Aluminium in Alzheimer's disease: are we still at a crossroad?

Neurotoxic effects of aluminum and manganese: From molecular to clinical effects

The existing data demonstrate that aluminum (Al) and manganese (Mn) possess neurotoxic effects upon overexposure due to induction of neuronal oxidative stress and apoptosis, synaptic dysfunction and neurotransmitter metabolism, neuroinflammation, and cytoskeletal pathology. However, systematic evidence regarding contribution of these metals to development of neurological diseases are lacking. Therefore, in this review we provide a summary of the existing data on contribution of Al and Mn exposure to brain diseases and its symptoms. Causal relations were demonstrated for development of parkinsonism upon exposure to high doses of Mn, whereas Al overload is considered the key contributor to dialysis encephalopathy. Certain studies demonstrate that Al and Mn overexposure is associated with neurodegenerative diseases including Alzheimer's and Parkinson's diseases, as well as neurodevelopmental disorders like autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Although laboratory studies demonstrate the potential contribution of Al and Mn to molecular pathogenesis of these diseases, clinical findings supporting the causal role of metals is these pathologies are yet insufficient. Therefore, estimation of the contribution of these metals to neurological disorders is essential for development of more effective early diagnostics and prevention of diseases under exposure to adverse neurological effects of Al and Mn compounds.

Detection of human health risks resulting from contamination of borehole drinking water with harmful volatile organic chemicals and potentially toxic elements around petroleum products dispensing outlets

Detection of human health risk caused by gasoline volatile organic chemicals and potentially toxic elements using an integrated approach to optimise data interpretation. The area is an urban centre with petroleum dispensing outlet and depending largely on borehole drinking water. Organic and toxic elements were analysed using gas chromatography and atomic absorption spectrophotometer, respectively. The study combined multivariate statistics and human health risk calculations. The water is moderately acidic causing low dispersion of toxic elements. Turbidity mean value of 15.64 NTU exceeded World Health Organization standard of 5NTU for potable water reflecting water pollution. Mean levels of benzene 2.20 mg/L and toluene 1.62 mg/L exceeded world standards for potable water. Benzene possesses higher daily intake levels in children than in adults through both ingestion and dermal contact. In children, benzene obtained hazard quotient ranging from 4.8 to 6.6 through dermal contact and 71.9-102.6 via ingestion pathway. Hazard risk of benzene ranged from 1.05 to 9.6 and 2.5-3.4 and toluene from 1.1-1.7 in children and adults. These values are greater than 1 reflecting non-carcinogenic risk. Cadmium, arsenic and antimony displayed non-carcinogenic risk in locations 2, 3, 4, 7, 9, 12, 14, 15 and 17. Carcinogenic risk of benzene and ethyl benzene in children via ingestion show that 1 in 0.0001 % and 1 in 0.01 % are susceptible to cancer in a lifetime of 70 years. Cadmium and arsenic has carcinogenic risk through ingestion pathway and dermal contact in children and adults. Incremental lifetime cancer risk of benzene, ethylbenzene, arsenic, lead and cadmium were above acceptable standard of 1.0E-06-1.0E-04 in children than adults through ingestion pathway than dermal contact. Buried petroleum storage tanks contributed to pollutants in the borehole water. Dissolution, dispersion and migration of benzene, toluene and ethyl benzene to boreholes adjacent to petroleum products outlets has harmful effects to water consumers. Integrating multivariate analysis, human health risks, odour hazard and risk index factor advances our understanding compared to previous works.

L-arginine mitigates choroid plexus changes in Alzheimer's disease rat model via oxidative/inflammatory burden and behavioral modulation

Aging is a risk factor for Alzheimer's disease (AD), leading to choroid plexus (CP) alterations. This study aimed to explore the possible therapeutic mechanisms of ARG on AD-induced CP changes. Sprague-Dawley rats were divided into 6 groups (n = 7 per group): adult, adult+ARG, aged, aged+ARG, aged+AD, and aged+AD+ARG groups. Evaluations were for Y-maze test, serum levels of oxidative/inflammatory markers, and serum and cerebrospinal fluid (CSF) markers of AD, histopathology, immunohistochemistry, and histomorphometry. The aged+AD group demonstrated a significant decline in maze test parameters, total antioxidant capacity (TAC), brain-derived neurotrophic factor (BDNF) levels, and vascular endothelial growth factor (VEGF) immunoexpression, while tumour necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), beta-amyloid (Aβ) levels and amyloid protein precursor (APP), and heat shock protein90 (HSP90) immunoexpressions were significantly increased. Sections of this group showed flat epitheliocytes, congested capillaries, connective tissue expansion, and degenerated endothelium. These parameters were modulated by ARG administration, via increased levels of TAC (1.37 vs 2.17 mmol/L), (p = 0.018) BDNF (serum: 48.50 vs 78.41; CSF: 4.07 vs 7.11 pg/ml) (p< 0.001), and VEGF (0.07 vs 0.26 OD) (p< 0.001), in addition to decreased levels of TNF-α (86.63 vs 41.39 pg/ml) (p< 0.001), IL-1β (96.04 vs 39.57 pg/ml) (p< 0.001), Aβ (serum: 67.40 vs 47.30; CSF: 189.26 vs 169.84 pg/ml) (p< 0.001), and HSP90 (0.54 vs 0.13 OD) (p< 0.001). In conclusion, ARG ameliorates the AD-associated CP changes, including histopathological, oxidative/inflammatory, and AD markers, and VEGF and HSP90 immunohistochemical alterations. Dietary ARG consumption is recommended to avoid AD progression in the elderly.

Embryonic exposure to aluminum chloride blocks the onset of spermatogenesis through disturbing the dynamics of testicular tight junctions via upregulating Slc25a5 in offspring

Studies have revealed neurotoxicity, hepatotoxicity, and developmental and reproductive toxicity in mice exposed to aluminum. However, relatively few studies have been conducted to clarify the mechanism underlying the impact of embryonic exposure to aluminum on the development of the male reproductive system in offspring. Pregnant mice were administered aluminum chloride (AlCl3) by gavage from day 12.5 of gestation until birth. Our findings demonstrated that embryonic exposure to AlCl3 disrupted testicular development and spermatogenesis by impairing testicular architecture, reducing sperm count, and upregulating the expression of tight junction (TJ) protein between Sertoli cells (SCs). Further in vitro studies revealed that treatment with AlCl3 stabilized TJ proteins Occludin and ZO-1 expression by inhibiting ERK signaling pathway activation, thereby upregulating Slc25a5 expression which induced ATP production leading to disruption of cytoskeletal protein homeostasis. Therefore, the study provided a new mechanistic insight into how AlCl3 exposure interfered with testicular development and spermatogenesis while suggesting that Slc25a5 might be a target affected by AlCl3 influencing cell metabolism.

ZBP1 mediates the progression of Alzheimer's disease via pyroptosis by regulating IRF3

Alzheimer's disease (AD) is one of the leading causes of death throughout the world. Z-DNA binding protein 1 (ZBP1), a DNA-related gene, is associated with inflammation, and its expression is altered in AD brain. We aimed to elucidate the exact role of ZBP1 in AD development and its potential regulatory mechanism. First, we constructed both in vivo and in vitro models of AD and investigated the ZBP1 expression profile. A loss-of-function assay was performed by transfecting lentivirus carrying ZBP1 short hairpin RNA (shRNA). By evaluating cell death, oxidative stress, inflammation response and pyroptosis, the function of ZBP1 was validated. Finally, the correlation between ZBP1 and interferon regulatory factor 3 (IRF3) was verified. We also performed rescue experiments to validate the crucial role of IRF3 in ZBP1-mediated AD progression. According to our results, ZBP1 was upregulated in AD rat tissue and AD neurons. Silencing ZBP1 dramatically decreased cell injury, oxidative stress and inflammation in AD neurons and improved the cognitive function of AD rats. Additionally, IRF3 expression and phosphorylation were significantly elevated during AD development and positively correlated with ZBP1. Taken together, silencing ZBP1 suppressed cell injury and pyroptosis of AD neurons and improved cognitive function of AD rats via inhibiting IRF3. These findings might provide a novel insight for AD target diagnosis and therapy.

Sub-Chronic Aluminum Exposure in Rats' Learning-Memory Capability and Hippocampal Histone H4 Acetylation Modification: Effects and Mechanisms

Aluminum has been found to be closely related to the pathogenesis of neurodegenerative diseases and damage learning and memory functions. Many changes in epigenetics may be one of the mechanisms of aluminum neurotoxicity. The purpose of this study is to further investigate the mechanism of action of sub-chronic aluminum exposure on learning memory and histone H4 acetylation modification in Wistar rats, and the correlation between learning memory impairment and histone H4 acetylation in aluminum-exposed rats. Rats in each dose group were given 0.0 g/L, 2.0 g/L, 4.0 g/L, and 8.0 g/L of AlCl3 distilled water daily for 12 weeks. The learning and memory ability of rats was measured by the Morris water maze test; the neuronal morphology of rat hippocampus was observed by Nissl staining and transmission electron microscope; real-time PCR, and Western blot were used to detect mRNA expression and protein content in hippocampus of rats. The results suggest that aluminum may affect the gene and protein expression of HAT1 and HDAC2, and then affect histone H4 and the acetylation of H4K12 (acH4K12), which may lead to learning and memory dysfunction in rats.

Influence of metal binding on the conformational landscape of neurofilament peptides

In order to understand the preferred modes of chelation in metal-binding peptides, quantum mechanical calculations can be used to compute energies, resulting in a hierarchy of binding affinities. These calculations often produce increasing stabilization energies the higher the coordination of the complex. However, as the coordination of a metal increases, the conformational freedom of the polypeptide chain is inevitably reduced, resulting in an entropic penalty. Estimating the magnitude of this penalty from the many different degrees of freedom of biomolecular systems is very challenging, and as a result this contribution to the free energy is often ignored. Here we explore this problem focusing on a family of phosphorylated neuropeptides that bind to aluminum. We find that there is a general negative correlation between both stabilization energy and entropy. Our results suggest that a subtle interplay between enthalpic and entropic forces will determine the population of the most favourable species. Additionally, we discuss the requirements for a possible "Metal Ion Hypothesis" based on our findings.

Characterization of just one atom using synchrotron X-rays

Since the discovery of X-rays by Roentgen in 1895, its use has been ubiquitous, from medical and environmental applications to materials sciences^1-5. X-ray characterization requires a large number of atoms and reducing the material quantity is a long-standing goal. Here we show that X-rays can be used to characterize the elemental and chemical state of just one atom. Using a specialized tip as a detector, X-ray-excited currents generated from an iron and a terbium atom coordinated to organic ligands are detected. The fingerprints of a single atom, the L_2,3 and M_4,5 absorption edge signals for iron and terbium, respectively, are clearly observed in the X-ray absorption spectra. The chemical states of these atoms are characterized by means of near-edge X-ray absorption signals, in which X-ray-excited resonance tunnelling (X-ERT) is dominant for the iron atom. The X-ray signal can be sensed only when the tip is located directly above the atom in extreme proximity, which confirms atomically localized detection in the tunnelling regime. Our work connects synchrotron X-rays with a quantum tunnelling process and opens future X-rays experiments for simultaneous characterizations of elemental and chemical properties of materials at the ultimate single-atom limit.

Role of aluminum exposure on Alzheimer's disease and related glycogen synthase kinase pathway

Aluminum (Al) is an environmentally abundant metal that is not essential for life. There is considerable evidence that Al as a neurotoxic xenobiotic may play a role in the pathogenesis of neurodegenerative diseases like Alzheimer's disease (AD). Exposure to aluminum has been shown to cause neuronal damage that resembles the symptoms of AD. In this review, we will summarize recent data about Al as the possible risk of incidence of AD. Then glycogen synthase kinase-3 beta (GSK3β) contributes to the hyperphosphorylation of Tau protein, the main component of neurofibrillary tangles, one of the hallmarks of AD as one of the mechanisms behind Al neurotoxicity will be covered. Overall, there is still a need for epidemiological studies and more in vivo and in vitro studies to determine the exact mechanisms of its neurotoxicity and the role of GSK3β in both Al toxic effect and AD.

Phytochemicals: A Promising Alternative for the Prevention of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that worsens with ageing and affects memory and cognitive function. Presently more than 55 million individuals are affected by AD all over the world, and it is a leading cause of death in old age. The main purpose of this paper is to review the phytochemical constituents of different plants that are used for the treatment of AD. A thorough and organized review of the existing literature was conducted, and the data under the different sections were found using a computerized bibliographic search through the use of databases such as PubMed, Web of Science, Google Scholar, Scopus, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS, and numerous other websites. Around 360 papers were screened, and, out of that, 258 papers were selected on the basis of keywords and relevant information that needed to be included in this review. A total of 55 plants belonging to different families have been reported to possess different bioactive compounds (galantamine, curcumin, silymarin, and many more) that play a significant role in the treatment of AD. These plants possess anti-inflammatory, antioxidant, anticholinesterase, and anti-amyloid properties and are safe for consumption. This paper focuses on the taxonomic details of the plants, the mode of action of their phytochemicals, their safety, future prospects, limitations, and sustainability criteria for the effective treatment of AD.

Neuroprotective effects of exogenous brain-derived neurotrophic factor on amyloid-beta 1-40-induced retinal degeneration

Amyloid-beta (Aβ)-related alterations, similar to those found in the brains of patients with Alzheimer's disease, have been observed in the retina of patients with glaucoma. Decreased levels of brain-derived neurotrophic factor (BDNF) are believed to be associated with the neurotoxic effects of Aβ peptide. To investigate the mechanism underlying the neuroprotective effects of BDNF on Aβ1-40-induced retinal injury in Sprague-Dawley rats, we treated rats by intravitreal administration of phosphate-buffered saline (control), Aβ1-40 (5 nM), or Aβ1-40 (5 nM) combined with BDNF (1 µg/mL). We found that intravitreal administration of Aβ1-40 induced retinal ganglion cell apoptosis. Fluoro-Gold staining showed a significantly lower number of retinal ganglion cells in the Aβ1-40 group than in the control and BDNF groups. In the Aβ1-40 group, low number of RGCs was associated with increased caspase-3 expression and reduced TrkB and ERK1/2 expression. BDNF abolished Aβ1-40-induced increase in the expression of caspase-3 at the gene and protein levels in the retina and upregulated TrkB and ERK1/2 expression. These findings suggest that treatment with BDNF prevents RGC apoptosis induced by Aβ1-40 by activating the BDNF-TrkB signaling pathway in rats.

The Impact of Long-Term Clinoptilolite Administration on the Concentration Profile of Metals in Rodent Organisms

Heavy metals are dangerous systemic toxicants that can induce multiple organ damage, primarily by inducing oxidative stress and mitochondrial damage. Clinoptilolite is a highly porous natural mineral with a magnificent capacity to eliminate metals from living organisms, mainly by ion-exchange and adsorption, thus providing detoxifying, antioxidant and anti-inflammatory medicinal effects. The in vivo efficiency and safety of the oral administration of clinoptilolite in its activated forms, tribomechanically activated zeolite (TMAZ) and Panaceo-Micro-Activated (PMA) zeolite, as well as the impact on the metallic biodistribution, was examined in healthy female rats. Concentration profiles of Al, As, Cd, Co, Pb, Ni and Sr were measured in rat blood, serum, femur, liver, kidney, small and large intestine, and brain using inductively coupled plasma mass spectrometry (ICP-MS) after a 12-week administration period. Our results point to a beneficial effect of clinoptilolite materials on the concentration profile of metals in female rats supplemented with the corresponding natural clinoptilolite materials, TMAZ and PMA zeolite. The observed decrease of measured toxicants in the kidney, femur, and small and large intestine after three months of oral intake occurred concomitantly with their most likely transient release into the bloodstream (serum) indicative of a detoxification process.

Biomechanical Behavior of Narrow Dental Implants Made with Aluminum- and Vanadium-Free Alloys: A Finite Element Analysis

Titanium (Ti) alloys used for narrow dental implants usually contain aluminum (Al) and vanadium (V) for improved resistance. However, those elements are linked to possible cytotoxic effects. Thus, this study evaluated the biomechanical behavior of narrow dental implants made with Al- and V-free Ti alloys by the finite element method. A virtual model of a partially edentulous maxilla received single implants (diameter: 2.7 and 2.9 mm; length: 10 mm) at the upper lateral incisor area, with respective abutments and porcelain-fused-to-metal crowns. Simulations were performed for each implant diameter and the following eight alloys (and elastic moduli): (1) Ti-6Al-4V (control; 110 GPa), (2) Ti-35Nb-5Sn-6Mo-3Zr (85 GPa), (3) Ti-13Nb-13Zr (77 GPa), (4) Ti-15Zr (113 GPa), (5) Ti-8Fe-5Ta (120 GPa), (6) Ti-26.88Fe-4Ta (175 GPa), (7) TNTZ-2Fe-0.4O (107 GPa), and (8) TNTZ-2Fe-0.7O (109 GPa). The implants received a labially directed total static load of 100 N at a 45° angle relative to their long axis. Parameters for analysis included the maximum and minimum principal stresses for bone, and von Mises equivalent stress for implants and abutments. Ti-26.88Fe-4Ta reaches the lowest maximum (57 MPa) and minimum (125 MPa) principal stress values, whereas Ti-35Nb-5Sn-6Mo-3Zr (183 MPa) and Ti-13Nb-13Zr (191 MPa) models result in the highest principal stresses (the 2.7 mm model surpasses the threshold for bone overload). Implant diameters affect von Mises stresses more than the constituent alloys. It can be concluded that the narrow implants made of the Ti-26.88Fe-4Ta alloy have the most favorable biomechanical behavior, mostly by mitigating stress on peri-implant bone.

Jellyfish as Food: A Narrative Review

Studies toward a sustainable future conducted by international organizations uniformly agree about having to change some of our present consumer behaviors. Regarding food, suggestions include eating locally farmed, less industrialized and renewable food to promote health and circularity, and limiting waste. Jellyfish are frequently sorted and discarded after being caught with fish in fishing nets and gear. In contrast, we propose utilizing this by-catch as food. This review discusses the economic value and sustainability of jellyfish, the technologies used to prepare them for human consumption, their nutritional profile and health impacts and, finally, consumer acceptability and sensory evaluation of jellyfish food products. This discussion is critical for promoting jellyfish as an important aquatic resource to support blue and circular economies.

Estropause, Sex Hormones and Metal Homeostasis in the Mouse Brain

Alterations in brain metal ion homeostasis have been reported with aging and are implicated in the pathogenesis of neurodegenerative diseases. To assess whether age-related changes in hypothalamic-pituitary-gonadal (HPG) hormones might be involved in modulating brain metal ion homeostasis, we treated 7.5-month intact, sham-ovariecomized and ovariectomized C57B6SJL mice with vehicle or leuprolide acetate (for 9-months) to differentiate between whether sex steroids or gonadotropins might modulate brain metal ion concentrations. Unlike other aging mammals, there was no increase in plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations following estropause in mice, suggesting there was sufficient residual production by the follicle depleted ovary, of sex steroids like estrogens and protein hormones like the inhibins, in order to suppress pituitary LH/FSH production. Castration on the other hand induced significant increases in circulating LH and FSH. Modulation of plasma sex steroid and gonadotropin levels did not significantly alter the concentrations of brain metals tested (Fe, Zn, Cu, Mn, Co, Ni, Al, Li), although there was a tendency for a decrease in all brain metals following ovariectomy (low estrogens and progesterone, high gonadotropins), a response that was reversed with leuprolide acetate treatment (low sex steroids, low gonadotropins). Brain Cu concentration was the only metal correlated with plasma LH (−0.37, n = 30, p < 0.05) and FSH (−0.42, n = 29, p < 0.01). This study demonstrates that sex hormones do not markedly alter brain metal ion homeostasis, unlike previously reported studies of circulating metal ion homeostasis. The role of gonadotropins in regulating metal ion homeostasis does however warrant further study.

Second Sphere Interactions in Amyloidogenic Diseases

Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.

Health Hazard Assessment Due to Slimming Medicinal Plant Intake

According to the World Health Organization (WHO), about 80% of people rely on medicinal plants for their primary health needs. Traditional medicine's principal benefits are their vast population knowledge, low severe adverse effects rate, low cost, and the lack of a medical prescription to use them. While obesity has become a global health issue, an increase in finding cheap and fast ways to lose weight escalates medicinal herbs' use for this purpose, both in dietary supplements or in teas. At the same time that Brazil aims to expand traditional medicine, reports regarding toxicology and poisoning put natural products' safety in check. Plants can accumulate heavy metals and metalloids leading to health risks; however, there is a lack of information on that matter, possibly due to a lack of international standardization regarding elemental contamination - this study aimed to determine metal and metalloid concentrations in slimming medicinal plants and their respective teas and evaluate their safety consumption. Metal and metalloid content were determined by inductively coupled plasma optical emission spectrometry (ICP OES). All plants and teas were within the set limits for tolerable upper intake level (UL), provisional tolerable daily maximum intake (PTDMI), and provisional tolerable weekly intake (PTWI). The hazard quotient index (HQ) was above 1 for almost all plants, and the Hibiscus sabdariffa tea regarding aluminum content. The arsenic level was above the Brazilian Pharmacopeia limit in natura plants demonstrating risk in their consumption. Some herbs also presented detection for elements with no safety limits set, such as lead, cadmium, and arsenic, which could mark as a red flag for consumption once their security intake is not precise yet.

Neurotoxic effects of aluminium exposure as a potential risk factor for Alzheimer's disease

Aluminium is one of the most widely distributed elements of the Earth's crust. Its routine use has resulted in excessive human exposure and due to the potential neurotoxic effects has attained a huge interest in recent years. Despite its ubiquitous abundance, aluminium has no crucial biological functions in the human body. Oxidative stress and neuroinflammatory effects are attributed to its neurotoxic manifestations implicated in Alzheimer's disease. In this review, we have discussed the neuroinflammatory and neurodegenerative events in the brain induced by aluminium exposure. We have highlighted the neurotoxic events caused by aluminium, such as oxidative stress, apoptosis, inflammatory events, calcium dyshomeostasis, Aβ deposition, and neurofibrillary tangle formation in the brain. In addition, the protective measures needed for prevention of aluminium-induced neuronal dysregulations have also been discussed.

Nanocurcumin, Promising Potential Protective Agent Against Histopathological Damage in the Cerebral Cortex of Mice Induced by Aluminum Chloride

&lt;b&gt;Background and Objective:&lt;/b&gt; Aluminum (Al) is widely used in many aspects of daily life, such as food packaging, cooking utensil components, food additives, cosmetics and water distillation. This study aimed to evaluate the protective role of nanocurcumin on the cerebral cortex of one and two-month-old mice exposed to 200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt., aluminium. &lt;b&gt;Materials and Methods:&lt;/b&gt; The Swiss Webster mice were used in this study. The control group only received sterile distilled water, the Al group was administered 200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt., of AlCl&lt;sub&gt;3&lt;/sub&gt; solution and the Al+Na Cur group was administered 200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt., AlCl&lt;sub&gt;3&lt;/sub&gt;+200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; nanocurcumin by intraperitoneal injection. The nanocurcumin was administered one hour after AlCl&lt;sub&gt;3 &lt;/sub&gt;exposure and then on days 0, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30. All the mice were anaesthetized and their brains were collected and fixed in a neutral formalin buffer solution for histological analysis. The paraffin method was used in this study. &lt;b&gt;Results:&lt;/b&gt; The death of granular neuron cells and karyolysis cells and the vacuolation of the pyramid cell layer of the cerebral cortex could be prevented by the intraperitoneal administration of nanocurcumin. The effect of nanocurcumin administration on the Al group at two months of age was more effective than on the Al group at one month of age. &lt;b&gt;Conclusion:&lt;/b&gt; Nanocurcumin can be a promising candidate protective agent against cerebral cortex changes after aluminium administration.

Water quality assessment, multivariate analysis and human health risks of heavy metals in eight major lakes in Kenya

This study evaluates water quality, concentrations and health risks of heavy metals (HMs) in eight major lakes in Kenya namely Naivasha, Elementaita, Nakuru, Baringo, Bogoria, Turkana, Victoria and Magadi. Water quality was assessed using water quality index (WQI) and pollution evaluation index (PEI), while human health risk associated with ingestion and dermal contact of HMs was assessed using hazard quotients (HQ) and hazard index (HI). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to deduce the probable sources of the HMs. The average concentration of aluminium (Al), molybdenum (Mo), manganese (Mn), nickel (Ni), arsenic (As), zinc (Zn), selenium (Se), lead (Pb), chromium (Cr), mercury (Hg), cobalt (Co) and cadmium (Cd) in the eight lakes was 824.6, 66.1, 58.9, 16.2, 8.40, 7.84, 6.91, 4.65, 2.66, 0.86, 0.78 and 0.46, respectively, all in μg/L. Al, Mn, As, and Mo were relatively high in Rift Valley lakes and exceeded the maximum permissible levels for drinking water. Notably, high HM concentrations were recorded at the entry points of rivers and areas with high human activities. Lake Magadi had the highest average WQI of 158.8 followed by lake Elementaita (128.4), Bogoria (79.5), Nakuru (73.3), Turkana (57.6), Victoria (52.3), Baringo (42.6) and Naivasha (25.5). Lake Magadi also had the highest average PEI of 40.0 followed by Elementaita (30.1), Bogoria (16.2), Nakuru (15.7), Victoria (10.8), Baringo (9.57), Turkana (9.53) and Naivasha (5.12). Based on WQI, Lake Naivasha water was excellent for drinking, Lake Victoria, Turkana, Baringo, Nakuru, and Bogoria had good water, but water from Lake Elementaita and Magadi was of poor quality. PEI classified the lakes as minimally polluted except Lake Magadi. Multivariate analysis concluded that Pb, Cr, Ni and Se had anthropogenic sources, mainly agricultural and urban runoff, but other HMs had natural influence. Although the HMs did not pose any health risks through dermal contact, HQingestion was >1 for adults and children consuming water from Lake Elementaita, Nakuru, Bogoria and Magadi due to non-carcinogenic risks associated with As, Zn and Mo. These results are important for formulating the necessary remediation policies to improve water quality in the eight lakes.

Risk assessment of potentially toxic elements in stream sediments around granite quarries, barite mines, and cultivation areas, Southeastern Nigeria

This study assessed the contamination of streams with potentially toxic elements (PTEs) in sediments around mining, quarrying, and cultivation areas in Akamkpa and environs Southeastern Nigeria. Analysis done using ICP MS technique shows that barium (Ba) and lead (Pb) recorded mean concentrations above their average shale content (ASC) in stream sediments. Chromium (Cr) exceeded Canadian Interim Sediment Quality Guideline (ISQG) and US Environmental Protection Agency (USEPA) screening benchmark value. Pb exceeded Canadian ISQG value but tallies with USEPA benchmark value. Pearson's correlation exhibited significant correlation (p < 0.01) of molybdenum (Mo) with copper (Cu) and Pb; Cu with Pb, vanadium (V), and Ba; V with Cu, Pb, iron (Fe), Ba, and beryllium (Be); and Fe with Be and V. Principal component (PC 1) consists of Pb, Mo, cobalt (Co), Cu, arsenic (As), Cr, V, and nickel (Ni) and showed significant correlation. Geo accumulation index (I-geo) values for Mo, Cu, V, Pb, Zn, Ni, Co, Mn, and Ba fall under unpolluted (0) to moderately polluted (1-2) classes. Maximum enrichment factor (EF) values show extremely high and significant enrichment of Ba and Pb in few locations. Co, Cr, Cu, Mn, and Zn possess maximum EF values classified as moderate enrichment. Ni, Mo, As, and V obtained maximum EF values classified as depleted to minimal enrichment. Modified pollution index (MPI) values showed high PTEs contamination in mostly cultivation locations. Single element potential ecological risk (EⁱR) mean values trend EⁱR (As) > EⁱR (Pb) > EⁱR (Co) > EⁱR (Cr) > EⁱR (Cu) > EⁱR (V) > EⁱR (Ni) > EⁱR (Zn). Comprehensive potential ecological risk (RI) shows medium risk "B" and strong risk "C" levels in few locations. The use of multiple pollution indices such as I-geo, EF, EⁱR, and RI in pollution assessment indicated similar trend of PTEs contamination of stream sediments. Levels of PTEs contamination are elevated in cultivation areas more than in granite quarrying and mining areas. This study serves as a benchmark for conducting suitable environmental management strategies to scientists in Nigeria and other parts of the world.

Retinal Dysfunction in Alzheimer's Disease and Implications for Biomarkers

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that manifests as cognitive deficits and memory decline, especially in old age. Several biomarkers have been developed to monitor AD progression. Given that the retina and brain share some similarities including features related to anatomical composition and neurological functions, the retina is closely associated with the progression of AD. Herein, we review the evidence of retinal dysfunction in AD, particularly at the early stage, together with the underlying molecular mechanisms. Furthermore, we compared the retinal pathologies of AD and other ophthalmological diseases and summarized potential retinal biomarkers measurable by existing technologies for detecting AD, providing insights for the future development of diagnostic tools.

Monitoring of Aluminum content in food and assessment of dietary exposure of residents in North China

Although the Chinese diet has become very abundant in the past 30 years, few people know that traditional Chinese diet is exposed to aluminium (Al). A total of 1232 samples were purchased during 2017-2019 and analysed for Al content with an inductively coupled plasma-mass spectrometry (ICP-MS) method. High Al levels were found in deep-fried dough sticks (mean 219 mg/kg), starch products (mean 84.5 mg/kg), and steam bread (mean 28.6 mg/kg). The average dietary Al exposure of residents in North China was 1.82 mg/kg bw/week, lower than the PTWI (provisional tolerable weekly intake). Deep-fried dough sticks (DFDS) are the main Al contributor in North China, providing 28.2% of the daily intake. The P95 dietary exposure to Al from DFDS was 2.3 mg/kg bw/week, exceeding the PTWI. Therefore, more attention should be paid to the health risk of exposure to Al from DFDS and starch products. Over-use of Al associated with food additives should be effectively controlled.

[The role of aluminum and lead in the development of Alzheimer's and Parkinson's diseases]

The article summarizes the data available in the literature on the toxic effects of aluminum and lead on the human brain and assesses the relationship of these effects to the etiopathogenesis of the most common neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. The accumulation of ions of these metals in the brain structures leads to chronic intoxication that is manifested by the morphological signs that are typical for Alzheimer's disease, such as deposits of β-amyloid and τ-protein mainly in the frontal and temporal regions of the cortex, and for Parkinson's disease, such as degeneration of dopamine neurons in the substantia nigra and their accumulation of α-synuclein. The most likely forms of participation of aluminum and lead ions in the mechanisms of neurodegeneration are the replacement of bivalent metal ions necessary for brain functioning, oxidative stress initiation, epigenetic modifications of histones, and increased expression of noncoding ribonucleic acids.

Neurodegenerative and Hepatorenal Disorders Induced Via Aluminum Chloride in Murine System: Impact of β-Secretase, MAPK, and KIM

Aluminum chloride (AlCl₃) is commonly used in daily life; meanwhile, it is the potential etiology of various neurodegenerative as well as hepatorenal diseases. Therefore, the present study was carried out to investigate the correlation between AlCl₃-induced biochemical alterations and the toxicity induced in various organs such as the brain, liver, and kidney. Male mice received AlCl₃ in an oral dose of 50 mg kg^-1 in addition to (50 mg) in drinking water for 2 weeks. Two weeks post-AlCl₃ intoxication, the brain, liver, and kidney biochemical indices were assessed via molecular and western blot analysis. The results are as follows: AlCl₃ intoxication induced a significant elevation in serum malondialdehyde in addition to a significant reduction in serum glutathione (GSH) and superoxide dismutase (SOD) levels. Brain β-secretase (tubulin-binding protein) and tau proteins which are responsible for the synthesis of β-amyloid protein that may interfere with neuronal communication in Alzheimer's disease (AD) were also upregulated; regarding hepatic function, AlCl₃ elevated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. Moreover, it upregulated hepatic mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) protein expressions as well as renal kidney-inducible molecule-1 (KIM-1) which indicated the deleterious effect of AlCl₃ on these organs. These results were confirmed by histopathological investigations. So, we hypothesize that acute AlCl₃ administration is responsible for oxidative cell damage that interferes with brain function inducing β-amyloid accumulation, Alzheimer's disease, and neurodegenerative damage as well as hepatorenal injuries.

Retinal changes in Alzheimer's disease- integrated prospects of imaging, functional and molecular advances

Alzheimer's Disease (AD) is a devastating neurodegenerative disorder of the brain, clinically characterised by cognitive deficits that gradually worsen over time. There is, at present, no established cure, or disease-modifying treatments for AD. As life expectancy increases globally, the number of individuals suffering from the disease is projected to increase substantially. Cumulative evidence indicates that AD neuropathological process is initiated several years, if not decades, before clinical signs are evident in patients, and diagnosis made. While several imaging, cognitive, CSF and blood-based biomarkers have been proposed for the early detection of AD; their sensitivity and specificity in the symptomatic stages is highly variable and it is difficult to justify their use in even earlier, pre-clinical stages of the disease. Research has identified potentially measurable functional, structural, metabolic and vascular changes in the retina during early stages of AD. Retina offers a distinctively accessible insight into brain pathology and current and developing ophthalmic technologies have provided us with the possibility of detecting and characterising subtle, disease-related changes. Recent human and animal model studies have further provided mechanistic insights into the biochemical pathways that are altered in the retina in disease, including amyloid and tau deposition. This information coupled with advances in molecular imaging has allowed attempts to monitor biochemical changes and protein aggregation pathology in the retina in AD. This review summarises the existing knowledge that informs our understanding of the impact of AD on the retina and highlights some of the gaps that need to be addressed. Future research will integrate molecular imaging innovation with functional and structural changes to enhance our knowledge of the AD pathophysiological mechanisms and establish the utility of monitoring retinal changes as a potential biomarker for AD.

Health concerns on provisional tolerable weekly intake of aluminium in children and adults from vegetables in Mandi-Gobindgarh (India)

Metallurgical industrial processes have been reported to cause higher aluminium (Al) exposure in humans through plant food intake due to higher soil Al content and acidification of soil resulted from industrial acid rains. Mandi-Gobindgarh is critically environmentally polluted steel industrial town in India in which Al is used for deoxidation, grain refining and alloying in steel production. The Al processing has been reported to release Al into the environment, and therefore present study was undertaken to investigate the dietary Al exposure in children and adult population of Mandi-Gobindgarh from consumption of vegetable food stuffs grown in the fields around steel industries. Thirteen vegetable types including fruit vegetables, root vegetables, and leafy vegetables (LVs) along with soil samples were collected from agricultural fields around M-site (Mandi-Gobindgarh industrial site) and C-site (control non-industrial site) and analysed for Al on WD-XRF. Higher vegetable Al content was reported due to higher soil Al content and higher acidic soil pH at M-site than C-site. Correlation coefficient data have shown positive correlation of plant/vegetable Al with soil Al whereas negative correlation with soil pH at both the sites. Hierarchical cluster analysis based on vegetable Al content and bioaccumulation factor depicted higher number of clusters of vegetables at M-site (3-clusters) than C-site (2-clusters). The hazard quotients for Al intake in children and adults were found less than one. However, the weekly dietary Al exposure data have shown more than provisional tolerable weekly intake of 2 mg/kgbw/week in them from two LVs (Spinach and Brassica) from M-site than C-site which increases health concerns in humans from Mandi-Gobindgarh.

Experimental modeling, optimization and comparison of coagulants for removal of metallic pollutants from wastewater

Wastewater treatment coagulation is one of the most important physicochemical operations used in industry. The adsorption capability of marigold leaf powder, tea waste and ferrous sulfate was investigated for domestic and tannery effluents. These adsorbents significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. Maximum decrease in all the attributes was observed for 10 g of adsorbents application. All the adsorbents significantly affected the physiochemical attributes of both wastewaters. Similarly, maximum adsorption potential was observed in case of tea waste powder. Maximum decrease in all physiochemical attributes such as pH (15%), EC (21%), turbidity (54%), total dissolved solids (TDS; 36%), total suspended solids (TSS; 43%), total hardness (TH; 52%), chloride contents (59%) and phosphate contents (60%) was observed with the application of 10 g of tea waste. Regarding the heavy metals, maximum decrease for cadmium (Cd; 47%), lead (Pb; 81%), arsenic (As; 44%), copper (Cu; 75%), iron (Fe; 49%), chromium (Cr; 68%) and zinc (Zn; 64%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was tea waste > marigold leaf powder > ferrous sulfate. However, for the wastewater, the maximum effect of adsorbents was observed in case of domestic wastewater as compared to the tannery water. Based on these data, it is suggested that tea waste has maximum adsorption potential for the remediation of wastewater.

Associations between Trace Elements and Cognitive Decline: An Exploratory 5-Year Follow-Up Study of an Elderly Cohort

Trace elements (TE) homeostasis is crucial in normal brain functioning. Although imbalances have the potential to exacerbate events leading neurodegenerative diseases, few studies have directly addressed the eventual relationships between TE levels in the human body and future cognitive status. The present study aimed to assess how different TE body-levels relate to cognitive decline. This exploratory research included a study-group (RES) of 20 elderly individuals living in two Portuguese geographical areas of interest (Estarreja; Mértola), as well as a 20 subjects neuropsychological control-group (CTR). Participants were neuropsychologically assessed through the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) and the RES group was biomonitored for TE through fingernail analysis. After 5 years, the cognitive assessments were repeated. Analyses of the RES neuropsychological data showed an average decrease of 6.5 and 5.27 points in MMSE and MoCA, respectively, but TE contents in fingernails were generally within the referenced values for non-exposed individuals. Higher levels of Nickel and Selenium significantly predicted lesser cognitive decline within 5 years. Such preliminary results evidence an association between higher contents of these TE and higher cognitive scores at follow-up, suggesting their contribution to the maintenance of cognitive abilities. Future expansion of the present study is needed in order to comprehensively assess the potential benefits of these TE.

Recent Developments in Magnesium Metal-Matrix Composites for Biomedical Applications: A Review

Recently, there is a growing interest in developing magnesium (Mg) based degradable biomaterial. Although corrosion is a concern for Mg, other physical properties, such as low density and Young's modulus, combined with good biocompatibility, lead to significant research and development in this area. To address the issues of corrosion and low yield strength of pure Mg, several approaches have been adopted, such as, composite preparation with suitable bioactive reinforcements, alloying, or surface modifications. This review specifically focuses on recent developments in Mg-based metal matrix composites (MMCs) for biomedical applications. Much effort has gone into finding suitable bioactive, bioresorbable reinforcements and processing techniques that can improve upon existing materials. In summary, this review provides a comprehensive overview of existing Mg-based composite preparation and their mechanical and corrosion properties and biological responses and future perspectives on the development of Mg-based composite biomaterials.

Theoretical characterization of Al(III) binding to KSPVPKSPVEEKG: Insights into the propensity of aluminum to interact with key sequences for neurofilament formation

Classical molecular dynamic simulations and density functional theory are used to unveil the interaction of aluminum with various phosphorylated derivatives of the fragment KSPVPKSPVEEKG (NF13), a major multiphosphorylation domain of human neurofilament medium (NFM). Our calculations reveal the rich coordination chemistry of the resultant structures with a clear tendency of aluminum to form multidentate structures, acting as a bridging agent between different sidechains and altering the local secondary structure around the binding site. Our evaluation of binding energies allows us to determine that phosphorylation has an increase in the affinity of these peptides towards aluminum, although the interaction is not as strong as well-known chelators of aluminum in biological systems. Finally, the presence of hydroxides in the first solvation layer has a clear damping effect on the binding affinities. Our results help in elucidating the potential structures than can be formed between this exogenous neurotoxic metal and key sequences for the formation of neurofilament tangles, which are behind of some of the most important degenerative diseases.

A Systematic Review of Risk Assessment Associated with Jellyfish Consumption as a Potential Novel Food

FAO (Food and Agriculture Organization of the United Nations) predicted that the world's population will reach over 9 billion in 2050. This condition will require an increase of the global food production by 60%. Technology and scientific research in the near future will soon be oriented towards optimizing the limited existing resources, reducing waste, and improving the consumption of sustainable new foods. Jellyfish could be a valid alternative among novel food. The purpose of this systematic review was to assess microbiological, chemical, physical, and allergenic risks associated with jellyfish consumption. Four research strings have been used to assess evidences about these risks. PRISMA (Preferred Reporting Item for Systematic Reviews and Meta-analysis) guidelines were applied. Finally, 14 articles were found. Results showed a good level of health safety for jellyfish consumption in terms of its allergenic and microbiological risks. No evidence was found about physical risks. As regards chemical safety, it should be fundamental to carry out a constant monitoring of the water where jellyfish are captured or bred. Periodic checks will be necessary on the finished product, such as the analysis of the aluminum content commonly used during the manufacturing process. The number of publications found was rather small, and further investigation will be necessary to enforce the knowledge on jellyfish consumption by humans.

The interaction of aluminum with catecholamine-based neurotransmitters: can the formation of these species be considered a potential risk factor for neurodegenerative diseases?

The potential neurotoxic role of Al(iii) and its proposed link with the insurgence of Alzheimer's Disease (AD) have attracted increasing interest towards the determination of the nature of bioligands that are propitious to interact with aluminum. Among them, catecholamine-based neurotransmitters have been proposed to be sensitive to the presence of this non-essential metal ion in the brain. In the present work, we characterize several aluminum-catecholamine complexes in various stoichiometries, determining their structure and thermodynamics of formation. For this purpose, we apply a recently validated computational protocol with results that show a remarkably good agreement with the available experimental data. In particular, we employ Density Functional Theory (DFT) in conjunction with continuum solvation models to calculate complexation energies of aluminum for a set of four important catecholamines: l-DOPA, dopamine, noradrenaline and adrenaline. In addition, by means of the Quantum Theory of Atoms in Molecules (QTAIM) and Energy Decomposition Analysis (EDA) we assessed the nature of the Al-ligand interactions, finding mainly ionic bonds with an important degree of covalent character. Our results point at the possibility of the formation of aluminum-catecholamine complexes with favorable formation energies, even when proton/aluminum competition is taken into account. Indeed, we found that these catecholamines are better aluminum binders than catechol at physiological pH, because of the electron withdrawing effect of the positively-charged amine that decreases their deprotonation penalty with respect to catechol. However, overall, our results show that, in an open biological environment, the formation of Al-catecholamine complexes is not thermodynamically competitive when compared with the formation of other aluminum species in solution such as Al-hydroxide, or when considering other endogenous/exogenous Al(iii) ligands such as citrate, deferiprone and EDTA. In summary, we rule out the possibility, suggested by some authors, that the formation of Al-catecholamine complexes in solution might be behind some of the toxic roles attributed to aluminum in the brain. An up-to-date view of the catecholamine biosynthesis pathway with sites of aluminum interference (according to the current literature) is presented. Alternative mechanisms that might explain the deleterious effects of this metal on the catecholamine route are thoroughly discussed, and new hypotheses that should be investigated in future are proposed.

Removal efficiency of Gram-positive and Gram-negative bacteria using a natural coagulant during coagulation, flocculation, and sedimentation processes

Staphylococcus sp. as Gram-positive and Escherichia coli as Gram-negative are bacterial pathogens and can cause primary bloodstream infections and food poisoning. Coagulation, flocculation, and sedimentation processes could be a reliable treatment for bacterial removal because suspended, colloidal, and soluble particles can be removed. Chemical coagulants, such as alum, are commonly used. However, these chemical coagulants are not environmentally friendly. This present study evaluated the effectiveness of coagulation, flocculation, and sedimentation processes for removing Staphylococcus sp. and E. coli using diatomite with standard jar test equipment at different pH values. Staphylococcus sp. demonstrated 85.61% and 77.23% significant removal in diatomite and alum, respectively, at pH 5. At pH 7, the removal efficiency decreased to 79.41% and 64.13% for Staphylococcus sp. and E. coli, respectively. At pH 9, there was a decrease in Staphylococcus sp. after adding diatomite or alum compared with that of E. coli. The different removal efficiencies of the Gram-positive and Gram-negative bacteria could be owing to the membrane composition and different structures in the bacteria. This study indicates that diatomite has higher efficiency in removing bacteria at pH 5 and can be considered as a potential coagulant to replace alum for removing bacteria by the coagulation process.

Double-edged effects of aluminium ions on amyloid fibrillation of hen egg-white lysozyme

Elucidating the effects of Al(III) ions on amyloid fibrillation is important to understand the association between metal ions and Alzheimer's disease. Here, Raman spectroscopy was applied to investigate amyloid fibrillation of hen egg-white lysozymes during thermal incubation with Al(III) ions or acids, combined with atomic force microscopy and thioflavin T fluorescence assays. Kinetics of conformational changes in lysozymes were assessed by monitoring six characteristic Raman spectral markers. The peak of Phe residues at 1003 cm^-1 and two bands of Trp residues at 759 cm^-1 and 1340-1360 cm^-1 corresponded to the lysozyme tertiary structure, whereas two NC_αC stretching vibrations at 899 cm^-1 and 935 cm^-1 and an amide I band were associated with the lysozyme skeleton. There may be a four-stage transformation mechanism underlying the kinetics of amyloid fibrillation of lysozymes with the thermal/Al(III) treatment. Comparison of kinetics under thermal/Al(III) and thermal/acid conditions revealed double-edged roles of Al(III) ions in amyloid fibrillation of lysozymes. Specifically, in addition to postponing α-helix degradation, Al(III) ions accelerated conformational transformations from α-helices to organized β-sheets. The present investigation sheds light on the controversial effects of Al(III) ions on amyloid fibrillation of lysozymes.

Histomorphometric evaluation of seminiferous tubules and stereological assessment of germ cells in testes following administration of aqueous leaf-extract of Lawsonia inermis on aluminium-induced oxidative stress in adult Wistar rats

OBJECTIVES

This study aimed to investigate the 'Cytoprotective effect of Lawsonia inermis aqueous leaf-extract on aluminium-induced Oxidative stress in Histomorphometric of the Seminiferous tubule and Stereology of Germ Cells of adult male Wistar rats', assessing its effect on the Histomorphometry of the Seminiferous tubule and Stereology of Germ Cells.

METHODS

Thirty-five adult male Wistar rats, weighing between 100-196g, and fifteen mice of the same weight range were used. Lawsonia inermis extracts and aluminum chloride (AlCl₃) were administered for a period of three (3) weeks, with Five (5) rats per group. Group 1 (control), received rat pellets and distilled water. Group 2 received 60mg/kg/d aqueous extract. Group 3 received 0.5mg/kg/d of AlCl₃. Group 4 received 0.5mg/kg/d of AlCl₃ and 60mg/kg/d of aqueous extract orally. Group 5 received 0.5mg/kg/d of AlCl₃ and 75mg/kg/d of aqueous extract orally. Group 6 received 0.5mg/kg/d of AlCl₃ and 100mg/kg/d of aqueous extract orally. Group 7 received 0.5mg/k/d of AlCl₃ and 5mg/Kg/d of ascorbic acid orally. Twenty-four hours after the last administration, the animals were weighed, sedated with chloroform and blood was collected. The testes were removed and weighed.

RESULTS

There were statistically significant changes in the percentage of seminiferous tubular and seminiferous ductal diameter within the experimental animals in all the groups (p<0.05). Stereological findings revealed increase in spermatogonia, primary spermatocytes, round Spermatids and elongated spematids, spermatozoa, Sertoli cells population of the control rats while the rats given 0.5mg of aluminum chloride per kg of body weight had the lowest value (p<0.05).

CONCLUSION

In this study, we demonstrated the affected histomorphometry of the seminiferous tubule and stereology of germ cells in testes, where stress impacts were most felt and subsequently translated into drastic reproductive dysfunction and distortion of spermatogenesis.

Does phosphorylation increase the binding affinity of aluminum? A computational study on the aluminum interaction with serine and O-phosphoserine

Several toxic effects arise from aluminum's presence in living systems, one of these effects is to alter the natural role of enzymes and non-enzyme proteins. Aluminum promotes the hyperphosphorylation of normal proteins. In order to assess the aluminum-binding abilities of phosphorylated proteins and peptides, the interaction of aluminum at different pH with serine and phosphoserine is studied by a Density Functional Theory study, combined with polarizable continuum models to account for bulk solvent effects, and the electronic structure of selected complexes are analyzed by Quantum Theory of "Atoms in Molecules". Our results confirm the high ability of aluminum to bind polypeptides as the pH lowers. Moreover, the phosphorylation of the building blocks increases the affinity for aluminum, in particular at physiological pH. Finally, aluminum shows a tendency to be chelated forming different size rings.

'Evolutionary medicine' perspectives on Alzheimer's Disease: Review and new directions

Evolution by natural selection eliminates maladaptive traits from a species, and yet Alzheimer's Disease (AD) persists with rapidly increasing prevalence globally. This apparent paradox begs an explanation within the framework of evolutionary sciences. Here, I summarize and critique previously proposed theories to explain human susceptibility to AD, grouped into 8 distinct hypotheses based on the concepts of novel extension of the lifespan; lack of selective pressure during the post-reproductive phase; antagonistic pleiotropy; rapid brain evolution; delayed neuropathy by selection for grandmothering; novel alleles selected to delay neuropathy; by-product of selection against cardiovascular disease; and thrifty genotype. Subsequently, I describe a new hypothesis inspired by the concept of mismatched environments. Many of the factors that enhance AD risk today may have been absent or functioned differently before the modern era, potentially making AD a less common affliction for age-matched individuals before industrialization and for the majority of human history. Future research is needed to further explore whether changes in environments and lifestyles across human history moderate risk factors and susceptibility to AD.

Human predisposition to cognitive impairment and its relation with environmental exposure to potentially toxic elements

New lines of evidence suggest that less than 10% of neurodegenerative diseases have a strict genetic aetiology and other factors may be prevalent. Environmental exposures to potentially toxic elements appear to be a risk factor for Parkinson's, Alzheimer's and sclerosis diseases. This study proposes a multidisciplinary approach combining neurosciences, psychology and environmental sciences while integrating socio-economic, neuropsychological, environmental and health data. We present the preliminary results of a neuropsychological assessment carried out in elderly residents of the industrial city of Estarreja. A battery of cognitive tests and a personal questionnaire were administered to the participants. Multivariate analysis and multiple linear regression analysis were used to identify potential relationships between the cognitive status of the participants and environmental exposure to potentially toxic elements. The results suggest a relationship between urinary PTEs levels and the incidence of cognitive disorders. They also point towards water consumption habits and profession as relevant factors of exposure. Linear regression models show that aluminium (R ² = 38%), cadmium (R ² = 11%) and zinc (R ² = 6%) are good predictors of the scores of the Mini-Mental State Examination cognitive test. Median contents (µg/l) in groundwater are above admissible levels for drinking water for aluminium (371), iron (860), manganese (250), and zinc (305). While the World Health Organization does not provide health-based reference values for aluminium, results obtained from this study suggest that it may have an important role in the cognitive status of the elderly. Urine proved to be a suitable biomarker of exposure both to elements with low and high excretion rates.

Accumulation Patterns of Sub-chronic Aluminum Toxicity Model After Gastrointestinal Administration in Rats

Although aluminum chronic neurotoxicity is well documented, there are no well-established experimental protocols of Al exposure. In the current study, toxic effects of sub-chronic Al exposure have been evaluated in outbreed male rats (gastrointestinal administration). Forty animals were used: 10 were administered with AlCl₃ water solution (2 mg/kg Al per day) for 1 month, 10 received the same concentration of AlCl₃ for 3 month, and 20 (10 per observation period) saline as control. After 30 and 90 days, the animals underwent behavioral tests: open field, passive avoidance, extrapolation escape task, and grip strength. At the end of the study, the blood, liver, kidney, and brain were excised for analytical and morphological studies. The Al content was measured by inductively coupled plasma mass-spectrometry. Essential trace elements-Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, and Zn-were measured in whole blood samples. Although no morphological changes were observed in the brain, liver, or kidney for both exposure terms, dose-dependent Al accumulation and behavioral differences (increased locomotor activity after 30 days) between treatment and control groups were indicated. Moreover, for 30 days exposure, strong positive correlation between Al content in the brain and blood for individual animals was established, which surprisingly disappeared by the third month. This may indicate neural barrier adaptation to the Al exposure or the saturation of Al transport into the brain. Notably, we could not see a clear neurodegeneration process after rather prolonged sub-chronic Al exposure, so probably longer exposure periods are required.

Aluminium (Al) speciation in serum and urine after subcutaneous venom immunotherapy with Al as adjuvant

BACKGROUND

Aluminium is associated with disorders and is the commonly used vaccine adjuvant. Understanding the mechanisms of how Al is transported, metabolized or of its toxicity depends on the knowledge of Al-interactions with bioligands, i.e. Al-species. Al-speciation in serum is difficult because of low concentration and the risk of exogenous Al contamination. Furthermore, Al-measurements may be hampered according to various interferences. This study aims for developing quality controlled protocols for reliable Al- and Al-species determination and for investigating probable differences in Al (-speciation) after Al-containing subcutaneous immunotherapy (SIT).

METHODS

Sample donors were recruited either for the control group ("class-0", they never had been treated with SIT containing an Al-depot extract) or for the SIT-group ("class-1", they previously had been treated with SIT for insect venom allergy with an Al-depot extract). Blood was drawn for medical reasons and serum prepared. Additionally, some sample donors collected 24-h-urine. They had been informed (and they consented) about the scientific use of their samples. The study was approved by the ethic committee of the "Medical Association Westphalia-Lippe" and of the University of Münster, evaluating the study positively (No. 2013-667-f-S). We applied quality controlled sample preparation and interference-free Al detection by ICP sectorfield-mass spectrometry. Al-species were analysed using size-exclusion-chromatography-ICP-qMS.

FINDINGS

Al-concentrations or speciation in urine samples showed no differences between class-0 and class-1. Al-citrate was the main uric Al-species. In serum elevated Al-concentrations were found for both classes, with class-1 samples being significantly higher than class-0 (p = 0.041), but class-0 samples being approximately 10-fold too high compared to reference values from non-exposed persons. We identified gel-monovettes as contamination source. In contamination-free samples from HNO₃-prewashed gel-free monovettes (n = 27) there was no difference in the serum Al concentration between the two patient groups (p = 0.669) INTERPRETATION: Thorough cleaning of sample preparation ware and use of gel-free monovettes is decisive for an accurate Al analysis in serum. Without these steps, wrong analysis and wrong conclusions are likely. We conclude that gel-monovettes are unsuitable for blood sampling with subsequent Al-analysis. Whether Al in serum is elevated after SIT treatment containing an Al-depot extract, or not, remains inconclusive as the non-contaminated sample size was small.

Metal concentrations in traditional and herbal teas and their potential risks to human health

Food and beverage consumption is an important route for human exposure to metals. Traditional tea (Camellia sinensis) is a widely-consumed beverage, which may contain toxic metals. This study determined total and infusion concentrations of 5 metals including Al, As, Cd, Cr, and Pb in 47 traditional and herbal teas from 13 countries and assessed their potential risks to human health. The data showed that herbal teas exhibited higher As (0.26mgkg^-1), Cd (0.19mgkg^-1) and Pb (2.32mgkg^-1) than traditional teas. Black tea from India had high Cr at 31mgkg^-1 while white tea from China had low Cr at 0.39mgkg^-1. Arsenic, Cd and Pb did not exceed the WHO limit for medicinal plants excluding one herbal tea with 1.1mgkg^-1 As and 26.4mgkg^-1 Pb. However, Cr in 47% herbal teas and 73% traditional teas exceeded the Canada limit of 2mgkg^-1. Metal concentrations in tea infusions were below the MCL for drinking water except for Al. Total Al and its infusion was lower in herbal teas (47-1745mgkg^-1 and 0.09-3.95mgL^-1) than traditional teas (50.3-2517mgkg^-1 and 0.02-7.51mgL^-1), with 0.9-22% and 4-49% of the Al being soluble in infusion. The Al concentrations in infusion in all black tea and 83, 75 and 25% of the green, oolong and herbal teas exceeded the secondary MCL for drinking water at 0.2mgL^-1. However, the weekly intake of Al from drinking tea (0.001-0.39 and 0.003-0.56mgkg^-1 for children and adults) was lower than the provisional tolerable weekly intake for Al at 1.0mgkg^-1. Our data showed that it is important to consider metal intake from tea consumptions, especially for Cr and Al in heavy tea drinkers.