Biomaterial Database

Structural determinants of glomerular hydraulic permeability. 1994

M C Drumond, and W M Deen

Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139.

To elucidate which structures determine the resistance to water movement, we used a computational fluid dynamics approach to determine velocity and pressure fields within the glomerular capillary wall. The model included representations of the endothelial fenestrae, basement membrane, and epithelial filtration slits with slit diaphragms. The input data included dimensions of the various structures from previous electron microscopy studies, as well as the hydraulic permeability recently measured for isolated films of glomerular basement membrane in vitro. The hydraulic resistance of the endothelium was predicted to be small, whereas the basement membrane and filtration slits were each found to contribute roughly one-half of the total hydraulic resistance of the capillary wall. It was calculated that, for a given filtrate flux, the pressure drop within basement membrane in vivo is roughly twice that of "bare" or isolated basement membrane, because of the small fraction of basement membrane area exposed. The dominant resistance in the filtration slit was found to be the slit diaphragm. Predicted values for the overall hydraulic permeability of the capillary wall were within the experimental range derived from micropuncture measurements in normal rats. The model should be a useful tool for analyzing the effects of various structural changes on glomerular hydraulic permeability. This is illustrated by applying the model to recent physiological and morphometric data in nephrotic rats.

UI	MeSH Term	Description	Entries
D007678	Kidney Glomerulus	A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.	Glomerulus, Kidney
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D002196	Capillaries	The minute vessels that connect arterioles and venules.	Capillary Beds,Sinusoidal Beds,Sinusoids,Bed, Sinusoidal,Beds, Sinusoidal,Capillary,Capillary Bed,Sinusoid,Sinusoidal Bed
D002199	Capillary Permeability	The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.	Microvascular Permeability,Permeability, Capillary,Permeability, Microvascular,Vascular Permeability,Capillary Permeabilities,Microvascular Permeabilities,Permeabilities, Capillary,Permeabilities, Microvascular,Permeabilities, Vascular,Permeability, Vascular,Vascular Permeabilities
D004730	Endothelium, Vascular	Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.	Capillary Endothelium,Vascular Endothelium,Capillary Endotheliums,Endothelium, Capillary,Endotheliums, Capillary,Endotheliums, Vascular,Vascular Endotheliums
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001485	Basement Membrane	A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.	Basal Lamina,Basement Lamina,Lamina Densa,Lamina Lucida,Lamina Reticularis,Basement Membranes,Densas, Lamina,Lamina, Basal,Lamina, Basement,Lucida, Lamina,Membrane, Basement,Membranes, Basement,Reticularis, Lamina