Moon-Seo Park

Survival of hypoxic human mesenchymal stem cells is enhanced by a positive feedback loop involving miR-210 and hypoxia-inducible factor 1

The use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for myocardial infarction. However, the poor viability of MSCs after transplantation critically limits the efficacy of this new strategy. The expression of microRNA-210 (miR-210) is induced by hypoxia and is important for cell survival under hypoxic conditions. Hypoxia increases the levels of hypoxia inducible factor-1 (HIF-1) protein and miR-210 in human MSCs (hMSCs). miR-210 positively regulates HIF-1α activity. Furthermore, miR-210 expression is also induced by hypoxia through the regulation of HIF-1α. To investigate the effect of miR-210 on hMSC survival under hypoxic conditions, survival rates along with signaling related to cell survival were evaluated in hMSCs over-expressing miR-210 or ones that lacked HIF-1α expression. Elevated miR-210 expression increased survival rates along with Akt and ERK activity in hMSCs with hypoxia. These data demonstrated that a positive feedback loop involving miR-210 and HIF-1α was important for MSC survival under hypoxic conditions.

Effect of combination therapy with sodium ozagrel and panax ginseng on transient cerebral ischemia model in rats.

Sodium ozagrel (SO) prevents platelet aggregation and vasoconstriction in the cerebral ischemia. It plays an important role in the prevention of brain damage induced by cerebral ischemia/reperfusion. Recently, many animal studies have suggested that the Panax ginseng (PG) has neuroprotective effects in the ischemic brain. In this study, we assessed the neuroprotective effects that come from a combination therapy of SO and PG in rat models with middle cerebral artery occlusion (MCAO). Animals with MCAO were assigned randomly to one of the following four groups: (1) control (Con) group, (2) SO group (3 mg/kg, intravenously), (3) PG group (200 mg/kg, oral feeding), and (4) SO + PG group. The rats were subjected to a neurobehavior test including adhesive removal test and rotarod test at 1, 3, 7, 10, and 15 days after MCAO. The cerebral ischemic volume was quantified by Metamorph imaging software after 2-3-5-triphenyltetrazolium (TTC) staining. The neuronal cell survival and astrocytes expansion were assessed by immunohistofluorescence staining. In the adhesive removal test, the rats of PG or SO + PG group showed significantly better performance than those of the control group (Con: 88.1 ± 24.8, PG: 43.6 ± 11, SO + PG: 11.8 ± 7, P < .05). Notably, the combination therapy group (SO + PG) showed better performance than the SO group alone (SO: 56 ± 12, SO + PG: 11.8 ± 7, P < .05). In TTC staining for infarct volume, cerebral ischemic areas were also significantly reduced in the PG group and SO + PG group (Con: 219 ± 32, PG: 117 ± 8, SO + PG: 99 ± 11, P < .05). Immunohistofluorescence staining results showed that the group which received SO + PG group therapy had neuron cells in the normal range. They also had a low number of astrocytes and apoptotic cells compared with the control or SO group in the peri-infarction area. During astrocytes staining, compared to the SO + PG group, the PG group showed only minor differences in the number of NeuN-positive cells and quantitative analysis of infarct volume. In conclusion, these studies showed that in MCAO rat models, the combination therapy with SO and PG may provide better neuroprotective effects such as higher neuronal cell survival and inhibition of astrocytes expansion than monotherapy with SO alone.

A Pilot Study for the Neuroprotective Effect of Gongjin-dan on Transient Middle Cerebral Artery Occlusion-Induced Ischemic Rat Brain

In this study, we investigated whether gongjin-dan improves functional recovery and has neuroprotective effects on reducing the infarct volume after transient middle cerebral artery occlusion (MCAo). Infarct volume was measured using TTC staining and glucose utilization by F-18 FDG PET. Functional improvement was evaluated with the Rota-rod, treadmill, Garcia score test, and adhesive removal test. At 14 days after MCAo, neuronal cell survival, astrocytes expansion, and apoptosis were assessed by immunohistofluorescence staining in the peri-infarct region. Also, the expression of neurotrophic factors and inflammatory cytokines such as VEGF, BDNF, Cox-2, TNF-α, IL-1β, and IL-1α was measured in ischemic hemisphere regions. The gongjin-dan-treated group showed both reduced infarct volume and increased glucose utilization. Behavior tests demonstrated a significant improvement compared to the control. Also in the gongjin-dan treated group, NeuN-positive cells were increased and number of astrocytes, microglia, and apoptotic cells was significantly decreased compared with the control group in the ischemic peri-infarct area. Furthermore, the expression of VEGF and BDNF was increased and level of Cox-2, TNF-α, IL-1β, and IL-1α was decreased. These results suggest that gongjin-dan may improve functional outcome through the rapid restoration of metabolism and can be considered as a potential neuroprotective agent.

Phorbol myristate acetate differentiates human adipose-derived mesenchymal stem cells into functional cardiogenic cells.

To achieve effective regeneration of injured myocardium, it is important to find physiological way of improving the cardiogenic differentiation of stem cells. Previous studies demonstrated that cardiomyocytes from bone marrow-derived mesenchymal stem cells (BMSCs) activated with phorbolmyristate acetate (PMA), a protein kinase C (PKC) activator, restore electromechanical function in infarcted rat hearts. In this study, we investigated the effect of PMA on cardiogenic differentiation of adipose-derived MSCs (ASCs) for clinical applications. To confirm the effect of PMA, ASCs treated with 1μM PMA were grown for nine days. The expression of cardiac-specific markers (cardiac troponin T, myosin light chain, myosin heavy chain) in PMA-treated MSCs was demonstrated by immunocytochemistry. Alhough few α(1A) receptors exist in ASCs, α(1)-adrenergic receptor subtypes were preferentially expressed in PMA-treated ASCs. Moreover, expression of the β-adrenergic and muscarinic receptors increased in PMA-treated ASCs compared to normal cells. The mRNA levels of Ca(2+)-related factors (SERCA 2a; sarcoplasmic reticulum Ca(2+)-ATPase, LTCC; L-type Ca(2+) channel) in treated ASCs were similar to the levels in cardiomyocytes. Following the transplantation of chemically activated cardiogenic ASCs into infarcted myocardium, histological analysis showed that infarct size, interstitial fibrosis, and apoptotic index were markedly decreased and cardiac function was restored. In conclusion, PMA might induce the cardiogenic differentiation of human ASCs as well as BMSCs. This result suggests successful use of human ASCs in cardiac regeneration therapy.

Therapeutic Effects of Acupuncture through Enhancement of Functional Angiogenesis and Granulogenesis in Rat Wound Healing

Acupuncture regulates inflammation process and growth factors by increasing blood circulation in affected areas. In this study, we examined whether acupuncture has an effect on wound healing in injured rat. Rats were assigned randomly into two groups: control group and acupuncture group. Acupuncture treatment was carried out at 8 sites around the wounded area. We analyzed the wound area, inflammatory cytokines, proliferation of resident cells, and angiogenesis and induction of extracelluar matrix remodeling. At 7 days after-wounding the wound size in acupuncture-treat group was decreased more significantly compared to control group. In addition, the protein levels of proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were significantly decreased compared to the control at 2 and 7 days post-wounding. Also, we analyzed newly generated cells by performing immunostaining for PCNA and using several phenotype markers such as CD-31, α-SMA, and collagen type I. In acupuncture-treated group, PCNA-positive cell was increased and PCNA labeled CD-31-positive vessels, α-SMA- and collagen type I-positive fibroblastic cells, were increased compared to the control group at 7 days post-wounding. These results suggest that acupuncture may improve wound healing through decreasing pro-inflammatory response, increasing cell proliferation and angiogenesis, and inducing extracellular matrix remodeling.

Motor-Evoked Potential Confirmation of Functional Improvement by Transplanted Bone Marrow Mesenchymal Stem Cell in the Ischemic Rat Brain

This study investigated the effect of bone marrow mesenchymal stem cells (BMSCs) on the motor pathway in the transient ischemic rat brain that were transplanted through the carotid artery, measuring motor-evoked potential (MEP) in the four limbs muscle and the atlantooccipital membrane, which was elicited after monopolar and bipolar transcortical stimulation. After monopolar stimulation, the latency of MEP was significantly prolonged, and the amplitude was less reduced in the BMSC group in comparison with the control group (P < .05). MEPs induced by bipolar stimulation in the left forelimb could be measured in 40% of the BMSC group and the I wave that was not detected in the control group was also detected in 40% of the BMSC group. Our preliminary results imply that BMSCs transplanted to the ischemic rat brain mediate effects on the functional recovery of the cerebral motor cortex and the motor pathway.

FOCUSED LOW-INTENSITY PULSED ULTRASOUND ENHANCES BONE REGENERATION IN RAT CALVARIAL BONE DEFECT THROUGH ENHANCEMENT OF CELL PROLIFERATION

A number of studies have reported the therapeutic potential of low-intensity pulsed ultrasound (LIPUS) for induction of bone repair. This study investigated whether bone regeneration might be enhanced by application of focused LIPUS to selectively stimulate fractured calvarial bone. To accomplish this, bone defects were surgically created in the middle of the skull of rats that were subsequently exposed to focused LIPUS. Bone regeneration was assessed by repeated computed tomography imaging after the operation, as well as histologic analysis with calcein, hematoxylin and eosin and proliferating cell nuclear antigen assay. At 6 wk after surgery, bone formation in the focused LIPUS-treated group improved significantly relative to the control. Interestingly, new bone tissue sprouted from focused LIPUS target points. Histologic analysis after exposure to focused LIPUS revealed that proliferating cells were significantly increased relative to the control. Taken together, these results suggest that focused LIPUS can improve re-ossification through enhancement of cell proliferation in calvarial defect sites.

Environmentally relevant levels of Bisphenol A may accelerate the development of type II diabetes mellitus in adolescent Otsuka Long Evans Tokushima Fatty rats

Environmental chemicals may contribute to the development of obesity and metabolic disorders such as diabetes. Bisphenol A (BPA) is one of the environmental chemicals that are widely used in daily life. This study was performed to investigate whether low dose BPA exposure can influence the occurrence of type II diabetes mellitus. Four weeks old Otsuka Long Evans Tokushima Fatty (OLETF) rats were randomly assigned to three groups of five animals and each group was given different concentrations of corn oil with BPA (0, 0.001, and 0.1 mg/kg/day). BPA 0.1 mg/kg/ day produced impairment of glucose tolerance, and induced higher insulin (p=0.028) and malondialdehyde levels (p=0.009) in serum than control group. Serum insulin levels in BPA 0.001 mg/kg/day treated group showed significantly higher than the control group (p=0.016). BPA tended to induce down-regulation of PPARγ mRNA and protein expression in white adipose tissue than control. In conclusion, low dose BPA exposed OLETF rats in adolescent period could accelerate the development of diabetes mellitus in younger adult period.

Therapeutic potential of autologous mesenchymal stem cells derived from synovial fluid in patients with degenerative arthritis

The possibility to isolate synovial fluid-derived mesenchymal stem cells (SFMSCs) from patients with degenerative arthropathy has been an interest since synovial fluid (SF) from osteoarthritis (OA) patients offered a unique stem-cell resource for therapeutic applications. In this study, we successfully isolated, cytogenetically and molecularly characterized, and followed the differentiation potency of human mesenchymal stem cells (MSCs) from SF. The morphology of proliferating SFMSCs showed fibroblast-like morphology, and both the population doubling time (DT) and viability of MSCs from bone marrow, adipose, and SF did not differ. The immunophenotype of SFMSCs was confirmed by the positive expression of CD44, CD73, CD90, CD105, and CD106 by flow cytometry and immunocytochemistry, and the expression of the hematopoietic markers, CD34 and CD45, was not found. In all MSCs from three different origins, we measured the mRNA expression of developmentally important transcript factors such as KLF4, c-Myc, Sox2, and OCT4. SFMSCs from OA patients showed normal chromosomal number, structure, and telomerase activity. SFMSCs showed multipotent capacity, and was differentiated into neurocyte, adipocyte, osteocyte, and chondrocyte in vitro, as demonstrated by specific stains and expression of molecular markers. In addition, SFMSCs also have the capacity to secrete immunomodulating factors (IL-4, IL-10, IL-13, and transforming growth factor-β (TGF-β)) involved in the therapy of rheumatoid arthritis (RA). These results demonstrate that SFMSCs from OA-patients might provide therapeutic options for RA and OA.

The effect of fibroblast growth factor on distinct differentiation potential of cord blood–derived unrestricted somatic stem cells and Wharton's jelly–derived mesenchymal stem/stromal cells

BACKGROUND AIMS Perinatal tissues are considered an attractive source of mesenchymal stem/stromal cells (MSCs) and have unique characteristics depending on their origin. In this study, we compared the basic characteristics of unrestricted somatic stem cells isolated from cord blood (CB-USSCs) and MSCs isolated from Whartons jelly of umbilical cords (WJ-MSCs). We also evaluated the effect of basic fibroblast growth factor (bFGF) supplementation on the growth and differentiation of these cells. METHODS CB-USSCs and WJ-MSCs were isolated from the same individual (n = 6), and their morphology, cell surface antigens, proliferation, expression of stemness markers and adipogenic, osteogenic and chondrogenic differentiation potentials were evaluated. Their morphology, proliferation and differentiation potentials were then also compared in the presence of bFGF supplementation (10 ng/mL). RESULTS Overall, CB-USSCs expressed DLK-1 and negative for all the HOX gene markers. The expression of cell surface antigen CD90, growth capacity and adipogenic differential potential of CB-USSCs were lower than those of WJ-MSCs. WJ-MSCs showed higher growth capacity, but the expression of CD73 and CD105 and their osteogenic differentiation potential were lower than those of CB-USSCs. The spindle morphology of both CB-USSCs and WJ-MSCs and the growth and adipogenic differentiation of CB-USSCs were improved by bFGF supplementation. However, the bFGF supplement did not have any positive effect on the tri-lineage differentiation potentials of WJ-MSCs. CONCLUSIONS CB-USSCs and WJ-MSCs each had distinct characteristics including different growth capacity, distinguishable cell surface markers and distinct adipogenic and osteogenic potentials. bFGF supplementation improved the growth capacity and adipogenic differentiation of CB-USSCs.