Immunohistochemical evidence for expression of fast-twitch type sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1) in German shepherd dogs with dilated cardiomyopathy myocardium.
OBJECTIVE
Dilated cardiomyopathy (DCM) is one of the most common acquired canine heart diseases. It is particularly common in large and giant breed dogs. Although a great deal is known about the clinical progression and manifestations of the disease, the underlying cellular and molecular mechanisms remain poorly understood. One widely held belief is that calcium-handling abnormalities are critically involved in the disease process. This study investigates the changes in expression of the sarco(endo)plasmic reticulum calcium ATPase (SERCA) isoforms in DCM myocardium from German shepherd dogs.


METHODS
Affected tissue samples were obtained from German shepherd dogs with DCM, euthanized for intractable congestive heart failure while normal myocardial tissue samples were obtained from German shepherd dogs, euthanized for non-cardiovascular reasons. Tissue microarrays containing normal and DCM myocardium samples were prepared, immunostained with SERCA1 and SERCA2 antibodies and analyzed.


RESULTS
We were able to demonstrate, for the first time, that while there is little change in the expression of the cardiac isoform (SERCA2), there is clear expression of the fast-twitch skeletal muscle isoform SERCA1 in the myocardium of dogs diagnosed with DCM.


CONCLUSIONS
We propose that SERCA1 expression is evidence of a natural adaptive response to the impaired Ca2+ handling thought to occur in German shepherd dogs with DCM and heart failure.
Summerfield
Nuala
N
North Downs Specialist Referrals, Bletchingley, Surrey RH1 4QP, United Kingdom.
Peters
Mary E
ME
Hercock
Carol A
CA
Mobasheri
Ali
A
Young
Iain S
IS
D000818:Animals; D002311:Cardiomyopathy, Dilated / Q000378:metabolism / Q000662:veterinary*; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D040081:Protein Array Analysis / Q000662:veterinary; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000096:biosynthesis* / Q000276:immunology
D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases