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Showing posts with label natriuretic peptide. Show all posts
Showing posts with label natriuretic peptide. Show all posts

Thursday, December 27, 2012

Evaluating natriuretic peptides in hyperthyroid cats

Menaut P, Connolly DJ, Volk A, et al. Circulating natriuretic peptide concentrations in hyperthyroid cats. J Small Anim Pract. 2012; 53: 673-8.

Natriuretic peptides (NPs) are neurohormones stored in heart muscle cells (atrial cardiomyocytes) and released in response to atrial stretch. They possess potent natriuretic and vasorelaxant properties. They have been shown to be chronically up-regulated in cats with underlying heart disease and have thus been used as a biomarker to detect occult heart disease and differentiate cardiac from non-cardiac dyspnea in emergency situations. In particular, the non-biologically active N-terminal fragment from atrial natriuretic peptide, (NT-proANP), and from brain natriuretic peptide, NT-proBNP, have commonly been studied due to their stability in plasma. 

Hyperthyroidism is the most common endocrine disease of cats. In humans with hyperthyroidism, a number of studies have shown NP concentrations to be elevated. Therefore, since NP measurement is increasingly being used to assess feline cardiac disease, determining the influence of elevated thyroid function on NP concentrations is essential.

In this study, 61 hyperthyroid cats were assessed before and after treatment for hyperthyroidism. Treatment included using methimazole or methimazole and subsequent surgical thyroidectomy. Cats with overt heart failure or systemic hypertension were excluded from the study due to previous reports showing these conditions to be associated with an increase in NT-proBNP. Assessment included full physical examination, systolic blood pressure (SBP), plasma biochemistries, total thyroid level (TT4), packed cell volume (PCV), and urinalysis, as well as measurement of NT-proBNP and NT-proANP concentrations. The length of time between pre- and post-treatment evaluation was 35 days and the length of time that the cats were on treatment before post-treatment sample was 28 days. Total T4, heart rate, SBP, and PCV all decreased and body weight and creatinine concentrations increased once euthyroidism was established. In addition, NT-proBNP significantly declined, but no change in NT-proANP concentrations was noted. In conclusion, hyperthyroidism has a modest but significant effect on elevating NT-proBNP with little effect on NT-proANP. Therefore, thyroid status should be taken into account when interpreting NT-proBNP results. [GO]

See also: Singletary GE, Rush JE, Fox PR, Stepien RL and Oyama MA. Effect of NT-pro-BNP assay on accuracy and confidence of general practitioners in diagnosing heart failure or respiratory disease in cats with respiratory signs. J Vet Intern Med. 2012; 26: 542-6.

Related blog articles:
Biochemical testing for feline heart disease (March 2009)
Cardiac biomarkers in feline heart disease (July 2011)

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+
Menaut P, Connolly DJ, Volk A, et al. Circulating natriuretic peptide concentrations in hyperthyroid cats. J Small Anim Pract. 2012; 53: 673-8.

Natriuretic peptides (NPs) are neurohormones stored in heart muscle cells (atrial cardiomyocytes) and released in response to atrial stretch. They possess potent natriuretic and vasorelaxant properties. They have been shown to be chronically up-regulated in cats with underlying heart disease and have thus been used as a biomarker to detect occult heart disease and differentiate cardiac from non-cardiac dyspnea in emergency situations. In particular, the non-biologically active N-terminal fragment from atrial natriuretic peptide, (NT-proANP), and from brain natriuretic peptide, NT-proBNP, have commonly been studied due to their stability in plasma. 

Hyperthyroidism is the most common endocrine disease of cats. In humans with hyperthyroidism, a number of studies have shown NP concentrations to be elevated. Therefore, since NP measurement is increasingly being used to assess feline cardiac disease, determining the influence of elevated thyroid function on NP concentrations is essential.

In this study, 61 hyperthyroid cats were assessed before and after treatment for hyperthyroidism. Treatment included using methimazole or methimazole and subsequent surgical thyroidectomy. Cats with overt heart failure or systemic hypertension were excluded from the study due to previous reports showing these conditions to be associated with an increase in NT-proBNP. Assessment included full physical examination, systolic blood pressure (SBP), plasma biochemistries, total thyroid level (TT4), packed cell volume (PCV), and urinalysis, as well as measurement of NT-proBNP and NT-proANP concentrations. The length of time between pre- and post-treatment evaluation was 35 days and the length of time that the cats were on treatment before post-treatment sample was 28 days. Total T4, heart rate, SBP, and PCV all decreased and body weight and creatinine concentrations increased once euthyroidism was established. In addition, NT-proBNP significantly declined, but no change in NT-proANP concentrations was noted. In conclusion, hyperthyroidism has a modest but significant effect on elevating NT-proBNP with little effect on NT-proANP. Therefore, thyroid status should be taken into account when interpreting NT-proBNP results. [GO]

See also: Singletary GE, Rush JE, Fox PR, Stepien RL and Oyama MA. Effect of NT-pro-BNP assay on accuracy and confidence of general practitioners in diagnosing heart failure or respiratory disease in cats with respiratory signs. J Vet Intern Med. 2012; 26: 542-6.

Related blog articles:
Biochemical testing for feline heart disease (March 2009)
Cardiac biomarkers in feline heart disease (July 2011)

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+
Read More


Monday, March 30, 2009

Biochemical Testing for Feline Heart Disease

Zimmering, T. M., F. Meneses, et al. (2009). "Measurement of N-terminal proatrial natriuretic peptide in plasma of cats with and without cardiomyopathy." American Journal of Veterinary Research 70(2): 216-222.

Nt-proANP is a natriuretic peptide produced in the cardiac muscle cells of the atria. In humans, ANP concentrations are used to distinguish people with chronic heart failure and monitor progression of the disease, survivability, and the efficacy of cardiac interventions. Two recent studies in cats indicated that plasma ANP concentrations were higher in cats with cardiomyopathy (CM) than in healthy cats. This study looked at 43 cats that were divided into three groups: control cats, cats with cardiomyopathy without congestive heart failure (CM without CHF), and cats with cardiomyopathy with congestive heart failure (CM with CHF). All cats had a physical examination, assessment of clinicopathologic variables that included plasma thyroxine concentration, thoracic radiography, and echocardiography. Each cat was assigned to one of the three groups based on results of these findings. A blood sample was taken from all 43 cats for a plasma Nt-proANP concentration using a human ELISA test kit. The first goal of the study was to determine whether Nt-proANP concentrations in cats with CM differ from concentrations in healthy cats. A second goal was to determine if there was a difference in values between cats with CM and no CHF from those cats that had CM with CHF. The results showed significant difference in Nt-proANP concentrations between the control cats that were healthy and the group with CM without CHF. The values were much higher in those cats assessed with CM only. The cats with CM with CHF had even significantly higher concentrations of Nt-proANP than the elevated values noted for the cats with CM and no CHF. Nt-proANP measurement could aid in the assessment of cats with cardiomyopathy and might be useful as a screening marker for the disease. The assay also has the potential for distinguishing between cats with CM without CHF and cats with CM and CHF. [VT]
>> PubMed Abstract

Related articles:
Connolly, D. J., R. J. Soares Magalhaes, et al. (2008). "Circulating natriuretic peptides in cats with heart disease." J Vet Intern Med 22(1): 96-105.
>> PubMed Abstract

Biondo, A. W., E. J. Ehrhart, et al. (2003). "Immunohistochemistry of atrial and brain natriuretic peptides in control cats and cats with hypertrophic cardiomyopathy." Vet Pathol 40(5): 501-6.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Zimmering, T. M., F. Meneses, et al. (2009). "Measurement of N-terminal proatrial natriuretic peptide in plasma of cats with and without cardiomyopathy." American Journal of Veterinary Research 70(2): 216-222.

Nt-proANP is a natriuretic peptide produced in the cardiac muscle cells of the atria. In humans, ANP concentrations are used to distinguish people with chronic heart failure and monitor progression of the disease, survivability, and the efficacy of cardiac interventions. Two recent studies in cats indicated that plasma ANP concentrations were higher in cats with cardiomyopathy (CM) than in healthy cats. This study looked at 43 cats that were divided into three groups: control cats, cats with cardiomyopathy without congestive heart failure (CM without CHF), and cats with cardiomyopathy with congestive heart failure (CM with CHF). All cats had a physical examination, assessment of clinicopathologic variables that included plasma thyroxine concentration, thoracic radiography, and echocardiography. Each cat was assigned to one of the three groups based on results of these findings. A blood sample was taken from all 43 cats for a plasma Nt-proANP concentration using a human ELISA test kit. The first goal of the study was to determine whether Nt-proANP concentrations in cats with CM differ from concentrations in healthy cats. A second goal was to determine if there was a difference in values between cats with CM and no CHF from those cats that had CM with CHF. The results showed significant difference in Nt-proANP concentrations between the control cats that were healthy and the group with CM without CHF. The values were much higher in those cats assessed with CM only. The cats with CM with CHF had even significantly higher concentrations of Nt-proANP than the elevated values noted for the cats with CM and no CHF. Nt-proANP measurement could aid in the assessment of cats with cardiomyopathy and might be useful as a screening marker for the disease. The assay also has the potential for distinguishing between cats with CM without CHF and cats with CM and CHF. [VT]
>> PubMed Abstract

Related articles:
Connolly, D. J., R. J. Soares Magalhaes, et al. (2008). "Circulating natriuretic peptides in cats with heart disease." J Vet Intern Med 22(1): 96-105.
>> PubMed Abstract

Biondo, A. W., E. J. Ehrhart, et al. (2003). "Immunohistochemistry of atrial and brain natriuretic peptides in control cats and cats with hypertrophic cardiomyopathy." Vet Pathol 40(5): 501-6.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Read More