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The Biphasic Nature of Renal Functional Recovery Following Relief of Chronic Obstructive Uropathy
RENAL PHYSIOLOGY, RENAL FAILURE AND HYPERTENSION
Agents or conditions injurious to glomerular epithelium tend to cause glomerular sclerosis. Agents or conditions that induce short-term or long-term activation of mesangial cells may lead to glomerular sclerosis. Indeed, a contribution of the healthy epithelium may be to serve as a tonic inhibitor of the intraglomerular processes arising from mesangial-cell activation. Longterm activation of the mesangium is associated with the proliferation and infiltration of cells and with the expansion of the mesangial matrix-the antecedents of sclerosis. We anticipate that different diseases associated with glomerular sclerosis will be found to depend to varying extents on these 2 potential mechanisms of sclerosis. Beyond a certain threshold of glomerular injury, glomerular diseases share an additional factor; the capacity of intrinsic cells and infiltrating cells to alter the microenvironment of the glomerulus so that sclerosis progresses inexorably long after the disappearance of the initiating insult. Several potential risk factors may contribute to the progression of chronic renal disease, including systemic hypertension, proteinuria, hyperlipidemia, high protein intake and probably conditions that lead to glomerular hypertrophy. Interventions designed to minimize the potential contribution of these factors to the progression of renal insufficiency may halt or slow the loss of function of the kidney. Clinical trials designed to examine the effects of these factors on the progressive course of renal insufficiency will help to establish their role and relative importance in humans. Editorial Comment: This is an excellent review of the complex interactions that may be operative in the progression of nephron injury. E. Darracott Vaughan, M.D. The Biphasic Nature of Renal Functional Recovery Following Relief of Chronic Obstructive Uropath.y
D. A. JONES, N. J. R. GEORGE, P. H. O'REILLY AND R. J. BARNARD, Departments of Urology, University Hospital of South Manchester and Stepping Hill Hospital, Stockport, England Brit. J. Urol., 61: 192-197, 1988 Twenty-one patients with chronic obstructive uropathy due to high pressure chronic retention of urine underwent renal functional assessment both during the period of obstruction and repeatedly up to 3 months following its relief. Glomerular filtration rate (GFR) was determined using clearance of 99 mTcDTP A and iohexol. Creatinine, water, urea and electrolyte excretion was assessed from timed urine collections. Excretion of water, urea and electrolyte was normal during obstruction but increased dramatically immediately following relief (e.g. sodium 110 to 234 mmol/24 h). Values returned to normal by 2 weeks (sodium excretion 148 mmol/24 h). No further significant changes occurred up to 3 months. Mean 99 mTc-DTP A and iohexol clearances during obstruction were 59.0 and 50.5 ml/min respectively. Following relief of obstruction, no significant improvement occurred at 2 weeks but did at 3 months (mean= 68.4 and 55.7 ml/min). Mean creatinine clearance during obstruction was 32.5 ml/min. This improved 2 days following relief to 46 ml/min. No further improvement was seen until 3 months (mean= 57.3 ml/min). It was concluded that recovery of renal function from obstructive injury occurs in two phases, an early tubular phase lasting up to 2 weeks and a later, predominantly glomerular
681
phase, between 2 weeks and 3 months. There is some disparity between creatinine clearance and more accurate measurements of GFR which may be explained by tubular excretion of creatinine in the early phase of recovery. Editorial Comment: The autho:rs continue their excellent series of studies of patients with what they term high. pressure chronic obstruction. The inte:rested reader also should :review their previous articles. E. Darracott Vaughan, M.D. Chloride Transport in the Proximal Renal Tubule
L. SCHILD, G. GIEBISCH AND R. GREEN, Department of Physiology, Yale University School of Medicine, New Haven, Connecticut and Department of Physiological Sciences, University of Manchester, Manchester, England Ann. Rev. Physiol., 50: 97-110, 1988 Editorial Comment: Most of us were taught that sodium was the prime mover in transport of sodium chloride in the proximal tubule and loop of Henle. Evidence is mounting that chloride transport is not solely passive at these sites. E. Dai!."racott Vaughan, M.D. Renal Syndromes in the Acquired Immunodeficiency Syndrome (AIDS): Lessons Learned Frnm Analysis Over 5 Years T. K. S. RAO AND E. A. FRIEDMAN, Department of Medi-
cine, Health Science Center at Brooklyn, State University of New York, Brooklyn, New York Artif. Organs, 12: 206-209, 1988 Renal syndromes associated with the Acquired immunodeficiency syndrome include: potentially reversible acute renal failure, AIDS associated nephropathy which leads to end stage renal disease, and AIDS developing in patients who are being treated by maintenance hemodialysis. The longitudinal study of 95 patients with AIDS and various forms of renal syndrome at two urban institutions indicates that both acute and chronic renal failure is increasing yearly. While some patients with acute renal failure recover renal function and survive for prolonged period, the mortality of dialyzed patients with irreversible renal failure continues to be unsatisfactory. There is a great need for collecting data from high risk areas to analyze the results of maintenance dialysis therapy in patients with AIDS, to assess the economic impact of uremia therapy, and for long-term planning of available resources. Editorial Comment: The n.ephrnpathy of the acquired immunodeficiency syndrome appears to be real and its impact on dialysis units currently is undetermined, E. Darracott Vaughan, M.D, Comparison of Magnetic Resonance Imaging and Radionuclide Imaging in the Evaluation of Renal Transplant Failure
M.
D. E. TANASESCU, A. D. WAXMAN III, Departments of Radiology and Nuclear Medicine, Cedars-Sinai Medical Center, Los Angeles, California S. GOLDSMITH, AND J. V. CRUES,
Clin. Nucl. Med., 13: 250-257, 1988
Agents or conditions injurious to glomerular epithelium tend to cause glomerular sclerosis. Agents or conditions that induce short-term or long-term activation of mesangial cells may lead to glomerular sclerosis. Indeed, a contribution of the healthy epithelium may be to serve as a tonic inhibitor of the intraglomerular processes arising from mesangial-cell activation. Longterm activation of the mesangium is associated with the proliferation and infiltration of cells and with the expansion of the mesangial matrix-the antecedents of sclerosis. We anticipate that different diseases associated with glomerular sclerosis will be found to depend to varying extents on these 2 potential mechanisms of sclerosis. Beyond a certain threshold of glomerular injury, glomerular diseases share an additional factor; the capacity of intrinsic cells and infiltrating cells to alter the microenvironment of the glomerulus so that sclerosis progresses inexorably long after the disappearance of the initiating insult. Several potential risk factors may contribute to the progression of chronic renal disease, including systemic hypertension, proteinuria, hyperlipidemia, high protein intake and probably conditions that lead to glomerular hypertrophy. Interventions designed to minimize the potential contribution of these factors to the progression of renal insufficiency may halt or slow the loss of function of the kidney. Clinical trials designed to examine the effects of these factors on the progressive course of renal insufficiency will help to establish their role and relative importance in humans. Editorial Comment: This is an excellent review of the complex interactions that may be operative in the progression of nephron injury. E. Darracott Vaughan, M.D. The Biphasic Nature of Renal Functional Recovery Following Relief of Chronic Obstructive Uropath.y
D. A. JONES, N. J. R. GEORGE, P. H. O'REILLY AND R. J. BARNARD, Departments of Urology, University Hospital of South Manchester and Stepping Hill Hospital, Stockport, England Brit. J. Urol., 61: 192-197, 1988 Twenty-one patients with chronic obstructive uropathy due to high pressure chronic retention of urine underwent renal functional assessment both during the period of obstruction and repeatedly up to 3 months following its relief. Glomerular filtration rate (GFR) was determined using clearance of 99 mTcDTP A and iohexol. Creatinine, water, urea and electrolyte excretion was assessed from timed urine collections. Excretion of water, urea and electrolyte was normal during obstruction but increased dramatically immediately following relief (e.g. sodium 110 to 234 mmol/24 h). Values returned to normal by 2 weeks (sodium excretion 148 mmol/24 h). No further significant changes occurred up to 3 months. Mean 99 mTc-DTP A and iohexol clearances during obstruction were 59.0 and 50.5 ml/min respectively. Following relief of obstruction, no significant improvement occurred at 2 weeks but did at 3 months (mean= 68.4 and 55.7 ml/min). Mean creatinine clearance during obstruction was 32.5 ml/min. This improved 2 days following relief to 46 ml/min. No further improvement was seen until 3 months (mean= 57.3 ml/min). It was concluded that recovery of renal function from obstructive injury occurs in two phases, an early tubular phase lasting up to 2 weeks and a later, predominantly glomerular
681
phase, between 2 weeks and 3 months. There is some disparity between creatinine clearance and more accurate measurements of GFR which may be explained by tubular excretion of creatinine in the early phase of recovery. Editorial Comment: The autho:rs continue their excellent series of studies of patients with what they term high. pressure chronic obstruction. The inte:rested reader also should :review their previous articles. E. Darracott Vaughan, M.D. Chloride Transport in the Proximal Renal Tubule
L. SCHILD, G. GIEBISCH AND R. GREEN, Department of Physiology, Yale University School of Medicine, New Haven, Connecticut and Department of Physiological Sciences, University of Manchester, Manchester, England Ann. Rev. Physiol., 50: 97-110, 1988 Editorial Comment: Most of us were taught that sodium was the prime mover in transport of sodium chloride in the proximal tubule and loop of Henle. Evidence is mounting that chloride transport is not solely passive at these sites. E. Dai!."racott Vaughan, M.D. Renal Syndromes in the Acquired Immunodeficiency Syndrome (AIDS): Lessons Learned Frnm Analysis Over 5 Years T. K. S. RAO AND E. A. FRIEDMAN, Department of Medi-
cine, Health Science Center at Brooklyn, State University of New York, Brooklyn, New York Artif. Organs, 12: 206-209, 1988 Renal syndromes associated with the Acquired immunodeficiency syndrome include: potentially reversible acute renal failure, AIDS associated nephropathy which leads to end stage renal disease, and AIDS developing in patients who are being treated by maintenance hemodialysis. The longitudinal study of 95 patients with AIDS and various forms of renal syndrome at two urban institutions indicates that both acute and chronic renal failure is increasing yearly. While some patients with acute renal failure recover renal function and survive for prolonged period, the mortality of dialyzed patients with irreversible renal failure continues to be unsatisfactory. There is a great need for collecting data from high risk areas to analyze the results of maintenance dialysis therapy in patients with AIDS, to assess the economic impact of uremia therapy, and for long-term planning of available resources. Editorial Comment: The n.ephrnpathy of the acquired immunodeficiency syndrome appears to be real and its impact on dialysis units currently is undetermined, E. Darracott Vaughan, M.D, Comparison of Magnetic Resonance Imaging and Radionuclide Imaging in the Evaluation of Renal Transplant Failure
M.
D. E. TANASESCU, A. D. WAXMAN III, Departments of Radiology and Nuclear Medicine, Cedars-Sinai Medical Center, Los Angeles, California S. GOLDSMITH, AND J. V. CRUES,
Clin. Nucl. Med., 13: 250-257, 1988