[Effects of mesenchymal stem cell transplantation on growth of liver cancer: experiment with rats].

OBJECTIVE: To evaluate the effects of mesenchymal stem cell (MSC) transplantation on the growth of liver cancer. METHODS: MSCs were isolated from the bone marrows of SD rats. Walker-256 cancer cells were isolated from the cancerous ascites of rat and cultured. Forty-five SD rats were randomly divided into 3 equal groups: mixed transplantation group undergoing laparotomy and transplantation of cancer cells mixed with MSCs into the liver, MSC IV transplantation group undergoing injection of MSCs into the caudal vein, and control group undergoing only MSC transplantation into the liver. MR imaging was performed s at days 3, 6, 9 and 12 after modeling to measure the maximum cross section area of the tumor. At day 12 the rats were killed after MR imaging with their livers taken out to undergo HE staining and pathological examination. Immunohistochemistry was used to detect the expression of vascular endothelial cell growth factors (VEGF), nm23 gene, a tumor metastasis inhibiting gene, and proliferating cell nuclear antigen (PCNA), a nuclear polypeptide necessary in the DNA synthesis. RESULTS: No significant evidence of tumor formation was detected by MRI at days 3 and 6 after modeling in all rats and tumor nodules were observed since day 9. The maximum cross section areas of tumor of the mixed transplantation group and MSC IV transplantation group were significantly larger than that of the control group at days 9 and 12 (F = 4.21, P < 0.05; F = 8.52, P < 0.01). Immunohistochemistry showed that VEGF expression levels of the two study groups were both significantly higher than that of the control group (F = 9.58, P < 0.01), while the nm23 gene expression levels of the 2 study groups were both significantly lower than that of the control group (F = 4.61, P < 0.05). The PCNA expression level of the mixed transplantation group was significantly higher than that of the control group (d'((1, 0.05)) = 0.34, d'((1, 0.01)) = 0.63, P < 0.05), however, there was no significant difference in the PCNA expression level between the MSCs IV transplantation group and the control group (d'((1, 0.05)) = 0.32, d'((1, 0.01)) = 0.48, P > 0.05). There was no significant difference in the tumor apoptotic index between the 2 study groups and the control group (F = 1.25, P > 0.05). CONCLUSION: MSC transplantation increases the expression of VEGF and PCNA, while decreases the expression of nm23 gene in cancer cells, thus favoring the tumor growth.

Dynamic CT Evaluation of Tumor Vascularity in Renal Cell Carcinoma.

OBJECTIVE: The purpose of our study was to evaluate the correlation between the enhancement parameters of dynamic CT; the carcinoma tissue microvessel density (MVD, a hotspot method to provide a histologic assessment of tumor vascularity); and tumor nuclear grade in renal cell carcinomas. SUBJECTS AND METHODS: Twenty-four patients with histologically diagnosed renal cell carcinoma underwent dynamic enhanced CT. Enhancement parameters, slope of the time-density curve, the density difference before and after tissue enhancement (deltaH), tissue blood ratio (TBR), and area under the time-density curve (AR), were calculated for all lesions. Pathology slides corresponding to the CT plane were stained using mouse antihuman CD34 monoclonal antibody and H and E. Fuhrman nuclear grade was used. Vascular hot spots of microvessels were recorded. Spearman's rank correlation was performed to determine the strength of the relationship between enhancement parameters, MVD determinations, and tumor nuclear grade. RESULTS: MVD with CD34 staining revealed uneven distribution of positively stained vascular endothelial cells in renal cell carcinoma lesions. Heterogeneous distribution of contrast enhancement was seen among and within individual tumors. The tumors appeared as uneven patterns on time-density curves of renal cell carcinoma lesions. Enhancement parameters of H (median, 21.0 H; range, 2.2-105.8 H), TBR (median, 39%; range, 10.7-154.7%), AR (median, 1.58 H x sec; range, 0.23-3.67 H x sec), and slope (median, 2.76; range, 0.53-6.76) varied greatly. Renal cell carcinoma tissue MVD significantly correlated with all enhancement parameters of dynamic CT. The correlation coefficients (r) were 0.62, 0.54, 0.55, and 0.44, respectively, for delta H, slope, TBR, and AR (p < 0.0 5). All enhancement parameters did not significantly correlate with tumor nuclear grade. They were not predictive of nuclear grade. CONCLUSION: Enhancement parameters of dynamic CT may be suited to evaluate tumor vascularity in vivo. Dynamic enhanced CT images may reflect the heterogeneity of tumor angiogenesis on the basis of the correlation between enhancement parameters and MVD of renal cell carcinoma.