Peter-John M. Noble

Metabolomics: an emerging post-genomic tool for nutrition

The post-genomic era has been driven by the development of technologies that allow the function of cells and whole organisms to be explored at the molecular level. Metabolomics is concerned with the measurement of global sets of low-molecular-weight metabolites. Metabolite profiles of body fluids or tissues can be regarded as important indicators of physiological or pathological states. Such profiles may provide a more comprehensive view of cellular control mechanisms in man and animals, and raise the possibility of identifying surrogate markers of disease. Metabolomic approaches use analytical techniques such as NMR spectroscopy and MS to measure populations of low-molecular-weight metabolites in biological samples. Advanced statistical and bioinformatic tools are then employed to maximise the recovery of information and interpret the large datasets that are generated. Metabolomics has already been used to study toxicological mechanisms and disease processes and offers enormous potential as a means of investigating the complex relationship between nutrition and metabolism. Examples include the metabolism of dietary substrates, drug-induced disturbances of lipid metabolites in type 2 diabetes mellitus and the therapeutic effects of vitamin supplementation in the treatment of chronic metabolic disorders.

Metabolomics as a diagnostic tool for hepatology: validation in a naturally occurring canine model

Human hepatopathies are a diagnostic challenge, with many distinct diseases having similar clinical signs and laboratory findings. Naturally occurring canine hepatic disease provides an excellent model for human diseases and similar diagnostic dilemmas exist; differentiating canine congenital portosystemic vascular anomalies (PVA) from acquired hepatopathies is difficult and traditionally requires invasive diagnostic procedures. The emerging post-genomic science of metabolomics is concerned with detecting global changes of populations of endogenous low molecular weight metabolites in biological samples and offers the possibility of identifying surrogate profiles of disease. Metabolomics couples sensitive metabolite analysis with sophisticated pattern recognition techniques. In this study, a metabolomic strategy has been employed to assess metabolite changes in the plasma of dogs with congenital PVA and acquired hepatic disease. Plasma samples were collected from 25 dogs, comprising 9 dogs with congenital PVA, 6 with acquired hepatopathy and 10 with non-hepatic disorders. Low molecular weight metabolites were analyzed by liquid chromatography-mass spectrometry (LC-MS). Following identification of metabolites, multivariate data analysis was used to compare profiles amongst groups. The analysis demonstrated significant disturbances in the plasma bile acid and phospholipid profiles of dogs with portovascular anomalies. In contrast to traditional laboratory parameters, the metabolomic strategy was able to produce a clear segregation between all three study groups. In conclusion, this study demonstrates the potential of metabolomics as a diagnostic tool for naturally occurring hepatic disease. With further validation, this approach will improve diagnostic capabilities, provide an insight into pathogenetic mechanisms, and ultimately inform therapeutic decision making in clinical hepatology.

Surveillance of diarrhoea in small animal practice through the Small Animal Veterinary Surveillance Network (SAVSNET)

Using the Small Animal Veterinary Surveillance Network (SAVSNET), a national small animal disease-surveillance scheme, information on gastrointestinal disease was collected for a total of 76 days between 10 May 2010 and 8 August 2011 from 16,223 consultations (including data from 9115 individual dogs and 3462 individual cats) from 42 premises belonging to 19 UK veterinary practices. During that period, 7% of dogs and 3% of cats presented with diarrhoea. Adult dogs had a higher proportional morbidity of diarrhoea (PMD) than adult cats (P <0.001). This difference was not observed in animals <1 year old. Younger animals in both species had higher PMDs than adult animals (P < 0.001). Neutering was associated with reduced PMD in young male dogs. In adult dogs, miniature Schnauzers had the highest PMD. Most animals with diarrhoea (51%) presented having been ill for 2-4 days, but a history of vomiting or haemorrhagic diarrhoea was associated with a shorter time to presentation. The most common treatments employed were dietary modification (66% of dogs; 63% of cats) and antibacterials (63% of dogs; 49% of cats). There was variability in PMD between different practices. The SAVNET methodology facilitates rapid collection of cross-sectional data regarding diarrhoea, a recognised sentinel for infectious disease, and characterises data that could benchmark clinical practice and support the development of evidence-based medicine.

Efficacy of en bloc ligation of the thoracic duct: descriptive study in 14 dogs.

OBJECTIVE To assess whether en bloc ligation of all caudal mediastinal tissue between the aorta and thoracic vertebrae will occlude all branches of the thoracic duct. STUDY DESIGN Descriptive study. ANIMALS Canine cadavers (n=15). METHODS The cisterna chyli was approached through a right paralumbar abdominal incision and cannulated. A right 10th intercostal thoracotomy was performed and the tissue of the caudal mediastinum dorsal to the aorta and ventral to the thoracic vertebrae was ligated. Radio-opaque contrast material was injected into the cisterna chyli during fluoroscopic imaging of the thorax and cranial abdomen. Still images were obtained before and after contrast injection and a subtraction image produced. Gray values were measured from these images, cranial and caudal to the ligature site. RESULTS Cannulation of the cisterna chyli in 1 cadaver was impossible and it was, therefore, excluded. In 13 (93%) cadavers contrast material did not pass cranial to the ligature site. In 1 cadaver, an intact thoracic duct was identified on lymphangiography outside the en bloc ligation. CONCLUSION En bloc ligation of the caudal mediastinal tissue dorsal to the aorta was successful in preventing opacification with contrast material of all branches of the thoracic duct in 93% of cadavers. CLINICAL RELEVANCE En bloc ligation is successful in 93% of cadavers and reduces the operative time compared with techniques requiring some type of mesenteric lymphangiography to aid identification of the thoracic duct.

Control of c-fos expression in STC-1 cells by peptidomimetic stimuli.

Enteroendocrine cells respond to nutrient and non-nutrient stimuli in the gut lumen. The intestinal hormone cholecystokinin (CCK) is secreted in response to luminal fatty acids, amino acids, peptides and proteins. The peptidomimetic cephalosporins have been reported to provide model, stable, compounds with similar secretagogue activity to peptide. Putative luminal stimuli also influence transcriptional activity in enteroendocrine cells, but the mechanisms are uncertain. In the present study we have investigated the control of c-fos expression in STC-1 cells (an enteroendocrine cell line). Peptidomimetics stimulated calcium-dependent release of CCK, and increased intracellular calcium, phosphorylation of p42/44 mitogen-activated protein kinase (MAP kinase) and c-fos mRNA abundance. Hypotonic stress also increased p42/44 MAP kinase phosphorylation and c-fos mRNA, but not CCK release. The increase in c-fos mRNA was strikingly potentiated by peptidomimetics in hypotonic medium. Increased c-fos expression, but not CCK release, was suppressed by the MAP kinase (MEK) inhibitor PD98059, and by the tyrosine kinase inhibitor genistein. We conclude that in STC-1 cells, peptidomimetics act through the p42/44 MAP kinase pathway to increase c-fos expression but not exocytosis. Moreover, a putative non-nutritive stimulus, hypotonic stress, may interact with this pathway to enhance c-fos expression, independently of hormone release.

Comparison of a chlorambucil-prednisolone combination with an azathioprine-prednisolone combination for treatment of chronic enteropathy with concurrent protein-losing enteropathy in dogs: 27 cases (2007-2010)

OBJECTIVE To compare treatment protocols for chronic enteropathy and concurrent protein-losing enteropathy that used prednisolone in conjunction with either azathioprine or chlorambucil in dogs. DESIGN Retrospective case series. ANIMALS 27 dogs. PROCEDURES All dogs had hypoalbuminemia (serum albumin concentration, < 18.0 g/L) and chronic enteropathy as diagnosed via complete gastrointestinal tract investigations including intestinal biopsy. Dogs received either an azathioprine-prednisolone combination (group A; n = 13) or a chlorambucil-prednisolone combination (group C; 14). Response to treatment was assessed by evaluation of body weight gain, serum albumin concentration, and duration of primary treatment. RESULTS No significant pretreatment differences were detected between groups for any baseline variable (signalment and weight), clinicopathologic variable (albumin, cobalamin, and folate concentrations), or histopathologic findings. After treatment, serum albumin concentration and weight gain were significantly greater in group C. Median survival time for group A dogs was 30 days (95% confidence interval, 15 to 45 days) and was not reached for group C dogs. Duration of primary treatment was positively associated with the histopathologic presence of mild lacteal dilatation and use of a chlorambucil-prednisolone combination. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that a chlorambucil-prednisolone protocol is more efficacious for treatment of chronic enteropathy and concurrent protein-losing enteropathy, compared with an azathioprine-prednisolone combination. Given these findings, a prospective randomized clinical trial is warranted.

How often do primary care veterinarians record the overweight status of dogs

Obesity is a prevalent medical condition in dogs caused by the excess accumulation of fat, with negative effects on quality of life, longevity and the risk of developing associated pathologies. However, it is unclear how frequently first-opinion veterinarians record dogs as overweight (OW) or obese in medical records, and what factors determine when they do. Data sourced through the Small Animal Surveillance Network were used to determine the relative frequency of recording OW status (obesity or OW) in dogs presented to the UK first-opinion practices. Cases were identified using a search of clinical record-free text for relevant keywords. A case–control study was then conducted, comparing dogs where the OW status was recorded with a control group of obese dogs with no diagnosis recorded. Of 49 488 consultations, the OW status was recorded in 671 dogs (relative frequency 1·4 %). Using multiple logistic regression, the OW status of a dog was more likely to be recorded when the consultation was for osteoarthritis (OR 5·42; 95 % CI 2·09, 14·07; P < 0·001) or lameness (OR 2·02; 95 % CI 1·20, 3·42; P = 0·006). Furthermore, the OW status was more commonly recorded in dogs that were members of a practice health scheme (OR 5·35; 95 % CI 1·57, 18·17; P = 0·04) and less commonly recorded in microchipped dogs (OR 0·43; 95 % CI 0·41, 0·91; P = 0·02). These results suggest that OW and obesity are underdiagnosed in the first-opinion practice. However, a presentation for orthopaedic disease appears a key prompt for recording the OW status. Further studies are now warranted to determine the reasons for such marked underdiagnosis.

Patterns of antimicrobial agent prescription in a sentinel population of canine and feline veterinary practices in the United Kingdom

Highlights • Antimicrobial agent prescription was monitored in a large UK population of cats and dogs over a 2 year period (2014–2016).• Systemic antimicrobial agents were prescribed more frequently to cats; topical prescription was more frequent in dogs.• A temporal reduction (2014–2016) in antimicrobial agent prescription was observed in both cats and dogs in this population.• Premises which prescribed antimicrobial agents commonly to cats generally also prescribed commonly to dogs.• The most frequently prescribed antibiotics were cefovecin in cats and clavulanic acid potentiated amoxicillin in dogs.

Demographics of dogs, cats, and rabbits attending veterinary practices in Great Britain as recorded in their electronic health records

BackgroundUnderstanding the distribution and determinants of disease in animal populations must be underpinned by knowledge of animal demographics. For companion animals, these data have been difficult to collect because of the distributed nature of the companion animal veterinary industry. Here we describe key demographic features of a large veterinary-visiting pet population in Great Britain as recorded in electronic health records, and explore the association between a range of animal’s characteristics and socioeconomic factors.ResultsElectronic health records were captured by the Small Animal Veterinary Surveillance Network (SAVSNET), from 143 practices (329 sites) in Great Britain. Mixed logistic regression models were used to assess the association between socioeconomic factors and species and breed ownership, and preventative health care interventions. Dogs made up 64.8% of the veterinary-visiting population, with cats, rabbits and other species making up 30.3, 2.0 and 1.6% respectively. Compared to cats, dogs and rabbits were more likely to be purebred and younger. Neutering was more common in cats (77.0%) compared to dogs (57.1%) and rabbits (45.8%). The insurance and microchipping relative frequency was highest in dogs (27.9 and 53.1%, respectively). Dogs in the veterinary-visiting population belonging to owners living in least-deprived areas of Great Britain were more likely to be purebred, neutered, insured and microchipped. The same association was found for cats in England and for certain parameters in Wales and Scotland.ConclusionsThe differences we observed within these populations are likely to impact on the clinical diseases observed within individual veterinary practices that care for them. Based on this descriptive study, there is an indication that the population structures of companion animals co-vary with human and environmental factors such as the predicted socioeconomic level linked to the owner’s address. This ‘co-demographic’ information suggests that further studies of the relationship between human demographics and pet ownership are warranted.

A blinded randomised controlled trial to determine the effect of enteric coating on enzyme treatment for canine exocrine pancreatic efficiency.

BackgroundEnzyme treatment is the mainstay for management of exocrine pancreatic insufficiency (EPI) in dogs. ‘Enteric-coated’ preparations have been developed to protect the enzyme from degradation in the stomach, but their efficacy has not been critically evaluated. The hypothesis of the current study was that enteric coating would have no effect on the efficacy of pancreatic enzyme treatment for dogs with EPI.Thirty-eight client-owned dogs with naturally occurring EPI were included in this multicentre, blinded, randomised controlled trial. Dogs received either an enteric-coated enzyme preparation (test treatment) or an identical preparation without the enteric coating (control treatment) over a period of 56 days.ResultsThere were no significant differences in either signalment or cobalamin status (where cobalamin deficient or not) between the dogs on the test and control treatments. Body weight and body condition score increased in both groups during the trial (P<0.001) but the magnitude of increase was greater for the test treatment compared with the control treatment (P<0.001). By day 56, mean body weight increase was 17% (95% confidence interval 11-23%) in the test treatment group and 9% (95% confidence interval 4-15%) in the control treatment group. The dose of enzyme required increased over time (P<0.001) but there was no significant difference between treatments at any time point (P=0.225). Clinical disease severity score decreased over time for both groups (P=0.011) and no difference was noted between groups (P=0.869). No significant adverse effects were reported, for either treatment, for the duration of the trial.ConclusionsEnteric coating a pancreatic enzyme treatment improves response in canine EPI.