In vitro-prepared advanced glycation end-products and the modulating potential of their low-molecular weight degradation products in IRPTC-A rat proximal-tubular derived kidney epithelial cell line.
Low-molecular advanced glycation end-products (AGEs)-degradation products resulting from a proteolysis of tissue or circulating AGEs represent up to 80% of AGE plasma immunoreactivity. These AGE peptides contribute to the dramatic increase in AGE levels in end-stage renal disease even in the absence of diabetes. Because glomerular filtered AGE-degradation products may accumulate within intracellular compartments of proximal tubular epithelial cells, we investigated whether there is a pathway potentially mediating damaging effects of AGE-degradation products by perturbation of the function of the tubuloepithelium. Proximal tubular-derived rat kidney cells (IRPTC) were incubated with high-molecular AGEs highly modified by incubation of bovine serum albumin (BSA) with glucose for 50 days in vitro, and with low-molecular AGE-degradation products derived from proteolytic cleavage and isolated in the molecular range between 1 and 30 kDa. The proliferation of IRPTC (3H-thymidine incorporation) was reduced to 89+/-1% and 69+/-2% after 24 hr of incubation with BSA-AGE and BSA-AGE-degradation products, respectively. The cell viability of IRPTC was reduced significantly to 59+/-15% and 31+/-13% after 144 hr of incubation with BSA-AGE and BSA-AGE-degradation products, respectively. Conditioned media obtained from IRPTC incubated for 72 hr with BSA-AGE and its degradation products increased the proliferation rate of renal fibroblasts (RFb) to 222+/-24% and 449+/-40%, respectively. Incubation of IRPTC with BSA-AGE-degradation products increased the expression of endothelin-1 (ET-1) mRNA to 210% after 1 hr; the expression of platelet-derived growth factor-B (PDGF-B) mRNA reached 184% after 2 hr. Regarding the toxicity of AGEs to the kidney, low-molecular weight AGE-degradation products possibly form an individual fraction with a comparatively higher toxic potential.
Deuther-Conrad
W
W
Department of Internal Medicin IV, Friedrich Schiller University Jena, Germany.
Franke
S
S
Henle
T
T
Sommer
M
M
Stein
G
G
D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D018932:Chemokine CCL2 / Q000235:genetics; D017077:Culture Media, Conditioned; D019332:Endothelin-1 / Q000235:genetics; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D017127:Glycation End Products, Advanced / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity*; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008970:Molecular Weight; D010982:Platelet-Derived Growth Factor / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012710:Serum Albumin, Bovine / Q000378:metabolism
D018932:Chemokine CCL2; D017077:Culture Media, Conditioned; D019332:Endothelin-1; D017127:Glycation End Products, Advanced; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D012710:Serum Albumin, Bovine