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A 7 yr old female French bulldog exhibited recurrent purulent vulvar discharge following an episode of pyometra treated by ovariohysterectomy. The diagnosis of ureteral duplication was established through a combination of ultrasonography, computed tomography scanning, and cystoscopy/vaginoscopy. Despite initial medical intervention, the dog's clinical condition did not improve. Consequently, surgical treatment was pursued to remove the duplicated ureter while preserving the integrity of the urinary tract. Resection of the duplicated ureter was performed from the kidney to the bladder, and the blind ends left in place in the kidney and in the bladder wall were omentalized. Histopathological analysis confirmed the presence of the duplicated ureter. Postoperatively, the dog made a full recovery with no complications or urinary tract dysfunction. Long-term follow-up (11 mo) revealed complete resolution of all clinical signs. Ureteral duplication should be included in the differential diagnosis of vulvar purulent discharge in dogs. Removal of the abnormal ureter resulted in complete resolution of the clinical signs. This case underscores the importance of individualized treatment plans for ureteral duplications in dogs and the potential for successful surgical treatment in selected cases.
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Enfermedades de los Perros , Uréter , Animales , Femenino , Perros , Enfermedades de los Perros/cirugía , Enfermedades de los Perros/diagnóstico , Enfermedades de los Perros/diagnóstico por imagen , Enfermedades de los Perros/congénito , Uréter/anomalías , Uréter/cirugía , Piómetra/veterinaria , Piómetra/cirugía , Resultado del TratamientoRESUMEN
Axolotls (Ambystoma mexicanum) are extensively studied for their relevance in human medical research. Despite being critically endangered in the wild, they have gained popularity as household pets. Although they have been kept in captivity for over a century, detailed descriptions of their coelomic organ anatomy remain limited. Also, this species exhibits significant variations compared to other amphibians. Ultrasound is a non-invasive and painless medical imaging technique, ideally suited for investigating internal organs or structures. This study focused on describing the ultrasound appearance of the axolotl coelomic cavity. It details the identification, localization and parenchymal description of major organs in 28 neotenic axolotls using ultrasound frequencies ranging from 7 to 15 MHz. The accuracy of the results was validated by comparing ultrasound findings with necropsy results from one male and one female axolotl. The heart, lung surface, liver and reproductive tracts were visualized. Measurements, along with confidence intervals, were calculated for the spleen, kidneys, testicles, gastric wall, gallbladder, and pylorus. Occasional detection of hyperechoic millimetric particles in the gallbladder or ascites was noted. However, visualization of the pancreas and bladder was not possible. This research outcomes involve the development of a comprehensive atlas comprising images obtained throughout the study. Additionally, the experiment established a reproducible and readily accessible protocol for conducting anatomy-morphological assessments in axolotl medicine. This protocol stands as a crucial preliminary stage before advancing to lesion identification.
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Ambystoma mexicanum , Ultrasonografía , Animales , Ambystoma mexicanum/anatomía & histología , Proyectos Piloto , Ultrasonografía/métodos , Masculino , FemeninoRESUMEN
Background: Intervertebral disc degeneration is frequent in dogs and can be associated with symptoms and functional impairments. The degree of disc degeneration can be assessed on T2-weighted MRI scans using the Pfirrmann classification scheme, which was developed for the human spine. However, it could also be used to quantify the effectiveness of disc regeneration therapies. We developed and tested a deep learning tool able to automatically score the degree of disc degeneration in dog spines, starting from an existing model designed to process images of human patients. Methods: MRI midsagittal scans of 5991 lumbar discs of dog patients were collected and manually evaluated with the Pfirrmann scheme and a modified scheme with transitional grades. A deep learning model was trained to classify the disc images based on the two schemes and tested by comparing its performance with the model processing human images. Results: The determination of the Pfirrmann grade showed sensitivities higher than 83% for all degeneration grades, except for grade 5, which is rare in dog spines, and high specificities. In comparison, the correspondent human model had slightly higher sensitivities, on average 90% versus 85% for the canine model. The modified scheme with the fractional grades did not show significant advantages with respect to the original Pfirrmann grades. Conclusions: The novel tool was able to accurately and reliably score the severity of disc degeneration in dogs, although with a performance inferior than that of the human model. The tool has potential in the clinical management of disc degeneration in canine patients as well as in longitudinal studies evaluating regenerative therapies in dogs used as animal models of human disorders.
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Low back pain stands as a pervasive global health concern, afflicting almost 80% of adults at some point in their lives with nearly 40% attributable to intervertebral disc degeneration (IVDD). As only symptomatic relief can be offered to patients there is a dire need for innovative treatments.Given the accumulating evidence that multiple microRNAs (miRs) are dysregulated during IVDD, they could have a huge potential against this debilitating condition. The way miRs can profoundly modulate signaling pathways and influence several cellular processes at once is particularly exciting to tackle this multifaceted disorder. However, miR delivery encounters extracellular and intracellular biological barriers. A promising technology to address this challenge is the vectorization of miRs within nanoparticles, providing both protection and enhancing their uptake within the scarce target cells of the degenerated IVD. This comprehensive review presents the diverse spectrum of miRs' connection with IVDD and demonstrates their therapeutic potential when vectorized in nanomedicines.
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Degeneración del Disco Intervertebral , MicroARNs , Adulto , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Degeneración del Disco Intervertebral/tratamiento farmacológico , Degeneración del Disco Intervertebral/metabolismo , Nanomedicina , Transducción de SeñalRESUMEN
Magnetic resonance imaging is the gold standard for diagnosing intervertebral disc (IVD) degeneration in dogs. However, published methods for quantifying severity or progression of IVD degeneration are currently limited. Mapping MRI sequences are used in humans for quantifying IVD degeneration but have rarely been applied in dogs. The objective of this prospective, method comparison study was to evaluate variable flip angle T1 mapping and multiecho T2 and T2* mapping as methods for quantifying canine lumbar IVD degeneration in twenty canine patients without clinical signs of spinal disease. Ventral and dorsal lumbar IVD widths were measured on radiographs, and lumbar IVDs were assigned a qualitative Pfirrmann grade based on standard T2-weighted sequences. T1, T2, and T2* relaxation times of the nucleus pulposus (NP) were measured on corresponding maps using manual-drawn ROIs. Strong intra- and interrater agreements were found (P < 0.01) for NP relaxation times. Radiographic IVD widths and T1, T2, and T2* mapping NP relaxation times were negatively correlated with Pfirrmann grading (P < 0.01). Significant differences in T1 NP relaxation times were found between Pfirrmann grade I and the other grades (P < 0.01). Significant differences in T2 and T2* NP relaxation times were found between grade I and the other grades and between grades II and III (P < 0.01). Findings indicated that T1, T2, and T2* MRI mapping sequences are feasible in dogs. Measured NP relaxation times were repeatable and decreased when Pfirrmann grades increased. These methods may be useful for quantifying the effects of regenerative treatment interventions in future longitudinal studies.
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Enfermedades de los Perros , Degeneración del Disco Intervertebral , Disco Intervertebral , Humanos , Perros , Animales , Degeneración del Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/veterinaria , Estudios Prospectivos , Imagen por Resonancia Magnética/veterinaria , Imagen por Resonancia Magnética/métodos , Región Lumbosacra , Interpretación de Imagen Asistida por Computador , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/patología , Disco Intervertebral/diagnóstico por imagen , Enfermedades de los Perros/diagnóstico por imagen , Enfermedades de los Perros/patologíaRESUMEN
A 1-year-old, intact female, mixed-breed dog (border collie and springer spaniel) was initially evaluated for lethargy, fever, and ataxia and subsequently evaluated 2.5 y later following the onset of seizures. Over a 3-year interval, the dog underwent 3 computed tomography (CT) and 1 magnetic resonance imaging (MRI) examinations. A voluminous hyperattenuating lesion with a mass effect, exhibiting weak postcontrast enhancement and associated with surrounding diffuse parenchymal hypoattenuation, was observed in the first CT examination (3 d after initial clinical signs). The second CT examination (11 d later) revealed a hypoattenuating lesion with ring postcontrast enhancement. A clear reduction of the size of the mass, which presented as hyperattenuating with a severely postcontrast-enhanced center, was noted in the third CT examination (2.5 y after initial clinical signs and 3 mo after onset of seizures). The MRI examination, performed 3 mo after the third CT examination, showed a small lesion, T2*-gradient echo hypointense, with no peripheral halo noted in T2-weighted fluid-attenuated inversion recovery and with serpentiform enhancement from within the lesion to the meningeal region. These sequential imaging findings were consistent with intracerebral hemorrhage. Key clinical message: To the authors' knowledge, this is the first case of hyperthermia associated with intracerebral hemorrhage in a dog, although this is a common finding in human medicine. An intracerebral hemorrhage should be included in the differential diagnosis of an intracerebral mass, and performing sequential imaging examinations can help clarify the diagnosis.
Résultats de la tomodensitométrie et de l'imagerie par résonance magnétique chez un chien suspecté d'hémorragie intracérébrale. Une chienne de race mixte femelle intacte âgée d'un an (border collie et épagneul springer) a été initialement évaluée pour de la léthargie, fièvre et ataxie, puis évaluée 2,5 ans plus tard après le début des crises. Sur un intervalle de 3 ans, le chien a subi trois examens de tomodensitométrie (TDM) et un examen d'imagerie par résonance magnétique (IRM). Une volumineuse lésion hyperatténuante avec effet de masse, présentant un faible rehaussement post-contraste et associée à une hypo-atténuation parenchymateuse diffuse environnante, a été observée au premier examen TDM (3 j après les premiers signes cliniques). Le deuxième examen TDM (11 jours plus tard) a révélé une lésion hypo-atténuante avec un rehaussement post-contraste en anneau. Une nette réduction de la taille de la masse, qui se présentait comme hyperatténuante avec un centre fortement rehaussé après contraste, était notée au troisième examen TDM (2,5 ans après les premiers signes cliniques et 3 mois après le début des crises). L'examen IRM, réalisé 3 mois après le troisième examen par TDM, a montré une petite lésion, écho hypo-intense de gradient T2*, sans halo périphérique noté dans la récupération d'inversion atténuée par fluide en pondération T2 et avec un rehaussement serpentiforme de l'intérieur de la lésion vers la région méningée. Ces résultats d'imagerie séquentielle étaient compatibles avec une hémorragie intracérébrale.Message clinique clé :À la connaissance des auteurs, il s'agit du premier cas d'hyperthermie associée à une hémorragie intracérébrale chez un chien, bien qu'il s'agisse d'une observation courante en médecine humaine. Une hémorragie intracérébrale doit être incluse dans le diagnostic différentiel d'une masse intracérébrale, et la réalisation d'examens d'imagerie séquentiels peut aider à clarifier le diagnostic.(Traduit par Dr Serge Messier).
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Hemorragia Cerebral , Enfermedades de los Perros , Humanos , Perros , Femenino , Animales , Hemorragia Cerebral/diagnóstico por imagen , Hemorragia Cerebral/veterinaria , Imagen por Resonancia Magnética/veterinaria , Convulsiones/diagnóstico por imagen , Convulsiones/veterinaria , Tomografía Computarizada por Rayos X/veterinaria , Enfermedades de los Perros/diagnóstico por imagen , Enfermedades de los Perros/patologíaRESUMEN
A 6-year-old mixed-breed male Papillon dog, castrated at the age of 7 months, presented for work-up of a difficulty walking associated with constipation and urinary incontinence. Ultrasonography and radiography were consistent with a tumor of the prostate and lymph node metastases. An irregular osteoproliferation of the ventral edges of L5-L6-L7 suggested tumor invasion. Periosteal proliferative lesions of the pelvis, the femur, the humerus, the tibia and the calcaneus were consistent with hypertrophic osteopathy. Necropsy and histological examination confirmed the diagnosis of prostatic adenocarcinoma with lymph node, pulmonary, liver and bone metastases, associated with hypertrophic osteopathy.
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OBJECTIVE: To assess the feasibility of ultrasonography of the tympanic bullae (TB) in live, nonsedated rabbits (Oryctolagus cuniculus). ANIMALS: 40 healthy rabbits undergoing TB ultrasonography without sedation between September 2021 and May 2022. PROCEDURES: For each rabbit, fur was clipped over an area (3 X 3 cm) at the level of the angular process of each mandible, then 3 ultrasonographic planes of each TB were imaged via ventral approach, with measurement of the time taken to complete the examination. Three items were assessed for each plane: TB depth, wall integrity, and contents (present or absent). Results were compared for rabbits grouped as standard-sized breed type versus dwarf-sized breed type. RESULTS: The examination could be carried out successfully in 36 of 40 (90%) of rabbits with clipping. The restraint and examination were relatively well tolerated by the animals, except for the transverse sections. Obtaining oblique and longitudinal sections, carried out on 33 of 40 (83%) rabbits in our study, allowed for evaluation of the TB. The examination was feasible with all rabbit sizes. The depth of the TB was found to be linked to the size of the rabbit and especially to the size of its jaw. Visualization of the distal bulla wall was observed in 2 of the 40 (5%) subjects, consistent with abnormal fluid contents or bulla osteitis. CLINICAL RELEVANCE: Ultrasonography of the TB was easy to learn and rapid to perform, with a mean examination time of < 10 minutes (mean of 8.71 minutes) without any sedation.
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Vesícula , Conejos , Animales , Vesícula/veterinaria , Ultrasonografía/veterinaria , Ultrasonografía/métodosRESUMEN
Approximately 40% of cases of lower back pain are caused by disc degeneration disease (DDD). It is well established that microRNA (miR) dysregulation is a key player in various diseases, and its impact on DDD has recently been highlighted. RNAi (miR in particular) is increasingly being considered as a novel therapeutic tool. However, free miR is degraded rapidly in vivo, and its protection is thus a prerequisite. Nanoparticular platforms, such as lipid nanocapsules (LNC), could be specifically adapted for miR delivery, allowing the transfer and release of miR in the cell cytoplasm. The objective of the current study was to formulate and characterize miR-loaded LNC to establish their in vitro potential (cell internalization, bioactivity) as well as to determine the safety and feasibility of in situ intervertebral disc (IVD) injection of miR LNC in a healthy sheep model. Using a miR library, miR-155 was clearly identified as being involved in the DDD process and was selected for further assessment. miR-155-loaded LNC (miR-155 LNC) were successfully formulated using a phase inversion process, with the addition of lipoplexes in the cooling step. Following purification, miR-155 LNC were fully characterized, and the optimized formulation had an average diameter of 75 nm, a polydispersity index below 0.1, and a positive zeta potential. By fluorescence spectroscopy, an encapsulation efficiency (EE) of 75.6% and a drug loading (DL) of 0.6% were obtained, corresponding to a sufficient amount of miR per mL of LNC to potentially have a biological effect. The sustained release of miR-155 from LNC was demonstrated compared with free miR-155: only 22% was released after 2 h and 58% after 24 h. miR-155 protection against endonuclease degradation by LNC was confirmed by gel electrophoresis, a sine qua non condition for it to be administered in vivo. Cell viability assays were performed on human adipose stromal cells (hASCs) and ovine Nucleus pulposus cells (oNP), and a cytotoxicity of <30% was obtained at the considered concentrations. Additionally, miR-155 LNC cell internalization was demonstrated by flow cytometry and confocal imaging. Moreover, downregulation of total ERK1/2 in hASCs and oNP cells, after miR-155 LNC treatment, was demonstrated by Western blot and quantitative reverse-transcription PCR (qRT-PCR), thus confirming maintenance of its bioactivity after formulation and internalization. Finally, the feasibility and safety of miR-155 LNC in situ injection (compared to control groups: blank LNC and sham condition) was demonstrated in healthy sheep by imaging (MRI and T2wsi measurement) and histology (Boos' scoring) analysis. T2wsi was measured, and no significant difference was observed three months after the injection between the different conditions. No histological impact was observed, with no significant difference in Boos' scoring between the different conditions. All these results suggest LNC may be a potent strategy for the encapsulation and delivery of miR (particularly miR-155) and can be considered as a first step towards IVD regenerative medicine.
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Degeneración del Disco Intervertebral , MicroARNs , Nanocápsulas , Animales , Regulación hacia Abajo , Humanos , Degeneración del Disco Intervertebral/tratamiento farmacológico , Degeneración del Disco Intervertebral/patología , Lípidos/química , Nanocápsulas/química , OvinosRESUMEN
OBJECTIVES: The duodenal papilla (DP) is an anatomical structure located in the duodenal wall, a few centimetres from the pylorus. In cats, the pancreatic and bile ducts merge as they enter the DP, and this explains why cats are more likely than dogs to have concomitant digestive, pancreatic and hepatic infections. Ultrasonography of the DP has been previously established in dogs but not in cats. The purpose of our prospective study was to describe the ultrasound features of the DP in 30 adult clinically healthy cats. METHODS: A full abdominal ultrasound was performed. Five measurements were recorded: the width and the height in a transverse section; the length and the height in a longitudinal section; and the thickness of the duodenal wall adoral to the DP in a longitudinal section. The subjective appearance (echogenicity and shape) of the DP was described. RESULTS: The dimensions of the DP were a mean ± SD width of 3.13 ± 0.68 mm and height of 2.47 ± 0.63 mm in the transverse section, and length of 3.98 ± 1.27 mm and height of 2.44 ± 0.57 mm in the longitudinal section. The DP was homogeneous, subjectively isoechoic to fat and had a round and oval shape in the transverse and longitudinal sections, respectively. There was no correlation between the DP measurements and the weight, age or sex of the cats. The animals that were fed a mixed diet had a longer DP than those fed dry food. CONCLUSIONS AND RELEVANCE: This study provides reference values for the dimensions of the DP, as well as information on its ultrasonographic appearance in clinically healthy adult cats. We did not find any correlation between the age of the cats and the size of the papilla, but the age range was small and another study in older cats should be undertaken to address this more thoroughly.
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Gatos , Perros , Animales , Estudios ProspectivosRESUMEN
An easy, reliable, and time-efficient standardized approach for assessing lumbar intervertebral disc (IVD) degeneration with relaxation times measurements in pre-clinical and clinical studies is lacking. This prospective study aims to determine the most appropriate method for lumbar IVD degeneration (IDD) assessment in sheep by comparing three quantitative MRI sequences (variable-flip-angle T1 mapping, and multi-echo T2 and T2* mapping), correlating them with Pfirrmann grading and histology. Strong intra- and interrater agreements were found for Nucleus pulposus (NP) regions-of-interest (ROI). T1, T2, and T2* mapping correlated with Pfirrmann grading and histological scoring (p < 0.05) except for the most ventral rectangular ROI on T2 maps. Correlations were excellent for all of the T1 ROIs and the T2* NP ROIs. Highly significant differences in T1 values were found between all Pfirrmann grades except between grades I/II and between grades III/IV. Significant differences were identified in the T2 and the T2* values between all grades except between grades I/III. T1, T2, and T2* relaxation times measurements of the NP are an accurate and time-efficient tool to assess lumbar IDD in sheep. Variable-flip-angle T1 mapping may be further considered as a valuable method to investigate IDD and to assess the efficacy of regenerative treatments in longitudinal studies.
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Degeneración del Disco Intervertebral , Animales , Técnicas Histológicas , Degeneración del Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/patología , Imagen por Resonancia Magnética/métodos , Estudios Prospectivos , Registros , OvinosRESUMEN
The vertebral heart scale (VHS) was proposed by Buchanan and Bucheler as an objective method for estimating heart size in dogs. However, several studies have reported significant variation between breeds. The purpose of this retrospective study was to evaluate the VHS and to suggest a useful upper limit for normal heart size in Brittany Spaniels. The VHS was measured using a right lateral view in twenty-eight normal dogs and fifteen dogs with myxomatous mitral valve disease. The mean ± SD (standard deviation) VHS was 10.6 ± 0.2 vertebrae (v) in the normal dogs, which differs significantly from the mean VHS of 9.7 ± 0.5 v in Buchanan's original study with dogs of various breeds. The VHS in the dogs with myxomatous mitral valve disease was 11.9 ± 1.1 v. With a threshold value of 11.1 vertebrae, the sensitivity, specificity, positive and negative predictive values for diagnosing a cardiomegaly are 90%, 72%, 53% and 96%, respectively.
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BACKGROUND: The rabbit lumbar spine is a commonly utilized model for studying intervertebral disc degeneration and for the pre-clinical evaluation of regenerative therapies. Histopathology is the foundation for which alterations to disc morphology and cellularity with degeneration, or following repair or treatment are assessed. Despite this, no standardized histology grading scale has yet been established for the spine field for any of the frequently utilized animal models. AIMS: The purpose of this study was to establish a new standardized scoring system to assess disc degeneration and regeneration in the rabbit model. MATERIALS AND METHODS: The scoring system was formulated following a review of the literature and a survey of spine researchers. Validation of the scoring system was carried out using images provided by 4 independent laboratories, which were graded by 12 independent graders of varying experience levels. Reliability testing was performed via the computation of intra-class correlation coefficients (ICC) for each category and the total score. The scoring system was then further refined based on the results of the ICC analysis and discussions amongst the authors. RESULTS: The final general scoring system involves scoring 7 features (nucleus pulposus shape, area, cellularity and matrix condensation, annulus fibrosus/nucleus pulposus border appearance, annulus fibrosus morphology, and endplate sclerosis/thickening) on a 0 (healthy) to 2 (severe degeneration) scale. ICCs demonstrated overall moderate to good agreement across graders. An addendum to the main scoring system is also included for use in studies evaluating regenerative therapeutics, which involves scoring cell cloning and morphology within the nucleus pulposus and inner annulus fibrosus. DISCUSSION: Overall, this new scoring system provides an avenue to improve standardization, allow a more accurate comparison between labs and more robust evaluation of pathophysiology and regenerative treatments across the field. CONCLUSION: This study developed a histopathology scoring system for degeneration and regeneration in the rabbit model based on reported practice in the literature, a survey of spine researchers, and validation testing.
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BACKGROUND: Rats are a widely accepted preclinical model for evaluating intervertebral disc (IVD) degeneration and regeneration. IVD morphology is commonly assessed using histology, which forms the foundation for quantifying the state of IVD degeneration. IVD degeneration severity is evaluated using different grading systems that focus on distinct degenerative features. A standard grading system would facilitate more accurate comparison across laboratories and more robust comparisons of different models and interventions. AIMS: This study aimed to develop a histology grading system to quantify IVD degeneration for different rat models. MATERIALS & METHODS: This study involved a literature review, a survey of experts in the field, and a validation study using 25 slides that were scored by 15 graders from different international institutes to determine inter- and intra-rater reliability. RESULTS: A new IVD degeneration grading system was established and it consists of eight significant degenerative features, including nucleus pulposus (NP) shape, NP area, NP cell number, NP cell morphology, annulus fibrosus (AF) lamellar organization, AF tears/fissures/disruptions, NP-AF border appearance, as well as endplate disruptions/microfractures and osteophyte/ossification. The validation study indicated this system was easily adopted, and able to discern different severities of degenerative changes from different rat IVD degeneration models with high reproducibility for both experienced and inexperienced graders. In addition, a widely-accepted protocol for histological preparation of rat IVD samples based on the survey findings include paraffin embedding, sagittal orientation, section thickness < 10 µm, and staining using H&E and/or SO/FG to facilitate comparison across laboratories. CONCLUSION: The proposed histological preparation protocol and grading system provide a platform for more precise comparisons and more robust evaluation of rat IVD degeneration models and interventions across laboratories.
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PURPOSE: In the context of regenerative medicine strategies, based in particular on the injection of regenerative cells, biological factors, or biomaterials into the nucleus pulposus (NP), two main routes are used: the transpedicular approach (TPA) and the transannular approach (TAA). The purpose of our study was to compare the long-term consequences of the TPA and the TAA on intervertebral disc (IVD) health through a longitudinal follow-up in an ovine model. METHODS: The TPA and the TAA were performed on 12 IVDs from 3 sheep. Six discs were left untreated and used as controls. The route and injection feasibility, as well as the IVD environment integrity, were assessed by MRI (T2-weighted signal intensity), micro-CT scan, and histological analyses (Boos' scoring). The sheep were assessed at 1, 3, and 7 months. RESULTS: Both the TPA and the TAA allowed access to the NP. They both induced NP degeneration, as evidenced by a decrease in the T2wsi and an increase in the Boos' scores. The TPA led to persistent end-plate defects and herniation of NP tissue (Schmorl's node-like) after 7 months as well as the presence of osseous fragments in the NP. CONCLUSIONS: The TPA induced more severe lesions in IVDs and vertebrae compared to the TAA. The lesions induced by the TPA are reason to consider whether or not this route is optimal for studying IVD regenerative medicine approaches.
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Degeneración del Disco Intervertebral , Disco Intervertebral , Núcleo Pulposo , Animales , Modelos Animales de Enfermedad , Disco Intervertebral/diagnóstico por imagen , Disco Intervertebral/cirugía , Degeneración del Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/cirugía , Imagen por Resonancia Magnética , Ovinos , Rayos XRESUMEN
The recent description of resident stem/progenitor cells in degenerated intervertebral discs (IVDs) supports the notion that their regenerative capacities could be harnessed to stimulate endogenous repair of the nucleus pulposus (NP). In this study, we developed a delivery system based on pullulan microbeads (PMBs) for sequential release of the chemokine CCL-5 to recruit these disc stem/progenitor cells to the NP tissue, followed by the release of the growth factors TGF-ß1 and GDF-5 to induce the synthesis of a collagen type II- and aggrecan-rich extracellular matrix (ECM). Bioactivity of released CCL5 on human adipose-derived stem cells (hASCs), selected to mimic disc stem/progenitors, was demonstrated using a Transwell® chemotaxis assay. The regenerative effects of loaded PMBs were investigated in ex vivo spontaneously degenerated ovine IVDs. Fluorescent hASCs were seeded on the top cartilaginous endplates (CEPs); the degenerated NPs were injected with PMBs loaded with CCL5, TGF-ß1, and GDF-5; and the IVDs were then cultured for 3, 7, and 28 days to allow for cell migration and disc regeneration. The PMBs exhibited sustained release of biological factors for 21 days. Ex vivo migration of seeded hASCs from the CEP toward the NP was demonstrated, with the cells migrating a significantly greater distance when loaded PMBs were injected (5.8 ± 1.3 mm vs. 3.5 ± 1.8 mm with no injection of PMBs). In ovine IVDs, the overall NP cellularity, the collagen type II and the aggrecan staining intensities, and the Tie2+ progenitor cell density in the NP were increased at day 28 compared to the control groups. Considered together, PMBs loaded with CCL5/TGF-ß1/GDF-5 constitute an innovative and promising strategy for controlled release of growth factors to promote cell recruitment and extracellular matrix remodelling.
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Degeneración del Disco Intervertebral , Disco Intervertebral , Animales , Factores Biológicos , Movimiento Celular , Preparaciones de Acción Retardada , Matriz Extracelular , Humanos , Ovinos , Células MadreRESUMEN
The identification of the most efficient method for whole central nervous system targeting that is translatable to humans and the safest route of adeno-associated virus (AAV) administration is a major concern for future applications in clinics. Additionally, as many AAV serotypes were identified for gene introduction into the brain and the spinal cord, another key to human gene-therapy success is to determine the most efficient serotype. In this study, we compared lumbar intrathecal administration through catheter implantation and intracerebroventricular administration in the cynomolgus macaque. We also evaluated and compared two AAV serotypes that are currently used in clinical trials: AAV9 and AAVrh10. We demonstrated that AAV9 lumbar intrathecal delivery using a catheter achieved consistent transgene expression in the motor neurons of the spinal cord and in the neurons/glial cells of several brain regions, whereas AAV9 intracerebroventricular delivery led to a consistent transgene expression in the brain. In contrast, AAVrh10 lumbar intrathecal delivery led to rare motor neuron targeting. Finally, we found that AAV9 efficiently targets respiratory and skeletal muscles after injection into the cerebrospinal fluid (CSF), which represents an outstanding new property that can be useful for the treatment of diseases affecting both the central nervous system and muscle.
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Articular cartilage (AC) may be affected by many injuries including traumatic lesions that predispose to osteoarthritis. Currently there is no efficient cure for cartilage lesions. In that respect, new strategies for regenerating AC are contemplated with interest. In this context, we aim to develop and characterize an injectable, self-hardening, mechanically reinforced hydrogel (Si-HPCH) composed of silanised hydroxypropymethyl cellulose (Si-HPMC) mixed with silanised chitosan. The in vitro cytocompatibility of Si-HPCH was tested using human adipose stromal cells (hASC). In vivo, we first mixed Si-HPCH with hASC to observe cell viability after implantation in nude mice subcutis. Si-HPCH associated or not with canine ASC (cASC), was then tested for the repair of osteochondral defects in canine femoral condyles. Our data demonstrated that Si-HPCH supports hASC viability in culture. Moreover, Si-HPCH allows the transplantation of hASC in the subcutis of nude mice while maintaining their viability and secretory activity. In the canine osteochondral defect model, while the empty defects were only partially filled with a fibrous tissue, defects filled with Si-HPCH with or without cASC, revealed a significant osteochondral regeneration. To conclude, Si-HPCH is an injectable, self-setting and cytocompatible hydrogel able to support the in vitro and in vivo viability and activity of hASC as well as the regeneration of osteochondral defects in dogs when implanted alone or with ASC.
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OBJECTIVES: Polydactyly has been described in two breeds of domestic cats (Maine Coon and Pixie Bob) and in some outbred domestic cats (eg, Hemingway cats). In most cases, feline polydactyly is a non-syndromic preaxial polydactyly. Three variants located in a regulatory sequence involved in limb development, named ZRS (zone of polarising activity regulatory sequence), have been identified to be responsible for feline polydactyly. These variants have been found in outbred domestic cats in the UK (UK1 and UK2 variants) and in Hemingway cats in the USA (Hw variant). The aim of this study was to characterise the genetic features of polydactyly in Maine Coon cats. METHODS: Genotyping assay was used to identify the variant(s) segregating in a cohort of 75 polydactyl and non-polydactyl Maine Coon cats from different breeding lines from Europe, Canada and the USA. The authors performed a segregation analysis to identify the inheritance pattern of polydactyly in this cohort and analysed the population structure. RESULTS: The Hw allele was identified in a subset of polydactyl cats. Sequencing of two regulatory sequences involved in limb development did not reveal any other variant in polydactyl cats lacking the Hw allele. Additionally, genotype-phenotype and segregation analyses revealed the peculiar inheritance pattern of polydactyly in Maine Coon cats. The population structure analysis demonstrated a genetic distinction between Hw and Hw-free polydactyl cats. CONCLUSIONS AND RELEVANCE: Polydactyly in Maine Coon cats is inherited as an autosomal dominant trait with incomplete penetrance and variable expressivity, and this trait is characterised by genetic heterogeneity in the Maine Coon breed. Maine Coon breeders should be aware of this situation and adapt their breeding practices accordingly.