Small intestinal bacterial overgrowth (SIBO) as a potential cause of impaired spermatogenesis

Depression, Inflammation, and Intestinal Permeability: Associations with Subjective and Objective Cognitive Functioning throughout Breast Cancer Survivorship

About one-in-three breast cancer survivors have lingering cognitive complaints and objective cognitive impairment. Chronic inflammation and intestinal permeability (i.e., leaky gut), two risk factors for cognitive decline, can also fuel depression-another vulnerability for cognitive decline. The current study tested whether depression accompanied by high levels of inflammation or intestinal permeability predicted lower subjective and objective cognitive function in breast cancer survivors. We combined data from four breast cancer survivor studies (n = 613); some had repeated measurements for a total of 1015 study visits. All participants had a blood draw to obtain baseline measures of lipopolysaccharide binding protein-a measure of intestinal permeability, as well as three inflammatory markers that were incorporated into an inflammatory index: C-reactive protein, interleukin-6, and tumor necrosis factor-α. They reported depressive symptoms on the Center for Epidemiological Studies depression scale (CES-D), and a binary variable indicated clinically significant depressive symptoms (CES-D ≥ 16). The Kohli (749 observations) and the Breast Cancer Prevention Trial (591 observations) scales assessed subjective cognitive function. Objective cognitive function tests included the trail-making test, Hopkins verbal learning test, Conners continuous performance test, n-back test, FAS test, and animal-naming test (239-246 observations). Adjusting for education, age, BMI, cancer treatment type, time since treatment, study visit, and fatigue, women who had clinically elevated depressive symptoms accompanied by heightened inflammation or intestinal permeability reported poorer focus and marginally poorer memory. However, poorer performance across objective cognitive measures was not specific to inflammation-associated depression. Rather, there was some evidence of lower verbal fluency; poorer attention, verbal learning and memory, and working memory; and difficulties with visuospatial search among depressed survivors, regardless of inflammation. By themselves, inflammation and intestinal permeability less consistently predicted subjective or objective cognitive function. Breast cancer survivors with clinically significant depressive symptoms accompanied by either elevated inflammation or intestinal permeability may perceive greater cognitive difficulty, even though depression-related objective cognitive deficits may not be specific to inflammation- or leaky-gut-associated depression.

The role of GnRH in Tibetan male sheep and goat reproduction

The hypothalamic-pituitary-gonadal (HPG) axis connects the hypothalamus, pituitary gland, and gonads. The regulation of reproductive processes includes integrating various factors from structural functions and environmental conditions in the HPG axis, with the outcome indication of these processes being the pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. These factors include feed consumption and nutritional condition, sex steroids, season/photoperiod, pheromones, age, and stress. GnRH pulsatile secretion affects the pattern of gonadotropin secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which then regulates both endocrine function and gamete maturation in the gonads. This regulates gonadotropins and testosterone (T) production. There is evidence that in males, GnRH participates in a variety of host behavioural and physiological processes such as the release of reproductive hormones, progression of spermatogenesis and sperm function, aggressive behaviour, and physiological metabolism. GnRH activates receptors expressed on Leydig cells and Sertoli cells, respectively to stimulate T secretion and spermatogenesis in the testis. Photoperiod affects the reproductive system of the hypothalamic-pituitary axis via rhythmic diurnal melatonin secretion. Increased release of melatonin promotes sexual activity, GnRH production, LH stimulation, and T production. This induces testicular functions, spermatogenesis, and puberty. GnRH reduces the release of LH by the pituitary through the cascade effect and decreases plasma concentration of T. Gut microbiota maintain sex steroid homeostasis and may induce reduction in reproduction productivity. Recently, findings of kisspeptin-neurokinin-dynorphin neuronal network in the brain have resulted in fast advances in how GnRH secretion is controlled. Emerging studies have also indicated that other neuropeptide analogues could be used in control reproduction procedures in various goat and sheep breeds. The Tibetan male sheep and goats reproduce on a seasonal basis and have high reproductive performance. This is a review for the role of GnRH in Tibetan male sheep and goats reproduction. This is intended to enhance reproductive knowledge for understanding the key roles of GnRH relating to male reproductive efficiency of Tibetan sheep or goats.

Seasonal Variation in Gut Microbiota of the Wild Daurian Ground Squirrel (Spermophilus dauricus): Metagenomic Insights into Seasonal Breeding

The Spermophilus dauricus, the wild Daurian ground squirrel, is known to exhibit seasonal breeding behavior. Although the importance of gut microbiota in animal digestion, metabolism, and immunity is well-established, the correlation between gut microbiota and seasonal breeding in this species remains inadequately explored. In the present study, using metagenomic sequencing technology, the compositions and functions of the gut microbiota of wild Daurian ground squirrels in different breeding seasons were explored. The dominant gut microbial phyla were Firmicutes and Bacteroidetes. The Firmicutes were predominant in the breeding season, whereas Bacteroidetes were predominant in the non-breeding season. At the genus level, Lactobacillus accumulated during the breeding season, whereas Odoribacter and Alistipes increased during the non-breeding season. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genome) annotations indicated that genes in gut samples were highly associated with metabolic functions. The differential expression gene analysis showed that genes related to the phosphotransferase system, cysteine, and methionine metabolism were highly expressed during the breeding season, whereas the non-breeding season upregulated genes were enriched in starch and sucrose metabolism and bacterial chemotaxis pathways. In conclusion, this study could provide a reference for investigating gut microbiota in seasonal breeding animals and offer new insight into gut microbial function.

ESHRE good practice recommendations on recurrent implantation failure

STUDY QUESTION

How should recurrent implantation failure (RIF) in patients undergoing ART be defined and managed?

SUMMARY ANSWER

This is the first ESHRE good practice recommendations paper providing a definition for RIF together with recommendations on how to investigate causes and contributing factors, and how to improve the chances of a pregnancy.

WHAT IS KNOWN ALREADY

RIF is a challenge in the ART clinic, with a multitude of investigations and interventions offered and applied in clinical practice, often without biological rationale or with unequivocal evidence of benefit.

STUDY DESIGN SIZE DURATION

This document was developed according to a predefined methodology for ESHRE good practice recommendations. Recommendations are supported by data from the literature, if available, and the results of a previously published survey on clinical practice in RIF and the expertise of the working group. A literature search was performed in PubMed and Cochrane focussing on 'recurrent reproductive failure', 'recurrent implantation failure', and 'repeated implantation failure'.

PARTICIPANTS/MATERIALS SETTING METHODS

The ESHRE Working Group on Recurrent Implantation Failure included eight members representing the ESHRE Special Interest Groups for Implantation and Early Pregnancy, Reproductive Endocrinology, and Embryology, with an independent chair and an expert in statistics. The recommendations for clinical practice were formulated based on the expert opinion of the working group, while taking into consideration the published data and results of the survey on uptake in clinical practice. The draft document was then open to ESHRE members for online peer review and was revised in light of the comments received.

MAIN RESULTS AND THE ROLE OF CHANCE

The working group recommends considering RIF as a secondary phenomenon of ART, as it can only be observed in patients undergoing IVF, and that the following description of RIF be adopted: 'RIF describes the scenario in which the transfer of embryos considered to be viable has failed to result in a positive pregnancy test sufficiently often in a specific patient to warrant consideration of further investigations and/or interventions'. It was agreed that the recommended threshold for the cumulative predicted chance of implantation to identify RIF for the purposes of initiating further investigation is 60%. When a couple have not had a successful implantation by a certain number of embryo transfers and the cumulative predicted chance of implantation associated with that number is greater than 60%, then they should be counselled on further investigation and/or treatment options. This term defines clinical RIF for which further actions should be considered. Nineteen recommendations were formulated on investigations when RIF is suspected, and 13 on interventions. Recommendations were colour-coded based on whether the investigations/interventions were recommended (green), to be considered (orange), or not recommended, i.e. not to be offered routinely (red).

LIMITATIONS REASONS FOR CAUTION

While awaiting the results of further studies and trials, the ESHRE Working Group on Recurrent Implantation Failure recommends identifying RIF based on the chance of successful implantation for the individual patient or couple and to restrict investigations and treatments to those supported by a clear rationale and data indicating their likely benefit.

WIDER IMPLICATIONS OF THE FINDINGS

This article provides not only good practice advice but also highlights the investigations and interventions that need further research. This research, when well-conducted, will be key to making progress in the clinical management of RIF.

STUDY FUNDING/COMPETING INTERESTS

The meetings and technical support for this project were funded by ESHRE. N.M. declared consulting fees from ArtPRED (The Netherlands) and Freya Biosciences (Denmark); Honoraria for lectures from Gedeon Richter, Merck, Abbott, and IBSA; being co-founder of Verso Biosense. He is Co-Chief Editor of Reproductive Biomedicine Online (RBMO). D.C. declared being an Associate Editor of Human Reproduction Update, and declared honoraria for lectures from Merck, Organon, IBSA, and Fairtility; support for attending meetings from Cooper Surgical, Fujifilm Irvine Scientific. G.G. declared that he or his institution received financial or non-financial support for research, lectures, workshops, advisory roles, or travelling from Ferring, Merck, Gedeon-Richter, PregLem, Abbott, Vifor, Organon, MSD, Coopersurgical, ObsEVA, and ReprodWissen. He is an Editor of the journals Archives of Obstetrics and Gynecology and Reproductive Biomedicine Online, and Editor in Chief of Journal Gynäkologische Endokrinologie. He is involved in guideline developments and quality control on national and international level. G.L. declared he or his institution received honoraria for lectures from Merck, Ferring, Vianex/Organon, and MSD. He is an Associate Editor of Human Reproduction Update, immediate past Coordinator of Special Interest Group for Reproductive Endocrinology of ESHRE and has been involved in Guideline Development Groups of ESHRE and national fertility authorities. D.J.M. declared being an Associate Editor for Human Reproduction Open and statistical Advisor for Reproductive Biomedicine Online. B.T. declared being shareholder of Reprognostics and she or her institution received financial or non-financial support for research, clinical trials, lectures, workshops, advisory roles or travelling from support for attending meetings from Ferring, MSD, Exeltis, Merck Serono, Bayer, Teva, Theramex and Novartis, Astropharm, Ferring. The other authors had nothing to disclose.

DISCLAIMER

This Good Practice Recommendations (GPR) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation. ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results. They do not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type. Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

Gut microbiota supports male reproduction via nutrition, immunity, and signaling

Gut microbiota (GM) is a major component of the gastrointestinal tract. Growing evidence suggests that it has various effects on many distal organs including the male reproductive system in mammals. GM and testis form the gut-testis axis involving the production of key molecules through microbial metabolism or de novo synthesis. These molecules have nutrition, immunity, and hormone-related functions and promote the male reproductive system via the circulatory system. GM helps maintain the integral structure of testes and regulates testicular immunity to protect the spermatogenic environment. Factors damaging GM negatively impact male reproductive function, however, the related mechanism is unknown. Also, the correlation between GM and testis remains to be yet investigated. This review discusses the complex influence of GM on the male reproductive system highlighting the impact on male fertility.

Bacterial overgrowth assessment and treatment among pediatric intestinal rehabilitation & nutrition support providers: an international survey of clinical practice patterns

BACKGROUND

Small bowel bacterial overgrowth (SBBO) is a common, but difficult to diagnose and treat problem in pediatric short bowel syndrome (SBS). Lack of clinical consensus criteria and unknown sensitivity and specificity of bedside diagnosis makes research on this potential SBS disease modifier challenging. The objective of this research was to describe clinical care of SBBO among international intestinal rehabilitation and nutrition support (IR&NS) providers treating patients with SBS.

METHODS & MATERIALS

A secure, confidential, international, electronic survey of IR&NS practitioners was conducted between March 2021 and May 2021. All analyses were conducted in the R statistical computing framework ™, version 4.0 RESULTS: 60% of respondents agreed and 0% strongly disagreed that abdominal pain, distension, emesis, diarrhea, and malodorous stool, were attributable to SBBO. No more than 20% of respondents strongly agreed and no more than 40% agreed that any sign or symptom was specific for SBBO. For a first-time diagnosis, 31 practitioners agreed with use of a 7-day course of a single antibiotic, with a majority citing Grade 5 evidence to inform their decisions (case series, uncontrolled studies, or expert opinion). The most common first antibiotic used to treat a new onset SBBO was metronidazole, and rifaximin was the 2^nd most commonly used. 100% of respondents reported they would consider a consensus algorithm for SBBO, even if the algorithm may be divergent from their current practice.

CONCLUSION

SBBO practice varies widely among experienced IR&NS providers. Development of a clinical consensus algorithm may help standardize care to improve research and care of this complex problem and to identify risks and benefits of chronic antibiotic use in SBS. This article is protected by copyright. All rights reserved.

Mucosa-Associated Microbial Profile Is Altered in Small Intestinal Bacterial Overgrowth

The overall gut microbial profile of patients with small intestinal bacterial overgrowth (SIBO) has not been thoroughly investigated. We investigated the microbial communities of mucosal specimens from the duodenum, ileum, sigmoid colon, and feces of patients with and without SIBO, as diagnosed by lactulose breath testing. The bacteria present in the mucosal and fecal samples were identified using 16S rRNA gene sequencing. Further analysis was performed using the linear discriminant analysis (LDA) effect size method, random forest analysis, and receiver operating characteristic analysis. The microbial diversities of the fecal samples were significantly lower than those of the mucosal samples from the duodenum, ileum, and sigmoid colon (P < 0.001, P < 0.001, and P < 0.001, respectively), while the bacterial compositions of the ileac mucosal samples and sigmoid mucosal samples were similar. The bacterial composition of either the fecal or duodenal mucosal samples were significantly different from those of the other three groups (ANOSIM R = 0.305, P = 0.001). The bacterial compositions of the mucosal samples of the duodenum, ileum, and sigmoid colon in the SIBO + subjects were significantly different from those of the SIBO− subjects (ANOSIM P = 0.039, 0.002, and 0.007, respectively). The relative abundances of 7, 18, and 8 genera were significantly different (LDA score > 3) in the mucosal samples of the duodenum, ileum, and sigmoid colon between the SIBO + and SIBO− groups. Four genera (Lactobacillus, Prevotella_1, Dialister, and norank_f__Ruminococcaceae) showed similar changes among the mucosal samples of the duodenum, ileum, and sigmoid colon in the SIBO + subjects. A signature consisting of four genera in the duodenal mucosa, three genera in the ileac mucosa, or six genera in the mucosa of the sigmoid colon exhibited predictive power for SIBO (area under the curve = 0.9, 0.93, and 0.87, respectively). This study provides a comprehensive profile of the gut microbiota in patients with SIBO. Dysbiosis was observed in the mucosa-associated gut microbiome but not in the fecal microbiome of patients with SIBO. Furthermore, we identified mucosa-associated taxa that may be potential biomarkers or therapeutic targets of SIBO. Further investigation is needed on their mechanisms and roles in SIBO.

Endotoxemia coupled with heightened inflammation predicts future depressive symptoms

OBJECTIVE

Cross-sectional data have linked gut barrier abnormalities and endotoxemia with depression, even among those without gastrointestinal symptoms. This study examined longitudinal associations between endotoxemia markers and depressive symptoms, as well as the role of inflammation in this relationship.

DESIGN

At three annual visits, 315 women (n=209 breast cancer survivors, n = 106 non-cancer patient controls, M=55 years old) completed the Center for Epidemiological Studies Depression questionnaire (CES-D) and provided blood samples to assess inflammatory markers - interleukin-6, tumor necrosis factor-alpha, and C-reactive protein - and endotoxemia markers - lipopolysaccharide-binding protein (LBP), soluble CD14 (sCD14), and their ratio.

RESULTS

Adjusting for key demographic variables, health behaviors, visit 1 depressive symptoms, and cancer status and treatment, women with higher visit 1 LBP and LBP/sCD14 had more depressive symptoms at the two subsequent annual visits. Illustrating the notable impact, a woman at the 75th percentile for LBP or LBP/sCD14 at visit 1 was 18 % more likely to report clinically significant depressive symptoms (CES-D ≥16) at follow-up than a woman in the lowest quartile. Cancer status and treatment type did not modulate this relationship. In contrast, visit 1 depressive symptoms did not predict endotoxemia at follow-up. A significant interaction between LBP/sCD14 and inflammatory burden suggested that visit 1 endotoxemia fueled depressive symptoms only in the context of elevated inflammation.

CONCLUSION

These results suggest that endotoxemia, combined with systemic inflammation, can drive depressive symptoms. These findings may implicate bacterial endotoxin translocation from the gut to the bloodstream in depression etiology. Interventions that reduce endotoxemia and inflammation may lessen the risk of depression.