A comparative evaluation of the effect of platelet rich fibrin matrix with and without peripheral blood mesenchymal stem cells on dental implant stability: A randomized controlled clinical trial

Technological advances in the field of implantology have led to the concept of surface modifications to enhance implant stability by utilization of current concepts of tissue engineering and materials such as platelet concentrates and stem cells. The purpose of the present randomized controlled clinical trial was to evaluate and compare the effect of platelet rich fibrin matrix (PRFM) with and without peripheral blood mesenchymal stem cells (PBMSCs) on implant stability; by assessing the bone to implant contact (BIC) using resonance frequency analysis (RFA), insertion torque and also to establish and correlate the same with implant stability quotient (ISQ). A total of 15 patients with 30 sites ensuring a minimum of two dental implants adjacently placed in an edentulous area; with the age group of 25-50 years of both the sexes were categorized into Group 1 (dental implant with PRFM) and Group 2 (dental implant with PBMSCs embedded in PRFM). Insertion torque values at the time of dental implant placement and ISQ using RFA was recorded at 1 week, 1 month, and 3 months post operatively. There was no significant difference (p = 0.81) in Insertion torque values between both the groups (G1 and G2). Platelet rich fibrin matrix along with PBMSCs enhanced implant stability as higher and statistically significant ISQ values were noted at 1 week (p = 0.18), 1 month (p ≤ 0.001), and 3 months (p ≤ 0.001) intervals in the G2 group. Platelet rich fibrin matrix and PBMSCs showed promising results as a potential regenerative material for increasing and enhancing BIC and hence implant stability.

Characterization and Differentiation of Circulating Blood Mesenchymal Stem Cells and the Role of Phosphatidylinositol 3-Kinase in Modulating the Adhesion

Bone marrow mesenchymal stem cells (BM MSCs) can differentiate into multi-lineage tissues. However, obtaining BM MSCs by aspiration is difficult and can be painful; therefore peripheral blood (PB) MSCs might provide an easier alternative for clinical applications. Here, we show that circulating PB MSCs proliferate as efficiently as BM MSCs in the presence of extracellular matrix (ECM) and that differentiation potential into osteoblast in vitro and in vivo. Both BM MSCs and PB MSCs developed into new bone when subcutaneously transplanted into immune-compromised mice using hydroxyapatite/tricalcium phosphate as a carrier. Furthermore, LY294002 and Wortmannin blocked mesenchymal stem cell attachment in a dose-dependent manner, suggesting a role of phosphatidylinositol 3-kinase in MSC attachment. Our data showed that the growth of PB MSCs could be regulated by interaction with the ECM and that these cells could differentiate into osteoblasts, suggesting their potential for clinical applications.

Isolation and Characterization of Rat Mesenchymal Stem Cells Derived from Granulocyte Colony-Stimulating Factor-Mobilized Peripheral Blood

Mesenchymal stem cells (MSCs) have been isolated from many tissues and organs. However, there is much dispute as to whether MSCs exist in peripheral blood. This may be due to the limited identification methods of MSCs, especially the lack of detection markers for phenotypic characteristics. In this study, as many as 10 surface markers of MSCs derived from rat peripheral blood (rPBMSCs) were analyzed after granulocyte colony-stimulating factor mobilization. Our results suggest that mobilized rPBMSCs overexpress mesenchymal markers, including CD90, CD44, CD29, CD73 and CD105, but do not express CD45, CD11b, CD79a, CD34 or HLA-DR. This is in conformity with the standard definition of MSCs by the International Society for Cellular Therapy. In addition, the colony-forming efficiency of the mobilized rat peripheral blood was 15.83 ± 1.61/106, significantly outnumbering that of the nonmobilized group, which was 0.28 ± 0.1/106 (p < 0.01). Combining the growth characteristics with the differential capacities of mobilized rPBMSCs towards forming osteocytes, chondrocytes and adipocytes, we further confirmed the existence of rPBMSCs. Additionally, this treatment could improve locomotive function after spinal cord injury (SCI) in rats. Due to their convenient collection, fewer complications, cost effectiveness and suitability for autograft, PBMSCs might be a substitute for MSCs derived from bone marrow and provide promising prospects for the cell-based therapy of SCI.