Evaluation of intestinal permeability and gluten sensitivity in Soft-Coated Wheaten Terriers with familial protein-losing enteropathy, protein-losing nephropathy, or both

Grape seed proanthocyanidin improves intestinal inflammation in canine through regulating gut microbiota and bile acid compositions

Although certain progress has been made in treating canine inflammatory bowel disease (IBD), a large proportion of dogs have a poor prognosis and may develop resistance and side effects. Therefore, it is of great significance to prevent or alleviate canine IBD through nutritional intervention. Plant polyphenol can interact with intestinal bacteria and has important prospects in the intestinal health improvement. This study evaluated the effect of grape seed proanthocyanidin (GSP), a plant-derived natural polyphenol, on Labrador Retrievers with mild IBD. In Experiment 1 of this study, GSP alleviated persistent intestinal inflammation in canines by improving inflammatory indexes and reducing intestinal permeability. Moreover, GSP treatment increased the abundance of bacteria with potential anti-inflammatory properties and engaging bile acid metabolism, including Ruminococcaceae, Faecalibacterium, Ruminococcus_torques_group, and Lachnospiraceae_NK4A136_group. Notably, targeted metabolomic analysis identified elevated productions of fecal chenodeoxycholic acid and its microbial transformation product lithocholic acid, which might contribute to relieving canine intestinal inflammation. Further, in Experiment 2, fecal microbiota transplantation was used to determine whether gut microbiota is a potential mechanism for GSP efficacy. Dogs with mild IBD received the fecal microbiota from the group administered GSP and mirrored the improvement effects of GSP, which results verified that gut microbial alteration could be an underlying mechanism for GSP efficiency on canine IBD. Our findings highlight that the mechanism of the GSP function on canine IBD is mediated by altering gut microbial composition and improving bile acid metabolism. This study proposes a natural polyphenol-based dietary strategy for improving canine intestinal health.

Current diagnostics for chronic enteropathies in dogs

Chronic enteropathies (CEs) in dogs describe a group of idiopathic disorders characterized by chronic persistent or recurrent gastrointestinal (GI) signs. Three major subgroups of CE can be identified by their response to treatment: Food-responsive disease (FRD), antibiotic-responsive disease (ARD), and steroid-responsive disease (SRD). The clinical diagnosis of CE is made by exclusion of all other possible causes of chronic diarrhea and includes histologic assessment of intestinal biopsies. The process of diagnosing canine CE can therefore be very time-consuming and expensive, and in most cases, does not help to identify dogs that will respond to a specific treatment. The development of novel diagnostic tests for canine CE has therefore focused on the accuracy of such tests to predict treatment responses. In this article, several novel assays that have the potential to become commercially available will be discussed, such as genetic tests, perinuclear anti-neutrophil cytoplasmic antibodies (pANCA), antibodies against transglutaminase/gliadin, antibodies against E coli OmpC/flagellin, and micro RNAs.

Serological markers of gluten sensitivity in Border terriers with gall bladder mucocoeles

OBJECTIVES

To evaluate serological markers of gluten sensitivity in conjunction with cholecystokinin measurement in Border terriers with gall bladder mucocoeles.

MATERIALS AND METHODS

Medical records from two referral hospitals were obtained between 2011 and 2019 to identify Border terriers with gall bladder mucocoeles, non-Border terriers with gall bladder mucocoeles and control Border terriers with non-biliary diseases. Enzyme-linked immunosorbent assays were performed on stored fasted serum samples for anti-gliadin IgG, anti-canine transglutaminase-2-IgA autoantibodies and cholecystokinin. Statistical analysis was performed using the Kruskall-Wallis test to identify differences between the groups.

RESULTS

Fifteen Border terriers with gall bladder mucocoeles, 17 non-Border terriers with gall bladder mucocoeles and 14 control Border terriers with non-biliary diseases were recruited. Median transglutaminase-2-IgA autoantibodies in Border terriers with gall bladder mucocoeles was 0.73 (range: 0.18 to 1.67), which was significantly greater than in control Border terriers at 0.41 (0.07 to 1.14). Median cholecystokinin concentration in Border terriers with gall bladder mucocoeles was 13 pg/mL (6 to 45 pg/mL), which was significantly lower than in control Border terriers at 103 pg/mL (9 to 397 pg/mL). There was no difference in the anti-gliadin IgG between these groups. There was no difference observed in the non-Border terriers with gall bladder mucocoeles with either of the other groups.

CLINICAL SIGNIFICANCE

Reduced cholecystokinin and increased transglutaminase-2-IgA autoantibodies was detected in Border terriers with gall bladder mucocoeles; which is in part homologous to gall bladder disease identified in human coeliac disease. The results suggest an immunological disease with impaired cholecystokinin release may be affecting gall bladder motility and possibly contributing to mucocoele formation in Border terriers.

Glomerulopathy and mutations in NPHS1 and KIRREL2 in soft-coated Wheaten Terrier dogs

Dogs of the soft-coated wheaten terrier breed (SCWT) are predisposed to adult-onset, genetically complex, protein-losing nephropathy (average onset age = 6.3 ± 2.0 years). A genome-wide association study using 62 dogs revealed a chromosomal region containing three statistically significant SNPs (p(raw) ≤ 4.13 × 10(-8); p(genome) ≤ 0.005) when comparing DNA samples from affected and geriatric (≥14 years) unaffected SCWTs. Sequencing of candidate genes in the region revealed single nucleotide changes in each of two closely linked genes, NPHS1 and KIRREL2, which encode the slit diaphragm proteins nephrin and Neph3/filtrin, respectively. In humans, mutations in nephrin and decreased expression of Neph3 are associated with podocytopathy and protein-losing nephropathy. The base substitutions change a glycine to arginine in the fibronectin type 3 domain of nephrin and a proline to arginine in a conserved proline-rich region in Neph3. These novel mutations are not described in other species, nor were they found in 550 dogs of 105 other breeds, except in 3 dogs, including an affected Airedale terrier, homozygous for both substitutions. Risk for nephropathy is highest in dogs homozygous for the mutations (OR = 9.06; 95 % CI = 4.24-19.35). This is the first molecular characterization of an inherited podocytopathy in dogs and may serve as a model for continued studies of complex genetic and environmental interactions in glomerular disease.

Prevalence of perinuclear antineutrophilic cytoplasmic autoantibodies in serum of healthy Soft Coated Wheaten Terriers in the United Kingdom

OBJECTIVE

To estimate the prevalence of perinuclear antineutrophilic cytoplasmic autoantibodies (pANCA) in the serum of healthy Soft Coated Wheaten Terriers (SCWTs) in the United Kingdom and to identify potential risk factors and heritability patterns associated with a positive result for pANCA.

ANIMALS

188 SCWTs (age range, 18 months to 14.3 years).

PROCEDURES

Blood samples were obtained from SCWTs in various locations in England. Serum was tested for pANCA by use of an immunofluorescence assay, and total protein and albumin concentrations were determined. Pedigrees were evaluated to identify close relatives that had protein-losing enteropathy (PLE) or protein-losing nephropathy (PLN).

RESULTS

39 of 188 (20.7%) dogs, including young dogs, had positive results for pANCA. Dogs had significantly higher odds of having positive results for pANCA if they had at least 1 littermate that had PLE or PLN (odds ratio, 12.1) or if they had at least 1 full sibling from another litter known to be affected with PLE or PLN (odds ratio, 4.0). CONCLUSIONS AND CLINICAL RELEVANCE; This study revealed a high prevalence of pANCA in the serum of a representative sample of healthy SCWTs in the United Kingdom and a significant association between positive results for pANCA and a diagnosis of PLE or PLN in a sibling.

Laboratory tests for diagnosis of gastrointestinal and pancreatic diseases

The panel of laboratory tests available for diagnosis of gastrointestinal (GI) diseases in dogs and cats is wide, and, recently, several new tests have been developed. This article will focus on advances in laboratory tests that are available for the general practitioner for diagnosis of GI diseases. Laboratory tests for diagnosis of gastric and intestinal infectious diseases include fecal parasite screening tests, enzyme-linked immunosorbent assays for parvoviral enteritis, and some specific bacterial tests like fluorescent in situ hybridization for identification of specific bacteria attached to the intestinal epithelial cells. Serum concentrations of folate and cobalamin are markers of intestinal absorption, but are also changed in exocrine pancreatic insufficiency and intestinal bacterial overgrowth. Hypocobalaminemia is common in GI and pancreatic disease. Decreased serum trypsin-like immunoreactivity is a very sensitive and specific test for the diagnosis of exocrine pancreatic insufficiency in dogs and cats. Serum pancreatic lipase is currently the most sensitive and specific test to identify pancreatic cell damage and acute pancreatitis. However, serum canine pancreas-specific lipase is less sensitive in canine chronic pancreatitis. Increased serum trypsin-like immunoreactivity is also specific for pancreatic damage but is less sensitive. It is very likely that further studies will help to better specify the role of these new tests in the diagnosis of canine and feline pancreatic diseases.

Two-dimensional grayscale ultrasound and spectral Doppler waveform evaluation of dogs with chronic enteropathies

Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.

The canine model of dietary hypersensitivity

IgE-mediated dietary hypersensitivity affects approximately 1% of the canine population. There are no breed associations and < or =50% of the patients are aged <1 year at presentation. The most common causative allergens are beef, chicken, milk, eggs, maize, wheat and soyabean. Affected dogs generally display cutaneous disease and 10-15% of the patients may have concurrent alimentary involvement. Diagnosis is currently based on dietary restriction followed by provocation. Procedures for the detection of serum allergen-specific IgE and IgG antibodies are widely available, but these tests correlate poorly with clinical presentation and dietary testing. Recent studies have demonstrated the allergen specificity of IgE antibodies by immunoblotting and have described blood lymphocyte proliferative responses to food allergens. In addition to investigations of spontaneously-arising dietary hypersensitivity, it has also proved possible to study this disorder experimentally. Small colonies of dogs sensitive to particular dietary proteins have been used to study clinical and serological responses to allergen challenge. Hypersensitivity has been experimentally induced in dogs of an atopic phenotype by repeated subcutaneous injection of alum-adjuvanted dietary allergen during neonatal life. These models have been used to trial a range of modified protein or hydrolysate diets. The dog provides a unique large-animal model for investigation of the immunopathogenesis of human dietary hypersensitivity. The dog is closely related genetically to man and shares environmental disease triggers with man. Spontaneously arising canine dietary hypersensitivity is a good clinical mimic of the human disease, and ability to therapeutically manipulate this adverse response in the dog might lead to benefits for human patients.

Evaluation of gastrointestinal permeability and mucosal absorptive capacity in dogs with chronic enteropathy

OBJECTIVE

To assess intestinal mucosal function by measuring permeability and absorptive capacity in dogs with chronic enteropathy (CE) before and after treatment and to determine whether those variables were correlated with clinical disease activity or histologic scoring of intestinal biopsy specimens.

ANIMALS

29 dogs with CE.

PROCEDURE

Dogs were designated as having dietresponsive CE or CE requiring glucorticoid treatment. Severity of clinical signs was assessed by calculating the canine inflammatory bowel disease activity index (CIBDAI). Histologic severity of intestinal infiltration was assessed before and after 4 weeks of treatment in the diet-responsive group and before and after 10 weeks of treatment in the glucocorticoid group. Gastrointestinal permeability and mucosal absorptive capacity were assessed by use of intragastric administration of a solution containing lactulose, rhamnose, xylose, 3-O-methylglucose, and sucrose. Urine was collected 6 hours after administration of the sugar solution to determine urinary lactulose-to-rhamnose (L:R), xylose-to-methylglucose (X:M), and sucrose-to-methylglucose (S:M) ratios.

RESULTS

Median CIBDAI scores decreased significantly in both groups of dogs after treatment. However, the median histologic grade of intestinal biopsy specimens did not change with treatment in either group. There were no significant differences in L:R, X:M, or S:M ratios after treatment in either group and no significant correlations between L:R, X:M, or S:M ratios and CIBDAI or histologic scores.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of tests for intestinal permeability and mucosal absorptive capacity were not useful indicators of clinical disease activity as assessed by the CIBDAI or the sever ity of infiltration as indicated by histologic evaluation.

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions

OBJECTIVE

To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy.

METHODS

Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs.

RESULTS

When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs.

CLINICAL SIGNIFICANCE

The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.

Fecal alpha1-proteinase inhibitor concentration in dogs with chronic gastrointestinal disease

BACKGROUND

Fecal alpha(1)-proteinase inhibitor (alpha(1)-PI) clearance is a reliable, noninvasive marker for protein-losing enteropathy in human beings. An assay for use in dogs has been developed and validated.

OBJECTIVE

The aim of this study was to evaluate fecal alpha(1)-PI concentration in dogs with chronic gastrointestinal disease, compared with healthy dogs, and to assess its correlation with serum albumin concentration.

METHODS

Fecal samples were collected from 2 groups of dogs. Group 1 consisted of 21 clinically healthy client-owned dogs without signs of gastrointestinal disease. Group 2 consisted of 16 dogs referred for investigation of suspected gastrointestinal disease. On the basis of gastric and duodenal biopsies, group 2 was further subdivided into dogs with normal histology (n = 9) and those with histologic abnormalities (n = 7: inflammatory bowel disease, n = 3; lymphangiectasia, n = 4). An ELISA was used to measure alpha(1)-PI concentrations in fecal extracts.

RESULTS

Fecal alpha(1)-PI concentrations, expressed as micro g/g of feces, were not significantly different between groups 1 and 2 as a whole. However, fecal alpha(1)-PI concentrations (median, minimum-maximum) were significantly higher in dogs with gastrointestinal diseases associated with histologic abnormalities (60.6 micro g/g, 7.4-201.7 micro g/g) compared with dogs with normal histology (3.8 micro g/g, 0.7-74.0 micro g/g) and control dogs (9.9 micro g/g, 0.0-32.1 micro g/g). There was no significant correlation between fecal alpha(1)-PI and serum albumin concentrations in dogs with gastrointestinal disease.

CONCLUSIONS

Increased fecal alpha(1)-PI concentration may signal the need to obtain gastrointestinal biopsies for a final diagnosis. Fecal alpha(1)-PI concentration may be a useful test for early detection of protein-losing enteropathy before decreases in serum albumin concentration can be detected.

Fecal alpha1-proteinase inhibitor concentration in dogs receiving long-term nonsteroidal anti-inflammatory drug therapy

BACKGROUND

Fecal alpha(1)-proteinase inhibitor (alpha(1)-PI) clearance is a reliable, noninvasive marker for protein-losing enteropathy (PLE) in human beings. An assay for measurement of this protein in the dog has been developed and validated and may be useful for the investigation of gastrointestinal disease in this species. Nonsteroidal anti-inflammatory drugs (NSAIDs) frequently are administered to dogs and may have adverse effects on the gastrointestinal tract, including gastroduodenal ulceration and altered mucosal permeability. The value of fecal alpha(1)-PI measurement in detecting unrelated gastrointestinal disease may be limited in dogs on NSAID therapy, but alpha(1)-PI may be a useful marker for NSAID-induced gastrointestinal damage.

OBJECTIVE

The aim of this study was to evaluate the effects of long-term administration of NSAIDs on fecal alpha(1)-PI concentrations in dogs.

METHODS

Fecal samples were collected from 2 groups of dogs: 1) 21 clinically-healthy client-owned dogs without signs of gastrointestinal disease and receiving no NSAIDs and 2) 7 dogs referred for investigation and treatment of orthopedic disorders; the dogs had received either meloxicam or carprofen daily for at least 30 days. Fecal alpha(1)-PI concentration was measured by ELISA.

RESULTS

Fecal alpha(1)-PI concentrations, expressed as micro g/g of feces, were not significantly different between groups 1 and 2 (median [range], group 1: 9.9 micro g/g [0.0-32.1 micro g/g]; group 2: 5.6 micro g/g [1.1-32.3 micro g/g]; P =.81).

CONCLUSIONS

These results suggest that use of cyclooxygenase-2-selective NSAIDs, such as carprofen and meloxicam, does not significantly affect fecal alpha(1)-PI measurements. However, study numbers were small, and larger prospective trials are required to assess more accurately the gastrointestinal effects of NSAIDs in dogs.