Tissue engineering strategies combining molecular targets against inflammation and fibrosis, and umbilical cord blood stem cells to improve hampered muscle and skin regeneration following cleft repair

Abstract

Cleft lip with or without cleft palate is a congenital deformity that occurs in about 1 of 700 newborns, affecting the dentition, bone, skin, muscles and mucosa in the orofacial region. A cleft can give rise to problems with maxillofacial growth, dental development, speech, and eating, and can also cause hearing impairment. Surgical repair of the lip may lead to impaired regeneration of muscle and skin, fibrosis, and scar formation. This may result in hampered facial growth and dental development affecting oral function and lip and nose esthetics. Therefore, secondary surgery to correct the scar is often indicated. We will discuss the molecular and cellular pathways involved in facial and lip myogenesis, muscle anatomy in the normal and cleft lip, and complications following surgery. The aim of this review is to outline a novel molecular and cellular strategy to improve musculature and skin regeneration and to reduce scar formation following cleft repair. Orofacial clefting can be diagnosed in the fetus through prenatal ultrasound screening and allows planning for the harvesting of umbilical cord blood stem cells upon birth. Tissue engineering techniques using these cord blood stem cells and molecular targeting of inflammation and fibrosis during surgery may promote tissue regeneration. We expect that this novel strategy improves both muscle and skin regeneration, resulting in better function and esthetics after cleft repair.

Keywords: cleft lip and palate; oral surgery; scarring; tissue engineering; umbilical cord blood stem cells.

Figure 1

A, Unoperated orofacial clefting in mild to severe form, left to right: unilateral subepithelial cleft lip, unilateral cleft lip and palate, bilateral cleft lip alveolus. B, Lip closure with an optimal, normal and suboptimal esthetic outcome. B left: unilateral cleft lip with well‐aligned vermillion border, normal lip length, and normal shape of nostrils. B middle: unilateral cleft lip and palate with deficient lateral vermillion and white roll malalignment. B right: bilateral cleft lip and palate after surgical closing with vermillion notching, short upper lip, and high rising nostrils. C, Left: unoperated cleft lip and palate with cleft in the alveolar ridge and anterior displacement of the premaxilla. C middle: cleft palate with excessive scarring, and fistula following surgery. C right: adult patient in profile with a hypoplastic maxilla due to scarring after cleft lip and palate closure that resulted to a class III skeletal jaw relation [Color figure can be viewed at wileyonlinelibrary.com]

Figure 2

Left: Muscle complex involved in the function of the upper lip: seven pairs of facial and lip muscles connected to the circular orbicularis oris muscle (red: superficial fibers, blue; deep fibers); buccinator (1), levator labii superioris (2), levator labii superioris alaeque nasi (3), levator anguli oris (4), zygomaticus minor (5), zygomaticus major (6), and the risorius muscle (7). Middle: unilateral cleft lip with abnormal orientation and insertion of the orbicularis oris muscle, superficial muscle fibers (red) and deep muscle fibers (blue) are deficient. Right: bilateral cleft lip with abnormal orientation and insertion of the orbicularis oris muscle [Color figure can be viewed at wileyonlinelibrary.com]

Figure 3

Immunofluorescence staining of muscle fiber formation from masseter satellite cells (SCs): Left: after 3 days of culture, DAPI (blue) stains nuclei, Pax 7 (red), Middle: after 7 days of culture, DAPI (blue), MyHC (red). Right: after 10 days of culture DAPI (blue), MyHC (red). Magnification ×400. DAPI, 4′,6‐diamidino‐2‐phenylindole; MyHC, myosin heavy chain; Pax 7, paired box transcription factor 7 [Color figure can be viewed at wileyonlinelibrary.com]

Figure 4

Following detection of a cleft lip and/or palate (CL/P) using prenatal ultrasound screening, cord blood stem cells are isolated upon birth. These stem cells express antifibrotic factors and anti‐inflammatory factors and can be used in tissue engineering strategies in combination with factors targeting inflammation and fibrosis (e.g. anakinra, pirfenidone and nintedanib) within a scaffold during cleft surgery to promote skin and muscle regeneration and function and to inhibit scar formation [Color figure can be viewed at wileyonlinelibrary.com]