摘出した臓器に人工的に液体（主に培養液や血液代替液）を循環させ、酸素や栄養を供給しながら機能を維持する技術・プロセスである。灌流液は臓器の血管系を通って流れ、老廃物の除去や恒常性の維持も担う。ex vivo perfusion（体外灌流）の一形態として、臓器単位での機能評価・保存・再生に用いられる。

This term refers to the phenomenon in which multiple cells exchange information and signals, either directly or indirectly. It is essential for all physiological and pathological processes, including development, tissue formation, maintenance of homeostasis, immune responses, and disease progression. Cells influence one another through physical contact, secreted factors (such as cytokines and growth factors), and the extracellular matrix.