menaquinone-6 and Bone-Diseases

Patients with CKD are at an increased risk of developing vascular calcification (VC) and bone complications which translate into a higher morbidity and mortality. The dephosphorylated and uncarboxylated matrix Gla protein (dp-ucMGP) is considered to be an indicator of vitamin K2 status and correlates with markers of VC. It is activated by γ-glutamyl carboxylase that converts inactive MGP into an active form, and vitamin K2 is a cofactor of this reaction. The active form of MGP is a known inhibitor of arterial wall calcification and plays an important role in bone turnover. Recent studies show poor vitamin K2 status in CKD patients. We aimed to review the literature for the association between vitamin K2 status and calcification and bone disease risk and the efficacy of vitamin K2 supplementation in CKD population.. Most CKD patients, including those on renal replacement therapy, have vitamin K2 deficiency. The dp-ucMGP level, a marker of vitamin K2 status, is decreased by vitamin K2 supplementation in CKD patients, but there is no unequivocal proof that it influences arterial calcification progression and bone complications. Key Messages: CKD population are at risk of vitamin K deficiency. Supplementation of vitamin K2 is safe and improves the serum markers of its deficiency. There is lack of strong evidence that vitamin K2 supplementation slows progression of calcification or reduces the frequency of bone complications. More prospective studies are needed.

Topics: Animals; Bone Diseases; Dietary Supplements; Humans; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K 2; Vitamin K Deficiency

Vitamins D and K are lipid-phase nutrients that are pleiotropic - endowed with versatile homeostatic capacities at the organ, tissue, and cellular levels. Their metabolic and physiologic roles overlap considerably, as evidenced in the bone and cardiovascular systems. Vitamin D₃ (cholecalciferol, D₃) is the prehormone for the vitamin D endocrine system. Vitamin D₃ undergoes initial enzymatic conversion to 25-hydroxyvitamin D (25D, calcidiol), then to the seco-steroid hormone 1alpha, 25-dihydroxyvitamin D (1,25D, calcitriol). Beyond its endocrine roles in calcium homeostasis, 1,25D likely has autocrine, paracrine, and intracrine effects. At least 17 tissues likely synthesize 1,25D, and 35 carry the vitamin D receptor (VDR). Vitamin D functional deficiency is widespread in human populations. Vitamin K₁ (phylloquinone) is more abundant in foods but less bioactive than the vitamin K₂ menaquinones (especially MK-4, menatetrenone). Menadione (vitamin K₃) has minimal K activity. Vitamin K compounds undergo oxidation-reduction cycling within the endoplasmic reticulum membrane, donating electrons to activate specific proteins via enzymatic gamma-carboxylation of glutamate groups before being enzymatically re-reduced. Warfarin inhibits this vitamin K reduction, necessitating K supplementation during anticoagulation therapy. Along with coagulation factors (II, VII, IX, X, and prothrombin), protein C and protein S, osteocalcin (OC), matrix Gla protein (MGP), periostin, Gas6, and other vitamin K-dependent (VKD) proteins support calcium homeostasis, facilitate bone mineralization, inhibit vessel wall calcification, support endothelial integrity, are involved in cell growth control and tissue renewal, and have numerous other effects. This review updates vitamin D and K skeletal and cardiovascular benefits and evidence for their synergy of action.

Topics: Bone and Bones; Bone Density; Bone Diseases; Calcification, Physiologic; Cardiovascular Diseases; Cardiovascular System; Cholecalciferol; Fractures, Bone; Humans; Nutritional Physiological Phenomena; Osteoblasts; Osteocytes; Vitamin D Deficiency; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K 3; Vitamin K Deficiency

Thalassemic osteopathy (TOSP) has emerged as a topic of interest, as the optimized transfusion regimens and iron chelations has markedly improved the survival of the patients suffering from thalassemia major (TM) and increased the life expectancy. The aim of this prospective monocentric pilot study was to investigate the effects of a dietary supplement with vitamin K2 (50 mcg menaquinone-7) and vitamin D (5 mcg calcitriol) on the patients with TOSP. Twenty children (12 girls, 8 boys; age varied from 3 to 18 y) with β TM, who underwent regular blood transfusion and iron chelation therapy, were enrolled in this study and investigated at the initial, sixth, and 12th month of the treatment. We detected a significant improvement in the bone mineral density and Z-score at the lumbar spine area of the patients at the sixth and 12th month of the treatment, especially in the prepubertal group. We also found a decrease in the ratio of undercarboxylated osteocalcin to carboxylated osteocalcin, however, this was not found to be significant. Although the natural course of TOSP is worsening or at least stabilizing, our pilot study demonstrated that vitamin K2 and calcitriol combination clearly has a positive effect on the bone mineral density of the children with TM during a 1-year period. Supplementation of menaquinone-7 instead of drugs is an augmented physiological intake and seems a beneficial alternative for the treatment of TOSP. Further studies on a large number of participants are necessary to highlight the effect of vitamin K2 on TOSP.

Topics: Absorptiometry, Photon; Adolescent; beta-Thalassemia; Bone and Bones; Bone Density; Bone Density Conservation Agents; Bone Diseases; Calcitriol; Chelation Therapy; Child; Female; Humans; Iron Chelating Agents; Male; Pilot Projects; Transfusion Reaction; Vitamin K 2

A low level of intact parathyroid hormone (PTH) is an indicator of adynamic bone disease in hemodialysis patients, and is associated with a significant increase of all-cause mortality. Thus, effective treatment for adynamic bone disease is required. We previously investigated the effect of vitamin K₂ on adynamic bone disease. In this study, we assessed the efficacy of oral vitamin K₂ in a controlled trial.. Forty hemodialysis patients with low intact PTH levels (<100 pg/ml) were randomly divided into two groups, which were a vitamin K₂ group receiving oral menatetrenone (45 mg/day) for 1 year and a control group without vitamin K₂. Venous blood samples were collected at baseline and during the study for measurement of bone metabolism parameters.. Thirty-three patients completed follow-up. There was a significant increase of the serum intact osteocalcin level after 1 month of vitamin K₂ administration. Serum levels of intact PTH, bone alkaline phosphatase, and cross-linked N-terminal telopeptide of type I collagen increased significantly after 12 months in the vitamin K₂ group. The serum osteoprotegerin level was decreased after 12 months in the vitamin K₂ group, but the change was not significant.. Vitamin K₂ therapy improves bone remodeling in hemodialysis patients with a low intact PTH level.

Topics: Aged; Alkaline Phosphatase; Biomarkers; Bone Diseases; Bone Remodeling; Collagen Type I; Female; Humans; Male; Middle Aged; Osteocalcin; Parathyroid Hormone; Peptides; Renal Dialysis; Statistics, Nonparametric; Vitamin K 2