Expression of Cholecystokinin and its Receptors in the Intestinal Tract of Type 2 Diabetes Patients and Healthy Controls

Type 2 diabetes mellitus related sarcopenia: a type of muscle loss distinct from sarcopenia and disuse muscle atrophy

Muscle loss is a significant health concern, particularly with the increasing trend of population aging, and sarcopenia has emerged as a common pathological process of muscle loss in the elderly. Currently, there has been significant progress in the research on sarcopenia, including in-depth analysis of the mechanisms underlying sarcopenia caused by aging and the development of corresponding diagnostic criteria, forming a relatively complete system. However, as research on sarcopenia progresses, the concept of secondary sarcopenia has also been proposed. Due to the incomplete understanding of muscle loss caused by chronic diseases, there are various limitations in epidemiological, basic, and clinical research. As a result, a comprehensive concept and diagnostic system have not yet been established, which greatly hinders the prevention and treatment of the disease. This review focuses on Type 2 Diabetes Mellitus (T2DM)-related sarcopenia, comparing its similarities and differences with sarcopenia and disuse muscle atrophy. The review show significant differences between the three muscle-related issues in terms of pathological changes, epidemiology and clinical manifestations, etiology, and preventive and therapeutic strategies. Unlike sarcopenia, T2DM-related sarcopenia is characterized by a reduction in type I fibers, and it differs from disuse muscle atrophy as well. The mechanism involving insulin resistance, inflammatory status, and oxidative stress remains unclear. Therefore, future research should further explore the etiology, disease progression, and prognosis of T2DM-related sarcopenia, and develop targeted diagnostic criteria and effective preventive and therapeutic strategies to better address the muscle-related issues faced by T2DM patients and improve their quality of life and overall health.

Research on the mechanism of regulating spleen-deficient obesity in rats by bawei guben huashi jiangzhi decoction based on multi-omics analysis

ETHNOPHARMACOLOGY RELEVANCE

Bawei Guben Huashi Jiangzhi Decoction (BGHJ), a traditional Chinese compound formula, comprises eight Chinese medicinal herbs: Codonopsis Radix, Atractylodis Macrocephalae Rhizoma, Cassiae Semen, Lysimachiae Herba, Edgeworthiae Gardner Flos, Oryzae Semen cum Monasco, Nelumbinis Folium, and Alismatis Rhizoma. It has the therapeutic effects of improving digestive and absorptive functions of the gastrointestinal tract, reducing cholesterol levels, and helping to lose weight. Therefore, BGHJ is mainly used to treat spleen-deficient obesity (SDO) clinically.

AIM OF THE STUDY

This study aims to examine the efficacy and mechanism of BGHJ in a model of SDO in rats, as well as the potentially involved constituents entering the blood and differential metabolites.

METHODS

The SDO rat model was replicated utilizing a high-fat and high-sugar diet in conjunction with exhaustive swimming. Subsequently, the rats were subjected to a six-week intervention comprising varying dosages of BGHJ and a positive control, orlistat. To evaluate the efficacy of BGHJ on SDO model rats, we first measured the rats' body weight, body surface temperature, spleen index, as well as biochemical indicators in the serum and colon, and then assessed the pathological state of the colon and liver. Afterward, we analyzed the 16S rDNA gut microbiota, non-targeted serum metabolomics, and serum pharmacology to study the main active components of BGHJ and its action mechanism against SDO model rats. In addition, we constructed a network diagram for overall visualization and analysis, and experimentally verified the predicted results. Finally, we used quantitative polymerase chain reaction (qPCR) to detect the gene expression of proopiomelanocortin (POMC) and neuropeptide Y (NPY) indicators in rat hypothalamic neurons. We quantitatively targeted the detection of neurotransmitters dopamine (DA), acetylcholine (Ach), 5-hydroxytryptamine (5-HT), and noradrenaline (NA) in rat hypothalamus.

RESULTS

The results demonstrated that all dosage regimens of BGHJ exhibited the capacity to moderately modulate parameters including body weight, surface temperature, spleen index, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), 5-HT, interleukin 6 (IL-6) and interleukin 17 (IL-17), while concurrently reducing hepatic lipid droplet deposition and restoring intestinal integrity. Subsequent experimental results showed that we successfully identified 27 blood components of BGHJ and identified 52 differential metabolites in SDO model rats. At the same time, the experiment proved that BGHJ could effectively inhibit the metabolic pathway of arachidonic acid. In addition, BGHJ can also restore the intestinal microbiota composition of SDO model rats. Finally, we also found that BGHJ could regulate the expression of hypothalamic neurons and neurotransmitters.

CONCLUSIONS

The research revealed the main active ingredients of BGHJ and its mechanism against SDO model rats through gut microbiota, non-target serum metabolomics, and serum drug chemistry.

The cckOMA syndrome and its relation to the Zollinger-Ellison syndrome: a diagnostic challenge

OBJECTIVE

Among patients with enteropancreatic neuroendocrine tumor syndromes only one case with a cholecystokinin (CCK) secreting tumor has been reported. She had significant hyperCCKemia leading to a specific syndrome of severe diarrheas, weight loss, repeated duodenal ulcers and a permanently contracted gallbladder with gallstones. There are, however, reasons to believe that further CCKomas exist, for instance among Zollinger-Ellison patients with normal plasma gastrin concentrations. The present review is a call to gastroenterologists for awareness of such CCKoma patients.

METHOD

After a short case report, the normal endocrine and oncological biology of CCK is described. Subsequently, the CCKoma symptoms are discussed with particular reference to the partly overlapping symptoms of the Zollinger-Ellison syndrome. In this context, the diagnostic use of truly specific CCK and gastrin assays are emphasized. The discussion also entails the problem of access to accurate CCK measurements.

CONCLUSION

Obviously, the clinical awareness about the CCKoma syndrome is limited. Moreover, it is also likely that the knowledge about the necessary specificity demands of diagnostic gastrin and CCK assays have obscured proper diagnosis of the CCKoma syndromes in man.

The bile-gut axis and metabolic consequences of cholecystectomy

Cholelithiasis and cholecystitis affect individuals of all ages and are often treated by surgical removal of the gallbladder (cholecystectomy), which is considered a safe, low-risk procedure. Nevertheless, recent findings show that bile and its regulated storage and excretion may have important metabolic effects and that cholecystectomy is associated with several metabolic diseases postoperatively. Bile acids have long been known as emulsifiers essential to the assimilation of lipids and absorption of lipid-soluble vitamins, but more recently, they have also been reported to act as metabolic signaling agents. The nuclear receptor, farnesoid X receptor (FXR), and the G protein-coupled membrane receptor, Takeda G protein-coupled receptor 5 (TGR5), are specific to bile acids. Through activation of these receptors, bile acids control numerous metabolic functions. Cholecystectomy affects the storage and excretion of bile acids, which in turn may influence the activation of FXR and TGR5 and their effects on metabolism including processes leading to metabolic conditions such as metabolic dysfunction-associated steatotic liver disease and metabolic syndrome. Here, with the aim of elucidating mechanisms behind cholecystectomy-associated dysmetabolism, we review studies potentially linking cholecystectomy and bile acid-mediated metabolic effects and discuss possible pathophysiological mechanisms behind cholecystectomy-associated dysmetabolism.

Expression of Secretin and its Receptor Along the Intestinal Tract in Type 2 Diabetes Patients and Healthy Controls

CONTEXT

The hormone secretin (SCT) is released from intestinal S cells and acts via the SCT receptor (SCTR). Circulating SCT levels increase after Roux-en-Y gastric bypass surgery and have been associated with massive weight loss and high remission rates of type 2 diabetes (T2D) linked to these operations. Exogenous SCT was recently shown to reduce ad libitum food intake in healthy volunteers.

OBJECTIVE

To understand SCT biology and its potential role in T2D pathophysiology, we examined the intestinal mucosal expression profile of SCT and SCTR and evaluated the density of S cells along the intestinal tract of individuals with T2D and healthy controls.

METHODS

Using immunohistochemistry and messenger RNA (mRNA) sequencing, we analyzed intestinal mucosa biopsies sampled along the small intestine at 30-cm intervals and from 7 well-defined anatomical sites along the large intestine (during 2 sessions of double-balloon enteroscopy) in 12 individuals with T2D and 12 healthy controls.

RESULTS

Both groups exhibited a progressive and similar decrease in SCT and SCTR mRNA expression and S-cell density along the small intestine, with reductions of 14, 100, and 50 times, respectively, in the ileum compared to the duodenum (used as reference). Negligible amounts of SCTR and SCT mRNA, as well as low S-cell density, were found in the large intestine. No significant differences were observed between the groups.

CONCLUSION

SCT and SCTR mRNA expression and S-cell density were abundant in the duodenum and decreased along the small intestine. Very low SCT and SCTR mRNA levels and S-cell numbers were observed in the large intestine, without aberrations in individuals with T2D compared to healthy controls.

History of key regulatory peptide systems and perspectives for future research

Throughout the 20th Century, regulatory peptide discovery advanced from the identification of gut hormones to the extraction and characterization of hypothalamic hypophysiotropic factors, and to the isolation and cloning of multiple brain neuropeptides. These discoveries were followed by the discovery of G-protein-coupled and other membrane receptors for these peptides. Subsequently, the systems physiology associated with some of these multiple regulatory peptides and receptors has been comprehensively elucidated and has led to improved therapeutics and diagnostics and their approval by the US Food and Drug Administration. In light of this wealth of information and further potential, it is truly a time of renaissance for regulatory peptides. In this perspective, we review what we have learned from the pioneers in exemplified fields of gut peptides, such as cholecystokinin, enterochromaffin-like-cell peptides, and glucagon, from the trailblazing studies on the key stress hormone, corticotropin-releasing factor, as well as from more recently characterized relaxin-family peptides and receptors. The historical viewpoints are based on our understanding of these topics in light of the earliest phases of research and on subsequent studies and the evolution of knowledge, aiming to sharpen our vision of the current state-of-the-art and those studies that should be prioritized in the future.

Expression of Neurotensin and Its Receptors Along the Intestinal Tract in Type 2 Diabetes Patients and Healthy Controls

CONTEXT

Enteroendocrine N cells secrete neurotensin (NTS). NTS reduces food intake in rodents and may increase insulin release. In humans, postprandial NTS responses increase following Roux-en-Y gastric bypass, associating the hormone with the glucose- and body weight-lowering effects of these procedures.

OBJECTIVE

We looked at N cell density and mucosal messenger RNA (mRNA) expression profiles of NTS and NTS receptors in type 2 diabetes (T2D) patients and healthy controls.

METHODS

Using double-balloon enteroscopy, 12 patients with T2D and 12 sex-, age-, and body mass index-matched healthy controls had mucosa biopsies taken from the entire length of the small intestine (at 30-cm intervals) and from 7 anatomically well-defined locations in the large intestine. Biopsies were analyzed using immunohistochemistry and mRNA sequencing.

RESULTS

N cell density and NTS mRNA expression gradually increased from the duodenum to the ileum, while negligible NTS-positive cells and NTS mRNA expression were observed in the large intestine. NTS receptor 1 and 2 mRNA expression were not detected, but sortilin, a single-pass transmembrane neuropeptide receptor of which NTS also is a ligand, was uniformly expressed in the intestines. Patients with T2D exhibited lower levels of NTS-positive cells and mRNA expression than healthy controls, but this was not statistically significant after adjusting for multiple testing.

CONCLUSION

This unique intestinal mapping of N cell density and NTS expression shows increasing levels from the small intestine's proximal to distal end (without differences between patients with T2D and healthy controls), while negligible N-cells and NTS mRNA expression were observed in the large intestine. Sortilin was expressed throughout the intestines in both groups; no NTS receptor 1 or 2 mRNA expression were detected.

Duodenal Mucosa: A New Target for the Treatment of Type 2 Diabetes

OBJECTIVE

After a high-fat and high-sugar diet, the duodenal mucosa of rodents proliferate and trigger the signal of insulin resistance, which may be the cause of type 2 diabetes (T2D). In response to this phenomenon, researchers have designed the duodenal mucosal resurfacing (DMR) procedure, mainly through the hydrothermal ablation procedure, to restore the normal mucosal surface, thereby correcting this abnormal metabolic signal. This article aims to understand the changes in duodenum before and after the onset or treatment of T2D, and the potential mechanisms of DMR procedure.

METHODS

A literature search of PubMed and Web of Science was conducted using appropriate keywords.

RESULTS

Both animal and clinical studies have shown that the villus thickness, intestinal cells, glucose transporters, enteric nerves, and gut microbiota and their metabolites in the duodenum undergo corresponding changes before and after the onset or treatment of T2D. These changes may be related to the pathogenesis of T2D. DMR procedure may produce beneficial glycemic and hepatic metabolic effects by regulating these changes.

CONCLUSION

The duodenum is an important metabolic signaling center, and limiting nutrient exposure to this critical region will have powerful metabolic benefits. The DMR procedure may regulate glycemic and hepatic parameters through various mechanisms, which needs to be further confirmed by a large number of animal and clinical studies.

Sleep duration of lactating mothers and its relationship with feeding pattern, milk macronutrients and related serum factors: A combined longitudinal cohort and cross-sectional study

Objective

Insufficient sleep is common in postpartum mothers. The main objectives of this study are to explore the sleep duration among Chinese lactating mothers and preliminarily investigate the relationship between sleep duration and feeding pattern. The secondary objectives are to investigate the relationships between sleep duration and milk macronutrients and between maternal-related indicators, including melatonin (MT), growth hormone (GH), ghrelin (GHRL), glucagon-like peptide-1 (GLP-1), prolactin (PRL), and cholecystokinin (CCK).

Methods

The present study comprises a longitudinal and a cross-sectional cohort from December 2019 to December 2021. Postpartum lactating women living in Shanghai were recruited through online and offline recruitment. The subjects were included in the longitudinal cohort or cross-sectional study based on their lactation period at the time of recruitment. The longitudinal cohort included a total of 115 mothers. Human milk and feeding pattern were measured and collected at 2–4 months and 5–7 months postpartum. At four predetermined follow-up time points, data on sleep duration was collected (at the time of recruitment, 2–4 months postpartum, 5–7 months postpartum, and 12–17 months postpartum). The cross-sectional study included 35 lactating mothers (2–12 months postpartum) who reported their sleep duration and provided blood samples. Mid-infrared spectroscopy (MIRS) method was used to analyze the macronutrients of breast milk, while MT, GH, GHRL, GLP-1, PRL, and CCK in maternal blood were determined by ELISA.

Results

The maternal sleep duration before pregnancy was 8.14 ± 1.18 h/d (n = 115), 7.27 ± 1.31 h/d (n = 113) for 2–4 months postpartum, 7.02 ± 1.05 h/d (n = 105) for 5–7 months postpartum, and 7.45 ± 1.05 h/d (n = 115) for 12–17 months postpartum. The incidence of insufficient sleep (<7 h/d) before pregnancy (12.17%) was significantly less than at any follow-up time after delivery (vs. 2–4 months postpartum, χ² = 10.101, p = 0.001; vs. 5–7 months postpartum, χ² = 15.281, p < 0.0001; vs. 12–17 months postpartum, χ² = 6.426, p = 0.011). The percentage of insufficient maternal sleep was highest at 5–7 months postpartum (34.29%). No significant difference was found between the incidence of insufficient sleep at 5–7 months postpartum, 2–4 months postpartum (29.20%, χ² = 0.650, p = 0.420), and 12–17 months postpartum (25.22%, χ² = 2.168, p = 0.141). At 2–4 months postpartum, the frequency of formula feeding per day is related to reduced maternal sleep duration (Standardization coefficient β = −0.265, p = 0.005, Adjusted R² = 0.061). At 2–4 months and 5–7 months postpartum, the relationship between macronutrients in breast milk and the mother's sleep duration was insignificant (all p > 0.05). Other than the positive correlation found between maternal GHRL and sleep duration (r = 0.3661, p = 0.0305), no significant relationship was observed between sleep duration and other indexes (all p > 0.05).

Conclusions

Postpartum mothers generally sleep less, but there is no correlation between insufficient sleep and the macronutrient content of breast milk. Formula feeding may be related to the mother's sleep loss, while breastfeeding (especially direct breastfeeding) may be related to increased maternal sleep duration. The findings suggest that sleep duration is related to maternal serum GHRL. More high-quality studies are needed to clarify the mechanism of these findings and provide a solid theoretical basis and support references for breastfeeding.