Objective To investigate the biological and biomechanical characteristics of acellular porcine aortic valve with dye mediated photo oxidation so that a new and better bioprosthetic valve materials can be obtained. Methods Thirty porcine aortic valves were divided into three groups with random number table. Acellular valves (n=10) were stabilized by dye mediated photo oxidation in dye mediated photo oxidation group; acellular valves (n=10) were stabilized by glutaraldehyde in glutaraldehyde group; and acellular valves (n=10) were acellularized only in acellular valves group. Thickness, appearance, histology, water content, shrinkage temperature, breaking strength and soluble protein level of acellular porcine aortic in three groups were tested respectively. Results There were light blue, soft, flexible and unshrinking valves in dye mediated photo oxidation group. Compared to valves in glutaraldehyde group, valves in dye mediated photo oxidation group had lighter thickness（0.26±0.09mm vs. 0.38±0.08mm，Plt;0.05）, more water content（86.30%±4.03% vs. 71.10%±3.23%，Plt;0.05）, and lower shrinkage temperature （76.30±0.70℃ vs. 87.70±0.30℃，Plt;0.05）; while these indexes had no statistically significant differences compared to those in acellular valves group. At the same time, compared to valves in acellular valves group, valves in dye mediated photo oxidation group had more breaking strength（17.33±2.65 mPa vs. 9.11±0.95 mPa，Plt;0.05） and lower soluble protein level（0.039%±0.013% vs. 0.107%±0.024%，Plt;0.05）; while these indexes had no statistically significant differences compared to those in glutaraldehyde group. Conclusion Acellular porcine aortic valve stabilized by dye mediated photo oxidation has nice biological and biomechanical characteristics.
Objective To explore morphological recellularization level of bioprosthetic valve scaffold (BVS) and to provide researching means for fabricating tissue engineered heart valve in vitro.Methods The homograft bioprosthetic aortic tube valve was selected as BVS, which was conserved by liquid nitrogen, and its endothelial cells (ECs) were removed by 0.1% sodium dodecylsulphate (SDS). As implantation cells, the endothelial cells (ECs) differentiating from human bone marrow mesenchymal stem cells (MSCs) in vitro were implanted with high-density seeding (gt;10 5 cells/cm2) on the BVS, which was covered by fibronectin (80 μg/ml) in advance. The complex structure was statically cultured in DMEM (high glucose) with 20% FBS and VEGF (10 ng/ml) for about 20 days in vitro and stained by 0.5% AgNO3. The morphological structure was observed and photographed by stereomicroscope to detect the recellularization level. Results The ECs of the bioprosthetic valve were notonly removed completely, but also the collagen fiber and elastic fibers were reserved. The ECs differentiating from MSCs were successfully implanted on the HBS, whose recellularization levels on 7th, 14th and 20th day were 73%, 85%, and 92% respectively. Conclusion AgNO3 staining technique is effective, convenient, and economic in evaluating the recellularization level of BVS. It is an effective method in morphological observation for fabricating tissueengineered heart valve in vitro.
ObjectiveTo analyze the reason and prevention of late bioprosthetic heart valve thrombosis (LBVT). MethodsBioprosthetic heart valves were implanted in 580 patients between January 2001 and July 2013 in Changhai Hospital, and only found one case of LBVT (0.2%). Reoperation was performed for a 67-year-old male patient 3 years after bioprosthetic aortic valve replacement due to severe aortic valve stenosis. Retrospectively analyzed the clinical data and reviewed the literature between January 1989 and December 2013 in Pubmed. ResultsNo risk factor for thrombosis was revealed in this patient. Pathology revealed valve thrombosis and collagen and elastic fibers fragmentation and disruption in valve leaflets. In literature review, 20 articles and 47 cases were brought in. The morbidity of LBVT was 0.2%-1.0%. At least 18 patients had high risk factors, and 15 of the 18 patients discontinued anticoagulation after 3 months. However, at least 10 patients had no high risk factors. Forty-four of the 47 patients received stented porcine valve replacement, only one patient received stented bovine pericardial valve replacement. ConclusionsLBVT is a rare but serious complication after bioprosthetic valve replacement, the causes of which include the feature of the patients and the bioprosthetic valves. Bovine pericardial valves could be superior to porcine valves in preventing LBVT. Postoperative long-time aspirin therapy is recommended for patients without high risk factors. Patients with any high risk factors should prolong anticoagulation.