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Concentrations of cysteinyl leukotrienes in urine and bronchoalveolar lavage fluid of cats with experimentally induced asthma

Carol R. NorrisDepartment of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Kendra C. DecileDepartment of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.
Present address is the Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802.

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Londa J. BerghausDepartment of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Roy D. BerghausDepartment of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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William F. WalbyDepartments of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Edward S. SchelegleDepartments of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Dallas M. HydeDepartments of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Laurel J. GershwinDepartment of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616-8734.

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Abstract

Objective—To evaluate changes in cysteinyl leukotriene (LT) concentrations in urine and bronchoalveolar lavage fluid (BALF) in cats with experimentally induced asthma.

Animals—19 cats with experimentally induced asthma and 5 control cats.

Procedure—Cats were sensitized to Bermuda grass or house dust mite allergen, and phenotypic features of asthma were confirmed with intradermal skin testing, evaluation of BALF eosinophil percentages, and pulmonary function testing. A competitive ELISA kit for LTC4, LTD4, and LTE4 was used for quantitative analysis of LTs. Urinary creatinine concentrations and BALF total protein (TP) concentrations were measured, and urinary LT-to-creatinine ratios and BALF LTto- TP ratios were calculated.

Results—Mean urinary LT-to-creatinine ratios did not differ significantly between control cats and allergensensitized cats before or after sensitization and challenge exposure with saline (0.9% NaCl) solution or allergen, respectively. In BALF, the mean LT-to-TP ratio of control cats did not differ significantly before or after sensitization and challenge exposure with saline. Asthmatic cats had BALF LT-to-TP ratios that were significantly lower than control cats at all time points, whereas ratios for asthmatic cats did not differ significantly among the various time points.

Conclusions and Clinical Relevance—Although LTs were readily detectable in urine, no significant increases in urinary LT concentrations were detected after challenge in allergen-sensitized cats. Spot testing of urinary LT concentrations appears to have no clinical benefit for use in monitoring the inflammatory asthmatic state in cats. The possibility that cysteinyl LTs bind effectively to their target receptors in BALF and, thus, decrease free LT concentrations deserves further study. (Am J Vet Res 2003;64:1449–1453)

Abstract

Objective—To evaluate changes in cysteinyl leukotriene (LT) concentrations in urine and bronchoalveolar lavage fluid (BALF) in cats with experimentally induced asthma.

Animals—19 cats with experimentally induced asthma and 5 control cats.

Procedure—Cats were sensitized to Bermuda grass or house dust mite allergen, and phenotypic features of asthma were confirmed with intradermal skin testing, evaluation of BALF eosinophil percentages, and pulmonary function testing. A competitive ELISA kit for LTC4, LTD4, and LTE4 was used for quantitative analysis of LTs. Urinary creatinine concentrations and BALF total protein (TP) concentrations were measured, and urinary LT-to-creatinine ratios and BALF LTto- TP ratios were calculated.

Results—Mean urinary LT-to-creatinine ratios did not differ significantly between control cats and allergensensitized cats before or after sensitization and challenge exposure with saline (0.9% NaCl) solution or allergen, respectively. In BALF, the mean LT-to-TP ratio of control cats did not differ significantly before or after sensitization and challenge exposure with saline. Asthmatic cats had BALF LT-to-TP ratios that were significantly lower than control cats at all time points, whereas ratios for asthmatic cats did not differ significantly among the various time points.

Conclusions and Clinical Relevance—Although LTs were readily detectable in urine, no significant increases in urinary LT concentrations were detected after challenge in allergen-sensitized cats. Spot testing of urinary LT concentrations appears to have no clinical benefit for use in monitoring the inflammatory asthmatic state in cats. The possibility that cysteinyl LTs bind effectively to their target receptors in BALF and, thus, decrease free LT concentrations deserves further study. (Am J Vet Res 2003;64:1449–1453)