Alzheimer’s disease (AD) is a progressive and neurodegenerative illness which results in alterations in cognitive development. It is characterized by loss/dysfunction of cholinergic neurons, and formation of amyloid plaques, and formation of neurofibrillary tangles, among other changes, due to hyperphosphorylation of tau-protein. Exposure to pesticides in humans occurs frequently due to contact with contaminated food, water, or particles. Organochlorines, organophosphates, carbamates, pyrethroids and neonicotinoids are associated with the most diagnosed incidents of severe cognitive impairment. The aim of this study was to determine the effects of these pesticides on the phosphorylation of tau protein, and its cognitive implications in the development of AD. It was found that exposure to pesticides increased the phosphorylation of tau protein at sites Ser198, Ser199, Ser202, Thr205, Ser396 and Ser404. Contact with these chemicals altered the enzymatic activities of cyclin-dependent kinase 5 and glycogen synthase kinase 3 beta, and protein phosphatase-2A. Moreover, it altered the expression of the microtubule associated protein tau gene, and changed levels of intracellular calcium. These changes affected tau protein phosphorylation and neuroinflammation, and also increased oxidative stress. In addition, the exposed subjects had poor level of performance in tests that involved evaluation of novelty, as test on verbal, non-verbal, spatial memory, attention, and problem-solving skills.

Pesticides are chemical substances used to control, prevent, or destroy agricultural, domestic, and livestock pests. These compounds produce adverse changes in health, and they have been associated with the development of multiple chronic diseases. This study aimed to present a detailed review of the effect of pesticides on the oral cavity and the oral microbiome. In the oral cavity, pesticides alter and/or modify tissues and the microbiome, thereby triggering imbalance in the ecosystem, generating an inflammatory response, and activating hydrolytic enzymes. In particular, the imbalance in the oral microbiome creates a dysbiosis that modifies the number, composition, and/or functions of the constituent microorganisms and the local response of the host. Pesticide exposure alters epithelial cells, and oral microbiota, and disrupts the homeostasis of the oral environment. The presence of pesticides in the oral cavity predisposes the appearance of pathologies such as caries, periodontal diseases, oral cancer, and odontogenic infections. In this study, we analyzed the effect of organochlorines, organophosphates, pyrethroids, carbamates, bipyridyls, and triazineson oral cavity health and ecosystems.

Oxidative stress levels are exacerbated in Alzheimer’s disease (AD). This phenomenon feeds back into the overactivation of oxidase enzymes, mitochondrial dysfunction, and the formation of advanced glycation end-products (AGEs), with the stimulation of their receptors (RAGE). These factors stimulate Aβ peptide aggregation and tau hyperphosphorylation through multiple pathways, which are addressed in this paper. The aim of this study was to evaluate the regulatory effect of N-acetyl cysteine (NAC) on oxidant/antioxidant balance as an adjuvant treatment in patients with AD. The results obtained showed that NAC supplementation produced improved cognitive performance, decreased levels of oxidative stress markers, lowered activities of oxidase enzymes, increased antioxidant responses, and attenuated inflammatory and apoptotic markers. Moreover, NAC reversed mitochondrial dysfunction, lowered AGEs-RAGE formation, attenuated Aβ peptide oligomerization, and reduced phosphorylation of tau, thereby halting the formation of neurofibrillary tangles and the progression of AD.

Pesticides are chemicals used in agricultural fields for the prevention or destruction of pests. Inappropriate use of these substances, as well as handling them without using personal protective equipment, may result in serious health problems such as neurodegenerative diseases and mental disorders. Previous studies have demonstrated the adverse effects of pesticides on brain function. However, some researchers have associated pesticide poisoning with the development of disorders such as dissociative amnesia, multiple personality disorders, and depersonalization disorder. The objective of this work was to perform a bibliographic review of the relationship between pesticide poisoning and the development of dissociative disorders. Previous studies suggest that the duration of pesticide exposure is a major determinant in the development of dissociative diseases and disorders. The information obtained in this review suggests that there is no specific relationship between dissociative disorders and pesticide poisoning. However, these results point to associating the most representative symptoms of dissociative disorder (such as amnesia and memory loss) with pesticide exposure. Based on the bibliographic search, possible mechanisms of action were suggested in an attempt to explain a possible association between exposure to pesticides and the appearance of dissociative disorders.

The COVID-19 pandemic has proven to be a challenge for healthcare systems, especially in terms of the care of patients with Alzheimer’s disease (AD). Age is one of the major risk factors for severe forms of COVID-19, most probably due to the presence of comorbidities and inflammations. It is known that SARS-CoV-2 invades nerve endings and olfactory nerves through the binding of the spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor. This interaction triggers an inflammatory cascade that results in cognitive impairment. In turn, the isoform of apolipoprotein-E4 (APOE-4ε) in AD is a risk factor for increased neuroinflammation through microglia activation, increased oxidative stress, and neurodegeneration. AD and SARS-CoV-2 are associated with increases in levels of inflammatory markers, as well as increases in levels of APOE-4ε, ACE2 and oxidative stress. Thus, there is a synergistic relationship between AD and SARS-CoV-2. In addition, the social isolation and other health measures resulting from the pandemic have led to a higher level of anxiety and depression among AD patients, a situation which may lead to a decline in cognitive function. Therefore, there is a need to develop strategies for keeping the patient calm but active.

Introduction: In humans, there are sets of genes that encode enzymes that decrease or increase the risks derived from exposure to pesticides. These include DNA repair genes (XRCC1, OGG1 and XRCC4); pesticide metabolizers (GSTP1 and PON1), and genes that act against oxidative stress (SOD2 and...