Effect of Lactobacillus rhamnosus GG Supplementation on Intestinal Inflammation Assessed by PET/MRI Scans and Gut Microbiota Composition in HIV-Infected Individuals

Mechanisms of HIV-immunologic non-responses and research trends based on gut microbiota

With the increasing number of people with HIV (PWH) and the use of antiretroviral treatment (ART) for PWH, HIV has gradually become a chronic infectious disease. However, some infected individuals develop issues with immunologic non-responses (INRs) after receiving ART, which can lead to secondary infections and seriously affect the life expectancy and quality of life of PWH. Disruption of the gut microbiota is an important factor in immune activation and inflammation in HIV/AIDS, thus stabilizing the gut microbiota to reduce immune activation and inflammation and promoting immune reconstitution may become a direction for the treatment of HIV/AIDS. This paper, based on extensive literature review, summarizes the definition, mechanisms, and solutions for INRs, starting from the perspective of gut microbiota.

Probiotic, Postbiotic, and Paraprobiotic Effects of Lactobacillus rhamnosus as a Modulator of Obesity-Associated Factors

Obesity is a pandemic currently affecting the world's population that decreases the quality of life and promotes the development of chronic non-communicable diseases. Lactobacillus rhamnosus is recognized for multiple positive effects on obesity and overall health. In fact, such effects may occur even when the microorganisms do not remain alive (paraprobiotic effects). This raises the need to elucidate the mechanisms by which obesity-associated factors can be modulated. This narrative review explores recent findings on the effects of L. rhamnosus, particularly, its postbiotic and paraprobiotic effects, on the modulation of adiposity, weight gain, oxidative stress, inflammation, adipokines, satiety, and maintenance of intestinal integrity, with the aim of providing a better understanding of its mechanisms of action in order to contribute to streamlining its clinical and therapeutic applications. The literature shows that L. rhamnosus can modulate obesity-associated factors when analyzed in vitro and in vivo. Moreover, its postbiotic and paraprobiotic effects may be comparable to the more studied probiotic actions. Some mechanisms involve regulation of gene expression, intracellular signaling, and enteroendocrine communication, among others. We conclude that the evidence is promising, although there are still multiple knowledge gaps that require further study in order to fully utilize L. rhamnosus to improve human health.

Protective Mechanisms of Vaginal Lactobacilli against Sexually Transmitted Viral Infections

The healthy cervicovaginal microbiota is dominated by various Lactobacillus species, which support a condition of eubiosis. Among their many functions, vaginal lactobacilli contribute to the maintenance of an acidic pH, produce antimicrobial compounds, and modulate the host immune response to protect against vaginal bacterial and fungal infections. Increasing evidence suggests that these beneficial bacteria may also confer protection against sexually transmitted infections (STIs) caused by viruses such as human papillomavirus (HPV), human immunodeficiency virus (HIV) and herpes simplex virus (HSV). Viral STIs pose a substantial public health burden globally, causing a range of infectious diseases with potentially severe consequences. Understanding the molecular mechanisms by which lactobacilli exert their protective effects against viral STIs is paramount for the development of novel preventive and therapeutic strategies. This review aims to provide more recent insights into the intricate interactions between lactobacilli and viral STIs, exploring their impact on the vaginal microenvironment, host immune response, viral infectivity and pathogenesis, and highlighting their potential implications for public health interventions and clinical management strategies.

Effect of intake of probiotics and probiotic fermented foods on clinical outcomes among people living with HIV: A systematic review and meta-analysis

OBJECTIVE

The objective of the study was to determine the effect of probiotics and of probiotic-fermented foods on CD4 T-cell count, viral load, anaemia and body mass index (BMI) among people living with HIV (PLHIV).

METHODS

In this article, we systematically reviewed the evidence on the influence of probiotic supplementation on CD4 lymphocyte count, viral load and anaemia among PLHIV on highly active antiretroviral therapy (HAART) and those who were HAART-naive. Medical literature databases identified randomised trials and pre-post studies of probiotic supplementation and HIV-related outcomes, and random effects meta-analysis was conducted.

RESULTS

The preponderance of the evidence suggests that probiotic supplementation only improved CD4 lymphocyte count modestly, with quantitatively greater impact among individuals who were HAART-naive compared to HAART-experienced individuals. Probiotic supplementation improved CD4 lymphocyte count by 53 cells/mm3 (95% CI: 22 to 85) from 18 studies. Probiotic supplementation however reduced haemoglobin concentration by -2.1 g/L (95% CI: -4.0 to -0.2). Although viral load remain unchanged in HAART-experienced participants following probiotic supplementation, HAART-naïve participants saw a decrease in viral load. There were too few studies on the impact of probiotic supplementation on viral load (N = 1).

CONCLUSION

Probiotic supplementation resulted in a modest increase in CD4 lymphocyte count among HAART-naive individuals with no significant change observed among HAART-experienced ones. Viral load and haemoglobin concentration also remained unchanged following probiotic supplementation. Further rigorous and well-powered studies may evaluate the effect of probiotic supplementation on important clinical outcomes among PLHIV on HAART.

Lactocaseibacillus rhamnosus zz-1 Supplementation Mitigates Depression-Like Symptoms in Chronic Stress-Induced Depressed Mice via the Microbiota-Gut-Brain Axis

Accumulating evidence has revealed an association between depression and disordered intestinal microecology. The discovery of psychobiotics has provided a promising perspective for studying the treatment of psychiatric disorders. Here, we aimed to investigate the antidepressant abilities of Lactocaseibacillus rhamnosus zz-1 (LRzz-1) and elucidate the underlying mechanisms. The viable bacteria (2 × 10⁹ CFU/day) were orally supplemented to depressed C57BL/6 mice induced by chronic unpredictable mild stress (CUMS), and the behavioral, neurophysiological, and intestinal microbial effects were assessed, with fluoxetine used as a positive control. The treatment with LRzz-1 effectively mitigated the depression-like behavioral disorders of depressed mice and reduced the expression of inflammatory cytokine mRNA (IL-1β, IL-6, and TNF-α) in the hippocampus. In addition, LRzz-1 treatment also improved tryptophan metabolic disorder in the mouse hippocampus, as well as its peripheral circulation. These benefits are associated with the mediation of microbiome-gut-brain bidirectional communication. CUMS-induced depression impaired the intestinal barrier integrity and microbial homeostasis in mice, neither of which was restored by fluoxetine. LRzz-1 prevented intestinal leakage and significantly ameliorated epithelial barrier permeability by up-regulating tight-junction proteins (including ZO-1, occludin, and claudin-1). In particular, LRzz-1 improved the microecological balance by normalizing the threatened bacteria (e.g., Bacteroides and Desulfovibrio), exerting beneficial regulation (e.g., Ruminiclostridium 6 and Alispites), and modifying short-chain fatty acid metabolism. In summary, LRzz-1 showed considerable antidepressant-like effects and exhibited more comprehensive intestinal microecological regulation than other drugs, which offers novel insights that can facilitate the development of depression therapeutic strategies.

Lactobacillus rhamnosus zz-1 exerts preventive effects on chronic unpredictable mild stress-induced depression in mice via regulating the intestinal microenvironment

Depression remains one of the most prevalent psychiatric disorders, and it has been confirmed that it is related to the dysfunction of the microbiota-gut-brain axis. Manipulation of the gut microenvironment by probiotics might improve mental health and prevent stress-related psychiatric disorders. The present study aimed to determine whether Lactobacillus rhamnosus (L. rhamnosus) zz-1 could prevent the occurrence of depression and its potential mechanisms using a mouse model with chronic unpredictable mild stress (CUMS). The results indicated that L. rhamnosus zz-1 intervention ameliorated CUMS-induced depression-like behaviors of mice with reduced body growth rate, lowered sucrose preference, increased immobility time, as well as decreased curiosity and mobility. Moreover, L. rhamnosus zz-1 significantly inhibited hormones released due to hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, alleviated CUMS-induced deficits of monoamine neurotransmitters, and increased the expression of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB). These benefits were partially linked to the regulation of the intestinal microenvironment. L. rhamnosus zz-1 alleviated intestinal damage and reduced intestinal inflammation of the depressed mice. Meanwhile, L. rhamnosus zz-1 effectively adjusted the dysbiosis of mouse gut microbiota induced by CUMS, such as changes in the abundance of the Lachnospiraceae NK4A136 group, Bacteroides, and Muribaculum. Taken together, these results demonstrated that L. rhamnosus zz-1 was effective in preventing depression from chronic stress, adding new evidence to support the mental benefits of probiotics.

Lacticaseibacillus rhamnosus: A Suitable Candidate for the Construction of Novel Bioengineered Probiotic Strains for Targeted Pathogen Control

Probiotics, with their associated beneficial effects, have gained popularity for the control of foodborne pathogens. Various sources are explored with the intent to isolate novel robust probiotic strains with a broad range of health benefits due to, among other mechanisms, the production of an array of antimicrobial compounds. One of the shortcomings of these wild-type probiotics is their non-specificity. A pursuit to circumvent this limitation led to the advent of the field of pathobiotechnology. In this discipline, specific pathogen gene(s) are cloned and expressed into a given probiotic to yield a novel pathogen-specific strain. The resultant recombinant probiotic strain will exhibit enhanced species-specific inhibition of the pathogen and its associated infection. Such probiotics are also used as vehicles to deliver therapeutic agents. As fascinating as this approach is, coupled with the availability of numerous probiotics, it brings a challenge with regard to deciding which of the probiotics to use. Nonetheless, it is indisputable that an ideal candidate must fulfil the probiotic selection criteria. This review aims to show how Lacticaseibacillus rhamnosus, a clinically best-studied probiotic, presents as such a candidate. The objective is to spark researchers’ interest to conduct further probiotic-engineering studies using L. rhamnosus, with prospects for the successful development of novel probiotic strains with enhanced beneficial attributes.

Probiotics to HIV-Infected Immunological Nonresponders: Altered Mucosal Immunity and Microbial Diversity Restricted to Ileum

BACKGROUND

HIV-infected immunological nonresponders (INRs) have increased risk of non-AIDS morbidity and compromised gut barrier immunity. Probiotics are widely used to improve health. We assessed the effects of probiotics in INRs with a comprehensive analysis of gut immunity and microbiome in terminal ileum and sigmoid colon.

METHODS

The study involved clinical intervention with five-strain probiotic capsules (1.2 × 1010 CFUs/d) for 8 weeks in 20 INRs with CD4+ T-cell counts <400 cells/µL and plasma HIV RNA <50 copies/mL for more than 3.5 years. Colonoscopy with sampling of gut biopsies from terminal ileum and sigmoid colon and fecal and blood sampling were performed before and after the intervention. Flow cytometry (cytokine production, immune activation, and exhaustion), ELISA (inflammation, microbial translocation, and enterocyte damage), and 16S rRNA sequencing analyses were applied.

RESULTS

In the terminal ileum, increased alpha diversity, increased abundance of Bifidobacterium sp., and decreased frequencies of IL-22+ CD4+ T cells were observed. The increased abundance of Bifidobacterium sp. in the terminal ileum correlated with increased fraction of CD4+ T cells in the same compartment (r = 0.54, P = 0.05) and increased CD4/CD8 ratio in peripheral blood (r = 0.49, P = 0.05). There were no corresponding changes in the sigmoid colon and no changes in fecal microbiome. Probiotic intervention did not affect peripheral blood CD4 count, viral load, or soluble markers of inflammation and microbial translocation.

CONCLUSIONS

Probiotics induced segment-specific changes in the terminal ileum but did not affect systemic CD4 counts in INRs. Further clinical studies are warranted to recommend probiotics to INRs.

The Potential of Probiotics to Eradicate Gut Carriage of Pathogenic or Antimicrobial-Resistant Enterobacterales

Probiotic supplements have been used to decrease the gut carriage of antimicrobial-resistant Enterobacterales through changes in the microbiota and metabolomes, nutrition competition, and the secretion of antimicrobial proteins. Many probiotics have shown Enterobacterales-inhibiting effects ex vivo and in vivo. In livestock, probiotics have been widely used to eradicate colon or environmental antimicrobial-resistant Enterobacterales colonization with promising efficacy for many years by oral supplementation, in ovo use, or as environmental disinfectants. In humans, probiotics have been used as oral supplements for infants to decease potential gut pathogenic Enterobacterales, and probiotic mixtures, especially, have exhibited positive results. In contrast to the beneficial effects in infants, for adults, probiotic supplements might decrease potentially pathogenic Enterobacterales, but they fail to completely eradicate them in the gut. However, there are several ways to improve the effects of probiotics, including the discovery of probiotics with gut-protection ability and antimicrobial effects, the modification of delivery methods, and the discovery of engineered probiotics. The search for multifunctional probiotics and synbiotics could render the eradication of “bad” Enterobacterales in the human gut via probiotic administration achievable in the future.

Effects of Probiotics on Diarrhea and CD4 Cell Count in People Living With HIV: A Systematic Review and Meta-Analysis

Gastrointestinal probiotics play an important role in maintaining intestinal bacteria homeostasis. They might benefit people with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), which remains a global health challenge. However, there is a controversy regarding the efficacy of probiotics for the treatment of AIDS. This study systematically reviewed the evidence of the effects of existing probiotic interventions on AIDS and sought to provide information on the role of probiotics in the treatment of HIV/AIDS patients. A meta-analysis of studies identified by screening multiple databases was performed using a fixed-effects model in Review Manager 5.2 software. The meta-analysis showed that probiotics could reduce the incidence of AIDS-related diarrhea (RR = 0.60 (95% CI: 0.44–0.82), p = 0.001). The short-term use of probiotics (supplementation duration shorter than 30 days) did not reduce the incidence of diarrhea (RR = 0.76 (95% CI: 0.51–1.14), p = 0.19), while the long-term use of probiotics (supplementation duration longer than 30 days) reduced diarrhea (RR = 0.47 (95% CI: 0.29–0.76), p = 0.002). Probiotics had no effect on CD4 cell counts in HIV/AIDS patients (MD = 21.24 (95% CI: −12.95–55.39), p = 0.22). Our data support that probiotics were associated with an obvious reduction in AIDS-related diarrhea, which indicates the need for additional research on this potential preventive strategy for AIDS.

Lights and Shadows of Microbiota Modulation and Cardiovascular Risk in HIV Patients

Human immunodeficiency virus (HIV) infection is associated with premature aging and the development of aging-related comorbidities, such as cardiovascular disease (CVD). Gut microbiota (GM) disturbance is involved in these comorbidities and there is currently interest in strategies focused on modulating GM composition and/or functionality. Scientific evidence based on well-designed clinical trials is needed to support the use of prebiotics, probiotics, symbiotics, and fecal transplantation (FT) to modify the GM and reduce the incidence of CVD in HIV-infected patients. We reviewed the data obtained from three clinical trials focused on prebiotics, 25 trials using probiotics, six using symbiotics, and four using FT. None of the trials investigated whether these compounds could reduce CVD in HIV patients. The huge variability observed in the type of compound as well as the dose and duration of administration makes it difficult to adopt general recommendations and raise serious questions about their application in clinical practice.

Probiotics to manage inflammation in HIV infection

PURPOSE OF REVIEW

To evaluate the current scientific basis for administering probiotics to people living with HIV (PLHIV) to alleviate chronic inflammation and subsequently improve their prognosis.

RECENT FINDINGS

The gut microbiome is a potential contributing factor to low-grade inflammation in HIV infection, and there is a scientific rationale for attempting to attenuate inflammation by administering probiotics. Sixteen reports from clinical studies in antiretroviral therapy (ART)-treated PLHIV assessing inflammation after probiotic intervention have been identified; half of them randomized control trials (RCT). Some of the studies report improvement in some parameters of inflammation, but results are inconsistent. No studies report improvement of CD4 counts. None of the RCTs report improvements in any markers of inflammation when analyzed according to protocol.

SUMMARY

Current scientific evidence does not support the use of probiotics to alleviate inflammation in HIV infection. The potential effect of probiotic intervention in ART-treated PLHIV with high risk for inflammation remains to be investigated.

Electroacupuncture may alleviate behavioral defects via modulation of gut microbiota in a mouse model of Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) is a chronic neurodegenerative disease involving non-motor symptoms, of which gastrointestinal disorders are the most common. In light of recent results, intestinal dysfunction may be involved in the pathogenesis of PD. Electroacupuncture (EA) has shown potential effects, although the underlying mechanism remains mostly unknown. We speculated that EA could relieve the behavioral defects of PD, and that this effect would be associated with modulation of the gut microbiota.

METHODS

Mice were randomly divided into three groups: control, PD + MA (manual acupuncture), and PD + EA. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) was used to establish the mouse model of PD. Rotarod performance tests, open field tests, and pole tests were carried out to assess motor deficiencies. Immunohistochemistry was conducted to examine the survival of dopaminergic neurons. 16S ribosomal RNA (rRNA) gene sequencing was applied to investigate the alterations of the gut microbiome. Quantitative real-time polymerase chain reaction (PCR) was performed to characterize the messenger RNA (mRNA) levels of pro-inflammatory and anti-inflammatory cytokines.

RESULTS

We found that EA was able to alleviate the behavioral defects in the rotarod performance test and pole test, and partially rescue the significant loss of dopaminergic neurons in the substantia nigra (SN) chemically induced by MPTP in mice. Moreover, the PD + MA mice showed a tendency toward decreased intestinal microbial alpha diversity, while EA significantly reversed it. The abundance of Erysipelotrichaceae was significantly increased in PD + MA mice, and the alteration was also reversed by EA. In addition, the pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α were substantially increased in the SN of PD + MA mice, an effect that was reversed by EA.

CONCLUSION

These results suggest that EA may alleviate behavioral defects via modulation of gut microbiota and suppression of inflammation in the SN of mice with PD, which provides new insights into the pathogenesis of PD and its treatment.

Probiotics for pain of osteoarthritis; An N-of-1 trial of individual effects

OBJECTIVE

This study aimed to investigate the safety and effectiveness of probiotics in osteoarthritic pain for one individual.

METHODS

The study was an N-of-1 trial design, divided into 3 blocks of 10 weeks. Each block included one pair of randomized interventions (AB), separated by a washout period. The trial took place in a private naturopathic practice in Sydney, Australia. The participant was a 67 year old female with osteoarthritis in her lower back and right ankle. The active intervention was two daily capsules that contained Lactobacillus rhamnosus (LGG®), Saccharomyces cerevisiae (boulardii) and Bifidobacterium animalis ssp lactis. The placebo was an identical capsule that did not contain probiotics. The primary outcome was daily pain scores, measured by the participant on a Visual Analogue Scale (VAS). Secondary outcome measures included patient preference (of intervention), General Health Questionnaire (GHQ-12), Patient Specific Functional Scale (PSFS), Comprehensive Digestive Stool Analysis (CDSA) and rescue medication usage. A dependent t-test analysed mean pain scores for the last week of each intervention across the three blocks of the study.

RESULTS

The probiotic intervention was associated with lower pain scores and was the preferred intervention chosen by the participant. The mean pain score on the VAS was 4.9 ± 2.2 in the placebo condition compared to 4.0 ± 1.7 in the probiotic condition (t(20) = 2.2, p =  0.04, difference = 0.9, 95 % CI [0.04, 1.77]).

CONCLUSIONS

The reduction in pain scores associated with the probiotic intervention was small but clinically significant for this patient. A holistic view of the patient focusing on digestive integrity and function may be crucial for clinical applications of interventions such as probiotics. N-of-1 trial designs allow for the measurement of a holistic approach to an individual, which is aligned with naturopathic practice. Further trials are required to generate data to enable reliable estimation of population effects.

The food-gut axis: lactic acid bacteria and their link to food, the gut microbiome and human health

Lactic acid bacteria (LAB) are present in foods, the environment and the animal gut, although fermented foods (FFs) are recognized as the primary niche of LAB activity. Several LAB strains have been studied for their health-promoting properties and are employed as probiotics. FFs are recognized for their potential beneficial effects, which we review in this article. They are also an important source of LAB, which are ingested daily upon FF consumption. In this review, we describe the diversity of LAB and their occurrence in food as well as the gut microbiome. We discuss the opportunities to study LAB diversity and functional properties by considering the availability of both genomic and metagenomic data in public repositories, as well as the different latest computational tools for data analysis. In addition, we discuss the role of LAB as potential probiotics by reporting the prevalence of key genomic features in public genomes and by surveying the outcomes of LAB use in clinical trials involving human subjects. Finally, we highlight the need for further studies aimed at improving our knowledge of the link between LAB-fermented foods and the human gut from the perspective of health promotion.

Efeitos da suplementação com probióticos em pacientes com o vírus da imunodeficiência humana: revisão sistemática

Objetivo:  É de conhecimento que certos micro-organismos melhoram a função da barreira intestinal, que por sua vez é atingida pela infecção pelo (HIV). Esta revisão teve como objetivo identificar os possíveis efeitos da suplementação com probióticos em pacientes acometidos peloVírus da Imunodeficiência Humana (HIV). Métodos: Foram utilizadas as bases de dados do MEDLINE/PubMed e Lilacs publicados na língua inglesa, no período 2008 a 2018, com os descritores “probiotics” AND “HIV”. Foram incluídos ensaios clínicos randomizados realizados em indivíduos adultos acometidos pelo HIV, que tenham feito uso de probióticos. Foram excluídos artigos não-originais e trabalhos em outro idioma que não a língua inglesa, além de estudos com animais ou in vitro e ainda estudos em gestantes, lactentes e pessoas com idade inferior a 18 anos. Resultados: Do total de 149 artigos encontrados, 10 obedeceram aos critérios de inclusão. As principais cepas utilizadas foram do gênero Lactobacillus e Bifidobacterium. Os principais achados dos estudos estão relacionados à redução da translocação bacteriana e inflamação, aumento do número de células T CD4+ e redução do D-dímero, bem como melhora dos sintomas gastrointestinais. Conclusões: Existem evidências de que a suplementação com probióticos possa ser recomendada na prática clínica como adjuvante da terapia antiretroviral. Entretanto, em decorrência da complexidade do assunto e de os estudos nessa temática serem escassos e heterogêneos, faz-se necessários mais estudos a fim de determinar cepas, tempo de intervenção, dosagens, bem como a efetividade do uso de probióticos por pacientes com HIV.

HIV, Sexual Orientation, and Gut Microbiome Interactions

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

Challenges in the management of HIV infection: update on the role of probiotic supplementation as a possible complementary therapeutic strategy for cART treated people living with HIV/AIDS

Introduction: Recent insights show that gut-mucosal immunity and intestinal microbiota play a key role in the pathogenesis of HIV infection. Alterations in the composition of intestinal flora (dysbiosis) could be associated with an impaired intestinal epithelium barrier activity and an impaired mucosal immunity function, significantly contributing to microbial translocation which is considered a major driver of chronic immune activation. Areas covered: This article provides an overview on the novel trends in probiotic therapy application. A particular emphasis is addressed to the importance of probiotics as a novel strategy to attenuate or prevent gastrointestinal involvement and to improve gut-mucosal immunity in HIV-infected subjects. Therefore, opportunities, limits and methodological criticalities of supplementation with probiotic therapy are considered and analyzed. Expert opinion: Use of probiotics is emerging as a novel strategy to manage dysbiosis and gut-mucosal impairment, to reduce immune activation and to limit a number of non-AIDS-related disorders. However, despite the growing use of probiotic therapy, mechanisms by which oral bacteria intake exhibits its effects are strain-related and disease-specific, hence clinicians need to take these two factors into consideration when suggesting probiotic supplementation to HIV-infected patients.

HIV, Cancer, and the Microbiota: Common Pathways Influencing Different Diseases

HIV infection exerts profound and perhaps irreversible damage to the gut mucosal-associated lymphoid tissues, resulting in long-lasting changes in the signals required for the coordination of commensal colonization and in perturbations at the compositional and functional level of the gut microbiota. These abnormalities in gut microbial communities appear to affect clinical outcomes, including T-cell recovery, vaccine responses, HIV transmission, cardiovascular disease, and cancer pathogenesis. For example, the microbial signature associated with HIV infection has been shown to induce tryptophan catabolism, affect the butyrate synthesis pathway, impair anti-tumoral immunity and affect oxidative stress, which have also been linked to the pathogenesis of cancer. Furthermore, some of the taxa that are depleted in subjects with HIV have proved to modulate the anti-tumor efficacy of various chemotherapies and immunotherapeutic agents. The aim of this work is to provide a broad overview of recent advances in our knowledge of how HIV might affect the microbiota, with a focus on the pathways shared with cancer pathogenesis.

Mechanisms of Cardiovascular Disease in the Setting of HIV Infection

Although the initial reports of increased cardiovascular (CV) disease in the setting of advanced AIDS were reported approximately 30 years ago, advances in antiretroviral therapy and immediate initiation of therapy on diagnosis have transformed what was once a deadly infectious disease into a chronic health condition. Accordingly, the types of CV diseases occurring in HIV have shifted from pericardial effusions and dilated cardiomyopathy to atherosclerosis and heart failure. The underlying pathophysiology of HIV-associated CV disease remains poorly understood, partly because of the rapidly evolving nature of HIV treatment and because clinical endpoints take many years to develop. The gut plays an important role in the early pathogenesis of HIV infection as HIV preferentially infects CD4+ T cells, 80% of which are located in gut mucosa. The loss of these T cells damages gut mucosa resulting in increased gut permeability and microbial translocation, which incites chronic inflammation and immune activation. Antiretroviral therapy does not cure HIV infection and immune abnormalities persist. These abnormalities correlate with mortality and CV events. The effects of antiretroviral therapy on CV risk are complex; treatment reduces inflammation and other markers of CV risk but induces lipid abnormalities, most commonly hypertriglyceridemia. On a molecular level, monocytes/macrophages, platelet reactivity, and immune cell activation, which play a role in the general population, may be heightened in the setting of HIV and contribute to HIV-associated atherosclerosis. Chronic inflammation represents an inviting therapeutic target in HIV, as it does in uninfected persons with atherosclerosis.