Department of Internal Diseases with Clinic for Horses, Dogs and Cats, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, Pl. Grunwaldzki 47, 50-366 Wrocław, Poland.
Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383 Wroclaw, Poland.
Molecules. 2019 Aug 26;24(17):3088. doi: 10.3390/molecules24173088.
The early asymptomatic stage of glomerular injury is a diagnostic challenge in the course of renal and extra-renal disease, e.g., heart insufficiency. It was found that podocin, a podocyte-specific protein present in the urine, may serve as a biomarker in the diagnosis of glomerular disease in humans and animals including glomerulonephritis, glomerulosclerosis, amyloidosis, or nephropathy. Therefore, there is a need of development of the sensitive and straightforward method of urinary podocin identification. In this work, we report our extended research under the glomerular injury investigation in dogs by application of clinical examination and LC-MS-MRM method in the identification of canine podocin in urine samples. The LC-MS-MRM method is based on the identification of podocin tryptic peptide with the H-AAEILAATPAAVQLR-OH sequence. The model peptide was characterized by the highest ionization efficiency of all the proposed model podocin tryptic peptides in a canine urine sediment according to the LC-MS/MS analysis. The obtained results revealed the presence of the model peptide in 40.9% of dogs with MMVD (active glomerular injury secondary to heart disease = cardiorenal syndrome-CRS) and 33.3% dogs with chronic kidney disease. The potential applicability of the developed methodology in the analysis of podocin in canine urine sediments was confirmed.
肾小球损伤的早期无症状阶段是肾脏和肾脏外疾病（如心力衰竭）过程中的诊断挑战。现已发现，足细胞特异性蛋白 podocin 存在于尿液中，可能作为人类和动物肾小球疾病（包括肾小球肾炎、肾小球硬化症、淀粉样变性或肾病）诊断的生物标志物。因此，需要开发一种灵敏且直接的尿 podocin 鉴定方法。在这项工作中，我们报告了在狗的肾小球损伤研究中的扩展研究结果，应用临床检查和 LC-MS-MRM 方法鉴定尿液样本中的犬 podocin。LC-MS-MRM 方法基于鉴定具有 H-AAEILAATPAAVQLR-OH 序列的 podocin 酶切肽。根据 LC-MS/MS 分析，模型肽是犬尿沉渣中所有提出的模型 podocin 酶切肽中具有最高离子化效率的肽。结果表明，40.9%的 MMVD（继发于心脏病的肾小球活动损伤=心肾综合征-CRS）犬和 33.3%的慢性肾病犬存在该模型肽。该方法在犬尿沉渣中 podocin 分析中的潜在适用性得到了证实。
