Pathophysiology of septic shock and implications for therapy

Current knowledge about the pathophysiology of septic shock is reviewed, and biotechnology-based therapies under development are discussed. Patients with septic shock begin their clinical course with leukocytosis, fever, tachycardia, tachypnea, and organ hypoperfusion; shock ensues as immunologic and vasoactive mediators produce hypotension. There are many metabolic and cardiovascular responses, and single- or multiple-organ failure is common. Patients may experience adult respiratory distress syndrome. A multitude of endogenous and exogenous factors have been linked to the pathophysiology of sepsis and septic shock, including (1) endotoxin from gram-negative bacteria, (2) peptidoglycan and exotoxins from gram-negative bacteria, (3) endotoxin-binding proteins and receptors, (4) bactericidal proteases, (5) exotoxins from gram-positive bacteria, (6) acute-phase proteins and proteases, (7) cytokines, (8) arachidonic acid metabolites, (9) complement, (10) beta-endorphin, (11) histamine, (12) stimulation of intrinsic and extrinsic coagulation pathways and proteases, and (13) endothelium-derived factors and adhesion molecules. Molecular entities and strategies under development to combat septic shock include monoclonal antibodies to endotoxin, active immunization with lipid-A analogues, bactericidal permeability-increasing protein, interleukin inhibitors, and inhibitors of tumor necrosis factor-alpha. Successful treatment of septic shock will probably require a combination of agents, including antimicrobials. An ideal goal for biotechnology in the area of septic shock is to prevent invading pathogens from overstimulating the host's immune system and to systematically eliminate those pathogens. Biotechnology is opening new avenues to the treatment of septic shock.