Heterogeneity in the effect of marked weight loss on metabolic function in women with obesity

Changes in insulin sensitivity and gut peptides 8 and 52 weeks after bariatric surgery or low-calorie diet

The endocrine consequences of weight loss by bariatric surgery (BS) and caloric restriction are not fully understood but contribute to variable improvements in insulin sensitivity and cardiometabolic health. This study compared changes in insulin sensitivity and plasma concentrations of gut peptides 8 weeks and 1 year after BS and a low-calorie diet (LCD). Nineteen female patients with obesity self-selected BS (gastric bypass [n = 5] or sleeve gastrectomy [n = 7]) or LCD (n = 7) in this parallel-arm, prospective observational study. We assessed insulin sensitivity via a two-step hyperinsulinemic-euglycemic clamp (20 and 80 mU/min/m2 insulin). Plasma glucose, insulin, and gut peptides were measured around a mixed meal tolerance test (400 kcal). Visual analogue scales (VAS) were used to rate subjective appetite sensations. All assessments were conducted at baseline and after 8 weeks and 1 year of intervention. Whole-body insulin sensitivity was unchanged 8 weeks after the intervention. One year after surgery, insulin sensitivity at both 20 and 80 mU/m2/min insulin infusion doses increased with BS weight loss (-33.8% ± 1.4% body weight) but was unchanged in LCD with small weight loss (-3.7% ± 2.0% body weight). Postprandial total PYY increased more following BS while total and acylated ghrelin decreased more following BS compared to LCD. Hunger decreased and fullness increased with BS compared to LCD (p = .037; p = .010, respectively). Insulin sensitivity was improved only 1 year after BS, despite significant weight loss after 8 weeks. Changes in gut peptides after BS paralleled reduced hunger and increased fullness. Most improvements in cardiometabolic health were related to weight loss.

Phosphatidylethanolamine (18:2e/18:2) may inhibit adipose tissue wasting in patients with cancer cachexia by increasing lysophosphatidic acid receptor 6

BACKGROUND

Cancer associated cachexia is characterized by the significant loss of adipose tissue, leading to devastating weight loss and muscle wasting in the majority of cancer patients. The effects and underlying mechanisms of degradation metabolites on adipocytes in cachectic patients remain poorly understood. To address this knowledge gap, we conducted a comprehensive study combining lipidomic analysis of subcutaneous and visceral adipose tissue with transcriptomics data from the database to investigate the mechanisms of lipid regulation in adipocytes.

METHODS

We collected subcutaneous and visceral adipose tissue samples from cachectic and noncachectic cancer patients. Lipidomic analysis was performed to identify differentially expressed lipids in both types of adipose tissue. Additionally, transcriptomics data from the GEO database were analyzed to explore gene expression patterns in adipocytes. Bioinformatics analysis was employed to determine the enrichment of differentially expressed genes in specific pathways. Furthermore, molecular docking studies were conducted to predict potential protein targets of specific lipids, with a focus on the PI3K-Akt signaling pathway. Western blot analysis was used to validate protein levels of the identified target gene, lysophosphatidic acid receptor 6 (LPAR6), in subcutaneous and visceral adipose tissue from cachectic and noncachectic patients.

RESULTS

Significant lipid differences in subcutaneous and visceral adipose tissue between cachectic and noncachectic patients were identified by multivariate statistical analysis. Cachectic patients exhibited elevated Ceramides levels and reduced CerG2GNAc1 levels (P < 0.05). A total of 10 shared lipids correlated with weight loss and IL-6 levels, enriched in Sphingolipid metabolism, GPI-anchor biosynthesis, and Glyceropholipid metabolism pathways. LPAR6 expression was significantly elevated in both adipose tissues of cachectic patients (P < 0.05). Molecular docking analysis indicated strong binding of Phosphatidylethanolamine (PE) (18:2e/18:2) to LPAR6.

CONCLUSIONS

Our findings suggest that specific lipids, including PE(18:2e/18:2), may mitigate adipose tissue wasting in cachexia by modulating the expression of LPAR6 through the PI3K-Akt signaling pathway. The identification of these potential targets and mechanisms provides a foundation for future investigations and therapeutic strategies to combat cachexia. By understanding the underlying lipid regulation in adipocytes, we aim to develop targeted interventions to ameliorate the devastating impact of cachexia on patient outcomes and quality of life. Nevertheless, further studies and validation are warranted to fully elucidate the intricate mechanisms involved and translate these findings into effective clinical interventions.

Induction of remission in diabetes by lowering blood glucose

As diabetes continues to grow as major health problem, there has been great progress in understanding the important role of pancreatic beta-cells in its pathogenesis. Diabetes develops when the normal interplay between insulin secretion and the insulin sensitivity of target tissues is disrupted. With type 2 diabetes (T2D), glucose levels start to rise when beta-cells are unable to meet the demands of insulin resistance. For type 1 diabetes (T1D) glucose levels rise as beta-cells are killed off by autoimmunity. In both cases the increased glucose levels have a toxic effect on beta-cells. This process, called glucose toxicity, has a major inhibitory effect on insulin secretion. This beta-cell dysfunction can be reversed by therapies that reduce glucose levels. Thus, it is becoming increasingly apparent that an opportunity exists to produce a complete or partial remission for T2D, both of which will provide health benefit.