Banca de DEFESA: GABRIELA DE CARVALHO CID

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : GABRIELA DE CARVALHO CID
DATA : 04/02/2020
HORA: 09:00
LOCAL: Instituto de Veterinária
TÍTULO:

Clinical-pathological and immunohistochemical evaluations of heart injuries in cats (Felis catus) with chronic renal disease

PALAVRAS-CHAVES:

Cat, Immunohistochemistry, Troponin, Miocardium

PÁGINAS: 77
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
SUBÁREA: Patologia Animal
ESPECIALIDADE: Anatomia Patologia Animal
RESUMO:

Troponin I (cTnI) is a protein expressed solely by myocardial cells, and therefore a sensitive and specific marker of cardiac injury in humans, dogs, cats and horses. Cardiac troponin I is not expressed in human skeletal muscle during fetal development, after trauma of the skeletal muscle, or during regeneration of such muscle. Unlike CK-MB, cardiac troponin I is highly specific for myocardial tissue, is not detectable in the blood of healthy people, shows a proportionally larger increase above threshold values, in cases of myocardial infarction may remain elevated for 7 10 days after the acute episode. For feline species, normal reference values for serum cTnI range from 0.03 to 0.16 ng / ml. The heart and kidneys are known to maintain hemodynamic homeostasis through a close relationship that regulates cardiac output, volume and vascular tone. Based on this information, the aim of this study was to evaluate the occurrence of damage to feline cardiomyocytes from chronic kidney disease (CKD) by measuring serum cTnI and to detect lesions in cardiomyocytes that sometimes show no morphological signs of aggression, besides demonstrate that the areas affected may be larger than that evidenced by hematoxylin & eosin (HE) staining. Twenty CKD felines (12 females and 8 males) from stage II were used, according to the proposed IRIS staging, regardless of breed, sex or age. Prior to the use of these animals, prior authorization from the guardian was requested for clinical examination followed by blood collection. As inclusion criteria, patients should have azotemia (Ref .: ≥ 1.6mg / dL). Animals with primary heart disease or other conditions that could lead to increased serum cTnI, such as hypertrophic cardiomyopathy, hyperthyroidism, primary or metastatic cardiac neoplasia, were excluded. Serum cTnI levels were evaluated in 20 cats; Of these, 10 had elevated serum troponin values - above 0.16 ng / mL. Of the 10 animals that had elevated serum cTnI values (Ref.:0.03 - 0.16ng / mL), two were in stage II and eight were in IRIS stage IV. For histological and immunohistochemical examination, regions of the apex, interventricular septum, left ventricle, right ventricle, left papillary muscle, right papillary muscle, right atrium and left atrium of the heart were collected. Immunohistochemical examination revealed marked loss of troponin in large groups of cardiomyocytes in two animals, and in 9 animals there was subtle to slight variation in the pattern of antitroponin C antibody labeling with isolated myocytes showing marked loss of immunoreactivity. In some cases there were several small groups of myocytes that had markedly decreased immunoreactivity mainly in the apex and papillary muscle regions; these areas corresponded to cells with imperceptible or very slight changes in HE. The results of the immunohistochemical evaluation confirmed the presence of regressive changes, ie, the technique was able to detect very early lesions (myocardial regions without morphological signs of aggression), and demonstrated that the areas injured / injured were larger than that evidenced in HE. The use of troponins as an important immunohistochemical indicator of cardiac injury has already been demonstrated in canines, cattle and sheep, however there were no studies in felines and, in the present study, all cardiomyocytes. with histological characteristics of cell death, did not show anti-troponin labeling, which demonstrates high marker sensitivity for the species. From these data, it is observed that 80% of the animals that presented increase in serum cTnI levels were in stage IV, that is, the higher the stage of CKD, the greater the probability of presenting myocardial injury. Another finding observed in the 10 animals with high cTnI values was that of these 4 were male and 6 were female and of the two animals within stage II there was a male and a female. In stage IV, there were three males and five females, suggesting that there is no correlation between sex and the degree of myocardial injury in cats with CKD. This study demonstrates that the use of myocardial injury biomarkers may help veterinarians to improve clinical judgment in decisions about therapeutic management in patients with CKD.

MEMBROS DA BANCA:
Presidente - 2606155 - VIVIAN DE ASSUNCAO NOGUEIRA CARVALHO
Interna - 2572430 - CRISTIANE DIVAN BALDANI
Externa ao Programa - 3377607 - APARECIDA ALVES DO NASCIMENTO
Externa à Instituição - MARIA CRISTINA NOBRE E CASTRO - UFF
Externa à Instituição - VALIRIA CERQUEIRA DUARTE