Pharmacokinetics of S-adenosyl-L-methionine in healthy volunteers

Management of neurological symptoms in Lesch-Nyhan disease: A systematic review

Lesch-Nyhan Disease (LND) is an X-linked recessive genetic disorder arising from hypoxanthine phosphoribosyltransferase 1 gene mutations, leading to a complete deficiency. LND presents a complex neurological profile characterized by generalized dystonia, motor dysfunctions and self-injurious behavior, which management is challenging. We conducted a systematic review of studies assessing the efficacy of pharmacological and non-pharmacological interventions in management of neurological symptoms in LND (PROSPERO registration number:CRD42023446513). Among 34 reviewed full-text papers; 22 studies were rated as having a high risk of bias. Considerable heterogeneity was found in studies regarding the timing of treatment implementation, adjunctive treatments and outcome assessment. Single-patient studies and clinical trials often showed contradictory results, while therapeutic failures were underreported. S-Adenosylmethionine and Deep Brain Stimulation were the most studied treatment methods and require further research to address inconsistencies. The evidence from levodopa studies underlines that optimal timing of treatment implementation should be thoroughly investigated. Standardized study design and reducing publication bias are crucial to overcome current limitations of assessing intervention efficacy in LND.

Stability and Structure of Silver–l-methionine Complexes

Stability and structure of complexes between silver (I) and l-methionine (L) deduced from potentiometric and 1H NMR measurements allow to assume the prevailing of several protonated species. The experimental data are compatible with the formation of the following complexes: AgL, AgL2, AgH2L, AgH1L2, AgH2L2, AgH3L2 and AgH4L2. The coordination sites are obtained by 1H NMR spectra, showing that only the bond between the methylthioether sulfur atom and silver (I) is responsible of the complex stability. The system is studied potentiometrically with silver and glass electrodes at 25 °C and 1.00 mol·dm−3 NaClO4 as ionic medium. Amino acids containing sulfur are few and not extensively studied. In particular, l-methionine, even if it is the most important, enantiomer and their complexes with silver (I) present anticarcinogenic properties, is quite not investigated. In the same experimental conditions, l-methionine protonation constants are determined. The 1H NMR data allow one to assume that, in moderately alkaline solution, silver (I) is bond with six membered chelate rings with sulfur and amino nitrogen, while carboxylic groups are not involved. No polynuclear species are present. The high stability of the complex with ratio 1:2 (silver (I)/l-methionine), involving also two hydrogen ions, predominating in a wide range of hydrogen ion concentration suggests to propose a study for the preparation of an electrode to measure the deprotonated l-methionine concentration.

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

The review is withdrawn as it was abandoned and has not been updated since its last edition in 2008. A new team of authors resumed the work on the review, and so far, a major update to the protocol is published. The review is expected to be finalised towards the end of 2016.

The editorial group responsible for this previously published document have withdrawn it from publication.

Pharmacokinetic properties of S-adenosylmethionine after oral and intravenous administration of its tosylate disulfate salt: a multiple-dose, open-label, parallel-group study in healthy Chinese volunteers

BACKGROUND

S-adenosylmethionine (SAMe) is an endogenous molecule that plays an important role in cellular metabolism. Despite being widely used as a dietary supplement with claimed benefits for numerous conditions, there is little information about the pharmacokinetic properties of exogenous SAMe.

OBJECTIVES

One aim of this study was to characterize the pharmacokinetic properties of SAMe after administration of single and multiple doses of orally and intravenously administered SAMe tosylate disulfate (STD) in healthy male and female Chinese volunteers. Because men have higher erythrocyte levels of endogenous SAMe than do women, we also assessed the effects of sex on the disposition of SAMe.

METHODS

A simple and sensitive assay for SAMe based on liquid chromatography-mass spectrometry using selected-ion monitoring of analyte and acyclovir as internal standard was developed and validated. The assay was used to study the pharmacokinetic properties of SAMe. STD was administered as single and multiple doses of enteric-coated tablets and IV infusion of STD to groups of healthy native Chinese volunteers. After an overnight fast, male and female Chinese volunteers were assigned to receive STD 1000 mg for 5 days, either in enteric-coated tablet formulation or as a 250-mL IV infusion. Blood samples were collected 24 hours after the first and last dose and used for determining plasma SAMe concentrations and pharmacokinetic parameters. For the oral formulation, SAMe concentrations were corrected for concentrations of endogenous SAMe. Pharmacokinetic parameters were calculated for men and women separately and for the total group of volunteers. Adverse events were monitored using a physician during blood collection and by spontaneous reporting.

RESULTS

Twenty healthy volunteers were enrolled (oral formulation: 5 men, 5 women; mean [SD] age, 24.1 [4.7] years [range, 21-37 years]; mean [SD] weight, 59.9 [4.8] kg [range, 54-70 kg]; IV formulation: 5 men, 5 women; mean [SD] age, 22.6 [1.8] years [range, 21-27 years]; mean [SD] weight, 59.5 [5.4] kg [range, 53-67 kg]). None of the between-sex differences in SAMe pharmacokinetic properties were significant. The (mean [SD]) pharmacokinetic properties of singledose oral SAMe in men and women, respectively, were as follows: C(max), 2.37 (1.58) and 2.50 (1.83) micromol/L; T(max), 5.40 (1.14) and 5.20 (1.48) hours; AUC(0-24), 8.56 (5.16) and 10.3 (8.0) micromol/L/h; and t(1/2beta), 6.06 (1.80) and 6.28 (2.60) hours. Corresponding values with the single-dose IV formulation were: C(max), 127 (49) and 211 (94) micromol/L; T(max), 1.90 (0.22) and 1.60 (0.22) hours; AUC(0-24), 329 (84) and 480 (176) micromol/L/h; and t(1/2beta), 4.34 (0.57) and 3.83 (0.78) hours. The single-dose oral:IV ratios of AUC(0-24) in men and women, respectively, were 2.60% and 2.14% (degrees of fluctuation: 4.96 [1.77] and 9.49 [0.91]). The pharmacokinetic properties of multiple-dose oral and IV SAMe were not significantly different from those with single-dose administration. None of the volunteers reported any adverse events during the study.

CONCLUSIONS

In this small study in healthy Chinese volunteers, there were no significant differences in the pharmacokinetic parameters of SAMe between men and women or between single- and multiple-dose administration of STD 1000 mg administered orally or intravenously. No evidence of accumulation of SAMe in plasma was found on multiple dosing. Both enteric-coated tablets and the IV infusion were well tolerated in these volunteers.

S-adenosyl-L-methionine for alcoholic liver diseases

BACKGROUND

Alcohol is a major cause of liver disease and disrupts methionine and oxidative balances. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione, the main cellular antioxidant. Randomised clinical trials have addressed the question whether SAMe may benefit patients with alcoholic liver diseases.

OBJECTIVES

To evaluate the beneficial and harmful effects of SAMe for patients with alcoholic liver diseases.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (May 2005), The Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 2, 2005), MEDLINE (1950 to May 2005), EMBASE (1980 to May 2005), and Science Citation Index Expanded (searched May 2005).

SELECTION CRITERIA

We included randomised clinical trials studying patients with alcoholic liver diseases. Interventions encompassed per oral or parenteral administration of SAMe at any dose versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

We performed all analyses according to the intention-to-treat method using RevMan Analyses provided by the Cochrane Collaboration. We evaluated the methodological quality of the randomised clinical trials by quality components.

MAIN RESULTS

We identified nine randomised clinical trials including a heterogeneous sample of 434 patients with alcoholic liver diseases. The methodological quality regarding randomisation was generally low, but 8 out of 9 trials were placebo controlled. Only one trial including 123 patients with alcoholic cirrhosis used adequate methodology and reported clearly on all-cause mortality and liver transplantation. We found no significant effects of SAMe on all-cause mortality (relative risks (RR) 0.62, 95% confidence interval (CI) 0.30 to 1.26), liver-related mortality (RR 0.68, 95% CI 0.31 to 1.48), all-cause mortality or liver transplantation (RR 0.55; 95% CI 0.27 to 1.09), or complications (RR 1.35, 95% CI 0.84 to 2.16), but the analysis is based mostly on one trial only. SAMe was not significantly associated with non-serious adverse events (RR 4.92; 95% CI 0.59 to 40.89) and no serious adverse events were reported.

AUTHORS' CONCLUSIONS

We could not find evidence supporting or refuting the use of SAMe for patients with alcoholic liver diseases. We need more long-term, high-quality randomised trials on SAMe for these patients before SAMe may be recommended for clinical practice.

Ademetionine (S-adenosylmethionine) neuropharmacology: implications for drug therapies in psychiatric and neurological disorders

Ademetionine (S-adenosylmethionine; SAMe) is a ubiquitous metabolite present in all cells and biological fluids, and serves as a methyl donor in a multitude of different methylation reactions involving proteins, phospholipids, catecholamines and DNA. Pharmaceutical preparations of some stable salts of SAMe are available for parenteral and oral use in humans, and have been shown to increase plasma and cerebrospinal fluid SAMe concentrations. In experimental studies administration of SAMe is associated with increases in brain monoamine neurotransmitters and b-adrenergic and muscarinic receptor functions. These neuropharmacological effects are postulated to be involved in the antidepressant activity of SAMe which has been confirmed in numerous controlled studies. Preliminary studies indicate that SAMe has therapeutic potential in the treatment of other CNS disorders including dementia, acquired immune deficiency syndrome (AIDS)-associated myelopathy, and brain ischaemia. This review will focus on recent experimental and clinical aspects of SAMe in the central nervous system, and the therapeutic use in psychiatric and neurological disorders.

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.

Double-blind, placebo-controlled cross-over study of intravenous S-adenosyl-L-methionine in patients with fibromyalgia

The objective of this study was to test the efficacy of intravenously administered S-adenosyl-L-methionine (SAMe) in patients with fibromyalgia (FM). Thirty-four out-patients with fibromyalgia symptoms received SAMe 600 mg i.v. or placebo daily for 10 days in a cross-over trial. There was no significant difference in improvement in the primary outcome: tender point change between the two treatment groups. There was a tendency towards statistical significance in favour of SAMe on subjective perception of pain at rest (p = 0.08), pain on movement (p = 0.11), and overall well-being (p = 0.17) and slight improvement only on fatigue, quality of sleep, morning stiffness, and on the Fibromyalgia Impact Questionnaire for pain. No effect could be observed on isokinetic muscle strength, Zerrsen self-assessment questionnaire, and the face scale. No effect of SAMe in patients with FM was found in this short term study.

S-adenosylmethionine levels in psychiatric and neurological disorders: a review

INTRODUCTION

S-adenosylmethionine (SAMe) is an important methyl donor in over 35 methylation reactions involving DNA, proteins, phospholipids and catechol- and indole- amines.

MATERIAL AND METHODS

This article reviews the studies that have examined brain and blood levels of SAMe in several psychological, neurological and metabolic disorders.

RESULTS

Although studies have found no consistent changes in whole blood SAMe levels in psychiatric patients, other investigators have found low cerebrospinal fluid (CSF) SAMe levels in patients with neurological disorders such as Alzheimer's dementia, subacute combined degeneration of the spinal cord (SACD), and HIV-related neuropathies, as well as in patients with metabolic disorders such as 5, 10-CH2-H4 folate reductase deficiency.

CONCLUSION

Intravenous or oral administration of SAMe thus represents a possible treatment for these neurological and metabolic disorders.

S-adenosylmethionine blood levels in major depression: changes with drug treatment

INTRODUCTION

The relationship between plasma levels of S-adenosylmethionine (SAMe), an endogenous methyl donor, and clinical response were studied in patients with a DSM-III-R diagnosis of major depression.

MATERIAL AND METHODS

A double-blind randomized protocol comparing oral SAMe with oral desipramine, involving a total of 26 patients, was employed.

RESULTS

At the end of the 4-week trial, 62% of the patients treated with SAMe and 50% of the patients treated with desipramine had significantly improved. Regardless of the type of treatment, patients with a 50% decrease in their Hamilton Depression Scale (HAM-D) score showed a significant increase in plasma SAMe concentration.

CONCLUSION

The significant correlation between plasma SAMe levels and the degree of clinical improvement in depressed patients regardless of the type of treatment suggests that SAMe may play an important role in regulating mood.

Review article: S-adenosyl-L-methionine--a new therapeutic agent in liver disease?

The established biochemical effects of exogenous S-Adenosyl-L-Methionine (SAMe) are diverse and are still being explored in liver disease. Putative therapeutic effects could be exerted via different mechanisms. The established deficiency of SAMe synthetase in cirrhosis could by bypassed by exogenous SAMe, leading to increased levels of sulphur-containing amino acids and glutathione which would protect against oxidant stress and drug-induced hepatotoxicity (for example, paracetamol). Furthermore SAMe could act by improving membrane fluidity, and thus potentially improve or restore the function of receptors, enzymes and transporters in the cell surface. Membrane fluidity is known to be affected by alterations in cell membrane lipid composition in chronic liver disease. Very few therapeutic agents are effective for the symptomatic or specific treatment of chronic liver disease. SAMe has established biochemical and biophysical effects which in pilot studies ameliorate symptoms and biochemical parameters of cholestasis. Moreover, abnormalities in liver function tests (including transaminase values) also improve. Before SAMe can be considered as an established therapy for patients with hepatic disease, long-term controlled clinical trials of SAMe are needed to assess the benefit for patients' symptoms, well being, histological changes and progression of liver disease.

Intracellular glutathione in human hepatocytes incubated with S-adenosyl-L-methionine and GSH-depleting drugs

The present study was undertaken to investigate (a) whether S-adenosyl-L-methionine (SAMe) added to culture medium can increase intracellular glutathione (GSH) levels in human hepatocytes and (b) whether SAMe can prevent the GSH depletion found in human hepatocytes incubated with GSH-depleting drugs (paracetamol, opiates, ethanol). Incubation of hepatocytes with increasing concentrations of SAMe resulted in a dose-dependent elevation of intracellular GSH content, which reached its maximum (35% increase) at 30 microM after 20 h. SAMe, as the only sulfur source in the medium, was efficient in repleting GSH-depleted hepatocytes following treatment with diethyl maleate. Incubation of human hepatocytes with SAMe attenuated the GSH depletion of cells incubated with toxic concentrations of paracetamol (2 mM), heroin (0.5 mM) and methadone (0.2 mM). A decrease in GSH due to exposure of hepatocytes to 50 mM ethanol was prevented when SAMe was simultaneously added to ethanol, and human hepatocytes maintained their GSH levels like non ethanol-treated cells. The experimental results of our work give the first direct evidence of the ability of exogenously administered SAMe to increase intracellular GSH levels in human hepatocytes and to prevent the GSH depletion caused by paracetamol, opiates and ethanol.

S-adenosylmethionine in the treatment of depression

The antidepressant property of S-adenosylmethionine (SAMe) has been supported by several uncontrolled and controlled studies. Compared to standard antidepressant agents, SAMe has fewer side-effects and shorter lag period. Future studies to delineate SAMe-responsive depression are warranted.

Neuropharmacology of S-adenosyl-L-methionine

The metabolite S-adenosyl-L-methionine (SAMe), when prepared as the stable p-toluene-sulfonate complex of its sulfate salt and given parenterally in high doses, appears to have mood-elevating effects in depressed adults. The material is remarkably well tolerated when given by injection or intravenous infusion for this purpose, even in elderly or demented patients. Assuming that the toluene sulfonate component is inert, SAMe appears to have central neuropharmacologic effects after systemic injection in high doses. Nevertheless, the functional consequences of these remain unclear and, indeed, the ability of exogenous SAMe to reach the brain, and especially neuronal cytoplasm, is limited. SAMe has small effects on monoamine metabolism and, after injection, appears to have effects on the microviscosity of cell membranes that may be related to stimulation of phospholipid synthesis. The recent introduction of an orally administered form of SAMe for use in the treatment of osteoarthritis promises to stimulate further study of SAMe in disease-associated depression, major depressive disorder, and other neuropsychiatric conditions.

Pharmacologic aspects of S-adenosylmethionine. Pharmacokinetics and pharmacodynamics

Several studies in animals have shown the efficacy of parenteral S-adenosylmethionine (SAMe) as an anti-inflammatory drug. In this article, data are reported on plasma kinetics, distribution, and metabolism of SAMe after oral administration since preference is given to oral dosage in the usual clinical practice. The results demonstrate the intestinal absorption of SAMe and its active metabolism. Experiments confirm the anti-inflammatory activity of the drug by the oral route. Results are also reported on the analgesic effect of SAMe.