Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects.

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.

Three dimensional nanofibrous and compressible poly(L-lactic acid) bone grafts loaded with platelet-rich plasma.

In this study, nanofibrous matrices of poly(L-lactic acid)-hydroxyapatite (PLLA-HAp) were successfully fabricated by three-dimensional (3D) electrospinning for use in the treatment of irregular bone damages. Compressibility analysis showed that 3D nanofibrous grafts occupied at least 2-fold more volume than their 2D form and they can easily take shape of the defect zone with irregular geometry. Moreover, the compression moduli of the PLLA and PLLA-HAp grafts were calculated as 8.0 ± 3.0 kPa and 11.8 ± 3.9 kPa, respectively, while the strain values of the same samples at the maximum load of 600 kPa were 164 ± 28% and 130 ± 20%, respectively. Treatment of the grafts with aqueous sodium hydroxide solution increased the surface roughness and thus the alloplastic graft materials (PLLA-HAp/M) protecting the fiber morphology were produced successfully. Then, platelet-rich plasma (PRP) was loaded into the surface modified grafts and activated with 10% calcium chloride. The efficiency of the activation was evaluated with flow cytometry and it was found that after activation the percentages of CD62 (P-selectin) and CD41/61 (glycoprotein IIb/IIIa) proteins increased approximately 4-fold. Surface hydrophilicity and biological activity of the PLLA-HAp grafts were enhanced by fibrin coating after PRP activation. Thein vitrocell culture studies which were carried out by using mouse pre-osteoblasts (MC3T3-E1) showed that graft materials supported by PRP increased cellular proliferation and osteogenic differentiation significantly. Thein vivoresults demonstrated that compared with bare PLLA-HAp/M grafts, the PRP loaded grafts (PRP-PLLA-HAp/M) induced significantly greater bone formation based on computed tomography, histological and immunohistochemical analyses. Our findings suggest that 3D PLLA nanofibrous matrices can be used as a graft material for irregular bone defects especially when combined with PRP as an osteogenic induction agent.