The role of neutrophil extracellular traps in the pathogenesis of periodontal diseases

This thesis investigated neutrophil extracellular traps (NETs) in the pathogenesis of periodontal diseases, including chronic periodontitis, experimental gingivitis and Papillon Lefèvre syndrome (PLS). $In$ $vitro$ assays investigated the interactions between periodontal bacteria and peripheral neutrophils isolated by discontinuous Percoll gradients, and demonstrated differential NET release in response to bacteria. Interestingly, NETs entrapped all periodontal bacteria assayed to some extent; however bacterial growth and survival were not impeded. A longitudinal intervention clinical study of chronic periodontitis patients and matched healthy controls revealed no differences in peripheral NET production; however NET production by patients decreased following non-surgical treatment. Furthermore, a subset of patients displayed impeded NET degradation by plasma that was restored following disease treatment; this may be the result of increased circulating immunoglobulins and free light chains (FLCs) pre-treatment. Peripheral NET production did not change throughout the experimental gingivitis model study; however NET release was impeded in PLS patients relative to healthy controls. Additional $in$ $vitro$ studies demonstrated that cigarette smoking had an inhibitory effect on NET release. Collectively, this thesis indicates that NETs contribute to innate immunity, however, given that periodontitis pathogenesis is characterised by aberrant neutrophil responses, NETs may also be involved in the progression of the disease

Comparison of 25‐hydroxyvitamin D concentration in chimpanzee dried blood spots and serum

BackgroundDried blood spots (DBS) are used in human medicine to measure total 25‐hydroxyvitamin D (25‐OHD) in the blood. However, this easy and affordable sampling technique has not been evaluated in primates to measure vitamin D concentrations.ObjectivesWe aimed to compare 25‐OHD measurements in chimpanzee serum at two different laboratories and determine the precision and accuracy of the DBS method by comparing DBS and serum results.MethodsBlood samples from 17 captive chimpanzees were collected, and 25‐OHD3 and 25‐OHD2 were measured in serum at two accredited laboratories using liquid chromatography‐tandem mass spectrometry. The same analytes were measured on DBS cards, and results were compared with that of serum. Data were assessed using the Spearman correlation, Deming regression, and Bland‐Altman analyses. ResultsThe correlation coefficient between the two measurements in serum was r s = .51 (P = .04), and the mean bias was −1.25 ± 14.83. When comparing 25‐OHD concentrations measured in DBS and serum at the same laboratory, the r s was 0.7 (P = .002), and the mean bias was 1.42 ± 14.58. Estimated intra‐assay and inter‐assay coefficients of variation for DBS results were 6% and 12.6%, respectively. ConclusionsAlthough substantial analytical variability was found in 25‐OHD measurements regardless of the sample type, the identification of both constant and proportional error and wider limits of agreement with the DBS technique makes the interpretation of DBS results challenging, especially for values close to clinical cut‐off points. The DBS and serum methods were not interchangeable, and further studies are needed to validate DBS samples for vitamin D measurements in chimpanzees

Modulation of neutrophil extracellular trap and reactive oxygen species release by periodontal bacteria

ABSTRACT Oral bacteria are the main trigger for the development of periodontitis, and some species are known to modulate neutrophil function. This study aimed to explore the release of neutrophil extracellular traps (NETs), associated antimicrobial proteins, and reactive oxygen species (ROS) in response to periodontal bacteria, as well as the underlying pathways. Isolated peripheral blood neutrophils were stimulated with 19 periodontal bacteria. NET and ROS release, as well as the expression of NET-bound antimicrobial proteins, elastase, myeloperoxidase, and cathepsin G, in response to these species was measured using fluorescence-based assays. NET and ROS release was monitored after the addition of NADP (NADPH) oxidase pathway modulators and inhibitors of Toll-like receptors (TLRs). Moreover, bacterial entrapment by NETs was visualized microscopically, and bacterial killing was assessed by bacterial culture. Certain microorganisms, e.g., Veillonella parvula and Streptococcus gordonii , stimulated higher levels of ROS and NET release than others. NETs were found to entrap, but not kill, all periodontal bacteria tested. NADPH oxidase pathway modulators decreased ROS production but not NET production in response to the bacteria. Interestingly, TLR inhibitors did not impact ROS and NET release. These data suggest that the variability in the neutrophil response toward different bacteria may contribute to the pathogenesis of periodontal diseases by mechanisms such as bacterial avoidance of host responses and activation of neutrophils. Moreover, our results indicate that bacterium-stimulated NET release may arise in part via NADPH oxidase-independent mechanisms. The role of TLR signaling in bacterium-induced ROS and NET release needs to be further elucidated. </jats:p

Assessing the Educational Value of a Zoo Placement for Veterinary Students: A Report on Student Feedback and Perceptions

Zoological medicine is an expanding field with limited practical training opportunities for veterinary students. Those training programs that do exist require significant financial and resource investment by both veterinary schools and the zoological organizations involved. This article summarizes the findings of a retrospective survey of students carried out to ascertain the educational value of a compulsory 5-day-long zoo clinical placement for final-year veterinary students. We aimed to explore the placement’s potential impact on students’ knowledge and attitudes toward zoological medicine and the role of modern zoos and conservation. Data were collected by means of an end-of-placement questionnaire (N = 200) and statistically analyzed for pre- versus post-placement changes and the effect of pre-placement interest and experience on student responses. Despite the placement’s short time frame and lack of opportunity for in-depth comprehensive training in zoological medicine, students reported that the placement had a positive educational impact. More than 90% of students stated that their understanding about modern zoos was good or excellent at the end of the placement (compared with 35.0% before the placement), and 43.0% reported that the placement had a positive impact on their attitudes toward zoos. Students self-reported an increased understanding of the work of zoo clinicians, and there was a highly significant positive change in the students’ reported opinions regarding wildlife conservation in general. We provide preliminary evidence to suggest that even short-duration but immersive zoo-based practical training has positive educational value for veterinary students

Drivers of jaguar (Panthera onca) and puma (Puma concolor) predation on endangered primates within a transformed landscape in southern Mexico

Human pressures have increasingly placed keystone species, such as large cats, under threat. Together with forest loss, prey depletion is one of the main threats to the survival of jaguars (Panthera onca) and pumas (Puma concolor) throughout the Neotropics. Generally, primates are not considered main prey for jaguar and puma, and their inclusion in the diet could be indicative of ongoing prey species decline. Here, we investigate the effect of habitat type and disturbance on primate predation by large cats. Surveys took place during the dry seasons (March to June) of 2010 and 2011, covering a total of 608.5 km across 24 localities in the Uxpanapa Valley, Mexico. We found 65 felid scat samples with the aid of a wildlife scat detection dog, and then examined them to identify predator species and classify the prey remains they contained. Primates represented the most frequent prey (35%) for both jaguar and puma in our study site and constituted approximately half of the biomass consumed by these felines in the area. Primate remains were more likely to be found in scats surrounded by the lowest percentage of conserved forest or in areas surrounded by more villages, showing the potential effects of human activities on these species' populations. The high proportion of primates found in scats within our study site could be an early indication that populations of ungulates and other “typical” prey are beginning to collapse, and urgent conservation interventions are needed for both large cats and primates before they become locally extinct

Vitamin D status in chimpanzees in human care: a Europe wide study

While vitamin D deficiency is a public health concern in humans, comparatively little is known about vitamin D levels in non-human primates. Vitamin D plays a crucial role in overall health and its deficiency is associated with a range of disorders, including cardiovascular disease, which is a leading cause of death in great apes. 25 Serum samples (n=245) from chimpanzees (Pan troglodytes) housed at 32 European zoos were measured for 25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and total 25-hydroxyvitamin D (25-OHD) using liquid chromatography and tandem mass spectrometry. Of these samples, 33.1% indicated inadequate vitamin D status, using the human reference interval (25-OHD<50 nmol/L). The season of the year, health status of the animal, and the provision of daily outdoor access had a significant effect on vitamin D status. This is the first 30 large-scale study on vitamin D status of non-human great apes in human care. Inadequate 25-OHD serum concentrations are widespread in the chimpanzee population in Europe and could be a risk factor for the development of idiopathic myocardial fibrosis, a major cause of mortality in this species, as well as other diseases. A review of husbandry and nutrition practices is recommended to ensure optimal vitamin D supply for these endangered animals. 3