Taniguchi Ayumu, Kawamura Masataka, Sakai Shinsuke, Kimura-Ohba Shihoko, Tanaka Yoko, Fukae Shota, Tanaka Ryo, Nakazawa Shigeaki, Yamanaka Kazuaki, Horio Masaru, Takahara Shiro, Nonomura Norio, Isaka Yoshitaka, Imamura Ryoichi, Kimura Tomonori
Department of Urology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
KAGAMI Project, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Osaka, Japan.
Kidney Int Rep. 2023 Mar 21;8(6):1192-1200. doi: 10.1016/j.ekir.2023.03.009. eCollection 2023 Jun.
An ideal endogenous molecule for measuring glomerular filtration rate (GFR) is still unknown. However, a rare enantiomer of serine, d-serine, is useful in GFR measurement. This study explored the potential of other d-amino acids for kidney function assessment.
This was a cross-sectional observational study of 207 living kidney transplant donors and recipients, for whom GFR was measured using clearance of inulin (C-in). Associations between levels of d-amino acids and GFR were analyzed using multivariate factor analysis. Fractional excretion (FE), a ratio of the clearance of a substance to C-in as a standard molecule, was calculated to monitor the excretion ratio after glomerular filtration. Dissociation from an ideal FE of 100% was assessed as a bias. Proportional bias against C-in was calculated using Deming regression.
Multivariate analysis identified the blood level of d-asparagine to reflect GFR. Means of blood d-asparagine and clearance of d-asparagine (C-d-Asn) were 0.21 μM and 65.0 ml/min per 1.73 m, respectively. Inulin-based FE (FE) of d-asparagine was 98.67% (95% confidence interval [CI]: 96.43-100.90%) and less biased than those of known GFR markers, such as FE of creatinine (147.93 [145.39-150.46]; < 0.001) and d-serine (84.84 [83.22-86.46]; < 0.001). A proportional bias of C-d-Asn to C-in was -7.8% (95% CI, -14.5 to -0.6%), which was minor compared to those of clearance of creatinine (-34.5% [-37.9 to -31.0%]) and d-serine (21.2% [13.9-28.9]).
D-Asparagine acts similar to inulin in the kidney. Therefore, d-asparagine is an ideal endogenous molecule that can be used for GFR measurement.
用于测量肾小球滤过率（GFR）的理想内源性分子仍然未知。然而，丝氨酸的一种罕见对映体，即d-丝氨酸，在GFR测量中很有用。本研究探讨了其他d-氨基酸在肾功能评估中的潜力。
这是一项对207名活体肾移植供体和受体的横断面观察性研究，通过菊粉清除率（C-in）测量他们的GFR。使用多因素分析来分析d-氨基酸水平与GFR之间的关联。计算分数排泄率（FE），即一种物质的清除率与作为标准分子的C-in的比值，以监测肾小球滤过后的排泄率。将与理想FE值100%的偏差评估为偏差。使用Deming回归计算相对于C-in的比例偏差。
多因素分析确定d-天冬酰胺的血液水平可反映GFR。血液中d-天冬酰胺的平均值和d-天冬酰胺清除率（C-d-Asn）分别为0.21 μM和每1.73平方米65.0 ml/分钟。d-天冬酰胺的基于菊粉的FE（FE）为98.67%（95%置信区间[CI]：96.43 - 100.90%），且偏差小于已知GFR标志物，如肌酐的FE（147.93 [145.39 - 150.46]；< 0.001）和d-丝氨酸的FE（84.84 [83.22 - 86.46]；< 0.001）。C-d-Asn相对于C-in的比例偏差为 -7.8%（95% CI，-14.5至-0.6%），与肌酐清除率（-34.5% [-37.9至-31.0%]）和d-丝氨酸清除率（21.2% [13.9 - 28.9]）相比，该偏差较小。
d-天冬酰胺在肾脏中的作用类似于菊粉。因此，d-天冬酰胺是一种可用于测量GFR的理想内源性分子。
