European Journal of Pharmacology (v.662, #1-3)

Effects of bezafibrate in nonalcoholic steatohepatitis model mice with monosodium glutamate-induced metabolic syndrome by Yoshiyuki Sasaki; Tsutomu Shimada; Seiichi Iizuka; Wataru Suzuki; Hiroko Makihara; Ryutaro Teraoka; Koichi Tsuneyama; Ryoji Hokao; Masaki Aburada (1-8).
Recently, we reported that monosodium glutamate-treated mice (MSG mice) developed severe hyperlipidemia and diabetes mellitus and several complications of obesity. MSG mice acquired fatty livers and subsequently underwent changes that are characteristic of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH). In the present study, the effects of bezafibrate on obesity, diabetes mellitus, and NAFLD/NASH were examined in MSG mice. A single dose of MSG (4 mg/g) was administered subcutaneously to neonatal male mice within 24 h of birth. Bezafibrate was mixed into the normal feed for 8 weeks. The weight and body mass index of MSG mice increased significantly despite the unchanged intake of food. Triglyceride and total cholesterol levels in blood, visceral adipose tissue, and interscapular adipose tissue rose significantly. In the livers of MSG mice, moderate centrilobular microvesicular steatosis, ballooning degeneration with Mallory bodies, and scattered infiltration of neutrophils and lymphocytes were observed. Centrilobular hepatocytes were 4-hydroxynonenal-positive in MSG mice. Bezafibrate ameliorated the severity of diabetes mellitus, hyperinsulinemia, and hyperlipidemia. Adiponectin and leptin concentrations in blood improved, and the accumulation of visceral fat was inhibited. The expression of acyl-CoA oxidase, a beta-oxidation gene, and carnitine palmitoyl transferase, which regulates lipid metabolism, increased markedly on administration of bezafibrate. The liver pathology in MSG mice also improved with bezafibrate; specifically, macro- and microvesicles in hepatocytes nearly disappeared, and NAFLD activity score improved. It is concluded that bezafibrate inhibits the accumulation of visceral fat, following amelioration of hyperlipidemia, in MSG-induced obese mice, due to improvements in diabetes mellitus, fatty liver, and NAFLD.
Keywords: Obesity; Diabetes mellitus; Metabolic syndrome; Nonalcoholic fatty liver disease;

Regulation mechanism of ABCA1 expression by statins in hepatocytes by Masaki Kobayashi; Keisuke Gouda; Ikumi Chisaki; Manami Ochiai; Shirou Itagaki; Ken Iseki (9-14).
ATP-binding cassette transporter A1 (ABCA1) is predicted to be involved in the control of apolipoprotein AI-mediated cholesterol efflux: biosynthesis of high-density lipoprotein (HDL). However, the effects of HMG-CoA reductase inhibitors (statins) on ABCA1 in the liver and the precise mechanisms of their actions have been obscure. The aims of this study were to determine whether statins (atorvastatin (Ato) and pitavastatin (Pit)) affect hepatic ABCA1 expression and to clarify the mechanisms of their actions using HepG2 cells and the rat liver. We examined alterations in mRNA and protein levels of ABCA1 and peroxisome proliferator-activated receptors (PPARs) by quantitative real-time polymerase chain reaction (PCR) and Western blot analysis, respectively. In vitro and in vivo studies suggested that Pit increases ABCA1 mRNA level, but not Ato. Pit greatly increased Abca1 mRNA level and also increased the amount of plasma HDL and the mRNA level of PPARα. Clofibrate (PPARα agonist) increased ABCA1 expression in HepG2 cells and rat primary hepatocytes more than did PPAR β/δ and γ agonists. Pit-induced ABCA1 expression alteration was blocked by GW6471 (PPARα antagonist) and by PPARα knockdown. In this study, we demonstrated that Pit affect ABCA1 expression via PPARα in hepatocytes. The strategy to target a PPARα agonist in the liver can lead to increases in ABCA1 expression and HDL level.
Keywords: Statin; PPARs; ABCA1; Regulation; Hepatocyte;

Methyllycaconitine (MLA) is a norditerpenoid alkaloid found in high abundance in toxic Delphinium (larkspur) species. It is a potent and selective antagonist of α7-nicotinic acetylcholine receptors, but has not been well investigated for activity aside from receptor antagonism. The aim of this study was to investigate the effects of MLA alone and in combination with acetylcholine, epibatidine, nicotine, and neostigmine for actions other than receptor antagonism in TE-671 cells expressing (α1)2β1γδ nicotinic acetylcholine receptors. Ligand activity was assessed through measurements of membrane potential changes in TE-671 cells using a fluorescent membrane potential-sensitive dye and normalized to the maximum response to epibatidine (10 μM). MLA was ineffective in changing cell membrane potential in the absence of other receptor agonists. However at nanomolar concentrations, it acted as a co-agonist to potentiate TE-671 cell responses to acetylcholine, epibatidine, nicotine, and neostigmine. These results suggest that the poisoning of cattle by norditerpenoid alkaloids found in larkspur may be more complex than previously determined.
Keywords: Methyllycaconitine; Delphinium; Fetal muscle-type nicotinic acetylcholine receptors; Membrane potential; Neostigmine;

PASS assisted prediction and pharmacological evaluation of novel nicotinic analogs for nootropic activity in mice by Navneet Khurana; Mohan Pal Singh Ishar; Asmita Gajbhiye; Rajesh Kumar Goel (22-30).
The aim of present study is to predict the probable nootropic activity of novel nicotine analogues with the help of computer program, PASS (prediction of activity spectra for substances) and evaluate the same. Two compounds from differently substituted pyridines were selected for synthesis and evaluation of nootropic activity based on their high probable activity (Pa) value predicted by PASS computer program. Evaluation of nootropic activity of compounds after acute and chronic treatment was done with transfer latency (TL) and step down latency (SDL) methods which showed significant nootropic activity. The effect on scopolamine induced amnesia was also observed along with their acetylcholine esterase inhibitory activity which also showed positive results which strengthened their efficacy as nootropic agents through involvement of cholinergic system. This nootropic effect was similar to the effect of nicotine and donepezil used as standard drugs. Muscle coordination and locomotor activity along with their addiction liability, safety and tolerability studies were also evaluated. These studies showed that these compounds are well tolerable and safe over a wide range of doses tested along with the absence of withdrawal effect which is present in nicotine due to its addiction liability. The study showed that these compounds are true nicotine analogs with desirable efficacy and safety profile for their use as effective nootropic agents.
Keywords: Nicotine acetylcholine receptor; Nootropic agent; Nicotine analog; Acetylcholine esterase activity;

Class I/B antiarrhythmic property of ranolazine, a novel antianginal agent, in dog and human cardiac preparations by Tamás Szél; István Koncz; Norbert Jost; István Baczkó; Zoltán Husti; László Virág; Alexandra Bussek; Erich Wettwer; Ursula Ravens; Julius Gy Papp; András Varró (31-39).
The aim of this study was to investigate the cellular electrophysiological effects of ranolazine on action potential characteristics. The experiments were carried out in dog and human cardiac preparations using the conventional microelectrode technique. In dog Purkinje fibres ranolazine produced a concentration- and frequency-dependent depression of the maximum rate of depolarization (Vmax) while action potential duration (APD) was shortened. In dog and human right ventricular papillary muscle ranolazine exerted no significant effect on APD, while it produced, like mexiletine, use-dependent depression of Vmax with relatively fast onset and offset kinetics. In dog midmyocardial preparations the drug did not exert statistically significant effect on repolarization at 10 μM, although a tendency toward prolongation was observed at 20 μM. A moderate lengthening of APD90 by ranolazine was noticed in canine atrial preparations obtained from dogs in sinus rhythm and in tachypacing induced remodelled preparations. Use-dependent depression of Vmax was more pronounced in atria from dogs in sinus rhythm than those in remodelled atria or in the ventricle. These findings indicate that ranolazine, in addition to its known late sodium current blocking effect, also depresses peak INa with class I/B antiarrhythmic characteristics. Although peak INa inhibition by ranolazine is stronger in the atria, it is also substantial (at fast stimulation frequencies) in ventricular preparations. Ranolazine also decreased the dispersion of ventricular repolarization (the difference in APD90 values between Purkinje fibres and papillary muscles), which can contribute to the antiarrhythmic property of the drug.
Keywords: Ranolazine; Action potential; Sodium channel; Electrophysiology; Dog and human cardiac preparations; M-cell;

Effect of dinitrosyl iron complexes with glutathione on hemorrhagic shock followed by saline treatment by Marina I. Remizova; Nikolai I. Kochetygov; Konstantin A. Gerbout; Vladimir L. Lakomkin; Alexander A. Timoshin; Evgenia N. Burgova; Anatoly F. Vanin (40-46).
It has been found that dinitrosyl iron complexes with glutathione (DNIC-GS) injected into the blood flow of rats at a dose of 0.05 μmoles/kg prior to hemorrhage significantly improve cardiac function under conditions of hemorrhagic shock manifested in increased stroke volume, left ventricular work and cardiac output to a level exceeding control values 1.5-fold. Enhanced myocardial contractile activity leads to a situation where mean arterial pressure does not decrease further despite the significant decrease of total peripheral resistance. The decrease of total peripheral vascular resistance of the vascular system under vasodilating effects of DNIC-GS used as nitric oxide donors improves microcirculation in experimental rats judging from increased rates of blood flow and low degree of erythrocyte aggregation. Pretreatment of rats with the complexes significantly increases survival (by 21%) under conditions of hemorrhagic shock. It is suggested that beneficial effects of DNIC-GS on systemic circulation parameters under conditions of hemorrhagic shock are determined by their antioxidant activity and the ability to induce S-nitrosylation of proteins.
Keywords: Nitric oxide; Dinitrosyl iron complex; Hemorrhagic shock;

TNBS-induced colitis has characteristics resembling human Crohn's disease including transmural inflammation, ulceration, and fibrosis. Current treatments target acute symptoms but do not necessarily prevent fibrotic complications of the disease. The aim of this study was to determine the effect of pentoxifylline and its primary metabolite (M-1) on fibrosis in the TNBS-induced colitis model. Myeloperoxidase activity and interleukin-18 are indicators of inflammation and were elevated in the TNBS model. The morphology damage score assesses colon damage and was also elevated in the TNBS model. Collagen as the indicator of fibrosis was quantified and visualized by the Sirius Red/Fast Green staining technique and collagen type I was assessed by Western analysis. Collagen was elevated in the TNBS-induced model. Pentoxifylline and M-1 treatment significantly attenuated colon damage and inflammation in TNBS-colitis (P < 0.05). M-1 treatment significantly reduced the TNBS-induced increase in colon weight, colon thickness and total collagen content (P < 0.05). Results suggest that pentoxifylline and M-1 inhibit intestinal fibrosis in this experimental model and may prove beneficial in the treatment of intestinal fibrosis associated with human Crohn's disease with the added benefit of inhibiting inflammation and ulceration. This is the first study to examine the effects of racemic M-1 in vivo and one of the few studies to examine the effect of drugs on both inflammation and fibrosis in an experimental model of colitis.
Keywords: Fibrosis; Pentoxifylline; Trinitrobenzenesulfonic acid; Interleukin-18;

The activation of C-fibers in the airways induces coughing, mucus production and bronchoconstriction, which are also symptoms of airway diseases. In this study, we evaluated the role of the C-fibers and the TRPV1 (transient receptor potential vanilloid 1) receptor in an experimental mouse model of allergic airway inflammation. To study the role of C-fibers, we either degenerated the C-fibers persistently (capsaicin administration in neonate mice) or transiently (capsaicin administration in adult mice). No alteration was observed in eosinophil recruitment to the bronchoalveolar lavage fluid in animals treated with capsaicin in the neonatal period. However, in adult animals, capsaicin treatment after the first ovalbumin challenge (in the establishment of the inflammatory process) decreased the eosinophil numbers. This effect was more pronounced in adult animals treated with capsaicin before beginning the ovalbumin immunization (in the development of the inflammatory process). In addition, interleukin (IL)-5 and chemokine ligand 11 (CCL11) levels in the bronchoalveolar lavage fluid, as well as P-selectin expression and p65 nuclear factor κB (NF-κB) activation in the lung were also decreased. No alterations were observed in the IL-10 and IL-13 levels. Next we determined the effect of TRPV1 receptor blockade on allergic airway inflammation. SB366791 administrated in mice by intraperitoneal (500 μg/kg) or intranasal (0.1, 1 or 10 nmol/site) route failed to decrease eosinophil recruitment to the bronchoalveolar lavage fluid or alter any other metrics cited above. Thus, the present results confirm and extend previous data supporting the involvement of C-fibers, but not the TRPV1 receptor, in allergic airway inflammation.
Keywords: C-fiber; TRPV1; Capsaicin; Eosinophil; Allergic airways inflammation;

Embelin reduces cutaneous TNF-α level and ameliorates skin edema in acute and chronic model of skin inflammation in mice by G. Kalyan Kumar; R. Dhamotharan; Nagaraj M. Kulkarni; Mahamad Yunnus A. Mahat; J. Gunasekaran; Mohammad Ashfaque (63-69).
Tumor necrosis factor-α (TNF-α) is known to play a crucial role in the pathogenesis of psoriasis. The present study was designed to investigate the effects of embelin on lipopolysachharide induced TNF-α production in mice and in human keratinocytes in vitro and also to study the effect of embelin on acute and chronic skin inflammation in mice. Production of pro-inflammatory cytokines (TNF-α and IL-1β), activation of myeloperoxidase and histological assessment were examined in acute and chronic skin inflammation using 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced mouse ear edema. Embelin inhibited topical edema in the mouse ear, leading to substantial reductions in skin thickness and tissue weight, inflammatory cytokine production, neutrophil-mediated myeloperoxidase activity, and various histopathological indicators. Furthermore, embelin was effective at reducing inflammatory damage induced by chronic TPA exposure. Our data indicate that embelin has anti-inflammatory activities in both acute and chronic irritant contact dermatitis in vivo and this effect of embelin may be due, at least in part, to the inhibition of IL-1β and TNF-α and to the subsequent blockade of leukocyte accumulation.
Keywords: Embelin; Skin inflammation; TNF-α; Psoriasis;

Insulin resistance, oxidative stress and cytokine imbalance are key pathophysiological mechanisms in non-alcoholic fatty liver disease (NAFLD). This study aimed at evaluating the effect of treatment with the insulin sensitizer, pioglitazone, the tumor necrosis factor-α inhibitor, pentoxifylline, and the antioxidant, melatonin and their combinations in rats with NAFLD. Rats were fed a high-fat diet (HFD) for eight weeks to induce NAFLD. For an additional eight weeks, rats were fed the HFD along with pioglitazone, pentoxifylline, melatonin alone or in combination. Liver index and insulin resistance index were calculated. Serum liver enzyme activities, total cholesterol, triglycerides and tumor necrosis factor-α (TNF-α) were determined. Tissue triglycerides, malondialdehyde and reduced glutathione were measured and liver injury was evaluated by histopathological examination. HFD induced severe hepatic steatosis, inflammation and fibrosis. In addition, liver index, insulin resistance index, activities of liver enzymes and serum level of total cholesterol, triglycerides and TNF-α were elevated. This was coupled with an increase in tissue triglycerides, malondialdehyde and depletion of reduced glutathione. Pioglitazone, pentoxifylline and melatonin, alone or in combination; reduced the insulin resistance index, activities of liver enzymes, hepatic malondialdehyde and increased hepatic reduced glutathione level. Pentoxifylline led to a decrease in serum TNF-α level, however, pioglitazone and melatonin reduced serum total cholesterol and triglycerides. In conclusion, data in this study indicate that pentoxifylline and melatonin can be used as promising adjuvant therapies to pioglitazone in the clinical management of NAFLD.
Keywords: NAFLD; High-fat diet; Pioglitazone; Pentoxifylline; Melatonin;

Olive polyphenol hydroxytyrosol prevents bone loss by Keitaro Hagiwara; Tadashi Goto; Masahiro Araki; Hitoshi Miyazaki; Hiromi Hagiwara (78-84).
Polyphenols reportedly exert physiological effects against diseases such as cancer, arteriosclerosis, hyperlipidemia and osteoporosis. The present study was designed to evaluate the effects of oleuropein, hydroxytyrosol and tyrosol, the major polyphenols in olives, on bone formation using cultured osteoblasts and osteoclasts, and on bone loss in ovariectomized mice. No polyphenols markedly affected the proliferation of osteoblastic MC3T3-E1 cells at concentrations up to 10 μM. Oleuropein and hydroxytyrosol at 10 to 100 μM had no effect on the production of type I collagen and the activity of alkaline phosphatase in MC3T3-E1 cells, but stimulated the deposition of calcium in a dose-dependent manner. In contrast, oleuropein at 10 to 100 μM and hydroxytyrosol at 50 to 100 μM inhibited the formation of multinucleated osteoclasts in a dose-dependent manner. Furthermore, both compounds suppressed the bone loss of trabecular bone in femurs of ovariectomized mice (6-week-old BALB/c female mice), while hydroxytyrosol attenuated H2O2 levels in MC3T3-E1 cells. Our findings indicate that the olive polyphenols oleuropein and hydroxytyrosol may have critical effects on the formation and maintenance of bone, and can be used as effective remedies in the treatment of osteoporosis symptoms.
Keywords: Osteoporosis; Hydroxytyrosol; Ovariectomized mouse; Osteoclast; Osteoblast;