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Schwertner K, Gelles K, Leitner J, Steinberger P, Gundacker C, Vrticka R, Hoffmann-Sommergruber K, Ellinger I, Geiselhart S. Human intestine and placenta exhibit tissue-specific expression of RAGE isoforms. Heliyon 2023; 9:e18247. [PMID: 37533998 PMCID: PMC10391957 DOI: 10.1016/j.heliyon.2023.e18247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 08/04/2023] Open
Abstract
The receptor for advanced glycation end products (RAGE) is encoded by AGER, a gene that is subjected to tissue-specific alternative splicing. Splice variants of RAGE in intestine and placenta are unknown and contradictory data concerning RAGE protein expression in these tissues have been published. As a basis for future functional studies, we examined RAGE expression in small intestine, colon and placentas. PCR cloning revealed that full-length RAGE is the only RAGE transcript isoform expressed in placenta. In the small intestine, the major transcript isoform detected was RAGE_v1 encoding the C-terminally truncated soluble receptor. In the colon, both full-length RAGE as well as several splice variants were identified. Four antibodies were used to study protein expression by immunoblotting and were carefully validated. Appropriate controls were essential to avoid misinterpretation of bands caused by non-specific reactivity of antibodies. Only one of four antibodies tested detected full-length RAGE in placenta, whereas no RAGE-specific band was detected in intestinal tissues despite loading >30-fold more intestinal tissue than the positive control, human lung. RAGE expression levels in the placenta were 100-fold lower compared with human lung when analyzed by ELISA, and no significant differences in RAGE expression were detected between healthy placentas and placentas from women with preeclampsia, gestational diabetes mellitus, or fetal growth restriction. We conclude that healthy placental chorionic tissue expresses low levels of full-length RAGE, whereas expression of the tissue-specific intestinal isoforms is below the limit of detection. Low RAGE expression levels in combination with a lack of antibody validation may explain the conflicting published results on RAGE protein expression in intestine and placenta.
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Affiliation(s)
- Katharina Schwertner
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Katharina Gelles
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Judith Leitner
- Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Peter Steinberger
- Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Claudia Gundacker
- Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Ruben Vrticka
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | | | - Isabella Ellinger
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Sabine Geiselhart
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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Ullal TV, Marks SL, Huebner SN, Taylor SL, Shelley CD. Association of folate concentrations with clinical signs and laboratory markers of chronic enteropathy in dogs. J Vet Intern Med 2023; 37:455-464. [PMID: 36919188 DOI: 10.1111/jvim.16681] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 02/24/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Serum folate is considered a biomarker of chronic enteropathy (CE) in dogs, but few studies have examined associations with markers of CE. HYPOTHESIS/OBJECTIVES To evaluate serum folate concentrations in dogs with and without CE and associations with sample hemolysis and selected markers of CE. We hypothesized that hypofolatemia would be more common in dogs with CE and associated with hypocobalaminemia, higher CIBDAI, and hypoalbuminemia. ANIMALS Six hundred seventy-three dogs with available serum folate measurements performed at an academic veterinary hospital between January 2016 and December 2019. METHODS Medical records were retrospectively reviewed to categorize cases as CE or non-CE and record clinical details and laboratory markers. Relationships between serum folate, cobalamin, and CE variables were assessed using chi-square, Kruskal-Wallis, or Spearman's correlation tests. RESULTS Of the 673 dogs, 99 CE were compared to 95 non-CE. In the overall cohort, serum folate concentration did not correlate with sample hemolysis (P = .75). In the CE subset, serum folate and cobalamin concentrations were positively associated (rho = 0.34, FDR = 0.02). However, serum folate concentrations (median [25th, 75th percentiles]) were higher (CE: 12.1 (8.9, 16.1), non-CE: 10.4 (7.2, 15.5); P = .04) and cobalamin concentrations were lower (CE: 343 (240, 597), non-CE: 550 (329, 749); P = .001) in the CE vs non-CE group. Serum folate was not associated with markers of CE, but serum cobalamin was associated with albumin (P = .04) and cholesterol (P = .03). CONCLUSIONS AND CLINICAL IMPORTANCE Hypofolatemia is an inferior biomarker of CE compared to hypocobalaminemia.
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Affiliation(s)
- Tarini V Ullal
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Stanley L Marks
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Sara N Huebner
- School of Veterinary Medicine, University of California Davis, Davis, California, USA
| | - Sandra L Taylor
- Division of Biostatistics, School of Medicine, University of California, Sacramento, California, USA
| | - Courtney D Shelley
- Division of Biostatistics, School of Medicine, University of California, Sacramento, California, USA
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3
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Langlois DK, Pritchard JC, Tolbert MK, Jergens AE, Block G, Hanzlicek AS, Jaffey JA, Steiner JM, Marsilio S, Jablonski SA. Clinical utility of an immunoglobulin A-based serological panel for the diagnosis of chronic enteropathy in dogs. Vet Med (Auckl) 2023; 37:446-454. [PMID: 36708202 DOI: 10.1111/jvim.16636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/06/2023] [Indexed: 01/29/2023]
Abstract
BACKGROUND A panel of IgA-based serologic assays might aid in the diagnosis of chronic enteropathy (CE) in dogs, a syndrome encompassing conditions such as food-responsive enteropathy, immunosuppressant-responsive enteropathy, and inflammatory bowel disease (also referred to as chronic inflammatory enteropathy). However, it is unclear whether these biomarkers discriminate between CE and other types of primary intestinal disorders. OBJECTIVES To evaluate a diagnostic panel that measures serum concentrations of IgA directed against OmpC (ACA), canine calprotectin (ACNA), and gliadin-derived peptides (AGA) in dogs with well-characterized intestinal diseases. ANIMALS Fifty-five dogs with primary intestinal disease. METHODS Serum ACA, ACNA, and AGA concentrations were measured in 30 dogs with CE and 25 dogs with other intestinal diseases (non-CE population), including histoplasmosis, parasitism, E. coli-associated granulomatous colitis, and lymphoma. Serum IgA concentrations were compared among populations, and sensitivities and specificities were calculated using laboratory-provided cut-points. RESULTS Twenty-six of 30 (87%) CE dogs and 21 of 25 (84%) non-CE dogs had abnormal concentrations (intermediate or high) of at least 2 markers; these proportions were not significantly different (P = .99). A serum ACA concentration ≥15 EU/mL was 86.7% (95% confidence interval [CI], 69.3%-96.2%) sensitive and 24.0% (95% CI, 9.4%-45.1%) specific for CE diagnosis. High AGA concentrations were observed in 16 of 25 (64%) non-CE dogs. CONCLUSIONS AND CLINICAL IMPORTANCE The evaluated serologic markers were poorly specific for CE diagnosis, which raises concerns that their use in clinical practice might lead to misdiagnoses and delayed or even detrimental treatments in dogs with non-CE intestinal diseases.
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Affiliation(s)
- Daniel K Langlois
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Jessica C Pritchard
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - M Katherine Tolbert
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Albert E Jergens
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Gary Block
- Ocean State Veterinary Specialists, East Greenwich, Rhode Island, USA
| | | | - Jared A Jaffey
- Department of Specialty Medicine, College of Veterinary Medicine, Midwestern University, Glendale, Arizona, USA
| | - Jörg M Steiner
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Sina Marsilio
- Department of Medicine and Epidemiology, University of California, Davis, California, USA
| | - Sara A Jablonski
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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Abstract
Over the last decade, chronic inflammatory enteropathies (CIE) in dogs have received great attention in the basic and clinical research arena. The 2010 ACVIM Consensus Statement, including guidelines for the diagnostic criteria for canine and feline CIE, was an important milestone to a more standardized approach to patients suspected of a CIE diagnosis. Great strides have been made since understanding the pathogenesis and classification of CIE in dogs, and novel diagnostic and treatment options have evolved. New concepts in the microbiome-host-interaction, metabolic pathways, crosstalk within the mucosal immune system, and extension to the gut-brain axis have emerged. Novel diagnostics have been developed, the clinical utility of which remains to be critically evaluated in the next coming years. New directions are also expected to lead to a larger spectrum of treatment options tailored to the individual patient. This review offers insights into emerging concepts and future directions proposed for further CIE research in dogs for the next decade to come.
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Affiliation(s)
- Albert E. Jergens
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
- *Correspondence: Albert E. Jergens
| | - Romy M. Heilmann
- Department for Small Animals, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany
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5
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Riggers DS, Gurtner C, Protschka M, Böttcher D, von Bomhard W, Alber G, Winter K, Steiner JM, Heilmann RM. Intestinal S100/Calgranulin Expression in Cats with Chronic Inflammatory Enteropathy and Intestinal Lymphoma. Animals (Basel) 2022; 12:ani12162044. [PMID: 36009635 PMCID: PMC9404432 DOI: 10.3390/ani12162044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Intestinal diseases in cats are complicated diseases in which intestinal inflammation is difficult to distinguish from lymphoma, which is a neoplasm. In this study, the expression of the proteins S100A8/A9 and S100A12 (also called calgranulins) in the intestine is investigated in both diseases and for potential correlations with microscopically visible changes in the intestine or the clinical severity of the disease. Only small differences were seen between healthy and diseased animals, and there were no differences between cats with intestinal inflammation and lymphoma. However, several correlations of cells staining positive for calgranulins and inflammatory changes at the microscopic level and clinical disease severity were shown. This indicates that calgranulins play a role in both gastrointestinal lymphoma and inflammation and would support the recent theory that these two diseases might not be separate disease entities but instead are related. Further insights into the role of the calgranulins in these feline diseases will lead to a better understanding of the disease pathogenesis and, thus, potentially novel diagnostics and treatment avenues. Abstract Diagnosing chronic inflammatory enteropathies (CIE) in cats and differentiation from intestinal lymphoma (IL) using currently available diagnostics is challenging. Intestinally expressed S100/calgranulins, measured in fecal samples, appear to be useful non-invasive biomarkers for canine CIE but have not been evaluated in cats. We hypothesized S100/calgranulins to play a role in the pathogenesis of feline chronic enteropathies (FCE) and to correlate with clinical and/or histologic disease severity. This retrospective case-control study included patient data and gastrointestinal (GI) tissues from 16 cats with CIE, 8 cats with IL, and 16 controls with no clinical signs of GI disease. GI tissue biopsies were immunohistochemically stained using polyclonal α-S100A8/A9 and α-S100A12 antibodies. S100A8/A9+ and S100A12+ cells were detected in all GI segments, with few significant differences between CIE, IL, and controls and no difference between diseased groups. Segmental inflammatory lesions were moderately to strongly correlated with increased S100/calgranulin-positive cell counts. Clinical disease severity correlated with S100A12+ cell counts in cats with IL (ρ = 0.69, p = 0.042) and more severe diarrhea with colonic lamina propria S100A12+ cells with CIE (ρ = 0.78, p = 0.021) and duodenal S100A8/A9+ cells with IL (ρ = 0.71, p = 0.032). These findings suggest a role of the S100/calgranulins in the pathogenesis of the spectrum of FCE, including CIE and IL.
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Affiliation(s)
- Denise S. Riggers
- Small Animals Department, College of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
| | - Corinne Gurtner
- Institute of Animal Pathology, Department of Infectious Diseases and Pathobiology (DIP), Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland
| | - Martina Protschka
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
| | - Denny Böttcher
- Institute of Veterinary Pathology, College of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
| | | | - Gottfried Alber
- Institute of Immunology/Molecular Pathogenesis, Center for Biotechnology and Biomedicine, College of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
| | - Karsten Winter
- Institute of Anatomy, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Joerg M. Steiner
- Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Romy M. Heilmann
- Small Animals Department, College of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany
- Correspondence:
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Siel D, Beltrán CJ, Martínez E, Pino M, Vargas N, Salinas A, Pérez O, Pereira I, Ramírez-Toloza G. Elucidating the Role of Innate and Adaptive Immune Responses in the Pathogenesis of Canine Chronic Inflammatory Enteropathy-A Search for Potential Biomarkers. Animals (Basel) 2022; 12:1645. [PMID: 35804545 DOI: 10.3390/ani12131645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/11/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Canine chronic inflammatory enteropathy (CIE) is a chronic disease affecting the small or large intestine and, in some cases, the stomach of dogs. This gastrointestinal disorder is common and is characterized by recurrent vomiting, diarrhea, and weight loss in affected dogs. The pathogenesis of IBD is not completely understood. Similar to human IBD, potential disease factors include genetics, environmental exposures, and dysregulation of the microbiota and the immune response. Some important components of the innate and adaptive immune response involved in CIE pathogenesis have been described. However, the immunopathogenesis of the disease has not been fully elucidated. In this review, we summarized the literature associated with the different cell types and molecules involved in the immunopathogenesis of CIE, with the aim of advancing the search for biomarkers with possible diagnostic, prognostic, or therapeutic utility. Abstract Canine chronic inflammatory enteropathy (CIE) is one of the most common chronic gastrointestinal diseases affecting dogs worldwide. Genetic and environmental factors, as well as intestinal microbiota and dysregulated host immune responses, participate in this multifactorial disease. Despite advances explaining the immunological and molecular mechanisms involved in CIE development, the exact pathogenesis is still unknown. This review compiles the latest reports and advances that describe the main molecular and cellular mechanisms of both the innate and adaptive immune responses involved in canine CIE pathogenesis. Future studies should focus research on the characterization of the immunopathogenesis of canine CIE in order to advance the establishment of biomarkers and molecular targets of diagnostic, prognostic, or therapeutic utility.
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7
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Kopper JJ, Iennarella-Servantez C, Jergens AE, Sahoo DK, Guillot E, Bourgois-Mochel A, Martinez MN, Allenspach K, Mochel JP. Harnessing the Biology of Canine Intestinal Organoids to Heighten Understanding of Inflammatory Bowel Disease Pathogenesis and Accelerate Drug Discovery: A One Health Approach. Front Toxicol 2022; 3:773953. [PMID: 35295115 PMCID: PMC8915821 DOI: 10.3389/ftox.2021.773953] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022] Open
Abstract
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.
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Affiliation(s)
- Jamie J Kopper
- Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,SMART Translational Medicine, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Chelsea Iennarella-Servantez
- SMART Pharmacology, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,SMART Translational Medicine, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Albert E Jergens
- Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Dipak K Sahoo
- Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,SMART Translational Medicine, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Emilie Guillot
- 3D Health Solutions, Inc., ISU Research Park, Ames, IA, United States
| | - Agnes Bourgois-Mochel
- Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Marilyn N Martinez
- Office of New Animal Drug Evaluation, Center for Veterinary Medicine, Food and Drug Administration, Rockville, MD, United States
| | - Karin Allenspach
- Veterinary Clinical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,SMART Translational Medicine, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,3D Health Solutions, Inc., ISU Research Park, Ames, IA, United States
| | - Jonathan P Mochel
- SMART Pharmacology, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,SMART Translational Medicine, Biomedical Sciences, Iowa State University College of Veterinary Medicine, Ames, IA, United States.,3D Health Solutions, Inc., ISU Research Park, Ames, IA, United States
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8
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Cabrera-García AI, Protschka M, Alber G, Kather S, Dengler F, Müller U, Steiner JM, Heilmann RM. Dysregulation of gastrointestinal RAGE (receptor for advanced glycation end products) expression in dogs with chronic inflammatory enteropathy. Vet Immunol Immunopathol 2021; 234:110216. [PMID: 33636544 DOI: 10.1016/j.vetimm.2021.110216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/11/2021] [Accepted: 02/13/2021] [Indexed: 12/18/2022]
Abstract
The pathogenesis of chronic inflammatory enteropathies (CIE) in dogs involves dysregulated innate immune responses. The receptor for advanced glycation end products (RAGE), a pattern recognition receptor, plays a role in chronic inflammation. Abrogation of proinflammatory RAGE signaling by ligand binding (e.g., S100/calgranulins) to soluble RAGE (sRAGE) might also be a novel therapeutic avenue. Serum sRAGE levels are decreased in canine CIE, but gastrointestinal tissue RAGE expression has not been investigated in dogs. Thus, the study aimed to evaluate the gastrointestinal mucosal RAGE expression in dogs with CIE. Further, the potential binding of RAGE to canine S100/calgranulin ligands was investigated. Epithelial RAGE expression was quantified in gastrointestinal (gastric, duodenal, ileal, and colonic) biopsies from 12 dogs with CIE and 9 healthy control dogs using confocal laser scanning microscopy. RAGE expression was compared between both groups of dogs and was tested for an association with patient characteristics, clinical variables, histologic lesion severity, and biomarkers of extra-gastrointestinal disease, systemic or gastrointestinal inflammation, function, or protein loss. Statistical significance was set at p < 0.05. RAGE:S100/calgranulin binding was assessed by immunoassay and electrophoretic techniques. RAGE expression was detected in all 59 biopsies from diseased and healthy control dogs evaluated. Epithelial RAGE expression in the duodenum and colon was significantly higher in dogs with CIE than in healthy controls (p < 0.04). Compared to healthy controls, RAGE expression in dogs with CIE also tended to be higher in the ileum but lower in the stomach. A slight (statistically not significant) shift towards more basal intestinal epithelial RAGE expression was detected in CIE dogs. Serum sRAGE was proportional to epithelial RAGE expression in the duodenum (p < 0.04), and RAGE expression in the colon inversely correlated with biomarkers of protein loss in serum (both p < 0.04). Several histologic morphologic and inflammatory lesion criteria and markers of inflammation (serum C-reactive protein and fecal calprotectin concentration) were related to epithelial RAGE expression in the duodenum, ileum, and/or colon. in vitro canine RAGE:S100A12 binding appeared more pronounced than RAGE:S100A8/A9 binding. This study showed a dysregulation of epithelial RAGE expression along the gastrointestinal tract in dogs with CIE. Compensatory regulations in the sRAGE/RAGE axis are an alternative explanation for these findings. The results suggest that RAGE signaling plays a role in dogs with CIE, but higher anti-inflammatory decoy receptor sRAGE levels paralleled RAGE overexpression. Canine S100/calgranulins were demonstrated to be ligands for RAGE.
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Affiliation(s)
- A I Cabrera-García
- Department for Small Animals, Veterinary Teaching Hospital, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany
| | - M Protschka
- Institute of Immunology, College of Veterinary Medicine, Biotechnological-Biomedical Center, University of Leipzig, Leipzig, SN, Germany
| | - G Alber
- Institute of Immunology, College of Veterinary Medicine, Biotechnological-Biomedical Center, University of Leipzig, Leipzig, SN, Germany
| | - S Kather
- Department for Small Animals, Veterinary Teaching Hospital, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany
| | - F Dengler
- Institute of Veterinary Physiology, University of Leipzig, Leipzig, SN, Germany
| | - U Müller
- Institute of Immunology, College of Veterinary Medicine, Biotechnological-Biomedical Center, University of Leipzig, Leipzig, SN, Germany
| | - J M Steiner
- Gastrointestinal Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - R M Heilmann
- Department for Small Animals, Veterinary Teaching Hospital, College of Veterinary Medicine, University of Leipzig, Leipzig, SN, Germany.
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