The jejunum is the key factor in insulin resistance

Different lysine-to-methionine ratios in a low-protein diet affect the microbiome and metabolome, influencing the jejunal barrier function in Tibetan sheep

Introduction

The objective of this study was to evaluate the effects of the dietary lysine (Lys)/ methionine (Met) ratio in a low-protein diet on short-chain fatty acid (SCFA) profiles, villus morphology, antioxidant capacity, and immune status of the jejunum in Tibetan sheep.

Methods

A total of 90 weaned Tibetan sheep, each 2 months old with an initial weight of 15.37 ± 0.92 kg, were randomly divided into three treatment groups. These groups were supplemented with different Lys/Met ratios of 3 [low protein-high methionine (LP-H)], 2 [low protein-medium methionine (LP-M)], and 1 [low protein-low methionine (LP-L)] in the basal diet (10% crude protein). The feeding trial lasted 100 days, including a 10-day acclimation period and a 90-day experimental period.

Results

The hematoxylin-eosin (H&E) sections showed that the LP-L group had a significantly increased villus height compared to the LP-M and LP-H groups (p < 0.05). In addition, the LP-L group showed higher levels of Superoxide dismutase (SOD) activity and Total Antioxidant Capacity (T-AOC) concentrations (p < 0.05). A lower concentration of Interleukin-1 beta (IL-1β) was observed in the LP-H group (p < 0.05). The activities of α-amylase, chymotrypsin, and lipase were higher in the LP-L group compared to the LP-H group (p < 0.05). Bacterial sequencing showed that both Chao1 and ACE richness were significantly increased in the LP-L group (p < 0.05), suggesting that the species richness in the jejunum is connected to the ratio of dietary Lys/Met. Furthermore, lowering the dietary Lys/ Met ratio significantly increased the abundance of Romboutsia, the Ruminococcus gauvreauii group, the Lachnospiraceae NK3A20 group, Ruminococcus 2, and the Christensenellaceae R-7 group (p < 0.05) while decreasing the abundance of Methanobrevibacter (p < 0.05). Several differential metabolites, including beta-alanine, pantothenate, pantothenic acid, phosphoenolpyruvate, cysteine, adenosine 5'-diphosphate, isodeoxycholic acid, glutamate conjugated cholic acid, and 3-dehydrocholic acid, were significantly increased in the LP-L group (p < 0.05). The functional analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations indicated that these metabolites were mainly involved in pantothenate and CoA biosynthesis, ferroptosis, and the tricarboxylic acid cycle. Several genes related to barrier function, such as Occludin and Muc- 2, were upregulated in the LP-L group (p < 0.05), while IL-6 and TNF-α were downregulated (p < 0.05).

Discussion

Collectively, our results suggest that the dietary Met/ Lys ratio could affect the jejunal SCFA concentration by modulating the microbial community and regulating metabolism, thereby contributing to jejunal barrier function. Our findings provide a theoretical basis for the application of Lys/Met diet supplementation in the nutritional management of Tibetan sheep, particularly when reducing the dietary crude protein (CP) level.

Incretin hormones, obesity and gut microbiota

Over the past 40 years, the prevalence of obesity has risen dramatically, reaching epidemic proportions. By 2030 the number of people affected by obesity will reach 1.12 billion worldwide. Gastrointestinal hormones, namely incretins, play a vital role in the pathogenesis of obesity and its comorbidities. GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1), which are secreted from the intestine after nutrient intake and stimulate insulin secretion from pancreatic β cells, influence lipid metabolism, gastric empting, appetite and body weight. The gut microbiota plays an important role in various metabolic conditions, including obesity and type 2 diabetes and influences host metabolism through the interaction with enteroendocrine cells that modulate incretins secretion. Gut microbiota metabolites, such as short-chain fatty acids (SCFAs) and indole, directly stimulate the release of incretins from colonic enteroendocrine cells influencing host satiety and food intake. Moreover, bariatric surgery and incretin-based therapies are associated with increase gut bacterial richness and diversity. Understanding the role of incretins, gut microbiota, and their metabolites in regulating metabolic processes is crucial to develop effective strategies for the management of obesity and its associated comorbidities.

Comparative Study of Laparoscopic Sleeve Gastrectomy With or Without Jejunal Bypass

OBJECTIVE

We evaluated the weight loss effect of laparoscopic sleeve gastrectomy (LSG) and jejunal bypass (JJB) in treating obesity by analyzing and comparing the effects of LSG with or without JJB.

METHODS

A retrospective analysis was performed on the data of 150 patients with obesity who underwent bariatric metabolic surgery in Affiliated Xiaolan Hospital,Southern Medical University from October 2014 to April 2019. The patients were divided into two groups, LSG and LSG + JJB, according to the different surgical methods. The differences in the percentage of excess weight loss (%EWL) and total weight loss (TWL) between the two groups were statistically analyzed.

RESULTS

The %EWL of the patients in the LSG group reached the maximum value at one year and six months post-surgery and steadily decreased after two years post-surgery. In contrast, the %EWL of the patients in the LSG + JJB group gradually increased after two years post-surgery; however, no significant difference between the two groups was observed. The TWL in the LSG + JJB group was significantly greater than that in the LSG group at each follow-up point.

CONCLUSION

Postoperative %EWL was similar in both groups. The TWL in the LSG + JJB group was greater than that in the LSG group, and the postoperative recurrent weight gain rate in the LSG + JJB group was lower than that in the LSG group.

Intestinal heat shock proteins in metabolic syndrome: Novel mediators of obesity and its comorbidities resolution after metabolic surgery

Over the past 40 years, the prevalence of obesity has risen dramatically, reaching epidemic proportions. Metabolic surgery has proven to be highly effective in treating obesity, leading to significant improvements or complete resolution of obesity-related comorbidities. Research conducted in both animals and humans suggests that the metabolic benefits achieved through metabolic surgery cannot be solely attributed to weight loss. Indeed, there has been an increasing recognition of intestinal inflammation as a novel factor influencing obesity. The gastrointestinal tract is continuously exposed to dietary components, particularly diets rich in saturated fats, which are known to contribute to obesity. It is now widely accepted that heat shock proteins can be released from various cells including intestinal epithelial cells and act as proinflammatory signals. Several studies have shown that circulating levels of glucose-regulated protein 78 (GRP78) are increased in subjects with obesity and correlate with the severity of the disease. Moreover, mice with a partial knockout of GRP78 are protected from diet-induced obesity. In this review, we discuss the role of GRP78 in the development of obesity. Several evidence suggests that GRP78 can influence adipogenesis, lipid droplets stabilization, insulin resistance, and liver steatosis. We also provide an update on GRP78 regulation following metabolic surgery, focusing on the bypass of the small intestine as a key factor for GRP78 secretion. Finally, we discuss the potential role of monoclonal antibodies against GRP78 as a treatment for obesity.

Molecular remodeling of adipose tissue is associated with metabolic recovery after weight loss surgery

BACKGROUND

Bariatric surgery is an effective therapy for individuals with severe obesity to achieve sustainable weight loss and to reduce comorbidities. Examining the molecular signature of subcutaneous adipose tissue (SAT) following different types of bariatric surgery may help in gaining further insight into their distinct metabolic impact.

RESULTS

Subjects undergoing biliopancreatic diversion with duodenal switch (BPD-DS) showed a significantly higher percentage of total weight loss than those undergoing gastric bypass or sleeve gastrectomy (RYGB + SG) (41.7 ± 4.6 vs 28.2 ± 6.8%; p = 0.00005). Individuals losing more weight were also significantly more prone to achieve both type 2 diabetes and dyslipidemia remission (OR = 0.75; 95%CI = 0.51-0.91; p = 0.03). Whole transcriptome and methylome profiling showed that bariatric surgery induced a profound molecular remodeling of SAT at 12 months postoperative, mainly through gene down-regulation and hypermethylation. The extent of changes observed was greater following BPD-DS, with 61.1% and 49.8% of up- and down-regulated genes, as well as 85.7% and 70.4% of hyper- and hypomethylated genes being exclusive to this procedure, and mostly associated with a marked decrease of immune and inflammatory responses. Weight loss was strongly associated with genes being simultaneously differentially expressed and methylated in BPD-DS, with the strongest association being observed for GPD1L (r2 = 0.83; p = 1.4 × 10-6).

CONCLUSIONS

Present findings point to the greater SAT molecular remodeling following BPD-DS as potentially linked with higher metabolic remission rates. These results will contribute to a better understanding of the metabolic pathways involved in the response to bariatric surgery and will eventually lead to the development of gene targets for the treatment of obesity. Trial registration ClinicalTrials.gov NCT02390973.

Glucose Tolerance after Pancreatectomy: A Prospective Observational Follow-Up Study of Pancreaticoduodenectomy and Distal Pancreatectomy

BACKGROUND

Effects of pancreatectomy on glucose tolerance have not been clarified, and evidence regarding the difference in postoperative glucose tolerance between pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) is lacking.

STUDY DESIGN

This prospective, single-center observational study analyzed 40 patients undergoing PD and 29 patients undergoing DP (Clinical trial registry number UMIN000008122). Glucose tolerance, including insulin secretion (Δ C-peptide immunoreactivity, ΔCPR) and insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR) were assessed before and 1 month after pancreatectomy using the oral glucose tolerance test (OGTT) and glucagon stimulation test. We assessed long-term hemoglobin A1c (HbA1c) levels in patients, with a follow-up time of 3 years.

RESULTS

Percentages of patients diagnosed with abnormal OGTT decreased after PD (from 12 [30%] to 7 [17.5%] of 40 patients, p = 0.096); however, they increased after DP (from 4 [13.8%] to 8 [27.6%] of 29 patients, p = 0.103), although the changes were not statistically significant. ΔCPR decreased after both PD (from 3.2 to 1.0 ng/mL, p < 0.001) and DP (from 3.3 to 1.8 ng/mL, p < 0.001). HOMA-IR decreased after PD (from 1.10 to 0.68, p < 0.001), but did not change after DP (1.10 and 1.07, p = 0.42). Median HbA1c level was higher after DP than after PD for up to 3 years, but the differences were not statistically significant.

CONCLUSIONS

In comparisons of pre- and 1 month post-pancreatectomy data, glucose tolerance showed improvement after PD, whereas it worsened after DP. Insulin secretion decreased after both PD and DP. Insulin resistance improved after PD, but did not change after DP. Further studies are warranted to clarify mechanisms of improved insulin resistance after PD.