9 research outputs found
A Novel Model of TH2-polarized Chronic Ileitis: The SAMP1 Mouse
Background & Aims—SAMP1/Yit mice develop spontaneous, segmental, transmural ileitis
recapitulating many features of Crohn’s disease (CD). The ileitic phenotype may have arisen
during crosses of SAMP1 mice selected for the presence of skin lesions. We hereby describe that
the original SAMP1 strain similarly develops ileitis. Our aim was to characterize the
histopathological and immunological features of this model and assess its responsiveness to
standard IBD therapy.
Methods—The time course of histopathological features of ileitis was assessed. Immune
compartments were characterized by flow cytometry. Ileal cytokine profiles and transcription
factors were determined by real-time RT-PCR. Finally, response to corticosteroid therapy and its
effect on immune compartments and cellularity was evaluated.
Results—Histological features and time course of disease were conserved, compared to those
reported in SAMP1/Yit strains, with similar expansion of CD19+, CD4+ and CD8+ effector
(CD44highCD62Llow), and central memory lymphocytes (CD44highCD62Lhigh). However,
different from SAMP1/YitFc mice, analysis of ileal cytokine profiles revealed initial TH1
polarization followed by TH2-polarized profile accompanied by prominent eosinophilia during
late disease. Lastly, corticosteroids attenuated ileitis resulting in decreased lymphocyte subsets and
cellularity of compartments.
Conclusions—Here we report that the ileitic phenotype of SAMP1-related strains was already
present in the original SAMP1 strain. By contrast the cytokine profile within terminal ilea of
SAMP1 is distinct from the mixed TH1/TH2 profile of SAMP1/YitFc mice during late disease, as
it shows predominant TH2 polarization. Dissemination of these strains may advance our
understanding of CD pathogenesis, which in 60% of patients involves the terminal ileum