Adipose tissue in bone regeneration - stem cell source and beyond

Adipose tissue (AT) is recognized as a complex organ involved in major home-ostatic body functions, such as food intake, energy balance, immunomodulation, development and growth, and functioning of the reproductive organs. The role of AT in tissue and organ homeostasis, repair and regeneration is increasingly recognized. Different AT compartments (white AT, brown AT and bone marrow AT) and their interrelation with bone metabolism will be presented. AT-derived stem cell populations - adipose-derived mesenchymal stem cells and pluripotent-like stem cells. Multilineage differentiating stress-enduring and dedifferentiated fat cells can be obtained in relatively high quantities compared to other sources. Their role in different strategies of bone and fracture healing tissue engineering and cell therapy will be described. The current use of AT- or AT-derived stem cell populations for fracture healing and bone regenerative strategies will be presented, as well as major challenges in furthering bone regenerative strategies to clinical settings.     

IGF-1联合BMP-2对糖尿病合并骨质疏松股骨骨折大鼠中的骨折愈合影响分析

摘要 目的：探讨胰岛素生长因子-1（insulin-like growth factor, IGF-1）联合骨形态发生蛋白（bone morphogenetic protein,BMP）-2对糖尿病合并骨质疏松股骨骨折大鼠中的骨折愈合影响。方法：8周龄雌性SD大鼠60只,饲养一周后根据随机数字表法进行分组,每组12只,之后进行造模,造模成功50只,成功率为83.33 %。将其分为5组,包括正常组（n=10）,糖尿病+卵巢切除+骨折组（n=9）,糖尿病+卵巢切除+骨折+ IGF-1组（骨折处注射IGF 30 μg/kg,n=11）,糖尿病+卵巢切除+骨折+BMP-2组（骨折处注射100 μL BMP-2基因慢病毒1×10⁸,n=10）、糖尿病+卵巢切除+骨折+IGF-1+BMP-2组（参照上述,n=10）,其余进行等剂量溶剂注射,均连续注射两天。分组处理6周后,观察5组大鼠的一般情况。对比5组大鼠的血清钙、骨钙素、碱性磷酸酶水平,对比5组的最大应力、最大载荷及刚度,检测5组大鼠组织中的IGF-1、BMP-2及TGF-β1 mRNA表达水平。结果：A组大鼠无明显异常反应,大鼠体重逐渐增加,大小便、饮食均正常,毛色光亮;B、C、D、E组大鼠精神萎靡、反应迟缓、毛色光亮性较差、体重无明显减轻或增加、大鼠的饮水量、饮食增加,多尿症状较为明显。5组大鼠的血清钙、骨钙素、碱性磷酸酶水平：B组结论：IGF-1联合BMP-2可促进糖尿病合并骨质疏松股骨骨折大鼠中的骨折愈合。     

加味苦参汤联合紫归解毒膏对肛瘘术后创面愈合、肛肠动力学及血清TNF-α、IL-6、bFGF、TGF-β1水平的影响

目的:探讨加味苦参汤联合紫归解毒膏对肛瘘术后创面愈合、肛肠动力学及血清肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、转移生长因子-β1(TGF-β1)、碱性成纤维细胞生长因子(bFGF)水平的影响。方法:选取2015年6月~2019年6月期间我院收治的肛瘘术后患者80例,以随机数字表法将患者分为研究组(n=40,加味苦参汤联合紫归解毒膏治疗)和对照组(n=40,紫归解毒膏治疗),均治疗14 d。比较两组患者疗效、创面愈合情况、肛肠动力学及相关血清细胞因子水平,记录两组患者不良反应发生情况。结果:研究组治疗14 d后的临床总有效率为87.50%(35/40),显著高于对照组的65.00%(26/40),差异有统计学意义(P<0.05)。与对照组相比,研究组创面出血评分、创面水肿评分更低,创面愈合时间更短(P<0.05)。两组患者治疗14 d后直肠静息压(RRP)、肛管静息压(ARP)均下降,但研究组高于对照组(P<0.05)。两组治疗14 d后血清TNF-α、IL-6水平下降,且研究组低于对照组(P<0.05);两组治疗14 d后血清TGF-β1、bFGF水平升高,且研究组高于对照组(P<0.05)。两组不良反应发生率比较无差异(P>0.05)。结论:加味苦参汤联合紫归解毒膏治疗肛瘘术后患者,可促进创面尽快愈合,改善患者肛肠动力学及血清TNF-α、IL-6、TGF-β1、bFGF水平,且不增加不良反应发生率,疗效较好。     

外源性VEGF促进大鼠Ⅱ度烫伤创面中晚期愈合

目的探究Ⅱ度烫伤时外源性血管内皮生长因子(vascular endothelial growth factor,VEGF)对皮肤愈合及其对表皮干细胞(epidermal stem cells,ESCs)迁移、分化的影响方法健康Wistar大鼠随机分为VEGF组、空白对照组、阿西替尼(Axitinib,VEGF抑制剂)组。采用水浴烫伤法制备Ⅱ度烫伤模型,分别以0.2μg/ml VEGF、PBS溶液和10μg/ml阿西替尼处理各组创面,各组均治疗7d,从烫伤至创面愈合分别在第2d、8d、14d及21d测量创面愈合情况,并取创面组织作组织学检测,运用免疫组化技术检测ECSs的分布及数量。结果①创面愈合率:烫伤后21d VEGF组>对照组>阿西替尼组;②愈合速度:烫伤后1-7d空白对照组>阿西替尼组>VEGF组,其后VEGF组愈合速度逐渐加快,第14d开始愈合速度表现为VEGF组>空白对照组>阿西替尼组;③组织学变化:烫伤后8-21d,VEGF组表皮细胞增殖明显,表皮修复和毛囊再生迅速,均早于空白对照组及阿西替尼组。④ECSs阳性细胞率变化:烫伤后第8-14dVEGF组ECSs阳性细胞率明显高于空白对照组和阿西替尼。结论Ⅱ度烫伤时,外源性VEGF在愈合中晚期加快愈合速度使愈合时间明显缩短,并且促进毛囊汗腺的再生使修复后的创面在外观、功能与正常皮肤相近,有助于提高全层皮肤创面的愈合质量。     

Adipose tissue‐derived mesenchymal stem cells and keratinocytes co‐culture on gelatin/chitosan/β‐glycerol phosphate nanoscaffold in skin regeneration

Using cell‐based engineered skin is an emerging strategy for treating difficult‐to‐heal wounds. To date, much endeavor has been devoted to the fabrication of appropriate scaffolds with suitable biomechanical properties to support cell viability and growth in the microenvironment of a wound. The aim of this research was to assess the impact of adipose tissue‐derived mesenchymal stem cells (AD‐MSCs) and keratinocytes on gelatin/chitosan/β‐glycerol phosphate (GCGP) nanoscaffold in full‐thickness excisional skin wound healing of rats. For this purpose, AD‐MSCs and keratinocytes were isolated from rats and GCGP nanoscaffolds were electrospun. Through an in vivo study, the percentage of wound closure was assessed on days 7, 14, and 21 after wound induction. Samples were taken from the wound sites in order to evaluate the density of collagen fibers and vessels at 7 and 14 days. Moreover, sampling was done on days 7 and 14 from wound sites to assess the density of collagen fibers and vessels. The wound closure rate was significantly increased in the keratinocytes‐AD‐MSCs‐scaffold (KMS) group compared with other groups. The expressions of vascular endothelial growth factor, collagen type 1, and CD34 were also significantly higher in the KMS group compared with the other groups. These results suggest that the combination of AD‐MSCs and keratinocytes seeded onto GCGP nanoscaffold provides a promising treatment for wound healing.     

Chitosan film containing fucoidan as a wound dressing for dermal burn healing: Preparation and in vitro/in vivo evaluation

The aim of this study was to develop chitosan film containing fucoidan and to investigate its suitability for the treatment of dermal burns on rabbits. Porous films, thickness between 29.7 and 269.0 μm, were obtained by the solvent dropping method. Water vapor permeability (3.3–16.6/0.1 g), the swelling (0.67–1.77 g/g), tensile strength (7.1–45.8 N), and bioadhesion (0.076–1.771 mJ/cm²) of the films were determined. The thinnest films were obtained with the lowest chitosan concentration (P<.05). The water absorption capacity of the films sharply increased with the freeze-drying technique. The film having the thickness of 29.7 μm showed the highest amount of moisture permeability (16.6 g/0.1 g). Higher chitosan concentration significantly increased tensile strength of the films (P<.05). Using higher concentration of lactic acid made films more elastic and applicable, and these films were selected for in vivo studies. Seven adult male New Zealand white rabbits were used for the evaluation of the films on superficial dermal burns. Biopsy samples were taken at 7, 14, and 21 days after wounding, and each wound site was examined macroscopically and histopathologically. After 7 days treatment, fibroplasia and scar were observed on wounds treated with fucoidan-chitosan film. The best regenerated dermal papillary formation, best reepithelization, and the fastest closure of wounds were found in the fucoidan-chitosan film treatment group after 14 days compared with other treatment and control groups. It can be concluded that fucoidan-chitosan films might be a potential treatment system for dermal burns and that changing formulation variables can modulate the characterizations of the films. Published: May 24, 2007     

Changes in albumin precursor and heat shock protein 70 expression and their potential role in response to corneal epithelial wound repair

Many proteins displayed differential expression (either up- or down-regulation) when proteome of migrating and non-migrating epithelium was assessed using 2-DE and ESI-Q-TOF MS/MS. From the up-regulated set, we have identified for the first time a 69-kDa albumin precursor protein with four peptides sequences and 70-kDa heat shock protein (hsp70) with one peptide in the active phase of cell migration (48 h) during the healing process. Western blot analysis was used to further characterize these proteins at different phases (24, 48 and 72 h) of healing. An increase in the mRNA expression (measured using RT-PCR) in the active migration phase (48 h) for albumin precursor and hsp70 was also observed. Furthermore, co-immunoprecipitation studies with anti-albumin precursor and anti-hsp70 antibodies, followed by immunoblotting with anti-fibronectin antibody demonstrated a novel and biologically relevant interaction between albumin precursor protein and fibronectin in corneal epithelial wound healing but not with hsp70. The increased gene and protein expression of albumin and hsp70 during the active phase of cell migration (48 h) in the corneal epithelium suggests their possible role in corneal wound healing. These findings may have broader implications for developing therapeutic strategies for treating wound healing disorders.     

A rigorous method for evaluation of the 6D compliance of external fixators

External fixators are standard devices to stabilize bone fractures and their compliance aims at producing an interfragmentary motion that promotes rapid and successful healing. While evaluation of their axial compliance is a routine test, the quantification and interpretation of their full 6 × 6 compliance matrix is an extensive and delicate task. In this context, the objective of this study was to develop, validate and demonstrate the potential of a rigorous method to quantify their 6 × 6 compliance matrix. An experimental system was developed to apply six independent static forces and moments to an external fixator in the field of view of two infrared cameras quantifying the induced motion. The system was then tested with a calibration structure which compliance could be calculated analytically and numerically. Finally, the system was applied to compare three configurations of a commercial external wrist fixator. The results of the method proved to be reproducible and highly consistent with the linear elasticity theory in the physiological range of small deformations. A rigorous method for evaluation of the 6D compliance becomes therefore available for research in mechanobiology of fracture healing by external fixation.     

负压封闭引流治疗厌氧菌感染创面的临床观察

目的:观察负压封闭引流联合双氧水冲洗治疗厌氧菌感染创面的临床治疗效果。方法:收集我院收治的创面厌氧菌感染患者60例,随机分为两组。其中,对照组(30例)患者采用常规换药治疗创面厌氧菌感染,VSD组(30例)患者给予负压封闭引流并辅以双氧水冲洗治疗。观察并比较两组患者厌氧菌清除率,以及创面愈合情况。结果:VSD组创面厌氧菌感染率明显低于对照组,创面愈合效果优于对照组,差异有统计学意义(P0.01)。结论:负压封闭引流不仅能够有效控制感染创面厌氧菌生长,而且可以有效促进创面愈合,对临床具有指导意义。     

Enzyme‐assisted formation of hybrid biopolymer hydrogels incorporating active phenolic nanospheres

Advances in development of nanocomposite gels that provide localized delivery of pharmaceuticals for treatment of chronic wounds are being highly pursued. To design such materials, the use of natural polymers is recommendable due to their intrinsic biocompatibility and biodegradability. Moreover, the use of biocatalytic approaches for composite assembling is preferred compared to harsh chemical cross‐linking reagents. In this study, HRP catalyzed cross‐linking of hydrogels from aqueous solution of thiolated chitosan to in situ incorporated sonochemically synthesized epigallocatechin gallate nanospheres (EGCG NSs). The potential of the generated NSs for chronic wound treatment was evaluated by assessing their antibacterial properties and inhibitory effect on myeloperoxidase and collagenase—major enzymes of inflamed chronic wounds. The EGCG NSs displayed better antibacterial and antienzymatic properties compared to the EGCG in solution. Also, the NSs were incorporated into hydrogels without affecting their integrity and were released intact in a sustained manner (during 6 days). The cytotoxicity assay confirmed the compatibility of the hybrid material with human fibroblasts that suffered less than 10% decrease in viability during 24 h. Release of functional phenolic NSs and good compatibility of the composite hydrogel with cells suggested its potential application in chronic wound management.