Mesenchymal stem cells (MSCs) are multipotent cells that have been widely used in cell based transplantation therapy. The use of MSCs requires in vitro expansion in order to fulfill their regenerative capacity. Therefore the proliferative ability of MSCs is one of the key factors which determine MSC therapeutic efficacy. In the present study, we showed for the first time that lithium, a well-known antidepressant, reversibly promoted the proliferation of human bone marrow derived MSCs in vitro. MSCs treated with 5 mM lithium proliferated more rapidly than untreated cells without undergoing apoptosis. Lithium increased the proportion of cells in S phase as well as cyclin D1 expression. Mechanistic studies revealed that these effects were dependent upon the activation of the glycogen synthase kinase 3b (GSK-3b) mediated canonical Wnt pathway. Lithium induced Ser9 phosphorylation, which results in the inhibition of GSK-3b activity, b-catenin accumulation and Wnt pathway activation. Utilizing a specific GSK-3b inhibitor SB216763 or siRNA-mediated inhibition of GSK-3b produced effects similar to those induced by lithium. In contrast, either quercetin, an inhibitor of the b-catenin/TCF pathway, or siRNA-mediated knockdown of b-catenin abolished the proliferative effect of lithium, suggesting that lithium stimulates MSC proliferation via the GSK-3b-dependent b-catenin/ Wnt pathway. Collectively, these studies elucidate a novel role of lithium, which may not only provide a simple and effective way to strengthen MSC transplantation therapy efficacy but also shed light on lithium's clinical application for the treatment of certain disorders resulting from b-catenin/ Wnt pathway suppression.

While it has been proved that centrifugal conditions for pure platelet-rich plasma (P-PRP) preparation influence the cellular composition of P-PRP obtained, the optimal centrifugal conditions to prepare P-PRP have not yet been identified. In the present study, platelet-containing plasma (PCP) was prepared with the first-spin of different double-spin methods and P-PRP was prepared with different double-spin methods. Whole-blood analysis was performed to evaluate the cellular composition of PCP and P-PRP. The basal and ADP-induced CD62P expression rates of platelets were assessed by flow cytometry to evaluate the function of platelets in PCP and P-PRP. Enzyme-linked immune sorbent assay was performed to quantify interleukin-1β, tumor necrosis factor-α, platelet-derived growth factor AB and transforming growth factor β1 concentrations of PCP and P-PRP. Correlations between the cellular characteristics and cytokine concentrations of P-PRP were analyzed by Pearson correlation analysis. Effects of P-PRP on the proliferation, survival and migration of human bone marrow-derived mesenchymal stem cells and human articular chondrocytes were evaluated by a Cell Counting Kit-8 assay, live/dead staining and Transwell assay, respectively. The results showed that centrifugation at 160 × g for 10 min and 250 × g for 15 min successively captured and concentrated platelets and growth factors significantly more efficiently with preservation of platelet function compared with other conditions (P<0.05). The correlation analysis showed that the similar leukocyte concentrations and leukocyte-reducing efficiencies resulted in similar pro-inflammatory cytokine concentrations in P-PRP (P>0.05) and the maximization of platelet concentration, platelet enrichment factor, platelet capture efficiency and platelet function resulted in the maximization of growth factor concentrations in P-PRP obtained using the optimal conditions (P<0.05). Compared with P-PRP obtained under other conditions, P-PRP obtained under the optimal conditions significantly promoted the proliferation and migration of cells (P<0.05) and did not alter cell survival (P>0.05). Therefore, centrifugation at 160 × g for 10 min and 250 × g for 15 min successively with removal of the buffy coat as a crucial step may provide an optimal preparation system of P-PRP for clinical application.

Free vascularised fibular grafting has been reported to be successful for adult patients with osteonecrosis of the femoral head (ONFH). However, its benefit in teenage patients with post-traumatic ONFH has not been determined. We evaluated the effectiveness of free vascularised fibular grafting in the treatment of this condition in children and adolescents. We retrospectively analysed 28 hips in 28 patients in whom an osteonecrotic femoral head had been treated with free vascularised fibular grafting between 2002 and 2008. Their mean age was 16.3 years (13 to 19). The stage of the disease at time of surgery, and results of treatment including pre- and post-operative Harris hip scores, were studied. We defined clinical failure as conversion to total hip replacement. All patients were followed up for a mean of four years (2 to 7). The mean Harris hip score improved from 60.4 (37 to 84) pre-operatively to 94.2 (87 to 100) at final follow-up. At the latest follow-up we found improved or unchanged radiographs in all four initially stage II hips and in 23 of 24 stage III or IV hips. Only one hip (stage V) deteriorated. No patient underwent total hip replacement. Free vascularised fibular grafting is indicated for the treatment of post-traumatic ONFH in teenage patients.