ABSTRACT
Objective@#To investigate the role of piperine on the transformation of endothelial cells into fibroblasts.@*Methods@#Cultured human umbilical vein endothelial cells (HUVECs, 4-6 passage) were used for the main experiments. The transformation models of endothelial cells into fibroblasts were induced by transforming growth factor β (TGF-β) stimulation. HUVECs were divided into 6 groups: control group, TGF-β group and 4 groups treated with various concentrations of piperine (1, 5, 10, 20 μmol/L). CKK-8 was used to detect cell proliferation. The CD31/α-smooth muscle actin (α-SMA) expression level was detected by fluorescent staining. The vascular endothelial cadherin (VE-cadherin)/vimentin expression was detected by immunofluorescence staining. RT-PCR was used detect the mRNA expressions of transformation markers. Western blot was used to detect the protein expression of snail and twist.@*Results@#TGF-β increased HUVECs proliferation (P<0.05), which could be significantly inhibited by 10 and 20 μmol/L of piperine, but not by 1 and 5 μmol/L of piperine. Immunofluorescence results demonstrated that TGF-β increased HUVECs transformation to fibroblasts as shown by downregulated expression of endothelial markers CD31, VE-cadherin, and upregulated expression of α-SMA and vimentin, again, these effects could be attenuated by 10 and 20 μmol/L piperine. The expression levels of collagen type Ⅰ and type Ⅲ were significantly higher in TGF-β group than in control group (P<0.05), significantly lower in TGF-β+10 μmol/L piperine group and TGF-β+20 μmol/L piperine group than in TGF-β group (P<0.05).In addition, RT-PCR results showed that TGF-β increased mRNA expression of transformation markers (snail1, snail2, twist1, twist2), while 10 and 20 μmol/L of piperine could significantly downregulated the mRNA expressions of these markers. The protein expression levels of snail and twist were significantly higher in TGF-β group than in control group (both P<0.05), which was significantly lower in TGF-β+20 μmol/L piperine group than in TGF-β group (both P<0.05).@*Conclusions@#Piperine can inhibit the transformation of endothelial cells into fibroblasts. This effect might be viewed as one of the potential mechanisms of reduced myocardial fibrosis post piperine treatment.
ABSTRACT
Objective To determine the changes in serum and urine vitamin D binding protein ( VDBP) concentrations in type 2 diabetes, and to explore the clinical significance. Methods The serum and urine VDBP concentrations in 102 healthy individuals and 106 type 2 diabetic patients were determined by ELISA. For analysis and comparison, 106 type 2 diabetic patients were divided into imperfect glycemic control subgroup and perfect glycemic control subgroup, microalbuminuria subgroup and normal albuminuria subgroup. Results The cut-off point of serum VDBP concentrations was 60. 6 μg/ ml and the cut-off point of the urine ratio of VDBP and creatinine was 7. 76 mg/ g, and both were determined according to the upper limit of 97. 5 % credit intervals in 110 healthy individuals. Serum VDBP concentration and the urine ratio of VDBP to creatinine in type 2 diabetic patients were significantly higher than those in the healthy individuals ( P < 0. 01 ), the imperfect glycemic control subgroup had higher serum VDBP concentrations and the urine ratio of VDBP to creatinine than those in the perfect glycemic control subgroup ( P <0. 05). The microalbuminuria subgroup had higher urine ratio of VDBP to creatinine than that in the normal albuminuria subgroup ( P<0. 01). Urine ratio of VDBP to creatinine in diagnosing early diabetic nephropathy had sensitivity of 96. 4 % , specificity of 68 % , and concordance of 83% . Conclusion Detection of serum VDBP levels has some reference value in understanding the state of diabetes. Combined determinations of urine ratio of VDBP to creatinine and ratio of albumin to creatinine have significant clinical value in the early diagnosis of diabetic nephropathy.