Reduction of blood lead levels in lead-exposed mice by dietary supplements and natural antioxidants

Intestinal toxicity of Pb: Structural and functional damages, effects on distal organs and preventive strategies

Lead (Pb) is one of the most common heavy metal pollutants that possesses multi-organ toxicity. For decades, great efforts have been devoted to investigate the damage of Pb to kidney, liver, bone, blood cells and the central nervous system (CNS). For the common, dietary exposure is the main avenue of Pb, but our knowledge of Pb toxicity in gastrointestinal tract (GIT) remains quite insufficient. Importantly, emerging evidence has documented that gastrointestinal disorders affect other distal organs like brain and liver though gut-brain axis or gut-liver axis, respectively. This review focuses on the recent understanding of intestinal toxicity of Pb exposure, including structural and functional damages. We also review the influence and mechanism of intestinal toxicity on other distal organs, mainly concentrated on brain and liver. At last, we summarize the bioactive substances that reported to alleviate Pb toxicity, providing potential dietary intervention strategies to prevent or attenuate Pb toxicity.

Clerodendrum viscosum leaves attenuate lead-induced neurotoxicity through upregulation of BDNF-Akt-Nrf2 pathway in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Clerodendrum viscosum is an important medicinal plant in Ayurveda in Bangladesh and its leaves are used as a remedy for various diseases such as anti-inflammatory, antibacterial, hyperglycemic, hepatoprotective effects.

AIM OF THE STUDY

The present study aimed to evaluate the protective effect of aqueous extract of C. viscosum leaves against Pb-induced neurobehavioral and biochemical changes in mice.

MATERIALS AND METHODS

Swiss albino mice were divided as a) control, b) lead treated (Pb) and c) C. viscosum leaves (Cle) d) Pb plus Cle groups. Pb-acetate (10 mg/kg body weight) was given to Pb and Pb + Cle groups mice, and water extract of leaves (50 mg/kg body weight) was provided as supplementation to Cle and Pb + Cle groups mice for 30 days. Elevated plus maze and Morris water maze tests were used for evaluating anxiety, spatial memory and learning, respectively. Status of cholinesterase, SOD, GSH enzyme activity and neurotoxicity markers such BDNF and Nrf2 levels were analyzed in the brain tissue of experimental mice.

RESULTS

Poorer learning, inferior spatial memory, and increased anxiety-like behavior in Pb-exposure mice were noted when compared to control mice in Morris water maze and elevated plus maze test, respectively. In addition, expression of BDNF and Nrf2, cholinesterase activity along with antioxidant activity were significantly reduced compared to control group (p < 0.01). Interestingly, C. viscosum leaves' aqueous extract supplementation in Pb-exposed mice provide a significant improved neurochemical and antioxidant properties through the augmentation of activity of cholinergic enzymes, and upregulation of BDNF and Nrf2 levels in the brain tissue compared to Pb-exposed mice.

CONCLUSIONS

This study suggested that C. viscosum leaves restore the cognitive dysfunction and reduce anxiety-like behavior through upregulation of BDNF mediated Akt-Nrf2 pathway in Pb-exposure mice.

Co-supplementation of Zinc and Calcium Suppresses Bio-absorption of Lead in Sprague Dawley Rats

Lead (Pb) is a widespread environmental toxicant and its toxicity causes huge health impacts. The present study was conducted to examine the protective role of zinc (Zn) and calcium (Ca) supplements against bio-absorption of Pb in blood and organs including the liver and kidney. Hence, Sprague Dawley rats were divided in to five groups. G₁ served as negative control and was provided with standard diet, G₂ as positive control receiving standard diet + PbAc (20 mg/kg BW), G₃ was provided with standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW), G₄ with standard diet + PbAc (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW) whereas G₅ was fed on standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW). The salts were provided as solution, dissolved in 0.5 mL distilled water via orogastric tube. After 35 days, the overnight fasted rats were decapitated, and blood and organs were collected for analysis of levels of metals and liver and kidney function tests. The results depicted significant decrease in Pb concentration in blood and organs while increase in Zn and Ca absorption was observed as a result of Zn and Ca supplementation with Zn being better than Ca alone, specially however, combined effect of these supplements was more profound in improving liver and kidney stress biomarkers and maintained the normal architecture of renal and hepatic parenchyma. It was concluded that Zn and Ca co-supplementation hinder Pb absorption in blood, the liver, and kidney thus suggesting that their intake may protect from Pb toxicity.

Neuroprotective effects of vitamin C and garlic on glycoconjugates changes of cerebellar cortex in lead-exposed rat offspring

The deteriorating effects of Lead (Pb) on central nervous system (CNS) such as cerebellum has been demonstrated in previous studies. Glycoconjugates with the important role in CNS development may be affected by Pb-exposure. Utilization of antioxidant agents and herbal plants has attracted a great deal of attention on attenuating neurotoxicants-induced damage. Thus, in this study the neuroprotective effects of vitamin C and garlic on content of glycoconjugates of cerebellar cortex in Pb-exposed animals were investigated. Wistar pregnant rats were divided into: control (C), Pb-exposed (Pb) (1500 ppm lead acetate in drinking water), Pb plus vitamin C (Pb + Vit C) (500 mg/kg) intraperitoneally, Pb plus garlic (Pb + G) (1 mL /100 g body weight fresh garlic juice via gavage), Pb plus vitamin C and garlic (Pb + Vit C + G), and sham groups (Sh). Finally, levels of Pb in blood were measured in both rats and offspring on postnatal day 50 (PND50). Also, the cerebellums were removed for measuring Pb-levels and performing lectin histochemistry. Blood and cerebellar Pb-levels were increased in Pb-exposed group compared to control group (P < 0.001), whereas they were decreased significantly in Pb + Vit C, Pb + G, and Pb + Vit C + G groups (P < 0.01). By using MPA, UEA-1, and WGA lectin histochemistry, Pb-exposed group showed weak staining intensity compared to other groups. Besides, significant decrease was observed in the density of lectin-positive neurons of Pb-exposed group compared to the control group (P < 0.001). Moreover, strong staining intensity and high lectin-positive neurons were found in Pb + Vit C, Pb + G and Pb + Vit C + G groups than Pb-exposed group (P < 0.001). The present study revealed that Pb-exposure can result in alteration in the cerebellar glycoconjugates contents and co-administration of vitamin C and garlic could attenuate the adverse effects of Pb. The findings of this study revealed the ameliorating effects of vitamin C and garlic against Pb, suggesting the potential use of vitamin C and garlic as preventive agents in Pb poisoning.

(Ascorb)ing Pb Neurotoxicity in the Developing Brain

Lead (Pb) neurotoxicity is a major concern, particularly in children. Developmental exposure to Pb can alter neurodevelopmental trajectory and has permanent neuropathological consequences, including an increased vulnerability to further stressors. Ascorbic acid is among most researched antioxidant nutrients and has a special role in maintaining redox homeostasis in physiological and physio-pathological brain states. Furthermore, because of its capacity to chelate metal ions, ascorbic acid may particularly serve as a potent therapeutic agent in Pb poisoning. The present review first discusses the major consequences of Pb exposure in children and then proceeds to present evidence from human and animal studies for ascorbic acid as an efficient ameliorative supplemental nutrient in Pb poisoning, with a particular focus on developmental Pb neurotoxicity. In doing so, it is hoped that there is a revitalization for further research on understanding the brain functions of this essential, safe, and readily available vitamin in physiological states, as well to justify and establish it as an effective neuroprotective and modulatory factor in the pathologies of the nervous system, including developmental neuropathologies.

Zhiqi Granules Decreased Lead Level but Increased Iron Level in Serum of Chinese Children with Moderately Elevated Blood Lead Levels

To observe and compare the effects of healthy instruction and Zhiqi granules on lead, calcium, iron, and zinc levels in serum of children with moderately elevated blood lead levels (BLLs). At the same time, the possible mechanisms were discussed. A total of 60 eligible boys aged 4-6 years were selected and divided into two groups (the healthy instruction group and the Zhiqi group) randomly. The boys in the healthy instruction group only received the healthy instruction. Besides the healthy instruction, the boys in the Zhiqi group received 2 g Zhiqi granules orally one time daily. The study lasted for 4 weeks. BLL and serum iron, zinc, and calcium levels of the subjects in the two groups before and after interventions were measured and compared. After the interventions, the BLL in the Zhiqi group lowered significantly, but the decrease of the BLL in the healthy instruction group is not significant, and there was a significant difference in the BLL between the two groups. When the trial was completed, the serum iron level in the Zhiqi group increased significantly, but that in the healthy instruction group changed slightly, and a significant difference was seen between the two groups. There were no significant differences in both serum Ca and Zn levels in these two groups before and after the interventions. Meanwhile, there were no significant differences in serum Ca and Zn levels between the two groups after the interventions. The results suggested that daily intake of Zhiqi granules for 4 weeks together with healthy instruction resulted in a decrease of the BLL and an elevation of the serum iron level.

Potential Antioxidant Activity of Calcium and Selected Oxidative Stress Markers in Lead- and Cadmium-Exposed Workers

Occupational lead (Pb) and cadmium (Cd) exposure occurs during processing and casting of nonferrous metals such as zinc. In contrast to Pb and Cd, Ca is essential for living organisms due to its important role in a multitude of functions, from cell signaling to bone growth. Pb and Cd exposure affects calcium metabolism in various ways. The aim of this study was to investigate the blood levels of Pb, Cd, and Ca and the levels of selected oxidative stress biomarkers in workers exposed to Pb and Cd. Population groups included 264 male employees in a lead-zinc smelter. The study population was divided into two subgroups based on the median of Ca serum level (2.42 mmol/l): the low-Ca-level group (L-Ca group) and the high-Ca-level group (H-Ca group). Ca level was significantly higher in the H-Ca group than in the L-Ca group due to the study design (by 26%). The level of zinc protoporphyrin (ZPP) was significantly higher in the L-Ca group than in the H-Ca group by 13%, while the blood lead levels (PbB) were similar in the examined groups. The level of cadmium (CdB) was significantly higher in the L-Ca group than in the H-Ca group by 33%. From oxidative stress markers in serum, only the levels of malondialdehyde (MDA) and ceruloplasmin (CER) were significantly higher in the L-Ca group than in the H-Ca group, by 12% and 4%, respectively. The correlation analysis showed negative correlations between Ca level and the levels of PbB, ZPP, CdB, and MDA. The presented results indicate that Ca level modulates the serum concentration of Cd and has an impact on Pb-induced impairment of heme synthesis. The higher Ca levels may lead to a decrease in the concentration of lipid peroxidation products. Moreover, serum calcium level seems to be able to modify the level of acute-phase proteins. Obtained results suggest that higher Ca level may be useful in reducing Cd level in occupationally exposed workers.

Protective Effects of Dietary Supplements Containing Probiotics, Micronutrients, and Plant Extracts Against Lead Toxicity in Mice

Lead (Pb) intoxication is a serious food safety issue, and the development of relevant dietary strategies is an area of ongoing research. In this study, two different dietary supplements were designed and evaluated for their effects against Pb toxicity in mice. Dietary supplement A contained grape seed extract, tea polyphenols and Lactobacillus plantarum CCFM8661, and dietary supplement B contained vitamin C, calcium carbonate, zinc acetate, and L. plantarum CCFM8661. The results showed that both dietary supplements could effectively decrease Pb levels, protect aminolevulinic acid dehydratase, superoxide dismutase and catalase activities and recover glutathione, zinc protoporphyrin and malondialdehyde levels in tissues and blood of mice. A step-through passive avoidance task confirmed that the dietary supplements could recover the learning and memory capacities of Pb-exposed mice. The protective effects of both dietary supplements to alleviate oxidative stress and cognitive impairments were superior to the chelator treatment. Administration of the dietary supplements during Pb exposure offered more significant protection than administration after Pb exposure. Animal safety evaluation also indicated that these dietary supplements barely induced side effects in the mice. This study provides evidence that dietary supplements containing probiotics, micronutrients, and plant extracts can be considered a new dietary strategy against Pb toxicity.

WIC Participation and Blood Lead Levels among Children 1-5 Years: 2007-2014

BACKGROUND

The CDC recommends a targeted strategy for childhood blood lead screening based on participation in federal programs, such as Medicaid and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Yet, there is scarcity of data on blood lead levels (BLLs) among WIC participants.

OBJECTIVE

Our objective was to investigate whether children participating in WIC and not enrolled in Medicaid, who have not been targeted in the historical Medicaid-focused screening strategy, have higher BLLs than children in neither of these programs.

METHODS

The analysis included 3,180 children 1-5 y of age in the National Health and Nutrition Examination Surveys conducted in 2007-2014. Log-binomial regression, which allows direct estimation of prevalence ratios, was used to examine associations between WIC participation (in conjunction with Medicaid enrollment) and having BLLs ≥5 μg/dL with adjustment for age (1-2 vs. 3-5 y).

RESULTS

The percentage of children participating in "WIC only," "Medicaid only," "both WIC and Medicaid," and "neither" were 18.9%, 10.8%, 25.4%, and 44.9%, respectively. "WIC only," "Medicaid only," and "both WIC and Medicaid" children were more likely to have BLLs ≥5 μg/dL than children who were not enrolled in either program, with adjusted prevalence ratios of 3.29 [95% confidence interval (CI): 1.19, 9.09], 4.56 (95% CI: 2.18, 9.55), and 2.58 (95% CI: 1.18, 5.63).

CONCLUSIONS

Children participating in WIC but not Medicaid were more likely to have BLLs ≥5 μg/dL than children who were not enrolled in either program. These findings may inform public health recommendations and clinical practice guidelines. https://doi.org/10.1289/EHP2384

Heavy metal exposure and nasal Staphylococcus aureus colonization: analysis of the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Heavy metals including lead and cadmium can disrupt the immune system and the human microbiota. and are increasingly of concern with respect to the propogation of antibiotic-resistence. Infection by methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of global morbidity and mortality. Heavy metal exposure may be associated with increased MRSA colonization and infection, and a decrease in methicillin-susceptible Staphylococcus aureus (MSSA) through co-selection mechanisms and natural selection of antibiotic resistance in the presence of heavy metals. This study examines the association between blood lead (Pb) and cadmium (Cd) level, and MRSA and MSSA nasal colonization.

METHODS

All data used for this analysis came from the 2001-2004 National Health and Nutrition Examination Survey (NHANES). The analytical sample consisted of 18,626 participants aged 1 year and older. Multivariate logistic regression, including adjustment for demographic and dietary factors, was used to analyze the association between blood Pb and Cd, and nasal colonization by MRSA and MSSA.

RESULTS

Prevalence of MRSA and MSSA carriage were 1.2%, and 29.3% respectively. MRSA was highest in women, individuals age 70 and older, who self-identified as black, had only a high school diploma, lived below 200% of the Federal Poverty Level, and had a history of smoking. While not significantly different from those colonized with MSSA, geometric mean blood Pb (1.74 μg/dL) and blood Cd (0.31 μg/L) were highest in those colonized with MRSA. Associations with MRSA colonization appeared to increase in a dose-dependent manner with increasing quartile of blood Pb level. Blood Cd level in the fourth quartile was also significantly associated with lower odds of MRSA colonization. Both metals were associated with lower odds of MSSA colonization.

CONCLUSIONS

Both MRSA and MSSA results suggest that general population levels of blood Pb but not Cd are associated with differences in nasal carriage of S. aureus. While further research is needed, reduction in heavy metal exposures such as lead, concurrently with maintaining a healthy microbiota may be two modifiable options to consider in the fight against antibiotic-resistance.

Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines

The last few decades have seen the rise of alternative medical approaches including the use of herbal supplements, natural products, and traditional medicines, which are collectively known as 'Complementary medicines'. However, there are increasing concerns on the safety and health benefits of these medicines. One of the main hazards with the use of complementary medicines is the presence of heavy metal(loid)s such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). This review deals with the characteristics of complementary medicines in terms of heavy metal(loid)s sources, distribution, bioavailability, toxicity, and human risk assessment. The heavy metal(loid)s in these medicines are derived from uptake by medicinal plants, cross-contamination during processing, and therapeutic input of metal(loid)s. This paper discusses the distribution of heavy metal(loid)s in these medicines, in terms of their nature, concentration, and speciation. The importance of determining bioavailability towards human health risk assessment was emphasized by the need to estimate daily intake of heavy metal(loid)s in complementary medicines. The review ends with selected case studies of heavy metal(loid) toxicity from complementary medicines with specific reference to As, Cd, Pb, and Hg. The future research opportunities mentioned in the conclusion of review will help researchers to explore new avenues, methodologies, and approaches to the issue of heavy metal(loid)s in complementary medicines, thereby generating new regulations and proposing fresh approach towards safe use of these medicines.

Milk and Dairy Products Intake Is Associated with Low Levels of Lead (Pb) in Workers highly Exposed to the Metal

Lead (Pb) is a toxic metal, frequently associated with occupational exposure, due to its widespread use in industry and several studies have shown high Pb levels in workers occupationally exposed to the metal. The aim of this study was to evaluate the influence of milk and dairy products (MDP) on Pb levels in blood (B-Pb), plasma (P-Pb), and urine (U-Pb), in workers from automotive battery industries in Brazil. The study included 237 male workers; information concerning diet and lifestyle were gathered through a questionnaire, and B-Pb, P-Pb, and U-Pb were determined by ICP-MS. Mean B-Pb, P-Pb, and U-Pb were 21 ± 12, 0.62 ± 0.73 μg/dL, and 39 ± 47 μg/g creatinine, respectively. Forty three percent of participants declared consuming ≤3 portions/week of MDP (classified as low-MDP intake), while 57% of individuals had >3portions/week of MDP (high-MDP intake). B-Pb and P-Pb were correlated with working time (r _s  = 0.21; r _s  = 0.20; p < 0.010). Multivariable linear regressions showed a significant influence of MDP intake on B-Pb (β = -0.10; p = 0.012) and P-Pb (β = -0.16; p < 0.010), while no significance was seen on U-Pb. Our results suggest that MDP consumption may modulate Pb levels in individuals highly exposed to the metal; these findings may be due to the Pb-Ca interactions, since the adverse effects of Pb are partially based on its interference with Ca metabolism and proper Ca supplementation may help to reduce the adverse health effects induced by Pb exposure.

Protective effects of ascorbic acid and garlic extract against lead-induced apoptosis in developing rat hippocampus

Lead exposure has negative effects on developing nervous system and induces apoptosis in newly generated neurons. Natural antioxidants (i.e. Ascorbic acid and Garlic) might protect against lead-induced neuronal cell damage. The aim of the present study was to investigate the protective effects of Ascorbic acid and Garlic administration during pregnancy and lactation on lead-induced apoptosis in rat developing hippocampus. Timed pregnant Wistar rats were administrated with Lead (1500 ppm) via drinking water (Pb group) or lead plus Ascorbic acid (Pb + AA Group, 500 mg/kg, IP), or lead plus Garlic Extract (Pb + G Group, 1 ml garlic juice/100 g BW, via Gavage) from early gestation (GD 0) until postnatal day 50 (PN 50). At the end of experiments, the pups' brains were carefully dissected. To identify neuronal death, the brain sections were stained with TUNEL assay. Mean of blood and brain lead levels increased significantly in Pb group comparing to other studied groups (P < 0.01). There was significant reduction in blood and brain lead level in Pb + AA and Pb + G groups when compared to those of Pb group (P < 0.01). The mean number of TUNEL positive cells in the CA1, CA3, and DG was significantly lower in the groups treated by either Ascorbic acid or Garlic (P < 0.05). Administration of Ascorbic acid and Garlic during pregnancy and lactation protect against lead-induced neuronal cell apoptosis in the hippocampus of rat pups partially via the reduction of Pb concentration in the blood and in the brain.

Genomics and Evolution in Traditional Medicinal Plants: Road to a Healthier Life

Medicinal plants have long been utilized in traditional medicine and ethnomedicine worldwide. This review presents a glimpse of the current status of and future trends in medicinal plant genomics, evolution, and phylogeny. These dynamic fields are at the intersection of phytochemistry and plant biology and are concerned with the evolution mechanisms and systematics of medicinal plant genomes, origin and evolution of the plant genotype and metabolic phenotype, interaction between medicinal plant genomes and their environment, the correlation between genomic diversity and metabolite diversity, and so on. Use of the emerging high-end genomic technologies can be expanded from crop plants to traditional medicinal plants, in order to expedite medicinal plant breeding and transform them into living factories of medicinal compounds. The utility of molecular phylogeny and phylogenomics in predicting chemodiversity and bioprospecting is also highlighted within the context of natural-product-based drug discovery and development. Representative case studies of medicinal plant genome, phylogeny, and evolution are summarized to exemplify the expansion of knowledge pedigree and the paradigm shift to the omics-based approaches, which update our awareness about plant genome evolution and enable the molecular breeding of medicinal plants and the sustainable utilization of plant pharmaceutical resources.

Pb2+ induces gastrin gene expression by extracellular signal-regulated kinases 1/2 and transcription factor activator protein 1 in human gastric carcinoma cells

Divalent lead ions (Pb(2+) ) are toxic environmental pollutants known to cause serious health problems in humans and animals. Absorption of Pb(2+) from air, water, and food takes place in the respiratory and digestive tracts. The ways in which absorbed Pb(2+) affects cell physiology are just beginning to be understood at the molecular level. Here, we used reverse transcription PCR and Western blotting to analyze cultures of human gastric carcinoma cells exposed to 10 μM lead nitrate. We found that Pb(2+) induces gastrin hormone gene transcription and translation in a time-dependent manner. Promoter deletion analysis revealed that activator protein 1 (AP1) was necessary for gastrin gene transcription in cells exposed to Pb(2+) . MitogIen-activated protein kinase (MAPK)/ERK kinase inhibitor PD98059 suppressed the Pb(2+) -induced increase in messenger RNA. Epidermal growth factor receptor (EGFR) inhibitors AG1478 and PD153035 reduced both transcription and phosphorylation by extracellular signal-regulated kinase (ERK1/2). Cells exposed to Pb(2+) also increased production of c-Jun protein, a component of AP1, and over-expression of c-Jun enhanced activation of the gastrin promoter. In sum, the findings suggest the EGFR-ERK1/2-AP1 pathway mediates the effects of Pb(2+) on gastrin gene activity in cell culture.

Risk factors for lead exposure in adult population in southern Brazil

In Brazil there is no systematic evaluation to access blood lead levels (BLL) in the general population and few studies with adults have been published. The aim of this study was to examine the socioeconomic, environmental, and lifestyle determinants of BLL in the adult Brazilian population. In total, 959 adults, aged 40 years or more, were randomly selected in a city in southern Brazil. Information on socioeconomic, dietary, lifestyle, and occupational background was obtained by interviews. A spatial analysis was conducted to discern whether there were any identifiable sources of exposure. BLL were measured by inductively coupled plasma-mass spectrometry. There was an adjustment for gender, age, race, education, income class, smoking status, alcohol consumption, occupation, and red meat or cow milk consumption (Model 1), and for occupation and gender (Model 2). The geometric mean of BLL was 1.97 μg/dl (95% CI: 1.9-2.04 μg/dl). In Model 1, BLL were positively associated with male gender, older age, and drinking and smoking habits, and less frequently with milk consumption. In Model 2, data showed higher BLL in non-white than white participants, in former smokers and individuals with current or former employment in lead (Pb) industries. The participants living in the area with more Pb industries had higher BLL (3.3 μg/dl) compared with those residing in other areas with no or fewer Pb industries (1.95 μg/dl). Despite the low BLL found in adults living in an urban area, Pb industries need to be monitored and regulatory laws implemented to prevent metal contamination in urban settings.