Glyburide Reduces Bacterial Dissemination in a Mouse Model of Melioidosis

Abstract

Background Burkholderia pseudomallei infection (melioidosis) is an important cause of community-acquired Gram-negative sepsis in Northeast Thailand, where it is associated with a ∼40% mortality rate despite antimicrobial chemotherapy. We showed in a previous cohort study that patients taking glyburide ( = glibenclamide) prior to admission have lower mortality and attenuated inflammatory responses compared to patients not taking glyburide. We sought to define the mechanism underlying this observation in a murine model of melioidosis.MethodsMice (C57BL/6) with streptozocin-induced diabetes were inoculated with ∼6×102 cfu B. pseudomallei intranasally, then treated with therapeutic ceftazidime (600 mg/kg intraperitoneally twice daily starting 24 h after inoculation) in order to mimic the clinical scenario. Glyburide (50 mg/kg) or vehicle was started 7 d before inoculation and continued until sacrifice. The minimum inhibitory concentration of glyburide for B. pseudomallei was determined by broth microdilution. We also examined the effect of glyburide on interleukin (IL) 1β by bone-marrow-derived macrophages (BMDM).ResultsDiabetic mice had increased susceptibility to melioidosis, with increased bacterial dissemination but no effect was seen of diabetes on inflammation compared to non-diabetic controls. Glyburide treatment did not affect glucose levels but was associated with reduced pulmonary cellular influx, reduced bacterial dissemination to both liver and spleen and reduced IL1β production when compared to untreated controls. Other cytokines were not different in glyburide-treated animals. There was no direct effect of glyburide on B. pseudomallei growth in vitro or in vivo. Glyburide directly reduced the secretion of IL1β by BMDMs in a dose-dependent fashion.ConclusionsDiabetes increases the susceptibility to melioidosis. We further show, for the first time in any model of sepsis, that glyburide acts as an anti-inflammatory agent by reducing IL1β secretion accompanied by diminished cellular influx and reduced bacterial dissemination to distant organs. We found no evidence for a direct effect of glyburide on the bacterium.

A Protective Role of Glibenclamide in Inflammation-Associated Injury

“…Studies involved in our review showed that patients who were not pretreated had no obvious changes in blood glucose levels [10–12, 17–19, 22–26, 59]. This finding indicates that the anti-inflammatory effect of glibenclamide is independent of its hypoglycemic effect.…”

Therapeutic Administration of a Monoclonal Anti-Il-1β Antibody Protects Against Experimental Melioidosis

“…Importantly, we previously showed that melioidosis patients taking the antidiabetic drug glyburide (=glibenclamide) have a lower mortality and attenuated inflammatory responses compared with patients not taking glyburide ( 26 ). Using our murine melioidosis model, we found that glyburide acts as an anti-inflammatory agent by reducing IL-1β secretion accompanied by diminished cellular influx and reduced bacterial dissemination to distant organs ( 13 ).…”

“…Experimental melioidosis was induced by intranasal inoculation with 3 or 5 × 10 2 colony-forming units (CFU) of B pseudomallei strain 1026b (a clinical isolate) as described ( 13 ). At 24 and/or 72 h postinfection, mice were euthanized and sacrificed by bleeding from the inferior vena cava, after which organs were harvested.…”

“…In some experiments mouse monoclonal antibody directed against mouse IL-1β (α-IL-1β; 10 μg/g bodyweight) with comparable properties to canakinumab in humans ( 14 ) was administered intraperitoneally at 6 or 24 h postinfection. In addition, selected animals received ceftazidime 600 mg/kg (GlaxoSmithKline, Brentford, England) intraperitoneally twice daily, starting 6 h after inoculation until sacrifice ( 13 ). For survival experiments, mice were observed every 6 h for 11 days and α-IL-1β administration was repeated at day 7.…”

The treatment of melioidosis: is there a role for repurposed drugs? A proposal and review

“…Study of the patients' transcriptome showed reduction of many inflammatory markers (including IL-1), correlating with the effects of the drug's prevention of activation of cryopyrin inflammasome [47]. The benefits of glyburide were also seen in a murine model of infection with reduced bacterial load and inflammation (notably IL-1β) [48]. Another study, however, found that treatment with glyburide worsened disease associated with reducing inflammation [49].…”