[Upregulated Notch1 expression promotes bone morphogenetic protein-2/4 expression of calcified human heart valve interstitial cells].

OBJECTIVE: To observe the protein expression of Notch1 in the cultured calcified human heart valve interstitial cells (hVICs) in vitro and related mechanisms. METHODS: hVICs were divided into two groups: control hVICs were cultured in conventional media for 14 days and calcified hVICs were cultured with calcification inducers: ß-glycerophosphate (500 µl), ascorbic acid (200 µl), dexamethasone(100 µl) for 7 days. The calcified hVICs were further divided into calcified hVICs group and inhibited calcified hVICs by adding specific Notch1 inhibitor DAPT (50 µmol/L(4 µl/hole))groups and cultured for another 7 days. Inflammatory response of all groups were induced by lipopolysaccharide (LPS) for 8 to 12 hours. Western blot was used to detect the protein expression of Notch1, phosphorylation nuclear transcription factor κB (p-NF-κB), bone morphogenetic protein-2/4(BMP-2/4). ELISA was applied to detect the content of BMP-2 secretion of the groups. Von Kossa staining was used to observe of cellular calcification. RESULTS: (1)Von Kossa staining is positive in the induced calcification group, the expression of Notch1, p-NF-κB, BMP-2 and BMP-4 is significantly higher in the induced calcification group than in the control group (all P<0.05). The expression of BMP-2 is significantly higher in the induced calcification group than in control group ((88.23±3.28) pg/ml vs. (25.41±3.68) pg/ml, P=0.02). (2) After treatment with DAPT, the calcification and the expression of Notch1, p-NF-κB, BMP-2 and BMP-4 were significantly decreased compared to calcification group (all P<0.05). The expression of BMP-2 is (26.74±4.62) pg/ml in the calcification inhibition group and (80.41±2.96) pg/ml in calcified control group (P=0.02). CONCLUSIONS: Upregulated Notch 1 expression promotes BMP-2/4 secretion in LPS stimulated hVICs, and contributes to osteogenic changes in hVICs. Inhibiting Notch1 can decrease the BMP-2/4 secretion and calcification in hVICs, which may serve as a novel therapeutic option for treating calcific valve disease.

Acute effect of calcium blocker on renal hemodynamics in diabetic spontaneously hypertensive rat.

This study was done to examine the acute effect of a calcium channel blocker on renal hemodynamics in the diabetic spontaneously hypertensive rat (SHR). Streptozotocin was used to induce diabetes, and barnidipine (B) was used as a calcium blocker. Renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by a clearance method with paraaminohypurate (PAH) and inulin, respectively. Rats were divided into two groups: nondiabetic SHR, N-SHR; diabetic SHR, DM-SHR. B increased RBF in N-SHR (7.44 +/- 1.99 versus 8.50 +/- 1.97 mL/min/g.kw) while there was no change in DM-SHR. B reduced renovascular resistance (RVR) in DM-SHR and N-SHR. B increased GFR in N-SHR (1.15 +/- 0.24 versus 1.34 +/- 0.25 mL/min/g.kw), in spite of no changes in DM-SHR. B did not modify filtration fraction (FF) in both groups. These results indicate (1) in SHR, B exerts beneficial effects on hypertensive renal damage by reducing mean arterial pressure (MAP), RVR, RBF, and GFR; (2) in diabetic SHR, B is less effective in restoring renal hyperfiltration in spite of reducing RVR.

The characteristics of renal hemodynamics in diabetic spontaneously hypertensive rats in comparison with diabetic Wistar-Kyoto rats.

Diabetic Sprague-Dawley (SD) rats are known to exhibit renal hyperfiltration and hyperperfusion accompanied by renal hypertrophy. We examined whether such characteristics of renal hemodynamics in diabetic SD rats are also observed in diabetic spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. SHR and WKY rats were divided into four groups: D-S, diabetic SHR; N-S, nondiabetic SHR; D-W, diabetic WKY rats; and N-W, nondiabetic WKY rats. Streptozotocin (STZ), 90 mg, was intraperitoneally injected to induce diabetes. Renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by a clearance method with paraaminohypurate and insulin, respectively, 7-12 days after diabetes induction. In D-S and D-W, there was no increase in the kidney weight and RBF, in spite of significant increases in GFR and fasting blood sugar levels. These results indicate that, in both WKY and SHR, diabetes does not always produce renal hypertrophy and does not result in an increase in RBF.