Interaction of glucose and long chain fatty acids (C18) on antioxidant defences and free radical damage in porcine vascular smooth muscle cells in vitro.
OBJECTIVE
Abnormalities of glucose and fatty acid metabolism in diabetes are believed to contribute to the development of oxidative stress and the long term vascular complications of the disease; therefore the interactions of glucose and long chain fatty acids on free radical damage and endogenous antioxidant defences were investigated in vascular smooth muscle cells.


METHODS
Porcine vascular smooth muscle cells were cultured in 5 mmol/l or 25 mmol/l glucose for 10 days. Fatty acids, stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and alpha-linolenic acid (18:3) were added with defatted bovine serum albumin as a carrier for the final three days.


RESULTS
Glucose (25 mmol/l) alone caused oxidative stress in the cells as evidenced by free radical-mediated damage to DNA, lipids, and proteins. The addition of fatty acids (0.2 mmol/l) altered the profile of free radical damage; the response was J-shaped with respect to the degree of unsaturation of each acid, and oleic acid was associated with least damage. At a lower concentration alpha-linolenic acid (0.01 mmol/l) was markedly different in that, when added to 25 mmol/l glucose it resulted in a decrease in free radical damage to DNA, lipids and proteins. This was accompanied by a marked increase in antioxidant and glutathione concentrations as well as by increased gene expression is of gamma-glutamylcysteine synthetase, the rate-limiting enzyme in glutathione synthesis.


CONCLUSIONS
The results clearly show that glucose and fatty acids interact in the production of oxidative stress in vascular smooth muscle cells.
Hamilton
J S
JS
Department of Clinical Biochemistry, Queen's University, Belfast, UK.
Powell
L A
LA
McMaster
C
C
McMaster
D
D
Trimble
E R
ER
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D005721:Glutamate-Cysteine Ligase / Q000235:genetics / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010084:Oxidation-Reduction / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013552:Swine
D000975:Antioxidants; D005227:Fatty Acids; D005609:Free Radicals; D011506:Proteins; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; D005947:Glucose