Speight N, Gates M, Scriven J, Stephenson T, Woolford L
School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, Adelaide, South Australia, 5371, Australia.
Aust Vet J. 2020 Jun;98(6):247-249. doi: 10.1111/avj.12935. Epub 2020 Mar 18.
Oxalate nephrosis is a prevalent renal disease in koalas (Phascolarctos cinereus) of the Mount Lofty Ranges population in South Australia. The symmetric dimethylarginine (SDMA) assay is widely used in companion animals to diagnose renal disease, particularly in the early stages. This study aimed to determine: (1) reference intervals for SDMA in koalas and (2) SDMA values of koalas with oxalate nephrosis. Blood samples were collected from 41 Mount Lofty Ranges koalas euthanased on welfare grounds. Koalas were necropsied and, based on renal histopathology, were classified as unaffected (n = 22) or affected (n = 19) by oxalate nephrosis. Serum or plasma samples were analysed for creatinine, urea and SDMA and urine samples for urine specific gravity (USG). The reference interval for SDMA in unaffected koalas was 2.4-22.9 μg/dL. In koalas with oxalate nephrosis, SDMA was elevated in 74% of cases above the upper limit of the confidence interval. SDMA was elevated in three affected koalas with normal creatinine values. A positive correlation was found between SDMA and creatinine (R = 0.775, P < 0.001) and SDMA and urea (R = 0.580, P < 0.001) and a negative correlation between SDMA and USG (R = -0.495, P = 0.027). In conclusion, SDMA correlates well with other commonly used tests of renal function in koalas and should be included as part of the standard diagnostic process to increase the accuracy of oxalate nephrosis diagnosis in koalas.
草酸肾病是南澳大利亚洛夫蒂岭地区考拉（灰树袋熊）中一种常见的肾脏疾病。对称二甲基精氨酸（SDMA）检测在伴侣动物中广泛用于诊断肾脏疾病，尤其是在早期阶段。本研究旨在确定：（1）考拉SDMA的参考区间，以及（2）患有草酸肾病的考拉的SDMA值。从41只因福利原因实施安乐死的洛夫蒂岭考拉身上采集了血样。对考拉进行了尸检，并根据肾脏组织病理学将其分为未受影响（n = 22）或受草酸肾病影响（n = 19）。对血清或血浆样本进行肌酐、尿素和SDMA分析，对尿液样本进行尿比重（USG）分析。未受影响的考拉SDMA的参考区间为2.4 - 22.9μg/dL。在患有草酸肾病的考拉中，74%的病例SDMA升高至置信区间上限以上。3只肌酐值正常但受影响的考拉SDMA升高。发现SDMA与肌酐（R = 0.775，P < 0.001）、SDMA与尿素（R = 0.580，P < 0.001）呈正相关，SDMA与USG呈负相关（R = -0.495，P = 0.027）。总之，SDMA与考拉其他常用的肾功能检测指标相关性良好，应作为标准诊断流程的一部分纳入，以提高考拉草酸肾病诊断的准确性。
