Objective—To evaluate changes in cysteinyl
leukotriene (LT) concentrations in urine and bronchoalveolar
lavage fluid (BALF) in cats with experimentally
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)
Objective—To compare the effects of an orally administered
corticosteroid (prednisone), an inhaled corticosteroid
(flunisolide), a leukotriene-receptor antagonist
(zafirlukast), an antiserotonergic drug (cyproheptadine),
and a control substance on the asthmatic phenotype
in cats with experimentally induced asthma.
Animals—6 cats with asthma experimentally
induced by the use of Bermuda grass allergen (BGA).
Procedures—A randomized, crossover design was
used to assess changes in the percentage of
eosinophils in bronchoalveolar lavage fluid (BALF); airway
hyperresponsiveness; blood lymphocyte phenotype
determined by use of flow cytometry; and serum
and BALF content of BGA-specific IgE, IgG, and IgA
determined by use of ELISAs.
Results—Mean ± SE eosinophil percentages in BALF
when cats were administered prednisone (5.0 ±
2.3%) and flunisolide (2.5 ± 1.7%) were significantly
lower than for the control treatment (33.7 ± 11.1%).
We did not detect significant differences in airway
hyperresponsiveness or lymphocyte surface markers
among treatments. Content of BGA-specific IgE in
serum was significantly lower when cats were treated
with prednisone (25.5 ± 5.4%), compared with values
for the control treatment (63.6 ± 12.9%); no other
significant differences were observed in content of
BGA-specific immunoglobulins among treatments.
Conclusions and Clinical Relevance—Orally administered
and inhaled corticosteroids decreased
eosinophilic inflammation in airways of cats with
experimentally induced asthma. Only oral administration
of prednisone decreased the content of BGAspecific
IgE in serum; no other significant local or systemic
immunologic effects were detected among
treatments. Inhaled corticosteroids can be considered
as an alternate method for decreasing airway
inflammation in cats with asthma. (Am J Vet Res