Novel biodegradable three-dimensional macroporous scaffold using aligned electrospun nanofibrous yarns for bone tissue engineering.

This study aimed to develop a practical three-dimensional (3D) macroporous scaffold from aligned electrospun nanofibrous yarns for bone tissue engineering. A novel 3D unwoven macroporous nanofibrous (MNF) scaffold was manufactured with electrospun poly(L-lactic acid) and polycaprolactone (w/w 9:1) nanofibers through sequential yarns manufacture and honeycombing process at 65°C. The efficacy of 3D MNF scaffold for bone formation were evaluated using human embryonic stem cell-derived mesenchymal stem cells (hESC-MSCs) differentiation model and rabbit tibia bone defect model. In vitro, more cell proliferation and cell ingrowth were observed in 3D MNF scaffold. Moreover, calcium deposit was obviously detected in vitro differentiation of hESC-MSCs. In vivo, histology and X-ray showed that 3D MNF scaffold treated bone defect had fine 3D bony tissue formation around the scaffold as well as inside the scaffold at 3 weeks and 6 weeks. This study demonstrated that 3D MNF scaffold provides a structural support for hESC-MSCs growth and guides bone formation suggesting that this novel strategy successfully makes use of electrospun fibers for bone tissue engineering, which may help realize the clinical translation of electrospun nanofibers for regenerative medicine in future.

Electrospun nanofibrous matrix improves the regeneration of dense cortical bone.

Numerous in vitro studies have indicated the potential of using electrospun nanofibrous scaffolds for tissue regeneration. However, few reports have demonstrated their utility in real tissue repair models. The present investigation tested the hypothesis that electrospun poly-L-lactic acid (PLLA) nanofibrous membrane leads to dense cortical bone regeneration and improves the efficacy of currently-used collagenous guided bone regeneration (GBR) membrane. In vitro, the function of bone marrow-derived mesenchymal stem cells (BMSCs) on nanofibrous scaffolds was evaluated. In an in vivo experiment, large bony defects were created in rabbit tibia and treated with a nanofiber-reinforced bilayer membrane, nanofibrous membrane, or collagenous membrane alone. Three and six weeks after operation, bone defect healing was assessed radiologically and histologically. In vitro differentiation studies showed that BMSCs had much higher expression of Runx2 and collagen type I, alpha 1 mRNAs, when cultured on nanofibrous scaffolds. The radiographic and histological data both showed that the group treated with bilayer membrane had more bony tissue formation at 3 weeks. Moreover, at 6 weeks, only the bilayer membrane-treated bone defects displayed better regeneration of cortical bone tissue, whereas in the other groups the defects were filled with spongy bone-like tissue. The results demonstrated that electrospun nanofibrous membrane improves the regeneration of cortical bone, suggesting that this type of membrane can be combined with current collagenous GBR membrane to improve guided bone regeneration technology.

Mesenchymal stem cell seeded knitted silk sling for the treatment of stress urinary incontinence.

Stress urinary incontinence remains a worldwide problem affecting patients of all ages. Implantation of suburethral sling is the cornerstone treatment. Current slings have inherent disadvantages. This study aims to develop a tissue engineered sling with bone marrow derived mesenchymal stem cell seeded degradable silk scaffold. The mesenchymal stem cells were obtained from Sprague-Dawley rats and were characterized in vitro. Layered cell sheets were formed after two weeks of culture and were labeled with carboxyfluorescein diacetate. Forty female rats were divided into four groups: Group A (n=5) had sham operation; other three groups underwent bilateral proximal sciatic nerve transection and were confirmed with stress urinary incontinence by the leak-point pressure measurement at 4 weeks after operation. Then, Group B (n=5) had no sling placed; Group C (n=15) was treated with a silk sling; and Group D (n=15) was treated with the tissue engineered sling. Histology and the leak-point pressure measurements were done at 4 and 12 weeks after the sling implantation while collagen content and mechanical testing were done at 12 weeks. The results showed that Group B had a significantly lower leak-point pressure (24.0+/-4.2 cmH(2)O) at 4 weeks (P<0.05), while Group C (38.0+/-3.3 cmH(2)O) and Group D (36.3+/-3.1 cmH(2)O) almost reached to the normal level shown by Group A (41.6+/-3.8 cmH(2)O) (p>0.05). At 12 weeks, tissue engineered sling of group D has higher collagen content (70.84+/-14.49 microg/mg) and failure force (2.436+/-0.192 N) when compared those of Group C (38.94+/-7.05 microg/mg and 1.521+/-0.087 N) (p<0.05). Both the silk sling and tissue engineered sling showed convincing functional effects for the treatment of stress urinary incontinence in a rat model. And the better ligament-like tissue formation in the tissue engineered sling suggested potential long-term function.