Duodenal L cell density correlates with features of metabolic syndrome and plasma metabolites

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.

SMALL INTESTINAL L CELL DENSITY IN PATIENTS WITH SEVERE OBESITY AFTER ROUX-EN-Y GASTRIC BYPASS

BACKGROUND:

Enteroendocrine L cells can be found in the entire gastrointestinal tract and their incretins act on glycemic control and metabolic homeostasis. Patients with severe obesity and type 2 diabetes mellitus may have lower density of L cells in the proximal intestine.

AIMS:

This study aimed to analyze the density of L cells in the segments of the small intestine in the late postoperative of Roux-en-Y gastric bypass in diabetic patients with standardization of 60 cm in both loops, alimentary and biliopancreatic.

METHODS:

Immunohistochemistry analysis assays were made from intestinal biopsies in three segments: gastrointestinal anastomosis (GIA= Point A), enteroenteral anastomosis (EEA= Point B= 60 cm distal to the GIA) and 60 cm distal to the enteroenteral anastomosis (Point C).

RESULTS:

A higher density of L cells immunostaining the glucagon-1 peptide was observed in the distal portion (Point C) when compared to the more proximal portions (Points A and B).

CONCLUSIONS:

The concentration of L cells is higher 60 cm distal to enteroenteral anastomosis when comparing to proximal segments and may explain the difference in intestinal lumen sensitization and enterohormonal response after Roux-en-Y gastric bypass.

[The study of tryptophan metabolite concentrations in blood serum and fecal extracts from obese children]

We found that changes in the concentrations of tryptophan metabolites in the blood serum and in the intestinal contents are one of the mechanisms for the formation of metabolic coupling in the system "macroorganism-intestinal microbiota", which undergoes significant changes in the development of obesity. Although blood kynurenine remained basically unchanged in obese children we found an increase in some of its serum metabolites: anthranilic, kynurenic and xanthurenic acids. It is noteworthy that in the analysis of fecal matter in obese children, revealed a 2-fold increase in the level of kynurenine while the concentration of kynurenine pathway metabolites corresponded to the level of the group of healthy children. This may indicate the metabolic activation of the microbiota associated with the intestinal mucosa. This is also supported by the absence of statistically significant differences in the concentration of indole in healthy children and in obese children in fecal analyses, and a significant increase in the concentration of indole-3-lactate and indole-3-acetate in the blood serum of obese children.