Exposure to HIV-1 directly impairs mucosal epithelial barrier integrity allowing microbial translocation. PLoS Pathog. 2010;6:e1000852. [PMID: 20386714 PMCID: PMC2851733 DOI: 10.1371/journal.ppat.1000852]

The Influence of Cervicovaginal Microbiota on Mucosal Immunity and Prophylaxis in the Battle against HIV

PURPOSE OF REVIEW

Young women in sub-Saharan Africa bear a disproportionate burden of the global HIV epidemic. In this review, we examine how cervicovaginal microbiota modulate structural and immune defenses in the female genital tract and influence HIV susceptibility.

RECENT FINDINGS

Highly diverse, anaerobic cervicovaginal microbiota prevalent in sub-Saharan African women increase HIV acquisition risk by over fourfold. These bacteria weaken the barrier properties of the vaginal mucosa and increase local inflammation and HIV target cell recruitment, creating an environment permissive to HIV. These communities also diminish the prophylactic efficacy of topical tenofovir and therefore may modulate both biological susceptibility to HIV and the effectiveness of pre-exposure prophylaxis (PrEP). Cervicovaginal bacteria influence multiple reproductive health outcomes, including HIV acquisition. High-diversity, low Lactobacillus abundance cervicovaginal communities prevalent in many regions with high HIV incidence are associated with increased HIV susceptibility. A better understanding of the host-microbial interactions mediating this risk is important to reduce HIV infections, particularly among women living in sub-Saharan Africa.

Inflammation Strikes Again: Frailty and HIV

PURPOSE OF REVIEW

As a consequence of antiretroviral therapy, the proportion of older HIV-infected adults is increasing, with a concomitant shift in burden of illness to age-related syndromes and disease. Frailty is an age-related syndrome of increased vulnerability to stress, predictive of major adverse clinical outcomes among HIV-infected and uninfected persons alike. Understanding frailty pathogenesis is critical to developing interventions to improve health outcomes in HIV. Here, we review the current evidence for the relationship between inflammation and frailty in HIV, and the potential for novel, inflammation-targeted interventions.

RECENT FINDINGS

Dysregulated inflammation has been consistently associated with frailty in elderly HIV-uninfected persons. Dysregulated inflammation is also central to HIV pathophysiology and several recent studies have demonstrated the important association of inflammation with frailty in HIV. Some evidence suggests that anti-inflammatory therapies may be effective in ameliorating the adverse impact of frailty among aging HIV-infected adults, though further investigation is necessary. Inflammation has been implicated in frailty in HIV infection, and improved understanding of the role that inflammation plays in frailty pathogenesis is key to the development of effective therapies to slow or prevent frailty in the vulnerable HIV-infected population.

Oral and anal high-risk human papilloma virus infection in HIV-positive men who have sex with men over a 24-month longitudinal study: complexity and vaccine implications

Background

Few studies focused on longitudinal modifications over time of high-risk HPV (HR-HPV) at anal and oral sites in HIV+ men who have sex with men (MSM).

Methods

We described patterns and longitudinal changes of HR-HPV detection and the prevalence of HR-HPV covered by the nonavalent HPV vaccine (vax-HPV) at oral and anal sites in 165 HIV+ MSM followed in an Italian hospital. The samples were collected at baseline and after 24 months (follow-up). The presence of HPV was investigated with Inno-LiPA HPV Genotyping Extra II.

Results

Median age was 44 years (IQR 36–53), median CD4+ cell count at nadir was 312 cells/mm³ (IQR 187–450). A total of 120 subjects (72.7%) were receiving successful antiretroviral therapy (ART). At baseline and follow-up, the frequency of HR-HPV was significantly higher in the anal site (65.4% vs 9.4 and 62.4% vs 6.8%, respectively). Only 2.9% of subjects were persistently HR-HPV negative at both sites. All oral HR-HPV were single at baseline vs 54.6% at baseline at the anal site (p = 0.005), and all oral HR-HPV were single at follow-up vs 54.4% at anal site at follow-up (p = 0.002). The lowest rate of concordance between the oral and anal results was found for HR-HPV detection; almost all HR-HPV positive results at both anal and oral sites had different HR-HPV.The most frequent HR-HPV in anal swabs at baseline and follow-up were HPV-16 and HPV-52.At follow-up at anal site, 37.5% of patients had different HR-HPV genotypes respect to baseline, 28.8% of subjects with 1 HR-HPV at baseline had an increased number of HR-HPV, and patients on ART showed a lower frequency of confirmed anal HR-HPV detection than untreated patients (p = 0.03) over time. Additionally,54.6 and 50.5% of patients had only HR-vax-HPV at anal site at baseline and follow-up, respectively; 15.2% had only HR-vax-HPV at baseline and follow-up.

Conclusions

We believe that it is important testing multiple sites over time in HIV-positive MSM. ART seems to protect men from anal HR-HPV confirmed detection. Vaccination programmes could reduce the number of HR-HPV genotypes at anal site and the risk of the first HR-HPV acquisition at the oral site.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7004-x) contains supplementary material, which is available to authorized users.

Distinct gut microbiota profile in antiretroviral therapy-treated perinatally HIV-infected patients associated with cardiac and inflammatory biomarkers

OBJECTIVE

Persistent inflammation and higher risk to develop cardiovascular diseases still represent a major complication for HIV-infected patients despite effective antiretroviral therapy (ART). We investigated the correlation between the gut microbiota profile, markers of inflammation, vascular endothelial activation (VEA) and microbial translocation (MT) in perinatally HIV-infected patients (PHIV) under ART.

DESIGN

Cross-sectional study including 61 ART-treated PHIV (age range 3-30 years old) and 71 age-matched healthy controls. Blood and stool sample were collected at the same time and analyzed for gut microbiota composition and plasma biomarkers.

METHODS

Gut microbiota composition was determined by 16S rRNA targeted-metagenomics. Soluble markers of MT, inflammation and VEA were quantified by ELISA or Luminex assay. Markers of immune activation were analyzed by flow cytometry on CD4 and CD8T cells.

RESULTS

We identified two distinct gut microbiota profiles (groups A and B) among PHIV. No different clinical parameters (age, sex, ethnicity, clinical class), dietary and sexual habits were found between the groups. The group A showed a relative dominance of Akkermansia muciniphila, whereas gut microbiota of group B was characterized by a higher biodiversity. The analysis of soluble markers revealed a significantly higher level of soluble E-selectine (P = 0.0296), intercellular adhesion molecule-1 (P = 0.0028), vascular adhesion molecule-1 (P = 0.0230), IL-6 (P = 0.0247) and soluble CD14 (P = 0.0142) in group A compared with group B.

CONCLUSION

Distinctive gut microbiota profiles are differently associated with inflammation, microbial translocation and VEA. Future studies are needed to understand the role of A. muciniphila and risk to develop cardiovascular diseases in PHIV.

Fungal Translocation Is Associated with Immune Activation and Systemic Inflammation in Treated HIV

The mechanisms causing HIV-associated immune activation remain incompletely understood. Alteration of intestinal integrity with subsequent translocation of bacterial products appears to play an important role; however, little is known about the impact of fungal translocation. We assessed the effect of fungal translocation and its association with immune activation in people living with HIV (PLWH) compared with uninfected controls. We measured serum levels of β-D-glucan (BDG) and anti-Saccharomyces cerevisiae antibodies (ASCA) immunoglobulin G (IgG) and immunoglobulin A (IgA) and markers of systemic inflammation and immune activation in virally suppressed PLWH on antiretroviral therapy (ART) and uninfected controls. T-test and Mann-Whitney tests were used to compare markers by HIV status and correlation and regression analyses were used to assess associations of fungal translocation markers with markers of inflammation. One hundred seventy-six participants were included (128 HIV+ and 48 HIV-); 72% male, 65% African American, median age was 50 years, and CD4 was 710 cells/cm³. Levels of BDG tended to be lower in HIV+ when compared with controls (p = .05). No significant difference in levels of ASCA IgG and IgA was seen between groups (p > .75). There was a significant correlation between BDG and several markers of inflammation and immune activation in PLWH, not seen in uninfected controls. In contrast, no correlations were seen between levels of ASCA IgG and IgA with inflammatory markers. PLWH on ART do not have higher levels of BDG or ASCA when compared with uninfected controls, however, the association found between BDG and several inflammation markers suggests a potential role of fungal translocation in the heightened immune activation seen in treated HIV.

The genital tract and rectal microbiomes: their role in HIV susceptibility and prevention in women

INTRODUCTION

Young women in sub-Saharan Africa are disproportionately affected by HIV, accounting for 25% of all new infections in 2017. Several behavioural and biological factors are known to impact a young woman's vulnerability for acquiring HIV. One key, but lesser understood, biological factor impacting vulnerability is the vaginal microbiome. This review describes the vaginal microbiome and examines its alterations, its influence on HIV acquisition as well as the efficacy of HIV prevention technologies, the role of the rectal microbiome in HIV acquisition, advances in technologies to study the microbiome and some future research directions.

DISCUSSION

Although the composition of each woman's vaginal microbiome is unique, a microbiome dominated by Lactobacillus species is generally associated with a "healthy" vagina. Disturbances in the vaginal microbiota, characterized by a shift from a low-diversity, Lactobacillus-dominant state to a high-diversity non-Lactobacillus-dominant state, have been shown to be associated with a range of adverse reproductive health outcomes, including increasing the risk of genital inflammation and HIV acquisition. Gardnerella vaginalis and Prevotella bivia have been shown to contribute to both HIV risk and genital inflammation. In addition to impacting HIV risk, the composition of the vaginal microbiome affects the vaginal concentrations of some antiretroviral drugs, particularly those administered intravaginally, and thereby their efficacy as pre-exposure prophylaxis (PrEP) for HIV prevention. Although the role of rectal microbiota in HIV acquisition in women is less well understood, the composition of this compartment's microbiome, particularly the presence of species of bacteria from the Prevotellaceae family likely contribute to HIV acquisition. Advances in technologies have facilitated the study of the genital microbiome's structure and function. While next-generation sequencing advanced knowledge of the diversity and complexity of the vaginal microbiome, the emerging field of metaproteomics, which provides important information on vaginal bacterial community structure, diversity and function, is further shedding light on functionality of the vaginal microbiome and its relationship with bacterial vaginosis (BV), as well as antiretroviral PrEP efficacy.

CONCLUSIONS

A better understanding of the composition, structure and function of the microbiome is needed to identify opportunities to alter the vaginal microbiome and prevent BV and reduce the risk of HIV acquisition.

HIV Infection, HCV Coinfection, and Alcohol Use: Associations with Microbial Translocation and Immune Activation

BACKGROUND

Human immunodeficiency virus (HIV) infection and heavy drinking independently promote microbial translocation and inflammation. However, it is not known how alcohol use may affect these processes in people living with HIV (PLWH). This study tested the hypothesis that alcohol exacerbates innate immune dysfunction in PLWH.

METHODS

Participants were 75 PLWH and 34 uninfected controls. Groups were recruited to have similar proportions of nondrinkers, moderate drinkers, and heavy drinkers. Substance use data and plasma samples were collected at up to 3 visits over a 5-year study period. Recent alcohol use was assessed with the Timeline Followback Interview. Biomarkers of microbial translocation (lipopolysaccharide, LPS) and immune activation (lipopolysaccharide binding protein, LBP; soluble CD14, sCD14; soluble CD163, sCD163) were quantified using enzyme-linked immunosorbent assays. Analyses tested 2 hypotheses: (i) that biomarker levels would be significantly higher in PLWH than controls with comparable alcohol use and (ii) that current alcohol use would exacerbate biomarker elevations in PLWH. The second analysis included the interaction of alcohol use with hepatitis C virus (HCV) coinfection.

RESULTS

Groups were matched on alcohol use, smoking, and other drug use. All biomarkers were significantly higher in PLWH relative to controls (LBP: p = 0.005; LPS: p = 0.014; sCD14: p < 0.001; sCD163: p < 0.001). In PLWH, alcohol use showed a significant, positive association with sCD163, but not with other biomarkers. However, the interaction of alcohol use with HCV coinfection was significant for all biomarkers (LBP: p = 0.002; LPS: p = 0.026; sCD14: p = 0.0004; sCD163: p = 0.001). In pairwise tests with sequential Bonferroni correction, HIV/HCV coinfected individuals who drank heavily had significantly higher sCD163 compared to coinfected nondrinkers and to HIV monoinfected nondrinkers, moderate drinkers, and heavy drinkers (ps < 0.005). Coinfected moderate drinkers had significantly higher sCD163 than each monoinfected group (ps < 0.003). In addition, sCD14 was significantly higher in coinfected moderate drinkers than coinfected nondrinkers (p = 0.027).

CONCLUSIONS

As predicted, PLWH had higher levels of LBP, LPS, sCD14, and sCD163 than uninfected individuals with similar alcohol use. In PLWH, alcohol by itself was significantly associated only with higher sCD163. However, heavy or moderate alcohol use was associated with elevations in macrophage activation (sCD163) and monocyte activation (sCD14) in HIV/HCV coinfected individuals.

Lower Pretreatment Gut Integrity Is Independently Associated With Fat Gain on Antiretroviral Therapy

BACKGROUND

Fat accumulation and insulin resistance remain a threat to the success of antiretroviral therapy (ART). The role of gut dysfunction in metabolic complications associated with ART initiation is unclear.

METHODS

Human immunodeficiency virus (HIV)-infected ART-naive participants were randomized to tenofovir disoproxil fumarate/emtricitabine plus atazanavir/ritonavir, darunavir/ritonavir, or raltegravir (RAL). Changes in the gut integrity markers zonulin, lipopolysaccharide-binding protein (LBP), and intestinal fatty acid and ileal bile acid binding proteins (I-FABP and I-BABP) were assessed over 96 weeks. Wilcoxon rank-sum tests were used to compare changes between groups and linear regression models to quantify associations between gut markers, insulin resistance, body mass index (BMI), and visceral, subcutaneous, and total adipose tissue (VAT, SAT, and TAT).

RESULTS

: 90% were male and 48% were White non-Hispanic. The median age was 36 years, HIV-1 ribonucleic acid was 4.56 log10 copies/mL, and CD4 count was 338 cells/µL. An overall 1.7-fold increase in I-FABP was observed throughout 96 weeks, with no difference between arms. Zonulin levels increased with RAL compared to protease inhibitor-based regimens (week 96, P = .02); minimal changes in I-BABP or LBP levels were observed. Higher baseline I-FABP levels were associated with increases in VAT, TAT, and BMI (16%, 9%, and 2.5%, respectively; P < .04) over 96 weeks.

CONCLUSIONS

While ART induces changes in the markers of gut barrier dysfunction, the extent to which they improve or worsen the gut barrier function remains unclear. Nevertheless, markers of gut barrier dysfunction in ART-naive individuals predict increases in total and visceral abdominal fat with treatment initiation.

IL-17A and IL-17F repair HIV-1 gp140 damaged Caco-2 cell barriers by upregulating tight junction genes

It is widely accepted that impairment of the intestinal epithelial barrier from HIV/AIDS contributes significantly to microbial translocation and systemic immune activation. Such factors present potential targets for novel treatments aimed toward a functional cure. However, the extracellular mechanisms of intestinal barrier repair are poorly understood. In the current study, we investigated the abilities of IL-17A and IL-17F to repair the damaged barrier caused by HIV-1 gp140 using Caco-2 monolayers. It was found that HIV-1 gp140 downregulated the expression of tight junction-associated genes and disrupted the barrier integrity of Caco-2 monolayers. However, IL-17A and IL-17F treatment reversed the HIV-1 gp140-induced barrier dysfunction by upregulating the expression of tight junction-associated genes, the combination of which resulted in a stronger induction of barrier repair. Furthermore, the effects of IL-17A and IL-17F were reduced by downregulation of Act1 with siRNA and inhibition of NF-κB and MAPK pathways with BAY11-7082 and U0126, respectively. These data indicated that the NF-κB and MAPK pathways are involved in the repair of barrier integrity mediated by IL-17A and IL-17F, and IL-17 pathways are potential targets for gut barrier restoration therapies during HIV/AIDS.

Biomarkers of aging in HIV: inflammation and the microbiome

PURPOSE

HIV-infected subjects present increased levels of inflammatory cytokines and T cell activation in the peripheral blood despite suppressive combination antiretroviral therapy which renders them susceptible to premature aging. The purpose of the present work was to review existing evidence on the ways in which the anatomical and microbiological abnormalities of the gastrointestinal tract can represent a major cause of organ disease in HIV infection.

METHODS

We conducted a systematic review of the Pubmed database for articles published from 2014 to 2018. We included studies on inflammatory/activation biomarkers associated with cardiovascular and bone disease, neurocognitive impairment and serious non-AIDS events in HIV-infected subjects. We also included researches which linked peripheral inflammation/activation to the anatomical, immune and microbiological alterations of the gastrointestinal tract.

RESULTS

Recent literature data confirm the association between non-infectious comorbidities and inflammation in HIV infection which may be driven by gastrointestinal tract abnormalities, specifically microbial translocation and dysbiosis. Furthermore, there is mounting evidence on the possible role of metabolic functions of the microbiota in the pathogenesis of premature aging in the HIV-infected population.

CONCLUSIONS

Biomarkers need to be validated for their use in the management of HIV infection. Compounds which counteract microbial translocation, inflammation and dysbiosis have been investigated as alternative therapeutic strategies in viro-suppressed HIV-infected individuals, but appear to have limited efficacy, probably due to the multifactorial pathogenesis of non-infectious comorbidities in this setting.

Surfactant Protein D Reverses the Gene Signature of Transepithelial HIV-1 Passage and Restricts the Viral Transfer Across the Vaginal Barrier

Effective prophylactic strategy against the current epidemic of sexually transmitted HIV-1 infection requires understanding of the innate gatekeeping mechanisms at the genital mucosa. Surfactant protein D (SP-D), a member of the collectin family of proteins naturally present in the vaginal tract, is a potential HIV-1 entry inhibitor at the cellular level. Human EpiVaginal tissues compartmentalized in culture inserts were apically exposed to HIV-1 and/or a recombinant fragment of human SP-D (rfhSP-D) and viral passage was assessed in the basal chamber containing mononuclear leukocytes. To map the gene signature facilitating or resisting the transepithelial viral transfer, microarray analysis of the HIV-1 challenged EpiVaginal tissues was performed in the absence or presence of rfhSP-D. Mucosal biocompatibility of rfhSP-D was assessed ex vivo and in the standard rabbit vaginal irritation model. The passage of virus through the EpiVaginal tissues toward the underlying target cells was associated with a global epithelial gene signature including differential regulation of genes primarily involved in inflammation, tight junctions and cytoskeletal framework. RfhSP-D significantly inhibited HIV-1 transfer across the vaginal tissues and was associated with a significant reversal of virus induced epithelial gene signature. Pro-inflammatory NF-κB and mTOR transcripts were significantly downregulated, while expression of the tight junctions and cytoskeletal genes was upheld. In the absence of virus, rfhSP-D directly interacted with the EpiVaginal tissues and upregulated expression of genes related to structural stability of the cell and epithelial integrity. There was no increment in the viral acquisition by the PBMCs present in basal chambers wherein, the EpiVaginal tissues in apical chambers were treated with rfhSP-D. The effective concentrations of rfhSP-D had no effect on lactobacilli, epithelial barrier integrity and were safe on repeated applications onto the rabbit vaginal mucosa. This pre-clinical safety data, coupled with its efficacy of restricting viral passage via reversal of virus-induced gene expression of the vaginal barrier, make a strong argument for clinical trials of rfhSP-D as a topical anti-HIV microbicide.

TLR10 Senses HIV-1 Proteins and Significantly Enhances HIV-1 Infection

Toll-like receptors (TLRs) play a crucial role in innate immunity and provide a first line of host defense against invading pathogens. Of the identified human TLRs, TLR10 remains an orphan receptor whose ligands and functions are poorly understood. In the present study, we sought to evaluate the level of TLR10 expression in breast milk (BM) and explore its potential function in the context of HIV-1 infection. We evaluated HIV-1-infected (Nigerian: n = 40) and uninfected (Nigerian: n = 27; Canadian: n = 15) BM samples for TLR expression (i.e., TLR10, TLR2, and TLR1) and report here that HIV-1-infected BM from Nigerian women showed significantly higher levels of TLR10, TLR1, and TLR2 expression. Moreover, the level of TLR10 expression in HIV-1-infected BM was upregulated by over 100-fold compared to that from uninfected control women. In vitro studies using TZMbl cells demonstrated that TLR10 overexpression contributes to higher HIV-1 infection and proviral DNA integration. Conversely, TLR10 inhibition significantly decreased HIV-1 infection. Notably, HIV-1 gp41 was recognized as a TLR10 ligand, leading to the induction of IL-8 and NF-κBα activation. The identification of a TLR10 ligand and its involvement in HIV-1 infection enhances our current understanding of HIV-1 replication and may assist in the development of improved future therapeutic strategies.

Gut microbiota in HIV-pneumonia patients is related to peripheral CD4 counts, lung microbiota, and in vitro macrophage dysfunction

Pneumonia is common and frequently fatal in HIV-infected patients, due to rampant, systemic inflammation and failure to control microbial infection. While airway microbiota composition is related to local inflammatory response, gut microbiota has been shown to correlate with the degree of peripheral immune activation (IL6 and IP10 expression) in HIV-infected patients. We thus hypothesized that both airway and gut microbiota are perturbed in HIV-infected pneumonia patients, that the gut microbiota is related to peripheral CD4+ cell counts, and that its associated products differentially program immune cell populations necessary for controlling microbial infection in CD4-high and CD4-low patients. To assess these relationships, paired bronchoalveolar lavage and stool microbiota (bacterial and fungal) from a large cohort of Ugandan, HIV-infected patients with pneumonia were examined, and in vitro tests of the effect of gut microbiome products on macrophage effector phenotypes performed. While lower airway microbiota stratified into three compositionally distinct microbiota as previously described, these were not related to peripheral CD4 cell count. In contrast, variation in gut microbiota composition significantly related to CD4 cell count, lung microbiota composition, and patient mortality. Compared with patients with high CD4+ cell counts, those with low counts possessed more compositionally similar airway and gut microbiota, evidence of microbial translocation, and their associated gut microbiome products reduced macrophage activation and IL-10 expression and increased IL-1β expression in vitro. These findings suggest that the gut microbiome is related to CD4 status and plays a key role in modulating macrophage function, critical to microbial control in HIV-infected patients with pneumonia.

Immune Activation, Inflammation, and Non-AIDS Co-Morbidities in HIV-Infected Patients under Long-Term ART

Despite effective antiretroviral therapy (ART), people living with HIV (PLWH) still present persistent chronic immune activation and inflammation. This condition is the result of several factors including thymic dysfunction, persistent antigen stimulation due to low residual viremia, microbial translocation and dysbiosis, caused by the disruption of the gut mucosa, co-infections, and cumulative ART toxicity. All of these factors can create a vicious cycle that does not allow the full control of immune activation and inflammation, leading to an increased risk of developing non-AIDS co-morbidities such as metabolic syndrome and cardiovascular diseases. This review aims to provide an overview of the most recent data about HIV-associated inflammation and chronic immune exhaustion in PLWH under effective ART. Furthermore, we discuss new therapy approaches that are currently being tested to reduce the risk of developing inflammation, ART toxicity, and non-AIDS co-morbidities.

Beneficial effects of Saccharomyces boulardii CNCM I-745 on clinical disorders associated with intestinal barrier disruption

Intestinal barrier defects lead to "leaky gut syndrome", defined as an increase in intestinal permeability that allows the passage of luminal content into intestinal tissue and the bloodstream. Such a compromised intestinal barrier is the main factor underlying the pathogenesis of inflammatory bowel disease, but also commonly occurs in various systemic diseases such as viral infections and metabolic syndrome. The non-pathogenic yeast Saccharomyces boulardii CNCM I-745 has demonstrated its effectiveness as a probiotic in the prevention and treatment of antibiotic-associated, infectious and functional diarrhea. Via multiple mechanisms of action implicated in intestinal barrier function, S. boulardii has beneficial effects on altered intestinal microbiota and epithelial barrier defects in different pathologies. The well-studied probiotic yeast S. boulardii plays a crucial role in the preservation and/or restoration of intestinal barrier function in multiple disorders. This could be of major interest in diseases characterized by alterations in intestinal barrier function.

Mucosa: Key Interactions Determining Sexual Transmission of the HIV Infection

In the context of HIV sexual transmission at the genital mucosa, initial interactions between the virus and the mucosal immunity determine the outcome of the exposure. Hence, these interactions have been deeply explored in attempts to undercover potential targets for developing preventative strategies. The knowledge gained has led to propose a hypothetical model for mucosal HIV transmission. Subsequent research studies on this topic further revealed new mechanisms and identified new host-HIV interactions. This review aims at integrating these findings to inform better and update the current model of HIV transmission. At the earliest stage of virus exposure, the epithelial integrity and the presence of antiviral factors are critical in preventing viral entry to the submucosa. However, the virus has been shown to enter to the submucosa in the presence of physical abrasion or via epithelial transmigration using paracellular passage or transcytosis mechanisms. The efficiency of these processes is greater with cell-associated viral inoculums and can be influenced by the presence of viral and immune factors, and by the structure of the exposed epithelium. Once the virus reaches the submucosa, dendritic cells and fibroblasts, as recently described, have been shown in vitro of being capable of facilitating the transfer of viral particles to susceptible cells, leading to viral dissemination, most likely in a trans-infection manner. The presence of activated CD4⁺ T cells in submucosa increases the probability of infection, where the predominant microbiota could be implicated through the modulation of an inflammatory microenvironment. Other factors such as genital fluids and hormones could also play an essential role in HIV transmission. Here, we review the most recent evidence described for mucosal HIV-transmission contributing with the understanding of this phenomenon.

Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on stunting and anaemia among HIV-exposed children in rural Zimbabwe: a cluster-randomised controlled trial

BACKGROUND

Children exposed to HIV have a high prevalence of stunting and anaemia. We aimed to test the effect of improved infant and young child feeding (IYCF) and improved water, sanitation, and hygiene (WASH) on child linear growth and haemoglobin concentrations.

METHODS

We did a cluster randomised 2 × 2 factorial trial in two districts in rural Zimbabwe. Women were eligible for inclusion if they permanently lived in the trial clusters (ie, the catchment area of between one and four village health workers employed by the Zimbabwean Ministry of Health and Child Care) and were confirmed pregnant. Clusters were randomly allocated to standard of care (52 clusters); IYCF (20 g small-quantity lipid-based nutrient supplement daily for infants from 6 months to 18 months, complementary feeding counselling with context-specific messages, longitudinal delivery, and reinforcement; 53 clusters); WASH (ventilated, improved pit latrine, two hand-washing stations, liquid soap, chlorine, play space, and hygiene counselling; 53 clusters); or IYCF plus WASH (53 clusters). Participants and fieldworkers were not masked. Our co-primary outcomes were length for age Z score and haemoglobin in infants at 18 months of age. Here, we report these outcomes in the HIV-exposed children, analysed by intention to treat. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes with an important statistical interaction between the interventions. The trial is registered at ClinicalTrials.gov (NCT01824940) and is now complete.

FINDINGS

Between Nov 22, 2012, and March 27, 2015, 726 HIV-positive pregnant women were included in the trial. 668 children were evaluated at 18 months (147 from 46 standard of care clusters; 147 from 48 IYCF clusters; 184 from 44 WASH clusters; 190 from 47 IYCF plus WASH clusters). Of the 668 children, 22 (3%) were HIV-positive, 594 (89%) HIV-exposed uninfected, and 52 (8%) HIV-unknown. The IYCF intervention increased mean length for age Z score by 0·26 (95% CI 0·09-0·43; p=0·003) and haemoglobin concentration by 2·9 g/L (95% CI 0·90-4·90; p=0·005). 165 (50%) of 329 children in the non-IYCF groups were stunted, compared with 136 (40%) of 336 in the IYCF groups (absolute difference 10%, 95% CI 2-17); and the prevalence of anaemia was also lower in the IYCF groups (45 [14%] of 319) than in the non-IYCF groups (24 [7%] of 329; absolute difference 7%, 95% CI 2-12). The WASH intervention had no effect on length or haemoglobin concentration. There were no trial-related adverse or serious adverse events.

INTERPRETATION

Since HIV-exposed children are particularly vulnerable to undernutrition and responded well to improved complementary feeding, IYCF interventions could have considerable benefits in areas of high antenatal HIV prevalence. However, elementary WASH interventions did not lead to improvements in growth.

FUNDING

Bill & Melinda Gates Foundation, UK Aid, Wellcome Trust, Swiss Development Cooperation, US National Institutes of Health, and UNICEF.

Dengue haemorrhagic fever: a job done via exosomes?

Dengue fever is one of those unique diseases where host immune responses largely determine the pathogenesis and its severity. Earlier studies have established the fact that dengue virus (DENV) infection causes haemorrhagic fever and shock syndrome, but it is not directly responsible for exhibiting these clinical symptoms. It is noteworthy that clinically, vascular leakage syndrome does not develop for several days after infection despite a robust innate immune response that elicits the production of proinflammatory and proangiogenic cytokines. The onset of hyperpermeability in severe cases of dengue disease takes place around the time of defervescence and after clearance of viraemia. Extracellular vesicles are known to carry biological information (mRNA, miRNA, transcription factors) from their cells of origin and have emerged as a significant vehicle for horizontal transfer of stress signals. In dengue virus infection, the relevance of exosomes can be instrumental since the majority of the immune responses in severe dengue involve heavy secretion and circulation of pro-inflammatory cytokines and chemokines. Here, we present an updated review which will address the unique and puzzling features of hyperpermeability associated with DENV infection with a special focus on the role of secreted extracellular vesicles.

Liver as a target of human immunodeficiency virus infection

Liver injury is a characteristic feature of human immunodeficiency virus (HIV) infection, which is the second most common cause of mortality in HIV-infected patients. Now it is recognized that liver plays a key role in HIV infection pathogenesis. Antiretroviral therapy (ART), which suppresses HIV infection in permissive immune cells, is less effective in hepatocytes, thereby making these cells a silent reservoir of HIV infection. In addition to direct hepatotoxic effects of HIV, certain ART treatment modalities provide hepatotoxic effects. The exact mechanisms of HIV-triggered chronic hepatitis progression are not elucidated, but the liver is adversely affected by HIV-infection and liver cells are prominently involved in HIV-elicited injury. These effects are potentiated by second hits like alcohol. Here, we will focus on the incidence of HIV, clinical evidence of HIV-related liver damage, interactions between HIV and liver cells and the role of alcohol and co-infection with hepatotropic viruses in liver inflammation and fibrosis progression.

I-FABP Is Higher in People With Chronic HIV Than Elite Controllers, Related to Sugar and Fatty Acid Intake and Inversely Related to Body Fat in People With HIV

Background

Intestinal fatty acid binding protein (I-FABP) has been shown to be a marker of intestinal damage among people living with HIV. We hypothesized that I-FABP would be increased in chronically HIV-infected patents more than elite controllers and would relate to specific nutrient intake and body composition.

Methods

In an observational study, serum I-FABP was measured by enzyme-linked immunosorbent assay. Anthropometric measurements, dual-energy x-ray absorptiometry, and single-slice abdominal computed tomography were obtained to assess body composition, as well as visceral and subcutaneous adipose tissue areas (VAT and SAT). Dietary intake was assessed using 4-day food records.

Results

One hundred forty-nine people with chronic HIV (65% male, 47 ± 7 years of age, 54.7% white, and 14 ± 6 years of known HIV), 10 elite controllers (60% male, 53 ± 8 years, 60% white, and 20 ± 7 years of known HIV), and 69 HIV-negative controls (59.4% male, 46 ± 7 years, and 52.2% white) were included in the analysis. I-FABP was significantly higher in HIV progressors relative to HIV-negative controls and elite controllers. In the chronic HIV group, I-FABP was positively associated with dietary intake of added sugar and with saturated fatty acids. I-FABP was inversely associated with body mass index, VAT, and SAT. I-FABP also correlated with MCP-1, CXCL10, sCD163, and lipopolysaccharide (LPS) among all participants.

Conclusions

I-FABP was increased among chronically HIV-infected patients to a greater degree than in elite controllers and was related to nutrient intake and body composition in HIV progressors. Future studies to investigate the role of intestinal damage on nutrient absorption are needed to elucidate the mechanisms of these relationships.

Trial Registration Identifier

NCT00455793.

Estradiol-regulated innate antiviral responses of human endometrial stromal fibroblasts

PROBLEM

The contribution of fibroblasts to innate immune protection of the human female reproductive tract (FRT) against viral pathogens is relatively unknown.

METHOD OF STUDY

Endometrial (EM), endocervical (Cx) and ectocervical (ECx) fibroblasts were isolated from hysterectomy patients and grown in vitro. Fibroblasts were treated with the viral mimic poly (I:C) in the presence or absence of the sex hormone estradiol (E2 ), with gene expression measured by real-time RT-PCR and protein secretion by ELISA.

RESULTS

Poly (I:C) induced the expression of the interferon-stimulated genes (ISG) MxA, OAS2 and APOBEC3G, and the cytokines MCP-1, IL-8, IL-6, CCL20, IFNβ and RANTES by fibroblasts from all three sites. ISG upregulation was dependent upon Type I IFN signaling. E2 inhibited the poly (I:C)-induced upregulation of MxA and OAS2 in EM fibroblasts, but not Cx or ECx fibroblasts. E2 upregulated SDF-1α by EM fibroblasts but had no effect on secretion of other cytokines either alone or in the presence of poly (I:C). Conditioned media (CM) from poly (I:C)-treated or E2 -treated fibroblasts significantly reduced HIV infection of CD4+ T cells.

CONCLUSION

Stromal fibroblasts represent a level of innate immune protection against viral pathogens in the FRT beyond that seen with epithelial cells and immune cells. Our findings indicate that fibroblasts FRT are selectively responsive to E2 , capable of initiating an antiviral response against viral pathogens and may play a role in preventing HIV infection of CD4+ T cells.

Common Cervicovaginal Microbial Supernatants Alter Cervical Epithelial Function: Mechanisms by Which Lactobacillus crispatus Contributes to Cervical Health

Cervicovaginal (CV) microbiota is associated with vaginal health and disease in non-pregnant women. Recent studies in pregnant women suggest that specific CV microbes are associated with preterm birth (PTB). While the associations between CV microbiota and adverse outcomes have been demonstrated, the mechanisms regulating the associations remain unclear. As the CV space contains an epithelial barrier, we postulate that CV microbiota can alter the epithelial barrier function. We investigated the biological, molecular, and epigenetic effects of Lactobacillus crispatus, Lactobacillus iners, and Gardnerella vaginalis on the cervical epithelial barrier function and determined whether L. crispatus mitigates the effects of lipopolysaccharide (LPS) and G. vaginalis on the cervical epithelial barrier as a possible mechanism by which CV microbiota mitigates disease risk. Ectocervical and endocervical cells treated with L. crispatus, L. iners, and G. vaginalis bacteria-free supernatants alone or combined were used to measure cell permeability, adherens junction proteins, inflammatory mediators, and miRNAs. Ectocervical and endocervical permeability increased after L. iners and G. vaginalis exposure. Soluble epithelial cadherin increased after exposure to L. iners but not G. vaginalis or L. crispatus. A Luminex cytokine/chemokine panel revealed increased proinflammatory mediators in all three bacteria-free supernatants with L. iners and G. vaginalis having more diverse inflammatory effects. L. iners and G. vaginalis altered the expression of cervical-, microbial-, and inflammatory-associated miRNAs. L. crispatus mitigated the LPS or G. vaginalis-induced disruption of the cervical epithelial barrier and reversed the G. vaginalis-mediated increase in miRNA expression. G. vaginalis colonization of the CV space of a pregnant C57/B6 mouse resulted in 100% PTB. These findings demonstrate that L. iners and G. vaginalis alter the cervical epithelial barrier by regulating adherens junction proteins, cervical immune responses, and miRNA expressions. These results provide evidence that L. crispatus confers protection to the cervical epithelial barrier by mitigating LPS- or G. vaginalis-induced miRNAs associated with cervical remodeling, inflammation, and PTB. This study provides further evidence that the CV microbiota plays a role in cervical function by altering the cervical epithelial barrier and initiating PTB. Thus, targeting the CV microbiota and/or its effects on the cervical epithelium may be a potential therapeutic strategy to prevent PTB.

Upsetting the Balance: When Viruses Manipulate Cell Polarity Control

The central importance of cell polarity control is emphasized by the frequency with which it is targeted by many diverse viruses. It is clear that in targeting key polarity control proteins, viruses affect not only host cell polarity, but also influence many cellular processes, including transcription, replication, and innate and acquired immunity. Examination of the interactions of different virus proteins with the cell and its polarity controls during the virus life cycles, and in virally-induced cell transformation shows ever more clearly how intimately all cellular processes are linked to the control of cell polarity.

Phenotypic and functional heterogeneity of peripheral γδ T cells in pulmonary TB and HIV patients in Addis Ababa, Ethiopia

Background

Previous studies reported HIV infection alters the distribution and function of γδ T cells and their subsets. γδ T phenotypes in healthy and diseased individuals has received little attention in Ethiopia. We conducted this study to analyze the distribution of γδ T cells, the subsets and levels of expression of activation (CD38), exhaustion or anergy (CD95, PD1), adhesion (N-CAM/CD56 and CD103), among HIV and TB infected patients.

Method

The distributions of total γδ T cells, Vδ1 and Vδ2 T cells subsets were analyzed in clinical samples collected from asymptomatic HIV, pulmonary TB patients and apparently healthy controls. Multicolor flow cytometry and IFN-γ ELISA were used to assess surface markers and functional responses of Vδ2 T cells to isopentenyl pyrophosphate stimulation, respectively.

Result

A total of 52 study participants were enrolled in this study, 22 HIV + TB-, 10 HIV-TB+ and 20 healthy controls. No significant differences were observed in the distribution of total γδ T cells and in the proportion of Vδ1 subsets in all study groups, though slightly higher proportions were observed in HIV + TB- patients for the latter, of borderline statistical significance (p = 0.07). However, the proportion of Vδ2 T cells, as well as the IFN-γ response to IPP stimulation, was significantly reduced in HIV + TB- patients compared to healthy controls (p < 0.002). Expression of the activation marker CD38 (p < 0.001) and adhesion marker CD103 (αEβ7) were significantly higher in the Vδ1 T cell subset among both HIV + TB- (p = 0.013) and HIV-TB+ (p = 0.006) patients compared to healthy controls. Similarly, exhaustion markers, CD95 and PD1, were significantly higher in these two T cell subsets among both HIV + TB- and HIV-TB+ patients (p < 0.01). Interestingly, we also observed an increased proportion of effector memory (CD45RA-CD27-) and effector cytotoxic (CD45RA + CD27-) Vδ2 T cell subsets in HIV negative pulmonary TB patients.

Conclusion

In sum, HIV infection was associated with an increase in Vδ1 and a decrease in the function and frequencies of Vδ2 T cells. Moreover, increased effector Vδ2 T cells were observed among HIV negative pulmonary TB patients suggesting a potential role of these T cells in the host response to TB.

Vaccine-Associated Maintenance of Epithelial Integrity Correlated With Protection Against Virus Entry

To identify the mechanisms by which human immunodeficiency virus type 1 (HIV-1) might penetrate the epithelial barrier during sexual transmission to women and the mechanisms of vaccine-associated protection against entry, we characterized early epithelial responses to vaginal inoculation of simian immunodeficiency virus strain mac251 (SIVmac251) in naive or SIVmac239Δnef-vaccinated rhesus macaques. Vaginal inoculation induced an early stress response in the cervicovaginal epithelium, which was associated with impaired epithelial integrity, damaged barrier function, and virus and bacterial translocation. In vaccinated animals, early stress responses were suppressed, and the maintenance of epithelial barrier integrity correlated with prevention of virus entry. These vaccine-protective effects were associated with a previously described mucosal system for locally producing and concentrating trimeric gp41 antibodies at the mucosal interface and with formation of SIV-specific immune complexes that block the stress responses via binding to the epithelial receptor FCGR2B and subsequent inhibitory signaling. Thus, blocking virus entry may be one protective mechanism by which locally concentrated non-neutralizing Ab might prevent HIV sexual transmission to women.

Intestinal damage precedes mucosal immune dysfunction in SIV infection

HIV and pathogenic SIV infection are characterized by mucosal dysfunction including epithelial barrier damage, loss of Th17 cells, neutrophil infiltration, and microbial translocation with accompanying inflammation. However, it is unclear how and when these contributing factors occur relative to one another. In order to determine whether any of these features initiates the cycle of damage, we longitudinally evaluated the kinetics of mucosal and systemic T-cell activation, microbial translocation, and Th17 cell and neutrophil frequencies following intrarectal SIV infection of rhesus macaques. We additionally assessed the colon proteome to elucidate molecular pathways altered early after infection. We demonstrate increased T-cell activation (HLA-DR+) beginning 3-14 days post-SIV challenge, reduced peripheral zonulin 3-14 days post-SIV, and evidence of microbial translocation 14 days post-SIV. The onset of mucosal dysfunction preceded peripheral and mucosal Th17 depletion, which occurred 14-28 days post-SIV, and gut neutrophil accumulation was not observed. Proteins involved in epithelial structure were downregulated 3 days post-SIV followed by an upregulation of immune proteins 14 days post-SIV. These data demonstrate that immune perturbations such as Th17 loss and neutrophil infiltration occur after alterations to epithelial structural protein pathways, suggesting that epithelial damage occurs prior to widespread immune dysfunction.

The relationship between sex hormones, the vaginal microbiome and immunity in HIV-1 susceptibility in women

The role of sex hormones in regulating immune responses in the female genital tract has been recognized for decades. More recently, it has become increasingly clear that sex hormones regulate susceptibility to sexually transmitted infections through direct and indirect mechanisms involving inflammation and immune responses. The reproductive cycle can influence simian/human immunodeficiency virus (SHIV) infections in primates and HIV-1 infection in ex vivo cervical tissues from women. Exogenous hormones, such as those found in hormonal contraceptives, have come under intense scrutiny because of the increased susceptibility to sexually transmitted infections seen in women using medroxyprogesterone acetate, a synthetic progestin-based contraceptive. Recent meta-analyses concluded that medroxyprogesterone acetate enhanced HIV-1 susceptibility in women by 40%. In contrast, estradiol-containing hormonal contraceptives were not associated with increased susceptibility and some studies reported a protective effect of estrogen on HIV/SIV infection, although the underlying mechanisms remain incompletely understood. Recent studies describe a key role for the vaginal microbiota in determining susceptibility to sexually transmitted infections, including HIV-1. While Lactobacillus spp.-dominated vaginal microbiota is associated with decreased susceptibility, complex microbiota, such as those seen in bacterial vaginosis, correlates with increased susceptibility to HIV-1. Interestingly, sex hormones are inherently linked to microbiota regulation in the vaginal tract. Estrogen has been postulated to play a key role in establishing a Lactobacillus-dominated microenvironment, whereas medroxyprogesterone acetate is linked to hypo-estrogenic effects. The aim of this Review is to contribute to a better understanding of the sex-hormone-microbiome-immunity axis, which can provide key information on the determinants of HIV-1 susceptibility in the female genital tract and, consequently, inform HIV-1 prevention strategies.

Lactobacillus crispatus accelerates re-epithelialization in vaginal epithelial cell line MS74

PROBLEM

The functions of vaginal lactobacilli in susceptibility to infectious diseases as regards epithelial barrier integrity and wound healing remain incompletely understood.

METHOD OF STUDY

Lactobacillus crispatus, one of the most common Lactobacillus species in the vagina and among the most protective against sexually transmitted infections, was cocultured with an immortalized human vaginal epithelial cell line (MS74), and a scratch assay was performed to evaluate re-epithelialization. The concentration of vascular endothelial growth factor A (VEGF) was measured using enzyme-linked immunosorbent assay (ELISA). An immunofluorescence assay was performed to locate the expression of VEGF and VEGF receptor (VEGFR) 1 and 2. The effects of the bacterial supernatant of L. crispatus were also evaluated.

RESULTS

Lactobacillus crispatus significantly accelerated re-epithelialization of MS74 cells, accompanied by an increase in VEGF concentration. In contrast, heat-killed L. crispatus did not show this effect. The bacterial supernatant of L. crispatus also induced re-epithelialization. The immunoreactivity of VEGF was higher at the scratched edge, whereas VEGFR1 and 2 stained site-independently. Recombinant VEGF induced cell migration in a dose-dependent manner. The bacterial supernatant of L. crispatus also significantly accelerated re-epithelialization in MS74 cells and increased the concentration of VEGF in the culture 24 hours after the scratch.

CONCLUSION

These results may enhance our knowledge of the importance of L. crispatus in the healing of damaged vaginal epithelium and protection against the consequent risk of pathogenic infections, such as human immunodeficiency virus (HIV), and improve our understanding of vaginal epithelial barrier integrity maintenance by this bacterium.

A high-resolution mass cytometry analysis reveals a delay of cytokines production after TLR4 or TLR7/8 engagements in HIV-1 infected humans

HIV infection is associated with chronic inflammation in both non-treated and treated patients. TLR-dependent mechanisms are strongly involved in the maintenance of this inflammation. Indeed, the residual replication of HIV, the potential viral co-infections, or the products issued from microbial translocation provide TLR ligands, which contribute to trigger innate immune responses. Maintaining this chronic inflammation leads to an exhaustion of the immune system. Therefore, the TLR-dependent responses could be altered in HIV-infected patients. To investigate this hypothesis, we performed high-resolution phenotyping using a mass cytometry panel of 34 cell markers. Whole blood cells from healthy, non-treated HIV-infected and ART-treated HIV-infected subjects were stimulated with LPS, R848 or Poly(I:C). We observed the immune responses induced in T-cells, B-cells, polymorphonuclear cells, NK cells, basophils, monocytes and dendritic cells. We observed that, for either LPS or R848 stimulations, the production of cytokines in monocytes and conventional dendritic cells was delayed in treated or non-treated HIV-infected patients, compared to healthy individuals. These results suggest that leukocytes from chronic HIV-infected patients are slower to respond following the sensing of pathogens and danger signals, which may be an important feature of HIV infection.

Hormonal influence on HIV-1 transmission in the female genital tract: New insights from systems biology

Although anti-retroviral treatments have significantly slowed down the spread of the HIV-1 pandemic, approximately 2 million new infections occur every year. The majority of new infections are in sub-Saharan Africa where rates of infection are much higher in women than men. Young women are disproportionately affected and have higher susceptibility to HIV-1. The complex interactions between HIV-1 and the female genital tract (FGT) and the mechanisms regulating susceptibility in women remain incompletely understood. In this review, we focus on the current understanding of the acute events that occur in the FGT following HIV-1 exposure with a particular focus on the effect of endogenous and exogenous sex hormones on HIV-1 susceptibility. We highlight the contribution of the recent transcriptomic and proteomic studies in providing new insights.

Inflammation and intestinal leakiness in older HIV+ individuals with fish oil treatment

Fish oil is a natural product that has shown efficacy for managing inflammatory conditions with few side effects. There is emerging evidence that crosstalks between gut epithelial cells and immune cells contribute to chronic infectious diseases. HIV-infected (HIV+) older adults show age-related co-morbidities at a younger age than their uninfected counterparts. Persistent inflammation related to the chronic viral infection and its sequelae is thought to contribute to this disparity. However, little is known about whether fish oil reduces intestinal inflammation in HIV + patients. We measure inflammation and gut barrier function in HIV + older adults (median age = 52, N = 33), following 12 weeks of fish oil supplementation (a total daily dose of 1.6 g of omega-3 fatty acids). We showed a reduction in inflammation and gut permeability as measured by CD14, inflammatory cytokines, lipopolysaccharide, and lipopolysaccharide binding protein. The results indicate that older HIV + adults may benefit from a diet supplemented with the omega-3 fatty acids found in fish oil.

Ex vivo HIV entry into blood CD4+ T cells does not predict heterosexual HIV acquisition in women

Background

A blood-based assay that could quantify HIV susceptibility would be very valuable for HIV prevention research. Previously, we developed and validated an ex vivo, flow-based, HIV entry assay to assess genital HIV susceptibility in endocervical CD4+ T cells.

Methods

Here we assessed whether this tool could be used to predict HIV risk using blood-derived CD4+ T cells in a rigorously-blinded, nested case-control study using blood samples collected from high-risk, HIV-uninfected South African women enrolled in the CAPRISA 004 clinical trial. Cases, subsequently acquiring HIV were sampled prior to HIV infection and compared with controls, who remained HIV-uninfected. The primary endpoint was ex vivo entry of a CCR5-tropic HIV founder virus into blood CD4+ T cells. Secondary endpoints included HIV entry into CD4+ central (T_CM) and effector (T_EM) memory T cells, and into CD4+ T cell subsets expressing CCR5, CD69, CCR6, α4β1 or α4β7.

Results

Compared to bulk CD4+ T cells (4.9% virus entry), CD4+ T cells expressing CCR5, CCR6 or α4β1 and T_EM were highly susceptible (15.5%, 8.8%, 8.2% and 10.8% entry, respectively, all p<0.0001), while T_CM, CD69+ or α4β7+ CD4+ cells were moderately susceptible (6.4%, 6.0% and 5.8% respectively, p ≤ 0.003). While the proportion of the aforementioned highly susceptible cells correlated with overall virus entry into CD4+ T cells within an individual (r = 0.68, 0.47, 0.67, and 0.60 respectively, p<0.0001), blood virus entry did not predict subsequent mucosal HIV acquisition after controlling for sexual behaviour and condom use (OR 0.92, 95% CI 0.77–1.11, p = 0.40).

Conclusions

Although virus entry identified several previously known highly susceptible cellular HIV targets, blood HIV entry did not predict subsequent heterosexual HIV acquisition. Assessment of mucosal HIV susceptibility may require sampling at the site of HIV exposure.

Microbial translocation: translating simian immunodeficiency virus to HIV

PURPOSE OF REVIEW

The article describes recent advances in understanding the causes and consequences of microbial translocation in HIV and simian immunodeficiency virus infections.

RECENT FINDINGS

Persistent microbial translocation contributes to aberrant immune activation in immunodeficiency lentiviral infections and thereby, pathogenesis and mortality. Efforts to delineate the circumstances surrounding translocation have benefited from use of simian immunodeficiency virus-infected nonhuman primates and highlight the overwhelming immunologic diversion caused by translocating microbes. The use of therapeutics aimed at reducing microbial translocation show promise and will benefit from continued research into the mechanisms that promote systemic microbial dissemination in treated and untreated infections.

SUMMARY

Insights into the source and identity of translocating microbes in lentiviral infections continue to enhance the development of adjunct therapeutics.

Apoptosis of enterocytes and nitration of junctional complex proteins promote alcohol-induced gut leakiness and liver injury

BACKGROUND & AIMS

Binge alcohol exposure causes gut leakiness, contributing to increased endotoxemia and inflammatory liver injury, although the molecular mechanisms are still elusive. This study was aimed at investigating the roles of apoptosis of enterocytes and nitration followed by degradation of intestinal tight junction (TJ) and adherens junction (AJ) proteins in binge alcohol-induced gut leakiness.

METHODS

The levels of intestinal (ileum) junctional complex proteins, oxidative stress markers and apoptosis-related proteins in rodents, T84 colonic cells and autopsied human ileums were determined by immunoblot, immunoprecipitation, immunofluorescence, and mass-spectral analyses.

RESULTS

Binge alcohol exposure caused apoptosis of gut enterocytes with elevated serum endotoxin and liver injury. The levels of intestinal CYP2E1, iNOS, nitrated proteins and apoptosis-related marker proteins were significantly elevated in binge alcohol-exposed rodents. Differential, quantitative mass-spectral analyses of the TJ-enriched fractions of intestinal epithelial layers revealed that several TJ, AJ and desmosome proteins were decreased in binge alcohol-exposed rats compared to controls. Consistently, the levels of TJ proteins (claudin-1, claudin-4, occludin and zonula occludens-1), AJ proteins (β-catenin and E-cadherin) and desmosome plakoglobin were very low in binge alcohol-exposed rats, wild-type mice, and autopsied human ileums but not in Cyp2e1-null mice. Additionally, pretreatment with specific inhibitors of CYP2E1 and iNOS prevented disorganization and/or degradation of TJ proteins in alcohol-exposed T84 colonic cells. Furthermore, immunoprecipitation followed by immunoblot confirmed that intestinal TJ and AJ proteins were nitrated and degraded via ubiquitin-dependent proteolysis, resulting in their decreased levels.

CONCLUSIONS

These results demonstrated for the first time the critical roles of CYP2E1, apoptosis of enterocytes, and nitration followed by ubiquitin-dependent proteolytic degradation of the junctional complex proteins, in promoting binge alcohol-induced gut leakiness and endotoxemia, contributing to inflammatory liver disease.

LAY SUMMARY

Binge alcohol exposure causes gut leakiness, contributing to increased endotoxemia and inflammatory liver injury. Our results demonstrated for the first time the critical roles of apoptosis of enterocytes and nitration followed by ubiquitin-dependent proteolytic degradation of the junctional complex proteins in promoting this gut leakiness and endotoxemia. These results provide insight into the molecular mechanisms of alcohol-induced inflammatory liver disease.

Impact of chronic sexual abuse and depression on inflammation and wound healing in the female reproductive tract of HIV-uninfected and HIV-infected women

Sexual violence is associated with increased risk of HIV acquisition/transmission in women. Forced sex can result in physical trauma to the reproductive tract as well as severe psychological distress. However, immuno-biological mechanisms linking sexual violence and HIV susceptibility are incompletely understood. Using the Women’s Interagency HIV Study repository, a total of 77 women were selected to form 4 groups, stratified by HIV serostatus, in the following categories: 1) no sexual abuse history and low depressive symptom score (below clinically significant cut-off, scores <16) (Control); 2) no sexual abuse history but high depressive symptom score, ≥16 (Depression); 3) chronic sexual abuse exposure and low depressive symptom score (Abuse); 4) chronic sexual abuse exposure and high depressive symptom score (Abuse+Depression). Inflammation-associated cytokines/chemokines/proteases (TNF-α, IL-6, IL-1α, IL-1β, TGF-β MIP-3α, IP-10, MCP-1, Cathepsin B), anti-inflammatory/anti-HIV mediators (Secretory leukocyte protease inhibitor (SLPI), Elafin, beta defensin 2 (HBD2), alpha defensins (HNP 1–3), Thrombospondin (TSP-1), Serpin A1, A5, Cystatin A, B), and wound-healing mediators (Gro-α, VEGF, PDGF, EGF, FGF, IGF), were measured in cervical-vaginal lavage (CVL) using ELISA. Linear regression was used to model association of biomarkers with depression and abuse as predictor variables; the interaction between depression and abuse was also tested. Anti-HIV activity in CVL was tested using TZM-bl indicator cell line. In HIV-uninfected women, median levels of IL-6 (p = 0.04), IL-1α (p<0.01), TGF-β (p = 0.01), IP-10 (p = <0.01), PDGF (p<0.01) and FGF (p<0.01), differed significantly between groups. Specifically, an association was found between chronic sexual abuse and increased IL-1α (p<0.01), MIP-3α (p = 0.04), IP-10 (p<0.01), Serpin B1 (p = 0.01), FGF (p = 0.04) and decreased TGF-β (p<0.01), MCP-1 (p = 0.02), PDGF (p<0.01). Further, there was evidence of significant interactions between chronic sexual abuse and current depression for IL-1α, IP-10, Serpin A1, Cystatin B, and FGF. In HIV-infected women, median levels of TNF-α (p<0.01), IL-6 (p = 0.05), MIP-3α (p<0.01), and MCP-1 (p = 0.01), differed significantly between groups. Specifically, an association was found between chronic sexual abuse and increased MCP-1 (p = 0.03), Gro-α (p = 0.01) and decreased TNF-α (p<0.01), IL-1α (p = 0.02), MIP-3α (p<0.01) and Cathepsin B (p = 0.03). Current depressive symptoms were associated with significantly decreased MIP-3α (p<0.01). There was evidence of significant interactions between chronic sexual abuse and current depression for MCP-1 and FGF. No significant differences were observed in anti-HIV activity among all eight groups. Heat-map analyses revealed distinct immune network patterns, particularly in the Abuse groups for both HIV-infected and uninfected women. Our data indicates a complex relationship between chronic sexual abuse exposure, depressive symptoms, and FRT immune mediators that are also affected by HIV status. Association of chronic sexual abuse with increase in inflammation-associated cytokine/chemokine expression, along with impaired wound-healing associated growth-factors can create a microenvironment that can facilitate HIV infection. Evaluation of longitudinal changes in exposures and biomarkers are needed to untangle the immuno-biological mechanisms that may put women who endure life-long sexual abuse at increased risk for HIV.

Understanding mucosal and microbial functionality of the female reproductive tract by metaproteomics: Implications for HIV transmission

The mucosal surface of the female genital tract contains physiological, immunological, and microbial components that collectively comprise a functioning "mucosal system" that is critical for reproductive health. Alterations or imbalances to any of these components can have significant consequences for susceptibility to sexually transmitted infections, such as HIV. In recent years the advent of advanced systems biology technologies, such as metaproteomics, has provided new toolsets to studying mucosal systems. Studies have linked an altered mucosal proteome to many HIV risk factors including mucosal inflammation, bacterial vaginosis, hormonal contraceptives, and reduced efficacy of antiretroviral drugs for HIV prevention. Herein we will discuss how metaproteomics has been used to study mucosal system components, including epithelial barriers, inflammation, and the microbiome, with a focus on what alterations may contribute to increased HIV transmission risk in women.

Assessment of microbiota:host interactions at the vaginal mucosa interface

There is increasing appreciation of the role that vaginal microbiota play in health and disease throughout a woman's lifespan. This has been driven partly by molecular techniques that enable detailed identification and characterisation of microbial community structures. However, these methods do not enable assessment of the biochemical and immunological interactions between host and vaginal microbiota involved in pathophysiology. This review examines our current knowledge of the relationships that exist between vaginal microbiota and the host at the level of the vaginal mucosal interface. We also consider methodological approaches to microbiomic, immunologic and metabolic profiling that permit assessment of these interactions. Integration of information derived from these platforms brings the potential for biomarker discovery, disease risk stratification and improved understanding of the mechanisms regulating vaginal microbial community dynamics in health and disease.

Natural Immunity to HIV: A Template for Vaccine Strategies

Africa accounts for the majority of global human immunodeficiency virus (HIV) infections, most of which affect women through heterosexual intercourse. Currently, there is no cure for HIV and the development of vaccines and microbicides remains the best solution to eradicate the pandemic. We and others have identified HIV highly-exposed seronegative (HESN) individuals among African female commercial sex workers (CSWs). Analyses of genital samples from HESNs have demonstrated potent innate and anti-inflammatory conditions, HIV-specific CD4⁺ and CD8⁺ T-cells as well as immunoglobulins (Igs), and increased regulatory cell populations, all of which support a delicate balance between strength and control against HIV intrusion. Moreover, we have recently shown that frequencies of innate marginal zone (MZ) B-cells are decreased in the blood of HESNs when compared to HIV-uninfected non-CSW women, suggesting their recruitment to peripheral sites. This coincides with the fact that levels of B lymphocyte stimulator (BLyS/BAFF), known to shape the MZ pool and whose overexpression leads to MZ deregulation in HIV-infected progressors, are significantly lower in the blood of HESNs when compared to both HIV-infected CSWs and HIV-uninfected non-CSW women. Interestingly, MZ B-cells can bind HIV gp120 and produce specific IgG and IgA, and have a propensity for B regulatory potential, which could help both the fight against HIV and maintenance of low inflammatory conditions in HESNs. HESN individuals provide an exceptional opportunity to identify important clues for the development of protective devices, and efforts should aim at soliciting immune responses observed in the context of their natural immunity to HIV.

HIV induces production of IL-18 from intestinal epithelial cells that increases intestinal permeability and microbial translocation

Interleukin-18 (IL-18) is a pleiotropic cytokine of the IL-1 family with multiple context dependent functions. We and others have shown that HIV infection is accompanied by increased circulating levels of IL-18 along with decreased levels of its antagonist, Interleukin-18 Binding Protein (IL-18BP). The infection is also accompanied by intestinal inflammation and decreased intestinal integrity as measured by intestinal permeability, regeneration and repair. However, little is known concerning the relation between high level of IL-18 associated with the viral infection and intestinal permeability. Here we demonstrate that HIV treatment increases production of IL-18 and decreases that of IL-18BP production in human intestinal epithelial cell (IEC) lines. IL-18 causes apoptosis of the IEC by activating caspase-1 and caspase-3. It induces epithelial barrier hyperpermeability by decreasing and disrupting both tight and adherens junction proteins, occludin, claudin 2 and beta-catenin. Disorganization of F-actin was also observed in the IEC that were exposed to the cytokine. Moreover IL-18 decreases transepithelial electrical resistance (TEER) in Caco-2 and increases permeability in HT29 monolayers. The cells' treatment with IL-18 causes an increase in the expression of phosphorylated myosin II regulatory light-chain (p-MLC) and myosin light-chain kinase (MLCK), and a decrease in phosphorylated Signal Transducer and Activator of Transcription (p-STAT)-5. This increase in p-MLC is suppressed by a Rho-kinase (ROCK)-specific inhibitor. Interestingly, the levels of the cytokine correlate with those of LPS in the circulation in three different categories of HIV infected patients (HAART-naïve and HAART-treated HIV-infected individuals, and Elite controls) as well as in healthy controls. Collectively, these results suggest that the HIV-induced IL-18 plays a role in increased intestinal permeability and microbial translocation observed in HIV-infected individuals.

HIV-1 Tat-induced diarrhea is improved by the PPARalpha agonist, palmitoylethanolamide, by suppressing the activation of enteric glia

Background

Diarrhea is a severe complication in HIV-1-infected patients with Trans-activator of transcription (HIV-1 Tat) protein being recognized as a major underlying cause. Beside its direct enterotoxic effects, Tat protein has been recently shown to affect enteric glial cell (EGC) activity. EGCs regulate intestinal inflammatory responses by secreting pro-inflammatory molecules; nonetheless, they might also release immune-regulatory factors, as palmytoilethanolamide (PEA), which exerts anti-inflammatory effects by activating PPARα receptors. We aimed at clarifying whether EGCs are involved in HIV-1 Tat-induced diarrhea and if PEA exerts antidiarrheal activity.

Methods

Diarrhea was induced by intracolonic administration of HIV-1 Tat protein in rats at day 1. PEA alone or in the presence of peroxisome proliferator-activated receptor (PPAR) antagonists was given intraperitoneally from day 2 to day 7. S100B, iNOS, NF-kappaB, TLR4 and GFAP expression were evaluated in submucosal plexi, while S100B and NO levels were measured in EGC submucosal plexi lysates, respectively. To verify whether PEA effects were PPARα-mediated, PPARα^−/− mice were also used. After 7 days from diarrhea induction, endogenous PEA levels were measured in submucosal plexi homogenates deriving from rats and PPARα^−/− mice.

Results

HIV-1 Tat protein induced rapid onset diarrhea alongside with a significant activation of EGCs. Tat administration significantly increased all hallmarks of neuroinflammation by triggering TLR4 and NF-kappaB activation and S100B and iNOS expression. Endogenous PEA levels were increased following HIV-1 Tat exposure in both wildtype and knockout animals. In PPARα^−/− mice, PEA displayed no effects. In wildtype rats, PEA, via PPARα-dependent mechanism, resulted in a significant antidiarrheal activity in parallel with marked reduction of EGC-sustained neuroinflammation.

Conclusions

EGCs mediate HIV-1 Tat-induced diarrhea by sustaining the intestinal neuroinflammatory response. These effects are regulated by PEA through a selective PPARα-dependent mechanism. PEA might be considered as an adjuvant therapy in HIV-1-induced diarrhea.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1126-4) contains supplementary material, which is available to authorized users.

Interferon-β induced in female genital epithelium by HIV-1 glycoprotein 120 via Toll-like-receptor 2 pathway acts to protect the mucosal barrier

More than 40% of HIV infections occur via female reproductive tract (FRT) through heterosexual transmission. Epithelial cells that line the female genital mucosa are the first line of defense against HIV-1 and other sexually transmitted pathogens. These sentient cells recognize and respond to external stimuli by induction of a range of carefully balanced innate immune responses. Previously, we have shown that in response to HIV-1 gp120, the genital epithelial cells (GECs) from upper reproductive tract induce an inflammatory response that may facilitate HIV-1 translocation and infection. In this study, we report that the endometrial and endocervical GECs simultaneously induce biologically active interferon-β (IFNβ) antiviral responses following exposure to HIV-1 that act to protect the epithelial tight junction barrier. The innate antiviral response was directly induced by HIV-1 envelope glycoprotein gp120 and addition of gp120 neutralizing antibody inhibited IFNβ production. Interferon-β was induced by gp120 in upper GECs through Toll-like receptor 2 signaling and required presence of heparan sulfate on epithelial cell surface. The induction of IFNβ was dependent upon activation of transcription factor IRF3 (interferon regulatory factor 3). The IFNβ was biologically active, had a protective effect on epithelial tight junction barrier and was able to inhibit HIV-1 infection in TZM-bl indicator cells and HIV-1 replication in T cells. This is the first report that recognition of HIV-1 by upper GECs leads to induction of innate antiviral pathways. This could explain the overall low infectivity of HIV-1 in the FRT and could be exploited for HIV-1 prophylaxis.

Large-Scale Arrayed Analysis of Protein Degradation Reveals Cellular Targets for HIV-1 Vpu

Accessory proteins of lentiviruses, such as HIV-1, target cellular restriction factors to enhance viral replication. Systematic analyses of proteins that are targeted for degradation by HIV-1 accessory proteins may provide a better understanding of viral immune evasion strategies. Here, we describe a high-throughput platform developed to study cellular protein stability in a highly parallelized matrix format. We used this approach to identify cellular targets of the HIV-1 accessory protein Vpu through arrayed coexpression with 433 interferon-stimulated genes, followed by differential fluorescent labeling and automated image analysis. Among the previously unreported Vpu targets identified by this approach, we find that the E2 ligase mediating ISG15 conjugation, UBE2L6, and the transmembrane protein PLP2 are targeted by Vpu during HIV-1 infection to facilitate late-stage replication. This study provides a framework for the systematic and high-throughput evaluation of protein stability and establishes a more comprehensive portrait of cellular Vpu targets.

Transcriptional profiling of primary endometrial epithelial cells following acute HIV-1 exposure reveals gene signatures related to innate immunity

PROBLEM

Genital epithelial cells (GECs) line the mucosal surface of the female genital tract (FGT) and are the first cells that interface with both commensal microbiota and sexually transmitted pathogens. Despite the protective barrier formed by GECs, the FGT is a major site of HIV-1 infection. This highlights the importance of studying the interaction of HIV-1 and GECs.

METHOD OF STUDY

Using microarray analysis, we characterized the transcriptional profile of primary endometrial GECs grown in the presence or absence of physiological levels of E2 (10^-9  mol/L) or P4 (10^-7  mol/L) following acute exposure to HIV-1 for 6 hours.

RESULTS

Acute exposure of primary endometrial GECs to HIV-1 resulted in the expression of genes related to inflammation, plasminogen activation, adhesion and diapedesis and interferon response. Interestingly, exposure to HIV-1 in the presence of E2 and P4 resulted in differential transcriptional profiles, suggesting that the response of primary endometrial GECs to HIV-1 exposure is modulated by female sex hormones.

CONCLUSION

The gene expression signature of endometrial GECs indicates that the response of these cells may be key to determining host susceptibility to HIV-1 and that sex hormones modulate these interactions. This study allows us to explore possible mechanisms that explain the hormone-mediated fluctuation of HIV-1 susceptibility in women.

Bronchiectasis and other chronic lung diseases in adolescents living with HIV

PURPOSE OF REVIEW

The incidence of pulmonary infections has declined dramatically with improved access to antiretroviral therapy (ART) and cotrimoxazole prophylaxis, but chronic lung disease (CLD) is an increasingly recognized but poorly understood complication in adolescents with perinatally acquired HIV.

RECENT FINDINGS

There is a high prevalence of chronic respiratory symptoms, abnormal spirometry and chest radiographic abnormalities among HIV-infected adolescents in sub-Saharan Africa, wherein 90% of the world's HIV-infected children live. The incidence of lymphocytic interstitial pneumonitis, the most common cause of CLD in the pre-ART era, has declined with increased ART access. Small airways disease, particularly constrictive obliterative bronchiolitis and bronchiectasis, are emerging as leading causes of CLD among HIV-infected adolescents in low-income and middle-income countries. Asthma may be more common in high-income settings. Likely risk factors for CLD include recurrent pulmonary infections, air pollution, HIV-related immune dysfunction, and untreated HIV infection, particularly during critical stages of lung development.

SUMMARY

Globally, the importance of HIV-associated CLD as a cause of morbidity and mortality is increasing, especially as survival has improved dramatically with ART and growing numbers of children living with HIV enter adolescence. Further research is urgently needed to elucidate the natural history and pathogenesis of CLD, and to determine optimal screening, diagnostic and treatment strategies.

Colon dysregulation in methamphetamine self-administering HIV-1 transgenic rats

The integrity and function of the gut is impaired in HIV-infected individuals, and gut pathogenesis may play a role in several HIV-associated disorders. Methamphetamine is a popular illicit drug abused by HIV-infected individuals. However, the effect of methamphetamine on the gut and its potential to exacerbate HIV-associated gut pathology is not known. To shed light on this scenario, we evaluated colon barrier pathology in a rat model of the human comorbid condition. Intestinal barrier integrity and permeability were assessed in drug-naïve Fischer 344 HIV-1 transgenic (Tg) and non-Tg rats, and in Tg and non-Tg rats instrumented with jugular cannulae trained to self-administer methamphetamine or serving as saline-yoked controls. Intestinal permeability was determined by measuring the urine content of orally gavaged sugars. Intestinal barrier integrity was evaluated by immunoblotting or immunofluorescence of colon claudin-1 and zonula occludens-1 (ZO-1), two major tight junction proteins that regulate gut epithelial paracellular permeability. Both non-Tg and Tg rats self-administered moderate amounts of methamphetamine. These amounts were sufficient to increase colon permeability, reduce protein level of claudin-1, and reduce claudin-1 and ZO-1 immunofluorescence in Tg rats relative to non-Tg rats. Methamphetamine decreased tight junction immunofluorescence in non-Tg rats, with a similar, but non-significant trend observed in Tg rats. However, the effect of methamphetamine on tight junction proteins was subthreshold to gut leakiness. These findings reveal that both HIV-1 proteins and methamphetamine alter colon barrier integrity, and indicate that the gut may be a pathogenic site for these insults.

Drug Use is Associated with Anti-CD4 IgG-mediated CD4+ T Cell Death and Poor CD4+ T Cell Recovery in Viral-suppressive HIV-infected Individuals Under Antiretroviral Therapy

BACKGROUND

The role and mechanism of drug use or abuse in Antiretroviral Therapy (ART)-treated HIV disease are not completely known.

METHODS

To investigate the impact of drug use on HIV pathogenesis without confounding by HIV replication and ART adherence, we first analyzed the data from our clinical database in 103 HIV+ subjects with viral-suppressed ART treatment by a multiple regression test.

RESULTS

We found that HIV+ drug users had lower CD4+ T cell counts but higher CD8+ T cell counts compared to HIV+ non-drug users, and both drug use and nadir CD4+ T cell counts was independently associated with CD4+ T cell recovery after controlling for sex and age. Next, we enrolled individuals from four study groups, HIV-negative and HIV+ subjects without any substance use, HIV-negative and HIV+ subjects with current illicit drug use (either non-injection cocaine or cannabis). All HIV+ subjects were viral-suppressed with ART treatment (≥ 2 years). Notably, HIV+ drug users had increased plasma anti-CD4 IgG levels compared to the other three study groups which were inversely correlated with decreased CD4+ T cell counts only in HIV+ drug users. There was a significant increase in CD4+ T cell recovery following ART in HIV+ non-drug users but not in HIV+ drug users. Anti-CD4 IgGs purified from plasma of HIV+ drug users induced CD4+ T cell death in vitro through Antibody-Dependent Cytotoxicity (ADCC).

CONCLUSION

These results suggest that drug use prevents immune reconstitution in HIV-infected individuals despite long-term ART treatment and viral suppression.

HIV-2 infection is associated with preserved GALT homeostasis and epithelial integrity despite ongoing mucosal viral replication

The mechanisms that enable preservation of gut mucosal integrity during persistent viral replication and inherent inflammation remain unclear. Here, we investigated, for the first time, gut homeostasis in HIV-2 infection, a naturally occurring form of attenuated HIV disease. We found viral replication in both sigmoid and ileum of asymptomatic HIV-2+ patients (range: 240-851 circulating CD4+T-cells per μl) despite their undetectable viremia, accompanied by interferon-γ-producing CD8 T-cell expansion, irrespective of antiretroviral treatment. Nevertheless, there was no CD4 T-cell depletion, and Foxp3+ and IL-17- or IL-22-producing CD4 T-cell numbers were unaffected. Moreover, IL-22-producing innate lymphoid cells and IL-22-induced antimicrobial peptides and mucins were maintained. In agreement, the epithelium histology was preserved, including tight junction protein zonula occludens (ZO-1) levels. Furthermore, in vitro infection of colon epithelia with primary isolates revealed no HIV-2 impact on ZO-1 expression. Notably, sigmoid transcriptional levels of CCL20 and CCL28 were significantly increased, in direct correlation with GM-CSF, indicating a local response able to enhance CD4 T-cell recruitment. In conclusion, maintenance of mucosal integrity in HIV-2 infection was associated with T-cell recruitment responses, potentially counteracting CD4 T-cell depletion due to HIV-2 replication. These data have unique implications for the design of therapies targeting gut homeostasis in HIV-1 infection and other chronic inflammatory settings.

Residual Immune Activation and Latency

The introduction of combination antiretroviral therapy (cART) in the 1990s has dramatically changed the course of HIV infection, decreasing the risk for both AIDS- and non-AIDS-related events. Cancers, cardiovascular disease (CVD), liver and kidney disease, neurological disorders and frailty have become of great importance lately in the clinical management as they represent the principal cause of death in people living with HIV who receive cART (Kirk et al. in Clin Infect Dis 45(1):103-10, 2007; Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006; Ances et al. J Infect Dis 201(3):336-340, 2010; Desquilbet et al. J Gerontol A Biol Sci Med Sci 62(11):1279-1286, 2007; Lifson et al. HIV Clin Trials 9(3):177-185, 2008). Despite the undeniable achievements of cART, we are now faced with its limitations: a considerable proportion of individuals, referred as to immunological non-responders, fails to reconstitute the immune system despite optimal treatment and viral suppression (Kelley et al. Clin Infect Dis 48(6):787-794, 2009; Robbins et al. Clin Infect Dis 48(3):350-361, 2009) and remains at high risk for opportunistic infections and non-AIDS-related events (Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006). Moreover, the generalized state of immune activation and inflammation, linked to serious non-AIDS events, persists despite successful HIV suppression with cART. Finally, the current strategies have so far failed to eradicate the virus, and inflammation appears a driving force in viral persistence. In the light of all this, it is of fundamental importance to investigate the pathophysiological processes that link incomplete immune recovery, immune activation and HIV persistence to design targeted therapies that could impact on the three.

The Effect of Commonly Used Excipients on the Epithelial Integrity of Human Cervicovaginal Tissue

Pharmaceutical excipients are widely used in vaginal drug products. The epithelial integrity of the cervicovaginal tissue is important for HIV-1 prevention. However, the effects of excipients on cervicovaginal epithelium remain unknown. This study aims at assessing the effects of vaginal product excipients on the integrity of human cervicovaginal epithelium and on a lead HIV prevention antiretroviral drug, tenofovir (TFV). In the current study, nine excipients commonly used in vaginal formulations were incubated for 6 h with excised human ectocervical tissue. The effects of the excipients were examined by measuring the transepithelial electrical resistance (TEER), epithelial morphology, paracellular/transcellular permeability, and cell viability. The efficacy of TFV for preventing HIV-1 infection in the ex vivo cultured ectocervix was also tested. We found that disodium ethyl-enediaminetetraacetate (EDTA), sorbic acid, and benzoic acid had no effect on the tissue TEER. Butylated hydroxyanisole, glycerin, propylene glycol, methylparaben, and propylparaben slightly to moderately decreased tissue TEER, whereas citric acid significantly decreased the TEER in a time-dependent manner. Tissue morphology observed post-exposure strongly correlated with TEER data; however, a less strong correlation was observed between paracellular permeability and TEER data after exposure to different excipients. In addition, treatment with EDTA, methylparaben, and propylene glycol at tested levels had no effect on the efficacy of TFV in preventing tissue HIV-1 infection. In conclusion, the combined measurements of TEER, morphology, permeability, and viability using human cervicovaginal tissue represent a clinically relevant platform for safety evaluation of excipients and formulated products for HIV-1 prevention.