Current Pharmaceutical Design - Volume 26, Issue 2, 2020

Schizophrenia and bipolar disorder overlap considerably in terms of symptoms, familial patterns, risk genes, outcome, and treatment response. This article provides an overview of the specificity and continuity of schizophrenia and mood disorders on the basis of biomarkers, such as genes, molecules, cells, circuits, physiology and clinical phenomenology. Overall, the discussions herein provided support for the view that schizophrenia, schizoaffective disorder and bipolar disorder are in the continuum of severity of impairment, with bipolar disorder closer to normality and schizophrenia at the most severe end. This approach is based on the concept that examining biomarkers in several modalities across these diseases from the dimensional perspective would be meaningful. These considerations are expected to help develop new treatments for unmet needs, such as cognitive dysfunction, in psychiatric conditions.

Functional near-infrared spectroscopy (fNIRS) is a recently developed technique that can measure hemoglobin changes in the cerebral cortex, and fNIRS-based research in psychiatry has been progressing rapidly. fNIRS is advantageous in its noninvasiveness, ease of administration, tolerance of small movements, inexpensiveness, strong signal correlations with fMRI signals, and in providing imaging with excellent time resolution and moderate spatial resolution. However, fNIRS has several disadvantages, such as low spatial resolution and shallower measurements in brain regions compared with other functional neuroimaging techniques (e.g. functional magnetic resonance imaging and positron emission tomography). Therefore, fNIRS may be a candidate instrument for clinical use in psychiatry, as it can measure brain activity in a clinical setting. Moreover, previous studies have demonstrated that altered brain activity in the prefrontal cortex is associated with clinical symptoms and functional outcomes in patients with schizophrenia, suggesting that fNIRS could be used as a potential biomarker. Future studies aimed at exploring fNIRS differences in different clinical stages, longitudinal changes, medication effects, variations during different cognitive task paradigms, cross-cultural comparisons, and applying more delicate statistical analytic methodologies are warranted to develop more accurate biomarkers that can be applied in clinical practice for differential diagnosis, monitoring symptoms, predicting functional outcomes, and the personalized decision regarding treatment options in patients with schizophrenia.

Background: Clozapine has been used in treatment-resistant patients with schizophrenia. However, only 40% of patients with treatment-resistant schizophrenia have response to clozapine. Many augmentation strategies have been proposed to treat those clozapine-resistant patients, but the results are inconclusive. In this review, we intended to review papers dealing with the augmentation strategies in the treatment of clozapineresistant patients with schizophrenia. Method: We reviewed randomized, double-blind, placebo- or sham-controlled trials (RCT) for clozapine-resistant patients with schizophrenia in Embase, PsycINFO, Cochrane, and PubMed database from January 1990 to June 2019. Results: Antipsychotics, antidepressants, mood stabilizers, brain stimulation, such as electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation, and other strategies, were used as an augmentation in clozapine-resistant patients with schizophrenia. Except for better evidence in memantine with 2 RCTs and cognitive behavior therapy in 2 studies to support its effectiveness, we found that all the other effective augmentations, including sulpiride, ziprasidone, duloxetine, mirtazapine, ECT, sodium benzoate, ginkgo biloba, and minocycline, had only one RCT with limited sample size. Conclusion: In this review, no definite effective augmentation strategy was found for clozapine-resistant patients. Some potential strategies with beneficial effects on psychopathology need further studies with a larger sample size to support their efficacy.

Major depressive disorder (MDD) is an important cause of disability in the world. Depression has negative influences on a person’s mental and physical health, quality of life, and functioning. The pathophysiology of depression has not yet been confirmed. The traditional monoamine hypothesis of MDD could not explain the unsatisfactory treatment response of antidepressants. Thus, it is necessary to search other probable pathophysiology of MDD. In recent years, the role of glutamate neurotransmission in depression has drawn much attention. The N-methyl-D-aspartate receptor (NMDAR) is a subclass of glutamate receptors and is implicated in the pathogenesis of MDD and other mental disorders. Furthermore, NMDAR ligands, such as ketamine and Dcycloserine, have shown antidepressive effects in several studies. The diagnosis of MDD depends on physician’s subjective evaluation which is often inconsistent. Therefore, reliable objective laboratory biomarkers are essential for more accurate and consistent diagnosis of MDD. In this review, we firstly described the structure and regulation of the NMDAR. We then searched different genes involved in the pathway of glutamatergic neurotransmission and NMDAR, including D-amino acids, glycine, and glutamate. Various related enzymes and transporters that play a role in the modulation of NMDAR neurotransmission were also surveyed. This review aims to investigate NMDAR related metabolism, which may serve as feasible indicators for MDD and may contribute to further exploration of reliable biomarkers for MDD and promote new treatment of depression.

Background: The nervous system and the immune system interact consistently in the brain and peripheries. Inflammation in the brain not only alters the metabolism of neurotransmitters, but also causes network dysfunction, structural changes, and the development of mood symptomology in patients with mood disorders. In addition, the dysregulation of the neuroimmune axis in mood disorders drives multiple-system comorbidities. Furthermore, patients with low-grade inflammation are more likely to exhibit treatment resistance with both pharmacotherapy and non-pharmacotherapy. Objective: The aim of this review was to examine the available data regarding not only evidence of inflammation in the pathophysiology of mood disorders and their comorbid conditions, but also potential inflammatory biomarkers of mood disorders. Methods: Studies of the use of adjunct anti-inflammatory medications in mood disorders, and inflammatory biomarkers that may guide treatment outcomes in mood disorders, were summarized. Results: Studies have demonstrated that certain adjunct anti-inflammatory medications might help to improve mood symptoms and reduce comorbidities, and the baseline levels of inflammatory biomarkers, such as peripheral C-reactive protein (CRP), could be used to stratify the treatment outcome. All results suggested that the identification of peripheral and brain inflammatory biomarkers for the diagnosis, outcome prediction, staging, and stratification of interventions of mood disorders has emerged as an important area of translational research in psychiatry. Conclusion: Inflammatory biomarkers could guide interventions and enhance treatment response in patients with mood disorders. The main challenge is that substantial complexities might hamper the attainment of this goal.

In this narrative review, we intended to summarize the evidence of pharmacological and somatic treatment choices for treatment-resistant depression (TRD). There are several types of therapeutic strategies to improve inadequate response to antidepressant treatment. The first step for patients with TRD is to optimize the dosage and duration of antidepressants as well as to ensure their drug compliance. The shift to antidepressant and antidepressant combination therapy for patients with TRD cannot be regarded as an evidence-based strategy. Only the combination of a monoamine reuptake inhibitor with a presynaptic α2-autoreceptor antagonist might have better efficacy than other antidepressant combinations. Currently, the most evidence-based treatment options for TRD are augmentation strategies. Among augmentative agents, second-generation antipsychotics and lithium have the strongest evidence for the management of TRD. Further studies are needed to evaluate the augmentative efficacy of anticonvulsants, thyroid hormone, glutamatergic agents, anti-inflammatory agents, and nutraceuticals for TRD. Among somatic therapies, electroconvulsive therapy and repetitive transcranial magnetic stimulation are effective for TRD. Further studies are warranted to provide clinicians with a better recommendation in making treatment choices in patients with TRD.

Background: Cell-cell adhesion is essential in maintaining the structure and function of an organ. Several adhesion molecules have recently been identified as associated with heroin dependence in both genetic and peripheral plasma studies. Methods and Results: We reviewed literature concerning studies on adhesion molecules in opioid addictions in rodents and human, including human genetic associations in different ethnic groups, and treatment responses to methadone maintenance treatment in heroin-dependent patients. Conclusion: Some important and novel findings were summarized and discussed. Adhesion molecules in the peripheral plasma, e.g., cadherin-2 (CDH2), may be biomarkers for both methadone treatment outcome and nectin 4 may be an indicator for continued opioid use. Neural cell adhesion molecule (NCAM) in the central nervous system may regulate opioid withdrawal and analgesic responses. Future studies to uncover the mechanisms underlying the involvement of adhesion molecules in the pathological process of addictions will be an important research direction in the field.

Background: Methamphetamine (METH) is one of the most widely distributed psychostimulants worldwide. Despite active counter measures taken by different countries, neither overall usage of METH nor the frequency of repeat users has reduced over the past decade. METH induces abuse and dependence as it acts on the central nervous system and temporarily stimulates the brain. The recidivism rate for abuse of stimulants in Japan is very high and therefore prevention of repeated usage is paramount. However, we lack information about the relationship between METH users and genomic changes in humans in Japan, which would provide important information to aid such efforts. Objective: Shati/Nat8l is a METH-inducible molecule and its overexpression has protective effects on the brain upon METH usage. Here we investigated the effect of METH usage on DNA methylation rates at the promoter site of SHATI/NAT8L. We used DNA samples from human METH users, who are usually difficult to recruit in Japan. Methods: We measured DNA methylation at SHATI/NAT8L promoter sites by pyrosequencing method using 193 samples of METH users and 60 samples of healthy subjects. In this method, DNA methylation is measured by utilizing the property that only non-methylated cytosine changes to urasil after bisulfite conversion. Results: We found that the rate of DNA methylation at six CpG islands of SHATI/NAT8L promoter sites is significantly higher in METH users when compared to healthy subjects. Conclusion: These results suggest that the DNA methylation rate of SHATI/NAT8L promotor regions offers a new diagnostic method for METH usage.

The role of angiogeneses during the growth and progression of tumors is well documented. Likewise, a balance is generally maintained between the cellular proliferation and the apoptosis, therefore, the tumors can persist for years in a dormant phase. During the past few years, many hypotheses have been proposed relating to the importance of tumor angiogenesis for the development and spread of tumors and preventive or therapeutic capacity of angiogenesis inhibitors as a potential target for controlling the growth of cancerous tissue. The antiangiogenic based therapeutic approaches are considered as the most promising method for the control of tumors, as this therapeutic approach is less likely to attain the drug resistance. Further, the tumor vasculature is an important prognostic marker that can independently predict the pathological stages as well as the metastatic potential of tumors. Various biologically active phytochemicals have been extracted from the dietary sources and the plants that have engaged the scientist and pharmaceutical industries around the globe. The antioxidant, antiinflammatory, anti-proliferative and anti-angiogenic potential of these bioactive phytochemicals is evident from the in vitro studies using cell lines and investigations involving the animal models. The present review is focused on the promising role of anti-angiogenesis-based therapies for the management of tumors and the recent developments relating to the interplay of phytochemicals and angiogenesis for the suppression of tumor cells.

Recently, the delivery of hydrophobic/ poorly water-soluble drugs has been a challenging task. Various strategies have been developed to counter the former along with other prime issues, such as stability, bioavailability etc. However, only few formulations have been successful in addressing the problems and nanoemulgel is a standout among them. Nanoemulgels are appropriate candidates for drug delivery because of their dual character i.e. the presence of an emulsion in the nano scale and a gel base, both combined as a single formulation. The nanoemulsion component of the nanoemulgel conforms protection to the active moiety by preventing the enzymatic degradation and certain reactions like hydrolysis. The gel base attributes thermodynamic stability to the emulsion by increasing the viscosity of the aqueous phase by decreasing the interfacial and surface tension. Nanoemulgels possess rheological characteristics which are suited especially for topical delivery and other forms such as dental delivery with the aid of better patient acceptance. As the globule size is present in the nano form alongside the employment of certain penetration enhancers can increase the effectiveness of the formulation by enhancing the permeability and diffusibility. Reports suggest that certain commercially available topical dosage forms have a low spreading coefficient in comparison with the nanoemulgel thereby focusing on the application of nanoemulgels in the field of dermatology, although paving way for various other fields have not been thoroughly exploited. This comprehensive review highlights the benefits of nanoemulgel as a potential carrier for drug delivery with an overview of few illustrations supporting the cause.