Effect of prostaglandin E in multiple experimental models. VII. Effect on resistance to sepsis

Clinical significance of the alterations of plasma prostaglandin E2 (PGE2) in severely burned patients

Agar gel single diffusion and radio immunological analyses were employed to determine the levels of serum C3c, C4, IgA, IgM, IgG and plasma PGE2 in 24 severely burned patients. The results were compared with the development of postburn immunosuppression, severe infection and MOF. There were marked decreases in serum C3c, C4 and Ig, which were especially marked in patients with MOF. Furthermore, plasma PGE2 decreased markedly in patients with MOF and/or severe systemic infection. The results suggest that the decrease of deficiency in plasma PGE2 was closely related to the immunosuppression and the development of severe systemic infection and/or MOF, which supported the hypothesis that PGE2 might play a role in immunoprotection, but not immunosuppression, in burned patients.

Passive transfer of poly-(1-6)-beta-glucotriosyl-(1-3)-beta-glucopyranose glucan protection against lethal infection in an animal model of intra-abdominal sepsis

Previous studies have established the efficacy of soluble polymers of poly-(1-6)-beta-glucotriosyl-(1-3)-beta-glucopyranose (PGG) glucan, a biological-response modifier, in protecting against mortality associated with experimentally induced peritonitis in a rat model. PGG glucan-treated animals showed increases in total leukocyte counts and enhanced bacterial clearance from blood. To further explore the mechanisms) by which this agent confers protection, studies were performed to examine whether protection could be transferred from PGG glucan-treated animals to naive recipients via spleen cells (SC), SC lysates, or serum. Passive-transfer experiments indicated that the responsible factor(s) was transferable by whole SC and SC lysates, as well as by peripheral leukocytes or serum from animals treated with PGG glucan. The transferable factor(s) was resistant to pronase and trypsin digestion, was heat stable at 56 or 80 degrees C, and was not removed by NH4SO4 precipitation. The protective effect of PGG glucan was abrogated by treatment with indomethacin, a potent inhibitor of prostaglandin synthesis. Administration of a purified prostaglandin extract from the sera of PGG glucan-treated animals protected against mortality in the peritonitis model. Furthermore, treatment of rats with exogenous synthetic prostaglandin E2 also conferred protection against mortality. These results suggest that the protective effect exhibited by PGG glucan in the rat peritonitis model is mediated, at least in part, by prostaglandins.

Effect of PGE in multiple experimental models. IX: In vivo effects of PGE on immune response of leucocytes to wounds

There have been conflicting results obtained when comparing the in vitro with in vivo effects of prostaglandin E (PGE) on immune function. The in vitro studies have demonstrated immune suppression with PGE administration while the in vivo studies demonstrated improved survival when utilizing infected models. To attempt to resolve this discrepancy, we evaluated the in vivo effect of PGE on host immune function utilizing multiple rat models. PGE was found to have no effect on the ability of leucocytes to infiltrate a sponge matrix wound over a 2-week period of study. PGE also failed to alter the percentage of T-lymphocyte subset populations infiltrating the sponge matrix model. There was noted to be no effect of PGE on the ability of neutrophils to chemiluminescence, or on metabolic function of lymphocytes. In conclusion, PGE does not appear to have immunosuppressive properties when studied using certain in vivo models.

The immunologic response to thermal injury

Thermal injury is associated with altered immune defense. Extensive and deep thermal injuries lead to depressed immune defense function with both cellular and humoral defense affected. There is an intricate interaction between various components of the immune system. The altered specific immune response is seen as a depressed ability to produce active rosette-forming cells. Depressed stimulation of lymphocyte proliferation as well as the mixed lymphocyte response have also been recorded following burns. These effects are modulated by the release of kinins, prostaglandins, anaphylatoxins, superoxides, and leukotrienes, all of which can influence the inflammatory response following thermal injury. The humoral immunity is altered as seen by decreased levels of immunoglobulins, activation of complement with release of anaphylatoxins, and formation of membrane attacking complexes leading to inflammation and cytolysis. The immune response to burns is also affected by factors other than this injury, such as nutrition or diseases such as diabetes mellitus or disorders of the lymphoproliferative type. The immune response is also influenced by some drugs used for other reasons such as steroids, chemotherapeutic agents, and topical agents used for burn wound care. The immune reaction to a burn is also influenced by the additive effect of superimposed infections. Removal of injured tissue without the need for extensive transfusion will improve the ability of the burned patients to use their immune defense system in a fruitful way.