Addition Of Mesenchymal Stem Cells Research Articles

The addition of mesenchymal stem cells in a bioabsorbable scaffold does not enhance tendon healing after a repair of rotator cuff tear.

The purpose of the study is to evaluate the healing potential of a full-thickness tendon defect in the rotator cuff of rabbits using a bioabsorbable scaffold impregnated with bone marrow-mesenchymal stem cells (BM-MSCs) or rotator cuff-derived mesenchymal stem cells (RC-MSCs). Sixteen adult rabbits were subjected to a full-thickness rotator cuff deficit. Rabbits were randomly assigned to four groups of four animals. In Group 0 (control), the deficit was left untreated. In Group 1, the deficit was treated with a single synthetic scaffold alone. In Group 2, the deficit was treated with the previous scaffold loaded with allogeneic BM-MSCs. In Group 3, the deficit was treated with the previous scaffold loaded with allogenic RC-MSCs. After animal sacrifice, tissue samples were subjected to histological and immunohistochemical analysis. Group 1 showed the highest mean tendon maturing score (15.3 ± 0.9) postoperatively, being significantly higher, in comparison to groups 0, 2 and 3 (p = 0.01, 0.02 and 0.01, respectively). Group 1 showed the highest mean collagen I/collagen III ratio (1.4 ± 0.8) postoperatively but without any statistical significance. The utilization of MSCs in rotator cuff repair in a rabbit model has not been associated with an enhancement in tendon healing in 16 weeks postoperatively, in comparison to controls and bioabsorbable scaffolds. The addition of MSCs does not result in better rotator cuff healing. Not applicable. This is an animal study.

Abstract 337: A metastatic phenotype is reproduced in spheroids containing patient-specific cancer cells and mesenchymal stem cells

Abstract Reproducible, scalable, and patient-specific 3D models of the tumor microenvironment are required to study tumor growth, metastasis and dormancy. In this study, patient-derived cancer cells, mesenchymal stem cells (MSCs), and optimization of the oxygen level and extracellular matrix (ECM) were incorporated in the development of a spheroid system using 5 cancer cell models (pancreatic [Panc], lung adenocarcinoma [LA], colon adenocarcinoma [CA], endometrioid ovarian [EO] and high-grade serous carcinoma [HGSC]). The cell models were isolated and scaled up using a feeder-free culture medium in either ambient oxygen (approximately 21% O2) or hypoxic (5% O2) conditions, depending on the individual model requirements. Cell migration was assessed via monolayer scratch assays, and the relative rates were compared to the T stage of the tumor from which the models were derived. To assess spheroid formation, the 5 models were cultured in ECM-containing medium. The Panc and HGSC spheroids were also generated with the addition of MSCs at ratios of 1-100 MSCs per 100 cancer cells. The relative rates of migration of the cell models in ambient oxygen (CA > EO ≈ Panc > HGSC ≈ LA) differed significantly from that in 5% O2 (CA = Panc = HGSC > EO > LA). Interestingly, the T stage of the original tumors (CA = Panc = HGSC > LA > EO) correlated more closely to the relative rate of cell migration when the cell models were cultured in 5% compared to 21% O2. When cultured in a 3D (spheroid) format containing ECM, the Panc and EO models demonstrated increased invasion into the surrounding ECM compared to the LA, HGSC, and CA models. The addition of MSCs into the LA model dramatically increased the invasive phenotype of the LA model. A seeding ratio of 1:100 MSC:LA cells enabled spheroid formation and invasion into the ECM, previously unobserved for the LA model in this format. The Panc model became extremely aggressive with respect to invasion into the ECM, at a ratio as low as 1:100 MSCs to cancer cells. In pilot studies with the Panc and HGSC models, spheroid size and invasion into the ECM increased upon adding the MSCs. Spheroid diameter increased by approximately 30%, and there was a notable increase in invasiveness of the already mobile and invasive Panc cancer cells into the surrounding ECM. We present here an efficient, patient-specific, spheroid model system representing dormant and metastatic tumor states that is suitable for studying antitumor drug response, personalized therapy, and disease mechanisms. The relative rates of cell migration positively correlated with the T stage of the original tumors in the more physiologically-relevant oxygen condition (5%), underscoring the need to optimize this parameter during model development. Continued optimization will include incorporating tissue-specific ECMs from lung, liver and pancreas, and assessing the robustness and scalability of these models for high-throughput drug screens. Citation Format: Dmitry Shvartsman, Amy Pepicelli, Liam Deems, David Deems, Elin S. Agoston, Amit Shahar. A metastatic phenotype is reproduced in spheroids containing patient-specific cancer cells and mesenchymal stem cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 337.

Efficacy of Mesenchymal Stem Cells in Bronchiolitis Obliterans Syndrome after Allogeneic HSCT: A Multicenter Prospective Cohort Study

Background: Bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a devastating complication with limited therapeutic options. We aimed to assess the efficacy and safety of mesenchymal stem cells (MSCs) in BOS after allo-HSCT. Methods: Eighty-one allo-HSCT recipients with BOS diagnosed within 6 months were enrolled in this multicenter prospective cohort study. The choice of prednisone and azithromycin combined with or without MSCs was based on patient preferences (MSC n=49, non-MSC n=32). The primary endpoint was response rate at 3 months, defined as the proportion of patients achieving FEV1 improvement or steroid sparing. This trial was registered at ClinicalTrials.gov, NCT02543073. Results: Response rate was 35/49 patients (71%, 95% confidence intervals [CI] 59 to 84%) (FEV1 improvement n=10, steroid sparing n=25) and 14/32 (44%, 95% CI 27 to 61%) (FEV1 improvement n=3, steroid sparing n=11) in the MSC and non-MSC group, respectively (p=0.013). The adjusted odds ratio of response in the MSC group compared with the non-MSC group was 3.32 (95% CI 1.21-9.11; p=0.02). The addition of MSCs was associated with a better difference for change in FEV1 rate of decline, compared to non-MSC group (53 ml/months, 2 to 103; p=0.040). The 3-year overall survival post-diagnosis was 70.6% (95% CI 55.9 to 85.3%) and 58.2% (95% CI 36.1 to 78.5%) in the MSC and non-MSC group, respectively (p=0.21). Clinical improvement was accompanied by a significant increase of interleukin (IL)-10-producing CD5+ B cells. The incidences of infection and leukemia relapse were no significant difference between two groups. Multiple infusions of MSCs were well-tolerated with no serious adverse events. Interpretation: MSCs might be an effective and safe therapy for BOS patients after allo-HSCT. Our study strengthens evidence for clinical practice of MSC therapy in BOS. These data also offer insight into potential biological mechanisms of MSC treatment and support further investigation in larger randomized controlled trials. Disclosures No relevant conflicts of interest to declare.

First Clinical Application of Polyurethane Meniscal Scaffolds with Mesenchymal Stem Cells and Assessment of Cartilage Quality with T2 Mapping at 12 Months.

Complex meniscal lesions often require meniscectomy with favorable results in the short term but a high risk of early osteoarthritis subsequently. Partial meniscectomy treated with meniscal substitutes may delay articular cartilage degeneration. To evaluate the status of articular cartilage by T2 mapping after meniscal substitution with polyurethane scaffolds enriched with mesenchymal stem cells (MSC) and comparison with acellular scaffolds at 12 months. Seventeen patients (18-50 years) with past meniscectomies were enrolled in 2 groups: (1) acellular polyurethane scaffold (APS) or (2) polyurethane scaffold enriched with MSC (MPS). Patients in the MPS group received filgrastim to stimulate MSC production, and CD90+ cells were obtained and cultured in the polyurethane scaffold. The scaffolds were implanted arthroscopically into partial meniscus defects. Concomitant injuries (articular cartilage lesions or cartilage lesions) were treated during the same procedure. Changes in the quality of articular cartilage were evaluated with T2 mapping in femur and tibia at 12 months. In tibial T2 mapping, values for the MPS group increased slightly at 9 months but returned to initial values at 12 months (P > 0.05). In the APS group, a clear decrease from 3 months to 12 months was observed (P > 0.05). This difference tended to be significantly lower in the APS group compared with the MPS group at the final time point (P = 0.18). In the femur, a slight increase in the MPS group (47.8 ± 3.4) compared with the APS group (45.3 ± 4.9) was observed (P > 0.05). Meniscal substitution with polyurethane scaffold maintains normal T2 mapping values in adjacent cartilage at 12 months. The addition of MSC did not show any advantage in the protection of articular cartilage over acellular scaffolds (P > 0.05).

The Efficacy of Mesenchymal Stem Cells in Bronchiolitis Obliterans Syndrome after Allogeneic HSCT: A Multicentre Prospective Cohort Study

Background: Bronchiolitis obliterans syndrome (BOS) after allo-HSCT is a devastating complication with limited therapeutic options. We aimed to assess the efficacy and safety of mesenchymal stem cells (MSCs) in BOS after allo-HSCT. Methods: Eighty-one allo-HSCT recipients with BOS diagnosed within 6 months were enrolled in this multicentre prospective cohort study. The choice of prednisone and azithromycin combined with or without MSCs was based on patient preferences (MSC n=49, non-MSC n=32). The primary endpoint was response rate at 3 months, defined as the proportion of patients achieving FEV1 improvement or steroid sparing. Findings: Response rate was 35/49 patients (71%, 95% CI 59 to 84%) and 14/32 (44%, 27 to 61%) in MSC and non-MSC group, respectively (p=0*013). The addition of MSCs was associated with a better difference for change in FEV1 rate of decline, compared to non-MSC group (53 ml/months, 2 to 103; p=0*040). The 3-year overall survival post-diagnosis was 70*6% (55*9 to 85*3%) and 58*2% (36*1 to 78*5%) in MSC and non-MSC group, respectively (p=0*21). Clinical improvement was accompanied by a significant increase of interleukin (IL)-10-producing CD5+B cells. Infections and leukemia relapse were no significant difference between two groups. MSCs were well-tolerated with no serious adverse events. Interpretation: MSCs might be an effective and safe therapy for BOS after allo-HSCT. These data also offer insight into potential biological mechanisms of MSC treatment and support further investigation in larger randomized controlled trials. Our study strengthens evidence for clinical practice of MSC therapy in BOS. Trial Registration: This trial is registered with ClinicalTrials.gov, NCT02543073. Funding Statement: This study was supported by the National Key R&D Program of China (2017YFA105500 and 2017YFA105504), the National Natural Science Foundation of China (81770190 and 81700176), the Health Collaborative Innovation Major Projects of Guangzhou City (201508020254), the Science and Technology Planning Project of Guangdong Province (2014B020226004). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: The protocol was approved by institutional review board at each centre. Written informed consents were obtained from all participants in accordance with the Helsinki Declaration.

Mesenchymal stem cells may ameliorate inflammation in an ex vivo model of extracorporeal membrane oxygenation.

Mesenchymal stem cells exhibit immunomodulatory properties which are currently being investigated as a novel treatment option for Acute Respiratory Distress Syndrome. However, the feasibility and efficacy of mesenchymal stem cell therapy in the setting of extracorporeal membrane oxygenation is poorly understood. This study aimed to characterise markers of innate immune activation in response to mesenchymal stem cells during an ex vivo simulation of extracorporeal membrane oxygenation. Ex vivo extracorporeal membrane oxygenation simulations (n = 10) were conducted using a commercial extracorporeal circuit with a CO2-enhanced fresh gas supply and donor human whole blood. Heparinised circuits (n = 4) were injected with 40 × 106-induced pluripotent stem cell-derived human mesenchymal stem cells, while the remainder (n = 6) acted as controls. Simulations were maintained, under physiological conditions, for 240 minutes. Circuits were sampled at 15, 30, 60, 120 and 240 minutes and assessed for levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumour necrosis factor-α, transforming growth factor-β1, myeloperoxidase and α-Defensin-1. In addition, haemoglobin, platelet and leukocyte counts were performed. There was a trend towards reduced levels of pro-inflammatory cytokines in mesenchymal stem cell-treated circuits and a significant increase in transforming growth factor-β1. Blood cells and markers of neutrophil activation were reduced in mesenchymal stem cell circuits during the length of the simulation. As previously reported, the addition of mesenchymal stem cells resulted in a reduction of flow and increased trans-oxygenator pressures in comparison to controls. The addition of mesenchymal stem cells during extracorporeal membrane oxygenation may cause an increase in transforming growth factor-β1. This is despite their ability to adhere to the membrane oxygenator. Further studies are required to confirm these findings.

Biofunctionalized Scaffold in Bone Tissue Repair.

Bone tissue engineering is based on bone grafting to repair bone defects. Bone graft substitutes can contribute to the addition of mesenchymal stem cells (MSCs) in order to enhance the rate and the quality of defect regeneration. The stem cell secretome contains many growth factors and chemokines, which could affect cellular characteristics and behavior. Conditioned medium (CM) could be used in tissue regeneration avoiding several problems linked to the direct use of MSCs. In this study, we investigated the effect of human periodontal ligament stem cells (hPDLSCs) and their CM on bone regeneration using a commercially available membrane scaffold Evolution (EVO) implanted in rat calvarias. EVO alone or EVO + hPDLSCs with or without CM were implanted in Wistar male rats subjected to calvarial defects. The in vivo results revealed that EVO membrane enriched with hPDLSCs and CM showed a better osteogenic ability to repair the calvarial defect. These results were confirmed by acquired micro-computed tomography (CT) images and the increased osteopontin levels. Moreover, RT-PCR in vitro revealed the upregulation of three genes (Collagen (COL)5A1, COL16A1 and transforming growth factor (TGF)β1) and the down regulation of 26 genes involved in bone regeneration. These results suggest a promising potential application of CM from hPDLSCs and scaffolds for bone defect restoration and in particular for calvarial repair in case of trauma.

The Use of Growth Factors and Mesenchymal Stem Cells in Orthopaedics: In particular, their use in Fractures and Non-Unions: A Systematic Review.

The aim was to look at current evidence for treating non-unions or delayed fracture healing in regard to novel methods applying mesenchymal stem cells (MSCs) and growth factors (GF). Pre-clinical and clinical trials focusing on the use of Mesenchymal Stem Cells and Growth Factors for fracture healing were included in this review. Published articles were identified using specific search terms in Medline, Cochrane Library, PubMed, Scopus and Web of Science. Of the 580 articles found, 82 met my selection criteria and were included, with 39 papers involving trials on the effects of GFs and MSCs on non-unions or bone repair. These included 11 articles on MSCs, 10 on Bone Morphogenetic Proteins, 2 on Vascular-Endothelial GF, 5 on Insulin like-GF, 4 on Transforming-GF-β, 4 on Platelet-Rich Plasma, 1 on Platelet Derived-GF and 2 on Fibroblast-GF, with the other articles included qualitatively. Overall results were positive with the addition of MSCs, Bone Morphogenetic Proteins, VEGF, IGF and TGF-β in aiding fracture healing compared to controls, with mixed results for other factors. Overall this review shows promising results regarding the use of MSCs and various Growth factors in the treatment of fractures and non-unions, as well as synergistic effects observed when combined together. However more research is indicated as these methods are still in the early stages of development.

Aging and Cell Therapy for the Treatment of Osteonecrosis of the Femoral Head

The addition of mesenchymal stem cells (MSCs) to core decompression for the treatment of early-stage osteonecrosis of the femoral head (ONFH) represents a joint preserving operation to potentially avoid hip arthroplasty. The idea to regenerate the proximal femoral bone stock by replenishing the necrotic segment with viable MSCs has shown great promise compared with core decompression alone. However, the fate of the MSCs and the potential effects of aging have posed some important challenges. Aging affects the number of MSCs available for harvesting and injection, as well as their potential for differentiation into the osteogenic lineage, which are two critical parameters for the success of “cell-based therapy” for ONFH. This review endeavors to provide information relevant to the use of MSCs in aging patients for the treatment of ONFH.

Wound Dressings: A Comprehensive Review

This comprehensive review covers the advantage and limitations of some dressing materials and the current knowledge on wound dressings and emerging technologies to achieve proper wound healing. Traditional and modern dressings are helpful in the wound healing process; however, they cannot substitute lost tissue. Human skin equivalents have been developed conceptually to fill this void as they do not only facilitate wound healing but also may replace lost tissue. Several studies have shown that the addition of mesenchymal stem cells, such as in human placenta, has promising results in wound healing. A wound is defined as a disruption in the continuity of the skin or mucosa due to physical or thermal damage, or an underlying medical condition. Wound healing is a complex, dynamic, and multistep process which occurs after skin damage leading to tissue repair. Although the skin normally undergoes repair after a disruption, the healing process can be affected in different conditions such as diabetes mellitus, infections, venous/arterial insufficiency, among others. To enhance healing, a wide range of wound dressings are available; however, a thorough wound assessment (e.g., wound type, size, depth, or color) is required to choose the appropriate dressing. The emergence of new dressings has brought a new perspective of wound healing, but there is no superior product yet to treat acute and/or chronic wounds. Therefore, wound dressing research studies need to be carried out in order to help improve wound healing.

The Use of Growth Factors and Mesenchymal Stem Cells in Orthopaedics

Abstract Aim The aim was to look at current evidence for treating non-unions or delayed fracture healing in regard to novel methods applying mesenchymal stem cells (MSCs) and growth factors (GF). Methods Pre-clinical and clinical trials focusing on the use of Mesenchymal Stem Cells and Growth Factors for fracture healing were included in this review. Published articles were identified using specific search terms in Medline, Cochrane Library, PubMed, Scopus and Web of Science. Results Of the 580 articles found, 82 met my selection criteria and were included, with 39 papers involving trials on the effects of GFs and MSCs on non-unions or bone repair. These included 11 articles on MSCs, 10 on Bone Morphogenetic Proteins, 2 on Vascular-Endothelial GF, 5 on Insulin like-GF, 4 on Transforming-GF-β, 4 on Platelet-Rich Plasma, 1 on Platelet Derived-GF and 2 on Fibroblast-GF, with the other articles included qualitatively. Overall results were positive with the addition of MSCs, Bone Morphogenetic Proteins, VEGF, IGF and TGF-β in aiding fracture healing compared to controls, with mixed results for other factors. Conclusion Overall this review shows promising results regarding the use of MSCs and various Growth factors in the treatment of fractures and non-unions, as well as synergistic effects observed when combined together. However more research is indicated as these methods are still in the early stages of development.

Effect of Mesenchymal Stem Cell Application on the Distracted Bone Microstructure: An Experimental Study

Distraction osteogenesis (DO) is a surgical technique used to regenerate bone. The aim of this study was to improve bone quality and quantity during DO by the addition of mesenchymal stem cells (MSCs). The study was conducted on 12 goats assigned to a study group or a control group. In the study group, DO was aided with MSCs. Bone quality was assessed using energy dispersive x-ray (EDX), a scanning electron microscope (SEM), and histology. The histologic assessment was performed by measuring trabecular bone (TB) thickness in sections stained with hematoxylin and eosin (H&E) and by measuring osteoid bone percentage in sections stained with Masson trichrome (MT). EDX showed an increase in calcification in the study group (mean Ca(2+), 17.58%; standard deviation [SD], 4.9%) compared with the control group (mean Ca(2+), 14.17%; SD, 6.7%). However, the increase was not statistically significant (P= .3354). Histomorphometric analysis of the H&E samples showed an increase in TB size in the study group (mean TB, 174.7μm; SD, 33.5μm) compared with the control group (mean TB, 115.4μm; SD, 19.6μm), and the increase was highly statistically significant (P= .0039). Analysis of the MT samples showed a decrease in osteoid percentage (mean osteoid percentage, 13.4%; SD, 2%) in the study group compared with the control group (mean osteoid percentage, 27.3%; SD, 3.5%). The decrease in osteoid percentage was statistically significant (P= .0001), indicating more rapid healing in the study group compared with the control group. MSCs improved the bone quality of distracted bone and increased the crystal density in SEM images of the study group compared with that of the control group. MSCs showed promising results in improving the quality and quantity of distracted bone.

Addition of Mesenchymal Stem Cells to Autologous Platelet-Enhanced Fibrin Scaffolds in Chondral Defects: Does It Enhance Repair?

The chondrogenic potential of culture-expanded bone-marrow-derived mesenchymal stem cells (BMDMSCs) is well described. Numerous studies have also shown enhanced repair when BMDMSCs, scaffolds, and growth factors are placed into chondral defects. Platelets provide a rich milieu of growth factors and, along with fibrin, are readily available for clinical use. The objective of this study was to determine if the addition of BMDMSCs to an autologous platelet-enriched fibrin (APEF) scaffold enhances chondral repair compared with APEF alone. A 15-mm-diameter full-thickness chondral defect was created on the lateral trochlear ridge of both stifle joints of twelve adult horses. In each animal, one defect was randomly assigned to receive APEF+BMDMSCs and the contralateral defect received APEF alone. Repair tissues were evaluated one year later with arthroscopy, histological examination, magnetic resonance imaging (MRI), micro-computed tomography (micro-CT), and biomechanical testing. The arthroscopic findings, MRI T2 map, histological scores, structural stiffness, and material stiffness were similar (p > 0.05) between the APEF and APEF+BMDMSC-treated repairs at one year. Ectopic bone was observed within the repair tissue in four of twelve APEF+BMDMSC-treated defects. Defects repaired with APEF alone had less trabecular bone edema (as seen on MRI) compared with defects repaired with APEF+BMDMSCs. Micro-CT analysis showed thinner repair tissue in defects repaired with APEF+BMDMSCs than in those treated with APEF alone (p < 0.05). APEF alone resulted in thicker repair tissue than was seen with APEF+BMDMSCs. The addition of BMDMSCs to APEF did not enhance cartilage repair and stimulated bone formation in some cartilage defects. APEF supported repair of critical-size full-thickness chondral defects in horses, which was not improved by the addition of BMDMSCs. This work supports further investigation to determine whether APEF enhances cartilage repair in humans.

Can mesenchymal stem cells reverse chronic stress-induced impairment of lung healing following traumatic injury?

One week following unilateral lung contusion (LC), rat lungs demonstrate full histologic recovery. When animals undergo LC plus the addition of chronic restraint stress (CS), wound healing is significantly delayed. Mesenchymal stem cells (MSCs) are pluripotent cells capable of immunomodulation, which have been the focus of much research in wound healing and tissue regeneration. We hypothesize that the addition of MSCs will improve wound healing in the setting of CS. Male Sprague-Dawley rats (n = 6-7 per group) were subjected to LC/CS with or without the injection of MSCs. MSCs were given as a single intravenous dose of 5 × 10 cells in 1 mL Iscove's Modified Dulbecco's Medium at the time of LC. Rats were subjected to 2 hours of restraint stress on Days 1 to 6 following LC. Seven days following injury, rats were sacrificed, and the lungs were examined for histologic evidence of wound healing using a well-established histologic lung injury score (LIS) to grade injury. LIS examines inflammatory cells/high-power field (HPF) averaged over 30 fields, interstitial edema, pulmonary edema, and alveolar integrity, with scores ranging from 0 (normal) to 11 (highly damaged). Peripheral blood was analyzed by flow cytometry for the presence of T-regulatory (C4CD25FoxP3) cells. Data were analyzed by analysis of variance followed by Tukey's multiple comparison test, expressed as mean (SD). As previously shown, 7 days following isolated LC, LIS has returned to 0.83 (0.41), with a subscore of zero for inflammatory cells/HPF. The addition of CS results in an LIS of 4.4 (2.2), with a subscore of 1.9 (0.7) for inflammatory cells/HPF. Addition of MSC to LC/CS decreased LIS to 1.7 (0.8), with a subscore of zero for inflammatory cells/HPF. Furthermore, treatment of animals undergoing LC/CS with MSCs increased the %T-regulatory cells by 70% in animals undergoing LC/CS alone (12.9% [2.4]% vs. 6.2% [1.3%]). Stress-induced impairment of wound healing is reversed by the addition of MSCs given at the time of injury in this rat LC model. This improvement in lung healing is associated with a decrease in the number of inflammatory cells and an increase in the number of T-regulatory cells. Further study into the mechanisms by which MSCs hasten wound healing is warranted.

Bone marrow mesenchymal stem cell and vein conduit on sciatic nerve repair in rats.

Background:Peripheral nerve repair with sufficient functional recovery is an important issue in reconstructive surgery. Stem cells have attracted extensive research interest in recent years.Objectives:The purpose of this study was to compare the vein conduit technique, with and without the addition of mesenchymal stem cells in gap-less nerve injury repair in rats.Materials and Methods:In this study, 36 Wistar rats were randomly allocated to three groups: In the first group, nerve repair was performed with simple neurorrhaphy (control group), in the second group, nerve repair was done with vein conduit over site (vein conduit group) and in the third group, bone marrow stem cells were instilled into the vein conduit (stem cell group) after nerve repair with vein conduit over site. Six weeks after the intervention, the sciatic function index, electrophysiological study and histological examination were performed.Results:All animals tolerated the surgical procedures and survived well. The sciatic function index and latency were significantly improved in the vein conduit (P = 0.04 and 0.03, respectively) and stem cell group (P = 0.02 and 0.03, respectively) compared with the control group. No significant difference was observed in sciatic function and latency between the vein conduit and stem-cell groups. Moreover, histological analysis showed no significant difference in regenerative density between these two groups.Conclusions:The results of this study showed that the meticulous microsurgical nerve repair, which was performed using the vein tubulization induced significantly better sciatic nerve regeneration. However, the addition of bone marrow mesenchymal stem cell to vein conduit failed to promote any significant changes in regeneration outcome.

Efecto de la adición de fracción vasculoestromal de grasa a la sutura de lesiones meniscales crónicas en zona avascular del menisco de cerdo

ObjectiveThe addition of mesenchymal stem cells may increase the chance of healing of meniscal lesions in the avascular zone. The objective of this study is to find out if the postoperative application of the stromal vascular fraction (SVF) from adipose tissue can have an effect on vascularization and cell proliferation in the sutured meniscus. MethodsFour pigs (8 knees) underwent a longitudinal injury of 10mm in the avascular area of the medial meniscus in both knees. Two months later the injury was repaired on both knees with a simple suture. At the same time 50g of abdominal fat was removed and 2cm3 of SVF was purified (in which it was found to contain approximately 1-5×106mesenchymal stem cells). This was injected into one of the knees of each pig 4h after the surgery (SVF group), using the other knee as the control group. The animals were sacrificed after 15 days. The following histological parameters with hematoxylin-eosin staining were evaluated: degree of healing, neo-vascularization of tissue and the proliferation of fibro-chondrocytes around the lesion and the presence of new chondrocytes. ResultsThe healing rate (unhealed / partial healing / healed) for the SVF group was 1/1/2, and was 2-2-0 for control group (non-significant differences). The degree of neo-vascularization was higher in the SVF group (3.25 vs 2). The degree of fibro-chondrocytes proliferation was greater in the SVF group (2.5 vs 1.75). The formation of isogenic chondrocytes was observed in 2 menisci of the SVF group and none in the control group. ConclusionsThe postoperative intra-articular injection of SVF might increase the neovascularization, the proliferation of fibro-chondrocytes and the repopulation of chondrocytes 15 days after the repair of meniscal injury in pigs. Evidence levelExperimental study. Clinical relevanceA system for the use of stem cells is presented that might be easier to implement in humans that cell cultures.

Update on mandibular distraction osteogenesis.

Mandibular distraction osteogenesis has become one of the most powerful reconstructive tools for addressing congenital lower jaw deformities. This review will focus on clinical and basic science contributions to the literature in the last year, which have shown innovations in mandibular distraction osteogenesis techniques and advances in outcomes. The longest phase of distraction is consolidation, when newly formed bone must fully heal. If consolidation could be accelerated, the length of time required for fixation would be less and complications associated with fixation devices would decline. In the last year, animal studies were conducted reporting the application of growth factors directly to distraction gaps to accelerate bone formation. Additional research in animal models showed success with the addition of bone marrow-derived mesenchymal stem cells to the distraction gap. Distraction devices are being piloted with automated, continuous formats compared with current devices that require manual activation. The use of surgical planning software programs to determine the location of osteotomies was another focus of current studies. Rates of activation can be accelerated with the addition of stem cells and growth factors to distraction sites, as could time to full consolidation. The addition of mesenchymal stem cells and deferoxamine and the use of low-intensity ultrasound during distraction are three of the most promising approaches reported in recent studies with potential for future translation from animal models. Computer-assisted presurgical planning offers added accuracy and potential time savings. Newer distraction devices using computer automation are still in preliminary phases, but show promise.

The use of a novel bone allograft wash process to generate a biocompatible, mechanically stable and osteoinductive biological scaffold for use in bone tissue engineering.

Fresh-frozen biological allograft remains the most effective substitute for the 'gold standard' autograft, sharing many of its osteogenic properties but, conversely, lacking viable osteogenic cells. Tissue engineering offers the opportunity to improve the osseointegration of this material through the addition of mesenchymal stem cells (MSCs). However, the presence of dead, immunogenic and potentially harmful bone marrow could hinder cell adhesion and differentiation, graft augmentation and incorporation, and wash procedures are therefore being utilized to remove the marrow, thereby improving the material's safety. To this end, we assessed the efficiency of a novel wash technique to produce a biocompatible, biological scaffold void of cellular material that was mechanically stable and had osteoinductive potential. The outcomes of our investigations demonstrated the efficient removal of marrow components (~99.6%), resulting in a biocompatible material with conserved biomechanical stability. Additionally, the scaffold was able to induce osteogenic differentiation of MSCs, with increases in osteogenic gene expression observed following extended culture. This study demonstrates the efficiency of the novel wash process and the potential of the resultant biological material to serve as a scaffold in bone allograft tissue engineering.

Biological Strategies to Enhance Rotator Cuff Healing.

Rotator cuff tear causes a high rate of morbidity. After surgical repair, the presence of a scar tissue reduces tendon biomechanical properties. Emerging strategies for enhancing tendon healing are growth factors, cytokines, gene therapy and tissue engineering. However their efficacy has to be proved. Growth factors help the process of tendon healing by aiding cells chemotaxis, differentiation and proliferation. Numerous growth factors, including the bone morphogenetic proteins and platelet-derived growth factor can be found during the early healing process of a rotator cuff repair. Growth factors are delivered to the repair site using tissue-engineered scaffolding, coated sutures, or dissolved in a fibrin sealant. Platelet-rich plasma is an autologous concentration of platelets and contains an high density of growth factors. There is some evidence that platelet-rich plasma may improve pain and recovery of function in a short time period, but it does not improve healing rates in rotator cuff. Thus the routine use of platelet-rich plasma in rotator cuff repair is not recommended. The addition of mesenchymal stem cells to scaffolds can lead to the production of a better quality healing tissue. Gene therapy is a gene transfer from a cell into another, in order to over-express the gene required. In this way, cultures of stem cells can over-express growth factors. Better understanding of the mechanisms of physiological tendon healing can promote the correct use of these new biological therapies for a better healing tissue.

Cell Based Therapies as Compared to Autologous Bone Grafts for Spinal Arthrodesis

Systematic review. To compare the clinical outcome of cell based grafts combined with bone extenders to autologous bone grafts. Alternative graft options that combine mesenchymal stem cells (MSCs) and bone marrow aspirate (BMA) with synthetic or allograft scaffolds have been recently used in several animal and clinical studies. This systematic review of the literature addresses the following key questions (KQs): (1) Does the use of MSCs or BMA combined with synthetic or allograft extenders contribute to thoracolumbar fusion rates that are comparable with the rates achieved by the use of iliac crest graft? (2) Are these fusion rates comparable with those of local bone graft (LBG)? (3) Does the addition of MSCs or BMA to iliac crest bone graft or LBG contribute to better throracolumbar fusion rates? (4) Are the cervical spine fusion outcomes achieved by the use of SCM or BMA with synthetic or allograft scaffolds comparable with the iliac crest bone graft or LBG outcomes? (5) Was there any difference in terms of fusion rates, when MSCs were compared with BMA? For KQ1, 4 level II, III studies used iliac crest bone graft as control. The results of these studies were inconsistent, and the overall body of evidence was found insufficient. Three, level II, III studies were identified for KQ2. Comparable fusion rates were demonstrated between LBG and BMA combined with calcium phosphate or collagen carrier. The overall body of evidence was found weak. For KQ3, one level III study was found. No significant difference was found in the fusion rates. No studies met the criteria for KQ4, 5. The currently available evidence is insufficient to support the use of MSCs or BMA combined with synthetic or allograft materials as a substitute or supplementary graft to autologous bone graft. 2.