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Objective: To investigate the association of serum pigment epithelium-derived factor (PEDF) level and polymorphisms in PEDF gene promoter region -358G→A with non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM) of Han Nationality in Fujian Province., Methods: A total of 282 T2DM patients with NAFLD (DM1 group) and 170 age- and gender-matched T2DM patients without NAFLD (DM2 group) were examined for PEDF gene SNP-358G→A polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum pigment epithelium-derived factor(PEDF) level, fasting plasma glucose (FPG), fasting insulin (FINS) and glycosylated hemoglobin (HbA1c) were also measured., Results: The patients in DM1 group showed a significantly higher mean level of serum PEDF than those in DM2 group (P<0.05). Logistic regression analysis revealed that PEDF level was an independent risk factor for NAFLD in T2DM. The frequencies of PEDF gene -358G→A genotypes (GG, GA, and AA) and alleles (G/A) differed significanly between DM1 and DM2 groups (P<0.05). In terms of PEDF gene SNP -358G→A alleles, the GA genotype carriers had a 2.032 times higher risk of developing NAFLD compared with the GG genotype carriers, and the risk increased to 2.068 times in the carriers of the A allele (GA and AA genotypes; P<0.05)., Conclusion: Serum PEDF level is an independent risk factor of NAFLD in T2DM. Elevated serum PEDF level is a protective factor against insulin resistance. In T2DM patients, PEDF gene promoter region -358G→A polymorphism is associated with NAFLD, and the A allele contributes to an increased risk of NAFLD.

The mechanisms by which thyroid stimulating hormone (TSH) regulates the expression and activity of sodium iodide symporter (NIS) through cAMP-PKA have been partially elucidated by many studies. However, the effects of the TSH-mediated PLC-IP3 signaling pathway on the expression of NIS and how intracellular iodinated compounds interfere with these signaling pathways are poorly understood. In this study, we investigated the effects of the TSH-mediated cAMP-PKA and PLC-IP3 pathways on the expression of NIS in the presence of various intracellular iodinated compounds. The intracellular iodinated compounds were formed by treating cells with different concentrations of iodine with or without methimazole (MMI), an inhibitor of iodine organification, in a pig monolayer thyrocyte in vitro. A high concentration of iodine increased NIS expression at the mRNA and protein levels; however, this phenomenon was not observed in the presence of MMI. Both the cAMP-PKA and PLC-IP3 signaling pathways inhibited the expression of NIS at low iodine concentrations; however, in thyrocytes treated with high concentrations of iodine, the effect of cAMP-PKA on the expression of NIS changed from inhibition to promotion, while the PLC-IP3 pathway continued to inhibit NIS expression. These findings indicate that intracellular iodinated compounds affect NIS expression through the TSH-mediated cAMP-PKA and PLC-IP3 pathways.