Objective To introduce an injectable andin situ gelling gelatin hydrogel, and to explore the possibility as a carrier for demineralized bone matrix (DBM) powder delivery. Methods First, thiolated gelatin was prepared and the thiol content was determined by Ellman method, and then the injectable andin situ gelling gelatin hydrogel (Gel) was formed by crosslinking of the thiolated gelatin and poly (ethylene oxide) diacrylate and the gelation time was determined by inverted method. Finally, the DBM-Gel composite was prepared by mixing Gel and DBM powder. The cytotoxicity was tested by live/dead staining and Alamar blue assay of the encapsulated cells in the DBM-Gel. Forin vitro cell induction, C2C12 cells were firstly incubated onto the surface of the DBM and then the composite was prepared. The experiment included two groups: DBM-Gel and DBM. The alkaline phosphatase (ALP) activity was determined at 1, 3, 5,and 7 days after culture.In vivo osteoinductivity was evaluated using ectopic bone formation model of nude rats. Histological observation and the ALP activity was measured in DBM-Gel and DBM groups at 4 weeks after implantation. Results The thiol content in the thiolated gelatin was (0.51±0.03) mmol/g determined by Ellman method. The gelation time of the hydrogel was (6±1) minutes. DBM powder can be mixed with the hydrogel and injected into the implantation site within the gelation time. The cells in the DBM-Gel exhibited spreading morphology and connected each other in part with increasing culture time. The viability of the cells was 95.4%±1.9%, 97.3%±1.3%, and 96.1%±1.6% at 1, 3, and 7 days after culture, respectively. The relative proliferation was 1.0±0.0, 1.1±0.1, 1.5±0.1, and 1.6±0.1 at 1, 3, 5, and 7 days after culture respectively.In vitro induction showed that the ALP activity of the DBM-Gel group was similar to that of the DBM group, showing no significant difference (P>0.05). With increasing culture time, the ALP activities in both groups increased gradually and the activity at 5 and 7 days was significantly higher than that at 1 and 3 days (P<0.05), while there was no significant difference between at 1 and 3 days, and between 5 and 7 days (P>0.05). At 4 weeks after implantationin vivo, new bone and cartilage were observed, but no bone marrow formation in DBM-Gel group; in DBM group, new bone, new cartilage, and bone marrow formation were observed. The histological osteoinduction scores of DBM-Gel and DBM groups were 4.0 and 4.5, respectively. The ALP activities of DBM-Gel and DBM groups were respectively (119.4±22.7) and (146.7±13.0) μmol/mg protein/min, showing no significant difference (t=–2.085,P=0.082). Conclusion The injectable andin situ gelling gelatin hydrogel for delivery of DBM is feasible.
Transcatheter aortic valve replacement (TAVR) is a minimally invasive approach to treat symptomatic severe aortic stenosis with surgical taboos or high risk. With the update of the guidelines, the indication of TAVR has been extended to the intermediate-risk aortic stenosis population, and even has a tendency to further expand to the low-risk population. This review highlights the research progress and new evidence of TAVR in respects of patient selection, valve and approach selection, ethnic differences, and surgical complications such as perivalvular leakage, cardiac conduction block, vascular complications, stroke, acute kidney injury, and coronary artery occlusion.
ObjectiveTo analyze the clinical efficacy of right minithoracotomy approach in the treatment of patients with regurgitation after left-sided valve surgery (LSVS).MethodsThe clinical data of 77 patients who suffered tricuspid regurgitation (TR) after LSVS and received surgical treatment in the Heart Center of Henan Provincial People's Hospital from 2012 to 2019 were selected. According to the operation method, the patients were divided into a right minithoracotomy group (n=32), including 13 (40.6%) males, aged 57.3±5.3 years and a median sternotomy group (n=45), including 17 (37.8%) males, aged 55.7±6.6 years. Preoperative and postoperative clinical data of the two groups were compared and analyzed.ResultsThere was no significant difference in preoperative data between the two groups. There were 24 patients of tricuspid valvuloplasty (TVP) and 8 patients of tricuspid valve replacement (TVR) in the right minithoracotomy group. There were 29 patients of TVP and 16 patients of TVR in the median sternotomy group. The operation time, postoperative hospitalization time, intubation time and ICU stay time of the right minithoracotomy group were shorter than those of the median sternotomy group (P<0.001). The operative bleeding, postoperative drainage in 24 hours, postoperative blood transfusion rate and incision poor healing of the right minithoracotomy group were significantly decreased compared with those of the median sternotomy group (P<0.05). The extracorporeal circulation time between the two groups was not significantly different (P=0.382). The postoperative complications and mortality of the righ minithoracotomy group were significantly lower than those of the median sternotomy group (P<0.05).ConclusionThe procedure of right minithoracotomy access can reduce perioperative morbidity and mortality compared with the median sternotomy, and results in satisfied clinical efficacy.
