Metals and Paraoxonases

A review of the epidemiological and laboratory evidence of the role of aluminum exposure in pathogenesis of cardiovascular diseases

The objective of the present study was to review the epidemiological and laboratory evidence on the role of aluminum (Al) exposure in the pathogenesis of cardiovascular diseases. Epidemiological data demonstrated an increased incidence of cardiovascular diseases (CVD), including hypertension and atherosclerosis in occupationally exposed subjects and hemodialysis patients. In addition, Al body burden was found to be elevated in patients with coronary heart disease, hypertension, and dyslipidemia. Laboratory studies demonstrated that Al exposure induced significant ultrastructural damage in the heart, resulting in electrocardiogram alterations in association with cardiomyocyte necrosis and apoptosis, inflammation, oxidative stress, inflammation, and mitochondrial dysfunction. In agreement with the epidemiological findings, laboratory data demonstrated dyslipidemia upon Al exposure, resulting from impaired hepatic lipid catabolism, as well as promotion of low-density lipoprotein oxidation. Al was also shown to inhibit paraoxonase 1 activity and to induce endothelial dysfunction and adhesion molecule expression, further promoting atherogenesis. The role of Al in hypertension was shown to be mediated by up-regulation of NADPH-oxidase, inhibition of nitric oxide bioavailability, and stimulation of renin-angiotensin-aldosterone system. It has been also demonstrated that Al exposure targets cerebral vasculature, which may be considered a link between Al exposure and cerebrovascular diseases. Findings from other tissues lend support that ferroptosis, pyroptosis, endoplasmic reticulum stress, and modulation of gut microbiome and metabolome are involved in the development of CVD upon Al exposure. A better understanding of the role of the cardiovascular system as a target for Al toxicity will be useful for risk assessment and the development of treatment and prevention strategies.

Nutritional epigenetics education improves diet and attitude of parents of children with autism or attention deficit/hyperactivity disorder

BACKGROUND

Unhealthy maternal diet leads to heavy metal exposures from the consumption of ultra-processed foods that may impact gene behavior across generations, creating conditions for the neurodevelopmental disorders known as autism and attention deficit/hyperactivity disorder (ADHD). Children with these disorders have difficulty metabolizing and excreting heavy metals from their bloodstream, and the severity of their symptoms correlates with the heavy metal levels measured in their blood. Psychiatrists may play a key role in helping parents reduce their ultra-processed food and dietary heavy metal intake by providing access to effective nutritional epigenetics education.

AIM

To test the efficacy of nutritional epigenetics instruction in reducing parental ultra-processed food intake.

METHODS

The study utilized a semi-randomized test and control group pretest-posttest pilot study design with participants recruited from parents having a learning-disabled child with autism or ADHD. Twenty-two parents who met the inclusion criteria were randomly selected to serve in the test (n = 11) or control (n = 11) group. The test group participated in the six-week online nutritional epigenetics tutorial, while the control group did not. The efficacy of the nutritional epigenetics instruction was determined by measuring changes in parent diet and attitude using data derived from an online diet survey administered to the participants during the pre and post intervention periods. Diet intake scores were derived for both ultra-processed and whole/organic foods. Paired sample t-tests were conducted to determine any differences in mean diet scores within each group.

RESULTS

There was a significant difference in the diet scores of the test group between the pre- and post-intervention periods. The parents in the test group significantly reduced their intake of ultra-processed foods with a pre-intervention diet score of 70 (mean = 5.385, SD = 2.534) and a post-intervention diet score of 113 (mean = 8.692, SD = 1.750) and the paired t-test analysis showing a significance of P < 0.001. The test group also significantly increased their consumption of whole and/or organic foods with a pre-intervention diet score of 100 (mean = 5.882, SD = 2.472) and post-intervention diet score of 121 (mean = 7.118, SD = 2.390) and the paired t-test analysis showing a significance of P < 0.05.

CONCLUSION

Here we show nutritional epigenetics education can be used to reduce ultra-processed food intake and improve attitude among parents having learning-disabled children with autism or ADHD.

Glutamine Is a Superior Protector Against Lead-Induced Hepatotoxicity in Rats via Antioxidant, Anti-inflammatory, and Chelating Properties

Lead acetate-motivated oxidative stress can affect all organ systems, particularly the liver. Glutamine (Gln) has both antioxidant and chelating properties. Therefore, we investigated for the first time the effect of Gln on the biochemical and histopathological alternations in a rat model of lead toxicity. Thirty-two rats were divided into four groups (eight rats in each): untreated normal, lead poisoning, and two similar groups receiving Gln (0.1% in drinking water for 4 weeks). To induce lead poisoning, rats received 50 mg/L lead acetate in drinking water for 4 weeks. Oxidative stress indices (total glutathione, the ratio of reduced glutathione to oxidized glutathione, advanced protein oxidation products, malondialdehyde, and ferric ion reducing power) and inflammatory markers (hepatic nuclear factor-kβ expression, interleukin 1β level, and myeloperoxidase activity) were measured. Furthermore, biochemical markers of hepatotoxicity (alanine transaminase, aspartate transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, total bilirubin, total protein, albumin, and globulins) were measured. Histopathological examination evaluated lead-induced liver damage. The treatment compensated lead-induced biochemical and histopathological alternations in rat liver. Furthermore, it decreased lead acetate level, the NF-kβ gene expression, oxidative stress, and inflammatory markers. Moreover, the treatment elevated total glutathione and reduced glutathione in the sera and liver homogenates of treated groups (p < 0.001). Glutamine could protect the liver against lead intoxication via antioxidant, anti-inflammatory, and chelating properties. In addition, its downregulating effect on the hepatic NF-kβ signaling pathway confirms its hepatoprotective activity.

Insights into the role of paraoxonase 2 in human pathophysiology

Paraoxonase 2 (PON2) is a ubiquitously expressed intracellular enzyme that is known to have a protective role from oxidative stress. Clinical studies have also demonstrated the significance of PON2 in the manifestation of cardiovascular and several other diseases, and hence, it is considered an important biomarker. Recent findings of its expression in brain tissue suggest its potential protective effect on oxidative stress and neuroinflammation. Polymorphisms of PON2 in humans are a risk factor in many pathological conditions, suggesting a possible mechanism of its anti-oxidative property probably through lactonase activity. However, exogenous factors may also modulate the expression and activity of PON2. Hence, this review aims to report the mechanism by which PON2 expression is regulated and its role in oxidative stress disorders such as neurodegeneration and tumor formation. The role of PON2 owing to its lactonase activity in bacterial infectious diseases and association of PON2 polymorphism with pathological conditions are also highlighted.

Serum levels of proinflammatory cytokines and selected bioelements in perimenopausal women with regard to body mass index

During the menopause, decreased estrogen levels may be accompanied by increased levels of inflammatory mediators. Many studies also show significant relationships between the levels of bioelements and proinflammatory cytokines. The aim of this study was to assess the levels of proinflammatory cytokines, C-reactive protein (CRP), and selected bioelements in perimenopausal women with regard to BMI. Methods: The study of 217 perimenopausal women involved the completion of questionnaires concerning sociodemographic and medical data, anthropometric measurements, and blood collection. Results: In all studied women, the levels of IL-1β significantly positively correlated with Ca, Mg, and Sr; IFNγ significantly negatively correlated with Sr, and IL-6 with Mg. In women with a normal BMI, the levels of IL-1β significantly positively correlated with Ca and Sr, and CRP positively correlated with Zn. In overweight women, the levels of IL-1β positively correlated with Ca, IL-6 with Na, and IFNγ negatively correlated with Sr. In obese women, the levels of CRP positively correlated with Zn, TNFα with Mg, IFNγ with Cu and P. The levels of IL-6 negatively correlated with Ca and Mg. Conclusions: BMI may be one of the factors that affect the relationship between serum bioelement levels and the levels of proinflammatory cytokines and CRP in women, especially during the menopausal period.

PPARγ/PGC1α signaling as a potential therapeutic target for mitochondrial biogenesis in neurodegenerative disorders

Neurodegenerative diseases represent some of the most devastating neurological disorders, characterized by progressive loss of the structure and function of neurons. Current therapy for neurodegenerative disorders is limited to symptomatic treatment rather than disease modifying interventions, emphasizing the desperate need for improved approaches. Abundant evidence indicates that impaired mitochondrial function plays a crucial role in pathogenesis of many neurodegenerative diseases and so biochemical factors in mitochondria are considered promising targets for pharmacological-based therapies. Peroxisome proliferator-activated receptors-γ (PPARγ) are ligand-inducible transcription factors involved in regulating various genes including peroxisome proliferator-activated receptor gamma co-activator-1 alpha (PGC1α). This review summarizes the evidence supporting the ability of PPARγ-PGC1α to coordinately up-regulate the expression of genes required for mitochondrial biogenesis in neurons and provide directions for future work to explore the potential benefit of targeting mitochondrial biogenesis in neurodegenerative disorders. We have highlighted key roles of NRF2, uncoupling protein-2 (UCP2), and paraoxonase-2 (PON2) signaling in mediating PGC1α-induced mitochondrial biogenesis. In addition, the status of PPARγ modulators being used in clinical trials for Parkinson's disease (PD), Alzheimer's disease (AD) and Huntington's disease (HD) has been compiled. The overall purpose of this review is to update and critique our understanding of the role of PPARγ-PGC1α-NRF2 in the induction of mitochondrial biogenesis together with suggestions for strategies to target PPARγ-PGC1α-NRF2 signaling in order to combat mitochondrial dysfunction in neurodegenerative disorders.

Selenium modifies associations between multiple metals and neurologic symptoms in Gulf states residents

BACKGROUND

Metals have been shown to have a wide range of neurologic effects across the life course, but most studies consider neurodevelopment or neurodegenerative diseases in older adults. We investigated exposure to metals during adulthood in association with subclinical neurologic endpoints, considering the metals individually and as a mixture, and potential interactions among exposures.

METHODS

We measured blood levels of cadmium, lead, mercury, manganese, and selenium in 1007 Gulf state residents and estimated cross-sectional associations between ranked levels of blood metals and the presence of self-reported neurologic symptoms. Single pollutant models were mutually adjusted for other metals and we used quantile g-computation to evaluate associations with exposure to the combined mixture. In stratified analyses, we assessed heterogeneity by smoking and blood selenium.

RESULTS

The highest quartile of cadmium was associated with a higher prevalence of central nervous system symptoms (prevalence ratio [PR] = 1.50; 95% confidence interval [CI] = 1.13, 1.99), with stronger associations among nonsmokers (PR = 1.63; 95% CI = 1.11, 2.38) and those with low selenium (PR = 2.29, 95% CI = 1.50, 3.49). Selenium also modified associations between lead and peripheral nervous system symptoms, with increased symptoms in the low selenium group at all quartiles of exposure (P-trend = 0.07). Conversely, those with the highest co-exposure to mercury and selenium had reduced neurologic symptoms (PR = 0.73, 95% CI = 0.55, 0.96). Results of the mixture analysis were consistent with single chemical results.

CONCLUSIONS

Cadmium exhibited the most consistent relationship with increased neurologic symptoms, though lead was an important exposure in subgroup analyses. Selenium may modify subclinical neurotoxic effects of metals at non-occupational levels in adults.

Bioaccumulation of heavy metals, lipid profiles, and antioxidant status of snails (Achatina achatina) around cement factory vicinities

Some snails (Achatina spp) can be used as a biosensor of heavy metal poisoning. This study thus estimated some heavy metal levels, antioxidant markers, and lipid profiles of snails handpicked around cement factory vicinities in Ogun State, Nigeria. Snails and soil samples were collected from Oke, Ewekoro, Papalanto, and Mowodani Imeko-Afon (control site). Lead (Pb), cadmium (Cd), and arsenic (As) levels were estimated in the soil, snail foot, hemolymph, and shell using Atomic Absorption Spectrophotometry. Triacylglycerol (TAG), phospholipids (PHOL), cholesterol (CHOL), malondialdehyde (MDA), and reduced glutathione (GSH) levels, as well as glutathione-S-transferase (GST), lactate dehydrogenase (LDH), and arylesterase (AR) activities in the hemolymph, were estimated spectrophotometrically. The snails collected from the Oke site had the highest foot Pb (274.66 ± 13.50 mg/g tissue), CHOL, TAG, PHOL levels, and GST activity when compared with other sites. Snails collected from Papa had the highest Cd levels (1.79 ± 0.74 mg/kg), As (1206 ± 18.87 mg/g tissue) in the foot, and LDH activity, while Ewekoro snails had highest MDA levels and AR activities but the lowest GSH levels. Additionally, there were negative correlations between the heavy metal levels and the activities of GST and AR as well as GSH levels, while positively correlating with LDH activity and MDA level. Workers and the general public around cement factories are at a greater risk of heavy metal-induced pathologies. More so, consumption of snails around these sites may be deleterious to health.

Comparative eye and liver differentially expressed genes reveal monochromatic vision and cancer resistance in the shortfin mako shark (Isurus oxyrinchus)

The shortfin mako, Isurus oxyrinchus is an oceanic pelagic shark found worldwide in tropical and subtropical waters. However, the understanding of its biology at molecular level is still incipient. We sequenced the messenger RNA isolated from eye and liver tissues. De novo transcriptome yielded a total of 705,940 transcripts. A total of 3774 genes were differentially expressed (DEGs), with 1612 in the eye and 2162 in the liver. Most DEGs in the eye were related to structural and signaling functions, including nonocular and ocular opsin genes, whereas nine out of ten most overexpressed genes in the liver were related to tumor suppression, wound healing, and human diseases. Furthermore, DEGs findings provide insights on the monochromatic shark vision and a repertory of cancer-related genes, which may be insightful to elucidate shark resistance to cancer. Therefore, our results provide valuable sequence resources for future functional and population studies.

Paraoxonase Activity and Phenotype Distribution in Patients with Chronic Obstructive Pulmonary Disease

OBJECTIVE

Paraoxonase 1 (PON1) and arylesterase (ARE) enzymes have an important role in the prevention of oxidative stress which is related to the pathogenesis of chronic obstructive pulmonary disease (COPD). PON1 levels vary widely among individuals and ethnic groups, which is in part associated with polymorphisms.

MATERIALS AND METHODS

We investigated PON1 and ARE activity and phenotype distribution in COPD patients and healthy individuals. Sixty six COPD patients and 59 control subjects were involved in the study. Serum PON1 and ARE activities were detected by spectrophotometric method. The ratio of salt-induced PON1 to ARE activity was used to determine phenotypes as QQ, QR, and RR.

RESULTS

COPD patients exhibited higher PON1 activity (199.1 vs 129.2, p=0.002) but lower ARE activity compared to control (21.3 vs 33.5, p=0.021). There was a significant difference between COPD and control group with respect to PON1 phenotype characteristics. RR phenotypic distribution was more common in the COPD group than in control (60.6% [95% CI: 48.8 - 72.3] versus 22.0 % [95% CI: 12.0 - 31.9], p=0.001). We also found that smoking (95.0% CI: 0.001-0.036, p<0.001) and RR phenotype (95.0% CI: 0.006 - 0.59, p=0.016) are independent determinants in COPD.

CONCLUSION

We found that RR phenotype was more common in COPD patients compared to control. Smoking and RR phenotype may be defined as independent factors associated with COPD.

Trace Elements and Paraoxonase-1 Activity in Lower Extremity Artery Disease

Oxidative stress and inflammation are candidate mechanisms to explain the potential role of exposure to metals and reduced activity of paraoxonase-1 (PON1) in age-related diseases. Both may be risk factors contributing to atherosclerosis. In the present study, inductively coupled mass spectrometry was used to explore multiple trace elements, while in-house methods were employed to measure PON1-related variables in patients with lower extremity artery disease (LEAD). Healthy controls were matched for sex, age, body weight, and relevant genotype variants. Serum concentrations of As, Ba, Cu, and Sr were higher in patients than those in controls, with a strong predictive ability to discriminate between groups. Differences in serum Pb, Cd, and Zn were negligible. Serum Cu increased when the disease was more severe, but a negative trend was noted for serum As, B, Ba, and Zn. The only variable associated with ankle-brachial index was serum Zn. Serum PON1 activity was significantly lower in LEAD patients. When the ability of serum trace elements to modulate PON1 activity was explored, the analysis revealed a unique association with serum Zn. The current results strongly suggest that Zn may have a protective effect in non-coronary atherosclerosis and indicate that this element may exert its anti-inflammatory and antioxidant functions through interactions with PON1 activity. These findings deserve confirmation and further research. In particular, the periodic evaluation of serum trace elements and the prescription of Zn supplements are easy measures to implement and that can improve the treatment of patients with LEAD.

Biomarkers of oxidative stress in blood of workers exposed to non-cholinesterase inhibiting pesticides

In occupational settings workers are often exposed to pesticides at relatively high doses compared to environmental exposures. Long-term exposure to pesticides has been associated with numerous adverse health effects in epidemiological studies, and oxidative stress is often claimed as one of the underlying mechanisms. In fact, different pesticides have been reported to induce oxidative stress due to the generation of free radicals and/or alteration in antioxidant defense enzymes. The present study examined greenhouse workers regularly exposed to diverse pesticides under integrated production system, and a group of controls of the same geographic area without any chemical exposure. Two different periods of the same crop season were assessed, one of high exposure (with greater use of pesticides) and other of low exposure (in which a less use of these compounds was made). Non-specific biomarkers of oxidative stress, e.g. thiobarbituric acid reactive substances (TBARS), ferric reducing ability of serum (FRAS), total thiol groups (SHT), gamma-glutamyl transpeptidase (GGT) and paraoxonase-1 (PON1) were measured in serum samples from all study subjects, alongside erythrocyte acetylcholinesterase (AChE). Results are suggestive of a mild increase in oxidative stress associated with pesticide exposure, which was compensated by an adaptive response to raise the antioxidant defenses and thus counter the detrimental effects of sustained oxidative stress. This response led to significantly increased levels of FRAS, SHT and PON1 in greenhouse workers relative to controls. Furthermore, AChE was decreased likely as a result of oxidative stress as workers did not use organophosphate insecticides.

Serum concentrations of trace elements and their relationships with paraoxonase-1 in morbidly obese women

The metabolic alterations associated with obesity include mineral dysregulation. Essential trace elements are nutrients with a relevant function in a large number of cellular processes and multiple roles in the correct functioning of metabolic enzymes. Paraoxonase-1 (PON1) is an antioxidant and anti-inflammatory enzyme that is compromised in obesity. In the present study, the potential alterations in trace elements in morbidly obese women were assessed in relation to serum PON1 activity and concentration, as well as to other obesity-related comorbidities such as diabetes mellitus and fatty liver. We recruited 41 morbidly obese women and 51 control individuals. The serum concentrations of 30 elements, PON1 paraoxonase and lactonase activities, and PON1 concentration were measured. We observed significant alterations in the levels of As, Ba, Cu, Ca, Fe, Mg, Na, Se, Sr, and Zn in obese women; some of them (As, Ca, Cr, Cu, Mg, and Se) being significantly correlated with serum PON1 values. The most relevant changes were observed in the concentrations of As, Sr and Mg, the last of which was also significantly associated with diabetes mellitus. The current results raise the possibility that increased ingestion and/or storage of a number of trace elements may be factors predisposing to obesity-related comorbidities and metabolic alterations.