尿中逸脱酵素・蛋白に関する研究 第3報: 非イオン性造影剤の尿中逸脱酵素・蛋白に及ぼす影響について

Abstract

通常行われている尿路造影法に非イオン性造影剤(iohexol)を用い, 検査前後で尿中逸脱酵素・蛋白がどのような変化を示すかにつき検討した.正常な腎機能を有する9例を対象とし, DIPにて注入スピード10 ml/min, 総投与量100 ml (2.5 ml以下/kg)で静注した.投与前後の尿を採取し, 糸球体濾過能の指標としてアルブミンを, brush-border酵素としてγ-GTPを, lysosomal酵素としてNAGを, 尿細管性蛋白尿の指標としてα1MGおよびβ2MGを測定し, 各酵素と蛋白の尿中排泄量を尿中クレアチニン量と比較検定した.DIP後γ-GTPとNAGの尿中排泄量は有意(p<0.001, 0.02)に増加した.α1MGおよびβ2MGは有意に変化せず, アルブミンの変化は少量であった.今回の検討から, 非イオン性, 低浸透圧性造影剤であるiohexolは尿細管障害が少なく, brush-border酵素であるγ-GTPとlysosomal酵素のNAGは尿細管障害の良い指標となると考えられた

Renal toxicity of non-ionic contrast medium (iohexol) for drip infused pyelography (DIP) was studied in a randomized trial of nine patients with normal renal function. Urine samples were collected before and immediately after DIP, and analyzed for albumin, an index of glomerular permeability; gamma-glutamyl transpeptidase (gamma-GTP), a brush-border enzyme; N-acetyl-beta-glucosaminidase (NAG), a lysosomal enzyme; alpha 1 microglobulin (alpha 1MG) and beta 2 microglobulin (beta 2MG), an index to tubular proteinuria; and creatinine. The urinary excretion of enzymes and proteins was compared with urinary creatinine. Urinary excretion of gamma-GTP and NAG increased significantly (P less than 0.001, 0.02) after DIP. Urinary alpha 1 MG and beta 2-MG did not change significantly. The change of urinary albumin was mild. Our data suggest that non-ionic, low osmolal radiocontrast medium ioheol shows a lower renal tubular toxicity, and the brush-border enzyme gamma-GTP and lysosomal enzyme NAG are considered as a good index for renal tubular damage.