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Biomarkers of feline hypertension

Bijsmans ES, Jepson RE, et al. Plasma N-Terminal Probrain Natriuretic Peptide, Vascular Endothelial Growth Factor, and Cardiac Troponin I as Novel Biomarkers of Hypertensive Disease and Target Organ Damage in Cats. J Vet Intern Med. 2017;31:650–660

Damage to body tissues often leads to release of molecules specific to the affected tissue.  These molecules are sometimes useful as biomarkers of damage, with the added bonus that changes in the biomarker level may be used to monitor ongoing tissue damage or resolution of tissue damage.  In cases of hypertension, damage to endothelial cells can lead to release of vascular endothelial growth factor (VEGF).  Damage to cardiomyocytes secondary to hypertension may lead to release of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and/or cardiac troponin I (cTn1).  Renal tubular damage related to hypertension can lead to proteinuria, and as such, the urine protein:creatinine ratio (UPC) may be considered as a possible biomarker of hypertension.  Monitoring these parameters in humans with hypertension can be beneficial in diagnosis and management of the condition.

The authors set out to determine if substances VEGF, NT-proBNP, cTnI and/or UPC could be used as biomarkers of hypertension in cats with and without ocular target organ damage (TOD).  They also sought to assess whether the levels of these biomarkers might be informative about hypertension control measures.

The study was designed as both retrospective cross-sectional and retrospective longitudinal.  Four groups were included in the cross-sectional portion of the study: azotemic cats with chronic kidney disease (CKD), healthy geriatric cats, hypertensive cats with evidence of ocular TOD and hypertensive cats without evidence of ocular TOD.  The longitudinal portion of the study looked at only the hypertensive groups (with and without ocular TOD).

Statistically significant elevations were found in VGEF levels in cats with ocular TOD compared to all other groups.  Cats with ocular TOD had significantly higher NT-proBNP than healthy cats.   Healthy cats were found to have significantly lower cTn1 than all other groups.  Despite the statistically significant changes noted, assessment of receiver operator characteristic curves indicated that none of the biomarkers met the criteria to function as diagnostic tests for either hypertension or hypertension-related ocular TOD.

The authors conclude that VGEF, NT-proBNP and cTn1 would not function as useful tests in the diagnosis of feline hypertension.  The authors concluded that at this time, the diagnosis of feline hypertension continues to rely upon the observation of repeated elevations in systolic blood pressure in combination with evidence of end target organ damage. (KSD)

See also:
Fox PR, Rush JE, et al. Multicenter evaluation of plasma N-terminal probrain natriuretic peptide (NT-pro BNP) as a biochemical screening test for asymptomatic (occult) cardiomyopathy in cats. J Vet Intern Med. 2011 Sep-Oct;25(5):1010-6.