vitamin-k-1 and Vascular-Calcification

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; Matrix Gla Protein; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency

Chronic kidney disease (CKD) is commonly associated with vitamin K deficiency. Some of the serious complications of CKD are represented by cardiovascular disease (CVD) and skeletal fragility with an increased risk of morbidity and mortality. A complex pathogenetic link between hormonal and ionic disturbances, bone tissue and metabolism alterations, and vascular calcification (VC) exists and has been defined as chronic kidney disease-mineral and bone disorder (CKD-MBD). Poor vitamin K status seems to have a key role in the progression of CKD, but also in the onset and advance of both bone and cardiovascular complications. Three forms of vitamin K are currently known: vitamin K1 (phylloquinone), vitamin K2 (menaquinone), and vitamin K3 (menadione). Vitamin K plays different roles, including in activating vitamin K-dependent proteins (VKDPs) and in modulating bone metabolism and contributing to the inhibition of VC. This review focuses on the biochemical and functional characteristics of vitamin K vitamers, suggesting this nutrient as a possible marker of kidney, CV, and bone damage in the CKD population and exploring its potential use for promoting health in this clinical setting. Treatment strategies for CKD-associated osteoporosis and CV disease should include vitamin K supplementation. However, further randomized clinical studies are needed to assess the safety and the adequate dosage to prevent these CKD complications.

Topics: Bone and Bones; Cardiovascular Diseases; Chronic Kidney Disease-Mineral and Bone Disorder; Female; Humans; Male; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency

Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD). Both conditions are rising in incidence as well as prevalence, creating poor outcomes for patients and high healthcare costs. Recent data suggests CKD to be an independent risk factor for CVD. Accumulation of uremic toxins, chronic inflammation, and oxidative stress have been identified to act as CKD-specific alterations that increase cardiovascular risk. The association between CKD and cardiovascular mortality is markedly influenced through vascular alterations, in particular atherosclerosis and vascular calcification (VC). While numerous risk factors promote atherosclerosis by inducing endothelial dysfunction and its progress to vascular structural damage, CKD affects the medial layer of blood vessels primarily through VC. Ongoing research has identified VC to be a multifactorial, cell-mediated process in which numerous abnormalities like mineral dysregulation and especially hyperphosphatemia induce a phenotype switch of vascular smooth muscle cells to osteoblast-like cells. A combination of pro-calcifying stimuli and an impairment of inhibiting mechanisms like fetuin A and vitamin K-dependent proteins like matrix Gla protein and Gla-rich protein leads to mineralization of the extracellular matrix. In view of recent studies, intercellular communication pathways via extracellular vesicles and microRNAs represent key mechanisms in VC and thereby a promising field to a deeper understanding of the involved pathomechanisms. In this review, we provide an overview about pathophysiological mechanisms connecting CKD and CVD. Special emphasis is laid on vascular alterations and more recently discovered molecular pathways which present possible new therapeutic targets.

Topics: Animals; Atherosclerosis; Cardio-Renal Syndrome; Disease Models, Animal; Endothelium, Vascular; Extracellular Vesicles; Heart Disease Risk Factors; Humans; Incidence; Inflammation; Mice; MicroRNAs; Myocytes, Smooth Muscle; Rats; Renal Insufficiency, Chronic; Tunica Media; Vascular Calcification; Vitamin K 1; Vitamin K Deficiency

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.

Topics: Adult; Aged; Animals; Calcium-Binding Proteins; Dietary Supplements; Evidence-Based Medicine; Extracellular Matrix Proteins; Female; Humans; Kidney Failure, Chronic; Male; Matrix Gla Protein; Middle Aged; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamins

Vitamin K activates matrix Gla protein (MGP), a key inhibitor of vascular calcification. There is a high prevalence of sub-clinical vitamin K deficiency in patients with end-stage kidney disease.. A parallel randomized placebo-controlled pilot trial was designed to determine whether 10 mg of phylloquinone thrice weekly versus placebo modifies coronary artery calcification progression over 12 months in patients requiring hemodialysis with a coronary artery calcium score (CAC) ≥30 Agatston Units (ClinicalTrials.gov identifier NCT01528800). The primary outcome was feasibility (recruitment rate, compliance with study medication, study completion and adherence overall to study protocol). CAC score was used to assess calcification at baseline and 12 months. Secondary objectives were to explore the impact of phylloquinone on vitamin K-related biomarkers (phylloquinone, dephospho-uncarboxylated MGP and the Gla-osteocalcin to Glu-osteocalcin ratio) and events of clinical interest.. A total of 86 patients with a CAC score ≥30 Agatston Units were randomized to either 10 mg of phylloquinone or a matching placebo three times per week. In all, 69 participants (80%) completed the trial. Recruitment rate (4.4 participants/month) and medication compliance (96%) met pre-defined feasibility criteria of ≥4.17 and ≥90%, respectively. Patients randomized to phylloquinone for 12 months had significantly reduced levels of dephospho-uncarboxylated MGP (86% reduction) and increased levels of phylloquinone and Gla-osteocalcin to Glu-osteocalcin ratio compared with placebo. There was no difference in the absolute or relative progression of coronary artery calcification between groups.. We demonstrated that phylloquinone treatment improves vitamin K status and that a fully powered randomized trial may be feasible.

Topics: Calcium-Binding Proteins; Coronary Artery Disease; Extracellular Matrix Proteins; Humans; Osteocalcin; Pilot Projects; Renal Dialysis; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamin K 2

Coronary and aortic artery calcifications are generally slow to develop, and their burden predicts cardiovascular disease events. In patients with diabetes mellitus, arterial calcification is accelerated and calcification activity can be detected using 18F-sodium fluoride positron emission tomography (18F-NaF PET).. We aimed to determine whether vitamin K1 supplementation inhibits arterial calcification activity in individuals with diabetes mellitus.. This was a post hoc analysis of the ViKCoVaC (effect of Vitamin-K1 and Colchicine on Vascular Calcification activity in subjects with Diabetes Mellitus) double-blind randomized controlled trial conducted in Perth, Western Australia. Individuals with diabetes mellitus and established coronary calcification (coronary calcium score > 10), but without clinical coronary artery disease, underwent baseline 18F-NaF PET imaging, followed by oral vitamin K1 supplementation (10 mg/d) or placebo for 3 mo, after which 18F-NaF PET imaging was repeated. We tested whether individuals randomly assigned to vitamin K1 supplementation had reduced development of new 18F-NaF PET positive lesions within the coronary arteries and aorta.. In total, 149 individuals completed baseline and follow-up imaging studies. Vitamin K1 supplementation independently decreased the odds of developing new 18F-NaF PET positive lesions in the coronary arteries (OR: 0.35; 95% CI: 0.16, 0.78; P = 0.010), aorta (OR: 0.27; 95% CI: 0.08, 0.94; P = 0.040), and in both aortic and coronary arteries (OR: 0.28; 95% CI: 0.13, 0.63; P = 0.002).. In individuals with diabetes mellitus, supplementation with 10 mg vitamin K1/d may prevent the development of newly calcifying lesions within the aorta and the coronary arteries as detected using 18F-NaF PET. Further long-term studies are needed to test this hypothesis.This trial was registered at anzctr.org.au as ACTRN12616000024448.

Topics: Aged; Aorta; Coronary Vessels; Diabetes Mellitus; Diabetic Angiopathies; Dietary Supplements; Double-Blind Method; Female; Fluorine Radioisotopes; Follow-Up Studies; Humans; Male; Positron-Emission Tomography; Sodium Fluoride; Treatment Outcome; Vascular Calcification; Vitamin K 1; Western Australia

Patients on haemodialysis (HD) exhibit increased cardiovascular mortality associated with accelerated vascular calcification (VC). VC is influenced by inhibitors such as matrix Gla protein (MGP), a protein activated in the presence of vitamin K. HD patients exhibit marked vitamin K deficiency, and supplementation with vitamin K reduces inactive MGP levels in these patients. The VitaVasK trial analyses whether vitamin K1 supplementation affects the progression of coronary and aortic calcification in HD patients.. VitaVasK is a prospective, randomized, parallel group, multicentre trial (EudraCT No.: 2010-021264-14) that will include 348 HD patients in an open-label, two-arm design. After baseline multi-slice computed tomography (MSCT) of the heart and thoracic aorta, patients with a coronary calcification volume score of at least 100 will be randomized to continue on standard care or to receive additional supplementation with 5 mg vitamin K1 orally thrice weekly. Treatment duration will be 18 months, and MSCT scans will be repeated after 12 and 18 months. Primary end points are the progression of thoracic aortic and coronary artery calcification (calculated as absolute changes in the volume scores at the 18-month MSCT versus the baseline MSCT). Secondary end points comprise changes in Agatston score, mitral and aortic valve calcification as well as major adverse cardiovascular events (MACE) and all-cause mortality. VitaVask also aims to record MACE and all-cause mortality in the follow-up period at 3 and 5 years after treatment initiation. This trial may lead to the identification of an inexpensive and safe treatment or prophylaxis of VC in HD patients.

Topics: Antifibrinolytic Agents; Calcium-Binding Proteins; Coronary Artery Disease; Disease Progression; Extracellular Matrix Proteins; Humans; Matrix Gla Protein; Multicenter Studies as Topic; Patient Selection; Prospective Studies; Randomized Controlled Trials as Topic; Renal Dialysis; Tomography, X-Ray Computed; Vascular Calcification; Vitamin K 1

Haemodialysis patients suffer from accelerated vascular calcification. The vitamin K-dependent matrix Gla protein (MGP) is one of the most powerful inhibitors of vascular calcification. Haemodialysis patients have high levels of the inactive form of MGP (desphosphorylated-uncarboxylated-MGP, dp-uc-MGP) and may benefit from pharmacological doses of vitamin K2 (menaquinone) to improve the calcification inhibitory activity of MGP.. To determine the optimal dose of menaquinone-7 (MK-7) for MGP activation, 200 chronic haemodialysis patients were recruited to randomly receive 360, 720 or 1080 µg of MK-7 thrice weekly for 8 weeks. Dp-uc-MGP was measured at baseline and after 8 weeks. Dietary intake of vitamin K1 (phylloquinone) and menaquinone was estimated based on a detailed questionnaire.. At baseline, dp-uc-MGP was not associated with phylloquinone intake (P = 0.92), but correlated inversely with menaquinone intake (P = 0.023). MK-7 supplementation dose dependently reduced dp-uc-MGP. The levels decreased by 17, 33 and 46% in the respective groups. Drop-outs were mainly due to gastrointestinal side-effects related to the unpleasant smell of the tablets.. Chronic haemodialysis patients have high levels of inactive MGP, possibly related to a low dietary vitamin K intake. Pharmacological doses of MK-7 dose-dependently reduce dp-uc-MGP. Menaquinone supplementation may be a novel approach to prevent vascular calcifications in chronic haemodialysis patients.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Calcium-Binding Proteins; Dietary Supplements; Dose-Response Relationship, Drug; Extracellular Matrix Proteins; Female; Follow-Up Studies; Hemostatics; Humans; Male; Matrix Gla Protein; Middle Aged; Prognosis; Prospective Studies; Renal Dialysis; Single-Blind Method; Surveys and Questionnaires; Vascular Calcification; Vitamin K 1; Vitamin K 2; Vitamins; Young Adult

Animal studies have shown that vitamin K treatment reduced vascular calcification, but human data are limited.. We determined the association between vitamin K status and coronary artery calcium (CAC) progression in the Multi-Ethnic Study of Atherosclerosis by using a case-cohort design.. Serum phylloquinone (vitamin K1) was measured in 296 participants with extreme CAC progression and 561 randomly selected participants without extreme CAC progression; all subjects had baseline and follow-up CAC measures (mean follow-up: 2.5 y). A serum vitamin K1 concentration was considered low at <1.0 nmol/L (the distribution median). Outcomes were replicated by using post hoc per-protocol analyses of a vitamin K1 supplementation trial.. The OR (95% CI) for extreme CAC progression for subjects with low serum vitamin K1 compared with subjects without extreme CAC progression was 1.34 (0.94, 1.90; NS) when adjusted for demographics and confounders. A significant interaction between low vitamin K1 and antihypertension medication use was detected (P = 0.016). Hypertension medication users with low serum vitamin K1 were more likely to have extreme CAC progression than were medication users without extreme CAC progression [OR (95% CI): 2.37 (1.38, 4.09)]. In replication, baseline antihypertensive medication users in the supplementation group had less CAC progression than did those in the control group [adjusted mean ± SEM of the 3-y CAC change was +5 ± 20 Agatston units (AU) in the vitamin K1 group (n = 40) and +44 ± 13 AU in the placebo group (n = 49); P < 0.01].. Although the point estimate of our primary analysis suggests low serum vitamin K1 is associated with greater CAC progression, the difference was NS. Low serum vitamin K1 was significantly associated with CAC progression in antihypertension medication users, which, to our knowledge, is a novel finding conditionally replicated by using an independent sample. Intervention trials are needed to determine whether improving serum vitamin K1 reduces CAC progression, especially in hypertensive individuals. This trial was registered at clinicaltrials.gov as NCT00183001.

Topics: Aged; Atherosclerosis; Calcium; Cohort Studies; Coronary Artery Disease; Coronary Vessels; Dietary Supplements; Disease Progression; Double-Blind Method; Ethnicity; Female; Follow-Up Studies; Humans; Male; Middle Aged; Risk Factors; Vascular Calcification; Vitamin K 1

Hyperphosphataemia is strongly associated with cardiovascular disease and mortality. Recently, phosphate binders (PBs), which are used to bind intestinal phosphate, have been shown to bind vitamin K, thereby potentially aggravating vitamin K deficiency. This vitamin K binding by PBs may offset the beneficial effects of phosphate reduction in reducing vascular calcification (VC). Here we assessed whether combining PBs with vitamin K2 supplementation inhibits VC.. We performed 3/4 nephrectomy in rats, after which warfarin was given for 3 weeks to induce vitamin K deficiency. Next, animals were fed a high phosphate diet in the presence of low or high vitamin K2 and were randomized to either control or one of four different PBs for 8 weeks. The primary outcome was the amount of thoracic and abdominal aorta VC measured by high-resolution micro-computed tomography (µCT). Vitamin K status was measured by plasma MK7 levels and immunohistochemically analysed in vasculature using uncarboxylated matrix Gla protein (ucMGP) specific antibodies.. The combination of a high vitamin K2 diet and PB treatment significantly reduced VC as measured by µCT for both the thoracic (P = 0.026) and abdominal aorta (P = 0.023), compared with MK7 or PB treatment alone. UcMGP stain was significantly more present in the low vitamin K2-treated groups in both the thoracic (P < 0.01) and abdominal aorta (P < 0.01) as compared with high vitamin K2-treated groups. Moreover, a high vitamin K diet and PBs led to reduced vascular oxidative stress.. In an animal model of kidney failure with vitamin K deficiency, neither PB therapy nor vitamin K2 supplementation alone prevented VC. However, the combination of high vitamin K2 with PB treatment significantly attenuated VC.

Topics: Animals; Calcium-Binding Proteins; Extracellular Matrix Proteins; Female; Male; Models, Animal; Phosphates; Rats; Renal Dialysis; Renal Insufficiency; Vascular Calcification; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency; X-Ray Microtomography

Vitamin K is involved in the formation of coronary artery calcification which is an independent predictor of coronary heart disease. This study aims to explore the association between coronary artery calcification score and serum concentrations of vitamin K1, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) in middle-aged and elderly Chinese population.. A total of 116 patients who underwent CT coronary angiography were consecutively enrolled. Serum concentrations of vitamin K1, MK-4 and MK-7 were determined by high performance liquid chromatography tandem mass spectrometry. The relationships between coronary artery calcification score and serum vitamin K concentrations were analyzed.. Significantly lower serum vitamin K1 concentration was found in the patients with CACS > 400, comparing with the other CACS categories, respectively. Log (CACS + 1) was significantly higher in MK-4 < 0.05 ng/ml group compared with MK-4 ≥ 0.05 ng/ml group [2.03(0.21, 2.58) vs 1.31(0.00, 2.19), P < 0.05]. In subjects with established coronary calcification (defined as CACS > 10), vitamin K1 was found to be an independent factor contributing to higher CACS (r = -0.288, P = 0.013).. In this retrospective analysis, serum vitamin K1 and MK-4 concentrations were significantly lower in middle-aged and elderly cohorts with increasing calcification scores. The significant effect of vitamin K1 on CACS was only found in individuals who already had calcification. Whether the detection of circulating vitamin K in patients with preexisting coronary calcification could guide vitamin K supplementation needs further exploration.

Topics: Aged; Coronary Artery Disease; Humans; Middle Aged; Retrospective Studies; Vascular Calcification; Vitamin K; Vitamin K 1

Vascular calcification is an active process that increases cardiovascular disease (CVD) risk. There is still no consensus on an appropriate biomarker for vascular calcification. We reasoned that the biomarker for vascular calcification is the collection of all blood components that can be sensed and integrated into a calcification response by human vascular smooth muscle cells (hVSMCs).. We developed a new cell-based high-content assay, the BioHybrid assay, to measure in vitro calcification. The BioHybrid assay was compared with the o-Cresolphthalein assay and the T50 assay. Serum and plasma were derived from different cohort studies including chronic kidney disease (CKD) stages III, IV, V and VD (on dialysis), pseudoxanthoma elasticum (PXE) and other cardiovascular diseases including serum from participants with mild and extensive coronary artery calcification (CAC). hVSMCs were exposed to serum and plasma samples, and in vitro calcification was measured using AlexaFluor. The BioHybrid assay measured the kinetics of calcification in contrast to the endpoint o-Cresolphthalein assay. The BioHybrid assay was more sensitive to pick up differences in calcification propensity than the T50 assay as determined by measuring control as well as pre- and post-dialysis serum samples of CKD patients. The BioHybrid response increased with CKD severity. Further, the BioHybrid assay discriminated between calcification propensity of individuals with a high CAC index and individuals with a low CAC index. Patients with PXE had an increased calcification response in the BioHybrid assay as compared to both spouse and control plasma samples. Finally, vitamin K1 supplementation showed lower in vitro calcification, reflecting changes in delta Agatston scores. Lower progression within the BioHybrid and on Agatston scores was accompanied by lower dephosphorylated-uncarboxylated matrix Gla protein levels.. The BioHybrid assay is a novel approach to determine the vascular calcification propensity of an individual and thus may add to personalised risk assessment for CVD.

Topics: alpha-2-HS-Glycoprotein; Biomarkers; Calcium-Binding Proteins; Cardiovascular Diseases; Cells, Cultured; Extracellular Matrix Proteins; Fluorescent Dyes; Hematologic Tests; Humans; Kinetics; Matrix Gla Protein; Muscle, Smooth, Vascular; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K 1

Vascular calcification is commonly observed in atherosclerosis and diabetes. The renin-angiotensin II system is associated with the regulation of arterial stiffening. The aim of this study was to examine whether the angiotensin-converting enzyme inhibitors captopril attenuates artery calcification.. The rat model of arterial calcification was established by a combination of warfarin and vitamin K1. Two weeks after the induction of arterial calcification, captopril treatment was initiated. One week after captopril treatment, aortic arteries were examined to determine the calcification morphology and the connexin 43 expression. Matrix Gla protein (MGP), receptor activator of nuclear factor-κB ligand (RANKL) and extracellular regulated protein kinase (ERK) pathways were examined.. The morphology of the calcified arteries was significantly attenuated after captopril treatment. Consistently, captopril inhibited the increased connexin 43 expression and enhanced the decreased MGP expression in calcification arteries. Furthermore, captopril enhanced the decreased SM22 expression in calcified arteries by fluorescence assay. Finally, the calcification arteries increased the p38, p-ERK and RANKL expression, which were downregulated by captopril treatment.. We concluded that captopril attenuated the increased connexin 43 expression and enhanced the MGP and SM22 expression levels, which are associated with the inactivation of p-ERK, p38 and RANKL pathways in rat aortic arteries.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Arteries; Atherosclerosis; Calcium-Binding Proteins; Captopril; Connexin 43; Down-Regulation; Extracellular Matrix Proteins; Extracellular Signal-Regulated MAP Kinases; Male; Matrix Gla Protein; Microfilament Proteins; Muscle Proteins; RANK Ligand; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Up-Regulation; Vascular Calcification; Vascular Stiffness; Vitamin K 1; Warfarin

Vitamin K (VK) is a co-factor in the post-translational gamma glutamic carboxylation of Gla-proteins. VK-dependent coagulation factors are carboxylated in the liver by VK1. Osteocalcin and Matrix-Gla protein (MGP) are carboxylated in extrahepatic tissues by VK2. A model of VK deficiency would be suitable for studying extrahepatic Gla-proteins provided that severe bleeding is prevented.. The aim of this work was to adapt an established protocol of vascular calcification by warfarin-induced inactivation of MGP as a calcification inhibitor, in an attempt to create a broader state of subclinical VK deficiency and to verify its safety.. Two consecutive experiments, each lasting 4 weeks, were required to modify the dosing schedule of warfa-rin and VK1 and to adapt it to the Wistar rats used. The original high doses of warfarin used initially had to be halved and the protective dose of VK1 to be doubled, in order to avoid treatment-induced hemorrhagic deaths. The second experiment aimed to confirm the efficacy and safety of the modified doses. To verify the VK deficiency, blood vessels were examined histologically for calcium deposits and serum osteocalcin levels were mea-sured.. The original dosing schedule induced VK deficiency, manifested by arterial calcifications and dramatic changes in carboxyl-ated and uncarboxylated osteocalcin. The modified dosing regimen caused similar vascular calcification and no bleeding.. The modified protocol of carefully balanced warfarin and VK1 doses is an effective and safe way to induce subclinical VK deficiency that can be implemented to investigate VK-dependent proteins like osteocalcin.

Topics: Animals; Anticoagulants; Antifibrinolytic Agents; Arteries; Asymptomatic Diseases; Calcium-Binding Proteins; Carbon-Carbon Ligases; Disease Models, Animal; Extracellular Matrix Proteins; Matrix Gla Protein; Osteocalcin; Rats; Vascular Calcification; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency; Warfarin

Objective To investigate the effect of the angiotensin II receptor 1 (AT1R) blocker losartan on vascular calcification in rat aortic artery and explore the underlying mechanisms. Methods SD rats were divided randomly into control group, vascular calcification model group and treatment group. Vascular calcification models were made by subcutaneous injection of warfarin plus vitamin K1 for two weeks. Rats in the treatment group were subcutaneously injected with losartan (10 mg/kg) at the end of the first week and consecutively for one week. We observed the morphological changes by HE staining and the calcium deposition by Alizarin red staining in the artery vascular wall. The mRNA expressions of bone morphogenetic protein 2 (BMP2) and Runt-related transcription factor 2 (RUNX2) were analyzed by reverse transcription PCR. The BMP2 and RUNX2 protein expressions were determined by Western blotting. The apoptosis of smooth muscle cells (SMCs) were detected by TUNEL. The AT1R expression was tested by fluorescent immunohistochemistry. Results The aortic vascular calcification was induced by warfarin and vitamin K1. Compared with the vascular calcification model group, the mRNA and protein expressions of BMP2 and RUNX2 were significantly downregulated in the aorta in the losartan treatment group. Furthermore, the apoptosis of SMCs and the AT1R expression obviously decreased. Conclusion AT1R blocker losartan inhibits the apoptosis of SMCs and reduces AT1R expression; it downregulates the BMP2 and RUNX2 expressions in the vascular calcification process.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Apoptosis; Arteries; Blotting, Western; Bone Morphogenetic Protein 2; Core Binding Factor Alpha 1 Subunit; Gene Expression; Immunohistochemistry; Losartan; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Random Allocation; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Reverse Transcriptase Polymerase Chain Reaction; Vascular Calcification; Vitamin K 1; Warfarin

Decreased concentration of menaquinone-4 (MK-4) seems to be an important risk factor of vascular calcification in haemodialysis (HD) patients. Optimal dietary intake, as well as serum MK-4 reference range, in HD has not been determined, yet. The aim of the present study was to assess daily vitamin K1 and MK-4 intakes and their relation to serum MK-4 concentration in HD patients.. Daily vitamin K1 and MK-4, micro- and macronutrients and energy intakes were assessed using 3-day food diary completed by patients and serum MK-4 concentration was measured by HPLC [limit of quantification (LOQ): 0.055 ng/mL] in 85 HD patients (51 males) and 22 apparently healthy subjects.. Daily MK-4 intake was significantly lower (by 29%) among HD, while K1 consumption was similar in both groups. Daily MK-4 intake was associated with fat and protein consumption in HD (r=0.43, p<0.001 and r=0.33, p=0.004, respectively). In HD serum MK-4 concentration was more frequently below LOQ (in 41% HD and 5% controls, p<0.001) and in those HD with quantifiable values was lower than in the controls (by 42%). The correlations between MK-4 concentrations and both MK-4 and K1 daily intakes were weaker in HD (r=0.38 and r=0.30 respectively) than in the control group (r=0.47 and r=0.45, respectively). In multiple regression analysis the variability of serum MK-4 concentrations in HD patients was explained by its daily intake.. Decreased serum MK-4 concentration in HD patients is caused by lower dietary MK-4 intake, mainly due to diminished meat consumption, and in addition, probably reduced K1 conversion.

Topics: Case-Control Studies; Chromatography, High Pressure Liquid; Diet Records; Dietary Fats; Dietary Proteins; Energy Intake; Female; Hemostatics; Humans; Limit of Detection; Male; Middle Aged; Recommended Dietary Allowances; Reference Values; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K 1; Vitamin K 2

To investigate the association of plasma phylloquinone concentrations with coronary artery calcification (CAC) and vascular calcification.. In a prospective cohort of 508 postmenopausal women, plasma phylloquinone concentrations were measured by high-pressure liquid chromatography. Calcification was measured in the coronary arteries, aortic valve, mitral valve, and thoracic aorta by multidetector computed tomography. To combine these calcification scores, we dichotomized each of the 4 areas into present or absent. Because of the continuous measurement of CAC, we categorized this as calcification present if Agatston score was >0, and calcification score was calculated as the sum of the calcified areas. Multivariate-adjusted prevalence ratios and odds ratios were estimated using Poisson regression and multinomial logistic regression. After 8.5 years of follow-up, 22% of the women had no calcification, whereas 5% had calcification in all measured areas. Detectable phylloquinone concentrations were associated with increased CAC compared with nondetectable phylloquinone concentrations with a prevalence ratio of 1.34 (95% confidence interval, 1.01-1.77). When dividing women with detectable phylloquinone concentrations into low detectable (>0-0.70 nmol/L) and moderate to high detectable (>0.70 nmol/L) phylloquinone concentrations versus nondetectable phylloquinone concentrations, both were associated with increased CAC with a prevalence ratio of 1.32 (95% confidence interval, 0.99-1.76) and 1.36 (95% confidence interval, 1.02-1.81), respectively. Detectable phylloquinone concentrations were not associated with the number of calcified areas with an odds ratio(no versus ≥ 3 areas calcifications) of 1.60 (95% confidence interval, 0.65-3.99; P=0.31).. Detectable phylloquinone concentrations are not associated with reduced vascular calcification but seemed to be associated with an increased prevalence of CAC.

Topics: Aged; Aortic Diseases; Aortography; Biomarkers; Chromatography, High Pressure Liquid; Coronary Angiography; Coronary Artery Disease; Female; Healthy Volunteers; Humans; Logistic Models; Middle Aged; Multidetector Computed Tomography; Multivariate Analysis; Netherlands; Odds Ratio; Postmenopause; Prevalence; Prospective Studies; Risk Factors; Severity of Illness Index; Vascular Calcification; Vitamin K 1

Vascular calcification has emerged as an independent risk factor for cardiovascular morbidity and mortality, especially in chronic kidney disease. Deficiencies in calcium-regulatory proteins directly relate to development of calcifications. McCabe and colleagues report that vitamin K is a key regulator of vascular calcification, via carboxylation of vitamin K-dependent proteins such as matrix Gla protein. Knowledge about vitamin K status may propel therapeutic strategies to prevent and treat vascular calcification with high vitamin K supplementation.

Topics: Animals; Anticoagulants; Arteries; Dietary Supplements; Male; Renal Insufficiency, Chronic; Vascular Calcification; Vitamin K 1; Warfarin

Vascular calcification is an independent risk factor for cardiovascular disease. Once thought to be a passive process, vascular calcification is now known to be actively prevented by proteins acting systemically (fetuin-A) or locally (matrix Gla protein). Warfarin is a vitamin K antagonist, widely prescribed to reduce coagulation by inhibiting vitamin K-dependent coagulation factors. Recently, it became clear that vitamin K antagonists also affect vascular calcification by inactivation of matrix Gla protein. Here, we investigated functional cardiovascular characteristics in a mouse model with warfarin-induced media calcification.. DBA/2 mice received diets with variable concentrations of warfarin (0.03, 0.3, and 3 mg/g) with vitamin K1 at variable time intervals (1, 4, and 7 weeks). Von Kossa staining revealed that warfarin treatment induced calcified areas in both medial layer of aorta and heart in a dose- and time-dependent fashion, which could be inhibited by simultaneous vitamin K2 treatment. With ongoing calcification, matrix Gla protein mRNA expression decreased, and inactive matrix Gla protein expression increased. TdT-mediated dUTP-biotin nick end labeling-positive apoptosis increased, and vascular smooth muscle cell number was concomitantly reduced by warfarin treatment. On a functional level, warfarin treatment augmented aortic peak velocity, aortic valve-peak gradient, and carotid pulse-wave velocity.. Warfarin induced significant calcification with resulting functional cardiovascular damage in DBA/2 wild-type mice. The model would enable future researchers to decipher mechanisms of vascular calcification and may guide them in the development of new therapeutic strategies.

Topics: Animals; Anticoagulants; Antifibrinolytic Agents; Aorta; Apoptosis; Calcium; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Muscle, Smooth, Vascular; Pulsatile Flow; Risk Factors; Vascular Calcification; Vitamin K 1; Vitamin K 2; Warfarin

The leading cause of death in patients with chronic kidney disease (CKD) is cardiovascular disease, with vascular calcification being a key modifier of disease progression. A local regulator of vascular calcification is vitamin K. This γ-glutamyl carboxylase substrate is an essential cofactor in the activation of several extracellular matrix proteins that inhibit calcification. Warfarin, a common therapy in dialysis patients, inhibits the recycling of vitamin K and thereby decreases the inhibitory activity of these proteins. In this study, we sought to determine whether modifying vitamin K status, either by increasing dietary vitamin K intake or by antagonism with therapeutic doses of warfarin, could alter the development of vascular calcification in male Sprague-Dawley rats with adenine-induced CKD. Treatment of CKD rats with warfarin markedly increased pulse pressure and pulse wave velocity, as well as significantly increased calcium concentrations in the thoracic aorta (3-fold), abdominal aorta (8-fold), renal artery (4-fold), and carotid artery (20-fold). In contrast, treatment with high dietary vitamin K1 increased vitamin K tissue concentrations (10-300-fold) and blunted the development of vascular calcification. Thus, vitamin K has an important role in modifying mechanisms linked to the susceptibility of arteries to calcify in an experimental model of CKD.

Topics: Adenine; Animals; Anticoagulants; Arteries; Biomarkers; Blood Pressure; Dietary Supplements; Disease Models, Animal; Disease Progression; Male; Osteocalcin; Pulse Wave Analysis; Rats; Rats, Sprague-Dawley; Renal Insufficiency, Chronic; Time Factors; Vascular Calcification; Vitamin K 1; Vitamin K 2; Warfarin