A mathematical and conceptual model of water and solute transport for whole hamster pancreatic islets has been developed and experimentally validated incorporating fundamental biophysical data from previous studies on individual hamster islet cells while retaining whole-islet structural information. It describes coupled transport of water and solutes through the islet by three methods: intracellularly, intercellularly, and in combination. Here we couple a transmembrane flux model with an interstitial mass transfer model and show that the only significant undetermined variable is that of the cellular surface area which is in contact with the intercellularly transported solutes, A_is. The model was validated and A_is determined using a 3 × 3 factorial experimental design blocked for experimental day. Whole islet physical experiments were compared with model predictions at three temperatures, three perfusing solutions, and three islet size groups. A mean of 4.4 islets were compared at each of the 27 experimental conditions and found to correlate with a coefficient of determination of 0.87 ± 0.06 (mean ± S.D.). Only the treatment variable of perfusing solution was found to be significant (p<0.05). Extensions to ovarian follicles and other concentric tissue structures may be made.
Citation: Biophysical Journal
Pub Type: Journals
perfusion, diffusion, cryobiology, multicellular mathematical modeling, solute transport, water transport