Dexamethasone increases angiopoietin-1 and quiescent hematopoietic stem cells: a novel mechanism of dexamethasone-induced hematoprotection

Angiopoietin-1 (Ang-1) is known to have hematoprotective effects by increasing the quiescence of hematopoietic stem cells. However, it remains to be determined if the upregulation of Ang-1 and the subsequent increase in the quiescence of hematopoietic stem cells are also involved in the dexamethasone (Dex)-mediated bone marrow protection. Here Western blotting and flow cytometric analyses demonstrate that Dex increases the levels of Ang-1 in mouse bone marrow and the quiescence of hematopoietic stem cells. Our data for the first time suggest that the increased quiescence of hematopoietic stem cells provides a novel mechanism of Dex-induced hematoprotectionope

Electrospun Nanofibrous Membranes for the Engineering of Cultured Skin Substitutes

In this study, nanofibrous membranes from biodegradable PLGA and collagen were fabricated to mimic natural extracellular matrix (ECM) and investigated on the morphology, conformational stability, cytotoxicity and cell attachment. The effect of PLGA or collagen nanofibrous membranes incorporating human dermal fibroblasts on wound healing was also evaluated using an in vivo full thickness dermal defect model. The circular dichroism measurements showed that electrospun collagen maintained its triple helix structure. In cytotoxicity test using L929 fibroblastic cells, electrospun PLGA or collagen nanofibrous membrane demonstrated no significant toxicity. It was also found that collagen and PLGA nanofibers favored cell attachment and proliferation. In vivo testing showed that the regeneration of dermis and epidermis treated with PLGA or collagen nanofibrous membrane incorporating dermal fibroblasts was accelerated. Therefore, this electrospun PLGA or collagen nanofibrous membrane might have potential efficacy in tissue engineering as skin substitutes.ope

A Case of a Giant Cell Tumor of Tendon Sheath in a Child

A giant cell tumor of tendon sheath is a slow growing benign soft tissue tumor that is known by a variety of names including fibrous histiocytoma of tendon sheath and fibrous xanthoma of the synovium. Clinically, it presents as a 1~3 cm firm, non-mobile, painless, nontender mass, and mostly occurs at interphalangeal joints of fingers. It shows female predominance and can occur at any age, but it is most common between the third and fifth decades and is rare in children. We now report the case of a 10-year-old girl with a giant cell tumor of tendon sheath on the toeope

마이코 페놀산에 의한 췌도세포주 사멸의 기전

목적: Mycophenolic acid (MPA)는 췌장이식을 포함한 다양한 종류의 장기이식에 사용되는 면역억제제로 inosine monophosphate dehydrogenase (IMPDH)의 선택적이고 비경쟁적인 억제제이나 췌도세포주에서는 세포 사멸을 유도한다고 알려져 있다. 본 연구에서는 인슐린을 분비하는 췌도 세포주인 HIT-T15 세포를 사용하여, MPA가 세포 사멸을 일으키는 기전을 규명하고자 하였다. 방법: 세포주는 American Type Culture Collection에서 구입하였으며 10% fetal bovine serum이 포함된 RPMI-1640을 사용하여 배양하였다. 세포 활성은 methylthiazoletetrazolium (MTT) assay, 세포 사멸은 annexin V와 PI 염색법, mitogen-activated protein kinase (MAPK) 활성화와 caspase-3 분절은 Western blot 분석으로 측정하였다. 결과: MPA 1μM과 10μM을 처리하였을 때 MTT, caspase-3 분절 그리고 annexin V 염색이 24시간에 농도 의존적으로 증가하였으며, 이는 외부에서 함께 투여한 guanosine 500μM에 의하여 부분적으로 회복되었으나 adenosine 500μM 투여에서는 변화가 없었다. 또한 MPA는 extracellular-regulated protein kinase (ERK), p38 MAPK 그리고 c-jun N-terminal protein kinase (JNK)의 활성화를 8시간과 24시간에서 증가시켰고 guanosine 투여는 이를 부분적으로 회복시켰다. ERK의 억제제인 PD98059, p38 MAPK 억제제인 SB203580 그리고 JNK 억제제인 SP600125는 MPA와 함께 처리하였을 때 각 시간에 증가된 MAPK 활성을 감소시켰지만 MTT와 caspase-3 분절을 살펴본 결과 PD98059는 영향이 없었으며 SB203580은 세포사멸을 증가시켰고, SP600125만이 MPA가 일으킨 세포 사멸을 일부 환원시켰다. Pan-caspase 억제제인 Z-VAD-FMK 또한 세포 사멸을 환원시켰다. 결론: MPA는 MAPK 활성을 IMPDH 의존적으로 증가시키지만, ERKl와 p38 MAPK와는 상관없이, JNK 활성화를 통한 caspase-3 증가의 경로로 췌도 세포 사멸을 유도함을 알 수 있었다.ope

Changes in Serum Cytokine Profile after AEB071 (Sotrastaurin) or Tacrolimus versus Their Combinations in Rat Heterotopic Cardiac Allografts.

BACKGROUND: AEB071, an orally available PKC inhibitor, prevents organ rejection after transplantation in rodents and man. Furthermore, pro-inflammatory cytokines and inflammatory processes are important mediators of transplanted organ rejection. We therefore examined whether single or combination therapies of AEB071 and/or tacrolimus affect cytokine profiles in a rat cardiac allograft model. METHODS: AEB071 (60 mg/kg twice a day) and tacrolimus (0.6 or 1.2 mg/kg once a day) were orally administered daily after cardiac transplantation. Interferon (IFN)-gamma, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10, and tumor necrosis factor (TNF)-alpha levels in serum were subsequently measured 5 days after cardiac transplantation using a multiplex protein assay system. RESULTS: All cytokine levels were significantly depressed in cardiac transplanted rats treated with AEB071, whereas tacrolimus only reduced IFN-gamma, IL-2, IL-4, IL-6, and IL-10 levels. When administered in combination, AEB071 and low- or high-dose tacrolimus had additive effects on IFN-gamma, IL-4, IL-6, and TNF-alpha. CONCLUSIONS: These results suggest that AEB071 inhibits T cell activation by blocking the production of proinflammatory cytokines, and that tacrolimus combined with AEB071 can effectively regulate inflammatory cytokines in the transplantation setting.ope

Fibroblast Growth Factor-2 Induced by Enriched Environment Enhances Angiogenesis and Motor Function in Chronic Hypoxic-Ischemic Brain Injury

This study aimed to investigate the effects of enriched environment (EE) on promoting angiogenesis and neurobehavioral function in an animal model of chronic hypoxic-ischemic (HI) brain injury. HI brain damage was induced in seven day-old CD-1® mice by unilateral carotid artery ligation and exposure to hypoxia (8% O2 for 90 min). At six weeks of age, the mice were randomly assigned to either EE or standard cages (SC) for two months. Rotarod, forelimb-use asymmetry, and grip strength tests were performed to evaluate neurobehavioral function. In order to identify angiogenic growth factors regulated by EE, an array-based multiplex ELISA assay was used to measure the expression in frontal cortex, striatum, and cerebellum. Among the growth factors, the expression of fibroblast growth factor-2 (FGF-2) was confirmed using western blotting. Platelet endothelial cell adhesion molecule-1 (PECAM-1) and α-smooth muscle actin (α-SMA) were also evaluated using immunohistochemistry. As a result, mice exposed to EE showed significant improvements in rotarod and ladder walking performances compared to SC controls. The level of FGF-2 was significantly higher in the frontal cortex of EE mice at 8 weeks after treatment in multiplex ELISA and western blot. On the other hand, FGF-2 in the striatum significantly increased at 2 weeks after exposure to EE earlier than in the frontal cortex. Expression of activin A was similarly upregulated as FGF-2 expression pattern. Particularly, all animals treated with FGF-2 neutralizing antibody abolished the beneficial effect of EE on motor performance relative to mice not given anti-FGF-2. Immunohistochemistry showed that densities of α-SMA+ and PECAM-1+ cells in frontal cortex, striatum, and hippocampus were significantly increased following EE, suggesting the histological findings exhibit a similar pattern to the upregulation of FGF-2 in the brain. In conclusion, EE enhances endogenous angiogenesis and neurobehavioral functions mediated by upregulation of FGF-2 in chronic hypoxic-ischemic brain injury.ope

The Efficacy and Safety of Succinylated Atelocollagen and Adenosine for the Treatment of Periorbital Wrinkles

The degradation of structural collagen contributes to the characteristic appearance of wrinkles. The anti-wrinkle effects of a variety of substances have been studied, but the potential anti-wrinkle effects of topical applications of collagen for periorbital wrinkles have not been investigated. To evaluate the effects of topical application of succinylated atelocollagen on periorbital wrinkles and to compare the results of treatment with adenosine, a clinical study on Korean participants was carried out. Each participant’s right or left periorbital area was treated with either a solution containing succinylated atelocollagen and adenosine or a solution containing only succinylated atelocollagen for two months. A placebo solution was applied to the opposite periorbital area of each patient’s face for two months. Based on objective and subjective measurements of clinical improvement, the assessment scores for treated sites were statistically significantly higher than scores for placebo sites after two months of treatment. Analysis of silicone casts of periorbital wrinkles demonstrated partial effects of succinylated atelocollagen on periorbital wrinkles. However, we did not observe any effects of adenosine on periorbital wrinkles. Succinylated atelocollagen may be an effective treatment option for periorbital wrinkles, but further studies including a longer treatment period and larger subject group are needed to verify these results.ope

Diabetic Ulcers Treated with Bi-Layered Collagen Membrane

Diabetic foot ulcer is a serious clinical problem with significant medical and economic effects on health systems worldwide. Some patients undergo amputation and others experience disability for an extended period of time. Treatment of diabetic foot ulcer is complex and difficult. Even with proper management, the wounds may not heal as well as expected. To promote wound healing, many advanced topical dressing materials have been developed. Among them, bi-layered collagen membrane, which is composed of collagen and hyaluronic acid, is believed to enhance wound healing. Herein we report two cases of diabetic foot ulcer which were successfully treated using bi-layered collagen membranesope

Cellular Viability of Cryopreserved Porcine Valve According to Warm Ischemic Time

Background: Valve replacement using cryopreserved valved homograft is increasing because of resistance of infection and excellent hemodynamics. The viability of fibroblast which is related with warm ischemic time affects the durability of implanted cryopreserved valved homograft. We evaluated how long the warm schemic time is acceptable by examining the viability of cells depending upon warm ischemic time. Material and Method: 1. Retrieval of tissues; Thirty-two slaughted porcine heart and lung enblocs were stored at refrigerator(4 ∼8 ℃) for various time period(Warm Ischemic Time), and the heart was dissected and stored in Hartman solution at 4 ℃for 24 hours(Cold Ischemic Time) as the simulation of retrieval and dissection of human heart. The hearts were assigned to groups A(2 hours), B(12 hours), C(24 hours), D(36 hours) depending on warm ischemic time. 2. Sterilization; The valved homografts were sterilized in the RPMI 1640 solution with antibiotics. 3. Freezing and Storage; The homografts were freezed by computerized freezer , stored 7 days at liquid nitrogen tank, and thawed. 4. Evaluation of the viability; The viability was evaluated by Triphan blue test after warm ischemic time, after cold ischemic time and after thawing. 5. Analysis; The viability of fibroblast was analysed by pearson correlation test of SAS program. Result: 1. The viability between after cold ischemic time and after thawing was not different(p=0.619) for the adequacy of sterilization, freezing and thawing. 2. The viability which was evaluated after warm ischemic time, cold ischemic time and thawing, and the various warm ischemic times are strongly correlated as R is -0.857, -0.673 and -0.549 respectively. The viability of tricuspid valve is well related with the viability of aortic valve. Conclusion: 1. The longer the warm ischemic time, the lesser the viability of fibroblast. The viability of fibroblast after cryopreservation was decreased less 60% if the warm ischemic time was over 12 hours. 2. The method of cryopreservation is acceptable for maintaining the viability of fibroblast, and the viability of tricuspid valve may be the indicator of the viability of aortic valve. 3. However, the study for the optimal viability which is necessary to the durabiltiy of implanted valved homograft is needed.ope

Retinoic Acid-induced Differentiation of Rat Mesenchymal Stem Cells into β-Cell Lineage

Backgrounds: Type I diabetes mellitus (T1DM), an autoimmune disease, is associated with insulin deficiency due to the death of β-cells. Bone marrow-derived mesenchymal stem cells (BM-MSCs) are capable of tissue repair and thus are a promising source of β-cell surrogates. Methods: In this study, the therapeutic potential of BM-MSCs as β-cell replacements was analyzed both in vitro and in vivo. First, we used retinoic acid (RA) to induce rat BM-MSCs to differentiate into cells of endodermal/pancreatic lineage. Then, differentiated rat BM-MSCs were syngeneically injected under the renal capsule of rats. Results: Analysis of gene expression revealed that rat BM-MSCs showed signs of early pancreatic development, and differentiated cells were qualitatively and quantitatively confirmed to produce insulin in vitro. In vivo study was performed for short-term (3 weeks) and long-term (8 weeks) period of time. Rats that were injected with differentiated MSCs exhibited a reduction in blood glucose levels throughout 8 weeks, and grafted cells survived in vivo for at least 3 weeks. Conclusions: These findings show that RA can induce differentiation of MSCs into the β-cell lineage and demonstrate the potential of BM-MSCs to serve as therapeutic tools for T1DM.ope