Three-dimensional printing and decellularized-extracellular-matrix based methods for advances in artificial blood vessel fabrication: A review

Blood vessels are the tubes through which blood flows and are divided into three types: millimeter-scale arteries, veins, and capillaries as well as micrometer-scale capillaries. Arteries and veins are the conduits that carry blood, while capillaries are where blood exchanges substances with tissues. Blood vessels are mainly composed of collagen fibers, elastic fibers, glycosaminoglycans and other macromolecular substances. There are about 19 feet of blood vessels per square inch of skin in the human body, which shows how important blood vessels are to the human body. Because cardiovascular disease and vascular trauma are common in the population, a great number of researches have been carried out in recent years by simulating the structures and functions of the person's own blood vessels to create different levels of tissue-engineered blood vessels that can replace damaged blood vessels in the human body. However, due to the lack of effective oxygen and nutrient delivery mechanisms, these tissue-engineered vessels have not been used clinically. Therefore, in order to achieve better vascularization of engineered vascular tissue, researchers have widely explored the design methods of vascular systems of various sizes. In the near future, these carefully designed and constructed tissue engineered blood vessels are expected to have practical clinical applications. Exploring how to form multi-scale vascular networks and improve their compatibility with the host vascular system will be very beneficial in achieving this goal. Among them, 3D printing has the advantages of high precision and design flexibility, and the decellularized matrix retains active ingredients such as collagen, elastin, and glycosaminoglycan, while removing the immunogenic substance DNA. In this review, technologies and advances in 3D printing and decellularization-based artificial blood vessel manufacturing methods are systematically discussed. Recent examples of vascular systems designed are introduced in details, the main problems and challenges in the clinical application of vascular tissue restriction are discussed and pointed out, and the future development trends in the field of tissue engineered blood vessels are also prospected.

[Prevention and treatment of endometrial cancer]

Endometrial cancer is rising in incidence, especially in young women. This rise in incidence has implications for both primary prevention and screening in high-risk population. In the past several years, our understanding of the integration of clinically related genomic and pathologic data optimized the management of endometrial cancer. The updated 2023 FIGO staging includes the histological and molecular classification to better reflect the improved understanding of the heterogenous nature of endometrial carcinoma. Standard primary treatment is quite essential, however, selection of patients for adjuvant radiation or chemotherapy remains in controversy. Molecular characterization of endometrial cancer is becoming critical in directing treatment for advanced and recurrent disease, and the addition of immunotherapy to frontline chemotherapy is becoming the standard of care. More attention should be given to increase awareness of survivorship issues and improve patient quality-of-life.

Electromagnetic field-mediated chitosan/gelatin/nano-hydroxyapatite and bone-derived scaffolds regulate the osteoblastic and chondrogenic phenotypes of adipose-derived stem cells to construct osteochondral tissue engineering niche in vitro

It is critical to explore the effects of electromagnetic field (EMF) on the construction of functional osteochondral tissue, which has shown certain clinical significance for the treatment of osteochondral injury. At present, there are few studies on the effect of the direction of EMF on cells. This study aimed to investigate the effects of EMF coupling on different parameters to control adipose-derived stem cells (ADSCs) proliferation and specific chondrogenic and osteogenic differentiation at 2D level and 3D level. The proliferation and differentiation of EMF-induced ADSCs are jointly regulated by EMF and space structure. In this study, Cs7/Gel3/nHAP scaffolds were prepared with good degradation rate (86.75 ± 4.96 %) and absorb water (1100 %), and the pore size was 195.63 ± 54.72 μm. The bone-derived scaffold with a pore size of 267.17 ± 129.18 μm was obtained and its main component was hydroxyapatite. Cs7/Gel3/nHAP scaffolds and bone-derived scaffolds are suitable as 3D level materials. The optimal EMF intensity was 2 mT for chondrogenic differentiation and proliferation and 1 mT for osteogenic differentiation and proliferation. It is noteworthy that EMF has a negative correlation with ADSCs proliferation in the vertical direction at 2D level, while it has a positive correlation with ADSCs proliferation at 3D level. EMF mediated 3D osteochondral scaffold provide good strategy for osteochondral tissue engineering construction.

Optimization of Flavonoid Extraction from Eucommia ulmoides pollen using Respond Surface Methodology and its biological activities

Flavonoids, known for their abundance in Eucommia ulmoides pollen, possess diverse biological functions, including antioxidants, antibacterial agents, and anti-tumor properties. This study aims to establish effective parameters for flavonoid extraction from Eucommia ulmoides pollen using a microwave-assisted method, characterize the flavonoid composition of the extracted material, and explore its biological activities. Building upon the initial results from single-factor experiments, response surface methodology was employed to optimize the extraction parameters. The inhibitory effect of human breast cancer cells (MCF-7) was evaluated by CCK assay and Live/dead staining. Simultaneously, the extract's scavenging ability against DPPH free radicals and its antibacterial properties against Escherichia coli and Staphylococcus aureus were investigated. The results demonstrated that the flavonoid yield reached 3.28 g per 100 g of pollen, closely aligning with the predicted value. The IC50 for flavonoid-mediated DPPH radical scavenging was 0.04 mg/mL. The extract exhibited a robust inhibitory effect on both Escherichia coli and Staphylococcus aureus. Concurrently, the extract displayed a significant inhibitory effect on the growth and proliferation of MCF-7 cells in a dose-dependent and time-dependent manner. In addition, six kinds of flavonoids have been identified by UPLC-TOF-MS/MS technology, providing further support to the study on the anti-oxidation and anti-tumor mechanism of Eucommia ulmoides pollen extracts.

Caffeic acid-grafted chitosan/sodium alginate/nanoclay-based multifunctional 3D-printed hybrid scaffolds for local drug release therapy after breast cancer surgery

Breast cancer is one of the most common malignant tumors in women all over the world. Mastectomy is the most effective treatment, but there are serious problems such as high tumor recurrence rate and side effects of chemotherapy. Therefore, there is an urgent need for a therapeutic strategy that can effectively promote postoperative wound healing and inhibit local tumor recurrence. In this study, a 3D printing scaffold based on carbon dots-curcumin nano-drug release (CCNPs) was developed as a local drug delivery platform (named CCNACA using CCNPs, Sodium alginate, Nanoclay and Caffeic Acid grafted Chitosan as raw materials), which has the ability to visualize drug release. The 14-day drug release test in vitro showed that the tumor inhibition rate of CCNACA scaffolds on breast cancer cells (MCF-7) was 73.77 ± 1.68 %. And the CCNACA scaffolds had good long-term antibacterial (Escherichia coli and Staphylococcus aureus) activity. Animal experiments have shown that implanting CCNACA scaffolds into surgical defects can inhibit postoperative residual cancer cells, reduce inflammation, promote angiogenesis, and repair tissue defects caused by surgery. In summary, the local drug delivery system of this manuscript has great potential in wound healing and prevention of tumor recurrence after breast cancer surgery.

Choline induced cardiac dysfunction by inhibiting the production of endogenous hydrogen sulfide in spontaneously hypertensive rats

To investigate the exact effects of dietary choline on hypertensive heart disease (HHD) and explore the potential mechanisms, male spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) were randomly divided into five groups as follows: WKY group, WKY + Choline group, SHR group, SHR + Choline group, and SHR + Choline + NaHS group. In choline treatment groups, rats were fed with 1.3% (w/v) choline in the drinking water for 3 months. The rats in the SHR + Choline + NaHS group were intraperitoneally injected with NaHS (100 micromol/kg/day, a hydrogen sulfide (H2S) donor) for 3 months. After 3 months, left ventricular ejection fraction (LVEF) and fractional shortening (LVFS), the indicators of cardiac function measured by echocardiography, were increased significantly in SHR as compared to WKY, although there was no significant difference in collagen volumes and Bax/Bcl-2 ratio between the two groups, indicating the early stage of cardiac hypertrophy. There was a significant decrease in LVEF and LVFS and an increase in collagen volumes and Bax/Bcl-2 ratio in SHR fed with choline, meanwhile, plasma H2S levels were significantly decreased significantly in SHR fed with choline accompanying by the decrease of cystathionine-gamma-lyase (CSE) activity. Three months of NaHS significantly increased plasma H2S levels, ameliorated cardiac dysfunction and inhibited cardiac fibrosis and apoptosis in SHR fed with choline. In conclusion, choline aggravated cardiac dysfunction in HHD through inhibiting the production of endogenous H2S, which was reversed by supplementation of exogenous H2S donor.

Real world data on outcomes of anti-CD38 antibody treated, including triple class refractory, patients with multiple myeloma: a multi-institutional report from the Canadian Myeloma Research Group (CMRG) Database

Multiple myeloma (MM) remains incurable despite the availability of novel agents. This multi-center retrospective cohort study used the Canadian Myeloma Research Group Database to describe real-world outcomes of patients withanti-CD38 monoclonal antibody (mAb) refractory MM subsequently treated with standard of care (SoC) regimens. Patients with triple class refractory (TCR) disease (refractory to a proteasome inhibitor, immunomodulatory drug, and anti-CD38 mAb) were examined as a distinct cohort. Overall, 663 patients had disease progression on anti-CD38 mAb therapy, 466 received further treatment (346 with SoC regimens were included, 120 with investigational agents on clinical trial and were excluded). The median age at initiation of subsequent SoC therapy of 67.9 (range 39.6-89.6) years with a median of 3 prior lines (range 1-9). The median PFS and OS from the start of subsequent therapy was 4.6 (95% CI 4.1-5.6) months and 13.3 (95% CI 10.6-16.6) months, respectively. The median PFS and OS of patients with TCR disease (n = 199) was 4.4 (95% CI 3.6-5.3) months and 10.5 (95% CI 8.5-13.8) months. Our results reinforce that real-world patients with relapsed MM, particularly those with TCR disease, have dismal outcomes. There remains an urgent unmet need for the development of and access to effective therapeutics for these patients.

Investigation on repairing diabetic foot ulcer based on 3D bio-printing Gel/dECM/Qcs composite scaffolds

Diabetic foot ulcers are one of the most serious of the numerous complications of diabetes mellitus, causing great physical trauma and financial stress to patients, and accelerating wound healing in diabetic patients remains one of the major clinical challenges. Exosomes from adipose-derived stem cells can directly and indirectly promote wound healing. However, due to the low retention rate of exosomes in the wound, exosome treatment is difficult to achieve the expected effect. Therefore, it is of great significance to synthesize a composite scaffold that can stably load exosomes and has antibacterial properties. In this study, fresh pig skin was decellularized to obtain decellularized matrix (dECM). Secondly, quaternized chitosan (Qcs) was modified with quaternary ammonium salt to make it soluble in water after quaternization. Finally, Gel-dECM-Qcs (GDQ) bioink was prepared by adding acellular matrix and quaternized chitosan with temperature sensitive gelatin (Gel) as carrier. Tissue engineered composite scaffolds were then prepared by extrusion 3D printing technology. Subsequently, the physicochemical properties, biocompatibility and antimicrobial capacity of the composite scaffolds were determined, and the data showed that the composite scaffolds had good mechanical properties, biocompatibility and antimicrobial capacity, and the maximum stress of the composite scaffolds was 1.16 ± 0.05 MPa, the composite scaffolds were able to proliferate and adhered to the L929 cells, and the kill rates of composite scaffolds against E. coli and S. aureus after incubation for 24 h were 93.24 ± 1.22 % and 97.34 ± 0.23 %, respectively. Overall, the GDQ composite scaffolds have good mechanical properties adapted to skin bending, its good biocompatibility can promote the growth and migration of fibroblasts, reshape injured tissues, accelerate the wound healing, and excellent antimicrobial ability can inhibit the growth of E. coli and S. aureus, reducing the impact of bacterial infections on wounds. Moreover, the composite scaffolds have the potential to be used as exosom-loaded hydrogel dressings, which provides a basis for the subsequent research on the repair of diabetic foot ulcers.

Study of Finite Element Simulation on the Mechano-Bactericidal Mechanism of Hierarchical Nanostructure Arrays

Biomimetic nanostructures with bactericidal performance have become the research focus in constructing sterilization surfaces, but the mechano-bactericidal mechanism is still not fully understood, especially for the hierarchical nanostructure arrays with different heights. Herein, the interaction between Escherichia coli cells and nanostructure arrays was simulated by finite element, and the initial rupture points, i.e., critical action sites, of bacterial cells and the effects of nanostructure geometries on the cell rupture speed were analyzed based on the mechano-response of Escherichia coli cells on flat (identical heights) and hierarchical nanostructure arrays. The critical action sites of bacterial cells on nanostructure arrays are all at the three-phase junction zone of cell-liquid-nanostructure, but they are slightly shifted by the height difference ΔH of nanostructures on hierarchical nanopillar (NP)/nanosheet (NS) arrays, where the NP is higher than the NS. When ΔH < 20 nm, the site nears the NS corners, and when ΔH ≥ 20 nm, the site is consistent with that of the NP/NP array, i.e., the site locates at the three-phase junction zone of cell-liquid-high NP. In addition, except for decreasing the NP diameter, the NS thickness/width, or properly increasing the nanostructure spacing, the cell rupture can be accelerated via increasing the ΔH of nanostructures. ΔH = 40 nm is distinguished as the boundary for the effect of nanostructure ΔH on the cell rupture speed. When ΔH < 40 nm, the cell rupture speed rapidly increases as the ΔH increases; when ΔH ≥ 40 nm, the cell rupture speed reaches the maximum value and remains stable. This study provides a new strategy on how to design high-efficiency bactericidal surfaces.

Reliability of synthetic diffusion-weighted imaging with a high b-value for paediatric abdominal MRI

AIM

To evaluate the reliability of synthetic diffusion-weighted imaging (DWI) using a high b-value in comparison to conventional DWI for paediatric abdominal MRI.

MATERIALS AND METHODS

Paediatric patients (<19 years old) who underwent liver or pancreatobiliary MRI with DWI using 10 b-values (b = 0, 25, 50, 75, 100, 200, 400, 600, 800, 1,500 s/mm2) from March to October 2021 were included in this retrospective study. Using the software, synthetic DWI using b = 1,500 s/mm2 was generated automatically by selecting the b-value required as output. Conventional and synthetic DWI values for b = 1,500 s/mm2 were measured at the liver, spleen, paraspinal muscle, and mass lesions, if present, and apparent diffusion coefficient (ADC) values were calculated using the mono-exponential model. Intraclass correlation coefficients (ICCs) were calculated to assess the reliability of conventional and synthetic DWI and ADC values with b = 1,500 s/mm2.

RESULTS

Thirty paediatric patients (M:F = 22:8, mean 10.8 ± 3.1 years old) were included and four had tumours on abdominal MRI. ICC values were 0.906-0.995 between conventional and synthetic DWI and ADC with b = 1,500 s/mm2 in the liver, spleen and muscle. For mass lesions, ICC values were 0.997-0.999 for both synthetic DWI and ADC images.

CONCLUSIONS

Synthetic DWI and ADC values obtained using a high b-value showed excellent agreement with conventional DWI for the liver, spleen, muscle, and mass in paediatric MRI.

A decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan-based 3D culture system shapes breast cancer lung metastasis

Distal metastasis of breast cancer is a primary cause of death, and the lung is a common metastatic target of breast cancer. However, the role of the lung niche in promoting breast cancer progression is not well understood. Engineered three-dimensional (3D) in vitro models capable of bridging this knowledge gap can be specifically designed to mimic crucial characteristics of the lung niche in a more physiologically relevant context than conventional two-dimensional systems. In this study, two 3D culture systems were developed to mimic the late stage of breast cancer progression at a lung metastatic site. These 3D models were created based on a novel decellularized lung extracellular matrix/chondroitin sulfate/gelatin/chitosan composite material and on a porcine decellularized lung matrix (PDLM), with the former tailored with comparable properties (stiffness, pore size, biochemical composition, and microstructure) to that of the in vivo lung matrix. The different microstructure and stiffness of the two types of scaffolds yielded diverse presentations of MCF-7 cells in terms of cell distribution, cell morphology, and migration. Cells showed better extensions with apparent pseudopods and more homogeneous and reduced migration activity on the composite scaffold compared to those on the PDLM scaffold. Furthermore, alveolar-like structures with superior porous connectivity in the composite scaffold remarkably promoted aggressive cell proliferation and viability. In conclusion, a novel lung matrix-mimetic 3D in vitro breast cancer lung metastasis model was developed to clarify the underlying correlativity between lung ECM and breast cancer cells after lung colonization. A better understanding of the effects of biochemical and biophysical environments of the lung matrix on cell behaviors can help elucidate the potential mechanisms of breast cancer progression and further improve target discovery of therapeutic strategies.

[Mechanism study of platelet derived growth factor receptor alpha on the bidirectional differentiation regulation of glioma-associated oncogene homolog 1-positive mesenchymal stem cells in mice]

Objective: To investigate the role of platelet derived growth factor receptor alpha (PDGFRα) on bidirectional differentiation of glioma-associated oncogene homolog 1-positive mesenchymal stem cells (Gli1+-MSC). Methods: Breeding double reporter transgenic mice ROSAmT/mG/Gli1-Cre^ERt2/PDGFRα^fl (Experimental group) and ROSA^mT/mG/Gli1-Cre^ERt2 (Control group), 20 mice in each of the two groups at four weeks of age were selected, MSC were isolated from the mouse aortic epithelium. After tamoxifen inducement, the two groups of Gli1⁺-MSC were screened by green fluorescent protein (GFP) labeling and flow cytometry sorting. PDGFRα was conditionally knocked out in the experimental group, and the control group Gli1⁺-MSC expressed PDGFRα normally. The two groups of Gli1⁺-MSC were subjected to adipogenic induction and fibrogenic induction, the Western blotting was performed to detect PDGFRα, adipocyte markers [perilipin and CCAAT/enhancer binding protein alpha (C/EBPα)] and fibrogenic markers [alpha smooth muscle actin (α-SMA) and fibroblast-specific protein 1 (FSP-1)] and semi-quantitative analysis was performed. The degree of cellular adipose differentiation after bidirectional induction of Gli1+-MSC in both groups was observed by oil red O staining and analyzed semi-quantitatively. Results: After tamoxifen induction, Gli1⁺-MSC could be accurately isolated from flow cytometry by GFP labeling. Via adipogenic differentiation, the expression of PDGFRα in the experimental group (0.017±0.002) was significantly lower than that in the control group (0.184±0.012) (t=25.48，P=0.002). The protein expressions of perilipin (3.138±0.414) and C/EBPα (3.565±0.289) were significantly higher than those in the control group (2.312±0.218 and 2.179±0.103, respectively) (t=6.21，P=0.025；t=6.69，P=0.022). Thus, the knock-out of PDGFRα enhanced the adipogenic differentiation ability of Gli1⁺-MSC. After fibrogenesis induction, the protein expressions of PDGFRα, α-SMA and FSP-1 in the experimental group (0.030±0.001, 0.932±0.177 and 0.276±0.020, respectively) were significantly lower than those in the control group (0.439±0.006, 1.352±0.170 and 0.835±0.097, respectively) (t=149.40, P<0.001; t=66.38,P<0.001; t=11.41,P<0.08). This suggested that the knock-out of PDGFRα significantly inhibited Gli1⁺-MSC differentiation toward fibroblasts. After bidirectional induction, significantly less adipocyte formation was seen in the control group and more in the experimental group. Quantitative analysis showed that the amount of oil red O staining in the experimental group (0.461±0.042) was significantly higher than that in the control group (0.017±0.007) after bidirectional induction (t=23.20, P<0.01). Conclusions: PDGFRα plays an important role in the regulation of bidirectional differentiation of vascular adventitial Gli1+-MSC.

Functional materials of 3D bioprinting for wound dressings and skin tissue engineering applications: A review

The skin plays an important role in vitamin D synthesis, humoral balance, temperature regulation, and waste excretion. Due to the complexity of the skin, fluids loss, bacterial infection, and other life-threatening secondary complications caused by skin defects often lead to the damage of skin functions. 3D bioprinting technology, as a customized and precise biomanufacturing platform, can manufacture dressings and tissue engineering scaffolds that accurately simulate tissue structure, which is more conducive to wound healing. In recent years, with the development of emerging technologies, an increasing number of 3D-bioprinted wound dressings and skin tissue engineering scaffolds with multiple functions, such as antibacterial, antiinflammatory, antioxidant, hemostatic, and antitumor properties, have significantly improved wound healing and skin treatment. In this article, we review the process of wound healing and summarize the classification of 3D bioprinting technology. Following this, we shift our focus on the functional materials for wound dressing and skin tissue engineering, and also highlight the research progress and development direction of 3D-bioprinted multifunctional wound healing materials.

Construction and properties detection of 3D micro-structure scaffolds base on decellularized sheep kidney before and after crosslinking

Decellularized extracellular matrix is one form of natural material in tissue engineering. The process of dECM retains the tissue microstructure, provides good cell adhesion sites, maintains most of biological signals that promotes the survival and differentiation ability of cells. In this study, sheep kidney was decellularized followed by histochemical staining, elemental analysis and scanning electron microscopy characterizations. The dECM scaffold was prepared with different sequences of freeze drying technology, crosslinking and the water absorption, porosity, mechanical strength with subsequent thermogravimetric analysis, Infrared spectroscopy and biocompatibility tests. Our results indicated that these decellularized treatments of sheep kidney can effectively remove DNA and retain uniform pore size distribution. After crosslinking the scaffold's water absorption decreased from 987.56 ± 40.21% to 934.39 ± 39.61%, the porosity decreased from 89.64 ± 3.2% to 85.09 ± 17.63%, and the compression modulus increased from 304.32 ± 25.43 kPa to 459.53 ± 38.92 kPa, with thermal process the percentage of weight loss decreased from 66.57% to 44.731%, in addition, the composition didn't change significantly, crosslinking could also promote the stability. In terms of biocompatibility, the number of viable cells increased significantly with the days. In conclusion, the crosslinked decellularized sheep kidney extracellular matrix scaffold reduced water absorption and porosity slightly, but has a significant increase in mechanical properties, and presented excellent biocompatibility which are beneficial to cell adhesion, growth and differentiation.

Preparation and Characterization of Polylactic Acid/Nano Hydroxyapatite/Nano Hydroxyapatite/Human Acellular Amniotic Membrane (PLA/nHAp/HAAM) Hybrid Scaffold for Bone Tissue Defect Repair

Bone tissue engineering is a novel and efficient repair method for bone tissue defects, and the key step of the bone tissue engineering repair strategy is to prepare non-toxic, metabolizable, biocompatible, bone-induced tissue engineering scaffolds of suitable mechanical strength. Human acellular amniotic membrane (HAAM) is mainly composed of collagen and mucopolysaccharide; it has a natural three-dimensional structure and no immunogenicity. In this study, a polylactic acid (PLA)/Hydroxyapatite (nHAp)/Human acellular amniotic membrane (HAAM) composite scaffold was prepared and the porosity, water absorption and elastic modulus of the composite scaffold were characterized. After that, the cell-scaffold composite was constructed using newborn Sprague Dawley (SD) rat osteoblasts to characterize the biological properties of the composite. In conclusion, the scaffolds have a composite structure of large and small holes with a large pore diameter of 200 μm and a small pore diameter of 30 μm. After adding HAAM, the contact angle of the composite decreases to 38.7°, and the water absorption reaches 249.7%. The addition of nHAp can improve the scaffold's mechanical strength. The degradation rate of the PLA+nHAp+HAAM group was the highest, reaching 39.48% after 12 weeks. Fluorescence staining showed that the cells were evenly distributed and had good activity on the composite scaffold; the PLA+nHAp+HAAM scaffold has the highest cell viability. The adhesion rate to HAAM was the highest, and the addition of nHAp and HAAM could promote the rapid adhesion of cells to scaffolds. The addition of HAAM and nHAp can significantly promote the secretion of ALP. Therefore, the PLA/nHAp/HAAM composite scaffold can support the adhesion, proliferation and differentiation of osteoblasts in vitro which provide sufficient space for cell proliferation, and is suitable for the formation and development of solid bone tissue.

A biocompatible double-crosslinked gelatin/ sodium alginate/dopamine/quaterniazed chitosan hydrogel for wound dressings based on 3D bioprinting technology

Severe skin injuries can cause serious problems, which could affect the patient’s normal life, if not dealt properly in a timely and effective manner. It is an urgent requirement to develop personalized wound dressings with excellent antibacterial activity and biocompatibility to match the shape of the wound to facilitate clinical application. In this study, a bioink (GAQ) based on gelatin (Gel)/sodium alginate (SA)/ quaternized chitosan (QCS) was prepared, and GAQ hydrogel dressing grafting with dopamine (GADQ) was fabricated by an extrusion three-dimensional (3D) printing technology. QCS was synthesized by modifying quaternary ammonium group on chitosan, and its structure was successfully characterized by nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FT-IR). Our results showed that the GADQ hydrogel dressing that was double-crosslinked by EDC/ NHS and Ca2+ had good tensile strength, considerable swelling ratio, and effective antioxidation properties. It also showed that GADQ1.5% had 93.17% and 91.06% antibacterial activity against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, the relative survival ratios of fibroblast cells seeded on these hydrogels exceeded 350% after cultured for 7 days, which proved the biocompatibility of these hydrogels. Overall, this advanced 3D-printed GADQ1.5% hydrogels with effective antioxidation, excellent antibacterial activity and good biocompatibility had a considerable application potential for wound healing.

3D bioprinting of dECM/Gel/QCS/nHAp hybrid scaffolds laden with mesenchymal stem cell-derived exosomes to improve angiogenesis and osteogenesis

Craniofacial bone regeneration is a coupled process of angiogenesis and osteogenesis, which, associated with infection, still remains a challenge in bone defects after trauma or tumor resection. 3D tissue engineering scaffolds with multifunctional-therapeutic properties can offer many advantages for the angiogenesis and osteogenesis of infected bone defects. Hence, in the present study, a microchannel networks-enriched 3D hybrid scaffold composed of decellularized extracellular matrix (dECM), gelatin (Gel), quaterinized chitosan (QCS) and nano-hydroxyapatite (nHAp) (dGQH) was fabricated by an extrusion 3D bioprinting technology. And enlightened by the characteristics of natural bone microstructure and the demands of vascularized bone regeneration, the exosomes (Exos) isolated from human adipose derived stem cells as angiogenic and osteogenic factors were then co-loaded into the desired dGQH₂₀hybrid scaffold based on an electrostatic interaction. The results of the hybrid scaffolds performance characterization showed that these hybrid scaffolds exhibited an interconnected pore structure and appropriate degradability (>61% after 8 weeks of treatment), and the dGQH₂₀hybrid scaffold displayed the highest porosity (83.93 ± 7.38%) and mechanical properties (tensile modulus: 62.68 ± 10.29 MPa, compressive modulus: 16.22 ± 3.61 MPa) among the dGQH hybrid scaffolds. Moreover, the dGQH₂₀hybrid scaffold presented good antibacterial activities (against 94.90 ± 2.44% ofEscherichia coliand 95.41 ± 2.65% ofStaphylococcus aureus, respectively) as well as excellent hemocompatibility and biocompatibility. Furthermore, the results of applying the Exos to the dGQH₂₀hybrid scaffold showed that the Exo promoted the cell attachment and proliferation on the scaffold, and also showed a significant increase in osteogenesis and vascularity regeneration in the dGQH@Exo scaffoldsin vitroandin vivo. Overall, this novel dECM/Gel/QCS/nHAp hybrid scaffold laden with Exo has a considerable potential application in reservation of craniofacial bone defects.

Analysis of the Safety and Pregnancy Outcomes of Fertility-sparing Surgery in Ovarian Malignant Sex Cord-stromal Tumours: A Multicentre Retrospective Study

AIMS

To assess the difference in survival between fertility-sparing surgery (FSS) and radical surgery and explore pregnancy outcomes after FSS in stage I malignant sex cord-stromal tumours (MSCSTs).

MATERIALS AND METHODS

We carried out a multicentre retrospective cohort study on patients who were diagnosed with MSCSTs and the tumour was confined to one ovary. The patients were divided into FSS and radical surgery groups. Inverse probability of treatment weighting (IPTW) was used to balance variables between the two groups. Kaplan-Meier analysis was used to compare the difference in disease-free survival (DFS). Univariate and multivariate Cox regression analysis was used to find risk factors of DFS. Univariate logistic regression analysis was used to assess risk factors of pregnancy.

RESULTS

In total, 107 patients were included, of whom 54 (50.5%) women underwent FSS and 53 (49.5%) received radical surgery. After IPTW, a pseudo-population of 208 was determined and all of the covariates were well balanced. After a median follow-up time of 50 months (range 7-156 months), 10 patients experienced recurrence and two died. There was no significant difference in DFS between the two groups, both in unweighted (P = 0.969) or weighted cohorts (P = 0.792). In the weighted cohort, stage IC (P = 0.014), tumour diameter >8 cm (P = 0.003), incomplete staging surgery (P = 0.003) and no adjuvant chemotherapy (P < 0.001) were the four high-risk factors associated with a shorter DFS. Among 14 patients who had pregnancy desire, 11 (78.6%) women conceived successfully; the live birth rate was 76.9%. In univariate analysis, only adjuvant chemotherapy (P = 0.009) was associated with infertility.

CONCLUSIONS

On the premise of complete staging surgery, FSS is safe and feasible in early stage MSCSTs with satisfactory reproductive outcomes.

Fabrication and detection of a novel hybrid conductive scaffold based on alginate/gelatin/carboxylated carbon nanotubes (Alg/Gel/mMWCNTs) for neural tissue engineering

Carbon nanotubes (CNTs), as kinds of conductive carbon nanomaterials, were widely applied in neural tissue engineering due to their excellent electrical conductivity and good biocompatibility. In this study, the carboxyl-modified multi-walled carbon nanotubes (mMWCNTs) were introduced into sodium alginate/gelatin (Alg/Gel) scaffolds to optimize the function of the hybrid scaffolds. The Alg/Gel/mMWCNTs conductive scaffolds with mMWCNTs content of 1%, 3%, and 5% were prepared by freeze-drying, respectively. Following this, the physicochemical properties and biocompatibility of the hybrid scaffolds at different magnetic field intensities were evaluated. The conductive scaffolds were characterized by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). In general, the mMWCNTs addition improved the hydrophilic, electrical conductivity and mechanical properties of the composite scaffold, and PC12 cells showed a trend of gradual increase over culture time. Particularly, the Alg/Gel-1%C scaffold exhibited the best cell proliferation behavior. Briefly, the surface contact angle decreased from 74 ± 1° to 60 ± 3°, the electrical conductivity and compressive modulus increased to 1.32 × 10^-3 ± 2.1 × 10^-4 S/cm and 1.40 ± 0.076 Mpa, the G1 phase from 55.67 ± 1.86% to 59.77 ± 0.94% and the G2 phase from 10.32 ± 0.35% to 13.93 ± 1.26%，respectively. In the SEM images, PC12 cells were well-shaped and densely distributed. Therefore, the Alg/Gel/mMWCNTs conductive scaffold has potential as a tissue engineering scaffold in nerve regeneration.

Relationship between Social Support, Sarcopenia, and Cognitive Impairment in Chinese Community-Dwelling Older Adults

BACKGROUND

Cognitive impairment and sarcopenia have become important challenges for the growing aging population. Social support has been shown to protect against cognitive impairment, but its impact on sarcopenia remains unknown. The purpose of this study was to explore the correlation between social support, sarcopenia, and cognitive impairment in Chinese older adults.

METHOD

A multi-stage whole group sampling method was used to conduct a cross-sectional survey of 720 community-dwelling older people in Shanghai. The definition of sarcopenia was in accordance with the criteria of the Asian Working Group for Sarcopenia (AWGS) 2019. Cognitive impairment was evaluated using a computerized neuropsychological assessment device that had been previously validated. Social support was assessed using the Social Support Rate Scale. Logistic regression analyses were conducted to explore the relationship between social support cognitive impairment and sarcopenia, fully adjusting for all potential confounding factors.

RESULTS

Our study found that 230 (31.94%) of the participants had cognitive impairment and 97 (13.47%) of the participants had sarcopenia. The mean social support score was 35.10 ± 7.54. Besides, the results showed that cognitive impairment was associated with sarcopenia (OR:1.650, 95% CI: 1.048, 2.596, P=0.030) after adjusting for confounding factors. Older adults with high level social support had the lowest risk of cognitive impairment (OR: 0.297, 95% CI: 0.115, 0.680, P=0.021) and sarcopenia (OR: 0.113, 95% CI: 0.031, 0.407, P=0.001), respectively.

CONCLUSION

Our analysis revealed that high level social support was negatively associated with sarcopenia and cognitive impairment. These findings provide strong support for the health promotion effect of social networks against sarcopenia and cognitive impairment in Chinese community-dwelling older adults, with important implications for healthcare policy makers.

Curcumin nanoparticles combined with 3D printed bionic tumor models for breast cancer treatment

Compared with conventional therapeutic approaches, nanomedicines are attracting a growing interest due to their better targeting ability, higher delivery efficiency, and good water solubility. However, conventional drug efficacy assessment methods are based on a two-dimensional (2D) culture approach of single cells to obtain in vitro therapeutic effects, which may not be representative of actual tumors. Based on the above considerations, the three-dimensional (3D) cell culture models became a better choice since they can increase the complexity of in vitro systems and provide a biomimetic microenvironment that is closer to the in vivo native than two-dimensional (2D) cultures. In our study, Chinese medicine nanoparticles (CurNPs) with good water solubility and good tumor therapeutic effects were prepared by combining polymeric non-ionic surfactant (Pluronic F127) with curcumin. The hybrid scaffolds based on nano-clay, sodium alginate, and gelatin were also prepared, which showed good printability and excellent biocompatibility. We then studied the therapeutic effects of CurNPs on metastatic breast cancer using a 3D tumor model fabricated with scaffold-bound metastatic breast cancer (MDA-MB-231) cells. It was showed that the 3D cell model presented better cell proliferation effect while compared with 2D version. Additionally, there was good enhanced permeability and retention effect (EPR) effect when CurNPs entered with better accumulate in 3D cell “tumor” sites which represented more realistic response of a more real tumor treatment effect for breast cancer cells. Our study indicated that the combinational of nanomaterials with 3D cell ‘tumor’ models provided an alternative and better platform for drug screening and has great potential be used as safe and effective treatment screening for breast cancer.

A 3D bioprinted tumor model fabricated with gelatin/sodium alginate/decellularized extracellular matrix bioink

109Tissue-engineered scaffolds are more commonly used to construct three-dimensional (3D) tumor models for in vitro studies when compared to the conventional two-dimensional (2D) cell culture because the microenvironments provided by the 3D tumor models closely resemble the in vivo system and could achieve higher success rate when the scaffolds are translated for use in pre-clinical animal model. Physical properties, heterogeneity, and cell behaviors of the model could be regulated to simulate different tumors by changing the components and concentrations of materials. In this study, a novel 3D breast tumor model was fabricated by bioprinting using a bioink that consists of porcine liver-derived decellularized extracellular matrix (dECM) with different concentrations of gelatin and sodium alginate. Primary cells were removed while extracellular matrix components of porcine liver were preserved. The rheological properties of biomimetic bioinks and the physical properties of hybrid scaffolds were investigated, and we found that the addition of gelatin increased hydrophilia and viscoelasticity, while the addition of alginate increased mechanical properties and porosity. The swelling ratio, compression modulus, and porosity could reach 835.43 ± 130.61%, 9.64 ± 0.41 kPa, and 76.62 ± 4.43%, respectively. L929 cells and the mouse breast tumor cells 4T1 were subsequently inoculated to evaluate biocompatibility of the scaffolds and to form the 3D models. The results showed that all scaffolds exhibited good biocompatibility, and the average diameter of tumor spheres could reach 148.52 ± 8.02 μm on 7 d. These findings suggest that the 3D breast tumor model could serve as an effective platform for anticancer drug screening and cancer research in vitro.

Comparison of machine learning and logistic regression as predictive models for adverse maternal and neonatal outcomes of preeclampsia: A retrospective study

Introduction

Preeclampsia, one of the leading causes of maternal and fetal morbidity and mortality, demands accurate predictive models for the lack of effective treatment. Predictive models based on machine learning algorithms demonstrate promising potential, while there is a controversial discussion about whether machine learning methods should be recommended preferably, compared to traditional statistical models.

Methods

We employed both logistic regression and six machine learning methods as binary predictive models for a dataset containing 733 women diagnosed with preeclampsia. Participants were grouped by four different pregnancy outcomes. After the imputation of missing values, statistical description and comparison were conducted preliminarily to explore the characteristics of documented 73 variables. Sequentially, correlation analysis and feature selection were performed as preprocessing steps to filter contributing variables for developing models. The models were evaluated by multiple criteria.

Results

We first figured out that the influential variables screened by preprocessing steps did not overlap with those determined by statistical differences. Secondly, the most accurate imputation method is K-Nearest Neighbor, and the imputation process did not affect the performance of the developed models much. Finally, the performance of models was investigated. The random forest classifier, multi-layer perceptron, and support vector machine demonstrated better discriminative power for prediction evaluated by the area under the receiver operating characteristic curve, while the decision tree classifier, random forest, and logistic regression yielded better calibration ability verified, as by the calibration curve.

Conclusion

Machine learning algorithms can accomplish prediction modeling and demonstrate superior discrimination, while Logistic Regression can be calibrated well. Statistical analysis and machine learning are two scientific domains sharing similar themes. The predictive abilities of such developed models vary according to the characteristics of datasets, which still need larger sample sizes and more influential predictors to accumulate evidence.

Injectable carbon nanotube-functionalized hydrogel as a tool for cardiac tissue engineering

Background/Introduction

Heart failure (HF) is an expensive major public health problem in the United States and around the world (1). The current treatments for HF are aimed at reducing symptoms, slowing disease progression, and reducing mortality and not aimed at repairing heart muscle or restoring function. Furthermore, even with these treatments, approximately half of patients with HF will die within 5 years of diagnosis (2). Cardiac transplantation remains the only definitive treatment for those affected with end-stage HF, but availability of donor hearts remains a major limitation (3).

Purpose

The ability of the adult heart to regenerate cardiomyocytes (CMs) lost after injury is limited, generating interest in developing tissue engineering therapies to avoid progression towards HF. Rigid carbon nanotubes (CNTs) scaffolds have been used to improve CMs viability, proliferation, and maturation (4), but require undesirable invasive surgeries for implantation. To overcome this limitation, we engineered an injectable reverse thermal gel (RTG) functionalized with CNTs (RTG-CNT) that transitions from a liquid-solution to a gel-based matrix shortly after reaching body temperature allowing for a liquid-based delivery rapidly followed by a stable-gel localization (5).

Methods and results

Here we show experimental evidences the RTG-CNT hydrogel, used as a three-dimensional (3D) niche to culture human induced pluripotent stem cells (hiPSC)-CMs, promotes hiPSC-CMs alignment and elongation with increased Cx43 localization and improved contraction function when compared with traditional two-dimensional (2D) fibronectin controls and plain 3D RTG system without CNTs. Moreover, the short-term (4-week) biocompatibility of the RTG-CNT hydrogel was also assessed in a mouse model (intracardial injection). The results confirmed that the RTG-CNT hydrogel is well tolerated by the cardiac tissue.

Conclusion

Our results indicated that the injectable RTG-CNT hydrogel has the potential to be used as a minimally invasive tool for cardiac tissue engineering efforts.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): NATIONAL HEART, LUNG, AND BLOOD (NHLBI) INSTITUTE

3-Dimensional mesothelioma spheroids provide closer to natural pathophysiological tumor microenvironment for drug response studies

Traditional studies using cancer cell lines are often performed on a two-dimensional (2D) cell culture model with a low success rate of translating to Phase I or Phase II clinical studies. In comparison, with the advent of developments three-dimensional (3D) cell culture has been championed as the latest cellular model system that better mimics in vivo conditions and pathological conditions such as cancer. In comparison to biospecimens taken from in vivo tissue, the details of gene expression of 3D culture models are largely undefined, especially in mesothelioma – an aggressive cancer with very limited effective treatment options. In this study, we examined the veracity of the 3D mesothelioma cell culture model to study cell-to-cell interaction, gene expression and drug response from 3D cell culture, and compared them to 2D cell and tumor samples. We confirmed via SEM analysis that 3D cells grown using the spheroid methods expressed highly interconnected cell-to-cell junctions. The 3D spheroids were revealed to be an improved mini-tumor model as indicated by the TEM visualization of cell junctions and microvilli, features not seen in the 2D models. Growing 3D cell models using decellularized lung scaffold provided a platform for cell growth and infiltration for all cell types including primary cell lines. The most time-effective method was growing cells in spheroids using low-adhesive U-bottom plates. However, not every cell type grew into a 3D model using the the other methods of hanging drop or poly-HEMA. Cells grown in 3D showed more resistance to chemotherapeutic drugs, exhibiting reduced apoptosis. 3D cells stained with H&E showed cell-to-cell interactions and internal architecture that better represent that of in vivo patient tumors when compared to 2D cells. IHC staining revealed increased protein expression in 3D spheroids compared to 2D culture. Lastly, cells grown in 3D showed very different microRNA expression when compared to that of 2D counterparts. In conclusion, 3D cell models, regardless of which method is used. Showed a more realistic tumor microenvironment for architecture, gene expression and drug response, when compared to 2D cell models, and thus are superior preclinical cancer models.

Exosomes: Small Vesicles with Important Roles in the Development, Metastasis and Treatment of Breast Cancer

Breast cancer (BC) has now overtaken lung cancer as the most common cancer, while no biopredictive marker isolated from biological fluids has yet emerged clinically. After traditional chemotherapy, with the huge side effects brought by drugs, patients also suffer from the double affliction of drugs to the body while fighting cancer, and they often quickly develop drug resistance after the drug, leading to a poor prognosis. And the treatment of some breast cancer subtypes, such as triple negative breast cancer (TNBC), is even more difficult. Exosomes (Exos), which are naturally occurring extracellular vesicles (EVs) with nanoscale acellular structures ranging in diameter from 40 to 160 nm, can be isolated from various biological fluids and have been widely studied because they are derived from the cell membrane, have extremely small diameter, and are widely involved in various biological activities of the body. It can be used directly or modified to make derivatives or to make some analogs for the treatment of breast cancer. This review will focus on the involvement of exosomes in breast cancer initiation, progression, invasion as well as metastasis and the therapeutic role of exosomes in breast cancer.

[Prognosis and fertility outcomes of patients with borderline ovarian tumors after fertility-sparing surgery]

Objective: To explore the clinical prognosis and fertility outcomes in patients with borderline ovarian tumors (BOT) who underwent fertility-sparing surgery, and evaluate the related risk factors. Methods: The study examined the clinicopathological characteristics of 280 patients diagnosed with BOT from Qilu Hospital of Shandong University between January 2009 and December 2019. According to the surgery plan, the patients were divided into the fertility-sparing group (167 cases) and the radical surgery group (113 cases). The information of the patients' age, preoperative serum CA-125 level, surgery method, pathological type, FIGO stage (2014), tumor location, and whether focal canceration combined were collected. The Kaplan-Meier method was used to compare disease-free survival (DFS) between the fertility-sparing surgery group and the radical surgery group. The univariate and multivariate Cox proportional hazard regression analysis was used to explore high-risk factors associated with DFS. Results: A total of 280 BOT patients were identified in the study, with a median age of 35.0 (26.0, 51.0) years old. The median follow-up time was 55.2 (34.7, 79.3)months. 25 patients (15.0%) developed recurrence in the fertility-sparing surgery group, 11 patients (8.7%) developed recurrence in the radical surgery group. There was no significant difference in 5-year DFS rate between the two groups (84.4% vs 90.1%, P=0.223). Only FIGO stage was found to be related to DFS through the univariable and multivariable Cox proportional hazard regression analysis, and patients with FIGO Ⅱ/Ⅲ had higher risk of recurrence [HR (95%CI) 2.872(1.283-6.431)] (P=0.010); Fertility-sparing surgery does not increase the recurrence risk of BOT patients (P=0.116). Pregnancies were reported in 39 patients (54.2%), among whom 37 patients gave birth successfully, and 2 patients selected to terminate pregnancy. Conclusions: The fertility-sparing surgery does not increase the risk of recurrence in BOT patients, and patients who underwent the fertility-sparing surgery have a favorable outcome. FIGO stage is the independent risk factor of DFS in BOT patients.

Gelatin/sodium alginate hydrogel-coated decellularized porcine coronary artery to construct bilayer tissue engineered blood vessels

Cardiovascular diseases and vascular trauma can be commonly found in the population. Scholars worldwide hope to develop small-diameter vascular grafts that can replace autologous vessels for clinical use. Decellularized blood vessels can retain the original morphology, structure, and physical properties of blood vessels, which is conducive to cell growth, proliferation, and differentiation. In this study, porcine coronary arteries (PCAs) were decellularized to prepare decellularized porcine coronary artery (DPCA), and bilayer hybrid scaffolds were prepared by coating gelatin and sodium alginate mixed hydrogel of seven different proportions and combined with mouse fibroblasts (L929 cells) to study the construction of tissue engineering vessels in vitro. The obtained bilayer hybrid scaffolds were 3-7 cm in length, 5 mm in external diameter, and 1 mm in average wall thickness. All seven bilayer hybrid scaffolds showed good biocompatibility after cell inoculation. Compared with 2D culture, cells on 3D scaffolds grew relatively slowly in the first 4 days, and the number of cells proliferated rapidly at 7 days. In the same culture days, different concentrations of hydrogel also had an impact on cell proliferation. With the increase of hydrogel content, cells on the 3D scaffold formed cell colonies faster. The results showed that the scaffold had good biocompatibility and could meet the needs of artificial blood vessel construction.

Decellularized Pig Kidney with a Micro-Nano Secondary Structure Contributes to Tumor Progression in 3D Tumor Model

In spite of many anti-cancer drugs utilized in clinical treatment, cancer is still one of the diseases with the highest morbidity and mortality worldwide, owing to the complexity and heterogeneity of the tumor microenvironment. Compared with conventional 2D tumor models, 3D scaffolds could provide structures and a microenvironment which stimulate native tumor tissues more accurately. The extracellular matrix (ECM) is the main component of the cell in the microenvironment that is mainly composed of three-dimensional nanofibers, which can form nanoscale fiber networks, while the decellularized extracellular matrix (dECM) has been widely applied to engineered scaffolds. In this study, pig kidney was used as the source material to prepare dECM scaffolds. A chemical crosslinking method was used to improve the mechanical properties and other physical characteristics of the decellularized pig kidney-derived scaffold. Furthermore, a human breast cancer cell line (MCF-7) was used to further investigate the biocompatibility of the scaffold to fabricate a tumor model. The results showed that the existence of nanostructures in the scaffold plays an important role in cell adhesion, proliferation, and differentiation. Therefore, the pig kidney-derived matrix scaffold prepared by decellularization could provide more cell attachment sites, which is conducive to cell adhesion and proliferation, physiological activities, and tumor model construction.

Factors influencing the effective management of diabetes during humanitarian crises in low- and middle-income countries: a systematic review

OBJECTIVES

The management of non-communicable chronic diseases such as diabetes mellitus is often poor in humanitarian crisis settings. Poor disease management can have serious long-term consequences. This review sought to identify studies that explored the effectiveness of interventions and the determinants that may improve the management of diabetes in the humanitarian context.

STUDY DESIGN

A systematic review was conducted of all types of studies that implemented diabetes programmes in humanitarian settings.

METHODS

MEDLINE, Embase, CINAHL and Web of Science were searched for relevant articles using multiple search terms for relevant studies published in English between 2000 and June 2020. Quality assessments using valid tools, were conducted. A narrative synthesis of the findings was then performed.

RESULTS

The search yielded 550 citations. After de-duplicating and screening, 19 studies were eligible for inclusion. Most studies were conducted in the Middle East (74%), Asia (16%) and Africa (10%). The interventions reported to improved diabetes care included the mHealth tool, intensive lifestyle intervention, task-shifting, psychosocial support, distribution of glucometers and comprehensive care. Insufficient drug supply, out-of-pocket cost, the complexity of insulin therapy and low adherence to guidelines were identified as barriers.

CONCLUSION

There is a paucity of evidence on optimal diabetes care in acute crisis and natural disaster settings. The review was constrained by the low quality of the studies included. Nevertheless, it is likely that mHealth can be feasibly utilised, as educational SMS messages are cost-effective and electronic medical records can enhance disease monitoring. In addition, a multidisciplinary approach to care improves glycaemic control and is desirable due to the multifaceted nature of the disease and management required. Several key barriers have been identified that need to be tackled. Overall, the evidence base for diabetes care in humanitarian settings remains sparse, and further research is needed.

A biological functional hybrid scaffold based on decellularized extracellular matrix/gelatin/chitosan with high biocompatibility and antibacterial activity for skin tissue engineering

Nowadays, decellularized extracellular matrix (dECM) has received widespread attention due to its diversity in providing the unique structural and functional components to support cell growth, and finding material with good biocompatibility and anti-infection capability for skin tissue engineering is still a challenge. In this study, a novel dECM/Gel/CS scaffold with appropriate mechanical strength, good antibacterial activity and high biocompatibility was prepared using a one-pot method. The results showed that the immune components such as cells and DNA (about 98.1%) were successfully removed from the porcine skin tissue. The dECM/Gel/CS scaffolds exhibited an interconnected pore structure and had a high porosity (>90%) to promote cell growth. Moreover, the appropriate elastic modulus (≥482.17 kPa) and degradability (≥80.04% for 15 days) of the scaffolds offered stout "houses" for cell proliferation and suitable degradation rate to match the new tissue formation in skin tissue engineering. Furthermore, the addition of chitosan endowed the scaffold with good antibacterial activity, water and protein absorption capacity to avoid wound infection, and maintain the moisture and nutrition balance. In vitro cytocompatibility studies showed that the presence of dECM effectively enhanced the cell proliferation. Overall, the advanced dECM/Gel/CS scaffold has considerable potential to be applied in skin tissue engineering.

Validation of the mechano-bactericidal mechanism of nanostructured surfaces with finite element simulation

The mechano-bactericidal property of nanostructured surfaces has become the focus of intensive research toward the development of a new generation of antibacterial surfaces, especially in the current era of spreading antibiotic resistance. However, the mechanisms underlying nanostructured surfaces mechanically damaging bacteria remain unclear, which ultimately limits translational potential toward real-world applications. Using finite element simulation technique, we developed the three-dimensional thin wall with turgor pressure finite element model (3D-TWTP-FEM) of bacterial cell and verified the reliability of this model by the AFM indentation experiment simulation of the cell, and the cell model is able to simulate suspended bacterial cell and the process of cell adhering to the flat and nanopillar surfaces. Since bacterial cells suffer greater stress and deformation on the nanopillar surfaces, a two-stage model of the elastic and creep deformation stage of the cells on the nanostructured surfaces was developed. The calculations show that the location of the maximum stress/strain on the cells adhered to the nanopillar surfaces is at the liquid-cell-nanopillar three phase contact line. The computational results confirmed the ability of nanostructured surfaces to mechanically lyse bacteria and gave the effect of nanopillar geometry on the efficiency and speed of bacterial cell rupture. This study provides fundamental physical insights into how nanopillar surfaces can serve as effective and fast mechanical antimicrobial materials.

Cytotoxicity and growth-inhibiting activity of Astragalus polysaccharides against breast cancer via the regulation of EGFR and ANXA1

Astragalus polysaccharide (APS) has been frequently used as an adjuvant agent responsible for its immunoregulatory activity to enhance efficacy and reduce toxicity of chemotherapy used in the management of breast cancer. However, the other synergism mechanism of APS remains unclear. This study was performed to evaluate the potential targets and possible mechanism behind APS in vivo direct anti-tumor activity on breast cancer. Multiple biological detections were conducted to investigate the protein and mRNA expression levels of key targets. In total, 116 down-regulated and 73 up-regulated differential expressed genes (DEGs) were examined from 7 gene expression datasets. Top ten hub genes were obtained in four typical protein-protein interaction (PPI) network of DEGs involved in each specific biological process (BP, cell cycle, cell proliferation, cell apoptosis and death) that was related to inhibitory activity of APS in vitro against breast cancer cell lines. Four common DEGs (EGFR, ANXA1, KIF14 and IGF1) were further identified in the above four BP-PPI networks, among which EGFR and ANXA1 were the hub genes that were potentially linked to the progression of breast cancer. The results of biological detections indicated that the expression of EGFR in breast cancer cells was down-regulated, while the expression of ANXA1 was markedly increased in response to APS. In conclusion, the present study may provide potential molecular therapeutic targets and a new insight into the mechanism of APS against breast cancer.

Low-Temperature Hydrothermal Synthesis of Novel 3D Hybrid Nanostructures on Titanium Surface with Mechano-bactericidal Performance

Titanium is extensively employed in modern medicines as orthopedic and dental implants, but implant failures frequently occur because of bacterial infections. Herein, three types of 3D nanostructured titanium surfaces with nanowire clusters (NWC), nanowire/sheet clusters (NW/SC) and nanosheet clusters (NSC), were fabricated using the low-temperature hydrothermal synthesis under normal pressure, and assessed for the sterilization against two common human pathogens. The results show that the NWC and NSC surfaces merely display good bactericidal activity against Escherichia coli, whereas the NW/SC surface represents optimal bactericidal efficiency against both Escherichia coli (98.6 ± 1.23%) and Staphylococcus aureus (69.82 ± 2.79%). That is attributed to the hybrid geometric nanostructure of NW/SC, i.e., the pyramidal structures of ∼23 nm in tip diameter formed with tall clustered wires, and the sharper sheets of ∼8 nm in thickness in-between these nanopyramids. This nanostructure displays a unique mechano-bactericidal performance via the synergistic effect of capturing the bacteria cells and penetrating the cell membrane. This study proves that the low-temperature hydrothermal synthesized hybrid mechano-bactericidal titanium surfaces provide a promising solution for the construction of bactericidal biomedical implants.

Evaluation of anti-tumor effects of crocin on a novel 3D tissue-engineered tumor model based on sodium alginate/gelatin microbead

Crocin, as one of the biologically active components of saffron, has anti-inflammatory, anti-oxidant, anti-depressant and auxiliary anti-tumor effects. Studies have shown that crocin could promote breast cancer cell apoptosis. However, conventional methods are mainly based on two-dimensional (2D) cell culture models, which are difficult to reproduce the tumor environment in vivo due to space constraints. In this study, we prepared a three-dimensional (3D) cell model in vitro based on sodium alginate/gelatin to evaluate the inhibitory effect of crocin on MCF-7 cells, which could bridge the gap in crocin drug evaluation between 2D and 3D cell model in vitro. Different from the 2D culture, the cells were found to aggregate in a spherical shape in the 3D microgel beads. And the CCK-8 assay showed that the growth of MCF-7 cells exposed to crocin was inhibited in a time-related and concentration-related manner. Compared with 2D culture (IC₅₀ that MCF-7 cells treated with crocin at 24 h, 48 h, 72 h: 3.68, 2.55 and 1.53 mg/mL, respectively), the IC₅₀ value of 3D culture (IC₅₀ that MCF-7 cells treated with crocin at 24 h, 48 h, 72 h: 10.12, 6.89 and 6.64 mg/mL, respectively) was significantly increased by 2.77, 2.70, 4.34 times, respectively. Besides, live/dead staining and scanning electron microscope (SEM) revealed that the 2D cultured cells shrank and ruptured after crocin treatment, and the number of living cells was considerably reduced; the size of the cell colonies in the 3D microgel beads decreased.

Evaluation of inhibitory effects of geniposide on a tumor model of human breast cancer based on 3D printed Cs/Gel hybrid scaffold

Traditional Chinese medicine therapy, which can serve as adjuvant therapy for cancer treatment, has no obvious side effects on the human body. Geniposide (GEN), one of the main iridoid glycosides in gardenia fruit, has been widely reported to have anti-cancer effects. In this study, we aimed to inspect whether GEN could inhibit proliferation and promote the apoptosis of human breast cancer cells (MCF-7). In order to better predict the efficacy of GEN, we have prepared the Cs/Gel composite scaffolds by 3D printing technology to mimic the MCF-7 cell growth microenvironment. The prepared Cs/Gel scaffold has good mechanical properties and biocompatibility, which can provide a more accurate platform for drug screening. The semi-inhibitory concentration (IC50) evaluated by CCK-8 assay was 16.06 mg/mL (24 h), 14.85 mg/mL (48 h), and 13.14 mg/mL (72 h). After exposed to GEN for 48 h, the cancer cell survival rate reduced from 69.15 ± 2.86% (13 mg/mL) to 20.97 ± 3.24% (16 mg/mL). Although the inhibitory effect was weaker in the 3D culture system, it also managed to inhibit cell proliferation and induce cell apoptosis. Besides, Live/Dead staining, Hematoxylin-Eosin (H&E) staining and SEM evaluation were also conducted to estimate the anti-cancer effect of GEN in 2D and 3D cultures. The results indicate that GEN has an anti-cancer effect based on a time- and dose-dependent manner.

De-escalation strategy with half-dose prasugrel or ticagrelor on pharmacodynamics and outcome in East Asians patients with acute coronary syndrome

Background

East Asians treated with potent P2Y12 inhibitors (prasugrel or ticagrelor) are exposed to more potent platelet inhibitory response. Whether half-dose de-escalation strategy would be benefit for chronic antiplatelet strategy in East Asian patients with acute coronary syndrome (ACS) remain uncertain.

Method

In half-dose de-escalation strategy, 129 Korean ACS patients were assigned to receive standard-dose potent P2Y12 inhibitors (n=86, prasugrel [n=38], ticagrelor [n=48]), followed by half-dose reduction at 1 month for maintenance, and was compared to clopidogrel (n=43) as control. The primary safety outcome was any clinically significant bleeding according to BARC (Bleeding Academic Research Consortium) criteria at 12 months. The pharmacodynamic response is accessed by VerifyNow P2Y12 reaction unit (PRU) at 1 month and 3 months post PCI.

Results

Ticagrelor achieved significantly lower PRU (7 [4–32] vs. 11 [5–76] vs. 167 [97–212]) than prasugrel and clopidogrel, resulting OPR rate 0% vs. 21.6% vs. 58.5%, respectively at 1 month post PCI. Similar results were observed at 3 months (PRU 12 [6–43] in ticagrelor vs. 88 [58–148] in prasugrel vs. 169 [107–199] in clopidogrel), with OPR rate 7.1% vs. 51.5% vs. 65.9%, respectively. At 12 months, the incidence of BARC type-1 or -2 bleeding was significantly higher in potent P2Y12 inhibitors (37.5% in ticagrelor, 34.2% in prasugrel) than in clopidogrel (36.0 vs. 14.0%; HR, 2.86; 95% CI, 1.19–6.87; p=0.018).

Conclusion

In Korean ACS patients, pharmacodynamic response (OPR rate) with half-dose prasugrel appears comparable to that with clopidogrel, whereas ticagrelor still exhibit potent platelet inhibition either standard or half doses. De-escalation strategy with half-dose potent P2Y12 inhibitor was associated with higher incidence of clinically insignificant bleeding compared with clopidogrel. Optimal dose reduction strategies in potent P2Y12 inhibitors to balance safety and effectiveness remain uncertain, and require further studies.

Pharmcodynamics to oral P2Y12 inhibitors

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): National Research Foundation of Korea

Pharmacodynamic comparison of optimal platelet reactivity by multiple platelet function tests in Korean acute coronary syndrome patients with half-dose ticagrelor or prasugrel treatment

Background

East Asians treated with potent P2Y12 inhibitors, prasugrel or ticagrelor exhibit more potent platelet inhibition than clopidogrel. Whether half-dose de-escalation strategy would improve optimal platelet reactivity at maintenance in East Asian patients with acute coronary syndrome (ACS) remains uncertain.

Method

In de-escalation strategy single center study, eligible Korean ACS patients (n=96) were assigned to receive standard-dose ticagrelor (n=33), prasugrel (n=28), followed by half-dose reduction at 1 month for maintenance, and clopidogrel (n=35) as control. Platelet reactivity was measured by VerifyNow, light transmittance aggregometry (LTA) and multiple electrode aggregometry (MEA). The investigators aim to compare optimal platelet reactivity status (OPR, defined as 85–208 P2Y12 reaction unit [PRU] for VerifyNow (VN), 16%–47% for LTA and 19–46 U for MEA) among 3 different platelet function tests at 3 months post PCI.

Results

At 3 months, ticagrelor achieved significantly lower PRU (17 [6–51] vs. 95 [61–151] vs. 172 [111–204]) than prasugrel and clopidogrel, resulting OPR rate 10% vs. 57.7% vs. 60.0%, respectively. Similar results were observed at LTA method (2% [0–12] in ticagrelor vs. 18% [13–22] in prasugrel vs. 18% [11–30] in clopidogrel), with OPR rate 11.8% vs. 69.2% vs. 50.0%, respectively. However, platelet reactivity was similar by MEA method (16 [13–20] in ticagrelor vs. 17 [13–22] in prasugrel vs. 19 [14–28] in clopidogrel), with OPR rate 33.3% vs. 40.0% vs. 42.0%, respectively (all p&gt;0.005). Among the three tests, resulting higher correlation between VN and LTA (r=0.745), MEA and LTA vs. MEA and VN showed lower correlations (r=0.412 and r=0.303). (Fig.)

Conclusion

In Korean ACS patients with half-dose de-escalation strategy after 1 month, OPR rate in ticagrelor is still rare during 3-month treatment by VN and LTA methods, however, prasugrel appears comparable to clopidogrel. VN/LTA might overestimate platelet function than MEA or MEA underestimate OPR rate than VN/LTA.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): National Research Foundation of Korea

Canadian perspective on managing multiple myeloma during the COVID-19 pandemic: lessons learned and future considerations

The coronavirus disease 2019 (covid-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 has necessitated changes to the way patients with chronic diseases are managed. Given that patients with multiple myeloma are at increased risk of covid-19 infection and related complications, national bodies and experts around the globe have made recommendations for risk mitigation strategies for those vulnerable patients. Understandably, because of the novelty of the virus, many of the proposed risk mitigation strategies have thus far been reactionary and cannot be supported by strong evidence. In this editorial, we highlight some of the risk mitigation strategies implemented at our institutions across Canada during the first wave of covid-19, and we discuss the considerations that should be made when managing patients during the second wave and beyond.