Misoprostol impairs female reproductive tract innate immunity against Clostridium sordellii.
Fatal cases of acute shock complicating Clostridium sordellii endometritis following medical abortion with mifepristone (also known as RU-486) used with misoprostol were reported. The pathogenesis of this unexpected complication remains enigmatic. Misoprostol is a pharmacomimetic of PGE(2), an endogenous suppressor of innate immunity. Clinical C. sordellii infections were associated with intravaginal misoprostol administration, suggesting that high misoprostol concentrations within the uterus impair immune responses against C. sordellii. We modeled C. sordellii endometritis in rats to test this hypothesis. The intrauterine but not the intragastric delivery of misoprostol significantly worsened mortality from C. sordellii uterine infection, and impaired bacterial clearance in vivo. Misoprostol also reduced TNF-alpha production within the uterus during infection. The intrauterine injection of misoprostol did not enhance mortality from infection by the vaginal commensal bacterium Lactobacillus crispatus. In vitro, misoprostol suppressed macrophage TNF-alpha and chemokine generation following C. sordellii or peptidoglycan challenge, impaired leukocyte phagocytosis of C. sordellii, and inhibited uterine epithelial cell human beta-defensin expression. These immunosuppressive effects of misoprostol, which were not shared by mifepristone, correlated with the activation of the G(s) protein-coupled E prostanoid (EP) receptors EP2 and EP4 (macrophages) or EP4 alone (uterine epithelial cells). Our data provide a novel explanation for postabortion sepsis leading to death and also suggest that PGE(2), in which production is exaggerated within the reproductive tract during pregnancy, might be an important causal determinant in the pathogenesis of more common infections of the gravid uterus.
Aronoff
David M
DM
Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, MI 48109, USA. daronoff@umich.edu
Hao
Yibai
Y
Chung
Jooho
J
Coleman
Nicole
N
Lewis
Casey
C
Peres
Camila M
CM
Serezani
Carlos H
CH
Chen
Gwo-Hsiao
GH
Flamand
Nicolas
N
Brock
Thomas G
TG
Peters-Golden
Marc
M
D000818:Animals; D002460:Cell Line; D003015:Clostridium Infections / Q000276:immunology*; D047989:Paraclostridium sordellii / Q000187:drug effects* / Q000276:immunology* / Q000472:pathogenicity; D004195:Disease Models, Animal; D004716:Endometritis / Q000276:immunology* / Q000382:microbiology* / Q000401:mortality; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000009:adverse effects; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000502:physiology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008808:Mice, Inbred CBA; D016595:Misoprostol / Q000008:administration & dosage / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar; D014774:Virulence / Q000187:drug effects / Q000276:immunology
D007166:Immunosuppressive Agents; D018836:Inflammation Mediators; D016595:Misoprostol