Hexavalent chromium exposure alters bone remodeling in the developing tooth alveolus and delays tooth eruption

Although it has been demonstrated that exposure of lactating rats to CrVI delays tooth eruption, the effects of CrVI exposure on bone remodeling in the developing alveolus during tooth eruption remain unknown. Our purpose was to analyze the effect of CrVI in the alveolus of the first lower molar of rats. Thirty-two suckling Wistar rats were divided into two groups. The experimental group received 12.5 mg/kg body weight/day of potassium dichromate dissolved in saline solution by oral gavage as of day 4 of the experiment; the control group received an equal dose of saline solution. Each group was divided into two sub-sets and euthanized at the ages of 9 and 15 days, respectively. Histochemical and histomorphometric studies of the bone surfaces of the developing tooth alveolus were performed. The percentage of bone formation surfaces was lower in experimental animals than in age-matched controls. The percentage of bone resorption surfaces was significantly lower in 9-day-old experimental rats than in controls and significantly higher in 15-day-old experimental rats than in controls. Exposure to CrVI during lactation alters the sequence of bone resorption and formation in the walls of the developing alveolus, both of which are necessary for tooth eruption, thus causing a delay.

Chromium Genotoxicity associated with Respiratory Disease

Chromium existing in the biosphere in prominent two forms Cr (III) and Cr (VI) is a well-studied heavy metal. Cr (III) is considered as non-harmful and necessary element in diet whereas Cr(VI) is extremely toxic exerting various negative health impacts on human and other organisms. Mining activity is must for extracting economic minerals and a large number of people are related to these sites as worker or habitants and a major source of chromium exposure. Present chapter discusses genotoxic nature of chromium considering respiratory disease resulted from chromium exposure. The genotoxicity is illustrated in terms of chromium induced differential expressed genes (DEGs), transcription factors and microRNA regulating the DEGs and their gene ontology.

Phytoremediation using Phyllostachys pubescens (Moso Bamboo) to reduce the risk of chromium exposure

In this study, a bamboo species, the Phyllostachys pubescens – Moso Bamboo (MB) -, was selected for its heavy metals accumulation and translocation potential to restore Cr-contaminated soil. In order to evaluate the potential for phytoremediation using MB to restore Cr-contaminated soil, pot experiments were carried out in simulated Mediterranean conditions, in laboratory, in a controlled environment, at a temperature of 20°C. Cr removal from soil was 43 % starting from a Cr content of approx. 200 mg/kg Dry Weight and the quantity of Cr per gram of root and rhizome was equal to 1.31 mg/g dw, while the quantity of Cr per gram of stem and leaves was equal to 0.86 mg/g dw, after 12 weeks. Pot experiments confirm that phytoremediation using plants such as MB provides an alternative approach for handling Cr-contaminated soil.

Drinking water heavy metal toxicity and chronic kidney diseases: a systematic review

Heavy metals in drinking water can threat human health and may induce several diseases. The association between heavy metals exposure and chronic kidney disease (CKD) has been indicated by few epidemiological studies. We conducted a systematic review of the epidemiologic publications of the association between exposure to heavy metals through drinking water and CKD. Keywords related to heavy metals and kidney diseases on MeSH were identified and searched in PubMed, Google Scholar, Scopus, Ovid-Medline and Web of Science until July 2020. 14 publications met our inclusion criteria and included in the current review. The included articles were conducted on the association between arsenic, cadmium, lead and chromium in drinking water and CKD. Our study could not find strong evidence between heavy exposure to through drinking water and CKD, except for arsenic. The negative association was found between arsenic and lead and glomerular filtration rate (eGFR). The positive correlation was observed between cadmium exposure and urinary N-acetyl-β-d-glucosaminidase (NAG) concentrations, and also arsenic and chromium exposure and kidney injury molecule (KIM-1). Assessment of studies showed an association between arsenic, cadmium, lead and chromium and albuminuria and proteinuria, without CKD outcomes. Current systematic study showed few evidence for exposure to arsenic, cadmium, lead and chromium through drinking water and incidence of kidney problems. However, more epidemiological studies are required to confirm this association.