Effect of Oral Aluminum Chloride Administration During Lactation on Short and Long-Term Memory of Their Offspring

Developmental Exposure to Aluminum Chloride Irreversibly Affects Postnatal Hippocampal Neurogenesis Involving Multiple Functions in Mice

Aluminum (Al) is neurotoxic to adults and also to infants. In this study, we investigated the developmental exposure effect of AlCl3 on postnatal hippocampal neurogenesis. Pregnant mice were administered 0-, 900-, or 1800-ppm AlCl3 via drinking water from gestational day 6 to postnatal day (PND) 21, with their offspring examined on PND 21 and PND 77. On PND 21, GFAP-immunoreactive (+) neural stem cells (NSCs) and p21Cip1/Waf1+ cells were decreased in number in the subgranular zone at 900 and ≥900 ppm, respectively. Pcna transcript level examined at 1800 ppm was decreased in the dentate gyrus. These results suggest induction of compromised cell quiescence that caused impaired self-renewal capacity of NSCs accompanying slowing down of cell cycling, which ultimately resulted in exhaustion of the NSC pool. At 1800 ppm, Reelin+ hilar GABAergic interneurons were also decreased, suggesting a contribution to the NSC reduction. At this dose, TBR2+ or DCX+ progenitor and immature granule cells and PVALB+ interneurons were increased. Moreover, COX-2+ granule cells were increased at ≥900 ppm. These results suggest facilitation of transient progenitor cell proliferation and differentiation during exposure. Moreover, TUNEL+ or Morin-stained granule cells were increased, together with Casp12 transcript upregulation, suggesting induction of Al accumulation-related endoplasmic reticulum stress-mediated granule cell apoptosis. Transcript expression changes on cholinergic and glutamatergic signals and synaptic plasticity suggested contribution to disruptive neurogenesis. The NSC-targeting effects sustained through the adult stage despite no sustained Al-accumulation. These results suggest that developmental AlCl3-exposure irreversibly affects postnatal hippocampal neurogenesis involving multiple functions in mice.

Potential application of glycerol in the production of plant beneficial microorganisms

This review highlights the importance of research for development of biofertilizer and biocontrol products based on the use of glycerol for further process scale-up to industrial microbiology. Glycerol can be used successfully in all stages of production of plant beneficial microorganisms. It serves as an excellent substrate in both submerged and solid-state fermentation processes with free and immobilized microbial cells. Glycerol is also one of the most attractive formulation agents that ensures high cell density and viability including in harsh environmental conditions. Future research is discussed to make this inexpensive material a base for industrial production of plant beneficial microorganisms.

Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts

Abstract Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007) . Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of "total Al"assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al(+3) to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)(+2) and Al(H2O)6 (+3)] that after complexation with O2(•-), generate Al superoxides [Al(O2(•))](H2O5)](+2). Semireduced AlO2(•) radicals deplete mitochondrial Fe and promote generation of H2O2, O2 (•-) and OH(•). Thus, it is the Al(+3)-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer's disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances.

Spectral changes of brain activity in rat offspring exposed to aluminium during gestation and lactation

Exposure to aluminium during gestation causes changes in mammalian brain development and behavior. Our aim was to perform spectral analysis on electrocortical activity of Sprague Dawley male pups (30?3 days of age) whose mothers were treated with aluminium during gestation and lactation. There was a higher presence of power spectra in the delta range of parietal electrocortical activity, a lower presence in the theta range and increased values of the parameter DT as the ratio of delta to theta range in pups indirectly exposed to aluminium (whose mothers were drinking a 0.5% water solution of aluminium chloride during the gestation and lactation periods), compared to controls.