Combination HSCT and intravenous AAV-mediated gene therapy in a canine model proves pivotal for translation of Krabbe disease therapy.

Hematopoietic stem cell transplantation (HSCT) is the only approved treatment for presymptomatic infantile globoid cell leukodystrophy (GLD [Krabbe disease]). However, correction of disease is not complete, and outcomes remain poor. Herein we evaluated HSCT, intravenous (IV) adeno-associated virus rh10 vector (AAVrh10) gene therapy, and combination HSCT + IV AAVrh10 in the canine model of GLD. While HSCT alone resulted in no increase in survival as compared with untreated GLD dogs (∼16 weeks of age), combination HSCT + IV AAVrh10 at a dose of 4E13 genome copies (gc)/kg resulted in delayed disease progression and increased survival beyond 1 year of age. A 5-fold increase in AAVrh10 dose to 2E14 gc/kg, in combination with HSCT, normalized neurological dysfunction up to 2 years of age. IV AAVrh10 alone resulted in an average survival to 41.2 weeks of age. In the peripheral nervous system, IV AAVrh10 alone or in addition to HSCT normalized nerve conduction velocity, improved ultrastructure, and normalized GALC enzyme activity and psychosine concentration. In the central nervous system, only combination therapy at the highest dose was able to restore galactosylceramidase activity and psychosine concentrations to within the normal range. These data have now guided clinical translation of systemic AAV gene therapy as an addition to HSCT (NCT04693598, NCT05739643).

Canine Model of Ischemia-Induced Ventricular Tachycardia.

INTRODUCTION: Despite advances in antiarrhythmia therapies, ventricular tachycardia (VT) is a leading cause of sudden cardiac death. Investigation into the characteristics and new treatments for this arrhythmia is required to improve outcomes and a reproducible model of VT would be useful in these endeavors. We therefore created a canine model of ischemia-induced VT. MATERIALS AND METHODS: A pacing lead was implanted in the right ventricle in canines (n = 13) and the left anterior descending artery was occluded in two locations for 2 h and subsequently released to create an ischemia-reperfusion injury. In the 10 dogs that survived the first 48 h following the initial study, a terminal study was conducted 4-7 d later and VT was induced using premature stimulation or burst pacing through the right ventricle lead. The arrhythmia was terminated using either antitachycardia pacing or a defibrillatory shock. Multiple inductions into sustained VT were attempted. RESULTS: Sustained VT was induced in eight of 10 dogs with an average cycle length of 335 ± 70 bpm. Multiple episodes of VT were induced. Episodes of VT exhibited different electrocardiogram morphologies and cycle lengths in individual animals. CONCLUSIONS: This canine model provides a consistent technique for inducing multiple episodes of sustained VT. It may be useful for investigating VT mechanisms and testing novel therapeutics and treatments for patients with VT.

Reconstruction of Segmental Bone Defect in Canine Tibia Model Utilizing Bi-Phasic Scaffold: Pilot Study.

The reunion and restoration of large segmental bone defects pose significant clinical challenges. Conventional strategies primarily involve the combination of bone scaffolds with seeded cells and/or growth factors to regulate osteogenesis and angiogenesis. However, these therapies face inherent issues related to immunogenicity, tumorigenesis, bioactivity, and off-the-shelf transplantation. The biogenic micro-environment created by implanted bone grafts plays a crucial role in initiating the bone regeneration cascade. To address this, a highly porous bi-phasic ceramic synthetic bone graft, composed of hydroxyapatite (HA) and alumina (Al), was developed. This graft was employed to repair critical segmental defects, involving the creation of a 2 cm segmental defect in a canine tibia. The assessment of bone regeneration within the synthetic bone graft post-healing was conducted using scintigraphy, micro-CT, histology, and dynamic histomorphometry. The technique yielded pore sizes in the range of 230-430 µm as primary pores, 40-70 µm as secondary inner microchannels, and 200-400 nm as tertiary submicron surface holes. These three components are designed to mimic trabecular bone networks and to provide body fluid adsorption, diffusion, a nutritional supply, communication around the cells, and cell anchorage. The overall porosity was measured at 82.61 ± 1.28%. Both micro-CT imaging and histological analysis provided substantial evidence of robust bone formation and the successful reunion of the critical defect. Furthermore, an histology revealed the presence of vascularization within the newly formed bone area, clearly demonstrating trabecular and cortical bone formation at the 8-week mark post-implantation.

Variable flip angle T1 mapping and multi-echo T2 and T2* mapping magnetic resonance imaging sequences allow quantitative assessment of canine lumbar disc degeneration.

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.

Increased tumor-infiltrating lymphocyte density is associated with favorable outcomes in a comparative study of canine histiocytic sarcoma.

Histiocytic sarcoma (HS) is a rare and aggressive tumor in humans with no universally agreed standard of care therapy. Spontaneous canine HS exhibits increased prevalence in specific breeds, shares key genetic and biologic similarities with the human disease, and occurs in an immunocompetent setting. Previous data allude to the immunogenicity of this disease in both species, highlighting the potential for their successful treatment with immunotherapy. Quantification of CD3 tumor-infiltrating lymphocytes (TIL) in five cases of human HS revealed variable intra-tumoral T cell infiltration. Due to the paucity of human cases and lack of current model systems in which to appraise associations between anti-tumor immunity and treatment-outcome in HS, we analyzed clinical data and quantified TIL in 18 dogs that were previously diagnosed with localized HS and treated with curative-intent tumor resection with or without adjuvant chemotherapy. As in humans, assessment of TIL in biopsy tissues taken at diagnosis reveal a spectrum of immunologically "cold" to "hot" tumors. Importantly, we show that increased CD3 and granzyme B TIL are positively associated with favorable outcomes in dogs following surgical resection. NanoString transcriptional analyses revealed increased T cell and antigen presentation transcripts associated with prolonged survival in canine pulmonary HS and a decreased tumor immunogenicity profile associated with shorter survivals in splenic HS. Based on these findings, we propose that spontaneous canine HS is an accessible and powerful novel model to study tumor immunology and will provide a unique platform to preclinically appraise the efficacy and tolerability of anti-cancer immunotherapies for HS.

Dystrophin deficiency impairs vascular structure and function in the canine model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a muscle-wasting disease caused by dystrophin deficiency. Vascular dysfunction has been suggested as an underlying pathogenic mechanism in DMD. However, this has not been thoroughly studied in a large animal model. Here we investigated structural and functional changes in the vascular smooth muscle and endothelium of the canine DMD model. The expression of dystrophin and endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), and the structure and function of the femoral artery from 15 normal and 16 affected adult dogs were evaluated. Full-length dystrophin was detected in the endothelium and smooth muscle in normal but not affected dog arteries. Normal arteries lacked nNOS but expressed eNOS in the endothelium. NOS activity and eNOS expression were reduced in the endothelium of dystrophic dogs. Dystrophin deficiency resulted in structural remodeling of the artery. In affected dogs, the maximum tension induced by vasoconstrictor phenylephrine and endothelin-1 was significantly reduced. In addition, acetylcholine-mediated vasorelaxation was significantly impaired, whereas exogenous nitric oxide-induced vasorelaxation was significantly enhanced. Our results suggest that dystrophin plays a crucial role in maintaining the structure and function of vascular endothelium and smooth muscle in large mammals. Vascular defects may contribute to DMD pathogenesis. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Regeneration of emphysematous lungs using gelatin sheets that release basic fibroblast growth factor.

PURPOSE: Basic fibroblast growth factor (bFGF) induces regeneration and neovascularization of the lungs. We conducted this study to demonstrate the regeneration of emphysematous lungs achieved by gelatin sheets that slowly release bFGF into the visceral pleura in a canine model. METHODS: Porcine pancreatic elastase was used to induce bilateral lower lobe pulmonary emphysema in dogs. Slow-release bFGF gelatin sheets were attached to the visceral pleura of the left lower lobe via thoracotomy. The subjects were divided into two groups: one treated with gelatin sheets containing slow-release bFGF (bFGF+ group, n = 5), and the other, treated with only gelatin sheets (bFGF- group, n = 5). The subjects were euthanized after 28 days and histologic lung assessment was performed. The results were evaluated in terms of the mean linear intercept (MLI) and microvessel count. RESULTS: The MLI was significantly shorter in the bFGF+ group than in the bFGF- group; (110.0 ± 24.38 vs. 208.9 ± 33.08 µm; P = 0.0006). The microvessel count was not significantly different between the bFGF+ and bFGF- groups (12.20 ± 3.007 vs. 5.35 ± 2.3425; P = 0.075); however, it was significantly higher in the bFGF-attached lungs than in the emphysema group (12.20 ± 3.007 vs. 4.57 ± 0.8896; P = 0.012). CONCLUSIONS: Attaching gelatin sheets with slow-release bFGF to the visceral pleura induced lung regeneration and vascularization in a canine pulmonary emphysema model.

Medium-chain triglycerides dietary supplement improves cognitive abilities in canine epilepsy.

OBJECTIVE: Cognitive impairments (CI) have recently been identified in canine epilepsy patients. A medium-chain triglyceride (MCT) enriched diet has been demonstrated to improve cognition in aged dogs and seizure control in canine epilepsy. This study evaluates the short-term effects of MCT-oil consumption on cognitive abilities in dogs with epilepsy, a naturally occurring animal model. METHODS: A 6-month multicenter, prospective, randomized, double-blinded, controlled cross-over diet trial was conducted comparing dietary supplementation (DS) of MCT oil to a control oil. Allocation to dietary oil supplements, consisting of 9% total caloric intake, was block-randomized and supplemented into each dogs' diet for 3 months followed by a respective switch of DS-oil for a further 3 months. Noninvasive cognitive tests and a validated psychometric tool were utilized to evaluate cognitive function and perturbations associated with dietary intervention. RESULTS: Twenty-nine dogs completed the trial, of which 18 completed noninvasive cognitive testing. Spatial-working memory (P = 0.008), problem-solving ability (P = 0.048), and owner-reported trainability (P = 0.041) were significantly improved during MCT-oil supplementation compared to control-DS. SIGNIFICANCE: MCT-oil DS improves cognition in dogs with epilepsy when compared to a control-DS. MCT supplementation may represent a promising option to address CI associated with epilepsy.

Histopathologic findings of vascular damage after mechanical thrombectomy using stent retriever in canine models.

Although mechanical thrombectomy is a powerful predictor of stroke outcome, it induces vessel wall injury in the acute phase. This study aimed to analyze the degree and the condition of recovery of wall injury after the acute phase via angiography and histopathological analysis of autopsied canine models. Digital subtraction angiography (DSA) and embolization with autologous thrombus were performed in six canines. The model of arterial occlusion was effective in all target vessels. Mechanical thrombectomy was performed in completely occluded vessels using stent retriever. Follow-up angiographic and histopathologic evaluations were performed 1 month later. Complete recanalization using stent retriever was achieved in four cases. Slight residual vessel narrowing after recanalization and moderate narrowing was observed in one case each. Histopathological analysis showed that inflammation, hemorrhage, and device-induced medial injury were not observed in any of the cases. Severe intimal proliferation (grade 4), marked diffuse thrombosis (grade 4), and weak vascular endothelial cell loss (grade 1) were observed in one case and weak endovascular proliferation was observed in one case. Although successful complete recanalization was achieved with a single mechanical thrombectomy attempt and no change was observed in the follow-up DSA, special attention should be paid to postoperative follow-up, as device-induced intimal proliferation, diffuse thrombosis, and endothelial cell loss may remain after 1 month.

Comparison of two different methods of establishment of canine urethroplasty model: an experimental trial.

BACKGROUND: Graft substitute urethroplasty is recommended for patients with long segment anterior urethral stricture. The therapeutic effects of the grafts need to be validated on the animal models. Therefore the aim of this study was to compared the operative time, blood loss, intra- and post- operative complications of two different methods of establishment of canine urethroplasty model. METHODS: Twelve Beagle dogs were randomly separated into control and experimental group using a random number table. Six animals in the control group received the conventional urethroplasty, while the other 6 in the experimental group received the modified procedures. Tube cystostomy and urethroplasty were performed in the control group. The cystostomy not the tube cystostomy were performed in the experimental group, and the testes were simultaneously removed with the scrotum. Per- and postoperative outcomes, complications were evaluated. RESULTS: The urethroplasty were successfully performed for all dogs and all of these procedures were done by the same surgeon. The median operative time in the control and experimental groups was 186.8 min and 188.7 min respectively. The blood loss in the control and experimental groups was 40.8 ml and 45.8 ml respectively. No intraoperative complications occurred. 3 animals in the control group developed acute urinary retention after the accidental removal of suprapubic bladder tube and the cystostomy was done again. There was no occurrence of urinary retention in the experimental group. 4 animals in the control group developed the perineal hematoma, in which one animal had the urine leakage and incision infection. Perineal hematoma occurred in only one animal in the experimental group. CONCLUSION: The occurrence of urinary retention and perineal hematoma decreased in the modified group, in which the cystostomy not the tube cystostomy were performed and the testes with the scrotum were simultaneously removed.

Pathological changes within two weeks following spinal cord injury in a canine model.

PURPOSES: This study aimed to investigate the histopathological changes that occur within 2 weeks following spinal cord injury (SCI) in dogs. METHODS: Eight adult female Beagle dogs were included in this study, and SCI was induced using an epidural balloon catheter. Two dogs were killed at each of the following four time points: immediately after the procedure and 1 day, 1 week, and 2 weeks after the procedure. Neurological status was evaluated with five categories. Histopathological changes were visually observed for stained sections of formalin-fixed spinal cord to evaluate hemorrhage, spongiosis, necrosis, and gliosis morphologically. RESULTS: Along the 2 weeks post-injury, severe hemorrhage was observed at the primary injury site, the average diameter of which expanded quickly from 8 to 10 mm in 1 day and then decreased to 5 mm in 1 week. This indicates that the bleeding cavity expanded at the initial injury site to produce ascending and descending hemorrhage. The hemorrhage at the injury site resolved in 2 weeks. In contrast, spongiosis, parenchymal necrosis, and gliosis were first inconspicuous or mild and then became severe in 1 week or 2 weeks. Hemorrhage, hematoma, and other similar changes occurred at the regions approximately 20-mm rostral and caudal to the primary injury site. These changes were observed in both gray matter and white matter. CONCLUSIONS: This study is the first to assess the sequential histopathological changes in the acute and intermediate phases following SCI in dogs. Our findings enhance the usefulness of the canine intervertebral disk disease model in the assessment of secondary spinal cord histopathology in human SCI.

Cerebrospinal fluid and serum glycosphingolipid biomarkers in canine globoid cell leukodystrophy (Krabbe Disease).

Globoid cell leukodystrophy (GLD, Krabbe disease, Krabbe's disease) is caused by genetic mutations in the gene encoding, galactosylceramidase (GALC). Deficiency of this enzyme results in central and peripheral nervous system pathology, and is characterized by loss of myelin and an infiltration of globoid cells. The canine model of GLD provides a translational model which faithfully recapitulates much of the human disease pathology. Targeted lipidomic analysis was conducted in serum and cerebrospinal fluid (CSF) over the lifetime of GLD affected and normal canines, and in brain tissue at humane endpoint to better understand disease progression and identify potential biomarkers of disease. Psychosine, a substrate of GALC and primary contributor to the pathology in GLD, was observed to be significantly elevated in the serum and CSF by 2 or 4 weeks of age, respectively, and steadily increased over the lifetime of affected animals. Importantly, psychosine concentration strongly correlated with disease severity. Galactosylceramide, glucosylceramide, and lactosylceramide were also found to be elevated in the CSF of affected animals and increased with age. Psychosine and galactosylceramide were found to be significantly increased in brain tissue at humane endpoint. This study identified several biomarkers which may be useful in the development of therapeutics for GLD.

Skin microbiota and allergic symptoms associate with exposure to environmental microbes.

A rural environment and farming lifestyle are known to provide protection against allergic diseases. This protective effect is expected to be mediated via exposure to environmental microbes that are needed to support a normal immune tolerance. However, the triangle of interactions between environmental microbes, host microbiota, and immune system remains poorly understood. Here, we have studied these interactions using a canine model (two breeds, n = 169), providing an intermediate approach between complex human studies and artificial mouse model studies. We show that the skin microbiota reflects both the living environment and the lifestyle of a dog. Remarkably, the prevalence of spontaneous allergies is also associated with residential environment and lifestyle, such that allergies are most common among urban dogs living in single-person families without other animal contacts, and least common among rural dogs having opposite lifestyle features. Thus, we show that living environment and lifestyle concurrently associate with skin microbiota and allergies, suggesting that these factors might be causally related. Moreover, microbes commonly found on human skin tend to dominate the urban canine skin microbiota, while environmental microbes are rich in the rural canine skin microbiota. This in turn suggests that skin microbiota is a feasible indicator of exposure to environmental microbes. As short-term exposure to environmental microbes via exercise is not associated with allergies, we conclude that prominent and sustained exposure to environmental microbiotas should be promoted by urban planning and lifestyle changes to support health of urban populations.

Electrophysiological parameters and anatomical evaluation of left bundle branch pacing in an in vivo canine model.

INTRODUCTION: Left bundle branch pacing (LBBP), a form of conduction system pacing in addition to His bundle pacing (HBP), can potentially maintain left ventricular electrical synchrony with better sensing and a low and stable capture threshold. METHODS: We performed both HBP and LBBP using a canine model (n = 3; male; weight 30-40 kg). The electrocardiogram (ECG), intracardiac electrogram characteristics, and pacing parameters were compared between HBP and LBBP. The hearts were isolated and stained by Lugol's iodine (5%) to assess the relative locations of the leads in relation to the conduction system. RESULTS: The average potential to ventricle interval was longer with HBP compared to LBBP (26.67 ± 3.06 ms vs 12.67 ± 1.15 ms; P = .002). There were also notable differences in the pacing parameters between HBP and LBBP: R-wave amplitude (2.67 ± 0.42 mV vs 11.33 ± 3.06 mV; P = .008), pacing impedance (423.3 ± 40.4 vs 660.0 ± 45.8; P = .003), and threshold (2.30 ± 0.66 V/0.4ms vs 0.67 ± 0.15 V/0.4 ms; P = .014). The paced morphology of ECG was similar to the intrinsic with HBP while a right bundle branch block pattern was noted with LBBP. The anatomical evaluation revealed the location of the leads and the average lead depth was significantly more with LBBP as compared to HBP (12.33 ± 1.53 mm vs1.83 ± 0.29 mm; P < .0001). Furthermore, with LBBP, the tip of the lead helix was noted to be around the LBB. CONCLUSION: This in vivo canine model study confirms the significant differences between HBP and LBBP. Furthermore, this model provides a precise anatomic evaluation of the location and the depth of the leads in relation to the conduction system.

Laparoscopic based renal denervation in a canine neurogenic hypertension model.

BACKGROUND: Previous renal denervation (RDN) studies showed controversial results in reducing blood pressure. The aim of this study was to provide evidence supporting the effectiveness of laparoscopic-based renal denervation (L-RDN) in treating hypertension. METHODS: Sixteen Beagle dogs were randomly divided into RDN group (n = 12) and sham group (n = 4). Neurogenic hypertension was generated in all dogs via carotid artery route. L-RDN was performed in the RDN group, with sham operation performed as a control. Blood pressure (BP) changes were recorded at 2, 4, 6, and 8 weeks after the procedure. Changes in serum creatinine (sCr), blood urea nitrogen (BUN) and level of norepinephrine (NE) were analyzed. Histological changes of kidney and renal arteries were also evaluated. RESULTS: BP and NE levels were significantly elevated after hypertension induction (p < 0.01). Systolic and diastolic BP of RDN group were decreased by 15.5 mmHg and 7.3 mmHg (p < 0.0001 and p = 0.0021, respectively) at the eighth week after L-RDN. Invasive systolic and diastolic BP of RDN group were significantly decreased by 14.5 mmHg and 15.3 mmHg (p < 0.0001). In contrast, there was no significant decrease in blood pressure in the sham group. In addition, RDN group but not the sham group showed a significant decrease in NE levels (p < 0.001), while no significant changes in sCr and BUN were observed in both groups. Pathological examinations showed no discernible damage, tear, or dissection to the renal arteries in RND group. CONCLUSIONS: L-RDN lowered BP and NE levels in hypertensive dogs without affecting renal artery morphology and kidney function.

Metoprolol prevents neuronal dendrite remodeling in a canine model of chronic obstructive sleep apnea.

Obstructive sleep apnea (OSA) is closely associated with central nervous system diseases and could lead to autonomic nerve dysfunction, which is often seen in neurodegenerative diseases. Previous studies have shown that metoprolol prevents several chronic OSA-induced cardiovascular diseases through inhibiting autonomic nerve hyperactivity. It remains unclear whether chronic OSA can lead to dendritic remodeling in the brain, and whether metoprolol affects the dendritic remodeling. In this study we investigated the effect of metoprolol on dendrite morphology in a canine model of chronic OSA, which was established in beagles through clamping and reopening the endotracheal tube for 4 h every other day for 12 weeks. OSA beagles were administered metoprolol (5 mg· kg-1· d-1). The dendritic number, length, crossings and spine density of neurons in hippocampi and prefrontal cortices were assessed by Golgi staining. And the protein levels of hypoxia-inducible factor-1α (HIF-1α) and brain-derived neurotrophic factor (BDNF) were measured by Western blotting. We showed that chronic OSA successfully induced significant brain hypoxia evidenced by increased HIF-1α levels in CA1 region and dentate gyrus of hippocampi, as well as in prefrontal cortex. Furthermore, OSA led to markedly decreased dendrite number, length and intersections, spine loss as well as reduced BDNF levels. Administration of metoprolol effectively prevented the dendritic remodeling and spine loss induced by chronic OSA. In addition, administration of metoprolol reversed the decreased BDNF, which might be associated with the metoprolol-induced neuronal protection. In conclusion, metoprolol protects against neuronal dendritic remodeling in hippocampi and prefrontal cortices induced by chronic OSA in canine.

Posterolateral lumbar spine fusion with unidirectional porous beta-tricalcium phosphate in a canine model.

We investigated the use of the autologous iliac bone and unidirectional porous beta-tricalcium phosphate (UDPTCP) in posterolateral lumbar spine fusion (PLF). Ten canine PLF models were prepared. Using only the autologous bone as the control group, 100%, 75%, 50%, and 25% groups were prepared according to the mixing ratios of UDPTCP. Radiological evaluation and histological analysis were performed 12 weeks after surgery. Bone fusion was evaluated according to anteroposterior plain X-rays and coronal reconstruction CT views using four grades: 0 = no osteogenesis, 1 = only slight discontinuous osteogenesis between transverse processes, 2 = discontinuous osteogenesis between transverse processes, and 3 = continuous osteogenesis between transverse processes. Bone fusion determined by X-ray was 2.8 ± 0.5 in the control group, 0 in the 100% UDPTCP group (p = 0.02), 1.8 ± 0.5 (p = 0.03) in the 75% UDPTCP group, 2.5 ± 0.6 (p = 0.54) in the 50% UDPTCP group, and 2.8 ± 0.5 (p = 1.0) in the 25% UDPTCP group. The bone fusion score was significantly lower in the 75% and 100% UDPTCP groups than in the control group. Bone fusion determined by CT was 2.8 ± 0.5 in the control group, 1.0 ± 0.8 (p = 0.01) in the 100% UDPTCP group, 2.0 ± 0.0 (p = 0.02) in the 75% UDPTCP group, 2.5 ± 0.6 (p = 0.54) in the 50% UDPTCP group, and 2.8 ± 0.5 (p = 1.0) in the 25% UDPTCP group. Similar to the bone fusion determination by X-ray, the bone fusion score was significantly lower in the 75% and 100% UDPTCP groups. These data suggest that, in a canine PLF model, the appropriate mixing ratio of UDPTCP is 50% or less.

A novel mutation in PDE6B in Spanish Water Dogs with early-onset progressive retinal atrophy.

OBJECTIVE: To identify the underlying mutation in a recently identified early-onset progressive retinal atrophy (PRA) in the Spanish Water Dog (SWD) breed. ANIMAL STUDIED: Eighteen SWDs were used in this study. Six SWDs diagnosed with PRA and 12 phenotypically normal SWDs. PROCEDURES: An exclusion analysis using an established microsatellite panel to screen PRA candidate genes was combined with whole genome sequencing of two affected SWD siblings and two phenotypically normal SWDs (a sibling and the dam). RESULTS: A 6-bp deletion was identified in exon 19 of PDE6B removing two highly conserved amino acids from the enzymatic domain of the PDE6B protein (c.2218-2223del; p.Phe740_Phe741del). This segregated with the disease status in the small study pedigree. CONCLUSIONS: Identification of this novel PDE6B mutation adds to the already described PDE6B mutations responsible for PRA in the Irish Setter, Sloughi, and American Staffordshire Terrier dog breeds. A DNA-based test was designed to allow breeders to genotype their animals and make informed breeding decisions in the effort to eradicate PRA from the SWD breed.

Development of a Synthetic Training Model for Canine Thoracocentesis.

Thoracocentesis, a procedure in which air or fluid is removed from the pleural space, is used to relieve respiratory distress, and as a diagnostic procedure in human and veterinary medicine. Veterinary students commonly learn and practice the procedure on canine cadavers which are in limited supply and are not amenable to long-term storage and use. Practicing thoracocentesis on a cadaveric model also provides limited feedback indicative of success and/or procedural complications. One commercial model for practicing canine thoracocentesis is available, but it costs over US$2000 and is excessively bulky. In order to improve the learning process for veterinary students, we have developed a reusable synthetic canine thorax model that accurately replicates the thoracocentesis procedure, provides immediate feedback to the students and reduces the need for canine cadavers. The low cost of our product provides an efficient alternative to cadavers for instruction in veterinary schools or hospitals.

Erythropoietin inhalation enhances adult canine alveolar-capillary formation following pneumonectomy.

Paracrine erythropoietin (EPO) signaling in the lung recruits endothelial progenitor cells, promotes cell maturation and angiogenesis, and is upregulated during canine postpneumonectomy (PNX) compensatory lung growth. To determine whether inhalational delivery of exogenous EPO augments endogenous post-PNX lung growth, adult canines underwent right PNX and received, via a permanent tracheal stoma, weekly nebulization of recombinant human EPO-containing nanoparticles or empty nanoparticles (control) for 16 wk. Lung function was assessed under anesthesia pre- and post-PNX. The remaining lobes were fixed for detailed morphometric analysis. Compared with control treatment, EPO delivery significantly increased serum EPO concentration without altering systemic hematocrit or hemoglobin concentration and abrogated post-PNX lipid oxidative stress damage. EPO delivery modestly increased post-PNX volume densities of the alveolar septum per unit of lung volume and type II epithelium and endothelium per unit of septal tissue volume in selected lobes. EPO delivery also augmented the post-PNX increase in alveolar double-capillary profiles, a marker of intussusceptive capillary formation, in all remaining lobes. EPO treatment did not significantly alter absolute resting lung volumes, lung and membrane diffusing capacities, alveolar-capillary blood volume, pulmonary blood flow, lung compliance, or extravascular alveolar tissue volumes or surface areas. Results established the feasibility of chronic inhalational delivery of growth-modifying biologics in a large animal model. Exogenous EPO selectively enhanced cytoprotection and alveolar angiogenesis in remaining lobes but not whole-lung extravascular tissue growth or resting function; the nonuniform response contributes to structure-function discrepancy, a major challenge for interventions aimed at amplifying the innate potential for compensatory lung growth.