Effects of lead exposure on brain glucose metabolism and insulin signaling pathway in the hippocampus of rats

Empagliflozin and memantine combination ameliorates cognitive impairment in scopolamine + heavy metal mixture-induced Alzheimer's disease in rats: role of AMPK/mTOR, BDNF, BACE-1, neuroinflammation, and oxidative stress

One of the major consequences of diabetes mellitus that has gained attention due to its rising incidence is cognitive impairment. Recent research suggested that sodium-glucose cotransporter-2 (SGLT-2) inhibitors can mitigate memory impairment linked to Alzheimer's disease and are now being explored for their cognitive benefits. However, their mechanisms were not thoroughly studied. This research investigates the hypothesis of the neuroprotective effect of empagliflozin administration against scopolamine-heavy metal mixture (SCO + HMM)-treated Alzheimer's rat models in comparison with memantine as a reference drug and the impact of their combination. Yet, the neuroprotective effects of memantine and empagliflozin combination against cognitive impairment have not been previously explored. This study employed adult male albino rats categorized into five groups. The impact of empagliflozin, memantine, and their concomitant administration on cognitive performance was assessed in a scopolamine and heavy metal mixture-treated Alzheimer's disease model in rats. The assessment of rats' cognitive behavior, memory, and spatial learning was conducted, followed by an evaluation of hippocampal brain-derived neurotrophic factor (BDNF), beta-secretase (BACE-1), oxidative stress (OS), and inflammatory marker activity. And, a western blot analysis was conducted to detect phosphorylated 5' AMP-activated protein kinase (p-AMPK), phosphorylated mammalian target of rapamycin (p-mTOR), and heme oxygenase-1 (HO-1). Hippocampal and cerebellar histopathology were thoroughly examined, in addition to the expressions of amyloid β (Aβ). The current data demonstrate the involvement of the pAMPK/mTOR/HO-1 signaling pathway in empagliflozin neuroprotection against SCO + HMM-induced AD. In addition, it reduces AD hallmarks (Aβ and BACE1), neuro-inflammation, and oxidative stress sequelae, and enhances neurogenesis and synaptic density via BDNF. This study proposes that EMPA, especially when co-administered with other conventional anti-Alzheimer therapy, may be formulated into an innovative therapeutic strategy for the enhancement of cognitive impairments associated with neurodegenerative disorders.

Lead exposure disrupts cytoskeletal arrangement and perturbs glucose metabolism in nerve cells through activation of the RhoA/ROCK signaling pathway

Lead (Pb) is a heavy metal environmental pollutant with strong biological toxicity. Our previous study suggested that Pb may impair learning and memory by disrupting cytoskeletal structure and inhibiting the expression of synaptic plasticity-related proteins in mice. However, the exact mechanism of Pb-induced cytoskeletal damage remains unclear. In this study, Neuro-2a cells and Kunming mice were used to explore the neurotoxic mechanism of Pb. The actin dynamics were observed via laser confocal microscopy. The ATP levels and ATPase activity in Neuro-2a cells was measured. In addition, the mRNA and protein expression levels of RhoA/ROCK/Cofilin signaling pathway in brain tissues and Neuro-2a cells was measured, and the mRNA expression levels of glucose metabolism rate-limiting enzymes were detected. Our results showed that Pb induces nerve cell damage and cytoskeletal abnormalities. Western blot and qRT-PCR analyses revealed that Pb activated the RhoA/ROCK/Cofilin signaling pathway. Additionally, ATPase activity significantly decreased following Pb treatment, whereas ATP levels markedly increased in the 50 μM Pb group. In addition, Pb disrupts brain glucose metabolism through affect the transcription of rate-limiting enzymes of glucose metabolism. Overall, these findings suggest that Pb activates the RhoA/ROCK/Cofilin signaling pathway, leading to cytoskeletal damage. Moreover, Pb exposure alters glucose metabolism enzyme activity and ATP production, disrupting the balance between F-actin and G-actin and ultimately affecting neuronal structure and function. These results may provide a better understanding of lead-induced nerve damage.

Avicularin Attenuated Lead-Induced Ferroptosis, Neuroinflammation, and Memory Impairment in Mice

Lead (Pb) is a common environmental neurotoxicant that results in abnormal neurobehavior and impaired memory. Avicularin (AVL), the main dietary flavonoid found in several plants and fruits, exhibits neuroprotective and hepatoprotective properties. In the present study, the effects of AVL on Pb-induced neurotoxicity were evaluated using ICR mice to investigate the molecular mechanisms behind its protective effects. Our study has demonstrated that AVL treatment significantly ameliorated memory impairment induced by lead (Pb). Furthermore, AVL mitigated Pb-triggered neuroinflammation, ferroptosis, and oxidative stress. The inhibition of Pb-induced oxidative stress in the brain by AVL was evidenced by the reduction in malondialdehyde (MDA) levels and the enhancement of glutathione (GSH) and glutathione peroxidase (GPx) activities. Additionally, in the context of lead-induced neurotoxicity, AVL mitigated ferroptosis by increasing the expression of GPX4 and reducing ferrous iron levels (Fe2+). AVL increased the activities of glycogenolysis rate-limiting enzymes HK, PK, and PYG. Additionally, AVL downregulated TNF-α and IL-1β expression while concurrently enhancing the activations of AMPK, Nrf2, HO-1, NQO1, PSD-95, SNAP-25, CaMKII, and CREB in the brains of mice. The findings from this study suggest that AVL mitigates the memory impairment induced by Pb, which is associated with the AMPK/Nrf2 pathway and ferroptosis.

Childhood blood-lead level predicts lower general, non-selective hippocampal subfield volumes in midlife

Millions of adults and children are exposed to high levels of lead, a neurotoxicant, each year. Recent evidence suggests that lead exposure may precipitate neurodegeneration, particularly if the exposure occurs early or late in life, with unique alterations to the structure or function of specific subfields of the hippocampus, a region involved in memory and Alzheimer's disease. It has been proposed that specific hippocampal subfields may thus be useful biomarkers for lead-associated neurological disease. We turned to a population-representative New Zealand birth cohort where the extent of lead exposure was not confounded by social class (the Dunedin Study; born 1972-1973 and followed to age 45) to test the hypothesis that early life lead exposure (blood-lead level at age 11 years) is associated with smaller MRI-assessed gray matter volumes of specific subfields of the hippocampus at age 45 years. Among the 508 Dunedin Study members with childhood lead data and adult MRI data passing quality control (93.9 % of those with lead data who attended the age-45 assessment wave, 240[47.2 %] female), childhood blood-lead levels ranged from 4 to 31 µg/dL (M[SD]=10.9[4.6]). Total hippocampal volumes were lower among adults with higher childhood blood-lead levels (b=-102.6 mm3 per 5 ug/dL-unit greater blood-lead level, 95 %CI: -175.4 to -29.7, p=.006, β=-.11), as were all volumes of the 24 hemisphere-specific subfields of the hippocampus. Of these 24 subfields, 20 demonstrated negative lead-associations greater than β=-.05 in size, 14 were statistically significant after adjustment for multiple comparisons (pFDR<.05), and 9 remained significant after adjustment for potential confounders and multiple comparisons. Children exposed to lead demonstrate smaller volumes across all subfields of the hippocampus in midlife. The hypothesis that lead selectively impairs specific subfields of the hippocampus, or that specific subfields may be markers for lead-associated neurological disease, requires further evaluation.

Glutamine Defended the Kidneys Versus Lead Intoxication Via Elevating Endogenous Antioxidants, Reducing Inflammation and Carbonyl Stress, as well as Improving Insulin Resistance and Dyslipidemia

Kidneys are primarily sensitive to lead (Pb) poisoning due to their cardinal role in lead excretion. Then, we studied the effect of glutamine (Gln) on lead nephrotoxicity in rats by assessing the histopathological and biochemical parameters (the renal NF-kβ expression, metabolic profile, oxidative stress, inflammatory markers, methylglyoxal (MGO), and glyoxalase-I activity). Forty rats were allotted into four groups (ten rats in each): normal (N), Gln-treated N, Pb intoxication (Pbi), and Gln-treated Pbi. The treated groups took 0.1% Gln in drinking water for 1 month. To motivate lead poisoning, rats gained 50 mg/l lead acetate in drinking water for 1 month. Oxidative stress indices (total glutathione, its reduced and oxidized forms, their ratios, advanced protein oxidation products, malondialdehyde, and ferric ion reducing power) and inflammatory markers (renal nuclear factor-kβ expression, interleukin 1β level, and myeloperoxidase activity) were measured. Furthermore, metabolic profile (fasting blood sugar, insulin, insulin resistance, lipid profile, and atherogenic index) and renal dysfunction parameters were determined. Pb-induced renal histopathological alterations were investigated by a pathologist. In the kidney of Pbi rats, the glomerulus was damaged. Gln prevented kidney damage and reduced kidney dysfunction parameters. In addition, Gln decreased oxidative stress and inflammation in sera and kidney homogenates. In addition, it improved insulin resistance, dyslipidemia, and carbonyl stress (p < 0.001). Gln guarded the kidneys versus lead intoxication by improving insulin resistance and dyslipidemia, elevating antioxidant markers, and diminishing inflammation and carbonyl stress.

A high fat diet potentiates neonatal iron overload-induced memory impairments in rats

PURPOSE

The present study aimed at evaluating possible synergistic effects between two risk factors for cognitive decline and neurodegenerative disorders, i.e. iron overload and exposure to a hypercaloric/hyperlipidic diet, on cognition, insulin resistance, and hippocampal GLUT1, GLUT3, Insr mRNA expression, and AKT phosporylation.

METHODS

Male Wistar rats were treated with iron (30 mg/kg carbonyl iron) or vehicle (5% sorbitol in water) from 12 to 14th post-natal days. Iron-treated rats received a standard laboratory diet or a high fat diet from weaning to adulthood (9 months of age). Recognition and emotional memory, peripheral blood glucose and insulin levels were evaluated. Glucose transporters (GLUT 1 and GLUT3) and insulin signaling were analyzed in the hippocampus of rats.

RESULTS

Both iron overload and exposure to a high fat diet induced memory deficits. Remarkably, the association of iron with the high fat diet induced more severe cognitive deficits. Iron overload in the neonatal period induced higher insulin levels associated with significantly higher HOMA-IR, an index of insulin resistance. Long-term exposure to a high fat diet resulted in higher fasting glucose levels. Iron treatment induced changes in Insr and GLUT1 expression in the hippocampus. At the level of intracellular signaling, both iron treatment and the high fat diet decreased AKT phosphorylation.

CONCLUSION

The combination of iron overload with exposure to a high fat diet only led to synergistic deleterious effect on emotional memory, while the effects induced by iron and by the high fat diet on AKT phosphorylation were comparable. These findings indicate that there is, at least to some extent, an additive effect of iron combined with the diet. Further studies investigating the mechanisms associated to deleterious effects on cognition and susceptibility for the development of age-associated neurodegenerative disorders are warranted.

High blood lead level correlates with selective hippocampal subfield atrophy and neuropsychological impairments

BACKGROUND

Lead contamination is a major public health concern. Previous studies have demonstrated that lead exposure could affect the hippocampus, which is a complex and heterogeneous structure composed of 12 subregions. Here, we explored volumetric and functional changes in hippocampal subfields and neuropsychological alterations after lead exposure.

METHODS

We performed a cross-sectional study at a smelting company between September 2020 and December 2021. Blood lead level was recorded, and neuropsychological functions were assessed by Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Self-rating Anxiety Scale (SAS), and Self-rating Depression Scale (SDS). The hippocampus was segmented into 12 subfields in each hemisphere in magnetic resonance images (MRIs). Then, the effect of altered hippocampal subfield volumes on brain functions were studied by seed-based functional connectivity (FC) analysis. Finally, the relationships between the lead level with hippocampal subfield volumes and neuropsychological functions were investigated. Baseline characteristics, hippocampal subfield volumes, and FC analysis were compared between lead-exposed (≥ 300 μg/L) and the control group (≤ 100 μg/L).

RESULTS

In 76 participants, lead level positively correlated with SDS(r = 0.422) and negatively correlated with MoCA(r = -0.414), MMSE(r = -0.251), Concentration(r = -0.331), Recall(r = -0.319), Orientation(r = -0.298) and Executive Function/Visuospatial abilities(r = -0.231). Lead group (26 participants) had lower MoCA and MMSE and higher SDS than control group (23 participants). A significantly decreased volume in the left CA4 and GC-ML-DG subfields was found in the lead group compared with the control group. The left GC-ML-DG of the lead group showed a decreased FC with the bilateral postcentral gyrus. The left CA4(r = -0.409) and left GC-ML-DG (r = -0.383) volumes negatively correlated with lead level. The FC between left GC-ML-DG and left postcentral gyrus positively correlated with MoCA(r = 0.318), MMSE(r = 0.379) and Recall(r = 0.311). The FC between left GC-ML-DG and right postcentral gyrus positively correlated with MoCA(r = 0.326), Executive Function/Visuospatial abilities(r = 0.307) and Concentration(r = 0.297).

CONCLUSION

High blood lead level was associated with neuropsychological alterations, hippocampal structural and functional changes. The left GC-ML-DG and CA4 atrophy might serve as predictive imaging markers for neurological damage associated with high lead exposure.

Perinatal Lead Exposure Promotes Sex-Specific Epigenetic Programming of Disease-Relevant Pathways in Mouse Heart

Environmental contaminants such as the metal lead (Pb) are associated with cardiovascular disease, but the underlying molecular mechanisms are poorly understood. In particular, little is known about how exposure to Pb during early development impacts the cardiac epigenome at any point across the life course and potential differences between sexes. In a mouse model of human-relevant perinatal exposures, we utilized RNA-seq and Enhanced Reduced Representation Bisulfite Sequencing (ERRBS) to investigate the effects of Pb exposure during gestation and lactation on gene expression and DNA methylation, respectively, in the hearts of male and female mice at weaning. For ERRBS, we identified differentially methylated CpGs (DMCs) or differentially methylated 1000 bp regions (DMRs) based on a minimum absolute change in methylation of 10% and an FDR < 0.05. For gene expression data, an FDR < 0.05 was considered significant. No individual genes met the FDR cutoff for gene expression; however, we found that Pb exposure leads to significant changes in the expression of gene pathways relevant to cardiovascular development and disease. We further found that Pb promotes sex-specific changes in DNA methylation at hundreds of gene loci (280 DMCs and 99 DMRs in males, 189 DMCs and 121 DMRs in females), and pathway analysis revealed that these CpGs and regions collectively function in embryonic development. In males, differential methylation also occurred at genes related to immune function and metabolism. We then investigated whether genes exhibiting differential methylation at weaning were also differentially methylated in hearts from a cohort of Pb-exposed mice at adulthood. We found that a single gene, Galnt2, showed differential methylation in both sexes and time points. In a human cohort investigating the influence of prenatal Pb exposure on the epigenome, we also observed an inverse association between first trimester Pb concentrations and adolescent blood leukocyte DNA methylation at a locus in GALNT2, suggesting that this gene may represent a biomarker of Pb exposure across species. Together, these data, across two time points in mice and in a human birth cohort study, collectively demonstrate that Pb exposure promotes sex-specific programming of the cardiac epigenome, and provide potential mechanistic insight into how Pb causes cardiovascular disease.

Avicularin Attenuates Lead-Induced Impairment of Hepatic Glucose Metabolism by Inhibiting the ER Stress-Mediated Inflammatory Pathway

Lead (Pb), an environmental hazard, causes several human diseases. Avicularin (Avi), a main dietary flavonoid found in several plants and fruits, exhibits potential protective properties on organs. However, the molecular mechanisms of Avi's protective effects against Pb-induced damage are not clear. In our study, the effects of Avi on Pb-induced hepatotoxicity were evaluated using ICR mice. We have revealed for the first time that treatment with Avi significantly reduced hepatic inflammation, endoplasmic reticulum stress (ERS) and glucose metabolism disorder induced by Pb. Avi decreased the serum biochemical indicators of glucose metabolism. Avi increased the activities of glycogenolysis rate-limiting enzyme hexokinase (HK), pyruvate kinase (PK), glucokinase (GK) and glycogen phosphorylase (PYG) and inhibited the activities of gluconeogenesis rate-limiting enzyme phosphoenolpyruvate carboxy kinase (PEPCK) and glucose-6-phosphate dehydrogenase (G6PD). Avi decreased the protein expression levels of glucose-regulated protein 78 (GRP78), phosphorylated inositol requiring enzyme 1 (p-IRE1), phosphorylated RNA-dependent protein kinase-like ER kinase (p-PERK) and phosphorylated eukaryotic initiation factor 2α (p-eIF2α). The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were decreased in the liver as a result of Avi suppression Pb-induced inflammation. These results indicated that Avi attenuated Pb-induced impairment of hepatic glucose metabolism by the ERS and inflammation pathway.

Combined exposure of lead and high-fat diet enhanced cognitive decline via interacting with CREB-BDNF signaling in male rats

The health risks to populations induced by lead (Pb) and high-fat diets (HFD) have become a global public health problem. Pb and HFD often co-exist and are co-occurring risk factors for cognitive impairment. This study investigates effect of combined Pb and HFD on cognitive function, and explores the underlying mechanisms in terms of regulatory components of synaptic plasticity and insulin signaling pathway. We showed that the co-exposure of Pb and HFD further increased blood Pb levels, caused body weight loss and dyslipidemia. The results from Morris water maze (MWM) test and Nissl staining disclosed that Pb and HFD each contributed to cognitive deficits and neuronal damage and combined exposure enhanced this toxic injury. Pb and HFD decreased the levels of synapsin-1, GAP-43 and PSD-95 protein related to synaptic properties and SIRT1, NMDARs, phosphorylated CREB and BDNF related to synaptic plasticity regulatory, and these decreases was greater when combined exposure. Additionally, we revealed that Pb and HFD promoted IRS-1 phosphorylation and subsequently reduced downstream PI3K-Akt kinases phosphorylation in hippocampus and cortex of rats, and this process was aggravated when co-exposure. Collectively, our data suggested that combined exposure of Pb and HFD enhanced cognitive deficits, pointing to additive effects in rats than the individual stress effects related to multiple signaling pathways with CREB-BDNF signaling as the hub. This study emphasizes the need to evaluate the effects of mixed exposures on brain function in realistic environment and to better inform prevention of neurological disorders via modulating central pathway, such as CREB/BDNF signaling.

A novel approach to type 3 diabetes mechanism: The interplay between noncoding RNAs and insulin signaling pathway in Alzheimer's disease

Today, growing evidence indicates that patients with type 2 diabetes (T2D) are at a higher risk of developing Alzheimer's disease (AD). Indeed, AD as one of the main causes of dementia in people aged more than 65 years can be aggravated by insulin resistance (IR) and other metabolic risk factors related to T2D which are also linked to the function of the brain. Remarkably, a new term called "type 3 diabetes" has been suggested for those people who are diagnosed with AD while also showing the symptoms of IR and T2D. In this regard, the role of genetic and epigenetic changes associated with AD has been confirmed by many studies. On the other hand, it should be noted that the insulin signaling pathway is highly regulated by various mechanisms, including epigenetic factors. Among these, the role of noncoding RNAs (ncRNAs), including microRNAs and long noncoding RNAs has been comprehensively studied with respect to the pathology of AD and the most well-known underlying mechanisms. Nevertheless, the number of studies exploring the association between ncRNAs and the downstream targets of the insulin signaling pathway in the development of AD has notably increased in recent years. With this in view, the present study aimed to review the interplay between different ncRNAs and the insulin signaling pathway targets in the pathogenesis of AD to find a new approach in the field of combining biomarkers or therapeutic targets for this disease.

Longitudinal in vivo imaging of acute neuropathology in a monkey model of Ebola virus infection

Ebola virus (EBOV) causes neurological symptoms yet its effects on the central nervous system (CNS) are not well-described. Here, we longitudinally assess the acute effects of EBOV on the brain, using quantitative MR-relaxometry, 18F-Fluorodeoxyglucose PET and immunohistochemistry in a monkey model. We report blood-brain barrier disruption, likely related to high cytokine levels and endothelial viral infection, with extravasation of fluid, Gadolinium-based contrast material and albumin into the extracellular space. Increased glucose metabolism is also present compared to the baseline, especially in the deep gray matter and brainstem. This regional hypermetabolism corresponds with mild neuroinflammation, sporadic neuronal infection and apoptosis, as well as increased GLUT3 expression, consistent with increased neuronal metabolic demands. Neuroimaging changes are associated with markers of disease progression including viral load and cytokine/chemokine levels. Our results provide insight into the pathophysiology of CNS involvement with EBOV and may help assess vaccine/treatment efficacy in real time.

Cadmium inhibits neural stem/progenitor cells proliferation via MitoROS-dependent AKT/GSK-3β/β-catenin signaling pathway

Cadmium (Cd) is a toxic heavy metal widely found in the environment. Cd is also a potential neurotoxicant, and its exposure is associated with impairment of cognitive function. However, the underlying mechanisms by which Cd induces neurotoxicity are unclear. In this study, we investigated the in vitro effect of Cd on primary murine neural stem/progenitor cells (mNS/PCs) isolated from the subventricular zone. Our results show that Cd exposure leads to mNS/PCs G1/S arrest, promotes cell apoptosis, and inhibits cell proliferation. In addition, Cd increases intracellular and mitochondrial reactive oxygen species (ROS) that activates mitochondrial oxidative stress, decreases ATP production, and increases mitochondrial proton leak and glycolysis rate in a dose-dependent manner. Furthermore, Cd exposure decreases phosphorylation of protein kinase B (AKT) and glycogen synthase kinase-3 beta (GSK3β) in mNS/PCs. In addition, pretreatment mNS/PCs with MitoTEMPO, a mitochondrial-targeted antioxidant, improves mitochondrial morphology and functions and attenuates Cd-induced inhibition of mNS/PCs proliferation. It also effectively reverses Cd-induced changes of phosphorylation of AKT and the expression of β-catenin and its downstream genes. Taken together, our data suggested that AKT/GSK3β/β-catenin signaling pathway is involved in Cd-induced mNS/PCs proliferation inhibition via MitoROS-dependent pattern.

Maternal Lead Exposure Impairs Offspring Learning and Memory via Decreased GLUT4 Membrane Translocation

Lead (Pb) can cause a significant neurotoxicity in both adults and children, leading to the impairment to brain function. Pb exposure plays a key role in the impairment of learning and memory through synaptic neurotoxicity, resulting in the cognitive function. Researches have demonstrated that Pb exposure plays an important role in the etiology and pathogenesis of neurodegenerative diseases, such as Alzheimer's disease. However, the underlying mechanisms remain unclear. In the current study, a gestational Pb exposure (GLE) rat model was established to investigate the underlying mechanisms of Pb-induced cognitive impairment. We demonstrated that low-level gestational Pb exposure impaired spatial learning and memory as well as hippocampal synaptic plasticity at postnatal day 30 (PND 30) when the blood concentration of Pb had already recovered to normal levels. Pb exposure induced a decrease in hippocampal glucose metabolism by reducing glucose transporter 4 (GLUT4) levels in the cell membrane through the phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt) pathway. In vivo and in vitro GLUT4 over-expression increased the membrane translocation of GLUT4 and glucose uptake, and reversed the Pb-induced impairment to synaptic plasticity and cognition. These findings indicate that Pb exposure impairs synaptic plasticity by reducing the level of GLUT4 in the cell membrane as well as glucose uptake via the PI3K-Akt signaling pathway, demonstrating a novel mechanism for Pb exposure-induced neurotoxicity.

Hippocampal Impairment Triggered by Long-Term Lead Exposure from Adolescence to Adulthood in Rats: Insights from Molecular to Functional Levels

Lead (Pb) is an environmental and occupational neurotoxicant after long-term exposure. This study aimed to investigate the effects of systemic Pb exposure in rats from adolescence to adulthood, evaluating molecular, morphologic and functional aspects of hippocampus. For this, male Wistar rats were exposed to 50 mg/kg of Pb acetate or distilled water for 55 days by intragastric gavage. For the evaluation of short-term and long-term memories, object recognition and step-down inhibitory avoidance tests were performed. At the end of the behavioral tests, the animals were euthanized and the hippocampus dissected and processed to the evaluation of: Pb content levels in hippocampal parenchyma; Trolox equivalent antioxidant capacity (TEAC), glutathione (GSH) and malondialdehyde (MDA) levels as parameters of oxidative stress and antioxidant status; global proteomic profile and neuronal degeneration by anti-NeuN immunohistochemistry analysis. Our results show the increase of Pb levels in the hippocampus of adult rats exposed from adolescence, increased MDA and GSH levels, modulation of proteins related to neural structure and physiology and reduced density of neurons, hence a poor cognitive performance on short and long-term memories. Then, the long-term exposure to Pb in this period of life may impair several biologic organizational levels of the hippocampal structure associated with functional damages.

Association of twenty-three plasma elements with fasting serum glucose among Chinese population from four areas with different pollution level

BACKGROUND

Association between fasting serum glucose (FSG) and certain mineral elements has been extensively reported. Investigation regarding multi-element exposure among subjects with different exposure level is warranted to confirm the association and further explore dose-dependent relationship.

METHODS

A total of 3488 participants were recruited from four counties of Hunan province, South China. Basic characteristics were collected by face to face interview and 23 elements in plasma were determined by inductively coupled plasma mass spectrometry. We applied fully adjusted generalized linear regression model and multivariable restricted cubic spline function to test the association and dose-response relationship of FSG with 23 elements.

RESULTS

The results indicated that FSG was positively associated with plasma78selenium level [regression coefficient (β), 0.001; 95 % confidence interval (CI), 0.001, 0.001] in a dose-dependent manner, robust to the adjustment for suspected covariates and stratification by age, gender, BMI and smoking status. A negative association was found between FSG and plasma 208lead (β, -0.004; 95 % CI, -0.016, -0.002), 52chromium (β, -0.002; 95 % CI, -0.004, -0.001) and 47titanium (β, -0.001; 95 % CI, -0.002, -0.001).

CONCLUSION

78selenium was positively while 208lead, 52chromium and 47titanium were negatively associated with FSG in the present study. However, prospective studies are needed to confirm the results.

Early life metal exposure dysregulates cellular bioenergetics in children with regressive autism spectrum disorder

Neurodevelopmental regression (NDR) is a subtype of autism spectrum disorder (ASD) that manifests as loss of previously acquired developmental milestones. Early life dysregulation of nutritional metals and/or exposure to toxic metals have been associated with ASD, but the underlying biological mechanisms by which metals influence neurodevelopment remain unclear. We hypothesize that metals influences neurodevelopment through dysregulation of bioenergetics. Prenatal and early postnatal metal exposures were measured using validated tooth-matrix biomarkers in 27 ASD cases (13 with NDR) and 7 typically-developing (TD) controls. Mitochondrial respiration and glycolysis were measured in peripheral blood mononuclear cells using the Seahorse XF96. Children with ASD demonstrated lower prenatal and postnatal Copper (Cu) and prenatal Nickel concentrations and Copper-to-Zinc (Cu/Zn) ratio as compared with TD children. Children with ASD and NDR showed greater metal-related disruption of cellular bioenergetics than children with ASD without NDR. For children with ASD and NDR mitochondrial respiration decreased as prenatal Manganese concentration increased and increased as prenatal Zinc concentration increased; glycolysis decreased with increased exposure to prenatal Manganese and Lead and postnatal Manganese. For children with ASD without a history of NDR, glycolysis increased with increased postnatal exposure to Tin. Language and communication scores in children with ASD were positively related to prenatal Cu exposure and Cu/Zn ratio. This study suggests that prenatal nutritional metals may be important for neurodevelopment in children with ASD, and that exposure to toxic metals and differences in nutritional metal exposures is associated with dysregulation of cellular bioenergetics, particularly in the NDR subtype of ASD.

Depression, changes in peripheral blood cell count, and changes in selected biochemical parameters related to lead concentration in whole blood (Pb-B) of women in the menopausal period

THE AIM

The aim of this study was to assess the severity of depression, vasomotor symptoms, changes in peripheral blood cell count, and selected biochemical parameters in relation to the concentration of lead in whole blood of women in the perimenopausal period.

METHODS

The study sample consisted of 233 women from the general population of the West Pomeranian Province (Poland) in age between 44-65 years. The intensity of menopausal symptoms was examined using the Blatt-Kupperman Index, and the severity of depression using the Beck Depression Inventory. The following biochemical data were evaluated: concentrations of glucose, triglycerides, HDL, C-reactive protein, glycated haemoglobin, cortisol, insulin, blood cell count, and lead concentration in whole blood (Pb-B).

RESULTS

A whole blood Pb concentration below 5 μg/dl was found in 55 subjects (23.61 %), in 142 women (60.94 %) it ranged from 5 to 10 μg/dl, while in 36 women (15.45 %) was higher than 10 μg/dl. There was a strong positive correlation between Pb concentration in the blood of the examined women and the severity of depressive symptoms (Rs=+0.60, p = 0.001). The lowest mean values for total leukocytes (5.07 ± 1.22 thousand/μl) and neutrophils (2.76 ± 0.86 thousand/μl) were found in women with Pb concentration above 10 μg/dl (p < 0.05). There was a significant negative correlation between the number of total leukocytes (r=-0.45, p = 0.002) and neutrophils (r=-0.50, p = 0.001) and blood Pb concentration. Analysis showed statistically significant differences in glucose concentration (p < 0.05) between groups. Blood glucose was higher in women with Pb-B <5 and between 5-10 μg/dl than in women with Pb-B >10 μg/dl.

CONCLUSION

Exposure to Pb may be a factor playing a significant role in the development of depressive symptoms in menopausal women. It may also be associated with glucose metabolism disorders and immunosuppression in women during this period of life.