cardiovascular complications in type 1 or type 2 diabetes.

Relevance of Methylglyoxal Modification of Peroxiredoxin 6 to the Development of Diabetic Complications Tomoko Oya-Ito1, Yuji Naito1, Tomohisa Takagi1, Keisuke Shima2, Yoshito Itoh1, and Toshikazu Yoshikawa1 1Kyoto Prefectural University of Medicine, Japan, 2Shimadzu Corporation, Japan In the diabetic mice, a significant delay in gastric ulcer healing was observed. Methylglyoxal (MG) is a reactive metabolite that modifies proteins and accumulates in diabetes. Peroxiredoxin 6 (Prx6) which functions by facilitating repair of damaged cell membranes via reduction of peroxides was found as the major MG-adducted protein in the diabetic ulcer mice. Peroxidase activity of recombinant Prx6 was inhibited not only by oxidation but also by MG modification. Prx6 contains one conserved reactive cysteine residue Cys-47 in the active site. the decrease in the number of free thiols upon incubation with MG was observed. Mass spectrometry analysis revealed that MG-H1 was generated at Arg-132, which is situated in the catalytic center of peroxidase activity. These results suggest that the decrease in peroxidase activity is due to modification of active-site residues. in vivo, MG-modified Prx6 levels in red blood cells from diabetic patients correlated with both blood glucose and HbA1c levels. in addition, a significant inverse correlation between peroxidase activity and MG-adducted protein levels was observed. These results suggest that MG modification of antioxidant proteins including Prx6 is involved in the delayed wound-healing process in diabetes.

Lipid Phosphate Phosphatase 3 as an Essential Regulator of Vascular Inflammation and Diabetic Restenosis Sumitra Miriyala1, Natalie Hendrix1, Susan Smyth2, Diana Escalante-Alcalde3, and Manikandan Panchatcharam1 1LSU-Health Sciences-Shreveport, United States, 2University of Kentucky, United States, 3Instituto de Fisiología Celular UNAM, Mexico Lysophosphatidic acid (LPA) is a bioactive lipid mediator that is found in abundance in atherosclerotic plaques and more recently, LPA has been proposed to serve as a ligand for the receptor for advanced glycation end products (RAGE). the actions of local and circulating LPA may be terminated by enzymatic dephosphorylation of the lipid by a family of hexahelical membrane spanning proteins, termed lipid phosphate phosphatases (LPP). of the three LPP enzymes with preference for LPA, LPP3 appears the most likely to play a biologic role in regulating LPA levels, and deficiency of LPP3 results in embryonic lethality in mice due to vascular and neural tube defects. the identification of PPAP2B gene (that encodes LPP3) among 13 loci recently associated with coronary artery disease (CAD) suggests a causal relationship between LPP3 and vascular

disease susceptibility in the clinical settings. Our preliminary work indicates that LPA-induced potentiation of vascular SMCs chemo-taxis occur via RAGE - Erk/MAPK signaling pathways, perhaps through activation of protein kinase C (PKC). Herein we show the molecular events that are initiated by LPP3 in vascular cells under hyperglycemic conditions and their contribution in diabetic restenosis in transgenic mice that lack LPP3 in vascular smooth muscle cells. Our results reveal that LPP3 serves as a molecular switch to control the LPA signaling on RAGE via PI3K and Erk/MAPK pathways during diabetic restenosis. Our results should provide specific insight into LPA signaling systems regulated by LPP3 and may provide novel targets for treatment and prevention of diabetic vascular disorders.

Type 2 Diabetes Mellitus and High Blood Pressure as Risk Factors for Oxidative DNA Damage in Older Adults Raquel Retana-Ugalde1, Héctor Hugo Pérez-Magallanes1, and Víctor Manuel Mendoza-Núñez1 1Universidad Nacional Autónoma de México (Unidad de Investigación en Gerontología, FES Zaragoza), Mexico Background: Oxidative stress (OxS) is a imbalance between the high potential oxidant molecules derived from oxygen known as free radicals (FR) and antioxidant systems, being a transitory phenomenon that occurs by normal metabolism. At the same time, it has been noted that oxidative DNA damage can be a marker of OxS linked to chronic diseases such as high blood pressure (HBP) and type 2 diabetes mellitus (T2DM). Objective: to determine frequency and degree of oxidative DNA damage in older adults with HBP or T2DM. Material and methods: We carried out a cross-sectional study in a sample of 207 older adults: (i) 68 clinically healthy, (ii) 78 with hypertension and (iii) 61 with diabetes mellitus. Oxidative DNA damage was measured by single cell gel electrophoresis assay (comet assay) and levels of 8-OHdG by competitive ELISA (Trevigen). the results were analyzed using ANOVA and Dunnett tests, and odds ratio (OR) with confidence interval of 95% (CI95%) for risk factors. Results: We found that 59% of the diabetic group and 53% of hypertensive patients showed DNA oxidative damage, in contrast to 31% of healthy elderly group (p<0.05). in this sense, HBP was risk factor for DNA damage (OR=2.5 CI95%, 1.3-4.9, p <0.05) likewise T2DM (OR=3.2, CI95%, 1.6-6.7, p <0.05). Also it was observed lower 8-OHdG levels in hypertensive than diabetic and healthy groups (healthy, 154.89, 139.27 diabetic, hypertensive, 118.98nM). Conclusion: Our findings suggest that diabetes mellitus and hypertension are risk factors for oxidative DNA damage oxidative in older adults. This work was supported by grant DGAPA, UNAM, PAPIIT IN306213.

doi: 10.1016/j.freeradbiomed.2013.10.459

doi: 10.1016/j.freeradbiomed.2013.10.460

doi: 10.1016/j.freeradbiomed.2013.10.461

doi: 10.1016/j.freeradbiomed.2013.10.462