Mitochondrial activity of orbicularis oris muscle in unilateral cleft lip patients

Acrylated Hyaluronic-Acid Based Hydrogel for the Treatment of Craniofacial Volumetric Muscle Loss

Current treatment options for craniofacial volumetric muscle loss (VML) have disadvantages and cannot fully restore normal function. Bio-inspired semisynthetic acrylated hyaluronic acid (AcHyA) hydrogel, which fills irregularly shaped defects, resembles an extracellular matrix, and induces a minimal inflammatory response, has shown promise in experimental studies of extremity VML. We therefore sought to study AcHyA hydrogel in the treatment of craniofacial VML. For this, we used a novel model of masseter VML in the rat. Following the creation of a 5 mm × 5 mm injury to the superficial masseter and administration of AcHyA to the wound, masseters were explanted between 2 and 16 weeks postoperatively and were analyzed for evidence of muscle regeneration including fibrosis, defect size, and fiber cross-sectional area (FCSA). At 8 and 16 weeks, masseters treated with AcHyA showed significantly less fibrosis than nonrepaired controls and a smaller decrease in defect size. The mean FCSA among fibers near the defect was significantly greater among hydrogel-repaired than control masseters at 8 weeks, 12 weeks, and 16 weeks. These results show that the hydrogel mitigates the fibrotic healing response and wound contracture. Our findings also suggest that hydrogel-based treatments have potential use as a treatment for the regeneration of craniofacial VML and demonstrate a system for evaluating subsequent iterations of materials in VML injuries.

In Silico and In Vivo Studies Detect Functional Repair Mechanisms in a Volumetric Muscle Loss Injury

IMPACT STATEMENT

Despite medical advances, volumetric muscle loss (VML) injuries to craniofacial muscles represent an unmet clinical need. We report an implantable tissue-engineered construct that leads to substantial tissue regeneration and functional recovery in a preclinical model of VML injury that is dimensionally relevant to unilateral cleft lip repair, and a series of corresponding computational models that provide biomechanical insight into mechanism(s) responsible for the VML-induced functional deficits and recovery following tissue-engineered muscle repair implantation. This unique combined approach represents a critical first step toward establishing a crucial biomechanical basis for the development of efficacious regenerative technologies, considering the spectrum of VML injuries.

Histologic, histochemical, and ultrastructural analysis of soft tissues from cleft and normal lips

The cause of cleft lip remains speculative. The nature and extent of pathophysiologic changes in cleft lip muscle are controversial. This study was undertaken to better understand the developmental processes at work. There were two groups of patients. In group 1, 40 fresh tissue specimens were taken from 22 patients who were 2 to 5 months old-their age at the time of their primary cleft lip repair. In group 2, eight control specimens were collected from six children who were seen in the emergency department with lip lacerations. Fresh specimens fixed in neutral buffered formalin were evaluated by the use of hematoxylin and eosin with Luxol fast blue, Bielschowsky, and Masson trichrome stains. Fresh frozen tissue was histochemically assessed by the use of hematoxylin and eosin, modified Gomori trichrome, and adenosine triphosphatase. Ultrastructural analysis was performed on fine sections of glutaraldehyde-fixed tissue. Histologic examination revealed increased endomysial and perimysial collagen in cleft specimens with evidence of muscle-bundle size variation and nonneurogenic atrophy. Insignificant differences were observed between cleft-side and noncleft-side specimens when the means of 200 counts of neural-tissue bundles in the subdermis were compared (p = 0.093). Histochemical examination revealed no typical checkerboard pattern, but a preponderance of type 2 fiber was seen. By means of electron microscopy, increased numbers of subsarcolemmal mitochondria were found in cleft, noncleft, and control specimens. Increased absolute numbers of mitochondria and variations in size, shape, and crystal arrangement were identified. In conclusion, there is no evidence of deficient neural supply in the cleft lip. There is also no evidence of neurogenic muscle atrophy or a metabolic abnormality. There are characteristic myopathic changes. These, in concert with the observed interstitial fibrosis, may have far-reaching implications for growth and function.

Fetal unilateral cleft lip and palate: detection of enzymic anomalies in the amniotic fluid

Aims of this study were to evaluate whether it is possible to determine, by means of isoelectric focusing, an enzymic differentiation in human amniotic fluid, and whether the onset of fetal cleft lip and palate is accompanied by a pathologic enzymatic differentiation pattern in amniotic fluid. From January of 1993 to June of 1996, amniotic fluid samples from 315 healthy pregnant women (ages 22 to 43 years, mean 37 years; gestational age 14 to 22 weeks, mean 17 weeks) were examined. The normality of all pregnancies was confirmed at birth. Moreover, amniotic fluid samples were examined from three pregnancies (ages 36, 35, and 30 years; gestational ages 16, 18, 24 weeks) with fetal unilateral cleft lip and palate (confirmed at birth), diagnosed by ultrasound. The authors have tested as "metabolic" markers the enzymes lactate dehydrogenase and creatine phosphokinase. For the concentration rates of both the tested enzymes, a statistically significant difference (p = 0.003) was found between amniotic fluid samples obtained from normal and affected pregnancies. These data, in the authors' opinion, corroborate the hypothesis that a local metabolic impairment is somehow involved in the pathogenesis of cleft lip and palate.