Expandable Sendai-Virus-Reprogrammed Human iPSC-Neuronal Precursors: In Vivo Post-Grafting Safety Characterization in Rats and Adult Pig.

One of the challenges in clinical translation of cell-replacement therapies is the definition of optimal cell generation and storage/recovery protocols which would permit a rapid preparation of cell-treatment products for patient administration. Besides, the availability of injection devices that are simple to use is critical for potential future dissemination of any spinally targeted cell-replacement therapy into general medical practice. Here, we compared the engraftment properties of established human-induced pluripotent stem cells (hiPSCs)-derived neural precursor cell (NPCs) line once cells were harvested fresh from the cell culture or previously frozen and then grafted into striata or spinal cord of the immunodeficient rat. A newly developed human spinal injection device equipped with a spinal cord pulsation-cancelation magnetic needle was also tested for its safety in an adult immunosuppressed pig. Previously frozen NPCs showed similar post-grafting survival and differentiation profile as was seen for freshly harvested cells. Testing of human injection device showed acceptable safety with no detectable surgical procedure or spinal NPCs injection-related side effects.

Derivation of Sendai-Virus-Reprogrammed Human iPSCs-Neuronal Precursors: In Vitro and In Vivo Post-grafting Safety Characterization.

The critical requirements in developing clinical-grade human-induced pluripotent stem cells-derived neural precursors (hiPSCs-NPCs) are defined by expandability, genetic stability, predictable in vivo post-grafting differentiation, and acceptable safety profile. Here, we report on the use of manual-selection protocol for generating expandable and stable human NPCs from induced pluripotent stem cells. The hiPSCs were generated by the reprogramming of peripheral blood mononuclear cells with Sendai-virus (SeV) vector encoding Yamanaka factors. After induction of neural rosettes, morphologically defined NPC colonies were manually harvested, re-plated, and expanded for up to 20 passages. Established NPCs showed normal karyotype, expression of typical NPCs markers at the proliferative stage, and ability to generate functional, calcium oscillating GABAergic or glutamatergic neurons after in vitro differentiation. Grafted NPCs into the striatum or spinal cord of immunodeficient rats showed progressive maturation and expression of early and late human-specific neuronal and glial markers at 2 or 6 months post-grafting. No tumor formation was seen in NPCs-grafted brain or spinal cord samples. These data demonstrate the effective use of in vitro manual-selection protocol to generate safe and expandable NPCs from hiPSCs cells. This protocol has the potential to be used to generate GMP (Good Manufacturing Practice)-grade NPCs from hiPSCs for future clinical use.

In vitro modeling of amyotrophic lateral sclerosis with induced pluripotent stem cell technology-derived cell line ORIONi002-A.

We present here a new iPS cell line for modeling sporadic form of ALS. Cell line was generated by reprogramming skin fibroblasts isolated with explant culture technology from skin biopsy, donated by ALS patient. For reprogramming, polycistronic self-replicating RNA vector was used and derived iPS cells were characterized by immunocytochemistry and FACS (pluripotent factors expression), karyotyping, STR fingerprinting analysis and in vitro differentiation assay. New cell line showed normal (46, XY) karyotype and differentiated in vitro into cells from three germ layers. STR analysis proved the origin and originality of the cell line.

Precision spinal gene delivery-induced functional switch in nociceptive neurons reverses neuropathic pain.

Second-order spinal cord excitatory neurons play a key role in spinal processing and transmission of pain signals to the brain. Exogenously induced change in developmentally imprinted excitatory neurotransmitter phenotypes of these neurons to inhibitory has not yet been achieved. Here, we use a subpial dorsal horn-targeted delivery of AAV (adeno-associated virus) vector(s) encoding GABA (gamma-aminobutyric acid) synthesizing-releasing inhibitory machinery in mice with neuropathic pain. Treated animals showed a progressive and complete reversal of neuropathic pain (tactile and brush-evoked pain behavior) that persisted for a minimum of 2.5 months post-treatment. The mechanism of this treatment effect results from the switch of excitatory to preferential inhibitory neurotransmitter phenotype in dorsal horn nociceptive neurons and a resulting increase in inhibitory activity in regional spinal circuitry after peripheral nociceptive stimulation. No detectable side effects (e.g., sedation, motor weakness, loss of normal sensation) were seen between 2 and 13 months post-treatment in naive adult mice, pigs, and non-human primates. The use of this treatment approach may represent a potent and safe treatment modality in patients suffering from spinal cord or peripheral nerve injury-induced neuropathic pain.

Subretinal Implantation of Human Primary RPE Cells Cultured on Nanofibrous Membranes in Minipigs.

PURPOSE: The development of primary human retinal pigmented epithelium (hRPE) for clinical transplantation purposes on biodegradable scaffolds is indispensable. We hereby report the results of the subretinal implantation of hRPE cells on nanofibrous membranes in minipigs. METHODS: The hRPEs were collected from human cadaver donor eyes and cultivated on ultrathin nanofibrous carriers prepared via the electrospinning of poly(L-lactide-co-DL-lactide) (PDLLA). "Libechov" minipigs (12-36 months old) were used in the study, supported by preoperative tacrolimus immunosuppressive therapy. The subretinal implantation of the hRPE-nanofibrous carrier was conducted using general anesthesia via a custom-made injector during standard three-port 23-gauge vitrectomy, followed by silicone oil endotamponade. The observational period lasted 1, 2, 6 and 8 weeks, and included in vivo optical coherence tomography (OCT) of the retina, as well as post mortem immunohistochemistry using the following antibodies: HNAA and STEM121 (human cell markers); Bestrophin and CRALBP (hRPE cell markers); peanut agglutining (PNA) (cone photoreceptor marker); PKCα (rod bipolar marker); Vimentin, GFAP (macroglial markers); and Iba1 (microglial marker). RESULTS: The hRPEs assumed cobblestone morphology, persistent pigmentation and measurable trans-epithelial electrical resistance on the nanofibrous PDLLA carrier. The surgical delivery of the implants in the subretinal space of the immunosuppressed minipigs was successfully achieved and monitored by fundus imaging and OCT. The implanted hRPEs were positive for HNAA and STEM121 and were located between the minipig's neuroretina and RPE layers at week 2 post-implantation, which was gradually attenuated until week 8. The neuroretina over the implants showed rosette or hypertrophic reaction at week 6. The implanted cells expressed the typical RPE marker bestrophin throughout the whole observation period, and a gradual diminishing of the CRALBP expression in the area of implantation at week 8 post-implantation was observed. The transplanted hRPEs appeared not to form a confluent layer and were less capable of keeping the inner and outer retinal segments intact. The cone photoreceptors adjacent to the implant scaffold were unchanged initially, but underwent a gradual change in structure after hRPE implantation; the retina above and below the implant appeared relatively healthy. The glial reaction of the transplanted and host retina showed Vimentin and GFAP positivity from week 1 onward. Microglial activation appeared in the retinal area of the transplant early after the surgery, which seemed to move into the transplant area over time. CONCLUSIONS: The differentiated hRPEs can serve as an alternative cell source for RPE replacement in animal studies. These cells can be cultivated on nanofibrous PDLLA and implanted subretinally into minipigs using standard 23-gauge vitrectomy and implantation injector. The hRPE-laden scaffolds demonstrated relatively good incorporation into the host retina over an eight-week observation period, with some indication of a gliotic scar formation, and a likely neuroinflammatory response in the transplanted area despite the use of immunosuppression.

A novel postgraduate endoscopic course using a large animal model of secondary Crohn's disease stricture.

BACKGROUND: The increasing complexity of advanced endoscopic techniques places a high demand on the endoscopist's expertise. Thus, live porcine models have been more frequently used for training. We briefly describe a hands-on postgraduate endoscopic course regarding a novel method of treatment of anastomotic strictures in a porcine model. METHODS: The porcine model of Crohn's disease anastomotic stricture with two artificial side-to-side ileo-colonic anastomoses was used. Participants performed endoscopic stricturotomy under supervision at one of two equipped endoscopic stations. Available animals were endoscopically re-examined 3 months after the course. RESULTS: Twelve anastomoses were prepared for the course. Eleven circumferential stricturotomies together with horizontal cut and clip placement were conducted. All anastomoses were passable for the scope after the procedure, and no case of perforation or bleeding occurred. All anastomoses available for re-examination remained passable for the endoscope after 3 months. CONCLUSION: We successfully organised the first endoscopic hands-on course for the training of endoscopic stricturotomy on a large animal model.

Novel porcine model of Crohn's disease anastomotic stricture suitable for evaluation and training of advanced endoscopic techniques.

BACKGROUND AND AIMS: Currently, treatment options in postsurgical recurrence of stricturing Crohn's disease (CD) are limited. However, development of new invasive endoscopic techniques in clinical practice has safety constraints. The aim of this study was to create a large animal model of anastomotic stricture with CD properties to enable development of new techniques and training. METHODS: A side-to-side ileocolonic anastomosis was created in a modified Roux-en-Y manner with bowel continuity preserved. Two weeks after surgery, we began endoscopic submucosal injections of phenol/trinitrobenzenesulfonic acid solution. This solution was injected every 2 weeks in each quadrant of the anastomosis until development of a stricture. The anastomosis site was assessed endoscopically 2 weeks after the last application (baseline) and then every 2 months until month 6. Endoscopically nonpassable strictures were treated with balloon dilation, endoscopic stricturotomy, and stent placement to confirm the feasibility of such interventions. RESULTS: Nineteen minipigs were included with no postoperative adverse events. After a mean of 4.4 ± .7 injection sessions with 10.5 ± 3.0 mL of the solution, anastomotic strictures were created in 16 pigs (84.2%). Mean diameter of the strictures at baseline was 11.6 ± 2.2 mm. The strictures were inflamed, and the endoscope could not pass. Follow-up was successfully completed in 15 animals (79.0%) with the mean deviation from the initial diameter in every measurement of -.02 ± 2.26 mm (P = .963) and a mean final diameter of 11.7 ± 3.4 mm. The histopathologic evaluation revealed the presence of submucosal fibrosis, chronic inflammation, and microgranulomas. All strictures were amenable to endoscopic therapeutic interventions. CONCLUSIONS: We developed a novel, reproducible porcine model of anastomotic stricture with histologically verified changes mimicking CD and stable diameter for more than 6 months. It is suitable for further endoscopic interventions.

Stenting to prevent esophageal stricture after circumferential endoscopic submucosal dissection: an experimental study.

Background and study aims Circular ESD (CESD) is a treatment option for patients with extensive early esophageal cancer. Its major drawback is the development of a stricture. Stenting may represent an attractive prevention strategy. We designed an experimental study to assess the effect of stents covered with acellular biomatrix (AB) and a drug-eluting stent. Materials and methods Thirty-five 35 pigs underwent CESD and were randomized into six groups: G1 (control), G2 (SEMS), G3 (SEMS + AB), G4 (SEMS + AB + steroid-eluting layer), G5 (biodegradable stent [BD]), G6 (BD + AB). SEMS were placed alongside the post-CESD defect, fixed and removed after 21 days. The main outcomes were stricture development, severity, and histopathology. Results Pigs with BD stents (G5, 6) experienced severe inflammation and hypergranulation without biodegradation, therefore, these groups were closed prematurely. Significant strictures developed in 29 of 30 pigs (96.7 %). The most severe stricture developed in G2 and G4 (narrowest diameter (mm) 8.5 ±â€Š3, 3 (G2) and 8.6 ±â€Š2.1 (G4) vs. 17 ±â€Š7.3 (G1) and 13.5 ±â€Š8.3 (G3); P  < 0.01. Signs of re-epithelization were present in 67 % and 71 % in G1 and G2 and in 100 % in G3 and G4. The most robust re-epithelization layer was present in G4. The inflammation was the most severe in G1 (mean score 2.3) and least severe in G4 (0.4). Conclusions Stenting did not effectively prevent development of post-CESD esophageal stricture. SEMS with AB resulted in improved re-epithelization and decreased stricture severity. Steroid-eluting SEMS suppressed inflammation. BD stents seem inappropriate for this indication.

Generation of ORIONi001-A induced pluripotent stem cell line for in vitro modeling of sporadic form of amyotrophic lateral sclerosis.

We generated new in vitro model for sporadic form of amyotrophic lateral sclerosis by reprogramming isolated skin fibroblasts into iPSCs. Fibroblasts were reprogrammed with commercially available synthetic polycistronic, self-replicating RNA vector. As verified by FISH, an early passages of a new iPSC line showed mosaic karyotype (cells with normal and abnormal karyotype 46,XY,t(2;14)(q13;p12) were present), while late passages contained only cells with abnormal karyotype. New iPSCs differentiated into all three germ layers and formed a teratoma in nude mice. Our iPSC line represents a new model for therapy testing and drug development in the field of ALS research.

Spinal subpial delivery of AAV9 enables widespread gene silencing and blocks motoneuron degeneration in ALS.

Gene silencing with virally delivered shRNA represents a promising approach for treatment of inherited neurodegenerative disorders. In the present study we develop a subpial technique, which we show in adult animals successfully delivers adeno-associated virus (AAV) throughout the cervical, thoracic and lumbar spinal cord, as well as brain motor centers. One-time injection at cervical and lumbar levels just before disease onset in mice expressing a familial amyotrophic lateral sclerosis (ALS)-causing mutant SOD1 produces long-term suppression of motoneuron disease, including near-complete preservation of spinal α-motoneurons and muscle innervation. Treatment after disease onset potently blocks progression of disease and further α-motoneuron degeneration. A single subpial AAV9 injection in adult pigs or non-human primates using a newly designed device produces homogeneous delivery throughout the cervical spinal cord white and gray matter and brain motor centers. Thus, spinal subpial delivery in adult animals is highly effective for AAV-mediated gene delivery throughout the spinal cord and supraspinal motor centers.

Positive impact of dynamic seeding of mesenchymal stem cells on bone-like biodegradable scaffolds with increased content of calcium phosphate nanoparticles.

One of the main aims of bone tissue engineering, regenerative medicine and cell therapy is development of an optimal artificial environment (scaffold) that can trigger a favorable response within the host tissue, it is well colonized by resident cells of organism and ideally, it can be in vitro pre-colonized by cells of interest to intensify the process of tissue regeneration. The aim of this study was to develop an effective tool for regenerative medicine, which combines the optimal bone-like scaffold and colonization technique suitable for cell application. Accordingly, this study includes material (physical, chemical and structural) and in vitro biological evaluation of scaffolds prior to in vivo study. Thus, porosity, permeability or elasticity of two types of bone-like scaffolds differing in the ratio of collagen type I and natural calcium phosphate nanoparticles (bCaP) were determined, then analyzes of scaffold interaction with mesenchymal stem cells (MSCs) were performed. Simultaneously, dynamic seeding using a perfusion bioreactor followed by static cultivation was compared with standard static cultivation for the whole period of cultivation. In summary, cell colonization ability was estimated by determination of cell distribution within the scaffold (number, depth and homogeneity), matrix metalloproteinase activity and gene expression analysis of signaling molecules and differentiation markers. Results showed, the used dynamic colonization technique together with the newly-developed collagen-based scaffold with high content of bCaP to be an effective combined tool for producing bone grafts for bone implantology and regenerative medicine.

A scalable solution for isolating human multipotent clinical-grade neural stem cells from ES precursors.

BACKGROUND: A well-characterized method has not yet been established to reproducibly, efficiently, and safely isolate large numbers of clinical-grade multipotent human neural stem cells (hNSCs) from embryonic stem cells (hESCs). Consequently, the transplantation of neurogenic/gliogenic precursors into the CNS for the purpose of cell replacement or neuroprotection in humans with injury or disease has not achieved widespread testing and implementation. METHODS: Here, we establish an approach for the in vitro isolation of a highly expandable population of hNSCs using the manual selection of neural precursors based on their colony morphology (CoMo-NSC). The purity and NSC properties of established and extensively expanded CoMo-NSC were validated by expression of NSC markers (flow cytometry, mRNA sequencing), lack of pluripotent markers and by their tumorigenic/differentiation profile after in vivo spinal grafting in three different animal models, including (i) immunodeficient rats, (ii) immunosuppressed ALS rats (SOD1G93A), or (iii) spinally injured immunosuppressed minipigs. RESULTS: In vitro analysis of established CoMo-NSCs showed a consistent expression of NSC markers (Sox1, Sox2, Nestin, CD24) with lack of pluripotent markers (Nanog) and stable karyotype for more than 15 passages. Gene profiling and histology revealed that spinally grafted CoMo-NSCs differentiate into neurons, astrocytes, and oligodendrocytes over a 2-6-month period in vivo without forming neoplastic derivatives or abnormal structures. Moreover, transplanted CoMo-NSCs formed neurons with synaptic contacts and glia in a variety of host environments including immunodeficient rats, immunosuppressed ALS rats (SOD1G93A), or spinally injured minipigs, indicating these cells have favorable safety and differentiation characteristics. CONCLUSIONS: These data demonstrate that manually selected CoMo-NSCs represent a safe and expandable NSC population which can effectively be used in prospective human clinical cell replacement trials for the treatment of a variety of neurodegenerative disorders, including ALS, stroke, spinal traumatic, or spinal ischemic injury.

Adipogenic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells in Pig Transgenic Model Expressing Human Mutant Huntingtin.

BACKGROUND: Although the highest expression of mutant huntingtin (mtHtt) was observed in the brain, its negative effects were also apparent in other tissues. Specifically, mtHtt impairs metabolic homeostasis and causes transcriptional dysregulation in adipose tissue. Adipogenic differentiation can be induced by the activation of two transcription factors: CCAAT/enhancer-binding protein alpha (CEBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). These same transcription factors were found to be compromised in some tissues of Huntington's disease (HD) mouse models and in lymphocytes of HD patients. OBJECTIVE: This study investigated the adipogenic potential of mesenchymal stem cells (MSCs) derived from transgenic Huntington's disease (TgHD) minipigs expressing human mtHtt (1-548aa) containing 124 glutamines. Two differentiation conditions were used, employing PPARγ agonist rosiglitazone or indomethacin. METHODS: Bone marrow MSCs were isolated from TgHD and WT minipig siblings and compared by their cluster of differentiation using flow cytometry. Their adipogenic potential in vitro was analyzed using quantitative immunofluorescence and western blot analysis of transcription factors and adipogenic markers. RESULTS: Flow cytometry analysis did not reveal any significant difference between WT and TgHD MSCs. Nevertheless, following differentiation into adipocytes, the expression of CEBPα nuclear, PPARγ and adipogenic marker FABP4/AP2 were significantly lower in TgHD cells compared to WT cells. In addition, we proved both rosiglitazone and indomethacin to be efficient for adipogenic differentiation of porcine MSCs, with rosiglitazone showing a better adipogenic profile. CONCLUSIONS: We demonstrated a negative influence of mtHtt on adipogenic differentiation of porcine MSCs in vitro associated with compromised expression of adipogenic transcription factors.

AAV5-miHTT Gene Therapy Demonstrates Broad Distribution and Strong Human Mutant Huntingtin Lowering in a Huntington's Disease Minipig Model.

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Previously, we showed strong huntingtin reduction and prevention of neuronal dysfunction in HD rodents using an engineered microRNA targeting human huntingtin, delivered via adeno-associated virus (AAV) serotype 5 vector with a transgene encoding an engineered miRNA against HTT mRNA (AAV5-miHTT). One of the challenges of rodents as a model of neurodegenerative diseases is their relatively small brain, making successful translation to the HD patient difficult. This is particularly relevant for gene therapy approaches, where distribution achieved upon local administration into the parenchyma is likely dependent on brain size and structure. Here, we aimed to demonstrate the translation of huntingtin-lowering gene therapy to a large-animal brain. We investigated the feasibility, efficacy, and tolerability of one-time intracranial administration of AAV5-miHTT in the transgenic HD (tgHD) minipig model. We detected widespread dose-dependent distribution of AAV5-miHTT throughout the tgHD minipig brain that correlated with the engineered microRNA expression. Both human mutant huntingtin mRNA and protein were significantly reduced in all brain regions transduced by AAV5-miHTT. The combination of widespread vector distribution and extensive huntingtin lowering observed with AAV5-miHTT supports the translation of a huntingtin-lowering gene therapy for HD from preclinical studies into the clinic.

Prevention of esophageal strictures after circumferential endoscopic submucosal dissection.

Endoscopic submucosal dissection or widespread endoscopic resection allow the radical removal of circumferential or near-circumferential neoplastic esophageal lesions. The advantage of these endoscopic methods is mini-invasivity and low risk of major adverse events compared to traditional esophagectomy. The major drawback of these extensive resections is the development of stricture - the risk is 70-80% if more than 75% of the circumference is removed and almost 100% if the whole circumference is removed. Thus, an effective method to prevent post-ER/ESD esophageal stricture would be of major benefit, because treatment of strictures requires multiple sessions of endoscopic dilatation and may carry a risk of perforation. Moreover, not all strictures are easy to treat and some patients may develop refractory strictures. There are several techniques and methods, which have been tested in both experimental and/or clinical studies but no one has received general acceptance based on results of high-quality evidence. The studies are usually small with a limited number of patients, there is a lack of randomized controlled trials and some techniques have been described only in experimental studies. Thus, prevention of post-ESD strictures remains an unresolved issue. On the other hand, because of the high risk of stricture and partially proven effectiveness of some preventive techniques, a preventive strategy should be considered in patients undergoing extensive ER/ESD in the esophagus. There is, however, no evidence about the superiority or inferiority of a particular preventive strategy compared to other techniques, moreover, there is paucity of data assessing the effectiveness of the combination of different preventive methods. The best preventive strategies known so far include 1) oral or local administration of corticosteroids; and 2) preventive stenting. Other strategies (preventive sessions of endoscopic dilatation or tissue engineering methods) have unproven efficacy or are too demanding for practical use. Nevertheless, the use of (any) preventive strategy after extensive ER/ESD of the esophagus probably reduces the risk of stricture and the number of endoscopic dilatations, therefore, it should be considered in these patients. However, there is a need for high quality evidence as well as for new ideas and approaches to resolve this important clinical problem.

Survival of syngeneic and allogeneic iPSC-derived neural precursors after spinal grafting in minipigs.

The use of autologous (or syngeneic) cells derived from induced pluripotent stem cells (iPSCs) holds great promise for future clinical use in a wide range of diseases and injuries. It is expected that cell replacement therapies using autologous cells would forego the need for immunosuppression, otherwise required in allogeneic transplantations. However, recent studies have shown the unexpected immune rejection of undifferentiated autologous mouse iPSCs after transplantation. Whether similar immunogenic properties are maintained in iPSC-derived lineage-committed cells (such as neural precursors) is relatively unknown. We demonstrate that syngeneic porcine iPSC-derived neural precursor cell (NPC) transplantation to the spinal cord in the absence of immunosuppression is associated with long-term survival and neuronal and glial differentiation. No tumor formation was noted. Similar cell engraftment and differentiation were shown in spinally injured transiently immunosuppressed swine leukocyte antigen (SLA)-mismatched allogeneic pigs. These data demonstrate that iPSC-NPCs can be grafted into syngeneic recipients in the absence of immunosuppression and that temporary immunosuppression is sufficient to induce long-term immune tolerance after NPC engraftment into spinally injured allogeneic recipients. Collectively, our results show that iPSC-NPCs represent an alternative source of transplantable NPCs for the treatment of a variety of disorders affecting the spinal cord, including trauma, ischemia, or amyotrophic lateral sclerosis.

Subpial Adeno-associated Virus 9 (AAV9) Vector Delivery in Adult Mice.

The successful development of a subpial adeno-associated virus 9 (AAV9) vector delivery technique in adult rats and pigs has been reported on previously. Using subpially-placed polyethylene catheters (PE-10 or PE-5) for AAV9 delivery, potent transgene expression through the spinal parenchyma (white and gray matter) in subpially-injected spinal segments has been demonstrated. Because of the wide range of transgenic mouse models of neurodegenerative diseases, there is a strong desire for the development of a potent central nervous system (CNS)-targeted vector delivery technique in adult mice. Accordingly, the present study describes the development of a spinal subpial vector delivery device and technique to permit safe and effective spinal AAV9 delivery in adult C57BL/6J mice. In spinally immobilized and anesthetized mice, the pia mater (cervical 1 and lumbar 1-2 spinal segmental level) was incised with a sharp 34 G needle using an XYZ manipulator. A second XYZ manipulator was then used to advance a blunt 36G needle into the lumbar and/or cervical subpial space. The AAV9 vector (3-5 µL; 1.2 x 1013 genome copies (gc)) encoding green fluorescent protein (GFP) was then injected subpially. After injections, neurological function (motor and sensory) was assessed periodically, and animals were perfusion-fixed 14 days after AAV9 delivery with 4% paraformaldehyde. Analysis of horizontal or transverse spinal cord sections showed transgene expression throughout the entire spinal cord, in both gray and white matter. In addition, intense retrogradely-mediated GFP expression was seen in the descending motor axons and neurons in the motor cortex, nucleus ruber, and formatio reticularis. No neurological dysfunction was noted in any animals. These data show that the subpial vector delivery technique can successfully be used in adult mice, without causing procedure-related spinal cord injury, and is associated with highly potent transgene expression throughout the spinal neuraxis.

A new experimental model of calculous cholecystitis suitable for the evaluation and training of minimally invasive approaches to cholecystectomy.

BACKGROUND: Novel, less invasive approaches such as single-incision laparoscopic cholecystectomy or natural orifice transluminal endoscopic surgery require preclinical evaluation and training. Therefore, there is a need for an experimental model closely mimicking the clinical situation. The aim of our study was to create an experimental model of calculous cholecystitis in a large laboratory animal and test its feasibility for the evaluation of different techniques of cholecystectomy. METHODS: In 11 laboratory pigs, gallstones were placed inside the gallbladder laparoscopically. Levels of inflammatory markers-leucocytes (WBC), C-reactive protein (CRP) and interleukin 6 (IL-6)-were monitored on the postoperative days (POD) 1, 2, 3, 7 and 30. Abdominal ultrasound was performed 2 and 4 weeks after the operation. Four weeks after the lithiasis induction, laparoscopic cholecystectomy was performed. The control group consisted of ten healthy animals in which a cholecystectomy was performed. The pigs were monitored for 30 days after surgery. All removed gallbladders were assessed histologically. RESULTS: The induction of lithiasis took 42 (35-52) min with no morbidity and mortality. The values of WBC, CRP and IL-6 increased significantly (vs. baseline) on POD 1, 2 and 3 (p < 0.05) and then normalised. Ultrasonography confirmed the presence of chronic calculous cholecystitis in all cases after 4 weeks. Laparoscopic cholecystectomy was significantly longer in animals with lithiasis, 63 (42-91) versus 46 (31-62) min (p = 0.018). Perioperative gallbladder wall perforation was significantly more frequent in the model group (8/11 vs. 1/10; p = 0.04). In contrast to healthy animals, all gallbladders with stones showed histological signs of chronic inflammation. CONCLUSIONS: A new animal model of calculous cholecystitis was created. Laparoscopic cholecystectomy was more technically difficult compared to operating on a healthy gallbladder. This model may be a suitable tool for effective preclinical training and also for the evaluation of different techniques of cholecystectomy.

Potent spinal parenchymal AAV9-mediated gene delivery by subpial injection in adult rats and pigs.

Effective in vivo use of adeno-associated virus (AAV)-based vectors to achieve gene-specific silencing or upregulation in the central nervous system has been limited by the inability to provide more than limited deep parenchymal expression in adult animals using delivery routes with the most clinical relevance (intravenous or intrathecal). Here, we demonstrate that the spinal pia membrane represents the primary barrier limiting effective AAV9 penetration into the spinal parenchyma after intrathecal AAV9 delivery. We develop a novel subpial AAV9 delivery technique and AAV9-dextran formulation. We use these in adult rats and pigs to show (i) potent spinal parenchymal transgene expression in white and gray matter including neurons, glial and endothelial cells after single bolus subpial AAV9 delivery; (ii) delivery to almost all apparent descending motor axons throughout the length of the spinal cord after cervical or thoracic subpial AAV9 injection; (iii) potent retrograde transgene expression in brain motor centers (motor cortex and brain stem); and (iv) the relative safety of this approach by defining normal neurological function for up to 6 months after AAV9 delivery. Thus, subpial delivery of AAV9 enables gene-based therapies with a wide range of potential experimental and clinical utilizations in adult animals and human patients.