Antenatal steroid as an independent risk factor for vitamin K2 deficiency in newborns: A Chinese single-center, retrospective study.

OBJECTIVES: To identified vitamin K2 deficiency rate and risk factors among newborns in China and assess the importance of high-risk maternal intakes of vitamin K2. METHODS: This retrospective study was performed at the Neonatology Department, the Affiliated Hospital of Guangdong Medical University, China. Routinely collected mother-neonate hospitalization data from July 2020 to January 2021 were analyzed. In total, data from 200 neonates who had completed vitamin K2 tests were utilized to assess the prevalence of vitamin K2 deficiency and identify the potential risk factors. According to the vitamin K2 level, the neonates were divided into 2 groups: cases (vitamin K2 deficiency) and controls (no vitamin K2 deficiency). The potential risk factors for vitamin K2 deficiency were evaluated by univariate and multivariate logistic regression. RESULTS: The vitamin K2 level in 24 of the 200 neonates was undetectable (<0.05 ng/mL). The prevalence of low serum vitamin K2 (<0.1 ng/ml) was 33%. Study subjects with antenatal corticosteroids use had an approximately 5-fold greater risk of developing vitamin K2 deficiency. In the univariate analyses, small-for-gestational-age (SGA), caesarean section, maternal gestational diabetes and premature rupture of the membranes were risk factors for vitamin K2 deficiency. In the multivariate logistic regression analysis, high antenatal corticosteroids use, cesarean section, and SGA were independently associated with vitamin K2 deficiency. CONCLUSION: The present study demonstrated that antenatal corticosteroids use is independently associated with vitamin K2 deficiency. This finding highlights the importance of routine vitamin K2 supplementation in late-stage pregnant women and neonates in China.

Exclusively breastmilk-fed preterm infants are at high risk of developing subclinical vitamin K deficiency despite intramuscular prophylaxis at birth.

BACKGROUND: There is near-global consensus that all newborns be given parenteral vitamin K1 (VK1 ) at birth as prophylaxis against VK deficiency bleeding (VKDB). Breastmilk has a low VK content and cases of late VKDB are reported in exclusively breastmilk-fed preterm infants despite VK prophylaxis at birth. OBJECTIVES: To assess the prevalence of functional VK insufficiency in preterm infants based on elevated under-γ-carboxylated (Glu) species of Gla proteins, factor II (PIVKA-II), and osteocalcin (GluOC), synthesized by liver and bone, respectively. PATIENTS/METHODS: Prospective, multicenter, observational study in preterm infants born <33 weeks' gestation. Blood samples and dietary history were collected before hospital discharge, and after discharge at 2-3 months' corrected age. Outcome measures were serum VK1 , PIVKA-II, and %GluOC (GluOC as a percentage of the sum of GluOC plus GlaOC) compared between exclusively breastmilk-fed and formula/mixed-fed infants after discharge. RESULTS: After discharge, breastmilk-fed babies had significantly lower serum VK1 (0.15 vs. 1.81 µg/L), higher PIVKA-II (0.10 vs. 0.02 AU/ml) and higher %GluOC (63.6% vs. 8.1%) than those receiving a formula/mixed-feed diet. Pre-discharge (based on elevated PIVKA-II), only one (2%) of 45 breastmilk-fed infants was VK insufficient. After discharge, eight (67%) of 12 exclusively breastmilk-fed babies were VK insufficient versus only one (4%) of 25 formula/mixed-fed babies. CONCLUSIONS: Preterm infants who remain exclusively or predominantly human breastmilk-fed after neonatal unit discharge are at high risk of developing subclinical VK deficiency in early infancy. Routine postdischarge VK1 supplementation of breastfed infants to provide intakes comparable to those from formula milks should prevent this deficiency.

Vitamin K Supplementation in Chronic Kidney Disease Patients: Where is the Evidence?

Vascular calcification (VC) is highly prevalent in Chronic Kidney Disease (CKD) patients, progresses gradually with deterioration of kidney function and is a strong, independent predictor of cardiovascular (CV) mortality. Matrix Gla Protein (MGP), the most potent inhibitor of VC, requires vitamin K as a co-factor to become biologically active. Accumulating epidemiological data have associated vitamin K depletion with VC progression and CV outcomes. CKD patients are characterized by poor vitamin K status and at the same time, pronounced CV calcification. In early and advanced CKD, including end-stage kidney disease, exogenous supplementation of vitamin K (especially with menaquinone 7, its most bioavailable form) might decrease the inactive form of MGP (dephosphorylated, uncarboxylated MGP) and probably retard the progression or even reverse VC. Here, we focus and discuss the interventional human studies of vitamin K supplementation in CKD patients and suggest future directions in this area of interest.

Vitamin K and cardiovascular complications in chronic kidney disease patients.

Vitamin K, well known for its role in coagulation, encompasses 2 major subgroups: vitamin K1 is exclusively synthesized by plants, whereas vitamin K2 mostly originates from bacterial synthesis. Vitamin K serves as a cofactor for the enzyme γ-glutamyl carboxylase, which carboxylates and thereby activates various vitamin K-dependent proteins. Several vitamin K-dependent proteins are synthesized in bone, but the role of vitamin K for bone health in chronic kidney disease patients, in particular the prevention of osteoporosis, is still not firmly established. Herein, we focus on another prominent action of vitamin K, in particular vitamin K2 (namely, the activation of matrix γ-carboxyglutamic acid protein, the most potent inhibitor of cardiovascular calcifications). Multiple observational studies link relative vitamin K deficiency or low intake to cardiovascular calcification progress, morbidity, and mortality. Patients with advanced chronic kidney disease are particularly vitamin K deficient, in part because of dietary restrictions but possibly also due to impaired endogenous recycling of vitamin K. At the same time, this population is characterized by markedly accelerated cardiovascular calcifications and mortality. High-dose dietary supplementation with vitamin K2, in particular the most potent form, menaquinone 7, can potently reduce circulating levels of dephosphorylated uncarboxylated (i.e., inactive matrix γ-carboxyglutamic acid protein) in patients with end-stage kidney disease. However, despite this compelling data basis, several randomized controlled trials with high-dose menaquinone 7 supplements in patients with advanced chronic kidney disease have failed to confirm cardiovascular benefits. Herein, we discuss potential reasons and solutions for this.

Vitamin K and vascular calcification.

PURPOSE OF REVIEW: Vascular calcification is a common and important cardiovascular risk factor in patients with chronic kidney disease (CKD). Recent advances in the understanding of the biology of vascular calcification implicate vitamin K-dependent proteins as important regulators in this process. This review highlights recent key advances in vascular biology, epidemiology, and clinical trials in this rapidly evolving field. RECENT FINDINGS: Vitamin K deficiency is associated with increasing severity of vascular calcification among patients with CKD, but the relationship with cardiovascular disease and mortality is inconsistent. Vitamin K may reduce calcification propensity by improving the activity of vitamin K-dependent calcification inhibitors or by down-regulating components of the innate immune system to reduce inflammation. However, recent randomized controlled trials in patients with diabetes, CKD, renal transplant, and on hemodialysis have failed to demonstrate improvement in vascular calcification or stiffness after vitamin K treatment. SUMMARY: Current evidence does not support a clinically useful role for vitamin K supplementation to prevent or reverse vascular calcification in patients with CKD. Knowledge gaps remain, particularly whether higher doses of vitamin K, longer duration of supplementations, or use a vitamin K as a part of a package of measures to counteract vascular calcification might be effective.

Vitamins K and D deficiency in severe motor and intellectually disabled patients.

OBJECTIVES: We aimed to determine serum 25-hydroxyvitamin D (25(OH)D) and undercarboxylated osteocalcin (ucOC) levels in severe motor and intellectual disabilities (SMID) patients and their association with bone turnover biomarkers. METHODS: We assessed vitamin D and K levels as indicators of osteoporosis in institutionalized adults with SMID. From December 2019 to February 2020, 93 institutionalized patients (48 men, 45 women; median age, 49 years) underwent annual routine examinations. Serum ucOC, 25(OH)D, bone-specific alkaline phosphatase (BAP), and tartrate-resistant acid phosphatase A 5b (TRACP-5b) levels as bone formation and resorption markers and calcium and phosphorous levels were measured. Vitamin K deficiency was indirectly assessed based on ucOC levels. RESULTS: Mean ucOC levels were higher than normal (i.e., vitamin K deficiency). Serum 25(OH)D levels were markedly diminished. Overall, 86% of patients had deficient 25(OH)D levels. These 25(OH)D-deficient patients had higher ucOC levels. Multiple linear regression analysis revealed an inverse correlation between 25(OH)D and ucOC levels. ucOC levels were significantly higher and 25(OH)D levels were significantly lower in tube feeding. TRACP-5b levels were significantly higher in elderly than in young women. BAP and TRACP-5b levels were normal in adults. No relationship existed between vitamin D and antiepileptic drug use. CONCLUSIONS: Vitamin K and D co-deficiency was common in SMID patients. Vitamin K and D deficiencies were worse in tube-fed patients than in oral intake patients. SMID patients should undergo regular monitoring of vitamin D and K levels and supplementation of these vitamins.

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

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.

Prevalence of vitamin K deficiency in older people with hip fracture.

Introduction: Vitamin K plays an important role in blood coagulation. Diet is the main source of vitamin K and body stores are depleted in days, hence deficiency is common in malnourished older people. A high proportion of people who sustain a hip fracture are already malnourished, compounded by fasting for surgery which might further increase deficiency. We wanted to explore the prevalence of vitamin K deficiency in hip fracture patients and the impact of a short period of fasting.Methods: In consecutive patients hospitalised with a hip fracture, we measured vitamin K and PIVKA-II (undercarboxylated factor II - a marker of subclinical vitamin K status) on admission and on first post-operative day. We excluded those on anticoagulants.Results: N = 62 participated; 4 had missing pre-op vitamin K samples and n = 3 had no surgery leaving n = 55 with paired samples. Mean age was 80.0 ± 9.6 years, 33% males. Prevalence of subclinical vitamin K deficiency on admission was 36% (20/55) based on reference range of > 0.15µg/L. The proportion with subclinical K deficiency after surgery rose to 64% (35/55), p < 0.05. 13% had detectable PIVKA-II concentrations pre-operatively, 15% did post-operatively. None had abnormal prothrombin time. Vitamin K status was not associated with post-operative haemoglobin drop or transfusion requirements.Conclusion: Prevalence of vitamin K deficiency in hip fracture patients is high and increases further following a short period of fasting. Though no significant impact was noted on peri-operative blood loss, larger studies are warranted to explore this, and the potential role of vitamin K supplements peri-operatively.

Multiple vitamin deficiencies additively increase the risk of incident fractures in Japanese postmenopausal women.

The associations of multiple vitamin deficiencies on incident fractures were uncertain, the relationships between serum vitamin markers and incident bone fractures were investigated in Japanese postmenopausal women. The number of deficiencies was additively associated with incident fracture after adjustment for possible confounding factors including the treatment of osteoporosis. INTRODUCTION: To evaluate the associations of multiple vitamin deficiencies on incident fractures, the relationships between serum vitamin markers and incident bone fractures were investigated in Japanese postmenopausal women. METHODS: This analysis used a subset of the ongoing cohort maintained by a primary care institution. Inclusion criteria of the present study were postmenopausal women aged ≥ 50 years, without vitamin supplementation and secondary osteoporosis. Baseline serum concentrations of 25-hydroxyvitamin D (25(OH)D), undercarboxylated osteocalcin (ucOC), and homocysteine (Hcy) were measured to assess vitamin D, vitamin K, and vitamin B, respectively. Since 25(OH) D positively relates to vitamin D, ucOC and Hcy negatively relate to vitamin K and vitamin B nutrients, respectively, the subjects with lower (25(OH)D) or higher (ucOC or Hcy) values than each median value was defined as subjects with the corresponding vitamin deficiency. Subjects were divided into four groups according to the number of deficiency: no deficiency, single deficiency, double deficiencies, and triple deficiencies. Relationships between the vitamin deficiencies and incident fractures were evaluated by Cox regression analysis. RESULTS: A total of 889 subjects were included in this analysis; their mean and SD age was 68.3 ± 9.5 years, and the follow-up period was 6.3 ± 5.1 years. The numbers of subjects in the four groups were 139 (15.6%), 304 (34.2%), 316 (35.5%), and 130 (14.6%) for the groups with no, single, double, and triple deficiencies, respectively. Incident fractures were observed in 264 subjects (29.7%) during the observation period. The number of deficiencies was significantly associated with incident fracture (hazard ratio 1.25, 95% confidence interval 1.04-1.50, P = 0.018) after adjustment for possible confounding factors including the treatment of osteoporosis. CONCLUSION: Accumulation of vitamin deficiencies was related to incident fractures.

Prevalencia de deficiencia de vitamina K y factores asociados en pacientes con fibrosis quística sin aporte suplementario / Prevalence of vitamin K deficiency and associated factors in non-supplemented cystic fibrosis patients

Introducción. La deficiencia de vitamina K es prevalente en pacientes con fibrosis quística (FQ) aun con aporte suplementario. Se desconocen factores de riesgo fiables para determinar su ocurrencia. Nuestro objetivo fue evaluar la prevalencia de deficiencia de vitamina K y factores asociados en los pacientes con FQ que no recibían aporte suplementario. Métodos. Se determinaron protrombina inducida por ausencia de vitamina K (PIVKA-II) y osteocalcina infracarboxilada (OCic). Se evaluó el estado clínico y su relación con la deficiencia de vitamina K. El análisis estadístico incluyó prueba de Mann-Whitney, ANOVA o Kruskal-Wallis, prueba χ² o prueba de Fisher-Freeman-Halton y regresión logística múltiple lineal y escalonada hacia adelante. Resultados. Se incluyeron 79 pacientes con FQ de entre 0,4-25,3 años. Se observaron valores anómalos de PIVKA-II y OCic en 56 (70,9%) y 45 (57,0%) pacientes. Los pacientes con PIVKA-II elevada eran significativamente mayores (p = 0,0184) y tenían puntajes Z de peso corporal (p= 0,0297) inferiores a los pacientes que tenían concentraciones normales. No se hallaron diferencias entre los pacientes con OCic normal o patológica. Se notificaron valores anómalos de PIVKA-II y OCic más frecuentemente en pacientes con dos mutaciones graves en el gen CFTR y con un estado nutricional malo/deficiente. Los análisis de regresión múltiple lineal y de regresión múltiple escalonada hacia adelante no revelaron factores predictivos sólidos para determinar la deficiencia de vitamina K. Conclusión. La deficiencia de vitamina K es altamente prevalente durante la evolución natural de la fibrosis quística. No se hallaron determinantes clínicos fiables para precisar su ocurrencia.

Introduction. Vitamin K deficiency is highly prevalent in cystic fibrosis (CF) patients despite supplementation. Moreover, no reliable risk factors for its occurrence are known. The aim was to assess the prevalence of vitamin K deficiency and associated factors in non-supplemented CF patients. Methods. Prothrombin concentration induced by vitamin K absence (PIVKA-II) and the undercarboxylated osteocalcin percentage (u-OC) were determined. In all patients clinical status was assessed and its relation to vitamin K deficiency determined. The following tests were used for statistical analysis: Mann-Whitney test, ANOVA test or the Kruskal Wallis test, the chi-squared test or the Fisher-Freeman-Halton test, and multiple linear and multiple forward stepwise logistic regression analysis. Results. The study group comprised 79 CF patients aged 0.4-25.3 years. PIVKA-II and u-OC were abnormal in 56 (70.9%) and 45 (57.0%) patients. Patients with elevated PIVKA-II were significantly older (p= 0.0184) and had lower Z-score values for body weight (p= 0.0297) than those with normal concentrations. Patients with normal or pathological u-OC percentage did not differ. Abnormal PIVKA-II and u-OC were reported more frequently in subjects with two severe CFTR mutations and with worse/poor nutritional status. Multiple linear and forward stepwise regression analyses did not reveal strong predictive factors of vitamin K deficiency. Conclusion. Vitamin K deficiency is highly prevalent in the natural course of cystic fibrosis. There are no reliable clinical determinants of its occurrence.

Prevalence of vitamin K deficiency and associated factors in non-supplemented cystic fibrosis patients. / Prevalencia de deficiencia de vitamina K y factores asociados en pacientes con fibrosis quística sin aporte suplementario.

INTRODUCTION: Vitamin K deficiency is highly prevalent in cystic fibrosis (CF) patients despite supplementation. Moreover, no reliable risk factors for its occurrence are known. The aim was to assess the prevalence of vitamin K deficiency and associated factors in non-supplemented CF patients. METHODS: Prothrombin concentration induced by vitamin K absence (PIVKA-II) and the undercarboxylated osteocalcin percentage (u-OC) were determined. In all patients clinical status was assessed and its relation to vitamin K deficiency determined. The following tests were used for statistical analysis: Mann-Whitney test, ANOVA test or the Kruskal Wallis test, the chi-squared test or the Fisher-Freeman-Halton test, and multiple linear and multiple forward stepwise logistic regression analysis. RESULTS: The study group comprised 79 CF patients aged 0.4-25.3 years. PIVKA-II and u-OC were abnormal in 56 (70.9%) and 45 (57.0%) patients. Patients with elevated PIVKA-II were significantly older (p= 0.0184) and had lower Z-score values for body weight (p= 0.0297) than those with normal concentrations. Patients with normal or pathological u-OC percentage did not differ. Abnormal PIVKA-II and u-OC were reported more frequently in subjects with two severe CFTR mutations and with worse/poor nutritional status. Multiple linear and forward stepwise regression analyses did not reveal strong predictive factors of vitamin K deficiency. CONCLUSION: Vitamin K deficiency is highly prevalent in the natural course of cystic fibrosis. There are no reliable clinical determinants of its occurrence.

INTRODUCCIÓN: La deficiencia de vitamina K es prevalente en pacientes con fibrosis quística (FQ) aun con aporte suplementario. Se desconocen factores de riesgo fiables para determinar su ocurrencia. Nuestro objetivo fue evaluar la prevalencia de deficiencia de vitamina K y factores asociados en los pacientes con FQ que no recibían aporte suplementario. MÉTODOS: Se determinaron protrombina inducida por ausencia de vitamina K (PIVKA-II) y osteocalcina infracarboxilada (OCic). Se evaluó el estado clínico y su relación con la deficiencia de vitamina K. El análisis estadístico incluyó prueba de Mann-Whitney, ANOVA o Kruskal-Wallis, prueba χ2 o prueba de Fisher-Freeman-Halton y regresión logística múltiple lineal y escalonada hacia adelante. RESULTADOS: Se incluyeron 79 pacientes con FQ de entre 0,4-25,3 años. Se observaron valores anómalos de PIVKA-II y OCic en 56 (70,9%) y 45 (57,0%) pacientes. Los pacientes con PIVKA-II elevada eran significativamente mayores (p = 0,0184) y tenían puntajes Z de peso corporal (p= 0,0297) inferiores a los pacientes que tenían concentraciones normales. No se hallaron diferencias entre los pacientes con OCic normal o patológica. Se notificaron valores anómalos de PIVKA-II y OCic más frecuentemente en pacientes con dos mutaciones graves en el gen CFTR y con un estado nutricional malo/deficiente. Los análisis de regresión múltiple lineal y de regresión múltiple escalonada hacia adelante no revelaron factores predictivos sólidos para determinar la deficiencia de vitamina K. CONCLUSIÓN: La deficiencia de vitamina K es altamente prevalente durante la evolución natural de la fibrosis quística. No se hallaron determinantes clínicos fiables para precisar su ocurrencia.

Coagulopathy in Zellweger spectrum disorders: a role for vitamin K.

INTRODUCTION: Zellweger spectrum disorders (ZSDs) are caused by an impairment of peroxisome biogenesis, resulting in multiple metabolic abnormalities. This leads to a range of symptoms, including hepatic dysfunction and coagulopathy. This study evaluated the incidence and severity of coagulopathy and the effect of vitamin K supplementation orally and IV in ZSD. METHODS: Data were retrospectively retrieved from the medical records of 30 ZSD patients to study coagulopathy and the effect of vitamin K orally on proteins induced by vitamin K absence (PIVKA-II) levels. Five patients from the cohort with a prolonged prothrombin time, low factor VII, and elevated PIVKA-II levels received 10 mg of vitamin K IV. Laboratory results, including thrombin generation, at baseline and 72 h after vitamin K administration were examined. RESULTS: In the retrospective cohort, four patients (13.3%) experienced intracranial bleedings and 14 (46.7%) reported minor bleeding. No thrombotic events occurred. PIVKA-II levels decreased 38% after start of vitamin K therapy orally. In the five patients with a coagulopathy, despite treatment with oral administration of vitamin K, vitamin K IV caused an additional decrease (23%) of PIVKA-II levels and increased thrombin generation. CONCLUSION: Bleeding complications frequently occur in ZSD patients due to liver disease and vitamin K deficiency. Vitamin K deficiency is partly corrected by vitamin K supplementation orally, and vitamin K administered IV additionally improves vitamin K status, as shown by further decrease of PIVKA-II and improved thrombin generation.

Vitamin K deficiency: the linking pin between COPD and cardiovascular diseases?

Cardiovascular diseases are prevalent in patients with chronic obstructive pulmonary disease (COPD). Their coexistence implies that many COPD patients require anticoagulation therapy. Although more and more replaced by direct oral anticoagulants, vitamin K antagonists (VKAs) are still widely used. VKAs induce profound deficiency of vitamin K, a key activator in the coagulation pathway. It is recognized however that vitamin K is also an essential cofactor in the activation of other extrahepatic proteins, such as matrix Gla protein (MGP), a potent inhibitor of arterial calcification. No or insufficient MGP activation by the use of VKAs is associated with a rapid progression of vascular calcification, which may enhance the risk for overt cardiovascular disease. Vitamin K consumption, on the other hand, seems to have a protective effect on the mineralization of arteries. Furthermore, vascular calcification mutually relates to elastin degradation, which is accelerated in patients with COPD associating with impaired survival. In this commentary, we hypothesize that vitamin K is a critical determinant to the rate of elastin degradation. We speculate on the potential link between poor vitamin K status and crucial mechanisms of COPD pathogenesis and raise concerns about the use of VKAs in patients with this disease. Future intervention studies are needed to explore if vitamin K supplementation is able to reduce elastin degradation and vascular calcification in COPD patients.

Vitamin K2 supplementation and arterial stiffness among renal transplant recipients-a single-arm, single-center clinical trial.

Subclinical vitamin K deficiency is prevalent among renal transplant recipients and is associated with an increased risk of cardiovascular disease. However, the association between vitamin K supplementation and improvement of arterial stiffness has not been explored in the renal transplant population. The KING trial (vitamin K2 In reNal Graft) is a single-arm study that evaluated the association between the change in vitamin K status and indices of arterial stiffness following 8 weeks of menaquinone-7 (vitamin K2) supplementation (360 µg once daily) among renal transplant recipients (n = 60). Arterial stiffness was measured using carotid-femoral pulse wave velocity (cfPWV). Subclinical vitamin K deficiency was defined as plasma concentration of dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP) >500 pmol/L.At baseline, 53.3% of the study subjects had subclinical vitamin K deficiency. Supplementation was associated with a 14.2% reduction in mean cfPWV at 8 weeks (cfPWV pre-vitamin K2 = 9.8 ± 2.2 m/s vs. cfPWV post-vitamin K2 = 8.4 ± 1.5 m/s; P < .001). Mean dp-ucMGP concentrations were also significantly reduced by 55.1% following menaquinone-7 supplementation with a reduction in the prevalence of subclinical deficiency by 40% (P = .001). When controlled for age, durations of hemodialysis and transplantation, and the change in 24-hour mean arterial pressure, the improvement in arterial stiffness was independently associated with the reduction in dp-ucMGP concentration (P = .014).Among renal transplant recipients with stable graft function, vitamin K2 supplementation was associated with improvement in subclinical vitamin K deficiency and arterial stiffness. (Clinicaltrials.gov: NCT02517580).

Prevention of vasculopathy by vitamin K supplementation: can we turn fiction into fact?

With the discovery that vitamin K-dependent matrix Gla-protein (MGP) is a strong and modifiable factor in the prevention of arterial calcification, vitamin K was put forward as novel treatment option in cardiovascular disease. The vasculoprotective properties of vitamin K are in part based on the ability to improve gamma-glutamylcarboxylation of MGP, which is a prerequisite for MGP as a calcification inhibitor. Data from experimental animal models reveal that high intake of vitamin K can prevent and even reverse vascular calcifications. In addition, clinical data demonstrate that prescription of vitamin K antagonists for long-term oral anticoagulant therapy accelerates vascular calcification. However, controlled data from randomized prospective vitamin K interventional trials are lacking, thereby weakening a general recommendation for supplementation. The present article summarizes our current knowledge on the association between vitamin K and cardiovascular health. Additionally, we focus on an outlook on important ongoing prospective vitamin K intervention studies. These studies address the issues whether vitamin K substitution helps modifying relevant cardiovascular surrogates such as vascular calcification and whether non-vitamin K oral anticoagulants provide an alternative to support cardiovascular health benefits. So research about cardiovascular protection by vitamin K is an evolving field in which we expect a boost of novel and relevant evidence shortly.

Vitamin K and other markers of micronutrient status in morbidly obese patients before bariatric surgery.

BACKGROUND: Micronutrient deficiencies occur in morbidly obese patients. The aim of this study was to assess vitamin deficiencies prior to bariatric surgery including vitamin K about which there is little data in this population. METHODS: A prospective assessment of 118 consecutive patients was performed. Clinical allied with haematological and biochemical variables were measured. Micronutrients measured included vitamins K1 , PIVKA-II (protein-induced in vitamin K absence factor II), vitamin D, vitamin B12 (holotranscobalamin), iron, transferrin and folate. RESULTS: Patients were aged 49 ± 11 [mean (SD, standard deviation)] years, body mass index (BMI) 50 ± 8 kg/m(2), 66% female and 78% Caucasian. Hypertension was present in 47% and type 2 diabetes in 32%. Vitamin D supplements had been prescribed in 8%. Micronutrient insufficiencies were found for vitamin K (40%), vitamin D (92%) and vitamin B12 (25%), and also iron (44%) and folate (18%). Normocalcaemic vitamin D insufficiency with secondary hyperparathyroidism was present in 18%. Iron and transferrin levels were associated with age, sex and estimated glomerular filtration rate. Vitamin K levels were associated with age, and inversely with BMI and diabetes mellitus; and PIVKA-II with smoking, triglycerides and liver function markers. Vitamin D levels were associated with statin use and prescription of supplements and inversely with BMI. Vitamin B12 levels were associated with ethnicity and HbA1c. CONCLUSION: Micronutrient status shows differing relationships with age, gender and BMI. Vitamin K insufficiency was present in 40% and not related to deficiencies in other vitamins or micronutrients. Vitamin D and vitamin K supplementation should be considered prebariatric surgery in patients with diabetes or severe insulin resistance.

Rise in late onset vitamin K deficiency bleeding in young infants because of omission or refusal of prophylaxis at birth.

BACKGROUND: Newborns are at risk for vitamin K deficiency and subsequent bleeding unless supplemented at birth. Vitamin K deficiency bleeding is an acquired coagulopathy in newborn infants because of accumulation of inactive vitamin K-dependent coagulation factors, which leads to an increased bleeding tendency. Supplementation of vitamin K at birth has been recommended in the United States since 1961 and successfully reduced the risk of major bleeding. Refusal or omission of vitamin K prophylaxis is increasing and puts newborn infants at risk for life-threatening bleeding. PATIENTS: Over an eight month period, we encountered seven infants with confirmed vitamin K deficiency; five of these patients developed vitamin K deficiency bleeding. RESULTS: The mean age of the seven infants with vitamin K deficiency was 10.3 weeks (range, 7-20 weeks); manifestations ranged from overt bleeding to vomiting, poor feeding, and lethargy. None of the infants had received vitamin K at birth, and all were found to have profound derangement of coagulation parameters, which corrected rapidly with administration of vitamin K in IV or intramuscular form. Four of the seven infants had intracranial hemorrhage; two of these infants required urgent neurosurgical intervention. CONCLUSION: Supplementation of vitamin K at birth for all newborns prevents major hemorrhagic complications, such as intracranial bleeding, due to vitamin K deficiency. Parental refusal of vitamin K is increasingly common. It is critical that health care providers and the public be made aware of the varied presentation of this preventable acquired coagulopathy.

Effect of vitamin K2 supplementation on functional vitamin K deficiency in hemodialysis patients: a randomized trial.

BACKGROUND: Vascular calcification is a predictor of cardiovascular morbidity and mortality. Hemodialysis patients experience severe vascular calcifications. Matrix Gla protein (MGP) is a central calcification inhibitor of the arterial wall; its activity depends on vitamin K-dependent γ-glutamate carboxylation. Uncarboxylated MGP, formed as a result of vitamin K deficiency, is associated with cardiovascular disease. Recent studies suggest poor vitamin K status in hemodialysis patients. We therefore aimed to investigate whether daily vitamin K supplementation improves the bioactivity of vitamin K-dependent proteins in hemodialysis patients, assessed by circulating dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and uncarboxylated prothrombin (PIVKA-II [protein induced by vitamin K absence II]). STUDY DESIGN: Interventional randomized non-placebo-controlled trial with 3 parallel groups. SETTING & PARTICIPANTS: 53 long-term hemodialysis patients in stable conditions, 18 years or older. 50 healthy age-matched individuals served as controls. INTERVENTIONS: Menaquinone-7 (vitamin K(2)) treatment at 45, 135, or 360 µg/d for 6 weeks. OUTCOMES: Plasma levels of dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and PIVKA-II. MEASUREMENTS: Plasma levels were assessed using enzyme-linked immunosorbent assays. RESULTS: At baseline, hemodialysis patients had 4.5-fold higher dephosphorylated-uncarboxylated MGP and 8.4-fold higher uncarboxylated osteocalcin levels compared with controls. PIVKA-II levels were elevated in 49 hemodialysis patients. Vitamin K(2) supplementation induced a dose- and time-dependent decrease in circulating dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and PIVKA-II levels. Response rates in the reduction in dephosphorylated-uncarboxylated MGP levels were 77% and 93% in the groups receiving 135 µg and 360 µg of menaquinone-7, respectively. LIMITATIONS: Small sample size. CONCLUSIONS: This study confirms that most hemodialysis patients have a functional vitamin K deficiency. More importantly, it is the first study showing that inactive MGP levels can be decreased markedly by daily vitamin K(2) supplementation. Our study provides the rationale for intervention trials aimed at decreasing vascular calcification in hemodialysis patients by vitamin K supplementation.

Hydrolysed formula is a risk factor for vitamin K deficiency in infants with unrecognised cholestasis.

OBJECTIVES: Vitamin K deficiency (VKD) may cause life-threatening haemorrhages, especially in breast-fed infants with unrecognised cholestasis. Interestingly, hypoallergenic formulas appear overrepresented in reported cases of VKD bleeding (VKDB) in formula-fed infants. We therefore assessed whether the risk of VKD in formula-fed infants with cholestasis is associated with hypoallergenic formulas. PATIENTS AND METHODS: Infants born in the Netherlands between January 1991 and December 2006 with cholestatic jaundice due to biliary atresia (BA) or to α-1-antitrypsin deficiency (A1ATD) were identified in the Netherlands Study Group for Biliary Atresia Registry and the A1ATD registry, respectively. The relative risk (RR) of VKDB in patients with BA or A1ATD was calculated for different formula types. The influence of prior or ongoing breast-feeding on the RR of VKDB was also assessed. RESULTS: A total of 179 infants with either BA (139) or A1ATD (40) were included. One hundred eighteen infants were formula fed; 8 presented with VKD. Six of these 8 infants (75%) received hypoallergenic formula (whey-based hydrolysate in 4). One infant on whey-based hydrolysed formula presented with VKDB. Risk factor analysis revealed that infants receiving hydrolysed, especially whey-based, formula, had a strongly increased risk of VKD (RR 25.0 [6.4-97.2], P < 0.001)) compared with infants receiving regular formula. Prior or ongoing breast-feeding was not significantly associated with VKD. CONCLUSIONS: Infants with cholestasis receiving (whey-based) hydrolysed formula are at increased risk of developing VKD, compared with infants receiving regular formula. Because VKD may lead to serious haemorrhages, infants receiving whey-based hydrolysed formulas may need additional vitamin K supplementation.

Postoperative metabolic and nutritional complications of bariatric surgery.

Bariatric surgery has become an increasingly important method for management of medically complicated obesity. In patients who have undergone bariatric surgery, up to 87% with type 2 diabetes mellitus develop improvement or resolution of their disease postoperatively. Bariatric surgery can reduce the number of absorbed calories through performance of either a restrictive or a malabsorptive procedure. Patients who have undergone bariatric surgery require indefinite, regular follow-up care by physicians who need to follow laboratory parameters of macronutrient as well as micronutrient malnutrition. Physicians who care for patients after bariatric surgery need to be familiar with common postoperative syndromes that result from specific nutrient deficiencies.