Search

Our aim was to provide a new animal model for intractable skin ulcers in irradiated rats. Twenty-four rats were irradiated with total single radiographic irradiation doses of 10, 15, 20, and 30 Gy. The skin was observed for 6 months. In the 10-Gy group, there were no visible changes to the skin. In the 15-Gy group, epilation and depigmentation were seen about 2 weeks after irradiation. In the groups over 20-Gy, minor erosion or skin ulcers appeared in most rats. The wounds healed in the 20-Gy group, but many in the 30-Gy group could not be healed. A further 36 rats were irradiated with 20 Gy, and this was followed by the creation of cutaneous full-thickness defects at different periods. The size of the wounds was measured on days 0, 3, 5, 7, 10, and 14. Delayed wound healing was found in the irradiated groups compared with the unirradiated group ( p == 0.01). There were no differences in the time of ulceration, except in the Day 7 group ( p == 0.03). [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate effects of human platelet-rich plasma (PRP)-containing fragmin/protamine microparticles (F/P MPs) as a protein carrier on neovascularization and granulation tissue formation. Frozen and thawed PRP contains high concentrations of various growth factors (GFs) and F/P MPs effectively adsorb those GFs. Human microvascular endothelial cells (MVECs) and dermal fibroblast cells (DFCs) were optimally grown in medium containing 4% PRP and the addition of F/P MPs significantly maintained and protected the proliferative activity of PRP incubated at 37°C for more than 10 days. When PRP-containing F/P MPs were subcutaneously injected into the back of mice, significant neovascularization was induced near the injected site with enhanced filtration of inflammatory cells from day 3 to day 30, compared with controls (injections of PRP, F/P MPs, and saline). Both PRP-containing F/P MPs and PRP alone induced significant formation of granulation tissue at the injected site. However, thickness of induced granulation tissues was well maintained for 30 days only in PRP-containing F/P MP-injected group. Those bound GFs may be gradually diffused and released from F/P MPs in vitro and in vivo. Thereby, PRP-containing F/P MPs offer significantly higher inductions of vascularization and fibrous tissue formation in vivo than PRP alone. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the potential accelerating effects of an adipose tissue-derived stromal cells (ATSC)-containing atelocollagen matrix with silicone membrane (ACMS) for repairing mitomycin C-treated healing-impaired wounds. Mitomycin C was applied to full-thickness skin incisions in this study to create a healing-impaired wound model in rat. After thoroughly washing out the mitomycin C from the wound, ACMS alone or ATSC-containing ACMS was applied to the wounds. Histological sections of the wounds were then prepared at indicated time periods after the treatments. These results indicated significantly advanced granulation tissue and capillary formations in the healing-impaired wounds treated with ATSC-containing ACMS compared with those treated with ACMS alone. Thus, this study suggested that transplantation of inbred ATSC-containing ACMS is effective for repairing healing-impaired wounds. [ABSTRACT FROM AUTHOR]

Purpose: Although treatments for alopecia are in high demand, not all treatments are safe and reliable. Dalteparin/protamine nanoparticles (D/P NPs) can effectively carry growth factors (GFs) such as fibroblast GF (FGF)-2. The purpose of this study was to identify the effects of FGF-2-containing D/P NPs (FGF-2&D/P NPs) on hair growth., Patients and Methods: In this study, the participants were 12 volunteers with thin hair. One milliliter of FGF-2 (100 ng/mL) and D/P NPs (56 μg/mL) was applied and massaged on the skin of the scalp by the participants twice a day. They were evaluated for 6 months. Participants were photographed using a digital camera for general observation and a hair diagnosis system for measuring hair diameter., Results: The mean diameter of the hairs was significantly higher following the application of FGF-2&D/P NPs for 6 months. Objective improvements in thin hair were observed in two cases. Nine participants experienced greater bounce and hair resilience., Conclusion: The transdermal application of FGF-2&D/P NPs to the scalp can be used as a new treatment for alopecia.

Cardiac interventional radiology (IVR) has gained popularity since the late 1980s. An extensive search of literature published from 1996 to 2009 identified 78 reports regarding radiation-induced skin injuries (RISI) following cardiac IVR. The authors present a case report and a review of the relevant literature. A 59-year-old man underwent percutaneous transluminal coronary angioplasty (PTCA). The estimated cumulative skin dose was 11.8 Gy. The patient discovered erosions on the right upper arm 2 months after PTCA. The lesion did not resolve with conservative treatment, and evolved into an intractable skin ulcer. The authors surgically removed the lesion and reconstructed the defect using an anterolateral thigh (ALT) flap. Radiation-induced skin injuries following PTCA usually develop on the back, and rarely on the upper arm. Radiation ulceration commonly requires surgical intervention. Physicians should be aware of the possibility of RISI, and thus, take measures to minimize exposure of patients and staff to radiation. .

We examined the effects of prostaglandin E₁ (PGE₁) on radiation-induced proliferation inhibition and apoptosis in keratinocytes and healing of radiation-induced skin injury in a rat model. PGE₁ had a protective effect on radiation-induced growth inhibition in keratinocytes in vitro, but not in fibroblasts. Varying concentrations of PGE₁ were subcutaneously administered into the posterior neck region. X-irradiation at a dose of 20 Gy was administrated to the lower part of the back using a lead sheet with two holes 30 min to 1 h before or after the administration of PGE₁. Although X-irradiation induced epilation, minor erosions, or skin ulcers in almost all rats, PGE₁ administration prior to irradiation reduced these irradiation injuries. Staining with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling showed that proportions of apoptotic keratinocytes in the X-irradiated skin of PGE₁-administered rats were significantly lower than for those in the skin of rats which did not receive PGE₁. Cutaneous full-thickness defective wounds were then formed in X-irradiated areas to examine the time course of wound healing. Wound healing was significantly delayed because of X-irradiation, but PGE₁ administration prior to irradiation led to a significantly shorter delay in wound healing compared with controls. Decreasing delay in wound healing was correlated with concentration of PGE₁ administrated. Thus, PGE₁-administration may potentially alleviate the radiation-induced skin injury.

Intractable skin ulcers resulting from diabetes, ischemia and collagen diseases represent significant problems with few solutions. Cell-based therapy may hold promise in overcoming such disorders. In order to establish a suitable experimental model for the treatment of such ulcers using stem cells, this chapter describes detailed methods for: (1) isolation of stem cells from adipose tissue, termed adipose-derived stem cells (ASCs), (2) preparing a hybrid-type artificial dermis that consists of a type I collagen sponge and ASCs, (3) preparing intractable ulcers using Mitomycin C, and (4) evaluating the effect of wound healing histologically. ASCs seeded onto a type I collagen sponge are applied to intractable ulcers induced by topical application of Mitomycin C. Histological evaluation after 1 and 2 weeks revealed an increase in capillary density and granulation thickness of the hybrid-type artificial dermis. These findings suggest that ASCs may have a positive effect on wound healing and may be a useful tool for future cell-based therapy.

We aimed to evaluate the effectiveness of the application of an atelocollagen matrix containing autologous adipose tissue-derived stromal cells (ASCs) on wound healing in diabetic (db/db) mice. Cultured ASCs from db/db mice and from db/+ mice secreted identical amounts of growth factors, cytokines, and type I collagen. ASCs from db/db mice proliferated at the same rate as those from db/+ mice. When DiI-labeled ASCs were applied to full-thickness round skin wounds on the backs of diabetic db/db mice, histological observation at 2 weeks showed that red fluorescent-labeled tissues were formed in the epidermis, dermis, and capillaries. Twelve db/db mice were treated with either matrix alone or matrix containing ASCs and then sacrificed at 1 or 2 weeks. A histological examination demonstrated significantly advanced granulation tissue formation, capillary formation, and epithelialization in those wounds treated with atelocollagen matrix containing ASCs, compared with wounds treated with matrix alone.

Low-molecular-weight heparin/protamine microparticles (LH/P MPs) serve as carriers for controlled release of heparin-binding cytokines. LH/P MPs were stably coated onto plastic surfaces by drying. The purpose of this study is to evaluate a culture method for selective expansion of CD34+ cells using LH/P MPs as cytokine-binding matrix. Ficoll-purified mouse bone marrow cells (mouse FP-BMCs) containing CD34+ cells were cultured on LH/P MP-coated plates in the presence of stem cell factor (SCF), thrombopoietin (Tpo), and Flt-3 ligand (Flt-3) in hematopoietic progenitor growth medium (HPGM) supplemented with 4% heat-inactivated fetal bovine serum (FBS). After 8 days of culture, the total cell count increased 4.6-fold, and flow cytometry analyses revealed that 23.8% of the initial cells and 57.4% of the expanded cells were CD34 positive. Therefore, CD34+ cells were estimated to have increased 11.0-fold. In contrast, cultured CD34+ cells on uncoated tissue culture plates increased 5.8-fold in an identical medium.

We prepared fragmin/protamine microparticles (F/P MPs) as cell carriers to enhance cell viability. Use of material consisting of a low-molecular-weight heparin (fragmin) mixed with protamine resulted in water-insoluble microparticles (about 0.5-1 microm in diameter). In this study, we investigated the capability of F/P MPs to enhance the viabilities of human microvascular endothelial cells (HMVECs), human dermal fibroblasts (fibroblasts), and adipose tissue-derived stromal cells (ATSCs) in suspension culture. F/P MPs were bound to the surfaces of these cells, and the interaction of these cells with F/P MPs induced cells/F/P MPs-aggregate formations in vitro, and maintained viabilities of those cells for at least 3 days. The ATSCs/F/P MPs-aggregates adhered to and grew on suspension culture plates in a fashion similar to those on type I collagen-coated plates. The cultured ATSCs secreted significant amounts of angiogenic heparin-binding growth factors such as FGF-2. When the ATSCs/F/P MPs-aggregates were subcutaneously injected into the back of nude mice, significant neovascularization and fibrous tissue formation were induced near the site of injection from day 3 to week 2. The ATSCs/F/P MPs-aggregates were thus useful and convenient biomaterials for cell-therapy of angiogenesis., ((c) 2009 Wiley Periodicals, Inc.)

Adipose tissue-derived stromal cells (ATSCs) have recently gained widespread attention as a potential alternate source to bone marrow-derived mesenchymal stem cells with a proliferative capacity and a similar ability to undergo multilineage differentiation. In this study, we evaluated the effectiveness of freshly isolated autologous ATSCs-containing atelocollagen matrix with silicon membrane (ACMS) on wound healing of diabetic (db/db) mice. Cultured ATSCs from (db/db) mice secreted significant amounts of growth factors and cytokines, which are suitable for wound repair. Two full thickness round skin defects were made on the backs of healing-impaired db/db mice. Freshly isolated autologous ATSCs-containing ACMS or ACMS alone were applied to the wounds. Twelve mice were treated and then killed at 1 or 2 weeks (n = 6 each). Histologic sections of the wounds were prepared at each time period after treatment. Histologic examination demonstrated significantly advanced granulation tissue formation, capillary formation, and epithelialization in diabetic healing-impaired wounds treated with autologous ATSCs-containing ACMS, compared with mice treated with ACMS alone. These results suggested that transplantation of autologous ATSCs-containing ACMS significantly accelerated wound healing in diabetic healing-impaired db/db mice.

We produced a chitosan/fucoidan micro complex-hydrogel as a carrier for controlled release of heparin binding growth factors such as fibroblast growth factor (FGF)-2. Material consisting of a soluble chitosan (CH-LA) mixed with fucoidan yielded a water-insoluble and injectable hydrogel with filamentous particles. In this study, we examined the ability of the chitosan/fucoidan complex-hydrogel to immobilize FGF-2 and to protect its activity, as well as the controlled release of FGF-2 molecules. The chitosan/fucoidan complex-hydrogel has high affinity for FGF-2 (K(d) = 5.4 x 10(-) (9)M). The interaction of FGF-2 with chitosan/fucoidan complex-hydrogel substantially prolonged the biological half-life time of FGF-2. It also protected FGF-2 from inactivation, for example by heat and proteolysis, and enhance FGF-2 activity. When FGF-2-containing complex-hydrogel was subcutaneously injected into the back of mice, significant neovascularization and fibrous tissue formation were induced near the site of injection at 1 week, and the complex-hydrogel was biodegraded and disappeared by 4 weeks. These findings indicate that controlled release of biologically active FGF-2 molecules is caused by both slow diffusion and biodegradation of the complex-hydrogel, and that subsequent induction of vascularization occurs. FGF-2-containing chitosan/fucoidan micro complex-hydrogel is thus useful and convenient for treatment of ischemic disease., (Copyright 2007 Wiley Periodicals, Inc.)

A photocrosslinkable chitosan (Az-CH-LA) aqueous solution resulted in an insoluble hydrogel like a soft rubber within 30 sec of ultraviolet light (UV)-irradiation. The photocrosslinked chitosan hydrogel showed strong sealing strength and potential use as a new tissue adhesive in surgical application. Paclitaxel, which is an anti-tumor reagent and a vascularization-inhibitor, retained in the photocrosslinked chitosan hydrogel, and were gradually released from the photocrosslinked chitosan hydrogel in vivo upon the degradation of the hydrogel. The paclitaxel-incorporated photocrosslinked chitosan hydrogels effectively inhibited tumor growth and angiogenesis in mice. On the other hand, the fibroblast growth factor (FGF)-2 molecules also retained in both the photocrosslinked chitosan and an injectable chitosan/IO(4)-heparin hydrogels, and were gradually released from the hydrogels upon their in vivo biodegradations. The activity of FGF-2 in the hydrogels was stable for long time (more than 14 days). The controlled release of biologically active FGF-2 molecules from the hydrogels caused an induction of the angiogenesis and, possibly, collateral circulation occurred in the healing-impaired diabetic (db/db) mice and the ischemic limbs of rats. The purpose of this review is to describe the effectiveness of the chitosan hydrogels (photocrosslinkable chitosan hydrogel and chitosan/IO(4)-heparin hydrogel) as a local drug delivery carrier for FGF-2 and paclitaxel to control wound repair, tumor growth, and angiogenesis. It is thus proposed that the chitosan hydrogels may be a promising new local carrier for drugs such as FGF-2 and paclitaxel.

We have previously described the healing process of full-thickness skin wounds as documented by alkali water cell-maceration scanning electron microscopy. In this study, we examined partial-thickness skin wounds. The present study provided a 3-dimensional visualization of the microarchitecture of the dermal neoformation process in partial-thickness wounds and proved that the development of the papillary dermis proceeded from the stump of the fibrous root sheath and is coupled with the epidermis advancing from the transected hair follicle. The present findings confirm our previously described unit theory as the epithelialization proceeds by forming an "epithelization unit."