Current Review of Increasing Animal Health Threat of Per- and Polyfluoroalkyl Substances (PFAS): Harms, Limitations, and Alternatives to Manage Their Toxicity

Perfluorinated and polyfluorinated alkyl substances (PFAS), more than 4700 in number, are a group of widely used man-made chemicals that accumulate in living things and the environment over time. They are known as "forever chemicals" because they are extremely persistent in our environment and body. Because PFAS have been widely used for many decades, their presence is evident globally, and their persistence and potential toxicity create concern for animals, humans and environmental health. They can have multiple adverse health effects, such as liver damage, thyroid disease, obesity, fertility problems, and cancer. The most significant source of living exposure to PFAS is dietary intake (food and water), but given massive industrial and domestic use, these substances are now punctually present not only domestically but also in the outdoor environment. For example, livestock and wildlife can be exposed to PFAS through contaminated water, soil, substrate, air, or food. In this review, we have analyzed and exposed the characteristics of PFAS and their various uses and reported data on their presence in the environment, from industrialized to less populated areas. In several areas of the planet, even in areas far from large population centers, the presence of PFAS was confirmed, both in marine and terrestrial animals (organisms). Among the most common PFAS identified are undoubtedly perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), two of the most widely used and, to date, among the most studied in terms of toxicokinetics and toxicodynamics. The objective of this review is to provide insights into the toxic potential of PFAS, their exposure, and related mechanisms.

Poisonous Plants of the Genus Pimelea: A Menace for the Australian Livestock Industry

Pimelea is a genus of about 140 plant species, some of which are well-known for causing animal poisoning resulting in significant economic losses to the Australian livestock industry. The main poisonous species/subspecies include Pimelea simplex (subsp. simplex and subsp. continua), P. trichostachya and P. elongata (generally referred to as Pimelea). These plants contain a diterpenoid orthoester toxin, called simplexin. Pimelea poisoning is known to cause the death of cattle (Bos taurus and B. indicus) or weaken surviving animals. Pimelea species are well-adapted native plants, and their diaspores (single seeded fruits) possess variable degrees of dormancy. Hence, the diaspores do not generally germinate in the same recruitment event, which makes management difficult, necessitating the development of integrated management strategies based on infestation circumstances (e.g., size and density). For example, the integration of herbicides with physical control techniques, competitive pasture establishment and tactical grazing could be effective in some situations. However, such options have not been widely adopted at the field level to mitigate ongoing management challenges. This systematic review provides a valuable synthesis of the current knowledge on the biology, ecology, and management of poisonous Pimelea species with a focus on the Australian livestock industry while identifying potential avenues for future research.

New perspectives in application of kidney biomarkers in mycotoxin induced nephrotoxicity, with a particular focus on domestic pigs

The gradual spread of Aspergilli worldwide is adding to the global shortage of food and is affecting its safe consumption. Aspergillus-derived mycotoxins, including aflatoxins and ochratoxin A, and fumonisins (members of the fusariotoxin group) can cause pathological damage to vital organs, including the kidney or liver. Although the kidney functions as the major excretory system in mammals, monitoring and screening for mycotoxin induced nephrotoxicity is only now a developmental area in the field of livestock feed toxicology. Currently the assessment of individual exposure to mycotoxins in man and animals is usually based on the analysis of toxin and/or metabolite contamination in the blood or urine. However, this requires selective and sensitive analytical methods (e.g., HPLC-MS/MS), which are time consuming and expensive. The toxicokinetic of mycotoxin metabolites is becoming better understood. Several kidney biomarkers are used successfully in drug development, however cost-efficient, and reliable kidney biomarkers are urgently needed for monitoring farm animals for early signs of kidney disease. β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are the dominant biomarkers employed routinely in environmental toxicology research, while kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as effective markers to identify mycotoxin induced nephropathy. Pigs are exposed to mycotoxins due to their cereal-based diet and are particularly susceptible to Aspergillus mycotoxins. In addition to commonly used diagnostic markers for nephrotoxicity including plasma creatinine, NAG, KIM-1 and NGAL can be used in pigs. In this review, the currently available techniques are summarized, which are used for screening mycotoxin induced nephrotoxicity in farm animals. Possible approaches are considered, which could be used to detect mycotoxin induced nephropathy.

Evaluation of animal toxicity studies with diisocyanates regarding presence of thresholds for induction and elicitation of respiratory allergy by quantitative weight of evidence

Animal toxicity studies on diisocyanates were evaluated using quantitative weight of evidence (QWoE) to test the hypothesis that the dose-response curve shows a threshold for the induction and/or elicitation of respiratory sensitization. A literature search identified 59 references that included at least two concentration groups of the diisocyanate and a vehicle-exposed concurrent control in the study design. These studies were subjected to a QWoE-assessment applying scoring criteria for quality and relevance/strength of effects relevant to the selected endpoint of respiratory sensitization. Overall, the studies assessing dose/concentration-response for diisocyanates with the endpoint, respiratory sensitization, were heterogenous regarding study design, animal models used, endpoints assessed, and quality. Only a limited number of the studies subjected to the QWoE-assessment allowed drawing conclusions about possible thresholds for respiratory sensitization. Highest quality and relevance/strength of effects scores were obtained by a series of studies specifically designed to investigate a potential threshold for elicitation of respiratory sensitization in the Brown Norway (BN) rat. These studies applied an elaborate study design to optimize induction of respiratory sensitization and reduce interference by respiratory tract irritation. In summary, the available studies provided moderate to good support for the existence of a threshold for elicitation and limited to moderate support for a threshold regarding induction of respiratory allergy by diisocyanates in experimental animals. However, a quantitative extrapolation of threshold values established in rodents to humans remains complex.

Facile Preparation of WO3-x Dots with Remarkably Low Toxicity and Uncompromised Activity as Co-reactants for Clinical Diagnosis by Electrochemiluminescence

The exceptional nature of WO_3-x dots has inspired widespread interest, but it is still a significant challenge to synthesize high-quality WO_3-x dots without using unstable reactants, expensive equipment, and complex synthetic processes. Herein, the synthesis of ligand-free WO_3-x dots is reported that are highly dispersible and rich in oxygen vacancies by a simple but straightforward exfoliation of bulk WS₂ and a mild follow-up chemical conversion. Surprisingly, the WO_3-x dots emerged as co-reactants for the electrochemiluminescence (ECL) of Ru(bpy)₃ ²⁺ with a comparable ECL efficiency to the well-known Ru(bpy)₃ ²⁺ /tripropylamine (TPrA) system. Moreover, compared to TPrA, whose toxicity remains a critical issue of concern, the WO_3-x dots were ca. 300-fold less toxic. The potency of WO_3-x dots was further explored in the detection of circulating tumor cells (CTCs) with the most competitive limit of detection so far.

Of poisons and parasites-the defensive role of tetrodotoxin against infections in newts

Classical research on animal toxicity has focused on the role of toxins in protection against predators, but recent studies suggest these same compounds can offer a powerful defense against parasites and infectious diseases. Newts in the genus Taricha are brightly coloured and contain the potent neurotoxin, tetrodotoxin (TTX), which is hypothesized to have evolved as a defense against vertebrate predators such as garter snakes. However, newt populations often vary dramatically in toxicity, which is only partially explained by predation pressure. The primary aim of this study was to evaluate the relationships between TTX concentration and infection by parasites. By systematically assessing micro- and macroparasite infections among 345 adult newts (sympatric populations of Taricha granulosa and T. torosa), we detected 18 unique taxa of helminths, fungi, viruses and protozoans. For both newt species, per-host concentrations of TTX, which varied from undetectable to >60 μg/cm² skin, negatively predicted overall parasite richness as well as the likelihood of infection by the chytrid fungus, Batrachochytrium dendrobatidis, and ranavirus. No such effect was found on infection load among infected hosts. Despite commonly occurring at the same wetlands, T. torosa supported higher parasite richness and average infection load than T. granulosa. Host body size and sex (females > males) tended to positively predict infection levels in both species. For hosts in which we quantified leucocyte profiles, total white blood cell count correlated positively with both parasite richness and total infection load. By coupling data on host toxicity and infection by a broad range of micro- and macroparasites, these results suggest that-alongside its effects on predators-tetrodotoxin may help protect newts against parasitic infections, highlighting the importance of integrative research on animal chemistry, immunological defenses and natural enemy ecology.

Biogenic synthesis of copper oxide nanoparticles using olea europaea leaf extract and evaluation of their toxicity activities: An in vivo and in vitro study

Copper oxide nanoparticles (CUNPs) were synthesized using Olea europaea leaf extract as reducing and protecting agent. The formation of nanoparticles was observed through a color change from yellowish to brownish black. The CUNPs were confirmed with UV-Vis spectrophotometer, which revealed a peak absorbance at 289 nm. The synthesized CUNPs were characterized by XRD, FTIR, SEM, and TEM. The XRD pattern revealed that CUNPs were crystalline in nature with a diameter around 20 nm. FTIR spectral analysis showed that CUNPs were capped with plant constituents. From SEM and TEM analyses, the CUNPs were generally found to be spherical in shape, and the size range was 20-50 nm. Free radical scavenging potential of CUNPs against DPPH was confirmed by its stable antioxidant effects. In addition, the toxicity of CUNPs in mice was also assessed by body weight and weights of liver, kidneys, spleen, and thymus. The immune response in mice was signaled through an obvious change in spleen and thymus index, with a decrease of ADA enzyme activity in serum, spleen, and thymus after CUNPs treatment. The CUNPs were found to exert cell growth arrest against AMJ-13 and SKOV-3 cancer cells in a dose-dependent manner and induce cell death by apoptosis. Less significant cytotoxic effect was observed in normal dermal fibroblast cells. These findings suggest that CUNPs may have the potential to be anticancer agents. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:218-230, 2018.

Nickel-smelting fumes increased the expression of HIF-1α through PI3K/ERK pathway in NIH/3T3 cells

OBJECTIVE

The purpose of this study was to investigate the effects of Nickel (Ni) -smelting fumes on oncogenic proteins in vivo and in vitro.

METHODS

Ni fallout beside a Ni smelting furnace in a factory was sampled to study its toxic effect. The effects of Ni-smelting fumes on the regulation of PI3K and ERK signaling pathways and the important downstream hypoxia inducible factor, HIF-1α, were studied both in NIH/3T3 cells and in the lung tissue of rats. NIH/3T3 cell transformation induced by Ni-smelting fumes was also observed.

RESULTS

Ni-smelting fumes activated PI3K, p-AKT, p70S6K1, and ERK proteins and increased HIF-1α expression in a time- and dose-dependent manner. However, activation was suppressed when NIH/3T3 cells were pretreated with PI3K/AKT or ERK inhibitors. Ni-smelting fumes caused malignant transformation of NIH/3T3 cells.

CONCLUSIONS

Ni-smelting fumes increased the expression of HIF-1α through the PI3K/ERK pathway in NIH/3T3 cells and induced malignant transformation in these cells indicating that Ni-smelting fumes may be a potential carcinogen in mammalian cells.