L’utilizzo di un eptapeptide marcato con fluoresceina per l'identificazione della displasia colica, in pazienti affetti da rettocolite ulcerosa: studio pilota
Aim
Targeted molecular probes have been used to detect sporadic colonic dysplasia during confocal
laser endomicroscopy (CLE) with promising results. This is a feasibility pilot study aiming
to assess the potential role of CLE combined with a fluorescent-labeled peptide to stain
and detect dysplasia associated with Ulcerative Colitis.
Method
A phage-derived heptapeptide with predicted high binding affinity for dysplastic tissue, was
synthesized and labeled with fluorescein. Eleven lesions with suspected dysplasia at endoscopy
were excised from nine patients with long-standing ulcerative colitis. Specimens were
sprayed with the peptide and examined by CLE. The CLE images were then compared to
the corresponding histological sections.
Results
At definitive histology, 4 lesions were diagnosed as inflammatory polyps, 6 as dysplastic
lesions and one as invasive cancer. In inflammatory polyps, the fluorescence signal came
from peri-cryptal spaces and crypt lumen due to passive accumulation of the peptide in
these areas. Dysplasia was associated with active binding of the peptide to dysplastic
colonocytes.
Conclusion
Ex vivo staining of ulcerative colitis-associated dysplasia using a fluorescent labeled molecular
probe and CLE is feasible. In vivo studies on larger populations are required to evaluate the safety and the effective contribution of molecular probes in cancer surveillance of ulcerative
colitis