ABSTRACT
[Objective] Vascular calcification is a gene-regulated biological process similar to bone formation.It is very common in the patients with chronic kidney disease.Neutral sphingomyelinase 2 (nSMase2) is a key regulator of bone development,and is responsible for ceramide generation through sphingomyelin hydrolysis,but the role of nSMase2 in vascular calcification remains unclear.The aim of this study is to determine whether nSMase2 regulates high calcium and phosphate-induced calcification of vascular smooth muscle cells (VSMC).[Methods] In vitro model of human VSMC calcification was used in this study and high calcium and phosphate were used to induce calcification of VSMCs.GW4869 was used to inhibit nSMase2 activity and nSMase2 was knockdowned in cultured VSMC using nSMase2 siRNA.The expression of Runx2,BMP2 and Osterix was analyzed by qRT-PCR and calcification was assessed by alizarin red staining.[Results] We found that nSMase2 expression and ceramide levels were increased in the process of VSMC calcification (P＜0.05).Inhibition of nSMase2 activity by GW4869 and knockdown of nSMase2 attenuated high calcium and phosphate-induced VSMC calcification and down-regulated the expression level of Runx2,BMP2 and Osterix (P＜0.05).By contrast,ceramide accelerated rat VSMC calcification and increased ALP activity (P＜0.05).[Conclusion] We demonstrate that nSMase2/ceramide promotes high calcium and phosphate-induced VSMC calcification,suggesting that nSMase2/ceramide could participate in the progression of vascular calcification in patients with chronic kidney disease.
ABSTRACT
OBJECTIVE@#To investigate the relationship between the expression of vascular endothelial growth factor C (VEGF-C) and angiogenesis and lymphangiogenesis in papillary thyroid carcinoma (PTC).@*METHODS@#Seventy-two PTC cases were divided into 3 groups according to the level of invasion: papillary microcarcinoma group (PMC group), intrathyroid carcinoma group (IPC group), and extrathyroid carcinoma group (EPC group). They were again divided into 2 groups according to lymph node metastasis: lymph node metastasis group and lymph node no-metastasis group. The expressions of VEGF-C, CD105 and vascular endothelial growth factor receptor-3 (VEGFR-3) were detected by SP method of immunohistochemical staining. The expression of VEGF-C was analyzed quantitatively by image analysis system, and the PI of VEGF-C (VEGF-C-PI), the number of MVD (microvessel density), and LVD (lymphaticvessel density) were obtained.@*RESULTS@#The VEGF-C-PI of lymph node metastasis group (23.15 +/- 3.75) was higher than that of lymph node non-metastasis group (14.54 +/- 2.93) (P <0.01). MVD was 35.25 +/- 2.06 in the PMC group, 41.75 +/- 5.46 in the IPC group, and 52.58 +/- 4.16 in the EPC group, which showed the elevatory tendency with the increase of invasion (P < 00.5). LVD was 6.00 +/- 0.81 in the PMC group, 13.80 +/- 1.81 in the IPC group, and 19.17 +/- 2.96 in the EPC group, which again showed the elevatory tendency with the increase of invasion (P <0.05). The LVD of lymph node metastasis group (19.56 +/- 2.45) was significantly higher than that of lymph node non-metastasis group (12.48 +/- 2.84) (P < 0.05). VEGF-C was positively correlated with MVD and LVD (r = 0.743, 0.90, P <0.01).@*CONCLUSION@#The expressions of VEGF-C and LVD are related to lymph node metastasis of PTC. MVD and LVD are related to the invasion of PTC. VEGF-C may play an important role in the angiogenesis and lymphangiogenesis.