Effect of gut hormones on bone metabolism and their possible mechanisms in the treatment of osteoporosis. Frontiers in pharmacology Bone is a highly dynamic organ that changes with the daily circadian rhythm. During the day, bone resorption is suppressed due to eating, while it increases at night. This circadian rhythm of the skeleton is regulated by gut hormones. Until now, gut hormones that have been found to affect skeletal homeostasis include glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2), glucose-dependent insulinotropic polypeptide (GIP), and peptide YY (PYY), which exerts its effects by binding to its cognate receptors (GLP-1R, GLP-2R, GIPR, and Y1R). Several studies have shown that GLP-1, GLP-2, and GIP all inhibit bone resorption, while GIP also promotes bone formation. Notably, PYY has a strong bone resorption-promoting effect. In addition, gut microbiota (GM) plays an important role in maintaining bone homeostasis. This review outlines the roles of GLP-1, GLP-2, GIP, and PYY in bone metabolism and discusses the roles of gut hormones and the GM in regulating bone homeostasis and their potential mechanisms. 10.3389/fphar.2024.1372399

Biodiversity of Gut Microbiota: Impact of Various Host and Environmental Factors. BioMed research international Human bodies encompass very important symbiotic and mutualistic relationships with tiny creatures known as microbiota. Trillions of these tiny creatures including protozoa, viruses, bacteria, and fungi are present in and on our bodies. They play important roles in various physiological mechanisms of our bodies. In return, our bodies provide them with the habitat and food necessary for their survival. In this review, we comprehend the gut microbial species present in various regions of the gut. We can get benefits from microbiota only if they are present in appropriate concentrations, as if their concentration is altered, it will lead to dysbiosis of microbiota which further contributes to various health ailments. The composition, diversity, and functionality of gut microbiota do not remain static throughout life as they keep on changing over time. In this review, we also reviewed the various biotic and abiotic factors influencing the quantity and quality of these microbiota. These factors serve a significant role in shaping the gut microbiota population. 10.1155/2021/5575245

Seasonal Variation Influences on Intestinal Microbiota in Rats. Liu Jie,Song Yi,Lu Xiaoguang,Chen Tuo,Guo Wenxiu,Fan Zhiwei,Kang Xin,Wang Yu,Wang Yi Current microbiology Recently, several studies have indicated that the intestinal microbiota can be regulated by the individual attributes, and even the alternation of circadian rhythm. Inspired by this, we speculated that seasonal variation might also have some effect on the intestinal microbiota. A total of 11 Sprague-Dawley male rats, weighing 250-280 g, were divided into summer group (n = 5) and winter group (n = 6). Cages were individually ventilated at 20 ± 2 °C and 45-65% relative humidity with a circadian rhythm of 12/12 h. After 1 week of adaptively feeding, mucosal contents of jejunum, terminal ileum, and ascending colon were collected and analyzed by 16S rRNA Gene Amplicon Pyrosequencing. The results showed that intestinal microbiota of rats for the same strain were affected by season change under the same feeding condition and living environment. We should take seasonal factor into account in the future experimental design based on intestinal microbiome. 10.1007/s00284-018-1480-6

Short-term exposure to high relative humidity increases blood urea and influences colonic urea-nitrogen metabolism by altering the gut microbiota. Yin Hongmei,Zhong Yadong,Wang Hui,Hu Jielun,Xia Shengkun,Xiao Yuandong,Nie Shaoping,Xie Mingyong Journal of advanced research Introduction:Colonic urea-nitrogen metabolites have been implicated in the pathogenesis of certain diseases which can be affected by environmental factors. Objectives:We aimed to explore the influence of ambient humidity on colonic urea-nitrogen metabolism. Methods:Blood biochemical indexes, metabolites of intestinal tract, and gut microbiota composition of mice ( = 10/group) exposed to high relative humidity (RH, 90 ± 2%) were analyzed during the 14-day exposure. Results:After 12-h exposure, plasma blood urea nitrogen (BUN) level increased along with a decrease in the activity of erythrocyte Na/K -ATPase. Moreover, abnormal erythrocyte morphologies appeared after 3 days of exposure. The colonic BUN and ammonia levels increased significantly after the 12-h and 24-h exposure, respectively. The colonic level of amino acids, partly synthesized by gut microbiota using ammonia as the nitrogen source, was significantly higher on the 7th day. Furthermore, the level of fecal short-chain fatty acids was significantly higher after 3-day exposure and the level of branched-chain fatty acids increased on the 14th day. Overall, gut microbiota composition was continuously altered during exposure, facilitating the preferential proliferation of urea-nitrogen metabolism bacteria. Conclusion:Our findings suggest that short-term high RH exposure influences colonic urea-nitrogen metabolism by increasing the influx of colonic urea and altering gut microbiota, which might further impact the host health outcomes. 10.1016/j.jare.2021.03.004

Gut microbiota associated with appetite suppression in high-temperature and high-humidity environments. EBioMedicine BACKGROUND:Food is crucial for maintaining vital human and animal activities. Disorders in appetite control can lead to various metabolic disturbances. Alterations in the gut microbial composition can affect appetite and energy metabolism. While alterations in the gut microbiota have been observed in high-temperature and high-humidity (HTH) environments, the relationship between the gut microbiota during HTH and appetite remains unclear. METHODS:We utilised an artificial climate box to mimic HTH environments, and established a faecal bacteria transplantation (FMT) mouse model. Mendelian randomisation (MR) analysis was used to further confirm the causal relationship between gut microbiota and appetite or appetite-related hormones. FINDINGS:We found that, in the eighth week of exposure to HTH environments, mice showed a decrease in food intake and body weight, and there were significant changes in the intestinal microbiota compared to the control group. After FMT, we observed similar changes in food intake, body weight, and gut bacteria. Appetite-related hormones, including ghrelin, glucagon-like peptide-1, and insulin, were reduced in DH (mice exposed to HTH conditions) and DHF (FMT from mice exposed to HTH environments for 8 weeks), while the level of peptide YY initially increased and then decreased in DH and increased after FMT. Moreover, MR analysis further confirmed that these changes in the intestinal microbiota could affect appetite or appetite-related hormones. INTERPRETATION:Together, our data suggest that the gut microbiota is closely associated with appetite suppression in HTH. These findings provide novel insights into the effects of HTH on appetite. FUNDING:This work was supported by the National Natural Science Foundation of China and Guangzhou University of Chinese Medicine. 10.1016/j.ebiom.2023.104918