Evaluation of Serum NT-proBNP and Cardiac Troponin I Concentrations in Dogs with Heartworm Disease

국문 초록 (Abstract)

본 연구는 심장사상충에 감염된 개에서 심근 손상을 나타내는 생체표지자(biomarker)인 혈청 NT-proBNP와 cTnI농도를 측정하였고, 개 심장사상충에서 임상증상 중 하나인 폐성고혈압의 중증도를 측정하여, 임상증상 중증도에 따른 농도 수치의 변화 및 폐성고혈압과의 상관관계를 알아보았다. 건강한 개 5마리와 심장사상충 감염된 개 10마리가 본 연구에 제공되었으며 ELISA 키트 검사로 심장사상충 감염을 확인하였고, 병력청취, 임상증상, 혈액검사, 흉부방사선 및 심장초음파를 이용하여 증상이 경미한 경증군으로, 증상이 심각한 중증군으로 분류하였다.
NT-proBNP의 측정은 IDEXX reference laboratory에 의뢰하여 측정하였고, cTnI는 ELISA방법으로 측정하였다. 폐성고혈압(Pulmonary hypertension)은 심장초음파를 통해 삼첨판의 역류속도를 측정하였다.
NT-proBNP 농도를 측정하였을 때, 수치는 건강한 개체군에 비해 중증군에서 유의적인 상승을 보였다(p　<　0.05). cTnI 농도를 측정하였을 때,수치가 건강한 개체군에 비해 중증군에서 유의적인 상승을 보였다(p　<　0.05). 폐성 고혈압의 압력구배를 측정 하였을 때, 수치는 중증군에서 경증군에 비해 유의적인 상승을 보였다. 압력구배와 NT-proBNP사이에 양의 상관관계가 확인되었고(r　=　0.818, p　<　0.01), 압력구배와 cTnI사이에도 양의 상관관계가 확인되었다(r　=　0.894 p　<　0.01). 각 군 별로 두 혈청 값의 연관성을 조사했을 때 경증 군에서는 상관관계가 확인되지 않았으나(r　=　0.707, p　=　0.182), 중증 군에서는 상관관계가 확인되었다(r　=　0.9, p　<　0.05).
본 연구 결과, 개에서 심장사상충감염증이 있을 때 혈청 NT-proBNP와 혈청 cTnI 수치는 임상증상이 중증일수록 두 수치가 유의적으로 증가하였으며, 폐성고혈압의 압력구배는 임상증상이 중증인 경우 유의적으로 증가하였다. 또한 임상증상이 중증일 경우, 두 생체표지자 간의 상관관계가 확인되었다. 하지만, 임상증상이 경증일 경우 두 수치는 정상 수치와 유의적인 차이가 없었고, 두 수치 간의 연관성 또한 확인되지 않았다.

다국어 초록 (Multilingual Abstract)

Objectives : Biomarkers used in dogs with heartworm disease include N-terminal pro B-type natriuretic peptide (NT-proBNP), Cardiac troponin I (cTnI), C-reactive protein (CRP), and D-dimer. Among these, NT-proBNP and cTnI are associated with damage to the myocardium. It is known that the value increases according to the severity of clinical signs in heartworm disease. Pulmonary hypertension is one of the clinical signs of canine heartworm disease. The purpose of this study is to investigate the change in the concentration of each biomarker, severity of pulmonary hypertension and the correlation between biomarkers according to the severity of clinical signs
Materials and Methods : Five healthy dogs and 10 heartworm-infected dogs were recruited for the study. The heartworm-infected group was classified based on the history, clinical signs, and blood assay, thoracic radiography, and echocardiography after confirming the infection according to the results of the commercial ELISA kit (SNAP test, IDEXX Laboratories, Maine, USA). Serum samples were sent to the IDEXX reference laboratory for NT-proBNP measurements, and cTnI was measured with ELISA. Echocardiography was used to calculate the pulmonary hypertension.
Results : NT-proBNP was higher in the severely infected group than the control group (p　<　0.05); cTnI was also higher in the severely infected group than the control group (p　<　0.05). The pressure gradient of pulmonary hypertension was higher in the severe group than the mild group (p < 0.05). The severity of pulmonary hypertension was correlated with NT-proBNP (r　=　0.818, p　<　0.01), cTnI (r　=　0.894, p　<　0.01).
When the correlation of the two serum values for each group was examined, a correlation was not found in the mild group (r　=　0.707, p　=　0.182), but a correlation was found in the severe group (r　=　0.9, p　<　0.05).
Conclusions : NT-proBNP and cTnI were significantly increased and correlated with severe clinical signs. Pulmonary hypertension was significant higher in the severe group than in the mild group. However, with mild clinical signs, the two biomarkers did not differ when compared to the normal values, and there was no correlation between the two values. Further research is needed on mild clinical signs.

목차 (Table of Contents)

• ABSTRACT - 1
• INTRODUCTION 3
• MATERIALS AND METHODS 6
• Study Animals- 6
• Blood sample collection- 7
• NT-proBNP assays- 7
• Cardiac troponin I assays 7
• Echocardiography- 8
• Statistical analysis- 8
• RESULTS 9
• DISCUSSION 16
• REFERENCES 19
• ABSTRACT IN KOREAN 22