P1645VITAMIN K DEPENDENT PROTEINS AFTER KIDNEY TRANSPLANTATION: RESULTS FROM PROSPECTIVE STUDY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Maria Fusaro ◽  
Pascale Khairallah ◽  
Andrea Aghi ◽  
Mario Plebani ◽  
Martina Zaninotto ◽  
...  
Keyword(s):  
Kidney Transplantation ◽  
Prospective Study ◽  
Vascular Calcification ◽  
Vitamin K ◽  
Matrix Gla Protein ◽  
Bone Gla Protein ◽  
Vitamin K Deficiency ◽  
Prospective Data ◽  
K Deficiency ◽  
The Impact

Abstract Background and Aims Two Vitamin K-dependent proteins (VDKPs) link bone and vasculature in CKD-MBD: Bone Gla Protein (BGP) and Matrix Gla Protein (MGP). In ESKD, Vitamin K deficiency is highly prevalent and leads to increased levels of inactive VKDPs (undercaboxylated (ucBGP and dephosphorylated (dp)-uMGP), which are linked to greater risk of fractures and severity of vascular calcification. We hypothesized that kidney transplantation (KT) would improve Vitamin K status and lower levels of inactive VKDPs. Method Between 2014-2017, we conducted a study in 34 patients to assess changes in VKDPs during the 1st year of KT. In a specialized lab we determined VKDPs pre- and 1-year post-KT: total BGP, uc BGP, total MGP, and dp-uc MGP. We determined the prevalence of Vitamin K deficiency based on levels of uc BGP and dp-uc MGP. Results Our cohort had a mean +/- SD age of 48+/-14 years, 32% were female and 97% were Caucasian. 1 year post-KT, there was a decrease in the levels of all VKDPs and the prevalence of Vitamin K deficiency (Table 1 and Figure 1). Patients with greatest severity of Vitamin K deficiency pre-KT had the largest decreases of inactive VDKPs post-KT. Conclusion KT was associated with improvement in Vitamin K status as manifested by decreased levels of inactive VKDPs. These are the first prospective data on VKDPs in CKD patients pre- and post-KT. Studies are needed to assess the impact of improvement in VKDP status after KT on CKD-MBD outcomes.

scholarly journals Functional vitamin K insufficiency, vascular calcification and mortality in advanced chronic kidney disease: A cohort study

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247623
Author(s):  
Lu Dai ◽  
Longkai Li ◽  
Helen Erlandsson ◽  
Armand M. G. Jaminon ◽  
Abdul Rashid Qureshi ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Vascular Calcification ◽  
Vitamin K ◽  
Matrix Gla Protein ◽  
Vitamin K Deficiency ◽  
Increased Risk ◽  
Ckd Stage ◽  
All Cause Mortality ◽  
K Deficiency

Patients with chronic kidney disease (CKD) suffer from vitamin K deficiency and are at high risk of vascular calcification (VC) and premature death. We investigated the association of functional vitamin K deficiency with all-cause mortality and whether this association is modified by the presence of VC in CKD stage 5 (CKD G5). Plasma dephosphorylated-uncarboxylated matrix Gla-protein (dp-ucMGP), a circulating marker of functional vitamin K deficiency, and other laboratory and clinical data were determined in 493 CKD G5 patients. VC was assessed in subgroups by Agatston scoring of coronary artery calcium (CAC) and aortic valve calcium (AVC). Backward stepwise regression did not identify dp-ucMGP as an independent determinant of VC. During a median follow-up of 42 months, 93 patients died. Each one standard deviation increment in dp-ucMGP was associated with increased risk of all-cause mortality (sub-hazard ratio (sHR) 1.17; 95% confidence interval, 1.01–1.37) adjusted for age, sex, cardiovascular disease, diabetes, body mass index, inflammation, and dialysis treatment. The association remained significant when further adjusted for CAC and AVC in sub-analyses (sHR 1.22, 1.01–1.48 and 1.27, 1.01–1.60, respectively). In conclusion, functional vitamin K deficiency associates with increased mortality risk that is independent of the presence of VC in patients with CKD G5.

Vitamin K deficiency: an emerging player in the pathogenesis of vascular calcification and an iatrogenic consequence of therapies in advanced renal disease

2020 ◽  
Vol 319 (4) ◽  
pp. F618-F623
Author(s):  
David S. Levy ◽  
Rickinder Grewal ◽  
Thu H. Le
Keyword(s):  
Bone Metabolism ◽  
Vascular Calcification ◽  
Vitamin K ◽  
Hospital Admissions ◽  
Fibroblast Growth Factor 23 ◽  
Vitamin K Deficiency ◽  
Increased Risk ◽  
K Deficiency ◽  
Human Aortic Valve

Vascular calcification is a known complication of chronic kidney disease (CKD). The prevalence of vascular calcification in patients with non-dialysis-dependent CKD stages 3–5 has been shown to be as high as 79% ( 20 ). Vascular calcification has been associated with increased risk for mortality, hospital admissions, and cardiovascular disease ( 6 , 20 , 50 , 55 ). Alterations in mineral and bone metabolism play a pivotal role in the pathogenesis of vascular calcification in CKD. As CKD progresses, levels of fibroblast growth factor-23, parathyroid hormone, and serum phosphorus increase and levels of 1,25-(OH)2 vitamin D decrease. These imbalances have been linked to the development of vascular calcification. More recently, additional factors have been found to play a role in vascular calcification. Matrix G1a protein (MGP) in its carboxylated form (cMGP) is a potent inhibitor of vascular calcification. Importantly, carboxylation of MGP is dependent on the cofactor vitamin K. In patients with CKD, vitamin K deficiency is prevalent and is exacerbated by warfarin, which is frequently used for anticoagulation. Insufficient bioavailability of vitamin K reduces the amount of cMGP available, and, therefore, it may lead to increased risk of vascular calcification. In vitro studies have shown that in the setting of a high-phosphate environment and vitamin K antagonism, human aortic valve interstitial cells become calcified. In this article, we discuss the pathophysiological consequence of vitamin K deficiency in the setting of altered mineral and bone metabolism, its prevalence, and clinical implications in patients with CKD.

scholarly journals Association of the Inactive Circulating Matrix Gla Protein with Vitamin K Intake, Calcification, Mortality, and Cardiovascular Disease: A Review

2019 ◽  
Vol 20 (3) ◽  
pp. 628 ◽  
Author(s):  
Stefanos Roumeliotis ◽  
Evangelia Dounousi ◽  
Theodoros Eleftheriadis ◽  
Vassilios Liakopoulos
Keyword(s):  
Cardiovascular Disease ◽  
Renal Function ◽  
Vitamin K ◽  
Serum Levels ◽  
Matrix Gla Protein ◽  
Biologically Active ◽  
Vitamin K Deficiency ◽  
K Deficiency ◽  
Dependent Protein ◽  
Existing Data

Matrix Gla Protein (MGP), a small Gla vitamin K-dependent protein, is the most powerful natural occurring inhibitor of calcification in the human body. To become biologically active, MGP must undergo vitamin K-dependent carboxylation and phosphorylation. Vitamin K deficiency leads to the inactive uncarboxylated, dephosphorylated form of MGP (dpucMGP). We aimed to review the existing data on the association between circulating dpucMGP and vascular calcification, renal function, mortality, and cardiovascular disease in distinct populations. Moreover, the association between vitamin K supplementation and serum levels of dpucMGP was also reviewed.

scholarly journals Experimental Model of Subclinical Vitamin K Deficiency

Folia Medica ◽  
2020 ◽  
Vol 62 (2) ◽  
pp. 378-384
Author(s):  
Silvia Gancheva ◽  
Martina Kitanova ◽  
Peter Ghenev ◽  
Maria Zhelyazkova-Savova
Keyword(s):  
Vascular Calcification ◽  
Vitamin K ◽  
Coagulation Factors ◽  
Matrix Gla Protein ◽  
Severe Bleeding ◽  
Dosing Schedule ◽  
K Deficiency ◽  
Calcium Deposits ◽  
Subclinical Vitamin ◽  
High Doses

Introduction: 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. Aim: 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. Materials and methods: Two consecutive experiments, each lasting 4 weeks, were required to modify the dosing schedule of warfa­rin 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 mea­sured. Results: The original dosing schedule induced VK deficiency, manifested by arterial calcifications and dramatic changes in carboxyl­ated and uncarboxylated osteocalcin. The modified dosing regimen caused similar vascular calcification and no bleeding. Conclusion: 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.

scholarly journals Causes of Vitamin K Deficiency in Patients on Haemodialysis

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2513
Author(s):  
Signe Wikstrøm ◽  
Katrine Aagaard Lentz ◽  
Ditte Hansen ◽  
Lars Melholt Rasmussen ◽  
Jette Jakobsen ◽  
...  
Keyword(s):  
Vitamin K ◽  
Absorption Capacity ◽  
Protein Supplementation ◽  
Matrix Gla Protein ◽  
Vitamin K1 ◽  
High Concentration ◽  
Vitamin K Deficiency ◽  
Before And After ◽  
K Deficiency ◽  
The Difference

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.

scholarly journals Sevelamer Use in End-Stage Kidney Disease (ESKD) Patients Associates with Poor Vitamin K Status and High Levels of Gut-Derived Uremic Toxins: A Drug–Bug Interaction?

Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 351
Author(s):  
Lu Dai ◽  
Björn K. Meijers ◽  
Bert Bammens ◽  
Henriette de Loor ◽  
Leon J. Schurgers ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Vitamin K ◽  
Phosphate Binder ◽  
Microbial Metabolism ◽  
Uremic Toxins ◽  
Matrix Gla Protein ◽  
Vitamin K Deficiency ◽  
End Stage Kidney Disease ◽  
K Deficiency ◽  
End Stage

Gut microbial metabolism is not only an important source of uremic toxins but may also help to maintain the vitamin K stores of the host. We hypothesized that sevelamer therapy, a commonly used phosphate binder in patients with end-stage kidney disease (ESKD), associates with a disturbed gut microbial metabolism. Important representatives of gut-derived uremic toxins, including indoxyl sulfate (IndS), p-Cresyl sulfate (pCS), trimethylamine N-oxide (TMAO), phenylacetylglutamine (PAG) and non-phosphorylated, uncarboxylated matrix-Gla protein (dp-ucMGP; a marker of vitamin K status), were analyzed in blood samples from 423 patients (65% males, median age 54 years) with ESKD. Demographics and laboratory data were extracted from electronic files. Sevelamer users (n = 172, 41%) were characterized by higher phosphate, IndS, TMAO, PAG and dp-ucMGP levels compared to non-users. Sevelamer was significantly associated with increased IndS, PAG and dp-ucMGP levels, independent of age, sex, calcium-containing phosphate binder, cohort, phosphate, creatinine and dialysis vintage. High dp-ucMGP levels, reflecting vitamin K deficiency, were independently and positively associated with PAG and TMAO levels. Sevelamer therapy associates with an unfavorable gut microbial metabolism pattern. Although the observational design precludes causal inference, present findings implicate a disturbed microbial metabolism and vitamin K deficiency as potential trade-offs of sevelamer therapy.

scholarly journals Vitamin K deficiency in CKD patients: a modifiable risk factor for vascular calcification?

2009 ◽  
Vol 76 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Thilo Krueger ◽  
Ralf Westenfeld ◽  
Markus Ketteler ◽  
Leon J. Schurgers ◽  
Jürgen Floege
Keyword(s):  
Risk Factor ◽  
Vascular Calcification ◽  
Vitamin K ◽  
Modifiable Risk Factor ◽  
Vitamin K Deficiency ◽  
K Deficiency

scholarly journals Kidney Function-Dependence of Vitamin K-Status Parameters: Results from the TransplantLines Biobank and Cohort Studies

Nutrients ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 3069
Author(s):  
Daan Kremer ◽  
Dion Groothof ◽  
Charlotte A. Keyzer ◽  
Coby Eelderink ◽  
Tim J. Knobbe ◽  
...  
Keyword(s):  
Kidney Transplantation ◽  
Cohort Studies ◽  
Kidney Transplant ◽  
Kidney Function ◽  
Vitamin K ◽  
Matrix Gla Protein ◽  
Transplant Recipients ◽  
Kidney Transplant Recipients ◽  
Blood Concentrations ◽  
K Deficiency

High circulating dephosphorylated (dp) uncarboxylated (uc) matrix Gla protein (MGP) and uc osteocalcin (OC) concentrations are regarded as markers of vitamin K-deficiency. However, because MGP and OC are small molecules, they may potentially pass the glomerulus, and their blood concentrations may strongly depend on kidney function. However, many studies with vitamin K-status parameters do not structurally adjust for baseline kidney function, and detailed studies on kidney function-dependence of vitamin K-status markers are lacking. We therefore measured plasma dp-ucMGP using a chemiluminescent assay in 578 kidney transplant recipients (41% females, age 56 ± 13y, 7.5 (3.2 to 13.7)y after transplantation, eGFR 49 ± 17 mL/min/1.73 m2) participating in the prospective TransplantLines Cohort Studies. Additionally, dp-carboxylated MGP, ucOC and carboxylated OC were measured using ELISA in plasma of a subgroup of 60 participants. Finally, dp-ucMGP was measured in a separate cohort of 124 kidney transplant recipients before and three months after kidney transplantation. Dp-ucMGP positively correlated with creatinine, cystatin C, and negatively with eGFR (Spearman’s ρ 0.54, 0.60, and −0.54, respectively, p < 0.001 for all), and each 10 mL/min/1.73 m2 increase in eGFR was associated with a 14.0% lower dp-ucMGP. Additionally, dp-ucMGP strongly declined after kidney transplantation (pretransplantation: 1252 (868 to 1744) pmol/L to posttransplantation: 609 (451 to 914) pmol/L, p < 0.001). Proportions of dp-ucMGP over total MGP and ucOC over total OC were not associated with eGFR. This study highlights that dp-ucMGP is strongly associated with kidney function, and that levels strongly decrease after kidney transplantation. We therefore propose adequate adjustment for kidney function, or the use of kidney function-independent parameters such as proportion of uncarboxylated MGP or OC in the assessment of vitamin K-status in clinical practice and research.

scholarly journals Current Therapy in CKD Patients Can Affect Vitamin K Status

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1609 ◽  
Author(s):  
Mario Cozzolino ◽  
Giuseppe Cianciolo ◽  
Manuel Alfredo Podestà ◽  
Paola Ciceri ◽  
Andrea Galassi ◽  
...  
Keyword(s):  
Vascular Calcification ◽  
Vitamin K ◽  
Bone Mineralization ◽  
Current Therapy ◽  
Phosphate Binders ◽  
Mineral Density ◽  
Vitamin K Deficiency ◽  
Mineral And Bone Disorder ◽  
Related Risk ◽  
K Deficiency

Chronic kidney disease (CKD) patients have a higher risk of cardiovascular (CVD) morbidity and mortality compared to the general population. The links between CKD and CVD are not fully elucidated but encompass both traditional and uremic-related risk factors. The term CKD-mineral and bone disorder (CKD-MBD) indicates a systemic disorder characterized by abnormal levels of calcium, phosphate, PTH and FGF-23, along with vitamin D deficiency, decreased bone mineral density or altered bone turnover and vascular calcification. A growing body of evidence shows that CKD patients can be affected by subclinical vitamin K deficiency; this has led to identifying such a condition as a potential therapeutic target given the specific role of Vitamin K in metabolism of several proteins involved in bone and vascular health. In other words, we can hypothesize that vitamin K deficiency is the common pathogenetic link between impaired bone mineralization and vascular calcification. However, some of the most common approaches to CKD, such as (1) low vitamin K intake due to nutritional restrictions, (2) warfarin treatment, (3) VDRA and calcimimetics, and (4) phosphate binders, may instead have the opposite effects on vitamin K metabolism and storage in CKD patients.

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