N-ацетилцистеин как корректор раздражительности при детском аутизме

Background

This study examined the efficacy and safety of N-acetylcysteine (NAC) augmentation for treating irritability in children and adolescents with autism spectrum disorders (ASD).

Method

Forty children and adolescents met diagnostic criteria for ASD according to DSM-IV. They were randomly allocated into one of the two groups of NAC (1200mg/day)+risperidone or placebo+risperidone. NAC and placebo were administered in the form of effervescent and in two divided doses for 8 weeks. Irritability subscale score of Aberrant Behavior Checklist (ABC) was considered as the main outcome measure. Adverse effects were also checked.

Results

The mean score of irritability in the NAC+risperidone and placebo+risperidone groups at baseline was 13.2(5.3) and 16.7(7.8), respectively. The scores after 8 weeks were 9.7(4.1) and 15.1(7.8), respectively. Repeated measures of ANOVA showed that there was a significant difference between the two groups after 8 weeks. The most common adverse effects in the NAC+risperidone group were constipation (16.1%), increased appetite (16.1%), fatigue (12.9%), nervousness (12.9%), and daytime drowsiness (12.9%). There was no fatal adverse effect.

Conclusions

Risperidone plus NAC more than risperidone plus placebo decreased irritability in children and adolescents with ASD. Meanwhile, it did not change the core symptoms of autism. Adverse effects were not common and NAC was generally tolerated well.

A randomized double blind placebo controlled clinical trial of N-Acetylcysteine added to risperidone for treating autistic disorders

N-ацетилцистеин в коррекции возбудимости у детей с аутизмом

Background
An imbalance in the excitatory/inhibitory systems with abnormalities in the glutamatergic pathways has been implicated in the pathophysiology of autism. Furthermore, chronic redox imbalance was also recently linked to this disorder. The goal of this pilot study was to assess the feasibility of using oral N-acetylcysteine (NAC), a glutamatergic modulator and an antioxidant, in the treatment of behavioral disturbance in children with autism.
Methods
This was a 12-week, double-blind, randomized, placebo-controlled study of NAC in children with autistic disorder. Subjects randomized to NAC were initiated at 900 mg daily for 4 weeks, then 900 mg twice daily for 4 weeks and 900 mg three times daily for 4 weeks. The primary behavioral measure (Aberrant Behavior Checklist [ABC] irritability subscale) and safety measures were performed at baseline and 4, 8, and 12 weeks. Secondary measures included the ABC stereotypy subscale, Repetitive Behavior Scale-Revised, and Social Responsiveness Scale.
Results
Thirty-three subjects (31 male subjects, 2 female subjects; aged 3.2–10.7 years) were randomized in the study. Follow-up data was available on 14 subjects in the NAC group and 15 in the placebo group. Oral NAC was well tolerated with limited side effects. Compared with placebo, NAC resulted in significant improvements on ABC irritability subscale (F = 6.80; p < .001; d = .96).
Conclusions
Data from this pilot investigation support the potential usefulness of NAC for treating irritability in children with autistic disorder. Large randomized controlled investigations are warranted.

 A Randomized Controlled Pilot Trial of Oral N-Acetylcysteine in Children with Autism

Добавление N-ацетилцистеина может облегчать симптоматику депрессии при БАР

In an open-label study from Australian researchers presented here at the Ninth International Conference on Bipolar Disorder (ICBD), patients diagnosed with bipolar disorder and given 2000 mg of NAC in addition to their "treatment as usual" showed significantly lower symptom severity scores and increased functioning and quality-of-life scores.

Adjunctive N-Acetyl Cysteine Effective for Bipolar Depression

Перспективы лечения БАР

Excitotoxicity
Several lines of evidence suggest that glutamatergic system dysfunction (eg, N-methyl d-aspartate [NMDA] receptor complex) may play a critical role in the pathophysiology of bipolar disorder. In keeping with this view, the use of glutamatergic modulators may be predicted to alleviate symptoms and modify the disease process. Postmortem studies indicate that altered NMDA receptor complexes are observed in the brain tissue of patients with bipolar disorder. Moreover, genetic polymorphisms for genes implicated in the glutamate receptor complex have been associated with this disorder.6
Riluzole, an inhibitor of glutamate release, is approved by the FDA for the treatment of amyotrophic lateral sclerosis. This agent, at a dosage of 50 to 200 mg/d, was evaluated in an 8-week add-on study in combination with lithium in 14 adults with bipolar depression, 6 of whom had bipolar I disorder, and 8 of whom had bipolar II disorder. Eight patients completed the 8-week trial.6 Significant improvement in depressive symptoms was noted in weeks 5 through 8 as measured by the Montgomery Asberg Depression Rating Scale (MADRS).
Ketamine is a noncompetitive NMDA antagonist that has been evaluated in subanesthetic doses in persons with bipolar disorder.7 Results from a double-blind, randomized, placebo-controlled, crossover study indicate that a single intravenous infusion of ketamine(Drug information on ketamine) combined with lithium or valproate(Drug information on valproate) was capable of alleviating depressive symptoms within 40 minutes of administration when compared with placebo.7 The benefit of ketamine was sustained through day 3. Overall, 71% of patients responded to ketamine and 6% responded to placebo at some point during the trial. Ketamine was not associated with significant increases in hypomania or mania but was associated with dissociative symptoms.

Cyclooxygenase-2 (COX-2) inhibitors have been shown to protect against glutamate-induced neurotoxicity; to prevent normal aging-related increases of cytokines, prostaglandins, and TNF in neurons; and to modulate the hypothalamic adrenal axis.10 The COX-2 inhibitor celecoxib(Drug information on celecoxib) was evaluated as a potential antidepressant in adults with bipolar I/II depression (N = 28).10 This drug was administered at a dosage of 400 mg daily in combination with a mood stabilizer or antipsychotic medication as part of a 6-week, randomized, double-blind, placebo-controlled study. Depressive symptoms in both the treatment group and the placebo group improved, with a statistically significant (P = .01) advantage at week 1 in patients treated with celecoxib compared with patients who received placebo. Although there was an advantage in favor of the treatment group at week 1, both the active-treatment and placebo groups had similar reductions for each of the remaining observation points.

Several case reports and case series suggest that insulin sensitizers (eg, rosiglitazone(Drug information on rosiglitazone)) may offer an antidepressant effect in persons with major depressive disorder. Studies are currently under way in bipolar disorder. For example, several studies are evaluating the antidepressant effects of intranasal insulin and insulin secretagogues (eg, incretins) in bipolar disorder. Moreover, there is ongoing research to determine whether weight loss, bariatric surgery, and dietary modification (eg, ketogenic diet) improve depressive symptoms in persons with bipolar disorder.

Results from a randomized, double-blind, multicenter, placebo-controlled study of adults with bipolar disorder (N = 75) indicate that N-acetylcysteine (1 g bid) adjunctive to usual medications was capable of alleviating depressive symptoms as measured by the MADRS.14 The benefit on depressive symptoms was noted at week 20 as part of this 24-week study. Benefits were noted by week 8 on the Global Assessment of Functioning Scale and Social and Occupational Functioning Assessment Scale. N-acetylcysteine did not induce hypomania or mania and was well tolerated. Adverse events reported in more than 15% of the N-acetylcysteine group included change in energy, headaches, heartburn, and increased joint pain.

Armodafinil is the longer-lasting isomer of modafinil, and its therapeutic indications are similar to those of the racemic agent modafinil. Armodafinil at a dosage of 150 mg/d was evaluated as an antidepressant in adults with bipolar disorder who received either olanzapine, lithium, or valproic acid as part of an 8-week double-blind placebo-controlled study.

Novel Treatment Avenues for Bipolar Depression

Глутаматергические лекарственные средства для лечения шизофрении

Glutamatergic drugs in development

Target	Proposed mechanism	Proposed agents	Phase of development
Glycine/D-serine receptor	Allosteric modulator of the NMDA receptor	Glycine, D-serine, D-alanine, D-cycloserine	Phase II
Glycine-type I transport inhibitor	Blocks the reuptake of glycine, akin to SSRIs’ action on serotonin	Sarcosine, RG1678	Phase II/III
Metabotropic glutamate type 2/3 (mGluR2/3)	Blocks presynaptic glutamate release	LY-2140023	Phase II
Redox sensitive site	Allosteric modulator of the NMDA receptor	N-acetylcysteine	Phase II
D-amino acid oxidase (DAAO) inhibitors	Inhibits the enzyme that metabolizes D-serine	Remains in preclinical stage
Tetrahydrobiopterin (BH4)	Indirectly modulates glutamatergic system	Remains in preclinical stage
NMDA: N-methyl-D-aspartate; SSRIs: selective serotonin reuptake inhibitors

Glycine/D-serine site agonists. To date, most studies have used glutamatergic drugs adjunctive to antipsychotics and targeted the glycine/D-serine modulatory site, in part because glycine and D-serine are natural compounds and therefore FDA approval for their use could be obtained without the extensive preclinical development usually required for new chemical entities.¹⁶ Unfortunately, these agents are less potent than traditional pharmaceuticals, and delivering optimal doses may be impossible. Nevertheless, positive studies with these compounds have provided proof-of-concept for development of agents with higher affinity and specificity.

Studies have used glycine administered at doses up to 60 g/d, D-serine up to 8 g/d, or D-alanine approximately 6 g/d. For glycine, 60 g/d is the highest dose that can be given because of concerns about tolerability and replacement of other essential amino acids. D-serine originally was tested at approximately 2 g/d with promising results, but a recent open-label trial suggested that higher doses may be more efficacious.¹⁷ D-serine doses are limited by potential renal toxicity, as demonstrated in rodents studies.

Although not all studies of glycine/D-serine site agonists have been positive, a recent meta-analysis suggests significant improvement in negative symptoms across studies.¹⁸ Variability in statistical results across studies is related primarily to degree of placebo effect within individual trials, with a mean improvement in negative symptoms of approximately 15%. Glycine/D-serine site agonists seem to be less effective when combined with clozapine, possibly because clozapine may already enhance the glutamatergic system and increase synaptic glycine levels.⁶

One study that evaluated effects of open-label glycine in individuals with schizophrenia symptoms observed a large effect-size improvement, including early remission in 3 of 10 patients.¹⁹ These data—if confirmed by double-blind trials—would indicate that glycine/d-serine site agonists might have utility in treating the schizophrenia prodrome.

Glycine transport inhibitors. A potential indirect approach to raising glycine levels in the brain is using GlyT1-type glycine transport inhibitors (GTIs). GlyT1 transporters are co-localized in brain with NMDARs and modulate local glycine levels. Rather than binding directly to the NMDAR glycine binding site, GTIs increase glycine levels in the synapse by preventing its removal by GlyT1 transporters. Their function is analogous to using selective serotonin reuptake inhibitors to increase serotonin levels in patients with depression.⁶

Sarcosine (N-methylglycine) is a naturally occurring GlyT1 inhibitor that has been used in early clinical trials in Taiwan. Initial studies with sarcosine showed efficacy similar to—and in some cases better than—that of direct glycine/D-serine site agonists when added to first-generation or non-clozapine second-generation antipsychotics.¹⁸ Sarcosine also has been found to be effective for acute treatment of schizophrenia.²⁰ At present, however, sarcosine is not available for experimental use in the United States because of toxicity considerations.

Using high-affinity GTIs for schizophrenia was first proposed in the mid-1990s,⁶ but such compounds are only now entering clinical efficacy studies. Most recently, phase II results were presented for RG1678, a compound developed by Hoffman LaRoche.²¹ The study targeted persistent negative symptoms in patients receiving chronic antipsychotic treatment. Adding RG1678, 10 mg and 30 mg, to antipsychotics led to significant improvement in persistent negative symptoms vs placebo. These promising results are being followed up in phase III studies.

Other glutamatergic options. Few compounds are available to modulate NMDARs at sites other than the glycine/D-serine site. One study administered N-acetylcysteine, a glutathione precursor, as a potential treatment for persistent negative symptoms.²² Encouraging clinical results were observed in this double-blind study, along with improvement in electrophysiologic measures, negative symptoms, and overall functioning, but the study was limited by relatively high rates of noncompletion. Preclinical studies have combined D-serine with an inhibitor of D-amino acid oxidase to prevent D-serine breakdown.²³ In rodents, this approach produces a 30-fold increase in D-serine potency.

Tetrahydrobiopterin (BH₄) is a cofactor for enzymes responsible for the synthesis of dopamine and other monoamines, and presynaptic release of dopamine and glutamate. Reductions in BH₄ levels have been reported in schizophrenia, which suggests that this compound may be etiologically important.²⁴ Researchers have initiated a study of this compound in schizophrenia.

Other schizophrenia models propose that the crucial issue is not NMDA blockade but subsequent dysregulation of presynaptic glutamate release. Type 2/3 metabotropic glutamate receptors (mGluR2/3) are located on presynaptic glutamate terminals and inhibit presynaptic glutamate release. mGluR2/3 agonists have been shown to reverse ketamine’s effects in humans and in animal models,^25,26 which suggests a potential role in schizophrenia treatment.

The first mGluR2/3 agonist entered into monotherapy clinical efficacy trials for schizophrenia was LY-2140023. In an initial trial, this compound showed significant efficacy in improving positive and negative symptoms, comparable to that of olanzapine.²⁷ However, a follow-up study failed because of a large placebo effect,²⁸ which leaves the efficacy question unresolved.In contrast to mGluR2/3, type 5 metabotropic receptors (mGluR5) are co-localized with NMDA receptors and potentiate activation. Thus, mGluR5 agonists also may be effective for treating schizophrenia. These compounds remain in preclinical development. Other approaches, such as stimulating specific types of GABA receptors to overcome glutamatergic deficits, remain promising but have not been tested in definitive clinical trials.
Glutamate: New hope for schizophrenia treatment

Ацетилцистеин в психиатрической практике

Through its metabolic contribution to glutathione production, cysteine participates in the general antioxidant activities of the body. Through its role as a modulator of the glutamatergic system, cysteine influences the reward-reinforcement pathway. Because of these functions, NAC may exert a therapeutic effect on psychiatric disorders allegedly related to oxidative stress (e.g., schizophrenia, bipolar disorder) as well as psychiatric syndromes characterized by impulsive/compulsive symptoms (e.g., trichotillomania, pathological nail biting, gambling, substance misuse). While the dosages, pharmacological strategies (monotherapy versus augmentation), and long-term risks are not fully evident, NAC appears to be a promising, relatively low-risk intervention.

Getting a Knack for NAC

Глутаматергические механизмы ОКР

Glutamatergic Dysfunction in Obsessive-Compulsive Disorder and the Potential Clinical Utility of Glutamate-Modulating Agents

ацетилцистеин и трихотилломания

Группе из 50 человек, страдающих трихотилломанией, предложили принять участие в 12-недельном исследовании, в котором половине из них давали таблетки, содержащие аминокислоту N-ацетилцистеин, а остальным — плацебо. Оказалось, спустя 12 недель, что среди людей, принимавших аминокислоты, значительно ослабла мания выдергивать у себя волосы, по сравнению с контрольной группой, сообщили специалисты.

Прием ацетилцистеина может уменьшать симптомы трихотилломании