Identification of functional differences between recombinant human α and β cardiac myosin motors

The myosin isoform composition of the heart is dynamic in health and disease and has been shown to affect contractile velocity and force generation. While different mammalian species express different proportions of α and β myosin heavy chain, healthy human heart ventricles express these isoforms in a ratio of about 1:9 (α:β) while failing human ventricles express no detectable α-myosin. We report here fast-kinetic analysis of recombinant human α and β myosin heavy chain motor domains. This represents the first such analysis of any human muscle myosin motor and the first of α-myosin from any species. Our findings reveal substantial isoform differences in individual kinetic parameters, overall contractile character, and predicted cycle times. For these parameters, α-subfragment 1 (S1) is far more similar to adult fast skeletal muscle myosin isoforms than to the slow β isoform despite 91% sequence identity between the motor domains of α- and β-myosin. Among the features that differentiate α- from β-S1: the ATP hydrolysis step of α-S1 is ~ten-fold faster than β-S1, α-S1 exhibits ~five-fold weaker actin affinity than β-S1, and actin·α-S1 exhibits rapid ADP release, which is >ten-fold faster than ADP release for β-S1. Overall, the cycle times are ten-fold faster for α-S1 but the portion of time each myosin spends tightly bound to actin (the duty ratio) is similar. Sequence analysis points to regions that might underlie the basis for this finding

The effects of coenzyme Q10 administration on glucose homeostasis parameters, lipid profiles, biomarkers of inflammation and oxidative stress in patients with metabolic syndrome

Background: Limited data are available indicating the effects of coenzyme Q10 (CoQ10) supplementation on metabolic status of patients with metabolic syndrome (MetS). Purpose: The present study was conducted to determine the effects of CoQ10 administration on glucose homeostasis parameters, lipid profiles, biomarkers of inflammation and oxidative stress among patients with MetS. Methods: This randomized, double-blind, placebo-controlled trial was performed among 60 overweight or obese and type 2 diabetes mellitus patients with coronary heart disease aged 40�85 years old. Participants were randomly allocated into two groups. Group A (n = 30) received 100 mg CoQ10 supplements and group B (n = 30) received placebo for 8 weeks. Fasting blood samples were taken at the beginning of the study and after 8-week intervention to quantify glucose homeostasis parameters, lipid profiles and biomarkers of inflammation and oxidative stress. Results: Compared with the placebo, CoQ10 supplementation resulted in a significant reduction in serum insulin levels (�2.1 ± 7.1 vs. +4.1 ± 7.8 µIU/mL, P = 0.002) and homeostasis model of assessment-insulin resistance (�0.7 ± 2.1 vs. +1.0 ± 2.0, P = 0.002) and homeostatic model assessment-beta cell function (�5.9 ± 22.2 vs. +15.9 ± 34.0, P = 0.005). In addition, patients who received CoQ10 supplements had a significant increase in plasma total antioxidant capacity (TAC) concentrations (+26.0 ± 105.0 vs. �162.2 ± 361.8 mmol/L, P = 0.008) compared with the placebo group. However, after adjustment for the baseline levels, age and baseline BMI, the effect on TAC levels (P = 0.08) disappeared. Additionally, compared with the placebo group, a significant positive trends in plasma glutathione (P = 0.06) and a significant reduction in malondialdehyde (P = 0.08) were seen among patients who received CoQ10 supplement. We did not observe any significant changes in fasting plasma glucose, lipid concentrations and inflammatory markers. Conclusions: Overall, daily intake of 100 mg CoQ10 supplements among patients with MetS for 8 weeks had beneficial effects on serum insulin levels, HOMA-IR, HOMA-B and plasma TAC concentrations. Clinical trial registration number: www.irct.ir: IRCT201502245623N35. © 2015, Springer-Verlag Berlin Heidelberg

The effects of Vitamin D, K and calcium co-supplementation on carotid intima-media thickness and metabolic status in overweight type 2 diabetic patients with CHD

This study was conducted to examine the effects of vitamin D, K and Ca co-supplementation on carotid intima-media thickness (CIMT) and metabolic status in overweight diabetic patients with CHD. This randomised, double-blind, placebo-controlled trial was conducted among sixty-six diabetic patients with CHD. Participants were randomly allocated into two groups to take either 5g vitamin D, 90 g vitamin K plus 500 mg Ca supplements (n 33) or placebo (n 33) twice a day for 12 weeks. Fasting blood samples were obtained at the beginning of the study and after the 12-week intervention period to determine related markers. Vitamin D, K and Ca co-supplementation resulted in a significant reduction in maximum levels of left CIMT (-0·04 (sd 0·22) v. +0·04 (sd 0·09) mm, P=0·02). Changes in serum vitamin D (+6·5 (sd 7·8) v. +0·4 (sd 2·2) ng/ml, P<0·001), Ca (+0·6 (sd 0·3) v. +0·1 (sd 0·1) mg/dl, P<0·001) and insulin concentrations (-0·9 (sd 3·1) v. +2·6 (sd 7·2) IU/ml, P=0·01), homoeostasis model for assessment of estimated insulin resistance (-0·4 (sd 1·2) v. +0·7 (sd 2·3), P=0·01), β-cell function (-2·1 (sd 9·0) v. +8·9 (sd 23·7), P=0·01) and quantitative insulin sensitivity check index (+0·007 (sd 0·01) v. -0·006 (sd 0·02), P=0·01) in supplemented patients were significantly different from those in patients in the placebo group. Supplementation resulted in significant changes in HDL-cholesterol (+2·7 (sd 7·0) v. -2·5 (sd 5·7) mg/dl, P=0·002), high-sensitivity C-reactive protein (-1320·1 (sd 3758·3) v. +464·0 (sd 3053·3) ng/ml, P=0·03) and plasma malondialdehyde concentrations (-0·4 (sd 0·5) v. -1·0 (sd 1·1) mol/l, P=0·007) compared with placebo. Overall, vitamin D, K and Ca co-supplementation for 12 weeks among diabetic patients with CHD had beneficial effects on maximum levels of left CIMT and metabolic status. The effect of vitamin D, K and Ca co-supplementation on maximum levels of left CIMT could be a chance finding. © The Authors 2016

Effects of smoking and gingival inflammation on salivary antioxidant capacity

WOS: 000235470500001PubMed ID: 16489940Aim: This study evaluated possible effects of smoking and gingival inflammation on salivary antioxidants in gingivitis patients. Methods: Twenty otherwise healthy gingivitis patients (10 self-reported smokers) and 20 periodontally and systemically healthy volunteer subjects were enrolled in the study. Whole saliva samples and full-mouth clinical periodontal recordings were obtained at baseline and one month following initial phase of treatment in gingivitis patients. Salivary cotinine, glutathione and ascorbic acid concentrations, and total antioxidant capacity were determined, and the data generated were tested by non-parametric tests. Results: Salivary cotinine measurements resulted in re-classification of three self-reported non-smokers as smokers. Smoker patients revealed significantly higher probing depths but lower bleeding values than non-smoker patients (p = 0.044 and 0.001, respectively). Significant reductions in clinical recordings were obtained in non-smoker (all p 0.05). Conclusions: Within the limits of this study, neither smoking nor gingival inflammation compromised the antioxidant capacity of saliva in systemically healthy gingivitis patients