Therapeutic and regenerative potential of different sources of mesenchymal stem cells for cardiovascular diseases

Mesenchymalstemcells(MSCs)areidealcandidatesfortreatingmanycardiovasculardiseases.MSCscanmodify the internal cardiac microenvironment to facilitate their immunomodulatory and differentiation abilities,which are essential to restore heart function.MSCs can be easily isolated from different sources,including bone marrow,adipose tissues,umbilical cord,and dental pulp.MSCs from various sources differ in their regenerative and therapeutic abilities for cardiovascular disorders.In this review,we will summarize the therapeutic potential of each MSC source for heart diseases and highlight the possible molecular mechanisms of each source to restore cardiac function.

Liver regeneration using decellularized splenic scaffold: a novel approach in tissue engineering

BACKGROUND： The potential application of decellularized liver scaffold for liver regeneration is limited by severe shortage of donor organs. Attempt of using heterograft scaffold is accompanied with high risks of zoonosis and immunological rejection. We proposed that the spleen, which procured more extensively than the liver, could be an ideal source of decellularized scaffold for liver regeneration. METHODS： After harvested from donor rat, the spleen was processed by 12-hour freezing/thawing ×2 cycles, then circulation perfusion of 0.02% trypsin and 3% Triton X-100 sequentially through the splenic artery for 32 hours in total to prepare decellularized scaffold. The structure and component characteristics of the scaffold were determined by hematoxylin and eosin and immumohistochemical staining, scanning electron microscope, DNA detection, porosity measurement, biocompatibility and cytocompatibility test. Recellularization of scaffold by 5×106 bone marrow mesenchymal stem cells（BMSCs） was carried out to preliminarily evaluate the feasibility of liver regeneration by BMSCs reseeding and differentiation in decellularized splenic scaffold.RESULTS： After decellularization, a translucent scaffold, which retained the gross shape of the spleen, was generated. Histological evaluation and residual DNA quantitation revealed the remaining of extracellular matrix without nucleus and cytoplasm residue. Immunohistochemical study proved the existence of collagens I, IV, fibronectin, laminin and elastin in decellularized splenic scaffold, which showed a similarity with decellularized liver. A scanning electron microscope presented the remaining three-dimensional porous structure of extracellular matrix and small blood vessels. The poros-ity of scaffold, aperture of 45.36±4.87 μm and pore rate of 80.14%±2.99% was suitable for cell engraftment. Subcutaneous implantation of decellularized scaffold presented good histocompatibility, and recellularization of the splenic scaffold demonstrated that BMSCs could locate and survive in the decellularized matrix. CONCLUSION： Considering the more extensive organ source and satisfying biocompatibility, the present study indicated that the three-dimensional decellularized splenic scaffold might have considerable potential for liver regeneration when combined with BMSCs reseeding and differentiation.

Mandibular Embryonal Rhabdomyosarcoma Confused with a Vascular Malformation: About a Case

Malignant mesenchymal tumors (MTM) in children represent 5% to 10% of malignant tumors in children. They constitute a heterogeneous group of tumors of various differentiations depending on their supposed tissue of origin. They mainly include tumors of muscular origin, those derived from connective, vascular, nervous, or adipose tissue. Rhabdomyosarcoma (RMS) is the most common mesenchymal tumor in children and adolescents (60% to 70% of them). And it accounts for 5.8% of all malignant solid tumors in children. Almost half of rhabdomyosarcomas occur in the head and neck. The prognosis for this type of tumor is particularly poor. A case of rhabdomyosarcoma in the mandible with extension to the abdominal wall and unilateral testis in a 6-month-old infant is reported with evolution since birth. It is a purplish lesion at the level under the right chin which was initially taken for vascular malformation, evolving very quickly towards a mandibular mass deforming the painful face with inflammatory signs, followed by the appearance of a hard swelling under the skin on the left flank taking on the same aspect of the mandibular mass. This observation illustrates the need to know how to systematically think about tumor causes in the face of atypical aspects and to carry out an anatomopathological examination.

Tethering of Gly-Arg-Gly-Asp-Ser-Pro-Lys Peptides on Mg-Doped Hydroxyapatite

Stem cell homing, namely the recruitment of mesenchymal stem cells （MSCs） to injured tissues, is highly effective for bone regeneration in vivo. In order to explore whether the incorporation of mimetic peptide sequences on magnesium-doped （Mg-doped） hydroxyapatite （HA） may regulate the homing of MSCs, and thus induce cell migration to a specific site, we covalently functionalized MgHA disks with two chemotactic/haptotactic factors： either the fibronectin fragment III1-C human （FF III1-C）, or the peptide sequence Gly-Arg-Gly-Asp-Ser-Pro-Lys, a fibronectin analog that is able to bind to integrin trans- membrane receptors. Preliminary biological evaluation of MSC viability, analyzed by 3-（4,5-dimethyl- thiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） test, suggested that stem cells migrate to the MgHA disks in resoonse to the grafted haototaxis stimuli.

Enhanced critical-sized bone defect repair efficiency by combining deproteinized antler cancellous bone and autologous BMSCs

Previously we have demonstrated that calcinated antler cancellous bone（CACB） has great potential for bone defect repair,due to its highly similar composition and architecture to natural extracellular bone matrix.This study is aiming at seeking for an optimal strategy of combined application of CACB and bone marrow mesenchymal stem cells（BMSCs） in bone defect repair.In vitro study demonstrated that CACB promoted the adhesion,spreading and viability of BMSCs.Increased extracellular matrix production and expression of osteogenic markers in BMSCs were observed when seeded on CACB scaffolds.The cells ceased to proliferation in the dual effect of CACB and osteogenic induction at the early stage of incubation.Hence synergistic effect of CACB combined with autologous undifferentiated BMSCs in rabbit mandible critical-sized defect repair was further evaluated.Histological analysis results showed that loading the CACB with autologous BMSCs resulted in enhanced new bone formation and angiogenesis when compared with implanted CACB alone.These findings indicate that the combination of CACB and autologous BMSCs should become potential routes to improve bone repair efficiency