Contribution of the Microbiota to Intestinal Homeostasis and its Role in the Pathogenesis of HIV-1 Infection

Bovine Colostrum in Increased Intestinal Permeability in Healthy Athletes and Patients: A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Increasing intestinal permeability causes chronic inflammation, which is one of the etiological factors of many diseases that presently constitute global challenges.

AIMS

Considering the importance of developing therapies to eliminate the increased intestinal permeability, in this systematic review and meta-analysis, we analyze the impact of bovine colostrum (BC) on the gut barrier and its permeability.

METHODS

Online databases, including PubMed, ISI Web of Science, and Scopus, were searched to find pertinent articles up to March 2022. Weighted mean difference (WMD) and 95% confidence intervals (CI) were considered as effect sizes. The random-effects model was used to pool the study results.

RESULTS

A total of ten articles were included in the meta-analysis. The pooled effect revealed a significant reduction in the 5-h urinary lactulose/rhamnose ratio after BC consumption [mean difference (MD): -0.24; 95% CI -0.43 to -0.04; I2 = 99%] and urinary lactulose/mannitol ratio (MD: -0.01; 95% CI -0.02 to -0.001; I2 = 29.8%). No differences were observed in the plasma intestinal fatty acid-binding protein (I-FABP) between BC and control groups (MD: 2.30; 95% CI -293.9 to 298.5; I2 = 92%).

CONCLUSIONS

BC supplementation significantly reduced intestinal permeability; however, to confirm the results, more randomized clinical trials considering different quality, dose, and duration are needed.

Traditional Chinese medicine (Xielikang) reduces diarrhea symptoms in acquired immune deficiency syndrome (AIDS) patients by regulating the intestinal microbiota

Diarrheal acquired immune deficiency syndrome (AIDS) seriously affects the quality of life of patients. In this study, we analyzed the differences in the intestinal microbiota among healthy individuals, AIDS patients without diarrhea and AIDS patients with diarrhea through high-throughput sequencing. The microbial diversity in the intestines of patients in the AIDS diarrhea group was significantly increased, and after treatment with Xielikang, the intestinal microbial diversity returned to the baseline level. At the phylum level, compared those in to the healthy (ZC) and AIDS non diarrhea (FN) groups, the relative abundances of Bacteroidetes and Verrucomirobia in the AIDS diarrhea (FA) group before treatment were significantly increased, while the relative abundance of Firmicutes was significantly decreased. Similarly, compared with those in the FA group, the relative abundances of Bacteroidea and Firmicutes in the AIDS diarrhea (FB) group after treatment were significantly increased, while the relative abundance of Firmicutes was significantly decreased after treatment. Additionally, there was no significant difference between the ZC and FN groups. At the genus level, compared with those in the ZC group, the relative abundance of Prevotella and Escherichia_Shigella in the FA group was significantly increased, while the relative abundances of Megamonas and Bifidobacterium was significantly decreased compared to that in the ZC group. After treatment with Xielikang, the relative abundance of Prevotella and Escherichia_Shigella in the FB group were significantly decreased, while the relative abundances of Megamonas and Bifidobacteria were significantly increased than those in the FA group; moreover, there was no significant difference between the ZC and FN groups. The functional prediction results showed that the ketodeoxyoctonate (Kdo) transfer to lipid IVA III and the superpathway of N-acetylglucosamine pathways in the AIDS diarrhea group were significantly altered. The correlation analysis results showed that Dorea was positively correlated with inflammatory factors, while Streptococcus and Lactobacillus were negatively correlated with inflammatory factors. The composition and function of the intestinal microbiota changed significantly in AIDS diarrhea patients, which affected the immune function of the host. The Xielikang capsule modulated the composition of the intestinal microbiota in AIDS diarrhea patients and thus improved immune function and reduced diarrheal symptoms.

Intestinal Microbiota Dysbiosis Promotes Mucosal Barrier Damage and Immune Injury in HIV-Infected Patients

The intestinal microbiota is an "invisible organ" in the human body, with diverse components and complex interactions. Homeostasis of the intestinal microbiota plays a pivotal role in maintaining the normal physiological process and regulating immune homeostasis. By reviewing more than one hundred related studies concerning HIV infection and intestinal microbiota from 2011 to 2023, we found that human immunodeficiency virus (HIV) infection can induce intestinal microbiota dysbiosis, which not only worsens clinical symptoms but also promotes the occurrence of post-sequelae symptoms and comorbidities. In the early stage of HIV infection, the intestinal mucosal barrier is damaged and a persistent inflammatory response is induced. Mucosal barrier damage and immune injury play a pivotal role in promoting the post-sequelae symptoms caused by HIV infection. This review summarizes the relationship between dysbiosis of the intestinal microbiota and mucosal barrier damage during HIV infection and discusses the potential mechanisms of intestinal barrier damage induced by intestinal microbiota dysbiosis and inflammation. Exploring these molecular mechanisms might provide new ideas to improve the efficacy of HIV treatment and reduce the incidence of post-sequelae symptoms.

Immune profiling in Puerto Rican injection drug users with and without HIV-1 infection

Antiretroviral therapy has been effective in suppressing HIV viral load and enabling people living with HIV to experience longer, more conventional lives. However, as people living with HIV are living longer, they are developing aging-related diseases prematurely and are more susceptible to comorbidities that have been linked to chronic inflammation. Coincident with HIV infection and aging, drug abuse has also been independently associated with gut dysbiosis, microbial translocation, and inflammation. Here, we hypothesized that injection drug use would exacerbate HIV-induced immune activation and inflammation, thereby intensifying immune dysfunction. We recruited 50 individuals not using injection drugs (36/50 HIV+) and 47 people who inject drugs (PWID, 12/47 HIV+). All but 3 of the HIV+ subjects were on antiretroviral therapy. Plasma immune profiles were characterized by immunoproteomics, and cellular immunophenotypes were assessed using mass cytometry. The immune profiles of HIV+/PWID-, HIV-/PWID+, and HIV+/PWID+ were each significantly different from controls; however, few differences between these groups were detected, and only 3 inflammatory mediators and 2 immune cell populations demonstrated a combinatorial effect of injection drug use and HIV infection. In conclusion, a comprehensive analysis of inflammatory mediators and cell immunophenotypes revealed remarkably similar patterns of immune dysfunction in HIV-infected individuals and in people who inject drugs with and without HIV-1 infection.

Effects of viremia and CD4 recovery on gut “microbiome-immunity” axis in treatment-naïve HIV-1-infected patients undergoing antiretroviral therapy

BACKGROUND

Human immunodeficiency virus type 1 (HIV-1) infection is characterized by persistent systemic inflammation and immune activation, even in patients receiving effective antiretroviral therapy (ART). Converging data from many cross-sectional studies suggest that gut microbiota (GM) changes can occur throughout including human immunodeficiency virus (HIV) infection, treated by ART; however, the results are contrasting. For the first time, we compared the fecal microbial composition, serum and fecal microbial metabolites, and serum cytokine profile of treatment-naïve patients before starting ART and after reaching virological suppression, after 24 wk of ART therapy. In addition, we compared the microbiota composition, microbial metabolites, and cytokine profile of patients with CD4/CD8 ratio < 1 (immunological non-responders [INRs]) and CD4/CD8 > 1 (immunological responders [IRs]), after 24 wk of ART therapy.

AIM

To compare for the first time the fecal microbial composition, serum and fecal microbial metabolites, and serum cytokine profile of treatment-naïve patients before starting ART and after reaching virological suppression (HIV RNA < 50 copies/mL) after 24 wk of ART.

METHODS

We enrolled 12 treatment-naïve HIV-infected patients receiving ART (mainly based on integrase inhibitors). Fecal microbiota composition was assessed through next generation sequencing. In addition, a comprehensive analysis of a blood broad-spectrum cytokine panel was performed through a multiplex approach. At the same time, serum free fatty acid (FFA) and fecal short chain fatty acid levels were obtained through gas chromatography-mass spectrometry.

RESULTS

We first compared microbiota signatures, FFA levels, and cytokine profile before starting ART and after reaching virological suppression. Modest alterations were observed in microbiota composition, in particular in the viral suppression condition, we detected an increase of Ruminococcus and Succinivibrio and a decrease of Intestinibacter. Moreover, in the same condition, we also observed augmented levels of serum propionic and butyric acids. Contemporarily, a reduction of serum IP-10 and an increase of IL-8 levels were detected in the viral suppression condition. In addition, the same components were compared between IRs and INRs. Concerning the microflora population, we detected a reduction of Faecalibacterium and an increase of Alistipes in INRs. Simultaneously, fecal isobutyric, isovaleric, and 2-methylbutyric acids were also increased in INRs.

CONCLUSION

Our results provided an additional perspective about the impact of HIV infection, ART, and immune recovery on the “microbiome-immunity axis” at the metabolism level. These factors can act as indicators of the active processes occurring in the gastrointestinal tract. Individuals with HIV-1 infection, before ART and after reaching virological suppression with 24 wk of ART, displayed a microbiota with unchanged overall bacterial diversity; moreover, their systemic inflammatory status seems not to be completely restored. In addition, we confirmed the role of the GM metabolites in immune reconstitution.

Signature changes in gut microbiome are associated with increased susceptibility to HIV-1 infection in MSM

BACKGROUND

Men who have sex with men (MSM) have been disproportionately affected by HIV-1 since the beginning of the AIDS pandemic, particularly in the USA and Europe. Compared to men who have sex with women (MSW), MSM have a distinct fecal microbiome regardless of HIV-1 infection. However, it is unclear whether the MSM-associated gut microbiome affects the susceptibility and progression of HIV-1 infection. We studied fecal microbiome profiles, short-chain fatty acids, and blood plasma inflammatory cytokines of 109 HIV-1 seroconverters (SC) from the early, 1984-1985 phase of the HIV-1 pandemic in the Multicenter AIDS Cohort Study (MACS) before and after HIV-1 infection compared to 156 HIV-1-negative MACS MSM (negative controls [NC]).

RESULTS

We found that family Succinivibrionaceae, S24-7, Mogibacteriaceae, Coriobacteriaceae, and Erysipelotrichaceae were significantly higher (p<0.05), whereas Odoribacteraceae, Verucomicrobiaceae, Bacteroidaceae, Barnesiellaceae, and Rikenellaceae were significantly lower (p<0.05), in SC before HIV-1 infection compared to NC. At the species level, Prevotella stercorea, Eubacterium biforme, and Collinsella aerofaciens were significantly higher (p<0.05), and Eubacterium dolichum, Desulfovibrio D168, Alistipes onderdonkii, Ruminococcus torques, Bacteroides fragilis, Bacteroides caccae, Alistipes putredinis, Akkermansia muciniphila, Bacteroides uniformis, and Bacteroides ovatus were significantly lower (p<0.05) in SC before HIV-1 infection compared to NC. After HIV-1 infection, family Prevotellaceae and Victivallaceae and species Bacteroides fragilis and Eubacterium cylindroides were significantly higher (p<0.05) in SC who developed AIDS within 5 years compared to the SC who were AIDS free for more than 10 years without antiretroviral therapy (ART). In addition, family Victivallaceae and species Prevotella stercorea, Coprococcus eutactus, and Butyrivibrio crossotus were significantly higher (p<0.05) and Gemmiger formicilis and Blautia obeum were significantly lower (p<0.05) after HIV-1 infection in SC who developed AIDS within 5-10 years compared to the SC who were AIDS-free for more than 10 years without ART. Furthermore, plasma inflammatory cytokine levels of sCD14, sCD163, interleukin 6, and lipopolysaccharide binding protein were significantly higher in SC with p<0.05 before HIV-1 infection compared to NC.

CONCLUSIONS

Our results suggest that pathogenic changes in the gut microbiome were present in MSM several months prior to infection with HIV-1 in the early phase of the AIDS pandemic in the USA. This was associated with increased inflammatory biomarkers in the blood and risk for development of AIDS. Video abstract.

A specific structure and high richness characterize intestinal microbiota of HIV-exposed seronegative individuals

Intestinal microbiota facilitates food breakdown for energy metabolism and influences the immune response, maintaining mucosal homeostasis. Overall, HIV infection is associated with intestinal dysbiosis and immune activation, which has been related to seroconversion in HIV-exposed individuals. However, it is unclear whether microbiota dysbiosis is the cause or the effect of immune alterations and disease progression or if it could modulate the risk of acquiring the HIV infection. We characterize the intestinal microbiota and determine its association with immune regulation in HIV-exposed seronegative individuals (HESN), HIV-infected progressors (HIV+), and healthy control (HC) subjects. For this, feces and blood were collected. The microbiota composition of HESN showed a significantly higher alpha (p = 0.040) and beta diversity (p = 0.006) compared to HC, but no differences were found compared to HIV+. A lower Treg percentage was observed in HESN (1.77%) than HC (2.98%) and HIV+ (4.02%), with enrichment of the genus Butyrivibrio (p = 0.029) being characteristic of this profile. Moreover, we found that Megasphaera (p = 0.017) and Victivallis (p = 0.0029) also are enriched in the microbiota composition in HESN compared to HC and HIV+ subjects. Interestingly, an increase in Succinivibrio and Prevotella, and a reduction in Bacteroides genus, which is typical of HIV-infected individuals, were observed in both HESN and HIV+, compared to HC. Thus, HESNs have a microbiota profile, similar to that observed in HIV+, most likely because HESN are cohabiting with their HIV+ partners.

Colostrum Therapy for Human Gastrointestinal Health and Disease

There is increasing awareness that a broad range of gastrointestinal diseases, and some systemic diseases, are characterized by failure of the mucosal barrier. Bovine colostrum is a complex biological fluid replete with growth factors, nutrients, hormones, and paracrine factors which have a range of properties likely to contribute to mucosal healing in a wide range of infective, inflammatory, and injury conditions. In this review, we describe the anatomy and physiology of the intestinal barrier and how it may fail. We survey selected diseases in which disordered barrier function contributes to disease pathogenesis or progression, and review the evidence for or against efficacy of bovine colostrum in management. These disorders include enteropathy due to non-steroidal anti-inflammatory drugs (NSAIDs), inflammatory bowel disease (IBD), necrotizing enterocolitis, infectious diarrhea, intestinal failure, and damage due to cancer therapy. In animal models, bovine colostrum benefits NSAID enteropathy, IBD, and intestinal failure. In human trials, there is substantial evidence of efficacy of bovine colostrum in inflammatory bowel disease and in infectious diarrhea. Given the robust scientific rationale for using bovine colostrum as a promoter of mucosal healing, further work is needed to define its role in therapy.

Long-Term Suppressive cART Is Not Sufficient to Restore Intestinal Permeability and Gut Microbiota Compositional Changes

Background: We explored the long-term effects of cART on markers of gut damage, microbial translocation, and paired gut/blood microbiota composition, with a focus on the role exerted by different drug classes.

Methods: We enrolled 41 cART naïve HIV-infected subjects, undergoing blood and fecal sampling prior to cART (T0) and after 12 (T12) and 24 (T24) months of therapy. Fifteen HIV-uninfected individuals were enrolled as controls. We analyzed: (i) T-cell homeostasis (flow cytometry); (ii) microbial translocation (sCD14, EndoCab, 16S rDNA); (iii) intestinal permeability and damage markers (LAC/MAN, I-FABP, fecal calprotectin); (iv) plasma and fecal microbiota composition (alpha- and beta-diversity, relative abundance); (v) functional metagenome predictions (PICRUSt).

Results: Twelve and twenty four-month successful cART resulted in a rise in EndoCAb (p = 0.0001) and I-FABP (p = 0.039) vis-à-vis stable 16S rDNA, sCD14, calprotectin and LAC/MAN, along with reduced immune activation in the periphery. Furthermore, cART did not lead to substantial modifications of microbial composition in both plasma and feces and metabolic metagenome predictions. The stratification according to cART regimens revealed a feeble effect on microbiota composition in patients on NNRTI-based or INSTI-based regimens, but not PI-based regimens.

Conclusions: We hereby show that 24 months of viro-immunological effective cART, while containing peripheral hyperactivation, exerts only minor effects on the gastrointestinal tract. Persistent alteration of plasma markers indicative of gut structural and functional impairment seemingly parallels enduring fecal dysbiosis, irrespective of drug classes, with no effect on metabolic metagenome predictions.

Altered gut microbiota correlate with different immune responses to HAART in HIV-infected individuals

Background

Although gut microbiota dysbiosis has been reported in HIV infected individuals recently, the relationship between the gut microbiota and immune activation in patients with different immune responses to highly active antiretroviral therapy (HAART) is still not well understood. Gut microbiota and immune activation were studied in 36 non-HIV-infected subjects (healthy controls) and 58 HIV-infected individuals, including 28 immunological responders (IR) and 30 immunological non-responders (INR) (≥500 and < 200 CD4+ T-cell counts/μl after 2 years of HIV-1 viral suppression respectively) without comorbidities.

Results

Metagenome sequencing revealed that HIV-infected immunological responders and immunological non-responders could not recover completely from the gut microbiota dysbiosis. At a 97% similarity level, the relative abundances of Fusobacterium, Ruminococcus gnavus and Megamonas were greater, whereas Faecalibacterium, Alistipes, Bifidobacterium, Eubacterium rectale and Roseburia were more depleted in the IR and INR groups than those in the healthy controls. Ruminococcaceae and Alistipes were positively correlated with nadir and current CD4+ T-cell counts, but negatively correlated with CD8 + CD57+ T-cell counts. Inflammation markers and translocation biomarkers (LPS) levels were positively correlated with the abundances of genera Ruminococcus and Fusobacterium but were negatively correlated with the genus Faecalibacterium. The relative abundances of Escherichia-Shigella and Blautia were significantly higher in the IR than those in the INR group. Escherichia-Shigella were negatively correlated with the CD4/CD8 ratio but positively correlated with the amount of CD8 + CD57+ T-cells. Roseburia and Blautia were negatively associated with nadir CD4+ T-cell and positively associated with CD8 + CD57+ T-cell counts.

Conclusions

Gut microbiota dysbiosis may be one of the factors contributing to different immune responses and treatment outcomes to HAART.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-020-02074-1.

Effect of Opioid Use on Immune Activation and HIV Persistence on ART

While there is an emerging consensus that engagement of the Mu opioid receptor by opioids may modulate various stages the HIV life cycle (e.g.: increasing cell susceptibility to infection, promoting viral transcription, and depressing immune responses to virally-infected cells), the overall effect on latency and viral reservoirs remains unclear. Importantly, the hypothesis that the increase in immune activation observed in chronic opioid users by direct or indirect mechanisms (i.e., microbial translocation) would lead to a larger HIV reservoir after ART-suppression has not been supported to date. The potential for a subsequent decrease in reservoirs after ART-suppression has been postulated and is supported by early reports of opioid users having lower latent HIV burden. Here, we review experimental data supporting the link between opioid use and HIV modulation, as well as the scientific premise for expecting differential changes in immune activation and HIV reservoir between different medications for opioid use disorder. A better understanding of potential changes in HIV reservoirs relative to the engagement of the Mu opioid receptor and ART-mediated immune reconstitution will help guide future cure-directed studies in persons living with HIV and opioid use disorder. Graphical Abstract Review. HIV replication, immune activation and dysbiosis: opioids may affect immune reconstitution outcomes despite viral suppression.

Safety and efficacy of probiotic administration to preterm infants: ten common questions

In spite of a large number of randomized placebo-controlled clinical trials and observational cohort studies including >50,000 preterm infants from 29 countries that have demonstrated a decrease in the risk of necrotizing enterocolitis, death, and sepsis, routine prophylactic probiotic administration to preterm infants remains uncommon in much of the world. This manuscript reflects talks given at NEC Society Symposium in 2019 and is not intended to be a state-of-the-art review or systematic review, but a summary of the probiotic-specific aspects of the symposium with limited additions including a recent strain-specific network analysis and position statement from the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN). We address ten common questions related to the intestinal microbiome and probiotic administration to the preterm infant.

Antiviral Activity of Fecal Water Samples from HIV-1 Infected Subjects Treated with a Specific Probiotic Formulation

OBJECTIVES

The aim of the study was to investigate if the supplementation with multistrain probiotics may be able to modulate T cell response in HIV-1 infected patients and to evaluate the anti-HIV activity of probiotic by studying fecal water (FW) samples.

METHODS

Three HIV-1-positive patients (Pt1, Pt2 and Pt3) on long-term suppressive combined antiretroviral therapy (cART) received a specific multi-strain probiotic supplementation (Vivomixx ®), for six months (T6). Levels of T cell subsets were evaluated by flow cytometry. Anti- HIV activity of FW samples was evaluated in vitro.

RESULTS

CD4+ T cells levels increased in all HIV-1 infected patients whereas activation markers (CD38 and HLA-DR) were decreased both on CD4+ and CD8+ T cells. FW samples presented an increased inhibitory activity against HIV-1 compared to T0 (FW-Pt1: T0 =40%, T6 = 65% of reduction; FW Pt2: T0 = 26%, T6 = 46% of reduction; FW Pt3: T0 = 47%, T6 = 94% of reduction).

DISCUSSION

Our data suggest that the administration of the specific probiotic formulation improves the antiviral status of people living with HIV-1 under cART, also modulating T cell response.

CONCLUSION

Anti-HIV activity of FW may have several public health and social implications for sexually transmitted diseases that need to be further explored.