Dihydrolipoic acid protects pancreatic islet cells from inflammatory attack.
In vitro models of pancreatic islet cell inflammation are the lysis of isolated islet cells by activated macrophages or by oxygen radicals released by the endothelial enzyme xanthine oxidase. Dihydrolipoic acid protected islet cells in both systems by different modes of action. Macrophage cytotoxicity towards islet cells, which is nitric-oxide-mediated, was suppressed by 2 h of preincubation of macrophages with lipoic acid. Similarly, 2 h of preincubation sufficed to protect islet cells against enzymatically produced oxygen radicals. Dihydrolipoic acid was found by chemiluminescence assay to scavenge directly such radicals. In macrophages dihydrolipoic acid suppressed the production of nitrite as a measure of nitric oxide release. These results suggest that dihydrolipoic acid is an anti-inflammatory agent which at the same time interferes with nitric oxide release from inflammatory macrophages and protects target cells from oxygen radical attack.
Burkart
V
V
Diabetes Research Institute, University of Düsseldorf, Germany.
Koike
T
T
Brenner
H H
HH
Imai
Y
Y
Kolb
H
H
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002478:Cells, Cultured; D005609:Free Radicals / Q000378:metabolism; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008163:Luminescent Measurements; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010529:Peritoneal Cavity; D051381:Rats; D017208:Rats, Wistar; D008063:Thioctic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D005609:Free Radicals; D007042:Hypoxanthines; D009573:Nitrites; D019271:Hypoxanthine; D009569:Nitric Oxide; D008063:Thioctic Acid; C015144:dihydrolipoic acid; D014969:Xanthine Oxidase