| 2. |
- Pikilidou, M. I., et al.
(author)
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Insulin sensitivity increase after calcium supplementation and change in intraplatelet calcium and sodium-hydrogen exchange in hypertensive patients with Type 2 diabetes
- 2009
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In: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 26:3, s. 211-219
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Journal article (peer-reviewed)abstract
- To investigate the effect of oral calcium (Ca2+) supplementation on insulin sensitivity measured by the euglycaemic hyperinsulinaemic clamp, intraplatelet cationic concentration of Ca2+ ([Ca2+](i)) and the transmembrane sodium-hydrogen exchanger (NHE) activity in erythrocytes in subjects with Type 2 diabetes and hypertension. In this parallel randomized controlled single-blinded trial, 31 patients were allocated to receive either 1500 mg of Ca2+ orally, daily (n = 15) or no treatment (n = 16) for 8 weeks. At baseline and at the end of the 8-week period insulin sensitivity, [Ca2+](i) and the first isoform of NHE (NHE-1) activity were measured. At the end of the study, subjects who received Ca2+ supplementation showed higher insulin sensitivity (Delta M-value 0.32 +/- 0.5 mmol/min P < 0.05) and lower [Ca2+](i) (125.0 +/- 24.7 to 80.4 +/- 10.6 nmol/l, P < 0.05, mean +/- sem) and NHE-1 activity (79.5 +/- 10.0 to 52.1 +/- 6.4 mmol Na/l red cell/h, P < 0.05). None of the above parameters were changed in the control group. Simple regression analysis demonstrated the change in [Ca2+](i) significantly determined insulin sensitivity change (beta = -0.36, P < 0.05). Oral Ca2+ supplementation improves insulin sensitivity in patients with Type 2 diabetes and hypertension. These changes are likely to be mediated by changes in intracellular ionic Ca2+. NHE-1 activity was also reduced after Ca2+ supplementation but its role in insulin sensitivity requires further investigation.
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| 3. |
- Sarafidis, P. A., et al.
(author)
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Validity and reproducibility of HOMA-IR, 1/HOMA-IR, QUICKI and McAuley's indices in patients with hypertension and type II diabetes
- 2007
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In: Journal of Human Hypertension. - : Springer Science and Business Media LLC. - 1476-5527 .- 0950-9240. ; 21:9, s. 709-716
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the validity and reliability of homeostasis model assessment-insulin resistance (HOMA-IR) index, its reciprocal (1/HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and McAuley's index in hypertensive diabetic patients. In 78 patients with hypertension and type II diabetes glucose, insulin and triglyceride levels were determined after a 12-h fast to calculate these indices, and insulin sensitivity (IS) was measured with the hyperinsulinemic euglycemic clamp technique. Two weeks later, subjects had again their glucose, insulin and triglycerides measured. Simple and multiple linear regression analysis were applied to assess the validity of these indices compared to clamp IS and coefficients of variation between the two visits were estimated to assess their reproducibility. HOMA-IR index was strongly and inversely correlated with the basic IS clamp index, the M-value (r = 0.572, P < 0.001), M- value normalized with subjects' body weight or fat-free mass and every other clamp-derived index. 1/HOMA-IR and QUICKI indices were positively correlated with the M- value (r = 0.342, P < 0.05 and r = 0.456, P < 0.01, respectively) and the rest clamp indices. McAuley's index generally presented less strong correlations ( r = 0.317, P < 0.05 with M- value). In multivariate analysis, HOMA-IR was the best fit of clampderived IS. Coefficients of variation between the two visits were 23.5% for HOMA-IR, 19.2% for 1/HOMA-IR, 7.8% for QUICKI and 15.1% for McAuley's index. In conclusion, HOMA- IR, 1/HOMA-IR and QUICKI are valid estimates of clamp-derived IS in patients with hypertension and type II diabetes, whereas the validity of McAuley's index needs further evaluation. QUICKI displayed better reproducibility than the other indices.
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