Age- and brain region-specific effects of dietary vitamin K on myelin sulfatides.
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.
Crivello
Natalia A
NA
Nutrition and Neurocognition Laboratory, JMUSDA HNRCA at Tufts University, Boston, MA 02111, USA. natalia.crivello@tufts.edu
Casseus
Sherley L
SL
Peterson
James W
JW
Smith
Donald E
DE
Booth
Sarah L
SL
D000367:Age Factors; D000818:Animals; D001921:Brain / Q000378:metabolism*; D004032:Diet; D019587:Dietary Supplements; D008297:Male; D023421:Models, Animal; D009186:Myelin Sheath / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013433:Sulfoglycosphingolipids / Q000032:analysis / Q000378:metabolism*; D014812:Vitamin K / Q000008:administration & dosage* / Q000494:pharmacology*; D010837:Vitamin K 1 / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D024482:Vitamin K 2 / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology
D013433:Sulfoglycosphingolipids; C121368:dihydrophylloquinone; D024482:Vitamin K 2; D014812:Vitamin K; C030814:menatetrenone; D010837:Vitamin K 1