Increased erythrocytic osmotic fragility in anemic domestic shorthair and purebred cats

OBJECTIVES

Increased erythrocytic osmotic fragility and splenomegaly have been reported in anemic Abyssinian and Somali cats. Here we report on this condition in anemic domestic shorthair cats and two other breeds, and describe common features of the clinicopathological profiles, management and outcomes.

METHODS

Anemic cats, other than Abyssinians and Somalis, were included. The erythrocytic osmotic fragility test was performed, known causes of anemia were excluded, the illness was followed and medical records were reviewed.

RESULTS

Twelve neutered cats were first found to be anemic between 0.5 and 9.0 years of age. Pallor, lethargy, inappetence, pica, weight loss and splenomegaly were commonly observed. A moderate-to-severe macrocytic and hypochromic anemia with variable regeneration was noted. Infectious disease screening, direct Coombs' and pyruvate kinase DNA mutation test results were negative. Freshly drawn blood did not appear hemolysed but became progressively lysed during storage at 4°C. The sigmoid osmotic fragility curves were moderately to severely right shifted, indicating erythrocytic fragility at 20°C. Cross-correction studies indicated an intrinsic red cell effect rather than plasma effect. Most cats were treated with immunosuppressive doses of prednisolone and doxycycline, with variable responses. Five cats with recurrent or persistent anemia responded well to splenectomy. However, two had occasional recurrence of severe anemia: one was found to be Bartonella vinsonii-positive during one episode and responded to azithromycin and prednisolone, while the other cat had two episodes of severe anemia of unknown cause. Finally, six cats were euthanized within 1 month and 7 years after initial presentation. Histopathology of six spleens revealed mainly congestion and extramedullary hematopoiesis.

CONCLUSIONS AND RELEVANCE

Similarly to Abyssinian and Somali cats, domestic shorthair and cats of other breeds can also develop severe erythrocytic osmotic fragility with anemia and splenomegaly, which should be considered as a differential diagnosis in anemic cats.

Xenotransfusion of anemic cats with blood compatibility issues: pre- and posttransfusion laboratory diagnostic and crossmatching studies

BACKGROUND

Finding compatible feline blood donors can be challenging. Canine blood has been occasionally used when compatible feline blood was not available in emergency situations.

OBJECTIVES

The study goals were to describe the effects of xenotransfusion in 2 anemic cats receiving canine blood because of discordant blood types and acute transfusion reaction, respectively, and to report in vitro heterotyping and crossmatching results between canine and feline blood samples.

MATERIAL AND METHODS

Blood samples from patients and other cats and dogs were typed, crossmatched, and assessed for alloantibodies using gel, card, and immunochromatographic strip techniques.

RESULTS

Cat 1 was found to have type AB blood. Cat 2, which experienced an acute transfusion reaction, had type A blood. Neither had detectable alloantibodies against feline RBC. Both cats transiently improved after transfusion with canine blood; however, acute intravascular hemolysis occurred and the PCV rapidly declined. Blood typing post xenotransfusion with DEA 1 strips revealed a positive control band that was absent in feline blood, thus allowing for the identification of transfused canine RBC. Longitudinal assessment revealed that canine RBC could no longer be detected 4 days after xenotransfusion. Major crossmatching (feline plasma with canine RBC) resulted in both positive and negative reactions, depending on the cat. Minor crossmatching results showed mostly incompatibility.

CONCLUSION

While both cats survived xenotransfusion, the positive control band on the DEA 1 strip revealed that transfused canine RBC were short-lived and intravascular hemolysis occurred. Crossmatch results between cats and dogs showed varied incompatibilities and may not predict transfusion reactions.

Molecular prevalence of multiple genetic disorders in Border collies in Japan and recommendations for genetic counselling

Reproductive management is necessary to prevent deleterious genetic disorders in purebred dogs, but comprehensive studies aimed at prevention of multiple underlying genetic disorders in a single breed have not been performed. The aims of this study were to examine mutant allele frequencies associated with multiple genetic disorders, using Border collies as a representative breed, and to make recommendations for prevention of the disorders. Genotyping of known mutations associated with seven recessive genetic disorders was performed using PCR assays. More than half (56%) of the Border collies had no mutant alleles associated with any of the seven disorders, suggesting that these disorders can be removed from the population over several generations. Since frequencies of each mutant allele differed among disorders, reproductive management should be performed after the establishment of prevention schemes that are appropriate for each disorder, the type and specificity of genetic test available, and the effective population size in each breeding colony.

Real-time PCR genotyping assay for canine progressive rod-cone degeneration and mutant allele frequency in Toy Poodles, Chihuahuas and Miniature Dachshunds in Japan

Canine progressive rod-cone degeneration (PRCD) is a middle- to late-onset, autosomal recessive, inherited retinal disorder caused by a substitution (c.5G>A) in the canine PRCD gene that has been identified in 29 or more purebred dogs. In the present study, a TaqMan probe-based real-time PCR assay was developed and evaluated for rapid genotyping and large-scale screening of the mutation. Furthermore, a genotyping survey was carried out in a population of the three most popular breeds in Japan (Toy Poodles, Chihuahuas and Miniature Dachshunds) to determine the current mutant allele frequency. The assay separated all the genotypes of canine PRCD rapidly, indicating its suitability for large-scale surveys. The results of the survey showed that the mutant allele frequency in Toy Poodles was high enough (approximately 0.09) to allow the establishment of measures for the prevention and control of this disorder in breeding kennels. The mutant allele was detected in Chihuahuas for the first time, but the frequency was lower (approximately 0.02) than that in Toy Poodles. The mutant allele was not detected in Miniature Dachshunds. This assay will allow the selective breeding of dogs from the two most popular breeds (Toy Poodle and Chihuahua) in Japan and effective prevention or control of the disorder.

Dog erythrocyte antigen 1: mode of inheritance and initial characterization

BACKGROUND

The dog erythrocyte antigen (DEA) 1 blood group system remains poorly defined.

OBJECTIVES

The purpose of the study was to determine the DEA 1 mode of inheritance and to characterize the DEA 1 antigen and alloantibodies.

ANIMALS

Canine research colony families, clinic canine patients, and DEA 1.2+ blood bank dogs were studied.

METHODS

Canine blood was typed by flow cytometry and immunochromatographic strips using anti-DEA 1 monoclonal antibodies. Gel column experiments with polyclonal and immunoblotting with monoclonal anti-DEA 1 antibodies were performed to analyze select samples. Cross-reactivity of human typing reagents against canine RBC and one monoclonal anti-DEA 1 antibody against human RBC panels was assessed.

RESULTS

Typing of 12 families comprising 144 dogs indicated an autosomal dominant inheritance with ≥ 4 alleles: DEA 1- (0) and DEA 1+ weak (1+), intermediate (2+), and strong (3+ and 4+). Samples from 6 dogs previously typed as DEA 1.2+ were typed as DEA 1+ or DEA 1- using monoclonal antibodies. Human typing reagents produced varied reactions in tube agglutination experiments against DEA 1+ and DEA 1- RBC. Polypeptide bands were not detected on immunoblots using a monoclonal anti-DEA 1 antibody, therefore the anti-DEA 1 antibody may be specific for conformational epitopes lost during processing.

CONCLUSIONS

The autosomal dominant inheritance of DEA 1 with ≥ 4 alleles indicates a complex blood group system; the antigenicity of each DEA 1+ type will need to be determined. The biochemical nature of the DEA 1 antigen(s) appears different from human blood group systems tested.

Change in intrarenal Ghrelin expression in immune complex-mediated glomerular disease in dogs

Ghrelin is a peptide hormone that is mainly produced by the stomach. The kidney is a major source of local ghrelin, and maintaining body fluid balance is considered a critical role of renal ghrelin. However, there are no reports on renal ghrelin in small animal medicine. The present study investigated the intrarenal localization of and change in ghrelin expression in dogs with immune complex-mediated glomerulonephritis (ICGN). Ghrelin immunoreactivity (IR) was observed in the distal tubules of normal kidneys. Ghrelin IR was weak in ICGN kidneys, and the quantitative ghrelin IR score was significantly lower in ICGN kidneys than in normal kidneys. In cases of ICGN, plasma creatinine concentrations showed a positive correlation with the ghrelin IR score.

Expression of Autophagy-Related Proteins in the Spinal Cord of Pembroke Welsh Corgi Dogs With Canine Degenerative Myelopathy

Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease frequently found in Pembroke Welsh Corgi (PWC) dogs, and it has clinical and pathologic similarities to human amyotrophic lateral sclerosis. Autophagy is a major intracellular protein degradation system. Abnormalities of autophagy—resulting in cell death through mechanisms called type II programmed cell death—have recently been reported to occur in various neurodegenerative diseases, including amyotrophic lateral sclerosis. Thus, the distribution and expression levels of proteins involved in autophagy were examined in the spinal cords of 8 PWC dogs suffering from DM with superoxide dismutase mutation, 5 non-DM PWC dogs, and 6 Beagle dogs without neurologic signs. There was no significant difference in the ratio of neurons with microtubule-associated protein light chain 3 (LC3)–positive somata relative to those that were LC3 negative among the 3 groups, whereas the number of LC3-positive neurites was significantly increased in DM dogs. Punctate LC3 immunoreactivity did not colocalize with a lysosome marker, LAMP2 (lysosome-associated membrane protein 2). NBR1 (neighbor of BRCA gene 1) was localized mostly in reactive astrocytes, whereas there were p62 (p62/A170/SQSTM1)–positive foci in the neuropil of the spinal cord of DM dogs. Western blotting revealed in DM dogs the decreased expression of Beclin1 and Atg16 L, which are molecules involved in formation of the isolation membrane. These findings suggest that altered autophagosome degradation may result in LC3 and p62 accumulation in the DM spinal cord, whereas the early stage of membrane formation is likely to be downregulated.

Real-time PCR genotyping assay for feline erythrocyte pyruvate kinase deficiency and mutant allele frequency in purebred cats in Japan

Erythrocyte pyruvate kinase (PK) deficiency is an inherited glycolytic erythroenzymopathy caused by mutations of the PKLR gene. A causative mutation of the feline PKLR gene was originally identified in Abyssinian and Somali cats in the U.S.A. In the present study, a TaqMan probe-based real-time PCR genotyping assay was developed and evaluated for rapid genotyping and large-scale screening for this mutation. Furthermore, a genotyping survey was carried out in a population of four popular purebred cats in Japan to determine the current mutant allele frequency. The assay clearly displayed all genotypes of feline PK deficiency, indicating its suitability for large-scale survey as well as diagnosis. The survey demonstrated that the mutant allele frequency in Abyssinian and Somali cats was high enough to warrant measures to control and prevent the disease. The mutant allele frequency was relatively low in Bengal and American Shorthair cats; however, the testing should still be carried out to prevent the spread of the disease. In addition, PK deficiency should always be considered in the differential diagnosis of anemia in purebred cats in Japan as well as worldwide.

Feline cystinuria caused by a missense mutation in the SLC3A1 gene

Background

Cystinuria is an inherited metabolic disease that is relatively common in dogs, but rare in cats and is characterized by defective amino acid reabsorption, leading to cystine urolithiasis.

Objectives

The aim of this study was to report on a mutation in a cystinuric cat.

Animals

A male domestic shorthair (DSH) cat with cystine calculi, 11 control cats from Wyoming, and 54 DSH and purebred control cats from elsewhere in the United States.

Methods

Exons of the SLC3A1 gene were sequenced from genomic DNA of the cystinuric cat and a healthy cat. Genetic screening for the discovered polymorphisms was conducted on all cats.

Results

A DSH cat showed stranguria beginning at 2 months of age, and cystine calculi were removed at 4 months of age. The cat was euthanized at 6 months of age because of neurological signs possibly related to arginine deficiency. Twenty‐five SLC3A1 polymorphisms were observed in the sequenced cats when compared to the feline reference sequence. The cystinuric cat was homozygous for 5 exonic and 8 noncoding SLC3A1 polymorphisms, and 1 of them was a unique missense mutation (c.1342C>T). This mutation results in a deleterious amino acid substitution (p.Arg448Trp) of a highly conserved arginine residue in the rBAT protein encoded by the SLC3A1 gene. This mutation was found previously in cystinuric human patients, but was not seen in any other tested cats.

Conclusions and Clinical Importance

This study is the first report of an SLC3A1 mutation causing cystinuria in a cat, and could be used to characterize other cystinuric cats at the molecular level.

Real-time PCR genotyping assay for GM2 gangliosidosis variant 0 in toy poodles and the mutant allele frequency in Japan

GM2 gangliosidosis variant 0 (Sandhoff disease, SD) is a fatal, progressive neurodegenerative lysosomal storage disease caused by mutations of the HEXB gene. In canine SD, a pathogenic mutation (c.283delG) of the canine HEXB gene has been identified in toy poodles. In the present study, a TaqMan probe-based real-time PCR genotyping assay was developed and evaluated for rapid and large-scale genotyping and screening for this mutation. Furthermore, a genotyping survey was carried out in a population of toy poodles in Japan to determine the current mutant allele frequency. The real-time PCR assay clearly showed all genotypes of canine SD. The assay was suitable for large-scale survey as well as diagnosis, because of its high throughput and rapidity. The genotyping survey demonstrated a carrier frequency of 0.2%, suggesting that the current mutant allele frequency is low in Japan. However, there may be population stratification in different places, because of the founder effect by some carriers. Therefore, this new assay will be useful for the prevention and control of SD in toy poodles.

Molecular epidemiology of canine GM1 gangliosidosis in the Shiba Inu breed in Japan: relationship between regional prevalence and carrier frequency

BACKGROUND

Canine GM1 gangliosidosis is a fatal disease in the Shiba Inu breed, which is one of the most popular traditional breeds in Japan and is maintained as a standard breed in many countries. Therefore, it is important to control and reduce the prevalence of GM1 gangliosidosis for maintaining the quality of this breed and to ensure supply of healthy dogs to prospective breeders and owners. This molecular epidemiological survey was performed to formulate an effective strategy for the control and prevention of this disease.

RESULTS

The survey was carried out among 590 clinically unaffected Shiba Inu dogs from the 8 districts of Japan, and a genotyping test was used to determine nation-wide and regional carrier frequencies. The number and native district of affected dogs identified in 16 years from 1997 to June 2013 were also surveyed retrospectively. Of the 590 dogs examined, 6 dogs (1.02%, 6/590) were carriers: 3 dogs (2.27%, 3/132) from the Kinki district and the other 3 dogs from the Hokkaido, Kanto, and Shikoku districts. The retrospective survey revealed 23 affected dogs, among which, 19 dogs (82.6%) were born within the last 7 years. Of the 23 affected dogs, 12 dogs (52.2%) were from the Kinki district. Pedigree analysis demonstrated that all the affected dogs and carriers with the pedigree information have a close blood relationship.

CONCLUSIONS

Our results showed that the current carrier frequency for GM1 gangliosidosis is on the average 1.02% in Japan and rather high in the Kinki district, which may be related to the high prevalence observed over the past 16 years in this region. This observation suggests that carrier dogs are distributed all over Japan; however, kennels in the Kinki district may face an increased risk of GM1 gangliosidosis. Therefore, for effective control and prevention of this disease, it is necessary to examine as many breeding dogs as possible from all regions of Japan, especially from kennels located in areas with high prevalence and carrier frequency.

Identification of Bangladeshi domestic cats with GM1 gangliosidosis caused by the c.1448G>C mutation of the feline GLB1 gene: case study

GM1 gangliosidosis is a fatal, progressive neurodegenerative lysosomal storage disease caused by mutations in the β-galactosidase (GLB1) gene. In feline GM1 gangliosidosis, a pathogenic mutation (c.1448G>C) in the feline GLB1 gene was identified in Siamese cats in the United States and Japan and in Korat cats in Western countries. The present study found the homozygous c.1448G>C mutation in 2 apparent littermate native kittens in Bangladesh that were exhibiting neurological signs. This is the first identification of GM1 gangliosidosis in native domestic cats in Southeast Asia. This pathogenic mutation seems to have been present in the domestic cat population in the Siamese region and may have been transferred to pure breeds such as Siamese and Korat cats originating in this region.

Neuronal ceroid lipofuscinosis in Border Collie dogs in Japan: clinical and molecular epidemiological study (2000-2011)

Neuronal ceroid lipofuscinosis (NCL) is an inherited, neurodegenerative lysosomal disease that causes premature death. The present study describes the clinical and molecular epidemiologic findings of NCL in Border Collies in Japan for 12 years, between 2000 and 2011. The number of affected dogs was surveyed, and their clinical characteristics were analyzed. In 4 kennels with affected dogs, the dogs were genotyped. The genetic relationships of all affected dogs and carriers identified were analyzed. The survey revealed 27 affected dogs, but there was a decreasing trend at the end of the study period. The clinical characteristics of these affected dogs were updated in detail. The genotyping survey demonstrated a high mutant allele frequency in examined kennels (34.8%). The pedigree analysis demonstrated that all affected dogs and carriers in Japan are related to some presumptive carriers imported from Oceania and having a common ancestor. The current high prevalence in Japan might be due to an overuse of these carriers by breeders without any knowledge of the disease. For NCL control and prevention, it is necessary to examine all breeding dogs, especially in kennels with a high prevalence. Such endeavors will reduce NCL prevalence and may already be contributing to the recent decreasing trend in Japan.

Real-time PCR genotyping assay for canine trapped neutrophil syndrome and high frequency of the mutant allele in Border collies

Trapped neutrophil syndrome is an autosomal recessive inherited neutropenia in Border collies. The causative mutation is a 4base pair deletion in exon 19 of the canine VPS13B gene. In this study, a real-time PCR assay was developed and a genotyping survey was carried out in Border collies in Japan. The carrier frequency was 11.1%, suggesting that the mutant allele frequency is high enough to warrant measures to control and prevent the disease.

Novel rapid genotyping assays for neuronal ceroid lipofuscinosis in Border Collie dogs and high frequency of the mutant allele in Japan

Neuronal ceroid lipofuscinosis (NCL) constitutes a group of recessively inherited lysosomal storage diseases that primarily affect neuronal cells. Such diseases share certain clinical and pathologic features in human beings and animals. Neuronal ceroid lipofuscinosis in Border Collie dogs was first detected in Australia in the 1980s, and the pathogenic mutation was shown to be a nonsense mutation (c.619C>T) in exon 4 in canine CLN5 gene. In the present study, novel rapid genotyping assays including polymerase chain reaction (PCR)-restriction fragment length polymorphism, PCR primer-induced restriction analysis, mutagenically separated PCR, and real-time PCR with TaqMan minor groove binder probes, were developed. The utility of microchip electrophoresis was also evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies in Japan using these assays to determine the current allele frequency in Japan, providing information to control and prevent this disease in the next stage. All assays developed in the current study are available to discriminate these genotypes, and microchip electrophoresis showed a timesaving advantage over agarose gel electrophoresis. Of all assays, real-time PCR was the most suitable for large-scale examination because of its high throughput. The genotyping survey demonstrated that the carrier frequency was 8.1%. This finding suggested that the mutant allele frequency of NCL in Border Collies is high enough in Japan that measures to control and prevent the disease would be warranted. The genotyping assays developed in the present study could contribute to the prevention of NCL in Border Collies.

A frameshift mutation in the canine HEXB gene in toy poodles with GM2 gangliosidosis variant 0 (Sandhoff disease)

GM2 gangliosidosis variant 0 (Sandhoff disease, SD) is a fatal, progressive neurodegenerative lysosomal storage disease caused by mutations in the HEXB gene. Toy poodles recently were reported as the second breed of dog with SD. The present paper describes the molecular defect of this canine SD as the first identification of a pathogenic mutation in the canine HEXB gene. Genomic and complementary DNA sequences covering exonic regions of the canine HEXB gene, except exon 1, were analysed using DNA and RNA in an affected dog. A homozygous single base pair deletion of guanine in exon 3 was identified at nucleotide position 283 of the putative open reading frame (c.283delG). This mutation has the potential to cause a frameshift resulting in the alteration of valine at amino acid position 59 to a stop codon (p.V59fsX). Genotyping using the mutagenically separated PCR method demonstrated a correlation between phenotype and genotype in dogs with a pedigree related to the disease and that the mutation was rare in a randomly-selected population of toy poodles. These results strongly suggest that the deletion is pathogenic.

A comparative study of chronic kidney disease in dogs and cats: induction of cyclooxygenases

The present study investigated whether renal cyclooxygenase (COX) induction is associated with the severity of chronic kidney disease (CKD) in dogs and cats. The collected kidneys were examined histopathologically and immunohistochemically. The immunoreactivities of COX-1 and COX-2 were evaluated quantitatively, and the correlations to the plasma creatinine concentrations, glomerular size, glomerulosclerosis, interstitial fibrosis, and interstitial cell infiltration were evaluated statistically. Immunoreactivities for COX-1 were heterogeneously observed in the medullary distal tubules and collecting ducts; no correlations with the severity of renal damage were detected. Immunoreactivities for COX-2 were heterogeneously observed in the macula densa (MD) regions. In dogs, the percentage of COX-2-positive MD was significantly correlated with the glomerular size. In cats, glomeruli with COX-2-positive MD had significantly higher sclerosis scores than those with COX-2-negative MD. In conclusion, renal COX-2 is induced in canine and feline CKD, especially in relation to the glomerular changes.

Nephron segment identification in the normal canine kidney by using lectin histochemistry

Lectin-binding patterns in normal canine kidneys were histochemically investigated using eight lectins. WGA, ConA, and RCA-I showed positive signals in glomerular capillary walls, with signals for RCA-I being detected heterogeneously. In tubular segments, signals for WGA, s-WGA, ConA, and RCA-I were distributed widely from proximal tubules to collecting ducts, whereas those for SBA, PNA, DBA, and UEA-I were localized in thin limbs of the loop of Henle, thick ascending limbs, distal tubules, or collecting ducts. Apart from PNA and UEA-I, lectins showed heterogeneous bindings in collecting ducts with the heterogeneity. UEA-I-positive reactions were restricted to those parts of the distal tubules in close proximity to the glomeruli, and in these parts, signals in the macula densa were markedly stronger than in other regions. Based on the present findings, lectin probes, singly or in combination, could be utilized to identify the affected nephron segment in canine renal pathology.

Rapid genotyping assays for the 4–base pair deletion of canine MDR1/ABCB1 gene and low frequency of the mutant allele in Border Collie dogs

P-glycoprotein, encoded by the MDR1 or ABCB1 gene, is an integral component of the blood–brain barrier as an efflux pump for xenobiotics crucial in limiting drug uptake into the central nervous system. Dogs homozygous for a 4–base pair deletion of the canine MDR1 gene show altered expression or function of P-glycoprotein, resulting in neurotoxicosis after administration of the substrate drugs. In the present study, the usefulness of microchip electrophoresis for genotyping assays detecting this deletion mutation was evaluated. Mutagenically separated polymerase chain reaction (MS-PCR) and real-time PCR assays were newly developed and evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies dogs in Japan to determine the allele frequency in this breed. Microchip electrophoresis showed advantages in detection sensitivity and time saving over other modes of electrophoresis. The MS-PCR assay clearly discriminated all genotypes. Real-time PCR assay was most suitable for a large-scale survey due to its high throughput and rapidity. The genotyping survey demonstrated that the carrier and mutant allele frequencies were 0.49% and 0.25%, respectively, suggesting that the mutant allele frequency in Border Collies is markedly low compared to that in the susceptible dog breeds such as rough and smooth Collies.