Serum vitamin D is associated with non-alcoholic fatty liver disease in Chinese males with normal weight and liver enzymes.

AIM: Considering the characterization of vitamin D deficiency as a risk factor of ectopic fat deposition, the association of serum 25-hydroxy vitamin D3 [25(OH)D3] levels with non-alcoholic fatty liver disease (NAFLD) was evaluated in Chinese men with normal body mass index (BMI) and enzyme markers of liver function. METHODS: A total of 514 participants (22 to 79 years old) with normal BMI and liver enzymes were identified for analysis. Abdominal ultrasound was performed to diagnose NAFLD, and the fatty liver index (FLI) was calculated to quantify liver steatosis. Serum 25(OH)D3 levels were determined by an electrochemiluminescence immunoassay. RESULTS: Among the entire study population, the mean levels of serum 25(OH)D3 were 15.32±5.77 ng/mL. However, when serum 25(OH)D3 levels were compared between non-NAFLD subjects (n=438) and NAFLD subjects (n=76), the latter showed significantly lower levels (15.65±5.89 ng/mL vs 13.46±4.65 ng/mL, P=0.002). In addition, serum 25(OH)D3 levels were found to be significantly correlated with FLI after adjustment for age and BMI (r=-0.108, P=0.014). Logistic regression showed that serum 25(OH)D3 levels were independently correlated with NAFLD (OR: 0.937, 95% CI: 0.884-0.993, P=0.028). Furthermore, stepwise regression analysis revealed that serum 25(OH)D3 levels were inversely associated with FLI (ß=-0.055, P=0.040). CONCLUSION: The present study demonstrated that serum 25(OH)D3 levels were inversely associated with NAFLD, even in subjects with normal total body fat, suggesting a potential role of lower levels of vitamin D in the occurrence and development of NAFLD.

[Expression of methylthioadenosine phosphorylase (MTAP) gene and demethylation of its promoter in human colorectal cancer].

BACKGROUND AND OBJECTIVE: Abnormal expression of 5'-methylthioadenosine phosphorylase (MTAP) is found in various tumor tissues. This study was to explore the correlation of MTAP expression to demethylation of MTAP promoter in colorectal cancer tissues. METHODS: The contents of MTAP mRNA in 50 colorectal cancer tissue samples and the adjacent normal tissues were detected by real-time PCR; expression of MTAP protein was detected by immunohistochemistry; methylation of MTAP promoter in colorectal cancer tissues and its adjacent normal tissues were detected by methylation-specified PCR (MSP). RESULTS: Compared with the adjacent normal tissues, the expression of MTAP mRNA was dramatically increased in colorectal cancer tissues (P<0.01). The positive rate of MTAP protein in colorectal cancer was significantly higher than that in colorectal adenoma and in adjacent normal tissues (98.0% vs. 85.0% and 12.5%, P<0.05), and the difference of the latter two groups was also significantly different (P<0.01). The methylation frequency of MTAP promoter was significantly lower in colorectal cancer group (32.0%) than in normal tissue (93.8%) and colorectal adenoma (75.0%) groups (P<0.01). CONCLUSIONS: Expression of MTAP is significantly higher in human colorectal cancer than in normal colorectal tissues. Demethylation of MTAP promoter may play an important role in up-regulating MTAP expression.