Publicação
Plasma and urinary metanephrine and normetanephrine in healthy cats : a pilot study
| Resumo: | PLASMA AND URINARY METANEPHRINE AND NORMETANEPHRINE IN HEALTHY CATS – A PILOT STUDY - Feline pheochromocytoma (PCC) is considered to be rare and literature is limited to a few case-reports. In humans and dogs, biochemical diagnosis of a PCC is based on the measurements of plasma (PL) and/or urinary (U) metanephrine (MN) and normetanephrine (NMN) but little is known about these biomarkers in cats. This pilot study aims to evaluate the feasibility of PL-MN/NMN and U-MN/NMN measurement in cats, using liquid chromatography with tandem mass spectrometry (LC-MSMS). Furthermore, it intends to assess the U-MN/NMN stability under refrigeration (+4ºC) for 24h. A cross-sectional pilot study was conducted, using a group of 10 healthy cats, with ages ranging from 4 to 10 years. After sampling, EDTA-plasma and urine samples were stored at - 80ºC until measurement of PL-MN/NMN and U-MN/NMN. For each cat, an additional urine sample was refrigerated (UR) for 24h before storage at -80ºC. Leftover plasma and urine samples collected from a cat with a confirmed diagnosis of PCC (PheoCat) were also submitted for analysis. Urinary creatinine (Creat) was measured in the same spot urine samples in order to calculate U-MN/Creat and U-NMN/Creat ratios. With regard to the population of healthy adult cats, the PL-MN and PL-NMN median values were 2.73nmol/L (IQR=2.37) and 7.02nmol/L (IQR=5.2), respectively. U-MN/Creat and U-NMN/Creat ratios had medians of 70μg/g (IQR=70) and 139μg/g (IQR=77), respectively. Results obtained from the PheoCat revealed a PL-MN of 3.68nmol/L, PL-NMN of 66.27nmol/L, U-MN/Creat ratio of 179 μg/g and U-NMN/Creat ratio of 1262 μg/g. None of these values overlapped with the medians obtained from the healthy cats. The U-MN/NMN proved to be stable under refrigeration for 24h, as there was no statistical difference between U-MN vs URMN and U-NMN vs UR-NMN (p= 0.329 and p= 0.813, respectively). This is the first study reporting both PL-MN/NMN and U-MN/NMN measurements by LC-MS-MS in adult healthy cats and will contribute to the biochemical diagnosis of feline PCC in the future. The PheoCat had a substantial increase in all the measured parameters, particularly PL-NMN and U-NMN/Creat ratio, when compared to the healthy cats, highlighting the clinical applicability of these biomarkers in the diagnosis of PCC in cats. |
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| Autores principais: | Alexandre, Maria Teresa Carneiro Prego Marques |
| Assunto: | Pheochromocytoma Plasma and urinary metanephrines Liquid chromatography with tandem mass spectrometry Healthy cats Feocromocitoma Metanefrinas plasmáticas e urinárias Cromatografia líquida com espectrometria de massa em tandem Gatos saudáveis |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | PLASMA AND URINARY METANEPHRINE AND NORMETANEPHRINE IN HEALTHY CATS – A PILOT STUDY - Feline pheochromocytoma (PCC) is considered to be rare and literature is limited to a few case-reports. In humans and dogs, biochemical diagnosis of a PCC is based on the measurements of plasma (PL) and/or urinary (U) metanephrine (MN) and normetanephrine (NMN) but little is known about these biomarkers in cats. This pilot study aims to evaluate the feasibility of PL-MN/NMN and U-MN/NMN measurement in cats, using liquid chromatography with tandem mass spectrometry (LC-MSMS). Furthermore, it intends to assess the U-MN/NMN stability under refrigeration (+4ºC) for 24h. A cross-sectional pilot study was conducted, using a group of 10 healthy cats, with ages ranging from 4 to 10 years. After sampling, EDTA-plasma and urine samples were stored at - 80ºC until measurement of PL-MN/NMN and U-MN/NMN. For each cat, an additional urine sample was refrigerated (UR) for 24h before storage at -80ºC. Leftover plasma and urine samples collected from a cat with a confirmed diagnosis of PCC (PheoCat) were also submitted for analysis. Urinary creatinine (Creat) was measured in the same spot urine samples in order to calculate U-MN/Creat and U-NMN/Creat ratios. With regard to the population of healthy adult cats, the PL-MN and PL-NMN median values were 2.73nmol/L (IQR=2.37) and 7.02nmol/L (IQR=5.2), respectively. U-MN/Creat and U-NMN/Creat ratios had medians of 70μg/g (IQR=70) and 139μg/g (IQR=77), respectively. Results obtained from the PheoCat revealed a PL-MN of 3.68nmol/L, PL-NMN of 66.27nmol/L, U-MN/Creat ratio of 179 μg/g and U-NMN/Creat ratio of 1262 μg/g. None of these values overlapped with the medians obtained from the healthy cats. The U-MN/NMN proved to be stable under refrigeration for 24h, as there was no statistical difference between U-MN vs URMN and U-NMN vs UR-NMN (p= 0.329 and p= 0.813, respectively). This is the first study reporting both PL-MN/NMN and U-MN/NMN measurements by LC-MS-MS in adult healthy cats and will contribute to the biochemical diagnosis of feline PCC in the future. The PheoCat had a substantial increase in all the measured parameters, particularly PL-NMN and U-NMN/Creat ratio, when compared to the healthy cats, highlighting the clinical applicability of these biomarkers in the diagnosis of PCC in cats. |
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