Tubulointerstitial and Vascular Diseases of the Kidney
Section 1 -
Donna J. Lager, M.D. Matthew Lewin, M.D.
Renal diseases can be broadly classified as affecting three compartments: the glomeruli, the tubules
and interstitium and the vasculature. Tubulointerstitial and vascular diseases are the subject of this
The tubulointerstitial compartment comprises approximately 80% of the renal volume. The interstitial
space is made up of both cellular and matrix components. The cells include fibroblast-like cells, and
lipid-rich interstitial cells in the inner medulla; and monocytes and dendritic antigen-presenting cells
found primarily in the cortex. The interstitial compartment provides structural support for individual
nephrons, is involved in solute transport and is the site of production of hormones and cytokines.
Diseases affecting the tubulointerstitial compartment may result from primary injury to this
compartment, or may be secondary to injury to the other compartments. Changes in the tubulointerstitial
compartment are a better predictor of the severity of renal dysfunction and long-term outcome than
changes in other compartments.
The renal artery which enters the kidney at the renal hilum, carries about one-fifth of the cardiac
output. The renal artery bifurcates several times after entering the kidney and branches into arcuate
arteries which run in an arch-like fashion along the corticomedullary junction. The arcuate arteries
give rise to the interlobular arteries which run to the surface of the kidney and from which arise the
afferent arterioles supplying the glomeruli. As the blood leaves the glomerulus, the capillaries
coalesce into the efferent arteriole, which almost immediately bifurcates again to form the peritubular
capillary network. The peritubular capillaries coalesce to form venules and eventually the renal vein.