Ana Beatriz Almeida

New Source of Muscle-Derived Stem Cells with Potential for Alveolar Bone Reconstruction in Cleft Lip and/or Palate Patients

Cleft lip and palate (CLP), one of the most frequent congenital malformations, affects the alveolar bone in the great majority of the cases, and the reconstruction of this defect still represents a challenge in the rehabilitation of these patients. One of the current most promising strategy to achieve this goal is the use of bone marrow stem cells (BMSC); however, isolation of BMSC or iliac bone, which is still the mostly used graft in the surgical repair of these patients, confers site morbidity to the donor. Therefore, in order to identify a new alternative source of stem cells with osteogenic potential without conferring morbidity to the donor, we have used orbicular oris muscle (OOM) fragments, which are regularly discarded during surgery repair (cheiloplasty) of CLP patients. We obtained cells from OOM fragments of four unrelated CLP patients (CLPMDSC) using previously described preplating technique. These cells, through flow cytometry analysis, were mainly positively marked for five mesenchymal stem cell antigens (CD29, CD90, CD105, SH3, and SH4), while negative for hematopoietic cell markers, CD14, CD34, CD45, and CD117, and for endothelial cell marker, CD31. After induction under appropriate cell culture conditions, these cells were capable to undergo chondrogenic, adipogenic, osteogenic, and skeletal muscle cell differentiation, as evidenced by immunohistochemistry. We also demonstrated that these cells together with a collagen membrane lead to bone tissue reconstruction in a critical-size cranial defects previously induced in nonimmunocompromised rats. The presence of human DNA in the new bone was confirmed by PCR with human-specific primers and immunohistochemistry with human nuclei antibodies. In conclusion, we showed that cells from OOM have phenotypic and behavior characteristics similar to other adult stem cells, both in vitro and in vivo. Our findings suggest that these cells represent a promising source of stem cells for alveolar bone grafting treatment, particularly in young CLP patients.

Two-stage surgical treatment of severe cherubism.

Cherubism is an autosomal-dominant syndrome characterized by excessive bilateral maxillomandibular bony degeneration followed by fibrous tissue hyperplasia. Eight patients (age, 6–15 years; mean, 11 years) with severe cherubism were treated with a 2-stage operation by the same senior surgeon (C.M.R.-A.) over an 18-year period, 1987 through 2005. Severity was based on a modified Motamedi classification system. The diagnosis was established clinically, radiographically, and histologically. Postoperative follow up ranged from 2 to 18 years (mean, 5.1 years). All patients underwent 2-stage surgical treatment. In the first stage, the anterior wall of the maxilla was osteotomized and removed (n = 5). The cherubic lesion was curetted from the maxilla and orbits. The maxilla was recontoured on the back table and then fixed orthotopically with wires. Alternatively, cortical bone windows were created, the maxillary and orbital lesions were curetted, and the maxilla was infractured and recontoured in situ with manual pressure (n = 3). Six months after the maxillary/orbital procedure, all patients underwent second-stage curettage and recontouring of the mandible using bony access windows and manual infracture. Satisfactory esthetic results were achieved in all patients. The patients remained clinically and radiographically disease-free throughout the follow-up period. The most profoundly affected patient sustained bilateral lower eyelid ectropion that resolved with full-thickness skin grafting. Although cherubism tends to abate by the fourth decade of life, early 2-stage surgical curettage provides a simple and reliable treatment that not only delivers immediate results, but also seems to arrest the growth of any remaining cherubic tissue.

Alveolar osseous defect in rat for cell therapy: preliminary report

PURPOSE To study were to reproduce an alveolar bone defect model in Wistar rats to be used for testing the efficacy of stem cell therapies. Additionally, we also aimed to determine the osteogenesis process of this osseous defect in the 1 month period post-surgery. METHODS The animals were randomly divided into two groups of 7 animals each. A gingivobuccal incision was made, and a bone defect of 28 mm(2) of area was performed in the alveolar region. Animals were killed at 2 weeks after surgery (n=7) and 4 weeks after surgery (n=7). RESULTS The average area of the alveolar defect at time point of 2 weeks was 22.27 +/- 1.31 mm(2) and the average area of alveolar defect at time point of 4 weeks was 9.03 +/- 1.17 mm(2). The average amount of bone formation at time point of 2 weeks was 5.73 +/- 1.31 mm(2) and the average amount of bone formation at time point of 4 weeks was 19 +/- 1.17 mm(2). Statistically significant differences between the amount of bone formation at 2 weeks and 4 weeks after surgery were seen (p=0.003). CONCLUSION The highest rate of ossification occurred mostly from 2 to 4 weeks after surgery. This observation suggests that 4 weeks after the bone defect creation should be a satisfactory timing to assess the potential of bone inductive stem cells to accelerate bone regeneration in Wistar rats.

Is bone transplantation the gold standard for repair of alveolar bone defects

New strategies to fulfill craniofacial bone defects have gained attention in recent years due to the morbidity of autologous bone graft harvesting. We aimed to evaluate the in vivo efficacy of bone tissue engineering strategy using mesenchymal stem cells associated with two matrices (bovine bone mineral and α-tricalcium phosphate), compared to an autologous bone transfer. A total of 28 adult, male, non-immunosuppressed Wistar rats underwent a critical-sized osseous defect of 5 mm diameter in the alveolar region. Animals were divided into five groups. Group 1 (n = 7) defects were repaired with autogenous bone grafts; Group 2 (n = 5) defects were repaired with bovine bone mineral free of cells; Group 3 (n = 5) defects were repaired with bovine bone mineral loaded with mesenchymal stem cells; Group 4 (n = 5) defects were repaired with α-tricalcium phosphate free of cells; and Group 5 (n = 6) defects were repaired with α-tricalcium phosphate loaded with mesenchymal stem cells. Groups 2–5 were compared to Group 1, the reference group. Healing response was evaluated by histomorphometry and computerized tomography. Histomorphometrically, Group 1 showed 60.27% ± 16.13% of bone in the defect. Groups 2 and 3 showed 23.02% ± 8.6% (p = 0.01) and 38.35% ± 19.59% (p = 0.06) of bone in the defect, respectively. Groups 4 and 5 showed 51.48% ± 11.7% (p = 0.30) and 61.80% ± 2.14% (p = 0.88) of bone in the defect, respectively. Animals whose bone defects were repaired with α-tricalcium phosphate and mesenchymal stem cells presented the highest bone volume filling the defects; both were not statistically different from autogenous bone.

Histological and radiological changes in cranial bone in the presence of bone wax

PURPOSE To quantify the amount of bone formation in the calvarial region of Wistar rats after craniotomy using bone wax as a haemostatic agent. METHODS Surgery to produce bilateral, symmetric, full-thickness cranial defects (area: 18 mm(2)) was performed in eight animals. The right side of the cranium remained open and the edges of the left side osseous defect was covered with bone wax. Calvaria were imaged immediately after surgery and 12 weeks postoperatively by computerized tomography. The areas of the bone defects were measured in three-dimensional images using Magics 13.0 (Materialise-Belgic, software CAD). RESULTS The average amount of bone formation on the left and right side respectively was 4.85 mm(2) and 8.16 mm(2). Statistically significant differences between the amount of bone formation on the left and right sides were seen. CONCLUSIONS Bone wax significantly diminishes the rate of bone formation in calvarial defects in a rat model.

Estudo CUMPRO: CUMPrimento do Rastreio Oncológico em profissionais de um ACeS

Objectives: Cancer is the second leading cause of death in Portugal. The National Oncology Surveillance Plan includes screening programs for colorectal, breast and cervical cancer. The goal of this study was to assess compliance with cancer screening programs among professionals in a group of health centres. Study design: Cross-sectional study. Participants: All professionals in the ACeS Povoa de Varzim/Vila do Conde group of health centres who were eligible for cancer screening. Methods: Participants were asked to complete an anonymous questionnaire about their compliance with cancer screening programs or their reasons for non-compliance. The questionnaires were distributed between February and April 2015. Compliance was assessed based on the performance indicators for cancer screening used in primary health care in 2014. Results: The response rate was 87.7% as 267 questionnaires were returned from 307 eligible participants. Eight questionnaires were excluded. The median age of participants was 41 years. Compliance with screening recommendations was found among 82.2%. Compliance with colorectal cancer screening was found among 77.8%, breast cancer screening in 84.1%, and cervix cancer screening in 87.6%. Conclusions: Professionals in this population had good compliance with current cancer screening recommendations. This study may serve as a basis for comparison for future studies.

Effects of uterine cervix constriction on Wistar rats.

PURPOSE To verify if uterine cerclage can induce craniosynostosis or any cranial deformity in new born Wistar rats. METHODS One pregnant female Wistar rat underwent laparotomy on day 18 of gestation and the uterus cervix was closed with a 3-0 nylon suture to avoid delivery, that occurs normally on the 21 day. The suture was released after 48 hours beyond the normal gestation period. The female rat delivered 11 pups. Six surviving rats from the delivery (group A - constrained group). Two rats were born from another mother and in the same age were used as control group (group B - 2 nonconstrained controls) were allowed to grow. They were sacrificed 1.2 years after their birth all the eight animals. Linear measurement, routine histology and computed tomography of the skull were performed at the time of their death to evaluate the cranial asymmetries by measurements of the anatomical landmarks of the craniofacial skeleton of the rats on the two groups and compared then. RESULTS We did not observe statistically significant differences in any of the compared measurements (p>0.05) obtained through the morphologic and radiologic methods. Histologic examinations did not reveal any sign of premature fusion or suture imbrications. Critical decrease in longitudinal body size was noticed as the limbs too in all the animals of group A. CONCLUSION Constriction of uterine cervix leads to fetus suffering, even death for a few animals, associated to small body size, but not to craniosynostosis.