The microbiota-gut-brain axis: neurobehavioral correlates, health and sociality

Recent data suggest that the human body is not such a neatly self-sufficient island after all. It is more like a super-complex ecosystem containing trillions of bacteria and other microorganisms that inhabit all our surfaces; skin, mouth, sexual organs, and specially intestines. It has recently become evident that such microbiota, specifically within the gut, can greatly influence many physiological parameters, including cognitive functions, such as learning, memory and decision making processes. Human microbiota is a diverse and dynamic ecosystem, which has evolved in a mutualistic relationship with its host. Ontogenetically, it is vertically inoculated from the mother during birth, established during the first year of life and during lifespan, horizontally transferred among relatives, mates or close community members. This micro-ecosystem serves the host by protecting it against pathogens, metabolizing complex lipids and polysaccharides that otherwise would be inaccessible nutrients, neutralizing drugs and carcinogens, modulating intestinal motility, and making visceral perception possible. It is now evident that the bidirectional signaling between the gastrointestinal tract and the brain, mainly through the vagus nerve, the so called “microbiota–gut–vagus–brain axis,” is vital for maintaining homeostasis and it may be also involved in the etiology of several metabolic and mental dysfunctions/disorders. Here we review evidence on the ability of the gut microbiota to communicate with the brain and thus modulate behavior, and also elaborate on the ethological and cultural strategies of human and non-human primates to select, transfer and eliminate microorganisms for selecting the commensal profile.

Frequent Transmission of Gonorrhea in Men Who Have Sex with Men

The rate of gonorrhea is much higher in men who have sex with men than in heterosexuals. Because of unique behavioral characteristics, asymptomatic sites of infection, mainly the pharynx, are principal drivers of gonorrhea prevalence in men who have sex with men. On the basis of this observation, we call for interventions.

Kissing may be an important and neglected risk factor for oropharyngeal gonorrhoea: a cross-sectional study in men who have sex with men

OBJECTIVES

A mathematical model suggested that a significant proportion of oropharyngeal gonorrhoea cases are acquired via oropharynx-to-oropharynx transmission (ie, tongue-kissing), but to date, no empirical study has investigated this. This study aimed to examine the association between kissing and oropharyngeal gonorrhoea among gay and bisexual men who have sex with men (MSM).

METHODS

MSM attending a public sexual health centre in Melbourne, Australia, between March 2016 and February 2017 were invited to participate in a brief survey that collected data on their number of male partners in the last 3 months, in three distinct categories: kissing-only (ie, no sex including no oral and/or anal sex), sex-only (ie, any sex without kissing), and kissing-with-sex (ie, kissing with any sex). Univariable and multivariable logistic regression analyses were performed to examine associations between oropharyngeal gonorrhoea positivity by nucleic acid amplification tests and the three distinct partner categories.

RESULTS

A total of 3677 men completed the survey and were tested for oropharyngeal gonorrhoea. Their median age was 30 (IQR 25-37) and 6.2% (n=229) had oropharyngeal gonorrhoea. Men had a mean number of 4.3 kissing-only, 1.4 sex-only, and 5.0 kissing-with-sex partners in the last 3 months. Kissing-only and kissing-with-sex were associated with oropharyngeal gonorrhoea, but sex-only was not. The adjusted odds for having oropharyngeal gonorrhoea were 1.46-fold (95% CI 1.04 to 2.06) for men with ≥4 kissing-only partners and 1.81-fold (95% CI 1.17 to 2.79) for men with ≥4 kissing-with-sex partners.

CONCLUSIONS

These data suggest that kissing may be associated with transmission of oropharyngeal gonorrhoea in MSM, irrespective of whether sex also occurs.

The role of saliva in gonorrhoea and chlamydia transmission to extragenital sites among men who have sex with men: new insights into transmission

INTRODUCTION

Gonorrhoea and chlamydia cases have been rising among gay, bisexual and other men who have sex with men (MSM) over the last decade. The majority of cases are extragenital and occur at the oropharynx and anorectum. The aim of this narrative review was to review the risk factors and mode of transmission for gonorrhoea and chlamydia at the oropharynx and anorectum among MSM.

RESULTS AND DISCUSSION

New evidence suggests that oropharyngeal gonorrhoea can be transmitted by kissing in addition to through the established route of condomless oral sex; and anorectal gonorrhoea can be acquired when saliva is used as a lubricant for anal sex and rimming in addition to the established route of condomless penile-anal sex in MSM. In contrast, condomless penile-anal sex remains the major route for chlamydia transmission.

CONCLUSIONS

Substantial transmission of gonorrhoea may occur with practices other than the established routes of condomless oral and/or anal sex and hence condoms may not be effective in preventing gonorrhoea transmission to extragenital sites. In contrast, condoms are effective for chlamydia control because it is mainly transmitted through condomless penile-anal sex. Novel interventions for gonorrhoea that reduce the risk of transmission at extragenital site are required.

Oropharyngeal Gonorrhea in Absence of Urogenital Gonorrhea in Sexual Network of Male and Female Participants, Australia, 2018

We describe a sexual network consisting of 1 nonbinary-gendered participant and 2 male and 4 female participants in Australia, 2018. Six of 7 participants had oropharyngeal gonorrhea in the absence of urogenital gonorrhea. This observation supports a new paradigm of gonorrhea transmission in which oropharyngeal gonorrhea can be transmitted through tongue kissing.

Family matters: Directionality of turning bias while kissing is modulated by context

When leaning forward to kiss to a romantic partner, individuals tend to direct their kiss to the right more often than the left. Studies have consistently demonstrated this kissing asymmetry, although other factors known to influence lateral biases, such as sex or situational context, had yet to be explored. The primary purpose of our study was to investigate if turning direction was consistent between a romantic (parent-parent) and parental (parent-child) kissing context, and secondly, to examine if sex differences influenced turning bias between parent-child kissing partners. An archival analysis coded the direction of turning bias for 161 images of romantic kissing (mothers kissing fathers) and 529 images of parental kissing (mothers or fathers kissing sons or daughters). The results indicated that the direction of turning bias differed between kissing contexts. As expected, a right-turn bias was observed for romantic kissing; however, a left-turn bias was exhibited for parental kissing. There was no significant difference of turning bias between any parent-child kissing partners. Interpretations for the left-turn bias discuss parental kissing as a learned lateral behaviour.

Kissing Stents for Superior Vena Cava Syndrome Due to Mediastinal Fibrosis

Purpose:

To report the endovascular reconstruction of the superior vena cava (SVC), innominate and internal jugular veins following stenosis due to mediastinal fibrosis.

Case Report:

A 36-year-old female with mediastinal fibrosis was referred for symptomatic SVC syndrome (SVCS). A covered stent was inserted in the SVC with 2 kissing stents in the innominate and jugular veins via anterograde right femoral vein access with sandwich technique. She exhibited near-immediate relief of debilitating symptoms. Computed tomographic scan demonstrated patent vessels at 1 year.

Conclusions:

Extensive endovascular venous reconstruction is an effective treatment for SVCS due to mediastinal fibrosis.

Changes in Diverse Sexual and Contraceptive Behaviors Across College

Researchers have made repeated calls for a better understanding of normative sexuality development during adolescence and young adulthood. We examined how the occurrence of seven penetrative, nonpenetrative, and contraceptive behaviors changed longitudinally across seven waves, and how individual (gender) and contextual (romantic relationship status) factors related to these changes in a sample of college students (N = 730, M age = 18.4 at Semester 1; 51% female; 26% Hispanic/Latino American, 22% Black/African American, 30% Asian American/Pacific Islander, 45% White/European American). Across college, reported kissing, touching, performing and receiving oral sex, and penetrative sex rates increased, and contraception use (any type) and condom use (in particular) rates decreased, demonstrating changes with age independent of young adults' romantic relationship experiences. Rates of all sexual behaviors were higher, and of contraception use lower, when students were in serious romantic relationships. Contraception use decreased more for men than for women, particularly in semesters men were not in serious relationships. Condom use decreased for men, and for women in semesters they were in serious relationships. Findings demonstrate normative trends in sexuality development, as well as suggesting the value of enhanced sexual health promotion programming, with a particular focus on contraceptive behaviors, across college.

Commensal Neisseria Are Shared between Sexual Partners: Implications for Gonococcal and Meningococcal Antimicrobial Resistance

Antimicrobial resistance in pathogenic Neisseria parallels reduced antimicrobial susceptibility in commensal Neisseria in certain populations, like men who have sex with men (MSM). Although this reduced susceptibility can be a consequence of frequent antimicrobial exposure at the individual level, we hypothesized that commensal Neisseria are transmitted between sexual partners. We used data from a 2014 microbiome study in which saliva and tongue swabs were taken from 21 couples (42 individuals). Samples were analyzed using 16S rRNA gene sequencing. We compared intimate partners with unrelated individuals and found that the oral Neisseria communities of intimate partners were more similar than those of unrelated individuals (average Morisita-Horn dissimilarity index for saliva samples: 0.54 versus 0.71, respectively (p = 0.005); and for tongue swabs: 0.42 versus 0.63, respectively (p = 0.006)). This similarity presumably results from transmission of oral Neisseria through intimate kissing. This finding suggests that intensive gonorrhea screening in MSM may, via increased antimicrobial exposure, promote, rather than prevent, the emergence and spread of antimicrobial resistance in Neisseria. Non-antibiotic strategies such as vaccines and oral antiseptics could prove more sustainable options to reduce gonococcal prevalence.

Intimate Contact Could Be Dangerous for Your Health

PURPOSE

To review evidence of hypersensitivity reactions to allergens and/or pathogens transmitted via intimate contact.

METHODS

We reviewed PubMed for publications in English between 1980 and 2018 using the terms allergy, drugs, foods, hypersensitivity, intercourse, kissing, Kounis syndrome, mast cells, and semen.

FINDINGS

In human RELATIONSHIPS, intimate contact can occasionally have disastrous or even fatal consequences because antigens and pathogens can be transmitted via the oral and vaginal mucosa. Hypersensitivity to semen is an underrecognized problem. Some individuals also developed acute coronary hypersensitivity, which mimics myocardial infarction, known as Kounis syndrome.

IMPLICATIONS

Hypersensitivity reactions to allergens and/or pathogens via intimate contact are common and should be recognized. Sensitive patients should be evaluated for atopic diathesis because such patients may be more susceptible and could also develop Kounis syndrome.

Duration of kissing in different intimate positions among men who have sex with men: A cross-sectional study

BackgroundDespite mounting evidence showing that kissing (tongue-kissing) may transmit gonorrhoea between men who have sex with men (MSM), little data exists on factors influencing the duration of kissing while they are above and/or lying underneath a partner for this population group.MethodsBetween May 2019 and March 2020, we invited MSM aged ≥18 years who attended the Melbourne Sexual Health Centre (MSHC) to participate in a survey about the duration of their kissing (minutes) and intimate position while kissing (i.e., kissing while above, or while lying underneath) their most recent partner. Univariable and multivariable negative binomial regressions were performed to examine the associations between the duration of kissing in different intimate positions, and demographic and behavioural characteristics (including age, region of birth, HIV status or PrEP use, and role in anal sex).ResultsOf the 965 men with a recent male kissing partner, 89.0% (n = 859) also had sex with that partner. Of the 166 men with a recent female kissing partner, 71.7% (n = 119) also had sex with that partner. Our adjusted analyses showed that, on average, men born in Asia (mean 8.52 vs 11.69 min, p < .001) and South America or the Caribbean (mean 8.61 vs 11.69 min, p = .022) spent less time kissing compared to men born in Oceania, and the same was also observed for kissing while above or lying underneath. Men who had only receptive anal sex spent less time kissing while above than those who only had insertive anal sex (mean 3.04 vs 5.86 min, p < .001).ConclusionOur study is the first to examine factors that influence duration of kissing in different intimate positions. These factors could be associated with oropharyngeal gonorrhoea if saliva transmitted gonorrhoea and if gravity played a role.

The evolutionary origin of human kissing

A kiss has been a signal of special affection across continents and cultures for millennia. Between times and peoples, social norms invariably prescribe kissing to specific affiliations and contexts, implying deeper biological bases. Why the protruding of the lips and slight suction when touching another? Capuchin monkeys stick their fingers in their friends' eyes as sign of affection, why have humans developed kissing? Here I briefly review proposed hypotheses for the evolution of human kissing. Great ape social behavior suggests that kissing is likely the conserved final mouth-contact stage of a grooming bout when the groomer sucks with protruded lips the fur or skin of the groomed to latch on debris or a parasite. The hygienic relevance of grooming decreased over human evolution due to fur-loss, but shorter sessions would have predictably retained a final "kissing" stage, ultimately, remaining the only vestige of a once ritualistic behavior for signaling and strengthening social and kinship ties in an ancestral ape.

Artistic turns: laterality in paintings of kisses and embraces

Many lateral biases exist in human behavior, often implicit and not deliberated. Romantic kissing and embracing received experimental attention in the last three decades. We investigated laterality in paintings depicting these social interactions using two methodologies to assess whether painters depicted such biases and whether these biases could be due to observers' aesthetic preferences or painters' ability in portraying naturalistic interactions. In Study 1, we inspected about 190,000 artworks available online to classify leftward and rightward biases in romantic kisses and embraces. The comparison of 103 paintings depicting clearly lateralized interactions revealed a significant rightward bias in romantic kissing (66%) and a trend toward a leftward bias (62%) for embraces, aligning with naturalistic studies of human interactions. In Study 2, 128 participants expressed their aesthetic preference between the paintings selected in Study 1 and their vertically mirrored versions. A preference for the original paintings over their mirrored versions emerged, especially when presented in the upper portion of the screen, but no significant preference for the typical lateralization of kissing and embracing was found. These findings suggest that artists' alignment with naturalistic biases could be due to familiarity and exposure to asymmetric interactions rather than observers' aesthetic preferences.

The Degree of Stent Apposition Measured by Stent Enhancement at the Level of the Side Branch as a Novel Predictor of Procedural Success in Left Main PCI

BACKGROUND

Stent enhancement techniques allow adequate visualization of stent deformation or incomplete stent expansion at the ostium of the side branch. Measuring the stent enhancement side branch length (SESBL) could reflect procedural success in terms of optimal stent expansion and apposition with better long-term outcomes. A longer SESBL may reflect a better stent apposition at the polygon of confluence and at the side branch (SB) ostium.

METHODS

We evaluated 162 patients receiving the left main (LM) provisional one-stent technique and measured the SESBL, dividing them into two groups: SESBL≤ 2.0 mm and SESBL > 2.0 mm.

RESULTS

The mean SESBL was 2.0 ± 1.2 mm. More than half of the bifurcations had both main and side branch lesions (Medina 1-1-1) (84 patients, 51.9%) and the length of the SB disease was 5.2 ±1.8 mm. Kissing balloon inflation (KBI) was performed in 49 patients (30.2%). During follow-up (12 months), there was a significantly higher rate of cardiac death in the SESBL ≤ 2.0 mm group (p = 0.02) but no significant difference in all major adverse cardiovascular events (MACEs) (p = 0.7). KBI did not influence the outcomes (p = 0.3).

CONCLUSION

Suboptimal SESBL is positively correlated with worse outcomes and SB compromise. This novel sign could aid the LM operator to assess the level of stent expansion at the ostium of the SB in the absence of intracoronary imaging.

The Survival of the Kiss: Presence and Persistence of Salivary Male DNA in Mixed Samples

BACKGROUND/OBJECTIVES

The study of DNA transfer and persistence has become increasingly significant, driven by advancements in DNA detection sensitivity and the need for reliable forensic evidence. In forensic investigations, saliva and saliva-stained materials are recognised as valuable DNA sources, particularly in cases of homicide, sexual assault, and burglary, where saliva can be transferred between individuals during the criminal act. The time between the crime and sample collection is a critical factor that can influence the success of the analysis. The value of the specimens collected from the victim's skin or mouth (perilabial and labial sites, teeth and tongue) after the crime has not been investigated with currently used highly sensitive and specific molecular methods.

METHODS

On the assumption that a significant loss of DNA occurred, in our study, 10 voluntary pairs were tested at different time points after intense kissing and samples were taken from the above-mentioned sites to assess the presence of the donor's DNA. Extracted DNA was quantified using the Plexor HY System kit (Promega), and both autosomal STRs and Y-STRs were analysed.

RESULTS

The results reveal a greater persistence of male DNA on the female partner, particularly in the labial and perilabial regions, even up to 120 min after contact, in terms of both concentration and duration.

CONCLUSIONS

This study emphasises the forensic importance of salivary DNA as a solid source of evidence, particularly in investigations involving mixed DNA profiles.