Pesticides: classifications, exposure and risks to human health

Pesticides are used in the control and prevention of pests, improving the productivity and the quality of agricultural production. The adoption of the Brazilian agricultural model, which uses pesticides on a large scale and indiscriminately, has been worrying public authorities about their impacts on human health and environmental sustainability. Thus, studies that contribute to a better understanding of agrochemicals and their effects on ecosystems and human health are timely. The aim was to investigate the history of the production and use of pesticides, their classifications, sources of exposure and their risks to human health. The research was carried out through literature review in databases to verify scientific information about the history of pesticides, structural and toxicological classifications, sources of exposure and their risks to human health. The use of pesticides dates back many years. During the nineteenth century until the mid-twentieth century, some chemicals nowadays used was pesticides were used for public health or for war purposes. About the classification of pesticides, due to the different biological targets, the agrochemicals market is segmented into different action targets (herbicides, fungicides and insecticides). Pesticides can be classified as contact, ingestion or systemic according to the mode of action. As for the chemical structure, the main classes of pesticides are organochlorines, organophosphates, pyrethroids and carbamates. The toxicity of pesticides ranges from low toxic to extremely toxic. Exposure to pesticides can occur directly through occupational exposure, or indirectly, through environmental exposure and food. The impacts on human health are divided into acute and chronic form. The prolonged human exposure to pesticides may result in neurological, reproductive, teratogenic and immunological disorders. The results presented in this literature review contribute to a better understanding of agrochemicals and their effects on human health

Experimental Infection by Brucella ovis: Changes in NTPDase, 5'-Nucleotidase and Acetylcholinesterase Associated Cerebral Oxidative Stres

Background: Changes in purinergic and cholinergic signaling have been demonstrated in various pathologies associated with inflammation; however, the changes in brucellosis caused by the Gram-negative coccobacillus Brucella ovis are not known. B. ovis is generally asymptomatic in sheep. Hepatosplenomegaly has been described in B. ovis, a non-zoonotic species, characterized by an extravascular inflammatory response. Purinergic system enzymes are closely involved with the modulation of the immune system, pro- and anti-inflammatory events. The objective of this study was to investigate the role of ectonucleotidases and cholinesterase’s in the brains of mice experimentally infected with B. ovis.Materials, Methods & Results: Forty-eight animals were divided into two groups: control (n = 24) and infected (n = 24). In group infected, 100 µL containing 1.3 x 107 UFC B. ovis /mL via intraperitoneal was used in inoculation. The brains were collected from the animals on days 7, 15, 30 and 60 post-infection (PI). We measured levels of TBARS (substances reactive to thiobarbituric acid) and ROS (reactive oxygen species) in the brain. The activity of NTPDase (using ATP and ADP as substrate) and 5'-nucleotidase (using AMP as substrate) were evaluated in brain in addition to histopathological analysis. No histopathological lesions were observed in the control group nor the infected group at days 7, 15, and 30 PI. However,multifocal areas with moderate microgliosis and inflammatory infiltrates in the cerebral cortex were observed at day 60 PI in the infected animals. B. ovis DNA was detected in brain. During the course of infection, B. ovis caused greater lipid peroxidation in the brains of infected animals than in the control group at day 60PI. No significant results were observed at 7, 15 or day 30 PI. Similarly, there was significantly more reactive oxygen species at day 60 PI in brains of infected animals than in the control group. NTPDase activity (using ATP and AMP as substrate) was lower at days 7 and 15 PI in infected animals than in control. However, during the course of infection there was an increase in NTPDase activity at day 60 PI in the infected group. The infected animals showed a decrease of 5´-nucleotidase (AMP as substrate) activity at days 7 and 30 PI. On the other hand, 5´-nucleotidase activity was greater on day 60 PI in the experimental group than in the control. The results suggest that nucleotide hydrolysis was low in the acute phase (up to day 30 PI) due to the decrease of NTPDase and 5´-nucleotidase activities. After day 60 PI, there was a reversal in enzyme activities, probably with concomitant increase of extracellular nucleotides. AChE activity in brain on days 30 and 60 PI compared to control.Discussion: Among the functions of NTPDase are inhibition of platelet aggregation, vascular homeostasis, modulation of inflammation and immune response, all via its regulation of extracellular concentrations of ATP, a pro-inflammatory molecule. E-NTPDase plays an important role in controlling lymphocyte function, including antigen recognition and activation of cytotoxic T cell effector functions, as well as the generation of signals. The enzyme E-5´-nucleotidase also exerts non-enzymatic functions, including induction of intracellular signaling and mediation of cell-cell adhesion and cell-matrix and migration. Levels of acetylcholine are regulated by cholinesterase enzymes that are present in cholinergic and noncholinergic tissues, as the acetylcholinesterase (AChE) is a membrane-bound enzyme, primarily found in the brain and cholinergic neurons, where it participates in the structural regulation of postsynaptic differentiation. The results demonstrated that the chronicity of infection by B. ovis causes oxidative damage and inflammation in the brain, as well as modulation of ectonucleotidases and AChE activities

Coffee, caffeine, chlorogenic acid, and the purinergic system

Coffee is a drink prepared from roasted coffee beans and is lauded for its aroma and flavour. It is the third most popular beverage in the world. This beverage is known by its stimulant effect associated with the presence of methylxanthines. Caffeine, a purine-like molecule (1,3,7 trymetylxantine), is the most important bioactive compound in coffee, among others such as chlorogenic acid (CGA), diterpenes, and trigonelline. CGA is a phenolic acid with biological properties as antioxidant, anti-inflammatory, neuroprotector, hypolipidemic, and hypoglicemic. Purinergic system plays a key role inneuromodulation and homeostasis. Extracellular ATP, other nucleotides and adenosine are signalling molecules that act through their specific receptors, namely purinoceptors, P1 for nucleosides and P2 for nucleotides. They regulate many pathological processes, since adenosine, for instance, can limit the damage caused by ATP in the excitotoxicity from the neuronal cells. The primary purpose of this review is to discuss the effects of coffee, caffeine, and CGA on the purinergic system. This review focuses on the relationship/interplay between coffee, caffeine, CGA, and adenosine, and their effects on ectonucleotidases activities as well as on the modulation of P1 and P2 receptors from central nervous system and also in peripheral tissue

Crosstalk between the Purinergic and Immune Systems: Implications for the Glutathione Antioxidant System in Health and Disease

Glutathione (GSH) represents the major nonprotein thiol in cells and, alongside with glutathione-dependent enzymes such as glutathione reductase (GR), glutathione peroxidase (GPx), and glutathione S-transferase (GST), exerts several biological functions including the protection against free radicals and other essential metabolic reactions within the body. Disturbances in the homeostasis of this complex glutathione antioxidant system may damage cells and have been implicated with the development and progression of several human diseases. In this context, the immune and purinergic systems are also essential, since the dysregulation in both systems may also be correlated with numerous diseases. These two networks are closely related and control inflammatory responses, especially by the crosstalk of signaling molecules, receptors, and enzymes; thus, they can exacerbate or slow down the progression of diseases. Based on this background, we aimed to provide a general scenario of the purinergic and immune systems and the connection between both and the modulation of glutathione and glutathione-dependent enzyme expression and activity in the context of health and disease

Potential Therapeutic Role of Purinergic Receptors in Cardiovascular Disease Mediated by SARS-CoV-2

Novel coronavirus disease 2019 (COVID-19) causes pulmonary and cardiovascular disorders and has become a worldwide emergency. Myocardial injury can be caused by direct or indirect damage, particularly mediated by a cytokine storm, a disordered immune response that can cause myocarditis, abnormal coagulation, arrhythmia, acute coronary syndrome, and myocardial infarction. The present review focuses on the mechanisms of this viral infection, cardiac biomarkers, consequences, and the possible therapeutic role of purinergic and adenosinergic signalling systems. In particular, we focus on the interaction of the extracellular nucleotide adenosine triphosphate (ATP) with its receptors P2X1, P2X4, P2X7, P2Y1, and P2Y2 and of adenosine (Ado) with A2A and A3 receptors, as well as their roles in host immune responses. We suggest that receptors of purinergic signalling could be ideal candidates for pharmacological targeting to protect against myocardial injury caused by a cytokine storm in COVID-19, in order to reduce systemic inflammatory damage to cells and tissues, preventing the progression of the disease by modulating the immune response and improving patient quality of life

Pesticides: classifications, exposure and risks to human health

Pesticides are used in the control and prevention of pests, improving the productivity and the quality of agricultural production. The adoption of the Brazilian agricultural model, which uses pesticides on a large scale and indiscriminately, has been worrying public authorities about their impacts on human health and environmental sustainability. Thus, studies that contribute to a better understanding of agrochemicals and their effects on ecosystems and human health are timely. The aim was to investigate the history of the production and use of pesticides, their classifications, sources of exposure and their risks to human health. The research was carried out through literature review in databases to verify scientific information about the history of pesticides, structural and toxicological classifications, sources of exposure and their risks to human health. The use of pesticides dates back many years. During the nineteenth century until the mid-twentieth century, some chemicals nowadays used was pesticides were used for public health or for war purposes. About the classification of pesticides, due to the different biological targets, the agrochemicals market is segmented into different action targets (herbicides, fungicides and insecticides). Pesticides can be classified as contact, ingestion or systemic according to the mode of action. As for the chemical structure, the main classes of pesticides are organochlorines, organophosphates, pyrethroids and carbamates. The toxicity of pesticides ranges from low toxic to extremely toxic. Exposure to pesticides can occur directly through occupational exposure, or indirectly, through environmental exposure and food. The impacts on human health are divided into acute and chronic form. The prolonged human exposure to pesticides may result in neurological, reproductive, teratogenic and immunological disorders. The results presented in this literature review contribute to a better understanding of agrochemicals and their effects on human health

Experimental Infection by Brucella ovis: Changes in NTPDase, 5'-Nucleotidase and Acetylcholinesterase Associated Cerebral Oxidative Stres

Background: Changes in purinergic and cholinergic signaling have been demonstrated in various pathologies associated with inflammation; however, the changes in brucellosis caused by the Gram-negative coccobacillus Brucella ovis are not known. B. ovis is generally asymptomatic in sheep. Hepatosplenomegaly has been described in B. ovis, a non-zoonotic species, characterized by an extravascular inflammatory response. Purinergic system enzymes are closely involved with the modulation of the immune system, pro- and anti-inflammatory events. The objective of this study was to investigate the role of ectonucleotidases and cholinesterase’s in the brains of mice experimentally infected with B. ovis.Materials, Methods & Results: Forty-eight animals were divided into two groups: control (n = 24) and infected (n = 24). In group infected, 100 µL containing 1.3 x 107 UFC B. ovis /mL via intraperitoneal was used in inoculation. The brains were collected from the animals on days 7, 15, 30 and 60 post-infection (PI). We measured levels of TBARS (substances reactive to thiobarbituric acid) and ROS (reactive oxygen species) in the brain. The activity of NTPDase (using ATP and ADP as substrate) and 5'-nucleotidase (using AMP as substrate) were evaluated in brain in addition to histopathological analysis. No histopathological lesions were observed in the control group nor the infected group at days 7, 15, and 30 PI. However,multifocal areas with moderate microgliosis and inflammatory infiltrates in the cerebral cortex were observed at day 60 PI in the infected animals. B. ovis DNA was detected in brain. During the course of infection, B. ovis caused greater lipid peroxidation in the brains of infected animals than in the control group at day 60PI. No significant results were observed at 7, 15 or day 30 PI. Similarly, there was significantly more reactive oxygen species at day 60 PI in brains of infected animals than in the control group. NTPDase activity (using ATP and AMP as substrate) was lower at days 7 and 15 PI in infected animals than in control. However, during the course of infection there was an increase in NTPDase activity at day 60 PI in the infected group. The infected animals showed a decrease of 5´-nucleotidase (AMP as substrate) activity at days 7 and 30 PI. On the other hand, 5´-nucleotidase activity was greater on day 60 PI in the experimental group than in the control. The results suggest that nucleotide hydrolysis was low in the acute phase (up to day 30 PI) due to the decrease of NTPDase and 5´-nucleotidase activities. After day 60 PI, there was a reversal in enzyme activities, probably with concomitant increase of extracellular nucleotides. AChE activity in brain on days 30 and 60 PI compared to control.Discussion: Among the functions of NTPDase are inhibition of platelet aggregation, vascular homeostasis, modulation of inflammation and immune response, all via its regulation of extracellular concentrations of ATP, a pro-inflammatory molecule. E-NTPDase plays an important role in controlling lymphocyte function, including antigen recognition and activation of cytotoxic T cell effector functions, as well as the generation of signals. The enzyme E-5´-nucleotidase also exerts non-enzymatic functions, including induction of intracellular signaling and mediation of cell-cell adhesion and cell-matrix and migration. Levels of acetylcholine are regulated by cholinesterase enzymes that are present in cholinergic and noncholinergic tissues, as the acetylcholinesterase (AChE) is a membrane-bound enzyme, primarily found in the brain and cholinergic neurons, where it participates in the structural regulation of postsynaptic differentiation. The results demonstrated that the chronicity of infection by B. ovis causes oxidative damage and inflammation in the brain, as well as modulation of ectonucleotidases and AChE activities

Diabetes and hypertension: Pivotal involvement of purinergic signaling

Diabetes mellitus (DM) and hypertension are highly prevalent worldwide health problems and frequently associated with severe clinical complications, such as diabetic cardiomyopathy, nephropathy, retinopathy, neuropathy, stroke, and cardiac arrhythmia, among others. Despite all existing research results and reasonable speculations, knowledge about the role of purinergic system in individuals with DM and hypertension remains restricted. Purinergic signaling accounts for a complex network of receptors and extracellular enzymes responsible for the recognition and degradation of extracellular nucleotides and adenosine. The main components of this system that will be presented in this review are: P1 and P2 receptors and the enzymatic cascade composed by CD39 (NTPDase; with ATP and ADP as a substrate), CD73 (5′-nucleotidase; with AMP as a substrate), and adenosine deaminase (ADA; with adenosine as a substrate). The purinergic system has recently emerged as a central player in several physiopathological conditions, particularly those linked to inflammatory responses such as diabetes and hypertension. Therefore, the present review focuses on changes in both purinergic P1 and P2 receptor expression as well as the activities of CD39, CD73, and ADA in diabetes and hypertension conditions. It can be postulated that the manipulation of the purinergic axis at different levels can prevent or exacerbate the insurgency and evolution of diabetes and hypertension working as a compensatory mechanism

Aluminum-Induced Alterations in Purinergic System Parameters of BV-2 Brain Microglial Cells

Aluminum (Al) is ubiquitously present in the environment and known to be a neurotoxin for humans. The trivalent free Al anion (Al3+) can cross the blood-brain barrier (BBB), accumulate in the brain, and elicit harmful effects to the central nervous system (CNS) cells. Thus, evidence has suggested that Al increases the risk of developing neurodegenerative diseases, particularly Alzheimer’s disease (AD). Purinergic signaling has been shown to play a role in several neurological conditions as it can modulate the functioning of several cell types, such as microglial cells, the main resident immune cells of the CNS. However, Al effects on microglial cells and the role of the purinergic system remain elusive. Based on this background, this study is aimed at assessing the modulation of Al on purinergic system parameters of microglial cells. An in vitro study was performed using brain microglial cells exposed to Al chloride (AlCl3) and lipopolysaccharide (LPS) for 96 h. The uptake of Al, metabolism of nucleotides (ATP, ADP, and AMP) and nucleoside (adenosine), and the gene expression and protein density of purinoceptors were investigated. The results showed that both Al and LPS increased the breakdown of adenosine, whereas they decreased nucleotide hydrolysis. Furthermore, the findings revealed that both Al and LPS triggered an increase in gene expression and protein density of P2X7R and A2AR receptors, whereas reduced the A1R receptor expression and density. Taken together, the results showed that Al and LPS altered the setup of the purinergic system of microglial cells. Thus, this study provides new insights into the involvement of the purinergic system in the mechanisms underlying Al toxicity in microglial cells