RESUMEN
OBJECTIVE: Chondrocutaneous composite grafts figure among the reconstruction alternatives for alar rim defects resulting from tumor resection and trauma. The major problem with composite grafts is the limited graft survival area. In the present study, the authors aimed to increase the survival area of composite grafts by utilizing the ability of stem cells to promote neovascularization which is crucial in composite graft viability. METHODS: The study included 36 adult Wistar Albino rats, which were allocated to 6 groups. Groups 1, 2, and 3 were the groups in which the grafts were implanted immediately after the defect was formed, and Groups 4, 5, and 6 were those in which grafts were adapted 4 days after the defect was formed. Composite grafts of 1â×â1âcm containing both the cartilage and the skin were prepared from 1 ear, and after forming punctures and incisions on the cartilage, the grafts were adapted to the 1â×â1âcm defects on the back. The backs of the rats in groups 1 and 4 were injected with adipose-derived stem cell (ADSC), those in groups 2 and 5 with medium solution, while the rats in Groups 3 and 6 did not receive any injection. The procedures were followed by histopathological and scintigraphic evaluations. RESULTS: An evaluation of the statistical results showed that composite graft survival areas of the group treated with stem cells increased significantly, in comparison with control and medium groups. When scintigraphic evaluations were considered, it was seen that the group treated with stem cells had significantly higher radioactive substance retention than the control group. Histopathological examination demonstrated that microscopic survival rates in the stem cell group were higher than those in the control group. Green fluorescent protein (GFP) was used in the experiment to tag adipose tissue-derived stem cells. Immunofluorescence staining studies showed less apoptosis and fewer GFP (+) stem cells in the composite grafts of the stem cell group. However, apoptosis was more severe in the control and medium groups which also had decreased vascularity in the graft. DISCUSSION: As the authors have shown in the present study, ADSCs have favorable effects on the viability of composite grafts. They have increased the survival rate of the grafts to a considerable extent. As a clinical implication of this experimental study, the authors think that in the patient of auricular and nasal defects involving the cartilage and the skin, injection of the ADSC and the adaptation of composite grafts 4 days after the preparation of the receiving bed may increase the composite graft viability rates. Thus, it has been found that if the composite grafts are implanted 4 days after stem cell injection, the injection of adipose tissue-derived mesenchymal stem cells is useful in enhancing the survival of composite grafts.
Asunto(s)
Tejido Adiposo/trasplante , Cartílago/trasplante , Supervivencia de Injerto , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/citología , Trasplante de Piel/métodos , Traumatismos de los Tejidos Blandos/cirugía , Animales , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas WistarRESUMEN
OBJECTIVE: Interpolation flaps are commonly used in plastic surgery to cover wide and deep defects. The need to, wait for 2 to 3 weeks until the division of the pedicle still, however, poses a serious challenge, not only extending treatment and hospital stay, but also increasing hospital expenses. To solve this problem, we have aimed to use the angiogenic potential of stem cells to selectively accelerate neovascularization with a view to increasing the viability of interpolation flaps and achieving early pedicle removal. MATERIALS AND METHODS: A total of 32 rats were allocated to 2 groups as control (N = 16) and experiment (N = 16). The cranial flaps 6 × 5 cm in size located on the back of the rats were raised. Then, a total suspension containing 3 × 10(6) adipose-derived mesenchymal stem cells (ADSC) tagged with a green fluorescent protein (GFP) was injected diffusely into the distal part of the flap, receiving bed, and wound edges. In the control group, only a medium solution was injected into the same sites. After covering the 3 × 5 cm region in the proximal part of the area where the flap was removed, the distal part of the flap was adapted to the uncovered distal area. The pedicles of 4 rats in each group were divided on postoperative days 5, 8, 11, and 14. The areas were photographed 7 days after the pedicles were released. The photographs were processed using Adobe Acrobat 9 Pro software (San Jose, CA) to measure the flap survival area in millimeters and to compare groups. Seven days after the flap pedicle was divided, the rats were injected with 250 mCi Tc-99 mm (methoxy-isobutyl-isonitrie) from the penile vein, and scintigraphic images were obtained. The images obtained from each group were subjected to a numerical evaluation, which was then used in the comparison between groups. The flaps were then examined by histology to numerically compare the number of newly formed vessels. Neovascularization was also assessed by microangiography. In addition, radiographic images were obtained by mammography and evaluated quantitatively. RESULTS: An evaluation of statistical results revealed a significant increase in the flap survival area of the group on stem cell treatment in comparison to the control group. In scintigraphic examinations, the rate of radioactive substance retention was significantly higher in the stem cell group, relative to the control group. Histopathologic examination showed that the capillary density in the stem cell group was higher than that in the control group. Green fluorescent protein had been used to label ADSC in the experiment and it was found by immunofluorescence staining that endothelial samples of control animals did not have GFP (+) cells, whereas all the animals in the experiment group had GFP (+) cells. The comparison of microangiographic images of the experiment and control groups demonstrated significantly elevated vascularity in the former, relative to the latter. DISCUSSION: It has been established in the current study that ADSC injection worked well in speeding up the neovascularization of interpolated flaps and reducing the time of pedicle division. It seems possible to minimize the morbidity of interpolated skin flaps with mesenchymal stem cell therapy at an appropriate dose and for an appropriate length of time.