Case report: Magnetic resonance imaging features with postoperative improvement of atypical cervical glioma characterized by predominant extramedullary distribution in a dog.

Introduction: Intramedullary cord tumors present diagnostic and therapeutic challenges. Furthermore, spinal cord tumors can move across compartments, making antemortem diagnosis difficult, even with advanced imaging. This report presents a rare case of a cranial cervical spinal glioma, confirmed by surgical histopathology, with postoperative improvement in a dog. Case description: A 9-year-old female Maltese dog presented with kyphotic posture, progressive left hemiparesis, and decreased appetite. Neurological examination revealed neck pain and decreased proprioception in the left limbs along with intact deep pain perception. Two days later, the patient developed non-ambulatory tetraparesis. Magnetic resonance imaging (MRI) revealed an ovoid, well-defined mass with homogeneously marked contrast enhancement in the second cervical spinal cord that severely compressed the spinal cord. This mass was heterogeneously hyperintense on T2-weighted images and iso-to-hypointense on T1-weighted images, showing an appearance resembling the "golf-tee" and "dural tail" signs. The MRI findings suggested an intradural extramedullary tumor. Intraoperatively, a well-demarcated mass which was locally adherent to the spinal meninges was removed. Both histopathological and genomic tumor tests were indicative of a glioma. Approximately 2 weeks postoperatively, the patient's neurological signs returned to normal. Conclusion: This case report describes an atypical cervical glioma with complicated MR characteristics in a dog, where MRI helped guide surgical intervention.

The protective effect of cannabinoids against colorectal cancer cachexia through modulation of inflammation and immune responses.

Cancer cachexia is a multifactorial disorder characterized by weight loss and muscle wasting, and there are currently no FDA-approved medications. In the present study, upregulation of six cytokines was observed in serum samples from patients with colorectal cancer (CRC) and in mouse models. A negative correlation between the levels of the six cytokines and body mass index in CRC patients was seen. Gene Ontology analysis revealed that these cytokines were involved in regulating T cell proliferation. The infiltration of CD8+ T cells was found to be associated with muscle atrophy in mice with CRC. Adoptive transfer of CD8+ T cells isolated from CRC mice resulted in muscle wasting in recipients. The Genotype-Tissue Expression database showed that negative correlations between the expression of cachexia markers and cannabinoid receptor 2 (CB2) in human skeletal muscle tissues. Pharmacological treatment with Δ9-tetrahydrocannabinol (Δ9-THC), a selective CB2 agonist or overexpression of CB2 attenuated CRC-associated muscle atrophy. In contrast, knockout of CB2 with a CRISPR/Cas9-based strategy or depletion of CD8+ T cells in CRC mice abolished the Δ9-THC-mediated effects. This study demonstrates that cannabinoids ameliorate CD8+ T cell infiltration in CRC-associated skeletal muscle atrophy via a CB2-mediated pathway. Serum levels of the six-cytokine signature might serve as a potential biomarker to detect the therapeutic effects of cannabinoids in CRC-associated cachexia.

Stability and Activity of Interferon Beta to Treat Idiopathic Pulmonary Fibrosis with Different Nebulizer Technologies.

Background: Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by lung scarring, which results in breathing difficulty. Currently, patients with IPF exhibit a poor survival rate and have access to very limited therapeutic options. Interferon beta (IFN-ß) has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsing forms of multiple sclerosis, and it has also been shown to exhibit therapeutic potential in IPF. However, clinical use of IFN-ß did not lead to improved overall survival in IPF patients in existing studies. One possibility is the limited efficiency of IFN-ß delivery through intravenous or subcutaneous injection. Materials and Methods: The aerosol particle size distribution was determined with a laser diffraction particle size analyzer to characterize the droplet size and fine particle fraction generated by three types of nebulizers: jet, ultrasonic, and mesh. A breathing simulator was used to assess the delivery efficiency of IFN-ß, and the temperature in the medication reservoirs was monitored with a thermocouple during nebulization. To further evaluate the antifibrotic activity of IFN-ß pre- and postnebulization, bleomycin (BLM)- or transforming growth factor-beta (TGF-ß)-treated human lung fibroblast (HLF) cells were used. Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Transwell migration assay and Q-PCR analysis were used to evaluate cell migration and the myofibroblast differentiation ability, respectively. IFN-ß protein samples were prepared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample loading buffer, and the expression of IFN-ß was assessed by western blotting. Results: Among the current drug delivery systems, aerosolized medication has shown increased efficacy of drug delivery for treating respiratory diseases when compared with parenteral drugs. It was found that neither the structural integrity nor the biological function of nebulized IFN-ß was compromised by the nebulization process of the mesh nebulizer. In addition, in BLM dose-response or TGF-ß-induced lung fibroblast proliferation assays, these effects could be reversed by both parenteral and inhaled IFN-ß nebulized with the mesh nebulizer. Nebulized IFN-ß with the mesh nebulizer also significantly inhibited the migration and myofibroblast differentiation ability of TGF-ß-treated HLF cells. Conclusions: The investigations revealed the potential efficacy of IFN-ß in the treatment of IPF with the mesh nebulizer, demonstrating the higher efficiency of IFN-ß delivered through the mesh nebulizer.

Nelumbo nucifera leaf polyphenol extract and gallic acid inhibit TNF-α-induced vascular smooth muscle cell proliferation and migration involving the regulation of miR-21, miR-143 and miR-145.

Nelumbo nucifera leaf water extract (NLE) attenuates high-fat diet (HFD)-induced rabbit atherosclerosis, but its mechanism of action and the relevant compounds remain unclear. Modulating the proliferation and migration of vascular smooth muscle cells (VSMCs) may be an enforceable strategy for atherosclerosis prevention. Therefore, we investigated the potential mechanisms of N. nucifera leaf polyphenol extract (NLPE) and its active ingredient gallic acid (GA) in VSMC proliferation and migration. A7r5 rat aortic VSMCs were provoked using 50 ng mL-1 tumor necrosis factor (TNF)-α; the NLPE or GA reduced the TNF-α-induced migration by inhibiting the transforming protein RhoA/cell division cycle protein 42 pathway. The NLPE or GA suppressed the TNF-α-induced VSMC proliferation by inhibiting the Ras pathway and increasing the expression of phosphatase and tensin homolog (PTEN), kinase suppressor of Ras 2, and inducible nitric oxide synthase. The NLPE or GA increased PTEN expression by downregulating microRNA (miR)-21 expression and reduced Ras and RhoA expression by upregulating miR-143 and miR-145 expression. The NLPE and GA use potentially prevents atherosclerosis by inhibiting the VSMC migration and proliferation. The mechanisms involve the regulation of the miRNA in PTEN, the Ras/extracellular-signal-regulated kinase pathway, and Rho family proteins.

Solanum nigrum polyphenols reduce body weight and body fat by affecting adipocyte and lipid metabolism.

Obesity, being overweight and deposition of body fat are critically associated with metabolic disorders. The number of adipocytes and their lipid content, and the molecules involved in lipid metabolism are involved in obesity comorbidity. The food, Solanum nigrum L. (SN), has medical benefits in many aspects. In our recent report, SN was shown to reduce hepatic fat accumulation and oxidative stress, thus attenuating liver damage. However, it has not yet been explored whether SN is effective for weight loss and body fat reduction. Hence, we aimed to investigate if SN water extract (SWE) and the derived polyphenols (SNPE) are able to prevent obesity. Mice fed a high fat diet (HFD) and 3T3L1 cells model were used. The in vivo experiments showed SWE decreased serum triacylglyceride, cholesterol, and low-density lipoprotein (LDL)-cholesterol induced by a HFD. SWE promoted hepatic lipolysis by increasing PPARα and CPT-1, and inhibited lipogenesis by decreasing FaS and HMG-CoR. The expression of AMPK was enhanced, but sterol regulatory element binding proteins (SREBPs) were reduced by SWE, especially at 5%. In vitro analysis revealed that SNPE decreased the amount and lipid content of adipocytes. SNPE, especially at 0.5 mg mL-1, promoted lipolysis while inhibiting lipogenesis. In comparison with the doses applied in vivo and in vitro, the effect of SN could be attributed to the composition of the polyphenols. The results showed that SNPE is suggested to be an anti-obesity agent that is able to reduce body weight and body fat, by decreasing the amount and lipid content of adipocytes, and regulating lipid metabolism.

Inhibition of the Proliferation and Invasion of C6 Glioma Cells by Tricin via the Upregulation of Focal-Adhesion-Kinase-Targeting MicroRNA-7.

Tricin, a natural flavonoid present in large amounts in rice bran, was investigated for the mechanisms by which it exhibited antiproliferation and anti-invasion in C6 glioma cells. The results indicated that treatment with 5, 10, 25, and 50 µM tricin for 48 h significantly ( p < 0.05) inhibited cell numbers and colony numbers with values of 134.3 ± 5.5, 114.6 ± 2.5, 106.3 ± 3.2, and 57.3 ± 10.2, respectively. Tricin also inhibited C6-cell motility, migration, and invasion. Tricin changed the cytoskeletal organization, reduced matrix-metalloproteinase (MMP) expression, and upregulated E-cadherin. Tricin decreased FAK protein levels and suppressed focal-adhesion-kinase (FAK)-downstream-signal activation. Most importantly, tricin dose-dependently upregulated microRNA-7 (miR-7). Transfection with an miR-7 inhibitor suppressed miR-7 expression, increased FAK expression, and promoted the proliferation and invasion in C6 cells. The data support a novel anticancer mechanism of tricin that involves upregulation of FAK-targeting miR-7 in C6 glioma cells.

Mulberry Leaf Extracts prevent obesity-induced NAFLD with regulating adipocytokines, inflammation and oxidative stress.

Mulberry (Morus alba) leaf has been used in Chinese medicine as the remedy for hyperlipidemia and metabolic disorders. Recent report indicated Mulberry leaf extract (MLE) attenuated dyslipidemia and lipid accumulation in high fat diet (HFD)-fed mice. Non-alcoholic fatty liver (NAFLD) is generally considered as the liver component of metabolic syndrome. The hepatic lipid infiltration induces oxidative stress, and is associated with interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) which are regulated by the leptin and adiponectin. MLE could prevent obesity-related NAFLD via downregulating the lipogenesis enzymes while upregulating the lipolysis markers. Treatment of MLE, especially at 2%, enhanced the expression of superoxide dismutase (SOD) and clenched the oxidative stress of liver. MLE decreased the plasma level of leptin but increased adiponectin. The advantage of MLE is supposed mainly attributed to chlorogenic acid derivative. We suggest MLE, with promising outcome of research, could be nutraceutical to prevent obesity and related NAFLD.

Solanum nigrum Polyphenol Extracts Inhibit Hepatic Inflammation, Oxidative Stress, and Lipogenesis in High-Fat-Diet-Treated Mice.

Patients with diabetes, obesity, and hyperlipidemia are all high-risk groups for fatty liver; however, the mechanism of fatty liver formation is not completely understood. Studies have indicated that abnormal fat metabolism, oxidative stress, and insulin resistance are positively correlated with peroxidation and abnormal cytokine production. Recent studies have revealed that Solanum nigrum extracts (SNE) possess anti-inflammatory, antioxidation, antihyperlipidemia, and liver protection abilities. Therefore, the present study investigated the in vivo and in vitro effects of an SNE on nonalcoholic fatty liver (NAFL)-induced hepatitis. In vivo data demonstrated that the SNE reduced blood triglyceride, sugar, and cholesterol levels, as well as fat accumulation, oxidative stress, and lipid peroxidation in high-fat-diet-treated mice. The results indicated that the SNE downregulated the expression of fatty acid synthase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), and sterol regulatory element-binding proteins (SREBPs) through the AMP-activated protein kinase (AMPK) pathway and upregulated the expression of carnitine palmitoyltransferase 1 (CPT1) and peroxisome proliferator-activated receptor alpha. Furthermore, we prepared a Solanum nigrum polyphenol extract (SNPE) from the SNE; the SNPE reduced hepatic lipid (oleic acid) accumulation. Therefore, SNE have the potential to alleviate NAFL-induced hepatitis, and polyphenolic compounds are the main components of SNE. Moreover, SNE can be used to develop health-food products for preventing NAFL disease.

Primary intrapelvic hemangiosarcoma in a dog.

A 12-year-old, spayed female Schnauzer presented with constipation. A mass was observed in the pelvic cavity, and metastasis was not identified. Mass resection was performed through celiotomy with pubic osteotomy, and hemangiosarcoma was diagnosed. At 10 weeks post-operatively, the patient died of multiple metastasis. Primary intrapelvic hemangiosarcoma is rare in dogs.

Pleiotropic effects of acarbose on atherosclerosis development in rabbits are mediated via upregulating AMPK signals.

Acarbose, an α-glucosidase inhibitor, is reported to reduce the incidence of silent myocardial infarction and slow the progression of intima-media thickening in patients with glucose intolerance. Here we investigate other impacts of acarbose on atherosclerosis development and the underlying mechanisms of atherosclerosis initiation and progression in vivo and in vitro. Rabbits fed a high cholesterol diet (HCD) were treated with acarbose (2.5-5.0 mg kg-1). Immunohistochemistry was used to assess the expression of inducible nitric oxide synthase (iNOS), Ras, proliferating cell nuclear antigen (PCNA), IL-6, ß-galactosidase, and p-AMPK in atherosclerotic lesions. Treatment with acarbose in HCD-fed rabbits was found to significantly reduce the severity of aortic atheroma and neointimal expression of α-actin, PCNA, IL-6, TNF-α, Ras, and ß-galactosidase; to significantly increase expression of iNOS and p-AMPK, but not to affect serum levels of glucose, total cholesterol, and LDL. Western blot analysis showed acarbose dose-dependently decreased ß-galactosidase and Ras expression and increased p-AMPK expression in TNF-α-treated A7r5 cells. In addition, acarbose restored p-AMPK and iNOS levels in AMPK inhibitor- and iNOS inhibitor-treated A7r5 cells, respectively. In conclusion, acarbose can pleiotropically inhibit rabbit atherosclerosis by reducing inflammation, senescence, and VSMCs proliferation/migration via upregulating AMPK signals.

Expression of neurotrophic factors in injured spinal cord after transplantation of human-umbilical cord blood stem cells in rats.

We induced percutaneous spinal cord injuries (SCI) using a balloon catheter in 45 rats and transplanted human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) at the injury site. Locomotor function was significantly improved in hUCB-MSCs transplanted groups. Quantitative ELISA of extract from entire injured spinal cord showed increased expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin-3 (NT-3). Our results show that treatment of SCI with hUCB-MSCs can improve locomotor functions, and suggest that increased levels of BDNF, NGF and NT-3 in the injured spinal cord were the main therapeutic effect.

Abnormal changes in both mandibular salivary glands in a dog: Non-mineral radiopaque sialoliths.

A 10-year-old Maltese dog was presented with a firm mass on the left side of his neck. Physical examination confirmed a firm mass in the left and a submandibular swelling in the right cervical region. Sialolithiasis and associated sialocele in both mandibular salivary glands were suspected and bilateral sialoadenectomy was performed. The stones were identified as non-mineral sialoliths.

Changements anormaux dans les deux glandes salivaires mandibulaires chez un chien : sialolithes radiopaques non minéraux. Un chien Maltais âgé de 10 ans a été présenté avec une masse ferme du côté droit du cou. L'examen physique a confirmé une masse ferme dans l'enflure gauche et sous-mandibulaire dans la région cervicale droite. La sialolithiase et une sialocèle connexe dans les deux glandes salivaires mandibulaires ont été suspectées et une sialoadénectomie bilatérale a été réalisée. Les pierres ont été identifiées comme des sialolithes non minéraux.(Traduit par Isabelle Vallières).

Safety and immunomodulatory effects of allogeneic canine adipose-derived mesenchymal stromal cells transplanted into the region of the lacrimal gland, the gland of the third eyelid and the knee joint.

BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) have been extensively studied as a cellular therapeutic for various pathologic conditions. However, there remains a paucity of data regarding regional and systemic safety of MSC transplantations, particularly with multiple deliveries of allogeneic cells. The purpose of this study was to investigate the safety and systemic immunomodulatory effects of repeated local delivery of allogeneic MSCs into the region of the lacrimal gland, the gland of the third eyelid and the knee joint in dogs. METHODS: Allogeneic adipose tissue-derived canine MSCs were delivered to the regions of the lacrimal gland and the third eyelid gland as well as in the knee joints of six healthy laboratory beagles as follows: six times with 1-week intervals for delivery to the lacrimal gland and the third eyelid gland regions and three to four times with 1- to 2-week intervals for intra-articular transplantations. Dogs were sequentially evaluated by clinical examination. At the conclusion of the study, dogs were humanely euthanized, and a complete gross and histopathologic examination of all organ systems was performed. Mixed leukocyte reactions were also performed before the first transplantation and after the final transplantation. RESULTS: Clinical and pathologic examinations found no severe consequences after repeated MSC transplantations. Results of mixed leukocyte reactions demonstrated suppression of T-cell proliferation after MSC transplantations. CONCLUSIONS: This is the first study to demonstrate regional and systemic safety and systemic immunomodulatory effects of repeated local delivery of allogeneic MSCs in vivo.

Mobilization of endogenous stem cell populations enhances fracture healing in a murine femoral fracture model.

BACKGROUND AIMS: Delivery of bone marrow-derived stem and progenitor cells to the site of injury is an effective strategy to enhance bone healing. An alternate approach is to mobilize endogenous, heterogeneous stem cells that will home to the site of injury. AMD3100 is an antagonist of the chemokine receptor 4 (CXCR4) that rapidly mobilizes stem cell populations into peripheral blood. Our hypothesis was that increasing circulating numbers of stem and progenitor cells using AMD3100 will improve bone fracture healing. METHODS: A transverse femoral fracture was induced in C57BL/6 mice, after which they were subcutaneously injected for 3 d with AMD3100 or saline control. Mesenchymal stromal cells, hematopoietic stem and progenitor cells and endothelial progenitor cells in the peripheral blood and bone marrow were evaluated by means of flow cytometry, automated hematology analysis and cell culture 24 h after injection and/or fracture. Healing was assessed up to 84 d after fracture by histomorphometry and micro-computed tomography. RESULTS: AMD3100 injection resulted in higher numbers of circulating mesenchymal stromal cells, hematopoietic stem cells and endothelial progenitor cells. Micro-computed tomography data demonstrated that the fracture callus was significantly larger compared with the saline controls at day 21 and significantly smaller (remodeled) at day 84. AMD3100-treated mice have a significantly higher bone mineral density than do saline-treated counterparts at day 84. CONCLUSIONS: Our data demonstrate that early cell mobilization had significant positive effects on healing throughout the regenerative process. Rapid mobilization of endogenous stem cells could provide an effective alternative strategy to cell transplantation for enhancing tissue regeneration.

Improved rat spinal cord injury model using spinal cord compression by percutaneous method.

Here, percutaneous spinal cord injury (SCI) methods using a balloon catheter in adult rats are described. A balloon catheter was inserted into the epidural space through the lumbosacral junction and then inflated between T9-T10 for 10 min under fluoroscopic guidance. Animals were divided into three groups with respect to inflation volume: 20 µL (n = 18), 50 µL (n = 18) and control (Fogarty catheter inserted but not inflated; n = 10). Neurological assessments were then made based on BBB score, magnetic resonance imaging and histopathology. Both inflation volumes produced complete paralysis. Gradual recovery of motor function occurred when 20 µL was used, but not after 50 µL was applied. In the 50 µL group, all gray and white matter was lost from the center of the lesion. In addition, supramaximal damage was noted, which likely prevented spontaneous recovery. This percutaneous spinal cord compression injury model is simple, rapid with high reproducibility and the potential to serve as a useful tool for investigation of pathophysiology and possible protective treatments of SCI in vivo.

Percutaneous transplantation of human umbilical cord-derived mesenchymal stem cells in a dog suspected to have fibrocartilaginous embolic myelopathy.

The use of human umbilical cord blood-derived mesenchymal stem cells for cell transplantation therapy holds great promise for repairing spinal cord injury. Here we report the first clinical trial transplantation of human umbilical cord (hUCB)-derived mesenchymal stem cells (MSCs) into the spinal cord of a dog suspected to have fibrocartilaginous embolic myelopathy (FCEM) and that experienced a loss of deep pain sensation. Locomotor functions improved following transplantation in a dog. Based on our findings, we suggest that transplantation of hUCB-derived MSCs will have beneficial therapeutic effects on FCEM patients lacking deep pain sensation.

Mulberry anthocyanins inhibit oleic acid induced lipid accumulation by reduction of lipogenesis and promotion of hepatic lipid clearance.

Mulberry (Morus alba L.) has been considered to possess different benefits such as protecting liver; improving fever, urine excretion disorder, hypertension, and diabetic syndrome; and preventing cardiovascular diseases. Recently, mounting evidence has shown that mulberry anthocyanin extract (MAE) is beneficial to hyperlipidemia; however, the mechanisms remain unclear. The present study was aimed to investigate the protective effects of MAE on hepatocyte cultured with high fatty acid and the underlying mechanisms. By using human hepatoma cell HepG2 as cell model, the results showed that MAE suppressed fatty acid synthesis and enhanced fatty acid oxidation, contributing to amelioration of lipid accumulation induced by oleic acid (OA). Moreover, MAE also inhibited acetyl coenzyme A carboxylase (ACC) activities by stimulating adenosine monophosphate-activated protein kinase (AMPK). MAE attenuated the expression of sterol regulatory element-binding protein-1 (SREBP-1) and its target molecules, such as fatty acid synthase (FAS). Similar results were also found in the expressions of enzymes involved in triglyceride and cholesterol biosyntheses including glycerol-3-phosphate acyltransferase (GPAT), 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCoR), adipocyte-specific fatty acid binding protein (A-FABP), and SREBP-2. In contrast, the lipolytic enzyme expressions of peroxisome proliferator activated receptor α (PPARα) and carnitinepalmitol- transferase-1 (CPT1) were increased. This study suggests the hypolipidemic effects of MAE occur via phosphorylation of AMPK and inhibition of lipid biosynthesis and stimulation of lipolysis. Therefore, the mulberry anthocyanins may actively prevent nonalcoholic fatty liver disease.

Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats.

We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm(2) section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals.

Long-term administration of AMD3100, an antagonist of SDF-1/CXCR4 signaling, alters fracture repair.

Fracture healing involves rapid stem and progenitor cell migration, homing, and differentiation. SDF-1 (CXCL12) is considered a master regulator of CXCR4-positive stem and progenitor cell trafficking to sites of ischemic (hypoxic) injury and regulates their subsequent differentiation into mature reparative cells. In this study, we investigated the role of SDF-1/CXCR4 signaling in fracture healing where vascular disruption results in hypoxia and SDF-1 expression. Mice were injected with AMD3100, a CXCR4 antagonist, or vehicle twice daily until euthanasia with the intent to impair stem cell homing to the fracture site and/or their differentiation. Fracture healing was evaluated using micro-computed tomography, histology, quantitative PCR, and mechanical testing. AMD3100 administration resulted in a significantly reduced hyaline cartilage volume (day 14), callus volume (day 42) and mineralized bone volume (day 42) and reduced expression of genes associated with endochondral ossification including collagen Type 1 alpha 1, collagen Type 2 alpha 1, vascular endothelial growth factor, Annexin A5, nitric oxide synthase 2, and mechanistic target of rapamycin. Our data suggest that the SDF-1/CXCR4 signaling plays a central role in bone healing possibly by regulating the recruitment and/or differentiation of stem and progenitor cells.

Anterior cruciate ligament reconstruction in a rabbit model using canine small intestinal submucosa and autologous platelet-rich plasma.

BACKGROUND: The bone-ligament interface is the main point of failure after anterior cruciate ligament reconstruction. Synthetic ligament materials have problems such as a greater failure rate of the bone-ligament insertion than autografts. Small intestinal submucosa (SIS) is a biologic scaffold that has been used to repair musculoskeletal tissue and has been shown to promote cell migration and enhance collagen fiber regeneration. Autologous platelet-rich plasma (PRP) has also been investigated as a potential promoter of tendon healing. We investigated SIS and PRP as biomaterials that might strengthen the bone-tunnel interface and improve tendon structure formation. METHODS: Anterior cruciate ligament grafts were formed of braid-twist canine SIS. These canine SIS ligament grafts were used for anterior cruciate ligament reconstruction in 20 New Zealand white rabbits. The rabbits were divided into 2 treatment groups. In 1 group (SIS group; n = 10), we only implanted the canine SIS grafts. In the second group (PRP group; n = 10), we applied autologous PRP to the surgical area after implantation of canine SIS grafts. We determined the cytokine level of the autologous PRP using a transforming growth factor-ß1 enzyme-linked immunosorbent assay kit. At 1 and 4 wk after surgery, magnetic resonance imaging was performed to evaluate the grafts. The femur-graft-tibia complex was assessed histologically and biomechanically at 8 wk after surgery. RESULTS: At 1 wk after surgery, the magnetic resonance imaging scans of the PRP group showed high signal-intensity lesions. In biomechanical tests, the SIS group had a significantly greater maximum load, maximum stress, and ultimate load and strain than the PRP group. The histologic findings of the PRP group revealed a greater cellular response, fibrotic tissue regeneration around the graft, broad chondrocyte cell infiltration, and collagen fibers that were loosely attached to the bone. CONCLUSIONS: The PRP group had significantly lower tension load values than the SIS group, and there was greater cellular response in a broad area around the grafts of the rabbits in the PRP group compared with those in the SIS group. The early inflammatory responses around the canine SIS grafts in the PRP group and the altered cytokine or growth factor concentration in the intra-articular capsule of the rabbits in PRP group might explain their relatively low tensile strength results.