammatory response is a necessary and required part of wound healing and, when it is maintained as a regulated and orchestrated response, it repairs structural and functional aspects of the injured tissue. Thereby, it can aid in the recovery of a patient after surgery. However, excessive stimulation of the inflammatory process can aggravate tissue damage.