Activation of inflammatory pathways in PBMCs linking type 2 diabetes in older adults without obesity

Effect of sitagliptin therapy on IL-29 and its associated signaling molecules in patients with type 2 diabetes mellitus

OBJECTIVE

The potential immunoregulatory capacity of sitagliptin on interleukin-29 (IL-29) and genes involved in its intracellular pathway were explored in type 2 diabetes mellitus (T2D).

MATERIALS AND METHODS

T2D patients treated with six months of sitagliptin (Sita+), patients not treated with sitagliptin (Sita-), and healthy controls (HCs) were included. IL-29 levels in the supernatant of stimulated mononuclear immune cells was determined with ELISA. The mRNA expression levels of IL-29, FOS, JUN, NF-AT2, NF-KB1, STAT1-2, IRF1, IRF3, IRF7, and IRF9 was assessed with real-time qPCR.

RESULTS

Increased protein and gene levels of IL-29 were observed in Sita- group compared to HCs (p < 0.001 and p = 0.026), while those levels were diminished in Sita+ group in comparison with Sita- group (p < 0.001 and p = 0.008). Expression of FOS, NF-AT2 and NF-KB1 in Sita- patients was higher than HCs (p = 0.018, p = 0.021, and p = 0.001). A significant decrease in expression of FOS, NF-AT2, and NF-KB1 was found in Sita+ group versus Sita- parients (p = 0.027, p = 0.003, and p = 0.002). In Sita- patients, IL-29 levels were correlated to glucose metabolism parameters including FPG and HbA1c (p < 0.05 for all).

CONCLUSION

Sitagliptin administration has a regulatory effect on the aggressive expression of IL-29 and its signaling molecules including FOS, NF-AT2 and NF-KB1 in T2D.

Muscle Quality in Relation to Prediabetes Phenotypes: A Population-Based Study With Mediation Analysis

CONTEXT

Prediabetes is associated with an increased risk of physical disability, yet no studies have assessed the extent to which muscle quality, a measure reflecting muscle functionality, was altered in prediabetes and its specific phenotype.

OBJECTIVE

We evaluated their associations in a general US population with mediation analysis.

METHODS

This was a cross-sectional study based on the National Health and Nutrition Examination Survey 2011-2014. Participants with prediabetes were stratified as having an isolated defect (impaired fasting glucose [IFG], impaired glucose tolerance [IGT], or impaired hemoglobin A1c [IA1c]), 2 defects (IFG + IGT, IFG + IA1c, or IGT + IA1c), or all defects (IFG + IGT + IA1c). Muscle quality was calculated as dominant grip strength divided by dominant arm muscle mass measured by dual-energy X-ray absorptiometry.

RESULTS

We included 2351 participants (938 with prediabetes and 1413 with normoglycemia). Despite higher grip strength and larger arm muscle mass, arm muscle quality was lower in prediabetes and all prediabetes phenotypes (except for IGT) than normoglycemia (all P < .04), and was unrelated to prediabetes awareness. Arm muscle quality was decreased and the odds of low arm muscle quality was increased in prediabetes with increasing numbers of glucometabolic defects (both P < .001), with insulin resistance being the predominant mediator. HbA1c-defined prediabetes (IA1c) had lower arm muscle quality and higher odds of low arm muscle quality than blood glucose-defined prediabetes (IFG, IGT, or IFG + IGT).

CONCLUSION

Muscle quality was impaired in prediabetes and its specific phenotype. Relative to blood glucose, elevated HbA1c might be a better predictor of reduced muscle quality.

Enhanced production of interleukin-29 and related genes are associated with T helper 1 cell parameters in patients with type 2 diabetes mellitus

OBJECTIVE

The production of interleukin (IL)-29 andthe genes related to IL-29 signaling pathway (STAT1, NF-κB, and NFATc1), and T helper (Th) 1 cells (T-bet, IFN-γ, TNF-α, and IL-2) were evaluated in type 2 diabetes mellitus (T2DM). Correlations between IL-29 and diabetes parameters, and between gene expression in IL-29 pathway and Th1 cells were also examined.

MATERIALS AND METHODS

41 newly diagnosed patients with T2DM and 41 healthy controls were recruited. CD4⁺ T cells were purifed and the production of IL-29 in the supernatant of anti- CD3 and anti- CD28 activated Th cells was detected using ELISA. The expression of IL-29- and Th1- related genes was determined with real-time PCR.

RESULTS

The secretion of IL-29 and the expression levels of NF-κB, NFATc1, IFN-γ, and TNF-α in Th cells were seen to be increased in diabetes persons compared to controls. Positive connections between IL-29 with hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) were found in diabetes persons. IL-29 was positively correlated with NFATc1 and TNF-α. NFATc1 was positively related to TNF-α.

CONCLUSION

Abnormal expression levels of IL-29- and Th1- related genes are linked with T2DM pathogenesis. IL-29 may amplify the expression of Th1-specific genes especially TNF-α by upregulating NFATc1 expression.

Changes in Insulin Sensitivity and Lipid Profile Markers Following Initial and Secondary Bouts of Multiple Eccentric Exercises

An acute bout of eccentric exercise affects insulin sensitivity and lipid profile, but how the magnitude of muscle damage affects them is not clear. We compared changes in blood insulin sensitivity and lipid markers after the first (EC1) and second (EC2) eccentric exercise bouts. Fifteen sedentary young men performed arm, leg and trunk muscle eccentric exercises, and repeated them 2 weeks later. Fasting blood samples were taken before, 2 h and 1–5 days after each exercise bout to analyze plasma creatine kinase (CK) activity, serum glucose (GLU), insulin, homeostasis model assessment (HOMA), triacylglycerols (TG), total (TC) and low- (LDLC) and high-density lipoprotein cholesterol (HDLC) concentrations as well as TC/HDLC ratio. Changes in these measures were compared between bouts and relationships to peak plasma CK activity were analyzed. Plasma CK activity increased (p < 0.05) after EC1 (peak: 101,668 ± 58,955 IU/L) but not after EC2. The magnitude of changes in GLU (peak after EC1: 26 ± 10% vs. EC2: 7 ± 6%), insulin (46 ± 27% vs. 15 ± 8%), HOMA (86 ± 48% vs. 24 ± 15%), TC (−20 ± 5% vs. −6 ± 4%), TG (−32 ± 11% vs. −6 ± 3%), LDHC (−47 ± 15% vs. −12 ± 9%), HDLC (35 ± 26% vs. 7 ± 4%), and TC/HDLC ratio (−139 ± 13% vs. −11 ± 7%) were significantly greater after EC1 than EC2. Peak plasma CK activity was significantly (p < 0.05) correlated with the peak changes in blood insulin sensitivity and lipid markers for the combined data of EC1 and EC2. These results suggest that the greater the magnitude of muscle damage, the greater the magnitude of changes in the insulin sensitivity to a negative direction and lipid markers to a positive direction.