Anti-apoptotic effects of adipose-derived adherent stromal cells in mesenchymal stem cells exposed to oxidative stress.

Adipose-derived stromal vascular fractions (SVFs) are a heterogeneous collection of cells, and their regenerative modality has been applied in various animal experiments and clinical trials. Despite the attractive advantages of SVFs in clinical interventions, the recent status of clinical studies involving the application of SVFs in many diseases has not been fully evaluated. Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types despite their low numbers in heart tissue. Here, we sought to determine if SVF implantation into impaired heart tissue affected endogenous MSCs in the heart. Therefore, we investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co-cultured with adipose-derived adherent stromal cells (ADASs) from 6 donors' SVFs under oxidative stress conditions for their roles in many physiological processes in the heart. Interestingly, p53 pathway proteins and mitogen-activated protein kinase (MAPK) signalling pathway components were up-regulated by H2 O2 but exhibited a downward trend in MSCs co-cultured with ADASs. These data suggest that ADASs may inhibit oxidative stress-induced apoptosis in MSCs via the p53 and MAPK pathways. Our findings also suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various responses of MSCs. This finding may provide new insights for the clinical application of adipose-derived SVF transplantation in cardiac diseases. SIGNIFICANCE OF THE STUDY: We investigated the expression levels of proteins associated with oxidation, inflammation, and apoptosis in MSCs co-cultured with isolated ADASs from 6 donors' SVFs under oxidative stress conditions. Our results imply that isolated ADASs from SVFs may inhibit oxidative stress-induced cell cycle arrest and/or apoptosis in MSCs via a p53-dependent pathway. Furthermore, we identified an anti-apoptotic mechanism involving oxidative stress-induced apoptosis by adipose-derived ADASs in MSCs for the first time. Our findings suggest that the positive effects of SVF implantation into damaged heart tissue may be attributed to the various actions of MSCs.

Adipose-Derived Stromal Vascular Fraction Cells: Update on Clinical Utility and Efficacy.

Adipose tissue has emerged as an attractive cell source in tissue engineering and regenerative medicine because it can be easily collected and enriched with stem/progenitor cell populations. The stromal vascular fraction (SVF) derived from adipose tissue contains heterogeneous cell populations such as mesenchymal progenitor/stem cells, preadipocytes, endothelial cells, pericytes, T cells, and M2 macrophages. SVF-derived mesenchymal progenitor/stem cells can be easily expanded in vitro and have the potential to create diverse lineages of cells. Although there have been issues related to their isolation and purification, SVF cells demonstrate regenerative potential in damaged tissues or organs through paracrine and differentiation mechanisms. Furthermore, SVF cells augment immunological tolerance by promoting inhibitory macrophages and T regulatory cells and by decreasing ongoing inflammation. Numerous implantations of freshly isolated, autologous adipose tissue-derived SVF cells in cosmetic surgeries and in a wide variety of other specialties support the safety of SVF cells and have accelerated their clinical application. Despite these attractive advantages of SVF cells in clinical interventions, to our knowledge the recent status of clinical studies of various diseases has not been fully investigated. Therefore this article describes recent advances in the clinical use of SVF cells, as well as the associated challenges and future directions for this field of research. We also speculate that verification of the efficacy and safety of SVF cells requires more basic experimental research, using a standard isolation protocol, and larger randomized clinical trials of the utility of SVF cells in various diseases.

Tanshinone IIA suppresses inflammatory bone loss by inhibiting the synthesis of prostaglandin E2 in osteoblasts.

Tanshinone IIA isolated from Danshen is widely used in Oriental medicine. However, the action of tanshinone IIA in inflammatory bone-resorptive diseases remains unknown. Here we examined the effect of tanshinone IIA in inflammation-mediated osteoclastic bone resorption. Tanshinone IIA inhibited osteoclast differentiation in cocultures of bone marrow cells and calvarial osteoblasts. Tanshinone IIA regulated the expression of receptor activator of NF-kappaB ligand and osteoprotegerin in osteoblasts treated with lipopolysaccharide (LPS). Also, tanshinone IIA inhibited prostaglandin E(2) (PGE(2)) synthesis by inhibiting Cyclooxygenase-2 (COX-2) expression induced by LPS. Furthermore, tanshinone IIA greatly suppressed bone loss in the mouse models of bone loss. Our findings suggest that tanshinone IIA inhibits osteoclast formation by inhibiting COX-2/PGE(2) signaling and by suppressing bone erosion in vivo. These results suggest that tanshinone IIA may be of therapeutic value as an anti-bone-resorptive drug in the treatment of bone-related disease.

AG490, a Jak2-specific inhibitor, induces osteoclast survival by activating the Akt and ERK signaling pathways.

Osteoclasts are multinucleated cells with the unique ability to resorb bone. Elevated activity of these cells under pathologic conditions leads to the progression of bone erosion that occurs in osteoporosis, periodontal disease, and rheumatoid arthritis. Thus, the regulation of osteoclast apoptosis is important for bone homeostasis. In this study, we examined the effects of the Janus tyrosine kinase 2 specific inhibitor AG490 on osteoclast apoptosis. We found that AG490 greatly inhibited osteoclast apoptosis. AG490 stimulated the phosphorylation of Akt and ERK. Adenovirus-mediated expression of dominant negative (DN)-Akt and DN-Ras in osteoclasts inhibited the survival of osteoclasts despite the presence of AG490. Cytochrome c release during osteoclast apoptosis was inhibited by AG490 treatment, but this effect was inhibited in the presence of LY294002 or U0126. AG490 suppressed the proapoptotic proteins Bad and Bim, which was inhibited in osteoclasts infected with DN-Akt and DN-Ras adenovirus. In addition, constitutively active MEK and myristoylated-Akt adenovirus suppressed the cleavage of pro-caspase-9 and -3 and inhibited osteoclast apoptosis induced by etoposide. Taken together, our results suggest that AG490 inhibited cytochrome c release into the cytosol at least partly by inhibiting the pro-apoptotic proteins Bad and Bim, which in turn suppressed caspase-9 and -3 activation, thereby inhibiting osteoclast apoptosis.