青 未空

Several reports have indicated a possible link between decreasing plasma levels of vitamin K and bone mineral density. It has been suggested that intestinal bacteria contribute to maintenance of vitamin K. Several factors are involved in the reduction of vitamin K in patients with Crohn’s disease (CD). We aimed to assess the relationship between gut microbiota and alternative indicators of vitamin K deficiency in patients with CD. We collected the feces of 26 patients with clinically inactive CD. We extracted 16S rRNA from the intestinal bacteria in the feces and amplified it by polymerase chain reaction. The generated polymerase chain reaction product was analyzed using a 16S metagenomic approach by Illumina Miseq platform. Serum undercarboxylated osteocalcin concentration was used as an alternative indicator of vitamin K deficiency. There was a significant negative correlation between serum undercarboxylated osteocalcin and mean Chao1 index in cases of low activity. The diversity of the gut microbiota was significantly lower, and Ruminococcaceae and Lachnospiraceae were significantly decreased in the vitamin K-deficient group in comparison to the vitamin K-normal group. Taken together, these data suggested the significance of investigating the gut microbiota even in patients with clinically inactive CD for improving patients’ vitamin K status.

Background and Objectives: In Crohn's disease (CD), belonging to inflammatory bowel disease, the small intestine is involved in most cases. Most frequently affected is the distal ileum, where vitamin B-12 is specifically absorbed. Therefore, malabsorption of vitamin B-12 is quite likely to occur in patients with CD. In this study, we have studied the vitamin B-12 status in CD patients. Methods and Study Design: Forty eight patients with CD were evaluated for their food intake, and circulating concentrations of vitamin B-12, folic acid, and homocysteine (Hcy) as a sensitive marker for the insufficiency of these vitamins and a risk factor of atherosclerosis. Results: Plasma Hcy concentration was significantly correlated with serum vitamin B-12 concentration alone, and 60.4 % of the subjects had hyperhomocysteinemia. Receiver Operating Characteristics (ROC) analysis showed that serum concentration of vitamin B-12, but not folic acid, predicted hyperhomocysteinemia. Their intake of vitamin B-12 was much higher than the Japanese RDA, but not correlated with blood concentrations of vitamin B-12 or Hcy, probably due to malabsorption. Conclusions: Vitamin B-12 insufficiency and hyperhomocysteinemia were highly prevalent in CD patients. Recently, the significance of extra-intestinal complications of CD has been increasingly recognized, and our finding is likely to be of clinical importance.