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1.
Phosphodiesterase as a Target for Cognition Enhancement in Schizophrenia.
Al-Nema, MY, Gaurav, A
Current topics in medicinal chemistry. 2020;(26):2404-2421
Abstract
Schizophrenia is a severe mental disorder that affects more than 1% of the population worldwide. Dopamine system dysfunction and alterations in glutamatergic neurotransmission are strongly implicated in the aetiology of schizophrenia. To date, antipsychotic drugs are the only available treatment for the symptoms of schizophrenia. These medications, which act as D2-receptor antagonist, adequately address the positive symptoms of the disease, but they fail to improve the negative symptoms and cognitive impairment. In schizophrenia, cognitive impairment is a core feature of the disorder. Therefore, the treatment of cognitive impairment and the other symptoms related to schizophrenia remains a significant unmet medical need. Currently, phosphodiesterases (PDEs) are considered the best drug target for the treatment of schizophrenia since many PDE subfamilies are abundant in the brain regions that are relevant to cognition. Thus, this review aims to illustrate the mechanism of PDEs in treating the symptoms of schizophrenia and summarises the encouraging results of PDE inhibitors as anti-schizophrenic drugs in preclinical and clinical studies.
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2.
Novel Treatment for the Most Resistant Schizophrenia: Dual Activation of NMDA Receptor and Antioxidant.
Lin, CH, Chen, YM, Lane, HY
Current drug targets. 2020;(6):610-615
Abstract
Clozapine has been regarded as the last-line antipsychotic agent for patients with refractory schizophrenia. However, many patients remain unresponsive to clozapine, referred to as "clozapineresistant", "ultra-treatment-resistant", or remain in incurable state. There has been no convincing evidence for augmentation on clozapine so far. Novel treatments including numerous N-methyl-Daspartate (NMDA) receptor (NMDAR) enhancers, such as glycine, D-serine, D-cycloserine, and Nmethylglycine (sarcosine) failed in clinical trials. Earlier, the inhibition of D-amino acid oxidase (DAAO) that may metabolize D-amino acids and activate NMDAR has been reported to be beneficial for patients with schizophrenia receiving antipsychotics except for clozapine. A recent randomized, double-blind, placebo-controlled clinical trial found that add-on sodium benzoate, a DAAO inhibitor, improved the clinical symptoms in patients with clozapine- resistant schizophrenia, possibly through DAAO inhibition (and thereby NMDAR activation) and antioxidation as well; additionally, sodium benzoate showed no obvious side effects, indicating that the treatment is safe at doses up to 2 g per day for 6 weeks. More studies are warranted to elucidate the mechanisms of sodium benzoate for the treatment of schizophrenia and the etiology of this severe brain disease. If the finding can be reconfirmed, this approach may bring new hope for the treatment of the most refractory schizophrenia. This review summarizes the current status of clinical trials and related mechanisms for treatmentresistant, especially, clozapine-resistant schizophrenia. The importance of understanding the molecular circuit switches is also highlighted which can restore brain function in patients with schizophrenia. Future directions in developing better treatments for the most difficult to cure schizophrenia are also discussed.
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3.
Nonmedical Interventions for Schizophrenia: A Review of Diet, Exercise, and Social Roles.
Helman, DS
Holistic nursing practice. 2020;(2):73-82
Abstract
Schizophrenia is a major mental illness with a disease course that is influenced by lifestyle. The risk-benefit ratio for alternative interventions is more favorable than for antipsychotics in long-term treatment. Dietary interventions may target autoimmune features, vitamin or mineral deficiencies, abnormal lipid metabolism, gluten sensitivity, or others. Examples of interventions involving diet, physical activity, or physical processes or social interventions including talk therapy exist in the literature. Notwithstanding, the general utility of these types of interventions remains inconclusive, awaiting long-term randomized trials. A perspective that separates the cause of the disease from its symptoms may be helpful in treatment planning and is warranted to distinguish between short-term and long-term recovery goals.
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4.
Therapeutic Potential of Carnosine and Its Derivatives in the Treatment of Human Diseases.
Chmielewska, K, Dzierzbicka, K, Inkielewicz-Stępniak, I, Przybyłowska, M
Chemical research in toxicology. 2020;(7):1561-1578
Abstract
Despite significant progress in the pathogenesis, diagnosis, treatment, and prevention of cancer and neurodegenerative diseases, their occurrence and mortality are still high around the world. The resistance of cancer cells to the drugs remains a significant problem in oncology today, while in the case of neuro-degenerative diseases, therapies reversing the process are still yet to be found. Furthermore, it is important to seek new chemotherapeutics reversing side effects of currently used drugs or helping them perform their function to inhibit progression of the disease. Carnosine, a dipeptide constisting of β-alanine and l-histidine, has a variety of functions to mention: antioxidant, antiglycation, and reducing the toxicity of metal ions. It has therefore been proposed to act as a therapeutic agent for many pathological states. The aim of this paper was to find if carnosine and its derivatives can be helpful in treating various diseases. Literature search presented in this review includes review and original papers found in SciFinder, PubMed, and Google Scholar. Searches were based on substantial keywords concerning therapeutic usage of carnosine and its derivatives in several diseases including neurodegenerative disorders and cancer. In this paper, we review articles and find that carnosine and its derivatives are potential therapeutic agents in many diseases including cancer, neurodegenerative diseases, diabetes, and schizophrenia. Carnosine and its derivatives can be used in treating neurodegenerative diseases, cancer, diabetes, or schizophrenia, although their usage is limited. Therefore, there's an urge to synthesize and analyze new substances, overcoming the limitation of carnosine itself.
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The phenolic interactome and gut microbiota: opportunities and challenges in developing applications for schizophrenia and autism.
Jaskiw, GE, Obrenovich, ME, Donskey, CJ
Psychopharmacology. 2019;(5):1471-1489
Abstract
Schizophrenia and autism spectrum disorder have long been associated with elevated levels of various small phenolic molecules (SPMs). In turn, the gut microbiota (GMB) has been implicated in the kinetics of many of these analytes. Unfortunately, research into the possible relevance of GMB-mediated SPMs to neuropsychiatry continues to be limited by heterogeneous study design, numerous sources of variance and technical challenges. Some SPMs have multiple structural isomers and most have conjugates. Without specialized approaches, SPMs can be incorrectly assigned or inaccurately quantified. In addition, SPM levels can be affected by dietary polyphenol or protein consumption and by various medications and diseases. Nonetheless, heterotypical excretion of various SPMs in association with schizophrenia or autism continues to be reported in independent samples. Recent studies in human cerebrospinal fluid demonstrate the presence of many SPMs A large number of these are bioactive in experimental models. Whether such mechanisms are relevant to the human brain in health or disease is not known. Systematic metabolomic and microbiome studies of well-characterized populations, an appreciation of multiple confounds, and implementation of standardized approaches across platforms and sites are needed to delineate the potential utility of the phenolic interactome in neuropsychiatry.
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6.
Keeping up with the therapeutic advances in schizophrenia: a review of novel and emerging pharmacological entities.
Krogmann, A, Peters, L, von Hardenberg, L, Bödeker, K, Nöhles, VB, Correll, CU
CNS spectrums. 2019;(S1):38-69
Abstract
Schizophrenia remains one of the most severe medical diseases. Current dopamine modulating first-generation and second-generation antipsychotics target mainly positive symptoms, but not/inadequately negative and cognitive symptoms. Additional challenges include non-adherence and adverse effects, especially cardiometabolic dysregulation. This review evaluates new/emerging pharmacological treatments for schizophrenia. Therapies targeting total symptoms include cannabidiol, D3 antagonist/5-HT1A partial agonist F17464, lumateperone (ITI-007), phosphodiesterase 10A (PDE10A) inhibitors MK-8189 and TAK-063, sodium nitroprusside, and trace amine-associated receptor-1 (TAAR1) agonist RO5263397 and SEP-363856. Treatments targeting negative symptoms include the PDE10A inhibitor LuAF-11167, 5-HT2A inverse agonist pimavanserin, sigma-2/5-HT2A antagonist roluperidone (MIN-101), and d-amino acid oxidase (DAAO) inhibitor TAK-831. Agents targeting primarily cognitive dysfunction are the glycine transporter-1 inhibitor BI-425809 and cannabidiol. Therapies targeting residual positive symptoms/treatment-resistant schizophrenia include pimavanserin, dopamine D1/D2 antagonist LuAF-35700, and DAAO inhibitor sodium benzoate. Two new long-acting injectable antipsychotic formulations, Aripiprazole Lauroxil NanoCrystal® and the first subcutaneous injectable LAI Perseris (RBP-7000), were recently approved by U.S. Food and Drug Administration, and positive results were announced for Risperidone ISM®, each achieving therapeutic levels within 24 hours, without need for initial oral cotreatment/loading injection-strategies. Paliperidone palmitate 6-monthly intramuscularly injectable and Risperidone subcutaneously injectable TV46000 are currently under investigation. Finally, the samidorphan+olanzapine combination targets reduced weight gain liability, while maintaining olanzapine's efficacy. Most of these trial programs are still ongoing or have yielded mixed or even negative results. Thus, additional mechanisms of action and agents require study to improve schizophrenia outcomes for total/positive symptoms with reduced adverse effects, but also cognitive symptoms, negative symptoms, and treatment resistance, the areas of greatest need in schizophrenia currently.
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7.
Co-shared genetics and possible risk gene pathway partially explain the comorbidity of schizophrenia, major depressive disorder, type 2 diabetes, and metabolic syndrome.
Postolache, TT, Del Bosque-Plata, L, Jabbour, S, Vergare, M, Wu, R, Gragnoli, C
American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. 2019;(3):186-203
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Abstract
Schizophrenia (SCZ) and major depressive disorder (MDD) in treatment-naive patients are associated with increased risk for type 2 diabetes (T2D) and metabolic syndrome (MetS). SCZ, MDD, T2D, and MetS are often comorbid and their comorbidity increases cardiovascular risk: Some risk genes are likely co-shared by them. For instance, transcription factor 7-like 2 (TCF7L2) and proteasome 26S subunit, non-ATPase 9 (PSMD9) are two genes independently reported as contributing to T2D and SCZ, and PSMD9 to MDD as well. However, there are scarce data on the shared genetic risk among SCZ, MDD, T2D, and/or MetS. Here, we briefly describe T2D, MetS, SCZ, and MDD and their genetic architecture. Next, we report separately about the comorbidity of SCZ and MDD with T2D and MetS, and their respective genetic overlap. We propose a novel hypothesis that genes of the prolactin (PRL)-pathway may be implicated in the comorbidity of these disorders. The inherited predisposition of patients with SCZ and MDD to psychoneuroendocrine dysfunction may confer increased risk of T2D and MetS. We illustrate a strategy to identify risk variants in each disorder and in their comorbid psychoneuroendocrine and mental-metabolic dysfunctions, advocating for studies of genetically homogeneous and phenotype-rich families. The results will guide future studies of the shared predisposition and molecular genetics of new homogeneous endophenotypes of SCZ, MDD, and metabolic impairment.
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8.
Association between Serum Lipids and Antipsychotic Response in Schizophrenia.
Kim, DD, Barr, AM, Fredrikson, DH, Honer, WG, Procyshyn, RM
Current neuropharmacology. 2019;(9):852-860
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Abstract
Metabolic abnormalities are serious health problems in individuals with schizophrenia. Paradoxically, studies have noted an association where individuals who gained body weight or who have increased their serum lipids demonstrated a better antipsychotic response. As serum lipids serve as more specific physiological markers than body weight, the objective of this study was to review studies that examined the association between changes in serum lipids and changes in symptoms during antipsychotic treatment in individuals with schizophrenia. A Medline® literature search was performed. Fourteen studies were included and analyzed. Evidence suggests that increases in serum lipids may be associated with decreases in symptoms during antipsychotic treatment. This inverse association may be independent of confounding variables, such as weight gain, and may be most evident during treatment with clozapine. Also, according to recent randomized controlled trials, lipid-lowering agents do not appear to worsen symptoms although this needs to be further investigated in clozapine-treated patients. Future studies should investigate the association in question in a larger population and identify underlying mechanisms.
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Principi di farmacodinamica e farmacocinetica nello switch tra antipsicotici: focus su cariprazina.
Fagiolini, A, Bolognesi, S, Goracci, A, Beccarini Crescenzi, B, Cuomo, A
Rivista di psichiatria. 2019;(6):1-6
Abstract
Cariprazina {RGH-188; trans-N- [4- [2- [4- (2,3-diclorofenil) piperazin-1-il] etil] cicloesil] -N_, N_-dimetilurea cloridrato} è un antipsicotico atipico di nuova generazione, con un originale profilo farmacodinamico e farmacocinetico. Cariprazina ha due metaboliti attivi, uno dei quali ha un'emivita di 1-3 settimane, che è la più lunga di qualsiasi antipsicotico atipico, con emivita effettiva funzionale totale (cariprazina più due metaboliti) di 7 giorni. Il farmaco mostra un'affinità che è circa 10 volte più alta per i recettori D3 che per D2 (rispettivamente pKi 10,07 e 9,31). L'affinità per D3 è superiore all'affinità della stessa dopamina. Cariprazina mostra inoltre un'elevata affinità per i recettori 5-HT2B (pKi 9,24), con antagonismo puro. Cariprazina è un agonista parziale e ha un'affinità significativa, ma inferiore all'affinità per D3, sui recettori 5-HT1A (pKi 8,59). Agendo su D3 e 5-HT1, cariprazina migliora i sintomi negativi, l'anedonia e i deficit cognitivi. L'affinità per i recettori 5-HT2A (pKi 7,73), H1 (pKi 7,63) e 5-HT2C (pKi 6,87) è inferiore, così come minori sono le affinità per i recettori adrenergici, istaminergici e colinergici, recettori che sono spesso responsabili di effetti collaterali. Grazie al profilo di tollerabilità (sicurezza cardiovascolare, bassa probabilità di dare sedazione e iperprolattinemia, basso rischio metabolico), insieme alla sua peculiare efficacia sui sintomi negativi e alla sua lunga emivita, che spesso migliora la scarsa aderenza, cariprazina è un candidato valido per il passaggio da un antipsicotico inefficace (o parzialmente efficace, con particolare riferimento ai sintomi negativi), poco tollerato, o assunto con una scarsa aderenza. Questo articolo esamina le caratteristiche farmacocinetiche e farmacodinamiche di cariprazina e discute le loro implicazioni in termini di identificazione dei pazienti che possano beneficiare di un passaggio a cariprazina, e della migliore strategia per completare lo switch con successo.
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10.
An update on the efficacy of anti-inflammatory agents for patients with schizophrenia: a meta-analysis.
Çakici, N, van Beveren, NJM, Judge-Hundal, G, Koola, MM, Sommer, IEC
Psychological medicine. 2019;(14):2307-2319
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Abstract
BACKGROUND Accumulating evidence shows that a propensity towards a pro-inflammatory status in the brain plays an important role in schizophrenia. Anti-inflammatory drugs might compensate this propensity. This study provides an update regarding the efficacy of agents with some anti-inflammatory actions for schizophrenia symptoms tested in randomized controlled trials (RCTs). METHODS PubMed, Embase, the National Institutes of Health website (http://www.clinicaltrials.gov), and the Cochrane Database of Systematic Reviews were systematically searched for RCTs that investigated clinical outcomes. RESULTS Our search yielded 56 studies that provided information on the efficacy of the following components on symptom severity: aspirin, bexarotene, celecoxib, davunetide, dextromethorphan, estrogens, fatty acids, melatonin, minocycline, N-acetylcysteine (NAC), pioglitazone, piracetam, pregnenolone, statins, varenicline, and withania somnifera extract. The results of aspirin [mean weighted effect size (ES): 0.30; n = 270; 95% CI (CI) 0.06-0.54], estrogens (ES: 0.78; n = 723; CI 0.36-1.19), minocycline (ES: 0.40; n = 946; CI 0.11-0.68), and NAC (ES: 1.00; n = 442; CI 0.60-1.41) were significant in meta-analysis of at least two studies. Subgroup analysis yielded larger positive effects for first-episode psychosis (FEP) or early-phase schizophrenia studies. Bexarotene, celecoxib, davunetide, dextromethorphan, fatty acids, pregnenolone, statins, and varenicline showed no significant effect. CONCLUSIONS Some, but not all agents with anti-inflammatory properties showed efficacy. Effective agents were aspirin, estrogens, minocycline, and NAC. We observed greater beneficial results on symptom severity in FEP or early-phase schizophrenia.