Translational research of adult stem cell therapy

Congestive heart failure(CHF) secondary to chronic coronary artery disease is a major cause of morbidity and mortality world-wide. Its prevalence is increasing despite advances in medical and device therapies. Cell based therapies generating new cardiomyocytes and vessels have emerged as a promising treatment to reverse functional deterioration and prevent the progression to CHF. Functional efficacy of progenitor cells isolated from the bone marrow and the heart have been evaluated in preclinical large animal models. Furthermore, several clinical trials using autologous and allogeneic stem cells and progenitor cells have demonstrated their safety in humans yet their clinical relevance is inconclusive. This review will discuss the clinical therapeutic applications of three specific adult stem cells that have shown particularly promising regenerative effects in preclinical studies, bone marrow derived mesenchymal stem cell, heart derived cardiosphere-derived cell and cardiac stem cell. We will also discuss future therapeutic approaches.

Effect of alteplase thrombolysis on nerve injury and serum cytokines in patients with cerebral infarction

Objective:To study the effect of alteplase thrombolysis on nerve injury and serum cytokines in patients with cerebral infarction.Methods: Patients with acute cerebral infarction who received thrombolytic therapy in Dongfang Hospital between May 2014 and October 2016 were retrospectively analyzed, and according to the different ways of thrombolysis, they were divided into rt-Pa group and UK group who accepted alteplase and urokinase thrombolysis respectively. Serum levels of nerve injury markers, nerve cytokines and inflammatory cytokines were detected before as well as 1 d and 7 d after thrombolytic therapy.Results:1 d and 7 d after thrombolysis, serum nerve injury markers NSE, S100B, MDA and 8-OHdG as well as inflammatory cytokines IL-1β, IL-18, TNF-α and sVCAM-1 levels of both groups of patients were significantly lower than those before treatment while nerve cytokines BDNF, NGF and VEGF levels were significantly higher than those before treatment, and serum nerve injury markers NSE, S100B, MDA and 8-OHdG as well as inflammatory cytokines IL-1β, IL-18, TNF-α and sVCAM-1 levels of rt-Pa group were significantly lower than those of UK group while nerve cytokines BDNF, NGF and VEGF levels were significantly higher than those of UK group. Conclusion: Alteplase thrombolysis for acute cerebral infarction can reduce nerve injury, improve neurotrophic state, and inhibit inflammatory response.

Generating 3D-cultured organoids for pre-clinical modeling and treatment of degenerative joint disease

Dear Editor,Human cell-based and personalized in vitro cartilage models are urgently needed for osteoarthritis treatment in pre-clinical regenerative medicine development.Cellular self-assemblies and condensations of the appropriate stem cells could initiate the formation of transient tissue structures programmed for specific organogenesis processes.1 This recapitulation of developmental events has previously been demonstrated for the formation of cardiac,epithelial and liver organoids.However,there has been very limited progress in the development of human cartilage organoids for osteoarthritis(OA).2 Here,we describe the fabrication of functional bioengineered cartilage organoid suitable for OA treatment.Briefly,agarose microwell inserts for formation of a high number of synovial mesenchymal stromal cell(SMSC)organoids with homogeneous size distribution were created as previously described by Leijten et al.33D-cultured SMSC organoids were generated and phenotypically analyzed for potential applications in OA modeling and treatment(Fig.1a).

Gene-knockout by iSTOP enables rapid reproductive disease modeling and phenotyping in germ cells of the founder generation

Cytosine base editing achieves C·G-to-T·A substitutions and can convert four codons(CAA/CAG/CGA/TGG)into STOP-codons(induction of STOP-codons,iSTOP)to knock out genes with reduced mosaicism.iSTOP enables direct phenotyping in founders’somatic cells,but it remains unknown whether this works in founders’germ cells so as to rapidly reveal novel genes for fertility.Here,we initially establish that iSTOP in mouse zygotes enables functional characterization of known genes in founders’germ cells:Cfap43-iSTOP male founders manifest expected sperm features resembling human“multiple morphological abnormalities of the flagella”syndrome(i.e.,MMAF-like features),while oocytes of Zp3-iSTOP female founders have no zona pellucida.We further illustrate iSTOP’s utility for dissecting the functions of unknown genes with Ccdc183,observing MMAF-like features and male infertility in Ccdc183-iSTOP founders,phenotypes concordant with those of Ccdc183-KO offspring.We ultimately establish that CCDC183 is essential for sperm morphogenesis through regulating the assembly of outer dynein arms and participating in the intra-flagellar transport.Our study demonstrates iSTOP as an efficient tool for direct reproductive disease modeling and phenotyping in germ cells of the founder generation,and rapidly reveals the essentiality of Ccdc183 in fertility,thus providing a time-saving approach for validating genetic defects(like nonsense mutations)for human infertility.

Coiled-coil domain-containing 38 is required for acrosome biogenesis and fibrous sheath assembly in mice

During spermiogenesis,haploid spermatids undergo dramatic morphological changes to form slender sperm flagella and cap-like acrosomes,which are required for successful fertilization.Severe deformities in flagella cause a male infertility syndrome,multiple morphological abnormalities of the flagella(MMAF),while acrosomal hypoplasia in some cases leads to sub-optimal embryonic developmental potential.However,evidence regarding the occurrence of acrosomal hypoplasia in MMAF is limited.Here,we report the generation of base-edited mice knocked out for coiled-coil domain-containing 38(Ccdc38)via inducing a nonsense mutation and find that the males are infertile.The Ccdc38-KO sperm display acrosomal hypoplasia and typical MMAF phenotypes.We find that the acrosomal membrane is loosely anchored to the nucleus and fibrous sheaths are disorganized in Ccdc38-KO sperm.Further analyses reveal that Ccdc38 knockout causes a decreased level of TEKT3,a protein associated with acrosome biogenesis,in testes and an aberrant distribution of TEKT3 in sperm.We finally show that intracytoplasmic sperm injection overcomes Ccdc38-related infertility.Our study thus reveals a previously unknown role for CCDC38 in acrosome biogenesis and provides additional evidence for the occurrence of acrosomal hypoplasia in MMAF.

多囊卵巢综合征无排卵的胰岛素信号和雄激素合成的新遗传风险和代谢特征

促排卵是多囊卵巢综合征(PCOS)不孕症的一线治疗方案。卵巢对促排卵治疗的排卵应答差被认为与胰岛素抵抗和高雄激素血症相关。在一个包含1000名PCOS不孕妇女(PCOSAct)的前瞻性队列中,我们开展了一项全外显子联合靶向单核苷酸多态性(SNP)测序以及代谢组学研究。在全基因组水平找出与无排卵显著相关的常见变异和罕见突变,并通过机器学习算法构建排卵预测模型。研究发现,ZNF438基因中标记为rs2994652(p=2.47×10^(-8))的常见变异和REC114基因中的一个罕见功能突变(rs182542888,p=5.79×10^(-6))与促排卵治疗失败显著相关。携带rs2994652 A等位基因和REC114 p.Val101Leu(rs182542888)的PCOS不孕妇女进行促排卵治疗的总排卵率更低(分别为比值比(OR)=1.96,95%置信区间(CI)[1.55~2.49];OR=11.52,95%CI[3.08~43.05]),出现排卵的间隔时间更长(平均56.7天vs.49.0天,p<0.001;78.1天vs.68.6天,p=0.014)。对于rs2994652突变者,L-苯丙氨酸水平升高并与胰岛素抵抗稳态模型(HOMA-IR)指数(r=0.22,p=0.05)和空腹血糖(r=0.33,p=0.003)呈正相关;对于rs182542888突变者,花生四烯酸代谢产物水平下降并与升高的抗苗勒管激素(r=-0.51,p=0.01)和总睾酮(r=-0.71,p=0.02)呈负相关。整合基因变异位点、代谢产物及临床特征的联合预测模型可提高对排卵的预测能力[曲线下面积(AUC)=76.7%]。ZNF438基因的一个常见变异和REC114基因的一个罕见功能突变,以及与二者相关的苯丙氨酸和花生四烯酸代谢物改变,与PCOS女性不孕症的促排卵治疗失败相关。

Accelerated fracture healing by osteogenic Ti45Nb implants through the PI3K–Akt signaling pathway

The key to managing fracture is to achieve stable internal fixation,and currently,biologically and mechanically appropriate internal fixation devices are urgently needed.With excellent biocompatibility and corrosion resistance,titanium–niobium alloys have the potential to become a new generation of internal fixation materials for fractures.However,the role and mechanism of titanium–niobium alloys on promoting fracture healing are still undefined.Therefore,in this study,we systematically evaluated the bone-enabling properties of Ti45Nb via in vivo and in vitro experiments.In vitro,we found that Ti45Nb has an excellent ability to promote MC3T3-E1 cell adhesion and proliferation without obvious cytotoxicity.Alkaline phosphatase(ALP)activity and alizarin red staining and semiquantitative analysis showed that Ti45Nb enhanced the osteogenic differentiation of MC3T3-E1 cells compared to the Ti6Al4V control.In the polymerase chain reaction experiment,the expression of osteogenic genes in the Ti45Nb group,such as ALP,osteopontin(OPN),osteocalcin(OCN),type 1 collagen(Col-1)and runt-related transcription factor-2(Runx2),was significantly higher than that in the control group.Meanwhile,in the western blot experiment,the expression of osteogenic-related proteins in the Ti45Nb group was significantly increased,and the expression of PI3K–Akt-related proteins was also higher,which indicated that Ti45Nb might promote fracture healing by activating the PI3K–Akt signaling pathway.In vivo,we found that Ti45Nb implants accelerated fracture healing compared to Ti6Al4V,and the biosafety of Ti45Nb was confirmed by histological evaluation.Furthermore,immunohistochemical staining confirmed that Ti45Nb may promote osteogenesis by upregulating the PI3K/Akt signaling pathway.Our study demonstrated that Ti45Nb exerts an excellent ability to promote fracture healing as well as enhance osteoblast differentiation by activating the PI3K/Akt signaling pathway,and its good biosafety has been confirmed,which indicates its clinical translation potential.

cGAS regulates the DNA damage response to maintain proliferative signaling in gastric cancer cells

The activation of some oncogenes promote cancer cell proliferation and growth,facilitate cancer progression and metastasis by induce DNA replication stress,even genome instability.Activation of the cyclic GMP-AMP synthase(cGAS)mediates classical DNA sensing,is involved in genome instability,and is linked to various tumor development or therapy.However,the function of cGAS in gastric cancer remains elusive.In this study,the TCGA database and retrospective immunohistochemical analyses revealed substantially high cGAS expression in gastric cancer tissues and cell lines.By employing cGAS high-expression gastric cancer cell lines,including AGS and MKN45,ectopic silencing of cGAS caused a significant reduction in the proliferation of the cells,tumor growth,and mass in xenograft mice.Mechanistically,database analysis predicted a possible involvement of cGAS in the DNA damage response(DDR),further data through cells revealed protein interactions of the cGAS and MRE11-RAD50-NBN(MRN)complex,which activated cell cycle checkpoints,even increased genome instability in gastric cancer cells,thereby contributing to gastric cancer progression and sensitivity to treatment with DNA damaging agents.Furthermore,the upregulation of cGAS significantly exacerbated the prognosis of gastric cancer patients while improving radiotherapeutic outcomes.Therefore,we concluded that cGAS is involved in gastric cancer progression by fueling genome instability,implying that intervening in the cGAS pathway could be a practicable therapeutic approach for gastric cancer.

Loss of Tet hydroxymethylase activity causes mouse embryonic stem cell differentiation bias and developmental defects

The TET family is well known for active DNA demethylation and plays important roles in regulating transcription,the epigenome and development.Nevertheless,previous studies using knockdown(KD)or knockout(KO)models to investigate the function of TET have faced challenges in distinguishing its enzymatic and nonenzymatic roles,as well as compensatory effects among TET family members,which has made the understanding of the enzymatic role of TET not accurate enough.To solve this problem,we successfully generated mice catalytically inactive for specific Tet members(Tetm/m).We observed that,compared with the reported KO mice,mutant mice exhibited distinct developmental defects,including growth retardation,sex imbalance,infertility,and perinatal lethality.Notably,Tetm/mmouse embryonic stem cells(mESCs)were successfully established but entered an impaired developmental program,demonstrating extended pluripotency and defects in ectodermal differentiation caused by abnormal DNA methylation.Intriguingly,Tet3,traditionally considered less critical for m ESCs due to its lower expression level,had a significant impact on the global hydroxymethylation,gene expression,and differentiation potential of mESCs.Notably,there were common regulatory regions between Tet1 and Tet3 in pluripotency regulation.In summary,our study provides a more accurate reference for the functional mechanism of Tet hydroxymethylase activity in mouse development and ESC pluripotency regulation.

Current Immunotherapy Strategies for Rheumatoid Arthritis:The Immunoengineering and Delivery Systems

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease accompanied by persistent multiarticular synovitis and cartilage degradation. The present clinical treatments are limited to disease-modifying anti-rheumatic drugs (DMARDs) and aims to relieve pain and control the inflammation of RA. Despite considerable advances in the research of RA, the employment of current clinical procedure is enormous, hindered by systemic side effect, frequent administration, tolerance from long-lasting administration, and high costs. Emerging immunoengineering-based strategies, such as multiple immune-active nanotechnologies via mechanism-based immunology approaches, have been developed to improve specific targeting and to reduce adverse reactions for RA treatments. Here, we review recent studies in immunoengineering for the treatment of RA. The prospect of future immunoengineering treatment for RA has also been discussed.

Transcriptome Dynamics and Cell Dialogs Between Oocytes and Granulosa Cells in Mouse Follicle Development

The development and maturation of follicles is a sophisticated and multistage process.The dynamic gene expression of oocytes and their surrounding somatic cells and the dialogs between these cells are critical to this process.In this study,we accurately classified the oocyte and follicle development into nine stages and profiled the gene expression of mouse oocytes and their surrounding granulosa cells and cumulus cells.The clustering of the transcriptomes showed the trajectories of two distinct development courses of oocytes and their surrounding somatic cells.Gene expression changes precipitously increased at Type 4 stage and drastically dropped afterward within both oocytes and granulosa cells.Moreover,the number of differentially expressed genes between oocytes and granulosa cells dramatically increased at Type 4 stage,most of which persistently passed on to the later stages.Strikingly,cell communications within and between oocytes and granulosa cells became active from Type 4 stage onward.Cell dialogs connected oocytes and granulosa cells in both unidirectional and bidirectional manners.TGFB2/3,TGFBR2/3,INHBA/B,and ACVR1/1B/2B of TGF-βsignaling pathway functioned in the follicle development.NOTCH signaling pathway regulated the development of granulosa cells.Additionally,many maternally DNA methylation-or H3K27me3-imprinted genes remained active in granulosa cells but silent in oocytes during oogenesis.Collectively,Type 4 stage is the key turning point when significant transcription changes diverge the fate of oocytes and granulosa cells,and the cell dialogs become active to assure follicle development.These findings shed new insights on the transcriptome dynamics and cell dialogs facilitating the development and maturation of oocytes and follicles.

An osteosarcoma-on-a-chip model for studying osteosarcoma matrix-cell interactions and drug responses

Marrow niches in osteosarcoma(OS)are a specialized microenvironment that is essential for the maintenance and regulation of OS cells.However,existing animal xenograft models are plagued by variability,complexity,and high cost.Herein,we used a decellularized osteosarcoma extracellular matrix(dOsEM)loaded with extracellular vesicles from human bone marrow-derived stem cells(hBMSC-EVs)and OS cells as a bioink to construct a micro-osteosarcoma(micro-OS)through 3D printing.The micro-OS was further combined with a microfluidic system to develop into an OS-on-a-chip(OOC)with a built-in recirculating perfusion system.The OOC system successfully integrated bone marrow niches,cell‒cell and cell-matrix crosstalk,and circulation,allowing a more accurate representation of OS characteristics in vivo.Moreover,the OOC system may serve as a valuable research platform for studying OS biological mechanisms compared with traditional xenograft models and is expected to enable precise and rapid evaluation and consequently more effective and comprehensive treatments for OS.

Comprehensive transcriptional atlas of human adenomyosis deciphered by the integration of single-cell RNA-sequencing and spatial transcriptomics

Adenomyosis is a poorly understood gynecological disorder lacking effective treatments.Controversy persists regarding“invagination”and“metaplasia”theories.The endometrial-myometrial junction(EMJ)connects the endometrium and myometrium and is important for diagnosing and classifying adenomyosis,but its in-depth study is just beginning.Using single-cell RNA sequencing and spatial profiling,we mapped transcriptional alterations across eutopic endometrium,lesions,and EMJ.Within lesions,we identified unique epithelial(LGR5+)and invasive stromal(PKIB+)subpopulations,along with WFDC1+progenitor cells,supporting a complex interplay between“invagination”and“metaplasia”theories of pathogenesis.Further,we observed endothelial cell heterogeneity and abnormal angiogenic signaling involving vascular endothelial growth factor and angiopoietin pathways.Cell-cell communication differed markedly between ectopic and eutopic endometrium,with aberrant signaling in lesions involving pleiotrophin,TWEAK,and WNT cascades.This study reveals unique stem cell-like and invasive cell subpopulations within adenomyosis lesions identified,dysfunctional signaling,and EMJ abnormalities critical to developing precise diagnostic and therapeutic strategies.

The Functions of MicroRNAs and Long Non-coding RNAs in Embryonic and Induced Pluripotent Stem Cells

Embryonic stern cells （ESCs） and induced pluripotent stem cells （iPSCs） hold immense promise for regenerative medicine due to their abilities to self-renew and to differentiate into all cell types. This unique property is controlled by a complex interplay between transcriptional factors and epigenefic regulators. Recent research indicates that the epigenetic role of non-coding RNAs （ncRNAs） is an integral component of this regulatory network. This report will summarize findings that focus on two classes of regulatory ncRNAs, microRNAs （miRNAs） and long ncRNAs （lncRNAs）, in the induction, maintenance and directed differentiation of ESCs and iPSCs. Manipulating these two important types of ncRNAs would be crucial to unlock the therapeutic and research potential of pluripotent stem cells.

Esrrb plays important roles in maintaining self-renewal of trophoblast stem cells (TSCs) and reprogramming somatic cells to induced TSCs

Trophoblast stem cells (TSCs), which can be derived from the trophoectoderm of a blastocyst, have the ability to sustain self-renewal and differentiate into various placental trophoblast cell types. Meanwhile, essential insights into the molecular mechanisms controlling the placental development can be gained by using TSCs as the cell model. Esrrb is a transcription factor that has been shown to play pivotal roles in both embryonic stem cell (ESC) and TSC, but the precise mechanism whereby Esrrb regulates TSC-specific transcriptome during differentiation and reprogramming is still largely unknown. In the present study, we elucidate the function of Esrrb in self-renewal and differentiation of TSCs, as well as during the induced TSC (iTSC) reprogramming. We demonstrate that the precise level of Esrrb is critical for stem state maintenance and further trophoblast differentiation of TSCs, as ectopically expressed Esrrb can partially block the rapid differentiation of TSCs in the absence of fibroblast growth factor 4. However, Esrrb depletion results in downregulation of certain key TSC-specific transcription factors, consequently causing a rapid differentiation of TSCs and these Esrrb-deficient TSCs lose the ability of hemorrhagic lesion formation in vivo. This function of Esrrb is exerted by directly binding and activating a core set of TSC-specific target genes including Cdx2, Eomes, Sox2, Fgfr4, and Bmp4. Furthermore, we show that Esrrb overexpression can facilitate the MEF-to-iTSC conversion. Moreover, Esrrb can substitute for Eomes to generate GEsTM-iTSCs. Thus, our findings provide a better understanding of the molecular mechanism of Esrrb in maintaining TSC self-renewal and during iTSC reprogramming.

METTL5 stabilizes c-Myc by facilitating USP5 translation to reprogram glucose metabolism and promote hepatocellular carcinoma progression

Background:Hepatocellular carcinoma(HCC)is one of the most prevalent cancers in the world,with a high likelihood of metastasis and a dismal prognosis.The reprogramming of glucosemetabolism is critical in the development ofHCC.TheWarburg effect has recently been confirmed to occur in a variety of cancers,including HCC.However,little is known about the molecular biological mechanisms underlying the Warburg effect in HCC cells.In this study,we sought to better understand how methyltransferase 5,N6-adenosine(METTL5)controls the development of HCC and theWarburg effect.Methods:In the current study,quantitative real-time polymerase chain reaction and Western blotting were used to detect the expression of METTL5 in HCC tissues and cell lines.Several different cell models and animal models were established to determine the role of METTL5 in glucose metabolism reprogramming and the underlying molecularmechanism of HCC.Glutathione-S-transferase pulldown,coimmunoprecipitation,RNA sequencing,non-targeted metabolomics,polysome profiling,and luciferase reporter assays were performed to investigate the molecular mechanisms of METTL5 in HCC cells.Results:We discovered that METTL5 drove glucose metabolic reprogramming to promote the proliferation and metastasis of HCC.Mechanistically,upregulation of METTL5 promoted c-Myc stability and thus activated its downstream glycolytic genes lactate dehydrogenase A(LDHA),enolase 1(ENO1),triosephosphate isomerase 1(TPI1),solute carrier family 2 member 1(SLC2A1),and pyruvate kinase M2(PKM2).The c-Box and ubiquitin binding domain(UBA)regions of ubiquitin specific peptidase 5(USP5)binded to c-Myc protein and inhibited K48-linked polyubiquitination of c-Myc.Further study revealed that METTL5 controled the USP5 translation process,which in turn regulated the ubiquitination of c-Myc.Furthermore,we identified cAMP responsive element binding protein 1(CREB1)/P300 as a critical transcriptional regulator ofMETTL5 that promoted the transcription of METTL5 in HCC.In patient-derived tumor xenograft(PDX)models,adenovirus-mediated knockout of METTL5 had a good antitumor effect and prolonged the survival of PDX-bearing mice.Conclusions:These findings point to a novel mechanism by which CREB1/P300-METTL5-USP5-c-Myc controls abnormal glucose metabolism and promotes tumor growth,suggesting that METTL5 is a potential therapeutic target and prognostic biomarker for HCC.

Lessons from expanded potential of embryonic stem cells:Moving toward totipotency

Embryonic stem cells possess fascinating capacity of self-renewal and developmental potential,leading to significant progress in understanding the molecular basis of pluripotency,disease modeling,and reprogramming technology.Recently,2-cell-like embryonic stem cells(ESCs)and expanded potential stem cells or extended pluripotent stem cells(EPSCs)generated from early-cleavage embryos display some features of totipotent embryos.These cell lines provide valuable in vitro models to study underlying principles of totipotency,cell plasticity,and lineage segregation.In this review,we summarize the current progress in this filed and highlight the application potentials of these cells in the future.

Single-Cell RNA Expression Profiling of ACE2 and AXL in the Human Maternal-Fetal Interface

2019 novel coronavirus disease has resulted in thousands of critically ill patients in China,which is a serious threat to people’s life and health.Severe acute respiratory syndrome-coronavirus 2(SARS-CoV-2)was reported to share the same receptor,angiotensin-converting enzyme 2(ACE2),with SARS-CoV.Here,based on the public single-cell RNA-sequencing database,we analyzed the mRNA expression profile of putative receptor ACE2 and AXL receptor tyrosine kinase(AXL)in the early maternal-fetal interface.The result indicates that the ACE2 has very low expression in the different cell types of early maternal-fetal interface,except slightly high in decidual perivascular cells cluster 1(PV1).Interestingly,we found that the Zika virus(ZIKV)receptor AXL expression is concentrated in perivascular cells and stromal cells,indicating that there are relatively more AXL-expressing cells in the early maternal-fetal interface.This study provides a possible infection route and mechanism for the SARS-CoV-2-or ZIKV-infected mother-to-fetus transmission disease,which could be informative for future therapeutic strategy development.

Additively manufactured biodegradable porous magnesium implants for elimination of implant-related infections:An in vitro and in vivo study

Magnesium(Mg)alloys that have both antibacterial and osteogenic properties are suitable candidates for orthopedic implants.However,the fabrication of ideal Mg implants suitable for bone repair remains challenging because it requires implants with interconnected pore structures and personalized geometric shapes.In this study,we fabricated a porous 3D-printed Mg-Nd-Zn-Zr(denoted as JDBM)implant with suitable mechanical properties using selective laser melting technology.The 3D-printed JDBM implant exhibited cytocompatibility in MC3T3-E1 and RAW267.4 cells and excellent osteoinductivity in vitro.Furthermore,the implant demonstrated excellent antibacterial ratios of 90.0% and 92.1% for methicillin-resistant S.aureus(MRSA)and Escherichia coli,respectively.The 3D-printed JDBM implant prevented MRSA-induced implant-related infection in a rabbit model and showed good in vivo biocompatibility based on the results of histological evaluation,blood tests,and Mg2+deposition detection.In addition,enhanced inflammatory response and TNF-α secretion were observed at the bone-implant interface of the 3D-printed JDBM implants during the early implantation stage.The high Mg^(2+)environment produced by the degradation of 3D-printed JDBM implants could promote M1 phenotype of macrophages(Tnf,iNOS,Ccl3,Ccl4,Ccl5,Cxcl10,and Cxcl2),and enhance the phagocytic ability of macrophages.The enhanced immunoregulatory effect generated by relatively fast Mg^(2+)release and implant degradation during the early implantation stage is a potential antibacterial mechanism of Mg-based implant.Our findings indicate that 3D-printed porous JDBM implants,having both antibacterial property and osteoinductivity,hold potential for future orthopedic applications.

3D Printing Bioink Preparation and Application in Cartilage Tissue Reconstruction in Vitro

Three-dimensional(3D)bioprinting technology has great potential for application in the treatment of cartilage defects.However,the preparation of biocompatible and stable bioinks is still a major challenge.In this study,decellularized extracellular matrix(dECM)of soft tissue was used as the basic material to prepare the bioink.Our results showed that this novel dECM-derived bioink had good printing performance and comprised a large number of fine nanofibers.Biological characterization revealed that the bioink was compatible with the growth of chondrocytes and that the nanofibrous structure greatly promoted cell proliferation.Histological and immunohistochemical analyses showed that the in vitro printed cartilage displayed the presence of characteristic cartilage lacunae.Thus,a new preparation method for dECM-derived bioink with potential application in generation of cartilage was developed in this study.