Toward Microsurgical Correction of Cleft Lip Ex Utero through Restoration of Craniofacial Developmental Programs

Cleft lip with or without cleft palate is present in approximately one in 500 to 700 live births, representing the most common congenital craniofacial anomaly. Previously, the authors developed a unique murine model with compound Pbx deficiency that exhibits fully penetrant cleft lip with or without cleft palate. To investigate the possibility of tissue repair at an early gestational stage, the authors designed a minimally invasive surgical approach suitable for intrauterine repair using Wnt9b-soaked collagen microspheres to restore craniofacial developmental programs for cleft correction.

Collagen microspheres with diameters ranging from 20 to 50 μm were fabricated to serve as a delivery vehicle for Wnt9b. At gestational day 11.5, wild-type and Pbx-deficient murine embryos were isolated. Microspheres soaked in murine purified Wnt9b protein were microsurgically implanted at the midface lambdoidal junction. Embryos were cultured in a 37°C modified whole-embryo culture system.

Targeted release of Wnt9b resulted in augmented Wnt expression at the lambdoidal junction. Microsurgical implantation of Wnt9b-soaked microspheres resulted in cleft correction in 27.1 percent of the Pbx-deficient embryos. The difference in the ratio of the areas of clefting between implanted and nonimplanted embryos was significant (p < 0.05).

Ex utero correction of cleft lip with or without cleft palate in the authors' murine model by means of microsurgical intervention and targeted delivery of Wnt proteins is an innovative and promising strategy. Although further refinement and optimization of this technique will be required to improve efficacy, the authors believe that this approach will open new avenues toward unconventional prenatal interventions for patients with cleft lip with or without cleft palate, and provide future approaches for prenatal repair of other congenital head and neck disorders.