Yuji Nashimoto

The tumor microenvironment plays a pivotal role in tumor development, harboring elements such as endothelial cells, immune cells, fibroblasts, and soluble factors such as transforming growth factor-β (TGF-β) family. TGF-β family regulates cell development and promotes tumor invasion, metastasis, angiogenesis, and endothelial-to-mesenchymal transition (EndoMT). Here, we investigate the effects of TGF-β signaling on vascular remodeling using a three-dimensional (3D) vascular network in a microfluidic device. Using both a co-culture (3D-Co) and simplified endothelial monoculture (3D-CM), we demonstrate that TGF-β signaling reduces the quality and functionality of the vasculature by regressing them. In addition, we observed the upregulation of EndoMT-related markers in mRNA and protein expressions, suggesting the induction of EndoMT in 3D vascular networks. The increased vascular permeability stimulated by TGF-β2 also supports the loss of endothelial identity in the 3D-Co. Transcriptomic analysis revealed the coordinated activation of pathways associated with cell migration and EndoMT, along with the suppression of cell cycle progression. A comparative analysis of two-dimensional (2D) and 3D cultures revealed a fundamentally distinct endothelial response to TGF-β2 in the 3D context, including metabolic reprogramming. These findings demonstrate that the 3D microenvironment critically modulates endothelial responses to TGF-β and enables the emergence of vascular phenotypes not captured in 2D systems. This study provides a more physiologically relevant platform to investigate endothelial dysfunction and vascular remodeling.

Asthma poses a substantial global health burden, affecting approximately 300 million individuals worldwide. However, accurate diagnosis of asthma remains a significant clinical challenge, primarily due to the heterogeneous and dynamic nature of the disease and the lack of a single definitive biomarker. These limitations motivate the continued development of advanced diagnostic strategies, particularly those based on exhaled breath analysis. Since both NO and H2S have been identified as breath biomarkers of asthma, the simultaneous analysis of NO and H2S in the exhaled breath using a gas sensor array composed of ultrasensitive single sensors may enable more accurate clinical diagnosis. In this study, a gas sensor array consisting of an ultrasensitive NO sensor and an ultrasensitive H2S sensor, each with a detection limit of 5 ppb, was constructed. Clinically, 76 exhaled breath samples collected from 36 asthma patients and 40 healthy controls were analyzed using the proposed gas sensor array. Two diagnostic models for asthma were constructed using the machine learning analysis algorithm: one based on the selection and analysis of hand-crafted (expert-defined) features and the other based on analyzing the integrated hand-crafted features with automatically learned features. The two models achieved accuracies, sensitivities, and specificities of 93, 92, and 95% and 91, 89, and 93%, respectively, with corresponding area under the curve values of 0.98 and 0.97. These results demonstrate the strong capability of the proposed gas sensor array for accurate asthma diagnosis and highlight its significant potential for practical implementation in clinical settings.

Chronic diseases require regular medication intake over a long period of time, which induce a poor adherence to treatment by patients. To overcome this limitation, new implantable drug delivery systems (IDDS) are being developed to allow optimized local drug release over a long period (often few months or years), reducing side effects and improving patient compliance. In this review, we provide an overview on IDDS that have been fabricated for the delivery of drugs to skeletal muscles, and to eyes. We organizes this review by IDDS types with an emphasis on recent studies conducted between 2019 and 2024. After an introduction on IDDS (including IDDS market, method of fabrication, materials used, classification, and applications), we discuss their great diversity, fabrication procedures, drug release analysis, and their operational time. Our main goal is to provide a comprehensive overview of various types of IDDS used for skeletal muscles and eyes and discuss the evolution of these systems. We concludes the review with future developments and perspectives.

Endothelial metabolism is closely linked to vascular function and is often altered in response to pathological stimuli. Although vascular microphysiological systems (MPS) offer a promising in vitro platform for modeling vascular environments, the integration of real-time metabolic monitoring remains technically challenging. Enzyme-based electrochemical sensors are well-suited for detecting metabolites, such as glucose and lactate; however, their direct incorporation into culture systems is limited by the inactivation of enzymes under culture conditions. In this study, we investigated a vascular MPS with a sensor-compatible design to support future integration of printed enzyme-based biosensors. The device features a stacked open-bottom architecture that enables the integration of biosensors beneath the endothelial layer after monolayer formation, thus minimizing sensor exposure during culture. We validated the formation of an endothelial monolayer on a porous polyurethane membrane with a mortar-like structure and confirmed its compatibility with a model sensor substrate. As a preliminary step toward sensor-based metabolic analysis, we quantified glucose consumption and lactate production during endothelial monolayer formation and upon exposure to Minoxidil and Hydralazine, drugs known to induce vascular injury. These findings demonstrate the feasibility of sensor-compatible vascular MPS and provide foundational data to support the future development of integrated platforms for real-time metabolic monitoring in drug toxicity studies.

One of the most complex human physiological processes to study is pregnancy. Standard animal models, as well as two-dimensional models, lack the complexity and biological relevance required to accurately study such a physiological process. Recent studies have focused on the development of three-dimensional models based on microfluidic systems, designated as placental microphysiological systems (PMPSs). PMPS devices provide a model of the placental barrier through culturing relevant cell types in specific arrangements and media to mimic the in vivo environment of the maternal–fetal circulation. Here, recent developments of PMPS models for embryo uterine implantation, preeclampsia evaluation, and toxicological screening are presented. Studies that use bioprinting techniques are also discussed. Lastly, recent developments in endometrium microphysiological systems are reviewed. All these presented models showed their superiority compared to standard models in recapitulating the biological environment seen in vivo. However, several limitations regarding the types of cells and materials used for these systems were also widely reported. Despite the need for further improvements, PMPS models contribute to a better understanding of the biological mechanisms surrounding pregnancy and the respective pathologies.

The initiation of human pregnancy is marked by the implantation of an embryo into the uterine environment; however, the underlying mechanisms remain largely elusive. To address this knowledge gap, we developed hormone-responsive endometrial organoids (EMO), termed apical-out (AO)–EMO, which emulate the in vivo architecture of endometrial tissue. The AO-EMO comprise an exposed apical epithelium surface, dense stromal cells, and a self-formed endothelial network. When cocultured with human embryonic stem cell–derived blastoids, the three-dimensional feto-maternal assembloid system recapitulates critical implantation stages, including apposition, adhesion, and invasion. Endometrial epithelial cells were subsequently disrupted by syncytial cells, which invade and fuse with endometrial stromal cells. We validated this fusion of syncytiotrophoblasts and stromal cells using human blastocysts. Our model provides a foundation for investigating embryo implantation and feto-maternal interactions, offering valuable insights for advancing reproductive medicine.

Pancreatic islet transplantation presents a promising therapy for individuals suffering from type 1 diabetes. To maintain the function of transplanted islets in vivo, it is imperative to induce angiogenesis. However, the mechanisms underlying angiogenesis triggered by islets remain unclear. In this study, we introduced a microphysiological system to study the angiogenic capacity and dynamics of individual islets. The system, which features an open‐top structure, uniquely facilitates the inoculation of islets and the longitudinal observation of vascular formation in in vivo like microenvironment with islet‐endothelial cell communication. By leveraging our system, we discovered notable islet−islet heterogeneity in the angiogenic capacity. Transcriptomic analysis of the vascularized islets revealed that islets with high angiogenic capacity exhibited upregulation of genes related to insulin secretion and downregulation of genes related to angiogenesis and fibroblasts. In conclusion, our microfluidic approach is effective in characterizing the vascular formation of individual islets and holds great promise for elucidating the angiogenic mechanisms that enhance islet transplantation therapy.

Vasculature-on-a-chip is a microfluidic cell culture device used for modeling vascular functions by culturing endothelial cells. Porous membranes are widely used to create cell culture environments. However, in situ real-time measurements of cellular metabolites in microchannels are challenging. In this study, a novel microfluidic device with a porous membrane electrode was developed for the in situ monitoring of nitric oxide (NO) released by endothelial cells in real time. In this system, a porous Au membrane electrode was placed directly beneath the cells for in situ and real-time measurements of NO, a biomarker of endothelial cells. First, the device was electrochemically characterized to construct a calibration plot for NO. Next, NO released by human umbilical vein endothelial cells under l-arginine stimulation was successfully quantified. Furthermore, the changes in NO release with culture time (in days) using the same sample were successfully recorded by exploiting minimally invasive measurements. This is the first report on the combination of a microfluidic device and porous membrane electrode for the electrochemical analysis of endothelial cells. This device will contribute to the development of organ-on-a-chip technology for real-time in situ cell analyses.

Molecularly imprinted polymers (MIPs) are synthetic polymers with specific binding sites that present high affinity and spatial and chemical complementarities to a targeted analyte. They mimic the molecular recognition seen naturally in the antibody/antigen complementarity. Because of their specificity, MIPs can be included in sensors as a recognition element coupled to a transducer part that converts the interaction of MIP/analyte into a quantifiable signal. Such sensors have important applications in the biomedical field in diagnosis and drug discovery, and are a necessary complement of tissue engineering for analyzing the functionalities of the engineered tissues. Therefore, in this review, we provide an overview of MIP sensors that have been used for the detection of skeletal- and cardiac-muscle-related analytes. We organized this review by targeted analytes in alphabetical order. Thus, after an introduction to the fabrication of MIPs, we highlight different types of MIP sensors with an emphasis on recent works and show their great diversity, their fabrication, their linear range for a given analyte, their limit of detection (LOD), specificity, and reproducibility. We conclude the review with future developments and perspectives.