Abstract 505: Young Adults With Juvenile Dermatomyositis Have Endothelial Dysfunction: Studies of Brachial Artery Reactivity and Oxidized Lipids

Abstract

Objective: Older patients with Juvenile Dermatomyositis (JDM) have increased carotid wall thickness and decreased nailfold capillary end row loops (ERL). This study tested young adults with JDM and decreased ERL for brachial artery reactivity (BAR) and HDL antioxidant function. Methods: 20 adults, 14 F, mean age 21.8± 4.2 yrs; mean age at JDM onset 7.6 ± 3.7 years, mean duration of untreated disease (DUD) at diagnosis 5.4 ± 4.8 months, and mean total duration of disease 14.2 ±3.9 years. JDM adults had a mean Total Disease Activity Score (DAS) 1.9 ± 2.5 and were medication free. They were matched by age, race, sex and BMI with 20 healthy controls (mean age 23.8 ± 4.2 years). All subjects were tested for: BAR, ERL number, height and weight. The antioxidant function of HDL was evaluated by the change in fluorescence intensity caused by oxidation of dichlorfluorescein-diacetate by oxidized LDL ±HDL was measured (mean HDL function in healthy controls ranges from 0.44 - 0.66).For BAR, individuals were fasting and rested supine for 10 minutes before ultrasound imaging. Brachial artery diameter was measured at rest and one minute after 4.5 minutes of supra-systolic forearm occlusion. BAR was expressed as the percent diameter change from baseline in response to increased sheer stress [(post-deflation - baseline diameter)/baseline diameter] x100. Results: The # of ERL were significantly lower in the JDM group, 6.35 ± 1.29 vs the controls, 7.4±0.58, p=0.003. The TNF-α -308A allele in the JDM group was 40% vs. 15% in controls. JDM were shorter than their controls, for JDM women, 159.7 ±8.8cm vs. 165.6 ±5.4cm, p=0.048, and for JDM men, 172.7±3.6cm compared to controls, 181.5 ±4.6cm, p=0.0046, perhaps a consequence of steroid administration. BAR in JDM was 3.35±3.06%, and 5.22±3.07% in normal controls (p=0.068). After adjusting for height, age, sex, and BA diameter, the BAR in JDM adults was significantly lower than controls by 2.31% (p=0.04). There were no associations of BAR with ERL, DUD, or DAS or oxidized lipids. Conclusion: BAR is decreased in young adults off medication for JDM, indicating endothelial cell dysfunction. Larger studies in young adults with JDM are needed to validate this finding