Durable engraftment of genetically modified FVIII-secreting autologous bone marrow stromal cells in the intramedullary microenvironment.

Genetically modified FVIII-expressing autologous bone marrow-derived mesenchymal stromal cells (BMSCs) could cure haemophilia A. However, culture-expanded BMSCs engraft poorly in extramedullary sites. Here, we compared the intramedullary cavity, skeletal muscle, subcutaneous tissue and systemic circulation as tissue microenvironments that could support durable engraftment of FVIII-secreting BMSC in vivo. A zinc finger nuclease integrated human FVIII transgene into PPP1R12C (intron 1) of culture-expanded primary canine BMSCs. FVIII-secretory capacity of implanted BMSCs in each dog was expressed as an individualized therapy index (number of viable BMSCs implanted × FVIII activity secreted/million BMSCs/24 hours). Plasma samples before and after implantation were assayed for transgenic FVIII protein using an anti-human FVIII antibody having negligible cross-reactivity with canine FVIII. Plasma transgenic FVIII persisted for at least 48 weeks after implantation in the intramedullary cavity. Transgenic FVIII protein levels were low after intramuscular implantation and undetectable after both intravenous infusion and subcutaneous implantation. All plasma samples were negative for anti-human FVIII antibodies. Plasma concentrations and durability of transgenic FVIII secretion showed no correlation with the therapy index. Thus, the implantation site microenvironment is crucial. The intramedullary microenvironment, but not extramedullary tissues, supported durable engraftment of genetically modified autologous FVIII-secreting BMSCs.

A Dual Tracer 18F-FCH/18F-FDG PET Imaging of an Orthotopic Brain Tumor Xenograft Model.

Early diagnosis of low grade glioma has been a challenge to clinicians. Positron Emission Tomography (PET) using 18F-FDG as a radio-tracer has limited utility in this area because of the high background in normal brain tissue. Other radiotracers such as 18F-Fluorocholine (18F-FCH) could provide better contrast between tumor and normal brain tissue but with high incidence of false positives. In this study, the potential application of a dual tracer 18F-FCH/18F-FDG-PET is investigated in order to improve the sensitivity of PET imaging for low grade glioma diagnosis based on a mouse orthotopic xenograft model. BALB/c nude mice with and without orthotopic glioma xenografts from U87 MG-luc2 glioma cell line are used for the study. The animals are subjected to 18F-FCH and 18F-FDG PET imaging, and images acquired from two separate scans are superimposed for analysis. The 18F-FCH counts are subtracted from the merged images to identify the tumor. Micro-CT, bioluminescence imaging (BLI), histology and measurement of the tumor diameter are also conducted for comparison. Results show that there is a significant contrast in 18F-FCH uptake between tumor and normal brain tissue (2.65 ± 0.98), but with a high false positive rate of 28.6%. The difficulty of identifying the tumor by 18F-FDG only is also proved in this study. All the tumors can be detected based on the dual tracer technique of 18F-FCH/18F-FDG-PET imaging in this study, while the false-positive caused by 18F-FCH can be eliminated. Dual tracer 18F-FCH/18F-FDG PET imaging has the potential to improve the visualization of low grade glioma. 18F-FCH delineates tumor areas and the tumor can be identified by subtracting the 18F-FCH counts. The sensitivity was over 95%. Further studies are required to evaluate the possibility of applying this technique in clinical trials.

Preclinical Evaluation of Tegaderm™ Supported Nanofibrous Wound Matrix Dressing on Porcine Wound Healing Model.

Objective: Nanofibers for tissue scaffolding and wound dressings hold great potential in realizing enhanced healing of wounds in comparison with conventional counterparts. Previously, we demonstrated good fibroblast adherence and growth on a newly developed scaffold, Tegaderm™-Nanofiber (TG-NF), made from poly ɛ-caprolactone (PCL)/gelatin nanofibers electrospun onto Tegaderm (TG). The purpose of this study is to evaluate the performance and safety of TG-NF dressings in partial-thickness wound in a pig healing model. Approach: To evaluate the rate of reepithelialization, control TG, human dermal fibroblast-seeded TG-NF(+) and -unseeded TG-NF(-) were randomly dressed onto 80 partial-thickness burns created on four female and four male pigs. Wound inspections and dressings were done after burns on day 7, 14, 21, and 28. On day 28, full-thickness biopsies were taken for histopathological evaluation by Masson-Trichrome staining for collagen and hematoxylin-eosin staining for cell counting. Results: No infection and severe inflammation were recorded. Wounds treated with TG-NF(+) reepithelialized significantly faster than TG-NF(-) and control. Wound site inflammatory responses to study groups were similar as total cell counts on granulation tissues show no significant differences. Most of the wounds completely reepithelialized by day 28, except for two wounds in control and TG-NF(-). A higher collagen coverage was also recorded in the granulation tissues treated with TG-NF(+). Innovation and Conclusion: With better reepithelialization achieved by TG-NF(+) and similar rates of wound closure by TG-NF(-) and control, and the absence of elevated inflammatory responses to TG-NF constructs, TG-NF constructs are safe and demonstrated good healing potentials that are comparable to Tegaderm.

Characterization of Insulin-Secreting Porcine Bone Marrow Stromal Cells Ex Vivo and Autologous Cell Therapy In Vivo.

Cell therapy could potentially meet the need for pancreas and islet transplantations in diabetes mellitus that far exceeds the number of available donors. Bone marrow stromal cells are widely used in clinical trials mainly for their immunomodulatory effects with a record of safety. However, less focus has been paid to developing these cells for insulin secretion by transfection. Although murine models of diabetes have been extensively used in gene and cell therapy research, few studies have shown efficacy in large preclinical animal models. Here we report optimized conditions for ex vivo expansion and characterization of porcine bone marrow stromal cells and their permissive expression of a transfected insulin gene. Our data show that these cells resemble human bone marrow stromal cells in surface antigen expression, are homogeneous, and can be reproducibly isolated from outbred Yorkshire-Landrace pigs. Porcine bone marrow stromal cells were efficiently expanded in vitro to >10(10) cells from 20 ml of bone marrow and remained karyotypically normal during expansion. These cells were electroporated with an insulin expression plasmid vector with high efficiency and viability, and secreted human insulin and C-peptide indicating appropriate processing of proinsulin. We showed that autologous insulin-secreting bone marrow stromal cells implanted and engrafted in the liver of a streptozotocin-diabetic pig that modeled type 1 diabetes resulted in partial, but significant, improvement in hyperglycemia that could not be ascribed to regeneration of endogenous ß-cells. Glucose-stimulated insulin secretion in vivo from implanted cells in the treated pig was documented by a rise in serum human C-peptide levels during intravenous glucose tolerance tests. Compared to a sham-treated control pig, this resulted in significantly reduced fasting hyperglycemia, a slower rise in serum fructosamine, and prevented weight loss. Taken together, this study suggests that bone marrow stromal cells merit further development as autologous cell therapy for diabetes.

The use of submicron/nanoscale PLGA implants to deliver paclitaxel with enhanced pharmacokinetics and therapeutic efficacy in intracranial glioblastoma in mice.

Pharmacokinetics and therapeutic efficacy of submicron/nanoscale, intracranial implants were evaluated for treating malignant glioblastoma in mice. 9.1% (w/w) paclitaxel-loaded polylactide-co-glycolide (PLGA) nanofiber discs (F3) were fabricated and characterized for morphology and size distribution. Along with F3, three other formulations, 9.1% (w/w) paclitaxel-loaded PLGA submicron-fiber discs (F2), 16.7% (w/w) paclitaxel-loaded PLGA microspheres entrapped in hydrogel matrices (H80 and M80) were intracranially implanted in BALB/c mice and the coronal brain sections were analyzed for bio-distribution of paclitaxel on 14, 28 and 42 days post-implantation. BALB/c nude mice with intracranial human glioblastoma (U87 MG-luc2) were used in the therapeutic efficacy study. Animals were randomized to intracranial implantation of F3 and H80 with paclitaxel dose of 10mg/kg, placebo F3, placebo H80, weekly intratumoral injection of Taxol (10mg/kg) or no treatment and the treatment response was analyzed by bioluminescence imaging and histological (H&E, Ki-67) examinations. Enhanced, therapeutic paclitaxel penetration (approximately 1 microm) in the mouse brain up to 5mm from the implant site even after 42 days post-implantation from F3 and H80 was confirmed and deduced to be diffusion/elimination controlled. F3 and H80 demonstrated significant (approximately 30 fold) tumor inhibition and significantly low tumor proliferation index after 41 days of treatment in comparison to sham and placebo controls. The submicron/nanoscale implants are able to demonstrate optimal paclitaxel pharmacokinetics in the brain/tumor with significant tumor inhibition in a glioblastoma xenograft model in mice and hence could be potentially useful to treat highly recurrent GBM.

Identification of proteins differentially expressed between capillary endothelial cells of hepatocellular carcinoma and normal liver in an orthotopic rat tumor model using 2-D DIGE.

Hepatocellular carcinoma (HCC) is one of the deadliest cancers with few treatment options. It is a hypervascular tumor in which angiogenesis plays a critical role in its progression. Tumor capillary endothelial cells (TECs) in HCC are known to originate from liver sinusoid endothelial cells, which then go through a capillarization process to become morphologically as well as functionally different TECs. In this work, we investigated proteins differentially expressed between freshly isolated TECs and sinusoid endothelial cells from well-formed rat HCC using 2-D DIGE coupled with MALDI-TOF/TOF MS. Thirty-eight unique proteins were identified to be differentially expressed more than twofold between the two endothelial cell types. Amongst the differentially expressed proteins, two novel endothelial markers, EH domain-containing protein 3 and galectin-3, were confirmed by Western blot and immunohistochemistry in both rat and human HCC samples. We showed that EH domain-containing protein 3 is significantly down-regulated in TECs, but galectin-3 is up-regulated. We propose possible roles of these two proteins in tumor vessel development in HCC.

Hydrogel matrix entrapping PLGA-paclitaxel microspheres: drug delivery with near zero-order release and implantability advantages for malignant brain tumour chemotherapy.

PURPOSE: To develop paclitaxel-delivering PLGA microspheres entrapped in a gel matrix with sustained drug release properties and implantability advantages for local glioma chemotherapy. METHODS: Paclitaxel-loaded PLGA microspheres were fabricated using electrohydrodynamic atomization and entrapped by electrospray and gelation. The physicochemical characterizations were performed using scanning electron microscopy and differential scanning calorimetry. The influence of various parameters on the disintegration time was investigated. In vitro release of paclitaxel was quantified using high performance liquid chromatography. Cytotoxicity of the formulations was assessed by the quantification of IC(50) and caspase-3 activity against C6 glioma cells in vitro. The formulations were tested against a subcutaneous C6 glioma tumour in mice. RESULTS: Highly monodisperse gel beads containing a uniform microsphere distribution were obtained. Gelation using Ca(2+) ions ensured entrapment of microspheres with high loading efficiency. With an increase in the gelation time, gelling bath concentration and decrease in microsphere loading, it was more difficult to disintegrate the beads and release the microspheres. The formulations demonstrated sustained drug release for more than 60 days at a near-constant rate and a low initial burst. Cell culture studies proved the cytotoxicity against C6 glioma and improved performance in comparison to Taxol. The formulations could reduce subcutaneous tumour volume to a greater extent compared to Taxol and the control. CONCLUSIONS: Paclitaxel-loaded PLGA microspheres entrapped in an alginate gel matrix could be potential local chemotherapy implants to treat malignant glioma with critical advantages of implantability and sustained drug release with low initial burst.

Effective inhibition of xenografts of hepatocellular carcinoma (HepG2) by rapamycin and bevacizumab in an intrahepatic model.

PURPOSE: Hepatocellular carcinoma (HCC) displays a characteristic hypervascularity and depends on angiogenesis for tumor growth, which thus provides a potential target for therapeutic approaches to HCC. In this study, through the use of combined micro-positron emission tomography (PET)/computed tomography (CT), we investigate if such a combined targeting of vascular endothelial growth factor (VEGF) activity and expression might retard HCC growth in an orthotopic intrahepatic xenograft model. PROCEDURES: Xenograft models were created by intraportal vein injection of HepG2 cell suspensions in severe combined immunodeficient mice. The mice were then treated with (1) rapamycin (RAPA), a mammalian target of rapamycin pathway inhibitor; (2) bevazicumab (BEV), a VEGF monoclonal antibody; and (3) a RAPA/BEV combination. RESULTS: Assessment of HCC progression using CT with Omnipaque and PET with 2-deoxy-2-(F-18)-fluoro-D: -glucose showed that mice treated with RAPA/BEV had the lowest standardized uptake values (SUVs). At week 2, mice treated with RAPA/BEV, RAPA, and BEV all showed a marked decrease in the SUV(max) readings with the greatest drop being observed in the RAPA/BEV group (1.33 + 0.26, 1.81 + 0.2, 2.05 + 0.4 vs. vehicle control 2.11 + 0.53). CONCLUSIONS: Our results, supported by micro-PET/CT, suggest that RAPA/BEV represents a potential novel antiangiogenic therapy for the treatment of HCC.

Platelet-rich plasma has no effect on increasing free fat graft survival in the nude mouse.

BACKGROUND: Free fat grafts have an unpredictable survival rate, which may be dependent on host bed vascularity. Therefore, the authors hypothesized that the presence of growth factors in platelet-rich plasma (PRP), may enhance free fat graft survival. METHODS: Free fat grafts and autologous PRP were harvested from a healthy female and processed using the Coleman technique and the Medtronic Magellan system respectively. The experiment comprised two groups of 12 nude mice each with injection of free fat grafts into the scalp. The experimental group comprised the combination of 0.8 ml of free fat graft and 0.2 ml of PRP. The control group comprised the combination of 0.8 ml of free fat graft and 0.2 ml of normal saline. The mice were euthanized after 16 weeks and the fat grafts explanted and measured for weight and volume. Histology was performed with Oil Red O stain. Statistical analysis of the weight and volume in between groups was performed using the independent samples T-test (SPSS v11). The Mann-Whitney test was used to compare the ranking of six histological parameters between the two groups. RESULTS: The mean weight and volume for the experimental arm were 0.503 g and 0.545 ml respectively. The mean weight and volume for the control arm were 0.500 g and 0.541 ml respectively. The weight, volume and histological parameters between the two groups were not statistically significant. A mouse from each group died of unknown causes. CONCLUSION: PRP did not enhance free fat graft survival in the nude mouse.

Nonvirally modified autologous primary hepatocytes correct diabetes and prevent target organ injury in a large preclinical model.

BACKGROUND: Current gene- and cell-based therapies have significant limitations which impede widespread clinical application. Taking diabetes mellitus as a paradigm, we have sought to overcome these limitations by ex vivo electrotransfer of a nonviral insulin expression vector into primary hepatocytes followed by immediate autologous reimplantation in a preclinical model of diabetes. METHODS AND RESULTS: In a single 3-hour procedure, hepatocytes were isolated from a surgically resected liver wedge, electroporated with an insulin expression plasmid ex vivo and reimplanted intraparenchymally under ultrasonic guidance into the liver in each of 10 streptozotocin-induced diabetic Yorkshire pigs. The vector was comprised of a bifunctional, glucose-responsive promoter linked to human insulin cDNA. Ambient glucose concentrations appropriately altered human insulin mRNA expression and C-peptide secretion within minutes in vitro and in vivo. Treated swine showed correction of hyperglycemia, glucose intolerance, dyslipidemia and other metabolic abnormalities for > or = 47 weeks. Metabolic correction correlated significantly with the number of hepatocytes implanted. Importantly, we observed no hypoglycemia even under fasting conditions. Direct intrahepatic implantation of hepatocytes did not alter biochemical indices of liver function or induce abnormal hepatic lobular architecture. About 70% of implanted hepatocytes functionally engrafted, appeared histologically normal, retained vector DNA and expressed human insulin for > or = 47 weeks. Based on structural tissue analyses and transcriptome data, we showed that early correction of diabetes attenuated and even prevented pathological changes in the eye, kidney, liver and aorta. CONCLUSIONS: We demonstrate that autologous hepatocytes can be efficiently, simply and safely modified by electroporation of a nonviral vector to express, process and secrete insulin durably. This strategy, which achieved significant and sustained therapeutic efficacy in a large preclinical model without adverse effects, warrants consideration for clinical development especially as it could have broader future applications for the treatment of other acquired and inherited diseases for which systemic reconstitution of a specific protein deficiency is critical.

Long-term changes in hepatobiliary physiology after Roux-en-Y hepaticojejunostomy.

Hepaticojejunostomy (HJ) is a common operation used to by-pass extrahepatic biliary obstructions and to establish biliary-enteric continuity after resections for benign and malignant diseases. Little is known about the effect of this procedure on hepatobiliary physiology. The aim of the present study was to investigate in a swine model the changes in biliary dynamics, bile composition, and hepatic histology induced by Roux-Y HJ. Twenty-four swine (57 (47 to 76) kg) underwent cholecystectomy, with HJ (Group I; n = 12) or without any biliodigestive anastomosis (Group II, n = 12), and were followed up for 6 or 12 mo by repeated weight scaling, blood, serum, and bile analysis, (99m)Technetium (Tc), diethyliminodiacetic acid (HIDA) dynamic biligraphy, and histological analysis. During follow-up, HJ was associated with less weight gain, colonization of the bile duct with aerobic bacteria Escherichia coli dominating (in 75% of the animals), a shortened hilum-intestine transit time but reduced liver clearance in dynamic biligraphy, and fibrous periportal changes in liver histology (in 50% of the animals). We conclude that during 1 y follow-up HJ with no anastomotic stricture formation is associated with improved extrahepatic bile drainage, but with ascending contamination of bile ducts with bacteria, which might be involved with the fibrous periportal changes in the liver resulting in diminished excretion of Tc-HIDA from the hepatocytes into the bile. The clinical significance of these changes, and the reduced weight gain observed is a topic of further investigations.

A novel biodegradable biliary stent in the normal duct hepaticojejunal anastomosis: an 18-month follow-up in a large animal model.

Creating a well-functioning hepaticojejunostomy (HJ) anastomosis with nondilated bile ducts remains a challenge. Our aim was to study the use in a large animal model of a novel, braided polylactide barium sulfate biodegradable biliary stent (BDBS) without external connection and with no need for later removal. Fifty swine were randomly operated on for Roux-Y HJ with or without BDBS in the anastomosis, and followed up (dynamic biligraphy, x-ray, serum determinations, anastomosis inner diameter, and histology) for 1.5, 3, 6, 12, and 18 months. During the follow-up, one nonstented animal died because of anastomotic leakage. In x-ray BDBS was seen in place until 1.5 months in all of the stented animals. In the nonstented animals HJ anastomosis inner diameter was decreased at 18 months [6.3 (5.0-7.0) mm vs 7.4 (7.0-9.0) mm, p = 0.05] and liver clearance reduced at 12 and 18 months compared to stented animals. Serum liver values and liver and bile duct histology did not differ between the groups. We conclude that this novel BDBS is easy to insert into the HJ anastomosis with nondilated ducts. It is nontoxic, dissolves safely, and may be associated with a larger and better draining anastomosis at 18-month follow-up. These results encourage us to proceed to clinical studies.

Effects of genetic immunization of Swiss outbred mice with human thyroid stimulating hormone receptor cDNA plasmids harboring gain-of-function mutations.

Animal models of Graves' disease have been generated in recent years with various vaccination protocols using wild-type TSH receptor. In this study, we report the findings of genetic immunization of Swiss outbred mice with three different mutated human TSH receptor plasmids, each containing one constitutive activating mutation located at the ectodomain (S281N), exoloop (I486F), and transmembrane segment (D633H) respectively. Although the overall rate of thyrotoxicosis in the mice was < 10%, anti-TSH receptor antibodies could be detected in many animals by flow cytometry, radioreceptor assay, and functional bioassays using recombinant human TSH receptor. Mice injected with plasmids harboring activated mutants (S281N and D633H) showed production of predominantly stimulating antibodies, whilst those treated with wild-type receptor plasmids generated mainly blocking sera. Most of these antibodies displaced radiolabeled bovine TSH, and their epitopes, independent of functional characteristics, were mapped to the first 271 amino acids of the TSH receptor. This supports recent findings that binding of stimulatory or blocking antibodies lie in close proximity within the leucine-rich repeat region.

Plasma free hemoglobin: a novel diagnostic test for assessment of the depth of burn injury.

BACKGROUND: Accurate determination of the depth of burn injury is difficult, even for experienced surgeons. The authors hypothesized that the level of plasma free hemoglobin following burn injury is correlated to the depth of burn injury, and they evaluated this hypothesis in a murine model. METHODS: Full-thickness and partial-thickness burn injuries of varying sizes were inflicted on 38 and 36 male Wistar rats, respectively. Blood specimens were taken at 0, 15, 30, 45, and 60 minutes after burn injury, and the levels of plasma free hemoglobin were determined spectrophotometrically. RESULTS: Full-thickness burns cause two times more hemolysis than partial-thickness burns (p < 0.05). A linear correlation was demonstrated between plasma free hemoglobin levels and total body surface area burned in both the full-thickness (r = 0.91, p < 0.001) and partial-thickness burn groups (r = 0.94, p < 0.001). The correlation between the quantity of hemolysis and the total body surface area burned was strongest at 15 minutes after the onset of burn injury. The levels of free hemoglobin peaked rapidly between 15 and 30 minutes after thermal injury and declined thereafter. CONCLUSIONS: The authors' data suggest that the level of plasma free hemoglobin after burn injury is related to the size and depth of burn injury. This test can potentially be a valuable diagnostic adjunct in the assessment of burns.