Association of individual and combined exposures of 10 metals with periodontitis: Results from a large population-based study

AIMS

To systematically investigate the association between individual and combined metal exposure and periodontitis.

METHODS

Data encompassing complete periodontal examinations and metal detection in blood and urine samples were procured from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Three statistical methods, namely weighted logistic regression, Bayesian kernel machine regression (BKMR), and weighted quantile sum (WQS) regression, were used to evaluate the independent and combined associations between metals and periodontitis.

RESULTS

Elevated concentrations of blood cadmium (odds ratio [OR]: 1.73, 95% confidence interval [CI]: 1.15-2.61) and blood lead (OR: 1.17, 95 %CI: 1.02-1.34) exhibited a positive association with periodontitis, even after adjusting for potential confounding factors. The BKMR and WQS regression suggested that the co-exposure of metals was also positively associated with periodontitis. Moreover, estradiol and albumin were identified as potential mediators in the relationship between the WQS index of the 10 metals in blood and periodontitis explaining 25.36% and 2.02% of the relationship, respectively. Furthermore, generally consistent patterns of associations between metals and periodontitis and mediating roles of estrogen and albumin were observed after a series of sensitivity analyses.

CONCLUSION

This study provides evidence of positive associations between elevated levels of cadmium, lead or metal mixture and periodontitis, which may be partially mediated by sex hormones and oxidative stress indicators.

Mixed uremic osteodystrophy: an ill-described common bone pathology in patients with chronic kidney disease

Renal osteodystrophy (ROD) starts early and progresses with further loss of kidney function in patients with chronic kidney disease (CKD). There are four distinct types of ROD based on undecalcified bone biopsy results. Adynamic bone disease and osteomalacia are the predominant forms of low bone turnover, while hyperparathyroid bone disease and mixed uremic osteodystrophy (MUO) are typically associated with high bone turnover. MUO is a prevalent but poorly described pathology that demonstrates evidence of osteomalacia on top of the high bone formation/resorption. The prevalence of MUO ranges from 5 to 63% among different studies. The pathogenesis of MUO is multi-factorial. Altered phosphate homeostasis, hypocalcemia, vitamin D deficiency, increased FGF-23, interleukins 1 and 6, TNF-α, amyloid, and heavy metal accumulation are the main inducers of MUO. The clinical findings of MUO are usually non-specific. The use of non-invasive testing such as bone turnover markers and imaging techniques might help to suspect MUO. However, it is usually impossible to precisely diagnose this condition without performing bone biopsy. The principal management of MUO is to control the maladaptive hyperparathyroidism along with correcting any nutritional mineral deficiencies that may induce mineralization defect. MUO is a common but still poorly understood bone pathology category; it demonstrates the complexity and difficulty in understanding ROD. A large prospective bone biopsy-based studies are needed for better identification as proper diagnosis and management would improve the outcome of patients with MUO.

Vitamin D and calcium co-therapy mitigates pre-established cadmium nephropathy by regulating renal calcium homeostatic molecules and improving anti-oxidative and anti-inflammatory activities in rat

BACKGROUND

Cadmium (Cd) is a major environmental pollutant and chronic toxicity could induce nephropathy by increasing renal oxidative stress and inflammation. Although vitamin D (VD) and calcium (Ca) prophylactic treatments attenuated Cd-induced cell injury, none of the prior studies measure their renoprotective effects against pre-established Cd-nephropathy.

AIMS

To measure the alleviating effects of VD and/or Ca single and dual therapies against pre-established nephrotoxicity induced by chronic Cd toxicity prior to treatment initiation.

METHODS

Forty male adult rats were allocated into: negative controls (NC), positive controls (PC), Ca, VD and VC groups. The study lasted for eight weeks and all animals, except the NC, received CdCl₂ in drinking water (44 mg/L) throughout the study. Ca (100 mg/kg) and/or VD (350 IU/kg) were given (five times/week) during the last four weeks to the designated groups. Subsequently, the expression of transforming growth factor-β (TGF-β1), inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), VD synthesising (Cyp27b1) and catabolizing (Cyp24a1) enzymes with VD receptor (VDR) and binding protein (VDBP) was measured in renal tissues. Similarly, renal expression of Ca voltage-dependent channels (Ca_V1.1/Ca_V3.1), store-operated channels (RyR1/ITPR1), and binding proteins (CAM/CAMKIIA/S100A1/S100B) were measured. Serum markers of renal function alongside several markers of oxidative stress (MDA/H₂O₂/GSH/GPx/CAT) and inflammation (IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 were also measured.

RESULTS

The PC group exhibited hypovitaminosis D, hypocalcaemia, hypercalciuria, proteinuria, reduced creatinine clearance, and increased renal apoptosis/necrosis with higher caspase-3 expression. Markers of renal tissue damage (TGF-β1/iNOS/NGAL/KIM-1), oxidative stress (MDA/H₂O₂), and inflammation (TNF-α/IL-1β/IL-6) increased, whilst the antioxidants (GSH/GPx/CAT) and IL-10 decreased, in the PC group. The PC renal tissues also showed abnormal expression of Cyp27b1, Cyp24a1, VDR, and VDBP, alongside Ca-membranous (Ca_V1.1/Ca_V3.1) and store-operated channels (RyR1/ITPR1) and cytosolic Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B). Although VD was superior to Ca monotherapy, their combination revealed the best mitigation effects by attenuating serum and renal tissue Cd concentrations, inflammation and oxidative stress, alongside modulating the expression of VD/Ca-molecules.

CONCLUSIONS

This study is the first to show improved alleviations against Cd-nephropathy by co-supplementing VD and Ca, possibly by better regulation of Ca-dependent anti-oxidative and anti-inflammatory actions.

OUP accepted manuscript

Background

Cadmium (Cd) is a highly toxic heavy metal that adversely affects both human and animal health. Chronic cadmium exposure causes serious kidney damage. The current study investigated the protective role of cerium oxide nanoparticles (CeO₂NPs) against cadmium chloride (CdCl₂)-induced renal injury.

Method

One hundred and twenty male albino rats were divided into 6 equal groups. Group (C): considered as control group which was given distilled water orally. Group (NC_.1 and NC_.5): rats were injected i.p. with nanoceria at a dose of (0.1 and 0.5 mg/kg b.wt), respectively, twice a week for 2 weeks starting at the 15th day of the study. Group (Cd): rats were received CdCl₂ orally (10 mg/kg b.wt) daily for 28 days. Groups (Cd + NC_.1 and Cd + NC_.5): rats were given CdCl₂ orally (10 mg/kg b.wt) for 28 days and CeO₂NPs by i.p. injection at a dose of (0.1 and 0.5 mg/kg b.wt), respectively, twice a week for 2 weeks started at the 15th day of the experiment.

Results

The Cd group exhibited a significant increase in the serum levels of IL-1β, KIM-1, Cys-C, and β2-MG, downregulation of the antioxidant initiator genes such as Nrf-2, and up-regulation of apoptosis markers such as nibrin gene (NBN). Urine examination showed a high level of microalbuminuria, abnormal physical, chemical, and microscopical changes in comparison with control groups.

Conculsion

Remarkably, posttreatment with CeO₂NPs showed significant improvement in kidney histopathological picture and relieved the alterations in kidney biomarkers, inflammatory markers, urine abnormalities, and expressions of different genes as Nrf-2 and NBN.

Cadmium toxicity: A role in bone cell function and teeth development

Cadmium (Cd) is a widespread environmental contaminant that causes severe bone metabolism disease, such as osteoporosis, osteoarthritis, and osteomalacia. The present review aimed to explore the molecular mechanisms of Cd-induced bone injury starting from bone cell function and teeth development. Cd inhibits the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts, and directly causes BMSC apoptosis. In the case of osteoporosis, Cd mainly affects the activation of osteoclasts and promotes bone resorption. Cd-induces osteoblast injury and oxidative stress, which causes DNA damage, mitochondrial dysfunction, and endoplasmic reticulum stress, resulting in apoptosis. In addition, the development of osteoarthritis (OA) might be related to Cd-induced chondrocyte damage. The high expression of metallothionein (MT) might reduce Cd toxicity toward osteocytes. The toxicity of Cd toward teeth mainly focuses on enamel development and dental caries. Understanding the effect of Cd on bone cell function and teeth development could contribute to revealing the mechanisms of Cd-induced bone damage. This review explores Cd-induced bone disease from cellular and molecular levels, and provides new directions for removing this heavy metal from the environment.

Toxicological approaches for the quantitative inhalation risk assessment of toxic metals from tobacco smoke: application on the deterministic and probabilistic inhalation risk assessment of cadmium for Austrian smokers

OBJECTIVE

The objective of this study was the assessment of risks from inhalation exposure of Austrian smokers to cadmium through established toxicological approaches with emphasis on the exposure assessment component, which is challenging regarding the actual amount of metal that is inhaled and the simulation of the smoking pattern.

MATERIALS AND METHODS

Exposure assessment comprised an estimation of the proportion of cadmium inhaled through smoking and actual occurrence data in tobacco products and survey smoking habits, which were integrated in alternative scenarios through a deterministic and a probabilistic Monte Carlo simulation method. Risks were characterized through the comparison of the exposure with health-based guidance values, as well as through the assessment of the excess lifetime cancer risk (ELCR), the non-cancer hazard quotient (NCHQ), and the margin of exposure (MOE). The strengths, the uncertainties, and the limitations of the different methodologies were discussed.

RESULTS AND DISCUSSION

Upper exposures are close or exceed the Permitted Daily Exposure. Respiratory ELCRs are unacceptable compared to the benchmark range of 1.0E-06 to 1.0E-04. Renal and respiratory NCHQs exceed the target value of 1.0 by 3- to 17-fold. MOEs are not protective enough for cancer and non-cancer effects. The amount of cadmium that reaches the lung is a key source of uncertainty.

CONCLUSION

Probabilistic estimates provide a refined capture of the actual inhalation exposure. Risk estimates and gender and age profiles are alarming, especially for young smokers. Application of toxicological approaches, combined with realistic assessment of the inhalation exposure levels, can support risk communication and management.

Vitamin D3 and calcium cosupplementation alleviates cadmium hepatotoxicity in the rat: Enhanced antioxidative and anti-inflammatory actions by remodeling cellular calcium pathways

Although vitamin D (VD) and calcium (Ca) attenuate cadmium (Cd) metabolism, their combined antioxidant and anti-inflammatory actions against Cd toxicity have not been previously explored. Hence, this study measured the protective effects of VD ± Ca supplements against Cd hepatotoxicity. Forty adult male rats were distributed to: negative controls (NCs), positive controls (PCs), VD, Ca, and VD₃ and Ca (VDC) groups. All groups, except NC, received CdCl₂ in drinking water (44 mg/L) for 4 weeks individually or concurrently with intramuscular VD₃ (600 IU/kg; three times per week) and/or oral Ca (100 mg/kg; five times per week). The PC group showed abnormal hepatic biochemical parameters and increase in cellular cytochrome C, caspase-9, and caspase-3 alongside the apoptotic/necrotic cell numbers by terminal deoxynucleotidyl transferase dUTP nick end labeling technique. The PC hepatic tissue also had substantially elevated pro-oxidants (malondialdehyde [MDA]/H₂ O₂ /protein carbonyls) and inflammatory cytokines (interleukin 1β [IL-1β]/IL-6/IL17A/tumor necrosis factor-α), whereas the anti-inflammatory (IL-10/IL-22) and antioxidants (glutathione [GSH]/GPx/catalase enzyme [CAT]) markers declined. Hypovitaminosis D, low hepatic tissue Ca, aberrant hepatic expression of VD-metabolizing enzymes (Cyp2R1/Cyp27a1/cyp24a1), receptor and binding protein alongside Ca-membrane (Ca_V 1.1/Ca_V 3.1), and store-operated (RyR1/ITPR1) channels, and Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B) were observed in the PC group. Both monotherapies decreased serum, but not tissue Cd levels, restored the targeted hepatic VD/Ca molecules' expression. However, these effects were more prominent in the VD group than the Ca group. The VDC group, contrariwise, disclosed the greatest alleviations on serum and tissue Cd, inflammatory and oxidative markers, the VD/Ca molecules and tissue integrity. In conclusion, this report is the first to reveal boosted protection for cosupplementing VD and Ca against Cd hepatotoxicity that could be due to enhanced antioxidative, anti-inflammatory, and modulation of the Ca pathways.

Stabilization of Vitamin D in Pea Protein Isolate Nanoemulsions Increases Its Bioefficacy in Rats

Micronutrient delivery formulations based on nanoemulsions can enhance the absorption of nutrients and bioactives, and thus, are of great potential for food fortification and supplementation strategies. The aim was to evaluate the bioefficacy of vitamin D (VitD) encapsulated in nanoemulsions developed by sonication and pH-shifting of pea protein isolate (PPI) in restoring VitD status in VitD-deficient rats. Weaned male albino rats (n = 35) were fed either normal diet AIN-93G (VitD 1000 IU/kg) (control group; n = 7) or a VitD-deficient diet (<50 IU/kg) for six weeks (VitD-deficient group; n = 28). VitD-deficient rats were divided into four subgroups (n = 7/group). Nano-VitD and Oil-VitD groups received a dose of VitD (81 µg) dispersed in either PPI-nanoemulsions or in canola oil, respectively, every other day for one week. Their control groups, Nano-control and Oil-control, received the respective delivery vehicles without VitD. Serum 25-hydroxyvitamin D [25(OH)VitD], parathyroid hormone (PTH), Ca, P, and alkaline phosphatase (ALP) activity were measured. After one week of treatment, the VitD-deficient rats consuming Nano-VitD recovered from Vitamin D deficiency (VDD) as compared against baseline and had serum 25(OH)VitD higher than the Nano-control. Enhancement in VitD status was followed with expected changes in serum PTH, Ca, P, and ALP levels, as compared against the controls. Stabilization of VitD within PPI-based nanoemulsions enhances its absorption and restores its status and biomarkers of bone resorption in VitD-deficient rats.

The association between serum vitamin D levels and renal tubular dysfunction in a general population exposed to cadmium in China

Cadmium exposure can cause renal tubular dysfunction. Recent studies show that vitamin D can play multiple roles in the body. However, the association between serum vitamin D levels and renal tubular dysfunction in a general population exposed to cadmium has not been clarified. We performed study to assess the effects of cadmium on serum 25(OH) D levels and the association between serum 25(OH) D levels and renal tubular dysfunction in a population environmentally exposed to cadmium. A total of 133 subjects living in control area and two cadmium polluted areas were included in the present study. Cadmium in urine (UCd) and blood (BCd), urinary β2Microglobulin (UBMG), urinary retinol binding protein (URBP) and serum 25 (OH) D were determined. Logistic regression was used to estimate the association between 25 (OH) D and prevalence of renal tubular dysfunction. No significant differences were observed in serum 25(OH) D levels among the four quartile of UCd and BCd after adjusting with cofounders. After adjusted with the confounders, the odds ratio (OR) of subjects with 25(OH) D ≥ 40 ng/ml were 0.20 (95%CI: 0.1–0.8) if UBMG was chosen as indicators of renal dysfunction and 0.28 (95%CI: 0.1–1.1) if URBP was chosen as indicators of renal dysfunction, compared with those with 25(OH) D < 30 ng/ml, respectively. Similar results were observed in those subjects living in cadmium polluted areas or with high level of UCd or BCd. Our data indicated that cadmium exposure did not affect serum 25(OH) D level and high 25 (OH) D levels were associated with a decreased risk of renal tubular dysfunction induced by cadmium.

Changes in Trace Element Contents and Morphology in Bones of Duck Exposed to Molybdenum or/and Cadmium

Cadmium (Cd) and high molybdenum (Mo) can lead to adverse reactions on animals, but the coinduced toxicity of Mo and Cd to bone in ducks was not well understood. The objective of this study was to investigate the changes in trace elements' contents and morphology in bones of duck exposed to Mo or/and Cd. One hundred twenty healthy 11-day-old male ducks were randomly divided into six groups and treated with commercial diet containing Cd or/and Mo. On the 60th and 120th days, the blood, excretion, and metatarsals were collected to determine alkaline phosphatase (ALP) activity and the contents of Mo, Cd, calcium (Ca), phosphorus (P), copper (Cu), iron (Fe), zine (Zn), and selenium (Se). In addition, metatarsals were subjected to histopathological analysis with the optical microscope and radiography. The results indicated that Mo and Cd contents significantly increased while Ca, P, Cu, and Se contents remarkably decreased in metatarsals in coexposure groups (P < 0.01). Contents of Fe and Zn in metatarsals had no significant difference among groups (P > 0.05). Ca content in serum had no significant difference among experimental groups (P > 0.05), but P content was significantly decreased in HMo and HMo + Cd groups (P < 0.05). Contents of Ca and P in excretion and ALP activity were significantly increased in coinduced groups (P < 0.05). Furthermore, osteoporotic lesions, less and thinner trabecular bone were observed in combination groups. The findings suggested that dietary of Cd or/and Mo could lead to bone damages in ducks via disturbing the balance of Ca and P in body and homeostasis of Cu, Fe, Zn, and Se in bones; moreover, the two elements showed a possible synergistic relationship.

Effects of thirty elements on bone metabolism

The human skeleton, made of 206 bones, plays vital roles including supporting the body, protecting organs, enabling movement, and storing minerals. Bones are made of organic structures, intimately connected with an inorganic matrix produced by bone cells. Many elements are ubiquitous in our environment, and many impact bone metabolism. Most elements have antagonistic actions depending on concentration. Indeed, some elements are essential, others are deleterious, and many can be both. Several pathways mediate effects of element deficiencies or excesses on bone metabolism. This paper aims to identify all elements that impact bone health and explore the mechanisms by which they act. To date, this is the first time that the effects of thirty minerals on bone metabolism have been summarized.

Hepatoprotective activity of Moringa oleifera against cadmium toxicity in rats

Aim:

The present investigation has been conducted to evaluate the hepatoprotective activity of Moringa oleifera against cadmium-induced toxicity in rats.

Materials and Methods:

For this study, 18 Wistar albino rats were taken. Control group, Group I rats were given cadmium chloride @ 200 ppm per kg and Group II rats were treated with M. oleifera extract @ 500 mg/kg along with cadmium chloride @ 200 ppm per kg (daily oral for 28 days). On 29^th day, animals were slaughtered and various parameters were determined. Serum biomarkers, oxidative stress parameters, histomorphological examination were carried out with estimation of cadmium concentration in liver tissues.

Results:

Oral administration of cadmium chloride @ 200 ppm/kg for 28 days resulted in a significant increase in aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), significant (p≤0.01) increase of lipid peroxidation (LPO) and decrease in superoxide dismutase (SOD), and increase in cadmium accumulation in liver. Treatment with M. oleifera @ 500 mg/kg significantly (p<0.01) decreased the elevated ALP, AST, ALT, LPO levels and increase in SOD levels, and as compared to cadmium chloride treated group. However, there was no significant difference in cadmium concentration in liver when compared with cadmium chloride treated group.

Conclusion:

The study conclude that supplementation of M. oleifera (500 mg/kg), daily oral for 28 days has shown protection against cadmium-induced hepatotoxicity.

Diet and nutrients are contributing factors that influence blood cadmium levels

Studies suggested the intake of Cd from diet can be approximately equivalent to that from smoking. Moreover, a mutual metabolic influence between Cd and nutrients has been reported. The purpose of this study was to evaluate the relationship between blood cadmium concentration (BCdC) and food consumption, nutrients intake (Ca, Fe, Zn, vitamin C, and vitamin D), tobacco smoking, and some other variables (age, body mass index, and residence) in 243 adults living in the Italian island of Sardinia (Sassari Province). Specifically, we hypothesized that offal consumption contributes to Cd intakes and blood levels. The BCdC was quantified by graphite furnace atomic absorption spectrometry, and information on personal data was collected through questionnaires. Smoke significantly contributed to the BCdC (P < .001). Nonsmoker subjects who eat offal showed significantly higher BCdC (P = .04). Moreover, slightly higher BCdCs were also observed in nonsmoker subjects who eat rice, fish, and bread. The BCdC positively correlated with age of subjects (r = 0.144; P = .025) and offal daily intake in nonsmokers (r = 0.393; P < .001). The intake of Ca was negatively correlated (r = -0.281; P = .001) with the BCdC in females. The multiple linear regression analysis showed smoking > consumption of offal > body mass index ≈ age as the most important risk factors for the BCdC in the selected population.