Characterizing Morphology and Nonlinear Elastic Properties of Normal and Thermally Stressed Engineered Oral Mucosal Tissues Using Scanning Acoustic Microscopy

This study examines the use of high-resolution ultrasound to monitor changes in the morphology and nonlinear elastic properties of engineered oral mucosal tissues under normal and thermally stressed culture conditions. Nonlinear elastic properties were determined by first developing strain maps from acoustic ultrasound, followed by fitting of nonlinear stress?strain data to a 1-term Ogden model. Testing examined a clinically developed ex vivo produced oral mucosa equivalent (EVPOME). As seeded cells proliferate on an EVPOME surface, they produce a keratinized protective upper layer that fills in and smoothens out surface irregularities. These transformations can also alter the nonlinear stress/strain parameters as EVPOME cells differentiate. This EVPOME behavior is similar to those of natural oral mucosal tissues and in contrast to an unseeded scaffold. If ultrasonic monitoring could be developed, then tissue cultivation could be adjusted in-process to account for biological variations in their development of the stratified cellular layer. In addition to ultrasonic testing, an in-house-built compression system capable of accurate measurements on small (?1.0?1.5?cm2) tissue samples is presented. Results showed a near 2.5-fold difference in the stiffness properties between the unstressed EVPOME and the noncell-seeded acellular scaffold (AlloDerm?). There were also 4?greater differences in root mean square values of the thickness in the unseeded AlloDerm compared to the mature unstressed EVPOME; this is a strong indicator for quantifying surface roughness.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140241/1/ten.tec.2012.0467.pd

Human Oral Mucosa Tissue-Engineered Constructs Monitored by Raman Fiber-Optic Probe

In maxillofacial and oral surgery, there is a need for the development of tissue-engineered constructs. They are used for reconstructions due to trauma, dental implants, congenital defects, or oral cancer. A noninvasive monitoring of the fabrication of tissue-engineered constructs at the production and implantation stages done in real time is extremely important for predicting the success of tissue-engineered grafts. We demonstrated a Raman spectroscopic probe system, its design and application, for real-time ex vivo produced oral mucosa equivalent (EVPOME) constructs noninvasive monitoring. We performed in vivo studies to find Raman spectroscopic indicators for postimplanted EVPOME failure and determined that Raman spectra of EVPOMEs preexposed to thermal stress during manufacturing procedures displayed correlation of the band height ratio of CH2 deformation to phenylalanine ring breathing modes, giving a Raman metric to distinguish between healthy and compromised postimplanted constructs. This study is the step toward our ultimate goal to develop a stand-alone system, to be used in a clinical setting, where the data collection and analysis are conducted on the basis of these spectroscopic indicators with minimal user intervention.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140248/1/ten.tec.2013.0622.pd

MUCOADHESIVE FILMS FOR TREATMENT OF LOCAL ORAL DISORDERS: DEVELOPMENT, CHARACTERIZATION AND \u3cem\u3eIN VIVO\u3c/em\u3e TESTING

Mucoadhesive drug delivery systems which are being used from 1980’s to avoid first pass metabolism of drugs, commercially exist for only systemic drug delivery with fast erosion times (15-60 min), that may not be appropriate for local oral disorders. The goal of this research was to develop and characterize mucoadhesive films with flexibility of carrying different drugs and proteins and provide sustained release for local treatment of oral disorders. Mucoadhesive films composed of polyvinylpyrrolidone (PVP) and carboxymethlycellulose (CMC) were formulated with imiquimod, an immune response modifier. Problems such as solubilization of imiquimod to increase drug loading, uniformity in films and total amount of drug released into supernatants were addressed by use of acetate buffer after investigating multiple methods. Subsequently, other relevant properties of mucoadhesive systems, such as adhesion (shear, pull-off), tensile properties, swelling profiles, transport kinetics, and subsequent changes in release profiles as a function of film composition were characterized. The potential of the system for local retention of imiquimod, determined in oral mucosa of hamsters showed time dependent decrease in imiquimod amount through 12 hours, with no traces of drug in blood. Further testing in humans revealed that the residence time of the mucoadhesive films depended on the application site, increasing in the order of tongue \u3c cheek \u3c gingiva. In parallel, mucoadhesive films loaded with epidermal growth factor (EGF) were developed to promote treatment of oral mucosal wounds. Bioactivity was tested in vitro on buccal tissues by creating a wound followed by application of films. Although EGF-loaded films did not accelerate wound healing, but rather elicited a hyperparakeratotic response. In vitro buccal tissues may not be appropriate for testing the effects of EGF in wound healing without incorporation of other biochemical factors. Overall, a mucoadhesive system capable of delivering bioactive small molecules and proteins in sustained manner was developed in this work. A thorough understanding of the system properties was achieved to further tune for future applications. In vitro studies and in vivo studies in hamsters and humans clearly showed the potential and usefulness of the system to translate in to clinic for treatment of oral precancerous lesions

Stem cell based therapy retards the progression of osteoarthritis and promotes repair of meniscus injury of sheep model knee joint

ABSTRACT The aim of this study to determine if intra-articular injection of autologous bone marrow mesenchymal stem cells (ABMSCs) could repair surgically induced osteoarthritis in sheep model. Eighteen male healthy sheep (weighed 18-20kg) were divided into two test groups and one control group. The control groups were not different from the test groups with respect to age and weight, but the test animals underwent a bone marrow aspira- tion for cell preparation in the same time of osteoarthritis induction. ABMSCs were isolated from sheep bone marrow and divided into two groups, namely test group A; ABMSCs cultured in FD medium supplemented with 10% fetal bovine serum (FBS), Test group B; ABMSCs were cultured in FD medium supplimented with 1% FBS and 10 ng/ml TGFβ-3 for three weeks. OA was induced by complete excision of the medial meniscus and resection of the anterior cruciate ligament (ACL). Sheep were subjected to exercise for three weeks post OA induction. After 6 weeks post-operation, test groups received direct intra-articular injection of a single dose 10x106 cells suspended in basal medium into injured sheep knee joint. Con- trol animals received basal medium alone. Six weeks post- cel injection, the femoral condyle and the tibial plateau from test and control groups were removed,fixed,photographed, and assessed by two blinded evaluators based on ICRS grading system, decalcified. Specimens were sectioned into 5 µm and stained with H & E and Safranin O. The result demonstrated that Gross observation of femoral condyle and tibia plaetue of the operated knee joint had OA. The severe OA was clearly observed in in control group knee joints. Test group received intra-articular injection of ABMSCs alone showed moderate OA. Interestingly test group B that received intra-articularinjection of TGF-β3 induced ABMSCs showed mild OA. The histological examination showed clear evidence of articular cartilage and menicscus regeneration in test group B of sheep injured knee joint that received TGF-β3 induced ABMSCs when compared with other groups