In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: Patient-prosthesis mismatch has been identified as a risk factor for mortality after aortic valve replacement and for structural valve deterioration (SVD) in patients receiving a bioprosthetic aortic valve. The aim of the present study was to compare the incidence of aortic valve bioprosthesis replacement for SVD in patients with mismatch to a population without mismatch.', 'Three hundred eighty-seven adult patients who underwent aortic valve replacement with a bioprosthesis from 1974 to 2009 were retrospectively reviewed. Mismatch was considered to be present if the anticipated indexed effective orifice area was <0.70\u2009cm(2) /m(2) . The median follow-up period was 7.2 years. Follow-up was 97% complete.', "Patient-prosthesis mismatch was present in 12% of the study population (n\u2009=\u200947). Ten-year freedom from reoperation for aortic bioprosthesis replacement was 74.3\u2009±\u20093.2%. During follow-up, 111 patients underwent reoperation for aortic bioprosthesis replacement. Causes of aortic bioprosthesis replacement were SVD of the bioprosthesis (n\u2009=\u200996), paravalvular leak (n\u2009=\u200910), and acute endocarditis (n\u2009=\u20095). According to unadjusted Kaplan-Meier analysis, patients with mismatch had a higher incidence of aortic bioprosthesis replacement for SVD when compared with patients without mismatch (log rank test: p 0.05). This result was confirmed by multivariable Cox regression analysis, which identified two independent predictors of aortic bioprosthesis replacement for SVD: patients' age (hazard ratio (HR) 0.967) and patient-prosthesis mismatch (HR 2.161).\Question: Does patient-prosthesis mismatch in patients undergoing bioprosthetic aortic valve implantation increase risk of reoperation for structural valve deterioration?

A: Patients suffering from mismatch were twice as likely to undergo reoperation for aortic bioprosthesis replacement for SVD than those without mismatch.
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Q: Context: The purpose of the present study was to investigate the potential signal mechanism of tissue factor (TF)\xa0in the regulation of the expression of vascular endothelial growth factor (VEGF) in human retinal pigment epithelial (ARPE-19) cells.', 'An in vitro RPE cell chemical hypoxia model was established by adding cobalt chloride (CoCl2) in the culture medium. The irritative concentration of CoCl2 was determined with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay kit. VEGF production in ARPE-19 cells was measured with enzyme-linked immunosorbent assay (ELISA) and western blotting. The Wnt signaling pathway-associated molecules, including phospho-glycogen synthase kinase 3β (p-GSK3β), GSK3β, p-β-catenin and β-catenin, were detected with western blotting. pEGFP-N3-hTF was constructed and verified with digestion of the restriction enzyme and sequencing analysis. Human TF overexpression and silencing plasmids were transfected into the ARPE-19 cells to clarify the causal relationship between TF and VEGF expression. The Transwell coculture system of ARPE-19 cells and RF/6A rhesus macaque choroid-retinal endothelial cells was performed to evaluate cell invasion and tube formation ability.', 'Our anoxic model of ARPE-19 cells showed that TF expression was upregulated in accordance with variations in hypoxia-inducible factor 1-alpha (HIF-1α) and VEGF levels. Silencing and overexpression of TF decreased and increased VEGF expression, respectively. The Wnt/β-catenin signaling pathway played an important role in this effect. Results from the ARPE-19 cell and RF/6A cell coculture system showed that the enhancement of TF expression in the ARPE-19 cells led to significantly faster invasion and stronger tube-forming ability of the RF/6A cells, while siRNA-mediated TF silencing caused the opposite effects. Pharmacological disruption of Wnt signaling IWR-1-endo inhibited the effects compared to the TF-overexpressing group, indicating the importance of the Wnt/β-catenin signaling pathway in the process of TF-induced VEGF expression and angiogenesis.\Question: Does tissue factor induce VEGF expression via activation of the Wnt/β-catenin signaling pathway in ARPE-19 cells?

A: Involvement of the activation of the Wnt/β-catenin signaling pathway is an important mediator for TF-induced VEGF production during the process of angiogenesis. Thus, our findings may ascertain the molecular regulation of TF in neovessel formation and show significant therapeutic implications.
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Q: Context: Gene therapy for severe von Willebrand disease (vWD) seems an interesting treatment alternative with long-term therapeutic potential. We investigated the feasibility of targeting the liver for ectopic expression of physiologically active von Willebrand factor (vWF).', 'The capacity of transgene-encoded murine vWF to restore vWF function was studied in a mouse model of severe vWD after liver-specific gene transfer by hydrodynamic injection. By using a hepatocyte-specific alpha1 antitrypsin promoter, a considerably higher and longer-lasting vWF expression was obtained when compared with a cytomegalovirus promoter, reaching maximum vWF plasma levels that are 10+/-1 times higher than the wild-type level. Liver-expressed vWF showed the full range of multimers, including the high molecular weight multimers, and restored factor VIII plasma levels, consistent with correction of the bleeding time 3 but not 7 days after gene transfer. Importantly, transgene encoded plasma vWF restored proper platelet adhesion and aggregation in a FeCl(3) induced thrombosis model.\Question: Is restoration of plasma von Willebrand factor deficiency sufficient to correct thrombus formation after gene therapy for severe von Willebrand disease?

A:
High ectopic expression of transgene encoded plasma vWF can be obtained after gene transfer to the liver. Liver-expressed vWF was fully multimerized and able to restore proper platelet plug formation in severe vWD. The liver therefore seems an attractive target for gene therapy for severe vWD.
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