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Stern JA, Rivas VN, Kaplan JL, Ueda Y, Oldach MS, Ontiveros ES, Kooiker KB, van Dijk SJ, Harris SP. Hypertrophic cardiomyopathy in purpose-bred cats with the A31P mutation in cardiac myosin binding protein-C. Sci Rep 2023; 13:10319. [PMID: 37365215 PMCID: PMC10293195 DOI: 10.1038/s41598-023-36932-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
We sought to establish a large animal model of inherited hypertrophic cardiomyopathy (HCM) with sufficient disease severity and early penetrance for identification of novel therapeutic strategies. HCM is the most common inherited cardiac disorder affecting 1 in 250-500 people, yet few therapies for its treatment or prevention are available. A research colony of purpose-bred cats carrying the A31P mutation in MYBPC3 was founded using sperm from a single heterozygous male cat. Cardiac function in four generations was assessed by periodic echocardiography and measurement of blood biomarkers. Results showed that HCM penetrance was age-dependent, and that penetrance occurred earlier and was more severe in successive generations, especially in homozygotes. Homozygosity was also associated with progression from preclinical to clinical disease. A31P homozygous cats represent a heritable model of HCM with early disease penetrance and a severe phenotype necessary for interventional studies aimed at altering disease progression. The occurrence of a more severe phenotype in later generations of cats, and the occasional occurrence of HCM in wildtype cats suggests the presence of at least one gene modifier or a second causal variant in this research colony that exacerbates the HCM phenotype when inherited in combination with the A31P mutation.
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Affiliation(s)
- Joshua A Stern
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1038 William Moore Dr, Raleigh, NC, 27606, USA
| | - Victor N Rivas
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1038 William Moore Dr, Raleigh, NC, 27606, USA
| | - Joanna L Kaplan
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Yu Ueda
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1038 William Moore Dr, Raleigh, NC, 27606, USA
| | - Maureen S Oldach
- VCA Sacramento Veterinary Referral Center, 9801 Old Winery Place, Sacramento, CA, 95827, USA
| | - Eric S Ontiveros
- Rady Children's Institute for Genomic Medicine, 7910 Frost Street, San Diego, CA, 92123, USA
| | - Kristina B Kooiker
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, 98109, USA
| | - Sabine J van Dijk
- Department of Neurobiology, Physiology, and Behavior, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Samantha P Harris
- Department of Neurobiology, Physiology, and Behavior, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA.
- Department of Physiology, College of Medicine-Tucson, University of Arizona, 313 Medical Research Building, 1656 E Mabel St., Tucson, AZ, 85724, USA.
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Dobromylskyj MJ, Little CJ. Necropsy findings in a cat with diabetes mellitus and heart failure. JFMS Open Rep 2021; 7:20551169211055383. [PMID: 34707882 PMCID: PMC8544778 DOI: 10.1177/20551169211055383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 12/05/2022] Open
Abstract
Case summary A 7-year-old male neutered domestic shorthair cat, previously diagnosed and treated for diabetes mellitus (DM), subsequently presented in heart failure (HF). Echocardiography revealed biatrial and biventricular dilation with poor myocardial function, and a left atrial-to-aortic ratio of 1.95:1. There was caudal vena cava dilation, hepatomegaly and ascites. The HF was treated with furosemide for 5 weeks, but thereafter the cat presented recumbent and moribund, and was euthanased. Post-mortem findings included dilation of all four cardiac chambers with an increased heart weight. Microscopic examination of the heart revealed mild, predominantly interstitial or perivascular fibrosis throughout most of the myocardium, with small-to-medium-sized foci of replacement fibrosis within the left ventricular free wall and interventricular septum. There was evidence of myocyte degeneration, but myofibre disarray was mild and there was minimal evidence of inflammation. Relevance and novel information Cardiac disease is common in cats and while HF is less common, it is a frequent cause of clinical signs and death. DM is a relatively common feline endocrinopathy. This case report describes DM and HF presenting as comorbidities, including detailed ante- and post-mortem findings. The case, and the epidemiology of these conditions, raise the question of whether a form of diabetic cardiomyopathy exists in cats, as it appears to do in humans.
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Abstract
Practical relevance: Hypertrophic cardiomyopathy (HCM) is the most common form of feline
cardiomyopathy observed clinically and may affect up to approximately 15% of
the domestic cat population, primarily as a subclinical disease.
Fortunately, severe HCM, leading to heart failure or arterial
thromboembolism (ATE), only occurs in a small proportion of these cats. Patient group: Domestic cats of any age from 3 months upward, of either sex and of any
breed, can be affected. A higher prevalence in male and domestic shorthair
cats has been reported. Diagnostics: Subclinical feline HCM may or may not produce a heart murmur or gallop sound.
Substantial left atrial enlargement can often be identified radiographically
in cats with severe HCM. Biomarkers should not be relied on solely to
diagnose the disease. While severe feline HCM can usually be diagnosed via
echocardiography alone, feline HCM with mild to moderate left ventricular
(LV) wall thickening is a diagnosis of exclusion, which means there is no
definitive test for HCM in these cats and so other disorders that can cause
mild to moderate LV wall thickening (eg, hyperthyroidism, systemic
hypertension, acromegaly, dehydration) need to be ruled out. Key findings: While a genetic cause of HCM has been identified in two breeds and is
suspected in another, for most cats the cause is unknown. Systolic anterior
motion of the mitral valve (SAM) is the most common cause of dynamic left
ventricular outflow tract obstruction (DLVOTO) and, in turn, the most common
cause of a heart murmur with feline HCM. While severe DLVOTO is probably
clinically significant and so should be treated, lesser degrees probably are
not. Furthermore, since SAM can likely be induced in most cats with HCM, the
distinction between HCM without obstruction and HCM with obstruction (HOCM)
is of limited importance in cats. Diastolic dysfunction, and its
consequences of abnormally increased atrial pressure leading to signs of
heart failure, and sluggish atrial blood flow leading to ATE, is the primary
abnormality that causes clinical signs and death in affected cats. Treatment
(eg, loop diuretics) is aimed at controlling heart failure. Preventive
treatment (eg, antithrombotic drugs) is aimed at reducing the risk of
complications (eg, ATE). Conclusions: Most cats with HCM show no overt clinical signs and live a normal or
near-normal life despite this disease. However, a substantial minority of
cats develop overt clinical signs referable to heart failure or ATE that
require treatment. For most cats with clinical signs caused by HCM, the
long-term prognosis is poor to grave despite therapy. Areas of uncertainty: Genetic mutations (variants) that cause HCM have been identified in a few
breeds, but, despite valiant efforts, the cause of HCM in the vast majority
of cats remains unknown. No treatment currently exists that reverses or even
slows the cardiomyopathic process in HCM, again despite valiant efforts. The
search goes on.
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Affiliation(s)
- Mark D Kittleson
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, and Veterinary Information Network, 777 West Covell Boulevard, Davis, CA 95616, USA
| | - Etienne Côté
- Department of Companion Animals, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
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Oldach MS, Ueda Y, Ontiveros ES, Fousse SL, Visser LC, Stern JA. Acute pharmacodynamic effects of pimobendan in client-owned cats with subclinical hypertrophic cardiomyopathy. BMC Vet Res 2021; 17:89. [PMID: 33622315 PMCID: PMC7903657 DOI: 10.1186/s12917-021-02799-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 02/16/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Prior studies have suggested that pimobendan is associated with several positive effects in cats, including improved survival in cats with congestive heart failure and improved left atrial function in research colony cats with hypertrophic cardiomyopathy (HCM) and normal cats. However, there is still a paucity of pharmacodynamic data refuting or supporting the use of pimobendan in a clinical cat population. This clinical trial aimed to evaluate the pharmacodynamic effects and tolerability of a single dose of pimobendan in cats with HCM. Echocardiograms and Doppler-derived systolic blood pressures were performed in 21 client-owned cats with subclinical HCM at baseline and 90-min after oral administration of 1.25 mg of pimobendan (Vetmedin). Seven additional cats were evaluated post-placebo administration to account for intra-day variability. RESULTS Heart rate, systolic blood pressure, and murmur grade were not significantly different between baseline and post-pimobendan evaluations. Left auricular blood flow velocity, left atrial size, and left ventricular fractional shortening were not significantly different between baseline and post-pimobendan evaluations. Mean (± standard deviation) tissue Doppler peak systolic velocity of the mitral annulus was significantly higher following pimobendan (7.4 cm/s ± 1.5 vs 8.5 ± 1.6; p = 0.02). Median (min, max) left-ventricular outflow tract maximum velocity was significantly higher following pimobendan [1.9 m/sec (1.5, 3.4) vs 2.6 m/sec (2.0, 4.0); p = 0.01]. Mean right-ventricular outflow tract maximum velocity was also significantly higher following pimobendan (1.5 m/s ± 0.51 vs 2.0 ± 0.53; p = 0.004). Mean left atrial fractional shortening was significantly higher following pimobendan (28% ± 6 vs 32% ± 7; p = 0.02). No adverse events were observed following pimobendan administration. Right ventricular outflow tract velocity was significantly higher following placebo in control cats (1.02 ± 0.21 versus 1.31 ± 0.31; p = 0.01). No other significant differences were detected. CONCLUSIONS In client-owned cats with HCM, pimobendan acutely increased left atrial function and mildly increased left ventricular systolic function. Left ventricular outflow tract velocity was increased after pimobendan. Pimobendan was well tolerated in the acute setting in cats with HCM. The findings of this prospective, acute-dosing study confirm previous findings in research animals and retrospective analyses and suggest that chronic dosing studies are safe and warranted.
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Affiliation(s)
- Maureen S Oldach
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Yu Ueda
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA
| | - Eric S Ontiveros
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Samantha L Fousse
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Lance C Visser
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Joshua A Stern
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA.
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Ward JL, Kussin EZ, Tropf MA, Tou SP, DeFrancesco TC, Keene BW. Retrospective evaluation of the safety and tolerability of pimobendan in cats with obstructive vs nonobstructive cardiomyopathy. J Vet Intern Med 2020; 34:2211-2222. [PMID: 33026124 PMCID: PMC7694854 DOI: 10.1111/jvim.15920] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Pimobendan is frequently used off-label for treatments of cats with congestive heart failure (CHF). Concern exists regarding the safety of pimobendan in cats with outflow tract obstruction (OTO). OBJECTIVES In cats treated with pimobendan, incidence of adverse effects will not differ between cats with OTO vs cats with nonobstructive cardiomyopathy. ANIMALS Two-hundred sixty cats with CHF (57 with OTO, 203 with nonobstructive disease). METHODS Retrospective medical record review. Groups were compared using 2-sample t-tests, Wilcoxon rank-sum tests, and Fisher exact tests. RESULTS Compared to cats with nonobstructive cardiomyopathy, cats with OTO were younger (8.9 [interquartile range (IQR) 6.6] vs 10.8 [6.3] years, P = .0036), more likely to have a heart murmur (51/57 [90%] vs 76/203 [37.8%] cats, P < .0001), more likely to manifest CHF as pulmonary edema (53/57 [83%] vs 144/203 [70.9%] cats, P = .0004), and less likely to have pleural effusion (19/57 [33%] vs 122/203 [60.1%] cats, P = .0005). Adverse effects suspected to be related to pimobendan administration occurred in 12/260 cats (4.6%), including 11/203 cats (5.4%) with nonobstructive cardiomyopathy and 1/57 cat (2%) with OTO (P = .7). Pimobendan was discontinued due to adverse effects in 4/260 cats (1.5%), 3 with nonobstructive disease and 1 with OTO (P = 1.0). Acute adverse hemodynamic effects after pimobendan administration were not detected in any cats. CONCLUSIONS AND CLINICAL IMPORTANCE Pimobendan is well tolerated in cats with cardiomyopathy and CHF, regardless of the presence of OTO.
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Affiliation(s)
- Jessica L Ward
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Efrem Z Kussin
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Melissa A Tropf
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Sandra P Tou
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Teresa C DeFrancesco
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Bruce W Keene
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
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