Publications

Although invasive cytomegalovirus (CMV) disease is uncommon in the era of antiretroviral therapy (ART), asymptomatic CMV coinfection is nearly ubiquitous in HIV infected individuals. While microbial translocation and gut epithelial barrier dysfunction may promote persistent immune activation in treated HIV infection, potentially contributing to morbidity and mortality, it has been unclear whether CMV replication in individuals with no symptoms of CMV disease might play a role in this process. We hypothesized that persistent CMV replication in the intestinal epithelium of HIV/CMV-coinfected individuals impairs gut epithelial barrier function. Using a combination of state-of-the-art in situ hybridization technology (RNAscope) and immunohistochemistry, we detected CMV DNA and proteins and evidence of intestinal damage in rectosigmoid samples from CMV-positive individuals with both untreated and ART-suppressed HIV infection. Two different model systems, primary human intestinal cells differentiated in vitro to form polarized monolayers and a humanized mouse model of human gut, together demonstrated that intestinal epithelial cells are fully permissive to CMV replication. Independent of HIV, CMV disrupted tight junctions of polarized intestinal cells, significantly reducing transepithelial electrical resistance, a measure of monolayer integrity, and enhancing transepithelial permeability. The effect of CMV infection on the intestinal epithelium is mediated, at least in part, by the CMV-induced proinflammatory cytokine IL-6. Furthermore, letermovir, a novel anti-CMV drug, dampened the effects of CMV on the epithelium. Together, our data strongly suggest that CMV can disrupt epithelial junctions, leading to bacterial translocation and chronic inflammation in the gut and that CMV could serve as a target for therapeutic intervention to prevent or treat gut epithelial barrier dysfunction during HIV infection.

BACKGROUND

Immune activation persists despite suppressive antiretroviral therapy (ART) in human immunodeficiency virus (HIV) infection and predicts non-Acquired Immune Deficiency Syndrome (AIDS) comorbidities including cardiovascular disease. Activated platelets play a key role in atherothrombosis and inflammation, and platelets are hyperactivated in chronic HIV infection. Aspirin is a potent inhibitor of platelet activation through the cyclooxygenase-1 (COX-1) pathway. We hypothesized that platelet activation contributes to immune activation and that aspirin would reduce immune activation and improve endothelial function in ART-suppressed HIV-infected individuals.

METHODS

In this prospective, double-blind, randomized, placebo-controlled 3-arm trial of 121 HIV-infected participants on suppressive ART for >48 weeks, we evaluated the effects of 12 weeks of daily aspirin 100 mg, aspirin 300 mg, or placebo on soluble and cellular immune activation markers, flow-mediated dilation (FMD) of the brachial artery, and serum thromboxane B, a direct readout of platelet COX-1 inhibition.

RESULTS

The 300-mg and 100-mg aspirin arms did not differ from placebo in effects on soluble CD14, interleukin (IL)-6, soluble CD163, D-dimer, T-cell or monocyte activation, or the other immunologic endpoints measured. Endothelial function, as measured by FMD, also was not significantly changed when comparing the 300-mg and 100-mg aspirin arms to placebo.

CONCLUSIONS

Aspirin treatment for 12 weeks does not have a major impact on soluble CD14, IL-6, soluble CD163, D-dimer, T-cell or monocyte activation, or FMD, suggesting that inhibition of COX-1-mediated platelet activation does not significantly improve HIV-related immune activation and endothelial dysfunction. Although future studies are needed to further identify the causes and consequences of platelet activation in ART-treated HIV infection, interventions other than COX-1 inhibition will need to be explored to directly reduce immune activation in treated HIV infection.

The impact of real-time electronic monitoring on antiretroviral therapy adherence warrants further study. We conducted an analysis of cohort participants that initially involved standard electronic adherence monitoring (EAM), followed by real-time EAM and home visits for sustained at least 48-h adherence interruptions. Immediately after switching between the two types of EAM, mean adherence among 112 participants increased from 84% to 93% and remained elevated for 6 months (P < 0.001). Real-time EAM is a promising approach for improving adherence.