Phagocytic cell functions in sepsis – role and potential therapies of sepsis-induced immunosuppression
OA Version
Citation
Abstract
Globally, sepsis is one of the largest causes of death in acute care units. Even with adequate treatment, severe sepsis affects over 49 million people worldwide and is responsible for approximately 11 million deaths each year. People respond differently to infection, which is evidence that individuals have varying degrees of immune suppression. As a result of a pathogen triggering the Systemic Inflammatory Syndrome (SIRS), sepsis is an immunological condition that is diagnosed based on patterns of temperature, heart rate, respiration, and white blood cell (WBC) count.
Although the pathogenesis of sepsis remains unclear, there is growing evidence that oxidants and antioxidants play a major role. Oxidative stress is defined by elevated intracellular levels of reactive oxygen species (ROS) that cause damage to lipids, proteins, and DNA. Sepsis pathophysiology includes infection by gram negative or positive bacteria, an elevated inflammatory reaction; lower blood pressure that may result in vasodilatory shock; and reduction of oxygen delivery to organs as a response to cell dysfunction. It has been demonstrated that free radicals such as nitric oxide (NO), peroxynitrite (ONOO-), and hydrogen peroxide are involved in these effects. Specifically, it has been demonstrated that hydroxyl radicals play a role.
An extensive network of complicated phagocytic mechanisms is implicated in the development of sepsis. As a result, phagocytosis plays an important function in sepsis and presumably contributes to most clinical phases of the disease. Only a few research studies, however, have particularly investigated and defined the effects of immunosuppression on phagocytic activity during sepsis as a result of the infection. In this paper, I explain the immune response's phagocytic mechanisms that occurs prior to the development of sepsis and identify the features of phagocytosis that may act as a predictive marker for the outcome of the disease. To begin with, I describe some of the most important characteristics of phagocytic processes such as phagocytic main receptors and signaling characteristics. After that, I address the role of phagocytic cell functions during sepsis-induced immunosuppression, as well as some of the research that's been done on the subject recently. Finally, I discuss some of the potential immunosuppressive therapies for septic patients.