Shorter sleep time relates to lower human defensin 5 secretion and compositional disturbance of the intestinal microbiota accompanied by decreased short-chain fatty acid production

Efficacy and mechanism of long-snake moxibustion for treating insomnia in breast cancer survivors: study protocol for a randomized controlled trial

Background

Insomnia (difficulty falling or staying asleep) is a common issue among breast cancer survivors, significantly impacting their quality of life. Current treatments, primarily pharmacological and psychological, have limitations: the former often causes side effects, while the latter faces accessibility barriers. Long-snake moxibustion (LSM), a traditional Chinese medicine (TCM) technique, involves applying moxibustion along the governor vessel, which is an important meridian in TCM that plays a key role in regulating brain function. LSM is characterized by its minimal side effects, ease of application, and cost-effectiveness, with preliminary studies supporting its potential for treating insomnia. This study aims to further investigate the therapeutic effectiveness of LSM in alleviating insomnia among breast cancer survivors and to explore its underlying mechanisms.

Methods

This single-center, rater-masked, randomized controlled trial will enroll 100 breast cancer survivors with chronic insomnia, who will be randomly assigned in a 1:1 ratio to either the LSM group or a waitlist control group. During the 4-week treatment period, all participants will receive standard care, with the LSM group additionally receiving LSM treatment twice a week. The primary efficacy outcome is the change in Insomnia Severity Index (ISI) score at the end of the intervention. Secondary outcomes include changes in hypnotic medication use, Pittsburgh Sleep Quality Index (PSQI) scores, Piper Fatigue Scale (PFS) scores, and Functional Assessment of Cancer Therapy-Breast (FACT-B) scores. Mechanistic evaluations will assess serum biochemical markers, gut microbiota composition, and metabolomic profiles.

Discussion

If proven effective, this trial will provide critical clinical evidence supporting LSM as a viable and accessible treatment for insomnia among breast cancer survivors. The findings could influence clinical practice by offering a non-pharmacological treatment option, improving patient outcomes, and reducing dependence on pharmacological interventions. Furthermore, exploring the underlying mechanisms may enhance our understanding of how LSM works, paving the way for future research.

Clinical trial registration

http://itmctr.ccebtcm.org.cn/, identifier ITMCTR2024000578.

Curcumin Ameliorated Glucocorticoid-Induced Osteoporosis While Modulating the Gut Microbiota and Serum Metabolome

Glucocorticoid-induced osteoporosis (GIOP) is the leading cause of secondary osteoporosis. Recently, the "bone-gut axis" theory has linked bone development with gut microbial diversity, community composition, and metabolites. Curcumin, a well-studied polyphenol, shows potential in mitigating bone loss and osteoporosis. Alendronate, a standard therapeutic agent for osteoporosis, serves as a positive control in this investigation. The study demonstrates the potency of curcumin in reducing bone loss and restoring bone mineral density, enhancing trabecular parameters notably through increased trabecular number, volume, and thickness and reduced bone marrow cavity size. Gut microbiome sequencing revealed that both curcumin and alendronate treatments similarly enhanced gut microbial diversity and altered microbiota composition, increasing beneficial bacteria (Akkermansia_muciniphila, Dubosiella_sp910585105, and Ruminococcus_sp910584195) while reducing harmful bacteria (Treponema_D_sp910584475 and Duncaniella_sp910584825). Furthermore, significant changes in serum levels of metabolites including raffinose, ursolic acid, spermidine, inosine, hypoxanthine, thiamine, and pantothenic acid were observed post-treatment with curcumin or alendronate. Importantly, these beneficial metabolites and microorganisms were negatively correlated with inflammatory cytokines. In conclusion, curcumin holds promise for use against GIOP by modulating the gut microbiome and serum metabolome as well as reducing systemic inflammation.

Bridging the gap between gut microbiota and sleep disorders through intermediary metabolites

BACKGROUND

Research has suggested an interaction between gut microbiota and sleep, yet the causal relationships between gut microbiota, metabolites, and sleep disorders remain unclear. This study aims to uncover these relationships.

METHODS

We obtained genome-wide data for 196 gut microbiota (GM) species (N = 18,340), 1,400 metabolites (N = 8,299), and sleep disorders (N = 361,194). Mendelian randomization(MR) analyses were conducted using the Inverse Variance Weighted (IVW) method, MR-Egger, Weighted Median method, Weighted Mode method, and Simple Mode method to infer causality. The IVW method was used for primary analysis results. Significant microbiota and causal metabolites were further analyzed to clarify the associations between the three. All results were tested for heterogeneity, pleiotropy, and sensitivity to assess the stability of the findings.

RESULTS

The Mendelian randomization results revealed causal relationships between four gut microbiota species and sleep disorders: Genus.Dorea, Genus.Parasutterell, Genus.Slackia, and Order.Bacillales. Additionally, we identified 39 causal metabolites Related to sleep disorders, with 7 of these being associated with 3 causal microbiota species at the genus level. All results showed no heterogeneity or horizontal pleiotropy.

CONCLUSION

Through two-sample Mendelian randomization studies, we identified three gut microbiota species at the genus level genetically linked to sleep disorders through seven plasma metabolites, revealing causal relationships between these three factors. These biomarkers provide new insights into the mechanisms of sleep disorders and may contribute to their prevention, diagnosis, and treatment.

Distinct vaginal microbiome and metabolome profiles in women with preterm delivery following cervical cerclage

Preterm birth (PTB) is a major cause of infant morbidity and mortality. The aim of this study was to investigate the effect of vaginal microbiota and metabolites on the outcome of pregnant women. In this study, a total of 127 pregnant women provided written informed consent prior to enrollment in accordance with the approved institutional guidelines, but only 45 pregnancies met the experimental requirements, and then blood and cervical vaginal fluid (CVF) samples were collected before delivery (at the second week after cervical cerclage). Pregnant women with PTB exhibited high white blood cell and neutrophil contents, high neutrophil-to-lymphocyte ratio (NLR), and high systemic inflammation response index (SIRI) in the blood. Vaginal microbiome revealed that the proportion of beneficial bacteria (including Lactobacillus, [Ruminococcus] gnavus group, and Megamonas) significantly decreased in the PTB group, and the proportion of harmful bacteria (including Desulfovibrionaceae, Helicobacter, and Gardnerella) significantly increased, which is strongly related to the biochemical parameters of blood (white blood cells, neutrophils, NLR, and SIRI). In addition, vaginal metabolomics-based liquid chromatography-Orbitrap-tandem mass spectrometry (LC-Orbitrap-MS/MS) found that the alteration in vaginal metabolites in pregnant women with PTB is involved in starch and sucrose metabolism; arginine and praline metabolism; galactose metabolism; purine metabolism; arginine metabolism; tryptophan metabolism and N-glycan biosynthesis; cysteine and methionine metabolism; taurine and hypotaurine metabolism; amino acid metabolism; propanoate metabolism; valine, leucine, and isoleucine biosynthesis; glycine, serine, and threonine metabolism; and steroid hormone biosynthesis. These results elaborated that distinct vaginal microbiome and metabolome profiles in women with preterm delivery following cervical cerclage provide valuable information for establishing the prediction models for PTB.

Better objective sleep quality is associated with higher gut microbiota richness in older adults

Aging is associated with disrupted sleep patterns, such as fragmented sleep and reduced efficiency, leading to negative health outcomes. There is evidence of a bidirectional relationship between sleep and gut microbiota, which plays a key role in the gut-brain axis and overall health. However, studies on this relationship in older adults have limited generalizability and show conflicting results, highlighting the need for further research. This study aimed to investigate the associations between sleep quality and gut microbiota composition in healthy Chinese older adults using subjective and objective sleep measures to capture various aspects of sleep quality and explore potential impacts on emotional well-being and cognitive performance. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire, while objective sleep quality was measured with actigraphy. Gut microbiota sequencing was performed on stool samples. The results show a robust positive association between gut microbiota richness and objective sleep quality in older adults, independent of subjective sleep quality and demographics, lifestyle, and health covariates. However, no significant link was found between gut microbiota richness and subjective sleep quality. Specific taxa like Bacteroidetes, Ruminococcus, Collinsella, Veillonella, and Holdemania were tentatively linked to sleep quality. These findings emphasize the connection between sleep quality and gut microbiota composition in older adults with potential research and clinical implications, improving our understanding of the mechanisms underlying the sleep-gut microbiota relationship and guiding the development of interventions for improving both sleep quality and gut health in older adults.

Self-Reported Symptoms of Obstructive Sleep Apnea are Associated with Increased Risk of Kidney Stones: A Cross-Sectional Study from NHANES 2015-2020

Objective

To investigate whether self-reported symptoms of obstructive sleep apnea (OSA), including snoring, snorting/stopping breathing, and sleepiness, are associated with increased risk of kidney stones.

Methods

This cross-sectional study was conducted based on the 2015-2020 National Health and Nutrition Examination Survey (NHANES). Self-reported symptoms of OSA and history of kidney stones were diagnosed via questionnaires. Multivariable logistic regression was used to determine the associations between self-reported symptoms of OSA and kidney stones. Subgroup analyses and interaction tests were performed to address this issue further.

Results

A total of 9,973 participants were enrolled, and the prevalence of kidney stones was 10.76%. Although no significant association was observed between frequent snoring and kidney stones after covariate adjustments (OR 1.033, 95% CI 0.726, 1.469 p = 0.850), frequent snorting/stopping breathing was associated with a greater risk of kidney stones after covariate adjustments (OR 1.655, 95% CI 1.262, 2.172, p = 0.002). Participants who often or almost always felt sleepy also had a greater risk of kidney stones after covariate adjustment (OR 1.651, 95% CI 1.222, 2.229; p = 0.004). The interaction tests suggested that marital status (p = 0.015) and smoking status (p < 0.001) significantly interacted with the association between snorting/stopping breathing and kidney stones.

Conclusion

Self-reported frequent snorting/stopping breathing and sleepiness may be associated with increased risk of kidney stones. Although these findings may emphasize prevention of kidney stones in these people, further research was still needed to verify our results.

Lipid metabolism: Novel approaches for managing idiopathic epilepsy

Epilepsy is a common neurological condition characterized by abnormal neuronal activity, often leading to cellular damage and death. There is evidence to suggest that lipid imbalances resulting in cellular death play a key role in the development of epilepsy, including changes in triglycerides, cholesterol, sphingolipids, phospholipids, lipid droplets, and bile acids (BAs). Disrupted lipid metabolism acts as a crucial pathological mechanism in epilepsy, potentially linked to processes such as cellular ferroptosis, lipophagy, and immune modulation of gut microbiota (thus influencing the gut-brain axis). Understanding these mechanisms could open up new avenues for epilepsy treatment. This study investigates the association between disturbances in lipid metabolism and the onset of epilepsy.

Association Between Dietary Fiber Intake and Sleep Disorders: Based on the NHANES Database

OBJECTIVE

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) database, the primary objective of this investigation was to examine the relationship between dietary fiber intake (DFI) and sleep disorders.

METHODS

For analysis, data from three consecutive cycles of NHANES (2009-2014) were pooled. The independent variable of interest was DFI, while the dependent variable was sleep disorders. Weighted logistic regression was employed to model the relationship between the two variables. Subgroup analyses were conducted, stratified, and adjusted to explore the association between DFI and sleep disorders.

RESULTS

This study encompassed a cohort of 14,360 samples. Logistic regression results revealed a significant inverse association between higher DFI and the risk of sleep disorders (OR: 0.99, 95% CI: 0.98-1.00, p = 0.005). Stratified analysis demonstrated significant interactive effects of gender and physical activity on the association between DFI and sleep disorders (interaction p = 0.017, p = 0.061). Quartile-stratified analysis of DFI showed that in the crude model, Q4 exhibited a significant protective impact against sleep disorders (OR: 0.76, 95% CI: 0.59-0.97, p = 0.026). In model I, which adjusted for demographic characteristics only, Q3 (OR: 0.74, 95% CI: 0.56-0.98, p = 0.036) and Q4 (OR: 0.70, 95% CI: 0.55-0.90, p = 0.006) had significant protective effects on sleep disorders. Additionally, gender subgroup analysis revealed that DFI had a significant impact on the female population, particularly in postmenopausal women, and was more pronounced in subjects with BMI > 30 kg/m2 (p = 0.011). Within the physical activity subgroup, there was a certain effect of DFI on improving sleep disorders in individuals with low activity intensity.

CONCLUSION

Increasing DFI had a protective effect in reducing the risk of sleep disorders. This protective effect may be more pronounced in the female population and individuals with low physical intensity.

Towards a personalized prediction, prevention and therapy of insomnia: gut microbiota profile can discriminate between paradoxical and objective insomnia in post-menopausal women

Background

Insomnia persists as a prevalent sleep disorder among middle-aged and older adults, significantly impacting quality of life and increasing susceptibility to age-related diseases. It is classified into objective insomnia (O-IN) and paradoxical insomnia (P-IN), where subjective and objective sleep assessments diverge. Current treatment regimens for both patient groups yield unsatisfactory outcomes. Consequently, investigating the neurophysiological distinctions between P-IN and O-IN is imperative for devising novel precision interventions aligned with primary prediction, targeted prevention, and personalized medicine (PPPM) principles.Working hypothesis and methodology.Given the emerging influence of gut microbiota (GM) on sleep physiology via the gut-brain axis, our study focused on characterizing the GM profiles of a well-characterized cohort of 96 Italian postmenopausal women, comprising 54 insomniac patients (18 O-IN and 36 P-IN) and 42 controls, through 16S rRNA amplicon sequencing. Associations were explored with general and clinical history, sleep patterns, stress, hematobiochemical parameters, and nutritional patterns.

Results

Distinctive GM profiles were unveiled between O-IN and P-IN patients. O-IN patients exhibited prominence in the Coriobacteriaceae family, including Collinsella and Adlercreutzia, along with Erysipelotrichaceae, Clostridium, and Pediococcus. Conversely, P-IN patients were mainly discriminated by Bacteroides, Staphylococcus, Carnobacterium, Pseudomonas, and respective families, along with Odoribacter.

Conclusions

These findings provide valuable insights into the microbiota-mediated mechanism of O-IN versus P-IN onset. GM profiling may thus serve as a tailored stratification criterion, enabling the identification of women at risk for specific insomnia subtypes and facilitating the development of integrated microbiota-based predictive diagnostics, targeted prevention, and personalized therapies, ultimately enhancing clinical effectiveness.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00369-1.

Association between yogurt and dietary supplements containing probiotic consumption with sleep disturbance in US adults: Results from NHANES, 2009-2018

Purpose

Sleep disorders are common globally. Probiotics may improve human microbial diversity, offering potential benefits for sleep disturbances by enhancing sleep quality and reducing disorders. We aimed to use a population-based study to investigate the association between yogurt (a probiotic food) and probiotic consumption with sleep disturbances in US adults.

Methods

A total of 49,693 adults from the 2009-2018 National Health and Nutrition Examination Survey (NHANES) were included in the analyses. Sleep disorders and sleep duration were assessed according to the Sleep Disorders Questionnaire. The Dietary Questionnaire evaluated yogurt and dietary supplements containing probiotic consumption. After adjusting for confounding factors, weighted multivariable logistic regression and subgroup analyses were used to assess the association between yogurt and probiotic consumption and sleep status.

Results

Of the study cohort, 3535 (14.24 %) participants consumed yogurt and/or dietary supplements containing probiotics. The prevalence of sleep disorders was 16.22 %. Only 53.51 % of the participants achieved the recommended amount of sleep (7-9 h), with 6.10 % and 33.48 % having excessive and insufficient sleep duration, respectively. Weighted Logistic regression models indicated a significant association of probiotic intake with a decreased risk of sleep disturbances compared with those without yogurt or probiotic consumption after adjustments. (For sleep disorders: OR: 0.96, 95 % CI 0.94-0.98, P < 0.001; for sleep duration: OR: 0.98, 95 % CI 0.96-1.00, P = 0.081) Moreover, the effect size of the probiotic intake on sleep was especially significant in sex, race, and BMI subgroups.

Conclusion

The present study first indicated that yogurt and probiotic consumption were associated with a reduced risk of sleep disturbances in US adults, particularly among males, whites, and those with a normal BMI. Incorporating yogurt or probiotics into the diet could serve as a public health strategy for improving sleep disturbances, though further investigation into the underlying mechanisms is needed.

Gut microbiota: a potential influencer of insomnia occurring after COVID-19 infection

The prevalence of insomnia has increased in recent years, significantly affecting the lives of many individuals. Coronavirus disease 2019 (COVID-19) infection has been found to have a substantial impact on the human gut microbiota (GM). Clinical studies have shown that the high prevalence, prolonged duration, and refractory treatment of insomnia symptoms following the COVID-19 pandemic may be related to the effect of COVID-19 infection on the GM. Therefore, the GM may be a potential target for the treatment of insomnia following COVID-19 infection. However, relevant studies have not been well-documented, and the GM has not been sufficiently analyzed in the context of insomnia treatment. Herein, we review the interaction between sleep and the GM, summarize the characteristics of COVID-19-induced abnormal changes in the GM and metabolites in patients with insomnia, and discuss potential mechanisms, including metabolic, immune, and neural pathways, by which these abnormal changes in the GM cause insomnia as well as the factors affecting the GM. Finally, we discuss the prospect of modulating the host GM community for the effective treatment of insomnia after COVID-19 infection and the need for further clinical studies.

Sleep promoting and omics exploration on probiotics fermented Gastrodia elata Blume

Fermenting Chinese medicinal herbs could enhance their bioactivities. We hypothesized probiotic-fermented gastrodia elata Blume (GE) with better potential to alleviate insomnia than that of unfermented, thus the changes in chemical composition and the insomnia-alleviating effects and mechanisms of fermented GE on pentylenetetrazole (PTZ)-induced insomnia zebrafish were explored via high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS), phenotypic, transcriptomic, and metabolomics analysis. The results demonstrated that probiotic fermented GE performed better than unfermented GE in increasing the content of chemical composition, reducing the displacement, average speed, and number of apoptotic cells in zebrafish with insomnia. Metabolomic investigation showed that the anti-insomnia effect was related to regulating the pathways of actin cytoskeleton and neuroactive ligand-receptor interactions. Transcriptomic and reverse transcription qPCR (RT-qPCR) analysis revealed that secondary fermentation liquid (SFL) significantly modulated the expression levels of neurod1, msh2, msh3, recql4, ercc5, rad5lc, and rev3l, which are mainly involved in neuron differentiation and DNA repair. Collectively, as a functional food, fermented GE possessed potential for insomnia alleviation.

Association of methyl donor nutrients dietary intake and sleep disorders in the elderly revealed by the intestinal microbiome

Currently, sleep disorders (SD) in the elderly are gaining prominence globally and are becoming a significant public health concern. Methyl donor nutrients (MDNs), such as vitamin B6, vitamin B12, folate, and choline, have been reported to have the potential to improve sleep disorders. Moreover, MDNs help to maintain gut flora homeostasis, and are closely associated with the development of SD. Nevertheless, there has been a lack of comprehensive human studies examining the association between MDNs intake and SD. In our study, we comprehensively evaluated the association between MDNs intake and SD in the elderly and used 16S rRNA gene sequencing to explore the underlying mechanism. We found that the SD group (n = 91) had a lower methyl-donor nutritional quality index (MNQI) and a trend toward lower intake compared to the control group (n = 147). Based on the intestinal microbiome, the beta diversity of the intestinal flora was higher in the high methyl-donor nutritional quality (HQ) group compared to the low methyl-donor nutritional quality (LQ) group, and it was lower in the SD group compared to the control group. This suggests that MDNs may regulate sleep by modulating the abundance distribution of the microbiota. Subsequently, we performed correlation analyses between the relative abundance of the microbiota, MDNs intake, and the Pittsburgh Sleep Quality Index (PSQI), identifying five genera with potential regulatory roles. The KEGG pathway analysis indicated that energy metabolism and one-carbon metabolism might be the pathways through which MDNs modulate sleep. This study offers dietary guidance strategies for managing SD in the elderly and provides insights for targeted microbiota intervention.

Gut microbiota profile in CDKL5 deficiency disorder patients

CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by global developmental delay, early-onset seizures, intellectual disability, visual and motor impairments. Unlike Rett Syndrome (RTT), CDD lacks a clear regression period. Patients with CDD frequently encounter gastrointestinal (GI) disturbances and exhibit signs of subclinical immune dysregulation. However, the underlying causes of these conditions remain elusive. Emerging studies indicate a potential connection between neurological disorders and gut microbiota, an area completely unexplored in CDD. We conducted a pioneering study, analyzing fecal microbiota composition in individuals with CDD (n = 17) and their healthy relatives (n = 17). Notably, differences in intestinal bacterial diversity and composition were identified in CDD patients. In particular, at genus level, CDD microbial communities were characterized by an increase in the relative abundance of Clostridium_AQ, Eggerthella, Streptococcus, and Erysipelatoclostridium, and by a decrease in Eubacterium, Dorea, Odoribacter, Intestinomonas, and Gemmiger, pointing toward a dysbiotic profile. We further investigated microbiota changes based on the severity of GI issues, seizure frequency, sleep disorders, food intake type, impairment in neuro-behavioral features and ambulation capacity. Enrichment in Lachnoclostridium and Enterobacteriaceae was observed in the microbiota of patients with more severe GI symptoms, while Clostridiaceae, Peptostreptococcaceae, Coriobacteriaceae, Erysipelotrichaceae, Christensenellaceae, and Ruminococcaceae were enriched in patients experiencing daily epileptic seizures. Our findings suggest a potential connection between CDD, microbiota and symptom severity. This study marks the first exploration of the gut-microbiota-brain axis in subjects with CDD. It adds to the growing body of research emphasizing the role of the gut microbiota in neurodevelopmental disorders and opens doors to potential interventions that target intestinal microbes with the aim of improving the lives of patients with CDD.

Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases

The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

The impact of plant-rich diets on sleep: a mini-review

Plant-rich diets (PRDs), also referred to as plant based diets, have been shown to have beneficial effects on various chronic diseases and all-cause mortality. However, limited data are available on the effect of such diets on sleep and sleep disorders. In this review article, we explore existing evidence and potential mechanisms by which PRDs may impact sleep and sleepiness. High-fat diets are associated with drowsiness, while fiber-rich diets improve sleep quality. Anti-inflammatory diets may benefit patients with sleep disturbances, and diets rich in tryptophan and serotonin precursors may improve sleep quality. Isoflavones and polyphenols present in PRDs may also have a positive impact on sleep. Furthermore, diets rich in plants may reduce the risk of obstructive sleep apnea and associated daytime sleepiness. Overall, the current knowledge about PRDs in sleep and sleep disorders is limited, and further research is needed to explore the potential advantages of this dietary approach in sleep disorders.

Alterations of Gut Microbiome Composition and Function Pre- and Post-Adenotonsillectomy in Children with Obstructive Sleep Apnea

IMPORTANCE

Obstructive sleep apnea (OSA) in children is linked with alterations in the gut microbiome. The influence of adenotonsillectomy (AT), a primary intervention for OSA, on gut microbiota dynamics relative to disease severity remains to be elucidated.

OBJECTIVE

This study aimed to investigate the impact of OSA severity and AT on the gut microbiome in pediatric patients.

DESIGN

A prospective observational study.

SETTING

Tertiary referral center.

PARTICIPANTS

A cohort of 55 pediatric patients treated with AT for OSA.

INTERVENTION

Total tonsillectomy and adenoidectomy procedures.

MAIN OUTCOME MEASURES

Comprehensive evaluations included in-laboratory polysomnography and 16S rRNA gut microbiome profiling at baseline, and again at 3rd and 12thmonth following surgery.

RESULTS

Initial findings showed uniform α-diversity across different severities of OSA, while β-diversity was significantly elevated in the severe OSA subgroup. Certain gut microbiota taxa (Lachnospiraceae NK4A136 group, Ruminococcaceae UCG-002, Ruminococcaceae UCG-014, Alloprevotella, Christensenellaceae R-7 group, Ruminococcaceae UCG-005, Lactobacillus murinus, and Prevotella nigrescens) were found to inversely correlate with the apnea-hypopnea index (AHI). Significant post-AT improvements in AHI and other polysomnographic metrics were observed. Notably, AHI changes post-AT were positively associated with microbial α-diversity (species richness), β-diversity, and specific bacterial taxa (Enterobacter, Parasutterella, Akkermansia, Roseburia, and Bacteroides plebeius DSM 17135), but negatively with other taxa (Fusicatenibacter, Bifidobacterium, UBA1819, Ruminococcus gnavus group, Bifidobacterium longum subsp. Longum, and Parabacteroides distasonis) and specific metabolic pathways (purine metabolism, transcription factors, and type II diabetes mellitus). The postoperative patterns of α- and β-diversity mirrored baseline values.

CONCLUSIONS AND RELEVANCE

This study documents significant changes in the gut microbiome of pediatric patients after AT, including variations in α- and β-diversities, bacterial communities, and inferred metabolic functions. These changes suggest a potential association between the surgical intervention and microbiome alterations, although further studies are necessary to discern the specific contributions of AT amidst possible confounding factors such as antibiotic use.

New Awareness of the Interplay Between the Gut Microbiota and Circadian Rhythms

Circadian rhythms influence various aspects of the biology and physiology of the host, such as food intake and sleep/wake cycles. In recent years, an increasing amount of genetic and epidemiological data has shown that the light/dark cycle is the main cue that regulates circadian rhythms. Other factors, including sleep/wake cycles and food intake, have necessary effects on the composition and rhythms of the gut microbiota. Interestingly, the gut microbiota can affect the circadian rhythm of hosts in turn through contact-dependent and contact-independent mechanisms. Furthermore, the gut microbiota has been shown to regulate the sleep/wake cycles through gut-brain-microbiota interaction. In addition to diabetes, the gut microbiota can also intervene in the progression of neuro- degenerative diseases through the gut-brain-microbiota interaction, and also in other diseases such as hypertension and rheumatoid arthritis, where it is thought to have a spare therapeutic potential. Even though fecal microbiota transplantation has good potential for treating many diseases, the risk of spreading intestinal pathogens should not be ignored.

Circadian rhythms in colonic function

A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.