title: Effects of intravenous and subcutaneous heartworm homogenate from doxycycline-treated and untreated donor dogs on bronchial reactivity and lung in cats.
abstract: A controlled, blind research study was conducted to define the innate response of lungs in specific pathogen free (SPF) cats to intravenous (n=10) or subcutaneous (n=4) administration of homogenate of adult Dirofilaria immitis from donor dogs compared with lung response in control cats (n=6). There was no difference in cats that received heartworm homogenate IV for 18 days from donor dogs treated with doxycycline for 1 month compared with cats given heartworm homogenate from untreated donor dogs. Cats did not develop clinical signs, and no radiographic changes were noted. Cats given SC heartworm homogenate at lower concentration than IV groups did not develop histologic changes. Cats that received IV heartworm homogenate for 18 days developed mild interstitial and peribronchial myofibrocyte proliferation and smooth muscle proliferation of the pulmonary arteries. Bronchial ring contractility in vitro was blunted in the IV homogenate cats to the agonists acetylcholine and 5-hydroxytryptamine. Cats in the SC group had increased sensitivity to histamine at high concentrations but normal contractility and relaxation responses to other agonists. No increase in mast cells was noted in lung tissues of cats given homogenate. In the absence of bronchial wall remodeling, cats given IV homogenate had blunted responses to bronchial constriction, but normal relaxation to nitroprusside and substance P and increased sensitivity to histamine. In the absence adult heartworms, the homogenate of adult heartworms in the circulation of SPF cats induced a direct effect on lung parenchyma and altered bronchial ring reactivity.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA. Electronic address: dilloar@auburn.edu.
authors.forename: A Ray
authors.initials: AR
authors.lastname: Dillon
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Tillson
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wooldridge
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: R
authors.initials: R
authors.lastname: Cattley
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: B
authors.initials: B
authors.lastname: Brawner
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: R
authors.initials: R
authors.lastname: Cole
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: B
authors.initials: B
authors.lastname: Welles
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: P W
authors.initials: PW
authors.lastname: Christopherson
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: T
authors.initials: T
authors.lastname: Lee-Fowler
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: S
authors.initials: S
authors.lastname: Borderlon
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: S
authors.initials: S
authors.lastname: Barney
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: S Z
authors.initials: SZ
authors.lastname: Wells
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, AL 36830, USA.
authors.forename: E B
authors.initials: EB
authors.lastname: Diffie
authors.affiliation: College of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Schachner
mesh_terms: D000818:Animals; D002415:Cats; D004183:Dirofilaria immitis / Q000276:immunology*; D004184:Dirofilariasis / Q000188:drug therapy; D004285:Dogs; D004318:Doxycycline / Q000627:therapeutic use; D007113:Immunity, Innate / Q000276:immunology*; D008168:Lung / Q000276:immunology*; D011651:Pulmonary Artery / Q000276:immunology* / Q000503:physiopathology; D013047:Specific Pathogen-Free Organisms
chemical_list: D004318:Doxycycline
keywords: Dirofilaria immitis; Feline; HARD; Heartworm; Respiratory disease