Quantifying variation across 16S rRNA gene sequencing runs in human microbiome studies.

Recent microbiome research has incorporated a higher number of samples through more participants in a study, longitudinal studies, and metanalysis between studies. Physical limitations in a sequencing machine can result in samples spread across sequencing runs. Here we present the results of sequencing nearly 1000 16S rRNA gene sequences in fecal (stabilized and swab) and oral (swab) samples from multiple human microbiome studies and positive controls that were conducted with identical standard operating procedures. Sequencing was performed in the same center across 18 different runs. The simplified mock community showed limitations in accuracy, while precision (e.g., technical variation) was robust for the mock community and actual human positive control samples. Technical variation was the lowest for stabilized fecal samples, followed by fecal swab samples, and then oral swab samples. The order of technical variation stability was inverse of DNA concentrations (e.g., highest in stabilized fecal samples), highlighting the importance of DNA concentration in reproducibility and urging caution when analyzing low biomass samples. Coefficients of variation at the genus level also followed the same trend for lower variation with higher DNA concentrations. Technical variation across both sample types and the two human sampling locations was significantly less than the observed biological variation. Overall, this research providing comparisons between technical and biological variation, highlights the importance of using positive controls, and provides semi-quantified data to better understand variation introduced by sequencing runs. KEY POINTS: • Mock community and positive control accuracy were lower than precision. • Samples with lower DNA concentration had increased technical variation across sequencing runs. • Biological variation was significantly higher than technical variation due to sequencing runs.

High-fat diet, microbiome-gut-brain axis signaling, and anxiety-like behavior in male rats.

Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response. Here we conducted a nine-week HFD protocol in male rats, followed by an analysis of the gut microbiome diversity and community composition, brainstem serotonergic gene expression (tph2, htr1a, and slc6a4), and anxiety-related defensive behavioral responses. We show that HFD intake decreased alpha diversity and altered the community composition of the gut microbiome in association with obesity, increased brainstem tph2, htr1a and slc6a4 mRNA expression, including in the caudal part of the dorsomedial dorsal raphe nucleus (cDRD), a subregion previously associated with stress- and anxiety-related behavioral responses, and, finally, increased anxiety-related defensive behavioral responses. The HFD increased the Firmicutes/Bacteroidetes ratio relative to control diet, as well as higher relative abundances of Blautia, and decreases in Prevotella. We found that tph2, htr1a and slc6a4 mRNA expression were increased in subregions of the dorsal raphe nucleus in the HFD, relative to control diet. Specific bacterial taxa were associated with increased serotonergic gene expression in the cDRD. Thus, we propose that HFD-induced obesity is associated with altered microbiome-gut-serotonergic brain axis signaling, leading to increased anxiety-related defensive behavioral responses in rats.

Feasibility and acceptability of an integrated mind-body intervention for depression: whole-body hyperthermia (WBH) and cognitive behavioral therapy (CBT).

OBJECTIVE: To examine the feasibility of an integrated mind-body MDD treatment combining cognitive behavioral therapy (CBT) and whole-body hyperthermia (WBH). METHODS: In this single-arm trial, 16 adults with MDD initially received 8 weekly CBT sessions and 8 weekly WBH sessions. Outcomes included WBH sessions completed (primary), self-report depression assessments completed (secondary), and pre-post intervention changes in depression symptoms (secondary). We also explored changes in mood and cognitive processes and assessed changes in mood as predictors of overall treatment response. RESULTS: Thirteen participants (81.3%) completed ≥ 4 WBH sessions (primary outcome); midway through the trial, we reduced from 8 weekly to 4 bi-weekly WBH sessions to increase feasibility. The n = 12 participants who attended the final assessment visit completed 100% of administered self-report depression assessments; all enrolled participants (n = 16) completed 89% of these assessments. Among the n = 12 who attended the final assessment visit, the average pre-post-intervention BDI-II reduction was 15.8 points (95% CI: -22.0, -9.70), p = 0.0001, with 11 no longer meeting MDD criteria (secondary outcomes). Pre-post intervention improvements in negative automatic thinking, but not cognitive flexibility, achieved statistical significance. Improved mood from pre-post the initial WBH session predicted pre-post treatment BDI-II change (36.2%; rho = 0.60, p = 0.038); mood changes pre-post the first CBT session did not. LIMITATIONS: Small sample size and single-arm design limit generalizability. CONCLUSION: An integrated mind-body intervention comprising weekly CBT sessions and bi-weekly WBH sessions was feasible. Results warrant future larger controlled clinical trials.Clinivaltrials.gov Registration: NCT05708976.

The antidepressant effect of whole-body hyperthermia is associated with the classical interleukin-6 signaling pathway.

There is urgent need for novel antidepressant treatments that confer therapeutic benefits via engagement with identified mechanistic targets. The objective of the study was to determine whether activation of the classical anti-inflammatory interleukin-6 signaling pathways is associated with the antidepressant effects of whole-body hyperthermia. A 6-week, randomized, double-blind study compared whole-body hyperthermia with a sham condition in a university-based medical center. Medically healthy participants aged 18-65 years who met criteria for major depressive disorder, were free of psychotropic medication use, and had a baseline 17-item Hamilton Depression Rating Scale score ≥ 16 were randomized with 1-to-1 allocation in blocks of 6 to receive whole-body hyperthermia or sham. Of 338 individuals screened, 34 were randomized, 30 received interventions and 26 had ≥ 2 blood draws and depressive symptom assessments. Secondary data analysis examined change in the ratio of IL-6:soluble IL-6 receptor pre-intervention, post-intervention, and at weeks 1 and 4. Hierarchical linear modeling tested whether increased IL-6:soluble IL-6 receptor ratio post-intervention was associated with decreased depressive symptom at weeks 1, 2, 4 and 6 for those randomized to whole-body hyperthermia. Twenty-six individuals were randomized to whole-body hyperthermia [n = 12; 75 % female; age = 37.9 years (SD = 15.3) or sham [n = 14; 57.1 % female; age = 41.1 years (SD = 12.5). When compared to the sham condition, active whole-body hyperthermia only increased the IL-6:soluble IL-6 receptor ratio post-treatment [F(3,72) = 11.73,p < .001], but not pre-intervention or at weeks 1 and 4. Using hierarchical linear modeling, increased IL-6:sIL-6R ratio following whole-body hyperthermia moderated depressive symptoms at weeks 1, 2, 4 and 6, such that increases in the IL-6:soluble IL-6 receptor ratio were associated with decreased depressive symptoms at weeks 1, 2, 4 and 6 for those receiving the active whole-body hyperthermia compared to sham treatment (B = -229.44, t = -3.82,p < .001). Acute activation of classical intereukin-6 signaling might emerge as a heretofore unrecognized novel mechanism that could be harnessed to expand the antidepressant armamentarium.

Nutritional Criminology: Why the Emerging Research on Ultra-Processed Food Matters to Health and Justice.

There is mounting concern over the potential harms associated with ultra-processed foods, including poor mental health and antisocial behavior. Cutting-edge research provides an enhanced understanding of biophysiological mechanisms, including microbiome pathways, and invites a historical reexamination of earlier work that investigated the relationship between nutrition and criminal behavior. Here, in this perspective article, we explore how this emergent research casts new light and greater significance on previous key observations. Despite expanding interest in the field dubbed 'nutritional psychiatry', there has been relatively little attention paid to its relevancy within criminology and the criminal justice system. Since public health practitioners, allied mental health professionals, and policymakers play key roles throughout criminal justice systems, a holistic perspective on both historical and emergent research is critical. While there are many questions to be resolved, the available evidence suggests that nutrition might be an underappreciated factor in prevention and treatment along the criminal justice spectrum. The intersection of nutrition and biopsychosocial health requires transdisciplinary discussions of power structures, industry influence, and marketing issues associated with widespread food and social inequalities. Some of these discussions are already occurring under the banner of 'food crime'. Given the vast societal implications, it is our contention that the subject of nutrition in the multidisciplinary field of criminology-referred to here as nutritional criminology-deserves increased scrutiny. Through combining historical findings and cutting-edge research, we aim to increase awareness of this topic among the broad readership of the journal, with the hopes of generating new hypotheses and collaborations.

Elevated body temperature is associated with depressive symptoms: results from the TemPredict Study.

Correlations between altered body temperature and depression have been reported in small samples; greater confidence in these associations would provide a rationale for further examining potential mechanisms of depression related to body temperature regulation. We sought to test the hypotheses that greater depression symptom severity is associated with (1) higher body temperature, (2) smaller differences between body temperature when awake versus asleep, and (3) lower diurnal body temperature amplitude. Data collected included both self-reported body temperature (using standard thermometers), wearable sensor-assessed distal body temperature (using an off-the-shelf wearable sensor that collected minute-level physiological data), and self-reported depressive symptoms from > 20,000 participants over the course of ~ 7 months as part of the TemPredict Study. Higher self-reported and wearable sensor-assessed body temperatures when awake were associated with greater depression symptom severity. Lower diurnal body temperature amplitude, computed using wearable sensor-assessed distal body temperature data, tended to be associated with greater depression symptom severity, though this association did not achieve statistical significance. These findings, drawn from a large sample, replicate and expand upon prior data pointing to body temperature alterations as potentially relevant factors in depression etiology and may hold implications for development of novel approaches to the treatment of major depressive disorder.

Toxoplasma gondii IgG Serointensity Is Positively Associated With Frailty.

BACKGROUND: Persistent inflammation related to aging ("inflammaging") is exacerbated by chronic infections and contributes to frailty in older adults. We hypothesized associations between Toxoplasma gondii (T. gondii), a common parasite causing an oligosymptomatic unremitting infection, and frailty, and secondarily between T. gondii and previously reported markers of immune activation in frailty. METHODS: We analyzed available demographic, social, and clinical data in Spanish and Portuguese older adults [N = 601; age: mean (SD) 77.3 (8.0); 61% women]. Plasma T. gondii immunoglobulin G (IgG) serointensity was measured with an enzyme-linked immunosorbent assay. The Fried criteria were used to define frailty status. Validated translations of Mini-Mental State Examination, Geriatric Depression Scale, and the Charlson Comorbidity Index were used to evaluate confounders. Previously analyzed biomarkers that were significantly associated with frailty in both prior reports and the current study, and also related to T. gondii serointensity, were further accounted for in multivariable logistic models with frailty as outcome. RESULTS: In T. gondii-seropositives, there was a significant positive association between T. gondii IgG serointensity and frailty, accounting for age (p = .0002), and resisting adjustment for multiple successive confounders. Among biomarkers linked with frailty, kynurenine/tryptophan and soluble tumor necrosis factor receptor II were positively associated with T. gondii serointensity in seropositives (p < .05). Associations with other biomarkers were not significant. CONCLUSIONS: This first reported association between T. gondii and frailty is limited by a cross-sectional design and warrants replication. While certain biomarkers of inflammaging were associated with both T. gondii IgG serointensity and frailty, they did not fully mediate the T. gondii-frailty association.

First Annual PACT Act Research Symposium on Veterans Health: A Colorado PACT Act Collaboration (CoPAC) Initiative.

In response to the Sergeant First Class Heath Robinson Honoring our Promise to Address Comprehensive Toxics (PACT) Act being signed into law, several research groups in Colorado organized the First Annual PACT Act Research Symposium for Veteran Health. The 2-day symposium was interested in research relevant to military exposures with a primary focus on respiratory and mental health. Information on the PACT Act, data sources in the Department of Veteran Affairs and DOD, and research opportunities at the Veteran Affairs were presented. The morning session centered on respiratory health, highlighting research conducted over the last two decades regarding deployment-related respiratory diseases. Despite the high prevalence of mental health disorders among Veterans, information presented during the afternoon sessions on mental health highlighted the dearth of research to date regarding psychological health and military-related exposures. Policymakers, clinicians, and researchers were encouraged to adopt a life-course approach when conceptualizing physical and psychological exposures. On the second day of meetings, a smaller group of participants discussed next steps in military exposure research, as well as priorities for future research. Per the latter, recommendations for future research were made regarding the need for more precise exposure characterization, longitudinal data collection, and efforts to increase understanding regarding disease pathogenesis, as well as the impact of exposures across multiple organs. Such efforts will require interdisciplinary collaboration.

Association of homelessness and diet on the gut microbiome: a United States-Veteran Microbiome Project (US-VMP) study.

Military veterans account for 8% of homeless individuals living in the United States. To highlight associations between history of homelessness and the gut microbiome, we compared the gut microbiome of veterans who reported having a previous experience of homelessness to those from individuals who reported never having experienced a period of homelessness. Moreover, we examined the impact of the cumulative exposure of prior and current homelessness to understand possible associations between these experiences and the gut microbiome. Microbiome samples underwent genomic sequencing and were analyzed based on alpha diversity, beta diversity, and taxonomic differences. Additionally, demographic information, dietary data, and mental health history were collected. A lifetime history of homelessness was found to be associated with alcohol use disorder, substance use disorder, and healthy eating index compared to those without such a history. In terms of differences in gut microbiota, beta diversity was significantly different between veterans who had experienced homelessness and veterans who had never been homeless (P = 0.047, weighted UniFrac), while alpha diversity was similar. The microbial community differences were, in part, driven by a lower relative abundance of Akkermansia in veterans who had experienced homelessness (mean; range [in percentages], 1.07; 0-33.9) compared to veterans who had never been homeless (2.02; 0-36.8) (P = 0.014, ancom-bc2). Additional research is required to facilitate understanding regarding the complex associations between homelessness, the gut microbiome, and mental and physical health conditions, with a focus on increasing understanding regarding the longitudinal impact of housing instability throughout the lifespan.IMPORTANCEAlthough there are known stressors related to homelessness as well as chronic health conditions experienced by those without stable housing, there has been limited work evaluating the associations between microbial community composition and homelessness. We analyzed, for the first time, bacterial gut microbiome associations among those with experiences of homelessness on alpha diversity, beta diversity, and taxonomic differences. Additionally, we characterized the influences of diet, demographic characteristics, military service history, and mental health conditions on the microbiome of veterans with and without any lifetime history of homelessness. Future longitudinal research to evaluate the complex relationships between homelessness, the gut microbiome, and mental health outcomes is recommended. Ultimately, differences in the gut microbiome of individuals experiencing and not experiencing homelessness could assist in identification of treatment targets to improve health outcomes.

A cross-sectional study of correlations among blood-based biomarkers for intestinal permeability: A pilot study of United States veterans with posttraumatic stress disorder symptoms.

While many studies of intestinal permeability (IP) are focused on those with gastrointestinal (GI) disorders, there is a rising trend to analyze IP among individuals with mental health conditions including posttraumatic stress disorder (PTSD) with and without diagnosed GI conditions. This interest stems from the association between gut dysbiosis and chronic inflammation, which are mechanisms linked to stress-related somatic and mental health conditions. Efforts to date have resulted in the exploration of non-invasive and feasible measures to identify an IP biomarker that could also serve as a treatment target. Additionally, those conducting studies regarding IP often recruit individuals without health problems and compare levels of biomarkers of IP to those obtained from participants with conditions of interest. This study aimed to assess correlations between blood-based biomarkers of IP, as well as examine the association between blood-based biomarkers of IP and PTSD symptoms. Blood was sampled from seventeen United States military Veterans with variable severity of PTSD symptoms per the posttraumatic checklist for DSM-5 (PCL-5) (n = 6 with scores over 31 indicating clinically meaningful symptoms of PTSD; overall range 0-49, mean 20.8, standard deviation 15.7) and analyzed blood biomarkers of IP including citrulline, diamine oxidase, glucagon-like peptide-2, intestinal fatty-acid binding protein, lipopolysaccharide binding protein, lipopolysaccharide, and zonulin. Correlations between the IP blood-based biomarkers ranged from ρ of -0.31 to 0.35. None of the measured biomarkers were significantly correlated to PTSD symptom severity scores (ρ of -0.34 to 0.05). Although based on limited sample size, our results call into question the specificity of blood-based biomarkers of IP when: (1) studying persons with and without PTSD symptoms in whom clinical GI disorders are not necessarily the focus of the study; and (2) comparing IP results among individuals with well-defined disease states to those without the disease (e.g., controls). Further studies are needed to explore the role of external factors (e.g., nutrition, obesity, alcohol use) on IP and to determine if the biomarkers studied are appropriate for measuring IP in people with a range of symptoms related to PTSD.

Food desert residence has limited impact on veteran fecal microbiome composition: a U.S. Veteran Microbiome Project study.

IMPORTANCE: Social and economic inequities can have a profound impact on human health. The inequities could result in alterations to the gut microbiome, an important factor that may have profound abilities to alter health outcomes. Moreover, the strong correlations between social and economic inequities have been long understood. However, to date, limited research regarding the microbiome and mental health within the context of socioeconomic inequities exists. One particular inequity that may influence both mental health and the gut microbiome is living in a food desert. Persons living in food deserts may lack access to sufficient and/or nutritious food and often experience other inequities, such as increased exposure to air pollution and poor access to healthcare. Together, these factors may confer a unique risk for microbial perturbation. Indeed, external factors beyond a food desert might compound over time to have a lasting effect on an individual's gut microbiome. Therefore, adoption of a life-course approach is expected to increase the ecological validity of research related to social inequities, the gut microbiome, and physical and mental health.

The Role of Dorsal Raphe Nucleus Serotonergic Systems in Emotional Learning and Memory in Male BALB/c Mice.

Selective serotonin reuptake inhibitors (SSRIs) are the first-line pharmacological treatment for a variety of anxiety-, trauma- and stressor-related disorders. Although they are efficacious, therapeutic improvements require several weeks of treatment and are often associated with an initial exacerbation of symptoms. The dorsal raphe nucleus (DR) has been proposed as an important target for the modulation of emotional responses and the therapeutic effects of SSRIs. Using a fear-conditioning paradigm we aimed to understand how SSRIs affect emotional learning and memory, and their effects on serotonergic circuitry. Adult male BALB/c mice were treated with vehicle (n = 16) or the SSRI fluoxetine (18 mg/kg/d) acutely (n = 16), or chronically (21d, n = 16), prior to fear conditioning. Treatment was stopped, and half of the mice (n = 8/treatment group) were exposed to cued fear memory recall 72 h later. Activation of DR serotonergic neurons during fear conditioning (Experiment 1) or fear memory recall (Experiment 2), was measured using dual-label immunohistochemistry for Tph2 and c-Fos. Acute and chronic fluoxetine treatment reduced associative fear learning without affecting memory recall and had opposite effects on anxiety-like behaviour. Acute fluoxetine decreased serotonergic activity in the DR, while chronic treatment led to serotonergic activity that was indistinguishable from that of control levels in DRD and DRV subpopulations. Chronic fluoxetine facilitated fear extinction, which was associated with rostral DRD inhibition. These findings provide further evidence that SSRIs can alter aspects of learning and memory processes and are consistent with a role for discrete populations of DR serotonergic neurons in regulating fear- and anxiety-related behaviours.

Gut Microbiome and Lipidome Signatures in Irritable Bowel Syndrome Patients from a Low-Income, Food-Desert Area: A Pilot Study.

Irritable bowel syndrome (IBS) is a common gastroenterological disorder with triggers such as fructose. We showed that our IBS patients suffering from socioeconomic challenges have a significantly high consumption of high-fructose corn syrup (HFCS). Here, we characterize gut microbial dysbiosis and fatty acid changes, with respect to IBS, HFCS consumption, and socioeconomic factors. Fecal samples from IBS patients and healthy controls were subjected to microbiome and lipidome analyses. We assessed phylogenetic diversity and community composition of the microbiomes, and used linear discriminant analysis effect size (LEfSe), analysis of compositions of microbiomes (ANCOM) on highly co-occurring subcommunities (modules), least absolute shrinkage and selection operator (LASSO) on phylogenetic isometric log-ratio transformed (PhILR) taxon abundances to identify differentially abundant taxa. Based on a Procrustes randomization test, the microbiome and lipidome datasets correlated significantly (p = 0.002). Alpha diversity correlated with economic factors (p < 0.001). Multiple subsets of the phylogenetic tree were associated with HFCS consumption (p < 0.001). In IBS patients, relative abundances of potentially beneficial bacteria such as Monoglobaceae, Lachnospiraceae, and Ruminococcaceae were lower (p = 0.007), and Eisenbergiella, associated with inflammatory disorders, was higher. In IBS patients, certain saturated fatty acids were higher and unsaturated fatty acids were lower (p < 0.05). Our study aims first to underscore the influence of HFCS consumption and socioeconomic factors on IBS pathophysiology, and provides new insights that inform patient care.

Diazepam effects on anxiety-related defensive behavior of male and female high and low open-field activity inbred mouse strains.

Open-field activity is a commonly used measure of anxiety-related behavior in rodents. The inbred High and Low Activity strains of mice, selected for extreme differences in open-field activity, have been used as a genetic model of anxiety-related behaviors. These selected strains have been thoroughly studied through extensive behavioral testing, quantitative trait locus (QTL) mapping, whole-genome sequencing, and RNA sequencing, to uncover phenotypic and genotypic differences related to anxiety-related behavior. However, the effects of anxiolytic drugs on anxiety-related behavior in these strains have not been studied previously. This study allowed us to expand on previous findings to further characterize the anxiety-related behavior of these unique strains, using an anxiolytic drug. The goal of this study was to determine whether the treatment of adult male and female High Activity (low anxiety) and Low Activity (high anxiety) mice with diazepam, an agonist at the benzodiazepine allosteric site on the GABAA receptor and a drug commonly prescribed to treat anxiety disorders in humans, led to decreases in anxiety-like defensive behavioral responses as assessed in the open-field test (OFT) and elevated plus-maze (EPM). We tested the effects of three doses of diazepam (0, 0.5, 1.0, 3.0 mg/kg, i.p.), given 30 min before behavioral testing to one High Activity strain (H2) and two Low Activity strains (L1 and L2). There was an anxiolytic effect of diazepam observed in the High Activity strain, with more entries into the open arms of the elevated plus-maze, an effect similar to that seen in common mouse strains. However, the only anxiolytic effect of diazepam seen in the Low Activity strains was a reduction in stretch attend posture (SAP). Low Activity strains also displayed freezing behavior in both the OFT and EPM. The combination of the observed freezing behavior, that was not reduced by diazepam, and the reduction in SAP seen with diazepam, suggests a more complex phenotype that includes a component of innate fear in addition to anxiety-related risk assessment behaviors. Since fear and anxiety are distinguishable traits, and both contribute to human anxiety disorders, these results provide novel insight about interpretation of previous genetic and phenotypic differences observed between the High and Low Activity strains.

Subcutaneous Mycobacterium vaccae ameliorates the effects of early life adversity alone or in combination with chronic stress during adulthood in male and female mice.

Chronic psychosocial stress is a burden of modern society and poses a clear risk factor for a plethora of somatic and affective disorders, of which most are associated with an activated immune status and chronic low-grade inflammation. Preclinical and clinical studies further suggest that a failure in immunoregulation promotes an over-reaction of the inflammatory stress response and, thus, predisposes an individual to the development of stress-related disorders. Therefore, all genetic (i.e., sex) and environmental (i.e., early life adversity; ELA) factors facilitating an adult's inflammatory stress response are likely to increase their stress vulnerability. In the present study we investigated whether repeated subcutaneous (s.c.) administrations with a heat-killed preparation of Mycobacterium vaccae (M. vaccae; National Collection of Type Cultures (NCTC) 11659), an abundant soil saprophyte with immunoregulatory properties, are protective against negative behavioral, immunological and physiological consequences of ELA alone or of ELA followed by chronic psychosocial stress during adulthood (CAS) in male and female mice. ELA was induced by the maternal separation (MS) paradigm, CAS was induced by 19 days of chronic subordinate colony housing (CSC) in males and by a 7-week exposure to the social instability paradigm (SIP) in females. Our data indicate that ELA effects in both sexes, although relatively mild, were to a great extent prevented by subsequent s.c. M. vaccae administrations. Moreover, although the use of different paradigms for males and females impedes a direct comparison, male mice seemed to be more susceptible to CAS than females, with only females benefitting slightly from the stress protective effects of s.c. M. vaccae administrations when given prior to CAS alone. Finally, our data support the hypothesis that female mice are more vulnerable to the additive effects of ELA and CAS than male mice and that s.c. M. vaccae administrations subsequent to ELA but prior to CAS are protective in both sexes. Taken together and considering the limitation that CAS in males and females was induced by different paradigms, our findings are consistent with the hypotheses that murine stress vulnerability during different phases of life is strongly sex dependent and that developing immunoregulatory approaches, such as repeated s.c. administrations with immunoregulatory microorganisms, have potential for prevention/treatment of stress-related disorders.

The Many Hosts of Mycobacteria 9 (MHM9): A conference report.

The Many Hosts of Mycobacteria (MHM) meeting series brings together basic scientists, clinicians and veterinarians to promote robust discussion and dissemination of recent advances in our knowledge of numerous mycobacterial diseases, including human and bovine tuberculosis (TB), nontuberculous mycobacteria (NTM) infection, Hansen's disease (leprosy), Buruli ulcer and Johne's disease. The 9th MHM conference (MHM9) was held in July 2022 at The Ohio State University (OSU) and centered around the theme of "Confounders of Mycobacterial Disease." Confounders can and often do drive the transmission of mycobacterial diseases, as well as impact surveillance and treatment outcomes. Various confounders were presented and discussed at MHM9 including those that originate from the host (comorbidities and coinfections) as well as those arising from the environment (e.g., zoonotic exposures), economic inequality (e.g. healthcare disparities), stigma (a confounder of leprosy and TB for millennia), and historical neglect (a confounder in Native American Nations). This conference report summarizes select talks given at MHM9 highlighting recent research advances, as well as talks regarding the historic and ongoing impact of TB and other infectious diseases on Native American Nations, including those in Southwestern Alaska where the regional TB incidence rate is among the highest in the Western hemisphere.

Prior stress and vasopressin promote corticotropin-releasing factor inhibition of serotonin release in the central nucleus of the amygdala.

Corticotropin-releasing factor (CRF) is essential for coordinating endocrine and neural responses to stress, frequently facilitated by vasopressin (AVP). Previous work has linked CRF hypersecretion, binding site changes, and dysfunctional serotonergic transmission with anxiety and affective disorders, including clinical depression. Crucially, CRF can alter serotonergic activity. In the dorsal raphé nucleus and serotonin (5-HT) terminal regions, CRF effects can be stimulatory or inhibitory, depending on the dose, site, and receptor type activated. Prior stress alters CRF neurotransmission and CRF-mediated behaviors. Lateral, medial, and ventral subdivisions of the central nucleus of the amygdala (CeA) produce CRF and coordinate stress responsiveness. The purpose of these experiments was to determine the effect of intracerebroventricular (icv) administration of CRF and AVP on extracellular 5-HT as an index of 5-HT release in the CeA, using in vivo microdialysis in freely moving rats and high performance liquid chromatography (HPLC) analysis. We also examined the effect of prior stress (1 h restraint, 24 h prior) on CRF- and AVP-mediated release of 5-HT within the CeA. Our results show that icv CRF infusion in unstressed animals had no effect on 5-HT release in the CeA. Conversely, in rats with prior stress, CRF caused a profound dose-dependent decrease in 5-HT release within the CeA. This effect was long-lasting (240 min) and was mimicked by CRF plus AVP infusion without stress. Thus, prior stress and AVP functionally alter CRF-mediated neurotransmission and sensitize CRF-induced inhibition of 5-HT release, suggesting that this is a potential mechanism underlying stress-induced affective reactivity in humans.

Human microbiome transfer in the built environment differs based on occupants, objects, and buildings.

Compared to microbiomes on other skin sites, the bacterial microbiome of the human hand has been found to have greater variability across time. To increase understanding regarding the longitudinal transfer of the hand microbiome to objects in the built environment, and vice versa, 22 participants provided skin microbiome samples from their dominant hands, as well as from frequently and infrequently touched objects in their office environments. Additional longitudinal samples from home environments were obtained from a subset of 11 participants. We observed stability of the microbiomes of both the hand and built environments within the office and home settings; however, differences in the microbial communities were detected across the two built environments. Occupants' frequency of touching an object correlated to that object having a higher relative abundance of human microbes, yet the percent of shared microbes was variable by participants. Finally, objects that were horizontal surfaces in the built environment had higher microbial diversity as compared to objects and the occupants' hands. This study adds to the existing knowledge of microbiomes of the built environment, enables more detailed studies of indoor microbial transfer, and contributes to future models and building interventions to reduce negative outcomes and improve health and well-being.

Association of plasma cytokines and antidepressant response following mild-intensity whole-body hyperthermia in major depressive disorder.

Whole-body hyperthermia (WBH) shows promise for the treatment of major depressive disorder (MDD). Because MDD is associated with increased inflammation, and anti-inflammatory agents show some promise as antidepressants, the current study sought to identify the acute and longer-term immune effects of WBH in participants with MDD and to explore whether these effects associate with the procedure's antidepressant properties. Thirty participants who met DSM-IV-TR criteria for MDD were randomized to receive a single session of WBH (n = 16) or sham treatment (n = 14). Hamilton Depression Rating Scale (HDRS) scores were assessed at baseline and 1, 2, 4, and 6 weeks post-treatment (WBH vs. sham), and plasma cytokine concentrations were assessed at baseline, immediately post-treatment, and 1 and 4 weeks post-treatment. As previously reported, WBH produced a rapid and sustained antidepressant effect. When compared to sham, WBH increased plasma interleukin (IL)-6 immediately post-treatment (time by treatment: χ2(3, N=108) = 47.33, p < 0.001), while having no effect on other cytokines acutely and no impact on IL-6, or any other cytokine, at 1 or 4 weeks post treatment. In the study sample as a whole, increased IL-6 post-treatment was associated with reduced HDRS depression scores over the 6 weeks of follow-up (F(1, 102.3) = 6.74, p = 0.01). These results suggest a hitherto unrecognized relationship between hyperthermia, the immune system, and depression, and may point to WBH as a novel modality for exploring behavioral effects of IL-6 when the cytokine is activated in isolation from the inflammatory mediators with which it frequently travels.