Phylloquinone transport and its influence on γ-carboxyglutamate residues of osteocalcin in patients on maintenance hemodialysis

Saupe, Jörg; Shearer, Martin J.; Kohlmeier, Martin

doi:10.1093/ajcn/58.2.204

Cited by 89 publications

(63 citation statements)

References 30 publications

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“…In our study, there were no associations between apoE genotype and plasma phylloquinone, in contrast to that previously described in hemodialysis patients (Saupe et al, 1993;Kohlmeier et al, 1998). This difference may be due to several factors including the greater range and lower intrasubject variance of plasma phylloquinone in these patients, their more controlled diet and presence of hyperlipidaemia in some patients Kohlmeier et al, 1998).…”

Section: Ethnic Differences In Osteocalcin C-carboxylation Sr Beavan contrasting

confidence: 99%

“…Previous studies have shown that circulating phylloquinone concentrations in hemodialysis patients followed the order of apoE24E34E4 (Saupe et al, 1993). It was postulated that this reflected apoE isoform-dependent clearance of phylloquinone-rich remnant lipoproteins by the liver in the order apoE44E34E2, which has been well established for retinyl ester-labelled remnants and may result in more phylloquinone richlipoprotein being available for uptake by bone in subjects with apoE2 (Saupe et al, 1993;Kohlmeier et al, 1998). However, in our study, apoE4 allele was not associated with an increase in adjusted ucOC.…”

Section: Ethnic Differences In Osteocalcin C-carboxylation Sr Beavan mentioning

confidence: 95%

“…Since plasma concentrations of phylloquinone are positively correlated with triacylglycerol (Sadowski et al, 1989;Saupe et al, 1993), we also measured plasma triacylglycerol concentrations using a COBAS analyser and enzymatic colorimetric kit method according to the manufacturer's instructions (Unimate 5, Roche, Lewes, UK). Duplicate measurements were made with kit and in-house controls.…”

Section: Plasma Phylloquinone and Triacylglycerolmentioning

confidence: 99%

“…The apoE gene is polymorphic, with three common alleles resulting in six genotypes (E2/2, E2/3, E2/4, E3/3, E3/4 and E4/4) (Davignon et al, 1988). ApoE genotype has been linked to the TRL-mediated transport of phylloquinone to bone (Saupe et al, 1993;Kohlmeier et al, 1997) and to osteoporotic fracture risk (Kohlmeier et al, 1998;Cauley et al, 1999) and low BMD (Shiraki et al, 1997), although not all studies find associations between apoE genotype and BMD or fracture risk (Booth et al, 2000, Heikkinen et al, 2000.…”

Section: Introductionmentioning

confidence: 99%

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Ethnic differences in osteocalcin γ-carboxylation, plasma phylloquinone (vitamin K1) and apolipoprotein E genotype

et al. 2004

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Objective: To investigate plasma osteocalcin g-carboxylation and its relationship to plasma phylloquinone concentration and apolipoprotein E (apoE) genotype in women from three ethnic groups with differing osteoporotic fracture risk. Design and subjects: Fasted blood samples were collected from postmenopausal Gambian (n ¼ 50), British (n ¼ 31) and Chinese women (n ¼ 23), and 11 premenopausal women in each group from three cross-sectional studies. Results: After adjustment for total osteocalcin, plasma undercarboxylated osteocalcin (adjusted ucOC) was lowest in Chinese and highest in British women postmenopause (British vs Chinese 103% higher, Po0.0001; Gambian vs Chinese 66% higher, Po0.01). No differences were observed premenopause. Within each ethnic group, adjusted ucOC was similar pre-and postmenopause. Postmenopause, plasma phylloquinone was higher in Chinese women (1.0 ng/ml) than in British (0.31 ng/ml) and Gambian women (0.36 ng/ml) (Po0.0001). Premenopause, plasma phylloquinone was higher in Gambian and Chinese women (0.6 ng/ml) than in British women (0.3 ng/ml; P ¼ 0.01). Plasma phylloquinone and adjusted ucOC were inversely related in postmenopausal British women (R 2 ¼ 32.4%; P ¼ 0.0008). ApoE4 frequency was Gambian 32.6%, British 13.8% and Chinese 6%. A lower adjusted ucOC was associated with apoE2 genotype in British and Chinese women. Ethnic differences in adjusted ucOC persisted after adjustment for phylloquinone and apoE genotype. Conclusion: These preliminary data indicate suboptimal vitamin K status in postmenopausal British compared to Chinese and Gambian women. Ethnic differences in apoE genotype may also influence osteocalcin g-carboxylation status. The study highlights the need for larger epidemiological investigations of ethnic differences in vitamin K status and the possible implications to bone health. Sponsorship: This work was funded by the MRC.

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Section: Ethnic Differences In Osteocalcin C-carboxylation Sr Beavan contrasting

confidence: 99%

Section: Ethnic Differences In Osteocalcin C-carboxylation Sr Beavan mentioning

confidence: 95%

Section: Plasma Phylloquinone and Triacylglycerolmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ethnic differences in osteocalcin γ-carboxylation, plasma phylloquinone (vitamin K1) and apolipoprotein E genotype

et al. 2004

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“…Celle-ci est la plus importante des protéines non collagéniques de l'os (1 % des protéines totales de l'os, mais 15 à 20 % des protéines non collagéniques). Elle possède trois résidus gammacarboxylés permettant la fixation des ions Ca 2+ et leur conférant une haute affinité pour l'hydroxyapatite [14].…”

Section: Vitamine K Et Osunclassified

Actualité sur la vitamine K

Guillaumont¹

2000

OCL

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Summary:The difficulty of quantifying vitamin K levels and determining the number of active molecules long impeded in investigations into the metabolism and physiological function of vitamin K. In the last ten years, since gamma carboxylation was first demonstrated, studies have essentially focused on: -vitamin K sources and requirements: the composition of foods and requirements with respect to molecules with vitamin K activity are beginning to be known; -vitamin K and bone: the role of osteocalcin in bone mineralization and its association with vitamin K have been studied, particularly in elderly subjects; -hemorrhagic disease of the newborn: after a number of controversies, it is now generally accepted that prophylactic treatment of all newborns should be systematic, and repeated for breast-fed infants. Vitamin K should be administerted orally except in cases of malabsorption. However, a number of essential questions remain unanswered, such as the precise role played by certain carboxyproteins (bone carboxyprotein or Gas6) and, in particular, the choice of markers for the accurate evaluation of vitamin K status in humans.Keywords: vitamin K, bone, newborn. ARTICLE Sources et besoinsIl existe assez peu de données précises sur la composition des aliments en vitamines en raison de la complexité du dosage. Ce dosage est basé sur la réduction du noyau quinone suivi d'une détection par fluorescence ou par électrochimie [6].Si la phylloquinone est présente dans de nombreux aliments, les concentrations sont faibles. Seuls les légumes verts comme les épinards, les choux et les brocolis contiennent des concentrations importantes de phylloquinone (tableau) [7].Les ménaquinones (MK7, 8 et 9) sont surtout retrouvées dans les foies d'animaux, les fromages, le lait caillé et les aliments fermentés comme la choucroute [8].La biodisponibilité de la vitamine K peut varier considérablement en fonction de la teneur en lipides et de la lipophilie des formes de la vitamine K [9].Les besoins en vitamine K sont donc difficiles à apprécier mais les auteurs sont néanmoins d'accord pour dire qu'ils sont extrêmement faibles car le mécanisme de recyclage est très efficace. Ils sont Article disponible sur le site http://www.ocl-journal.org ou http://dx

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