N-phenacylthiazolium bromide decreases renal and increases urinary advanced glycation end products excretion without ameliorating diabetic nephropathy in C57BL/6 mice.
OBJECTIVE
Advanced glycation end products (AGE), which form from the non-enzymatic reaction of proteins and sugars, have been implicated in the pathogenesis of diabetic nephropathy. Recently, a compound [N-phenacylthiazolium bromide (PTB)] has been described which cleaves alpha,beta-dicarbonyl compounds. In the present study we used diabetic C57BL/6 mice to determine if PTB altered renal AGE levels and reduced diabetic glomerulosclerosis.


METHODS
Mice with stable hyperglycaemia induced by streptozotocin were given daily subcutaneous injections of either PTB (10 microg/g) or saline for 12 weeks. Renal-collagen bound AGE and urinary AGE-peptides were measured by ELISA using an anti-AGE-RNase antibody. Renal collagen-released Nepsilon(carboxymethyl)lysine (CML) and pentosidine were determined by high pressure liquid chromatography (HPLC). Glomerular lesions (volume and mesangial/total surface area) were evaluated by computer-assisted image analysis. We determined urinary protein/creatinine ratio as a functional parameter. AGE localization was examined by immunohistochemistry using the anti-AGE-RNase antibody.


RESULTS
Renal collagen-bound AGE were decreased and urinary AGE excretion was increased in PTB-treated diabetic mice. However, collagen-released CML and pentosidine were similar in both groups. Glomerular histology and morphometric analysis revealed also no differences between PTB-and saline-treated diabetic mice. The urinary protein/creatinine ratio was unaffected by PTB-treatment. AGE staining by anti-AGE-RNase antibody was present in Bowman's capsules, glomerular basement membranes and cortical tubules. It was decreased in all structures in PTB-treated diabetic mice.


CONCLUSIONS
In summary, PTB decreased renal AGE accumulation but did not ameliorate glomerular lesions or proteinuria. Thus, cleavage of AGE by PTB is not sufficient to prevent development of diabetic nephropathy in C57BL/6 mice.
Schwedler
S B
SB
Laboratory of Renal Cell Biology, Division of Nephrology, Department of Medicine, University of Miami, Miami, FL, USA. Pelleas@t-online.de
Verbeke
P
P
Bakala
H
H
Weiss
M F
MF
Vilar
J
J
Depreux
P
P
Fourmaintraux
E
E
Striker
L J
LJ
Striker
G E
GE
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003094:Collagen / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology* / Q000652:urine; D003928:Diabetic Nephropathies / Q000473:pathology / Q000503:physiopathology* / Q000652:urine; D005260:Female; D005920:Glomerular Mesangium / Q000187:drug effects / Q000473:pathology; D017127:Glycation End Products, Advanced / Q000378:metabolism* / Q000652:urine; D007668:Kidney / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000187:drug effects / Q000473:pathology; D008239:Lysine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011507:Proteinuria; D013844:Thiazoles / Q000494:pharmacology*
D017127:Glycation End Products, Advanced; C101705:N-phenacylthiazolium bromide; D013844:Thiazoles; D003094:Collagen; D001120:Arginine; C062187:pentosidine; D008239:Lysine