Chemical and physiological properties of polysucrose, a new marker of intestinal permeability to macromolecules.

To measure intestinal absorption of macromolecules we have developed a new technique employing synthetic polysucrose polymers as probe molecules. Polysucrose (PS) is water-soluble, nontoxic, resistant to intestinal enzymes, spherical and can be produced with a molecular weight distribution that relates to the size of many normal food proteins. Normally, a very small fraction of large molecules passes the exclusion barrier of the healthy intestine. Thus, quantification of resorbed macromolecules requires assays of high sensitivity. For detection of PS in various biological fluids, micro-ELISAs have been established. PS with a mean molecular weight of 14,700 daltons (PS 15,000) is rapidly excreted into the urine. Twenty-one healthy volunteers who orally ingested 1 g of this preparation showed a 12-hour urine excretion of 0.018% (interquartile range 0.014-0.022).