Effects Of S-adenosyl-L-methionine Research Articles

WITHDRAWN: S-adenosyl-L-methionine for alcoholic liver diseases.

Background Alcohol is a major cause of liver disease in the Western world today. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for all known biological methylation reactions and participates in the synthesis of glutathione, the main cellular anti-oxidant. Randomised clinical trials have addressed the question whether SAMe has any efficacy in patients with alcoholic liver diseases. Objectives The objectives were to assess the efficacy of SAMe on mortality, clinical symptoms, complications, liver biochemistry, and liver histology in patients with alcoholic liver diseases. Adverse events were also analysed. Search strategy The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Library, MEDLINE, EMBASE, and full text searches were combined. Selection criteria Randomised clinical trials studying patients with alcoholic liver diseases were included. Interventions encompassed peroral or parenteral administration of SAMe at any dose versus placebo or no intervention. The trials could be double blind, single blind, or unblinded. The trials could be unpublished or published as an article, an abstract, or a letter, and no language limitations were applied. Data collection and analysis All analyses were performed according to the intention-to-treat method. The statistical package (RevMan and MetaView) provided by the Cochrane Collaboration was used. The methodological quality of the randomised clinical trials was evaluated by components of quality and the Jadad-score. Main results Eight placebo-controlled randomised clinical trials including a heterogeneous sample of 330 patients with alcoholic liver disease were identified. Only one trial including 123 patients with alcoholic cirrhosis used adequate methodology and reported clearly on mortality and liver transplantation. It demonstrated no significant effects of SAMe on mortality (Peto odds ratio (OR) 0.53, 95% confidence interval (CI) 0.22 to 1.29), liver related mortality (OR 0.63, 95% CI 0.25 to 1.58), mortality or liver transplantation (OR 0.47; 95% CI 0.20 to 1.09), or patients without complications (OR 0.63, 95% CI 0.30 to 1.31). SAMe was not significantly associated with adverse events (OR 3.95, 95% CI 0.77 to 20.24). Reviewer's conclusions This systematic review could not demonstrate any significant effect of SAMe on mortality, liver related mortality, mortality or liver transplantation, and liver complications of patients with alcoholic liver disease. SAMe should not be used for alcoholic liver disease outside randomised clinical trials.

S-ADENOSYL-L-METHIONINE ATTENUATES OXIDATIVE STRESS AND HEPATIC STELLATE CELL ACTIVATION IN AN ETHANOL-LPS-INDUCED FIBROTIC RAT MODEL

Previous studies report S-adenosyl-L-methionine (SAMe) can exert hepatoprotective effects. At present, the role of SAMe in affecting the activation and/or proliferation of hepatic stellate cells (HSCs) during alcohol-induced fibrotic disease progression is poorly understood. In the human disease state, chronic ethanol intake increases hepatic exposure to LPS and magnifies the hepatic insult leading to fibrosis and cirrhosis. In this study, we developed a "2-hit" ethanol-LPS fibrotic liver rat model with which to investigate the effects of SAMe as a hepatic antifibrotic treatment. Male rats were maintained on liquid diets containing either ethanol or isocalorically matched controls for 8 weeks. Animals received ethanol alone (E), ethanol concomitant with twice weekly LPS injections (EL), or ethanol, LPS, and daily SAMe injections. When using this model, SAMe-treated animals demonstrated significantly decreased fibrosis, oxidative stress, steatosis, and improved liver function versus the EL group. In addition, the EL group showed increased HSC activation, an effect that was abrogated by the addition of SAMe. Analysis of the transforming growth factor-beta (TGF-beta) signaling pathways demonstrated increased hepatic TGF-beta and Smad3 messenger RNA expression in the E and EL groups, which was inhibited in the presence of SAMe. Conversely, SAMe led to increased Smad7 (an inhibitor of TGF-beta signaling) messenger RNA expression. These data demonstrate chronic ethanol feeding combined with LPS induces liver fibrosis, and the addition of SAMe significantly reduces hepatic injury and fibrosis through inhibition of oxidative stress and HSC activation.

S-ADENOSYL-L-METHIONINE ATTENUATES LIVER INJURY IN AN ALCOHOL-LPS MODEL

In vivo studies have shown that chronic alcoholism sensitizes the liver to endotoxemic shock leading to liver microcirculation disruption. Both LPS and chronic ethanol consumption increased hepatic sinusoidal contractile response to the constrictor effects of endothelin-1 (ET-1). The antioxidant S-adenosyl-L-methionine (SAMe) can attenuate and even prevent acute liver injury but very little is known about its role in chronic inflammatory disease progression. In this study we attempted to study the potential beneficial effects of SAMe on the liver microcirculation regulation in an alcohol-induced liver injury model. Male Sprague-Dawley rats were fed an alcohol liquid diet or a control isocaloric diet for 7 weeks with or without a daily injection of SAM (10 mg/kg b.w. i.p). Priming effects of ethanol were studied in a model with or without a semiweekly LPS treatment (1 mg/kg b.w. i.p.). At the end of the diet, animals receiving chronic ethanol and LPS (E-LPS) had an extensive steatosis and a mild infiltration as well as high levels of ALT and gained 66% more weight than animals under SAMe treatment (E-LPS-S). SAMe also significantly attenuated the steatohepatitis and liver injury as shown by the histology and the ALT levels. Alcohol feeding combined to a semiweekly LPS injection for 7 weeks resulted in HSC activation (upregulation of smooth muscle alpha actin, TGF beta and ET-1 RNA levels), and an upregulation of Caveolin-1. SAMe significantly decreased all these parameters when added to the alcohol and LPS treatment. In conclusion, our results demonstrate that chronic alcohol feeding combined with semiweekly LPS injection can induce a moderate liver fibrosis and injury combined with an imbalance in regulators of the liver microcirculation. Addition of SAMe to this chronic insult was able to significantly reduce hepatic injury and restore the balance of hepatic vasoregulators. These results suggest a close link between vascular dysregulation and progression of alcohol/LPS-induced liver injury. Supported by NIH grants AA14891 and DK38201.

Opposite action ofS-adenosyl methionine and its metabolites on CYP2E1-mediated toxicity in pyrazole-induced rat hepatocytes and HepG2 E47 cells

S-adenosyl-L-methionine (SAMe) is protective against a variety of hepatotoxins, including ethanol. The ability of SAMe to protect against cytochrome P-450 2E1 (CYP2E1)-dependent toxicity was studied in hepatocytes from pyrazole-treated rats and HepG2 E47 cells, both of which actively express CYP2E1. Toxicity was initiated by the addition of arachidonic acid (AA) or by depletion of glutathione after treatment with L-buthionine sulfoximine (BSO). In pyrazole hepatocytes, SAMe (0.25-1 mM) protected against AA but not BSO toxicity. SAMe elevated GSH levels, thus preventing the decline in GSH caused by AA, and SAMe prevented AA-induced lipid peroxidation. SAMe analogs such as methionine or S-adenosyl homocysteine, which elevate GSH, also protected against AA toxicity. 5'-Methylthioadenosine (MTA), which cannot produce GSH, did not protect. The toxicity of BSO was not prevented by SAMe and the analogs because GSH cannot be synthesized. In contrast, in E47 cells, SAMe and MTA but not methionine or S-adenosyl homocysteine potentiated AA and BSO toxicity. Antioxidants such as trolox or N-acetyl cysteine prevented this synergistic toxicity of SAMe plus AA or SAMe plus BSO, respectively. In pyrazole hepatocytes, SAMe prevented the decline in mitochondrial membrane potential produced by AA, whereas in E47 cells, SAMe potentiated the decline in mitochondrial membrane potential. In E47 cells, but not pyrazole hepatocytes, the combination of SAMe plus BSO lowered levels of the antioxidant transcription factor Nrf2. Because SAMe can be metabolized enzymatically or spontaneously to MTA, MTA may play a role in the potentiation of AA and BSO toxicity by SAMe, but the exact mechanisms require further investigation. In conclusion, contrasting effects of SAMe on CYP2E1 toxicity were observed in pyrazole hepatocytes and E47 cells. In hepatocytes, SAMe protects against CYP2E1 toxicity by a mechanism involving maintaining or elevating GSH levels.

Double-blind, placebo-controlled pharmacodynamic studies with a nutraceutical and a pharmaceutical dose of ademetionine (SAMe) in elderly subjects, utilizing EEG mapping and psychometry

In a double-blind, placebo-controlled crossover study, the effects of S-adenosyl- l-methionine (SAMe) on brain function measures of 12 normal elderly volunteers (6 m/6 f, aged 57–73 years, mean: 61 years) were investigated by means of EEG mapping and psychometry. In random order, the subjects were orally administered a pharmaceutical dose of 1600 mg SAMe, a nutraceutical dose of 400 mg SAMe and placebo, each over a period of 15 days, with wash-out periods of 2 weeks in between. EEG recordings, psychometric tests and evaluations of tolerability and side effects were carried out 0, 1, 3 and 6 h after drug administration on days 1 and 15. Multivariate analysis based on MANOVA/Hotelling T 2 tests of quantitative EEG data demonstrated significant central effects of SAMe as compared with placebo after acute, subacute and superimposed drug administration of both the nutraceutical and the pharmaceutical dose. EEG changes induced by SAMe were characterized by an increase in total power, a decrease in absolute and relative power in the delta/theta and slow alpha frequencies, an increase in absolute and relative power in the alpha-2 and beta frequencies as well as an acceleration of the alpha centroid and the centroid of the total power spectrum. The delta/theta and the beta centroid showed variable changes over time. The dominant alpha frequency was accelerated, the absolute and relative power in the dominant alpha frequency attenuated after SAMe as compared with placebo. These acute and subacute pharmaco-EEG findings in elderly subjects are typical of activating antidepressants. Time-efficacy calculations showed that acute oral administration of SAMe in both the nutraceutical and the pharmaceutical dose induced the pharmacodynamic peak effect in the first hour with a subsequent decline. The 3rd and 6th hours still showed a significant encephalotropic effect after the 1600 mg dose. The maximum EEG effect was noted after 2 weeks of oral administration of both 1600 mg/die and 400 mg/die. The superimposed dose induced significant encephalotropic effects in the 3rd hour after 400 mg and in the 3rd and 6th hours after 1600 mg as compared with pre-treatment. Dose-efficacy calculations showed that the pharmaceutical dose of 1600 mg had a more pronounced effect on the CNS than the nutraceutical dose of 400 mg, with both doses being superior to placebo. Psychometric tests concerning noopsychic and thymopsychic measures as well as critical flicker fusion frequency generally demonstrated a lack of differences between SAMe and placebo, which reflects a good tolerability of the drug in elderly subjects. This was corroborated by the findings on side effects, pulse and blood pressure.

S-adenosyl-L-methionine for alcoholic liver diseases.

Alcohol is a major cause of liver disease in the Western world today. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for all known biological methylation reactions and participates in the synthesis of glutathione, the main cellular anti-oxidant. Randomised clinical trials have addressed the question whether SAMe has any efficacy in patients with alcoholic liver diseases. The objectives were to assess the efficacy of SAMe on mortality, clinical symptoms, complications, liver biochemistry, and liver histology in patients with alcoholic liver diseases. Adverse events were also analysed. The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Library, MEDLINE, EMBASE, and full text searches were combined. Randomised clinical trials studying patients with alcoholic liver diseases were included. Interventions encompassed peroral or parenteral administration of SAMe at any dose versus placebo or no intervention. The trials could be double blind, single blind, or unblinded. The trials could be unpublished or published as an article, an abstract, or a letter, and no language limitations were applied. All analyses were performed according to the intention-to-treat method. The statistical package (RevMan and MetaView) provided by the Cochrane Collaboration was used. The methodological quality of the randomised clinical trials was evaluated by components of quality and the Jadad-score. Eight placebo-controlled randomised clinical trials including a heterogeneous sample of 330 patients with alcoholic liver disease were identified. Only one trial including 123 patients with alcoholic cirrhosis used adequate methodology and reported clearly on mortality and liver transplantation. It demonstrated no significant effects of SAMe on mortality (Peto odds ratio (OR) 0.53, 95% confidence interval (CI) 0.22 to 1.29), liver related mortality (OR 0.63, 95% CI 0.25 to 1.58), mortality or liver transplantation (OR 0.47; 95% CI 0.20 to 1.09), or patients without complications (OR 0.63, 95% CI 0.30 to 1.31). SAMe was not significantly associated with adverse events (OR 3.95, 95% CI 0.77 to 20.24). This systematic review could not demonstrate any significant effect of SAMe on mortality, liver related mortality, mortality or liver transplantation, and liver complications of patients with alcoholic liver disease. SAMe should not be used for alcoholic liver disease outside randomised clinical trials.

S-adenosyl-L-methionine prevents disruption of canalicular function and pericanalicular cytoskeleton integrity caused by cyclosporin A in isolated rat hepatocyte couplets.

Isolated rat hepatocyte couplets were used to study the effect of S-adenosyl-L methionine (SAMe) treatment on disruption of canalicular function caused by cyclosporin A (CyA). Canalicular function was assessed by counting the percentage of couplets that were able to accumulate the fluorescent cholephile choly-lysyl-fluorescein (CLF) into the canalicular vacuole between the two cells, i.e., canalicular vacuole accumulation (CVA). Cotreatment with 1 mmol/L SAMe prevented the inhibition of canalicular vacuole accumulation caused by CyA (75 nmol/L and 100 nmol/L), whereas treatment with it after CyA was unsuccessful. SAMe prevented the dose dependent reduction caused by CyA (5 nmol/L-1 mumol/L) both on CVA and on retention of CLF preaccumulated within the canaliculus, the effect on retention being complete. No difference in intracellular content of reduced glutathione (GSH) between the control and any dose level of the immunosuppressor, with or without SAMe treatment was observed, suggesting that changes in intracellular reduced GSH levels are not involved in the effects of SAMe. F-actin was stained with fluorescein-isothiocyanate phalloidin and fluorescence measurements were performed by confocal microscopy. The ratio of the percanalicular area fluorescence/total couplet fluorescence, indicative of F-actin distribution, significantly decreased with CyA. However, cotreatment of CyA with SAMe protected the integrity of the pericanalicular cytoskeleton, suggesting that this beneficial effect on canalicular function may maintain canalicular contractions and/or preserve tight junction function. Results are discussed in relation to possible involvement of the transmethylation pathway, modifications in membrane fluidity, effects on bile acid transport, and of inhibition of uptake of CyA. They suggest that SAMe could be a good candidate for protecting against CyA-induced membrane dysfunction.

S-adenosyl-L-methionine prevents disruption of canalicular function and pericanalicular cytoskeleton integrity caused by cyclosporin A in isolated rat hepatocyte couplets

Isolated rat hepatocyte couplets were used to study the effect of S-adenosyl-L methionine (SAMe) treatment on disruption of canalicular function caused by cyclosporin A (CyA). Canalicular function was assessed by counting the percentage of couplets that were able to accumulate the fluorescent cholephile choly-lysyl-fluorescein (CLF) into the canalicular vacuole between the two cells, i.e., canalicular vacuole accumulation (CVA). Cotreatment with 1 mmol/L SAMe prevented the inhibition of canalicular vacuole accumulation caused by CyA (75 nmol/L and 100 nmol/L), whereas treatment with it after CyA was unsuccessful. SAMe prevented the dose dependent reduction caused by CyA (5 nmol/L-1 mumol/L) both on CVA and on retention of CLF preaccumulated within the canaliculus, the effect on retention being complete. No difference in intracellular content of reduced glutathione (GSH) between the control and any dose level of the immunosuppressor, with or without SAMe treatment was observed, suggesting that changes in intracellular reduced GSH levels are not involved in the effects of SAMe. F-actin was stained with fluorescein-isothiocyanate phalloidin and fluorescence measurements were performed by confocal microscopy. The ratio of the percanalicular area fluorescence/total couplet fluorescence, indicative of F-actin distribution, significantly decreased with CyA. However, cotreatment of CyA with SAMe protected the integrity of the pericanalicular cytoskeleton, suggesting that this beneficial effect on canalicular function may maintain canalicular contractions and/or preserve tight junction function. Results are discussed in relation to possible involvement of the transmethylation pathway, modifications in membrane fluidity, effects on bile acid transport, and of inhibition of uptake of CyA. They suggest that SAMe could be a good candidate for protecting against CyA-induced membrane dysfunction. (Hepatology 1996 Jul;24(1):134-40)

Effect of S-adenosyl-L-methionine on cerebral monoamine turnover after hypoxia in rats

The effects of S-Adenosyl-L-methionine (SAMe) on cerebral monoamine turnover at 60 min of reoxygenation after hypoxia (PaO2, 31-35 mmHg) for 15 min were studied in 44 rats anesthetized with nitrous oxide. The accumulations of monoamine metabolites: 3-methoxy 4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined after probenecid. The accumulations of noradrenaline (NA) and dopamine (DA) were also determined after pargyline. In the non-treated group, there was an impairment of degradation of NA to MHPG and of DA to DOPAC or HVA in the control group (no hypoxia). These changes were accompanied by higher levels of NA and DA in the cerebral cortex, hypothalamus and striatum than those of the control group. In the group treated with 100 mg/kg SAMe plus 38 mg/kg mannitol 3 min after the start of reoxygenation, there were no significant changes in these metabolites and amines. Mannitol alone did not cause significant changes. There were no changes in serotonin and 5-HIAA in any of the groups studied. The effects of SAMe were studied in an additional 16 awake rats. MHPG in all regions measured after probenecid in the rats treated with SAMe was higher than that without SAMe. It appears that SAMe ameliorates perturbation of cerebral catecholamine turnover produced by reoxygenation after hypoxia.

Effects of S-adenosyl-L-methionine on the behavior of mice.

The present work was prompted by recent clinical observations (4), in which antidepressant effects were claimed for S-adenosyl-L-methionine (SAMe). Our work was designed to explore the effects of SAMe on the behavior of experimental animals — namely, on mice treated with the substance either alone or associated with other drugs endowed with actions on the CNS. The animals were then exposed to experimental situations such as are usually implemented for the screening of psychoactive drugs. We chose this experimental design in an attempt to define the behavioral effects of SAMe in comparison with those of the tricyclic antidepressants.KeywordsUnconditional StimulusAvoidance ResponseDaily SessionAvoidance LearningSpontaneous Motor ActivityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.