The enteric nervous system and interstitial cells of cajal of the horse

Gastrointestinal diseases, including obstructive and motility disorders such as grass sickness, are very common in the horse. Motility disorders may represent a dysfunction of the neural, muscular or pacemaker components (interstitial cells of Cajal, ICC) of bowel control. ICC are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this ICC-mediated pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Neurons of the enteric nervous system (ENS) are primarily and most severely targeted by the putative neurotoxin causing the disease. The aims of this study were:• to characterise the morphology and neurochemical expression of the equine ENS using tissue culture and immunohistochemistry.• to study the distribution of the ICC in the intestine in normal and grass sicknessaffected horses.• to perform a detailed in vitro investigation of the electrical properties and control of smooth muscle in both the healthy and diseased intestine.• to test the hypothesis that impaired ICC-mediated control is responsible for intestinal dysfunction.Fresh ileal samples were harvested from adult horses free from gastrointestinal disease euthanased on humane grounds. Small mammal (guinea pig and rat) systems were used for comparison and development of techniques. The tissues were microdissected to prepare wholemounts for immunohistochemistry and for either explant or dissociated culture systems of the ENS. Immunoreactivity was assessed using a standard indirect immunofluorescence technique. In the horse, explant culture systems were established using wholemounts of either the submucous plexus or the muscularis externa (including the myenteric plexus). Dissociated cell cultures could only be obtained from the submucous plexus. This was in contrast to small mammal models where enteric neurons were grown in both the myenteric and submucous systems. Culture systems were maintained for up to 5 days in the horse and 8 days in the guinea pig. Immunoreactivity for a neuronal marker {Pan-N) and for glial cell markers (GFAP and SI00) indicated the presence of both neurons and enteric glia in the tissue culture preparations. Further refinements to the techniques will be required before this in vitro model can be used for quantitative analysis.To examine the ICC in the horse, samples were taken at multiple anatomicallydefined sites from stomach to small colon. After tissue fixation in 10% phosphatebuffered formalin, 10 pm cryostat sections were processed using standard immunohistochemical techniques and the avidin-biotin-peroxidase method. The primary antiserum used was an affinity-purified polyclonal antibody raised against the c-Kit protein. Specific immunoreactivity for c-Kit was detected in all sites and three types of immunoreactive cell were identified. These were spindle-shaped cells in the region of the myenteric plexus with occasional cellular processes extending into the longitudinal muscle, stellate- or bipolar-shaped cells in the circular muscle layer and round cells in the submucosa. The round cells were shown to be mast cells with the use of toluidine blue staining whereas the other c-Kit-immunoreactive cells did not exhibit metachromasia and were therefore classified as ICC. In the duodenum, jejunum and ileum, ICC were found predominantly in the region of the myenteric plexus and to a lesser extent in the circular muscle. In contrast, in the large intestine (large colon, caecum, small colon) most cells were seen throughout the circular muscle and very few ICC were seen in the myenteric plexus area. A semi¬ quantitative grading system was used to examine any differences in ICC in grass sickness-affected ileum and pelvic flexure sections compared to normal animals. In horses with grass sickness, ICC were significantly decreased in both the myenteric plexus and circular muscle regions of both ileum and pelvic flexure compared to normal animals. It is possible therefore that the decline in ICC may be in some way responsible for the development of intestinal dysmotility in grass sickness.Normal and diseased equine tissue from clinical cases and abattoir samples from pigs were collected and examined using in vitro microelectrode electrophysiological recordings from smooth muscle cells. Slow wave activity and spike potentials were recorded in normal equine and porcine ileal preparations. The slow wave activity was preserved in the presence of tetrodotoxin. A waxing and waning pattern of the slow wave activity was noted. Nifedipine abolished the spiking contractile activity of the smooth muscle but did not abolish the slow waves. The majority of ileal preparations from grass sickness-affected horses exhibited prominent slow wave activity with reduced slow wave frequency and increased duration suggesting that, although the neural elements are destroyed, the ICC-mediated pacemaker function remains intact.This work will increase understanding of gastrointestinal dysmotility and information on the role of ICC will also offer benefits in potential developments in pharmacological therapy

Flow cytometric phenotyping of diverse human cancer cell lines for immunological biomarkers expression

The tumour microenvironment contains a variety of distinct factors that inhibit the immune system and can cause drug resistance. Some of these factors include the expression of cell surface markers which interact directly with immune cells. Cancer cells express programmed death ligand 1 (PD-L1) and reduce the expression of major-histocompatibility complex class I, death-receptors 4/5 and Fas, limiting immune-mediated cancer cell killing. Targeting these immune markers alone or in combination could potentially increase cancer cell death and improve drug efficacy. Utilising flow cytometric analysis on breast, prostate and colorectal cancer cell lines, we have found differential expression of these markers depending on the cancer type. These findings provide a platform for future work that will entail siRNA knockdown of PD-L1 to determine the tumour-intrinsic role of this ligand, in addition to combination therapies in 2D and 3D cell culture

The Extrinsic and Intrinsic Roles of PD-L1 and Its Receptor PD-1: Implications for Immunotherapy Treatment

Programmed death-ligand 1 (PD-L1) is an immune checkpoint inhibitor that binds to its receptor PD-1 expressed by T cells and other immune cells to regulate immune responses; ultimately preventing exacerbated activation and autoimmunity. Many tumors exploit this mechanism by overexpressing PD-L1 which often correlates with poor prognosis. Some tumors have also recently been shown to express PD-1. On tumors, PD-L1 binding to PD-1 on immune cells promotes immune evasion and tumor progression, primarily by inhibition of cytotoxic T lymphocyte effector function. PD-1/PD-L1-targeted therapy has revolutionized the cancer therapy landscape and has become the first-line treatment for some cancers, due to their ability to promote durable anti-tumor immune responses in select patients with advanced cancers. Despite this clinical success, some patients have shown to be unresponsive, hyperprogressive or develop resistance to PD-1/PD-L1-targeted therapy. The exact mechanisms for this are still unclear. This review will discuss the current status of PD-1/PD-L1-targeted therapy, oncogenic expression of PD-L1, the new and emerging tumor-intrinisic roles of PD-L1 and its receptor PD-1 and how they may contribute to tumor progression and immunotherapy responses as shown in different oncology models

The Welfare of Traveller and Gypsy Owned Horses in the UK and Ireland

SIMPLE SUMMARY: Travellers and Gypsies are recognised ethnic groups in the UK and Ireland. Horse ownership is an important part of their lives; however, poor horse welfare is often perceived to be associated with these horse-owning communities. Nevertheless, studies on the welfare of Traveller and Gypsy-owned horses are lacking. The welfare of 104 horses in the UK and Ireland was evaluated using a horse welfare protocol that assessed health conditions, resource provision, management and horse behaviour. In order to potentially understand how a horse was feeling, Qualitative Behaviour Assessment (QBA) was used to evaluate their body language. Most horses were found to have good body condition, a healthy coat and few skin problems or joint issues, however, 27% of horses were found to have neglected hooves. In the voluntary animal approach test, most horses showed a friendly response. Positive QBA terms were more prevalent than negative terms, therefore, the emotional state of Traveller and Gypsy owned horses was deemed to be positive overall. An association between QBA and various horse welfare measures was identified, e.g., improved mood was associated with better water availability. Findings in this study did not support previous negative perceptions of horse welfare in Traveller and Gypsy horse owning communities. ABSTRACT: Travellers and Gypsies are recognised ethnic groups in the UK and Ireland. Horse ownership is an important cultural tradition, however, practices associated with poor welfare are often perceived to be linked to these horse owning communities. Despite this, empirical studies on the welfare status of Traveller and Gypsy owned horses are lacking. To determine the welfare status of Traveller and Gypsy owned horses, 104 horses were assessed using a bespoke horse welfare protocol. This protocol assessed animal, resource and management-based measures. In addition, Qualitative Behaviour Assessment (QBA) identified horses’ emotional state. Results indicated that 81% of horses had an optimal body condition score, with no horse recorded as very thin/fat. The absence of limb conditions (95%), ocular (98%) and nasal (93%) discharges were evident in most horses, and 81% of horses responded positively to the voluntary animal approach test. The most commonly observed welfare issues were hoof neglect (27%), with hoof cracks/breakages (19%) being the most prevalent. QBA indicated that positive emotional states were more commonplace than negative. A relationship between QBA and other horse welfare measures was observed, e.g., improved mood was associated with better water availability. This research provides novel data in the under-researched area of the welfare of Traveller and Gypsy owned horses and counters perceptions of a poor welfare state in this group of horses

The contested jurisdiction of Social Policy in UK universities since 1972

Utilising Abbott’s work on professions and disciplines we trace the broad development of Social Policy in UK universities over the past 50 years. As with all subjects, Social Policy is enmeshed in continuous boundary protection, and at the same time may seek to extend jurisdiction by laying claim to areas and activities undertaken by others. We draw on a range of sources to inform our analysis including: overviews of contributions to Journal of Social Policy; reviews of selected available UK Social Policy Association documents such as newsletters; reviews of research quality (Research Assessment Exercise/Research Excellence Framework) submissions; and student numbers data. In conclusion we consider whether reassessment of some of the jurisdictional battles of the past 50 years might provide routes forward for the subject to flourish in the current environment

Immunohistochemical study of morphology and distribution of CD163+ve macrophages in the normal adult equine gastrointestinal tract

Intestinal macrophages are the largest group of mononuclear phagocytes in the body and play a role in intestinal innate immunity, neuroimmune interactions and maintaining intestinal homeostasis. Conversely, they also are implicated in numerous pathologies of the gastrointestinal tract, such as postoperative ileus and inflammatory bowel disease. As a result, macrophages could be potential therapeutic targets. To date, there are limited studies on the morphology and distribution of macrophages in the equine gastrointestinal tract (GIT). The aim of this study was to identify the location and abundance of resident macrophages in the equine GIT using CD163 as an immunohistochemical marker. Tissue samples were obtained post-mortem from 14 sites along the gastrointestinal tracts of 10 horses free from gastrointestinal disease; sample sites extended from the stomach to the small colon. CD163 cells were present in all regions of the equine GIT from stomach to small colon. CD163 cells were also identified in all tissue layers of the intestinal wall, namely, mucosa, submucosa, muscularis externa (ME), myenteric plexus and serosa. Consistent with a proposed function in regulation of intestinal motility, CD163 cells were regularly distributed within the ME, with accumulations closely associated with the myenteric plexus and effector cells such as neurons and the interstitial cells of Cajal (ICC)