B13.12

Advanced-glycation endproducts implication in theacceleration of diabetes-induced elastocalcinosis

Céline Bouvet, Simon Moreau, Denis deBlois, Pierre Moreau

Université de Montréal, Montréal, Canada

In diabetes, elastocalcinosis is accelerated in distal arteries,and it is correlated with the duration and severity of the disease.We devised a model of elastocalcinosis in association with type2 diabetes in order to study the mechanisms. Males Wistar ratsreceived a high-fat diet during 2 months and then a low doseinjection of streptozotocin (30 mg/kg i.p.) to induce type 2diabetes (D). Elastocalcinosis was induced by 3 weeks oftreatment with warfarin 15 mg/kg/d and vitamin K 15 mg/kg/d(WVK). WVK treatment was started 1 (D1W3) and 4 weeks(D4W3) after the injection of streptozotocin, and in controls(W3). Untreated rats were used as control (Ctrl). Pyridoxamine(100 mg/kg/d) was administered at the beginning of the WVKtreatment (D4W3+pyr). Other rats received ALT711, an AGEsbreaker (10 mg/kg/d), for 4 weeks starting 3 weeks after thebeginning of WVK treatment (D4W7+ALT711). They werecompared to diabetic rats treated with WVK for 7 weeks(D4W7). Three weeks of treatment with WVK alone did notincrease the calcium amount in femoral arteries (W3: 0.36±0.09 vs Ctrl: 0.8±0.1 μg/mg of tissue). Femoral calcificationwas accelerated in the D4W3 group (3.6±1.3 μg/mg, p<0.001),but not in the D1W3 group. AGEs deposition on collagen offemoral artery also increased only in the D4W3 group (2.96±0.79 vs W3: 0.76±0.26 AU/mg collagen, p<0.05). Nosignificant change of the aortic calcium amount was observedin all groups. Femoral calcification was significantly preventedby pyridoxamine (D4W3+pyr: 0.6±0.1 vs D4W3: 3.6±1.3 μg/mg, p<0.05) and with ALT711 (D4W7+ALT711: 3.2±0.7 vsD4W7: 10.5±3.4 μg/mg, p<0.001). We have established amodel of accelerated elastocalcinosis in diabetes linked to itsduration, severity and localized in distal arteries. Thiscalcification was prevented with pyridoxamine and its progres-sion was limited by ALT 711, suggesting that, in diabetes,accelerated elastocalcinosis is linked to AGEs formation.

doi:10.1016/j.vph.2006.08.266

B13.13

Role of sphingosine kinase-1 in high-glucose mediatedendothelial inflammation

Pu Xia

Signal Transduction Laboratory, Hanson Institute, Adelaide,Australia

Vascular endothelial cells are key targets for hyperglycemicdamage that facilitates vascular inflammation and the vasculo-pathy associated with diabetes mellitus. However, the mechan-

isms underlying this damage remain undefined. We nowdemonstrate that hyperglycemia induces activation of sphingo-sine kinase (SphK) which represents a novel signaling pathwaythat mediates endothelial inflammation under ambient highglucose conditions. SphK activity was significantly increased inthe aorta and heart of STZ-induced diabetic rats. Interestingly,this increase in SphK activity was prevented by insulintreatment that achieved euglycemia in the diabetic animals.Hyperglycemia-induced increase in SphK activity was alsoevident in endothelial cells that were chronically exposed tohigh glucose (22 mmol/L). Studies using a small interferingRNA (siRNA) strategy demonstrated that endogenous SphK1,but not SphK2, is the major isoenzyme that was activated byhigh glucose. In addition, an increase in SphK1 phosphorylationwas detected in a PKC- and ERK1/2-dependent manner, whichaccounts for the high glucose-induced increases in SphKactivity. Importantly, inhibition of SphK1 by either a chemicalinhibitor (N′N′-dimethylsphingosine) or expression of adominant-negative mutant of SphK1 (SphKG82D), or SphK1-specific siRNA, strongly protected endothelial cells againsthigh glucose-induced inflammatory phenotypes, as character-ized by an attenuation in the expression of pro-inflammatoryadhesion molecules, adhesion of leukocytes to endothelial cellsand NF-kB activation. Thus, interventions that target the SphKsignaling pathway may have the potential to prevent vascularlesions under hyperglycemic conditions.

doi:10.1016/j.vph.2006.08.267

B13.14

The effect of maternal hypercholesterolemia on vasculardifferentiation and fetal plasma cholesterol levels

Fanneke E. Alkemade1, Marco C. DeRuiter1,Ko Willems van Dijk2, Conny J. VanMunsteren1,Louis M. Havekes3, Adriana C. Gittenberger-de Groot1

1Dept. Anatomy and Embryology, Leiden University MedicalCenter, Leiden, The Netherlands2Dept. Human Genetics, Leiden University Medical Center,Leiden, The Netherlands3TNO-Quality of life, Gaubius Laboratory, Leiden,The Netherlands

Intrauterine exposure of the human fetus to high levels ofcholesterol appears to lead to increased formation of fattystreaks in the fetal aorta and promotes development ofatherosclerosis in adult life. However, little is known on thecontribution of genetic background of the fetus on intrinsic lipidmetabolism and vascular remodeling in combination withmaternal normo- or hypercholesterolemia (M-NC, M-HCrespectively). We hypothesize that M-HC results in changesin fetal plasma lipid levels leading to altered vascularremodeling in the embryo and increased susceptibility tovascular disease in adult offspring. C57Bl/6J wild type, LDL

e9514th IVBM Abstracts