Our studies have demonstrated that chronic Δ9-tetrahydrocannabinol (THC) administration results in a generalized attenuation of viral load and tissue inflammation in simian immunodeficiency virus (SIV)-infected male rhesus macaques. Gut-associated lymphoid tissue is an important site for HIV replication and inflammation that can impact disease progression. We used a systems approach to examine the duodenal immune environment in 4-6 yr-old male rhesus monkeys inoculated intravenously with SIVMAC251 after 17 mo of chronic THC administration (0.18-0.32 mg/kg, intramuscularly, twice daily). Duodenal tissue samples excised from chronic THC- (N=4) and vehicle (VEH)-treated (N=4) subjects at ~5 mo post-inoculation showed lower viral load, increased duodenal integrin beta 7+ (β7) CD4+ and CD8+ central memory T cells, and a significant preferential increase in Th2 cytokine expression. Gene array analysis identified 6 genes to be differentially expressed in intestinal samples of the THC/SIV animals when compared to those differentially expressed between VEH/SIV and uninfected controls. These genes were identified to have significant participation in 1) apoptosis; 2) cell survival, proliferation, and morphogenesis; and 3) energy and substrate metabolic processes. Additional analysis comparing the duodenal gene expression in THC/SIV vs. VEH/SIV animals identified 93 differentially expressed genes that participate in processes involved in muscle contraction, protein folding, cytoskeleton remodeling, cell adhesion and cell signaling. Immunohistochemical staining showed attenuated apoptosis in epithelial crypt cells of THC/SIV subjects. Our results indicate that chronic THC treatment modulated duodenal T cell populations, favored a pro-Th2 cytokine balance, and decreased intestinal apoptosis. These findings reveal novel mechanisms that may potentially contribute to cannabinoid-mediated disease modulation.

PMID:

 24400995
[PubMed – as supplied by publisher]