Preparation and evaluation of a silk fibroin-polycaprolactone biodegradable biomimetic tracheal scaffold.

In tracheal tissue engineering, the construction of tracheal scaffolds with adequate biodegradable mechanical capacity and biological functions that mimic the structure of a natural trachea is challenging. To explore the feasibility of preparing biomimetic degradable scaffolds with C-type cartilage rings and an inner tracheal wall of polycaprolactone and silk fibroin. A mold was made according to the diameter of a rabbit trachea, and a silk fibroin tube and polycaprolactone ring attached to the tube were obtained by solution casting. The ring was fixed to the tube at a specific spacing using electrostatic spinning technology to construct a biomimetic tracheal scaffold; its porous structure was observed by scanning electron microscopy, its degradation properties were determined by in vitro enzymatic hydrolysis and its mechanical properties were obtained by pressure testing. The composite scaffold was transplanted subcutaneously into a rabbit model, and the scaffold was taken at 1, 2, and 4 weeks after surgery for sectioning to observe pre-vascularization. The Medical Ethics Committee of Guangdong Provincial People's Hospital approved the study. The general view of the biomimetic scaffold: the polycaprolactone ring was fixed firmly on the outer wall of the silk fibroin tube; the two corresponded in size, and they fitted closely. The surface of the polycaprolactone ring was smooth and dense, while the surface of the silk fibroin tube could be seen as a uniform porous structure. Scanning electron microscopy showed that the surface and profile of the fibroin tube had a uniform pore size and distribution. The pores were connected to form a network. In vitro, enzymatic hydrolysis experiments confirmed that the fibroin was degraded easily, with most being degraded at the end of week 1. The degradation slowed at 2, 3, and 4 weeks, while the degradation of polycaprolactone was extremely slow. A compression test showed that the compressive resistance of the silk fibroin-polycaprolactone biomimetic scaffolds was much better than that of the rabbit trachea at close thickness. In the tissue staining experiments, as the material degraded, fibrous tissues and blood vessels grew to replace the material, allowing the scaffold to obtain a blood supply and better mechanical properties. A quantitative analysis of CD31 showed that the results for the vascularization of the scaffold were better at 4 weeks than at 2 weeks following subcutaneous grafting (P < .05). The results confirmed that it is feasible to prepare porous, degradable silk fibroin-polycaprolactone biomimetic scaffolds with good mechanical properties and epithelial biological functions by mold casting.

The implications of an integrated management model of prenatal diagnosis/postnatal treatment for premature infants with critical congenital heart disease-a case-control study.

Background: The high death rate and medical costs of critical congenital heart disease (CCHD) in preterm infants has resulted in significant burdens on both countries and individuals. It is unclear how this affects the mortality of the integrated management model of prenatal diagnosis/postnatal treatment. This study explored the effects of the delivery classification scale for fetal heart and postnatal infants' CCHD on prenatal and postnatal integrated treatment strategies to improve the effectiveness of disease management in CCHD. Methods: This study was a case-control study, which retrospectively analyzed the clinical data of 79 preterm infants (<37 weeks) who underwent prenatal diagnosis and postpartum treatment in Guangdong Provincial People' s Hospital (China) from June 2017 to June 2019. According to the diagnostic and exclusion criteria, the subjects were divided into prenatal and postpartum diagnostic groups. The clinical characteristics and survival outcomes of patients were collected and compared. The delivery classification scale was used for risk stratification and patient management. Results: Among the 79 patients included in this study, 48 (60.76%) were diagnosed prenatally, and 31 (39.24%) were diagnosed postpartum. The prenatal diagnosis group was born slightly earlier during the gestation period [35.00 (33.29-35.86) vs. 35.57 (34.14-36.71) weeks, P<0.05], and their mothers were older (33.23±5.22 vs. 30.43±6.37 years, P<0.05). The difference in the admission age between the groups was statistically significant [0 (0-5.5) vs. 7 (5-16) days, P<0.001]. The median survival time of the prenatal diagnosis group was higher than the postnatal diagnosis group [48 months (95% CI: 40.78-57.29) vs. 39 months (95% CI: 34.41-44.32), P<0.05]. The 3-year survival rates of the classes I, II, and III were 92.31% (12/13), 59.09% (13/22), and 38.46% (5/13), respectively. The survival of class I as denoted in the delivery classification scale was better than classes II or III (class I vs. II, P<0.05; class I vs. III, P<0.05). Unexpectedly, the hospitalisation costs were lower and total in-hospital days were shorter in the postnatal diagnosis group. Conclusions: The results indicated that the integrated management of a prenatal diagnosis/postnatal treatment approach in premature infants may be effective. Furthermore, the delivery classification scale has a particular prognostic value for CCHD. The authors anticipate that their management model will be able to contribute to the shift from a reactive monodisciplinary system to a proactive, multidisciplinary and dynamic management paradigm in premature infants with CCHD in the near future.

The Application of a Bone Marrow Mesenchymal Stem Cell Membrane in the Vascularization of a Decellularized Tracheal Scaffold.

Airway stenosis is a common problem in the neonatal intensive care unit (NICU) and pediatric intensive care unit (PICU). A tissue-engineered trachea is a new therapeutic method and a research hotspot. Successful vascularization is the key to the application of a tissue-engineered trachea. However, successful vascularization studies lack a complete description. In this study, it was assumed that rabbit bone marrow mesenchymal stem cells were obtained and induced by ascorbic acid to detect the tissue structure, ultrastructure, and gene expression of the extracellular matrix. A vascular endothelial cell culture medium was added in vitro to induce the vascularization of the stem cell sheet (SCS), and the immunohistochemistry and gene expression of vascular endothelial cell markers were detected. At the same time, vascular growth-related factors were added and detected during SCS construction. After the SCS and decellularized tracheal (DT) were constructed, a tetrandrine allograft was performed to observe its vascularization potential. We established the architecture and identified rabbit bone marrow mesenchymal stem cell membranes by 14 days of ascorbic acid, studied the role of a vascularized membrane in inducing bone marrow mesenchymal stem cells by in vitro ascorbic acid, and assessed the role of combining the stem cell membranes and noncellular tracheal scaffolds in vivo. Fourteen experiments confirmed that cell membranes promote angiogenesis at gene level. The results of 21-day in vitro experiments showed that the composite tissue-engineered trachea had strong angiogenesis. In vivo experiments show that a composite tissue-engineered trachea has strong potential for angiogenesis. It promotes the understanding of diseases of airway stenosis and tissue-engineered tracheal regeneration in newborns and small infants.

Intra-Spinal Bone Marrow Mononuclear Cells Transplantation Inhibits the Expression of Nuclear Factor-kappaB in Acute Transection Spinal Cord Injury in Rats

OBJECTIVE: To assess the effect of bone marrow mononuclear cells (BMMNCs) transplantation in the expression of nuclear factor-kappaB (NF-kappaB) in spinal cord injury (SCI) in rats. METHODS: BMMNCs were isolated from tibia and femur by a density gradient centrifugation. After establishment of acute transection SCI, rats were divided into experiment (BMMNCs), experiment control (0.1 M PBS infused) and sham surgery groups (laminectomy without any SCI). Locomotor function was assessed weekly for 5 weeks post-injury using BBB locomotor score and urinary bladder function daily for 4 weeks post-injury. Activity of NF-kappaB in spinal cord was assessed by immunohistochemistry and reverse transcriptase polymerase chain reaction. RESULTS: At each time point post-injury, sham surgery group had significantly higher Basso, Beattie, Bresnahan locomotor and urinary bladder function scores than experiment and experiment control group (p<0.05). At subsequent time interval there were gradual improvement in both experiment and experiment control group, but experiment group had higher score in comparison to experiment control group (p<0.05). Comparisons were also made for expression of activated NF-kappaB positive cells and level of NF-kappaB messenger RNA in spinal cord at various time points between the groups. Activated NF-kappaB immunoreactivity and level of NF-kappaB mRNA expression were significantly higher in control group in comparison to experiment and sham surgery group (p<0.05). CONCLUSION: BMMNCs transplantation attenuates the expression of NF-kappaB in injured spinal cord tissue and thus helps in recovery of neurological function in rat models with SCI.