Vitamin K and bone health

Effects of sodium dehydroacetate on broiler chicken bones

Sodium dehydroacetate (DHA-Na) is a fungicidal preservative widely used in food and animal feed. DHA-Na can induce coagulation disorders in rats and poultry by inhibiting carboxylation of vitamin K-dependent proteins; it can also impair bone development in zebrafish. However, the effects of DHA-Na on broiler chicken bones remain unknown. Here, we assessed whether DHA-Na impairs bone development in broiler chickens. We administered Suji yellow chickens with 200 to 800 mg/kg DHA-Na, 2 mg/kg vitamin K, or both for 2 mo. Bone metabolite-related serum indicators, tissue micromorphology, and relevant protein expression were monitored during the treatment period. We also assessed primary chicken osteoblast activity, differentiation, and bone metabolite-related proteins after treatment with DHA-Na, vitamin K, or both. The results demonstrated that DHA-Na reduced bone index values and serum and bone osteoblast differentiation marker levels but blocked bone vitamin K cycle. DHA-Na also increased serum osteoclast differentiation marker levels, as well as the bone ratio of receptor activator of nuclear factor kappa-Β ligand to osteoprotegerin ratio. Moreover, DHA-Na reduced bone trabecular number, thickness, and area and increased trabecular separation considerably. In general, compared with the control group, the DHA-Na group demonstrated impairments in osteoblast activity and differentiation, as well as in the vitamin K cycle. By contrast, vitamin K supplementation led to considerable attenuation of the DHA-Na-induced decrease in osteogenic marker levels, along with a considerable increase in serum bone absorption marker levels and restoration of DHA-Na-induced bone microstructure damage. Vitamin K also attenuated DHA-Na-induced impairment in osteoclasts. In conclusion, the results indicated that in broiler chickens, DHA-Na supplementation can damage bones by inhibiting osteoblast function and increasing osteoclast activity; this damage can be prevented through vitamin K supplementation.

The relationship between height and fruit/vegetable intakes in adults: A nationwide cross-sectional study

Background: Worldwide, fruit and vegetable intake is below recommendations. There is increasing evidence to suggest an association between height and diet. Aim: to analyse the associations of fruit and vegetable intake with attained height in Portuguese adults. Methods: A representative sample of 17 480 Portuguese adults (56.7% women) participated in this cross-sectional study. The survey comprised sociodemographic characteristics and self-reported height and weight. We performed regression models to assess the associations between height and fruit and vegetable consumption. Results: Compared with no intakes, those men with higher fruit and vegetables intake had 0.54 cm (95% CI 0.04; 1.04) greater height. Also, women with higher intakes of vegetables, fruit and vegetables combined were directly associated with a greater height of 0.29 cm (95% CI 0.03; 0.56 in vegetables) and 0.51 cm (95% CI 0.09; 0.93 in fruit and vegetables combined). Conclusion: Greater consumption of fruit and vegetables was directly associated with higher height in adults. From a health promotion perspective, intervention programmes aiming at improving fruit and vegetable intake should be highlighted so that full height potential is achieved.

Association of Air Pollution with a Urinary Biomarker of Biological Aging and Effect Modification by Vitamin K in the FLEMENGHO Prospective Population Study

BACKGROUND

A recently developed urinary peptidomics biological aging clock can be used to study accelerated human aging. From 1990 to 2019, exposure to airborne particulate matter (PM) became the leading environmental risk factor worldwide.

OBJECTIVES

This study investigated whether air pollution exposure is associated with accelerated urinary peptidomic aging, independent of calendar age, and whether this association is modified by other risk factors.

METHODS

In a Flemish population, the urinary peptidomic profile (UPP) age (UPP-age) was derived from the urinary peptidomic profile measured by capillary electrophoresis coupled with mass spectrometry. UPP-age-R was calculated as the residual of the regression of UPP-age on chronological age, which reflects accelerated aging predicted by UPP-age, independent of chronological age. A high-resolution spatial-temporal interpolation method was used to assess each individual's exposure to PM 10 , PM 2.5 , black carbon (BC), and nitrogen dioxide (NO 2 ). Associations of UPP-age-R with these pollutants were investigated by mixed models, accounting for clustering by residential address and confounders. Effect modifiers of the associations between UPP-age-R and air pollutants that included 18 factors reflecting vascular function, renal function, insulin resistance, lipid metabolism, or inflammation were evaluated. Direct and indirect (via UPP-age-R) effects of air pollution on mortality were evaluated by multivariable-adjusted Cox models.

RESULTS

Among 660 participants (50.2% women; mean age: 50.7 y), higher exposure to PM 10 , PM 2.5 , BC, and NO 2 was associated with a higher UPP-age-R. Studying effect modifiers showed that higher plasma levels of desphospho-uncarboxylated matrix Gla protein (dpucMGP), signifying poorer vitamin K status, steepened the slopes of UPP-age-R on the air pollutants. In further analyses among participants with dpucMGP ≥ 4.26 μ g / L (median), an interquartile range (IQR) higher level in PM 10 , PM 2.5 , BC, and NO 2 was associated with a higher UPP-age-R of 2.03 [95% confidence interval (CI): 0.60, 3.46], 2.22 (95% CI: 0.71, 3.74), 2.00 (95% CI: 0.56, 3.43), and 2.09 (95% CI: 0.77, 3.41) y, respectively. UPP-age-R was an indirect mediator of the associations of mortality with the air pollutants [multivariable-adjusted hazard ratios from 1.094 (95% CI: 1.000, 1.196) to 1.110 (95% CI: 1.007, 1.224)] in participants with a high dpucMGP, whereas no direct associations were observed.

DISCUSSION

Ambient air pollution was associated with accelerated urinary peptidomics aging, and high vitamin K status showed a potential protective effect in this population. Current guidelines are insufficient to decrease the adverse health effects of airborne pollutants, including healthy aging trajectories. https://doi.org/10.1289/EHP13414.

Recent Advances in Nutraceuticals for the Treatment of Sarcopenic Obesity

Sarcopenic obesity, low muscle mass, and high body fat are growing health concerns in the aging population. This review highlights the need for standardized criteria and explores nutraceuticals as potential therapeutic agents. Sarcopenic obesity is associated with insulin resistance, inflammation, hormonal changes, and reduced physical activity. These factors lead to impaired muscle activity, intramuscular fat accumulation, and reduced protein synthesis, resulting in muscle catabolism and increased fat mass. Myostatin and irisin are myokines that regulate muscle synthesis and energy expenditure, respectively. Nutritional supplementation with vitamin D and calcium is recommended for increasing muscle mass and reducing body fat content. Testosterone therapy decreases fat mass and improves muscle strength. Vitamin K, specifically menaquinone-4 (MK-4), improves mitochondrial function and reduces muscle damage. Irisin is a hormone secreted during exercise that enhances oxidative metabolism, prevents insulin resistance and obesity, and improves bone quality. Low-glycemic-index diets and green cardamom are potential methods for managing sarcopenic obesity. In conclusion, along with exercise and dietary support, nutraceuticals, such as vitamin D, calcium, vitamin K, and natural agonists of irisin or testosterone, can serve as promising future therapeutic alternatives.

Morphologic Evaluation of Dentoalveolar Structures after Corticotomy-Assisted Orthodontic Treatment in Romanian Adult Patients

Background and Objectives: Corticotomy-facilitated orthodontics is an approach that can be useful in treating complex orthodontic cases and that could enhance the rate of tooth movement. The aim of this study was to evaluate the changes that occurred in the buccal cortical bone and at the root level after an orthodontic treatment when corticotomy was used, in Romanian patients. Materials and Methods: After dividing the subjects into two groups (maxillary and mandibular corticotomy), based on CBCT, measurements were made of the thickness of the cortical buccal bone at the cervical, median and apical level, and of the root length at T0 (before corticotomy) and T1 (6 months after surgery). Several tests were used for statistical analysis of the data. Results: In the maxillary arch, the bone thickness measured after corticotomy in males was 0.64 mm at the cervical level, 0.53 mm at the medial level and 0.30 mm in the apical area. In females, the values were 0.46 mm (cervical), 0.37 mm (medial) and 0.36 mm (apical). In the lower arch, the values obtained for these three regions were 0.37 mm, 0.30 mm and 0.37 mm for males and 0.58 mm, 0.32 mm and 0.43 mm for female subjects. All values were statistically significant. The root length for the lower teeth at T0 was 11.98 ± 2.24 mm at T0 and 11.97 ± 2.24 mm at T1. For the upper teeth, the root length at T0 was 13.83 ± 2.28 mm and 13.81 ± 2.28 mm. Conclusions: Comparing the measurements, it was observed that the biggest changes in the cortical bone were at the cervical level. In the maxillary arch, the most significant modifications were registered at the canines and the level of the first premolars, and in the lower arch at the incisors level. The measured root resorption of the teeth was considered to be statistically insignificant.

Production of Vitamin K by Wild-Type and Engineered Microorganisms

Vitamin K is a fat-soluble vitamin that mainly exists as phylloquinone or menaquinone in nature. Vitamin K plays an important role in blood clotting and bone health in humans. For use as a nutraceutical, vitamin K is produced by natural extraction, chemical synthesis, and microbial fermentation. Natural extraction and chemical synthesis methods for vitamin K production have limitations, such as low yield of products and environmental concerns. Microbial fermentation is a more sustainable process for industrial production of natural vitamin K than two other methods. Recent advanced genetic technology facilitates industrial production of vitamin K by increasing the yield and productivity of microbial host strains. This review covers (i) general information about vitamin K and microbial host, (ii) current titers of vitamin K produced by wild-type microorganisms, and (iii) vitamin K production by engineered microorganisms, including the details of strain engineering strategies. Finally, current limitations and future directions for microbial production of vitamin K are also discussed.

Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins

In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.

The Biological Role of Vitamins in Athletes’ Muscle, Heart and Microbiota

Physical activity, combined with adequate nutrition, is considered a protective factor against cardiovascular disease, musculoskeletal disorders, and intestinal dysbiosis. Achieving optimal performance requires a significantly high energy expenditure, which must be correctly supplied to avoid the occurrence of diseases such as muscle injuries, oxidative stress, and heart pathologies, and a decrease in physical performance during competition. Moreover, in sports activities, the replenishment of water, vitamins, and minerals consumed during training is essential for safeguarding athletes’ health. In this scenario, vitamins play a pivotal role in numerous metabolic reactions and some muscle biochemical adaptation processes induced by sports activity. Vitamins are introduced to the diet because the human body is unable to produce these micronutrients. The aim of this review is to highlight the fundamental role of vitamin supplementation in physical activity. Above all, we focus on the roles of vitamins A, B6, D, E, and K in the prevention and treatment of cardiovascular disorders, muscle injuries, and regulation of the microbiome.

Effects of Extracellular Osteoanabolic Agents on the Endogenous Response of Osteoblastic Cells

The complex multidimensional skeletal organization can adapt its structure in accordance with external contexts, demonstrating excellent self-renewal capacity. Thus, optimal extracellular environmental properties are critical for bone regeneration and inextricably linked to the mechanical and biological states of bone. It is interesting to note that the microstructure of bone depends not only on genetic determinants (which control the bone remodeling loop through autocrine and paracrine signals) but also, more importantly, on the continuous response of cells to external mechanical cues. In particular, bone cells sense mechanical signals such as shear, tensile, loading and vibration, and once activated, they react by regulating bone anabolism. Although several specific surrounding conditions needed for osteoblast cells to specifically augment bone formation have been empirically discovered, most of the underlying biomechanical cellular processes underneath remain largely unknown. Nevertheless, exogenous stimuli of endogenous osteogenesis can be applied to promote the mineral apposition rate, bone formation, bone mass and bone strength, as well as expediting fracture repair and bone regeneration. The following review summarizes the latest studies related to the proliferation and differentiation of osteoblastic cells, enhanced by mechanical forces or supplemental signaling factors (such as trace metals, nutraceuticals, vitamins and exosomes), providing a thorough overview of the exogenous osteogenic agents which can be exploited to modulate and influence the mechanically induced anabolism of bone. Furthermore, this review aims to discuss the emerging role of extracellular stimuli in skeletal metabolism as well as their potential roles and provide new perspectives for the treatment of bone disorders.

Longitudinal Associations between Intake of Fruit and Vegetables and Height Attainment from Preschool to School Entry

To examine associations between fruit and vegetable intake in young childhood and height attainment during preschool and at school entry. Data for this study was based on "The Healthy Start" primary intervention study, which included 635 obesity-prone children, (58% boys), from the greater Copenhagen area, with a mean (SD) age of 4.0 (1.1) years (age range 2-6 years) at baseline. In the current study, 553 children (57% boys) were included with information on dietary intake at baseline and height measured at baseline (preschool age), and 511 children (56.8% boys) with the height measured at school entry (~6 years old). Height was measured by trained health professionals during the intervention and by school nurses at school entry. Information on intakes of fruit and vegetables, separately and combined, was gathered with four-day dietary records reported by parents. Participants were grouped into tertiles for their intakes at baseline. Compared to boys with low consumption, those with a moderate and high intakes of fruit and vegetables (F&V) had a greater attained height at preschool of 1.3 cm (95% confidence interval (CI): 0.3; 2.3) and at school entry of 2.4 cm (95% CI: 0.8; 3.9) and 1.8 cm (95% CI: 0.2; 3.4), respectively, also after adjustment for differences in age, body mass index (BMI), and total energy intake. Additional adjustment for mid-parental height and parents' education did not alter the significant associations between moderate consumption of F&V and attained height at preschool and school entry. There was no association among girls. Our results showed that a moderate consumption of F&V was directly associated with higher attainment in height at preschool and school entry in boys. From a public health perspective, it should be prioritized to continue developing intervention programs to improve fruit and vegetable intake.

Nutritional Status in Spanish Adults with Celiac Disease Following a Long-Term Gluten-Free Diet Is Similar to Non-Celiac

The only available treatment for celiac disease is life-long gluten exclusion. We conducted a cross-sectional age- and gender-matched study in 64 celiac adults on a long-term (>1 year) gluten-free diet and 74 non-celiac volunteers from Spain, using dietary, anthropometric, and biochemical parameters, as well as assessing bone mineral density and physical activity. Celiac adults had deficient intake (below 2/3 of the recommended intake) for folates, vitamin E, and iodine and low intake of calcium (below 80% of the recommended intake). Iron intake was also below 2/3 of the recommended intake in celiac women. Vitamin D intake was extremely low, and 34% of celiac patients had moderately deficient plasma levels. According to bone mineral density, celiac women may be more prone to osteopenia and osteoporosis. However, we found a perfectly analogous nutritional status scenario in celiac as compared to healthy volunteers, with the dietary deviations found being similar to those of the Spanish population, i.e., both groups followed a high-lipid, high-protein, and low-carbohydrate diet. Values for biochemical parameters were found within the reference ranges. Celiac disease had no influence on body weight, but body fat in celiac patients tended to be higher. According to our results, vitamin D, calcium, folates, vitamin E, iodine, and iron nutritional status should be specifically assessed and monitored in the celiac population.

Osteoporosis and the effect of dysregulation of the transsulfuration pathway via taurine on intracellular calcium homeostasis, vitamin D absorption and vitamin K absorption

BACKGROUND & AIMS

In this article we connect the dysregulation of the transsulfuration pathway to bone dysregulations and propose a novel treatment for osteoporosis. Current treatments for osteoporosis are very frequently inadequate. In osteoporosis, the risk of fractures increases with increased homocysteine (Hcy).

METHODS

Here, we conduct a review on the relationship between osteoporosis and the dysregulation of the transsulfuration pathway.

RESULTS

we show that the transsulfuration pathway metabolizes Hcy to L-cysteine. Increased Hcy levels point to the transsulfuration pathway being dysregulated. With the transsulfuration pathway dysregulated, there will be decreased levels of L-cysteine and decreased levels of taurine, which is synthesized from L-cysteine. Taurine levels are decreased in patients with osteoporosis. Taurine regulates intracellular calcium homeostasis. Taurine, also, when conjugated with bile acids assists with absorption of fats and fat-soluble vitamins such as vitamin D and vitamin K. Dysregulated calcium homeostasis, decreased calcium absorption and decreased absorption of vitamin D and vitamin K due to low levels of taurine negatively affect bone mineral density (BMD) leading to osteoporosis and fractures.

CONCLUSIONS

In this article, we propose that a combination of taurine, calcium, vitamin D and vitamin K, could increase BMD reducing number of years spent in disability and reducing deaths due to fractures in patients with osteoporosis.

Post-surgery cholecystectomy, hepatectomy, and pancreatectomy patients increase the risk of osteoporotic vertebral fracture

INTRODUCTION

Data is currently lacking regarding association between the cholecystectomy/hepatectomy/pancreatectomy and the development of osteoporotic fracture. A retrospective cohort study was conducted to investigate the relationship between cholecystectomy/hepatectomy/pancreatectomy and the subsequent risk of developing osteoporotic fracture.

MATERIALS AND METHODS

Patients having undergone cholecystectomy, hepatectomy, or pancreatectomy between 2000 and 2012 were selected from the All Population Based Hospitalization File as the surgery cohort (n = 304,081), which was frequency matched with the control cohort (n = 304,081). The Cox proportional hazard model and Kaplan-Meier analysis were applied to measure the hazard ratios and the cumulative incidence of osteoporotic fracture.

RESULTS

A total of 1136 patients in the surgery cohort and 1179 patients in the control cohort were newly diagnosed with osteoporotic fracture. The overall osteoporotic fracture risk in the surgery cohort was 1.12-fold higher [95% confidence interval (CI), 1.03-1.21]. Specifically, surgery cohort had higher vertebral fracture risk than non-surgery cohort [adjusted hazard ratio (aHR) 1.12, Cl, 1.03-1.22]. In addition, patients underwent cholecystectomy (includes open and laparoscopic approaches), hepatectomy (only open approach), and pancreatectomy group (only open approach) were 1.10 (95% CI, 1.01-1.19), 1.49 (95% CI, 1.10-2.01), and 1.88 (95% CI, 1.23-2.87) times more likely to develop osteoporotic fracture, respectively. No significant difference of osteoporotic fracture risk was observed between open and laparoscopic cholecystectomy. The risk of osteoporotic fracture was significantly increased in females, patients aged ≥ 40 years old, and patients with some comorbidity.

CONCLUSIONS

Patients post cholecystectomy, hepatectomy, or pancreatectomy significantly increased risk of developing osteoporotic fracture, suggesting closer attention in post-operative care is needed.

Calcium prescription by Indian orthopaedic surgeons: A survey and a review of literature

BACKGROUND

Orthopaedic surgeons prefer calcium supplement for various pathologies like fracture, osteoporosis, chronic musculoskeletal pain, yet there is no proper evidence to support the benefits of taking them regularly. The average requirement for calcium is around 500-1000 mg/day for a healthy adult, this amount of calcium is not achieved by diet, especially in developing countries like India. Despite this, the serum calcium level remains unaltered, due to the well-controlled absorption and excretion of calcium by the human body. As there is no clarity over the dose, duration and the prefered calcium salts, we constructed a survey to find the preferred dose, duration, the preferred calcium salts among orthopaedic surgeons, and to give an in-depth review of literature about dose, duration, timing, preferred calcium salt and various other calcium-related queries.

MATERIALS AND METHOD

The survey included 15 pre-structured questionnaires; these questions were formatted and validated by senior surgeons and other specialists after a through a review of calcium-related literature. These questionnaires were used in a pilot study conducted within the department and were later modified and separated into 7 sections. Data were collected by both online survey (google forms) and direct interviews.

RESULT AND CONCLUSION

128 Orthopedic surgeons responded. The total number of response obtained was 2355. Unanswered questions were 152. From the survey, it was found that most orthopaedic surgeons prefer to prescribe calcium routinely (55.46%). The commonly used calcium salt was calcium carbonate (47.65%), followed by citrate (32.8%). 42.18% were not aware of the efficiency of prescribing calcium in divided doses. Most responded that calcium is not to be given for patients with renal stones, but literature shows that calcium prescribed reduces the recurrence of commonest kidney stones, calcium oxalate stones.

Genetic Variation in VKORC1 and Risk for Osteoporosis

BACKGROUND AND AIMS

The vitamin K epoxide reductase complex subunit 1 (VKORC1) plays an important role in bone development and bone metabolism by influencing the vitamin K cycle. The aim of this study was to investigate the association between VKORC1 gene polymorphisms and bone mineral density and the risk of osteoporosis.

MATERIALS AND METHODS

We determined VKORC1 gene polymorphisms (rs9923231 and rs9934488) by using polymerase chain reaction-restriction and Sanger sequencing method in 606 postmenopausal women including 288 osteoporosis patients and 318 healthy controls.

RESULTS

No significant differences were observed in the rs9934488 polymorphisms between the osteoporosis group and controls. Subgroup analyses also indicated no positive result. VKORC1 rs9923231 polymorphism increased the risk of osteoporosis in the homozygous and allelic models. A significant correlation was observed in a subgroup of the elderly (age ≥55 years). Additionally, the genotypes of the rs9923231 polymorphism were significantly associated with low body mass index, and T-score, but not with age, serum calcium, or phosphorus.

CONCLUSIONS

In conclusion, VKORC1 rs9923231 polymorphism is a genetic contributor to osteoporosis risk and it should be confirmed in large well-designed studies.

Nutrient selection and optimization to formulate a nutrient bar stable on storage and specific to women at risk of osteoporosis

The objective of study was to select and characterize different food ingredients of plant origin and to optimize different levels of their formulations to develop nutrient bars; stable on storage and specific to women at risk of osteoporosis. After intensive literature review, ingredients selected include-cereal-mix of brown rice, oats and corn flakes, defatted soy flour, dried fruit mix of figs, dates and golden raisins, flaxseeds, two herbs namely dandelion leaves (Taraxicum officinale) and basil (Ocimum basilicum), honey and rice bran oil. Out of the 6 trials, total of 24 formulations were prepared to develop the bars. Tin moulds were used to shape and bake the bars, with standard temperature observed at 125 ± 5 °C for 25 ± 5 min. Selected ingredients showed high nutritional score on proximate and other nutrient analysis; four formulations of trail-VI got higher scores and were microbiologically safe. However, product showed some oxidative changes on storage. It was concluded that functional foods with healthy nutrients prepared for women at risk of osteoporosis not only aid in their bone health but are also commercially viable.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Biomarkers of Osteoporosis: An Update

Background:

Osteoporosis, characterized by compromised bone quality and strength is associated with bone fragility and fracture risk. Biomarkers are crucial for the diagnosis or prognosis of a disease as well as elucidating the mechanism of drug action and improve decision making.

Objective:

An exhaustive description of traditional markers including bone mineral density, vitamin D, alkaline phosphatase, along with potential markers such as microarchitectural determination, trabecular bone score, osteocalcin, etc. is provided in the current piece of work. This review provides insight into novel pathways such as the Wnt signaling pathway, neuro-osseous control, adipogenic hormonal imbalance, gut-bone axis, genetic markers and the role of inflammation that has been recently implicated in osteoporosis.

Methods:

We extensively reviewed articles from the following databases: PubMed, Medline and Science direct. The primary search was conducted using a combination of the following keywords: osteoporosis, bone, biomarkers, bone turnover markers, diagnosis, density, architecture, genetics, inflammation.

Conclusion:

Early diagnosis and intervention delay the development of disease and improve treatment outcome. Therefore, probing for novel biomarkers that are able to recognize people at high risk for developing osteoporosis is an effective way to improve the quality of life of patients and to understand the pathomechanism of the disease in a better way.

Metabolic Engineering of the MEP Pathway in Bacillus subtilis for Increased Biosynthesis of Menaquinone-7

Vitamin K is essential for blood coagulation and plays important roles in bone and cardiovascular health. Menaquinone-7 (MK-7) is one form of vitamin K that is especially useful due to its long half-life in the circulation. MK-7 is difficult to make via organic synthesis, and is thus commonly produced by fermentation. This study aimed to genetically modify Bacillus subtilis cultures to increase their MK-7 yield and reduce production costs. We constructed 12 different strains of B. subtilis 168 by overexpressing different combinations of the rate-limiting enzymes Dxs, Dxr, Idi, and MenA. We observed an 11-fold enhancement of production in the best-performing strain, resulting in 50 mg/L MK-7. Metabolite analysis revealed new bottlenecks in the pathway at IspG and IspH, which suggest avenues for further optimization. This work highlights the usefulness of Bacillus subtilis for industrial production of high value compounds.

Vitamin K-Dependent Matrix Gla Protein as Multifaceted Protector of Vascular and Tissue Integrity

Supplemental Digital Content is available in the text.

Central Hemodynamics in Relation to Circulating Desphospho-Uncarboxylated Matrix Gla Protein: A Population Study

Background Stiffening and calcification of the large arteries are forerunners of cardiovascular complications. MGP (Matrix Gla protein), which requires vitamin K-dependent activation, is a potent locally acting inhibitor of arterial calcification. We hypothesized that the central hemodynamic properties might be associated with inactive desphospho-uncarboxylated MGP (dp-uc MGP ). Methods and Results In 835 randomly recruited Flemish individuals (mean age, 49.7 years; 45.6% women), we measured plasma dp-uc MGP , using an ELISA -based assay. We derived central pulse pressure and carotid-femoral pulse wave velocity (PWV) from applanation tonometry and calculated forward and backward pulse waves using an automated, pressure-based wave separation analysis algorithm. Aortic PWV (n=657), central pulse pressure, forward pulse wave, and backward pulse wave mean± SD values were 7.34±1.64 m/s, 45.2±15.3 mm Hg, 33.2±10.2 mm Hg, and 21.8±8.6 mm Hg, respectively. The geometric mean plasma concentration of dp-uc MGP was 4.09 μg/L. All hemodynamic indexes increased across tertiles of dp-uc MGP distribution. In multivariable-adjusted analyses, a doubling of dp-uc MGP was associated with higher PWV (0.15 m/s; 95% CI, 0.01-0.28 m/s), central pulse pressure (1.70 mm Hg; 95% CI, 0.49-2.91 mm Hg), forward pulse wave (0.93 mm Hg; 95% CI, 0.01-1.84 mm Hg), and backward pulse wave (0.71 mm Hg; 95% CI, 0.11-1.30 mm Hg). Categorization of aortic PWV by tertiles of its distribution highlighted a decreasing trend of PWV at low dp-uc MGP (<3.35 μg/L) and an increasing trend at high dp-uc MGP (≥5.31 μg/L). Conclusions In people representative for the general population, higher inactive dp-uc MGP was associated with greater PWV , central pulse pressure, forward pulse wave, and backward pulse wave. These observations highlight new avenues for preserving vascular integrity and preventing cardiovascular complications (eg, by improving a person's vitamin K status).

Vitamin K2-Dependent GGCX and MGP Are Required for Homeostatic Calcium Regulation of Sperm Maturation

A low-calcium microenvironment is essential for spermatozoa to mature in the epididymis; however, it remains unclear how dysregulation of epididymal luminal calcium is associated with male infertility. Using a warfarin-induced vitamin K2 deficiency rat model, we found that vitamin-K-dependent γ-glutamyl carboxylase (GGCX) and matrix Gla protein (MGP) were essential in extracellular calcium signaling of the intercellular communication required for epididymal sperm maturation. We found that GGCX and MGP co-localized in the vesicular structures of epididymal cells and spermatozoa. Calcium-regulated MGP binds to proteins in a biphasic manner; sub-millimolar calcium enhances, whereas excessive calcium inhibits, the binding. Bioinformatic analysis of the calcium-dependent MGP-bound proteome revealed that vesicle-mediated transport and membrane trafficking underlie the intercellular communication networks. We also identified an SNP mutation, rs699664, in the GGCX gene of infertile men with asthenozoospermia. Overall, we revealed that the GGCX-MGP system is integrated with the intercellular calcium signaling to promote sperm maturation.

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Epididymal sperm maturation requires VK2-dependent GGCX-mediated MGP carboxylation

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A GGCX SNP mutation is found in infertile men suffering from asthenozoospermia

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Carboxylated-MGP regulates intercellular calcium signaling in the epididymal lumen

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Calcium-regulated MGP binds to proteins in a biphasic-manner and favors low levels

Bone mineral density and vitamin K status in children with celiac disease: Is there a relation?

BACKGROUND/AIMS

To investigate bone mineral density (BMD) in children with celiac disease (CD) and to evaluate the association between vitamin K levels and osteoporosis.

MATERIALS AND METHODS

Children with CD and age- and sex-matched healthy control subjects were prospectively included in the study. BMD was measured, and serum anti-tissue transglutaminase IgA, ferritin, folate, vitamin B12, 25-hydroxy vitamin D and K2, calcium, phosphate, alkaline phosphatase, and parathormone were assayed in all subjects.

RESULTS

Overall, 72 patients (mean age 11.69±3 years, 59.7% female) and 30 healthy subjects (mean age 12.27±2.12 years, 63.3% female) were enrolled. The mean BMD Z score of the celiac group was significantly lower than that of the control group (-1.23±1.07 vs. -0.35±1.04, p=0.001). Vitamin D and K2 values did not differ significantly between the two groups (p > 0.05). BMD was positively correlated with vitamin D (r=0.198, p=0.001) and negatively with PTH (r=-0.397, p=0.002).

CONCLUSION

The BMD of celiac patients was lower than that of the control subjects. There was no difference in terms of vitamin D and K2 levels between the two groups. Further studies investigating the level and effect of vitamin K on bone in CD are needed.

Vitamins D and K as Factors Associated with Osteopathy in Chronic Pancreatitis: A Prospective Multicentre Study (P-BONE Study)

Background

Osteopathy is common in patients with chronic pancreatitis (CP), but previous studies carry several limitations. Vitamin K is essential for bone metabolism, but its role in this setting has never been investigated. Our aim is to assess the prevalence of osteoporosis and osteopenia in CP patients, and to investigate the association between osteopathy and CP features and nutritional parameters, especially vitamin D and K levels.

Methods

Multicentre cross-sectional study on CP patients diagnosed according to M-ANNHEIM criteria. Bone density was evaluated by dual-energy X-ray absorptiometry and pancreatic function by faecal elastase. Nutritional evaluation included vitamin D and vitamin K. Differences between patients with or without osteopathy were evaluated. The association between investigated variables and bone density were analysed with logistic regression analysis.

Results

In total, 211 CP patients were enrolled at eight Centres (67% men; mean age 60). In total, 18% had advanced-marked CP, 56% suffered from pancreatic exocrine insufficiency and disease aetiology was alcoholic in 43%. Vitamin D and K were deficient in 56% and 32%, respectively. Osteopenia was diagnosed in 42% and osteoporosis in 22%. In the multivariate analysis, female sex (OR 2.78), age (OR 1.07 per year) and higher BMI (OR 0.84) were associated with the presence of osteoporosis. In male patients, the only factor associated with osteoporosis was vitamin K deficiency (OR 4.23).

Conclusion

The present data confirm a high rate of osteopathy in CP patients and highlight the relevance of vitamin K deficiency as only factor associated with osteoporosis in male patients for the first time.

Analysis of Menaquinone-7 Content and Impurities in Oil and Non-Oil Dietary Supplements

Rapid, global technological development has caused the food industry to use concentrated food component sources like dietary supplements ever more commonly as part of the human diet. This study analysed the menaquinone-7 (MK-7) content of dietary supplements in oil capsule and hard tablet forms. A novel method for separating and measuring geometric isomers of MK-7 in dietary supplements was developed and validated. Eleven different isomers of cis/trans- menaquinone-7 were identified. Identification of cis/trans isomers was performed by combination of HPLC, UPLC and HRMS-QTOF detection, whereas their quantities were determined by DAD detection. The content of menaquinone impurities was ascertained, including cis/trans- menaquinone-6 isomers (5.5–16.9 µg per tablet/capsule) and cis/trans-menaquinone-7 isomers (70.9–218.7 µg tablet/capsule), which were most likely formed during the chemical synthesis of the menaquinone-7. The all-trans MK-7 content was lower than the isomeric form and often lower than what the labels declared. A new method of quantification, developed and validated for menaquinones in oil capsules, provided on average 90% recovery and a limit of quantification (LOQ) of approximately 1 µg mL⁻¹.

The risk of nephrolithiasis is causally related to inactive matrix Gla protein, a marker of vitamin K status: a Mendelian randomization study in a Flemish population

Background

Vitamin K (VK)-dependent γ-glutamate carboxylation and serine phosphorylation activate matrix Gla protein (MGP) to a potent locally acting inhibitor of calcification. Nephrolithiasis represents a process of unwanted calcification associated with substantial mortality and high recurrence rates. We hypothesized that the risk of nephrolithiasis increases with VK shortage, as exemplified by higher plasma levels of desphospho-uncarboxylated MGP (dp-ucMGP).

Methods

In 1748 randomly recruited Flemish individuals (51.1% women; mean age 46.8 years), we determined dp-ucMGP and the prevalence of nephrolithiasis at baseline (April 1996-February 2015) and its incidence during follow-up until March 2016. We estimated the multivariable-adjusted relative risk associated with the doubling of dp-ucMGP, using logistic or Cox regression. We did a Mendelian randomization analysis using four MGP genotypes as instrumental variables.

Results

With adjustments applied for sex, age and 24-h urinary volume and calcium excretion, the odds of having prevalent nephrolithiasis [n = 144 (8.2%)] associated with dp-ucMGP was 1.31 [95% confidence interval (CI) 1.04-1.64; P = 0.022]. dp-ucMGP levels were associated (P ≤ 0.001) with MGP variants rs2098435, rs4236 and rs2430692. In the Mendelian analysis, the causal odds ratio was 3.82 (95% CI 1.15-12.7; P = 0.029). The incidence of nephrolithiasis over 12.0 years (median) was 37 cases (0.2%). With similar adjustments as before, the hazard ratio in relation to dp-ucMGP was 2.48 (95% CI 1.71-3.61; P < 0.001). Additional adjustment for a nephrolithiasis propensity score produced consistent results.

Conclusion

Higher levels of inactive dp-ucMGP may be causally associated with the risk of nephrolithiasis. Whether or not VK deficiency plays a role in these observations remains to be firmly established.

Therapeutic warfarin use and the extrahepatic functions of vitamin K-dependent proteins

The impact of warfarin therapy on the functions of extrahepatic vitamin K-dependent proteins (VKDP) is less clearly understood and less widely recognised in clinical practice than that on the hepatic counterparts (clotting factors II, VII, IX and X). Warfarin inhibits osteocalcin, an abundant extrahepatic VKDP involved in the mineralisation and maturation of bone and thus, primarily by this mechanism, may have an adverse effect on bone health. Whilst some studies do link warfarin use to an increase in osteoporosis and fracture risk others have not. Warfarin also inhibits the extrahepatic VKDP matrix gla protein (MGP) which acts to prevent ectopic calcification of the vasculature. Studies have consistently found a correlation between warfarin use and vascular calcification with inhibition of MGP believed to be the main cause. Inhibition of MGP also appears to explain warfarin's well established teratogenic effect. Further adverse effects may also arise from warfarin's inhibition of other known extrahepatic VKDPs. The available evidence is intriguing, and suggests that the impact of warfarin on the extrahepatic functions of vitamin K-dependent proteins warrants further careful consideration.

Vitamin K and osteoporosis: Myth or reality?

Vitamin K is a liposoluble vitamin. The predominant dietary form, phylloquinone or vitamin K1, is found in plants and green vegetables; whereas menaquinone, or vitamin K2, is endogenously synthesized by intestinal bacteria and includes several subtypes that differ in side chain length. Aside from its established role in blood clotting, several studies now support a critical function of vitamin K in improving bone health. Vitamin K is in fact required for osteocalcin carboxylation that in turn regulates bone mineral accretion; it seems to promote the transition of osteoblasts to osteocytes and also limits the process of osteoclastogenesis. Several observational and interventional studies have examined the relationship between vitamin K and bone metabolism, but findings are conflicting and unclear. This systematic review aims to investigate the impact of vitamin K (plasma levels, dietary intake, and oral supplementation) on bone health with a particular interest in bone remodeling, mineral density and fragility fractures.

An exploration of the bone health of older adults with an intellectual disability in Ireland

BACKGROUND

Many risk factors have been confirmed for poor bone health among the general population including age, gender and corticosteroid use. There is a paucity of investigation among people with intellectual disability; however, research points to differing risks namely anti-epileptic medication use, Down syndrome and poor behaviour lifestyle.

METHODS

Data was extracted from the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing in Ireland. In total, 753 participants took part, and data was gathered on participants' health status, behavioural health, health screenings and activities of daily living. The prevalence of osteoporosis and related risk factors were specifically examined.

RESULTS

Overall, 8.1% reported a doctor's diagnosis of osteoporosis with over 20% reporting history of fracture. Risk identified included older age (P < 0.0001), female gender (P < 0.0001), difficulty walking (P < 0.0001) with older age and being female the stronger predictors for osteoporosis, odds ratio = 6.53; 95% confidence interval 2.82-15.11 and odds ratio = 4.58; 95% confidence interval 2.29-9.17, respectively. There was no gender difference regarding the level of fractures; however, epilepsy and anti-epileptic medication were strong predictors. Overall, 11.1% attended for bone screening diagnostics.

CONCLUSION

Despite low levels of reported doctor's diagnosis of osteoporosis risk factor prevalence was high. Considering the insidious nature of osteoporosis and the low levels of diagnostic screening, prevalence could be possibly higher.

Are milk and alternatives and fruit and vegetable intakes during adolescence associated with cortical and trabecular bone structure, density, and strength in adulthood?

We investigated the impact of food group intake during adolescence on bone structure and strength during adulthood. In females, we found a beneficial effect of adolescent milk and alternatives and fruit and vegetable intake on adult radius shaft and distal tibia bone structure, respectively. No association was observed in males.

INTRODUCTION

The purpose of this study was to investigate whether adolescents with high intake of milk and alternatives (M&A) or fruit and vegetables (F&V) had better adult bone structure and strength compared to those with low intake levels.

METHODS

We analyzed data from 47 males and 69 females enrolled in the Pediatric Bone Mineral Accrual Study (PBMAS 1991-2011), who had one peripheral quantitative computed tomography scan at age 29 ± 2 years. We measured radius and tibia shaft total area (ToA), cortical area (CoA), cortical content (CoC), cortical density, bone strength (SSI_p), and muscle area, as well as distal radius and tibia ToA, total density, trabecular area, trabecular content, trabecular density, and bone strength (BSI_c). Sequential 24-h recalls were used to assess M&A and F&V intake; participants were grouped for their mean intake during adolescence (low = bottom quartile, moderate = middle quartiles, high = top quartile) and were compared using multivariate analysis of covariance while adjusting for adult height, muscle area, physical activity, energy and calcium intake and adolescent energy intake, and physical activity.

RESULTS

Females with high M&A intake compared to low M&A intake group (mean 3.8 vs. 1.3 servings/day, respectively) had greater adult ToA (14 %, p < 0.05), CoA (15 %, p < 0.01), and CoC (16 %, p < 0.01) at radius shaft. Females with moderate F&V intake compared to low F&V intake group (mean 3.7 vs. 2.1 servings/day, respectively) had greater adult ToA (8.5 %, p < 0.05) at distal tibia.

CONCLUSION

Higher intake of M&A or F&V during adolescence had a long-term beneficial effect on bone structure in females, an association not observed in males.

Bone Health and Osteoporosis: The Role of Vitamin K and Potential Antagonism by Anticoagulants

BACKGROUND

Vitamin K's effects extend beyond blood clotting to include a role in bone metabolism and potential protection against osteoporosis. Vitamin K is required for the gamma-carboxylation of osteocalcin. Likewise, this gamma-carboxylation also occurs in the liver for several coagulation proteins. This mechanism is interrupted by coumarin-based anticoagulants in both the liver and bone.

METHODS

A thorough review of the literature on vitamin K, osteocalcin and their role in bone metabolism and osteoporosis, as well as the potential bone effects of anticoagulant therapy was conducted.

CONCLUSIONS

Epidemiological studies and clinical trials consistently indicate that vitamin K has a positive effect on bone mineral density and decreases fracture risk. Typical dietary intakes of vitamin K are below the levels associated with better BMD and reduced fracture risk; thus issues of increasing dietary intakes, supplementation, and/or fortification arise. To effectively address these issues, large-scale, intervention trials of vitamin K are needed. The effects of coumarin-based anticoagulants on bone health are more ambiguous, with retrospective studies suggesting that long-term therapy adversely affects vertebral BMD and fracture risk. Anticoagulants that do not affect vitamin K metabolism are now available and make clinical trials feasible to answer the question of whether coumarins adversely affect bone. The research suggests that at a minimum, clinicians should carefully assess anticoagulated patients for osteoporosis risk, monitor BMD, and refer them to dietitians for dietary and supplement advice on bone health. Further research is needed to make more efficacious decisions about vitamin K intake, anticoagulant therapy, and bone health.

Adequate Dosing of Micronutrients for Different Age Groups in the Life Cycle

Many studies of micronutrient supplementation in developing countries have used single-nutrient supplements with either vitamins or minerals. However, people in these countries often suffer from multiple, rather than single, micronutrient deficiencies. The objective of this paper is to discuss the factors that go into determining the adequate dosing of vitamins and/or minerals for people of different ages. To elaborate on the adequacy of micronutrient doses in supplements, a model described by the US FNB was used, which calculates the difference between the mean observed intake for an individual and the estimated average requirement for a life stage and gender group. This model allows estimating the degree of confidence that a certain nutrient intake (from supplements and diet) is adequate. The US/Canadian DRI values have been used as the basis for these calculations, from which it can be concluded that a daily supplement of one RDA of each micronutrient is adequate to cover the personal requirements of all individuals in each respective age and gender group of the population, provided that 20 to 40% of an RDA is supplied by the diet—likely a realistic value for developing countries.

DRI values vary significantly between different age groups, reflecting changing needs over a life cycle. With the objective of a supplement to be adequate and safe, the design of a one-for-all supplement covering all age groups is not realistic. Such a supplement would either underscore or surpass the required intake of some of the age groups. Additionally the dosage of certain micronutrients might exceed the upper level of intake for lower age groups. Therefore, it is suggested that three different supplements following the one RDA concept for all micronutrients be developed for research use in developing countries for the following age groups: 1 to 3 years, 4 to 13 years, and females >14 years (excluding during pregnancy).

Vitamin-K-Dependent Protection of the Renal Microvasculature: Histopathological Studies in Normal and Diseased Kidneys

Vitamin-K-dependent carboxylation of matrix Gla protein (MGP) protects the macrocirculation against calcification. We recently reported in a multiethnic population study that the estimated glomerular filtration rate, a microvascular trait, decreased and the risk of chronic kidney disease increased with higher circulating levels of inactive dephospho-uncarboxylated MGP, a marker of vitamin K deficiency. These findings highlighted the possibility that vitamin K might have a beneficial effect on the renal microcirculation. To substantiate these epidemiological findings, we undertook a pilot study, in which we stained renal tissue samples obtained by biopsy from 2 healthy kidney donors and 4 patients with nephropathy for carboxylated and uncarboxylated MGP and calcium deposits. Three patients had renal calcifications, which were consistently associated with carboxylated and uncarboxylated MGP. Normal renal tissue was devoid of microcalcifications and staining for carboxylated and uncarboxylated MGP. Pending confirmation in a larger study covering a wider range of renal pathologies, these histopathological findings suggest that MGP might inhibit calcification not only in large arteries, as was known before, but in renal tissue as well, thereby highlighting potentially new avenues for promoting renal health, for instance by vitamin K supplementation.

Carboxylic Derivatives of Vitamin K2 Inhibit Hepatocellular Carcinoma Cell Growth through Caspase/Transglutaminase-Related Signaling Pathways

Chemoprevention of hepatocellular carcinoma (HCC) is one of the most challenging aspects of medical research. Vitamin K2 (VK2) has been suggested for its chemopreventive role in treatment of HCC, while inconsistent results in clinical trials have been reported. The present study was initiated to add to our insight into the anti-HCC cell proliferative effect of VK2 and its derivatives from a viewpoint of chemical structure. No significant effect was observed with original VK2, while VK2 derivatives bearing both isoprene units and a carboxyl-terminated side chain dose-dependently inhibited the growth of HCC cells without affecting normal liver cells. Loss-of-function analyses revealed that the anti-HCC cell activity by the VK2 derivatives was not mediated by a VK2 binding protein Bcl-2 homologous antagonist/killer (Bak) but rather associated with caspase/transglutaminase-related signaling pathways. Further studies on the carboxylic derivatives of VK2 bearing isoprene structural units introduced in this study might shed new light on the systemic treatment and prevention of HCC.

Antiosteoporotic effect of Petroselinum crispum, Ocimum basilicum and Cichorium intybus L. in glucocorticoid-induced osteoporosis in rats

BACKGROUND

Glucocorticoid-induced osteoporosis (GIO) is one of the serious side effects which have become the most common secondary osteoporosis. The purpose of this study is to evaluate the effect of aqueous extract of parsley, basil and chicory on glucocorticoid-induced osteoporosis in rats.

METHODS

Fifty Female rats were divided into five groups and treated for 8 weeks as follow: group 1 served as control; group (2) subcutaneously injected with 0.1 mg/kg b. wt. dexamethasone dissolved in saline; group 3 received similar dose of dexamethasone together with aqueous parsley extract in a dose of 2 g/kg b. wt.; group 4 received similar dose of dexamethasone together with 400 mg/kg b. wt. aqueous basil extract and group 5 received similar dose of dexamethasone together with 100 mg/kg b. wt. aqueous chicory extract.

RESULTS

The dexamethasone group showed a significant decrease in serum E2, Ca, P levels and significant decrease in total BMD, BMC and a significant increase in serum PTH, ALP and ACP. Bone TBARs was significantly increased while GSH, antioxidant enzymes were significantly decreased. These changes were attenuated by parsley, basil and chicory extracts in the group 3, 4 and 5 respectively.

CONCLUSION

Aqueous extracts of parsley, basil and chicory showed bone protection against glucocorticoid-induced in rats. From our results, we concluded that chicory has a potent protective effect more than parsley and basil due to containing flavonoids and inulin.

Effects of dietary lead exposure on vitamin levels in great tit nestlings - An experimental manipulation

Exposure to metal pollution negatively affects animal physiology, including nutrient metabolism, but in the wild an effect can seldom be attributed to a single metal. Moreover, little is known about how the metabolism of vitamins, essential micronutrients for developing juveniles, is affected by toxic metals. Therefore we experimentally investigated the effects of lead (Pb), a widespread toxic metal, on four fat-soluble vitamins A (total and retinol), D3, E (total and α-tocopherol) and K and carotenoids (lutein, zeaxanthin and unidentified) in great tit (Parus major) nestlings. In addition to a control group where no Pb was provided, two Pb-dosed groups were compared to a metal exposed group in the vicinity of a Ni-Cu smelter. We examined whether Pb treatment affects vitamin homeostasis and how the response of Pb-treated birds relates to that of a population under industrial exposure of Pb and other metals. For this purpose, vitamin and carotenoid levels were quantified with UPLC-MS from plasma of 7 days-old nestlings. All metal exposed groups showed increased vitamin A and retinol levels. However, vitamin levels were not directly associated with fecal Pb levels, with the exception of retinol, which was positively correlated with fecal Pb. Alpha-tocopherol, lutein and zeaxanthin levels were positively associated with body mass and wing growth rate. To conclude, Pb exposure increased plasma vitamin A and retinol levels while the levels of other vitamins and carotenoids rather reflected secondary pollution effects via differences in habitat and diet quality at the smelter site. Our findings suggest Pb exposed nestlings may allocate the vitamins needed for growth and development to fight the physiological stress thus compromising their fitness.

[A Systematic Review of the Acceptable Intake Level of Vitamin K among Warfarin Users]

The interaction of warfarin and vitamin K is a clinically significant issue. This study investigated the acceptable intake level of vitamin K among warfarin users by means of a systematic review. We searched two databases (PubMed and "Igaku chuo zasshi")for articles about adverse events arising from interaction of warfarin and vitamin K, published until October 2014. Of 1,310 citations retrieved, 16 studies met the selection criteria for examination of the upper limit, and 6 studies dealt with amounts below the limit. The intake of vitamin K in warfarin patients was acceptable in the range of 25-325 μg/day, with a maximum daily variation of 292 μg, and a value of 150 μg/day seemed optimum. When these results were applied to usual foods, except for dietary supplements or health foods, the only prohibited foods were fermented soybean (natto) and foods containing it, while green leafy vegetables could be acceptable if their intake is limited.

Vitamin K Dependent Protection of Renal Function in Multi-ethnic Population Studies

BACKGROUND

Following activation by vitamin K (VK), matrix Gla protein (MGP) inhibits arterial calcification, but its role in preserving renal function remains unknown.

METHODS

In 1166 white Flemish (mean age, 38.2 years) and 714 South Africans (49.2% black; 40.6 years), we correlated estimated glomerular filtration (eGFR [CKD-EPI formula]) and stage of chronic kidney disease (CKD [KDOQI stages 2-3]) with inactive desphospho-uncarboxylated MGP (dp-ucMGP), using multivariable linear and logistic regression.

RESULTS

Among Flemish and white and black Africans, between-group differences in eGFR (90, 100 and 122 mL/min/1.73 m(2)), dp-ucMGP (3.7, 6.5 and 3.2 μg/L), and CKD prevalence (53.5, 28.7 and 10.5%) were significant, but associations of eGFR with dp-ucMGP did not differ among ethnicities (P ≥ 0.075). For a doubling of dp-ucMGP, eGFR decreased by 1.5 (P = 0.023), 1.0 (P = 0.56), 2.8 (P = 0.0012) and 2.1 (P < 0.0001) mL/min/1.73 m(2) in Flemish, white Africans, black Africans and all participants combined; the odds ratios for moving up one CKD stage were 1.17 (P = 0.033), 1.03 (P = 0.87), 1.29 (P = 0.12) and 1.17 (P = 0.011), respectively.

INTERPRETATION

In the general population, eGFR decreases and CKD risk increases with higher dp-ucMGP, a marker of VK deficiency. These findings highlight the possibility that VK supplementation might promote renal health.