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American Journal of Transplantation :... Apr 2023Vitamin K deficiency is common among kidney transplant recipients (KTRs) and likely contributes to progressive vascular calcification and stiffness. In this... (Randomized Controlled Trial)
Randomized Controlled Trial
Effect of vitamin K supplementation on serum calcification propensity and arterial stiffness in vitamin K-deficient kidney transplant recipients: A double-blind, randomized, placebo-controlled clinical trial.
Vitamin K deficiency is common among kidney transplant recipients (KTRs) and likely contributes to progressive vascular calcification and stiffness. In this single-center, randomized, double-blind, placebo-controlled trial, we aimed to investigate the effects of vitamin K supplementation on the primary end point, serum calcification propensity (calciprotein particle maturation time, T50), and secondary end points arterial stiffness (pulse wave velocity [PWV]) and vitamin K status in 40 vitamin K-deficient KTRs (plasma dephosphorylated uncarboxylated matrix Gla protein [dp-ucMGP] ≥500 pmol/L). Participants (35% female; age, 57 ± 13 years) were randomized 1:1 to vitamin K2 (menaquinone-7, 360 μg/day) or placebo for 12 weeks. Vitamin K supplementation had no effect on calcification propensity (change in T50 vs baseline +2.3 ± 27.4 minutes) compared with placebo (+0.8 ± 34.4 minutes; P = .88) but prevented progression of PWV (change vs baseline -0.06 ± 0.26 m/s) compared with placebo (+0.27 ± 0.43 m/s; P = .010). Vitamin K supplementation strongly improved vitamin K status (change in dp-ucMGP vs baseline -385 [-631 to -269] pmol/L) compared with placebo (+39 [-188 to +183] pmol/L; P < .001), although most patients remained vitamin K-deficient. In conclusion, vitamin K supplementation did not alter serum calcification propensity but prevented progression of arterial stiffness, suggesting that vitamin K has vascular effects independent of calciprotein particles. These results set the stage for longer-term intervention studies with vitamin K supplementation in KTRs. TRIAL REGISTRY: EU Clinical Trials Register (EudraCT Number: 2019-004906-88) and the Dutch Trial Register (NTR number: NL7687).
Topics: Humans; Female; Adult; Middle Aged; Aged; Male; Vitamin K; Vascular Stiffness; Kidney Transplantation; Pulse Wave Analysis; Vitamin K 2; Dietary Supplements; Double-Blind Method
PubMed: 36695702
DOI: 10.1016/j.ajt.2022.12.015 -
Cellular and Molecular Life Sciences :... Aug 2006Phytanic acid is a branched-chain fatty acid that accumulates in a variety of metabolic disorders. High levels of phytanic acid found in patients can exceed the... (Review)
Review
Phytanic acid is a branched-chain fatty acid that accumulates in a variety of metabolic disorders. High levels of phytanic acid found in patients can exceed the millimolar range and lead to severe symptoms. Degradation of phytanic acid takes place by alpha-oxidation inside the peroxisome. A deficiency of its breakdown, leading to elevated levels, can result from either a general peroxisomal dysfunction or from a defect in one of the enzymes involved in alpha-oxidation. Research on Refsum disease, belonging to the latter group of disorders and characterized by a deficiency of the first enzyme of alpha-oxidation, has extended our knowledge of phytanic acid metabolism and pathology of the disease greatly over the past few decades. This review will centre on this research on phytanic acid: its origin, the mechanism by which its alpha-oxidation takes place, its role in human disease and the way it is produced from phytol.
Topics: Aldehyde Oxidoreductases; Chondrodysplasia Punctata, Rhizomelic; Humans; Oxidation-Reduction; Peroxisomal Disorders; Peroxisomes; Phytanic Acid; Phytol; Protein Transport; Refsum Disease
PubMed: 16799769
DOI: 10.1007/s00018-005-5463-y -
Atencion Primaria Oct 2022Two important topics about children and adolescents in our primary care activity are presented in this update document: tobacco smoking prevention in adolescence and...
Two important topics about children and adolescents in our primary care activity are presented in this update document: tobacco smoking prevention in adolescence and prophylaxis with vitamin K to prevent the hemorrhagic disease of the newborn.
Topics: Infant, Newborn; Humans; Adolescent; Child; Smoking Prevention; Vitamin K
PubMed: 36435589
DOI: 10.1016/j.aprim.2022.102441 -
Nutrients Jan 2022Vitamin K (VK) plays many important functions in the body. The most important of them include the contribution in calcium homeostasis and anticoagulation. Vascular... (Review)
Review
Vitamin K (VK) plays many important functions in the body. The most important of them include the contribution in calcium homeostasis and anticoagulation. Vascular calcification (VC) is one of the most important mechanisms of renal pathology. The most potent inhibitor of this process-matrix Gla protein (MGP) is VK-dependent. Chronic kidney disease (CKD) patients, both non-dialysed and hemodialysed, often have VK deficiency. Elevated uncarboxylated matrix Gla protein (ucMGP) levels indirectly reflected VK deficiency and are associated with a higher risk of cardiovascular events in these patients. It has been suggested that VK intake may reduce the VC and related cardiovascular risk. Vitamin K intake has been suggested to reduce VC and the associated cardiovascular risk. The role and possibility of VK supplementation as well as the impact of anticoagulation therapy on VK deficiency in CKD patients is discussed.
Topics: Anticoagulants; Blood Coagulation; Bone and Bones; Calcium; Calcium-Binding Proteins; Cardiovascular Diseases; Extracellular Matrix Proteins; Humans; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency; Matrix Gla Protein
PubMed: 35057443
DOI: 10.3390/nu14020262 -
Journal of Pharmaceutical and... May 2019Vitamin K is an essential nutrient in the body and involved in numerous physiological and pathophysiological functions. Both the lack and surplus of vitamin K can put... (Review)
Review
Vitamin K is an essential nutrient in the body and involved in numerous physiological and pathophysiological functions. Both the lack and surplus of vitamin K can put human health at risk. Therefore, it becomes necessary to monitor vitamin K concentrations in different biomatrices through establishing sensitive and specific analytical methods. This review collectively describes an updated overview of the sample pretreatment methodologies and methods for quantitative determination of vitamin K that have been used in last two decades. High Performance Liquid Chromatography (HPLC) is commonly utilized as a standard for separation of vitamin K in combination with different detection including spectroscopic, spectrometric, fluorometric and mass spectroscopy. Recent progress in sample pretreatment technologies and quantitation methodologies have enhanced the ability to identify and quantitate vitamin K in biomatrices to further advance our understanding of the role of this vitamin in human health and disease.
Topics: Animals; Chromatography, High Pressure Liquid; Humans; Mass Spectrometry; Vitamin K
PubMed: 30861405
DOI: 10.1016/j.jpba.2019.03.006 -
Journal of Nutritional Science and... 2022Vitamins are a family of micronutrients comprising 13 groups of organic compounds, of which vitamin B1 was identified first, approximately 110 y ago. Deficiency of each... (Review)
Review
Vitamins are a family of micronutrients comprising 13 groups of organic compounds, of which vitamin B1 was identified first, approximately 110 y ago. Deficiency of each vitamin results in specific symptoms, such as neuropathy, dermatitis, diarrhea, dementia, pernicious anemia, scurvy, blindness, rickets, and bleeding. Almost all vitamins can modulate the functions of enzymes and/or other proteins involved in the formation of bone and soft tissues, generation of energy, and regulation of homeostasis via specific vitamin-protein interactions. In addition to the well-known physiological roles of vitamins, novel modes of action of vitamins have been elucidated. These new functions could contribute to extending healthy life expectancy by preventing and curing lifestyle-related diseases. In this mini-review, we introduce the functional properties of three vitamins, vitamin B3 (niacin), biotin, and vitamin K, for the prevention of age-related diseases.
Topics: Vitamins; Vitamin A; Vitamin K; Thiamine; Life Style
PubMed: 36437027
DOI: 10.3177/jnsv.68.S8 -
Journal of Nutritional Science and... 2022We have adopted the following four topics: 1) dietary phosphorus management in chronic kidney disease (CKD) patients, 2) inadequate nutrient intakes in Filipino...
We have adopted the following four topics: 1) dietary phosphorus management in chronic kidney disease (CKD) patients, 2) inadequate nutrient intakes in Filipino schoolchildren and adolescents, 3) clinical and societal implications of vitamin insufficiency, and 4) zinc transporters. Vitamins and minerals play essential roles in health promotion in clinical and societal perspectives with marked advances in understanding the mechanism underlying such effects.
Topics: Adolescent; Humans; Child; Vitamins; Vitamin A; Minerals; Vitamin K; Phosphorus
PubMed: 36437023
DOI: 10.3177/jnsv.68.S70 -
Synthesis of Naphthoquinone Derivatives: Menaquinones, Lipoquinones and Other Vitamin K Derivatives.Molecules (Basel, Switzerland) Sep 2020Menaquinones are a class of isoprenoid molecules that have important roles in human biology and bacterial electron transport, and multiple methods have been developed... (Review)
Review
Menaquinones are a class of isoprenoid molecules that have important roles in human biology and bacterial electron transport, and multiple methods have been developed for their synthesis. These compounds consist of a methylnaphthoquinone (MK) unit and an isoprene side chain, such as found in vitamin K (phylloquinone), K, and other lipoquinones. The most common naturally occurring menaquinones contain multiple isoprene units and are very hydrophobic, rendering it difficult to evaluate the biological activity of these compounds in aqueous assays. One way to overcome this challenge has been the application of truncated MK-derivatives for their moderate solubility in water. The synthesis of such derivatives has been dominated by Friedel-Crafts alkylation with BF∙OEt. This attractive method occurs over two steps from commercially available starting materials, but it generally produces low yields and a mixture of isomers. In this review, we summarize reported syntheses of both truncated and naturally occurring MK-derivatives that encompass five different synthetic strategies: Nucleophilic ring methods, metal-mediated reactions, electrophilic ring methods, pericyclic reactions, and homologation and side chain extensions. The advantages and disadvantages of each method are discussed, identifying methods with a focus on high yields, regioselectivity, and stereochemistry leading to a detailed overview of the reported chemistry available for preparation of these compounds.
Topics: Alkylation; Catalysis; Naphthoquinones; Oxidation-Reduction; Vitamin K; Vitamin K 2
PubMed: 33003459
DOI: 10.3390/molecules25194477 -
Molecules (Basel, Switzerland) Aug 2023Food supplementation formulations refer to products that are designed to provide additional nutrients to the diet. Vitamins, dietary fibers, minerals and other... (Review)
Review
Food supplementation formulations refer to products that are designed to provide additional nutrients to the diet. Vitamins, dietary fibers, minerals and other functional compounds (such as antioxidants) are concentrated in dietary supplements. Specific amounts of dietary compounds are given to the body through food supplements, and these include as well so-called non-essential compounds such as secondary plant bioactive components or microbial natural products in addition to nutrients in the narrower sense. A significant social challenge represents how to moderately use the natural resources in light of the growing world population. In terms of economic production of (especially natural) bioactive molecules, ways of white biotechnology production with various microorganisms have recently been intensively explored. In the current review other relevant dietary supplements and natural substances (e.g., vitamins, amino acids, antioxidants) used in production of dietary supplements formulations and their microbial natural production via fermentative biotechnological approaches are briefly reviewed. Biotechnology plays a crucial role in optimizing fermentation conditions to maximize the yield and quality of the target compounds. Advantages of microbial production include the ability to use renewable feedstocks, high production yields, and the potential for cost-effective large-scale production. Additionally, it can be more environmentally friendly compared to chemical synthesis, as it reduces the reliance on petrochemicals and minimizes waste generation. Educating consumers about the benefits, safety, and production methods of microbial products in general is crucial. Providing clear and accurate information about the science behind microbial production can help address any concerns or misconceptions consumers may have.
Topics: Antioxidants; Fermentation; Vitamins; Dietary Supplements; Vitamin A; Vitamin K
PubMed: 37630272
DOI: 10.3390/molecules28166020 -
BMJ (Clinical Research Ed.) Jul 1996
Topics: Erythroblastosis, Fetal; Humans; Infant, Newborn; Leukemia; Neoplasms; Vitamin K; Vitamin K Deficiency
PubMed: 8696177
DOI: 10.1136/bmj.313.7051.179