In vitro manipulation of cleft palate connective tissue: setting the bases of a proposed new treatment.

ABSTRACT

BACKGROUND: Palatoplasty has the undesired side effect of impaired mid-facial growth. To avoid this problem, we propose an alternative to palatoplasty. We hypothesize that if BMP-2 is injected together with a carrier into the periosteum of the cleft palate borders, border volume will increase and connective tissue cells will be activated to produce extra bone. Once these borders supported by bone reach the midline, extraction of their covering epithelia with trypsin will permit adhesion of the underlying tissues. We investigated in vitro the ability of cleft palate connective tissue cells to produce extra bone in the presence of BMP-2 and the possibility of using trypsin to remove the epithelium covering the cleft palate borders without impairing the underlying tissues' ability to adhere. MATERIALS AND METHODS: We used the cleft palate presented by tgf-beta(3) null mice and small fragments of human cleft palate mucoperiosteum as models. Immunolabeling BMP-2-treated or untreated cultures with TUNEL and anti-osteocalcin or PCNA antibodies was performed. The epithelium of the cleft palate borders was removed with a trypsin solution, and the de-epithelialized tissues were cultured in apposition. RESULTS: BMP-2 induces differentiation toward bone on cleft palate connective tissue cells without producing cell death or proliferation. Trypsin removal of the cleft palate margins' epithelium does not impair the underlying tissues' adhesion. CONCLUSION: It is possible to generate extra bone at the cleft palate margins and to chemically eliminate their covering epithelia without damaging the underlying tissues, which allows further investigation in vivo of this new approach for cleft palate closure.