Differentiation of human adipose-derived stem cells induced by recombinantly expressed fibroblast growth factor 10 in vitro and in vivo

New Bioink Derived from Neonatal Chicken Bone Marrow Cells and Its 3D-Bioprinted Niche for Osteogenic Stimulators

This study examined whether neonatal chicken bone marrow cells (cBMCs) could support the osteogenesis of human stromal cells in a three-dimensional (3D) extracellular bioprinting niche. The majority (>95%) of 4-day-old cBMCs subcultured 5 times were positive for osteochondrogenesis-related genes (Col I, Col II, Col X, aggrecan, Sox9, osterix, Bmp2, osteocalcin, Runx2, and osteopontin) and their related proteins (Sox9, collagen type I, and collagen type II). LC-MS/MS analysis demonstrated that cBMC-conditioned medium (c-medium) contained proteins related to bone regeneration, such as periostin and members of the TGF-β family. Next, a significant increase in osteogenesis was detected in three human adipose tissue-derived stromal cell (hASC) lines, after exposure to c-medium concentrates in 2D culture (p < 0.05). To evaluate biological function in a 3D environment, we employed the cBMC-derived bioactive components as a cell-supporting biomaterial in collagen bioink, which was printed to construct a 3D hASC-laden scaffold for observing osteogenesis. Complete osteogenesis was detected in vitro. Moreover, after transplantation of the hASC-laden structure into rats, prominent bone formation was observed compared with that in control rats receiving scaffold-free hASC transplantation. These results demonstrated that substance(s) secreted by chick bone marrow cells clearly activated the osteogenesis of hASCs in 2D- or 3D-niches.

A Novel Approach to Septal Perforation Repair: Septal Cartilage Cells Induce Chondrogenesis of hASCs In Vitro

The aim of this study was to investigate the effect of medium harvested from septal cartilage cells on chondrogenic differentiation of adipose stem cells (hASCs) and to compare/contrast its properties to those of a commonly used standard medium formulation in terms of induction and maintenance of chondrogenic hASCs. Differentiation was carried out under three different conditions: septal cartilage medium-SCM, chondrogenic differentiation medium-CM, and 50:50 mixture of CM/SCM. Mesenchymal stem cells (MSCs) markers were determined by flow cytometry. The cytotoxic and apoptotic effects were determined by MTS and Annexin V assay, respectively. The differentiation status of the cells was confirmed by Alcian blue staining, and quantitative real-time flow cytometry showed that hASCs were positive for MSCs, negative for hematopoietic stem cells and endothelial cell surface markers. According to MTS analysis, the first condition was not toxic at any concentration tested. Annexin V assay revealed that the application of different concentrations of SCM did not result in any cell death. The Alcian blue and gene expression analyses showed that the cells in the SCM group underwent the highest cartilage cell formation. The observed increase in chondrogenesis may offer better treatment options for the cartilage defects seen in nasal septum perforation.

Protective effects of keratinocyte growth factor-2 on ischemia-reperfusion-induced lung injury in rats

Ischemia-reperfusion (I/R) is a common cause to compromise tissue injury via endothelial and epithelial barrier dysfunction and damage. Keratinocyte growth factor (KGF)-2 could play an important role in the repair of alveolar epithelial damage and maintain the capillary barrier function. The present study aimed to investigate the potential effects of KGF-2 on I/R-induced lung injury in rats and the related mechanisms. KGF-2 (2.5-10 mg/kg) was administered intratracheally in rats 3 days before the left lobe with ischemia for 60 minutes followed by reperfusion for 180 minutes. Lung injury was evaluated by measuring lung morphology, blood gas analysis, total cell number, and protein concentration in the bronchoalveolar lavage fluid. The protective effects of KGF-2 on human pulmonary microvascular endothelial cells and related mechanisms were evaluated. Pretreatment with KGF-2 significantly prevented I/R-induced lung edema, inflammatory cell infiltration, protein exudation, and the release of inflammatory cytokines in rats, or I/R-induced endothelial cell apoptosis, migration, and barrier dysfunction. Phosphoinositide 3-kinase or epidermal growth factor receptor inhibitors attenuated the protective effect of KGF-2 in endothelial cells. Our results evidence that the local administration of KGF-2 may be an alternative to prophylactic or adjunct drug therapies for I/R-induced lung injury.

Effects of continuous passage on immunomodulatory properties of human adipose-derived stem cells

Human adipose-derived stem cells (hADSCs) have the ability to influence immune response, and hence are key cell sources for tissue repair and regeneration. In this study we explored the effect of continuous passage on the immunomodulatory properties of hADSCs to provide some advises for large-scale production of hADSCs for clinical applications. We found that after continuous passage, the specific surface markers expression levels as well as the adipogenic and osteogenic differentiation capacities of hADSCs had no obvious changes. However, the secretion levels of IL-10 and HGF reduced dramatically along with passage numbers. Furthermore, the INF-γ level was found higher in which medium peripheral blood mononuclear cells were co-cultured with hADSCs with higher passage numbers. Also, the in vivo experiments showed that the peritonitis model mice, which were injected with higher passage numbers of hADSCs, tended to have higher levels of inflammation. All these together indicated that continuous passage has only minor effect on the cell phenotypes but will impair the immunomodulatory properties of hADSCs. This suggests that hADSCs could be prepared by continuous passage, but only those cells of lower passage numbers would be ideal therapeutic tools.

Defining vascular stem cells

Mesenchymal stem cells (MSCs) exist in most adult tissues and have been located near or within blood vessels. Although "perivascular" has been commonly used to describe such locations, increasing evidence points at the vessel wall as the exact location. Thus, "vascular stem cells (VSCs)" is recommended as a more accurate term for MSCs. Furthermore, 2 cell populations, namely pericytes and adventitial progenitor cells (APCs), are the likely VSCs. The pericyte evidence relies on the so-called pericyte-specific markers, but none of these markers is pericyte specific. In addition, pericytes appear to be too functionally diverse and sophisticated to have a large differentiation capacity. On the other hand, APCs are more naïve functionally and, therefore, more akin to being VSCs. In vitro, these cells spontaneously differentiate into pericytes, and can be induced to differentiate into vascular cells (endothelial and smooth muscle cells) and mesenchymal cells (e.g., bone, cartilage, and fat). In vivo, indirect evidence also points to their ability to differentiate into mesenchymal cells of their native tissue (e.g., fat). Moreover, they possess a large paracrine capacity and, therefore, can help maintain tissue homeostasis by encouraging the replication and differentiation of mesenchymal cells locally. These proposed in vivo functions are areas of interest for future research on VSCs.

Potential clinical application of KGF-2 (FGF-10) for acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an acute life-threatening form of hypoxemic respiratory failure with a high mortality rate, and there is still a great need for more effective therapies for such a severe and lethal disease. Dysfunction of endothelial and epithelial barriers is one of the most important mechanisms in hypoxia-associated ALI/ARDS. The acceleration of the epithelial repair process in the injured lung may provide an effective therapeutic target. KGF-2, a potent alveolar epithelial cell mitogen, plays an important role in organ morphogenesis and epithelial differentiation, and modulates a variety of mechanisms recognized to be important in alveolar repair and resolution in ALI/ARDS. Preclinical and clinical studies have suggested that KGF-2 may be the candidate of novel therapies for alveolar epithelial damage during ALI/ARDS.

Different regulation role of myostatin in differentiating pig ADSCs and MSCs into adipocytes

Myostation (MSTN), which is primarily expressed in muscle, plays an important role in myogenic and adipogenic cells. However, there is little information about whether MSTN displays different roles between adipose-derived stem cells (ADSCs) and muscle satellite cells (MSCs). The two kinds of cells can both exist in the muscle and differentiate into adiposities. In this research, we isolated ADSCs and MSCs from porcine fat tissues and semitendinosus muscle, respectively, to investigate the effect of MSTN on the adipogenesis of those cells. ADSCs and MSCs were treated with recombinant human MSTN during the induction of adipogenesis or before the induction of differentiation. Then, we evaluated adipogenesis by Oil Red O staining and assessed the expression patterns of adipocyte-specific fatty acid binding protein (aP2) and peroxisome proliferator-activated receptor (PPAR) γ using real-time polymerase chain reaction methods. Our results indicated that the treatment with MSTN before or during the induction of differentiation in MSCs could both inhibit the adipogenesis. However, the treatment with MSTN only during the induction of differentiation in ADSCs could suppress the adipogenesis. Those results showed that MSTN had different roles in the adipogenesis of ADSCs and MSCs. It can shed new light on the origin of adipocyte located in muscle.