This Article Full Text Full Text (PDF) All Versions of this Article: 108/15/1858    most recent 01.CIR.0000089372.64585.3Bv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wong, R. K.M. Articles by Ng, L. L. Search for Related Content PubMed PubMed Citation Articles by Wong, R. K.M. Articles by Ng, L. L. Related Collections Pathophysiology Other diabetes

(Circulation. 2003;108:1858.)
© 2003 American Heart Association, Inc.

Basic Science Reports

Advanced Glycation End Products Stimulate an Enhanced Neutrophil Respiratory Burst Mediated Through the Activation of Cytosolic Phospholipase A₂ and Generation of Arachidonic Acid

Richard K.M. Wong, MA, MRCP; Andrew I. Pettit, BSc, MRCP; Paulene A. Quinn, MPhil; Sonja C. Jennings, HNC; Joan E. Davies, PhD, FRCP; Leong L. Ng, MD, FRCP

From the Division of Medicine and Therapeutics, University of Leicester, Leicester Royal Infirmary, Leicester, UK.

Correspondence to Prof L.L. Ng, Division of Medicine and Therapeutics, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester LE2 7LX, UK. E-mail lln1{at}le.ac.uk

Received December 17, 2002; de novo received April 8, 2003; revision received May 22, 2003; accepted June 6, 2003.

Background— Advanced glycation end products (AGEs) enhance NADPH oxidase, and hence respiratory burst activity, of stimulated neutrophils. They are thus potentially vasculopathic, especially in diabetes, uremia, and aging, in which AGEs classically accumulate. We investigated the underlying mechanisms.

Methods and Results— Neutrophils prelabeled with [³H]arachidonic acid display increased [³H]arachidonate release on exposure to AGE-albumin over exposure to albumin alone (by 151±16%, P<0.01). Arachidonic acid (AA) itself seems to mediate the AGE-augmented neutrophil respiratory burst (ascertained by chemiluminescence). Inhibitors of the cyclooxygenase pathway (indomethacin) and lipoxygenase pathway (MK-886) do not impair this AGE effect, excluding a contribution from AA metabolites. Cytosolic phospholipase A₂ (cPLA₂) controls AA generation. Its inhibition by methyl arachidonyl fluorophosphonate abrogates the AGE-enhanced activated neutrophil respiratory burst, and it is demonstrably stimulated in AGE-exposed neutrophils, as evidenced by isoform gel-shift and an increasingly membrane-translocated state in Western blots of neutrophil subfractions. Inhibition of other PLA₂ isoforms, secretory PLA₂ and calcium-independent PLA₂, by manoalide and haloenol-lactone suicide substrate, respectively, does not affect this effect of AGEs relative to inhibitor-treated controls. The thiol antioxidant NAC reduces activation of cPLA₂ (assessed by isoform gel-shift and membrane translocation), production of AA in AGE-albumin–exposed neutrophils (H³ release reduced to 104±17%, P=0.94 compared with albumin-exposed neutrophils), and the AGE-augmented neutrophil respiratory burst.

Conclusions— AGE augmentation of the activated neutrophil respiratory burst requires AA generation, through which neutrophil NADPH oxidase may be upregulated, enhancing reactive oxygen species output. AA is generated by cPLA₂, which may be stimulated through an AGE-activated redox-sensitive pathway.

Key Words: glycosylation end products, advanced • phospholipases • arachidonic acid • free radicals • NADPH oxidase

This article has been cited by other articles:

				U. R. Michaelis, N. Xia, E. Barbosa-Sicard, J. R. Falck, and I. Fleming Role of Cytochrome P450 2C Epoxygenases in Hypoxia-Induced Cell Migration and Angiogenesis in Retinal Endothelial Cells Invest. Ophthalmol. Vis. Sci., March 1, 2008; 49(3): 1242 - 1247. [Abstract] [Full Text] [PDF]

				M. Karima, A. Kantarci, T. Ohira, H. Hasturk, V. L. Jones, B-H. Nam, A. Malabanan, P. C. Trackman, J. A. Badwey, and T. E. Van Dyke Enhanced superoxide release and elevated protein kinase C activity in neutrophils from diabetic patients: association with periodontitis J. Leukoc. Biol., October 1, 2005; 78(4): 862 - 870. [Abstract] [Full Text] [PDF]