Relationship between gut microbiota, probiotics, and type 2 diabetes mellitus.

The worldwide prevalence of type 2 diabetes mellitus (T2DM) is constantly increasing, and it has become a major concern, with several implications for public health, economy, and social well-being. It is well-known that several factors such as lifestyle, increased intake of fat and sugar-rich foods, and host genetics can lead to T2DM. Some recent studies have suggested that the composition of the intestinal microbiota can trigger T2DM. Since then, considerable effort has been made to understand the link between the composition of intestinal microbiota and T2DM, as well as the role of probiotics in modulation of intestinal microbiota. This mini-review summarizes the major findings and discusses the close relationship between intestinal microbiota, probiotics, and T2DM.

In vitro modulation of human gut microbiota composition and metabolites by Bifidobacterium longum BB-46 and a citric pectin.

The gut microbiota composition and its metabolites have high impact on human health. Exploitation of prebiotics and probiotics for modulation of gut microbiota can lead to promising outcomes. This study aimed to evaluate the effects of the probiotic strain Bifidobacterium longum BB-46 alone and in combination with a citric pectin from lemon on the gut microbiota from healthy adults using the Simulator of Human Intestinal Microbial Ecosystem (SHIME®). Changes in microbiota composition and in metabolic activity were assessed by the 16S rRNA gene sequencing and by analyses of short-chain fatty acids (SCFAs) and ammonium ions (NH4+). An increase in the relative abundances of Firmicutes (especially the members of Lachnospiraceae and Lactobacillaceae families) and Bacteroidetes was observed during treatment with B. longum BB-46 alone in all compartments of the colon. Treatment with B. longum BB-46 and pectin stimulated an increase in the proportions of genera Faecalibacterium, Eubacterium and Lactobacillus, as well as in the Ruminococcaceae family in the transverse and descending colons. Concurrently, the butyrate levels increased in these two compartments. Additionally, the combination of B. longum BB-46 and pectin reduced the abundance of proteolytic bacteria Bacteroides, Clostridium, Peptoniphilus, and Streptococcus, along with decreased NH4+ production. No significant changes could be observed on NH4+ production by treatment with B. longum BB-46, nor did it increase the amount of SCFAs. In this study, we observed that although each treatment was able to modulate the microbiota, the combination of B. longum BB-46 and pectin was more efficient in decreasing the intestinal NH4+ levels and in increasing butyric acid-producing bacteria. These findings indicate that B. longum BB-46, especially when combined with the specific citric pectin, might have beneficial impact on human health.

In vitro colonic fermentation of Mexican "taco" from corn-tortilla and black beans in a Simulator of Human Microbial Ecosystem (SHIME®) system.

A Mexican staple food prepared with corn "tortilla" (Zea mays L.) and common beans (Phaseolus vulgaris L.) is named as "taco". It was fermented in an in vitro colonic Simulator of Human Microbial Ecosystem (SHIME®) to evaluate the effect in short chain fatty acids (SCFA), ammonia production, and the growth of total presumptive counts for anaerobic bacteria, Lactobacillus spp., Bifidobacterium spp., Clostridium spp., and total coliforms in the three simulated reactors of the human colon. After two weeks of stabilization, the simulator was fed during 9 days with the mixture of 50 g of beans and 50 g of tortilla mixed with 100 mL of carbohydrate based medium. Every third day, samples were collected from the three simulated colon vessels for the corresponding analysis. The production of the SCFA was higher during the treatment period than the basal period in the three colon sections. The acetate was produced in higher concentration (191.9 mmol/L) than propionate and butyrate (29.1 and 55.0 mmol). During the treatment period, the higher molar ratio (%) for acetate, propionate, and butyrate were 84: 14: 24, respectively. The ammonia ions as well as the growth of presumptive coliforms were reduced (p < 0.05) in the three simulated colon vessels during the treatment. Finally, in vitro fermentation of Mexican "taco" showed a possible potential functional profile of an ancestral staple food due to the production of SCFA that may exert beneficial effects.

Impact of combining acerola by-product with a probiotic strain on a gut microbiome model.

In this study, we first investigated the survival of three probiotic strains, individually and combined with acerola by-product during simulated gastrointestinal conditions. Next, we investigated the effects of acerola by-product combined with Bifidobacterium longum BB-46 on a gut microbiota model (SHIME®). Chemical composition, total phenolic compounds, antioxidant activity of the acerola by-product and microbial counts, denaturing gradient gel electrophoresis (DGGE), ammonium ions ( NH4+ ) and short-chain fatty acids (SCFAs) analysis of the SHIME® samples were performed. Acerola by-product revealed high protein and fibre, reduced lipid contents, and showed to be an excellent source of total phenolic compounds with high in vitro antioxidant activity. A decreased amount of NH4+ in the ascending colon and an increase (p < .05) in SCFAs were observed in the three regions of colon during treatment with BB-46 and acerola by-product. BB-46 combined with acerola by-product showed positive effects on the gut microbiota metabolism in SHIME® model.

Gut microbiome approaches to treat obesity in humans.

The rising worldwide prevalence of obesity has become a major concern having many implications for the public health and the economy. It is well known that many factors such as lifestyle, increased intake of foods high in fat and sugar and a host's genetic profile can lead to obesity. Besides these factors, recent studies have pointed to the gut microbiota composition as being responsible for the development of obesity. Since then, many efforts have been made to understand the link between the gut microbiota composition and obesity, as well as the role of food ingredients, such as pro- and prebiotics, in the modulation of the gut microbiota. Studies involving the gut microbiota composition of obese individuals are however still controversial, making it difficult to treat obesity. In this sense, this mini-review deals with obesity and the relationship with gut microbiota, summarising the principal findings on gut microbiome approaches for treating obesity in humans.

Modulation of gut microbiota from obese individuals by in vitro fermentation of citrus pectin in combination with Bifidobacterium longum BB-46.

This study aimed to evaluate the effects of three treatments, i.e., Bifidobacterium longum BB-46 (T1), B. longum BB-46 combined with the pectin (T2), and harsh extracted pectin from lemon (T3) on obesity-related microbiota using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). The effects of the treatments were assessed by the analysis of the intestinal microbial composition (using 16S rRNA gene amplicon sequencing) and the levels of short-chain fatty acids (SCFAs) and ammonium ions (NH4+). Treatments T2 and T3 stimulated members of the Ruminococcaceae and Succinivibrionaceae families, which were positively correlated with an increase in butyric and acetic acids. Proteolytic bacteria were reduced by the two treatments, concurrently with a decrease in NH4+. Treatment T1 stimulated the production of butyric acid in the simulated transverse and descending colon, reduction of NH4+ as well as the growth of genera Lactobacillus, Megamonas, and members of Lachnospiracea. The results indicate that both B. longum BB-46 and pectin can modulate the obesity-related microbiota; however, when the pectin is combined with B. longum BB-46, the predominant effect of the pectin can be observed. This study showed that the citric pectin is able to stimulate butyrate-producing bacteria as well as genera related with anti-inflammatory effects. However, prospective clinical studies are necessary to evaluate the anti/pro-obesogenic and inflammatory effects of this pectin for future prevention of obesity.

HIV Prevalence and Awareness of Positive Serostatus Among Men Who Have Sex With Men and Transgender Women in Bogotá, Colombia.

OBJECTIVES: We estimated HIV prevalence among men who have sex with men (MSM) and transgender women in Bogotá, Colombia, and explored differences between HIV-positive individuals who are aware and unaware of their serostatus. METHODS: In this cross-sectional 2011 study, we used respondent-driven sampling (RDS) to recruit 1000 MSM and transgender women, who completed a computerized questionnaire and received an HIV test. RESULTS: The RDS-adjusted prevalence was 12.1% (95% confidence interval [CI] = 8.7, 15.8), comparable to a previous RDS-derived estimate. Among HIV-positive participants, 39.7% (95% CI = 25.0, 54.8) were aware of their serostatus and 60.3% (95% CI = 45.2, 75.5) were unaware before this study. HIV-positive-unaware individuals were more likely to report inadequate insurance coverage, exchange sex (i.e., sexual intercourse in exchange for money, goods, or services), and substance use than other participants. HIV-positive-aware participants were least likely to have had condomless anal intercourse in the previous 3 months. Regardless of awareness, HIV-positive participants reported more violence and forced relocation experiences than HIV-negative participants. CONCLUSIONS: There is an urgent need to increase HIV detection among MSM and transgender women in Bogotá. HIV-positive-unaware group characteristics suggest an important role for structural, social, and individual interventions.

Gender Affirmation and Body Modification Among Transgender Persons in Bogotá, Colombia.

This paper examined structural, social, and personal characteristics that shape the processes of gender affirmation and body modification among transgender persons (assigned male at birth) in Bogotá, Colombia. Qualitative data from life-history interviews (N=14) and a focus group (N=11) explored research questions concerning the ways in which the internal psychological and external contextual processes influence individuals' decisions and behaviors concerning hormonal treatment, injections, or surgery. Research questions concerning practices and consequences of treatment performed without medical supervision were addressed through qualitative data, as well as quantitative data from 58 transgender participants. Findings indicated variation in ways participants conceptualized gender (e.g., binary or fluid), but an increased feminine presentation was a strong personal desire expressed by many and often encouraged by romantic partners and transgender friends. Transgender individuals within participants' social networks were frequently instrumental not only in providing information about hormones and contouring injections, but also in carrying out procedures-sometimes with negative consequences. Body modification procedures occurred primarily outside the health care system, due to limited access to or awareness of medical care, societal stigma, social norms within the transgender community, and personal decision-making. Public health approaches to protect the health of transgender persons undergoing body modification were suggested.

HIV testing among MSM in Bogotá, Colombia: the role of structural and individual characteristics.

This study used mixed methods to examine characteristics related to HIV testing among men who have sex with men (MSM) in Bogotá, Colombia. A sample of 890 MSM responded to a computerized quantitative survey. Follow-up qualitative data included 20 in-depth interviews with MSM and 12 key informant interviews. Hierarchical logistic set regression indicated that sequential sets of variables reflecting demographic characteristics, insurance coverage, risk appraisal, and social context each added to the explanation of HIV testing. Follow-up logistic regression showed that individuals who were older, had higher income, paid for their own insurance, had had a sexually transmitted infection, knew more people living with HIV, and had greater social support were more likely to have been tested for HIV at least once. Qualitative findings provided details of personal and structural barriers to testing, as well as inter-relationships among these factors. Recommendations to increase HIV testing among Colombian MSM are offered.

Sex work among men who have sex with men and transgender women in Bogotá.

This qualitative study examined sex work among internally displaced male and transgender female sex workers in Bogotá, Colombia. Internal displacement has occurred in Colombia as a result of decades of conflict among armed groups and has created large-scale migration from rural to urban areas. Informed by the polymorphous model of sex work, which posits that contextual conditions shape the experience of sex work, we examined three main research questions. The first dealt with how internal displacement was related to the initiation of sex work; the second concerned the effect of agency on sex worker satisfaction; and the third examined how sex work in this context was related to HIV and other risks. Life history interviews were conducted with 26 displaced individuals who had done sex work: 14 were men who have sex with men and 12 were transgender women (natal males). Findings revealed that many participants began doing sex work in the period immediately after displacement, because of a lack of money, housing, and social support. HIV risk was greater during this time due to limited knowledge of HIV and inexperience negotiating safer sex with clients. Other findings indicated that sex workers who exerted more control and choice in the circumstances of their work reported greater satisfaction. In addition, we found that although many sex workers insisted on condom use with clients, several noted that they would sometimes have unprotected sex for additional money. Specific characteristics affecting the experience of sex work among the transgender women were also discussed.

Beneficial effects of fermented vegetal beverages on human gastrointestinal microbial ecosystem in a simulator.

The aim of this study was to evaluate the effects of four beverage formulations (prebiotic - fructooligosaccharide, probiotic - Lactobacillus casei Lc-01, synbiotic - fructooligosaccharide and L. casei Lc-01 and placebo) based on aqueous extracts of soy and quinoa, towards the human intestinal microbiota using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), a dynamic model of the human gut. To monitor the effects on microbial community composition, plate counts on specific growth media and a PCR-DGGE analysis were performed on samples from all colon compartments - ascending, transverse and descending. To verify the effects on microbial metabolism, we analyzed the ammonium and short chain fatty acids (SCFAs) concentrations. The synbiotic beverage showed the best microbiological results in the ascending colon compartment, stimulating the growth of Lactobacillus spp. and Bifidobacterium spp., and reducing Clostridium spp., Bacteroides spp., enterobacteria and Enterococcus spp. populations in this compartment. A larger reduction (p<0.05) of ammonia ions in the ascending colon was observed during the synbiotic beverage treatment. No statistical difference was observed in SCFA production among the treatments and the basal period. Plate count and DGGE analysis showed the survival of L. casei Lc-01 in the colon. DGGE analysis also showed higher richness and diversity of the Lactobacillus spp. community during the treatment with synbiotic beverage, with higher accentuation in the ascending colon.

Can additive measures add to an intersectional understanding? Experiences of gay and ethnic discrimination among HIV-positive Latino gay men.

The current study investigated a methodological question of whether traditional, additive, quantitative data can be used to address intersectional issues, and illustrated such an approach with a sample of 301 HIV-positive, Latino gay men in the United States. Participants were surveyed using A-CASI. Hierarchical logistic set regression investigated the role of sets of variables reflecting demographic characteristics, gender nonconformity, and gay and ethnic discrimination in relation to depression and gay collective identity. Results showed the discrimination set was related to depression and to gay collective identity, as was gender nonconformity. Follow-up logistic regression showed that both types of discrimination were associated with greater depression, but gender nonconformity was not. Gay discrimination and gender nonconformity were positively associated with gay collective identity, whereas ethnic discrimination was negatively associated. Results are discussed in terms of the use of traditional quantitative data as a potential means of understanding intersectional issues, as well as of contributing to knowledge about individuals facing multiple structural inequalities.

Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.

Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogotá, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogotá. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied.

Sex with sex workers among latino day laborers in Suburban Maryland.

Using the structural-environmental conceptual framework, this study employed mixed methods to address the question of whether sex with female sex workers contributes to HIV risk among male immigrant Latino day laborers in suburban Maryland. Because contextual factors can greatly affect HIV risk for both sex workers and their clients, this study investigated the organizational structure of sex work, factors that predicted men's hiring of sex workers, sexual behaviors performed with sex workers, and the use of condoms. Qualitative research was conducted to inform the development of a quantitative survey, but also provided crucial descriptions about the motivations, locations, arrangements, and sexual activities related to sex work. Key informant interviews (N = 10), in-depth interviews with day laborers (N = 10) and Latina female sex workers (N = 4), and two focus groups with day laborers (N = 11) were conducted, and a quantitative survey administered via Audio-enhanced Computer-assisted Self-interviewing (N = 174). Condom use was nearly universal in encounters with female sex workers, thus indicating that the sex workers were not an important source of HIV transmission in this context. Logistic regression was performed to test a model predicting sex with sex workers. Latino day laborers who reported more immigrant stress and who did not have a partner in the U.S. were more likely to have had sex with a sex worker, as were men who reported binge drinking. Structural and social conditions influenced the hiring of sex workers. Further research is warranted to better understand the interrelationships among these circumstances and to inform the development of programs to address them.

Popular perceptions of circumcision among Colombian men who have sex with men.

Male circumcision has received increased attention for its potential to reduce sexual transmission of HIV. Research on the acceptability of circumcision as a means of HIV prevention among men who have sex with men is limited. Men who have sex with men in Bogotá, Colombia, either participated in a focus group in which they shared information regarding their perceptions of circumcision or completed a survey that assessed circumcision experiences, attitudes, beliefs and willingness. Few participants reported they were circumcised, yet most participants reported knowing something about the procedure. Overall, attitudes towards circumcision were mixed: although circumcision was viewed as safe, it was also viewed as unnatural and cruel to babies. Beliefs that circumcision could improve sexual functioning and protect against STIs and HIV were not widely endorsed by survey participants, although focus-group participants discussed the potential impacts of circumcision on the availability of sexual partners and sexual performance. Some focus-group participants and many survey participants reported a hypothetical willingness to get circumcised if strong evidence of its effectiveness could be provided, barriers removed and recovery time minimised.

The pleasure principle: the effect of perceived pleasure loss associated with condoms on unprotected anal intercourse among immigrant Latino men who have sex with men.

Sexual pleasure has been identified as an important consideration in decision-making surrounding condom use. We examined the impact of perceived pleasure loss associated with condom use on recent history of insertive and receptive unprotected anal intercourse (UAI) among Latino men who have sex with men (MSM) living in the United States. A total of 482 Dominican, Colombian, and Brazilian immigrant MSM were surveyed regarding sexual attitudes and practices via computer-assisted self-interviewing technology with audio enhancement (ACASI). Participants rated the pleasure they derived from protected and unprotected anal intercourse in each position (insertive and receptive) and also reported their HIV status, relationship status, and recent sexual history. Men who had engaged in both positions, with and without condoms (n=268), perceived a greater pleasure loss associated with condoms during anal intercourse in the insertive versus receptive position. Logistic regression analyses controlling for HIV status, relationship status, and age revealed that men who perceived greater pleasure loss from condoms were more likely to have engaged in UAI over the past 3 months (n[insertive]=297; n[receptive]=284). Findings indicate that the pleasure loss associated with condoms may be a key deterrent for their use in either sex position among Latino MSM. Therefore, pleasure needs to be prioritized in the development of condoms and other sexual safety measures as well as in the promotion of their use.

Present and past influences on current smoking among HIV-positive male veterans.

INTRODUCTION: Cigarette smoking has become an important influence of morbidity and mortality for HIV-positive individuals in the era of highly active antiretroviral therapy. Although smoking is common among military personnel and veterans, the lasting impact of military service on smoking at a later stage of life has not been examined. The current study investigated present and past influences on current smoking among HIV-positive male veterans. METHODS: Participants were 200 HIV-positive men served by the Veterans Affairs Medical Center. A survey was administered via audio-enhanced computer-assisted self-interview, and additional information was extracted from the computerized patient record system. RESULTS: Logistic regression was performed to test hypotheses concerning the participants' current situations as well as characteristics of their past military service. Having smokers in one's environment, being more depressed, and having used alcohol or drugs were associated with having smoked in the previous 30 days, whereas stronger endorsement of attitudes stating adverse effects of smoking was linked to lower likelihood of smoking. Neither having been in a military conflict nor the length of the military service was significantly related to current smoking. CONCLUSIONS: Remote experiences in the military did not have a sustained effect on smoking behavior years later. Implications of this study for the development of smoking cessation programs targeting HIV-positive veterans include the importance of altering attitudes about tobacco, treating underlying depression, addressing social influence, decreasing substance use, and increasing awareness of the heightened vulnerability to a variety of negative consequences of smoking among infected individuals.

Characteristics of Latino MSM who have sex in public settings.

Many men who have sex with men (MSM) have sexual encounters in public places, and some data suggest that this behavior is more common among Latino than non-Hispanic white MSM in the USA. In a sample of 482 Latino MSM born in Brazil, Colombia, and the Dominican Republic, and living in the New York City metropolitan area, we examined how demographic and psychosocial characteristics are related to having sex in public venues. Logistic regression was performed with the dichotomous outcome of sex in a public place in the previous six months. Demographic variables included education, HIV-positive serostatus, unknown HIV serostatus, and years in the USA; psychosocial variables included self-efficacy for safer sex, depression, and gay community involvement. Results indicated that those individuals with unknown serostatus were more likely than those with HIV-negative serostatus to have had sex in a public setting, as were men with lower self-efficacy for safer sex. These findings suggest that the partner pool may pose some risk to men who have sex in public sex venues, and therefore, low-risk sexual practices and condom use should be promoted in such settings. Contrary to expectations, higher education was related to sex in public settings, but neither depression nor more recent immigration was. Greater involvement in the gay community was also associated with having sex in public places, which may reflect the larger social function served by gay venues such as bathhouses and bars.

Cultural beliefs, partner characteristics, communication, and sexual risk among Latino MSM.

This study examined factors associated with communication about condom use and unprotected anal intercourse (UAI) in a U.S. sample of immigrant Latino MSM (N = 356), with a focus on culturally based beliefs. Logistic regression analysis revealed that communication about condom use at participants' most recent encounter was associated with a lower likelihood of UAI during that encounter. UAI was more likely when the partner was a main partner and there was seroconcordance. A separate logistic regression indicated that communication about condom use was less likely when the most recent encounter involved a main partner, greater sexual desire, and intoxication due to substance use. Although cultural beliefs were not predictive of communication about condom use or UAI at the most recent encounter, they were related to the occurrence of UAI in the previous three months. There is a need for more research on the interplay of culture, safer sex communication, and sexual risk.

Latino gay and bisexual men's relationships with non-gay-identified men who have sex with men.

This study investigated relationships between Latino gay-identified men in metropolitan New York City and their non-gay-identified male partners. Phase 1 consisted of in-depth interviews (N = 33), and Phase 2 consisted of quantitative surveys (N = 120) with Brazilian, Colombian, and Dominican men who have sex with men (MSM). A majority of participants reported having had sex with heterosexually identified men, and in many cases, the relationship was sustained over time. We found mixed results concerning an attitude sometimes attributed to Latinos that sexual orientation is defined by sexual role, with receptive MSM seen as gay and insertive MSM seen as straight. Although there were no significant associations between partner sexual orientation and unprotected anal intercourse, gay men were less likely to take the insertive role in oral or anal sex with straight-identified male partners than with gay partners.