Plasma and urinary metanephrine and normetanephrine concentrations using liquid chromatography with tandem mass spectrometry in healthy cats and in a cat with pheochromocytoma

Maria Teresa Prego, Maria Joana Dias, Rui Lemos Ferreira, Salomé Gonçalves, Tiago Dias Domingues, Greet Junius, Evi Van den Steen, Sara Galac, Rodolfo Oliveira Leal*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

BACKGROUND: Pheochromocytoma (PCC) is rare in cats and plasma (PL) and urinary (U) metanephrines (metanephrine [MN]; normetanephrine [NMN]) measurement is rarely described in cats.

OBJECTIVES: We evaluated the utility of PL and U MNs measurement in 10 healthy cats and a cat with a confirmed diagnosis of pheochromocytoma (PheoCat), using liquid chromatography with tandem mass spectrometry (LC-MS-MS).

METHODS: Urine and EDTA PL samples collected from each of the 10 cats and the PheoCat were promptly stored at -80°C and remained frozen until analysis. To evaluate U MNs stability, an additional urine sample collected from the healthy cats was refrigerated for 24 hours before freezing. Urinary creatinine concentration (Creat) was assessed using the same spot urine samples to calculate U MNs-to-creatinine ratios.

RESULTS: The PL-MN and PL-NMN median concentrations of the healthy cats were 2.73 and 7.02 nmol/L, respectively. The median U-MN/Creat and U-NMN/Creat ratios were 70 and 139 μg/g, respectively. The PheoCat had a PL-MN of 3.68 nmol/L, PL-NMN of 66.27 nmol/L, U-MN/Creat of 179 μg/g, and U-NMN/Creat of 1262 μg/g. The PheoCat had markedly increased concentrations of both PL and U MNs when compared to the healthy cats. No significant difference was found between U MNs measured in urine samples that underwent 24 hours of refrigeration in comparison to those that were frozen immediately.

CONCLUSIONS: We report preliminary reference intervals for PL and U MNs in cats using LC-MS-MS and the potential clinical applicability of these biomarkers for the diagnosis of PCC in cats.

Original languageEnglish
Pages (from-to)910-914
Number of pages5
JournalJournal of Veterinary Internal Medicine
Volume37
Issue number3
Early online date13 Apr 2023
DOIs
Publication statusPublished - 1 May 2023

Keywords

  • feline pheochromocytoma
  • healthy cats
  • liquid chromatography with tandem mass spectrometry
  • plasma and urinary metanephrines

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