Heart failure in HIV infection: focus on the role of atherosclerosis.

PURPOSE OF REVIEW: Since the advent of highly active antiretroviral treatment, accelerated atherosclerosis resulting in coronary artery disease (CAD) has become an area of increasing concern among patients infected with HIV. As CAD has replaced myocarditis and opportunistic infection as the most common cause of heart failure in this population, it is necessary to re-evaluate the specific risks of cardiovascular disease in HIV-infected patients taking into consideration the processes driving atherogenesis. RECENT FINDINGS: Recent data illustrating that atazanavir is not associated with an increased risk of CAD argue against a class-wide association of protease inhibitors in HIV treatment and adverse cardiovascular outcomes. C-C chemokine receptor-type 5 has been identified as a potential target for pharmacological therapy to manage the process of atherosclerosis while simultaneously having an antiretroviral effect. Additionally, as the use of statins has recently been associated with new-onset diabetes in the general population, further investigation of this risk in HIV-infected patients is necessary. SUMMARY: HIV-infected patients have an increased risk of CAD and subsequently heart failure. This is likely because of a confluence of several factors including: conventional risk factors, HIV-specific processes driving inflammation, coagulatory pathway and endothelial dysfunction. The benefits of antiretroviral drugs in terms of overall survival rates outweigh the risks of dyslipidemia. The focus of the management of cardiovascular risk remains in the domains of primary and secondary prevention. More accurate risk stratification, which accounts for HIV-specific risk factors, is now increasingly warranted.

Characterizing tumor-promoting T cells in chemically induced cutaneous carcinogenesis.

There is a longstanding but poorly understood epidemiologic link between inflammation and cancer. Consistent with this, we previously showed that alphabeta T cell deficiency can increase resistance to chemical carcinogenesis initiated by 7,12-dimethylbenz[a]anthracene and promoted by phorbol 12-myristate 13-acetate. This provoked the hypothesis that alphabeta T cell deficiency removed T regulatory cells that limit the anti-tumor response or removed a specific tumor-promoting (T-pro) T cell population. Here we provide evidence for the latter, identifying a novel CD8(+) subset that is a candidate for T-pro cells. We demonstrate that CD8 cell-deficient mice show substantially less tumor incidence and progression to carcinoma, whereas susceptibility is restored by CD8(+) cell reconstitution. To characterize the putative T-pro cells, tumor-infiltrating lymphocytes were isolated from normal and CD4(-/-) mice, revealing an activated population of T cell receptor alphabeta(+)CD8(+)CD44(+)CD62L(-) cells expressing the inflammatory mediators IFNgamma, TNFalpha, and cyclooxygenase-2, but deficient in perforin, relative to recirculating cells of equivalent phenotype. This novel population of CD8(+) T cells has intriguing similarities with other lymphocytes that have been associated with tissue growth and invasiveness and has implications for inflammation-associated carcinogenesis, models of cancer immunosurveillance, and immunotherapeutic strategies.

Folate deficiency and ionizing radiation cause DNA breaks in primary human lymphocytes: a comparison.

DNA double-strand breaks, the most serious DNA lesion caused by ionizing radiation, are also caused by several vitamin or mineral deficiencies, such as for folate. Primary human lymphocytes were either irradiated or cultured at different levels of folate deficiency to assess cell proliferation, apoptosis, cell cycle, DNA breaks, and changes in gene expression. Both radiation and folate deficiency decreased cell proliferation and induced DNA breaks, apoptosis, and cell cycle arrest. Levels of folate deficiency commonly found resulted in effects similar to those caused by 1 Gy of radiation, a relatively high dose. Though both radiation and folate deficiency caused DNA breaks, they affected the expression of different genes. Radiation activated excision and DNA double-strand break repair genes and repressed mitochondrially encoded genes. Folate deficiency activated base and nucleotide excision repair genes and repressed folate-related genes. No DNA double-strand break repair gene was activated by folate deficiency. These findings suggest that a diet poor in folate may pose a risk of DNA damage comparable to that of a relatively high dose of radiation. Our results also suggest that research on biological effects of low-dose radiation should take into account the nutritional status of the subjects, because folate deficiency could confound the effects of low-dose radiation.