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Acute and subchronic dermal toxicity of nanosilver in guinea pig
Korani M, Rezayat SM, Gilani K, Arbabi Bidgoli S, Adeli S
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S17065
Abstract: cute and subchronic dermal toxicity of nanosilver in guinea pig Original Research (6705) Total Article Views Authors: Korani M, Rezayat SM, Gilani K, Arbabi Bidgoli S, Adeli S Published Date April 2011 Volume 2011:6 Pages 855 - 862 DOI: http://dx.doi.org/10.2147/IJN.S17065 M Korani1, SM Rezayat1,2,4, K Gilani3, S Arbabi Bidgoli4, S Adeli1 1Department of Pharmacology, Faculty of Medicine, Tehran University of Medical Sciences; 2Department of Nanotechnology, Faculty of Advanced Sciences and Technology in Medicine, Tehran University of Medical Sciences; 3Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences; 4Department of Toxicology & Pharmacology, Faculty of Pharmacy, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran Abstract: Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner.
PREPARATION OF COLLAGEN-SULFONATED CARBOXYMETHYL CHITOSAN/SILICONE MEMBRANE BILAYER DERMAL EQUIVALENT AND ITS APPLICATION IN THE TREATMENT OF SCALDS OF PORCINE SKIN
胶原-磺化羧甲基壳聚糖/硅橡胶皮肤再生材料的制备及其对小型猪烫伤创面全层皮肤缺损的修复研究

HUANG Aibin,GUO Rui,XU Shaojun,MA Lie,GAO Changyou,
黄爱宾
,郭瑞,徐少骏,马列,高长有

高分子学报 , 2009,
Abstract: A dermal equivalent applied in the treatment of scalds has been attracting much attention.We report here the fabrication of a bilayer dermal equivalent(BDE) composed of collagen-sulfonated carboxymethyl chitosan(SCC) porous scaffold and silicone membrane,and its application for accelerating the healing of skin scalds in a Bama miniature pig model.Firstly,the SCC was synthesized,and its chemical structure was characterized by FTIR and ~1H-NMR.Then the effect of the ratio of the SCC on the microstructure of t...
Constru o de substituto da pele composto por matriz de colágeno porcino povoada por fibroblastos dérmicos e queratinócitos humanos: avalia o histológica Construction of a skin substitute composed of porcine collagen matrix populated with human dermal fibroblasts and keratinocytes: histological evaluation  [cached]
Cesar Isaac,Francinni M. P. Rego,Pedro Ribeiro Soares de Ladeir,Silvana C. Altram
Revista Brasileira de Cirurgia Plástica , 2012,
Abstract: INTRODU O: O uso de enxertos autólogos é limitado pela extens o da área doadora e pelo estado clínico dos pacientes, no caso de les es extensas. Alotransplantes coletados de cadáveres ou voluntários s o rejeitados após uma ou duas semanas, servindo apenas como cobertura temporária para essas les es. O tratamento de grandes les es cutaneas com tegumento autólogo reconstruído constitui alternativa atraente, já que, a partir de um pequeno fragmento de pele do paciente, pode-se obter culturas de células que se multiplicam rapidamente e podem ser criopreservadas, permitindo, assim, sua utiliza o em novos tratamentos por tempo indeterminado. Este estudo pretendeu avaliar o comportamento histológico de queratinócitos e fibroblastos humanos cultivados sobre uma matriz de colágeno porcino derivada da submucosa intestinal. MéTODO: Células da epiderme e derme humana foram cultivadas separadamente e semeadas sobre matriz de colágeno porcino, onde permaneceram em ambiente controlado por 21 dias, antes de serem submetidas a análise histológica. RESULTADOS: Observou-se que os fibroblastos invadem e colonizam a matriz de colágeno, enquanto os queratinócitos se organizam de forma laminar e estratificada sobre a superfície em que foram semeados. CONCLUS ES: A utiliza o da matriz de colágeno porcino como carreador de células da pele humana é possível e a organiza o dessas células se assemelha à arquitetura da pele humana. BACKGROUND: In the case of extensive lesions, the use of autologous grafts is limited by the extent of the donor area and the clinical condition of patients. Allografts collected from cadavers or volunteers are usually rejected after 1 to 2 weeks, thus serving only as temporary cover for these lesions. Treating major cutaneous lesions with reconstructed autologous skin is an attractive alternative, because it is possible to obtain cultures of cells that multiply rapidly and can be cryopreserved from a small fragment of the patient's skin, thereby facilitating its indefinite use in new treatments. This study evaluated the histological behavior of cultured human keratinocytes and fibroblasts on a collagen matrix derived from porcine small intestinal submucosa. METHODS: Cells from human epidermis and dermis were grown separately and seeded on porcine collagen matrix, which was maintained in a controlled environment for 21 days before being subjected to histological analysis. RESULTS: Fibroblasts invaded and colonized the collagen matrix, whereas keratinocytes were organized in laminated and stratified layers on the surface on which they were seeded. CON
Clinical experience with a novel bovine collagen dura mater substitute
Costa, Bruno Silva;Cavalcanti-Mendes, George de Albuquerque;Abreu, Marcelo Sartori de;Sousa, Atos Alves de;
Arquivos de Neuro-Psiquiatria , 2011, DOI: 10.1590/S0004-282X2011000200015
Abstract: dural substitutes are used to achieve watertight closure of the dura mater when adequate closure is not possible. the purpose of this study was to evaluate the efficacy and safety of a new collagen matrix dural substitute (duradry, technodry, belo horizonte mg) in the repair or expansion of cranial and spinal dura mater. method: thirty patients, operated on between march and september, 2008, were studied. surgical records were reviewed for sex, age, location of graft, technique, and presence of fistula or infection. the patients were followed up for at least 3 months, and presence of complications, such as cerebrospinal fluid leakage, infection, asseptic meningitis hydrocephalus, pseudomeningocele, was analyzed. results: only one patient presented cerebrospinal fluid fistula. no patients presented wound infections, hydrocephalus, pseudomenigocele, meningites, brain abscesses or signs of toxicity related to the dural substitute. conclusion: the new dural substitute used in this study is effective and safe, and the initial results are similar to those of other dural substitutes reported in the literature.
Acute and subchronic dermal toxicity of nanosilver in guinea pig  [cached]
Korani M,Rezayat SM, Gilani K,Arbabi Bidgoli S,Adeli S
International Journal of Nanomedicine , 2011,
Abstract: M Korani1, SM Rezayat1,2,4, K Gilani3, S Arbabi Bidgoli4, S Adeli11Department of Pharmacology, Faculty of Medicine, Tehran University of Medical Sciences; 2Department of Nanotechnology, Faculty of Advanced Sciences and Technology in Medicine, Tehran University of Medical Sciences; 3Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences; 4Department of Toxicology & Pharmacology, Faculty of Pharmacy, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, IranAbstract: Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner.Keywords: nanosilver, acute dermal toxicity, subchronic dermal toxicity
Evaluation of Dermal Substitute in a Novel Co-Transplantation Model with Autologous Epidermal Sheet  [PDF]
Guofeng Huang,Shizhao Ji,Pengfei Luo,Yunqing Zhang,Guangyi Wang,Shihui Zhu,Shichu Xiao,Zhaofan Xia
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049448
Abstract: The development of more and more new dermal substitutes requires a reliable and effective animal model to evaluate their safety and efficacy. In this study we constructed a novel animal model using co-transplantation of autologous epidermal sheets with dermal substitutes to repair full-thickness skin defects. Autologous epidermal sheets were obtained by digesting the basement membrane (BM) and dermal components from rat split-thickness skins in Dispase II solution (1.2 u/ml) at 4°C for 8, 10 and 12 h. H&E, immunohistochemical and live/dead staining showed that the epidermal sheet preserved an intact epidermis without any BM or dermal components, and a high percentage of viable cells (92.10±4.19%) and P63 positive cells (67.43±4.21%) under an optimized condition. Porcine acellular dermal matrixes were co-transplanted with the autologous epidermal sheets to repair full-thickness skin defects in Sprague-Dawley rats. The epidermal sheets survived and completely re-covered the wounds within 3 weeks. Histological staining showed that the newly formed stratified epidermis attached directly onto the dermal matrix. Inflammatory cell infiltration and vascularization of the dermal matrix were not significantly different from those in the subcutaneous implantation model. Collagen IV and laminin distributed continuously at the epidermis and dermal matrix junction 4 weeks after transplantation. Transmission electron microscopy further confirmed the presence of continuous lamina densa and hemidesmosome structures. This novel animal model can be used not only to observe the biocompatibility of dermal substitutes, but also to evaluate their effects on new epidermis and BM formation. Therefore, it is a simple and reliable model for evaluating the safety and efficacy of dermal substitutes.
Collagen-Binding Peptidoglycans Inhibit MMP Mediated Collagen Degradation and Reduce Dermal Scarring  [PDF]
Kate Stuart, John Paderi, Paul W. Snyder, Lynetta Freeman, Alyssa Panitch
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022139
Abstract: Scarring of the skin is a large unmet clinical problem that is of high patient concern and impact. Wound healing is complex and involves numerous pathways that are highly orchestrated, leaving the skin sealed, but with abnormal organization and composition of tissue components, namely collagen and proteoglycans, that are then remodeled over time. To improve healing and reduce or eliminate scarring, more rapid restoration of healthy tissue composition and organization offers a unique approach for development of new therapeutics. A synthetic collagen-binding peptidoglycan has been developed that inhibits matrix metalloproteinase-1 and 13 (MMP-1 and MMP-13) mediated collagen degradation. We investigated the synthetic peptidoglycan in a rat incisional model in which a single dose was delivered in a hyaluronic acid (HA) vehicle at the time of surgery prior to wound closure. The peptidoglycan treatment resulted in a significant reduction in scar tissue at 21 days as measured by histology and visual analysis. Improved collagen architecture of the treated wounds was demonstrated by increased tensile strength and transmission electron microscopy (TEM) analysis of collagen fibril diameters compared to untreated and HA controls. The peptidoglycan's mechanism of action includes masking existing collagen and inhibiting MMP-mediated collagen degradation while modulating collagen organization. The peptidoglycan can be synthesized at low cost with unique design control, and together with demonstrated preclinical efficacy in reducing scarring, warrants further investigation for dermal wound healing.
Synthetic Bone Substitute Engineered with Amniotic Epithelial Cells Enhances Bone Regeneration after Maxillary Sinus Augmentation  [PDF]
Barbara Barboni, Carlo Mangano, Luca Valbonetti, Giuseppe Marruchella, Paolo Berardinelli, Alessandra Martelli, Aurelio Muttini, Annunziata Mauro, Rossella Bedini, Maura Turriani, Raffaella Pecci, Delia Nardinocchi, Vincenzo Luca Zizzari, Stefano Tetè, Adriano Piattelli, Mauro Mattioli
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063256
Abstract: Background Evidence has been provided that a cell-based therapy combined with the use of bioactive materials may significantly improve bone regeneration prior to dental implant, although the identification of an ideal source of progenitor/stem cells remains to be determined. Aim In the present research, the bone regenerative property of an emerging source of progenitor cells, the amniotic epithelial cells (AEC), loaded on a calcium-phosphate synthetic bone substitute, made by direct rapid prototyping (rPT) technique, was evaluated in an animal study. Material And Methods Two blocks of synthetic bone substitute (~0.14 cm3), alone or engineered with 1×106 ovine AEC (oAEC), were grafted bilaterally into maxillary sinuses of six adult sheep, an animal model chosen for its high translational value in dentistry. The sheep were then randomly divided into two groups and sacrificed at 45 and 90 days post implantation (p.i.). Tissue regeneration was evaluated in the sinus explants by micro-computer tomography (micro-CT), morphological, morphometric and biochemical analyses. Results And Conclusions The obtained data suggest that scaffold integration and bone deposition are positively influenced by allotransplantated oAEC. Sinus explants derived from sheep grafted with oAEC engineered scaffolds displayed a reduced fibrotic reaction, a limited inflammatory response and an accelerated process of angiogenesis. In addition, the presence of oAEC significantly stimulated osteogenesis either by enhancing bone deposition or making more extent the foci of bone nucleation. Besides the modulatory role played by oAEC in the crucial events successfully guiding tissue regeneration (angiogenesis, vascular endothelial growth factor expression and inflammation), data provided herein show that oAEC were also able to directly participate in the process of bone deposition, as suggested by the presence of oAEC entrapped within the newly deposited osteoid matrix and by their ability to switch-on the expression of a specific bone-related protein (osteocalcin, OCN) when transplanted into host tissues.
11β-Hydroxysteroid Dehydrogenase 1 Specific Inhibitor Increased Dermal Collagen Content and Promotes Fibroblast Proliferation  [PDF]
Mika Terao, Mamori Tani, Saori Itoi, Takuji Yoshimura, Toshimitsu Hamasaki, Hiroyuki Murota, Ichiro Katayama
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093051
Abstract: Glucocorticoids (GCs) are one of the most effective anti-inflammatory drugs for treating acute and chronic inflammatory diseases. However, several studies have shown that GCs alter collagen metabolism in the skin and induce skin atrophy. Cortisol is the endogenous GC that is released in response to various stressors. Over the last decade, extraadrenal cortisol production in various tissues has been reported. Skin also synthesizes cortisol through a de novo pathway and through an activating enzyme. 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) is the enzyme that catalyzes the conversion of hormonally inactive cortisone to active cortisol in cells. We previously found that 11β-HSD1 negatively regulates proliferation of keratinocytes. To determine the function of 11β-HSD1 in dermal fibroblasts and collagen metabolism, the effect of a selective 11β-HSD1 inhibitor was studied in mouse tissues and dermal fibroblasts. The expression of 11β-HSD1 increased with age in mouse skin. Subcutaneous injection of a selective 11β-HSD1 inhibitor increased dermal thickness and collagen content in the mouse skin. In vitro, proliferation of dermal fibroblasts derived from 11β-HSD1 null mice (Hsd11b1?/? mice) was significantly increased compared with fibroblasts from wild-type mice. However, in vivo, dermal thickness of Hsd11b1?/? mice was not altered in 3-month-old and 1-year-old mouse skin compared with wild-type mouse skin. These in vivo findings suggest the presence of compensatory mechanisms in Hsd11b1?/? mice. Our findings suggest that 11β-HSD1 inhibition may reverse the decreased collagen content observed in intrinsically and extrinsically aged skin and in skin atrophy that is induced by GC treatment.
In Vitro Analysis of VEGF and HGF Production by Fibroblast in Cultured Dermal Substitute Combined with EGF-Incorporating Top Dressing  [PDF]
Emi Iijima, Daichi Daichi Toyoda, Akiko Yamamoto, Misato Kuroyanagi, Yoshimitsu Yoshimitsu Kuroyanagi
Open Journal of Regenerative Medicine (OJRM) , 2014, DOI: 10.4236/ojrm.2014.31002
Abstract:

This study aimed to investigate the potential of cultured dermal substitute (CDS) to release angiogenic growth factors when laminated with a membrane containing epidermal growth factor (EGF) as a top dressing. Membranes were prepared by air-drying a solution of hyaluronic acid (HA) and collagen (Col) with or without EGF. Membranes were designed to contain EGF at concentrations of 0, 0.1, 0.2 or 0.5 μg/cm2. CDS was prepared by incorporating fibroblasts into a collagen gel combined with a cross-linked HA spongy matrix, followed by culturing for 5 days. CDS was designed to contain fibroblasts at a density of 2 × 105 (Group I) or 4 × 105 cells/cm2> (Group II). CDS was elevated at the interface between air and culture medium, on the top of which each membrane was placed. This culture system was employed as a wound surface model. Metabolic activity of the fibroblasts in the CDS cultured for 7 days on a wound surface model was measured by MTT assay. The amounts of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) after 7 days of cultivation were measured by using ELISA. Membranes containing EGF ranging from 0.1 to 0.5 μg/cm2> facilitated production of both VEGF and HGF, as compared with control membranes without EGF. However, a membrane containing EGF at a concentration of 0.5 μg/cm2> failed to facilitate fibroblast cytokine production in Group I. These results demonstrated that the EGF-incorporating membrane was able to stimulate fibroblasts in the CDS to synthesize an increased amount of VEGF and HGF in a dose-dependent manner.



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