Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin K is a nutrient that was originally identified as an essential factor for blood coagulation. Recently, vitamin K has emerged as a potential protector against osteoporosis, atherosclerosis, and hepatocarcinoma. Accumulated evidence indicates that subclinical non-hemostatic vitamin K deficiency in extrahepatic tissues, particularly in bone and possibly in vasculature, exists widely in the otherwise healthy adult population. Vitamins K1 and K2 have been shown to exert protective effects against osteoporosis, although it is important that the beneficial effects will be further confirmed by large-scale, randomized, clinical trials. Increasing evidence implicates a role for vitamin K in calcification of arteries and atherogenesis. Moreover, the therapeutic potential of vitamin K2 as an antihepatoma drug has recently been highlighted. Most of the new biological functions of vitamin K in bone, vasculature, and hepatoma cells are considered attributable to promotion of gamma-carboxylation of glutamic acid residues in vitamin K-dependent proteins, which is shared by vitamins K1 and K2. In contrast, vitamin K2-specific, gamma-carboxylation-unrelated functions have also been demonstrated. Thus, biological differences between vitamins K1 and K2 and potential involvement of gamma-carboxylation-independent actions in the new roles of vitamin K remain open issues. Molecular bases of coagulation-unrelated pleiotropic actions of vitamin K and its implications in human health deserve further investigations.
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PMID:Pleiotropic actions of vitamin K: protector of bone health and beyond? 1681 98

Vitamin K is a nutrient originally identified as an essential factor for blood coagulation. Accumulated evidence indicates that subclinical non-hemostatic vitamin K deficiency in extrahepatic tissues, particularly in bone, exists widely in the otherwise healthy adult population. Both vitamin K1 and K2 have been shown to exert protective effects against osteoporosis. The new biological functions of vitamin K in bone are considered to be attributable, at least in part, to promotion of gamma-carboxylation of glutamic acid residues in vitamin K-dependent proteins, which is shared by both vitamins K1 and K2. A recent evidence of significant correlation between polymorphism of gamma-glutamyl carboxylase gene and bone mineral density supports the role of gamma-carboxylation-dependent actions of vitamin K. In contrast, vitamin K2-specific,gamma-carboxylation-unrelated functions have recently attracted scientific attention. Recent findings of vitamin K2-specific transactivation of steroid and xenobiotic receptor (SXR/PXR) may lead to new research avenue. The impact of genotype of apoE, a major vitamin K transporter, on ostepporosis as well as Alzheimer disease and atherosclerosis, raises a question whether vitamin K is involved in the pathogenesis of these diseases. Molecular bases of coagulation-unrelated pleiotropic actions of vitamin K and its implications in bone health deserve further investigations.
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PMID:[Genomic approaches to bone and joint diseases. New insights into molecular mechanisms underlying protective effects of vitamin K on bone health]. 1824 93

Uremic subjects, in addition to accelerated atherosclerosis, develop diffuse media vascular calcification (VC) which, in turn, is associated with increased vascular stiffness and mortality risk. Two sets of risk factors for VC can be considered: passive deposition of calcium-phosphate and active transformation of vascular smooth muscle cells into osteoblastic- like cells. The former is linked with the metabolic imbalance in divalent ions that affects renal patients at any stage of the disease; the latter is secondary to a recently discovered mechanism of cellular trans-differentiation caused by deranged local concentration of divalent ions. Also, the role of inhibitors of calcification is under investigation. These include circulating or local, substances like fetuin, matrix GLA protein or osteoprotegerin. Their biologic importance is supported by the occurrence of calcification in transgenic animals lacking these factors. Accordingly, VC is a complex biologic and incompletely understood process that deserves further research, in order to develop specific therapeutic strategies. In general, once established, these calcifications are not considered to be reversible; therefore, prevention is the main treatment option. With this aim, in uremic patients it is now recommended to adopt restricted ranges of serum concentrations for calcium, phosphate and parathyroid hormone which are associated with a lower rate of calcification. To target these recommended ranges, new drugs, like selective vitamin D receptor activators, calcium sensing receptor modulators and calcium free intestinal phosphate binders, have been introduced. Moreover new possible pathogenetic pathways are considered (e.g. vitamin K deficiency). Further, in patients with calciphylaxis, the most severe form of VC, experimental therapies are suggested, with drugs like sodium thiosulphate or bisphosphonates. Drugs capable of reversing the process of trans-differentiation from osteoblast-like to vascular smooth muscle cells could be developed in the future.
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PMID:Treatment of cardiovascular calcification in uremia. 2182 4

Atherosclerosis is the main cause of morbidity and mortality in the general population, and premature death in patients with chronic kidney disease (CKD) especially dialysis ones. Besides the typical cardiovascular risk factors there is a considerable vascular calcification of intima media in these patients. Vitamin K - dependent proteins play an essential role in the pathogenesis of mineral and bone disorders related to CKD, including vascular calcification. Vitamin K is a family of vitamins, varying in the number of isoprenoid groups (saturated or unsaturated) connected into 2-methyl-1,4-naphthoquinone ring in C3 position. Vitamin K-dependent proteins require carboxylation (VKDPs) for biological activation. The coagulant factors are the most well-known VKDPs, but the role of the other proteins, like Matrix Gla Protein (MGP), Growth Arrest Specific Gene 6 (Gas-6) and osteocalcin has been recently discovered. MGP prevents vascular calcification and Gas-6 affects vascular smooth muscle cell apoptosis and movement. Carboxylation of osteocalcin promotes bone formation. Additionally vitamin K increases proliferation of osteoblasts and apoptosis of osteoclasts, influencing on bone remodeling. There is few studies indicating for decreased consumption of vitamin K in the general population. The restrictive diet recommended for dialysis patients additionally diminishes its daily supply, increasing the chance for vitamin K deficiency in this population. Clinical consequences of inhibition of epoxide reductase by generally used anticoagulants, that inhibiting vitamin K cycle and preventing gamma-carboxylation of Gla proteins, in the peripheral tissue is hardly known. This paper summaries the state of the art knowledge focused on the role of vitamin K in mineral and bone metabolism disorders in CKD patients.
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PMID:[Vitamin K, bone metabolism and vascular calcification in chronic kidney disease]. 2233 14

Vitamin K is essential for the synthesis of proteins belonging to the Gla-protein family. To the members of this family belong four blood coagulation factors, which all are exclusively formed in the liver. The importance of vitamin K for hemostasis is demonstrated from the fact that vitamin K-deficiency is an acute, life-threatening condition due to excessive bleeding. Other members of the Gla-protein family are osteocalcin, matrix Gla-protein (MGP), and Gas6 that play key functions in maintaining bone strength, arterial calcification inhibition, and cell growth regulation, respectively. In total 17 Gla-proteins have been discovered at this time. Recently, it was observed that the dietary vitamin K requirement for the synthesis of the coagulation factors is much lower than for that of the extra-hepatic Gla-proteins. This forms the basis of the triage theory stating that during poor dietary supply, vitamins are preferentially utilized for functions that are important for immediate survival. This explains why in the healthy population all clotting factors are synthesized in their active form, whereas the synthesis of other Gla-proteins is sub-optimal in non-supplemented subjects. Prolonged sub-clinical vitamin K deficiency is a risk factor for osteoporosis, atherosclerosis, and cancer. Present recommendations for dietary intake are based on the daily dose required to prevent bleeding. Accumulating scientific data suggests that new, higher recommendations for vitamin K intake should be formulated.
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PMID:Vitamin K: the effect on health beyond coagulation - an overview. 2248 24

Vascular calcification occurs when calcium accumulates in the intima (associated with atherosclerosis) and/or media layers of the vessel wall. Coronary artery calcification (CAC) reflects the calcium burden within the intima and media of the coronary arteries. In population-based studies, CAC independently predicts cardiovascular disease (CVD) and mortality. A preventive role for vitamin K in vascular calcification has been proposed based on its role in activating matrix Gla protein (MGP), a calcification inhibitor that is expressed in vascular tissue. Although animal and in vitro data support this role of vitamin K, overall data from human studies are inconsistent. The majority of population-based studies have relied on vitamin K intake to measure status. Phylloquinone is the primary dietary form of vitamin K and available supplementation trials, albeit limited, suggest phylloquinone supplementation is relevant to CAC. Yet observational studies have found higher dietary menaquinone, but not phylloquinone, to be associated with less calcification. Vascular calcification is highly prevalent in certain patient populations, especially in those with chronic kidney disease (CKD), and it is plausible vitamin K may contribute to reducing vascular calcification in patients at higher risk. Subclinical vitamin K deficiency has been reported in CKD patients, but studies linking vitamin K status to calcification outcomes in CKD are needed to clarify whether or not improving vitamin K status is associated with improved vascular health in CKD. This review summarizes the available evidence of vitamin K and vascular calcification in population-based studies and clinic-based studies, with a specific focus on CKD patients.
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PMID:Vitamin K status and vascular calcification: evidence from observational and clinical studies. 2251 23

Background: A low vitamin K status is common in patients on haemodialysis, and this is considered one of the reasons for the accelerated atherosclerosis in these patients. The vitamin is essential in activation of the protein Matrix Gla Protein (MGP), and the inactive form, dp-ucMGP, is used to measure vitamin K status. The purpose of this study was to investigate possible underlying causes of low vitamin K status, which could potentially be low intake, washout during dialysis or inhibited absorption capacity. Moreover, the aim was to investigate whether the biomarker dp-ucMGP is affected in these patients. Method: Vitamin K intake was assessed by a Food Frequency Questionnaire (FFQ) and absorption capacity by means of D-xylose testing. dp-ucMGP was measured in plasma before and after dialysis, and phylloquinine (vitamin K1) and dp-ucMGP were measured in the dialysate. Changes in dp-ucMGP were measured after 14 days of protein supplementation. Results: All patients had plasma dp-ucMGP above 750 pmol/L, and a low intake of vitamin K. The absorption capacity was normal. The difference in dp-ucMGP before and after dialysis was -1022 pmol/L (p < 0.001). Vitamin K1 was not present in the dialysate but dp-ucMGP was at a high concentration. The change in dp-ucMGP before and after protein supplementation was -165 pmol/L (p = 0.06). Conclusion: All patients had vitamin K deficiency. The reason for the low vitamin K status is not due to removal of vitamin K during dialysis or decreased absorption but is plausibly due to a low intake of vitamin K in food. dp-ucMGP is washed out during dialysis, but not affected by protein intake to a clinically relevant degree.
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PMID:Causes of Vitamin K Deficiency in Patients on Haemodialysis. 3282 43