Severe SARS-CoV-2 Infection in a Cat with Hypertrophic Cardiomyopathy.

Coronavirus disease 19 (COVID-19), has claimed millions of human lives worldwide since the emergence of the zoonotic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China in December 2019. Notably, most severe and fatal SARS-CoV-2 infections in humans have been associated with underlying clinical conditions, including diabetes, hypertension and heart diseases. Here, we describe a case of severe SARS-CoV-2 infection in a domestic cat (Felis catus) that presented with hypertrophic cardiomyopathy (HCM), a chronic heart condition that has been described as a comorbidity of COVID-19 in humans and that is prevalent in domestic cats. The lung and heart of the affected cat presented clear evidence of SARS-CoV-2 replication, with histological lesions similar to those observed in humans with COVID-19 with high infectious viral loads being recovered from these organs. The study highlights the potential impact of comorbidities on the outcome of SARS-CoV-2 infection in animals and provides important information that may contribute to the development of a feline model with the potential to recapitulate the clinical outcomes of severe COVID-19 in humans.

Detection of SARS-CoV-2 in a cat owned by a COVID-19-affected patient in Spain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, is considered a zoonotic pathogen mainly transmitted human to human. Few reports indicate that pets may be exposed to the virus. The present report describes a cat suffering from severe respiratory distress and thrombocytopenia living with a family with several members affected by COVID-19. Clinical signs of the cat prompted humanitarian euthanasia and a detailed postmortem investigation to assess whether a COVID-19-like disease was causing the condition. Necropsy results showed the animal suffered from feline hypertrophic cardiomyopathy and severe pulmonary edema and thrombosis. SARS-CoV-2 RNA was only detected in nasal swab, nasal turbinates, and mesenteric lymph node, but no evidence of histopathological lesions compatible with a viral infection were detected. The cat seroconverted against SARS-CoV-2, further evidencing a productive infection in this animal. We conclude that the animal had a subclinical SARS-CoV-2 infection concomitant to an unrelated cardiomyopathy that led to euthanasia.

Marked Up-Regulation of ACE2 in Hearts of Patients With Obstructive Hypertrophic Cardiomyopathy: Implications for SARS-CoV-2-Mediated COVID-19.

OBJECTIVE: To explore the transcriptomic differences between patients with hypertrophic cardiomyopathy (HCM) and controls. PATIENTS AND METHODS: RNA was extracted from cardiac tissue flash frozen at therapeutic surgical septal myectomy for 106 patients with HCM and 39 healthy donor hearts. Expression profiling of 37,846 genes was performed using the Illumina Human HT-12v3 Expression BeadChip. All patients with HCM were genotyped for pathogenic variants causing HCM. Technical validation was performed using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. This study was started on January 1, 1999, and final analysis was completed on April 20, 2020. RESULTS: Overall, 22% of the transcriptome (8443 of 37,846 genes) was expressed differentially between HCM and control tissues. Analysis by genotype revealed that gene expression changes were similar among genotypic subgroups of HCM, with only 4% (1502 of 37,846) to 6% (2336 of 37,846) of the transcriptome exhibiting differential expression between genotypic subgroups. The qRT-PCR confirmed differential expression in 92% (11 of 12 genes) of tested transcripts. Notably, in the context of coronavirus disease 2019 (COVID-19), the transcript for angiotensin I converting enzyme 2 (ACE2), a negative regulator of the angiotensin system, was the single most up-regulated gene in HCM (fold-change, 3.53; q-value =1.30×10-23), which was confirmed by qRT-PCR in triplicate (fold change, 3.78; P=5.22×10-4), and Western blot confirmed greater than 5-fold overexpression of ACE2 protein (fold change, 5.34; P=1.66×10-6). CONCLUSION: More than 20% of the transcriptome is expressed differentially between HCM and control tissues. Importantly, ACE2 was the most up-regulated gene in HCM, indicating perhaps the heart's compensatory effort to mount an antihypertrophic, antifibrotic response. However, given that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses ACE2 for viral entry, this 5-fold increase in ACE2 protein may confer increased risk for COVID-19 manifestations and outcomes in patients with increased ACE2 transcript expression and protein levels in the heart.

Myocarditis caused by Feline Immunodeficiency Virus in Five Cats with Hypertrophic Cardiomyopathy.

Viral infections have been implicated as the cause of cardiomyopathy in several mammalian species. This study describes hypertrophic cardiomyopathy (HCM) and myocarditis associated with feline immunodeficiency virus (FIV) infection in five cats aged between 1 and 4 years. Clinical manifestations included dyspnoea in four animals, one of which also exhibited restlessness. One animal showed only lethargy, anorexia and vomiting. Necropsy examination revealed marked cardiomegaly, marked left ventricular hypertrophy and pallor of the myocardium and epicardium in all animals. Microscopical and immunohistochemical examination showed multifocal infiltration of the myocardium with T lymphocytes and fewer macrophages, neutrophils and plasma cells. An intense immunoreaction for FIV antigen in the cytoplasm and nucleus of lymphocytes and the cytoplasm of some macrophages was observed via immunohistochemistry (IHC). IHC did not reveal the presence of antigen from feline calicivirus, coronavirus, feline leukaemia virus, feline parvovirus, Chlamydia spp. or Toxoplasma gondii. The results demonstrate the occurrence of FIV infection in inflammatory cells in the myocardium of five cats with myocarditis and HCM.

HLA-DRB1 typing by micro-bead array assay identifies the origin of early lymphoproliferative disorder in a heart transplant recipient.

We report the case of a 68-year-old woman who underwent heart transplantation for hypertrophic cardiomyopathy. Two months after the transplant she developed mild fever and dyspnea with a marked drop in left ventricle ejection fraction of 31%. Coronary angiography was negative for cardiac allograft vasculopathy. Endomyocardial biopsy revealed ischemic damage with no evidence of acute cellular rejection, antibody-mediated rejection or viral myocarditis. A neoplastic process was suspected even though full-body computerized tomography was negative for malignancy. The patient died 4 months after transplantation. The autopsy showed acute antero-septal myocardial infarction due to a nodular epicardial EBV-related posttransplant lymphoproliferative disorder (PTLD) infiltrating the left anterior descending coronary artery with occlusive neoplastic thrombosis. We highlight two major aspects of this case: (1) the unusual occurrence of early PTLD involving the cardiac allograft and causing a fatal outcome, (2) the application of an immunological technique for HLA-DRB1 typing to posttransplant paraffin-embedded autopsy material to identify the recipient origin of this early malignancy, thus excluding a possible donor-transmitted neoplasm.

Myocarditis in hypertrophic cardiomyopathy patients presenting acute clinical deterioration.

AIM: We sought to determine whether myocarditis can be a major cause of acute electrical instability or clinical deterioration in HCM patients. METHODS AND RESULTS: A total of 119 HCM patients (69 M/50F, mean age 41 +/- 8), 42 with acute clinical deterioration and 77 clinically stable, underwent cardiac catheterization with left ventricular endomyocardial biopsy and gene analysis of major sarcomeric proteins. Endomyocardial tissue was processed for histology, immunohistochemistry, and polymerase chain reaction for the most common cardiotropic viruses. Controls were surgical samples from 50 patients with mitral stenosis. All 119 patients showed histological findings suggestive of HCM. In addition, CD45RO+ lymphocytes (> or =14/mm(2)) with focal necrosis of the adjacent severely hypertrophied and often disorganized myocytes, consistent with an overlapping active myocarditis, were observed in 28 of 42 unstable and none of 77 stable HCM patients. A viral genome was detected in 14 of 28 patients with myocarditis and in none of HCM patients without and in none of controls. No correlation between sarcomeric protein gene mutations and HCM clinical profile was observed. CONCLUSION: Myocarditis, often viral, represents a common cause of acute clinical deterioration in HCM. Its recognition can potentially affect disease prognosis and treatment.

The haplotype block, NFKBIL1-ATP6V1G2-BAT1-MICB-MICA, within the class III-class I boundary region of the human major histocompatibility complex may control susceptibility to hepatitis C virus-associated dilated cardiomyopathy.

Cardiomyopathy is a heart muscle disease with impaired stretch response that can result in severe heart failure and sudden death. A small proportion of hepatitis C virus (HCV)-infected patients may be predisposed to develop dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). The molecular mechanisms involved in the predisposition remain unknown due in part to the lack of information on their genetic background. Because the human leukocyte antigen (HLA) region has a pivotal role in controlling the susceptibility to HCV-induced liver disease, we hypothesized that particular HLA alleles and/or non-HLA gene alleles within the human major histocompatibility complex (MHC) genomic region might control the predisposition to HCV-associated DCM (HCV-DCM) and/or HCV-associated HCM (HCV-HCM). Here, we present mapping results of the MHC-related susceptibility gene locus for HCV-associated cardiomyopathy by analyzing microsatellite and single nucleotide polymorphism markers. To delineate the susceptibility locus, we genotyped 44 polymorphic markers scattered across the entire MHC region in a total of 59 patients (21 HCV-DCM and 38 HCV-HCM) and 120 controls. We mapped HCV-DCM susceptibility to a non-HLA gene locus spanning from NFKBIL1 to MICA gene loci within the MHC class III-class I boundary region. Our results showed that HCV-DCM was more strongly associated with alleles of the non-HLA genes rather than the HLA genes themselves. In addition, no significant association was found between the MHC markers and HCV-HCM. This marked difference in the MHC-related disease susceptibility for HCV- associated cardiomyopathy strongly suggests that the development of HCV- DCM and HCV-HCM is under the control of different pathogenic mechanisms.

Prevalence of hepatitis C virus infection among patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is defined as inappropriate ventricular hypertrophy without a cardiac or systemic cause. On the other hand, hepatitis C virus (HCV) causes extrahepatic manifestations as well as chronic persistent infection in hepatocytes. We studied the association of HCV infection with HCM, comparing the prevalence of HCV antibodies between HCM patients and age- and gender-matched controls with other cardiovascular diseases at a single institution, for reasons of exclusion of bias. We then described the clinical features and genotype analysis of HCV RNA in HCM. The diagnosis of HCM was established by echocardiographic demonstration of a hypertrophied (> or =15 mm), nondilated left ventricle in the absence of another systemic or cardiovascular disease capable of producing the magnitude of hypertrophy observed. The study population consisted of 80 patients with HCM, in whom HCV antibody was examined (55 men and 25 women; mean age 56.6 +/- 12.4 years; ranging from 19 to 80 years), compared with a total of 80 age- and gender-matched controls without HCM. The prevalence of HCV infection in patients with HCM (18/80) was significantly higher than in control subjects (5/80) (Chi(2) = 7.312, P = 0.007). Of the 12 patients in whom the genotype of HCV was analyzed, 7 had type 1b and 5 had type 2a. The prevalence of HCV infection was higher in patients with HCM than in age- and gender-matched control subjects with other cardiovascular diseases. The result suggests that HCV may play an important role in these HCV-positive HCM patients.

Hepatitis C virus from the hearts of patients with myocarditis and cardiomyopathy.

The myocardium may be the target of several types of viral infections. The importance of hepatitis C virus (HCV) infection has been recently noted in patients with myocarditis and in patients with dilated or hypertrophic cardiomyopathy. The present study sought to detect HCV genomes in formalin-fixed paraffin sections of autopsied hearts from patients with myocarditis and patients with dilated or hypertrophic cardiomyopathy. Paraffin sections were deparaffinized, RNA was extracted, and the positive and negative strands of HCV RNA were detected by performing reverse transcription and nested polymerase chain reaction. The polymerase chain reaction products were cloned and sequenced. beta-actin gene was used as a control for the successful amplification of a housekeeping gene. Among 106 hearts examined, beta-actin gene was amplified in 61 hearts (57.5%). Among the latter, HCV RNA was detected in 13 hearts (21.3%), and negative strands in 4 hearts (6.6%). HCV RNA was found in 4 hearts (33.3%) with myocarditis, in 3 hearts (11.5%) with dilated cardiomyopathy, and in 6 hearts (26.0%) with hypertrophic cardiomyopathy. The sequences recovered from nine patients were highly homologous to the standard strain of HCV. HCV genomes were not found in either 35 hearts from patients with myocardial infarction or 20 hearts from patients with noncardiac diseases. These HCV RNA positive samples were obtained from 1 heart in 1979, 7 hearts between 1980 and 1989, and 5 hearts since 1990, indicating that HCV RNA can be amplified from paraffin-embedded hearts preserved for many years. This method of detecting HCV genomes in formalin-fixed paraffin cardiac specimens has enabled us to widen our research into HCV infection and has been helpful in identifying the presence of HCV infection in cardiac myopathic disorders.

Idiopathic dilated cardiomyopathy: lack of association with hepatitis C virus infection.

OBJECTIVE: To determine whether there is an association between hepatitis C virus (HCV) infection and dilated cardiomyopathy in a well defined area of north western Greece; such an association has been reported elsewhere. DESIGN: Evaluation of consecutive patients with chronic HCV infection for the presence of clinical or subclinical manifestations of dilated cardiomyopathy by history, physical examination, and non-invasive laboratory procedures (ECG, chest x ray, and echocardiography) before the initiation of interferon alpha treatment; investigation for HCV infection markers in patients with dilated cardiomyopathy by enzyme and immunoblot assays (antibodies to HCV) and the reverse transcriptase polymerase chain reaction (HCV RNA). SETTING: A tertiary referral centre for patients with chronic hepatitis and dilated cardiomyopathy. PATIENTS: 102 patients with well defined chronic HCV infection and 55 patients with well established dilated cardiomyopathy were evaluated. MAIN OUTCOME MEASURES: The need for HCV testing in patients with dilated cardiomyopathy, or follow up for heart disease in patients with chronic HCV infection. RESULTS: None of the patients with chronic HCV infection had clinical or subclinical evidence of dilated cardiomyopathy from history and laboratory findings. None of the patients with dilated cardiomyopathy was positive for antibodies to HCV or viraemic on HCV RNA testing. CONCLUSIONS: The study neither confirms the findings of other investigators, nor indicates a pathogenic link between HCV and dilated cardiomyopathy. For this reason, at least in Greece, testing for HCV in patients with dilated cardiomyopathy or follow up for heart disease in HCV patients appears unnecessary. Genetic or other factors could be the reason for this discrepancy if previously reported associations between HCV and dilated cardiomyopathy or hypertrophic cardiomyopathy were not coincidental.

Molecular and immune mechanisms in the pathogenesis of cardiomyopathy--role of viruses, cytokines, and nitric oxide.

Myocarditis is thought to be commonly caused by various viruses, and accumulating evidence links viral myocarditis with the eventual development of dilated cardiomyopathy. Recently, the importance of hepatitis C virus infection was noted in patients with dilated and hypertrophic cardiomyopathy. Cytokines are being increasingly recognized as an important factor in the pathogenesis and pathophysiology of myocarditis and cardiomyopathy. Elevated levels of circulating cytokines have been reported in patients with heart failure, and various cytokines have been shown to depress myocardial contractility in vitro and in vivo. A number of reports have shown that cytokines generated by activated immune cells cause an increase in nitric oxide (NO) via induction of NO synthase. Increased generation of NO may induce negative inotropism and myocardial damage. This review discusses the etiology and pathogenesis of myocarditis and cardiomyopathy from this point of view.