Removal characteristics of presepsin by operating conditions and hemofilter.

Presepsin, which is used as a biomarker for sepsis, is thought to be removed by dialysis, but the actual removal properties of dialysis are unknown. We investigated the presepsin removal properties of continuous hemodiafiltration using the high concentration of presepsin from human plasma drained by plasma exchange. Each solution in plasma exchange was connected to a continuous hemodiafiltration blood circuit and circulated at 4 conditions. The results show that presepsin was confirmed to be removed more efficiently in hemofiltration than in hemodialysis. In addition, when using a polymethylmethacrylate hemofilter for continuous hemodiafiltration, the lowest presepsin concentration is on the filtrate side, suggesting that the main removal mechanism is adsorption. Since presepsin has a molecular weight of 13,000, its removal efficiency is high by hemofiltration as per principle. In addition, since the main adsorption principle of polymethylmethacrylate hemofilter is hydrophobic bond, presepsin is considered to be adsorbed. Since presepsin is metabolized in the kidney, it is elevated in renal failure. In this paper, we confirmed that presepsin is eliminated by continuous hemodiafiltration not only in the kidney. Depending on the timing of presepsin measurement, there is a risk of missing the diagnosis of sepsis. Kidney function and continuous hemodiafiltration should be checked when measuring presepsin.

Coculture with hiPS-derived intestinal cells enhanced human hepatocyte functions in a pneumatic-pressure-driven two-organ microphysiological system.

Examining intestine-liver interactions is important for achieving the desired physiological drug absorption and metabolism response in in vitro drug tests. Multi-organ microphysiological systems (MPSs) constitute promising tools for evaluating inter-organ interactions in vitro. For coculture on MPSs, normal cells are challenging to use because they require complex maintenance and careful handling. Herein, we demonstrated the potential of coculturing normal cells on MPSs in the evaluation of intestine-liver interactions. To this end, we cocultured human-induced pluripotent stem cell-derived intestinal cells and fresh human hepatocytes which were isolated from PXB mice with medium circulation in a pneumatic-pressure-driven MPS with pipette-friendly liquid-handling options. The cytochrome activity, albumin production, and liver-specific gene expressions in human hepatocytes freshly isolated from a PXB mouse were significantly upregulated via coculture with hiPS-intestinal cells. Our normal cell coculture shows the effects of the interactions between the intestine and liver that may occur in vivo. This study is the first to demonstrate the coculturing of hiPS-intestinal cells and fresh human hepatocytes on an MPS for examining pure inter-organ interactions. Normal-cell coculture using the multi-organ MPS could be pursued to explore unknown physiological mechanisms of inter-organ interactions in vitro and investigate the physiological response of new drugs.