PP03Oxidative stress cause liver damage in adultβ-thalassemia major at Dubai thalassemia center

A.L. Altaie a, F.A.A Lkhaja b

a Zayed University, Abu Dhabi, UAEb Dubai Thalassemia Center, Dubai, UAEE-mail address: Ala.altaie@zu.ac.ae (A.L. Altaie)

β thalassemia is a genetic disorder that affects the synthesis ofnormal hemoglobin (Hb) rendering the patient blood transfusiondependent for lifelong. This Regular blood transfusion generatesReactive oxygen species (ROS) and consequently tissue damage.We studied the oxidative status, antioxidant and serumhemoxygenase-1 (HO-1) an antioxidant protein in 17 β thalassemiapatients with liver damage following in Dubai Thalassemia Centerand 18 normal controls. Our results showed significant increase insuperoxide dismutase (SOD) activity and decrease in the catalase(CAT) activity in patients compared to controls. Elevated serumferritin showed positive correlation with SOD activity. Similarlyserum glutamic pyruvic transaminase (sGPT) showed positivecorrelation with serum ferritin and SOD activity and negativecorrelation with CAT. The serum HO-1 showed no significantdifference between the two groups. In conclusion we clearlydemonstrated that iron overload due to regular blood transfusions,leads to high levels of oxidative stress and decrease the antioxidantactivity in β thalassemia patients. This generated oxidative stress isthe cause of liver damage in those chronically transfused patients.

http://dx.doi.org/10.1016/j.freeradbiomed.2013.08.012

PP04Characterization of new alkanal-phosphatidylethanol-amine adducts

Andrea Annibal a,b,c,d, Ralf Hoffmann a,b,d, Jürgen Schiller b,c,d,Maria Fedorova a,b

a Institute of Bioanalytical Chemistry, Faculty of Chemistry and Miner-alogy, Universität Leipzig,Leipzig, Germanyb Center for Biotechnology and Biomedicine, Universität Leipzig,Leipzig, Germanyc Institute for Medical Physics and Biophysics, Faculty of Medicine,Universität Leipzig, Germanyd LIFE-Leipzig Research Center for Civilization Diseases, UniversitätLeipzig, Germany

Aldehydes generated as a result of lipid peroxidation representpromising biomarkers of oxidative stress that plays a major role inmany human diseases and inflammation. Reactive oxygen species(ROS) can oxidize fatty acyl residues of phospholipids yielding aheterogeneous class of lipids peroxidation products (LPPs) includingthe cleavage of free unsaturated and saturated aldehydes. Carbonylgroups present in LPPs are highly reactive to nucleophilic groups inother biomolecules, such as the side chains of lysine, cysteine andhistidine residues in proteins or amino groups in phosphatidyletha-nolamines (PE). Whereas the reactivity of unsaturated aldehydes hasbeen well investigated, only few data are available for saturatedaldehydes. Here we report new alkanal-PE adducts identified bymass spectrometry (MS) using consecutive fragmentations (MSn) aswell as their formation quantified by multiple reaction monitoring(MRM) obtained by incubating dipalmitoylphosphatidylethanola-mine (DPPE, 0.1 mmol/L) with hexanal (0.4 mol/L) in aqueous

solutions (1 h, 371C). Lipids were extracted and analyzed byESI-LTQ-Orbitrap-MS (shotgun lipidomics). Surprisingly, eightdifferent products were identified including two previouslyreported (Schiff-base and amide) and six new compounds. Thenew PE-hexanal adducts contained dimeric and trimeric hexanalconjugates formed by consecutive β-aldol condensation.

In order to study the biological relevance of hexanal-adducts,trimeric hexanal-PE was purified and added to multilamellarvesicles of dipalmitoleoylphosphatidylethanolamine (DiPoPE,5.5 g/L). Differential scanning calorimetry (DSC) enabled to moni-tor the membrane curvature change induced by the incorporationof trimeric hexanal-PE into lipid vesicles. It was shown thattrimeric hexanal modification appears to be sufficient to increasethe negative curvature of multilamellar vesicles in vitro. Thisindicates that formation of the hexanal-PE adduct could influencethe structure and the status of biological membranes leading to achange in macroscopic structure, stability and function.

http://dx.doi.org/10.1016/j.freeradbiomed.2013.08.013

PP05Specific kidney cortico-medullary distribution of NADPHoxidase-gp91phox contributes to age-related hypertensionand salt-sensitivity in Fischer Brown Norway (FBN) rats

M. Asghar, I. Pokkunuri, G. Chugh, M. Lokhandwala

Department of Pharmacological and Pharmaceutical Sciences Heartand Kidney Institute, University of Houston, Houston, TX, USAE-mail address: masghar@uh.edu (M. Asghar)

We recently reported that oxidative stress is causal to hypertensionand impaired kidney angiotensin AT1 receptor (AT1R) and dopamineD1 receptor (D1R) functions in aging FBNs. These renal receptors bycounter-regulating each other’s functions maintain sodium home-ostasis and normal blood pressure (BP). Here, we tested whether ornot these rats develop salt-sensitivity and examined cortico-medullarydistribution of these receptors and oxidant producing enzyme NADPHoxidase-gp91phox in response to 4-week normal-salt (NS, 0.4% NaCl)and high-salt (HS, 8% NaCl) feeding in adult (3-month) and old (21-month) FBNs. BP in conscious animals was measured by radio-telemetry. Distribution of D1R, AT1R and gp91phox were determinedby RT-PCR and western blotting. We found that NS-fed old rats hadhigher BP than NS-fed adult rats, which further increased with HSfeeding in old rats. BP did not change with HS feeding in adult rats.The levels of D1R mRNA in cortex or in medulla were not differentbetween NS-fed adult and old rats, but decreased in both cortex andmedulla only in HS-fed old rats. Contrary to this, AT1R mRNA levelswere higher only in cortex of old rats fed either NS or HS. Moreover,despite similar gp91phox mRNA levels in cortex and medulla betweenadult and old rats fed either NS or HS, gp91phox protein levels werehigher in the cortex of old rats irrespective of salt treatment andincreased only in the medulla of old rats with HS in these rats. Ourresults suggest that age-related hypertension and salt-sensitivity isassociated with specific cortico-medullary distribution of gp91phox,which, by a redox mechanism, may cause transcriptional and func-tional dysregulation of AT1R and D1R contributing to hypertension inthe old animals.

http://dx.doi.org/10.1016/j.freeradbiomed.2013.08.014

Abstract / Free Radical Biology and Medicine 65 (2013) S23–S56S24