Association Between Bone Mineral Density and Pancreatic β-Cell Function in Elderly Men and Postmenopausal Women

Evaluation of hemorheological parameters as biomarkers of calcium metabolism and insulin resistance in postmenopausal women

BACKGROUND

Calcium, vitamin D and insulin resistance are linked to osteoporosis and cardiovascular disease in menopause.

OBJECTIVE

Determine if hemorheological parameters related to blood viscosity in microcirculation are linked to calcium metabolism and insulin resistance in menopause.

METHODS

25-Hydroxyvitamin D (25(OH)D)), 1, 25-dihydroxyvitamin D3 (1, 25(OH)2D), parathyroid hormone, ionized calcium, glucose, insulin and hemoglobin A1c were measured in blood from 43 volunteers. Red blood cells (RBC) aggregation, RBC deformability and whole blood viscosity were also performed.

RESULTS

25(OH)D showed a positive correlation with RBC deformability 0.60 Pa. Subjects with 25(OH)D≤29.00 ng/mL had lower RBC deformability 0.60 Pa, and higher RBC aggregation and higher HOMA-IR. Ionized calcium showed a negative correlation with RBC aggregation. Subjects with ionized calcium ≤1.24 mmol/L showed higher RBC aggregation. There was a positive correlation between HOMA-IR and RBC aggregation and HOMA-IR showed a negative correlation with RBC deformability 0.30 Pa. Subjects with HOMA-IR <1.80 showed lower RBC aggregation and higher RBC deformability at 0.30 Pa, 0.60 Pa, 1.20 Pa, 3.0 Pa and 6.0 Pa.

CONCLUSION

Low 25(OH)D, low ionized calcium and high HOMA-IR are related to impaired hemorheology in menopause. RBC aggregation and deformability can be used as biomarkers of calcium metabolism and insulin resistance in menopause.

The Role of Vitamin K in Humans: Implication in Aging and Age-Associated Diseases

As human life expectancy is rising, the incidence of age-associated diseases will also increase. Scientific evidence has revealed that healthy diets, including good fats, vitamins, minerals, or polyphenolics, could have antioxidant and anti-inflammatory activities, with antiaging effects. Recent studies demonstrated that vitamin K is a vital cofactor in activating several proteins, which act against age-related syndromes. Thus, vitamin K can carboxylate osteocalcin (a protein capable of transporting and fixing calcium in bone), activate matrix Gla protein (an inhibitor of vascular calcification and cardiovascular events) and carboxylate Gas6 protein (involved in brain physiology and a cognitive decline and neurodegenerative disease inhibitor). By improving insulin sensitivity, vitamin K lowers diabetes risk. It also exerts antiproliferative, proapoptotic, autophagic effects and has been associated with a reduced risk of cancer. Recent research shows that protein S, another vitamin K-dependent protein, can prevent the cytokine storm observed in COVID-19 cases. The reduced activation of protein S due to the pneumonia-induced vitamin K depletion was correlated with higher thrombogenicity and possibly fatal outcomes in COVID-19 patients. Our review aimed to present the latest scientific evidence about vitamin K and its role in preventing age-associated diseases and/or improving the effectiveness of medical treatments in mature adults ˃50 years old.

Combination of Aronia, Red Ginseng, Shiitake Mushroom and Nattokinase Potentiated Insulin Secretion and Reduced Insulin Resistance with Improving Gut Microbiome Dysbiosis in Insulin Deficient Type 2 Diabetic Rats

The combination of freeze-dried aronia, red ginseng, ultraviolet-irradiated shiitake mushroom and nattokinase (AGM; 3.4:4.1:2.4:0.1) was examined to evaluate its effects on insulin resistance, insulin secretion and the gut microbiome in a non-obese type 2 diabetic animal model. Pancreatectomized (Px) rats were provided high fat diets supplemented with either (1) 0.5 g AGM (AGM-L), (2) 1 g AGM (AGM-H), (3) 1 g dextrin (control), or (4) 1 g dextrin with 120 mg metformin (positive-control) per kg body weight for 12 weeks. AGM (1 g) contained 6.22 mg cyanidin-3-galactose, 2.5 mg ginsenoside Rg3 and 244 mg β-glucan. Px rats had decreased bone mineral density in the lumbar spine and femur and lean body mass in the hip and leg compared to the normal-control and AGM-L and AGM-H prevented the decrease. Visceral fat mass was lower in the control group than the normal-control group and its decrease was smaller with AGM-L and AGM-H. HOMA-IR was lower in descending order of the control, positive-control, AGM-L, AGM-H and normal-control groups. Glucose tolerance deteriorated in the control group and was improved by AGM-L and AGM-H more than in the positive-control group. Glucose tolerance is associated with insulin resistance and insulin secretion. Insulin tolerance indicated insulin resistance was highly impaired in diabetic rats, but it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Insulin secretion capacity, measured by hyperglycemic clamp, was much lower in the control group than the normal-control group and it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Diabetes modulated the composition of the gut microbiome and AGM prevented the modulation of gut microbiome. In conclusion, AGM improved glucose metabolism by potentiating insulin secretion and reducing insulin resistance in insulin deficient type 2 diabetic rats. The improvement of diabetic status alleviated body composition changes and prevented changes of gut microbiome composition.