Detection of apoptotic cells in intestines from horses with and without gastrointestinal tract disease

OBJECTIVE: To identify apoptosis in equine intestines and determine whether apoptosis is associated with gastrointestinal tract disease or a specific tissue layer of intestine. ANIMALS: 38 horses that underwent surgery or were euthanatized for small or large intestine obstruction, strangulation, or distension and 9 control horses euthanatized for reasons other than gastrointestinal tract disease or systemic disease. PROCEDURE: Specimens were collected at surgery from intestine involved in the primary lesion and distant to the primary lesion site or at necropsy from several sites including the primary lesion site. Histologic tissue sections were stained with H&E, and apoptosis was detected by use of the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. The number of apoptotic cells per hpf was counted in the mucosa, circular muscle, longitudinal muscle, and serosa. RESULTS: Apoptotic nuclei were seen in all layers of intestine. An increased number of apoptotic cells was found in the circular muscle of the intestine from horses with simple obstruction, compared with strangulating obstruction or healthy intestine. Intestine distant from a primary strangulating lesion had higher numbers of apoptotic cells than did intestine distant from a simple obstructive lesion or intestine taken at the site of a strangulating or simple obstructive lesion. CONCLUSIONS AND CLINICAL RELEVANCE: Intestine from horses with obstructing or strangulating lesions in the small intestine and large colon had high numbers of apoptotic cells possibly because of ischemic cell injury and subsequent inflammation. Whether substantial apoptosis affects intestinal function is not yet known.     

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

Background: Fecal α₁‐proteinase inhibitor (α₁‐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 α₁‐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 α₁‐PI concentrations in fecal extracts. Results: Fecal α₁‐PI concentrations, expressed as μg/g of feces, were not significantly different between groups 1 and 2 as a whole. However, fecal α₁‐PI concentrations (median, minimum‐maximum) were significantly higher in dogs with gastrointestinal diseases associated with histologic abnormalities (60.6 μg/g, 7.4–201.7 μg/g) compared with dogs with normal histology (3.8 μg/g, 0.7–74.0 μg/g) and control dogs (9.9 μg/g, 0.0–32.1 μg/g). There was no significant correlation between fecal α₁‐PI and serum albumin concentrations in dogs with gastrointestinal disease. Conclusions: Increased fecal α₁‐PI concentration may signal the need to obtain gastrointestinal biopsies for a final diagnosis. Fecal α₁‐PI concentration may be a useful test for early detection of protein‐losing enteropathy before decreases in serum albumin concentration can be detected.     

Retrospective review of carvedilol administration in 38 dogs with preclinical chronic valvular heart disease

ObjectivesReport the effect of carvedilol administration on clinical and echocardiographic parameters and outcome in dogs with preclinical (ACVIM Stage B) chronic valvular heart disease (CVD).Animals, materials and methodsRetrospective case series of 38 client-owned dogs.Demographic, physical examination and diagnostic imaging findings, blood pressure (BP), administration details and outcome were obtained from medical records of dogs receiving carvedilol for preclinical CVD. When possible, additional follow-up information was obtained through telephone interviews with referring veterinarians and owners.ResultsBaseline data and follow-up were evaluated. Median and interquartile range (IQR) for age and weight were 8.6 (7.2–10.8) years and 8.5 (7.6–9.6) kg. 14/38 were male; 33/38 were Cavalier King Charles Spaniels; 33/38 had Stage B2 CVD. The initial dose of carvedilol was 0.31 (0.26–0.35) mg/kg PO twice daily. The carvedilol dose achieved following up titration was 1.11 (0.81–1.32) mg/kg twice daily. No adverse effects were recorded during up titration. Median survival for all dogs was 48.5 months with a 95% CI of 38.3–58.6.ConclusionsThis study suggests that carvedilol at the dose reported herein is well tolerated in small breed dogs with preclinical CVD. Prospective studies to evaluate efficacy are warranted.     

Characterization of mast cell numbers and subtypes in biopsies from the gastrointestinal tract of dogs with lymphocytic-plasmacytic or eosinophilic gastroenterocolitis

It has been suggested but not proven that hypersensitivity type I reactions are involved in the pathogenesis of canine inflammatory bowel disease (IBD). The main effector cells in type I hypersensitivity reactions are mast cells (MCs). Canine MCs, as human MCs, can be subdivided into three subtypes according to their content of mast cell-specific proteases: tryptase (MC_T), chymase (MC_C), or tryptase and chymase bearing MCs (MC_TC). In this study, numbers and subsets of mast cells were investigated in biopsies from the gastrointestinal tract of dogs with histopathologically confirmed lymphocytic-plasmacytic enteritis (LPE) (n = 4), lymphocytic-plasmacytic colitis (LPC) (n = 1) and eosinophilic gastroenterocolitis (EGE) (n = 11). Paraffin sections of formalin-fixed samples from the stomach, small intestine (duodenum, jejunum, ileum) and colon were stained by using a metachromatic staining method (kresylecht-violet; KEV) and a combined enzyme histochemical and immunohistochemical technique for chymase and tryptase. Additionally, immunohistochemistry with antibodies against T cells (CD3), macrophages (myeloid/histiocyte antigen) and IgA, IgG and IgM bearing cells was conducted. Quantitative evaluation of mast cells and semiquantitative scoring of immunohistochemically stained cells were performed. Between the two histopathologically defined groups clear differences concerning mast cell numbers were detected. In most affected intestinal tissue locations of dogs with LPE/LPC a decrease in metachromatically (kresylecht-violet) stained granule-containing MCs and immunohistochemically stained MC_T,C,TC was found. This reduction could be due to mast cell degranulation, a T helper cell 1 dominated reaction pattern or a “thinning out” due to increasing T cells, IgA and IgG bearing cells. Dogs with EGE displayed higher variability in mast cell numbers but most of the affected large and small intestinal locations had increased numbers of MCs. In these cases, T cells, IgA bearing cells and macrophages also increased. Increased numbers of MCs and eosinophils seen in the intestinal mucosa of dogs with EGE could indicate the presence of a type I hypersensitivity reaction (T helper cell 2 pattern) in response to dietary antigens. Changes in cell numbers occurred also in unaffected locations of dogs with LPE/LPC and EGE which showed reduced MC_T,C,TC, increased KEV positive cells and partially increased leucocytes and macrophages.     

Adherent gram-positive cocci on the intestinal villi of two dogs with gastrointestinal disease

Two dogs were examined for clinical signs of chronic gastrointestinal disease. Duodenal mucosal biopsy specimens, obtained endoscopically, revealed histologic lesions of adherent gram-positive cocci on the villus epithelium of both dogs. The positive gram stain and morphologic features of the adherent cocci were suggestive of Streptococcus organisms. Indirect tests for intestinal bacterial overgrowth were not diagnostic, suggesting that the adherent cocci were a primary lesion. Rapid clinical response following dietary manipulation and the initiation of medical management was observed in both dogs. The dogs of this report draw similarities to Streptococcus durans infection previously reported in pigs, foals, and a single pup. The pathogenesis of enteric disease associated with adherent gram-positive cocci in dogs remains ill-defined.     

Retrospective evaluation of repeat celiotomy in 53 horses with acute gastrointestinal disease

Fifty-three of 648 horses (8.2%) treated surgically for acute gastrointestinal obstruction were subjected to repeat celiotomy. Forty horses (75%) recovered from anesthesia after repeat celiotomy, and 26 horses (49%) were discharged from the clinic. Excluding two horses lost to follow-up, 10 of 51 horses (20%) survived long term. Horses subjected to repeat celiotomy had a significantly lower long-term survival rate than horses subjected to a single celiotomy. Twenty-eight horses had mechanical obstructions, and 22 had functional obstructions at the second surgery. Significantly more horses with mechanical obstructions recovered from anesthesia, but there was no difference in short-term or long-term survival. Seventy-seven percent of horses were subjected to two celiotomies without being discharged from the clinic between procedures. The intervals between primary and repeat celiotomies ranged from less than 24 hours to 4 years, with 89% of them being less than 2 months. Horses with functional obstructions at the second surgery had a significantly shorter interval between surgeries than horses with mechanical obstructions. Twenty-three horses had sequelae of the primary celiotomy, 19 had progression of their original disease, 8 had recurrence of the same condition, and 3 had unrelated problems. Intestinal ischemic necrosis was the most common diagnosis at repeat celiotomy, and small intestinal obstruction by adhesions was the second most frequent.     

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 resting cortisol concentration testing in dogs with chronic gastrointestinal signs

BackgroundResting cortisol concentrations are routinely measured in dogs with chronic gastrointestinal signs to rule out hypoadrenocorticism based on a concentration >2 μg/dL (>55 nmol/L).Hypothesis/ObjectivesTo assess the cross‐sectional prevalence of hypoadrenocorticism in a group of dogs with chronic gastrointestinal signs presented to a referral internal medicine service.AnimalsTwo‐hundred and eighty‐two client‐owned dogs with chronic gastrointestinal signs and with resting cortisol concentration testing performed.MethodsRetrospective review of medical records (final diagnosis, resting cortisol concentration, and adenocorticotropic hormone [ACTH] stimulation test results) of a referral population of dogs between May 2013 and September 2017.ResultsResting cortisol concentration was <2 μg/dL (<55 nmol/L) in 79 patients (28%). Repeated resting cortisol concentration measurements were performed in 28 dogs, and in 8, resting cortisol concentrations remained <2 μg/dL (<55 nmol/L). Post‐ACTH cortisol concentration was <2 μg/dL (<55 nmol/L) in 1 dog, consistent with a diagnosis of hypoadrenocorticism and giving a prevalence estimate of hypoadrenocorticism in this population of dogs of 0.3% (95% confidence interval [95CI], 0.03‐1.5%). In 19 dogs with an initial resting cortisol concentration <2 μg/dL (<55 nmol/L), hypoadrenocorticism was excluded based on a repeat resting cortisol concentration >2 μg/dL (>55 nmol/L). Overall, the most common diagnosis was chronic primary inflammatory enteropathy (176/282, 62.4%), followed by extragastrointestinal neoplasia (17/282, 6%), protein‐losing enteropathy, pancreatitis and megaesophagus (10/282, 3.5% each).Conclusions and Clinical ImportanceAlthough dogs with hypoadrenocorticism can present with chronic gastrointestinal signs, it was the final diagnosis in only 1 of 282 dogs presenting to a referral internal medicine service for signs of chronic enteropathy. Repeated resting cortisol concentration may be considered as a test to try and exclude hypoadrenocorticism.