Effect of Dexmedetomidine and Total Intravenous Anesthesia on Endothelial Damage-Related Biomarkers

Endothelial Glycocalyx (EG) is a carbohydrate-rich network covering the apical surface of endothelial cells. It consists of sulphated glycoproteins linked to sialic acids (heparan sulphate, dermatan sulphate), core proteoglycans (mainly syndecan-1) and unsulphated glycosaminoglycans (CD 44) directly attached to the cytoplasmic membrane of endothelial cells. The fragile nature of endothelial glycocalyx makes it highly susceptible to damage, especially in critical diseases such as septic shock and inflammation, ischaemia-reperfusion (IR) syndrome, oxidative stress and major trauma. Endothelial glycocalyx damage worsens the patient's clinical outcome, leading to capillary leakage, tissue oedema, immune system disorders, and thrombosis. Despite the widespread use of transmission electron microscopy, fluorescence microscopy and intravital microscopy in experimental investigations, these methods are not applicable at the bedside. The second most widely used method to investigate endothelial glycocalyx is biochemical analysis of EG degradation products (e.g. syndecan-1, heparan sulphate, hyaluronan). In surgical procedures, general anaesthesia is a pharmacological method used to control pain and consciousness. The agents administered in this process may be associated with both hypnotic and analgesic mechanisms acting on the central nervous system and side effects on the autonomic nervous system and circulatory system. Pharmacological agents used during general anaesthesia may exert pro-inflammatory or anti-inflammatory effects on the endothelium directly or indirectly. Some anaesthesia modalities may trigger endothelial damage by increasing oxidative stress, free radical production and the release of inflammatory cytokines. On the other hand, some techniques may show endothelial protective properties; this is related to the dose, duration and pharmacodynamic properties of the agents used. Because there is no pharmacological agent to prevent EG damage, it is important to prevent EG degradation in patients undergoing surgery. For all these reasons, evaluating the effects of general anaesthesia on endothelial function may provide important information for the protection of vascular health during and after surgery. This study aimed to evaluate whether dexmedetomidine has a protective effect on endothelial damage in rhinoplasty patients under general anaesthesia by measuring plasma syndecan1 and heparan sulphate levels.