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Nganou-Makamdop K, Douek DC. The Gut and the Translocated Microbiomes in HIV Infection: Current Concepts and Future Avenues. Pathog Immun 2024; 9:168-194. [PMID: 38807656 PMCID: PMC11132393 DOI: 10.20411/pai.v9i1.693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/03/2024] [Indexed: 05/30/2024] Open
Abstract
It is widely acknowledged that HIV infection results in disruption of the gut's mucosal integrity partly due a profound loss of gastrointestinal CD4+ T cells that are targets of the virus. In addition, systemic inflammation and immune activation that drive disease pathogenesis are reduced but not normalized by antiretroviral therapy (ART). It has long been postulated that through the process of microbial translocation, the gut microbiome acts as a key driver of systemic inflammation and immune recovery in HIV infection. As such, many studies have aimed at characterizing the gut microbiota in order to unravel its influence in people with HIV and have reported an association between various bacterial taxa and inflammation. This review assesses both contra-dictory and consistent findings among several studies in order to clarify the overall mechanisms by which the gut microbiota in adults may influence immune recovery in HIV infection. Independently of the gut microbiome, observations made from analysis of microbial products in the blood provide direct insight into how the translocated microbiome may drive immune recovery. To help better understand strengths and limitations of the findings reported, this review also highlights the numerous factors that can influence microbiome studies, be they experimental methodologies, and host-intrinsic or host-extrinsic factors. Altogether, a fuller understanding of the interplay between the gut microbiome and immunity in HIV infection may contribute to preventive and therapeutic approaches.
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Affiliation(s)
| | - Daniel C. Douek
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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Carter KA, France MT, Rutt L, Bilski L, Martinez-Greiwe S, Regan M, Brotman RM, Ravel J. Sexual transmission of urogenital bacteria: whole metagenome sequencing evidence from a sexual network study. mSphere 2024; 9:e0003024. [PMID: 38358269 PMCID: PMC10964427 DOI: 10.1128/msphere.00030-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 01/21/2024] [Indexed: 02/16/2024] Open
Abstract
Sexual transmission of the urogenital microbiota may contribute to adverse sexual and reproductive health outcomes. The extent of sexual transmission of the urogenital microbiota is unclear as prior studies largely investigated specific pathogens. We used epidemiologic data and whole metagenome sequencing to characterize urogenital microbiota strain concordance between participants of a sexual network study. Individuals who screened positive for genital Chlamydia trachomatis were enrolled and referred their sexual contacts from the prior 60-180 days. Snowball recruitment of sexual contacts continued for up to four waves. Vaginal swabs and penile urethral swabs were collected for whole metagenome sequencing. We evaluated bacterial strain concordance using inStrain and network analysis. We defined concordance as ≥99.99% average nucleotide identity over ≥50% shared coverage; we defined putative sexual transmission as concordance between sexual contacts with <5 single-nucleotide polymorphisms per megabase. Of 138 participants, 74 (54%) were female; 120 (87%) had genital chlamydia; and 43 (31%) were recruited contacts. We identified 115 strain-concordance events among 54 participants representing 25 bacterial species. Seven events (6%) were between sexual contacts including putative heterosexual transmission of Fannyhessea vaginae, Gardnerella leopoldii, Prevotella amnii, Sneathia sanguinegens, and Sneathia vaginalis (one strain each), and putative sexual transmission of Lactobacillus iners between female contacts. Most concordance events (108, 94%) were between non-contacts, including eight female participants connected through 18 Lactobacillus crispatus and 3 Lactobacillus jensenii concordant strains, and 14 female and 2 male participants densely interconnected through 52 Gardnerella swidsinskii concordance events.IMPORTANCEEpidemiologic evidence consistently indicates bacterial vaginosis (BV) is sexually associated and may be sexually transmitted, though sexual transmission remains subject to debate. This study is not capable of demonstrating BV sexual transmission; however, we do provide strain-level metagenomic evidence that strongly supports heterosexual transmission of BV-associated species. These findings strengthen the evidence base that supports ongoing investigations of concurrent male partner treatment for reducing BV recurrence. Our data suggest that measuring the impact of male partner treatment on F. vaginae, G. leopoldii, P. amnii, S. sanguinegens, and S. vaginalis may provide insight into why a regimen does or does not perform well. We also observed a high degree of strain concordance between non-sexual-contact female participants. We posit that this may reflect limited dispersal capacity of vaginal bacteria coupled with individuals' comembership in regional transmission networks where transmission may occur between parent and child at birth, cohabiting individuals, or sexual contacts.
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Affiliation(s)
- Kayla A. Carter
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Michael T. France
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Lindsay Rutt
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Lisa Bilski
- School of Nursing, University of Maryland, Baltimore, Maryland, USA
| | | | - Mary Regan
- School of Nursing, University of Maryland, Baltimore, Maryland, USA
| | - Rebecca M. Brotman
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Day E, Galiwango RM, Park D, Huibner S, Aziz M, Anok A, Nnamutete J, Isabirye Y, Wasswa JB, Male D, Kigozi G, Tobian AA, Prodger JL, Liu CM, Kaul R. Insertive vaginal sex is associated with altered penile immunology and enrichment of Gardnerella vaginalis in uncircumcised Ugandan men. Am J Reprod Immunol 2024; 91:e13801. [PMID: 38282609 PMCID: PMC10825315 DOI: 10.1111/aji.13801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/13/2023] [Accepted: 11/17/2023] [Indexed: 01/30/2024] Open
Abstract
PROBLEM HIV susceptibility is linked to the penile immune milieu (particularly IL-8 levels) and microbiome. The effects of insertive vaginal sex itself on penile immunology and microbiota are not well described. METHOD OF STUDY We compared the immune milieu and microbiology of the coronal sulcus (CS) and distal urethra in 47 uncircumcised Ugandan men reporting ever (n = 42) or never (n = 5) having had vaginal intercourse. Soluble immune factors were assayed by multiplex ELISA, and penile bacteria abundance by 16S rRNA qPCR and sequencing. Co-primary endpoints were penile levels of IL-8 and soluble E-cadherin. RESULTS Independent of classical STIs, men reporting prior vaginal sex demonstrated elevated IL-8 levels in both the coronal sulcus (1.78 vs. 0.81 log10 pg/mL, p = .021) and urethra (2.93 vs. 2.30 log10 pg/mL; p = .003), with a strong inverse relationship between urethral IL-8 levels and the time from last vaginal sex (r = -0.436; p = .004). Vaginal sex was also associated with elevated penile IL-1α/β and soluble E-cadherin (sEcad), a marker of epithelial disruption. Gardnerella vaginalis (Gv) was only present in the penile microbiome of men reporting prior vaginal sex, and urethral Gv absolute abundance was strongly associated with urethral inflammation (r = 0.556; p < .001); corynebacteria were enriched in the CS of men reporting no prior vaginal sex and were associated with reduced CS inflammation. CONCLUSIONS Sexual intercourse was associated with sustained changes in penile immunology, potentially mediated through microbial alterations, in particular the urethral abundance of G. vaginalis. Future studies should further characterize the effects of sexual debut on penile bacteria and immunology.
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Affiliation(s)
- Erin Day
- Department of Microbiology and Immunology, Western University, Ontario, Canada
| | - Ronald M. Galiwango
- Departments of Immunology and Medicine, University of Toronto, Ontario, Canada
- Rakai Health Sciences Program, Kalisizo, Uganda
| | - Daniel Park
- George Washington Milken Institute School of Public Health, Washington DC, USA
| | - Sanja Huibner
- Departments of Immunology and Medicine, University of Toronto, Ontario, Canada
| | - Maliha Aziz
- George Washington Milken Institute School of Public Health, Washington DC, USA
| | - Aggrey Anok
- Rakai Health Sciences Program, Kalisizo, Uganda
| | | | | | | | - Deo Male
- Rakai Health Sciences Program, Kalisizo, Uganda
| | | | - Aaron A.R. Tobian
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jessica L. Prodger
- Department of Microbiology and Immunology, Western University, Ontario, Canada
| | - Cindy M. Liu
- George Washington Milken Institute School of Public Health, Washington DC, USA
| | - Rupert Kaul
- Departments of Immunology and Medicine, University of Toronto, Ontario, Canada
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Masenga SK, Mweene BC, Luwaya E, Muchaili L, Chona M, Kirabo A. HIV-Host Cell Interactions. Cells 2023; 12:1351. [PMID: 37408185 DOI: 10.3390/cells12101351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 07/07/2023] Open
Abstract
The development of antiretroviral drugs (ARVs) was a great milestone in the management of HIV infection. ARVs suppress viral activity in the host cell, thus minimizing injury to the cells and prolonging life. However, an effective treatment has remained elusive for four decades due to the successful immune evasion mechanisms of the virus. A thorough understanding of the molecular interaction of HIV with the host cell is essential in the development of both preventive and curative therapies for HIV infection. This review highlights several inherent mechanisms of HIV that promote its survival and propagation, such as the targeting of CD4+ lymphocytes, the downregulation of MHC class I and II, antigenic variation and an envelope complex that minimizes antibody access, and how they collaboratively render the immune system unable to mount an effective response.
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Affiliation(s)
- Sepiso K Masenga
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Campus, Livingstone 10101, Zambia
- Vanderbilt University Medical Center, Department of Medicine, Division of Clinical Pharmacology, Room 536 Robinson Research Building, Nashville, TN 37232-6602, USA
| | - Bislom C Mweene
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Campus, Livingstone 10101, Zambia
| | - Emmanuel Luwaya
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Campus, Livingstone 10101, Zambia
| | - Lweendo Muchaili
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Campus, Livingstone 10101, Zambia
| | - Makondo Chona
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Campus, Livingstone 10101, Zambia
| | - Annet Kirabo
- Vanderbilt University Medical Center, Department of Medicine, Division of Clinical Pharmacology, Room 536 Robinson Research Building, Nashville, TN 37232-6602, USA
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Prodger JL, Galiwango RM, Tobian AAR, Park D, Liu CM, Kaul R. How Does Voluntary Medical Male Circumcision Reduce HIV Risk? Curr HIV/AIDS Rep 2022; 19:484-490. [PMID: 36308579 PMCID: PMC9617235 DOI: 10.1007/s11904-022-00634-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2022] [Indexed: 01/31/2023]
Abstract
PURPOSE OF REVIEW Voluntary medical male circumcision (VMMC) is a surgical procedure that reduces HIV acquisition risk by almost two-thirds. However, global implementation is lagging, in part due to VMMC hesitancy. A better understanding of the mechanism(s) by which this procedure protects against HIV may increase acceptance of VMMC as an HIV risk reduction approach among health care providers and their clients. RECENT FINDINGS HIV acquisition in the uncircumcised penis occurs preferentially across the inner foreskin tissues, due to increased susceptibility that is linked to elevated inflammatory cytokine levels in the sub-preputial space and an increased tissue density of HIV-susceptible CD4 + T cells. Inflammation can be caused by sexually transmitted infections, but is more commonly induced by specific anaerobic components of the penile microbiome. Circumcision protects by both directly removing the susceptible tissues of the inner foreskin, and by inducing a less inflammatory residual penile microbiome. VMMC reduces HIV susceptibility by removing susceptible penile tissues, and also through impacts on the penile immune and microbial milieu. Understanding these mechanisms may not only increase VMMC acceptability and reinvigorate global VMMC programs, but may also lead to non-surgical HIV prevention approaches focused on penile immunology and/or microbiota.
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Affiliation(s)
- Jessica L Prodger
- Departments of Microbiology and Immunology and Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON, N6A 5C1, Canada
| | | | - Aaron A R Tobian
- Department of Pathology, Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Daniel Park
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Cindy M Liu
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Rupert Kaul
- Departments of Medicine and Immunology, University of Toronto, Medical Sciences Building Rm. 6356, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- University Health Network, Toronto, ON, Canada.
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