Hepatocyte Growth Factor (HGF) Inhibits Collagen I and IV Synthesis in Hepatic Stellate Cells by miRNA-29 Induction

BACKGROUND: In chronic liver disease, hepatic stellate cells (HSC) transdifferentiate into myofibroblasts, promoting extracellular matrix (ECM) synthesis and deposition. Stimulation of HSC by transforming growth factor-β (TGF-β) is a crucial event in liver fibrogenesis due to its impact on myofibroblastic transition and ECM induction. In contrast, hepatocyte growth factor (HGF), exerts antifibrotic activities. Recently, miR-29 has been reported to be involved in ECM synthesis. We therefore studied the influence of HGF and TGF-β on the miR-29 collagen axis in HSC. METHODOLOGY: HSC, isolated from rats, were characterized for HGF and Met receptor expression by Real-Time PCR and Western blotting during culture induced myofibroblastic transition. Then, the levels of TGF-β, HGF, collagen-I and -IV mRNA, in addition to miR-29a and miR-29b were determined after HGF and TGF-β stimulation of HSC or after experimental fibrosis induced by bile-duct obstruction in rats. The interaction of miR-29 with 3'-untranslated mRNA regions (UTR) was analyzed by reporter assays. The repressive effect of miR-29 on collagen synthesis was studied in HSC treated with miR-29-mimicks by Real-Time PCR and immunoblotting. PRINCIPAL FINDINGS: The 3'-UTR of the collagen-1 and -4 subtypes were identified to bind miR-29. Hence, miR-29a/b overexpression in HSC resulted in a marked reduction of collagen-I and -IV synthesis. Conversely, a decrease in miR-29 levels is observed during collagen accumulation upon experimental fibrosis, in vivo, and after TGF-β stimulation of HSC, in vitro. Finally, we show that during myofibroblastic transition and TGF-β exposure the HGF-receptor, Met, is upregulated in HSC. Thus, whereas TGF-β stimulation leads to a reduction in miR-29 expression and de-repression of collagen synthesis, stimulation with HGF was definitely associated with highly elevated miR-29 levels and markedly repressed collagen-I and -IV synthesis. CONCLUSIONS: Upregulation of miRNA-29 by HGF and downregulation by TGF-β take part in the anti- or profibrogenic response of HSC, respectively

Surgical treatment of intracaval tumor relapse after radical tumor nephrectomy in locally advanced renal cell carcinoma

Background About 4-10% of patients with renal cell carcinoma (RCC) demonstrate intracaval tumor thrombi at the time of diagnosis. Furthermore, 2-3% of patients might develop local relapses of which intracaval recurrences represent a rare event with fewer than 15 cases reported in the literature. We report the diagnosis, surgical technique, perioperative complications, and oncological outcome in an additional 6 cases. Patients and methods Between 2008 and 2019, 6 patients were treated with isolated intracaval relapse of RCC. All patients had undergone radical nephrectomy with thrombectomy in the past. The mean time between first surgery and relapse was 45.2 (6-114) months and the mean age of patients was 75 (70-80) years: 2, 3 and 1 patient demonstrated thrombus level II, III, and IV, respectively. A thoracoabdominal and a transperitoneal surgical approach was chosen in 4 and 2 patients, respectively. Perioperative complications were reported according to the Clavien-Dindo classification. Relapse-free, cancer-specific and overall survival were calculated with the Kaplan-Meier method. Results The cava thrombus could be resected completely in all cases. The mean time of surgery was 330 (260-510) min and the mean blood loss was 1500 (300-6500) ml. Clavien-Dindo grade II and IV complications developed in 2 and 1 patients, respectively. The 90-day readmission rate and mortality were 0%. After a mean follow-up of 32.3 (6-96) months, 5 patients are relapse-free and 1 patient developed pulmonary and hepatic metastases managed by immuno-oncological therapy. One patient died 27 months postoperatively due to multiple myeloma. Conclusion Secondary thrombectomy for isolated intracaval tumor thrombus relapse represents a challenging surgery which is associated with a high oncological control rate and tolerable surgery-related morbidity. This type of surgery should be performed in centres with significant expertise in radical nephrectomy for locally advanced disease and thrombus surgery