β2マイクログロブリンの尿中排泄動態からみた腎摘後の残腎尿細管における代償性機能変化の検討

Abstract

41例の腎摘例につき, 手術前後の血中と尿中β2マイクログロブリン(β2MG), クレアチニン・クリアランスなどを測定し, ことにβ2MGの糸球体濾過量, 尿細管再吸収量, 尿中排出量の変化を検討した.1)腎摘後血中クレアチニンとβ2MGは有意に増加し, またクレアチニン・クリアランスは術直後いったん低下し, 第2～4病日には回復した.2)糸球体における濾過量は腎摘後低下したが, 第2～4病日には術前の両腎の和の値を上回った.一方尿細管における再吸収量は腎摘後低下し, 第5～8病日になって術前値を上回った.その結果, 尿中排出量は第0～4病日に著明に増加した.この増加はいわゆる尿細管障害によるものではなく, 残腎ネフロンのGlomerulo-tubular-adaptationの一過程としてとらえられた

Serum and urinary beta 2-microglobulin (S-, U-beta 2MG), and creatinine clearance (C-cr) were examined in 41 nephrectomy cases, and changes in glomerular and tubular handling of beta 2MG such as filtered beta 2MG (Fil-beta 2MG), reabsorption of beta 2MG (Reab-beta 2MG) and fractional excretion of beta 2MG (FE-beta 2MG) were studied. Serum creatinine (S-cr) and S-beta 2MG increased significantly after nephrectomy. C-cr decreased immediately after nephrectomy (80%), but recovered up to 87% in 2 to 4 days postoperatively. Fil-beta 2MG decreased immediately after nephrectomy, but increased up to more than the preoperative level in 2 to 4 days postoperatively. On the other hand, Reab-beta 2MG decreased significantly immediately after nephrectomy, and it took 5 to 8 days until recovery. Consequently, urinary excretion of beta 2MG (Ex-beta 2MG) and FE-beta 2MG increased significantly 0 to 4 days postoperatively. These increases in Ex-beta 2MG and FE-beta 2MG were much higher than those seen in diabetic nephropathy, cadmium nephropathy and Cis-diamminedichloroplatinum (II) (CDDP) intoxication, and were not due to drug intoxication such as general anesthesia or antibiotics, but due to glomerulo-tubular unbalance. Clinical data of renal tubular handling of beta 2-microglobulin in cases of interferon therapy or unilateral nephrectomy revealed many interesting aspects of glomerulo-tubular adaptations, and micropuncture study or isolated tubule perfusion study are awaited.