Electrophoretic patterns of proteinuria in feline spontaneous chronic kidney disease.

OBJECTIVES: The purpose of this study was to describe the electrophoretic patterns of proteinuria in cats at risk of and cats with chronic kidney disease (CKD), and to investigate whether the presence of high-molecular-weight (HMW) and low-molecular-weight (LMW) proteins were associated with CKD, proteinuria and/or disease progression. METHODS: Healthy cats at risk of developing renal disease (n = 17) and cats affected with CKD at different stages (n = 22) were prospectively enrolled and sampled over time. Seventy urine samples were included and assayed with a commercially available sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) method. Each sample (gel lane) was inspected to identify albumin, HMW and LMW proteins, and an electrophoretic pattern (albuminuria, glomerular, tubular, mixed or negative) was assigned accordingly. Fisher's exact test was used to assess the distribution of HMW and LMW proteins in cats grouped according to International Renal Interest Society stage and to the magnitude of proteinuria, and to assess if HMW and LMW proteins at the time of inclusion were associated with the development and progression of CKD. RESULTS: In samples of cats at risk, the most common pattern was glomerular (84.6%); glomerular pattern was also common in cats with CKD (54.2%), although mixed proteinuria and tubular proteinuria were also present (29.5% and 11.4%, respectively). The presence of LMW proteins was associated with CKD (P <0.0001) and to a urine protein:creatinine ratio >0.2 (P = 0.025). Both HMW and LMW proteins were not associated with progression of CKD within 6 months (n = 14). CONCLUSIONS AND RELEVANCE: Our results showed that HMW proteinuria is common in healthy cats at risk of developing CKD, although the pathological significance needs to be confirmed. The detection of LMW proteins in urine of cats suspected to be affected by CKD, especially in non-azotaemic, non-proteinuric or borderline proteinuric cats, suggests the presence of kidney damage.

Macroamilasemia en una niña de 13 años / Macroamylasemia in a thirteen-year-old girl

La Macroamilasemia es una alteración bioquímica caracterizada por la presencia en la sangre de un complejo macromolecular formado por amilasa ligada a las inmunoglobulinas séricas. Suele cursar con hiperamilasemia, lo que plantea el diagnóstico diferencial con la pancreatitis. Aunque no es excepcional en la edad adulta, se han descrito muy pocos casos en la edad pediátrica. Reportamos un caso clínico de una paciente de 13 años de edad, con antecedentes de agenesia renal izquierda congénita y un cuadro clínico de dolor abdominal recidivante. Los exámenes complementarios evidenciaron hiperamilasemia persistente, con valores normales de amilasuria, así como de tripsina inmunoreactiva y lipasa séricas. El cociente de aclaramiento amilasa-creatinina no estaba elevado. Otros exámenes complementarios para investigar las posibles causas del dolor abdominal, incluida la pancreatitis, fueron normales o negativos. La ultrasonografía y TAC abdominales no evidenciaron alteraciones pancreáticas ni otras lesiones, a excepción de la agenesia renal izquierda y la hiperplasia compensadora del riñón derecho. El diagnóstico de macroamilasemia se confirmó por electroforesis en gel de agarosa y mediante precipitación con polietilenglicol. Al ser la macroamilasemia un trastorno benigno, su identificación como la causa de la hiperamilasemia es esencial para evitar un diagnóstico y tratamientos erróneos (AU)