Myogenic differentiation of human myoblasts and Mesenchymal stromal cells under GDF11 on NPoly-ɛ-caprolactone-collagen I-Polyethylene-nanofibers.

BACKGROUND: For the purpose of skeletal muscle engineering, primary myoblasts (Mb) and adipogenic mesenchymal stem cells (ADSC) can be co-cultured and myogenically differentiated. Electrospun composite nanofiber scaffolds represent suitable matrices for tissue engineering of skeletal muscle, combining both biocompatibility and stability Although growth differentiation factor 11 (GDF11) has been proposed as a rejuvenating circulating factor, restoring skeletal muscle function in aging mice, some studies have also described a harming effect of GDF11. Therefore, the aim of the study was to analyze the effect of GDF11 on co-cultures of Mb and ADSC on poly-ε-caprolactone (PCL)-collagen I-polyethylene oxide (PEO)-nanofibers. RESULTS: Human Mb were co-cultured with ADSC two-dimensionally (2D) as monolayers or three-dimensionally (3D) on aligned PCL-collagen I-PEO-nanofibers. Differentiation media were either serum-free with or without GDF11, or serum containing as in a conventional differentiation medium. Cell viability was higher after conventional myogenic differentiation compared to serum-free and serum-free + GDF11 differentiation as was creatine kinase activity. Immunofluorescence staining showed myosine heavy chain expression in all groups after 28 days of differentiation without any clear evidence of more or less pronounced expression in either group. Gene expression of myosine heavy chain (MYH2) increased after serum-free + GDF11 stimulation compared to serum-free stimulation alone. CONCLUSIONS: This is the first study analyzing the effect of GDF11 on myogenic differentiation of Mb and ADSC co-cultures under serum-free conditions. The results of this study show that PCL-collagen I-PEO-nanofibers represent a suitable matrix for 3D myogenic differentiation of Mb and ADSC. In this context, GDF11 seems to promote myogenic differentiation of Mb and ADSC co-cultures compared to serum-free differentiation without any evidence of a harming effect.

Schwann Cells Promote Myogenic Differentiation of Myoblasts and Adipogenic Mesenchymal Stromal Cells on Poly-ɛ-Caprolactone-Collagen I-Nanofibers.

For the purpose of skeletal muscle tissue engineering, different cell types have been investigated regarding their myogenic differentiation potential, including co-cultured myoblasts and adipogenic mesenchymal stromal cells (Mb/ADSC). As neural cells enhance synaptic junction formation, the aim of this study was to co-culture Schwann cells (SCs) with Mb/ADSC on biocompatible electrospun aligned poly-ε-polycaprolacton (PCL)-collagen I-nanofibers. It was hypothesized that SCs, as part of the peripheral nervous system, promote the myogenic differentiation of Mb/ADSC co-cultures. Mb/ADSC were compared to Mb/ADSC/SC regarding their capacity for myogenic differentiation via immunofluorescent staining and gene expression of myogenic markers. Mb/ADSC/SC showed more myotubes after 28 days of differentiation (p ≤ 0.05). After 28 days of differentiation on electrospun aligned PCL-collagen I-nanofibers, gene expression of myosin heavy chains (MYH2) and myogenin (MYOG) was upregulated in Mb/ADSC/SC compared to Mb/ADSC (p ≤ 0.01 and p ≤ 0.05, respectively). Immunofluorescent staining for MHC showed highly aligned multinucleated cells as possible myotube formation in Mb/ADSC/SC. In conclusion, SCs promote myogenic differentiation of Mb/ADSC. The co-culture of primary Mb/ADSC/SC on PCL-collagen I-nanofibers serves as a physiological model for skeletal muscle tissue engineering, applicable to future clinical applications.

A Novel Knotless Barbed Suture Technique for Traumatic Thoracolumbar Fracture in Posterior Surgery.

BACKGROUND: Surgical wound closure directly influences spinal surgical efficiency and several postoperative complications. The traditional suture technique is time-consuming and associated with greater rates of complications. Bidirectional absorbable barbed sutures seem to compensate for some of the limitations of traditional suture; however, they rarely are reported in spinal surgery. We designed a novel suture technique for use in thoracolumbar spinal surgery. METHODS: The data of 189 patients with traumatic thoracolumbar fractures were analyzed between bidirectional barbed suture closure and traditional interrupted suture closure. Data of operative time, wound closure time, length of incision, intraoperative blood loss, complications of wound dehiscence and postoperative hematoma, cost, and neurologic status were collected. RESULTS: No significant differences were observed in the baseline demographics of included patients. Compared with the traditional suturing group, the barbed sutures decreased the mean operative time (P = 0.037), suture time (P < 0.01), and mean suturing time (P < 0.01) significantly, although no statistically significant differences were found in blood loss (P = 0.724) and neurologic functional scores (preoperative: P = 0.901; 3 months after surgery: P = 0.208; final follow-up assessments: P = 0.163), and no statistically significant differences were found in rates of postoperative infection, hematoma, and wound dehiscence. CONCLUSIONS: Our findings suggest that the novel knotless barbed suture has comparable strength to traditional sutures, with the advantage of less suturing time. It is an efficient, safe technique, and alternative choice for patients with thoracolumbar fracture after posterior surgery.

Celastrol reduces IL-1ß induced matrix catabolism, oxidative stress and inflammation in human nucleus pulposus cells and attenuates rat intervertebral disc degeneration in vivo.

Celastrol has been reported to exert therapeutic potential on pro-inflammatory diseases including asthma, Crohn's disease, arthritis and neurodegenerative disorders via inhibiting NF-κB pathway. While the effect of celastrol on intervertebral disc degeneration (IDD), which is also a pro-inflammatory disease, remains unknown. In this study, we evaluated the effect of celastrol on IDD in IL-1ß treated human nucleus pulposus cells in vitro as well as in puncture induced rat IDD model in vivo. Our results showed that celastrol reduced the expression of catabolic genes (MMP-3, 9, 13, ADAMTS-4, 5), oxidative stress factors (COX-2, iNOS) and pro-inflammatory factors (IL-6, TNF-a) induced by IL-1ß in nucleus pulposus cells, also phosphorylation of IκBα and p65 were attenuated by celastrol, indicating NF-κB pathway was inhibited by celastrol in nucleus pulposus cells. In vivo study showed that celastrol treated rats had stronger T2-weighted signal than vehicle-treated rats at 2 weeks and 6 weeks' time point, suggesting celastrol could attenuate intervertebral disc degeneration in vivo. Together, our study demonstrates that celastrol could reduce IL-1ß induced matrix catabolism, oxidative stress and inflammation in human nucleus pulposus cells and attenuates rat intervertebral disc degeneration in vivo, which shows its potential to be a therapeutic drug for IDD.

Risk factors of kyphosis recurrence after implant removal in thoracolumbar burst fractures following posterior short-segment fixation.

PURPOSE: Our aim was to evaluate the results of short-segment pedicle instrumentation with screw insertion in the fracture level and find factors predicting kyphosis recurrence in thoracolumbar burst fractures. METHODS: We retrospectively analysed 122 patients with thoracolumbar burst fracture who were divided into two groups: kyphosis recurrence and no kyphosis recurrence. Pre-operative radiographic data comprising Cobb angle (CA), regional angle, anterior vertebra height (AVH), upper intervertebral angle, vertebral wedge angle (VWA), pre-anteroposterior A/P approach, superior endplate fracture, load-sharing classification (LSC) score and clinical data including age, visual analogue scale (VAS) score, thoracolumbar injury classification and severity score were compared between groups. T test, Pearson's chi-square and multivariate logistic regression were calculated for variables. RESULTS: CA, VWA and AVH were significantly corrected after surgery. CA changed from 23.7 to 3.0 (p <0.001), VWA from 38.7 to 9.6 (p <0.001) and AVH from 48.8 % to 91.2 % (p <0.001). These parameters were well maintained during the follow-up period with a mild, tolerant loss of correction. Neurological function and pain were significantly improved without deterioration. Age, pre-A/P and pre-AVH < 50 % influenced kyphosis recurrence (p = 0.032, 0.026, 0.011, respectively). CONCLUSIONS: Short-segment pedicle instrumentation including the fractured vertebra was effective in treating thoracolumbar burst fractures. The loss of correction at follow-up after implant removal was associated with age, A/P ratio and anterior vertebral height < 50 %.