OBJECTIVETo explore the effects of methylglyoxal on endothelia cell migration.

METHODSHuman umbilical vein endothelial cells (HUVECs) were stimulated by serial concentrations of methylglyoxal (MGO, 0, 25, 50, 100 and 200 µmol/L) for 24 h, and the cell migration was assessed by scratch wound and Transwell assay. The expression of integrin β3 in the treated cells was examined by immunoblotting, and the effect of an anti-β3 antibody, LM609, on cell migration was investigated.

RESULTSMethylglyoxal significantly inhibited HUVEC migration in a concentration-dependent manner (P<0.05). Methylglyoxal decreased the expression of integrin β3 in a time- and concentration-dependent manner (P<0.05). LM609 also significantly inhibited HUVEC migration (P<0.05).

CONCLUSIONMethylglyoxal inhibits HUVEC migration in vitro by down-regulating integrin β3 expression.

Cell Movement ; drug effects ; Cells, Cultured ; Down-Regulation ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Integrin beta3 ; metabolism ; Pyruvaldehyde ; pharmacology

The formation of advanced glycation end products (AGEs) has been considered to be a potential causative factor of injury to lens epithelial cells (LECs). Damage of LECs is believed to contribute to cataract formation. The purpose of this study was to investigate the cytotoxic effect of AGEs on LECs both in vitro and in vivo. We examined the accumulation of argpyrimidine, a methylglyoxal-derived AGE, and the expression of apoptosis-related molecules including nuclear factor-kappaB (NF-kappaB), Bax, and Bcl-2 in the human LEC line HLE-B3 and in cataractous lenses of Zucker diabetic fatty (ZDF) rats, an animal model of type 2 diabetes. In cataractous lenses from twenty-one-week-old ZDF rats, LEC apoptosis was markedly increased, and the accumulation of argpyrimidine as well as subsequent activation of NF-kappaB in LECs were significantly enhanced. The ratio of Bax to Bcl-2 protein levels was also increased. In addition, the accumulation of argpyrimidine triggered apoptosis in methylglyoxal-treated HLE-B3 cells. However, the presence of pyridoxamine (an AGEs inhibitor) and pyrrolidine dithiocarbamate (a NF-kappaB inhibitor) prevented apoptosis in HLE-B3 cells through the inhibition of argpyrimidine formation and the blockage of NF-kappaB nuclear translocalization, respectively. These results suggest that the cellular accumulation of argpyrimidine in LECs is NF-kappaB-dependent and pro-apoptotic.
Animals ; Apoptosis/*drug effects ; Cell Line ; Epithelial Cells/*cytology/*drug effects ; Glycosylation End Products, Advanced/*pharmacology ; Lens, Crystalline/*cytology ; Male ; Ornithine/*analogs & derivatives/pharmacology ; Pyrimidines/*pharmacology ; Pyruvaldehyde/*chemistry ; Rats

OBJECTIVETo evaluate the effects of aminoguanidine on methylglyoxal-mediated oxygen-glucose deprivation (OGD) injury in the cultured human brain microvascular endothelial cells (HBMEC).

METHODSCultured HBMEC cells were pretreated with methylglyoxal before oxygen-glucose deprivation injury. Cell vitality was determined by MTT method, cell mortality was assessed by LDH release method, cell apoptosis was examined by Annexin V/PI formation method, and the advanced glycation end products (AGEs) were detected by Western-blot.

RESULTSMethylglyoxal induced HBMEC injury in a dose-dependent manner. At 2 mmol/L of methylglyoxal, the cell viability was 56.1% when methylglyoxal-pretreated cells exposed to oxygen-glucose deprivation, the cell inhibition rate was 90.0%. Aminoguanidine (1 mmol/L) inhibited methylglyoxal and OGD induced LDH release and Annexin V/PI formation. Furthermore, aminoguanidine (1 mmol/L) also decreased advanced glycation end products (AGEs) formation induced by methylglyoxal and oxygen-glucose deprivation.

CONCLUSIONAminoguanidine protected methylglyoxal mediated-oxygen-glucose deprivation injury in the cultured HBMEC, which may be associated with anti-glycation activity.

Apoptosis ; drug effects ; Cell Hypoxia ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Drug Antagonism ; Endothelial Cells ; drug effects ; metabolism ; pathology ; Endothelium, Vascular ; cytology ; Glycation End Products, Advanced ; metabolism ; Guanidines ; pharmacology ; Humans ; Pyruvaldehyde ; pharmacology

One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive -dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 micrometer) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kB activation and increased caspase- 3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF- kB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kB are involved in the apoptotic process.
Acetylcysteine/pharmacology ; Animals ; *Apoptosis ; Caspases/metabolism ; Cattle ; Cell Death ; Cell Survival ; DNA Fragmentation ; Dose-Response Relationship, Drug ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Glucose/metabolism ; NF-kappa B/metabolism ; Nucleosomes/metabolism ; Oxidative Stress ; Pericytes/*drug effects ; Pyruvaldehyde/*pharmacology ; *Reactive Oxygen Species ; Retina/cytology/*drug effects