Chondrocytes from congenital microtia possess an inferior capacity for in vivo cartilage regeneration to healthy ear chondrocytes

The remnant auricular cartilage from microtia has become a valuable cell source for ear regeneration. It is important to clarify the issue of whether the genetically defective microtia chondrocytes could engineer cartilage tissue comparable to healthy ear chondrocytes. In the current study, the histology and cell yield of native microtia and normal ear cartilage were investigated, and the biological characteristics of derived chondrocytes examined, including proliferation, chondrogenic phenotype and cell migration. Furthermore, the in vivo cartilage‐forming capacity of passaged microtia and normal auricular chondrocytes were systematically compared by seeding them onto polyglycolic acid/polylactic acid scaffold to generate tissue engineered cartilage in nude mice. Through histological examinations and quantitative analysis of glycosaminoglycan, Young's modulus, and the expression of cartilage‐related genes, it was found that microtia chondrocytes had a slower dedifferentiation rate with the decreased expression of stemness‐related genes, and weaker migration ability than normal ear chondrocytes, and the microtia chondrocytes‐engineered cartilage was biochemically and biomechanically inferior to that constructed using normal ear chondrocytes. This study provides valuable information for the clinical application of the chondrocytes derived from congenital microtia to engineer cartilage. Copyright © 2016 John Wiley & Sons, Ltd.     

Biomaterial characterization of off‐the‐shelf decellularized porcine pericardial tissue for use in prosthetic valvular applications

Fixed pericardial tissue is commonly used for commercially available xenograft valve implants, and has proven durability, but lacks the capability to remodel and grow. Decellularized porcine pericardial tissue has the promise to outperform fixed tissue and remodel, but the decellularization process has been shown to damage the collagen structure and reduce mechanical integrity of the tissue. Therefore, a comparison of uniaxial tensile properties was performed on decellularized, decellularized‐sterilized, fixed, and native porcine pericardial tissue versus native valve leaflet cusps. The results of non‐parametric analysis showed statistically significant differences (p < .05) between the stiffness of decellularized versus native pericardium and native cusps as well as fixed tissue, respectively; however, decellularized tissue showed large increases in elastic properties. Porosity testing of the tissues showed no statistical difference between decellularized and decell‐sterilized tissue compared with native cusps (p > .05). Scanning electron microscopy confirmed that valvular endothelial and interstitial cells colonized the decellularized pericardial surface when seeded and grown for 30 days in static culture. Collagen assays and transmission electron microscopy analysis showed limited reductions in collagen with processing; yet glycosaminoglycan assays showed great reductions in the processed pericardium relative to native cusps. Decellularized pericardium had comparatively low mechanical properties among the groups studied; yet the stiffness was comparatively similar to the native cusps and demonstrated a lack of cytotoxicity. Suture retention, accelerated wear, and hydrodynamic testing of prototype decellularized and decell‐sterilized valves showed positive functionality. Sterilized tissue could mimic valvular mechanical environment in vitro, therefore making it a viable potential candidate for off‐the‐shelf tissue‐engineered valvular applications.     

关节软骨修复与相关细胞因子的作用

背景：关节软骨损伤后几乎不能完全修复,在生理负荷下容易发生退行性改变,最终发展成骨性关节炎。利用细胞生长因子构建组织工程化软骨,修复重建受损关节软骨,为骨关节软骨疾病的治疗开辟了新的途径。目的：全面了解细胞凶子特性与正常关节软骨相似的组织工程软骨的构建,明确目前细胞因子促进软骨分化修复的研究进展。方法：电子检索中Ⅲ生物医学文献数据库和计算机Medline数据库1994／2009收录的关节软骨修复与相关细胞因子相关综述和论文报告,并分析其研究进展。结果与结论：共纳入软骨细胞因子相关文献29篇。关节软骨损伤后的修复非常有限,其对创伤、炎症的反应是由软骨细胞、滑膜组织分泌或关节液中含有的细胞因子所介导的。软骨细胞基质中的生长因子,通过不同的细胞信号通路使基因表达启动或关闭,在软骨生长和分化中发挥重要作用,同时软骨细胞周围环境因素也影响调控诱导分化的结果。     

Acute effects of resistance training on cytokines and osteoprotegerin in women with metabolic syndrome

Chronic inflammation has been identified as an important component of metabolic syndrome (MetS). Inhibition of the inflammatory mediator signals is a promising strategy against insulin resistance, atherosclerosis and other problems associated with MetS. Regular exercise decreases the components associated with MetS, including inflammatory cytokines. However, the relationship between an acute resistance training (RT) session, cytokine levels and MetS is unclear. Therefore, the aim was to evaluate the effects of a single bout of acute RT on tumour necrosis factor (TNF‐α), interleukins (IL) IL‐1a, IL‐1β, IL‐12, IL‐6, IL‐10 and osteoprotegerin (OPG) in women with MetS. Twenty‐four women were divided into 2 groups: metabolic syndrome (MetS) and non‐metabolic syndrome (Non‐MetS). After the familiarization and testing for 1 repetition maximum (1RM), participants completed 3 sets of 10 repetitions in the following exercises: machine leg press, leg extension, leg curl, chest press, lat front pull‐down and machine shoulder press with 60% of 1RM followed by 15 repetitions of abdominal crunches. A rest interval of 1 min was allowed between sets and exercises. Plasma TNF‐α, IL‐1a, IL‐1β, IL‐12, IL‐6, IL‐10 and OPG were measured before, immediately post and 60 min after RT. MetS group showed significantly higher concentrations of IL‐1β (P = 0·024) and IL‐6 (P = 0·049) and a trend for higher TNF‐α values (P = 0·092) compared with Non‐MetS. There was no group × time interactions after the RT session on the measured cytokines and osteoprotegerin. In conclusion, acute RT session induced no additional increase in pro‐inflammatory cytokines nor a decrease in anti‐inflammatory cytokines and OPG in women with MetS.     

A comparison study of different decellularization treatments on bovine articular cartilage

Previous researches have emphasized on suitability of decellularized tissues for regenerative applications. The decellularization of cartilage tissue has always been a challenge as the final product must be balanced in both immunogenic residue and mechanical properties. This study was designed to compare and optimize the efficacy of the most common chemical decellularization treatments on articular cartilage. Freeze/thaw cycles, trypsin, ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), and Triton‐X 100 were used at various concentrations and time durations for decellularization of bovine distal femoral joint cartilage samples. Histological staining, scanning electron microscopy, DNA quantification, compressive strength test, and Fourier‐transform infrared spectroscopy were performed for evaluation of the decellularized cartilage samples. Treatment with 0.05% trypsin/EDTA for 1 day followed by 3% SDS for 2 days and 3% Triton X‐100 for another 2 days resulted in significant reduction in DNA content and simultaneous maintenance of mechanical properties. Seeding the human adipose‐derived stem cells onto the decellularized cartilage confirmed its biocompatibility. According to our findings, an optimized physiochemical decellularization method can yield in a nonimmunogenic biomechanically compatible decellularized tissue for cartilage regeneration application.     

Cytokine and chemokine regulation of venous thromboembolism

Morbidity and mortality from venous thromboembolism (VTE), which refers to deep vein thrombosis and pulmonary embolism, have a substantial effect on the global burden of disease. The field of venous thrombosis research has been dramatically changed over the past 10 years with the improvement of animal models that shed some light on the interaction between inflammation and thrombosis. Important recent advances provided evidence of the implication of the innate immune system in venous thrombosis. In this review, we highlighted the cytokines and chemokines that regulate mechanisms of thrombus formation and resolution. Cytokines are pleiotropic, redundant, and multifunctional endogenous mediators orchestrating the inflammatory responses leading to thrombus formation or resolution. The use of experimental models has revealed the pro‐thrombotic activity of some cytokines including interferon‐γ, interleukin (IL)‐6, chemokine ligand 2, IL‐17A, IL‐9, IL‐1β, and transforming growth factor‐β. Other cytokines such as IL‐10, tumor necrosis factor‐α, and IL‐8 appear to promote thrombus resolution in late phase of venous thromboembolism. The purpose of this review is to bring together the current knowledge regarding the cytokines and chemokines that have been involved in thrombosis formation and resolution. We postulate that an imbalance between pro‐thrombotic and anti‐thrombotic cytokines/chemokines may be involved in the pathophysiology of VTE. However, in‐depth basic and clinical research in venous thrombosis is still require to fully understand the precise mechanism of action of these cytokines.     

Auricular cartilage repair using cryogel scaffolds loaded with BMP‐7‐expressing primary chondrocytes

The loss of cartilage tissue due to trauma, tumour surgery or congenital defects, such as microtia and anotia, is one of the major concerns in head and neck surgery. Recently tissue‐engineering approaches, including gene delivery, have been proposed for the regeneration of cartilage tissue. In this study, primary chondrocytes were genetically modified with plasmid‐encoding bone morphogenetic protein‐7 (BMP‐7) via the commercially available non‐viral Turbofect vector, with the aim of bringing ex vivo transfected chondrocytes to resynthesize BMP‐7 in vitro as they would in vivo. Genetically modified cells were implanted into gelatin–oxidized dextran scaffolds and cartilage tissue formation was investigated in 15 × 15 mm auricular cartilage defects in vivo in 48 New Zealand (NZ) white rabbits for 4 months. The results were evaluated via histology and early gene expression. Early gene expression results indicated a strong effect of exogenous BMP‐7 on matrix synthesis and chondrocyte growth. In addition, histological analysis results exhibited significantly better cartilage healing with BMP‐7‐modified (transfected) cells than in the non‐modified (non‐transfected) group and as well as the control. Copyright © 2012 John Wiley & Sons, Ltd.     

Polymerized laminin incorporation into alginate‐based microcapsules reduces pericapsular overgrowth and inflammation

Cell encapsulation coats cells with an artificial membrane to preserve their physical and functional integrity. Different approaches try to develop more functional and biocompatible materials to avoid cell loss after transplantation due to inflammatory reaction, one of the main causes for graft failure. In this study, the LN‐Biodritin biomaterial, based on alginate, chondroitin sulfate, and laminin, previously developed by our group, was further improved by replacing laminin by polylaminin, an artificial laminin polymer with anti‐inflammatory properties, generating the new biomaterial polyLN‐Biodritin. Capsules containing polylaminin are stable, do not induce macrophage activation in vitro, and are also able to prevent macrophage activation by encapsulated human pancreatic islets in vitro, preserving their glucose‐stimulated insulin secretion potential. In addition, when empty capsules containing polylaminin were implanted into immunocompetent mice, the inflammatory response towards the implant was attenuated, when compared with capsules without polylaminin. The results indicate that polylaminin incorporation leads to lower levels of pericapsular growth on the capsules surface, lower infiltration of cells into the peritoneal cavity, and lower production of proinflammatory cytokines, both at the implant site (interleukin‐12p70 (IL‐12p70), tumor necrosis factor‐α (TNF‐α), monocyte chemotactic protein‐1 (MCP‐1), and interferon‐γ (IFN‐γ)) and systemically (IL‐12p70 and TNF‐α). Therefore, polylaminin incorporation into the microcapsules polymer attenuates the host posttransplantation immune response against implanted microcapsules, being likely to favor maintenance of engrafted encapsulated cells.     

Microencapsulated rabbit adipose stem cells initiate tissue regeneration in a rabbit ear defect model

Cell‐based tissue engineering can promote cartilage tissue regeneration, but cell retention in the implant site post‐delivery is problematic. Alginate microbeads containing adipose stem cells (ASCs) pretreated with chondrogenic media have been used successfully to regenerate hyaline cartilage in critical size defects in rat xiphoid suggesting that they may be used to treat defects in elastic cartilages such as the ear. To test this, we used microbeads made with low viscosity, high mannuronate medical grade alginate using a high electrostatic potential, and a calcium cross linking solution containing glucose. Microbeads containing rabbit ASCs (rbASCs) were implanted bilaterally in 3 mm critical size midcartilage ear defects of six skeletally mature male New Zealand White rabbits (empty defect; microbeads without cells; microbeads with cells; degradable microbeads with cells; and autograft). Twelve weeks post‐implantation, regeneration was assessed by microCT and histology. Microencapsulated rbASCs cultured in chondrogenic media expressed mRNAs for aggrecan, Type II collagen, and Type X collagen. Histologically, empty defects contained fibrous tissue; microbeads without cells were still present in defects and were surrounded by fibrous tissue; nondegradable beads with rbASCs initiated cartilage regeneration; degradable microbeads with cells produced immature bone‐like tissue, also demonstrated by microCT; and autografts appeared as normal auricular cartilage but were not fully integrated with the tissue surrounding the defect. Elastin, the hallmark of auricular cartilage, was not evident in the neocartilage. This delivery system offers the potential for regeneration of auricular cartilage, but vascularity of the treatment site and use of factors that induce elastin must be considered.     

Blocking of cytokines signalling attenuates evoked and spontaneous neuropathic pain behaviours in the paclitaxel rat model of chemotherapy‐induced neuropathy

Background

Chemotherapy‐induced peripheral neuropathic pain (CIPNP) is a serious dose‐limiting neurotoxic effect of cancer drug treatment. The underlying mechanism(s) of this debilitating condition, which lacks effective drug treatment, is incompletely understood. However, neural–immune interactions, involving increased expression and release of cytokines, are believed to be involved. Here, we examined, in the paclitaxel rat model of CIPNP, whether plasma levels of 24 cytokines/chemokines change after paclitaxel treatment, and whether blocking of signalling of some of those cytokines would reverse/attenuate behavioural signs of CIPNP.

Methods

To achieve these objectives luminex, pharmacological and behavioural experiments were performed on male Wistar rats (250–300 g) 31 days after the last injection of paclitaxel (1 mg/kg, i.p. on four alternate days) as well as on control (vehicle‐treated) rats.

Results

Compared with control rats, plasma levels of IL‐1α, IL‐1β, IL‐6, TNF‐α, INF‐γ and MCP‐1 were significantly upregulated in paclitaxel‐treated rats. Blocking of TNF‐α signalling with etanercept (2 mg/kg, i.p.) or IL‐1β with IL‐1 receptor antagonist (IL‐1ra; 3 mg/kg, i.p.), significantly attenuated established mechanical and cold hypersensitivity as well as spontaneous pain behaviour (spontaneous foot lifting) 24 and 48 h postdrug treatment. Pharmacological blockade of MCP‐1/CCL2 signalling with a highly selective CCR2 receptor antagonist (S504393, 5 mg/kg, i.p.) also significantly reduced evoked, but not spontaneous, pain behaviours of CIPNP in paclitaxel‐treated rats at the same time points.

Conclusions

The findings support the notion that cytokines/chemokines, particularly TNF‐α, IL‐1 and MCP‐1, are involved in the pathophysiology of CIPNP and suggest that strategies that target their inhibition may be effective in treating CIPNP.

Significance

This study demonstrates that paclitaxel‐treated rats exhibit, in addition to indices of mechanical and cold hypersensitivity, a behavioural sign of spontaneous pain, the principal compliant of patients with neuropathic pain. This was accompanied by upregulation in plasma levels of key cytokines/chemokines (IL‐1α, IL‐1β, IL‐6, TNF‐α, INF‐γ and MCP‐1) 31 days post‐treatment. However, it is noteworthy that cytokine release, rather than nerve injury per se, may be causative of NP in this model of CIPNP. Nevertheless, our findings that pharmacological blockade of TNF‐α, IL‐1β and MCP‐1 attenuated both evoked and spontaneous pain suggest that strategies that target inhibition of these cytokines may be effective in treating CIPNP.     

Successful recellularization of human tendon scaffolds using adipose‐derived mesenchymal stem cells and collagen gel

The major goal of regenerative medicine is to determine experimental techniques that take maximal advantage of reparative processes that occur naturally in the animal body. Injection of mesenchymal stem cells into the core of a damaged tendon represents such an approach. Decellularization of native tendons as potential targets and seeding protocols are currently under investigation. The aim of our study was to manufacture a recellularized biocompatible scaffold from cadaveric tissue for use in total or partial tendon injuries. Results showed that it was possible to introduce proliferating cells into the core of a decellularized tendon to treat the scaffold with a collagen gel. The method was effective in maintaining scaffold extracellular matrix and for expressing collagen type I and cartilage oligomeric matrix protein by injecting mesenchymal stem cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Sequential hydrophile and lipophile solubilization as an efficient method for decellularization of porcine aortic valve leaflets: Structure,mechanical property and biocompatibility study

Antigenicity of xenogeneic tissues is the major obstacle to increased use of these materials in clinical medicine. Residual xenoantigens in decellularized tissue elicit the immune response after implantation, causing graft failure. With this in mind, the potential use is proposed of three protein solubilization‐based protocols for porcine aortic valve leaflets decellularization. It was demonstrated that hydrophile solubilization alone achieved incomplete decellularization; lipophile solubilization alone (LSA) completely removed all cells and two most critical xenoantigens – galactose‐α(1,3)‐galactose (α‐Gal) and major histocompatibility complex I (MHC I) – but caused severe alterations of the structure and mechanical properties; sequential hydrophile and lipophile solubilization (SHLS) resulted in a complete removal of cells, α‐Gal and MHC I, and good preservation of the structure and mechanical properties. In contrast, a previously reported method using Triton X‐100, sodium deoxycholate and IGEPAL CA‐630 resulted in a complete removal of all cells and MHC I, but with remaining α‐Gal epitope. LSA‐ and SHLS‐treated leaflets showed significantly reduced leucocyte activation (polymorphonuclear elastase) upon interaction with human blood in vitro. When implanted subdermally in rats for 6 weeks, LSA‐ or SHLS‐treated leaflets were presented with more biocompatible implants and all four decellularized leaflets were highly resistant to calcification. These findings illustrate that the SHLS protocol could be considered as a promising decellularization method for the decellularization of xenogeneic tissues in tissue engineering and regenerative medicine. Copyright © 2016 John Wiley & Sons, Ltd.     

自体软骨及生物材料植入物充填单侧唇裂继发鼻畸形

背景：单侧唇裂一期修复术后往往继发不同程度的鼻畸形,根据不同畸形的特点,选择合适的自体软骨及生物材料可有效加强和恢复鼻部支架结构、矫正鼻部畸形。目的：探讨不同植入材料在单侧唇裂继发鼻畸形整复中的应用及效果。方法：纳入单侧唇裂修补36例,表现为不同程度的鼻部畸形,在行唇部相关手术的同时,对移位的鼻软骨及周围软组织进行有效松解及复位,并根据不同畸形的特点,应用自体鼻中隔软骨、耳甲软骨、肋软骨及Medpor外科种植体对患侧鼻翼基底部、鼻翼软骨、前鼻棘、鼻小柱及鼻尖部进行充填以加强和恢复鼻部骨及软骨支架结构。结果与结论：所有病例鼻部畸形明显矫正,患侧鼻翼基底部抬升,双侧鼻孔、鼻穹窿部基本对称,鼻小柱延长、偏斜纠正,鼻尖部形态满意。自体软骨供区无明显畸形出现。随访1个月~3年,2例患侧鼻翼较术后塌陷、鼻翼稍低平、鼻孔略宽于健侧,其余病例鼻外形维持良好,植入物无排斥反应、移位及外露。提示,在唇裂继发鼻畸形整复手术中,应用植入材料充填可有效加强和恢复鼻部支架结构,明显改善鼻部畸形,术中应根据不同畸形的特点选择合适的植入充填材料。     

Cytokine responses,microbial aetiology and short‐term outcome in community‐acquired pneumonia

Background

The inflammatory response to community‐acquired pneumonia (CAP) is orchestrated through activation of cytokine networks and the complement system. We examined the association of multiple cytokines and the terminal complement complex (TCC) with microbial aetiology, disease severity and short‐term outcome.

Materials and methods

Plasma levels of 27 cytokines and TCC were analysed in blood samples obtained at hospital admission, clinical stabilization and 6‐week follow‐up from 247 hospitalized adults with CAP. Fourteen mediators were included in final analyses. Adverse short‐term outcome was defined as intensive care unit (ICU) admission and 30‐day mortality.

Results

Cytokine and TCC levels were dynamic in the clinical course of CAP, with highest levels seen at admission for most mediators. Admission levels of cytokines and TCC did not differ between groups of microbial aetiology. High admission levels of IL‐6 (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.18‐1.84, P = .001), IL‐8 (OR 1.79, 95% CI 1.26‐2.55, P = .001) and MIP‐1β (OR 2.28, 95% CI 1.36‐3.81, P = .002) were associated with a CURB‐65 severity score of ≥3, while IL‐6 (OR 1.37, 95% CI 1.07‐1.74, P = .011) and MIP‐1β (OR 1.86, 95% CI 1.03‐3.36, P = .040) were associated with a high risk of an adverse short‐term outcome.

Conclusions

In this CAP cohort, admission levels of IL‐6, IL‐8 and MIP‐1β were associated with disease severity and/or adverse short‐term outcome. Still, for most mediators, only nonsignificant variations in inflammatory responses were observed for groups of microbial aetiology, disease severity and short‐term outcome.     

Human gingival mesenchymal stem cells pretreated with vesicular moringin nanostructures as a new therapeutic approach in a mouse model of spinal cord injury

Spinal cord injury (SCI) is a neurological disorder that arises from a primary acute mechanical lesion, followed by a pathophysiological cascade of events that leads to further spinal cord tissue damage. Several preclinical and clinical studies have highlighted the ability of stem cell therapy to improve long‐term functional recovery in SCI. Previously, we demonstrated that moringin (MOR) treatment accelerates the differentiation process in mesenchymal stem cells inducing an early up‐regulation of neural development associated genes. In the present study, we investigated the anti‐inflammatory, anti‐apoptotic, and regenerative effects of gingival mesenchymal stem cells (GMSCs) pretreated with nanostructured liposomes enriched with MOR in an animal model of SCI. SCI was produced by extradural compression of the spinal cord at levels T6–T7 in ICR (CD‐1) mice. Animals were randomly assigned to the following groups: Sham, SCI, SCI + GMSCs (1 × 10⁶ cell/i.v.), SCI + MOR‐GMSCs (1 × 10⁶ cell/i.v.). Our data show that MOR‐treated GMSCs exert anti‐inflammatory and anti‐apoptotic activities. In particular, MOR‐treated GMSCs are able to reduce the spinal cord levels of COX‐2, GFAP, and inflammatory cytokines IL‐1β and IL‐6 and to restore spinal cord normal morphology. Also, MOR‐treated GMSCs influenced the apoptotic pathway, by reducing Bax, caspase 3, and caspase 9 expressions.     

The development and implantation of a biologically derived allograft scaffold

Biologically derived scaffolds are becoming viable treatment options for tissue/organ repair and regeneration. A continuing hurdle is the need for a functional blood supply to and from the implanted scaffold. We have addressed this problem by constructing an acellular ileal scaffold with an attached vascular network suitable for implantation and immediate reperfusion with the host's blood. Using a vascular perfusion approach, a segment of porcine ileum up to 30 cm long, together with its attached vasculature, was decellularized as a single entity. The quality of the decellularized scaffold was assessed histologically and using molecular tools. To establish vascular perfusion potentials of the scaffold, a right‐sided nephrectomy and end‐to‐end anastomosis of the decellularized scaffold's vasculature to a renal artery and vein were performed in a pig of similar size to the donor animal. Lengths of ileal scaffold, together with its attached vasculature, were successfully decellularized, with no evidence of intact cells/nuclear material or collagen degradation. The scaffold's decellularized vascular network demonstrated optimum perfusion at 1, 2 and 24 h post‐implantation and the mesenteric arcade remained patent throughout the assessment. The 1, 2 and 24 h explanted scaffolds demonstrated signs of cellular attachment, with cells positive for CD68 and CD133 on the vascular luminal aspect. It is possible to decellularize clinically relevant lengths of small intestine, together with the associated vasculature, as a single segment. The functional vascular network may represent a route for recellularization for future regeneration of bowel tissue for patients with short bowel syndrome. Copyright © 2013 John Wiley & Sons, Ltd.     

Contrary response of porcine articular cartilage below and over 1000 s−1

BackgroundKnee joints experience excessive loads quite frequently during sports activities, and these shocks could accelerate progressive degeneration in articular cartilage.MethodsQuasi-static and dynamic response of porcine knee articular cartilages were investigated in this research. Split Hopkinson Pressure Bars (SHPB) were utilized to examine the articular cartilage properties at strain rates between 0.01–2000 s⁻¹.FindingsThe results showed that strain rate is an important factor for articular cartilages, distinctively divided into above and below 1000 s⁻¹. The articular cartilages exhibit a strain hardening phenomenon when shock loaded at strain rates under 1000 s⁻¹. When loaded at strain rates over 1000 s⁻¹, their ultimate strength and elastic modulus decreased with increasing strain rates.InterpretationThe biphasic structure of the cartilage explained the change of modulus. At the lower strain rates, fibers realigned and solidified the structure, while at higher strain rates, there is not enough time for the tissue fluid to move inside the cartilage, leading to a reduction in the deformability of the specimen and raising of Young's modulus. The results can be utilized to provide some useful data for biomaterial and computational works in the future.     

Therapeutic effect of long‐interval repeated intravenous administration of human umbilical cord blood‐derived mesenchymal stem cells in DBA/1 mice with collagen‐induced arthritis

Rheumatoid arthritis (RA) is a common inflammatory chronic disease. It has been reported that mesenchymal stem cells (MSCs) have the effect of immune suppression in collagen‐induced arthritis (CIA) mice model. However, the in vivo therapeutic effect from the long‐interval repeated intravenous administration of human umbilical cord blood‐derived (hUCB)‐MSCs had not been investigated in CIA mice model. This study was undertaken to investigate the effects of long‐interval repeated intravenous administration of hUCB‐MSCs at different doses in CIA mice model. Mice were intravenously injected with three different doses of hUCB‐MSCs once every 2 weeks for three times. RA severity was assessed by clinical joint score and histologic analysis including hematoxylin and eosin staining, safranin‐O staining, and toluidine blue staining. We used real‐time polymerase chain reaction and flow cytometry to quantify differences in inflammatory cytokines and Tregs. Mice treated with hUCB‐MSCs showed significant improvement in clinical joint score. Histologic analysis revealed that hUCB‐MSCs definitely reduced joint inflammation, cartilage damage, and formation of pannus in multimedium and multihigh groups. These hUCB‐MSCs also significantly decreased IL‐1 beta protein levels in multimedium and multihigh groups and IL‐6 protein levels in all hUCB‐MSCs‐treated groups. Furthermore, mRNA levels of IL‐1 beta and IL‐6 were decreased significantly in all hUCB‐MSCs‐treated groups, whereas the expression of anti‐inflammatory cytokine IL‐10 was increased in the multihigh group. Tregs known as suppressor T cells were also significantly increased in the multihigh group. Our findings suggest that long‐interval repeated intravenous administration of hUCB‐MSCs has therapeutic effects by improving symptoms of RA in CIA mice model in a dose‐dependent manner.     

脱钙骨基质与骨髓间充质干细胞共培养关节腔内的成软骨活性

背景：将骨髓间充质干细胞附着到支架材料上再植入关节软骨缺损处,细胞不但不消失,而且可形成新的软骨。目的：观察同种异体脱钙骨基质与骨髓间充质干细胞共培养在关节内的成软骨活性。方法：在54只青紫蓝兔单侧膝关节制作关节软骨全层缺损模型,随机分组：实验组在缺损处植入自体骨髓间充质干细胞与同种异体脱钙骨基质复合物,对照组缺损处仅植入同种异体脱钙骨基质,空白对照组未植入任何物质。结果与结论：植入后12周,实验组缺损处修复组织呈软骨样,表面光滑平坦,与周围软骨整合的软骨细胞更为成熟,修复组织与软骨下骨结合牢固;修复组织的细胞为透明软骨样细胞,柱状排列,Ⅱ型胶原染色阳性,与周围软骨及软骨下骨整合良好,且实验组组织学评分优于对照组和空白对照组（P〈0.01）。对照组缺损处修复组织呈纤维样,与周围软骨未结合,空白对照组缺损区无修复组织,两组均无Ⅱ型胶原染色阳性表达。表明同种异体脱钙骨基质与骨髓间充质干细胞共培养后植入膝关节可形成软骨样组织,有效修复关节软骨缺损。     

Amniotic mesenchymal stem cells mitigate osteoarthritis progression in a synovial macrophage‐mediated in vitro explant coculture model

Osteoarthritis (OA) is a disease of the synovial joint marked by chronic, low‐grade inflammation leading to cartilage destruction. Regenerative medicine strategies for mitigating OA progression and/or promoting cartilage regeneration must be assessed using models that mimic the hallmarks of OA. More specifically, these models should maintain synovial macrophage phenotype in their native micro‐environment. Herein, an in vitro coculture model of patient‐matched human OA cartilage and synovium was assessed for viability, macrophage phenotype, and progressive cartilage destruction in the presence of an inflammatory milieu. Additionally, the influence of synovial macrophages and their polarization within the model was defined using depletion studies. Finally, the model was used to compare the ability of human amniotic stem cells (hAMSCs) and human adipose stem cells (hADSCs) to mitigate OA progression. OA cocultures demonstrated progressive and significant reductions in chondrocyte viability and cartilage glycosaminoglycan content within a proinflammatory environment. Selective depletion of synovial macrophages resulted in significant decreases in M1:M2 percentage ratio yielding significant reductions in concentrations of interleukin‐1 beta, matrix metalloproteinase‐13 and attenuation of cartilage damage. Finally, hAMSCs were found to be more chondroprotective versus hADSCs as indicated by significantly improved OA chondrocyte viability (89.8 ± 2.4% vs. 58.4 ± 2.4%) and cartilage glycosaminoglycan content (499.0 ± 101.9 μg/mg dry weight vs. 155.0 ± 26.3 μg/mg dry weight) and were more effective at shifting OA synovial macrophage M1:M2 ratio (1.3:1 vs. 5:1), respectively. Taken together, the coculture model mimics salient features of OA, including macrophage‐mediated cartilage destruction that was effectively abrogated by hAMSCs but not hADSCs.