The Role of Extracellular Vesicles Secreted From Thermal Stress-Induced Adipose-Derived Stem Cells on Bone Regeneration.

PURPOSE: Extracellular vesicles (EVs) are responsible for intercellular communication. Mesenchymal stem cell-derived vesicles have been shown to have similar properties as functional mesenchymal stem cells. The aim of this study was to compare the therapeutic benefit of EVs obtained from adipose tissue-derived stem cells (ADSC) on bone repair whereas using ß-tricalcium phosphate (ß-TCP) biomaterial as a carrier. MATERIALS AND METHOD: A single critical size bone defect of 8 mm in diameter was created on the right side of rat calvarium using a custom-made punch needle. Animals were randomly divided into 5 groups: group 1 (no treatment), group 2 (bone graft), group 3 (ß-TCP + ADSC), group 4 (ß-TCP + EV), group 5 (ß-TCP). Eight weeks later, animals were sacrificed and histologic and radiologic evaluation was performed. RESULTS: Semiquantitative histologic scoring demonstrated significantly higher bone regeneration scores for groups 2, 3, and 4 compared to group 1. Radiologic imaging showed significantly higher bone mineral density for groups 2, 3, and 5 compared to group 1. There were no significant differences between treatment groups in either histologic or radiologic scoring. CONCLUSIONS: Our data showed that EVs provided from thermally induced ADSCs did not show any significant difference in bone regeneration when compared to ADSCs themselves. Future studies should focus on determining the optimum amount and content of EV application since these vary significantly depending on the microenvironment.

Microvascular anastomosis using Ankaferd blood stopper: demonstration of long-term histopathologic effects on vascular tissue.

Ankaferd blood stopper (ABS) (Ankaferd Ilaç Kozmetik A.S., Turkey) is a medicinal plant extract, which is used in Turkish traditional medicine as a haemostatic agent. The aim of this study was to investigate the haemostatic effect of ABS in preventing microvascular leakage on an anastomosis site and to look into its long-term impact on vascular tissue. Twenty-one Wistar albino rats were randomly divided into three groups. The animals in the second and third groups were pretreated with acetylsalicylic acid. All of the right femoral arteries were divided and anastomosed in an end-to-end fashion. Following microvascular anastomosis, saline-soaked gauze tampons were applied in the first and second groups. In the third group, ABS-soaked tampons were applied to the anastomosis sites. The mean bleeding time of group 3 was significantly shorter than group 2 and group 1. Three weeks after the operation, there were aneurysms on all of the anastomosis sites in group 3 and none of the anastomoses were patent. Histologic examination demonstrated increased inflammatory cell infiltration, tunica media degeneration and contraction of tunica intima in group 3. This is the first study reporting the long-term effects of ABS on microvascular anastomosis. Contrary to previously reported studies, this agent is not appropriate for use on injured or anastomosed vessels.