Expression of TGFβ-3, PAX9, RYK, matrix metalloproteinases and their tissue inhibitors in human cleft-affected tissue

Formation of mammalian lip and palate involves multiple developmental
steps that finally lead to the fusion of the two bilateral palatal shelves along
the facial midline. Recent studies confirm that on the basis successful orofacial formation is coordinated interactions of several factors including genes,
growth factors, enzymes and their natural inhibitors. The aim of our study
was to investigate cleft disordered tissue in children with cleft lip and palate
for detection of local expression of key regulators of palatogenesis.
The study involved 10 patients with unilateral cleft lip and palate at the
age of three months to four years and eight months. Tissue samples were
collected during the surgical procedure from the borders of the cleft region.
Material was proceed for detection of PAX9, RYK, TGFβ-3, MMP-8, MMP-9
and TIMP-2 with biotin-streptavidin immunohistochemistry. Distribution of
immunoreactive structures was detected semiquantitatively.
Expression of PAX9 and RYK was more pronounced in cleft lip and palate
disordered epithelium. The relative number of PAX9 positive epitheliocytes
was very variable, while RYK mainly stained few cells localized into middle
layers. Expression of TGFβ-3 was detected in the tissue of all patients. We saw
numerous positive epitheliocytes in eight cases, but underlying connective
tissue mainly demonstrated few or moderate number immunoreactive cells.
Expression of MMP-8 was found only in epithelium of eight patients and it
was slight, while MMP-9 and TIMP-2 marked variable number of positive
epithelial and connective tissue cells.
Conclusions. Expression of Pax-9 is more characteristic for cleft lip and
palate affected tissue and probably facilitates tissue reconstruction due to its
mitogenic effect. Rich expression of TGFβ-3 in cleft lip and palate disordered
tissue may play a role in successful tissue remodelling and scar-free healing.
Cleft lip and palate disordered tissue are characterizied by more pronounced
expression of MMP-9, it slightly predominate expression of TIMP-2, giving
evidence to the involvement of mentioned factors in the postnatal tissue
remodeling.