Nutrition and Neurocognition Laboratory, JMUSDA HNRCA at Tufts University, Boston, MA 02111, USA.
J Nutr Biochem. 2010 Nov;21(11):1083-8. doi: 10.1016/j.jnutbio.2009.09.005. Epub 2010 Jan 25.
Dysregulation of myelin sulfatides is a risk factor for cognitive decline with age. Vitamin K is present in high concentrations in the brain and has been implicated in the regulation of sulfatide metabolism. Our objective was to investigate the age-related interrelation between dietary vitamin K and sulfatides in myelin fractions isolated from the brain regions of Fischer 344 male rats fed one of two dietary forms of vitamin K: phylloquinone or its hydrogenated form, 2',3'-dihydrophylloquinone (dK), for 28 days. Both dietary forms of vitamin K were converted to menaquinone-4 (MK-4) in the brain. The efficiency of dietary dK conversion to MK-4 compared to dietary phylloquinone was lower in the striatum and cortex, and was similar to that in the hippocampus. There were significant positive correlations between sulfatides and MK-4 in the hippocampus (phylloquinone-supplemented diet, 12 and 24 months; dK-supplemented diet, 12 months) and cortex (phylloquinone-supplemented diet, 12 and 24 months). No significant correlations were observed in the striatum. Furthermore, sulfatides in the hippocampus were significantly positively correlated with MK-4 in serum. This is the first attempt to establish and characterize a novel animal model that exploits the inability of dietary dK to convert to brain MK-4 to study the dietary effects of vitamin K on brain sulfatide in brain regions controlling motor and cognitive functions. Our findings suggest that this animal model may be useful for investigation of the effect of the dietary vitamin K on sulfatide metabolism, myelin structure and behavior functions.
髓鞘硫酸脂的失调是与年龄相关的认知能力下降的一个风险因素。维生素 K 在大脑中含量很高，并且已经涉及到硫酸脂代谢的调节。我们的目的是研究在喂食两种不同形式的维生素 K（叶绿醌或其氢化形式 2',3'-二氢叶绿醌（dK））的 Fischer 344 雄性大鼠的脑区髓鞘分离物中，饮食维生素 K 与硫酸脂之间的与年龄相关的相互关系。两种饮食形式的维生素 K 在大脑中都转化为甲萘醌-4（MK-4）。与饮食叶绿醌相比，dK 转化为 MK-4 的效率在纹状体和皮质中较低，而在海马中则相似。在海马体（补充叶绿醌的饮食，12 和 24 个月；补充 dK 的饮食，12 个月）和皮质（补充叶绿醌的饮食，12 和 24 个月）中，硫酸脂与 MK-4 之间存在显著的正相关关系。在纹状体中未观察到显著的相关性。此外，海马体中的硫酸脂与血清中的 MK-4 呈显著正相关。这是首次尝试建立和描述一种新型动物模型，该模型利用饮食 dK 无法转化为大脑 MK-4 的能力来研究饮食维生素 K 对控制运动和认知功能的脑区硫酸脂的影响。我们的研究结果表明，这种动物模型可能有助于研究饮食维生素 K 对硫酸脂代谢、髓鞘结构和行为功能的影响。
