Pharmacological Research 58 (2008) 356–363 Contents lists available at ScienceDirect Pharmacological Research journal homepage: www.elsevier.com/locate/yphrs Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat Pitchai Balakumar ∗ , Ramica Sharma, Manjeet Singh Cardiovascular Pharmacology Division, ISF College of Pharmacy, Moga 142001, Punjab, India article info Article history: Received 24 August 2008 Received in revised form 24 September 2008 Accepted 25 September 2008 Keywords: Nicotine Uric acid Oxidative stress Nitric oxide Vascular endothelial dysfunction Benfotiamine abstract The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nico- tine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2 mg kg -1 day -1 , i.p., 4 weeks) and uric acid (150 mg kg -1 day -1 , i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and aortic concentration of nitrite/nitrate. Further, the integrity of vascular endothelium was assessed using the scanning electron microscopy (SEM) of thoracic aorta. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion gener- ation. The administration of nicotine and uric acid produced VED by impairing the integrity of vascular endothelium and subsequently decreasing serum and aortic concentration of nitrite/nitrate and attenu- ating acetylcholine-induced endothelium dependent relaxation. Further, nicotine and uric acid produced oxidative stress, which was assessed in terms of increase in serum TBARS and aortic superoxide generation. However, treatment with benfotiamine (70 mg kg -1 day -1 , p.o.) or atorvastatin (30 mg kg -1 day -1 p.o., a standard agent) markedly prevented nicotine and uric acid-induced VED and oxidative stress by improv- ing the integrity of vascular endothelium, increasing the concentration of serum and aortic nitrite/nitrate, enhancing the acetylcholine-induced endothelium dependent relaxation and decreasing serum TBARS and aortic superoxide anion generation. Thus, it may be concluded that benfotiamine reduces the oxida- tive stress and consequently improves the integrity of vascular endothelium and enhances the generation of nitric oxide to prevent nicotine and uric acid-induced experimental VED. © 2008 Elsevier Ltd. All rights reserved. 1. Introduction Endothelium is an innermost layer of blood vessels. A healthy endothelium possesses antiatherogenic, antiplatelet and antipro- liferative properties to regulate the vascular tone and maintain the free flow of blood in vessels [1,2]. Nitric oxide (NO), a potent vasodilatory substance, is generated from l-arginine by endothe- lial nitric oxide synthase (eNOS) in the presence of cofactors such as Ca ++ -calmodulin, reduced nicotinamide adenine dinucleotide phosphate (NADPH), flavin adenine dinucleotide (FAD) and tetrahy- drobiopterin (BH4) in endothelial cells [3,4]. Vascular endothelial dysfunction (VED) is characterized by suppression of endothe- lium dependent vasorelaxation caused by reduced generation and bioavailability of nitric oxide (NO) due to reduced activity of eNOS and increased oxidative stress in the vessel wall, which in turn impair the regulation of vascular homeostasis [5–7]. VED has been associated in the pathogenesis of atherosclerosis [8], ∗ Corresponding author. Tel.: +91 9815557265; fax: +91 1636236564. E-mail address: pbala2006@gmail.com (P. Balakumar). hypertension [9], diabetes mellitus [2,10], coronary artery diseases [11] and stroke [12]. Various risk factors including hyperuricemia and cigarette smoking are implicated in the vascular pathogen- esis [13,14]. Hyperuricemia, a condition of increased serum uric acid, has been implicated in pathogenesis of VED [14,15]. Uric acid is the major product formed from purine metabolism. Gout, is an inflammatory disorder characterized by increased uric acid level and has been reported to produce vascular pathogenesis [14–16]. Hyperuricemia has been noted to decrease the vascular generation of NO through inactivation of eNOS [16]. Further, hyper- uricemia has been shown to produce reactive oxygen species (ROS) excessively through activation of NADPH oxidase and xanthine oxi- dase [17–20]. The C-reactive protein (CRP) level was noted to be increased in hyperuricemia-induced VED [21]. Hyperuricemia has been regarded as an independent risk factor for various cardio- vascular disorders such as atherosclerosis [22], hypertension [23] and heart failure [24]. Nicotine exposure via cigarette smoking has been implicated in pathogenesis of cardiovascular disorders like atherosclerosis [25] and hypertension [26]. Moreover, nicotine has been noted to produce VED by downregulating the expression of eNOS, increasing the generation of ROS and upregulating asymmet- 1043-6618/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.phrs.2008.09.012