Adenosine A(2A) receptor activation reduces recurrence and mortality from Clostridium difficile infection in mice following vancomycin treatment

BACKGROUND: Activation of the A(2A) adenosine receptor (A(2A)AR) decreases production of inflammatory cytokines, prevents C. difficile toxin A-induced enteritis and, in combination with antibiotics, increases survival from sepsis in mice. We investigated whether A(2A)AR activation improves and A(2A)AR deletion worsens outcomes in a murine model of C. difficile (strain VPI10463) infection (CDI). METHODS: C57BL/6 mice were pretreated with an antibiotic cocktail prior to infection and then treated with vancomycin with or without an A(2A)AR agonist. A(2A)AR(-/-) and littermate wild-type (WT) mice were similarly infected, and IFNγ and TNFα were measured at peak of and recovery from infection. RESULTS: Infected, untreated mice rapidly lost weight, developed diarrhea, and had mortality rates of 50-60%. Infected mice treated with vancomycin had less weight loss and diarrhea during antibiotic treatment but mortality increased to near 100% after discontinuation of antibiotics. Infected mice treated with both vancomycin and an A(2A)AR agonist, either ATL370 or ATL1222, had minimal weight loss and better long-term survival than mice treated with vancomycin alone. A(2A)AR KO mice were more susceptible than WT mice to death from CDI. Increases in cecal IFNγ and blood TNFα were pronounced in the absence of A(2A)ARs. CONCLUSION: In a murine model of CDI, vancomycin treatment resulted in reduced weight loss and diarrhea during acute infection, but high recurrence and late-onset death, with overall mortality being worse than untreated infected controls. The administration of vancomycin plus an A(2A)AR agonist reduced inflammation and improved survival rates, suggesting a possible benefit of A(2A)AR agonists in the management of CDI to prevent recurrent disease.