Tripterine Inhibits Proliferation and Promotes Apoptosis of Keloid Fibroblasts by Targeting ROS/JNK Signaling.

Keloids are benign skin tumors characterized by excessive fibroblast proliferation and collagen deposition. The current treatment of keloids with hormone drug injection, surgical excision, radiotherapy, physical compression, laser therapy, cryotherapy often have unsatisfactory outcomes. The phytochemical compounds have shown great potential in treating keloids. Tripterine, a natural triterpene derived from the traditional Chinese medicine Thunder God Vine (Tripterygium wilfordii), was previously reported to exhibit an anti-scarring bioactivity in mouse embryonic fibroblast NIH/3T3 cells. Accordingly, our study was dedicated to explore its role in regulating the pathological phenotypes of keloid fibroblasts. Human keloid fibroblasts were treated with tripterine (0-10 µM) for 24 hours. Cell viability, proliferation, migration, apoptosis, and extracellular matrix (ECM) deposition were determined by CCK-8, EdU, wound healing, Transwell, flow cytometry, western blotting, and RT-qPCR assays. The effects of tripterine treatment on reactive oxygen species (ROS) generation and JNK activation in keloid fibroblasts were assessed by DCFH-DA staining and western blotting analysis. Tripterine at the concentrations higher than 4 µM attenuated the viability of human keloid fibroblasts in a dose-dependent manner. Treatment with tripterine (4, 6, and 8 µM) dose-dependently inhibited cell proliferation and migration, promoted cell apoptosis, reduced α-SMA, Col1, and Fn expression, induced ROS production, and enhanced JNK phosphorylation in keloid fibroblasts. Collectively, tripterine ameliorates the pathological characteristics of keloid fibroblasts that are associated with keloidformation and growth by inducing ROS generation and activating JNK signalingpathway.

Neural tissue-engineered prevascularization in vivo enhances peripheral neuroregeneration via rapid vascular inosculation.

Neural tissue engineering techniques typically face a significant challenge, simulating complex natural vascular systems that hinder the clinical application of tissue-engineered nerve grafts (TENGs). Here, we report a subcutaneously pre-vascularized TENG consisting of a vascular endothelial growth factor-induced host vascular network, chitosan nerve conduit, and inserted silk fibroin fibers. Contrast agent perfusion, tissue clearing, microCT scan, and blood vessel 3D reconstruction were carried out continuously to prove whether the regenerated blood vessels were functional. Moreover, histological and electrophysiological evaluations were also applied to investigate the efficacy of repairing peripheral nerve defects with pre-vascularized TENG. Rapid vascular inosculation of TENG pre-vascularized blood vessels with the host vascular system was observed at 4 â€‹d bridging the 10 â€‹mm sciatic nerve defect in rats. Transplantation of pre-vascularized TENG in vivo suppressed proliferation of vascular endothelial cells (VECs) while promoting their migration within 14 â€‹d post bridging surgery. More importantly, the early vascularization of TENG drives axonal regrowth by facilitating bidirectional migration of Schwann cells (SCs) and the bands of Büngner formation. This pre-vascularized TENG increased remyelination, promoted recovery of electrophysiological function, and prevented atrophy of the target muscles when observed 12 weeks post neural transplantation. The neural tissue-engineered pre-vascularization technique provides a potential approach to discover an individualized TENG and explore the innovative neural regenerative process.

Skin precursor-derived Schwann cells accelerate in vivo prevascularization of tissue-engineered nerves to promote peripheral nerve regeneration.

Prevascularization strategies have become a hot spot in tissue engineering. As one of the potential candidates for seed cells, skin precursor-derived Schwann cells (SKP-SCs) were endowed with a new role to more efficiently construct prevascularized tissue-engineered peripheral nerves. The silk fibroin scaffolds seeded with SKP-SCs were prevascularized through subcutaneously implantation, which was further assembled with the SKP-SC-containing chitosan conduit. SKP-SCs expressed pro-angiogenic factors in vitro and in vivo. SKP-SCs significantly accelerated the satisfied prevascularization in vivo of silk fibroin scaffolds compared with VEGF. Moreover, the NGF expression revealed that pregenerated blood vessels adapted to the nerve regeneration microenvironment through reeducation. The short-term nerve regeneration of SKP-SCs-prevascularization was obviously superior to that of non-prevascularization. At 12 weeks postinjury, both SKP-SCs-prevascularization and VEGF-prevascularization significantly improved nerve regeneration with a comparable degree. Our figures provide a new enlightenment for the optimization of prevascularization strategies and how to further utilize tissue engineering for better repair.

Glioblastoma genetic drivers dictate the function of tumor-associated macrophages/microglia and responses to CSF1R inhibition.

BACKGROUND: Tumor-associated macrophages/microglia (TAMs) are prominent microenvironment components in human glioblastoma (GBM) that are potential targets for anti-tumor therapy. However, TAM depletion by CSF1R inhibition showed mixed results in clinical trials. We hypothesized that GBM subtype-specific tumor microenvironment (TME) conveys distinct sensitivities to TAM targeting. METHODS: We generated syngeneic PDGFB- and RAS-driven GBM models that resemble proneural-like and mesenchymal-like gliomas, and determined the effect of TAM targeting by CSF1R inhibitor PLX3397 on glioma growth. We also investigated the co-targeting of TAMs and angiogenesis on PLX3397-resistant RAS-driven GBM. Using single-cell transcriptomic profiling, we further explored differences in TME cellular compositions and functions in PDGFB- and RAS-driven gliomas. RESULTS: We found that growth of PDGFB-driven tumors was markedly inhibited by PLX3397. In contrast, depletion of TAMs at the early phase accelerated RAS-driven tumor growth and had no effects on other proneural and mesenchymal GBM models. In addition, PLX3397-resistant RAS-driven tumors did not respond to PI3K signaling inhibition. Single-cell transcriptomic profiling revealed that PDGFB-driven gliomas induced expansion and activation of pro-tumor microglia, whereas TAMs in mesenchymal RAS-driven GBM were enriched in pro-inflammatory and angiogenic signaling. Co-targeting of TAMs and angiogenesis decreased cell proliferation and changed the morphology of RAS-driven gliomas. CONCLUSIONS: Our work identifies functionally distinct TAM subpopulations in the growth of different glioma subtypes. Notably, we uncover a potential responsiveness of resistant mesenchymal-like gliomas to combined anti-angiogenic therapy and CSF1R inhibition. These data highlight the importance of characterization of the microenvironment landscape in order to optimally stratify patients for TAM-targeted therapy.

BMSC-derived extracellular matrix better optimizes the microenvironment to support nerve regeneration.

A favorable microenvironment plays an important role in nerve regeneration. Extracellular matrix (ECM) derived from cultured cells or natural tissues can facilitate nerve regeneration in the presence of various microenvironmental cues, including biochemical, spatial, and biomechanical factors. This study, through proteomics and three-dimensional image analysis, determines that the components and spatial organization of the ECM secreted by bone marrow mesenchymal cells (BMSCs) are more similar to acellular nerves than those of the ECMs derived from Schwann cells (SCs), skin-derived precursor Schwann cells (SKP-SCs), or fibroblasts (FBs). ECM-modified nerve grafts (ECM-NGs) are engineered by co-cultivating BMSCs, SCs, FBs, SKP-SCs with well-designed nerve grafts used to bridge nerve defects. BMSC-ECM-NGs exhibit the most promising nerve repair properties based on the histology, neurophysiology, and behavioral analyses. The regeneration microenvironment formed by the ECM-NGs is also characterized by proteomics, and the advantages of BMSC-ECM-NGs are evidenced by the enhanced expression of factors related to neural regeneration and reduced immune response. Together, these findings indicate that BMSC-derived ECMs create a more superior microenvironment for nerve regeneration than that by the other ECMs and may, therefore, represent a potential alternative for the clinical repair of peripheral nerve defects.

pH-Responsive doxorubicin delivery using shear-thinning biomaterials for localized melanoma treatment.

Injectable shear-thinning biomaterials (STBs) have attracted significant attention because of their efficient and localized delivery of cells as well as various molecules ranging from growth factors to drugs. Recently, electrostatic interaction-based STBs, including gelatin/LAPONITE® nanocomposites, have been developed through a simple assembly process and show outstanding shear-thinning properties and injectability. However, the ability of different compositions of gelatin and LAPONITE® to modulate doxorubicin (DOX) delivery at different pH values to enhance the effectiveness of topical skin cancer treatment is still unclear. Here, we fabricated injectable STBs using gelatin and LAPONITE® to investigate the influence of LAPONITE®/gelatin ratio on mechanical characteristics, capacity for DOX release in response to different pH values, and cytotoxicity toward malignant melanoma. The release profile analysis of various compositions of DOX-loaded STBs under different pH conditions revealed that lower amounts of LAPONITE® (6NC25) led to higher pH-responsiveness capable of achieving a localized, controlled, and sustained release of DOX in an acidic tumor microenvironment. Moreover, we showed that 6NC25 had a lower storage modulus and required lower injection forces compared to those with higher LAPONITE® ratios. Furthermore, DOX delivery analysis in vitro and in vivo demonstrated that DOX-loaded 6NC25 could efficiently target subcutaneous malignant tumors via DOX-induced cell death and growth restriction.

Biodegradable ß-Cyclodextrin Conjugated Gelatin Methacryloyl Microneedle for Delivery of Water-Insoluble Drug.

Transdermal delivery of water-insoluble drugs via hydrogel-based microneedle (MN) arrays is crucial for improving their therapeutic efficacies. However, direct loading of water-insoluble drug into hydrophilic matrices remains challenging. Here, a biodegradable MN array patch that is fabricated from naturally derived polymer conjugates of gelatin methacryloyl and ß-cyclodextrin (GelMA-ß-CD) is reported. When curcumin, an unstable and water-insoluble anticancer drug, is loaded as a model drug, its stability and solubility are improved due to the formation of an inclusion complex. The polymer-drug complex GelMA-ß-CD/CUR can be formulated into MN arrays with sufficient mechanical strength for skin penetration and tunable drug release profile. Anticancer efficacy of released curcumin is observed in three-dimensional B16F10 melanoma models. The GelMA-ß-CD/CUR MN exhibits relatively higher therapeutic efficacy through more localized and deeper penetrated manner compared with a control nontransdermal patch. In vivo studies also verify biocompatibility and degradability of the GelMA-ß-CD MN arrays patch.

Bone marrow-derived neural crest precursors improve nerve defect repair partially through secreted trophic factors.

BACKGROUND: Emerging evidence suggests that neural crest-derived cells (NCCs) present important functions in peripheral nerve regeneration to correct the insufficiency of autogenous Schwann cells. Postmigratory NCCs have been successfully isolated from adult rat bone marrow in our previous work. In this study, we aim to provide neural crest-derived Schwann cell precursors (SCPs) for repair of nerve defects in adult rats, and partially reveal the mechanisms involved in neuroregeneration of cell therapy. METHODS: A clonal cell line of neural crest precursors of rat bone marrow origin (rBM-NCPs) with SCP identity was expanded in adherent monolayer culture to ensure the stable cell viability of NCPs and potentiate the repair of nerve defects after rBM-NCPs implantation based on tissue engineering nerve grafts (TENG). Here the behavioral, morphological, and electrophysiological detection was performed to evaluate the therapy efficacy. We further investigated the treatment with NCP-conditioned medium (NCP-CM) to sensory neurons after exposure to oxygen-glucose-deprivation (OGD) and partially compared the expression of trophic factor genes in rBM-NCPs with that in mesenchymal stem cells of bone marrow origin (rBM-MSCs). RESULTS: It was showed that the constructed TENG with rBM-NCPs loaded into silk fibroin fiber scaffolds/chitosan conduits repaired 10-mm long sciatic nerve defects more efficiently than conduits alone. The axonal regrowth, remyelination promoted the reinnervation of the denervated hind limb muscle and skin and thereby alleviated muscle atrophy and facilitated the rehabilitation of motor and sensory function. Moreover, it was demonstrated that treatment with NCP-CM could restore the cultured primary sensory neurons after OGD through trophic factors including epidermal growth factor (EGF), platelet-derived growth factor alpha (PDGFα), ciliary neurotrophic factor (CNTF), and vascular endothelial growth factor alpha (VEGFα). CONCLUSIONS: In summary, our findings indicated that monolayer-cultured rBM-NCPs cell-based therapy might effectively repair peripheral nerve defects partially through secreted trophic factors, which represented the secretome of rBM-NCPs differing from that of rBM-MSCs.

The Landscape of Gene Expression and Molecular Regulation Following Spinal Cord Hemisection in Rats.

Spinal cord injury (SCI) is a challenging clinical problem worldwide. The cellular state and molecular expression in spinal cord tissue after injury are extremely complex and closely related to functional recovery. However, the spatial and temporal changes of gene expression and regulation in various cell types after SCI are still unclear. Here, we collected the rostral and caudal regions to the lesion at 11 time points over a period of 28 days after rat hemisection SCI. Combining whole-transcriptome sequencing and bioinformatic analysis, we identified differentially expressed genes (DEGs) between spinal cord tissue from injured and sham-operated animals. Significantly altered biological processes were enriched from DEGs in astrocytes, microglia, oligodendrocytes, immune cells, and vascular systems after SCI. We then identified dynamic trends in these processes using the average expression profiles of DEGs. Gene expression and regulatory networks for selected biological processes were also constructed to illustrate the complicate difference between rostral and caudal tissues. Finally, we validated the expressions of some key genes from these networks, including α-synuclein, heme oxygenase 1, bone morphogenetic protein 2, activating transcription factor 3, and leukemia inhibitory factor. Collectively, we provided a comprehensive network of gene expression and regulation to shed light on the molecular characteristics of critical biological processes that occur after SCI, which will broaden the understanding of SCI and facilitate clinical therapeutics for SCI.

A long-term maternal diet intervention is necessary to avoid the obesogenic effect of maternal high-fat diet in the offspring.

Although a pre-pregnancy dietary intervention is believed to be able to prevent offspring obesity, research evidence is absent. We hypothesize that a long period of pre-pregnancy maternal diet transition from a high-fat (HF) diet to a normal-fat (NF) diet effectively prevents offspring obesity, and this preventive effect is independent of maternal body weight change. In our study, female mice were either continued on an NF diet (NF group) or an HF diet (HF group) until weaning, or switched from an HF to an NF for 1 week (H1N group), 5 weeks (H5N group) or 9 weeks (H9N group) before pregnancy. After weaning, the offspring were given the HF diet for 12 weeks to promote obesity. The mothers, regardless of which group, did not display maternal body weight change and glucose intolerance either before pregnancy or after weaning. Compared to the HF group, the H1N and H5N, but not the H9N, offspring developed glucose intolerance earlier, with more severely imbalanced glucose homeostasis. These offspring also displayed hepatocyte degeneration and significant adipocyte hypertrophy associated with higher expression of lipogenesis genes. The molecular mechanistic study showed blunted insulin signaling, overactivated adipocyte Akt signaling and hepatic AMPK signaling with enhanced lipogenesis genes in the H1N and H5N versus the NF offspring. However, maternal H9N diets normalized glucose and lipid metabolism of the offspring via resensitized insulin signaling and normalized Akt and AMPK signaling. In summary, we showed that a long-term maternal diet intervention effectively released the intergenerational obesogenic effect of maternal HF diet independent of maternal weight management.

Transcriptional Repression of p53 by PAX3 Contributes to Gliomagenesis and Differentiation of Glioma Stem Cells.

Although there are available therapies as surgery, chemotherapy and radiation, glioblastoma (GBM) still has been considered as the most common and overwhelming primary tumor of brain. In GBM, the brain glioma stem cells (BGSCs) were identified and played a crucial role in resistance of GBM to conventional therapies described above. PAX3 was previously identified by our group as a diagnostic/prognostic marker and a therapeutic regulator in the therapy of GBM. Here, we hypothesized PAX3/p53 axis promoted the process of differentiation, regulating to the cancer stem cell properties, such as proliferation and migration. The correlation between PAX3 and p53 in GBM were first clarified. Immunofluorescence of p53 was shown activated following BGSCs differentiation. We further identified that PAX3 might specifically bind to the promoter of p53 gene, and transcriptionally repressed p53 expression. ChIP assay further confirmed that PAX3/p53 axis regulated the differentiation process of BGSCs. Then, the function of PAX3 in BGSCs were sequentially investigated in vitro and in vivo. Ectopic PAX3 expression promoted BGSCs growth and migration while PAX3 knockdown suppressed BGSCs growth, migration in vitro and in vivo. Similar to PAX3 overexpression, p53 inhibition also showed increase in growth and migration of differentiated BGSCs. Regarding the functional interaction between PAX3 and p53, PAX3 knockdown-mediated decrease in proliferation was partially rescued by p53 inhibition. Hypoxia significantly promoted the migration potential of BGSCs. In addition, hypoxia inducible factor-1α (HIF-1α) might be a potential upstream regulator of PAX3 in differentiated BGSCs under hypoxia. Our work may provide a supplementary mechanism in regulation of the BGSCs differentiation and their functions, which should provide novel therapeutic targets for GBM in future.

Analysis of influencing factors of severity in acute pancreatitis using big data mining

SUMMARY OBJECTIVES To evaluate the epidemiological characteristics of acute pancreatitis (AP) and explore potential relationships between these factors and severity. METHODOLOGY Data-sets of 5,659 patients with AP from health statistics and the Information Center of Jiangsu province, between 2014 and 2016, were analyzed. A self-organizing map (SOM) neural network was used for data clustering. RESULTS Biliary acute pancreatitis (BAP) (86.7%) was the most frequent etiological factor. A total of 804 (14.2%) patients had severe acute pancreatitis (SAP). The mean age of patients was 53.7 + 17.3 (range 12~94y). Most of the AP patients were married (75.4%); 6% of mild /moderately severe AP (MAP/MASP) patients were unmarried, which was less than SAP patients (P=0.016). AP patients with blood type AB in the general population (8.8%) was significantly lower than that of AP cases (13.9%) (P=0.019) and SAP cases(18.7%) (P=0.007). The number of AP patients in southern Jiangsu was much higher than that in northern Jiangsu province, especially in Nanjing (1229, 21.7%). The proportion of acute alcoholic pancreatitis (AAP) in the north of Jiangsu (Xuzhou 18.4%) was much higher than that in southern Jiangsu (Suzhou 2.6%). The whole sample was divided into five classes by SOM neural network. If BAP patients were male, old, divorced, and blood type AB or B, they were more likely to develop SAP. Middle-age, unmarried or divorced male patients with blood type B/AB who suffered from HAP or AAP were also more likely to develop SAP. CONCLUSIONS The number of unmarried patients with MAP/MASP was smaller than that of SAP. Blood types AB and B were more frequent in AP, especially in SAP. The differences between southern Jiangsu and northern Jiangsu, in number of AP patients and the proportion of AAP, were significant. In class I and class IV, the ratio of SAP was much higher than in other classes and the whole sample.

Electrospun silk fibroin-based neural scaffold for bridging a long sciatic nerve gap in dogs.

Silk fibroin (SF)-derived silkworms represent a type of highly biocompatible biomaterial for tissue engineering. We have previously investigated biocompatibility of SF with neural cells isolated from the central nervous system or peripheral nerve system in vitro, and also developed a SF-based nerve graft conduit or tissue-engineered nerve grafts by introducing bone marrow mesenchymal stem cells, as support cells, into SF-based scaffold and evaluated the outcomes of peripheral nerve repair in a rat model. As an extension of the previous study, the electrospun technique was performed here to fabricate SF-based neural scaffold inserted with silk fibres for bridging a 30-mm-long sciatic nerve gap in dogs. Assessments including functional, histological and morphometrical analyses were applied 12 months after surgery. All the results indicated that the SF-based neural scaffold group achieved satisfactory regenerative outcomes, which were close to those achieved by autologous nerve grafts as the golden-standard for peripheral nerve repair. Overall, our results raise a potential possibility for the translation of SF-based electrospun neural scaffolds as an alternative to nerve autografts into the clinic.

Bone marrow mesenchymal stem cell-derived acellular matrix-coated chitosan/silk scaffolds for neural tissue regeneration.

Extracellular/acellular matrix-containing neural scaffolds represent a promising design of a tissue engineered nerve graft (TENG) for peripheral nerve repair. In this study, we engineered a composite neural scaffold by culturing dog bone marrow mesenchymal stem cells (BMSCs) onto the surface of a chitosan/silk fibroin-based scaffold and then exposing the cell culture to decellularization to deposit acellular matrix (ACM) coatings on the scaffold. This natural biomaterial-based, cell-derived ACM-coated neural scaffold, as a novel nerve graft, was used to bridge a 60 mm long nerve gap in a dog sciatic nerve. At 12 months after grafting, behavioral, functional, and histological evaluation indicated that our developed neural scaffold achieved satisfactory regenerative outcomes, which were very close to those achieved by autologous nerve grafts, the accepted golden standard for peripheral nerve repair. Moreover, additional therapeutic benefits produced by the modification of a neural scaffold with BMSC-derived ACM may be associated with the unique neural activity of the ACM, as evidenced by in vitro experimental findings that the ACM significantly enhanced axonal regrowth and Schwann cell proliferation. Our results will provide a further experimental basis for the translation of ACM-containing neural scaffolds into the clinic.

Angiogenesis in tissue-engineered nerves evaluated objectively using MICROFIL perfusion and micro-CT scanning.

Angiogenesis is a key process in regenerative medicine generally, as well as in the specific field of nerve regeneration. However, no convenient and objective method for evaluating the angiogenesis of tissue-engineered nerves has been reported. In this study, tissue-engineered nerves were constructed in vitro using Schwann cells differentiated from rat skin-derived precursors as supporting cells and chitosan nerve conduits combined with silk fibroin fibers as scaffolds to bridge 10-mm sciatic nerve defects in rats. Four weeks after surgery, three-dimensional blood vessel reconstructions were made through MICROFIL perfusion and micro-CT scanning, and parameter analysis of the tissue-engineered nerves was performed. New blood vessels grew into the tissue-engineered nerves from three main directions: the proximal end, the distal end, and the middle. The parameter analysis of the three-dimensional blood vessel images yielded several parameters, including the number, diameter, connection, and spatial distribution of blood vessels. The new blood vessels were mainly capillaries and microvessels, with diameters ranging from 9 to 301 µm. The blood vessels with diameters from 27 to 155 µm accounted for 82.84% of the new vessels. The microvessels in the tissue-engineered nerves implanted in vivo were relatively well-identified using the MICROFIL perfusion and micro-CT scanning method, which allows the evaluation and comparison of differences and changes of angiogenesis in tissue-engineered nerves implanted in vivo.

Repair of Rat Sciatic Nerve Defects by Using Allogeneic Bone Marrow Mononuclear Cells Combined With Chitosan/Silk Fibroin Scaffold.

The therapeutic benefits of bone marrow mononuclear cells (BM-MNCs) in many diseases have been well established. To advance BM-MNC-based cell therapy into the clinic for peripheral nerve repair, in this study we developed a new design of tissue-engineered nerve grafts (TENGs), which consist of a chitosan/fibroin-based nerve scaffold and BM-MNCs serving as support cells. These TENGs were used for interpositional nerve grafting to bridge a 10-mm-long sciatic nerve defect in rats. Histological and functional assessments after nerve grafting showed that regenerative outcomes achieved by our developed TENGs were better than those achieved by chitosan/silk fibroin scaffolds and were close to those achieved by autologous nerve grafts. In addition, we used green fluorescent protein-labeled BM-MNCs to track the cell location within the chitosan/fibroin-based nerve scaffold and trace the cell fate at an early stage of sciatic nerve regeneration. The result suggested that BM-MNCs could survive at least 2 weeks after nerve grafting, thus helping to gain a preliminary mechanistic insight into the favorable effects of BM-MNCs on axonal regrowth.

Long-term outcome of the repair of 50 mm long median nerve defects in rhesus monkeys with marrow mesenchymal stem cells-containing, chitosan-based tissue engineered nerve grafts.

Despite great progress in the fields of tissue engineering and stem cell therapy, the translational and preclinical studies are required to accelerate the clinical application of tissue engineered nerve grafts, as an alternative to autologous nerve grafts, for peripheral nerve repair. Rhesus monkeys (non-human primates) are more clinically relevant and more suitable for scaling up to humans as compared to other mammalians. Based on this premise, and considering a striking similarity in the anatomy and function between human and monkey hands, here we used chitosan/PLGA-based, autologous marrow mesenchymal stem cells (MSCs)-containing tissue engineered nerve grafts (TENGs) for bridging a 50-mm long median nerve defect in rhesus monkeys. At 12 months after grafting, locomotive activity observation, electrophysiological assessments, and FG retrograde tracing tests indicated that the recovery of nerve function by TENGs was more efficient than that by chitosan/PLGA scaffolds alone; histological and morphometric analyses of regenerated nerves further confirmed that the morphological reconstruction by TENGs was close to that by autografts and superior to that by chitosan/PLGA scaffolds alone. In addition, blood test and histopathological examination demonstrated that TENGs featured by addition of autologous MSCs could be safely used in the primate body. These findings suggest the efficacy of our developed TENGs for peripheral nerve regeneration and their promising perspective for clinical applications.

Joint use of a chitosan/PLGA scaffold and MSCs to bridge an extra large gap in dog sciatic nerve.

BACKGROUND: Tissue-engineered nerve grafts (TENGs) constitute a promising alternative to nerve autografts that are recognized as the gold standard for surgical repair of peripheral nerve gaps. OBJECTIVE: To investigate the feasibility of using TENGs for bridging extra large peripheral nerve gaps in large animals. METHODS: TENGs were constructed by incorporating autologous bone marrow mesenchymal stem cells (MSCs) into a neural scaffold that consisted of a chitosan conduit inserted with poly(lactic-co-glycolic acid) (PLGA) fibers. A 60-mm-long sciatic nerve gap in dogs was bridged by TENGs, chitosan/PLGA scaffolds, or nerve autografts. At 12 months postsurgery, behavioral analysis, electrophysiology, retrograde fluorogold tracing, and histological examination were performed. RESULTS: The outcomes of TENGs were similar to those of autografts and better than those of scaffolds alone. CONCLUSION: Introduction of autologous MSCs to a chitosan/PLGA scaffold improved the repair and rehabilitation of a large gap after peripheral nerve injury in dogs. Autologous MSCs may be a source of support cells for neural tissue engineering.

Chemoprotective effect of N-acetylcysteine (NAC) on cellular oxidative damages and apoptosis induced by nano titanium dioxide under UVA irradiation.

The chemoprotective effect of N-acetylcysteine (NAC), a sulfhydryl-containing antioxidant, on nano titanium dioxide (nano-TiO(2)) induced oxidative stress and apoptosis in human keratinocyte (HaCaT) cells was assessed. HaCaT cells were pretreated with NAC followed by treatment with 200 µg/ml nano-TiO(2), then exposed to ultraviolet A (UVA, 365 nm) for 1 h and cultured for 24 h. Intracellular reactive oxygen species (ROS) and nitric oxide (NO) formation, mitochondrial membrane potential (MMP), apoptosis and the content of the lipid peroxidation product malondialdehyde (MDA) were measured. Keratin 6 (K6) mRNA expression was also analyzed. The results showed that NAC strongly inhibited ROS and NO production in nano-TiO(2) treated cells. The extent of lipid peroxidation was also decreased in the presence of NAC. In addition, NAC suppressed nano-TiO(2) induced apoptosis and increased K6 mRNA expression. The results indicated that NAC could prevent oxidative stress and apoptosis induced by nano-TiO(2) in HaCaT cells.