Breast cancer is the most common cancer in women and one of the deadliest cancers worldwide.According to the distribution of tumor tissue,breast cancer can be divided into invasive and non-invasive forms.The cancer cells in invasive breast cancer pass through the breast and through the immune system or systemic circulation to different parts of the body,forming metastatic breast cancer.Drug resistance and distant metastasis are the main causes of death from breast cancer.Research on breast cancer has attracted extensive attention from researchers.In vitro construction of tumor models by tissue engineering methods is a common tool for studying cancer mechanisms and anticancer drug screening.The tumor microenvironment consists of cancer cells and various types of stromal cells,including fibroblasts,endothelial cells,mesenchymal cells,and immune cells embedded in the extracellular matrix.The extracellular matrix contains fibrin proteins(such as types Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅵ,and Ⅹcollagen and elastin)and glycoproteins(such as proteoglycan,laminin,and fibronectin),which are involved in cell signaling and binding of growth factors.The current traditional two-dimensional(2D)tumor models are limited by the growth environment and often cannot accurately reproduce the heterogeneity and complexity of tumor tissues in vivo.Therefore,in recent years,research on three-dimensional(3D)tumor models has gradually increased,especially 3D bioprinting models with high precision and repeatability.Compared with a 2D model,the 3D environment can better simulate the complex extracellular matrix components and structures in the tumor microenvironment.Three-dimensional models are often used as a bridge between 2D cellular level experiments and animal experiments.Acellular matrix,gelatin,sodium alginate,and other natural materials are widely used in the construction of tumor models because of their excellent biocompatibility and non-immune rejection.Here,we review various natural scaffold materials and construction methods involved in 3D tissue-engineered tumor models,as a reference for research in the field of breast cancer.

Cardiac-resident macrophages (CRMs) play important roles in homeostasis, cardiac function, and remodeling. Although CRMs play critical roles in cardiac regeneration of neonatal mice, their roles are yet to be fully elucidated. Therefore, this study aimed to investigate the dynamic changes of CRMs during cardiac ontogeny and analyze the phenotypic and functional properties of CRMs in the promotion of cardiac regeneration. During mouse cardiac ontogeny, four CRM subsets exist successively: CX₃CR1⁺CCR2^-Ly6C^-MHCII^- (MP1), CX₃CR1^lowCCR2^lowLy6C^-MHCII^- (MP2), CX₃CR1^-CCR2⁺Ly6C⁺MHCII^- (MP3), and CX₃CR1⁺CCR2^-Ly6C^-MHCII⁺ (MP4). MP1 cluster has different derivations (yolk sac, fetal liver, and bone marrow) and multiple functions population. Embryonic and neonatal-derived-MP1 directly promoted cardiomyocyte proliferation through Jagged-1-Notch1 axis and significantly ameliorated cardiac injury following myocardial infarction. MP2/3 subsets could survive throughout adulthood. MP4, the main population in adult mouse hearts, contributed to inflammation. During ontogeny, MP1 can convert into MP4 triggered by changes in the cellular redox state. These findings delineate the evolutionary dynamics of CRMs under physiological conditions and found direct evidence that embryonic and neonatal-derived CRMs regulate cardiomyocyte proliferation. Our findings also shed light on cardiac repair following injury.

Objective To analyze the clinical features and risk factors of delayed intracranial hemorrhage (DICH) after ventriculoperitoneal shunt (VPS) in patients with communicating hydrocephalus.Methods One hundred and seventy-six patients with ventriculoperitoneal shunt due to communicating hydrocephalus secondary to craniocerebral trauma,hypertensive intracerebral hemorrhage,brain tumor or intracranial aneurysm rupture hemorrhage,admitted to our hospital from January 2012 to August 2018,were selected in our study;these patients were divided into DICH group and non-DICH group according to whether or not DICH occurred.The clinical features,including incidence,time and location of DICH,were analyzed.The differences of age,gender,length of stay,concomitant diseases,previous operation history,incidences of subdural effusion and puncture canal edema after ventriculoperitoneal shunt,and history of down-regulating shunt valve within 2 weeks between the two groups were compared by univariate analysis.The independent risk factors for DICH were further assessed using multivariable Logistic regression.Results Among 176 patients,23 (13.07％) had DICH;2-11 d after surgery,DICH appeared,manifesting as subdural,ventriculoventricular end canal and/or hemorrhage in one or more areas of the ventricle.There were significant differences in incidence of subdural effusion and history of down-regulating shunt valve within 2 weeks between the two groups (P＜0.05).Multivariate Logistic regression analysis showed that subdural effusion after surgery and down-regulation of shunt valve pressure within 2 weeks after ventriculoperitoneal shunt were independent risk factors for DICH (OR=4.516,95％CI:1.555-13.110,P=0.006;OR=5.352,95％CI:1.987-14.414,P=0.001).Conclusion High incidence of DICH mighty be noted within two weeks of ventriculoperitoneal shunt;subdural effusion and pressure reduction of shunt valve within 2 weeks are independent risk factors for DICH,which needs close monitoring and clinical intervention.

Objective To explore the effect of a new organ preservation solution with HOE642 on the apoptosis of the donor lung from a modified lung transplantation model of rabbits.Methods 24 male rabbits were divided into two groups [low potassium dextran (LPD) group and HOE group],established rabbit models for next 2-h reperfusion using LPD solution or new organ preservation solution.Detected the levles of apoptosis index and caspase-3,the expression of Fas/Fas-L and Bcl-2/Bax.Results Compared with LPD group,HOE group revealed significant lower level of apoptosis index and caspase-3 (P＜0.05),lower expression of Fas/Fas-L and Bax,and higher expression of Bcl-2 (P＜0.05).Conclusion The potential donor lung protective mechanism offered by the new organ preservation solution with HOE642 might be the inhibition of apoptosis via both intrinsic and extrinsic pathways.

Objective To systematically evaluate the biomechanical recovery of drilled holes in the femur in SD rats.Methods Eighteen female SD rats were randomized into 3 even groups (n =6).Models of 2-mm drilled holes in bilateral femurs were established in groups A and B with 2 holes on each side while no drilling was performed in group C.Samples were harvested in group A at postoperative 4 weeks,in group B at postoperative 8 weeks while at both 4 and 8 weeks in group C.The samples were evaluated in terms of linear elasticity (compression test),viscoelasticity (relaxation and creep tests) and durability (fatigue failure test).Micro-CT scan was performed to measure the bone volume fraction (BV/TV) and bone mineral density (BMD) of new bone.Sirus red staining was performed to measure regeneration of type Ⅰ collagen of new bone.Results The elasticity modulus,maximum load,compression strength and conditional yield limit in groups A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).At 7,200 s,the relaxation (14.56 ±0.69 MPa) and creep variation (11.37％ ± 0.70％) in group A were significantly higher than those in group B (11.06 0.63 MPa and 8.98％ ± 0.40％) which were also significantly higher than those in group C (6.99 ±0.56 MPa and 5.10％ ±0.23％) (P ＜ 0.05).At the constant amplitude loads from 20 N to 200 N,from 20 N to 300 N and from 20 N to 400 N,the recycling numbers in group A (6,044.3 ±879.7,4,093.3 ±628.5 and 1,919.3 ±847.5) were significantly lower than those in group B (10,192.3 ± 1,109.1,6,750.6 ± 818.0 and 3,376.6 ± 671.3) which were also significantly lower than those in group C (28,068.3 ±2,702.6,11,788.3 ± 1,141.6 and 5,296.3 ± 735.0) (P ＜ 0.05).By micro-CT scan,the BVT and BMD in group A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).The sirus red staining showed the type Ⅰ collagen in the bone defect area was completely regenerated in group B.Conclusion Systematic biomechanical measurements may actually detect the characteristics of biomechanical recovery of bone holes in SD rats,enriching the basic research on the bone damage repairing progress.

Objective To investigate the effect of prevascularized tissue-engineered bone graft on regeneration of femoral bone defects in rats.Methods Models of femoral bone defect were created at the bilateral hind limbs of 20 healthy female 10 week-old rats which were divided into 2 even groups randomly (n =10).In group A,conventional tissue-engineered bone grafts were transplanted into the femoral bone defects;in group B,tissue-engineered bone grafts and vascular bundles were implanted into the femoral defects.At 1,4 and 8 weeks after operation,3 rats were sacrificed each time in each group to harvest samples.The remaining one in each group served as a spare animal.Regeneration of bone defects and degradation of scaffolds were assessed by radiologic modality and hematein eosin staining.Results At week 1,the new bone ratio (BV/TV) was 5.47％ ± 1.90％ in group A and 8.49％ ± 1.26％ in group B,showing no significant difference (P ＞ 0.05);at weeks 4 & 8,the BV/TV were 17.54％ ±2.04％ and 39.73％ ± 4.01％ in group A,significantly lower than those in group B (25.32％ ± 2.15％ and 53.22％ ± 2.94％) (P ＜ 0.05).At weeks 1 & 4,the scaffold degradation ratios (RSV/SV) were 97.33％ ± 2.52％ and 80.60％ ±4.00％,showing no significant differences from those in group B (95.67％ ±3.51％ and 75.22％ ±6.20％) (P ＞ 0.05).At week 8,the scaffold degradation ratio in group A (65.46％ ±4.51％) was significantly higher than that in group B (50.19％ ±4.91％) (P ＜ 0.05).At week 8,hematein eosin staining showed better integration of scaffolds with the femur,faster degradation of the interior scaffolds and greater osteogenetic activity in group B.Conclusion Prevascularization of tissue-engineered bone graft may increase new bone volume and scaffold degradation rate,promoting repair of femoral bone defects in rats.

Objective To understand the knowledge,attitude and behavior on health hazards of haze and secondhand smoke exposure among middle school students in Beijing,and provide us with guidance to carry out effective health education for middle school students.Methods A total of 1 294 students were selected randomly using stratified cluster sampling method;1 085 valid questionnaires were recovered.Among them,739 were junior high school students and 346 were senior high school students.The questionnaire included questions on middle school students' knowledge on haze and secondhand smoke exposure,their attitudes towards the judgement of severity of haze and secondhand smoke exposure and their utilization of protective measures when they are exposed to haze or secondhand smoke.Pearson's chi-squared test was performed to assess differences in knowledge,attitude and behavior between junior middle school students and senior high school students,boys and girls.Results Middle-school students' awareness rate on "the haze and exposure to secondhand smoke may cause respiratory disease" was the highest,which was 93.55％ and 95.76％ respectively.The awareness rate of the fact that haze,secondhand smoke exposure can cause cardiovascular disease was 38.99％ and 55.85％ respectively;while the rate of their awareness on the haze and exposure to secondhand smoke can lead to cancer was the lowest,which was 54.10％ and 69.95％ respectively.The differences was significant in the awareness rate of the fact that respiratory disease,cardio-cerebrovascular disease and cancer can be caused by the haze (x2=732.539,P＜0.05),likewise the differences were significant in the awareness rate of the above three kinds of diseases can be caused by secondhand smoke exposure (x2=460.291,P＜0.05).In the comparison between the severity of haze and smoking hazards,35.94％ of students believe that haze hazards is heavier than tobacco;48.02％ of the students think that the dangers of smoking is greater than haze;16.04％ of the students cannot determine the extent of damage of the haze and smoke.The proportion of students who think smoking was more harmful than haze was higher in junior high school group than in senior high school group.The two groups had a significant difference in the understanding of the severity comparison between haze and smoking (x2=13.014,P＜0.05).The differences between boys and girls in the view of the severity comparison between haze and smoking are also statistically significant,more boys believed smoking was more harmful than haze (x2=9.650,P＜0.05).In the aspect of protection from haze and secondhand smoke exposure,86.36％ of the students would like to protect themselves from haze,while 55.94％ of the students would take measures to prevent the secondhand smoke exposure initiatively,the junior high school students performed better than the senior high school students in this two aspects(x2=17.125,P＜0.05;x2=45.785,P＜0.05).Conclusion While middle school students have a certain understanding of the impact of haze and secondhand smoke exposure on health hazards,their understanding is limited.They have not paid enough attention to the harm of secondhand smoke exposure and their awareness of active refusal to secondhand smoke exposure needs to be improved.Schools should strengthen the health education for students and educate them not only to stay away from haze but also should be far away from secondhand smoke exposure.

Objective To investigate the expression and role of β-catenin in small-for-size liver grafts during early stage of liver regeneration after liver transplantation in rats.Method The livers of male Sprague-Dawley rats were reduced to 30％ or 50％ of their original sizes and transplanted.The experiment was divided into 3 groups:small-for-size graft group (SSG),half-size graft group (HSG) and sham-operated group.Liver samples were harvested at various time points after transplantation (n =6 per time point) for Western blotting and immunohistochemistry.Six rats in each group were sacrificed at 3rd day after liver transplantation for estimating liver regeneration rate.Result Liver regeneration rate in SSG group was lower than that in HSG group.The expression of β-catenin was down-regulated in liver graft of both groups after being stored in cold Ringer solution for 2 h.The expression of β-catenin was significant up-regulated in HSG group from 5 min to 12 h after operation,while the down-regulated expression of β-catenin was persisted in SSG group at 5 min after operation,and mildly increased expression of β-catenin occurred at 2 h and 6 h,which was significantly lower than that in HSG group at the corresponding time points.The expression of active-β-catenin was low in each group before transplantation.Significant expression of active-β-catenin was found at 5 min in HSG group and persisted until 12 h after operation,mildly increased expression of active-β-catenin in SSG group was only found at 2 h,which was lower than that in HSG group at the same time points.Immunohistochemical staining revealed that β-catenin was mainly expressed on the hepatocyte membrane and in cytoplasm in the sham-operative group,many hepatocytes exhibited nuclear localization of β-catenin in HSG group from 5 min to 24 h,while only some hepatocytes exhibited nuclear localization of β-catenin in SSG group.The expression of Cyclin D1 in SSG group was significantly lower than that in HSG group,which was similar to the expression of C-Myc.Conclusion Attenuated activation of Wnt/β-catenin signaling and down-regulated expression of target genes during early regeneration of small-for-size liver grafts may be involved in the inhibition of liver regeneration of small for size liver grafts.

Poly (N-isopropylacrylamide) (PNIPAAm), a temperature-responsive polymer, can be potentially applied to replace enzymes or cell scrapers to recover attached cells. Taking full advantage of this unique function of PNIPAAm, cells can be protected from enzymatic hydrolysis and mechanical treatment, thereby to provide ideal seed cells with high quality for biomedical fields. In this review we describe the method to facilitate cell effective adhesion and rapid detachment on thermoresponsive two dimensional surfaces, including selecting special substrate, introducing hydrophilic group, adjusting reactant ratio, controlling polymer thickness/density, providing appropriate external force, so as to effectively improve adherent cell adaptability to thermoresponsive surfaces, depress the risk of bacterial contamination and reduce the effect of low-temperature treatment on the cells. The three dimensional cell culture systems involved in temperature-sensitive microcarriers, scaffolds and gels were briefly discussed. The application based on the platforms for cell culture was also presented.
Acrylic Resins ; Cell Adhesion ; Cell Culture Techniques ; Temperature

To study the effect of sphingosine-1-phosphate (S1P) on the cardiomyogenic differentiation of human umbilical cord mesenchymal stem cells (UC-MSCs) and human adipose-derived mesenchymal stem cells (AD-MSCs), we seeded the cells in the culture plates and used cardiomyocyte culture medium (CMCM) combining with different concentration of S1P to induce UC-MSCs and AD-MSCs in vitro for 7, 14 and 28 days. Cardiomyogenic differentiations were identified through immunofluorescence staining, and the results were observed with fluorescence microscopy and confocal microscopy. The effects of S1P and CMCM on cell activity were evaluated by the methyl thiazolyl tetrazolium assay. The functional characteristic similar to cardiomyocytes was evaluated through detecting calcium transient. Our results showed that cardiomyogenic differentiation of UC-MSCs or AD-MSCs were enhanced with S1P concentration increasing, but cell activities declined. Results showed that the suitable differentiation time was 14 days, and the optimal concentration of S1P was 0.5 micromol/L. When working together with CMCM, S1P could promote the differentiation of UC-MSCs or AD-MSCs into functional cardiomyocytes, giving rise to specific electrophysiological properties (the calcium transient). Taken together, our results suggested that S1P could promote the differentiation of UC-MSCs or AD-MSCs into functional cardiomyocytes when being cultured in CMCM.
Adipose Tissue ; cytology ; metabolism ; Cell Differentiation ; drug effects ; Cells, Cultured ; Culture Media ; Humans ; Lysophospholipids ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Myocytes, Cardiac ; cytology ; Sphingosine ; analogs & derivatives ; pharmacology ; Umbilical Cord ; cytology