Subcellular fractionation of human intestinal mucosa by large-scale zonal centrifugation. Separation of the organelles in diseased ileum of a patient with Crohn's disease.

The subcellular organelles in diseased ileal mucosa of a patient with Crohn's disease have been separated by rate zonal density gradient centrifugation. Mucosal scrapings were obtained from a surgical specimen of diseased intestine and the cells disrupted by extrusion under controlled pressure. The homogenized cells were then centrifuged to prepare a cell extract and the extract fractionated in a single-step procedure by zonal centrifugation on a continuous sucrose gradient. The subcellular organelles (brush borders, basal-lateral membranes, lysosomes, mitochondria and endoplasmic reticulum) were located in the density gradient by assay of marker enzymes and their overall distribution compared with the distribution of organelles from a normal tissue. The centrifugal properties of individual organelles in the diseased tissue were largely unaffected but the lysosomes were more fragile than in the normal tissue. Since the fractionation technique used is on a large scale, each fraction of interest can be further analyzed for a variety of compounds. Therefore, the subcellular pathology and pathophysiology in this and other cases of Crohn's disease may eventually be studied and discussed in other than morphological and descriptive terms.