Platelet-Derived Growth Factor-BB Priming Enhances Vasculogenic Capacity of Bone Marrow-Derived Endothelial Precursor Like Cells

BACKGROUND@#Human endothelial progenitor cells (EPCs) were first identified in the peripheral blood and later in the cord blood and bone marrow (BM) with different vascularization capacity and different surface marker profiles. However, their identity and functional roles in neovascularization have not been clearly demonstrated in vivo and in vitro. @*METHODS@#Characterization of BM-EPC like cells were performed by fluorescence-activated cell sorting, immunofluorescence staining, enzyme-linked immunosorbent assay, Matrigel tube formation assay, and western blot analysis. @*RESULTS@#BM-EPC like cells were identified by selective adhesion to fibronectin and collagen from BM mononuclear cells, which generate fast-growing colonies with spindle morphology, express surface markers of CD105, vWF, UEA-I lectin binding, secrete HGF, VEGF, TGF-beta1 but can be distinguished from circulating EPC and endothelial cells by no expression of surface markers such as CD31, CD309, CD45, and CD34. These BM-EPC like cells shared many cell surface markers of BM-mesenchymal stem cells (MSC) but also can be distinguished by their vasculogenic property and other unique surface markers. Furthermore, the vasculogenic capacity of BM-EPC like cells were enhanced by co-culture of BMMSC or PDGF-BB priming. PDGF-BB stimulated cell migration, proliferation, and secretion of laminin b-1, which was proposed as one of the mechanisms involved in the better vascularization of BM-EPC like cells. @*CONCLUSION@#PDGF-BB priming may be applied to improve the potency and function of BM-EPC like cells as vasculogenic cell therapy for the ischemic vascular repair.

A Pathophysiological Validation of Collagenase II-Induced Biochemical Osteoarthritis Animal Model in Rabbit

BACKGROUND: Current dilemma working with surgically-induced OA (osteoarthritis) model include inconsistent pathological state due to various influence from surrounding tissues. On the contrary, biochemical induction of OA using collagenase II has several advantageous points in a sense that it does not involve surgery to induce model and the extent of induced cartilage degeneration is almost uniform. However, concerns still exists because biochemical OA model induce abrupt destruction of cartilage tissues through enzymatic digestion in a short period of time, and this might accompany systemic inflammatory response, which is rather a trait of RA (rheumatoid arthritis) than being a trait of OA. METHODS: To clear the concern about the systemic inflammatory response that might be caused by abrupt destruction of cartilage tissue, OA was induced to only one leg of an animal and the other leg was examined to confirm the presence of systemic degenerative effect. RESULTS: Although the cartilage tissues were rapidly degenerated during short period of time upon biochemical induction of OA, they did not accompanied with RA-like process based on the histology data showing degeneration of articular cartilage occurred only in the collagenase-injected knee joint. Scoring evaluation data indicated that the cartilage tissues in non-induced joint remained intact. Neutrophil count transiently increase between day 8 and day 16, and there were no significant change in other complete blood count profile showing a characteristics of OA disease. CONCLUSION: These study shows that biochemically induced cartilage degeneration truly represented uniform and reliable OA state.

Correction to: Endogenous Stem Cells in Homeostasis and Aging

In the previous version of this article, two important references [47-2, 173] were missing. The authors would like to make corrections in the original version of the article.

Recent Advances in Stem Cell Researches and Their Future Perspectives in Regenerative Medicine

No abstract available.

Endogenous Stem Cells in Homeostasis and Aging

In almost all human tissues and organs, adult stem cells or tissue stem cells are present in a unique location, the so-called stem cell niche or its equivalent, continuously replenishing functional differentiated cells. Those endogenous stem cells can be expanded for cell therapeutics using ex vivo cell culture or recalled for tissue repair in situ through cell trafficking and homing. In the aging process, inefficiency in the endogenous stem cell-mediated healing mechanism can emerge from a variety of impairments that accumulate in the processes of stem cell self-renewal, function, differentiation capacity, and trafficking through cell autonomous intrinsic pathways (such as epigenetic alterations) or systemic extrinsic pathways. This review examines the homeostasis of endogenous stem cells, particularly bone marrow stem cells, and their dysregulation in disease and aging and discusses possible intervention strategies. Several systemic pro-aging and rejuvenating factors, recognized in heterochronic parabiosis or premature aging progeroid animal models, are reviewed as possible anti-aging pharmaceutical targets from the perspective of a healthy environment for endogenous stem cells. A variety of epigenetic modifications and chromosome architectures are reviewed as an intrinsic cellular pathway for aging and senescence. A gradual increase in inflammatory burden during aging is also reviewed. Finally, the tissue repair and anti-aging effects of Substance-P, a peptide stimulating stem cell trafficking from the bone marrow and modifying the inflammatory response, are discussed as a future anti-aging target.

Low-Dose Ionizing γ-Radiation Promotes Proliferation of Human Mesenchymal Stem Cells and Maintains Their Stem Cell Characteristics

Mesenchymal stem cells (MSCs), which are multipotent and have self-renewal ability, support the regeneration of damaged normal tissue. A number of external stimuli promote migration of MSCs into peripheral blood and support their participation inwound healing. In an attempt to harness the potential beneficial effects of such external stimuli, we exposed human MSCs (hMSCs) to one such stimulus-low-dose ionizing radiation (LDIR)-and examined their biological properties. To this end, we evaluated differences in proliferation, cell cycle, DNA damage, expression of surface markers (CD29, CD34, CD90, and CD105), and differentiation potential ofhMSCs before and after irradiation with γ-rays generated using a ¹³⁷ CSirradiator.At doses less than 50 mGy, LDIR had no significant effect on the viability or apoptosis of hMSCs. Interestingly, 10 mGyofLDIR increased hMSC viability by 8% (p<0.001) comparedwith non-irradiatedhMSCs.At doses less than 50 mGy, LDIR did not induceDNA damage, including DNA strand breaks, or cause cellular senescence or cell-cycle arrest. Surface marker expression and in vitro differentiation potential of hMSCs were maintained after two exposures to LDIR at 10 mGy per dose. In conclusion, a two-dose exposure to LDIR at 10 mGy per dose not only facilitates proliferation of hMSCs, it alsomaintains the stem cell characteristics of hMSCswithout affecting their viability.These results provide evidence for the potential ofLDIRas an external stimulus for in vitro expansion of hMSCs and application in tissue engineering and regenerative medicine.

Intravenous Administration of Substance P Attenuates Mechanical Allodynia Following Nerve Injury by Regulating Neuropathic Pain-Related Factors

This study aimed to investigate the analgesic effect of substance P (SP) in an animal model of neuropathic pain. An experimental model of neuropathic pain, the chronic constriction injury (CCI) model, was established using ICR mice. An intravenous (i.v.) injection of SP (1 nmole/kg) was administered to the mice to examine the analgesic effects of systemic SP on neuropathic pain. Behavioral testing and immunostaining was performed following treatment of the CCI model with SP. SP attenuated mechanical allodynia in a time-dependent manner, beginning at 1 h following administration, peaking at 1 day post-injection, and decaying by 3 days post-injection. The second injection of SP also increased the threshold of mechanical allodynia, with the effects peaking on day 1 and decaying by day 3. A reduction in phospho-ERK and glial fibrillary acidic protein (GFAP) accompanied the attenuation of mechanical allodynia. We have shown for the first time that i.v. administration of substance P attenuated mechanical allodynia in the maintenance phase of neuropathic pain using von Frey’s test, and simultaneously reduced levels of phospho-ERK and GFAP, which are representative biochemical markers of neuropathic pain. Importantly, glial cells in the dorsal horn of the spinal cord (L4–L5) of SP-treated CCI mice, expressed the anti-inflammatory cytokine, IL-10, which was not seen in vehicle saline-treated mice. Thus, i.v. administration of substance P may be beneficial for improving the treatment of patients with neuropathic pain, since it decreases the activity of nociceptive factors and increases the expression of anti-nociceptive factors.

Disc-Type Hyaline Cartilage Reconstruction Using 3D-Cell Sheet Culture of Human Bone Marrow Stromal Cells and Human Costal Chondrocytes and Maintenance of Its Shape and Phenotype after Transplantation

In this study, we developed the disc-type bio-cartilage reconstruction strategies for transplantable hyaline cartilage for reconstructive surgery using 3D-cell sheet culture of human bone marrow stromal cells and human costal chondrocytes. We compared chondrogenesis efficiency between different chondrogenic-induction methods such as micromass culture, pellet culture, and 3D-cell sheet culture. Among them, the 3D-cell sheet culture resulted in the best chondrogenesis with the disc-type bio-cartilage (>12 mm diameter in size) in vitro, but sometimes spontaneous curling and contraction of 3D-cell sheet culture resulted in the formation of bead-type cartilage, which was prevented by type I collagen coating or by culturing on amniotic membrane. Previously, it was reported that tissue-engineered cartilage reconstructed in vitro does not maintain its cartilage phenotype after transplantation but tends to transform to other tissue type such as bone or connective tissue. However, the disc-type bio-cartilage of 3D-cell sheet culture maintained its hyaline cartilage phenotype even after exposure to the osteogenic-induction condition in vitro for 3 weeks or after the transplantation for 4 weeks in mouse subcutaneous. Collectively, the disc-type bio-cartilage with 12 mm diameter can be reproducibly reconstructed by the 3D-cell sheet culture, whose hyaline cartilage phenotype and shape can be maintained under the osteogenic-induction condition as well as after the transplantation. This disc-type bio-cartilage can be proposed for the application to reconstructive surgery and repair of disc-type cartilage such as mandibular cartilage and digits.