Effects of G-CSF on telomere lengths in PBMCs from human immunodeficiency virus-infected patients: results from a randomized, placebo-controlled trial

Global DNA methylation and telomere length as markers of accelerated aging in people living with HIV and non-alcoholic fatty liver disease

Metabolic-dysfunction-associated fatty liver disease (MAFLD) is a comorbidity that generally increases in people living with HIV (PLWH). This condition is usually accompanied by persistent inflammation and premature immune system aging. In this prospective cohort study, we describe a straightforward methodology for quantifying biomarkers of aging, such as DNA methylation and telomere length, in PLWH and in the context of another relevant condition, such as MAFLD. Fifty-seven samples in total, thirty-eight from PLWH and nineteen from non-PLWH participants with or without MAFLD, were obtained and subjected to DNA extraction from peripheral blood mononuclear cells (PBMCs). Global DNA methylation and telomere length quantification were performed using an adapted enzyme-linked immunosorbent assay (ELISA) and qPCR, respectively. The quantification results were analysed and corrected by clinically relevant variables in this context, such as age, sex, and metabolic syndrome. Our results show an increased association of these biomarkers in PLWH regardless of their MAFLD status. Thus, we propose including the quantification of these age-related factors in studies of comorbidities. This will allow a better understanding of the effect of comorbidities of HIV infection and MAFLD and prevent their effects in these populations in the future.

Telomerase and primary T cells: biology and immortalization for adoptive immunotherapy

Telomeres are specialized repeats, present at the end of chromosomes, whose loss during cell division is followed by growth arrest, a central mechanism of replicative senescence in human cells. Telomere length in stem cells is maintained by telomerase, a specialized reverse transcriptase, whose function is to restore shortening telomeres. Unlike most somatic cell types, human T lymphocytes are capable of briefly reactivating telomerase expression at the time of stimulation. Telomerase expression in T lymphocytes is modulated by a variety of external stimuli and by viral infections. However, telomerase reactivation in stimulated, proliferating human T lymphocytes is limited and cannot prevent the ultimate onset of senescence. Ectopic telomerase expression can rescue human and macaque antigen-specific T cells from senescence. Primary T cells have been engineered with telomerase to have substantially extended replicative lifespans without the loss of primary cell functions or malignant transformation. 'Immortal' antigen-specific T-cell lines and clones overexpressing telomerase are an invaluable source of well-characterized quasi-primary T cells for research of T-cell biology and are potentially useful for immunotherapy of cancer and AIDS.

Regulation of telomerase activity by apparently opposing elements

Telomeres, the ends of chromosomes, undergo frequent remodeling events that are important in cell development, proliferation and differentiation, and neoplastic immortalization. It is not known how the cellular environment influences telomere remodeling, stability, and lengthening or shortening. Telomerase is a ribonucleoprotein complex that maintains and lengthens telomeres in the majority of cancers. Recent studies indicate that a number of factors, including hormones, cytokines, ligands of nuclear receptor, vitamins and herbal extracts have significantly influence telomerase activity and, in some instances, the remodeling of telomeres. This review summarizes the advances in understanding of the positive and negative regulation by extracellular factors of telomerase activity in cancer, stem cells and other systems in mammals.

Ongoing trials of immune-based therapies for HIV infection in adults

Highly active antiretroviral therapy (HAART) can significantly alter the clinical course of patients infected with HIV. Unfortunately, effective lifelong HAART may not be a practical or achievable goal because of toxicities, cost, development of viral resistance and patient compliance issues. Immune-based therapies (IBTs) that target the host immune system may serve as rational additions to our current antiretroviral strategies. Investigations into IL-2 have culminated in two large Phase III clinical trials. Multiple therapeutic vaccine candidates are in various phases of investigation. In addition, gene therapy has been proposed as a potential treatment for HIV and Phase I trials are ongoing. Although IBTs are being investigated on many fronts, they remain difficult to study due to a lack of validated surrogate end points.