【Abstract】 Objective To search for a feasibil ity of repairing full-thickness cutaneous deficiency with tissueengineered skin substitute composited by human epidermal stem cells and fibroblasts in fibrin frame. Methods Epidermal stem cells and fibroblasts were harvested from human epidermis and dermis by trypsin digestion. Cells were cultured and subcultured in non-serum medium. Epidermal stem cells (5×104/mL) and dermal fibroblasts (1×104/mL) in 0.5 mL medium were coagulated in 0.5 mL fibrin frame to construct tissue engineered skin substitute. The tissue engineered skin substitute was grafted onto full-thickness cutaneous deficiency of nude mice. Forty-five male mice, 4-5 week old, weighted 20 g on average, were randomly divided into 5 groups. Oil yarn (group C), fibrin frame membrane without cell inoculation (group F), composite skin substitute with epidermal stem cells (group S) and composite skin substitute with fibroblasts (group Fb) were used as controls, while tissue engineered skin substitute (group T) was experimental group. The wounds were observed 1, 3, 6, 8 weeks after surgery. Samples were harvested 3, 6, 8 weeks after surgery, and were examined by means of histology、immunohistochemistryand scanning electron microscopy (SEM). Results Four weeks after cell culture, there were some round cells in the culture capsule of epidemic cells, and some fusiform cells in the culture capsule of fibroblast. Six days after cells were cultured in the BrdU culture medium, there were some BrdU positive cells appeared. There were some CK19 positive cells and Nestin positive cells appeared in the chaff of group T before transplanting. The new formed skin of group T grew faster and had less scar than other groups. Six weeks after surgery, the average thickness of new formed skin was (0.460 ± 0.049) mm in group C, (0.480 ± 0.055) mm in group F, (0.540 ± 0.043) mm in group S, (0.510 ± 0.032) mm in group Fb, (0.660 ± 0.047) mm in group T. The thickness of new formed skin in group T was thicker than other groups (P lt; 0.05). By histology and SEM observation, 3, 6, 8weeks after surgery, the new formed cuticular layer, fibroblast and blood vessels in the group T were more than those in theother groups. The al ignment of blood vessels and collagen fibers in group T were much regular than those in the other groups. Three weeks after surgery, the new formed skin of group T had a continuous color zone of positive collagen Ⅳ staining, while no continuous color zone was found in the other groups. Six weeks after surgery, CK14 positive cells appeared in the new formed skin of group T, while no positive cell was found in the other groups. Conclusion Tissue engineered skin substitute which is composited with epidermal stem cells and fibroblasts in fibrin frame has potential prospects in appl ication of repairing fullthickness cutaneous deficiency with advantage of faster wound heal ing.
Objective To investigate the impact of sarcopenia on effectiveness of lumbar decompression surgery in patients with lumbar spinal stenosis. Methods The clinical data of 50 patients with lumbar spinal stenosis who met the selection criteria between August 2017 and December 2020 were retrospectively analyzed. According to the diagnostic criteria of the European Working Group on Sarcopenia in Older People (EWGSOP), based on the calculation of the skeletal muscle index (SMI) at the L3 level, SMI<45.4 cm2/m2 (men) and SMI<34.4 cm2/m2 (women) were used as the diagnostic threshold, the patients were divided into sarcopenia group (25 cases) and non-sarcopenia group (25 cases). There was no significant difference in gender, age, disease duration, level of lumbar spinal stenosis, surgical fusion level, and comorbidity between the two groups (P>0.05); the body mass index in sarcopenia group was significantly lower than that in non-sarcopenia group (t=−3.198, P=0.002). Clinical data of the two groups were recorded and compared, including operation time, intraoperative blood loss, postoperative drainage volume, hospitalization stay, and complications. The visual analogue scale (VAS) scores of low back pain and sciatica and Oswestry disability index (ODI) scores were recorded preoperatively and at last follow-up. The effectiveness was evaluated according to modified MacNab standard. Results There was no significant difference between the two groups in terms of operation time, intraoperative blood loss, and postoperative drainage volume (P>0.05). However, the hospitalization stay in sarcopenia group was significantly longer than that in non-sarcopenia group (t=2.105, P=0.044). The patients were followed up 7-36 months (mean, 29.7 months). In sarcopenia group, 1 case of dural tear and cerebrospinal fluid leakage occurred during operation, as well as 1 case of internal fixator loosening during follow-up; 1 case of incision exudation and poor healing occurred in each of the two groups, and no adjacent segment degeneration and deep vein thrombosis of lower extremity occurred in the two groups during follow-up. There was no significant difference in the incidence of complications (12% vs. 4%) between the two groups (χ2=1.333, P=0.513). VAS scores in low back pain and sciatica as well as ODI scores in two groups significantly improved when compared with preoperative results at last follow-up (P<0.05). The differences of VAS scores in low back pain and ODI scores before and after operation in sarcopenia group were significantly lower than that in non-sarcopenia group (P<0.05). However, there was no significant difference of that in VAS scores of sciatica between the two groups (t=−1.494, P=0.144). According to the modified MacNab standard, the excellent and good rate of the sarcopenia group was 92%, and that of the non-sarcopenia group was 96%, showing no significant difference between the two groups (χ2=1.201, P=0.753). ConclusionPatients with sarcopenia and lumbar spinal stenosis may have longer postoperative recovery time, and the effectiveness is worse than that of non-sarcopenic patients. Therefore, for elderly patients with lumbar spine disease, it is suggested to improve preoperative assessment of sarcopenia, which can help to identify patients with sarcopenia at risk of poor surgical prognosis in advance, so as to provide rehabilitation guidance and nutritional intervention in the perioperative period.