Markers of microbial translocation predict hypertension in HIV-infected individuals

Gut permeability is associated with lower insulin sensitivity in youth with perinatally acquired HIV

The relationships between alterations in the intestinal barrier, and bacterial translocation with the development of metabolic complications in youth with perinatally acquired HIV (YPHIV) have not been investigated. The PHACS Adolescent Master Protocol enrolled YPHIV across 15 U.S. sites, including Puerto Rico, from 2007 to 2009. For this analysis, we included YPHIV with HIV viral load 1000 c/ml or less, with at least one measurement of homeostatic assessment of insulin resistance (HOMA-IR) or nonhigh density lipoprotein (non-HDLc) between baseline and year 3 and plasma levels of intestinal fatty-acid binding protein (I-FABP), lipopolysaccharide-binding protein (LBP), and zonulin levels at baseline. We fit linear regression models using generalized estimating equations to assess the association of baseline log 10 gut markers with log 10 HOMA-IR and non-HDLc at all timepoints. HOMA-IR or non-HDLc was measured in 237, 189, and 170 PHIV at baseline, Yr2, and Yr3, respectively. At baseline, median age (Q1, Q3) was 12 years (10, 14), CD4 + cell count was 762 cells/μl (574, 984); 90% had HIV RNA less than 400 c/ml. For every 10-fold higher baseline I-FABP, HOMA-IR dropped 0.85-fold at baseline and Yr2. For a 10-fold higher baseline zonulin, there was a 1.35-fold increase in HOMA-IR at baseline, 1.23-fold increase in HOMA-IR at Yr2, and 1.20-fold increase in HOMA-IR at Yr3 in adjusted models. For a 10-fold higher baseline LBP, there was a 1.23-fold increase in HOMA-IR at baseline in the unadjusted model, but this was slightly attenuated in the adjusted model. Zonulin was associated with non-HDLc at baseline, but not for the other time points. Despite viral suppression, intestinal damage may influence downstream insulin sensitivity in YPHIV.

HIV-Associated Hypertension: Risks, Mechanisms, and Knowledge Gaps

HIV type 1 (HIV-1) is the causative agent of AIDS. Since the start of the epidemic, HIV/AIDS has been responsible for ≈40 million deaths. Additionally, an estimated 39 million people are currently infected with the virus. HIV-1 primarily infects immune cells, such as CD4+ (cluster of differentiation 4+) T lymphocytes (T cells), and as a consequence, the number of CD4+ T cells progressively declines in people living with HIV. Within a span of ≈10 years, HIV-1 infection leads to the systemic failure of the immune system and progression to AIDS. Fortunately, potent antiviral therapy effectively controls HIV-1 infection and prevents AIDS-related deaths. The efficacy of the current antiviral therapy regimens has transformed the outcome of HIV/AIDS from a death sentence to a chronic disease with a prolonged lifespan of people living with HIV. However, antiviral therapy is not curative, is challenged by virus resistance, can be toxic, and, most importantly, requires lifelong adherence. Furthermore, the improved lifespan has resulted in an increased incidence of non-AIDS-related morbidities in people living with HIV including cardiovascular diseases, renal disease, liver disease, bone disease, cancer, and neurological conditions. In this review, we summarize the current state of knowledge of the cardiovascular comorbidities associated with HIV-1 infection, with a particular focus on hypertension. We also discuss the potential mechanisms known to drive HIV-1-associated hypertension and the knowledge gaps in our understanding of this comorbid condition. Finally, we suggest several directions of future research to better understand the factors, pathways, and mechanisms underlying HIV-1-associated hypertension in the post-antiviral therapy era.

Placental TLR recognition of salivary and subgingival microbiota is associated with pregnancy complications

BACKGROUND

Pre-term birth, the leading cause of neonatal mortality, has been associated with maternal periodontal disease and the presence of oral pathogens in the placenta. However, the mechanisms that underpin this link are not known. This investigation aimed to identify the origins of placental microbiota and to interrogate the association between parturition complications and immune recognition of placental microbial motifs. Video Abstract METHODS: Saliva, plaque, serum, and placenta were collected during 130 full-term (FT), pre-term (PT), or pre-term complicated by pre-eclampsia (PTPE) deliveries and subjected to whole-genome shotgun sequencing. Real-time quantitative PCR was used to measure toll-like receptors (TLR) 1-10 expression in placental samples. Source tracking was employed to trace the origins of the placental microbiota.

RESULTS

We discovered 10,007 functionally annotated genes representing 420 taxa in the placenta that could not be attributed to contamination. Placental microbial composition was the biggest discriminator of pregnancy complications, outweighing hypertension, BMI, smoking, and maternal age. A machine-learning algorithm trained on this microbial dataset predicted PTPE and PT with error rates of 4.05% and 8.6% (taxonomy) and 6.21% and 7.38% (function). Logistic regression revealed 32% higher odds of parturition complication (95% CI 2.8%, 81%) for every IQR increase in the Shannon diversity index after adjusting for maternal smoking status, maternal age, and gravida. We also discovered distinct expression patterns of TLRs that detect RNA- and DNA-containing antigens in the three groups, with significant upregulation of TLR9, and concomitant downregulation of TLR7 in PTPE and PT groups, and dense correlation networks between microbial genes and these TLRs. 70-82% of placental microbiota were traced to serum and thence to the salivary and subgingival microbiomes. The oral and serum microbiomes of PTPE and PT groups displayed significant enrichment of genes encoding iron transport, exosome, adhesion, quorum sensing, lipopolysaccharide, biofilm, and steroid degradation.

CONCLUSIONS

Within the limits of cross-sectional analysis, we find evidence to suggest that oral bacteria might translocate to the placenta via serum and trigger immune signaling pathways capable of inducing placental vascular pathology. This might explain, in part, the higher incidence of obstetric syndromes in women with periodontal disease.

Mechanisms underlying HIV-associated cognitive impairment and emerging therapies for its management

People living with HIV are affected by the chronic consequences of neurocognitive impairment (NCI) despite antiretroviral therapies that suppress viral replication, improve health and extend life. Furthermore, viral suppression does not eliminate the virus, and remaining infected cells may continue to produce viral proteins that trigger neurodegeneration. Comorbidities such as diabetes mellitus are likely to contribute substantially to CNS injury in people living with HIV, and some components of antiretroviral therapy exert undesirable side effects on the nervous system. No treatment for HIV-associated NCI has been approved by the European Medicines Agency or the US Food and Drug Administration. Historically, roadblocks to developing effective treatments have included a limited understanding of the pathophysiology of HIV-associated NCI and heterogeneity in its clinical manifestations. This heterogeneity might reflect multiple underlying causes that differ among individuals, rather than a single unifying neuropathogenesis. Despite these complexities, accelerating discoveries in HIV neuropathogenesis are yielding potentially druggable targets, including excessive immune activation, metabolic alterations culminating in mitochondrial dysfunction, dysregulation of metal ion homeostasis and lysosomal function, and microbiome alterations. In addition to drug treatments, we also highlight the importance of non-pharmacological interventions. By revisiting mechanisms implicated in NCI and potential interventions addressing these mechanisms, we hope to supply reasons for optimism in people living with HIV affected by NCI and their care providers.

Effect of immunological non-response on incidence of Non-AIDS events in people living with HIV: A retrospective multicenter cohort study in Taiwan

BACKGROUND

People living with HIV (PLWH) are susceptible to non-AIDS-related events, particularly those with immunological nonresponses (INRs) to highly active antiretroviral therapy (HAART). This study assessed the association of INRs with incident non-AIDS-related events among PLWH.

METHODS

This multicenter retrospective cohort study enrolled PLWH who had newly diagnosed stage 3 HIV and received HAART between January 1, 2008, and December 31, 2019. The patients were divided into two groups according to their immunological responses on the 360th day after HAART initiation: INR and non-INR groups. Cox regression and sensitivity analyses were conducted to estimate the effects of INRs on overall and individual categories of non-AIDS-related events (malignancies, vascular diseases, metabolic disorders, renal diseases, and psychiatric disorders). Patient observation started on the 360th day after HAART initiation and continued until February 28, 2022, death, or an outcome of interest, whichever occurred first.

RESULTS

Among the 289 included patients, 44 had INRs. Most of the included patients were aged 26-45 years (69.55%) and were men who have sex with men (89.97%). Many patients received HIV diagnoses between 2009 and 2012 (38.54%). INRs (vs. non-INRs) were associated with composite non-AIDS-related events (adjusted hazard ratio [aHR] = 1.80; 95% confidence interval [CI]: 1.19-2.73) and metabolic disorders (aHR = 1.75; 95% CI: 1.14-2.68). Sensitivity analyses revealed consistent results for each Cox regression model for both composite non-AIDS-related events and metabolic diseases.

CONCLUSION

Clinicians should be vigilant and implement early intervention and rigorous monitoring for non-AIDS-related events in PLWH with INRs to HAART.

HIV and hypertension epidemiology

PURPOSE OF REVIEW

The aim of this study was to provide an overview of the burden, pathogenesis, and recent recommendations for treating hypertension among people living with HIV (PLWH). This review is relevant because of the increase in the prevalence of HIV as a chronic disease and the intersection of the increasing prevalence of hypertension.

RECENT FINDINGS

The contribution of HIV to the pathogenesis of hypertension is complex and still incompletely understood. Evidence suggests that chronic inflammation from HIV, antiretroviral treatment (ART), and comorbidities such as renal disease and insulin resistance contribute to developing hypertension in PLWH. Treatment is not distinct from guidelines for HIV-noninfected people. Nonpharmacological guidelines such as decreasing blood pressure by promoting a healthy lifestyle emphasizing exercise, weight loss, and smoking cessation are still recommended in the literature. The pharmacological management of hypertension in PLWH is similar, but special attention must be given to specific drugs with potential interaction with ART regimens. Further research is needed to investigate the pathways and effects of hypertension on HIV.

SUMMARY

There are different pathways to the pathogenesis of hypertension in PLWH. Clinicians should take it into consideration to provide more precise management of hypertension in PLWH. Further research into the subject is still required.

Symptoms and Comorbidities Differ Based on Race and Weight Status in Persons with HIV in the Northern United States: a Cross-Sectional Study

BACKGROUND

Persons with HIV (PWHIV) on highly active antiretroviral treatments (HAART) may require specialized care based on health and demographic indicators. This study investigated the association of comorbidities, race, weight status, and gastrointestinal (GI) and cardiovascular (CV) symptoms among PWHIV.

METHODS

The Symptom Checklist, Co-Morbidity Questionnaire, and Sociodemographic Questionnaire were used to assess weight status and GI and CV symptoms among 283 PWHIV. Data were analyzed using latent class analysis on John's Macintosh Project 13 Platform.

RESULTS

Participants were majority Black (50%), 69% male, and 35% AIDS diagnosed. Ages were 25 to 66. Clusters included least symptomatic status, weight gain, and weight loss by Black and non-Black participants. The non-Black weight gain cluster reported a higher incidence of AIDS (70.6% vs 38.2%), nausea (70.6% vs 17.6%), diarrhea (70.6% vs 26.5%), and shortness of breath (58.8% vs 20.6%) compared to the Black weight gain cluster. The Black weight loss cluster reported a higher incidence of CV symptoms such as chest palpitations (42.2% vs 2.7%), chest pain (44.4% vs 8.1%), and shortness of breath (73.3% vs 35.1%). Moreover, the Black weight loss cluster reported a higher incidence of all GI symptoms with the most prominent being diarrhea (71.1% vs 48.6%) compared to the non-Black weight loss cluster.

CONCLUSIONS

The existing racial disparities in health-related quality of life for PWHIV may be improved through precision health and nutrition modifications. Continued research is needed investigating differential health outcomes among PWHIV on HAART.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00222716. Registered 22 September 2005. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT00222716?term=NCT00222716&draw=2&rank=1.

Cardiovascular Disease and Thrombosis in HIV Infection

HIV infection has transitioned from an acute, fatal disease to a chronic one managed by antiretroviral therapy. Thus, the aging population of people living with HIV (PLWH) continues to expand. HIV infection results in a dysregulated immune system, wherein CD4+ T cells are depleted, particularly in the gastrointestinal tract, disrupting the gut epithelial barrier. Long-term HIV infection is associated with chronic inflammation through potentially direct mechanisms caused by viral replication or exposure to viral proteins and indirect mechanisms resulting from increased translocation of microbial products from the intestine or exposure to antiretroviral therapy. Chronic inflammation (as marked by IL [interleukin]-6 and CRP [C-reactive protein]) in PLWH promotes endothelial cell dysfunction and atherosclerosis. PLWH show significantly increased rates of cardiovascular disease, such as myocardial infarction (risk ratio, 1.79 [95% CI, 1.54-2.08]) and stroke (risk ratio, 2.56 [95% CI, 1.43-4.61]). In addition, PLWH have increased levels of the coagulation biomarker D-dimer and have a two to ten-fold increased risk of venous thromboembolism compared with the general population. Several small clinical trials analyzed the effect of different antithrombotic agents on platelet activation, coagulation, inflammation, and immune cell activation. Although some markers for coagulation were reduced, most agents failed to reduce inflammatory markers in PLWH. More studies are needed to understand the underlying mechanisms driving inflammation in PLWH to create better therapies for lowering chronic inflammation in PLWH. Such therapies can potentially reduce atherosclerosis, cardiovascular disease, and thrombosis rates in PLWH and thus overall mortality in this population.

The Gut Microbiome, Microbial Metabolites, and Cardiovascular Disease in People Living with HIV

PURPOSE OF REVIEW

To synthesize recent evidence relating the gut microbiome and microbial metabolites to cardiovascular disease (CVD) in people living with HIV (PLWH).

RECENT FINDINGS

A few cross-sectional studies have reported on the gut microbiome and cardiovascular outcomes in the context of HIV, with no consistent patterns emerging. The largest such study found that gut Fusobacterium was associated with carotid artery plaque. More studies have evaluated microbial metabolite trimethylamine N-oxide with CVD risk in PLWH, but results were inconsistent, with recent prospective analyses showing null effects. Studies of other microbial metabolites are scarce. Microbial translocation biomarkers (e.g., lipopolysaccharide binding protein) have been related to incident CVD in PLWH. Microbial translocation may increase CVD risk in PLWH, but there is insufficient and/or inconsistent evidence regarding specific microbial species and microbial metabolites associated with cardiovascular outcomes in PLWH. Further research is needed in large prospective studies integrating the gut microbiome, microbial translocation, and microbial metabolites with cardiovascular outcomes in PLWH.

Relevance of biomarkers indicating gut damage and microbial translocation in people living with HIV

The intestinal barrier has the daunting task of allowing nutrient absorption while limiting the entry of microbial products into the systemic circulation. HIV infection disrupts the intestinal barrier and increases intestinal permeability, leading to microbial product translocation. Convergent evidence has shown that gut damage and an enhanced level of microbial translocation contribute to the enhanced immune activation, the risk of non-AIDS comorbidity, and mortality in people living with HIV (PLWH). Gut biopsy procedures are invasive, and are not appropriate or feasible in large populations, even though they are the gold standard for intestinal barrier investigation. Thus, validated biomarkers that measure the degree of intestinal barrier damage and microbial translocation are needed in PLWH. Hematological biomarkers represent an objective indication of specific medical conditions and/or their severity, and should be able to be measured accurately and reproducibly via easily available and standardized blood tests. Several plasma biomarkers of intestinal damage, i.e., intestinal fatty acid-binding protein (I-FABP), zonulin, and regenerating islet-derived protein-3α (REG3α), and biomarkers of microbial translocation, such as lipopolysaccharide (LPS) and (1,3)-β-D-Glucan (BDG) have been used as markers of risk for developing non-AIDS comorbidities in cross sectional analyses and clinical trials, including those aiming at repair of gut damage. In this review, we critically discuss the value of different biomarkers for the estimation of gut permeability levels, paving the way towards developing validated diagnostic and therapeutic strategies to repair gut epithelial damage and to improve overall disease outcomes in PLWH.

Risk Factors for Incident Hypertension Within 1 Year of Initiating Antiretroviral Therapy Among People with HIV

Hypertension (HTN) is a common comorbidity among people with HIV and associated with an increased risk for atherosclerotic cardiovascular disease and chronic kidney disease. The relationship of antiretroviral therapy (ART) initiation to incident HTN remains a clinical question. We determined HTN incidence at 48 weeks of follow-up among ART-naive participants without HTN and not taking antihypertensive medications at ART initiation through randomized clinical trials through the AIDS Clinical Trial Group between 1999 and 2011. We assessed the association of baseline characteristics, including randomized ART agents with HTN incidence at 48 weeks using Poisson regression models. Incident HTN was defined as blood pressure ≥130/80 mmHg, or use of antihypertensive medication. Among 2,614 participants, mean age was 37 ± 10 years, 79% male sex, and 36% African American race. After 48 weeks, 839 participants (32%) developed HTN. Receiving a non-nucleoside reverse transcriptase inhibitor (NNRTI) was associated with an increased relative risk (RR) of incident HTN, while the risk was lower for protease inhibitor use. Stavudine and efavirenz were associated with an increased RR of developing HTN, while tenofovir disoproxil fumarate, darunavir/ritonavir, and atazanavir/ritonavir were associated with a decreased risk of developing HTN. Additionally, older age, higher body mass index (BMI), and having hepatitis C were associated with an increased risk for developing HTN, while women and participants with a higher baseline CD4 count were at a decreased risk of developing HTN at 48 weeks. One third of these ART naive participants developed HTN after ART initiation. NNRTIs, notably efavirenz, and stavudine were associated with an increased risk of HTN. Additional factors associated with HTN included traditional factors like older age and higher BMI, and advanced HIV disease (lower CD4 count). (Clinicaltrials.gov: NCT00001137).

Hypertension and human immunodeficiency virus: A paradigm for epithelial sodium channels?

Hypertension is a risk factor for end organ damage and death and is more common in persons with HIV compared to the general population. Several mechanisms have been studied in the pathogenesis of hypertension. Current evidence suggests that the epithelial sodium channel (ENaC) plays a key role in regulating blood pressure through the transport of sodium and water across membranes in the kidney tubules, resulting in retention of sodium and water and an altered fluid balance. However, there is scarcity of information that elucidates the role of ENaC in HIV as it relates to increasing the risk for development or pathogenesis of hypertension. This review summarized the evidence to date implicating a potential role for altered ENaC activity in contributing to hypertension in patients with HIV.

Soluble Biomarkers of Cognition and Depression in Adults with HIV Infection in the Combination Therapy Era

PURPOSE OF REVIEW

Cognitive impairment and depression continue to be common among people with HIV (PWH) in the combination antiretroviral therapy (ART) era. A better understanding of the biological mechanisms that may underpin these disorders is needed. The purpose of this review is to describe published findings on soluble biomarkers from blood and cerebrospinal fluid (CSF) that have been associated with either cognition or depression among PWH in the setting of ART.

RECENT FINDINGS

Several biomarkers, including those that reflect viral persistence, monocyte/macrophage activation, and other processes, are associated with cognition and depressive symptoms. Some but not all results have been consistent across multiple studies. More research has been published on biomarkers of cognition relative to biomarkers of depression (particularly from CSF). More studies are needed that investigate multiple biomarkers to understand the role of distinct but additive pathways in these disorders and to guide the development of new therapies.

Validation of Two Kinetic Assays for the Quantification of Endotoxin in Human Serum

Background: There is an emerging evidence of the role of the microbiome in neurological diseases. Endotoxin is a component of gram-negative bacteria and thought to be one of the possible signals between the gut microbiota and the immune system. Previous studies explored the blood levels of endotoxin using an endpoint chromogenic assay. Methods: We validated and compared the analytical performance of two kinetic assays for the quantification of endotoxin in serum: (1) the Limulus Amebocyte Lysate (LAL) Kinetic-QCL assay and (2) the turbidimetric LAL Pyrogent-5000 assay. We used the best-performing validated assay to measure the endotoxin level in 20 patients with multiple sclerosis (MS) and eight healthy controls. Results: The Pyrogent-5000 and QCL assay achieved similar performance in regard to spike recovery and linear dilution; however, the Pyrogent-5000 had a better signal to noise in the calibrator curve. By using the Pyrogent-5000 assay, we found that serum samples from MS patients and healthy controls have a similar level of endotoxin; hence, we did not find evidence to support a penetration of endotoxin in the blood of MS patients. Our findings do not exclude a role of endotoxin in mediating signals from the gut microbiota in MS patients directly at the gut-blood barrier where numerous antigen-presenting cells are actively sensing metabolites and bacterial products.

Altered Intestinal Permeability and Fungal Translocation in Ugandan Children With Human Immunodeficiency Virus

BACKGROUND

Children with perinatally acquired human immunodeficiency virus (HIV; PHIVs) face a lifelong cumulative exposure to HIV and antiretroviral therapy (ART). The relationship between gut integrity, microbial translocation, and inflammation in PHIV is poorly understood.

METHODS

This is a cross-sectional study in 57 PHIVs, 59 HIV-exposed but uninfected children, and 56 HIV-unexposed and -uninfected children aged 2-10 years old in Uganda. PHIVs were on stable ART with HIV-1 RNA <400 copies/mL. We measured markers of systemic inflammation, monocyte activation, and gut integrity. Kruskal-Wallis tests were used to compare markers by group and the Spearman correlation was used to assess correlations between biomarkers.

RESULTS

The mean age of all participants was 7 years and 55% were girls. Among PHIVs, the mean CD4 % was 34%, 93% had a viral load ≤20 copies/mL, and 79% were on a nonnucleoside reverse transcriptase inhibitor regimen. Soluble cluster of differentiation 14 (sCD14), beta-D-glucan (BDG), and zonulin were higher in the PHIV group (P ≤ .01). Intestinal fatty acid binding protein (I-FABP) and lipopolysaccharide binding protein (LBP) did not differ between groups (P > .05). Among PHIVs who were breastfed, levels of sCD163 and interleukin 6 (IL6) were higher than levels in PHIV who were not breastfed (P < .05). Additionally, in PHIVs with a history of breastfeeding, sCD14, BDG, LBP, zonulin, and I-FABP correlated with several markers of systemic inflammation, including high-sensitivity C-reactive protein, IL6, d-dimer, and systemic tumor necrosis factor receptors I and II (P ≤ .05).

CONCLUSIONS

Despite viral suppression, PHIVs have evidence of altered gut permeability and fungal translocation. Intestinal damage and the resultant bacterial and fungal translocations in PHIVs may play a role in the persistent inflammation that leads to many end-organ diseases in adults.Despite viral suppression, children with perinatally acquired human immunodeficiency virus (HIV) in Uganda have evidence of alterations in intestinal permeability and fungal translocation, compared to HIV-exposed but uninfected and HIV-unexposed children, which may play a role in HIV-associated chronic inflammation.

Sexual Dimorphic Role of CD14 (Cluster of Differentiation 14) in Salt-Sensitive Hypertension and Renal Injury

Genomic sequence and gene expression association studies in animals and humans have identified genes that may be integral in the pathogenesis of various diseases. CD14 (cluster of differentiation 14)-a cell surface protein involved in innate immune system activation-is one such gene associated with cardiovascular and hypertensive disease. We previously showed that this gene is upregulated in renal macrophages of Dahl salt-sensitive animals fed a high-salt diet; here we test the hypothesis that CD14 contributes to the elevated pressure and renal injury observed in salt-sensitive hypertension. Using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9), we created a targeted mutation in the CD14 gene on the Dahl SS (SS/JrHSDMcwi) background and validated the absence of CD14 peptides via mass spectrometry. Radiotelemetry was used to monitor blood pressure in wild-type and CD14^-/- animals challenged with high salt and identified infiltrating renal immune cells via flow cytometry. Germline knockout of CD14 exacerbated salt-sensitive hypertension and renal injury in female animals but not males. CD14^-/- females demonstrated increased infiltrating macrophages but no difference in infiltrating lymphocytes. Transplant of CD14^+/+ or CD14^-/- bone marrow was used to isolate the effects of CD14 knockout to hematopoietic cells and confirmed that the differential phenotype observed was due to knockout of CD14 in hematopoietic cells. Ovariectomy was used to remove the influence of female sex hormones, which completely abrogated the effect of CD14 knockout. These studies provide a novel treatment target and evidence of a new dichotomy in immune activation between sexes within the context of hypertensive disease where CD14 regulates immune cell activation and renal injury.

Incidence of hypertension among persons living with HIV in China: a multicenter cohort study

BACKGROUND

Life expectancy among persons living with HIV (PLWH) has improved with increasing access to antiretroviral therapy (ART), however incidence of chronic comorbidities has simultaneously increased. No data are available regarding the incidence of hypertension among Chinese PLWH.

METHODS

We analyzed data collected from patients enrolled in two prospective longitudinal multicenter studies of PLWH initiating ART in China. Incidence rate of hypertension per 100 person-years (PYs) among PLWH was calculated, and Cox proportional hazards models was used to evaluate the association between incident hypertension and traditional and HIV-associated risk factors.

RESULTS

Of 1078 patients included in this analysis, 984 ART-naïve patients were hypertension-free at baseline, and contributed 2337.7 PYs of follow up, with a median follow-up period of 1.8 years (range: 1.2-3.2) after initiation of ART. Incidence of hypertension was 7.6 [95% confidence interval (CI): 6.5-8.7] per 100 PYs. In the Cox regression analysis, incidence of hypertension was positively associated with body mass index [adjusted hazard ratio (aHR) 1.07 (1.01,1.13), p = 0.02] and recent viral load (aHR 1.28, 95% CI:1.08-1.51, p < 0.01), and negatively associated with recent CD4+/CD8+ ratio (aHR 0.14, 95% CI:0.06-0.31, p < 0.001), zidovudine exposure (aHR 0.15, 95% CI: 0.10-0.24, p < 0.001) and tenofovir disoproxil fumarate exposure (aHR 0.13, 95% CI: 0.08-0.21, p < 0.001).

CONCLUSIONS

The incidence of hypertension was relatively high among Chinese PLWH initiating ART. Recent low CD4+/CD8+ ratio and detectable HIV viremia were associated with incident hypertension, whereas receipt of ART was associated with reduced risk. Hypertension may be mitigated, in part, by excellent HIV care, including viral suppression with ART.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00872417 registered on 31 March, 2009, and NCT01844297 registered on 1 May, 2013.

HIV, Sexual Orientation, and Gut Microbiome Interactions

Recent studies have raised interest in the possibility that dysbiosis of the gut microbiome (i.e., the communities of bacteria residing in the intestine) in HIV-infected patients could contribute to chronic immune activation, and, thus, to elevated mortality and increased risk of inflammation-related clinical diseases (e.g., stroke, cardiovascular disease, cancer, long-bone fractures, and renal dysfunction) found even in those on effective antiretroviral therapy. Yet, to date, a consistent pattern of HIV-associated dysbiosis has not been identified. What is becoming clear, however, is that status as a man who has sex with men (MSM) may profoundly impact the structure of the gut microbiota, and that this factor likely confounded many HIV-related intestinal microbiome studies. However, what factor associated with MSM status drives these gut microbiota-related changes is unclear, and what impact, if any, these changes may have on the health of MSM is unknown. In this review, we outline available data on changes in the structure of the gut microbiome in HIV, based on studies that controlled for MSM status. We then examine what is known regarding the gut microbiota in MSM, and consider possible implications for research and the health of this population. Lastly, we discuss knowledge gaps and needed future studies.

The Impact of Human Immunodeficiency Virus Infection on Gut Microbiota α-Diversity: An Individual-level Meta-analysis

BACKGROUND

Whether human immunodeficiency virus (HIV) infection impacts gut microbial α-diversity is controversial. We reanalyzed raw 16S ribosomal RNA (rRNA) gene sequences and metadata from published studies to examine α-diversity measures between HIV-uninfected (HIV-) and HIV-infected (HIV+) individuals.

METHODS

We conducted a systematic review and individual level meta-analysis by searching Embase, Medline, and Scopus for original research studies (inception to 31 December 2017). Included studies reported 16S rRNA gene sequences of fecal samples from HIV+ patients. Raw sequence reads and metadata were obtained from public databases or from study authors. Raw reads were processed through standardized pipelines with use of a high-resolution taxonomic classifier. The χ2 test, paired t tests, and generalized linear mixed models were used to relate α-diversity measures and clinical metadata.

RESULTS

Twenty-two studies were identified with 17 datasets available for analysis, yielding 1032 samples (311 HIV-, 721 HIV+). HIV status was associated with a decrease in measures of α-diversity (P < .001). However, in stratified analysis, HIV status was associated with decreased α-diversity only in women and in men who have sex with women (MSW) but not in men who have sex with men (MSM). In analyses limited to women and MSW, controlling for HIV status, women displayed increased α-diversity compared with MSW.

CONCLUSIONS

Our study suggests that HIV status, sexual risk category, and gender impact gut microbial community α-diversity. Future studies should consider MSM status in gut microbiome analyses.

Demographics and health profile on precursors of non-communicable diseases in adults testing for HIV in Soweto, South Africa: a cross-sectional study

OBJECTIVES

This cross-sectional study investigated the burden of HIV-non-communicable disease (NCD) precursor comorbidity by age and sex. Policies stress integrated HIV-NCD screenings; however, NCD screening is poorly implemented in South African HIV testing services (HTS).

SETTING

Walk-in HTS Centre in Soweto, South Africa.

PARTICIPANTS

325 voluntary adults, aged 18+ years, who provided written or verbal informed consent (with impartial witness) for screening procedures were enrolled.

PRIMARY AND SECONDARY OUTCOMES

Data on sociodemographics, tuberculosis and sexually transmitted infection symptoms, blood pressure (BP) (≥140/90=elevated) and body mass index (<18.5 underweight; 18.5-25.0 normal; >25 overweight/obese) were stratified by age-group, sex and HIV status.

RESULTS

Of the 325 participants, the largest proportions were female (51.1%; n=166/325), single (71.5%; n=231/323) and 25-34 years (33.8%; n=110/325). Overall, 20.9% (n=68/325) were HIV infected, 27.5% (n=89/324) had high BP and 33.5% (n=109/325) were overweight/obese. Among HIV-infected participants, 20.6% (14/68) had high BP and 30.9% (21/68) were overweight/obese, as compared with 29.3% (75/256) and 12.1% (31/256) of the HIV-uninfected participants, respectively. Females were more likely HIV-infected compared with males (26.5% (44/166) vs 15.1% (24/159); p=0.012). In both HIV-infected and uninfected groups, high BP was most prevalent in those aged 35-44 years (25% (6/24) vs 36% (25/70); p=0.3353) and >44 years (29% (4/14) vs 48% (26/54); p=0.1886). Males had higher BP than females (32.9% (52/158) vs 22.3% (37/166); p=0.0323); more females were overweight/obese relative to males (45.8% (76/166) vs 20.8% (33/159); p<0.0001). Females were more likely to be HIV infected and overweight/obese.

CONCLUSION

Among HTS clients, NCD precursors rates and co-morbidities were high. Elevated BP occurred more in older participants. Targeted integrated interventions for HIV-infected females and HIV-infected people aged 18-24 and 35-44 years could improve HIV public health outcomes. Additional studies on whether integrated HTS will improve the uptake of NCD treatment and improve health outcomes are required.

Microbial Translocation Is Linked to a Specific Immune Activation Profile in HIV-1-Infected Adults With Suppressed Viremia

Persistent immune activation in virologically suppressed HIV-1 patients, which may be the consequence of various factors including microbial translocation, is a major cause of comorbidities. We have previously shown that different profiles of immune activation may be distinguished in virological responders. Here, we tested the hypothesis that a particular profile might be the consequence of microbial translocation. To this aim, we measured 64 soluble and cell surface markers of inflammation and CD4+ and CD8+ T-cell, B cell, monocyte, NK cell, and endothelial activation in 140 adults under efficient antiretroviral therapy, and classified patients and markers using a double hierarchical clustering analysis. We also measured the plasma levels of the microbial translocation markers bacterial DNA, lipopolysaccharide binding protein (LBP), intestinal-fatty acid binding protein, and soluble CD14. We identified five different immune activation profiles. Patients with an immune activation profile characterized by a high percentage of CD38+CD8+ T-cells and a high level of the endothelial activation marker soluble Thrombomodulin, presented with higher LBP mean (± SEM) concentrations (33.3 ± 1.7 vs. 28.7 ± 0.9 μg/mL, p = 0.025) than patients with other profiles. Our data are consistent with the hypothesis that the immune activation profiles we described are the result of different etiological factors. We propose a model, where particular causes of immune activation, as microbial translocation, drive particular immune activation profiles responsible for particular comorbidities.

Blood pressure trajectories and the mediated effects of body mass index and HIV-related inflammation in a mixed cohort of people with and without HIV in rural Uganda

We sought to describe changes in blood pressure and estimate the effect of HIV on blood pressure (BP) over 4 years of observation in a cohort of 155 HIV-infected adults (≥40 years) on antiretroviral therapy (ART) and 154 sex- and age-quartile-matched, population-based, HIV-uninfected controls for four years in rural Uganda, we compared changes in blood pressure (BP) by HIV serostatus and tested whether body mass index and inflammation (high-sensitivity C-reactive protein and interleukin-6) and immune activation (sCD14 and sCD163) mediated the effects of HIV on BP using hierarchical multivariate and two-stage parametric regression models. Overall HIV-uninfected participants had higher mean BP than HIV-infected counterparts (differences in trend P < 0.0001 for diastolic BP and P = 0.164 for systolic BP). After initial declines in BP in both groups between years 1 and 2, BP moderately increased in both groups through year 4, with greater change over time observed in the HIV-uninfected group. Body mass index mediated 72% (95%CI 57, 97) of the association between HIV and systolic BP. We found a minimal mediating effect of sCD14 on the relationship between HIV and SBP (9%, 95% CI 5%, 21%), but found no association between other HIV-related biomarkers. Over four years of observation, HIV-infected people in rural Uganda have lower BP than HIV-uninfected counterparts despite having higher levels of inflammation. BMI, rather than measures of HIV-associated inflammation, explained a majority of the difference in BP observed.

Blood Pressure, HIV, and Cocaine Use Among Ethnically and Racially Diverse Individuals

OBJECTIVES

Racial minorities are at greater risk of cardiovascular disease (CVD), and CVD is the primary cause of mortality among human immunodeficiency virus (HIV)-infected individuals. Cocaine use also has been associated with hypertension. This study examined the contribution of lifestyle factors to systolic, diastolic, and mean arterial pressure (MAP) among people living with HIV and cocaine users from racially and ethnically diverse backgrounds.

METHODS

Participants (N = 401: 213 men, 188 women) aged 18 to 50 years with no history of CVD were recruited from South Florida. A total of 200 participants were HIV-cocaine-infected, 100 were HIV-infected individuals with no history of cocaine use, and 101 were HIV-uninfected individuals with cocaine abuse or dependence. Carotid intima-media thickness and plaque, blood pressure (BP), and lifestyle risk were assessed.

RESULTS

Mean age was 36 years (standard deviation 9.33); the majority (62%) were African American. Carotid plaques were identified in 23% of participants; 42% were obese, 68% engaged in ≥150 minutes of weekly exercise, and 68% were smokers. Sex, body mass index (BMI), and diet were associated with systolic BP. Age, BMI, cannabis use, and diet were associated with diastolic BP and MAP.

CONCLUSIONS

Age, BMI, cannabis use, and diet were associated with increased diastolic BP and MAP. Cocaine did not emerge as a significant predictor of CVD after controlling for cannabis dependence. Cocaine and HIV lacked significant association with CVD, possibly because the majority of the sample was younger than age 40. Lifestyle modifications and substance abuse counseling may be important in preventing CVD among those without a history of CVD.

Effects of HIV viremia on the gastrointestinal microbiome of young MSM

OBJECTIVE

We employed a high-dimensional covariate adjustment method in microbiome analysis to better control for behavioural and clinical confounders, and in doing so examine the effects of HIV on the rectal microbiome.

DESIGN

Three hundred and eighty-three MSM were grouped into four HIV viremia categories: HIV negative (n = 200), HIV-positive undetectable (HIV RNA < 20 copies/ml; n = 66), HIV-positive suppressed (RNA 20-200 copies/ml; n = 72) and HIV-positive viremic (RNA > 200 copies/ml; n = 45).

METHODS

We performed 16S rRNA gene sequencing on rectal swab samples and used inverse probability of treatment-weighted marginal structural models to examine differences in microbial composition by HIV viremia category.

RESULTS

HIV viremia explained a significant amount of variability in microbial composition in both unadjusted and covariate-adjusted analyses (R = 0.011, P = 0.02). Alterations in bacterial taxa were more apparent with increasing viremia. Relative to the HIV-negative group, HIV-positive undetectable participants showed depletions in Brachyspira, Campylobacter and Parasutterella, while suppressed participants demonstrated depletions in Barnesiella, Brachyspira and Helicobacter. The microbial signature of viremic men was most distinct, showing enrichment in inflammatory genera Peptoniphilus, Porphyromonas and Prevotella and depletion of Bacteroides, Brachyspira and Faecalibacterium, among others.

CONCLUSION

Our study shows that, after accounting for the influence of multiple confounding factors, HIV is associated with dysbiosis in the gastrointestinal microbiome in a dose-dependent manner. This analytic approach may allow for better identification of true microbial associations by limiting the effects of confounding, and thus improve comparability across future studies.

Association between exposure to antiretroviral drugs and the incidence of hypertension in HIV-positive persons: the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study

OBJECTIVES

Previous studies have suggested that hypertension in HIV-positive individuals is associated primarily with traditional risk factors such as older age, diabetes and dyslipidaemia. However, controversy remains as to whether exposure to antiretroviral (ARV) drugs poses additional risk, and we investigated this question in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) cohort.

METHODS

The incidence of hypertension [systolic blood pressure (BP) > 140 and/or diastolic BP > 90 mmHg and/or initiation of antihypertensive treatment] was determined overall and in strata defined by demographic, metabolic and HIV-related factors, including cumulative exposure to each individual ARV drug. Predictors of hypertension were identified using uni- and multivariable Poisson regression models.

RESULTS

Of 33 278 included persons, 7636 (22.9%) developed hypertension over 223 149 person-years (PY) [incidence rate: 3.42 (95% confidence interval (CI) 3.35-3.50) per 100 PY]. In univariable analyses, cumulative exposure to most ARV drugs was associated with an increased risk of hypertension. After adjustment for demographic, metabolic and HIV-related factors, only associations for nevirapine [rate ratio 1.07 (95% CI: 1.04-1.13) per 5 years] and indinavir/ritonavir [rate ratio 1.12 (95% CI: 1.04-1.20) per 5 years] remained statistically significant, although effects were small. The strongest independent predictors of hypertension were male gender, older age, black African ethnicity, diabetes, dyslipidaemia, use of lipid-lowering drugs, high body mass index (BMI), renal impairment and a low CD4 count.

CONCLUSIONS

We did not find evidence for any strong independent association between exposure to any of the individual ARV drugs and the risk of hypertension. Findings provide reassurance that screening policies and preventative measures for hypertension in HIV-positive persons should follow algorithms used for the general population.

Hypertension in people living with HIV

PURPOSE OF REVIEW

This review describes what is known concerning the burden of hypertension among people living with HIV (PLHIV), and also addresses relevant topics with respect to its risk factors and clinical management.

RECENT FINDINGS

Hypertension is highly prevalent in HIV-positive populations, and may be more common than in HIV-negative populations. Risk factors contributing to the development of hypertension in PLHIV include demographic factors, genetic predisposition, lifestyle, comorbidities such as obesity, antiretroviral therapy-related changes in body composition, and potentially also immunodeficiency, immune activation and inflammation, as well as effects from antiretroviral therapy itself. Clinical management of hypertension in PLHIV requires awareness for drug-drug interactions between antiretroviral drugs and antihypertensive drugs. Awareness, treatment, and control of hypertension in PLHIV is currently suboptimal and should be improved.

SUMMARY

The burden of hypertension among PLHIV is high and its pathophysiology most likely multifactorial. Elucidating the exact pathophysiology of hypertension in PLHIV is vital as this may provide new targets to impact and improve clinical management. In the meantime, efforts should be made to improve hypertension management as per existing clinical guidelines in order to safeguard cardiovascular health and quality of life in PLHIV.

Association between CD4 Cell Count and Blood Pressure and Its Variation with Body Mass Index Categories in HIV-Infected Patients

The aim of this study was to establish whether an independent relationship exists between CD4 count and hypertension and if this relationship is modified or confounded by the body mass index (BMI). Methods. A secondary data analysis of a cross-sectional study on 200 HIV/AIDS patients at a referral hospital in Cameroon was conducted. Linear and logistic regression models were used as appropriate to explore the association between the variables of interest. Results. There was no linear association between log CD4 count and both systolic (p = 0.200; r = 0.12) and diastolic blood pressures (p = 0.123; r = 0.14), respectively. After adjusting for BMI, patients with CD4 count ≥ 350 cells/μl were more likely to have hypertension than those with CD4 count < 350 cells/μl (AOR: 2.50, 95% CI: 1.05–5.93, and p = 0.032). There was no effect modification from BMI (test of homogeneity, p = 0.721). There was no independent relationship between CD4 count and hypertension after controlling for age, sex, family history of hypertension, BMI-defined overweight, HAART use, and duration of HIV infection (AOR: 1.66, 95% CI: 0.48–5.71, and p = 0.419). Conclusion. This study did not identify any independent relationship between CD4 count and hypertension. Large prospective studies are recommended to better explore this relationship between hypertension and CD4 count.

Hypertension in HIV-Infected Adults Compared with Similar but Uninfected Adults in China: Body Mass Index-Dependent Effects of Nadir CD4 Count

Hypertension is a growing problem in the HIV population. The relationship between low nadir CD4 count and hypertension in the HIV-infected population has been reported. However, the effect of nadir CD4 on hypertension due to a different body mass index (BMI) is yet to be fully elucidated. In this cross-sectional study, 345 HIV-infected participants aged ≥40 years were recruited. They were frequency matched and compared with age, sex, and education with HIV-uninfected adults (n = 345). Hypertension prevalence was lower in HIV-infected than in HIV-uninfected participants (23.8% vs. 31.9%; p = .011), but this association was not significant after adjusting for potential confounders. Among HIV-infected individuals, older age, overweight, with a family history of cardiovascular diseases, and nadir CD4 count <50 cells/μl were independently associated with hypertension. Stratifying individuals with BMI category revealed that nadir CD4 count-regardless if it was operationalized as a dichotomous variable (<50 cells/μl) or continuous variable-was found to be associated with hypertension among individuals who were underweight and obese, but not among those who were normal weight and overweight. Among HIV-uninfected individuals, older age and having a waist circumference above cutoff were significantly associated with hypertension. This is one of the first studies to demonstrate that the association of nadir CD4 and hypertension is observed in underweight and obese HIV-infected patients. While these results suggest that the relationship between nadir CD4 count and hypertension might be mediated by body weight, future longitudinal studies will be needed to validate the findings, including its causal pathways.

Immune markers, diurnal blood pressure profile and cardiac function in virologically suppressed HIV-infected patients

PURPOSE

Non-dipping nocturnal blood pressure (BP) pattern has been reported prevalent among HIV-infected patients and is associated with adverse cardiovascular outcomes. The aims of this observational study were to identify predictors of nocturnal BP decline, and to explore whether diurnal BP profile is associated with alterations in cardiac structure and function.

MATERIALS AND METHODS

A total of 108 treated HIV-infected patients with suppressed viremia underwent ambulatory BP measurement, 51 of these patients also underwent echocardiography.

RESULTS

Non-dipping nocturnal BP pattern was present in 51% of the patients. Decreased nocturnal decline in systolic BP (SBP) correlated with lower CD4 count (r_sp = 0.21, p = 0.032) and lower CD4/CD8 ratio (r_sp = 0.26, p = 0.008). In multivariate linear regression analyses, lower BMI (p = 0.015) and CD4/CD8 ratio <0.4 (p = 0.010) remained independent predictors of nocturnal decline in SBP. Nocturnal decline in SBP correlated with impaired diastolic function, e' (r = 0.28, p = 0.049) as did nadir CD4 count (r_sp = 0.38, p = 0.006). In multivariate linear regression analyses, nadir CD4 count <100 cells/μL (p = 0.037) and age (p < 0.001) remained independent predictors of e'.

CONCLUSIONS

Compromised immune status may contribute to attenuated diurnal BP profile as well as impaired diastolic function in well-treated HIV infection.

D-Dimer Levels and Traditional Risk Factors Are Associated With Incident Hypertension Among HIV-Infected Individuals Initiating Antiretroviral Therapy in Uganda

OBJECTIVES

We sought to describe blood pressure (BP) changes after antiretroviral therapy (ART) initiation and evaluate the association of markers of inflammation with incident hypertension in a cohort of HIV-infected individuals in Uganda.

METHODS

We used mixed effects linear regression to model changes in systolic BP over time among a cohort of HIV-infected individuals initiating ART in Uganda. After exclusion of participants with preexisting hypertension, we identified participants with normal BP throughout follow-up (controls) and those with elevated BP on ≥3 consecutive visits (cases). Before ART initiation, participants had testing for interleukin 6, kynurenine/tryptophan ratio, lipopolysaccharide, soluble CD14, soluble CD163, and D-dimer and those with viral suppression at 6 months during ART had repeat tests. We fit logistic regression models to estimate associations between biomarkers and risk of incident hypertension.

RESULTS

In the entire cohort, systolic BP increased by 9.6 mm Hg/yr (95% CI: 7.3 to 11.8) in the first 6 months of ART, then plateaued. Traditional factors: male gender (adjusted odds ratio (AOR) 2.76, 95% CI: 1.34 to 5.68), age (AOR 1.09, 95% CI: 1.04 to 1.13), overweight (AOR 4.48, 95% CI: 1.83 to 10.97), and a CD4 count <100 cells (AOR 3.08, 95% CI: 1.07 to 8.89) were associated with incident hypertension. After adjusting for these, D-dimer levels at month 6 were inversely associated with incident hypertension (AOR 0.61, 95% CI: 0.37 to 0.99). Although not significant, similar associations were seen with sCD14 and kynurenine/tryptophan ratio.

CONCLUSION

BP increases early after ART initiation in Ugandans. Traditional risk factors, rather than immune activation, were associated with incident hypertension in this population.

Microbiome of HIV-infected people

Consistent interactions between the gut microbiome and adaptive immunity recently led several research groups to evaluate modifications of human gut microbiota composition during HIV infection. Herein we propose to review the shifts reported in infected individuals, as their correlation to disease progression. Though the gut microbiota is consistently altered in HIV individuals, the literature reveals several discrepancies, such as changes in microbial diversity associated with HIV status, taxa modified in infected subjects or influence of ART on gut flora restoration. Similarly, mechanisms involved in interactions between gut bacteria and immunity are to date poorly elucidated, emphasizing the importance of understanding how microbes can promote HIV replication. Further research is needed to propose adjuvant therapeutics dedicated to controlling disease progression through gut microbiome restoration.

Higher Prevalence of Hypertension in HIV-1-Infected Patients on Combination Antiretroviral Therapy Is Associated With Changes in Body Composition and Prior Stavudine Exposure

BACKGROUND

Individuals infected with human immunodeficiency virus (HIV) have a higher risk of cardiovascular disease, potentially partly mediated by a higher prevalence of hypertension. We therefore examined the prevalence and determinants of hypertension in HIV-1-infected patients compared with appropriate HIV-negative controls.

METHODS

Data from 527 HIV-1-infected and 517 HIV-uninfected participants at the time of enrollment into the ongoing AGEhIV Cohort Study were analyzed. Hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, and/or self-reported use of antihypertensive drugs.

RESULTS

Hypertension prevalence was higher among HIV-1-infected individuals compared with controls (48.2% vs 36.4%; odds ratio [OR], 1.63; 95% confidence interval [CI], 1.27-2.09). In logistic regression models adjusted for age, sex, ethnicity, family history of hypertension, smoking, alcohol use, physical activity, and body mass index, the association between HIV and hypertension remained statistically significant (ORHIV, 1.65; 95% CI, 1.25-2.19), but was attenuated after additional adjustment for waist-to-hip ratio (ORHIV, 1.29; 95% CI, .95-1.76). Among HIV-1-infected individuals, particularly among those with mono/dual nucleoside reverse transcriptase inhibitor therapy prior to combination antiretroviral therapy, stavudine exposure was independently associated with hypertension (ORstavudine, 1.54; 95% CI, 1.04-2.30). This association was attenuated after additional adjustment for either waist-to-hip ratio (ORstavudine, 1.30; 95% CI, .85-1.96) or hip circumference (ORstavudine, 1.40; 95% CI, .93-2.11).

CONCLUSIONS

Our findings suggest that changes in body composition, involving both abdominal obesity and stavudine-induced peripheral lipoatrophy, might contribute to the higher prevalence of hypertension in HIV-1-infected patients.

CLINICAL TRIALS REGISTRATION

NCT01466582.

Soluble CD14 in cerebrospinal fluid is associated with markers of inflammation and axonal damage in untreated HIV-infected patients: a retrospective cross-sectional study

Background

HIV-associated cognitive impairment has declined since the introduction of combination antiretroviral treatment (cART). However, milder forms of cognitive impairment persist. Inflammation in the cerebrospinal fluid (CSF) has been associated with cognitive impairment, and CSF neurofilament light chain protein (NFL) and CSF neopterin concentrations are increased in those patients. Microbial translocation in HIV infection has been suggested to contribute to chronic inflammation, and lipopolysaccharide (LPS) and soluble CD14 (sCD14) are markers of microbial translocation and the resulting monocyte activation, respectively. We hypothesised that microbial translocation contributes to inflammation and axonal damage in the central nervous system (CNS) in untreated HIV infection.

Methods

We analyzed paired samples of plasma and CSF from 62 HIV-infected, untreated patients without cognitive symptoms from Sahlgrenska University Hospital, Gothenburg, Sweden. Measurements of neopterin and NFL in CSF were available from previous studies. Plasma and CSF sCD14 was measured using ELISA (R&D, Minneapolis, MN), and plasma and CSF LPS was measured using LAL colorimetric assay (Lonza, Walkersville, MD, USA). Univariate and multivariate regression analyses were performed.

Results

LPS in plasma was associated with plasma sCD14 (r = 0.31, P = 0.015), and plasma sCD14 was associated with CSF sCD14 (r = 0.32, P = 0.012). Furthermore, CSF sCD14 was associated with NFL (r = 0.32, P = 0.031) and neopterin (r = 0.32, P = 0.012) in CSF. LPS was not detectable in CSF. In a multivariate regression model CSF sCD14 remained associated with NFL and neopterin after adjusting for age, CD4+ cell count, and HIV RNA in CSF.

Conclusions

In a group of untreated, HIV-infected patients LPS was associated with sCD14 in plasma, and plasma sCD14 was associated CSF sCD14. CSF sCD14 were associated with markers of CNS inflammation and axonal damage. This suggest that microbial translocation might be a driver of systemic and CNS inflammation. However, LPS was not detectable in the CSF, and since sCD14 is a marker of monocyte activation sCD14 may be increased due to other causes than microbial translocation. Further studies regarding cognitive impairment and biomarkers are warranted to fully understand causality.

Elevated Soluble CD14 and Lower D-Dimer Are Associated With Cigarette Smoking and Heavy Episodic Alcohol Use in Persons Living With HIV

BACKGROUND

Persons living with HIV are at increased risk for cardiovascular disease in part because of persistent inflammation and coagulation activation.

METHODS

We examined whether smoking and heavy episodic alcohol use (defined as 5 or more drinks on one occasion) were associated with greater monocyte activation (soluble CD14) and coagulation (D-dimer) in participants in the Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (the "SUN" Study), a prospective observational cohort.

RESULTS

Using regression analysis (n = 689), current smoking compared with nonsmoking was associated with significantly elevated soluble CD14 (B = 135.57, 95% confidence interval: 84.95 to 186.19, P < 0.001), whereas heavy alcohol use compared with nonheavy use was associated with significantly lower D-dimer levels (B = -0.059, 95% confidence interval: -0.102 to -0.016, P = 0.007).

CONCLUSIONS

Smoking cessation should be encouraged by HIV care providers to improve mortality outcomes from all causes of death, particularly cardiovascular disease.

Monocyte activation, but not microbial translocation, is independently associated with markers of endovascular dysfunction in HIV-infected patients receiving cART

BACKGROUND

Microbial translocation has been suggested as a driver of cardiovascular disease in HIV infection. We hypothesized that microbial translocation and the resulting monocyte activation would be associated with markers of endovascular dysfunction.

METHODS

In 60 HIV-infected patients on combination antiretroviral therapy, plasma levels of lipopolysaccharide, soluble CD14 (sCD14), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) were measured.

RESULTS

ADMA and SDMA were associated with sCD14 but not lipopolysaccharide. There was a significant increase in ADMA and SDMA through tertiles of sCD14, and both markers were associated with sCD14 in multivariate linear regression analyses.

CONCLUSIONS

Monocyte activation as measured by sCD14 is associated with endovascular dysfunction in HIV infection.

Soluble CD14 is associated with markers of vascular dysfunction in bariatric surgery patients

BACKGROUND

Chronic endotoxemia has been proposed to contribute to obesity-related complications. We aimed to investigate the potential impact of lipopolysaccharide (LPS) and subsequent monocyte activation measured as soluble CD14 (sCD14) on markers of vascular dysfunction in obese subjects undergoing bariatric surgery.

METHODS

This was a prospective study of 49 obese patients and 17 controls, assessed by plasma levels of LPS, sCD14, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA).

RESULTS

Levels of ADMA were increased in obese subjects compared to controls, but were not significantly reduced after bariatric surgery. In obese subjects at baseline, there was a significant trend to increasing levels of ADMA and SDMA through tertiles of sCD14 and decreasing levels of both markers through tertiles of LPS. In models adjusting for age and gender, sCD14 but not LPS remained independently associated with ADMA and SDMA. For every 10% age- and gender-adjusted increase in sCD14, ADMA increased 0.031 μM (5.6%), whereas SDMA increased 0.039 μM (10.8%).

CONCLUSIONS

Our results suggest that monocyte activation as measured by sCD14 is associated with obesity-related vascular dysfunction, whereas potential upstream triggers including microbial products should be investigated in future studies.

Inflammatory co-morbidities in HIV+ individuals: learning lessons from healthy ageing

Increased life expectancy due to improved efficacy of cART has uncovered an increased risk of age-related morbidities in HIV+ individuals and catalyzed significant research into mechanisms driving these diseases. HIV infection increases the risk of non-communicable diseases common in the aged, including cardiovascular disease, neurocognitive decline, non-AIDS malignancies, osteoporosis, and frailty. These observations suggest that HIV accelerates immunological ageing, and there are many immunological similarities with the aged, including shortened telomeres, accumulation of senescent T cells and altered monocyte phenotype/function. However, the most critical similarity between HIV+ individuals and the elderly, which most likely underpins the heightened risk of non-communicable diseases, is chronic inflammation and associated immune activation. Here, we review the similarities between HIV+ individuals and the aged regarding the pathogenesis of inflammatory diseases, the current evidence for mechanisms driving these processes and discuss current and potential therapeutic strategies for addressing inflammatory co-morbidity in HIV+ infection.

Gut Microbiota in HIV Infection: Implication for Disease Progression and Management

Survival rates among HIV patients have significantly improved since the introduction of antiretroviral therapy (ART) in HIV management. However, persistent disease progression and clinical complications in virally suppressed individuals point to additional contributing factors other than HIV replication; microbial translocation is one such factor. The role of underlying commensal microbes and microbial products that traverse the intestinal lumen into systemic circulation in the absence of overt bacteraemia is under current investigation. This review focuses on current knowledge of the complex microbial communities and microbial markers involved in the disruption of mucosal immune T-cells in the promotion of inflammatory processes in HIV infections. Unanswered questions and aims for future studies are addressed. We provide perspective for discussing potential future therapeutic strategies focused on modulating the gut microbiota to abate HIV disease progression.

Microbial translocation and cardiometabolic risk factors in HIV infection

The widespread access to antiretroviral treatment during the past decades has transformed HIV infection from a lethal disease to a chronic condition, in which the relative burden of non-AIDS-related chronic disorders such as cardiovascular disease, malignancy, renal, liver, and bone disease has increased. The adjusted relative risk for myocardial infarction is reported to be around 2-fold compared to that of the general population, which over time is likely to translate into increased absolute risk in an aging population. Thus, delineating potentially HIV-specific pathogenetic mechanisms is crucial in order to tailor novel strategies for prophylaxis and treatment. This review will focus on advances in the field that possibly link HIV-induced alterations of the gut mucosa and consequent microbial translocation to cardiometabolic risk factors in HIV infection. Recent work suggests that markers of microbial translocation are closely associated with several cardiovascular risk factors such as dyslipidemia, insulin resistance, hypertension, coagulation abnormalities, endothelial dysfunction, and carotid atherosclerosis. Future studies should investigate whether associations between microbial translocation and cardiovascular risk factors will translate into increased risk of acute events, and whether strategies to target gut microbiota and microbial translocation might reduce such a risk.

Switch to raltegravir decreases soluble CD14 in virologically suppressed overweight women: the Women, Integrase and Fat Accumulation Trial

OBJECTIVES

Soluble CD14 (sCD14) is a monocyte activation marker associated with increased mortality in HIV infection. We assessed 48-week changes in sCD14 and other inflammatory biomarkers in virologically suppressed, HIV-infected women switching to raltegravir (RAL) from a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI).

METHODS

HIV-infected women with central adiposity and HIV-1 RNA < 50 HIV-1 RNA copies/mL continued their thymidine-sparing nucleoside reverse transcriptase inhibitor (NRTI) backbone and were randomized to switch to open-label RAL at week 0 (immediate) or 24 (delayed). In an exploratory analysis, inflammatory biomarkers were measured on stored fasting plasma.

RESULTS

Of the 37 evaluable subjects, 78% were non-White; the median age was 43 years, the median body mass index (BMI) was 32 kg/m(2) and the median CD4 count was 558 cells/μL. At baseline, biomarker values were similar between groups. After 24 weeks, median sCD14 significantly declined in subjects switching to RAL [-21% (P < 0.001) vs. PI/NNRTI -5% (P = 0.49); between-group P < 0.01]. After 48 weeks, immediate-switch subjects maintained this decline and delayed-switch subjects experienced a similar decline following the switch to RAL (-10%; within-group P < 0.01). Immediate-switch subjects also experienced an initial increase in tumour necrosis factor (TNF)-α that was neither maintained after 48 weeks nor seen in delayed-switch subjects. After adjustment for multiple testing, only declines in sCD14 remained significant.

CONCLUSIONS

In this randomized trial of women with central adiposity, a switch to RAL from a PI or NNRTI was associated with a statistically significant decline in sCD14. Further studies are needed to determine whether integrase inhibitors have improved monocyte activation profiles compared with PIs and/or NNRTIs, and whether measured differences between antiretroviral agents translate to demonstrable clinical benefit.