Common and Trace Metals in Alzheimer's and Parkinson's Diseases

Air pollution we breathe: Assessing the air quality and human health impact in a megacity of Southeast Asia

With 24 million inhabitants and 6.6 million vehicles on the roads, Karachi, Pakistan ranks among the world's most polluted cities due to high levels of fine particulate matter (PM2.5). This study aims to investigate PM2.5 mass, seasonal and temporal variability, chemical characterization, source apportionment, and health risk assessment at two urban sites in Karachi. Samples were analyzed using ion chromatography and dual-wavelength optical transmissometer for various inorganic components (anions, cations, and trace elements) and black carbon (BC). Several PM2.5 pollution episodes were frequently observed, with annual mean concentrations at Kemari (140 ± 179 μg/m3) and Malir (95 ± 40.9 μg/m3) being significantly above the World Health Organization's guidelines of 5 μg/m3. Chemical composition at both sites exhibited seasonal variability, with higher pollution levels in winter and fall and lower concentrations in summer. The annual average BC concentrations were 4.86 ± 5.29 μg/m3 and 4.52 ± 3.68 μg/m3, respectively. A Positive Matrix Factorization (PMF) analysis identified 5 factors, crustal, sea salt, vehicular exhaust, fossil-fuel combustion, and industrial emission. The health risk assessment indicated a higher number of deaths in colder seasons (fall and winter) at the Kemari (328,794 and 287,814) and Malir (228,406 and 165,737) sites and potential non-carcinogenic and carcinogenic risks to children from metals. The non-carcinogenic risk of PM2.5 bound Pb, Fe, Zn, Mn, Cr, Cu and Ni via inhalation exposure were within the acceptable level (<1) for adults. However, potential non-carcinogenic and carcinogenic health risk posed by Pb and Cr through inhalation were observed for children. The findings exhibit critical levels of air pollution that exceed the safe limits in Karachi, posing significant health risks to children and sensitive groups. Our study underscores the urgent need for effective emission control strategies and policy interventions to mitigate these air pollution risks.

Aggregation Behavior of Amyloid Beta Peptide Depends Upon the Membrane Lipid Composition

Protein aggregation plays a crucial role in the development of several neurodegenerative diseases. It is important to understand the aggregation process for the detection of the onset of these diseases. Alzheimer's Disease (AD) is one of the most prevalent neurodegenerative diseases caused by the aggregation of Aβ-40 and Aβ-42 peptides. The smaller oligomers lead to the formation of protein plaque at the neural membranes leading to memory loss and other disorders. Interestingly, aggregation takes place at the neural membranes, therefore the membrane composition seems to play an important role in the aggregation process. Despite a large number of literatures on the effect of lipid composition on protein aggregation, there are very few concise reviews that highlight the role of membrane composition in protein aggregation. In this review, we have discussed the implication of membrane composition on the aggregation of amyloid beta peptide with a special emphasis on cholesterol. We have further discussed the role of the degree of unsaturation of fatty acids and the participation of apolipoprotein E4 (ApoE4) in the onset of AD.

Zeolite and Neurodegenerative Diseases

Neurodegenerative diseases (NDs), characterized by progressive degeneration and death of neurons, are strongly related to aging, and the number of people with NDs will continue to rise. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common NDs, and the current treatments offer no cure. A growing body of research shows that AD and especially PD are intricately related to intestinal health and the gut microbiome and that both diseases can spread retrogradely from the gut to the brain. Zeolites are a large family of minerals built by [SiO4]4- and [AlO4]5- tetrahedrons joined by shared oxygen atoms and forming a three-dimensional microporous structure holding water molecules and ions. The most widespread and used zeolite is clinoptilolite, and additionally, mechanically activated clinoptilolites offer further improved beneficial effects. The current review describes and discusses the numerous positive effects of clinoptilolite and its forms on gut health and the gut microbiome, as well as their detoxifying, antioxidative, immunostimulatory, and anti-inflammatory effects, relevant to the treatment of NDs and especially AD and PD. The direct effects of clinoptilolite and its activated forms on AD pathology in vitro and in vivo are also reviewed, as well as the use of zeolites as biosensors and delivery systems related to PD.

Trace Elements in Alzheimer's Disease and Dementia: The Current State of Knowledge

Changes in trace element concentrations are being wildly considered when it comes to neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. This study aims to present the role that trace elements play in the central nervous system. Moreover, we reviewed the mechanisms involved in their neurotoxicity. Low zinc concentrations, as well as high levels of copper, manganese, and iron, activate the signalling pathways of the inflammatory, oxidative and nitrosative stress response. Neurodegeneration occurs due to the association between metals and proteins, which is then followed by aggregate formation, mitochondrial disorder, and, ultimately, cell death. In Alzheimer's disease, low Zn levels suppress the neurotoxicity induced by β-amyloid through the selective precipitation of aggregation intermediates. High concentrations of copper, iron and manganese cause the aggregation of intracellular α-synuclein, which results in synaptic dysfunction and axonal transport disruption. Parkinson's disease is caused by the accumulation of Fe in the midbrain dopaminergic nucleus, and the pathogenesis of multiple sclerosis derives from Zn deficiency, leading to an imbalance between T cell functions. Aluminium disturbs the homeostasis of other metals through a rise in the production of oxygen reactive forms, which then leads to cellular death. Selenium, in association with iron, plays a distinct role in the process of ferroptosis. Outlining the influence that metals have on oxidoreduction processes is crucial to recognising the pathophysiology of neurodegenerative diseases and may provide possible new methods for both their avoidance and therapy.

Mechanism of KAT2A regulation of H3K36ac in manganese-induced oxidative damage to mitochondria in the nervous system and intervention by curcumin

Excessive exposure to manganese in the environment or workplace is strongly linked to neurodegeneration and cognitive impairment, but the precise pathogenic mechanism and preventive measures are still not fully understood. The study aimed to investigate manganese -induced oxidative damage in the nervous system from an epigenetic perspective, focusing on the H3K36ac-dependent antioxidant pathway. Additionally, it sought to examine the potential of curcumin in preventing manganese-induced oxidative damage. Histopathology and transmission electron microscopy revealed that apoptosis and necrosis of neurons and mitochondrial ultrastructure damage were observed in the striatum of manganese-exposed rats. manganese suppressed the expression of mitochondrial antioxidant genes, leading to oxidative damage in the rats' striatum and SH-SY5Y cells. With higher doses of manganese, levels of histone acetyltransferase lysine acetyltransferase 2 A (KAT2A) expression and H3K36ac level decreased. ChIP-qPCR confirmed that H3K36ac enrichment in the promoter regions of antioxidant genes SOD2, PRDX3, and TXN2 was reduced in SH-SY5Y cells after manganese exposure, leading to decreased expression of these genes. Overexpression of KAT2A confirms that it attenuates manganese-induced mitochondrial oxidative damage by regulating H3K36ac levels, which in turn controls the expression of antioxidant genes SOD2, PRDX3, and TXN2 in the manganese-exposed cell model. Furthermore, curcumin might control H3K36ac levels by influencing KAT2A expression, boosting antioxidant genes expression, and reducing manganese-induced mitochondrial oxidative damage. In conclusion, the regulation of mitochondrial oxidative stress by histone acetylation may be an important mechanism of manganese-induced neurotoxicity. This regulation could be achieved by reducing the level of H3K36ac near the promoter region of mitochondrial-associated antioxidant genes via KAT2A. Curcumin mitigates manganese-induced oxidative damage in mitochondria and plays a crucial protective role in manganese-induced oxidative injury in the nervous system.

Dementia in the Ancient Greco-Roman World Was Minimally Mentioned

Background

The possibility that Alzheimer's disease and related dementias (ADRD) is a modern disease arises from the minimal mention of advanced cognitive decline by ancient Greeks and Romans, who were mainly concerned with the physical frailties of older ages.

Objective

Because standard medical histories of elderly health lacked mention of cognitive decline, we examined texts by Greek and Roman authors that mentioned memory loss and dementia.

Methods

Primary texts of Greco-Roman authors, 8th century BCE into the 3rd century CE, that mentioned cognitive decline were identified and critically evaluated. Secondary sources were excluded.

Results

No ancient account of cognitive loss is equivalent to modern clinical data. The term dementia was occasionally used in antiquity, but not invariably linked to old age. Ancient Greeks and Romans expected intellectual competence beyond age 60. While some memory loss was acknowledged, we found only four accounts of severe cognitive loss that might represent ADRD. The possibility of modest ADRD prevalence in ancient Greece and Rome is consistent with its low prevalence in the Tsimane of Bolivia. These contemporary Amerindians live under conditions of high mortality from frequent infections and minimal cardiovascular disease with physically demanding lives. Tsimane after age 60 had increased mild cognitive impairment; the few cases of dementia were not clinically consistent with AD.

Conclusions

The modern 'epidemic level' of advanced dementias was not described among ancient Greco-Roman elderly. The possible emergence of advanced ADRD in the Roman era may be associated with environmental factors of air pollution and increased exposure to lead. Further historical analysis may formulate critical hypotheses about the modernity of high ADRD prevalence.