Multiparametric Comparison of Two TTA-Based Surgical Techniques in Dogs with Cranial Cruciate Ligament Tears

[EN] Tearing of the cranial cruciate ligament causes hindlimb lameness in dogs. Different surgical procedures have been proposed to treat this condition. In this study, two different TTA-based techniques and implants were compared. A total of 30 dogs were separated into two groups according to the technique and implant used (Porous TTA® or Model Xgen®). The aim of the study was to assess whether one of these techniques has better functional recovery of the joint, better bone consolidation after the osteotomy procedure and fewer osteoarthritic changes. We compared both groups up to 3 months after surgery. No significant differences were found in any of the assessed parameters. Thus, both procedures were found to be equally effective and safe.SIThanks to the dog owners for their cooperation.This research received no external funding

Effects of testosterone and exercise training on bone microstructure of rats

[EN] Background and Aim: Male hypogonadism results from failure to produce physiological levels of testosterone. Testosterone in men is essential in masculine development, sperm production, and adult man’s health. Osteoporosis is one of the consequences of hypogonadism. Regular physical exercise and exogenous testosterone administration are frequently used to prevent or treat this condition. This study aimed to understand the effects of lifelong exercise training and testosterone levels (isolated and together) in the main bone structure parameters. Materials and Methods: A total of 24 rats were used and randomly divided into four groups: Control group (CG; n=6), exercised group (EG, n=6), testosterone group (TG, n=6), and testosterone EG (TEG, n=6). A micro-computed tomography equipment was used to evaluate 15 bone parameters. Results: Both factors (exercise training and testosterone) seem to improve the bone resistance and microstructure, although in different bone characteristics. Testosterone influenced trabecular structure parameters, namely, connectivity density, trabecular number, and trabecular space. The exercise promoted alterations in bone structure as well, although, in most cases, in different bone structure parameters as bone mineral density and medullar mineral density. Conclusion: Overall, exercise and testosterone therapy seems to have a synergistic contribution to the general bone structure and resistance. Further studies are warranted, comparing different individual factors, as gender, lifestyle, or testosterone protocols, to constantly improve the medical management of hypogonadism (and osteoporosis)SIWe thank to Eva Pascual de la Calle y Vanessa Loredo López, from Unidad de Imagen PreclínicaBioterio, Universidad de Oviedo. This study was supported by National Funds by FCT – Portuguese Foundation for Science and Technology, under the projects UIDB/04033/2020, UIDB/CVT/00772/2020 and the Ph.D. grant 2021.04520.B

Development and Evaluation of a Disease Large Animal Model for Preclinical Assessment of Renal Denervation Therapies

[EN] New-generation catheters-based renal denervation (RDN) is under investigation for the treatment of uncontrolled hypertension (HTN). We assessed the feasibility of a large animal model of HTN to accommodate the human RDN devices. Ten minipigs were instrumented to measure blood pressure (BP) in an awake-state. HTN was induced with subcutaneous 11-deoxycorticosterone (DOCA, 100 mg/kg) implants. Five months after, the surviving animals underwent RDN with the Symplicity® system. Norepinephrine (NE) renal gradients were determined before and 1 month after RDN. Renal arteries were processed for histological (hematoxylin-eosin, Movat pentachrome) and immunohistochemical (S100, tyrosine-hydroxylase) analyses. BP significantly rose after DOCA implants. Six animals died prematurely, mainly from infectious causes. The surviving animals showed stable BP levels after 5 months. One month after RDN, nerve damage was showed in three animals, with impedance drop >10%, NE gradient drop and reduction in BP. The fourth animal showed no nerve damage, impedance drop <10%, NE gradient increase and no change in BP. In conclusion, the minipig model of DOCA-induced HTN is feasible, showing durable effects. High mortality should be addressed in next iterations of this model. RDN may partially offset the DOCA-induced HTN. Impedance drop and NE renal gradient could be markers of RDN success.SIThis research was funded by Consejería de Salud, Junta de Castilla and Leon, Spain, the Grant GRS 1001/A/2014.We want to thank Medtronic Iberia for the donation of the Symplicity catheters used in this experiment

Estudio de los efectos de las lesiones del labrum acetabular en la cadera en un modelo experimental lagomorfo adulto

Objetivo: El cartílago labral es una estructura cartilaginosa que recubre el acetábulo de la cadera. Su lesión es controvertida en cuanto a sus implicaciones debido a que no se conoce bien si es una causa de degeneración articular o sólo un cambio degenerativo más. Hemos diseñado un modelo animal en conejo para estudiar esta lesión. Material y metodología: Se utilizaron tres grupos de 13 animales a los que se lesionó una cadera dejando la otra como control y se les mantuvo estabulados al primer grupo 12 semanas, al segundo 18 y al tercero 30. Posteriormente se les realizó un estudio radiológico, otro por resonancia magnética y, tras su sacrificio, un estudio histológico. Resultados: No encontramos relación en nuestro modelo entre la lesión labral y los cambios degenerativos posteriores en los plazos citados. Tampoco encontramos daños labrales sin cicatrizar en el momento del sacrificio. Conclusión: En el modelo animal lagomorfo, la lesión labral no produce cambios degenerativos artrósicos y el cartílago labral podría presentar cierta capacidad de regeneración

Modelo experimental de insuficiencia mitral en modelo animal porcino

Introduction and objectives: There is great interest in the development of devices for the percutaneous management of mitral regurgitation (MR). For this reason, having an experimental model that reproduces the conditions of the disease is of great importance. Our objective was to validate an experimental model of MR in a porcine model. Methods: For the model creation phase 3, 2-month-old 25 ± 3 kg large white pigs were used. An acute myocardial infarction was caused in the circumflex artery territory that hampered the perfusion of the posteromedial papillary muscle. Then, volume overload was induced in the animal by creating an arteriovenous shunt and connecting the aorta and the pulmonary artery using a Dacron tube. Echocardiography and magnetic resonance imaging were performed before the intervention and on week 8. Afterwards, the animal was euthanized to conduct the pathological study. Results: One out of the 3 pigs died during the intervention due to ventricular fibrillation. The remaining 2 pigs survived the procedure and were euthanized as scheduled on week 8. In both cases a transmural infarction occurred, 1 at lateral level and the other one at posteroinferior level with moderate secondary mitral regurgitation. Ventricular dimensions and volumes increased and the overall contractility was maintained despite segmental alterations. Conclusions: The experimental model of chronic MR based on the ischemic damage of the posteromedial papillary muscle associated with volume overload is feasible, safe and reproducible. Also, it can be very useful to test the safety and efficacy of future devices for the management of this condition.Introducción y objetivos: Existe un creciente interés en el desarrollo de dispositivos para el tratamiento de la insuficiencia mitral (IM) de forma mínimamente invasiva. Para este propósito, disponer de un modelo experimental que reproduzca las condiciones de la enfermedad sería de gran utilidad. Nuestro objetivo fue validar un modelo experimental de IM en cerdos. Métodos: Para esta fase de creación del modelo se han utilizado 3 cerdos de raza large white, de 2 meses de edad y un peso de 25 ± 3 kg. Se provocó un infarto en el territorio de la arteria circunfleja que afectó la perfusión del músculo papilar posteromedial, y posteriormente se sometió al animal a una sobrecarga de volumen mediante creación de un shunt arteriovenoso, con la conexión de la aorta y la pulmonar mediante un tubo de dacrón. Se realizó análisis mediante ecocardiografía y resonancia magnética antes de la intervención y a las 8 semanas, y posteriormente el animal fue eutanasiado para realizar el estudio anatomopatológico. Resultados: De los 3 cerdos, 1 falleció durante la intervención por fibrilación ventricular y los otros 2 sobrevivieron al procedimiento y fueron eutanasiados como estaba previsto a las 8 semanas. En ambos se produjo un infarto transmural, uno lateral y otro posteroinferior, con IM moderada secundaria. Las dimensiones y los volúmenes ventriculares aumentaron, y la contractilidad global se mantuvo a pesar de las alteraciones segmentarias. Conclusiones: El modelo experimental de IM crónica basado en el daño isquémico del músculo papilar posteromedial asociado a una sobrecarga de volumen es factible, seguro y reproducible, y puede ser de gran utilidad para comprobar la seguridad y la eficacia de los futuros dispositivos para el tratamiento de esta afección