Increased O-linked β-N-acetylglucosamine levels on proteins ... : Critical Care Medicine (original) (raw)

Laboratory Investigations

Increased O-linked β-N-acetylglucosamine levels on proteins improves survival, reduces inflammation and organ damage 24 hours after trauma-hemorrhage in rats

Nöt, Laszlo G. MD; Brocks, Charlye A. BA; Vámhidy, Laszlo MD, PhD; Marchase, Richard B. PhD; Chatham, John C. DPhil

From the Department of Cell Biology (LGN, RBM, JCC), Division of Cardiovascular Disease (CAB, JCC), Department of Medicine, Department of Physiology and Biophysics (JCC), Center for Cardiovascular Biology, Center for Free Radical Biology, Center for Aging, University of Alabama at Birmingham, Birmingham, AL; and the Department of Traumatology and Hand Surgery (LGN, LV), Institute of Musculoskeletal Surgery, University of Pécs, Pécs, Hungary.

This study was supported, in part, by grant HL076165 (RBM) and HL079364 (JCC) from the National Institutes of Health.

Drs. Marchase and Chatham have pending patents. All other authors have no potential conflicts of interest to disclose.

For information regarding this article, E-mail: [email protected]

Abstract

Objective:

To evaluate the effects of O-linked β-N-acetylglucosamine (O-GlcNAc) levels on survival, inflammation, and organ damage 24 hrs after trauma-hemorrhage. We have previously shown that increasing protein O-GlcNAc levels by different mechanisms reduced inflammatory responses and improved organ function 2 hrs after trauma-hemorrhage.

Design:

Prospective, randomized, controlled study.

Setting:

Animal research laboratory.

Subjects:

Male, adult Sprague-Dawley rats.

Interventions:

Overnight fasted animals were subjected to either sham surgery or trauma-hemorrhage and during the resuscitation phase received glucosamine (270 mg/kg) to increase O-GlcNAc synthesis or O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino N-phenyl carbamate (PUGNAc, 7 mg/kg) to inhibit O-GlcNAc removal, or mannitol as control.

Measurements and Main Results:

Survival was followed up for 24 hrs. Surviving rats were euthanized and inflammatory responses, and end organ injuries were assessed. Both glucosamine and PUGNAc increased 24-hr survival compared with controls (control: 53%, GN: 85%, PUGNAc: 86%, log-rank test, p < .05). PUGNAc attenuated the trauma-hemorrhage-induced increase in serum interleukin-6 (sham surgery: 8 ± 6, control: 181 ± 36, PUGNAc: 42 ± 22 pg/mL, p < .05), alanine transaminase (sham surgery: 95 ± 14, control: 297 ± 56, PUGNAc: 126 ± 21 IU, p < .05), aspartate transaminase (sham surgery: 536 ± 110, control: 1661 ± 215, PUGNAc: 897 ± 155 IU, p < .05), and lactate dehydrogenase (sham surgery: 160 ± 18, control: 1499 ± 311, PUGNAc: 357 ± 99 IU, p < .05); however, glucosamine had no effect on these serum parameters. Furthermore, PUGNAc but not glucosamine maintained O-GlcNAc levels in liver and lung and significantly attenuated the NF-κB DNA activation in the liver. In the liver and heart, increased inducible nitric oxide synthase expression was also attenuated in the PUGNAc-treated group.

Conclusions:

These results demonstrate that increasing O-GlcNAc with either glucosamine or PUGNAc improved 24-hr survival after trauma-hemorrhage. However, only PUGNAc treatment attenuated significantly the subsequent tissue injury and inflammatory responses, suggesting that inhibition of O-GlcNAc removal may represent a new therapeutic approach for the treatment of hypovolemic shock.