Acute Renal Failure in Man: New Aspects Concerning Pathogenesis

Abstract

The morphometric investigation of the proximal and distal tubules, the cortical interstitium, the inter-tubular capillaries, the renal corpuscles and the juxtaglomerular apparatuses (JGAs) in 56 cases in the oligoanuric, polyuric, and normuric phases of human acute renal failure (ARF), 6 cases of myeloma kidney with clinically confirmed ARF and 21 control kidneys revealed the following: (1) The main pathological change in human ARF is swelling of the epithelial cells of the proximal and distal tubules. Necrosis of these cells was observed in some cases but usually only as single cell necroses. (2) The interstitium of the cortex and of the outer stripe of the outer medulla is significantly widened in most cases of ARF. (3) In proximal tubules proximal to occluding casts (which were observed only in the plasmacytoma cases), the lumina are not widened but are narrower than normal, and the cross-sectional area of the epithelium is not greater but smaller than normal. (4) The JGAs were significantly larger in kidneys in the oligoanuric phase of ARF (with 1 exception) than in normal kidneys. In the normuric and polyuric phases they were slightly (not significantly) smaller than normal. In myeloma kidneys with occluding casts and/or diffuse interstitial fibrosis, the JGAs were significantly smaller than normal. From these findings it is concluded that: (1) The fall in glomerular filtration rate (GFR) in the postshock phase of ARF is not caused by nonselective back-diffusion of the primary urine through necrotic tubules or by compression of the lumina of the proximal and distal tubules by interstitial edema. A fall in GFR associated with occluding casts in the distal tubules is found only in the myeloma kidney and does not lead to widening of the proximal tubules but to tubular atrophy and narrowing of the lumen. (2) The casts seen in the lumina of the ascending limb of Henle’s loop in some cases of ARF, which consist of hemoglobin, Tamm-Horsfall protein or desquamated blebs, do not occlude the lumen, since they are not associated with atrophy or luminal dilatation of the proximal tubules. (3) The JGAs with their secretory product renin-angiotensin II, together with adenosine, which is released in kidneys with ischemic or toxic damage, play a critical role in the pathogenesis of ARF. (4) In myeloma kidneys with ARF, in which the JGAs are markedly atrophic, the potentiated effect of adenosine that has been observed with a chronic absence of urine flow probably leads to a progressive, irreversible drop in GFR associated with tubular atrophy.

Non-Invasive Magnetic Resonance Imaging in Rats for Prediction of the Fate of Grafted Kidneys from Cardiac Death Donors

“…Because increased and decreased ADC represent interstitial and cellular edema, respectively [17], the changes in ADC values identified by diffusion MRI suggest that there is interstitial edema in the IS of CD2h kidney grafts. This is consistent with the observation that interstitial edema is a common finding in human biopsy specimens of acute kidney injury [23]. In addition, tubular cellular edema in the OS, which decreased ADC in this region suggests, may inhibit erythrocytes from coming out of the medulla back up to the cortex, resulting in a vicious cycle of graft dysfunction [24] (Figure 8).…”

Measuring Single-Kidney Glomerular Filtration Rate on Single-Detector Helical CT Using a Two-Point Patlak Plot Technique in Patients with Increased Interstitial Space

“…The kidney volume we found in the patients in our study was much larger than one would expect in individuals with healthy kidneys, indicating swelling of the kidneys or, speaking pathophysiologically, an increased interstitial space. In healthy kidneys, the interstitial space in the renal cortex as measured by histopathologic techniques is 8.4% and that of the outer stripe of the outer medulla is 17.6% [13]. In the same study, interstitial space increased in patients with acute renal failure by approximately 10% in the renal cortex and by a similar amount in the outer stripe of the outer medulla.…”

Morphology of interstitial cells in the healthy kidney

“…A renaissance of interest in the renal tubulointerstitial compartment has occurred in recent years due to the growing awareness that the peritubular interstitium, even though its overall fractional volume is small (Lemley and Kriz 1991), plays a pivotal role in renal pathologies and constitutes a major factor determining the issue of renal failures (Bohle et al 1990;Kuncio et al 1991;Cameron 1992;Fine et al 1995). The interest directed towards the interstitium is in striking contrast to the relatively slight knowledge about the morphological aspects of renal tubulointerstitium in healthy kidneys in vivo.…”