Ex Vivo
Experiments performed on living cells, tissues, or organs removed from an organism but maintained in conditions mimicking the living environment. Ex vivo studies bridge the gap between in vitro and in vivo research, providing more physiologically relevant data than cell culture while allowing direct manipulation.
Technical Context
Ex vivo preparations maintain tissue architecture, cell-cell interactions, and local microenvironment while allowing direct manipulation and observation. Common ex vivo models include: isolated organ preparations (Langendorff perfused heart for cardiac effects, isolated perfused kidney for renal effects), tissue slices (brain slices for electrophysiology, precision-cut liver slices for metabolism), skin explants (Franz diffusion cells for transdermal peptide delivery studies), and isolated blood vessel rings (isometric tension recording for vasoactive effects). Ex vivo studies of peptide effects on isolated human tissue (obtained from surgical specimens with consent) provide the most directly translatable data. The limitation is tissue viability — most ex vivo preparations remain functional for hours to days, restricting study duration.