Project description:We investigated the effect of weight loss maintenance (WLM) and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity prone rats, WLM reduced fat oxidative capacity and down-regulated genes involved in fat metabolism. After weight was regained in rats, the genes involved in fat metabolism were still reduced. Mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, were subjected to our WLM and weight regain paradigm. We found that mCK-hLPL attenuated weight regain by potentiating energy expenditure.Irrespective of genotype, weight regain suppressed dietary fat oxidation and down-regulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain.
Project description:The present study was designed to identify determinants that foreshadow successful weight maintenance. More specifically, we examined whether subcutaneous adipose tissue (scAT) gene expression of participants who experience successful weight maintenance following caloric restriction differed from that of participants who regain weight. Forty women followed a dietary protocol consisting of an 8-week low calorie diet (LCD) and a 6-month weight maintenance phase. At the end of the protocol, participants were classified as weight maintainers (WM; 0-10% weight regain) and weight regainers (WR; 50-100% weight regain). Anthropometric measurements, plasma parameters, and scAT biopsies were taken before and after the LCD. Adipose tissue gene expression profiles were studied in all individuals before and after the LCD.
Project description:Most individuals do not maintain weight loss, and weight regain increases cardio-metabolic risk beyond that of obesity. Adipose inflammation directly contributes to insulin resistance; however, immune-related changes that occur with weight loss and weight regain are not well understood. Single cell RNA-sequencing was completed with CITE-sequencing and biological replicates to profile changes in murine immune subpopulations following obesity, weight loss, and weight cycling. Weight loss normalized glucose tolerance, however, type 2 immune cells did not repopulate adipose following weight loss. Many inflammatory populations persisted with weight loss and increased further following weight regain. Obesity drove T cell exhaustion and broad increases in antigen presentation, lipid handing, and inflammation that persisted with weight loss and weight cycling. This work provides critical groundwork for understanding the immunological causes of weight cycling-accelerated metabolic disease.
Project description:While weight loss is highly recommended for obesity, promoting inflammation resolution, >80% of those who lose weight will regain it back, resulting in worsening of disease outcomes (including cardiovascular disease), relative to never having lost weight. However, how weight loss and regain directly influence atherosclerotic inflammation was unknown and investigated in this stud. Using short-term caloric restriction (stCR) in obese mice, we found that weight loss promotes atherosclerosis resolution, independently of plasma cholesterol. Mechanistically, we found that this is partly attributed to a unique subset of macrophage, distinguished by high expression of the antibody receptor Fcgr4, that accumulated in epididymal adipose tissue and plaques with stCR and help to clear necrotic cores. Interestingly, our data suggest that eWAT-derived Fcgr4 macrophages contribute to the clearance of plaque necrotic cores. On the other hand, weight regain achieved by ab libitum feeding following the stCR phase resulted in acceleration of atherosclerosis progression and disappearance of Fcgr4 macrophages from both adipose and plaques. Furthermore, weight regain caused inflammatory reprogramming of bone marrow immune progenitors, retaining hyper-inflammatory capabilities for long periods thereafter.
Project description:Calorie restriction (CR) and fasting are common approaches to weight reduction, but the maintenance is difficult after resuming food consumption. Meanwhile, the gut microbiome associated with energy harvest alters dramatically in response to nutrient deprivation. Here, we reported that CR and high-fat diet (HFD) both remodeled the gut microbiota with similar microbial composition. Parabacteroides distasonis was most significantly decreased after CR or HFD. CR altered microbiota and reprogramed metabolism, resulting in a distinct serum bile acid profile characterized by depleting the proportion of non-12α-hydroxylated bile acids, ursodeoxycholic acid and lithocholic acid. Downregulation of UCP1 expression in brown adipose tissue and decreased serum GLP-1 were observed in the weight-rebound mice. Moreover, treatment with Parabacteroides distasonis or non-12α-hydroxylated bile acids ameliorated weight regain via increased thermogenesis. Our results highlighted the gut microbiota- bile acid crosstalk in rebound weight gain and Parabacteroides distasonis as a potential probiotic to prevent rapid post-CR weight gain.
Project description:Dieting is a popular yet often ineffective way to lower body weight, as the majority of people regain most of their pre-dieting weights in a relatively short time. The underlying molecular mechanisms driving weight regain and the increased risk for metabolic disease are still incompletely understood. Here we investigate the molecular alterations inherited from a history of obesity. In our model, male HFD fed obese C57BL/6J mice, were switched to a low caloric chow diet, resulting in a decline of body weight to that of lean mice. Within seven weeks after diet switch, most obesity associated phenotypes, such as body mass, glucose intolerance and blood metabolite levels were reversed. However, hepatic inflammation, hepatic steatosis as well as hypertrophy and inflammation of perigonadal, but not subcutaneous, adipocytes persisted in formerly obese mice. Transcriptional profiling of liver and perigonadal fat revealed an upregulation of pathways associated with immune function and cellularity. Thus, we show that weight reduction leaves signs of inflammation in liver and perigonadal fat, indicating that persisting proinflammatory signals in liver and adipose tissue could contribute to an increased risk of formerly obese subjects to develop the metabolic syndrome upon recurring weight gain.
Project description:Dieting is a popular yet often ineffective way to lower body weight, as the majority of people regain most of their pre-dieting weights in a relatively short time. The underlying molecular mechanisms driving weight regain and the increased risk for metabolic disease are still incompletely understood. Here we investigate the molecular alterations inherited from a history of obesity. In our model, male HFD fed obese C57BL/6J mice, were switched to a low caloric chow diet, resulting in a decline of body weight to that of lean mice. Within seven weeks after diet switch, most obesity associated phenotypes, such as body mass, glucose intolerance and blood metabolite levels were reversed. However, hepatic inflammation, hepatic steatosis as well as hypertrophy and inflammation of perigonadal, but not subcutaneous, adipocytes persisted in formerly obese mice. Transcriptional profiling of liver and perigonadal fat revealed an upregulation of pathways associated with immune function and cellularity. Thus, we show that weight reduction leaves signs of inflammation in liver and perigonadal fat, indicating that persisting proinflammatory signals in liver and adipose tissue could contribute to an increased risk of formerly obese subjects to develop the metabolic syndrome upon recurring weight gain.
Project description:The present study was designed to identify determinants that foreshadow successful weight maintenance. More specifically, we examined whether subcutaneous adipose tissue (scAT) gene expression of participants who experience successful weight maintenance following caloric restriction differed from that of participants who regain weight.
Project description:Opioids such as morphine have many beneficial properties as analgesics, however, opioids may induce multiple adverse gastrointestinal symptoms. We have recently demonstrated that morphine treatment results in significant disruption in gut barrier function leading to increased translocation of gut commensal bacteria. However, it is unclear how opioids modulate the gut homeostasis. By using a mouse model of morphine treatment, we studied effects of morphine treatment on gut microbiome. We characterized phylogenetic profiles of gut microbes, and found a significant shift in the gut microbiome and increase of pathogenic bacteria following morphine treatment when compared to placebo. In the present study, wild type mice (C57BL/6J) were implanted with placebo, morphine pellets subcutaneously. Fecal matter were taken for bacterial 16s rDNA sequencing analysis at day 3 post treatment. A scatter plot based on an unweighted UniFrac distance matrics obtained from the sequences at OTU level with 97% similarity showed a distinct clustering of the community composition between the morphine and placebo treated groups. By using the chao1 index to evaluate alpha diversity (that is diversity within a group) and using unweighted UniFrac distance to evaluate beta diversity (that is diversity between groups, comparing microbial community based on compositional structures), we found that morphine treatment results in a significant decrease in alpha diversity and shift in fecal microbiome at day 3 post treatment compared to placebo treatment. Taxonomical analysis showed that morphine treatment results in a significant increase of potential pathogenic bacteria. Our study shed light on effects of morphine on the gut microbiome, and its role in the gut homeostasis.
Project description:The goal of this observational study has the purpose of collecting biological samples from obese patients undergoing evaluation for weight loss by means of medical or endoscopic therapies; and of post bariatric surgery patients presenting with short- and long-term surgical complications. The aim is to enhance the overall understanding of the mechanisms leading to obesity, weight loss, failure to lose weight, and weight regain following treatment. Additional goals are to determine the efficacy of endoscopic and surgical procedures, to identify potential therapeutic targets and disease biomarkers that predict response to therapy.