Long-term risperidone treatment induces visceral adiposity associated with hepatic steatosis in mice: a magnetic resonance approach.

Although atypical antipsychotic drugs (APDs) have led to significant advances in the treatment of psychotic disorders, they still induce metabolic disturbances. We aimed at characterizing the metabolic consequences of a risperidone treatment and at establishing a link with noninvasive MR markers, in order to develop a tool for predicting symptoms of the metabolic syndrome. Fat deposition and liver morphometry were assessed by T1-weighted imaging. Fatty acid composition and fat accumulations in tissues were determined using MR spectroscopy with and without water suppression, respectively. Risperidone treatment induced a weight gain accompanied with metabolic disturbances such as hyperglycemic status, an increase in visceral adipose tissue (VAT), and liver fat depositions. Correlations using Methylene-Water Ratio (MWR) and Polyunsaturated Index (PUI) demonstrated a concomitant increase in the weight gain, VAT and liver fat depositions, and a decrease in the quantity of polyunsaturated fatty acids. These results were consistent with a hepatic steatosis state. We evaluated the ability of MR techniques to detect subtle metabolic disorders induced by APDs. Thus, our model and methodology offer the possibility to investigate APDs side effects in order to improve the health conditions of schizophrenic patients.

Fenofibrate inhibits endothelin-1 expression by peroxisome proliferator-activated receptor α-dependent and independent mechanisms in human endothelial cells.

OBJECTIVE: Dyslipidemia contributes to endothelial dysfunction in type 2 diabetes mellitus. Fenofibrate (FF), a ligand of the peroxisome proliferator-activated receptor-α (PPARα), has beneficial effects on microvascular complications. FF may act on the endothelium by regulating vasoactive factors, including endothelin-1 (ET-1). In vitro, FF decreases ET-1 expression in human microvascular endothelial cells. We investigated the molecular mechanisms involved in the effect of FF treatment on plasma levels of ET-1 in type 2 diabetes mellitus patients. METHODS AND RESULTS: FF impaired the capacity of transforming growth factor-ß to induce ET-1 gene expression. PPARα activation by FF increased expression of the transcriptional repressor Krüppel-like factor 11 and its binding to the ET-1 gene promoter. Knockdown of Krüppel-like factor 11 expression potentiated basal and transforming growth factor-ß-stimulated ET-1 expression, suggesting that Krüppel-like factor 11 downregulates ET-1 expression. FF, in a PPARα-independent manner, and insulin enhanced glycogen synthase kinase-3ß phosphorylation thus reducing glycogen synthase kinase-3 activity that contributes to the FF-mediated reduction of ET-1 gene expression. In type 2 diabetes mellitus, improvement of flow-mediated dilatation of the brachial artery by FF was associated with a decrease in plasma ET-1. CONCLUSIONS: FF decreases ET-1 expression by a PPARα-dependent mechanism, via transcriptional induction of the Krüppel-like factor 11 repressor and by PPARα-independent actions via inhibition of glycogen synthase kinase-3 activity.

Antioxydant activity of ß-carboline derivatives in the LDL oxidation model.

A series of ß-carboline compounds were synthesized, starting from compound GWC22, their antioxidant activity was determined by inhibition of lipid peroxidation. The oxidation of LDL was induced in the presence of CuSO4 or 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). The protective actions of these compounds against the cytotoxicity were evaluated with lactate dehydrogenase (LDH) activity in bovine aortic endothelial cells (BAECs) and cellular vitality by measuring mitochondrial activity in the presence of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). Most of compounds showed an higher antioxidant activity than GWC22 derivative (R=1.6 for 5 µM CuSO4). The best antioxidant activities are phenolic and benzyloxy derivatives with ratio R=1.9 to 2.8 for 1 µM CuSO4. These substances have protective actions and increase significantly the cell viability.

Antioxidant activity of benzoxazolinonic and benzothiazolinonic derivatives in the LDL oxidation model.

A series of benzazolone compounds were synthesized utilizing benzoxazolinonic and benzothiazolinonic heterocycles as the building unit. The antioxidant activity of these compounds was determined by inhibition of lipid peroxidation. The oxidation of LDL was induced in the presence of CuSO(4) or 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). The protective action of these compounds against the cytotoxicity was evaluated with lactate dehydrogenase (LDH) activity in bovine aortic endothelial cells (BAECs) and cellular vitality by measuring mitochondrial activity in the presence of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). The best antioxidant activities were observed for phenolic compounds 13 and 14b with ratio R=2.5, 3.2 (5microM). Both of these test substances increased the cell viability significantly as indicated by MTT assay and LDH release assay.

Vasorelaxant and anti-platelet aggregation effects of aqueous Ocimum basilicum extract.

AIM OF THE STUDY: In this work the endothelium-dependant vasorelaxant and anti-platelet aggregation activities of an aqueous extract from Ocimum basilicum were studied. MATERIALS AND METHODS: The vasorelaxant effect was undertaken in thoracic aorta from three experimental groups of rats: one of them (NCG) fed with standard diet, the second (HCG) with hypercholesterolemic diet (HCD) and the third (BTG) with hypercholesterolemic diet together with an intragastric administration of Ocimum basilicum extract at a dose of 0.5 g/kg body weight for a period of 10 weeks. The in vitro anti-platelet aggregation of Ocimum basilicum extract was studied using thrombin (0.5 U/ml) and ADP (5 microM) as agonists. RESULTS: The results show that the HCD statistically decreases vascular relaxation in HCG compared to NCG (p<0.001) and increases the vascular responses to phenylephrine (p<0.02). Ocimum basilicum extract exerts a significant vasorelaxant effect at 10(-5) M (p<0.01) and 10(-4) M carbachol (p=0.001). The plant extract also tends to suppress the elevated contractions induced by HCD (p=0.05). The extract inhibits ADP-induced platelet aggregation by 13%, 28.2%, 30.5%, 44.7% and 53% at a dose of 1, 2, 3, 4 and 5 g/l, respectively. Thrombin-induced platelet activation was also reduced by 15%, 23%, 40%, 38.4%, and 42% at the same doses of extract described above. CONCLUSION: The use of Ocimum basilicum as medicinal plant could be beneficial for cardiovascular system.

Effects of Microdesmis keayana alkaloids on vascular parameters of erectile dysfunction.

Microdesmis keayana (Pandaceae) is an African tropical plant whose roots are used in traditional medicine for erection impairment but the compounds responsible for its action are unknown. Two major alkaloids recently isolated from the roots of M. keayana, keayanidine B and keayanine, were tested for vasorelaxing properties using isolated rat aortic rings precontracted by phenylephrine to confirm its traditional use. Influence of the alkaloids on the endothelial production of endothelial nitric oxide synthase (eNOS) was measured by quantitative polymerase chain reaction (QPCR) analysis. Scavenging activities were assessed versus 1,1-diphenyl-2-picrylhydrazyle (DPPH) and reactive oxygen species (ROS) such as superoxide anion (O(2)(*-) and hydrogen peroxide (H(2)O(2)) in cell-free and cellular systems. The results showed that keayanidine B and keayanine had significant vasorelaxing properties. This effect could be due to their strong antioxidant activity versus O(2)(*-) and H(2)O(2) and to their stimulation of eNOS mRNA expression. Therefore these alkaloids could indirectly stimulate NO production in the vascular bed and would explain the traditional use of M. keayana in erectile dysfunction.

Vasoactivity, antioxidant and aphrodisiac properties of Caesalpinia benthamiana roots.

AIMS OF THE STUDY: Caesalpinia benthamiana (=Mezoneuron benthamianum) (Fabaceae) is an African tropical plant whose roots are used in traditional medicine as an aqueous decoction for many purposes, especially for erection impairment but its action mechanism is unknown. The action of Caesalpinia benthamiana on sexual behaviour and some assays on potential modes of action were performed. MATERIALS AND METHODS: The aqueous extract of Caesalpinia benthamiana (AECB) was tested for vasorelaxing properties using isolated rat aortic rings precontracted by phenylephrine. Influence of AECB in the production of endothelial isoform of nitric oxide synthase (eNOS) was measured by quantitative polymerase chain reaction (QPCR) analysis. Scavenging activities versus reactive oxygen species (ROS), such as superoxide anion (O(2).(-)), hydrogen peroxide (H(2)O(2)), and hypochlorous acid (HOCl) were assessed. Action of AECB on the cellular generation of O(2).(-) was also tested in a physiopathology model of oxidative burst using human polymorphonuclear neutrophils stimulated by phorbol myristate acetate. The aphrodisiac properties of AECB administered orally by gavage (50 mg/kg body weight) to male rats were evaluated by observing the sexual behaviour of animals. Finally, a short-term toxicity study was undertaken to establish the therapeutic index of AECB administered orally to rats at high dose (2 g/kg body weight). RESULTS: C. benthamiana roots are rich in phenolic compounds (gallic acid, resveratrol and tannins). The results showed that AECB had significant vasorelaxing properties. The extract also had a strong radical activity against ROS in cell-free and cellular systems and stimulated eNOS mRNA expression. As for the aphrodisiac activity of AECB in male rats, results have shown that sexual parameters are stimulated. Furthermore, after oral administration at high dose, AECB causes no mortality or changes in rats' behaviour. CONCLUSION: AECB enhanced the sexual activity of male rats. This could be partly explained by its vasorelaxant properties, which may be caused by an increase in NO production in vascular bed and a decrease in its destruction.

The PPARalpha activator fenofibrate slows down the progression of the left ventricular dysfunction in porcine tachycardia-induced cardiomyopathy.

It has been reported that high intramyocardial peroxisome proliferator-activated receptor alpha (PPARalpha) stimulation or overexpression altered cardiac contractile function in mouse models of cardiac hypertrophy and heart failure. Nevertheless, it has never been demonstrated that clinically relevant doses of drugs stimulating PPARalpha activity such as fenofibrate increase the risk to develop heart failure in humans. To determine if fenofibrate accelerates the development of heart failure in large mammals, we have tested its effects on the progression of left ventricular dysfunction in pacing-induced heart failure in pigs. Fenofibrate treatment blunted reduction in left ventricular ejection fraction, reduced cardiac hypertrophy, and attenuated clinical signs of heart failure. Fenofibrate impeded the increase in atrial natriuretic peptide, brain natriuretic peptide, and endothelin-1 plasma levels. The expression of PPARalpha, fatty acyl-CoA-oxidase, and carnitine palmitoyltransferase-Ibeta was reduced at mRNA levels in the left ventricle from untreated heart failure pigs but maintained near normal values with fenofibrate. Fenofibrate prevented heart failure-induced overexpression of TNFalpha mRNA and enhanced catalase activity in left ventricle compared to placebo. These data suggest that a clinically relevant dose of fenofibrate does not accelerate but slows down heart failure development in the model of pacing-induced heart failure in large mammals.

PON1, a new biomarker of cardiovascular disease, is low in patients with systemic vasculitis.

OBJECTIVES: Because systemic vasculitis (SV) predisposes to atherosclerosis, and high-density lipoprotein (HDL) prevents atherosclerosis by "reverse cholesterol transport" and by inhibiting low-density lipoprotein (LDL) oxidation thanks to apolipoprotein A-I (Apo-AI) and paraoxonase 1 (PON1), we assessed whether LDL oxidation was increased in SV and associated with less PON1 activity. METHODS: The sera of 33 patients with active SV (ASV), 32 in full remission of SV (RSV) and 20 healthy subjects (HS) were analyzed for C-reactive protein (CRP), high-sensitivity-CRP, lipids, lipoproteins, apolipoproteins, PON1 activity, LDL-immune complexes (LDL-IC), and auto-antibodies to oxidized-LDL (ox-LDL), and anticardiolipin antibodies. RESULTS: CRP was higher in ASV than RSV and HS, and negatively correlated with HDL-cholesterol and Apo-AI. Autoantibodies to ox-LDL and highly oxidized malondialdehyde-LDL were higher in RSV than ASV and HS (P<0.05). LDL-IC titers were higher in ASV than RSV and HS (P<0.05). PON1 activity was lower in ASV and RSV than HS (P=0.02). A trend toward a negative correlation between basal PON1 activity and anti-MDA-LDL antibodies (P=0.06) was observed. CONCLUSION: Inflammatory markers in SV were associated with a modified lipoprotein profile, which could lower PON1 activity and contribute to increased ox-LDL titers and accelerated atherosclerosis development.

Paullinia pinnata extracts rich in polyphenols promote vascular relaxation via endothelium-dependent mechanisms.

Paullinia pinnata L. (Sapindaceae) is an African tropical plant whose roots and leaves are used in traditional medicine for many purposes, especially for erectile dysfunction, but its action mechanism is unknown. P. pinnata root and leaf methanolic extracts are rich in phenolic compounds. This study shows that both extracts are highly antioxidative and induce a slight transcriptional activity of peroxisome proliferator activated receptor-alpha. They also increased and decreased endothelial nitric oxide synthase and endothelin-1 mRNA levels in bovine aortic endothelial cells, respectively. In this study P. pinnata methanolic extracts in cumulative doses elicited in a dose-dependent manner the relaxation of phenylephrine precontracted isolated rat aortic rings. N-nitro-L-arginine methyl ester significantly attenuated the capacity of both extracts to induce arterial relaxation, indicating that this arterial relaxation was mediated by endothelial nitric oxide release. It could be suggested that the arterial relaxation induced by both extracts could be mainly linked to their capacities to inhibit nitric oxide oxidation through their antioxidant properties.

Vasoactivity and antioxidant properties of Microdesmis keayana roots.

Endothelial isoform of nitric oxide synthase (eNOS) mRNA expression increases in the corpora cavernosum, penile arteries and arterioles during erection. But eNOS expression and nitric oxide (NO), the product of its catalytic action, are inactivated by reactive oxygen species (ROS), especially by superoxide anion. ROS are involved in the impairment of endothelium-dependent relaxation and are responsible for some of the pathologies linked to erectile dysfunction (i.e. hypertension, atherosclerosis, etc.). While investigating Microdesmis keayana J. Léonard (Pandaceae) (syn. Microdesmis puberula Hook.f. ex. Planch.), used in African traditional medicine for erectile dysfunction, the hypotensive and the vasorelaxing properties of the aqueous extract of Microdesmis keayana (AEMK) were, respectively, tested using normotensive rabbits and aorta strips of guinea pigs in an organ bath experience. Interaction of AEMK in endothelial production of eNOS was measured by the quantitative polymerase chain reaction (QPCR) analysis. The scavenging activities versus ROS, such as superoxide anion (O(2)(.-)), hydrogen peroxide (H(2)O(2)), hypochlorous acid (HOCl) and hydroxyl radical (HO.) were evaluated. Action of AEMK on cellular generation of superoxide anion was also tested in a physiopathology model of oxidative burst using human polymorphonuclear neutrophils (PMNs) stimulated by phorbol myristate acetate. The results showed that Microdesmis keayana roots had significant hypotensive and vasorelaxing properties. These properties are due to both antioxidant activities and stimulation of eNOS mRNA expression. Therefore, AEMK stimulated indirectly NO production in the vascular bed.

Increased susceptibility of low-density lipoprotein to ex vivo oxidation in mice transgenic for human apolipoprotein B treated with 1 melatonin-related compound is not associated with atherosclerosis progression.

Considerable evidence supports the hypothesis that LDL oxidation has an important role in atherosclerosis. It has been demonstrated that the feeding of hypercholesterolemic mice on an atherogenic diet supplemented with melatonin highly increases the surface of atherosclerotic lesions in aorta and the sensitivity of atherogenic lipoprotein to ex vivo oxidation even though high melatonin doses inhibit lipoprotein oxidation in vitro. A melatonin-related compound (DTBHB: N-[2-(5-methoxy-1H-indol-3-yl)ethyl]-3,5-di-tert-butyl-4-hydroxybenzamide) has been reported to strongly inhibit lipid peroxidation in vitro. In the present study, DTBHB treatment considerably increased the sensitivity of atherogenic lipoproteins to ex vivo oxidation but did not modify atherosclerotic lesion development in mice. Moreover, DTBHB treatment did not induce detectable lipidic alteration. These data confirm that the capacity of molecules to inhibit atherogenic lipoprotein oxidation in vitro offers no prediction of their capacity to inhibit in vivo atherosclerosis development.

Natural phenylpropanoids inhibit lipoprotein-induced endothelin-1 secretion by endothelial cells.

There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherosclerosis. Endothelin-1 (ET-1) is a potent vasoconstrictor peptide isolated from endothelial cells and it induces smooth muscle cell proliferation. ET-1 secretion is increased in atheroma and induces deleterious effects such as vasospasm and atherosclerosis. The goal of this study was to test the effect of four natural phenolic compounds against copper-oxidized LDL (Cu-LDL)-induced ET-1 liberation by bovine aortic endothelial cells (BAEC). The tested compounds were phenylpropanoid glycosides previously isolated from the aerial parts of Marrubium vulgare L. (acteoside 1, forsythoside B 2, arenarioside 3 and ballotetroside 4). ET-1 secretion increased when cells were incubated with Cu-LDL but the compounds 1-4 inhibited this increase. These results were confirmed by quantitative-polymerase chain reaction (QPCR) analysis. Since ET-1 plays an important role in atherosclerosis development, our work suggests that the tested phenylpropanoids could have a beneficial effect in inhibiting atherosclerosis development.

Natural phenylpropanoids protect endothelial cells against oxidized LDL-induced cytotoxicity.

There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherosclerosis. Minimally oxidized LDL (mOx-LDL) induce cytotoxicity in cultured bovine aortic endothelial cells (BAEC). The goal of this study was to test the protective effect of five natural polyphenols isolated from the aerial parts of Marrubium vulgare L. against mOx-LDL-induced cytotoxicity in BAEC. Four phenylpropanoid glycosides (acteoside 1, forsythoside B 2, arenarioside 3, ballotetroside 4) and one non-glycosidic derivative (caffeoyl-l-malic acid 5) were tested. These compounds inhibited both copper (Cu 2+)- and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced in vitro LDL oxidation and preserved the morphological aspects of BAEC during their incubation with mOx-LDL. Furthermore, they reduced the accumulation of aldehydes in the cultured medium during the incubation of BAEC with mOx-LDL and prevented cellular LDH leakage during this period. These data suggest that natural phenylpropanoids inhibit mOx-LDL-induced cellular toxicity and that inhibition of lipid peroxidation could be a key mechanism in the cytoprotective effect of these molecules.