Urinary excretion of liver type fatty acid binding protein accurately reflects the degree of tubulointerstitial damage.
To investigate the relationship between liver-type fatty acid-binding protein (L-FABP), a biomarker of chronic kidney disease, in the kidney and the degree of tubulointerstitial damage, folic acid (FA)-induced nephropathy was studied in a mouse model system. As renal L-FABP is not expressed in wild-type mice, human L-FABP (hL-FABP) transgenic mice were used in this study. hL-FABP is expressed in the renal proximal tubules of the transgenic mice that were injected intraperitoneally with FA in NaHCO3 (the FA group) or only NaHCO3 (the control group) and oral saline solution daily during the experimental period. The FA group developed severe tubulointerstitial damage with the infiltration of macrophages and the deposition of type I collagen on days 3 and 7 and recovered to the control level on day 14. The gene and protein expression levels of hL-FABP in the kidney were significantly enhanced on days 3 and 7. Urinary hL-FABP in the FA group was elevated on days 3 and 7 and decreased to the control level on day 14. The protein expression levels of hL-FABP in both the kidney and urine significantly correlated with the degree of tubulointerstitial damage, the infiltration of macrophages, and the deposition of type I collagen. In conclusion, renal expression and urinary excretion of hL-FABP significantly reflected the severity of tubulointerstitial damage in FA-induced nephropathy.
Yokoyama
Takeshi
T
Prof. of Medicine, Nephrology and Hypertension, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-Ku, Kawasaki 216-8511, Japan.
Kamijo-Ikemori
Atsuko
A
Sugaya
Takeshi
T
Hoshino
Seiko
S
Yasuda
Takashi
T
Kimura
Kenjiro
K
D000818:Animals; D015153:Blotting, Western; D018932:Chemokine CCL2 / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007674:Kidney Diseases / Q000378:metabolism* / Q000473:pathology*; D007684:Kidney Tubules / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008822:Mice, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018932:Chemokine CCL2; C493319:FABP1 protein, human; D050556:Fatty Acid-Binding Proteins