BackgroundDespite the high cure rate of T cell acute lymphoblastic leukemia (T-ALL), drug resistance to chemotherapy remains a significant clinical problem. Bone marrow mesenchymal stem cells (MSCs) protect leukemic cells from chemotherapy, but the underlying mechanisms are poorly understood. In this study, we aimed to uncover the mechanism of MSC-induced chemoresistance in T-ALL cells, thus providing a promising clinical therapy target.MethodsCell viability was determined using the viability assay kit CCK-8. The mitochondrial ROS levels were detected using the fluorescent probe MitoSOX™ Red, and fluorescence intensity was measured by flow cytometry. In vitro, MSCs and Jurkat cells were cocultured. MSCs were labeled with green fluorescent protein (GFP), and Jurkat cells were labeled with the mitochondria-specific dye MitoTracker Red. Bidirectional mitochondrial transfer was detected by flow cytometry and confocal microscopy. The mechanism of mitochondria transfer was analyzed by inhibitor assays. Transcripts related to Jurkat cell/MSC adhesion in the coculture system were assessed by qRT-PCR. After treatment with a neutralizing antibody against a key adhesion molecule, mitochondria transfer from Jurkat cells to MSCs was again detected by flow cytometry and confocal microscopy. Finally, we verified our findings using human primary T-ALL cells cocultured with MSCs.ResultsChemotherapeutic drugs caused intracellular oxidative stress in Jurkat cells. Jurkat cells transfer mitochondria to MSCs but receive few mitochondria from MSCs, resulting in chemoresistance. This process of mitochondria transfer is mediated by tunneling nanotubes, which are protrusions that extend from the cell membrane. Moreover, we found that most Jurkat cells adhered to MSCs in the coculture system, which was mediated by the adhesion molecule ICAM-1. Treatment with a neutralizing antibody against ICAM-1 led to a decreased number of adhering Jurkat cells, decreased mitochondria transfer, and increased chemotherapy-induced cell death.ConclusionsWe show evidence that mitochondria transfer from Jurkat cells to MSCs, which is mediated by cell adhesion, may be a potential therapeutic target for T-ALL treatment.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0554-z) contains supplementary material, which is available to authorized users.

Four-dimensional (4D) bioprinting of cell-laden constructs with programmable shape-morphing structures has gained increasing attention in the field of biofabrication and tissue engineering. Currently, most of the widely used materials for 4D printing, including N-isopropylacrylamide-based polymers, are not commonly used in bioinks for cell-laden bioprinting. Herein, we propose a facile approach to create cell-laden constructs with near-infrared (NIR)-triggered shape morphing using bioinks based on alginate (the most widely used bioink for cell-laden bioprinting). Three-dimensional (3D) printed bilayered scaffolds with orthogonal structures using concentrated alginate/polydopamine (PDA) inks (14–18 wt%) showed a change in folded shape during NIR-induced dehydration. The deformation angle of the scaffold could be controlled by laser power, irradiation time and the designed patterns of the printed alginate/PDA struts in scaffolds. Then, 3D printed biphasic scaffolds consisting of alginate/PDA and cell-laden hydrogels exhibited programmable shape change under NIR stimulation. Scaffolds were able to maintain their deformed structures, and the printed cells in hydrogels retained high viability during culture in medium for at least 14 days. The biocompatible and commonly used hydrogel bioinks, NIR-triggered shape-morphing structures and maintenance of the deformed shape in the medium give this facile approach great potential for application in the field of 4D bioprinting and 4D biofabrication of artificial tissues and organs.

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Pancreatic neuroendocrine tumor (pancreatic NETs), is an important cause of cancer‐related death worldwide. No study has rigorously explored the impact of ethnicity on pancreatic NETs. We aimed to demonstrate the relationship between ethnicity and the survival of patients with pancreatic NETs. We used the SEER database to identify patients with pancreatic NETs from 2004 to 2013. Kaplan–Meier methods and Cox proportional hazard models were used to evaluate the impact of race on survival in pancreatic NETs patients. A total of 3850 patients were included: 3357 Non‐Blacks, 493 Blacks. We stratified races as “Black” and “White/Other.” Blacks were more likely to be diagnosed with later stages of tumors (P = 0.021). As for the treatment, the access to surgery seemed to be more limited in Blacks than non‐Black patients (P = 0.012). Compared with non‐Black patients, Black patients have worse overall survival (OS) (HR = 1.17, 95% CI: 1.00–1.37, P = 0.046) and pancreatic neuroendocrine tumors specific survival (PNSS) (HR = 1.22, 95% CI: 1.01–1.48, P = 0.044). Multivariate Cox analysis identified that disease extension at the time of diagnosis and surgical status contributed to the ethnical survival disparity. Black patients whose stages at diagnosis were localized had significantly worse OS (HR = 2.09, 95% CI: 1.18–3.71, P = 0.011) and PNSS (HR = 3.79, 95% CI: 1.62–8.82, P = 0.002). As for the patients who did not receive surgery, Blacks also have a worse OS (HR = 1.18, 95% CI: 1.00–1.41, P = 0.045). The Black patients had both worse OS and PNSS compared to non‐Black patients. The restricted utilization of surgery, and the advanced disease extension at the time of diagnosis are the possible contributors to poorer survival of Blacks with pancreatic NETs.

Thermosensitive hydrogels are very important biomaterials used in drug delivery systems (DDSs), which gained increasing attention of researchers. Thermosensitive hydrogels have great potential in various applications, such as drug delivery, cell encapsulation, tissue engineering, and etc. Especially, injectable thermosensitive hydrogels with lower sol-gel transition temperature around physiological temperature have been extensively studied. By in vivo injection, the hydrogels formed non-flowing gel at body temperature. Upon incorporation of pharmaceutical agents, the hydrogel systems could act as sustained drug release depot in situ. Injectable thermosensitive hydrogel systems have a number of advantages, including simplicity of drug formulation, protective environment for drugs, prolonged and localized drug delivery, and ease of application. The objective of this review is to summarize fundamentals, applications, and recent advances of injectable thermosensitive hydrogel as DDSs, including chitosan and related derivatives, poly(N-isopropylacrylamide)-based (PNIPAAM) copolymers, poly(ethylene oxide)/poly(propylene oxide) (PEO/PPO) copolymers and its derivatives, and poly(ethylene glycol)/ biodegradable polyester copolymers.

BackgroundRapid diagnostic tests (RDTs) have become an essential tool in the contemporary malaria control and management programmes in the world. This study aims to evaluate the performance of two commonly used RDTs for malaria diagnosis in the China-Myanmar border area.MethodsA total 606 febrile patients in the China-Myanmar border were recruited to this study and were diagnosed for malaria infections by microscopy, two RDTs tests (Pf/Pan device, and Pv/Pf device) and nested PCR.ResultsMalaria parasites were found in 143 patients by microscopy, of which 51, 73, and 19 were Plasmodium falciparum, Plasmodium vivax and P. falciparum/P. vivax mixed infections, respectively. Compared to microscopy, the sensitivity of the Pf/Pan device was 88.6% for P. falciparum and 69.9% for P. vivax with the specificity of 90.4%. For a subset of 350 patients, the sensitivity of the Pf/Pan device and Pv/Pf device for detection of P. falciparum was 87.5% and 91.7%, respectively; and for detection of P. vivax was 72.0% and 73.8%, respectively. The specificity of the Pf/Pan device and Pv/Pf device was 94.3% and 96.5%, respectively. Nested PCR detected malaria parasites in 174 of 606 samples, of which 67, 79, two and 26 were P. falciparum, P. vivax, P. ovale and P. falciparum/P. vivax mixed infections, respectively. Compared to nested PCR, all other methods had sensitivity below 80%, suggesting that a significant number of cases were missed.ConclusionsCompared to PCR, both microscopy and RDTs had lower sensitivities. RDTs had similar performance to microscopy for P. falciparum diagnosis, but performed worse for P. vivax diagnosis. Other RDT products should be selected with higher sensitivity (and good specificity) for both P. falciparum and P. vivax diagnosis.

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Three‐dimensional (3D) bioprinting is a promising technology to produce cell‐laden constructs via patterning living cells, biological factors and biomaterials in a precisely controlled manner. However, it is still a challenge to fabricate human tissues/organs with biological functions for clinical application via 3D bioprinting. Several key issues should be carefully addressed to overcome this challenge, specifically the construction of biomimetic microenvironments. 3D printing has been broadly demonstrated the ability to create structures mimicking native tissues, while it also has the capability to produce biomimetic microenvironments. Therefore, this review will give an overview of the current advances in the art of building and controlling hydrogel‐based biomimetic microenvironments in cells‐laden 3D bioprinting, which are classified by their physical, chemical, and biological features. In the end, we will elaborate the outlook of 3D bioprinting of biomimetic microenvironment. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1695–1705, 2019.