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.

Chondrogenesis of periodontal ligament stem cells by transforming growth factor-β3 and bone morphogenetic protein-6 in a normal healthy impacted third molar / 国际口腔科学杂志·英文版

The periodontal ligament-derived mesenchymal stem cell is regarded as a source of adult stem cells due to its multipotency. However, the proof of chondrogenic potential of the cells is scarce. Therefore, we investigated the chondrogenic differentiation capacity of periodontal ligament derived mesenchymal stem cells induced by transforming growth factor (TGF)-β3 and bone morphogenetic protein (BMP)-6. After isolation of periodontal ligament stem cells (PDLSCs) from human periodontal ligament, the cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with 20% fetal bovine serum (FBS). A mechanical force initiated chondrogenic differentiation of the cells. For chondrogenic differentiation, 10 µg·L⁻¹ TGF-β3 or 100 µg∙L⁻¹ BMP-6 and the combination treating group for synergistic effect of the growth factors. We analyzed the PDLSCs by fluorescence-activated cell sorting and chondrogenesis were evaluated by glycosaminoglycans assay, histology, immunohistochemistry and genetic analysis. PDLSCs showed mesenchymal stem cell properties proved by FACS analysis. Glycosaminoglycans contents were increased 217% by TGF-β3 and 220% by BMP-6. The synergetic effect of TGF-β3 and BMP-6 were shown up to 281% compared to control. The combination treatment increased Sox9, aggrecan and collagen II expression compared with not only controls, but also TGF-β3 or BMP-6 single treatment dramatically. The histological analysis also indicated the chondrogenic differentiation of PDLSCs in our conditions. The results of the present study demonstrate the potential of the dental stem cell as a valuable cell source for chondrogenesis, which may be applicable for regeneration of cartilage and bone fracture in the field of cell therapy.

Blood Vessel Regeneration using Human Umbilical Cord-derived Endothelial Progenitor Cells in Cyclophosphamide-treated Immune-deficient Mice

Endothelial cells are a vital constituent of most mammalian organs and are required to maintain the integrity of these tissues. These cells also play a major role in angiogenesis, inflammatory reactions, and in the regulation of thrombosis. Angiogenesis facilitates pulp formation and produces the vessels which are essential for the maintenance of tooth homeostasis. These vessels can also be used in bone and tissue regeneration, and in surgical procedures to place implants or to remove cancerous tissue. Furthermore, endothelial cell regeneration is the most critical component of the tooth generation process. The aim of the present study was to stimulate endothelial regeneration at a site of acute cyclophosphamide (CP)-induced endothelial injury by treatment with human umbilical cord-derived endothelial/mesenchymal stem cells (hEPCs). We randomly assigned 16 to 20-week-old female NOD/SCID mice into three separate groups, a hEPC (1 x 10(5) cells) transplanted, 300mg/kg CP treated and saline (control) group. The mice were sacrificed on days 5 and 10 and blood was collected via the abdominal aorta for analysis. The alanine transaminase (ALT), aspartate aminotransferase (AST), serum alkaline phosphatase (s-ALP), and albumin (ALB) levels were then evaluated. Tissue sections from the livers and kidneys were stained with hematoxylin and eosin (HE) for microscopic analysis and were subjected to immunohistochemistry to evaluate any changes in the endothelial layer. CP treatment caused a weight reduction after one day. The kidney/body weight ratio increased in the hEPC treated animals compared with the CP only group at 10 days. Moreover, hEPC treatment resulted in reduced s-ALP, AST, ALT levels compared with the CP only group at 10 days. The CP only animals further showed endothelial injuries at five days which were recovered by hEPC treatment at 10 days. The number of CD31-positive cells was increased by hEPC treatment at both 5 and 10 days. In conclusion, the CP-induced disruption of endothelial cells is recovered by hEPC treatment, indicating that hEPC transplantation has potential benefits in the treatment of endothelial damage.