Aluminum Trichloride Induces Hypertension and Disturbs the Function of Erythrocyte Membrane in Male Rats

Environmental exposure to metal(loid)s and hypertensive disorders of pregnancy: A systematic review

BACKGROUND

Environmental exposure to metal(loid)s has been associated with adverse effects on human health, but the systemic repercussion of these elements on the development of hypertensive disorders of pregnancy (HDP) is still poorly understood.

OBJECTIVE

To summarize evidence published about the influence of environmental exposure to aluminum, arsenic, barium, cadmium, lead, strontium and mercury on the development of HDP.

METHODS

We conducted a systematic literature review according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The search strategy was validated by the Peer Review of Electronic Search Strategies. We searched for articles published up to February 2023 in seven databases without language restriction. Two researchers conducted the steps for selection, data extraction and evaluation of the methodological quality of the instruments for epidemiological studies of the Joanna Briggs Institute. Any disagreements were resolved by a third researcher.

RESULTS

We obtained 5076 records, of which 37 articles met the inclusion criteria moderate to high methodological quality. Single exposure to metal(loid)s was predominant, and the leading biological matrix analyzed to detect the concentrations from exposure was maternal blood. Lead was the metal investigated the most, and had the largest number of studies showing positive association with HDP. In relation to the other metal(loid)s, higher levels were found in women with HDP in comparison with healthy women, but the finding of a cause-effect relationship was inconsistent.

CONCLUSIONS

Although we found evidence of harmful effects of the metal(loid)s studied on human health, the results were inconclusive with regard to HDP. Longitudinal studies that consider prospective investigation, adjustment of confounding factors and the interference of other contaminants in the exacerbation of oxidative stress in women from the preconception phase to the puerperal period should be encouraged.

A Bayesian network for estimating hypertension risk due to occupational aluminum exposure

Background

The correlation between metals and hypertension, such as sodium, zinc, potassium, and magnesium, has been confirmed, while the relationship between aluminum and hypertension is not very clear. This study aimed to evaluate the correlation between plasma aluminum and hypertension in electrolytic aluminum workers by the Bayesian networks (BN).

Methods

In 2019, 476 male workers in an aluminum factory were investigated. The plasma aluminum concentration of workers was measured by inductively coupled plasma mass spectrometry. The influencing factors on the prevalence of hypertension were analyzed by the BN.

Results

The prevalence of hypertension was 23.9% in 476 male workers. The risk of hypertension from plasma aluminum in the Q2, Q3, and Q4 groups was 5.20 (1.90-14.25), 6.92 (2.51-19.08), and 7.33 (2.69-20.01), respectively, compared with that in the Q1 group. The risk of hypertension from the duration of exposure to aluminum of >10 years was 2.23 (1.09-4.57), compared without aluminum exposure. Area under the curve was 0.80 of plasma aluminum and the duration of exposure to aluminum was based on covariates, indicating that aluminum exposure had important predictive value in the prevalence of hypertension in the occupational population. The results of the study using the BN model showed that if the plasma aluminum of all participants was higher than Q4 (≥47.86 µg/L) and the participants were drinking, smoking, diabetes, central obesity, dyslipidemia, and aged >50 years, the proportion of hypertension was 71.2%.

Conclusions

The prevalence of hypertension increased significantly with the increase of plasma aluminum level.

Ameliorative anti-coagulant, anti-oxidative and anti-ferroptotic activities of nanocurcumin and donepezil on coagulation, oxidation and ferroptosis in Alzheimer's disease

Alzheimer's disease (ad) is a neurological condition that worsens over time and is characterized by the buildup of amyloid (Aβ) plaques in the brain parenchyma. Neuroprotection and cholinesterase inhibition have been the two primary techniques used in the creation of medications to date. In ad, a novel sort of programmed cell death known as ferroptosis takes place along with iron buildup, lipid peroxidation, and glutathione deficiency. The objective of the current investigation was to examine the neuroprotective and anti-ferroptotic role of nanocurcumin and Donepezil against model of aluminum chloride AlCl3 and D-galactose induced ad. The experiment was performed on 70 rats divided into (G1: control, G2: NCMN, G3: Donepezil, G4: ad-model, G5: Donepezil co-treatment, G6: NCMN co-treatment and G7: NCMN+Donepezil co-treatment). Hematological parameters and biochemical investigations as oxidative stress, liver function, kidney function, iron profile and plasma fibrinogen were evaluated. Treatment with Nanocurcumin alone or in combination with Donepezil improved oxidative stress, liver functions, and kidney functions, improve iron profile and decreased plasma fibrinogen.

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.

Association between aluminum and iron exposure in maternal blood and umbilical cord blood and congenital heart defects in children

Background

Congenital heart disease (CHDs) is the major cause of mortality from birth defects, affecting up to 1% of live births worldwide. However, the relationship between aluminum (Al) and iron (Fe) levels and the risk of CHDs has yielded inconsistent results.

Methods

We conducted a pair-matched case-control study that included 97 CHDs and 194 non-CHDs to investigate the association and interaction between Al/Fe exposure and the risk of CHDs in a birth cohort study in Lanzhou, China.

Results

Higher concentrations of cord blood Al were associated with a greater risk of total CHDs (aOR = 2.826, 95% CI [1.009-7.266]) and isolated CHDs (aOR = 10.713, 95% CI [1.017-112.851]) compared to the lowest Al level. Both in maternal blood and cord blood, a significant dose-effect was observed between Al level and total CHDs (Ptrend < 0.05), but a similar pattern was not observed for Fe. High Al in addition to high Fe appeared to elicit a stronger association with CHDs than both lowest tertile of Al and Fe level in umbilical cord blood, particularly for multiple CHDs, septal defects and patent ductus arteriosus.

Conclusions

Our study suggests that exposure to Al during pregnancy (≥2,408 μg/L) is significantly associated with an increased risk of CHDs in offspring, especially septal defects, and that high levels of Al and Fe are strongly correlated with fetal heart development. Further research is needed to understand the underlying mechanisms.

Recent insights into autophagy and metals/nanoparticles exposure

Some anthropogenic pollutants, such as heavy metals and nanoparticles (NPs), are widely distributed and a major threat to environmental safety and public health. In particular, lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg) have systemic toxicity even at extremely low concentrations, so they are listed as priority metals in relation to their significant public health burden. Aluminum (Al) is also toxic to multiple organs and is linked to Alzheimer's disease. As the utilization of many metal nanoparticles (MNPs) gradually gain traction in industrial and medical applications, they are increasingly being investigated to address potential toxicity by impairing certain biological barriers. The dominant toxic mechanism of these metals and MNPs is the induction of oxidative stress, which subsequently triggers lipid peroxidation, protein modification, and DNA damage. Notably, a growing body of research has revealed the linkage between dysregulated autophagy and some diseases, including neurodegenerative diseases and cancers. Among them, some metals or metal mixtures can act as environmental stimuli and disturb basal autophagic activity, which has an underlying adverse health effect. Some studies also revealed that specific autophagy inhibitors or activators could modify the abnormal autophagic flux attributed to continuous exposure to metals. In this review, we have gathered recent data about the contribution of the autophagy/mitophagy mediated toxic effects and focused on the involvement of some key regulatory factors of autophagic signaling during exposure to selected metals, metal mixtures, as well as MNPs in the real world. Besides this, we summarized the potential significance of interactions between autophagy and excessive reactive oxygen species (ROS)-mediated oxidative damage in the regulation of cell survival response to metals/NPs. A critical view is given on the application of autophagy activators/inhibitors to modulate the systematic toxicity of various metals/MNPs.

Comparative Transcriptome Profiling Reveals Key MicroRNAs and Regulatory Mechanisms for Aluminum Tolerance in Olive

Aluminum toxicity (Al) is one of the major constraints to crop production in acidic soils. MicroRNAs (miRNAs) have emerged as key regulatory molecules at post-transcriptional levels, playing crucial roles in modulating various stress responses in plants. However, miRNAs and their target genes conferring Al tolerance are poorly studied in olive (Olea europaea L.). Here, genome-wide expression changes in miRNAs of the roots from two contrasting olive genotypes Zhonglan (ZL, Al-tolerant) and Frantoio selezione (FS, Al-sensitive) were investigated by high-throughput sequencing approaches. A total of 352 miRNAs were discovered in our dataset, consisting of 196 conserved miRNAs and 156 novel miRNAs. Comparative analyses showed 11 miRNAs have significantly different expression patterns in response to Al stress between ZL and FS. In silico prediction identified 10 putative target gene of these miRNAs, including MYB transcription factors, homeobox-leucine zipper (HD-Zip) proteins, auxin response factors (ARF), ATP-binding cassette (ABC) transporters and potassium efflux antiporter. Further functional classification and enrichment analysis revealed these Al-tolerance associated miRNA-mRNA pairs are mainly involved in transcriptional regulation, hormone signaling, transportation and metabolism. These findings provide new information and perspectives into the regulatory roles of miRNAs and their target for enhancing Al tolerance in olives.

Associations between plasma metal mixture exposure and risk of hypertension: A cross-sectional study among adults in Shenzhen, China

Background

Metal exposure affects human health. Current studies mainly focus on the individual health effect of metal exposure on hypertension (HTN), and the results remain controversial. Moreover, the studies assessing overall effect of metal mixtures on hypertension risk are limited.

Methods

A cross-sectional study was conducted by recruiting 1,546 Chinese adults who attended routine medical check-ups at the Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen. The plasma levels of 13 metals were measured using inductively coupled plasma mass spectrometry. Multivariate logistic regression model, restricted cubic spline (RCS) model and the Bayesian Kernel Machine Regression (BKMR) model were applied to explore the single and combined effect of metals on the risk of HTN.

Results

A total of 642 (41.5%) participants were diagnosed with HTN. In the logistic regression model, the adjusted odds ratios (ORs) were 0.71 (0.52, 0.97) for cobalt, 1.40 (1.04, 1.89) for calcium, 0.66 (0.48, 0.90), and 0.60 (0.43, 0.83) for aluminum in the second and third quartile, respectively. The RCS analysis showed a V-shaped or an inverse V-shaped dose-response relationship between metals (aluminum or calcium, respectively) and the risk of HTN (P for non-linearity was 0.017 or 0.009, respectively). However, no combined effect was found between metal mixture and the risk of hypertension.

Conclusions

Plasma levels of cobalt, aluminum and calcium were found to be associated with the risk of HTN. Further studies are needed to confirm our findings and their potential mechanisms with prospective studies and experimental study designs.

Blood pressure mediated the effects of cognitive function impairment related to aluminum exposure in Chinese aluminum smelting workers

OBJECTIVES

The aim of this study is to investigate the effects that the Al on blood pressure and the effect of hypertension in aluminum-induced cognitive impairment in electrolytic aluminum worker.

METHODS

The study was conducted 392 male aluminum electrolytic workers in an aluminum plant of China. The concentration of alumina dust in the air of the electrolytic aluminum workshop is 1.07mg/m3-2.13mg/m3. According to the Permissible concentration-Time Weighted Average of alumina dust is 4mg/ m3, which does not exceed the standard. The blood pressure of the workers was measured. The plasma aluminum concentration of workers was determined by ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Cognitive functions were measured using MMSE (Mini-Mental State Examination), VFT (Verbal Fluency Test), ATIME (Average Reaction Time), FOM (Fuld Object Memory Evaluation), DST (Digit Span Test), CDT (Clock Drawing Test) scales. Modified Poisson regression was used to analyze the risk of hypertension and cognitive impairment with different plasma aluminum concentrations. Generalized linear regression model was used to analyze the relationship between aluminum and cognitive function, blood pressure and cognitive function. Causal Mediation Analysis was used to analyze the mediation effect of blood press in aluminum-induced cognitive impairment.

RESULTS

Plasma aluminum appeared to be a risk factor for hypertension (PR (prevalence ratio) = 1.630, 95%-CI (confidence interval): 1.103 to 2.407), systolic blood pressure (PR = 1.578, 95%-CI: 1.038 to 2.399) and diastolic blood pressure (PR = 1.842, 95%-CI: 1.153 to 2.944). And plasma aluminum increased by e-fold, the scores of MMSE and VFT decreased by 0.630 and 2.231 units respectively and the time of ATIME increased by 0.029 units. In addition, generalized linear regression model showed that blood press was negatively correlated with the scores of MMSE and VFT. Finally, causal Mediation Analysis showed that hypertension was a part of the mediating factors of aluminum-induced decline in MMSE score, and the mediating effects was 16.300% (7.100%, 33.200%). In addition, hypertension was a part of the mediating factors of aluminum-induced decline in VFT score, and the mediating effects was 9.400% (2.600%, 29.000%) CONCLUSION: Occupational aluminum exposure increases the risk of hypertension and cognitive impairment. And hypertension may be a mediating factor of cognitive impairment caused by aluminum exposure.

Factors Affecting the Aluminum, Arsenic, Cadmium and Lead Concentrations in the Knee Joint Structures

Background: Toxic elements, such as aluminum (Al), arsenic (As), cadmium (Cd), and lead (Pb), are persistent environmental pollutants that can cause adverse effects on the health of exposed individuals. Bone is one of the primary target organs of accumulation and potential damage from toxic elements. Objectives: This study was performed to determine the Al, As, Cd, and Pb concentrations in the femoral cancellous bone, femoral cartilage, anterior cruciate ligament, meniscus, tibial cartilage, tibial cancellous bone and infrapatellar fat pad. Furthermore, the aim of this study was to explore the relationships between toxic element concentrations and related factors such as gender, age, place of residence, hypertension and diabetes, and to determine the correlations among these toxic elements in knee joint structures. Methods: The samples used this study were collected from 51 patients following total knee arthroplasty. The Al, As, Cd, and Pb concentrations were determined using inductively coupled plasma optic emission spectrometry. Results: Significant differences were found in the Al, As, Cd, and Pb concentrations among the knee joint structures. Cd concentration in the tibial cancellous bone in women was significantly higher than in men. Pb concentration in the infrapatellar fat pad of urban patients was significantly higher as compared to rural patients. Al concentrations in the femoral cancellous bone, femoral cartilage, anterior cruciate ligament, meniscus and tibial cartilage were significantly higher in patients living in urban areas than in rural areas. As concentration in the tibial cancellous bone of diabetic patients was significantly higher compared to non-diabetic patients. In addition, significant Spearman's positive correlations were found between Al and Pb in the knee joint structures. Conclusion: The obtained results of the investigated toxic elements may serve as a basis for establishing the reference values of Al, As, Cd, and Pb in the knee joint structures. The results reported in the study provides novel data regarding the relationships between the toxic element concentrations and gender, age, place of residence, hypertension and diabetes in the studied structures of knee joint. Furthermore, new interactions among these toxic elements were noted.

Bioactive Peptides and Hydrolysates from Egg Proteins as a New Tool for Protection Against Cardiovascular Problems

The aim of the present work is to review the potential beneficial effects of dietary supplementation with bioactive egg protein hydrolysates or peptides on cardiometabolic changes associated with oxidative stress. The development of nutritionally improved food products designed to address specific health concerns is of particular interest because many bioactive food compounds can be potentially useful in various physiological functions such as for reducing oxidative stress. The results presented suggest that egg hydrolysates or derived peptides could be included in the diet to prevent and/or reduce some cardiometabolic complications associated with oxidative stress-related diseases.

Aluminium adjuvants in vaccines - A way to modulate the immune response

Aluminium salts have been used as adjuvants in vaccines for almost a century, but still no clear understanding of the mechanisms behind the immune stimulating properties of aluminium based adjuvants is recognized. Aluminium adjuvants consist of aggregates and upon administration of a vaccine, the aggregates will be recognized and phagocytosed by sentinel cells such as macrophages or dendritic cells. The adjuvant aggregates will persist intracellularly, maintaining a saturated intracellular concentration of aluminium ions over an extended time. Macrophages and dendritic cells are pivotal cells of the innate immune system, linking the innate and adaptive immune systems, and become inflammatory and antigen-presenting upon activation, thus mediating the initiation of the adaptive immune system. Both types of cell are highly adaptable, and this review will discuss and highlight how the occurrence of intracellular aluminium ions over an extended time may induce the polarization of macrophages into inflammatory and antigen presenting M1 macrophages by affecting the: endosomal pH; formation of reactive oxygen species (ROS); stability of the phagosomal membrane; release of damage associated molecular patterns (DAMPs); and metabolism (metabolic re-programming). This review emphasizes that a persistent intracellular presence of aluminium ions over an extended time has the potential to affect the functionality of sentinel cells of the innate immune system, inducing polarization and activation. The immune stimulating properties of aluminium adjuvants is presumably mediated by several discrete events, however, a persistent intracellular presence of aluminium ions appears to be a key factor regarding the immune stimulating properties of aluminium based adjuvants.

Aluminium levels in hair and urine are associated with overweight and obesity in a non-occupationally exposed population

BACKGROUND

Data on the association between aluminium (Al) exposure and obesity and/or metabolic syndrome are insufficient. The objective of the present study was to investigate the association between hair and urine Al levels and obesity.

METHODS

A total of 206 lean and 205 obese non-occupationally exposed subjects (30-50 y.o.) were enrolled in the study. Hair and urine Al levels were assessed with ICP-MS. Laboratory quality control was performed using the certified reference materials of human hair, plasma, and urine.

RESULTS

Hair and urinary Al levels in obese subjects were significantly higher by 31% and 46% compared to the control levels, respectively. The presence of hypertension (41% cases), atherosclerosis (8%), type 2 diabetes mellitus (10%), and non-alcoholic fatty liver disease (NAFLD) (53%) in obese patients were not associated with Al levels in the studied subjects. An overall multiple regression model established urinary Al levels (β = 0.395; p < 0.001), hypertension (β = 0.331; p < 0.001) and NAFLD (β = 0.257; p = 0.003) were significantly and directly associated with BMI. Hair Al levels were found to be border-line significantly related to BMI after adjustment for several confounders (β = -0.205; p = 0.054).

CONCLUSIONS

Aluminium body burden is associated with increased body weight, although the causal relationship between Al exposure and obesity is not clear. Both clinical and experimental studies are required to further investigate the impact of Al exposure on metabolic parameters in obesity and especially direct effects of Al in adipose tissue.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Egg White Hydrolysate: A new putative agent to prevent vascular dysfunction in rats following long-term exposure to aluminum

Aluminum (Al) is toxic for humans and animals. Here, we have tested the potential for Egg White Hydrolysate (EWH) to protect against cardiovascular changes in rats exposed to both high and low dietary levels of Al. Indeed, EWH has been previously shown to improve cardio metabolic dysfunctions induced by chronic exposure to heavy metals. Male Wistar rats received orally: Group 1) Low aluminum level (AlCl₃ at a dose of 8.3 mg/kg b.w. during 60 days) with or without EWH treatment (1 g/kg/day); Group 2) High aluminum level (AlCl₃ at a dose of 100 mg/kg b.w. during 42 days) with or without EWH treatment. After Al treatment, rats co-treated with EWH did not show vascular dysfunction or increased blood pressure as was observed in non EWH-cotreated animals. Indeed, co-treatment with EWH prevented the following effects observed in both aorta and mesenteric arteries: the increased vascular responses to phenylephrine (Phe), the decreased ACh-induced relaxation, the reduction on endothelial modulation of vasoconstrictor responses and the nitric oxide bioavailability, as well as the increased reactive oxygen species production from NAD(P)H oxidase. Altogether, our results suggest that EWH could be used as a protective agent against the harmful vascular effects after long term exposure to Al.

Effect of aluminum (Al) speciation on erythrocytic antioxidant defense process: Correlations between lipid membrane peroxidation and morphological characteristics

Al contamination becomes a growing problem in human society. Accumulation of Al in blood could destroy the structure and disorder function of erythrocyte, and finally cause blood diseases. In the present study, AlCl₃ and Al(malt)₃ are respectively used in the erythrocyte system, in order to investigate the comparative toxic effect on erythrocyte fragility, the influence on cellular biochemical components and lipid peroxidation level. We find that the osmotic fragility, the number of Heinz bodies, the content of MDA and advanced oxidation protein product of the AlCl₃ treated erythrocytes were higher than the Al(malt)₃ treated erythrocytes at the same concentrations of Al(Ⅲ). The morphological and membrane protein changes of the AlCl₃ treated group show superior to the Al(malt)₃ treated group. In summary, we conclude that the comparative effect on the erythrocyte between organic aluminum and inorganic aluminum is significantly different, and the prime comparative difference between the toxic effects of both the compounds is oxidative stress. Further research should focus on in vivo experiments to confirm the differential toxicity and to elucidate the molecular mechanisms underlying Al-induced erythrocyte toxicity in order to prevent hematological disorders.

Aluminum exposure at human dietary levels promotes vascular dysfunction and increases blood pressure in rats: A concerted action of NAD(P)H oxidase and COX-2

Aluminum (Al) is a non-essential metal and a significant environmental contaminant and is associated with a number of human diseases including cardiovascular disease. We investigated the effects of Al exposure at doses similar to human dietary levels on the cardiovascular system over a 60day period. Wistar male rats were divided into two major groups and received orally: 1) Low aluminum level - rats were subdivided and treated for 60days as follows: a) Untreated - ultrapure water; b) AlCl₃ at a dose of 8.3mg/kg bw for 60days, representing human Al exposure by diet; and 2) High aluminum level - rats were subdivided and treated for 42days as follows: C) Untreated - ultrapure water; d) AlCl₃ at 100mg/kg bw for 42days, representing a high level of human exposure to Al. Effects on systolic blood pressure (SBP) and vascular function of aortic and mesenteric resistance arteries (MRA) were studied. Endothelium and smooth muscle integrity were evaluated by concentration-response curves to acetylcholine (ACh) and sodium nitroprusside. Vasoconstrictor responses to phenylephrine (Phe) in the presence and absence of endothelium and in the presence of the NOS inhibitor L-NAME, the potassium channels blocker TEA, the NAD(P)H oxidase inhibitor apocynin, superoxide dismutase (SOD), the non-selective COX inhibitor indomethacin and the selective COX-2 inhibitor NS 398 were analyzed. Vascular reactive oxygen species (ROS), lipid peroxidation and total antioxidant capacity, were measured. The mRNA expressions of eNOS, NAD(P)H oxidase 1 and 2, SOD1, COX-2 and thromboxane A2 receptor (TXA-2 R) were also investigated. Al exposure at human dietary levels impaired the cardiovascular system and these effects were almost the same as Al exposure at much higher levels. Al increased SBP, decreased ACh-induced relaxation, increased response to Phe, decreased endothelial modulation of vasoconstrictor responses, the bioavailability of nitric oxide (NO), the involvement of potassium channels on vascular responses, as well as increased ROS production from NAD(P)H oxidase and contractile prostanoids mainly from COX-2 in both aorta and mesenteric arteries. Al exposure increased vascular ROS production and lipid peroxidation as well as altered the antioxidant status in aorta and MRA. Al decreased vascular eNOS and SOD1 mRNA levels and increased the NAD(P)H oxidase 1, COX-2 and TXA-2 R mRNA levels. Our results point to an excess of ROS mainly from NAD(P)H oxidase after Al exposure and the increased vascular prostanoids from COX-2 acting in concert to decrease NO bioavailability, thus inducing vascular dysfunction and increasing blood pressure. Therefore, 60-day chronic exposure to Al, which reflects common human dietary Al intake, appears to pose a risk for the cardiovascular system.

Increased Serum Al Levels in Hemodialysis Patients Kept Enhanced during a 2-Year Prospective Study

The regulation of mineral homeostasis is altered in hemodialysis patients with renal insufficiency, producing increased risk for secondary diseases like cardiovascular ones. We hypothesized that risen serum aluminum (Al) concentration in hemodialysis patients kept enhanced during a 2-year longitudinal study is associated with enhanced cardiovascular risk and influenced by medical treatments. This study reports the prospective monitoring of serum Al levels in six-monthly samplings over 2 years in 116 hemodialysis patients and a control group of 50 healthy adults. The influence of other factors like sex, age, kidney transplant, disease etiology, and drug consumption was also considered. At each sampling, serum Al levels were significantly higher in the patients than in the healthy controls (P < 0.05). Levels in the patient group were statistically significantly lower at the third and fourth versus first and second samplings, which may be related to Al accumulation in tissues. Increased Al levels in patients were positively and significantly related to serum calcium (Ca) and uric acid levels. Serum Al concentrations were significantly lower in patients receiving vasodilators and diuretics. Higher serum Al levels in hemodialyzed patients administered with phosphate binders or anti-hyperkalemics are attributable to their usual Al salt content. The consumption of antianemic drugs increases Al absorption by forming more bioavailable complexes with the compounds in these drugs. In conclusion, this is the first study to indicate that cardiovascular problems associated with elevated serum Al levels in hemodialysis patients may be in part mitigated by administrating vasodilators and diuretics, which reduce these levels.

Role of Spirulina in mitigating hemato-toxicity in Swiss albino mice exposed to aluminum and aluminum fluoride

Aluminum is ingested through foods, water, air, and even drugs. Its intake is potentiated further through foods and tea prepared in aluminum utensils and Al salt added in the drinking water for removal of suspended impurities and also fluoride in the affected areas. The ameliorating role of a blue green alga Spirulina is well documented to various pollutants in the animal models. We, therefore, examined its protective role (230 mg/kg body weight) on the hematology of male Swiss albino mice treated with aluminum (sub-acute = 78.4 mg/kg body weight for 7 days, sub-chronic = 7.8 mg/kg body weight for 90 days) and aluminum fluoride (sub-acute = 103 mg/kg body weight, sub-chronic = 21 mg/kg body weight), along with their recovery after 90 days of sub-chronic exposure. This study revealed significant reduction in the values of RBC (5-18 %), Hb (15-17 %), PCV (8-14 %), and platelets (26-36 %), and increase in WBC (54-124 %) in the treated mice, particularly after sub-acute exposure. Aluminum fluoride was comparatively more toxic than aluminum. Further, Spirulina supplement not only alleviated toxicity of test chemicals in Swiss albino mice but also led to their better recovery after withdrawal.