New Insights in Collagen Turnover in Orofacial Cleft Patients

Objective We aimed to characterize the fibroblast phenotype of patients by analyzing gene and protein expression of cleft lip and/or cleft palate fibroblasts in relation to collagen turnover and extracellular matrix remodeling.Patients Human palatal fibroblasts were obtained from three healthy subjects without cleft lip and/or cleft palate and from three subjects with nonsyndromic cleft lip and/or cleft palate. Collagen turnover–related gene and protein expression were analyzed by real-time polymerase chain reaction, Western and dot blots, and sodium dodecyl sulfate zymography.Results Cleft lip and/or cleft palate fibroblasts, compared with controls, displayed a down-regulation of collagens type I and III messenger RNA (p< .0001 and p< .001, respectively) but an opposite tendency to increase protein levels. Cleft lip and/or cleft palate cells had higher lysyl hydroxylase-2b messenger RNA levels expressed in relation to collagen type I messenger RNA, down-regulated matrix metalloproteinase-1, tissue inhibitor of matrix metalloproteinase-1, and Secreted Protein Acidic and Rich in Cysteine messenger RNA (p< .0001 and p< .01, respectively). Pro–matrix metalloproteinase-1 tended to decrease, and pro–matrix metalloproteinase-2 and -9 were down-regulated (p< .01, p< .05, respectively), as was Secreted Protein Acidic and Rich in Cysteine protein expression (p< .05).Conclusions Our results suggest that the cleft lip and/or cleft palate fibroblast phenotype is characterized by a tendency toward interstitial collagen deposition due to posttranslational modifications, such as decreased collagen degradation by matrix metalloproteinases and increased collagen cross-links. These findings may contribute to the knowledge of the cleft lip and/or cleft palate fibroblast phenotype and may be useful to the surgeon when considering the potential wound contraction and subsequent undesired scarring in cleft lip and/or cleft palate ocurring after the surgical closure of a cleft palate.