35° Congresso Nazionale della Società Italiana di Farmacologia

ABSTRACT

Title

Pharmacological modulation of AMP-activated protein kinase as a novel target for the treatment of inflammatory bowel diseases

Authors

L. Antonioli¹, M. Fornai¹, R. Colucci¹, O. Awwad¹, M. Tuccori¹,C. Maramai¹, G. Natale², F. Fulceri², I. Rugani³, E. Duranti³, A. Virdis³, C. Blandizzi¹

¹Interdepartmental Centre for Research in Clinical Pharmacology and Experimental Therapeutics, ²Department of Human Morphology and Applied Biology, and ³Department of Internal Medicine, University of Pisa, Pisa, Italy

Abstract

Introduction. Acadesine, an activator of AMP-activated protein kinase (AMPK), has been shown to act in a site- and event-specific manner against inflammation, through local increments of endogenous adenosine levels. However, the effects of acadesine on intestinal inflammation have been scarcely investigated. This study was aimed to evaluate the effects of acadesine in an experimental model of colitis and to characterize the underlying anti-inflammatory mechanisms. Methods. The effects of acadesine and dexamethasone (used as a standard comparator)were tested in male Sprague-Dawley rats (n=6 for each group) with colitis induced by intrarectal administration of 2,4-dinitrobenzenesulfonic acid (DNBS, 15 mg in 0.25 ml of 50% ethanol), to assess systemic [body and spleen weight] and tissue inflammatory parameters [macroscopic and microscopic damage, tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), in situ superoxide anion production (dihydroethidium fluorescence) and malondialdehyde (MDA) levels]. Animals received acadesine (1, 3, 10 or 30 mg/kg/day), dexamethasone (0.1 mg/kg/day) or vehicle intraperitoneally for 6 days, starting 1 day before DNBS administration. Results. The induction of colitis was associated with a decreased body weight (-10±5 g vs vehicle; P<0.05) and increased spleen weight (+22±3% vs vehicle; P<0.05). Microscopic damage score, tissue TNF-α and oxidative stress were markedly enhanced, while tissue IL-10 levels were significantly reduced. Treatment with acadesine, but not dexamethasone, improved body weight. Both drugs counteracted the increase in spleen weight and ameliorated the histological damage (DNBS: 4.8±0.9; acadesine 10 mg/kg/day: 3.1±0.7; dexamethasone: 2±0.4; P<0.05 vs DNBS; ANOVA). A reduction of TNF-α and increase in IL-10 tissue levels were also recorded in rats treated with test drugs. Moreover, acadesine or dexamethasoneameliorated colonic oxidative damage. Data regarding the effects of acadesine and dexamethasoneon inflammatory parameters are summarized in table (*P<0.05 vs vehicle; ^aP<0.05 vs DNBS).Conclusions.The AMPK activator acadesine exerts beneficial effectson bowel inflammation, acting through a rearrangement of pro-inflammatory/anti-inflammatory cytokine balance and a reduction of oxidative stress. These findings suggest that the pharmacological modulation of AMPK function could represent a promising strategy to develop novel classes of drugs effective against intestinal inflammation.

MACROSCOPIC DAMAGE

TNF-α

(pg/mg tissue)

IL-10

(pg/mg tissue )

MDA

(μmol/mg tissue)

SUPEROXIDE PRODUCTION
(% area stained)

Vehicle

1.2±0.3

5.1±1

9.4±1.5

162.6±30

12±3.2

DNBS

8.2±1.5*

9.6±1.2*

4.4±0.8*

588±45.3*

53±13.6*

DNBS+Acadesine
1 mg/kg/day

7.4±0.8*

10.9±2.3*

8.3±1.4^a

513.7±41*

47.2±7.3*

DNBS+ Acadesine
3 mg/kg/day

4.6±0.7*^,a

6±1.5*^,a

8.6±1.3^a

528.7±51.1*

25±6.5*^,a

DNBS+ Acadesine
10 mg/kg/day

2.9±0.4*^,a

7.3±0.4*^,a

9.7±1.2^a

328.6±45*^,a

15.2±7.1^a

DNBS+ Acadesine
30 mg/kg/day

3.8±0.9*^,a

6.7±1.4*^,a

9.3±0.8^a

368.5±22.3*^,a

13.8±5.4^a

DNBS+Dexamethasone

0.1mg/kg/day

2.7±0.4*^,a

4.5±1.3^a

8±0.7^a

240.7±31.4*^,a

12.6±4.7^a