Antiplatelet drug therapy moderates immune-mediated liver disease and inhibits viral clearance in mice infected with a replication-deficient adenovirus

Abstract

Treatment with a low dose of combined aspirin and clopidogrel, two antiplatelet drugs widely used in humans, markedly reduced the homing of virus-specific cytotoxic T lymphocytes and virus-nonspecific inflammatory leukocytes to the liver of mice acutely infected with a hepatotropic, replication-deficient, lacZ-expressing adenovirus (RAd35). Consequently, aspirin/clopidogrel-induced platelet dysfunction greatly diminished liver disease severity and inhibited viral clearance. Along with the finding that aspirin/clopidogrel caused neither bleeding nor anemia, our results suggest that antiplatelet drugs may be considered to limit excessive liver immunopathology and/or to facilitate the persistence of hepatotropic viral vectors utilized in gene therapy.

FIG. 1.

Aspirin/clopidogrel (Asp/Clo) treatment diminishes liver disease severity. (A) sALT activity (units/liter means ± standard deviations) was measured at the indicated time points in mice (n = 8) that received either diluent or aspirin/clopidogrel and were infected or not with RAd35. Histological analyses of representative lacZ-immunized C57BL/6J mice treated with diluent (B) or Asp/Clo (C) and sacrificed 3 days after RAd35 infection are shown. (B and C) Scale bars, 150 μm.

FIG. 2.

Aspirin/clopidogrel (Asp/Clo) treatment diminishes the intrahepatic number of CTLs and IHLs and inhibits viral clearance. Absolute numbers (means ± standard deviations) of intrahepatic β-Gal96-specific CTLs (A) and IHLs (B) analyzed 3 days after RAd35 infection are shown. Frozen liver sections from representative mice treated with diluent (C or D) and sacrificed 3 days after RAd35 infection were stained for β-galactosidase activity. (C and D) Scale bars, 150 μm. (E) In vitro cytotoxic activity (means ± standard deviations) of β-Gal96-specific CTLs isolated from the same livers shown in panel A (day 3 after RAd35 infection).

FIG. 3.

Aspirin/clopidogrel treatment impairs platelet function but causes neither bleeding nor anemia, and treatment is less efficacious when aspirin or clopidogrel is administered alone. (A) Aggregation of platelets isolated from representative diluent- or aspirin/clopidogrel-treated C57BL/6J mice infected 3 days earlier with RAd35 was measured after arachidonic acid or ADP exposure. Note that while the aggregation of platelets from aspirin/clopidogrel-treated mice was completely abrogated in response to arachidonic acid, the aggregation in response to ADP resulted, as expected, in the formation of aggregates that were smaller and unstable (i.e., they rapidly disaggregated). (B) Hematocrit values (means ± standard deviations; n = 8) were assessed individually 3 days after the indicated treatment. (C) sALT (units/liter) measured 3 days after the indicated treatment is expressed as means ± standard deviations; n = 8.