Pharmacokinetics and clinical efficacy of cyclosporine treatment of dogs with steroid-refractory inflammatory bowel disease

Harnessing the Biology of Canine Intestinal Organoids to Heighten Understanding of Inflammatory Bowel Disease Pathogenesis and Accelerate Drug Discovery: A One Health Approach

In a recent issue of the Lancet, the prevalence of Inflammatory Bowel Disease (IBD) was estimated at 7 million worldwide. Overall, the burden of IBD is rising globally, with direct and indirect healthcare costs ranging between $14.6 and $31.6 billion in the U.S. alone in 2014. There is currently no cure for IBD, and up to 40% of patients do not respond to medical therapy. Although the exact determinants of the disease pathophysiology remain unknown, the prevailing hypothesis involves complex interplay among host genetics, the intestinal microenvironment (primarily bacteria and dietary constituents), and the mucosal immune system. Importantly, multiple chronic diseases leading to high morbidity and mortality in modern western societies, including type II diabetes, IBD and colorectal cancer, have epidemiologically been linked to the consumption of high-calorie, low-fiber, high monosaccharide, and high-fat diets (HFD). More specifically, data from our laboratory and others have shown that repeated consumption of HFD triggers dysbiotic changes of the gut microbiome concomitant with a state of chronic intestinal inflammation and increased intestinal permeability. However, progress in our understanding of the effect of dietary interventions on IBD pathogenesis has been hampered by a lack of relevant animal models. Additionally, current in vitro cell culture systems are unable to emulate the in vivo interplay between the gut microbiome and the intestinal epithelium in a realistic and translatable way. There remains, therefore, a critical need to develop translatable in vitro and in vivo models that faithfully recapitulate human gut-specific physiological functions to facilitate detailed mechanistic studies on the impact of dietary interventions on gut homeostasis. While the study of murine models has been pivotal in advancing genetic and cellular discoveries, these animal systems often lack key clinical signs and temporal pathological changes representative of IBD. Specifically, some limitations of the mouse model are associated with the use of genetic knockouts to induce immune deficiency and disease. This is vastly different from the natural course of IBD developing in immunologically competent hosts, as is the case in humans and dogs. Noteworthily, abundant literature suggests that canine and human IBD share common clinical and molecular features, such that preclinical studies in dogs with naturally occurring IBD present an opportunity to further our understanding on disease pathogenesis and streamline the development of new therapeutic strategies. Using a stepwise approach, in vitro mechanistic studies investigating the contribution of dietary interventions to chronic intestinal inflammation and "gut leakiness" could be performed in intestinal organoids and organoid derived monolayers. The biologic potential of organoids stems from the method's ability to harness hard-wired cellular programming such that the complexity of the disease background can be reflected more accurately. Likewise, the effect of therapeutic drug candidates could be evaluated in organoids prior to longitudinal studies in dog and human patients with IBD. In this review, we will discuss the value (and limitations) of intestinal organoids derived from a spontaneous animal disease model of IBD (i.e., the dog), and how it can heighten understanding of the interplay between dietary interventions, the gut microbiota and intestinal inflammation. We will also review how intestinal organoids could be used to streamline the preclinical development of therapeutic drug candidates for IBD patients and their best four-legged friends.

Cyclosporine Treatment in Cats with Presumed Chronic Pancreatitis-A Retrospective Study

Simple Summary

Chronic pancreatitis (CP) is a common disease in middle-aged to older cats. Cyclosporine, an immunosuppressive drug, has been suggested as an alternative treatment when other drugs that suppress inflammation are ineffective or unsuitable. However, no published studies have investigated its efficacy in cats with CP. The aim of this retrospective study was to evaluate the efficacy of cyclosporine as a treatment for pancreatitis in cats with presumed CP. All cats had a history and clinical signs suggestive of CP and blood samples showed abnormally high concentrations of feline pancreas-specific lipase (Spec fPL) on at least two occasions. This is common in CP. All cats were treated with cyclosporine for at least three weeks. Nineteen cats, aged 6.9–17.5 years, were included. Daily treatment with cyclosporine resulted in an improvement of serum Spec fPL concentrations which indicates that the pancreatic inflammation likely had improved. The study has several limitations, including different treatment durations and doses, lack of biopsies to confirm CP and the treatment effect was not compared with an untreated control group. Despite the limitations, our results suggest that cyclosporine treatment decreases serum Spec fPL concentrations and may be effective in the management of feline chronic pancreatitis.

Abstract

Chronic pancreatitis (CP) is a common disease in middle-aged to older cats. Cyclosporine has been suggested as an alternative treatment when other immunosuppressive treatments are insufficient or contraindicated. However, no published studies have investigated its efficacy on feline CP. The aim of this retrospective study was to evaluate the efficacy of cyclosporine on supranormal serum feline pancreas-specific lipase (Spec fPL) concentrations in cats with presumed CP. Inclusion criteria were history and clinical signs suggestive of CP, serum Spec fPL concentrations above 5.3 μg/L (reference range 0–3.5 μg/L, equivocal range 3.6–5.3 μg/L) on at least two occasions and treatment with cyclosporine for at least three weeks. Serum Spec fPL was analyzed at Idexx Laboratories, Kornwestheim, Germany. Nineteen cats, aged 6.9–17.5 years (median 11.6), were included. No pancreatic biopsies were available. Median (range) serum Spec fPL concentration was 14.2 μg/L (6.1–43.3) at baseline and 6.7 μg/L (0.9–23.6) at follow-up. Cyclosporine treatment (5.0–7.9 mg/kg orally SID) was associated with a significant reduction in serum Spec fPL concentrations (p < 0.001) at follow-up after 23–206 days (median 35). Body weight decreased significantly between inclusion and follow-up (p = 0.013). Significant improvement of clinical signs could not be measured (p = 0.781). This study has several limitations, including unstandardized treatment length and dose, no control group and lack of pancreatic biopsies. Despite the limitations, our results suggest that cyclosporine treatment reduces supranormal serum Spec fPL concentrations in cats with presumed CP.

Evaluating the use of cytosine arabinoside for treatment for recurrent canine steroid-responsive meningitis-arteritis

BACKGROUND

Relapses in steroid-responsive meningitis-arteritis (SRMA) are frequently observed but specific treatment protocols to address this problem are sparsely reported. Standard treatment includes prolonged administration of glucocorticoids as monotherapy or in combination with immunosuppressive drugs. The aim of this study was to assess the safety and efficacy of cytosine arabinoside (CA) in combination with glucocorticoids for treatment of SRMA relapses in 12 dogs on a retrospective basis.

METHODS

Dogs with recurrent episodes of SRMA and treated with a combination of CA and prednisolone were included. Information about clinical course, treatment response and adverse events was collected from medical records. Ethical approval was not required for this study.

RESULTS

Ten dogs (10/12) responded well to the treatment with clinical signs being completely controlled. One dog is in clinical remission, but still under treatment. One dog (8%) showed further relapse. Mean treatment period was 51 weeks. Adverse events of variable severity (grade 1-4/5) were documented in all dogs during treatment according to the veterinary cooperative oncology group grading. Three dogs developed severe adverse events. Laboratory findings showed marked changes up to grade 4. Diarrhoea and anaemia were the most often observed adverse events (6), followed by dermatitis (4), alopecia (3) and pneumonia (3). Including blood chemistry changes (13), 50 adverse events were found in total.

CONCLUSION

Treatment with CA and glucocorticoids resulted in clinical remission in 10/12 dogs, but a high incidence of adverse events occurred requiring additional measures. All adverse events could be managed successfully in all cases.

Ki-67/CD3 ratio in the diagnosis of chronic inflammatory enteropathy in dogs

BACKGROUND

T cells play a key role in the pathogenesis of chronic inflammatory enteropathy (CIE) in dogs. Cluster of differentiation 3 (CD3) antigen serves as a marker for T cells. In human medicine, Ki-67 is an indicator for cell growth but there are only a few studies in dogs with CIE.

OBJECTIVE

To investigate Ki-67 in relation to T cells as a marker for CIE in dogs.

ANIMALS

Eleven dogs with CIE and 6 healthy beagle controls (CO).

METHODS

Retrospective case-control study. Dogs were clinically assessed by the Canine Chronic Enteropathy Clinical Activity Index (CCECAI). Duodenal mucosal biopsy samples were endoscopically obtained for histopathologic examination by means of the World Small Animal Veterinary Association score. Double-labeled immunofluorescence was used to investigate colocalization of Ki-67 and CD3 in epithelium and lamina propria (LP) of villi and crypts.

RESULTS

Dogs with CIE had significantly higher clinical score (median, 5.0; interquartile range [IQR], 3-7) compared to CO (all 0; P < .001). The Ki-67/CD3 double-positive cells were significantly increased in the LP of the crypt region of CIE dogs (0.63 cells/mm² ; IQR, 0-0.54) versus CO (0.08 cells/mm² ; IQR, 0-0.26; P = .044). A significant correlation was found between CCECAI and the Ki-67/CD3 ratio in the LP of the crypt region (r = 0.670; P = .012) in dogs with CIE.

CONCLUSIONS AND CLINICAL IMPORTANCE

The Ki-67/CD3 ratio is upregulated in the LP crypt region of dogs with CIE and it correlates with clinical severity. Therefore, Ki-67/CD3 could be a useful tool for detection of CIE.

Retrospective evaluation of cyclosporine in the treatment of presumed idiopathic chronic hepatitis in dogs

Background

The etiology of idiopathic chronic hepatitis (ICH) in dogs is poorly understood, but evidence supports an immune‐mediated pathogenesis in some dogs.

Objectives

To describe a case series of dogs with presumed ICH treated with cyclosporine (CsA) with or without concurrent medications and to document the incidence of biochemical remission and factors associated with failure to attain remission.

Animals

Forty‐eight client‐owned dogs diagnosed with presumed ICH, treatment of which included CsA.

Methods

Two‐institution, retrospective case series of dogs between 2010 and 2017. All dogs were treated with CsA with or without concurrent medications for ≥2 weeks. Data were collected from medical records.

Results

Biochemical remission (<1.1 times the upper limit of normal for alanine aminotransferase activity) was attained in 79% of dogs (38/48). Median dose of CsA at remission was 7.9 mg/kg/d (range, 2.5‐12.7 mg/kg/d) and median time to remission was 2.5 months (range, 0.75‐18 months). Concurrent hepatoprotectant treatment was not associated with likelihood of remission. Clinical score, ascites, hypoalbuminemia, hyperbilirubinemia, prolonged coagulation times, dose, and duration of treatment were not associated with the probability of remission or time to remission. Common adverse effects of CsA were gastrointestinal signs in 38% (18/48) and gingival hyperplasia in 25% (12/48) of treated dogs.

Conclusion and Clinical Importance

A treatment regimen including CsA and frequent hepatoprotectant use resulted in biochemical remission of ICH in most dogs. None of the evaluated factors, including hepatoprotectant use, were significantly associated with likelihood of remission. Future prospective studies are indicated to evaluate CsA monotherapy in ICH dogs.

Canine adipose tissue-derived mesenchymal stem cells pre-treated with TNF-alpha enhance immunomodulatory effects in inflammatory bowel disease in mice

Canine inflammatory bowel disease (IBD) is an intractable autoimmune disorder that results in various gastrointestinal and systemic symptoms. Mesenchymal stem cells (MSCs), which release immunomodulatory factors such as tumor necrosis factor-α (TNF-α)-induced gene/protein 6 (TSG-6) and prostaglandin E2 (PGE2), have been suggested as an alternative therapeutic option for IBD treatment in veterinary medicine. Furthermore, although it is known that MSCs pre-treated with pro-inflammatory cytokines show enhanced anti-inflammatory properties via the secretion of soluble factors, the underlying mechanisms of IBD remain unclear. The aim of this study was to demonstrate the therapeutic effects and corresponding mechanisms of canine adipose tissue-derived (cAT)-MSCs stimulated with TNF-α in mouse models of IBD. Mice with dextran sulfate sodium (DSS)- or dinitrobenzene sulfonic acid (DNBS)-induced colitis were injected intraperitoneally with cAT-MSCs pre-treated with TNF-α. Colitis severity was assessed and colon tissues were collected for histopathological, enzyme-linked immunosorbent assay, and flow cytometry analysis. cAT-MSCs stimulated with TNF-α secreted higher concentrations of immunomodulatory factors such as TSG-6 and PGE2, which play a key role in inducing phenotypic alterations in macrophages. Consequently, TNF-α-pre-treated cAT-MSCs further regulated colonic inflammatory cytokines such as interleukin (IL)-1β, IL-6, and IL-10, and ameliorated DSS- or DNBS-induced colitis in mice. Additionally, we demonstrated that M1 macrophages (F4/80⁺/iNOS⁺ cells) were decreased in colon tissues from mice treated with TNF-α-pre-treated cAT-MSCs, whereas M2 macrophages (F4/80⁺/CD206⁺ cells) were increased. These results may suggest a new cell-based therapeutic option for treating IBD.

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Canine AT-MSCs stimulated with TNF-α enhanced immunomodulatory factor secretion.

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TNF-α-stimulated cAT-MSCs showed enhanced anti-inflammatory effects during experimental colitis.

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TNF-α-stimulated cAT-MSCs induced M2 macrophage phenotypic alterations in the colon.

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Preconditioning canine AT-MSCs with TNF-α could be applicable to dogs with IBD.

Interleukin-13 and interleukin-33 mRNA are underexpressed in the duodenal mucosa of German Shepherd dogs with chronic enteropathy

BACKGROUND

A recent genome-wide association study in German Shepherd dogs (GSDs) with chronic enteropathy (CE) has identified polymorphisms in the Th2 cytokine genes.

HYPOTHESIS/OBJECTIVE

To determine if the expression of the Th2 cytokines, interleukin-13 (IL-13) and interleukin-33 (IL-33), is altered in the duodenal mucosa of GSDs with CE compared to non-GSDs with CE and healthy dogs.

ANIMALS

Twenty client-owned dogs diagnosed with CE (10 GSDs and 10 non-GSDs) at the Bristol Veterinary School and 8 healthy Beagle dogs from the Iowa State University Service Colony.

METHODS

Retrospective study using archived paraffin-embedded duodenal biopsy samples. A novel RNA in situ hybridization technology (RNAscope) was used to hybridize IL-13 and IL-33 mRNA probes onto at least 10 sections from duodenal biopsy samples for each dog. RNAscope signals were visualized using a microscope and semi-quantitative assessment was performed by a single operator.

RESULTS

Based on duodenal villus, subvillus, epithelial, and lamina propria average expression scores, GSDs with CE had significantly lower IL-13 and IL-33 mRNA expression compared to non-GSDs with CE (IL-13, P < .04; IL-33, P < .02) and healthy Beagle dogs (IL-13, P < .02; IL-33, P < .004).

CONCLUSIONS AND CLINICAL IMPORTANCE

Similar to human patients with ulcerative colitis, a subtype of human inflammatory bowel disease, these data indicate that Th2 cytokines may be involved in the pathogenesis of CE in GSDs.

Narrative review of therapies for chronic enteropathies in dogs and cats

BACKGROUND

The optimal medical treatment for chronic enteropathy (CE) in dogs and cats is controversial. Sequential treatment using diet, antimicrobials, and immunosuppressive drugs is the most common strategy used by clinicians.

OBJECTIVES

To review the evidence for the effectiveness of dietary, drug, and alternative health interventions for inducing clinical remission in dogs and cats with CE.

ANIMALS

Retrospective study of dogs and cats with a diagnosis of chronic enteropathy.

METHODS

MEDLINE and Centre for Agriculture and Bioscience International (CABI) databases (1950 to March 2017) were searched for randomized controlled trials (RCTs), observational studies, and case series. The primary outcome was induction of clinical remission. All studies were evaluated using the quality of evidence grading guidelines (I-IV), which assign a score defining the strength and quality of the evidence.

RESULTS

Twenty-two studies (11 RCTs in dogs and 2 in cats and 9 cohort studies or case series) met the inclusion criteria for inducing remission of gastrointestinal (GI) signs. Of the 13 RCTs achieving grade I scores, 10 studies (totaling 218 dogs and 65 cats) compared single treatment: diet (n = 3), immunosuppressives (n = 3), antimicrobials (n = 2), anti-inflammatory drugs (n = 1), and probiotics (n = 1). Three case series (grade III) reported clinical remission using an elimination diet fed to 55 cats and use of enrofloxacin to induce remission in dogs with granulomatous colitis (2 studies totaling 16 dogs).

CONCLUSIONS AND CLINICAL IMPORTANCE

The current evidence for treatment of CE is much greater in dogs than in cats. There is sufficient strong evidence to recommend the use of therapeutic GI diets, glucocorticoids, enrofloxacin, or some combination of these in dogs with CE. Therapeutic GI diets and glucocorticoids are most useful in cats with CE.

Genome-wide association studies of inflammatory bowel disease in German shepherd dogs

Canine Inflammatory Bowel Disease (IBD) is considered a multifactorial disease caused by complex interactions between the intestinal immune system, intestinal microbiota and environmental factors in genetically susceptible individuals. Although IBD can affect any breed, German shepherd dogs (GSD) in the UK are at increased risk of developing the disease. Based on previous evidence, the aim of the present study was to identify single nucleotide polymorphisms (SNPs), which may confer genetic susceptibility or resistance to IBD using a genome-wide association study (GWAS). Genomic DNA was extracted from EDTA blood or saliva samples of 96 cases and 98 controls. Genotyping of cases and controls was performed on the Canine Illumina HD SNP array and data generated was analyzed using PLINK. Several SNPs and regions on chromosomes 7,9,11 and 13 were detected to be associated with IBD using different SNP-by-SNP association methods and FST windows approach. Searching one Mb up-and down-stream of the most significant SNPs, as identified by single SNP analysis as well as 200Kb before and after the start and the end position of the associated regions identified by FST windows approach, we identified 63 genes. Using a combination of pathways analysis and a list of genes that have been reported to be involved in human IBD, we identified 16 candidate genes potentially associated with IBD in GSD.

Intestinal Stem Cells to Advance Drug Development, Precision, and Regenerative Medicine: A Paradigm Shift in Translational Research

Recent advances in our understanding of the intestinal stem cell niche and the role of key signaling pathways on cell growth and maintenance have allowed the development of fully differentiated epithelial cells in 3D organoids. Stem cell-derived organoids carry significant levels of proteins that are natively expressed in the gut and have important roles in drug transport and metabolism. They are, therefore, particularly relevant to study the gastrointestinal (GI) absorption of oral medications. In addition, organoids have the potential to serve as a robust preclinical model for demonstrating the effectiveness of new drugs more rapidly, with more certainty, and at lower costs compared with live animal studies. Importantly, because they are derived from individuals with different genotypes, environmental risk factors and drug sensitivity profiles, organoids are a highly relevant screening system for personalized therapy in both human and veterinary medicine. Lastly, and in the context of patient-specific congenital diseases, orthotopic transplantation of engineered organoids could repair and/or replace damaged epithelial tissues reported in various GI diseases, such as inflammatory bowel disease, cystic fibrosis, and tuft enteropathy. Ongoing translational research on organoids derived from dogs with naturally occurring digestive disorders has the potential to improve the predictability of preclinical models used for optimizing the therapeutic management of severe chronic enteropathies in human patients.

Evaluation of Serum 3-Bromotyrosine Concentrations in Dogs with Steroid-Responsive Diarrhea and Food-Responsive Diarrhea

Background

The clinical usefulness of serum 3‐BrY concentrations for subclassifying dogs with food‐responsive diarrhea (FRD) and steroid‐responsive diarrhea (SRD) has not been studied.

Hypothesis/Objectives

To compare serum 3‐BrY concentrations in dogs with FRD, dogs with SRD, and healthy control dogs.

Animals

38 dogs with FRD, 14 dogs with SRD, and 46 healthy dogs.

Methods

Prospective study. Measurement of 3‐BrY concentration in serum samples was performed by gas chromatography/mass spectrometry.

Results

There was no association of peripheral eosinophilia in dogs with FRD, SRD, and healthy control dogs (P = 0.069). There was no significant correlation between peripheral eosinophil counts and serum 3‐BrY concentrations (ρ = −0.15, P = 0.13). Serum 3‐BrY concentrations in dogs with SRD (median [range] = 3.27, 0.9–26.23 μmol/L) were significantly higher than in dogs with FRD (median [range] = 0.99, 0.62–8.82 μmol/L; P = 0.007) or in healthy dogs (median [range] = 0.62, 0.62–1.79 μmol/L; P < 0.001). Also, serum 3‐BrY concentrations in dogs with FRD were significantly higher than in healthy dogs (P = 0.025). There was no significant correlation between the canine chronic enteropathy clinical activity index and serum 3‐BrY concentrations (ρ = 0.17, P = 0.23).

Conclusions and Clinical Importance

Measurement of serum 3‐BrY concentrations, but not the peripheral eosinophil count, is helpful for detecting dogs with SRD and FRD.

Hypovitaminosis D is associated with negative outcome in dogs with protein losing enteropathy: a retrospective study of 43 cases

Background

Hypovitaminosis D has previously been shown to be prevalent amongst dogs with protein losing enteropathy (PLE).

The hypothesis of this study was that Low 25-hydroxyvitamin D (25(OH) D) serum concentrations could be a risk factor for negative outcome in dogs with PLE.

Forty-three dogs diagnosed with PLE (2005–2014) and which serum Vitamin D serum concentrations were collected and archived at −80 Degrees C were analyzed.

Post-diagnostic communication with referring veterinarians was made to determine outcome of PLE dogss: Dogs which died due to PLE within 4 months after diagnosis (negative outcome group, n = 22) and dogs alive or which died due to another disease at the end point of the study (1 year after diagnosis, good outcome group, n = 21). Serum samples taken at the time of diagnosis were analysed for ionized calcium (iCa) concentrations and serum 25(OH) D concentration.

Results

Clinical (CCECAI) scores, age at PLE diagnosis, and iCa concentrations were not significantly different between dog groups. A significantly greater (p < 0.001) number of PLE dogs treated with hydrolyzed or elimination diet alone showed good outcome as compared to the PLE negative outcome group. Median serum 25(OH) D concentration was significantly (p = 0.017) lower in dogs with negative outcome versus PLE dogs with good outcome. Using logistic regression analysis, 25(OH) D serum concentration was shown to be a statistically significant factor for outcome determination. Cox regression analysis yielded a hazard ratio of 0.974 (95% CI 0.949, 0.999) per each one nmol/l increase in serum 25(OH) D concentration.

Conclusions

Low serum 25(OH) D concentration in PLE dogs was significantly associated with poor outcome. Further studies are required to investigate the clinical efficacy of Vitamin D (cholecalciferol) as a potential therapeutic agent for dogs with PLE.

Oral chondroitin sulfate and prebiotics for the treatment of canine Inflammatory Bowel Disease: a randomized, controlled clinical trial

Background

Canine inflammatory bowel disease (IBD) is a chronic enteropathy of unknown etiology, although microbiome dysbiosis, genetic susceptibility, and dietary and/or environmental factors are hypothesized to be involved in its pathogenesis. Since some of the current therapies are associated with severe side effects, novel therapeutic modalities are needed. A new oral supplement for long-term management of canine IBD containing chondroitin sulfate (CS) and prebiotics (resistant starch, β-glucans and mannaoligosaccharides) was developed to target intestinal inflammation and oxidative stress, and restore normobiosis, without exhibiting any side effects. This double-blinded, randomized, placebo-controlled trial in dogs with IBD aims to evaluate the effects of 180 days administration of this supplement together with a hydrolyzed diet on clinical signs, intestinal histology, gut microbiota, and serum biomarkers of inflammation and oxidative stress.

Results

Twenty-seven client-owned biopsy-confirmed IBD dogs were included in the study, switched to the same hydrolyzed diet and classified into one of two groups: supplement and placebo. Initially, there were no significant differences between groups (p > 0.05) for any of the studied parameters. Final data analysis (supplement: n = 9; placebo: n = 10) showed a significant decrease in canine IBD activity index (CIBDAI) score in both groups after treatment (p < 0.001). After treatment, a significant decrease (1.53-fold; p < 0.01) in histologic score was seen only in the supplement group. When groups were compared, the supplement group showed significantly higher serum cholesterol (p < 0.05) and paraoxonase-1 (PON1) levels after 60 days of treatment (p < 0.01), and the placebo group showed significantly reduced serum total antioxidant capacity (TAC) levels after 120 days (p < 0.05). No significant differences were found between groups at any time point for CIBDAI, WSAVA histologic score and fecal microbiota evaluated by PCR-restriction fragment length polymorphism (PCR-RFLP). No side effects were reported in any group.

Conclusions

The combined administration of the supplement with hydrolyzed diet over 180 days was safe and induced improvements in selected serum biomarkers, possibly suggesting a reduction in disease activity. This study was likely underpowered, therefore larger studies are warranted in order to demonstrate a supplemental effect to dietary treatment of this supplement on intestinal histology and CIBDAI.

Phenotypic characterization of canine intestinal intraepithelial lymphocytes in dogs with inflammatory bowel disease

Background

Many dogs suffering from inflammatory bowel disease (IBD) are presented to veterinary clinics. These patients are diagnosed based on a history of chronic gastrointestinal signs and biopsy‐confirmed histopathologic intestinal inflammation. Intestinal intraepithelial lymphocytes (IEL) are part of the first line of defense in the gastrointestinal immune system. Alterations in IEL subsets may play a role in the pathogenesis of IBD.

Hypothesis

The aim of this study was to characterize the phenotypes of IEL in dogs with IBD compared with healthy control dogs.

Animals

Intestinal intraepithelial lymphocytes subpopulations of control dogs (n = 5) obtained from endoscopic biopsies (EB) were compared to those obtained from full thickness biopsies (FTB) on the same day. In addition, the phenotypes of IEL from FTB of control dogs (n = 10) were compared with EB of IBD dogs (n = 10). Each participant was scored clinically using the canine inflammatory bowel disease activity index (CIBDAI), and all samples were graded histopathologically. Three‐color flow cytometry of isolated IEL was performed using monoclonal antibodies against T‐ and B‐lymphocyte subpopulations.

Results

No significant differences in the composition of IEL subpopulations were found in control dogs based on method of biopsy. The IBD dogs had significantly higher CIBDAI and histopathologic scores compared with control dogs and their IEL contained a significantly higher frequency TCRγδ T‐cells.

Conclusions and Clinical Importance

Endoscopic biopsies provide suitable samples for 3‐color flow cytometry when studying canine intestinal IEL and IBD patients show significant changes of major T‐cell subsets compared to healthy control dogs.

Analytical validation of a quantitative reverse transcriptase polymerase chain reaction assay for evaluation of T-cell targeted immunosuppressive therapy in the dog

Cyclosporine is an immunosuppressive agent that inhibits T-cell function by decreasing production of cytokines such as interleukin-2 (IL-2) and interferon-γ(IFN-γ). In dogs, there is currently no reliable analytical method for determining effective cyclosporine dosages in individual patients. Our laboratory has developed a quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) assay that measures IL-2 and IFN-γ gene expression, with the goal of quantifying immunosuppression in dogs treated with cyclosporine. This study focuses on analytical validation of our assay, and on the effects of sample storage conditions on cyclosporine-exposed samples. Heparinized whole blood collected from healthy adult dogs was exposed to a typical post-treatment blood concentration for cyclosporine(500 ng/mL) for 1 h, and then stored for 0, 24, and 48 h at both room temperature and 4 ◦C.The study was then repeated using a cyclosporine concentration of 75 ng/mL, with sample storage for 0, 24, and 48 h at 4 ◦C. Cytokine gene expression was measured using RT-qPCR,and assay efficiency and inter- and intra-assay variability were determined. Storage for upto 24 h at room temperature, and up to 48 h at 4 ◦C, did not significantly alter results compared to samples that were processed immediately. Validation studies showed our assay to be highly efficient and reproducible and robust enough to be feasible under standard practice submission conditions.

The clinical efficacy of dietary fat restriction in treatment of dogs with intestinal lymphangiectasia

BACKGROUND

Intestinal lymphangiectasia (IL), a type of protein-losing enteropathy (PLE), is a dilatation of lymphatic vessels within the gastrointestinal tract. Dietary fat restriction previously has been proposed as an effective treatment for dogs with PLE, but limited objective clinical data are available on the efficacy of this treatment.

HYPOTHESIS/OBJECTIVES

To investigate the clinical efficacy of dietary fat restriction in dogs with IL that were unresponsive to prednisolone treatment or showed relapse of clinical signs and hypoalbuminemia when the prednisolone dosage was decreased.

ANIMALS

Twenty-four dogs with IL.

METHODS

Retrospective study. Body weight, clinical activity score, and hematologic and biochemical variables were compared before and 1 and 2 months after treatment. Furthermore, the data were compared between the group fed only an ultra low-fat (ULF) diet and the group fed ULF and a low-fat (LF) diet.

RESULTS

Nineteen of 24 (79%) dogs responded satisfactorily to dietary fat restriction, and the prednisolone dosage could be decreased. Clinical activity score was significantly decreased after dietary treatment compared with before treatment. In addition, albumin (ALB), total protein (TP), and blood urea nitrogen (BUN) concentration were significantly increased after dietary fat restriction. At 2 months posttreatment, the ALB concentrations in the ULF group were significantly higher than that of the ULF + LF group.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dietary fat restriction appears to be an effective treatment in dogs with IL that are unresponsive to prednisolone treatment or that have recurrent clinical signs and hypoalbuminemia when the dosage of prednisolone is decreased.

Oral cyclosporine treatment in dogs: a review of the literature

Cyclosporine is an immunomodulatory drug used to treat an increasing spectrum of diseases in dogs. Cyclosporine is a calcineurin inhibitor, ultimately exerting its inhibitory effects on T-lymphocytes by decreasing production of cytokines, such as interleukin-2. Although, in the United States, oral cyclosporine is approved in dogs only for treatment of atopic dermatitis, there are many other indications for its use. Cyclosporine is available in 2 oral formulations: the original oil-based formulation and the more commonly used ultramicronized emulsion that facilitates oral absorption. Ultramicronized cyclosporine is available as an approved animal product, and human proprietary and generic preparations are also available. Bioavailability of the different formulations in dogs is likely to vary among the preparations. Cyclosporine is associated with a large number of drug interactions that can also influence blood cyclosporine concentrations. Therapeutic drug monitoring (TDM) can be used to assist in attaining consistent plasma cyclosporine concentrations despite the effects of varying bioavailability and drug interactions. TDM can facilitate therapeutic success by guiding dose adjustments on an individualized basis, and is recommended in cases that do not respond to initial oral dosing, or during treatment of severe, life-threatening diseases for which a trial-and-error approach to dose adjustment is too risky. Pharmacodynamic assays that evaluate individual patient immune responses to cyclosporine can be used to augment information provided by TDM.

Cyclosporin a inhibits rotavirus replication and restores interferon-beta signaling pathway in vitro and in vivo

Rotavirus (RV) is the most common cause of severe diarrhea among infants and young children. Currently, there is no specific drug available against rotavirus, largely due to the lack of an ideal target molecule which has hampered drug development. Our previous studies have revealed that cyclosporin A (CsA) might be potentially useful as an anti-RV drug. We therefore used both cellular and mouse models to study the immunological safety and effectiveness of CsA as an anti-RV drug. We found that CsA treatment of HT-29 cells before, during, and after viral infection efficiently inhibited Wa strain RV replication and restored IFN-β expression in a HT-29 cell line model. Exploring the underlying mechanisms showed that CsA promoted Interferon Regulatory Factor-5 (IRF-5) expression (a key positive regulator of the type I IFN signaling pathway), but not IRF-1, IRF-3, or IRF-7. Additionally, CsA inhibited SOCS-1 expression (the key negative regulator of IFN-α/β), but not SOCS-2 or SOCS-3. The antiviral effect of CsA was confirmed in an RV-infected neonatal mouse model by evaluation of antigen clearance and assessment of changes in intestinal tissue pathology. Also, no differences in T cell frequency or proliferation between the CsA- and vehicle-treated groups were observed. Thus, both our in vitro and in vivo findings suggest that CsA, through modulating the expression of key regulators in IFN signaling pathway, promote type I IFN-based intracellular innate immunity in RV host cells. These findings suggest that CsA may be a useful candidate to develop a new anti-RV strategy, although further evaluation and characterization of CsA on RV-induced diarrhea are warranted.

Unsuccessful cyclosporine plus prednisolone therapy for autoimmune meningoencephalitis in three dogs

A 4-year-old female Maltese (case 1), a 9-year-old castrated male shih tzu (case 2) and 2-year-old female Pomeranian (case 3) presented with neurological signs, such as head tilt, ataxia, circling and paresis. The three cases were tentatively diagnosed as having meningoencephalitis of unknown etiology based on computed tomography scan and cerebrospinal fluid analysis. All patients were managed with cyclosporine plus prednisolone therapy. The survival times of the three patients were 170, 70 and 21 days, respectively. After the cases died, we performed necropsy and histopathological examination for definitive diagnosis. Based on the necropsy, histopathological and immunohistochemical examinations, cases 1, 2 and 3 were definitely diagnosed as having necrotizing meningoencephalitis, necrotizing leukoencephalitis and granulomatous meningoencephalitis, respectively. This case report demonstrated the clinical findings, brain CT characteristics and histopathological and immunohistochemical features of NME, NLE and GME in dogs and discussed the reason for the relatively short survival times under cyclosporine plus prednisolone therapy.

Diagnosis of small intestinal disorders in dogs and cats

Laboratory tests are an important part of the workup of small intestinal diseases in dogs and cats. Especially in chronic cases, when extragastrointestinal causes need to be ruled out, it is important to adhere to a systematic workup. This article details the newest available data on tests to aid this diagnostic process. Once the diagnosis of a chronic enteropathy is made, there are many laboratory tests that can help in monitoring the disease and providing prognostic information. Several new tests being evaluated for clinical usefulness are discussed.

The characteristics of short- and long-term surviving Shiba dogs with chronic enteropathies and the risk factors for poor outcome

Background

The objectives of this study were to investigate the differences in the characteristics of short- and long-term surviving dogs, and the factors that predict poor outcome in Shiba dogs with chronic enteropathies (CE).

Methods

A total of 25 Shiba dogs were included in this study, and classified as either short-term (≤6 months) survivors (Ss; n=16) or long-term (>6 months) survivors (Ls; n=9). The clinical and clinicopathological variables, histopathology, response to therapy, and outcomes were investigated between groups. Furthermore, these factors were tested for their ability to predict poor outcome.

Results

All CE dogs were diagnosed as having inflammatory bowel disease (IBD) with lymphocytic-plasmacytic enteritis (LPE). Age and canine inflammatory bowel disease activity index (CIBDAI) were significantly higher in the Ss group than in the Ls group (age: p = 0.035, CIBDAI: p = 0.018), as determined via univariate logistic regression analysis. According to receiver operator characteristic (ROC) curve analysis, the best predictors of poor outcome were age and CIBDAI, with the cutoffs determined as 7 years and 9 points, respectively. The majority of the cases (84%) responded to initial treatment; in particular, 75% of dogs in Ss group responded to therapy. The time to response (days) to the initial treatment in the Ss group (median 42.5 days, range: 20-91 days) was significantly shorter than that of the Ls group (median 285 days, range: 196-1026 days). Approximately half (55.5%) of the dogs in the Ls group died due to relapse of CE.

Conclusions

This study suggested that there is a high risk of early mortality in Shiba dogs with CE, particularly if the dogs are older (>7 years) and have a high CIBDAI score (>9 points). There appears to be a possibility of early mortality even if the initial treatment was efficacious. Furthermore, Shiba dogs with CE that become less responsive to initial therapy in the short-term (approximately 3 months) are more likely to have an early mortality. Thus, it is necessary to follow-up Shiba dogs with CE in the long-term, as approximately half of the long-term survivors eventually died due to a relapse of the signs.

Management of a Dog with Poorly Regulated Diabetes Mellitus, Chronic Pancreatitis, and Suspected Atopy with Cyclosporine

A 3-year-and-9-months old male neutered Bichon Frise was presented for a second opinion for diabetes mellitus, weight loss, pruritus, and loss of hair. During further work-up, the dog was diagnosed with uncontrolled diabetes mellitus and concurrent diagnoses of pancreatitis and atopy were also suspected. Multiple adjustments of insulin therapy did not improve control of diabetes mellitus. Also, a variety of different treatments failed to improve pruritus. The dog was seen by a veterinary dermatologist who further suspected atopy and started treatment with cyclosporine. Pruritus improved and coincidentally serum Spec cPL and fructosamine concentrations normalized after therapy, suggesting the possibility that cyclosporine may have controlled pancreatic inflammation and improved control of diabetes mellitus. This case report would suggest that further research into autoimmunity in dogs with chronic pancreatitis is warranted. Also, a controlled study is needed and in progress before the use of cyclosporine in dogs with chronic pancreatitis or a subgroup thereof can be advocated.