Assessing the Risks to Bats from Plant Protection Products: A Review of the Recent European Food Safety Authority Statement Regarding Toxicity and Exposure Routes

Wild birds and mammals that feed in agricultural habitats are potentially exposed to pesticides through various routes. Until recently, it has been implicitly assumed that the existing European Union risk assessment scheme for birds and mammals also covered bats (Chiroptera). However, recent publications raised concerns and, in 2019, a scientific statement was published by the European Food Safety Authority (EFSA) that concluded that bats were not adequately covered by the current risk assessment scheme. We review the evidence presented and assumptions made in the EFSA bat statement relating to toxicity, bioaccumulation, and exposure pathways (oral, dermal, and inhalation), in terms of their relevance for bats potentially foraging in agricultural areas in the European Union; we highlight where uncertainties remain and how these could be addressed. Based on our review, it is clear that there is still much uncertainty with regard to the appropriateness of the assumptions made in the EFSA bat statement. Significantly more information needs to be gathered to answer fundamental questions regarding bat behavior in agricultural landscapes, together with the relative sensitivity of bats to pesticide exposure. Given the current critical information gaps, it is recommended that quantitative risk assessments for bats not be performed for pesticides until more robust, reliable, and relevant data are available. The risk to bats can then be compared with that for birds and ground-dwelling mammals, to determine the protectiveness of the existing scheme and thus whether a bat scenario is indeed required and under what circumstances. Environ Toxicol Chem 2021;40:2978-2989. © 2021 Cambridge Environmental Assessments, part of RSK ADAS Ltd. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Glycolipid-Containing Nanoparticle Vaccine Engages Invariant NKT Cells to Enhance Humoral Protection against Systemic Bacterial Infection but Abrogates T-Independent Vaccine Responses

CD4⁺ T cells enable the critical B cell humoral immune protection afforded by most effective vaccines. We and others have recently identified an alternative source of help for B cells in mice, invariant NK T (iNKT) cells. iNKT cells are innate glycolipid-specific T cells restricted to the nonpolymorphic Ag-presenting molecule CD1d. As such, iNKT cells respond to glycolipids equally well in all people, making them an appealing adjuvant for universal vaccines. We tested the potential for the iNKT glycolipid agonist, α-galactosylceramide (αGC), to serve as an adjuvant for a known human protective epitope by creating a nanoparticle that delivers αGC plus antigenic polysaccharides from Streptococcus pneumoniae αGC-embedded nanoparticles activate murine iNKT cells and B cells in vitro and in vivo, facilitate significant dose sparing, and avoid iNKT anergy. Nanoparticles containing αGC plus S. pneumoniae polysaccharides elicits robust IgM and IgG in vivo and protect mice against lethal systemic S. pneumoniae However, codelivery of αGC via nanoparticles actually eliminated Ab protection elicited by a T-independent S. pneumoniae vaccine. This is consistent with previous studies demonstrating iNKT cell help for B cells following acute activation, but negative regulation of B cells during chronic inflammation. αGC-containing nanoparticles represent a viable platform for broadly efficacious vaccines against deadly human pathogens, but their potential for eliminating B cells under certain conditions suggests further clarity on iNKT cell interactions with B cells is warranted.

New Functional Tools for Antithrombogenic Activity Assessment of Live Surface Glycocalyx

OBJECTIVE

It is widely accepted that the presence of a glycosaminoglycan-rich glycocalyx is essential for endothelialized vasculature health; in fact, a damaged or impaired glycocalyx has been demonstrated in many vascular diseases. Currently, there are no methods that characterize glycocalyx functionality, thus limiting investigators' ability to assess the role of the glycocalyx in vascular health.

APPROACH AND RESULTS

We have developed novel, easy-to-use, in vitro assays that directly quantify live endothelialized surface's functional heparin weights and their anticoagulant capacity to inactivate Factor Xa and thrombin. Using our assays, we characterized 2 commonly used vascular models: native rat aorta and cultured human umbilical vein endothelial cell monolayer. We determined heparin contents to be ≈10 000 ng/cm(2) on the native aorta and ≈10-fold lower on cultured human umbilical vein endothelial cells. Interestingly, human umbilical vein endothelial cells demonstrated a 5-fold lower anticoagulation capacity in inactivating both Factor Xa and thrombin relative to native aortas. We verified the validity and accuracy of the novel assays developed in this work using liquid chromatography-mass spectrometry analysis.

CONCLUSIONS

Our assays are of high relevance in the vascular community because they can be used to establish the antithrombogenic capacity of many different types of surfaces such as vascular grafts and transplants. This work will also advance the capacity for glycocalyx-targeting therapeutics development to treat damaged vasculatures.

Abstract 5499: Necuparanib affects tumor progression and invasion in a 3D co-culture system of pancreatic cancer cells and stellate cells

Pancreatic cancer is one of the most aggressive and deadliest cancers, with only about 5% of patients surviving 5 years past the initial diagnosis. In over 80% of patients the cancer has already spread to distant organs at the time of diagnosis, making it difficult to treat. Most alarmingly, pancreatic cancer is the only cancer for which deaths are predicted to increase over the next few years. Despite advances with new chemotherapy combinations, overall survival outcomes are still dismal and require novel therapeutic approaches. Necuparanib (formerly M402) is a heparan sulfate-like molecule that binds and inhibits multiple heparin-binding growth factors, chemokines, adhesion molecules and enzymes involved in cancer progression and metastasis and as such modulates multiple elements of the tumor microenvironment. In order to further explore the mechanism of action for epithelial-stromal interactions affected by necuparanib, a 3-dimensional culture system mimicking pancreatic cancer was developed containing a co-culture of pancreatic tumor cells and pancreatic stellate cells, the most abundant stromal cell in the pancreas. In this culture system, pancreatic cancer cells form a tumor spheroid embedded in a matrix that is a mixture of type I collagen and basement membrane extract and contains pancreatic stellate cells. Notably, pancreatic cancer cells required the co-culture with pancreatic stellate cells to become invasive in vitro. Conditioned medium derived from pancreatic stellate cells could not mimic this effect indicating that soluble factors are not sufficient to cause invasion into surrounding matrix. Necuparanib inhibited the invasive behavior in a dose-dependent manner. The effect of pancreatic stellate cells on tumor cell invasion and the effect of necuparanib on stromal cells were further explored in this culture system. We showed an effect of necuparanib on proliferation, migration and invasion of pancreatic tumor cells. These studies aid in our understanding of the key biological targets and pathways responsible for necuparanib's anti-tumor effects and support biomarker discovery in the ongoing Phase 2 efficacy study in metastatic pancreatic cancer.

Citation Format: Silva Krause, Amanda Weyers, Katie Loveluck, Birgit Schultes. Necuparanib affects tumor progression and invasion in a 3D co-culture system of pancreatic cancer cells and stellate cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5499. doi:10.1158/1538-7445.AM2015-5499

Click-coated, heparinized, decellularized vascular grafts

A novel method enabling the engineering of a dense and appropriately oriented heparin-containing layer on decellularized aortas has been developed. Amino groups of decellularized aortas were first modified to azido groups using 3-azidobenzoic acid. Azide-clickable dendrons were attached onto the azido groups through "alkyne-azide" click chemistry, affording a tenfold amplification of adhesions sites. Dendron end groups were finally decorated with end-on modified heparin chains. Heparin chains were oriented like heparan sulfate groups on native endothelial cells surface. X-ray photoelectron spectroscopy, nuclear magnetic resonance imaging, mass spectrometry and Fourier transform infrared FTIR spectroscopy were used to characterize the synthesis steps, building the final heparin layered coatings. The continuity of the heparin coating was verified using fluorescent microscopy and histological analysis. The efficacy of heparin linkage was demonstrated with factor Xa anti-thrombogenic assay and platelet adhesion studies. The results suggest that oriented heparin immobilization to decellularized aortas may improve the in vivo blood compatibility of decellularized aortas and vessels.

Carbohydrate-containing molecules as potential biomarkers in colon cancer

Glycans play a critical role in physiological and pathological processes through interaction with a variety of ligands. Altered expression and dysregulation of these molecules can cause aberrant cellular function such as malignancy. Glycomics provide information of the structure and function of glycans, glycolipids, and glycoproteins such as proteoglycans, and may help to predict cancer development and progression as biomarkers. In this report, we compared the expression of proteoglycans, the content and structure of glycosaminoglycans and glycolipids between patient-matched normal and cancer tissues obtained from colon cancer patients. Tumor-related proteoglycans, glypican-3, and syndecan-1 showed downregulation in cancer tissues compared to normal tissues. In cancer tissue, the total amount of chondroitin sulfate (CS)/dermatan sulfate and heparan sulfate were lower and, interestingly, the level of disaccharide units of both 4S6S (CS-E) and 6S (CS-C) were higher compared to normal tissue. Also, overall lipids including glycolipids, a major glycomics target, were analyzed by hydrophilic interaction liquid chromatography mass spectrometry. Increase of lyso-phosphatidylcholine (phospholipid), sphingomyelin (sphigolipid), and four types of glycolipids (glucosylceramide, lactosylceramide, monosialic acid ganglioside, and globoside 4) in cancer tissue showed the possibility as potential biomarkers in colon cancer. While requiring the need for careful interpretation, this type of broad investigation gives us a better understanding of pathophysiological roles on glycosaminoglycans and glycolipids and might be a powerful tool for colon cancer diagnosis.

Microanalysis of stomach cancer glycosaminoglycans

Glycosaminoglycans (GAGS) are anionic, linear, polysaccharides involved in cell signaling. The GAG content, composition and structure of human tissue have been suggested to play a role in cancer and might provide useful diagnostic or prognostic markers. The current study examines 17 stomach tissue biopsy samples taken from normal individuals and from patients with gastric cancers. An ultrasensitive liquid chromatography (LC) - mass spectrometry assay was applied to individual biopsy samples as small 250 μg providing GAG content and disaccharide composition. The results of these analyses show a significant increase in non-sulfated chondroitin/dermatan sulfate concentration in all cancer samples when compared to normal tissues. In addition in advanced gastric cancer, a significant decrease is observed in hyaluronan.

Neoproteoglycans in tissue engineering

Proteoglycans, comprised of a core protein to which glycosaminoglycan chains are covalently linked, are an important structural and functional family of macromolecules found in the extracellular matrix. Advances in our understanding of biological interactions have lead to a greater appreciation for the need to design tissue engineering scaffolds that incorporate mimetics of key extracellular matrix components. A variety of synthetic and semisynthetic molecules and polymers have been examined by tissue engineers that serve as structural, chemical and biological replacements for proteoglycans. These proteoglycan mimetics have been referred to as neoproteoglycans and serve as functional and therapeutic replacements for natural proteoglycans that are often unavailable for tissue engineering studies. Although neoproteoglycans have important limitations, such as limited signaling ability and biocompatibility, they have shown promise in replacing the natural activity of proteoglycans through cell and protein binding interactions. This review focuses on the recent in vivo and in vitro tissue engineering applications of three basic types of neoproteoglycan structures, protein-glycosaminoglycan conjugates, nano-glycosaminoglycan composites and polymer-glycosaminoglycan complexes.

Isolation of bovine corneal keratan sulfate and its growth factor and morphogen binding

Keratan sulfate (KS) is an important glycosaminoglycan that is found in cartilage, reproductive tissues, and neural tissues. Corneal KS glycosaminoglycan is found N-linked to lumican, keratocan and mimecan proteoglycans, and has been widely studied by investigators interested in corneal development and diseases. Recently, the availability of corneal KS has become severely limited, owing to restrictions on the shipment of bovine central nervous system byproducts across international borders in an effort to prevent additional cases of mad cow disease. We report a simple method for the purification of multi-milligram quantities of bovine corneal KS, and characterize its structural properties. We also examined its protein-binding properties, and discovered that corneal KS bound with high affinity to fibroblast growth factor-2 and sonic hedgehog, a growth factor and a morphogen involved in corneal development and healing.

A structural analysis of glycosaminoglycans from lethal and nonlethal breast cancer tissues: toward a novel class of theragnostics for personalized medicine in oncology?

Cancer is one of the leading noncommunicable diseases that vastly impacts both developed and developing countries. Truly innovative diagnostics that inform disease susceptibility, prognosis, and/or response to treatment (theragnostics) are seriously needed for global public health and personalized medicine for patients with cancer. This study examined the structure and content of glycosaminoglycans (GAGs) in lethal and nonlethal breast cancer tissues from six patients. The glycosaminoglycan content isolated from tissue containing lethal cancer tumors was approximately twice that of other tissues. Molecular weight analysis showed that glycosaminoglycans from cancerous tissue had a longer weight average chain length by an average of five disaccharide units, an increase of approximately 15%. Dissacharide analysis found differences in sulfation patterns between cancerous and normal tissues, as well as sulfation differences in GAG chains isolated from patients with lethal and nonlethal cancer. Specifically, cancerous tissue showed an increase in sulfation at the "6S" position of CS chains and an increase in the levels of the HS disaccharide NSCS. Patients with lethal cancer showed a decrease in HS sulfation, with lower levels of "6S" and higher levels of the unsulfated "0S" disaccharide. Although these findings come from a limited sample size, they indicate that structural changes in GAGs exist between cancerous and noncancerous tissues and between tissues from patients with highly metastatic cancer and cancer that was successfully treated by chemotherapy. Based on these findings, we hypothesize that (1) there are putative changes in the body's construction of GAGs as tissue becomes cancerous; (2) there may be innate structural person-to-person variations in GAG composition that facilitate the metastasis of tumors in some patients when they develop cancer.

Ultra-performance ion-pairing liquid chromatography with on-line electrospray ion trap mass spectrometry for heparin disaccharide analysis

A high-resolution method for the separation and analysis of disaccharides prepared from heparin and heparan sulfate (HS) using heparin lyases is described. Ultra-performance liquid chromatography in a reverse-phase ion-pairing mode efficiently separates eight heparin/HS disaccharides. The disaccharides can then be detected and quantified using electrospray ionization mass spectrometry. This method is particularly useful in the analysis of small amounts of biological samples, including cells, tissues, and biological fluids, because it provides high sensitivity without being subject to interference from proteins, peptides, and other sample impurities.

Impact of autoclave sterilization on the activity and structure of formulated heparin

The stability of a formulated heparin was examined during its sterilization by autoclaving. A new method to follow loss in heparin binding to the serine protease inhibitor, antithrombin III, and the serine protease, thrombin, was developed using a surface plasmon resonance competitive binding assay. This loss in binding affinity correlated well with loss in antifactor IIa (thrombin) activity as well as antifactor Xa activity as measured using conventional amidolytic assays. Autoclaving also resulted in a modest breakdown of the heparin backbone as confirmed by a slight reduction in number-averaged and weight-averaged molecular weight and an increase in polydispersity. Although no clear changes were observed by nuclear magnetic resonance spectroscopy, disaccharide composition analysis using high-performance liquid chromatography-electrospray ionization-mass spectrometry suggested that loss of selected sulfo groups had taken place. It is this sulfo group loss that probably accounts for a decrease in the binding of autoclaved heparin to antithrombin III and thrombin as well as the observed decrease in its amidolytic activity.

Genotoxicity of AMPA, the environmental metabolite of glyphosate, assessed by the Comet assay and cytogenetic tests

Formulations containing glyphosate are the most widely used herbicides in the world. AMPA is the major environmental breakdown product of glyphosate. The purpose of this study is to evaluate the in vitro genotoxicity of AMPA using the Comet assay in Hep-2 cells after 4h of incubation and the chromosome aberration (CA) test in human lymphocytes after 48h of exposition. Potential in vivo genotoxicity was evaluated through the micronucleus test in mice. In the Comet assay, the level of DNA damage in exposed cells at 2.5-7.5mM showed a significant increase compared with the control group. In human lymphocytes we found statistically significant clastogenic effect AMPA at 1.8mM compared with the control group. In vivo, the micronucleus test rendered significant statistical increases at 200-400mg/kg. AMPA was genotoxic in the three performed tests. Very scarce data are available about AMPA potential genotoxicity.

Increase of tissue lipid hydroperoxides as determination of oxidative stress

Increased levels of lipid hydroperoxides (LOOH) are frequently associated with the oxidative mechanisms involved in physiological states as ageing and with serious pathological conditions. In the present work the physiological and the CCl4-induced lipid hydroperoxides levels in mice liver and kidney were determined. The analysis of LOOH tissue levels was performed through the oxidation of 1-napthyldiphenylphosphine (NDPP) into its oxide (ONDPP) and further quantification by high pressure liquid chromatography at 292 nm UV detection. The physiological level of lipid hydroperoxides levels was higher in the kidney (245 +/- 8 nmol LOOH/g of tissue) than in liver (164 +/- 5 nmol of LOOH/g tissue). After a single administration of CCl4 (0.25 ml/g) tissue LOOH reached a maximum level after 15 min (416 +/- 21 nmol/g kidney and 303 +/- 6 nmol/g liver) and then slowly decreased. LOOH levels in liver afforded an early indicator (15 min) of oxidative damage. LOOH levels in kidney remained significatively increased up to 60 min post administration. The described HPLC assay is a useful, simple and sensitive method to detect cellular oxidative stress and damage.

Algal growth inhibition: effect of the choice of growth rate or biomass as endpoint on the classification and labelling of new substances notified in the EU

From the complete base set notifications of new substances currently available, we have investigated what effects the choice of using growth rate or biomass in the algal growth inhibition test has on the relative sensitivity of the three aquatic toxicity tests. Both parameters derived from the algal test were more sensitive than either fish or Daphnia tests. Changes in the classification of substances after the removal of either algae, Daphnia or fish data from the base set, when applying current legal practice, occur in 22.9%, 6.6% and 4.8% of the notifications, respectively. When always using growth rate as a parameter, these numbers change to 15.4%, 9.2% and 7.2%, respectively.

Human companion-animal relationships in the veterinary consulting room

A questionnaire, based on 14 years' private practice experience and psychological principles, was compiled to establish the reasons why veterinary clients are involved with their pets. Questionnaires were sent to South African veterinarians country-wide and only clients visiting veterinarians were requested to complete the questionnaires anonymously. Questionnaires (n = 612) were returned and the data was processed by computer. The results indicated that clients are involved with their companion animals for emotional, social and relaxational reasons, which all have psychological implications. They are, however, also involved with their animals by caring for them, and they keep them for utility or economical reasons and also due to their general interest in nature. The latter reasons could be seen as natural reasons for keeping pets. The same relationship between clients and their pets continue during veterinary consultations. Because of this continuing involvement, some clients may consult veterinarians mainly for psychological reasons and others mainly for clinical reasons. There is a constant interaction between these motivations for veterinary consultations. Client consultations of veterinarians could thus be categorised into psychological consultations which are predominantly human/client orientated and clinical consultations which are predominantly animal/patient orientated.

[Client profile of an animal companion practice]

The aim of the study was to gather demographic information from consulting clients, to compile a profile of the typical companion animal client in South Africa. This method differed from other studies in that information was collected from actual clients and not from pet owners. Completed questionnaires (n = 612) were received back from veterinary practices (n = 120) in South Africa. The data was processed by a computer. Questionnaires were completed on a voluntary basis and were anonymous. The typical client in this survey was a young married woman, with one or two children, living in a suburban home, with an average income and 2 companion animals. The most common companion animal presented, proved to be a miniature breed of dog. The advantage of this study is that veterinarians may use it to prepare themselves in terms of the most common type of client as well as of a variety of other types. The client profile also gives an indication of the level at which consultations should be conducted, and may aid the veterinarian in developing a specific sensitivity towards certain clients.