Hong-Tian Zhang

Linear Ordered Collagen Scaffolds Loaded with Collagen-Binding Neurotrophin-3 Promote Axonal Regeneration and Partial Functional Recovery after Complete Spinal Cord Transection

Neurotrophin-3 (NT3) is an important neurotrophic factor for spinal cord injury (SCI) repair. However, constant exchange of cerebrospinal fluid often decreases the effective dosage of NT3 at the targeted injury site. In the present study, a recombinant collagen-binding NT3 (CBD-NT3), consisting of a collagen-binding domain (CBD) and native NT3, was constructed. Linear rat-tail collagen (LRTC) was used as a physical carrier for CBD-NT3 to construct a LRTC/C3 system. The collagen-binding ability of CBD-NT3 was verified, and the bioactivity of CBD-NT3 was assayed with neurite outgrowth of dorsal root ganglia (DRG) explants and DRG cells in vitro. After complete spinal cord transection in rats, LRTC/CBD-NT3 or the LRTC/NT3 system was transplanted into the injury site. Hindlimb locomotion recovery was closely observed using the Basso-Beattie-Bresnahan (BBB) locomotor rating scale and the grid walk test. Significant improvement was observed in the LRTC/CBD-NT3 group. The results of regenerating nerve fiber and anterograde tracing of biotinylated dextran amine (BDA)-labeled corticospinal tract (CST) fibers demonstrated axonal regeneration of LRTC/CBD-NT3 in the injured spinal cord. Serotonin fiber regrowth also illustrated the effectiveness of LRTC/CBD-NT3. Thus, collagen-binding NT3 with LRTC may provide an effective method for treating SCI.

Functional endothelial progenitor cells derived from adipose tissue show beneficial effect on cell therapy of traumatic brain injury

Endothelial progenitor cells (EPCs) are responsible for postnatal vasculogenesis in physiological and pathological neovascularization. Adipose tissue (AT) is an abundant source of mesenchymal stem cells (MSCs), which have multipotent differentiation ability. We successfully derived EPCs from AT, which maintained a strong proliferative capacity and demonstrated the characteristic endothelial function of uptaking of acetylated low-density lipoprotein. They formed tube-like structures in vitro. Endothelial nitric oxide synthase (eNOS) gene expression in EPCs was similar to that in mature endothelial cells. Transplantation of EPCs derived from AT after the acute phase was applied in rats with traumatic brain injury (TBI). Transplanted EPCs participated in the neovascularization of injured brain. Improving functional recovery, reducement of deficiency volume of brain, host astrogliosis and inflammation were found. These results suggest that adult AT derived stem cells can be induced to functional EPCs and have beneficial effect on cell therapy.

Neural differentiation ability of mesenchymal stromal cells from bone marrow and adipose tissue: a comparative study

BACKGROUND AIMS The characteristics, such as morphologic and phenotypic characteristics and neural transdifferentiation ability, of mesenchymal stromal cells (MSC) derived from different origins have yet to be reported for cases isolated from the same individual. METHODS The proliferation capacity, secretion ability of neurotrophins (NT) and neural differentiation ability in rat MSC isolated from bone marrow (BMSC) and adipose tissue (ADSC) were compared from the same animal. RESULTS The ADSC had a significantly higher proliferation capacity than BMSC according to cell cycle and cumulative population doubling analyses. The proportion of cells expressing neural markers was greater in differentiated ADSC than in differentiated BMSC. Furthermore, the single neurosphere derived from ADSC showed stronger expansion and differentiation abilities than that derived from BMSC. The findings from Western blot lent further support to the immunocytochemical data. The mRNA and protein levels of nerve growth factor (NGF) and brain-derived growth factor (BDNF) expressed in ADSC were significantly higher than those in BMSC at different stages before and following induction. CONCLUSIONS Our study suggests that the proliferation ability of ADSC is superior to that of BMSC. Furthermore, differentiated ADSC expressed higher percentages of neural markers. As one possible alternative source of BMSC, ADSC may have wide potential for treating central nervous system (CNS) diseases.

Human Wharton’s jelly cells can be induced to differentiate into growth factor-secreting oligodendrocyte progenitor-like cells

Human Whartons jelly-derived mesenchymal stromal cells (hWJ-MSCs) are capable of differentiating into neural and astroglia-like cell types. However, a reliable means of inducing the selective differentiation of hWJ-MSCs into oligodendrocyte progenitor cells (OPCs) in vitro has not yet been established. In this study, the OPC-like differentiation of hWJ-MSCs was characterized using and immunoblotting. The hWJ-MSC-derived OPC-like cells were able to secrete nerve growth factors and promote neurite outgrowth in vitro. These results show that hWJ-MSCs can be induced to differentiate into cells with the morphologic, phenotypic and functional characteristics of OPC-like cells.

Comparison of the Efficiencies of Three Neural Induction Protocols in Human Adipose Stromal Cells

The aim of this study was to compare the neural differentiation potential and the expression of neurotrophic factors (NTFs) in differentiated adipose-derived stem cells (ADSCs) using three established induction protocols, serum free (Protocol 1), chemical reagents (Protocol 2), and spontaneous (Protocol 3) protocols. Protocol 1 produced the highest percentage of mature neural-like cells (MAP2ab+). Protocol 2 showed the highest percentage of immature neural-like cells (β-tubulin III+), but the neural-like state was transient and reversible. Protocol 3 caused ADSCs to differentiate spontaneously into immature neural-like cells, but not into mature neural cell types. The neural-like cells produced by Protocol 1 lived the longest in culture with little cell death, but Protocol 2 and 3 led to the significant cell death. Therefore, Protocol 1 is the most efficient among these protocols. Additionally, soon after differentiation, the mRNA levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in dADSCs were sharply decreased by Protocol 1 and 2 (acute induction protocol), but not by Protocol 3 (chronic induction protocol). The results indicate that NTFs played an important role in neural differentiation via acute responses to NGF and BDNF, but not chronically during the transdifferentiation process.

Neural stem-like cells derived from human amnion tissue are effective in treating traumatic brain injury in rat.

Although human amnion derived mesenchymal stem cells (AMSC) are a promising source of stem cells, their therapeutic potential for traumatic brain injury (TBI) has not been widely investigated. In this study, we evaluated the therapeutic potential of AMSC using a rat TBI model. AMSC were isolated from human amniotic membrane and characterized by flow cytometry. After induction, AMSC differentiated in vitro into neural stem-like cells (AM-NSC) that expressed higher levels of the neural stem cell markers, nestin, sox2 and musashi, in comparison to undifferentiated AMSC. Interestingly, the neurotrophic factors, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin 3 (NT-3), glial cell derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF) were markedly upregulated after neural stem cell induction. Following transplantation in a rat TBI model, significant improvements in neurological function, brain tissue morphology, and higher levels of BDNF, NGF, NT-3, GDNF and CNTF, were observed in the AM-NSC group compared with the AMSC and Matrigel groups. However, few grafted cells survived with minimal differentiation into neural-like cells. Together, our results suggest that transplantation of AM-NSC promotes functional rehabilitation of rats with TBI, with enhanced expression of neurotrophic factors a likely mechanistic pathway.

Comparison of adult neurospheres derived from different origins for treatment of rat spinal cord injury

This study is designed to evaluate the therapeutic effects of three types of neurospheres (NSs) derived from brain, bone marrow and adipose tissue in a rat model of spinal contusive injury. As shown by BBB locomotor rating scale and grid test, the optimal therapeutic responses generated by subventricular zone-derived NSs (SVZ-NSs), and followed by adipose-derived (AD-NSs) and bone marrow-derived NSs (BM-NSs) after being grafted into the injured spinal cord. In three cell-treated groups, very few (<1%) grafted cells survived and these survived cells mainly differentiated into oligodendrocytes at week 12 after injury. Additionally, all the cell-treated groups, especially in the SVZ-treated group showed an increase in host oligodendrocytes than control group. Moreover, the level of selective neurotrophins (NTs) in the SVZ-NSs group were significantly higher than those in the BM-NSs and AD-NSs groups, and the level of NTs in the saline group was also significantly higher than sham group. Therefore, not cell replacement or infusion but neuroprotective action associated with endogenous oligodendrocytes and NTs that active by the grafted NSs may contribute to the functional recovery.

Neural regrowth induced by PLGA nerve conduits and neurotrophin-3 in rats with complete spinal cord transection.

Biomaterials and neurotrophic factors represent two promising strategies for spinal cord injury repair. In this study, a combinatorial approach combining the PLGA nerve conduits and the recombinant human neurotrophin-3 (rhNT3) was utilized in a spinal cord injury animal model. After complete transection of the thoracic cord in rats, rhNT3 was administered as a single dose to the host cord caudal to a 2-mm conduit. Axonal regrowth was enhanced, as indicated by immunostaining and neurofilament-positive area measurement. Neural regrowth was further demonstrated via the retrograde tracing across the lesion. The animals implanted with the PLGA scaffold and rhNT3 exhibited significantly improved performance in BBB rating scale and grid walk tests. These observations suggest that PLGA nerve conduits combined with exogenous NT3 may serve as an alternative therapeutic approach for spinal cord injury repair.

Comparison of Transdifferentiated and Untransdifferentiated Human Umbilical Mesenchymal Stem Cells in Rats after Traumatic Brain Injury

Transdifferentiated and untransdifferentiated mesenchymal stem cells (MSCs) have shown therapeutic benefits in central nervous system (CNS) injury. However, it is unclear which would be more appropriate for transplantation. To address this question, we transplanted untransdifferentiated human umbilical mesenchymal stem cells (HUMSCs) and transdifferentiated HUMSCs (HUMSC-derived neurospheres, HUMSC-NSs) into a rat model of traumatic brain injury. Cognitive function, cell survival and differentiation, brain tissue morphology and neurotrophin expression were compared between groups. Significant improvements in cognitive function and brain tissue morphology were seen in the HUMSCs group compared with HUMSC-NSs group, which was accompanied by increased neurotrophin expression. Moreover, only few grafted cells survived in both the HUMSCs and HUMSC-NSs groups, with very few of the cells differentiating into neural-like cells. These findings indicate that HUMSCs are more appropriate for transplantation and their therapeutic benefits may be associated with neuroprotection rather than cell replacement.

Comparison of the Neural Differentiation Potential of Human Mesenchymal Stem Cells from Amniotic Fluid and Adult Bone Marrow

Human mesenchymal stem cells (MSCs) are considered a promising tool for cell-based therapies of nervous system diseases. Bone marrow (BM) has been the traditional source of MSCs (BM-MSCs). However, there are some limitations for their clinical use, such as the decline in cell number and differentiation potential with age. Recently, amniotic fluid (AF)-derived MSCs (AF-MSCs) have been shown to express embryonic and adult stem cell markers, and can differentiate into cells of all three germ layers. In this study, we isolated AF-MSCs from second-trimester AF by limiting dilution and compared their proliferative capacity, multipotency, neural differentiation ability, and secretion of neurotrophins to those of BM-MSCs. AF-MSCs showed a higher proliferative capacity and more rapidly formed and expanded neurospheres compared to those of BM-MSCs. Both immunocytochemical and quantitative real-time PCR analyses demonstrated that AF-MSCs showed higher expression of neural stemness markers than those of BM-MSCs following neural stem cell (NSC) differentiation. Furthermore, the levels of brain-derived growth factor and nerve growth factor secreted by AF-MSCs in the culture medium were higher than those of BM-MSCs. In addition, AF-MSCs maintained a normal karyotype in long-term cultures after NSC differentiation and were not tumorigenic in vivo. Our findings suggest that AF-MSCs are a promising and safe alternative to BM-MSCs for therapy of nervous system diseases.