Development of albumin monitoring system with hepatic hypoxia-on-a-chip

Lower bilirubin levels in newborns with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia may indicate suppressed heme oxygenase activity

Despite having risk factors for hyperbilirubinemia, newborns with hypoxic ischemic encephalopathy (HIE) often exhibit unexpectedly low bilirubin levels, potentially due to reduced heme oxygenase (HO) activity. This study aims to evaluate bilirubin dynamics and HO activity in moderate to severe HIE newborns undergoing therapeutic hypothermia (TH) within a Japanese cohort. In this matched case-control study, newborns with HIE who underwent TH (case group) and control newborns without HIE (control group) treated at our perinatal center between 2019 and 2024 were retrospectively studied. Control newborns, admitted for respiratory distress or other conditions, were matched by gestational age, birth weight, sex, and birth date. Clinical data, including the total serum bilirubin (TsB), transcutaneous bilirubin (TcB), and carboxyhemoglobin (COHb) levels (an indicator of HO activity) were collected and analyzed during the first week of life. A total of 32 cases were analyzed in both the case and control groups. The case group had significantly lower TsB and TcB levels over time. COHb levels were comparable between the groups until 96 h of life but became significantly higher in the case group thereafter.

CONCLUSION

 In this Japanese cohort, TsB and TcB levels were consistently lower in HIE newborns undergoing TH during the first week of life. COHb levels were initially comparable but increased later in the case group. These findings suggest that reduced HO activity may contribute to suppressed heme degradation in moderate to severe HIE cases receiving TH.

WHAT IS KNOWN

• Newborns with hypoxic ischemic encephalopathy (HIE) often exhibit lower bilirubin levels than expected, despite risk factors for hyperbilirubinemia.

WHAT IS NEW

• This study indicates that reduced heme oxygenase activity may contribute to the lower bilirubin levels observed in HIE newborns undergoing therapeutic hypothermia.

Development of an electrochemical biosensor for non-invasive cholesterol monitoring via microneedle-based interstitial fluid extraction

In this study, we present the development of an innovative electrochemical biosensor integrated into a microneedle-based system for non-invasive and sensitive quantification of cholesterol levels in interstitial fluid (ISF). The biosensor employs a graphene-based electrode with a polyelectrolyte interlayer to immobilize cholesterol oxidase (ChOx), enabling selective cholesterol detection. Graphene oxide is electrochemically reduced to form a conductive layer, and PANI is chosen as the optimal polyelectrolyte for ChOx immobilization. The biosensor's performance is thoroughly evaluated, demonstrating excellent sensitivity, stability, and selectivity. Furthermore, the biosensor is successfully applied to skin-mimicking agarose gel and porcine skin, showcasing its potential for real-world interstitial fluid extraction and cholesterol monitoring. The integrated microneedle-based system offers a promising approach for non-invasive monitoring of cholesterol levels, with implications for personalized healthcare diagnostics.

Advanced Liver-on-a-Chip Model for Evaluating Drug Metabolism and Hepatotoxicity

The liver has many important functions, including the biotransformation of drugs and detoxification of the human organism. As such, it is also exposed to many harmful substances, which leads to disorders and diseases such as cirrhosis. For these reasons, it seems important to consider liver metabolism and the direct effects on the liver when evaluating the efficacy of new drugs. Accordingly, we have developed an advanced in vitro liver model using an organ-on-a-chip approach that replicates many of the morphological and functional features of the liver in vivo. The model we created can metabolize drugs, which we demonstrated using two widely used anticancer drugs, 5-fluorouracil (5FU) and capecitabine (CAP). In addition, to the best of our knowledge, we are the first who evaluate the direct effects of these drugs not only on the viability of liver model-building cells but on their functions, such as cytochrome P450 activity and albumin production. Our study brings new hope to properly evaluating drug efficacy at the in vitro level.

Fibrosis-on-Chip: A Guide to Recapitulate the Essential Features of Fibrotic Disease

Fibrosis, which is primarily marked by excessive extracellular matrix (ECM) deposition, is a pathophysiological process associated with many disorders, which ultimately leads to organ dysfunction and poor patient outcomes. Despite the high prevalence of fibrosis, currently there exist few therapeutic options, and importantly, there is a paucity of in vitro models to accurately study fibrosis. This review discusses the multifaceted nature of fibrosis from the viewpoint of developing organ-on-chip (OoC) disease models, focusing on five key features: the ECM component, inflammation, mechanical cues, hypoxia, and vascularization. The potential of OoC technology is explored for better modeling these features in the context of studying fibrotic diseases and the interplay between various key features is emphasized. This paper reviews how organ-specific fibrotic diseases are modeled in OoC platforms, which elements are included in these existing models, and the avenues for novel research directions are highlighted. Finally, this review concludes with a perspective on how to address the current gap with respect to the inclusion of multiple features to yield more sophisticated and relevant models of fibrotic diseases in an OoC format.

Construction of in vitro liver-on-a-chip models and application progress

The liver is the largest internal organ of the human body. It has a complex structure and function and plays a vital role in drug metabolism. In recent decades, extensive research has aimed to develop in vitro models that can simulate liver function to demonstrate changes in the physiological and pathological environment of the liver. Animal models and in vitro cell models are common, but the data obtained from animal models lack relevance when applied to humans, while cell models have limited predictive ability for metabolism and toxicity in humans. Recent advancements in tissue engineering, biomaterials, chip technology, and 3D bioprinting have provided opportunities for further research in in vitro models. Among them, liver-on-a-Chip (LOC) technology has made significant achievements in reproducing the in vivo behavior, physiological microenvironment, and metabolism of cells and organs. In this review, we discuss the development of LOC and its research progress in liver diseases, hepatotoxicity tests, and drug screening, as well as chip combinations. First, we review the structure and the physiological function of the liver. Then, we introduce the LOC technology, including general concepts, preparation materials, and methods. Finally, we review the application of LOC in disease modeling, hepatotoxicity tests, drug screening, and chip combinations, as well as the future challenges and directions of LOC.