Chemically modified electrodes for the detection of antidepressants

Major depressive disorder is a widespread condition with antidepressants as the main pharmacological treatment. However, some patients experience concerning adverse reactions or have an inadequate response to treatment. Analytical chromatographic techniques, among other techniques, are valuable tools for investigating medication complications, including those associated with antidepressants. Nevertheless, there is a growing need to address the limitations associated with these techniques. In recent years, electrochemical (bio)sensors have garnered significant attention due to their lower cost, portability, and precision. Electrochemical (bio)sensors can be used for various applications related to depression, such as monitoring the levels of antidepressants in biological and in environmental samples. They can provide accurate and rapid results, which could facilitate personalized treatment and improve patient outcomes.info:eu-repo/semantics/publishedVersio

Electrochemical chemically based sensors and emerging enzymatic biosensors for antidepressant drug detection: a review

Major depressive disorder is a widespread condition with antidepressants as the main pharmacological treatment. However, some patients experience concerning adverse reactions or have an inadequate response to treatment. Analytical chromatographic techniques, among other techniques, are valuable tools for investigating medication complications, including those associated with antidepressants. Nevertheless, there is a growing need to address the limitations associated with these techniques. In recent years, electrochemical (bio)sensors have garnered significant attention due to their lower cost, portability, and precision. Electrochemical (bio)sensors can be used for various applications related to depression, such as monitoring the levels of antidepressants in biological and in environmental samples. They can provide accurate and rapid results, which could facilitate personalized treatment and improve patient outcomes. This state-of-the-art literature review aims to explore the latest advancements in the electrochemical detection of antidepressants. The review focuses on two types of electrochemical sensors: Chemically modified sensors and enzyme-based biosensors. The referred papers are carefully categorized according to their respective sensor type. The review examines the differences between the two sensing methods, highlights their unique features and limitations, and provides an in-depth analysis of each sensor.info:eu-repo/semantics/publishedVersio

Design and optimization of an electrochemical genosensing platform for BDNF Val66Met polymorphism detection

Major depressive disorder (MDD) is a debilitating and highly prevalent psychiatric illness.  Antidepressant drugs (AD) have remained the main pharmacological treatment for this condition, and since their discovery and despite their high efficacy, insufficient remission rates and treatment-resistant depression remain a cause of concern for clinicians. The BDNF gene is an extensively studied gene regarding depression and AD response rates. Moreover, the rs6265 (Val66Met) non-synonymous single nucleotide polymorphism (SNP) has been linked to variable remission rates to ADs. Therefore, there is a growing interest in genotyping approaches to detect SNPs, such as the Val66Met, to better suit patients’ needs. Current SNP identification procedures are based on the polymerase-chain reaction (PCR) technique. This methodology, although extremely efficacious, is time-consuming, requires expensive equipment and highly trained personnel. Thus, the development of cheaper, faster and lower-cost genotyping tools, such as electrochemical genosensors, capable of detecting an electrochemical signal from a hybridization event between DNA probes, is warranted. To develop a genotyping platform based on the electrochemical biosensing principles, capable of distinguishing Val66Met genotypes. 2 specific target DNA sequences of interest from the Val66Met SNP were selected and designed. Employing screen-printed gold electrodes (SPGE) as transducers, the genosensor development protocol included four stages: pre-treatment; sensing phase; sandwich DNA hybridization and electrochemical detection. The electrochemical detection was carried out through chronoamperometry techniques. Several experimental conditions, such as capture probe and antibody concentrations, were successfully optimized. Furthermore, a calibration curve employing different target concentrations was obtained.  The DNA sequence complementary to the capture probe showed greater current signals than the non-complementary, as expected. The developed methodology showed consistent results, with the genosensor exhibiting the ability to distinguish between both DNA targets. A linear relationship between DNA target concentration and current intensity was achieved between 0.10 nmolL-1 to 2.0 nmolL-1.info:eu-repo/semantics/publishedVersio

Development of an electrochemical genosensor for the detection of BDNF Val66Met polymorphism

Major depressive disorder (MDD) is one of the most prevalente psychiatric conditions, with a problematic etiopethogenesis. Antidepressant drugs remain the gold standard for the treatment of depressed patients. Yet, their efficacy in clinical treatments remain a cause of concern for the medical community, as 30 to 40% of patients do not respond sufficiently to these drugs. Gentic variety is a crucial factor involved in MDD, influencing the remission rates of patients undergoing antidepressant treatment, and literature has found the BDNF gene to be na essential player on this situation. This gene codes for a neurotrophin of the same name, wich has been shown to be essential in neuroplasticity and neurogenesis. Moreover, the rs6265 (Val66Met) genetic polymorphism has been widely studied as a cause of variation in patient’s antodepressant response rates. Personalizing antidepressant tratments is becoming increasingly more required. However, conventional genotyping methodologies have some intrinsic drawbacks, such as high equipment costs and lengthy experimente periods. Consequently, there is na increasing demand for quicker, less expensive approaches to genotype these individuals. Genosensors meet these requirements and can be advantageous in the detection of polymorphisms. In this thesis, a novel low-cost electrochemical genosensensing platform, capable of detecting the Val66Met polymorphism, was developed and optimized. The working principle of the genosensor is its capability to recognize and detect the DNA hybridization reactions between two complementary DNA sequences. Two specific target DNA sequences of interest from the Val66Met polymorphism (one for the Val variant and another for the Met variant) were designed and selected in-silico. The construction of the genosensor involved 4 main steps: pre-treatment; sensing phase; sandwich DNA hybridization assay and electrochemical detection. After the optimization of a variety of experimental conditions, namely DNA capture probe concentration, MCH concentration and incubation time, homogeneous and heterogeneous hybridization steps and anti-FITC-POD antibody concentration and incubation time, calibration curves were plotted, revealing a linear correlation between the electrochemical current and DNA target concentration from 0.1 to 2.0 nM. The genosensor also showed good ability to discriminate between both target sequences, with a limit of quantifiation of 0.057 nM. The developed genosensor demonstrated to be a promising and effective tool for detection od Val66Met genetic polymorphism

Is there a link between NRF2 and depression?

Depression is a common mental health disorder that affects millions of people worldwide. Recent studies have highlighted the role of oxidative stress and inflammation in the pathogenesis of depression. NRF2 is a transcription factor that plays a crucial role in cellular defense against oxidative stress by binding to antioxidant response elements (AREs) located in the promoter region of various phase II antioxidant enzymes and stress-responsive enzymes. Decreased Keap1-Nrf2 signaling has been implicated in the development of mood disorders, such as Major Depressive Disorder. Therefore, this review aims to evaluate the in vitro and in vivo evidence of the involvement of Nrf2 in depression. A review was conducted on the PubMed database for articles published until March 8, 2022 Papers that evaluated NRF2 in animals and/or cell lines with depression and were published in English were included in the review. Studies that addressed other diseases/topics, systematic reviews, and those that did not address NRF2 were excluded. Quality assessment was performed according to Koch et al., 2022. Out of the 203 possibly relevant abstracts found through the PubMed search, 45 papers were included in the review. The results suggest that Nrf2 levels tend to decrease in animals exposed to oxidative stress or depressive behavior. When animals were treated with antidepressants or anti-inflammatory drugs, Nrf2 levels increased. Additionally, the study found that IL-10 and BDNF were key elements that were positively influenced by Nrf2 levels, protecting against oxidative stress through Keap1/Nrf2. The findings suggest that Nrf2 activation may play a crucial role in controlling oxidative stress and inflammation during depression. Furthermore, it provides evidence of the involvement of Nrf2 in depression and highlights its potential as a therapeutic target. However, further studies on clinical samples are necessary to evaluate NRF2’s putative effect in depression and antidepressant response.info:eu-repo/semantics/publishedVersio

Construction and optimization of an electrochemical genosensor for the detection of BDNF gene Val66Met polymorphism

Major depression disorder (MDD) is the most prevalent psychiatric condition worldwide. Currently, antidepressants constitute the main pharmacological treatment for this condition. Despite the growing arsenal of antidepressant medications, almost half of MDD patients have insufficient remission rates during their treatments. A growing body of scientific evidence points to genetic factors as having a crucial role in patients’ response to antidepressant treatments. One of these genetic components is the BDNF gene, that codes for the BDNF neurotrophin, an important player in neuroplasticity and neurogenesis.info:eu-repo/semantics/publishedVersio

Detecting BDNF gene polymorphisms using genosensors and molecular biology tools

Major depressive disorder (MDD) is a complex and highly prevalent psychiatric disorder with a high impact on quality of life and negative effects on mood, behaviour, and cognition. Currently, the main medical treatment for MDD is antidepressant medication. The selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, sertraline, fluvoxamine, paroxetine and citalopram, are the most commonly prescribed drugs. However, as with all antidepressant treatments, about 30–40% of MDD patients do not respond sufficiently to SSRIs. Several factors, including genetic factors, play important roles in antidepressant responses. BDNF is one of the most investigated genes regarding depression and antidepressant response. In fact, the rs6265 (Val66Met) non-synonymous polymorphism, has been demonstrated to decrease pro-BDNF processing, and consequently affect the dependent secretion of BDNF. Curiously, carriers of Met-allele have been described to have smaller hippocampal volume, either in healthy or depressed patients. So, it is likely they can contribute to the interindividual differences in patient´s responses to antidepressants. Therefore, it is crucial to develop methodologies to predict the individual antidepressant response. In this work, two analytical approaches based in molecular biology and electrochemical genosensor techniques are under development to create a low-cost genotyping platform able to genotype BDNF SNPs related with antidepressants therapeutic response.info:eu-repo/semantics/publishedVersio

Bdnf-NRF2 crosstalk in depression disorder

The World Health Organization estimates that major depressive disorder (MDD) affects over 264 million individuals globally, posing a significant public health challenge. Treatment-resistant depression (TRD) represents a severe form of MDD with poor treatment outcomes. Genetic variations are known to impact MDD treatment responses, yet genome-wide association studies have struggled to identify consistent marker alleles. Previous research has linked the Brain Derived Neurotrophic Factor (BDNF) genetic polymorphism with TRD. BDNF is essential for neuronal survival and neuroplasticity, processes influenced by antidepressant treatment, and regulated by transcription factors like Nuclear factor erythroid 2-related factor 2 (NRF2). NRF2 regulates antioxidant and anti-inflammatory responses and plays a crucial role in depression pathogenesis. NRF2 knockout mice exhibit reduced BDNF levels and depression-like behaviors, indicating that NRF2activation enhances BDNF expression and antidepressant efficacy. The BDNF rs6265 (Val66Met) polymorphism is associated with variations in antidepressant response rates. Research suggests that the interaction between BDNF and NRF2 pathways could enhance antidepressant effectiveness. NRF2 activation, such as through the compound sulforaphane, has demonstrated rapid antidepressant effects by increasing BDNF expression. Lower levels of NRF2 and BDNF are observed in stress-induced depression models, and ketamine treatment influences NRF2-related genes. Simultaneously, there is a growing need for efficient genotyping methods, and genosensors offer a promising solution. This presentation will address the interplay between BDNF and NRF2 in depression, explore its relationship in antidepressant response, and present a putative genosensor for BDNF rs6265 (Val66Met) polymorphism identification, improving antidepressant treatment outcome.info:eu-repo/semantics/publishedVersio

Avaliação da atividade antioxidante do extrato etanólico da Adansonia digitata

O Baobá (Adansonia digitata) é uma planta africana usada na medicina tradicional devido às suas propriedades antioxidantes, resultante da sua composição em compostos fenólicos, que desempenham um papel importante na prevenção de doenças associadas ao stress oxidativo. O principal objetivo deste trabalho é avaliar a atividade antioxidante do extrato etanólico de A. digitata. Estudo experimental com análise do extrato etanólico 70 % (V/V) de A. digitataproveniente do fruto seco, obtido comercialmente. A aferição da atividade antioxidante foi feita através de diferentes ensaios: radical (2,2-diphenyl-1-picrylhydrazyl (DPPH), poder redutor do ferro (FRAP) e quelação da ferrozina. No ensaio FRAP a maior percentagem de redução do ferro foi 2,75 %, obtida com a maior concentração testada (1000 μg/ml). Em relação ao ensaio da ferrozina, as percentagens de quelação do ferro variaram entre 19,88 ± 2,50 % e 27,08 ± 8,64 %, onde a percentagem mais elevada foi obtida com a concentração de 30 μg/ml. Os resultados foram inferiores aos do controlo positivo (EDTA), cujas percentagens de inibição rondaram os 100 %. No ensaio do DPPH, o extrato do baobá obteve um IC50 de 656,97 ± 12,45 μg/ml, valor muito acima do controlo positivo usado, a quercetina (IC50 = 1,8 μg/ml). Os estudos de avaliação da atividade antioxidante existentes na literatura com a planta têm sido realizados com diferentes solventes (ex: água, metanol, acetona) e partes da planta (ex: folhas, polpa do fruto). Num estudo de Irondi et al., (2016) o extrato metanólico, proveniente de folhas de baobá, demonstrou um valor de IC50 para o ensaio de DPPH de 230 ± 0,01 μg/ml. Por sua vez, num estudo de Ismail et al., (2019) os melhores valores de FRAP foram obtidos com 80% acetona (5141,19 ± 45,37 mg Trolox/100 g peso seco); os melhores valores de DPPH obtiveram-se com acetona acídica (acetona + água + HCl) (80:19:1; V/V/V) (2501,46 ± 50,61 mg Trolox/100 g peso seco) e com 80% acetona (2390,07 ± 49,15 mg Trolox/100 g peso seco). Alguns autores consideram que os extratos vegetais têm uma atividade antioxidante elevada ou significativa quando os ensaios apresentam valores de IC50 100 μg/ml. Os resultados obtidos neste estudo demonstram que o extrato de baobá analisado parece ter uma baixa atividade antioxidante. Contudo, são necessários mais estudos com a planta, utilizando ensaios complementares e diferentes técnicas extrativas,no sentido de confirmar o potencial antioxidante do extrato etanólico de baobá.info:eu-repo/semantics/publishedVersio