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dc.contributor.advisorMellanby, Richard
dc.contributor.authorTitmarsh, Helen Faye
dc.date.accessioned2017-04-04T09:51:57Z
dc.date.available2017-04-04T09:51:57Z
dc.date.issued2015-11-27
dc.identifier.urihttp://hdl.handle.net/1842/21060
dc.description.abstractVitamin D is traditionally known for its role in calcium homeostasis and bone metabolism. However, it has been demonstrated that numerous types of cells express the vitamin D receptor and it is now clear that the physiological roles of vitamin D extend beyond the maintenance of skeletal health. Vitamin D insufficiency, which is typically assessed by measuring the major circulating form of vitamin D, 25 hydroxyvitamin D (25(OH)D), has been associated with a number of disorders in people including hypertension, diabetes, cardiovascular diseases, cancer, autoimmune conditions and infectious diseases. Meta-analyses have demonstrated that serum 25(OH)D concentrations are an important predictor of survival in people with a wide variety of illnesses and have been linked to all-cause mortality in the general human population. The role of vitamin D in non-skeletal disorders in cats and dogs is poorly understood. This is surprising since cats and dogs could act as excellent models for probing the biology of vitamin D. Vitamin D status in people is largely dependent on cutaneous production of vitamin D. This is influenced by many factors such as season, latitude and exposure to ultraviolet (UV) radiation. The interpretation of human studies investigating the effects vitamin D status on disease outcomes are therefore influenced by a number of confounding variables. Unlike humans, domesticated cats and dogs do not produce vitamin D cutaneously and obtain vitamin D only from their diet. The physiological functions and regulation of vitamin D are otherwise similar to humans. Most pets are fed commercial diets containing a relatively standard amount of vitamin D. Consequently, companion animals are attractive model systems in which to examine the relationship vitamin D status and health outcomes. Furthermore, spontaneously occurring model systems which did not require disease to be induced in healthy animals would allow the numbers of animals used in scientist research to be reduced. This thesis aimed to define vitamin D homeostasis in companion animals in three disease settings; in cats with feline immunodeficiency virus (FIV) infection, dogs with chronic enteropathies (CE) and in hospitalised ill cats. Additional aims were to assess the prognostic significance of serum 25(OH)D concentrations in companion animals and the relationship between serum 25(OH)D concentrations and markers of inflammation. The hypothesis of this thesis was that vitamin status D would negatively correlate with presence of disease, markers of inflammation and disease outcomes. As similar findings have been demonstrated in human medicine, the hypothesis was that cats and dogs would be suitable models to investigate the role of vitamin D in human disease. This thesis demonstrates that in dogs with a CE serum 25(OH)D concentrations are negatively correlated with inflammation and are predictive of clinical outcomes. Vitamin D status was also lower in cats with FIV and importantly vitamin D status was predictive of short term mortality in hospitalised ill cats. This research will be of interest to veterinary surgeons and opens the possibility for clinical trials which examine if low vitamin D status is causally associated with ill health and whether vitamin D supplementation results in superior treatment outcomes in companion animals. This thesis also demonstrates the potential of cats and dogs as model systems in which to examine the role of vitamin D in human health.en
dc.language.isoenen
dc.publisherThe University of Edinburghen
dc.relation.hasversionTitmarsh H, Kilpatrick S, Sinclair J, Boag A, Bode EF, Lalor SM, et al. (2015) Vitamin D Status Predicts 30 Day Mortality in Hospitalised Cats. PLoS ONE 10(5): e0125997. doi:10.1371/journal. pone.0125997en
dc.relation.hasversionLalor S, Schwartz AM, Titmarsh H, Reed N, Tasker S, Boland L, et al. Cats with Inflammatory Bowel Disease and Intestinal Small Cell Lymphoma Have Low Serum Concentrations of 25-Hydroxyvitamin D. Journal of Veterinary Internal Medicine. 2014; 28(2):351–5. doi: 10.1111/jvim.12294 PMID: 24433362en
dc.relation.hasversionH. Titmarsh, A.G. Gow, S. Kilpatrick, J. Sinclair, T. Hill, E. Milne, A. Philbey, J. Berry, I. Handel, and R.J. Mellanby, Association of Vitamin D Status and Clinical Outcome in Dogs with a Chronic Enteropathy, J Vet Intern Med 2015en
dc.relation.hasversionTitmarsh HF, Gow AG, Kilpatrick S, Cartwright JA, Milne EM, Philbey AW, et al. (2015) Low Vitamin D Status Is Associated with Systemic and Gastrointestinal Inflammation in Dogs with a Chronic Enteropathy. PLoS ONE 10(9): e0137377. doi:10.1371/journal.pone.0137377en
dc.subjectvitamin Den
dc.subjectfeline immunodeficiency virusen
dc.subjectFIVen
dc.subjectenteropathyen
dc.subjectinflammationen
dc.subjectcatsen
dc.subjectdogsen
dc.titleInvestigation of vitamin D metabolism in non-skeletal disorders of companion animalsen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelMastersen
dc.type.qualificationnameMSc(R) Master of Science by Researchen


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