CREB: A Promising Therapeutic Target for Treating Psychiatric Disorders

Psychiatric disorders are complex, multifactorial illnesses. It is challenging for us to understand the underlying mechanism of psychiatric disorders. In recent years, the morbidity of psychiatric disorders has increased yearly, causing huge economic losses to the society. Although some progress, such as psychotherapy drugs and electroconvulsive therapy, has been made in the treatment of psychiatric disorders, including depression, anxiety, bipolar disorder, obsessive-compulsive and autism spectrum disorders, antidepressants and psychotropic drugs have the characteristics of negative effects and high rate of relapse. Therefore, researchers continue to seek suitable interventions. cAMP response element binding protein (CREB) belongs to a protein family and is widely distributed in the majority of brain cells that function as a transcription factor. It has been demonstrated that CREB plays an important role in neurogenesis, synaptic plasticity, and neuronal growth. This review provides a 10-year update of the 2013 systematic review on the multidimensional roles of CREB-mediated transcriptional signaling in psychiatric disorders. We also summarize the classification of psychiatric disorders and elucidate the involvement of CREB and related downstream signalling pathways in psychiatric disorders. Importantly, we analyse the CREB-related signal pathways involving antidepressants and antipsychotics to relieve the pathological process of psychiatric disorders. This review emphasizes that CREB signalling may have a vast potential to treat psychiatric disorders like depression. Furthermore, it would be helpful for the development of potential medicine to make up for the imperfection of current antidepressants and antipsychotics.

New Insight in Improving Therapeutic Efficacy of Antipsychotic Agents: An Overview of Improved In Vitro and In Vivo Performance, Efficacy Upgradation and Future Prospects

Psychotic disorders are recognized as severe mental disorders that rigorously affect patient's personality, critical thinking, and perceptional ability. High prevalence, global dissemination and limitations of conventional pharmacological approaches compel a significant burden to the patient, medical professionals and the healthcare system. To date, numerous orally administered therapies are available for the management of depressive disorders, schizophrenia, anxiety, bipolar disorders and autism spectrum problems. However, poor water solubility, erratic oral absorption, extensive first-pass metabolism, low oral bioavailability and short half-lives are the major factors which limit the pharmaceutical significance and therapeutic feasibility of these agents. In recent decades, nanotechnology-based delivery systems have gained remarkable attention of the researchers to mitigate the pharmaceutical issues related to the antipsychotic therapies and to optimize their oral drug delivery, therapeutic outcomes, and patient compliance. Therefore, the present review was aimed to summarize the available in vitro and in vivo evidences signifying the pharmaceutical importance of the advanced delivery systems in improving the aqueous solubility, transmembrane permeability, oral bioavailability and therapeutic outcome of the antipsychotic agents.

Relevance of CYP2C9 Function in Valproate Therapy

BACKGROUND

Genetic polymorphisms of drug metabolizing enzymes can substantially modify the pharmacokinetics of a drug and eventually its efficacy or toxicity; however, inferring a patient's drug metabolizing capacity merely from his or her genotype can lead to false prediction. Non-genetic host factors (age, sex, disease states) and environmental factors (nutrition, comedication) can transiently alter the enzyme expression and activities resulting in genotypephenotype mismatch. Although valproic acid is a well-tolerated anticonvulsant, pediatric patients are particularly vulnerable to valproate injury that can be partly attributed to the age-related differences in metabolic pathways.

METHODS

CYP2C9 mediated oxidation of valproate, which is the minor metabolic pathway in adults, appears to become the principal route in children. Genetic and non-genetic variations in CYP2C9 activity can result in significant inter- and intra-individual differences in valproate pharmacokinetics and valproate induced adverse reactions.

RESULTS

The loss-of-function alleles, CYP2C9*2 or CYP2C9*3, display significant reduction in valproate metabolism in children; furthermore, low CYP2C9 expression in patients with CYP2C9*1/*1 genotype also leads to a decrease in valproate metabolizing capacity. Due to phenoconversion, the homozygous wild genotype, expected to be translated to CYP2C9 enzyme with normal activity, is transiently switched into poor (or extensive) metabolizer phenotype.

CONCLUSION

Novel strategy for valproate therapy adjusted to CYP2C9-status (CYP2C9 genotype and CYP2C9 expression) is strongly recommended in childhood. The early knowledge of pediatric patients' CYP2C9-status facilitates the optimization of valproate dosing which contributes to the avoidance of misdosing induced adverse reactions, such as abnormal blood levels of ammonia and alkaline phosphatase, and improves the safety of children's anticonvulsant therapy.

Review of the use of Topiramate for treatment of psychiatric disorders

BACKGROUND: Topiramate is a new antiepileptic drug, originally designed as an oral hypoglycaemic subsequently approved as anticonvulsant. It has increasingly been used in the treatment of numerous psychiatric conditions and it has also been associated with weight loss potentially relevant in reversing weight gain induced by psychotropic medications. This article reviews pharmacokinetic and pharmacodynamic profile of topiramate, its biological putative role in treating psychiatric disorders and its relevance in clinical practice. METHODS: A comprehensive search from a range of databases was conducted and papers addressing the topic were selected. RESULTS: Thirty-two published reports met criteria for inclusion, 4 controlled and 28 uncontrolled studies. Five unpublished controlled studies were also identified in the treatment of acute mania. CONCLUSIONS: Topiramate lacks efficacy in the treatment of acute mania. Increasing evidence, based on controlled studies, supports the use of topiramate in binge eating disorders, bulimia nervosa, alcohol dependence and possibly in bipolar disorders in depressive phase. In the treatment of rapid cycling bipolar disorders, as adjunctive treatment in refractory bipolar disorder in adults and children, schizophrenia, posttraumatic stress disorder, unipolar depression, emotionally unstable personality disorder and Gilles de la Tourette's syndrome the evidence is entirely based on open label studies, case reports and case series. Regarding weight loss, findings are encouraging and have potential implications in reversing increased body weight, normalisation of glycemic control and blood pressure. Topiramate was generally well tolerated and serious adverse events were rare.