Use of Pig as a Model for Mesenchymal Stem Cell Therapies for Bone Regeneration.

Bone is a plastic tissue with a large healing capability. However, extensive bone loss due to disease or trauma requires extreme therapy such as bone grafting or tissue-engineering applications. Presently, bone grafting is the gold standard for bone repair, but presents serious limitations including donor site morbidity, rejection, and limited tissue regeneration. The use of stem cells appears to be a means to overcome such limitations. Bone marrow mesenchymal stem cells (BMSC) have been the choice thus far for stem cell therapy for bone regeneration. However, adipose-derived stem cells (ASC) have similar immunophenotype, morphology, multilineage potential, and transcriptome compared to BMSC, and both types have demonstrated extensive osteogenic capacity both in vitro and in vivo in several species. The use of scaffolds in combination with stem cells and growth factors provides a valuable tool for guided bone regeneration, especially for complex anatomic defects. Before translation to human medicine, regenerative strategies must be developed in animal models to improve effectiveness and efficiency. The pig presents as a useful model due to similar macro- and microanatomy and favorable logistics of use. This review examines data that provides strong support for the clinical translation of the pig model for bone regeneration.

Adipose-derived mesenchymal stem cells enhance healing of mandibular defects in the ramus of swine.

PURPOSE: This study investigated the effect of adipose-derived mesenchymal stem cells (ASCs) injected locally or systemically on the bone regeneration of a 10-mm-diameter cylindrical noncritical-size defect in the ramus of the pig mandible. MATERIALS AND METHODS: Fifteen Yorkshire pigs, weighing 60 to 80 kg, received bilateral 10-mm-diameter cylindrical surgical defects in each ramus of the mandible. Pigs received 1) a direct injection into the defect of 2.5 million carboxy-fluorescein diacetate succinimidyl ester-labeled ASCs from 1 of 2 pig donors (n = 6); 2) an ear vein injection of 5 million carboxy-fluorescein diacetate succinimidyl ester-labeled ASCs from 1 of 2 pig donors (n = 6); or 3) an ear vein injection of culture Dulbecco's Modified Eagle's Medium without stem cells (control; n = 3). Pigs from each treatment were sacrificed at 1 hour, 2 weeks, or 4 weeks after surgery. Healing of the defect was evaluated by dual-energy x-ray absorptiometry, micro-computed tomography, fluorescent microscopy, and histology. RESULTS: Bone healing was accelerated in the ASC-injected treatment groups at 2 and 4 weeks after surgery compared with the control pigs. CONCLUSIONS: Results from this animal model provide evidence that the injection of ASC locally into a bone defect or systemically can accelerate the healing of bone.

Craniometric and velopharyngeal assessment of infants with and without cleft palate.

BACKGROUND: The current study was designed to obtain qualitative and quantitative information of the velopharyngeal mechanism and craniometric dimensions in infants born with a normal mechanism and in infants with an unrepaired cleft palate. MATERIALS AND METHODS: Clinical magnetic resonance imaging data were obtained from the medical charts of 4 infants (2 with cleft lip and palate and 2 without) between the ages of 8 and 9 months. Craniometric measures and levator veli palatini muscle morphology were analyzed using visualization modeling software. Both raw measures and measures normalized by head circumference were examined. RESULTS: Patients 1 and 2 demonstrated normal velopharyngeal anatomy and a similar distance between levator muscle origins (38.9-40.7 mm), sagittal angles of origin (56-57 degrees), and levator muscle bundle lengths (28.4-30.7 mm). Patients with an unrepaired cleft palate displayed smaller oblique coronal angles of origins (58-62 degrees) compared with patients without cleft palate (62-67 degrees). Patients without cleft palate showed a steeper muscle (56-57 degrees) compared with patients without cleft palate (66-67 degrees). The basion-sella-nasion angle, hard palate length, and hard palate width measurements are related systematically to head circumference in this patient group. DISCUSSION: Results from the current study are in agreement with previous studies demonstrating variations across patients with cleft palate particularly in the muscle bundle lengths, distance between muscle origins, velar thickness, and velar length. Longitudinal studies are needed to determine how levator muscle and craniometric dimensions vary between those with and without cleft palate. A larger sample size is necessary to provide statistical analysis.

Surgical management of facial skin cancer.

Surgical excision is the gold standard for management of cutaneous basal cell carcinoma or squamous cell carcinoma. Surgical management of nonmelanotic facial skin cancer requires preoperative planning and an in-depth understanding of reconstructive techniques, including primary closure, skin grafting, and local tissue flaps. The decision regarding the method of treatment of nonmelanotic skin cancer is highly individualized and depends on patient age, cancer size, histologic subtype, and site. No single therapy or technique can be used in every situation. The goals of treatment include complete removal of the lesion with preservation of normal tissue, function, and cosmesis. In this article we discuss the principles and techniques of surgical excision and reconstruction of site-specific facial skin cancers.

Magnetic resonance imaging of the levator veli palatini muscle before and after primary palatoplasty.

OBJECTIVE: To explore the application of magnetic resonance imaging (MRI) in the evaluation of patients with cleft palate before and after primary palatoplasty with particular attention focused on the levator veli palatini muscle. DESIGN: Prospective study using MRIs of subjects before and after primary cleft palate surgery. SETTING: Hospital and university based. PATIENTS: One female infant with normal anatomy. Three male and four female infants with cleft palate of varying severity. INTERVENTION: Furlow double-opposing Z-plasty and V-Y palatoplasty. MAIN OUTCOME MEASURES: Magnetic resonance images. RESULTS: It was found that the levator veli palatini muscle can be imaged before and after palatal surgery in infants using MRI. The muscle may have sufficient volume, proportionate to a normal infant or adult, in infants born with cleft palate. If retrodisplaced properly, the muscle is likely to be steeper (more vertical) from its origin at the base of the skull to its insertion into the velum following palatoplasty, thus providing a more favorable angle for elevating the velum. Following palatal surgery, the levator muscle mass may not be as cohesive across the velar midline, compared with normal musculature. CONCLUSION: MRI is a viable imaging modality for the evaluation of the anatomy of the levator veli palatini muscle before and after primary palatoplasty in infants born with cleft palate.