In people living with HIV (PLWH) who are failing or unable to access combination antiretroviral therapy (cART), monocytes and macrophages are important drivers of pathogenesis and progression to AIDS. The relevance of the monocyte/macrophage reservoir in PLWH receiving cART is debatable as in vivo evidence for infected cells is limited and suggests the reservoir is small. Macrophages were assumed to have a moderate life span and lack self-renewing potential, but recent discoveries challenge this dogma and suggest a potentially important role of these cells as long-lived HIV reservoirs. This, combined with new HIV infection animal models, has led to a resurgence of interest in monocyte/macrophage reservoirs. Infection of non-human primates with myeloid-tropic SIV implicates monocyte/macrophage activation and infection in the brain with neurocognitive disorders, and infection of myeloid-only humanized mouse models are consistent with the potential of the monocyte/macrophage reservoir to sustain infection and be a source of rebound viremia following cART cessation. An increased resistance to HIV-induced cytopathic effects and a reduced susceptibility to some antiretroviral drugs implies macrophages may be relevant to residual replication under cART and to rebound viremia. With a reappraisal of monocyte circulation dynamics, and the development of techniques to differentiate between self-renewing tissue-resident, and monocyte-derived macrophages in different tissues, a new framework exists to contextualize and evaluate the significance and relevance of the monocyte/macrophage HIV reservoir. In this review, we discuss recent developments in monocyte and macrophage biology and appraise current and emerging techniques to quantify the reservoir. We discuss how this knowledge influences our evaluation of the myeloid HIV reservoir, the implications for HIV pathogenesis in both viremic and virologically-suppressed PLWH and the need to address the myeloid reservoir in future treatment and cure strategies.

Latent HIV reservoirs persist in people living with HIV despite effective antiretroviral therapy and contribute to rebound viremia upon treatment interruption. Macrophages are an important reservoir cell-type, but analysis of agents that modulate latency in macrophages is limited by lack of appropriate in vitro models. We therefore generated an experimental system to investigate this by purifying non-productively-infected human monocyte-derived macrophages (MDM) following in vitro infection with an M-tropic EGFP reporter HIV clone, and quantified activation of HIV transcription using live-cell fluorescence microscopy. The proportion of HIV-infected MDM was quantified by qPCR detection of HIV DNA, and GFP expression was validated as a marker of productive HIV infection by co-labelling of HIV Gag protein. HIV transcription spontaneously reactivated in latently-infected MDM at a rate of 0.22% ± 0.04 cells per day (mean ± SEM, n=10 independent donors), producing infectious virions able to infect heterologous T cells in coculture experiments, and both T cells and TZM-bl cells in a cell-free infection system using MDM culture supernatants. Polarization to an M1 phenotype with IFNγ + TNF resulted in a 2.3 fold decrease in initial HIV infection of MDM (p<0.001, n=8) and 1.4 fold decrease in spontaneous reactivation (p=0.025, n=6) whereas M2 polarization using IL-4 prior to infection led to a 1.6 fold decrease in HIV infectivity (p=0.028, n=8), but a 2.0 fold increase in the rate of HIV reactivation in latently-infected MDM (p=0.023, n=6). The latency reversing agents bryostatin and vorinostat, but not panobinostat, significantly induced HIV reactivation in latently infected MDM (p=0.031 and p=0.038, respectively, n=6). Importance: Agents which modulate latent HIV reservoirs in infected cells are of considerable interest to HIV cure strategies. The present study characterizes a robust, reproducible model enabling quantification of HIV reactivation in primary HIV-infected human MDM which is relatively insensitive to the monocyte donor source and hence suitable for evaluating latency modifiers in MDM. The rate of initial viral infection was greater than the rate of HIV reactivation, suggesting different mechanisms regulate these processes. HIV reactivation was sensitive to macrophage polarization, suggesting cellular and tissue environments influence HIV reactivation in different macrophage populations. Importantly, latently infected MDM showed different susceptibility to certain latency reversing agents known to be effective in T cells, indicating dedicated strategies may be required to target latently-infected macrophage populations in vivo .

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Objective: People living with HIV have an increased risk of cardiovascular disease (CVD) despite effective antiretroviral therapy (ART). Monocytes play a key role in the early stages of atherosclerosis-driven CVD by forming lipid-laden foam cells within artery walls. HIV infection potentiates foam cell formation ex vivo, but the mechanisms contributing to this are not known. Methods: We investigated the atherosclerosis-promoting potential of monocytes from 39 virologically suppressed men living with HIV (MLHIV) on ART and no evidence of CVD, and 25 HIV-uninfected controls of comparable age, sex, smoking status and CVD risk. Results: Despite absence of clinical atherosclerosis in both MLHIV and uninfected cohorts (evidenced by a carotid intima–media thickness of 0.6 mm for both groups; P = 0.254), monocytes from MLHIV showed increased potential to form atherosclerosis-promoting foam cells compared with controls in an ex-vivo assay (36.6% vs. 27.6%, respectively, P = 0.003). Consistent with observations of persistent inflammation and immune/endothelial activation in ART-treated HIV infection, levels of soluble tumour necrosis factor receptor II, CXCL10 and soluble VCAM-1 were elevated in MLHIV (P ≤ 0.005 for all), but were not significantly associated with foam cell formation. Foam cell formation was associated with an impaired ability of monocytes to undergo reverse transmigration, and a reduced ability to efflux cholesterol ex vivo (P < 0.05 for both). Importantly, foam cell formation declined significantly with duration of viral suppression (P = 0.004). Conclusion: These findings highlight the persistence of HIV-related changes to the atherogenic potential of monocytes despite long-term viral suppression, and provide insights into mechanisms potentially driving increased CVD in ART-treated HIV infection.

BackgroundHuman papillomavirus (HPV) is the causative agent in cervical cancer and HPV genotypes 16 and 18 cause the majority of these cancers. Natural killer (NK) cells destroy virally infected and tumour cells via killer immunoglobulin-like receptors (KIR) that recognize decreased MHC class I expression. These NK cells may contribute to clearance of HPV infected and/or dysplastic cells, however since KIR controls NK cell activity, KIR gene variation may determine outcome of infection.MethodsKIR gene frequencies were compared between 147 patients with a history of high-grade cervical intraepithelial neoplasia (CIN) and a control population of 187, to determine if any KIR genes are associated with high-grade CIN. In addition a comparison was also made between cases of high grade CIN derived from 30 patients infected with HPV 16/18 and 29 patients infected with non-16/18 HPV to determine if KIR variation contributes to the disproportional carcinogenesis derived from HPV 16/18 infection.ResultsHigh-grade CIN was weakly associated with the absence of KIR2DL2 and KIR2DS2 (p = 0.046 and 0.049 respectively, OR 0.6; 95% CI 0.4 – 0.9) but this association was lost after correction for multi-gene statistical analysis. No difference in KIR gene frequencies was found between high-grade CIN caused by HPV 16/18 and non-16/18.ConclusionNo strong association between KIR genes, high-grade CIN and HPV genotype was found in the Western Australian population.

Background Statins may help prevent cardiovascular disease (CVD) in people with human immunodeficiency virus (PWH) with chronic inflammation owing to their pleotropic lipid-lowering and anti-inflammatory properties. Methods The impact of 48 weeks of rosuvastatin therapy on inflammation and immune activation in a double-blind, placebo-controlled trial in PWH at moderate cardiovascular disease risk was assessed. Results Rosuvastatin did not alter plasma levels of interleukin 6, soluble tumor necrosis factor receptor type 2, CXCL10, soluble CD14, or soluble vascular cellular adhesion molecule 1 (P ≥ .1 for all). Proportions of CD16+ monocyte subsets were increased in PWH receiving rosuvastatin. Conclusions The potential benefits of statin use in PWH with normal lipid levels requires further clinical outcome research.

Infection with oncogenic human papillomavirus (HPV) genotypes is necessary for the development of cervical cancer. Testing for HPV DNA from liquid based cervical samples can be used as an adjunct to traditional cytological screening. In addition there are ongoing viral load, genotyping, and prevalence studies. Therefore, a sensitive DNA extraction method is needed to maximize the efficiency of HPV DNA detection. The XytXtract Tissue kit is a DNA extraction kit that is rapid and so could be useful for HPV testing, particularly in screening protocols. This study was undertaken to determine the suitability of this method for HPV detection. DNA extraction from HeLa and Caski cell lines containing HPV 18 and 16 respectively together with DNA from five liquid based cervical samples were used in a HPV PCR assay. DNA was also extracted using the QIAamp DNA mini kit (Qiagen, Hilden, Germany) as a comparison. DNA extracts were serially diluted and assayed. HPV DNA was successfully detected in cell lines and cervical samples using the XytXtract Tissue kit. In addition, the XytXtract method was found to be more sensitive than the QIAmp method as determined by a dilution series of the extracted DNA. While the XytXtract method is a closed, the QIAamp method uses a spin column with possible loss of DNA through DNA binding competition of the matrix, which could impact on the final extraction efficiency. The XytXtract is a cheap, rapid and efficient method for extracting HPV DNA from both cell lines and liquid based cervical samples.

Background: The physical decrements of aging predispose older adults to falls and fall-related injuries. Consequences of falling place financial and logistical burdens on the health care system. With an aging population, mitigation of risk and reduction of harm are important objectives. Studies show that exercise can improve balance and build muscle mass. The challenge is prescribing safe and evidence-based exercise regimens to older adults. Objectives: The objective of this evidence review was to determine if an exercise program can reduce fall rates and prolong functional independence among older adults living in the community. Data sources: This review included 14 randomized control trials and one quasi-experimental interventional study, all published between 2014 and 2020. Conclusions: The evidence suggests that a home- or community-based exercise program with formal instruction and health care provider involvement can be an effective fall-prevention and harm reduction strategy for community-dwelling older adults. Implications for practice: The evidence suggests that a home- or community-based exercise program may be an effective fall-prevention strategy for older adults living independently in the community. Health care providers should educate these patients about the benefits of exercise as a fall-prevention measure and assist patients in increasing participation in exercise programs by making referrals and promoting engagement in evidence-based exercise programs.