OBJECTIVE: This study sought to identify demographic, clinical, and genetic factors that may contribute to increased insulin resistance or worsening of glycaemic control in patients with T2DM.
SETTING: This prospective cohort study included 156 patients with T2DM and severe or acute hyperglycaemia who were treated with insulin at any medical ward of the National University of Malaysia Medical Centre.
METHOD: Insulin resistance was determined using the homeostatic model assessment-insulin resistance index. Glycaemic control during the episode of hyperglycaemia was assessed as the degree to which the patient achieved the target glucose levels. The polymerase chain reaction-restriction fragment length polymorphism method was used to identify polymorphisms in insulin receptor substrate (IRS) genes.
MAIN OUTCOME MEASURE: Identification of possible predictors (demographic, clinical, or genetic) for insulin resistance and glycaemic control during severe/acute hyperglycaemia.
RESULTS: A polymorphism in IRS1, r.2963 G>A (p.Gly972Arg), was a significant predictor of both insulin resistance [odds ratios (OR) 4.48; 95 % confidence interval (CI) 1.2-16.7; P = 0.03) and worsening of glycaemic control (OR 6.04; 95 % CI 0.6-64.6; P = 0.02). The use of loop diuretics (P < 0.05) and antibiotics (P < 0.05) may indirectly predict worsening of insulin resistance or glycaemic control in patients with severe/acute hyperglycaemia.
CONCLUSION: Clinical and genetic factors contribute to worsening of insulin resistance and glycaemic control during severe/acute hyperglycaemia in patients with T2DM. Early identification of factors that may influence insulin resistance and glycaemic control may help to achieve optimal glycaemic control during severe/acute hyperglycaemia.
METHODS AND RESULTS: Effects of GBR, brown rice, and white rice (WR) on fasting plasma glucose and selected genes were studied in type 2 diabetic rats. GBR reduced plasma glucose and weight more than metformin, while WR worsened glycemia over 4 weeks of intervention. Through nutrigenomic suppression, GBR downregulated gluconeogenic genes (Fbp1 and Pck1) in a manner similar to, but more potently than, metformin, while WR upregulated the same genes. Bioactives (gamma-amino butyric acid, acylated steryl glycoside, oryzanol, and phenolics) were involved in GBR's downregulation of both genes. Plasma glucose, Fbp1 and Pck1 changes significantly affected the weight of rats (p = 0.0001).
CONCLUSION: The fact that GBR downregulates gluconeogenic genes similar to metformin, but produces better glycemic control in type 2 diabetic rats, suggests other mechanisms are involved in GBR's antihyperglycemic properties. GBR as a staple could potentially provide enhanced glycemic control in type 2 diabetes mellitus better than metformin.
METHODS: Expression of TRAIL and TRAIL receptor in response to insulin and glucose was determined by polymerase chain reaction. Transcriptional activity was assessed using wild-type and site-specific mutations of the TRAIL promoter. Chromatin immunoprecipitation studies were performed. VSMC proliferation and apoptosis was measured.
RESULTS: Insulin and glucose exposure to VSMC for 24 h stimulated TRAIL mRNA expression. This was also evident at the transcriptional level. Both insulin- and glucose-inducible TRAIL transcriptional activity was blocked by dominant-negative specificity protein-1 (Sp1) overexpression. There are five functional Sp1-binding elements (Sp1-1, Sp1-2, Sp-5/6 and Sp1-7) on the TRAIL promoter. Insulin required the Sp1-1 and Sp1-2 sites, but glucose needed all Sp1-binding sites to induce transcription. Furthermore, insulin (but not glucose) was able to promote VSMC proliferation over time, associated with increased decoy receptor-2 (DcR2) expression. In contrast, chronic 5-day exposure of VSMC to 1 µg/mL insulin repressed TRAIL and DcR2 expression, and reduced Sp1 enrichment on the TRAIL promoter. This was associated with increased cell death.
CONCLUSIONS: The findings of the present study provide a new mechanistic insight into how TRAIL is regulated by insulin. This may have significant implications at different stages of diabetes-associated cardiovascular disease. Thus, TRAIL may offer a novel therapeutic solution to combat insulin-induced vascular pathologies.
METHODS: Two reviewers searched MEDLINE for studies of ≥12 weeks duration in adults with type 2 diabetes. The key search word was "gliclazide", filtered with "randomized controlled trial", "human" and "19+ years". Differences were explored in mean change in glycated hemoglobin (HbA(1c)) from baseline (primary outcome) and risk of hypoglycemia (secondary outcome) between gliclazide and other oral insulinotropic agents; and other sulfonylureas.
RESULTS: Nine out of 181 references reported primary outcomes, of which 7 reported secondary outcomes. Gliclazide lowered HbA1c more than other oral insulinotropic agents, with a weighted mean difference of -0.11% (95%, CI -0.19 to -0.03%, P=0.008, I(2)=60%), though not more than other sulfonylureas (-0.12%; 95%, CI -0.25 to 0.01%, P=0.07, I(2)=77%). Risk of hypoglycemia with gliclazide was not different to other insulinotropic agents (RR 0.85; 95%, CI 0.66 to 1.09, P=0.20, I(2)=61%) but significantly lower than other sulfonylureas (RR 0.47; 95%, CI 0.27 to 0.79, P=0.004, I(2)=0%).
CONCLUSION: Compared with other oral insulinotropic agents, gliclazide significantly reduced HbA1c with no difference regarding hypoglycemia risk. Compared with other sulfonylureas, HbA1c reduction with gliclazide was not significantly different, but hypoglycemia risk was significantly lower.