Effects of enalapril on adriamycin-induced nephrosis

Reduced progression of adriamycin nephropathy in spontaneously hypertensive rats treated by losartan

BACKGROUND

The aim of the study was to investigate the antihypertensive effects of angiotensin II type-1 receptor blocker, losartan, and its potential in slowing down renal disease progression in spontaneously hypertensive rats (SHR) with adriamycin (ADR) nephropathy.

METHODS

Six-month-old female SHR were randomly selected in six groups. Two control groups (SH(6), SH(12)) received vehicle. Groups ADR(6), ADR+LOS(6) and ADR(12), and ADR+LOS(12) received ADR (2 mg/kg/b.w. i.v.) twice in a 3-week interval. Group ADR+LOS(6) received losartan (10 mg/kg/b.w./day by gavages) for 6 weeks and group ADR+LOS(12) for 12 weeks after second injection of ADR. Animals were killed after 6 or 12 weeks, respectively. Haemodynamic measurements were performed on anaesthetized animals, blood and urine samples were taken for biochemical analysis and the left kidney was processed for morphological studies.

RESULTS

Short-term losartan treatment, besides antihypertensive effect, improved glomerular filtration rate and ameliorated glomerulosclerosis resulting in decreased proteinuria. Prolonged treatment with losartan showed further reduction of glomerulosclerosis associated with reduced progression of tubular atrophy and interstitial fibrosis, thus preventing heavy proteinuria and chronic renal failure. Losartan reduced uraemia and increased urea clearance in advanced ADR nephropathy in SHR. Histological examination showed that losartan could prevent tubular atrophy, interstitial infiltration and fibrosis in ADR nephropathy.

CONCLUSION

Losartan reduces the rate of progression of ADR-induced focal segmental glomerulosclerosis to end-stage renal disease in SHR.

Clinical characteristics of normotensive renal transplant recipients with microalbuminuria and effects of angiotensin II type I receptor antagonist on urinary albumin excretion

AIM

Microalbuminuria is typically observed in renal transplant recipients with systemic hypertension. The effects of angiotensin II type 1 receptor antagonist (losartan) on the hypertensive recipients have been evaluated. However, the clinical background of normotensive recipients with microalbuminuria and the effect of losartan administration in those subjects have not been clarified. One of the two purposes for the present study was to investigate the clinical characteristics of normotensive recipients with microalbuminuria. The other was to evaluate the effect of losartan on urinary excretion of albumin in these patients.

METHODS

The clinical data and the change of the single kidney glomerular filtration rate (GFR) for the graft by radionuclide study were assessed in 13 normotensive recipients with microalbuminuria. These were compared with the data of 13 normotensive patients without microalbuminuria. The 13 recipients with microalbuminuria were treated with losartan for one year and urine excretion of albumin, N-acetyl-beta-D-glucosaminidase (NAG) and serum creatinine (S-Cr) levels were measured.

RESULTS

The GFR of the grafts from donors to recipients significantly increased (30.9 to 55.2 mL/min) in microalbuminuric recipients, but did not significantly increase in the non-microalbuminuric recipients. Decreases of the urinary excretion rate of albumin (351 +/- 261 at baseline to 158 +/- 14 mg/gCr at 12 months), NAG (13 +/- 5 to 10 +/- 3 IU/gCr) and S-Cr (1.7 +/- 0.6 to 1.5 +/- 0.4 mg/DL) were observed in the microalbuminuric recipients with losartan administration.

CONCLUSIONS

The present study suggests that an increased single kidney GFR of the graft from the donor in situ to the recipient might be a cause of microalbuminuria in normotensive recipients. The one-year effects of losartan were observed in terms of the decrease in urinary excretion of albumin, NAG and S-Cr levels.

Suppression of glomerulosclerosis by adenovirus-mediated IL-10 expression in the kidney

Glomerulosclerosis is a common morphologic result seen in almost all progressed renal diseases, and is the characteristic change in focal segmental glomerulosclerosis (FSGS). The most convincing hypothesis for glomerulosclerosis is cytokine-mediated injury by infiltrating immune cells in the glomerulus and tubulointerstitial area. This study investigated whether the anti-inflammatory effect of interleukin-10 (IL-10) when expressed by a recombinant adenoviral vector can prevent the onset of glomerulosclerosis in FGS/Kist mice (an animal model with naturally occurring renal failure initiated by FSGS). Each group of mice received recombinant adenoviruses encoding human IL-10 (Ad:hIL-10) by intraparenchymal injection at 6 weeks and were examined for cytokine expression, glomerular sclerotic index, and proteinuria. After injection of Ad:hIL-10 to the kidney, IL-10 expression was found to last over 20 days. Mice treated with Ad:hIL-10 were shown to have a significant reduction in the glomerular sclerotic index at 10 weeks when compared to control groups. The level of proteinuria in Ad:hIL-10-treated mice was also significantly reduced. About 50% of the urine samples of naive and Ad:LacZ-treated groups had severe levels of proteinuria. By contrast, at 10 weeks the group treated with Ad:hIL-10 had lower levels of proteinuria and transforming growth factor-beta1 (TGF-beta1) expression. These results demonstrate that IL-10 effectively prevents the development of glomerulosclerosis in FGS/Kist mice, and IL-10 gene therapy may be of use for the treatment of renal failure.

Angiotensin-converting enzyme inhibitor therapy for ventricular dysfunction in infants, children and adolescents: a review

Angiotensin-converting enzyme (ACE) inhibitors have become an important part of the pharmacologic armamentarium in the battle against treatment of ventricular dysfunction. There have been a number of large controlled, randomized trials in adults with both asymptomatic and symptomatic ventricular dysfunction, which confirm the safety and efficacy of this category of drugs for the treatment of this potentially lethal condition. ACE inhibitors may be used to treat infants, children and adolescents with asymptomatic and symptomatic ventricular dysfunction as well. The data supporting their use in children is less complete than that concerning the treatment of adults. We review here the various causes of ventricular dysfunction and congestive heart failure (CHF) in infants, children, and adolescents; the data available regarding treatment of these conditions with ACE inhibitors, and the safety and efficacy of these drugs for the various conditions. The pharmacokinetics and proposed mechanisms of action of ACE inhibitors in children are reviewed, as are speculated long-term results of ACE inhibitor use in cohorts of growing children. Recommendations are made for future studies.

Sodium bicarbonate treatment reduces renal injury, renal production of transforming growth factor-beta, and urinary transforming growth factor-beta excretion in rats with doxorubicin-induced nephropathy

The aim of this study is to investigate the effect of sodium bicarbonate on doxorubicin-injected rats. Thirty female Wistar rats were injected with doxorubicin (3.5 mg/kg of body weight, intravenously) and 30 rats with 0.15 mol/L of sodium chloride solution (group C). Fifteen days later, we replaced the drinking water with a 0.15-mol/L sodium bicarbonate solution for 10 of the animals injected with doxorubicin (group AD-B). Three months after the beginning of treatment, urine samples were collected to quantify albumin, creatinine, and transforming growth factor-beta (TGF-beta). The rats were killed, and the kidneys were removed for histological, morphometric, immunohistochemical, and RNA studies. All doxorubicin-injected animals showed structural renal changes. However, these alterations were less intense in rats treated with doxorubicin plus sodium bicarbonate (P < 0.05). The percentage of glomerulosclerosis was 0.11% +/- 0.08% in group C, 14.7% +/- 12.8% in group AD (rats treated with doxorubicin only), and 4.38% +/- 1.9% in group AD-B, and the percentage of tubulointerstitial damage was 0. 01% +/- 0.03% in group C, 54.6% +/- 20.3% in group AD, and 16.6% +/- 10.3% in group AD-B. The immunostaining for TGF-beta in the renal cortex and glomeruli was more intense in the animals injected with doxorubicin only. A greater renal cortical TGF-beta messenger RNA content was observed in the animals injected with only doxorubicin that did not receive sodium bicarbonate (P < 0.05). These animals also presented a greater rate of urinary TGF-beta excretion reported as picograms of TGF-beta per milligram of urinary creatinine (P < 0.05), which was 202 +/- 11 pg/mg in group C, 1, 103 +/- 580 pg/mg in group AD, and 299 +/- 128 pg/mg in group AD-B. However, albuminuria was more intense in the sodium bicarbonate-treated animals (P < 0.05). The animals from group AD also showed higher immunostaining scores for vimentin and albumin in tubule cells (P < 0.05). In conclusion, treatment with sodium bicarbonate reduces structural renal damage, albumin reabsorption, and renal TGF-beta production in rats with doxorubicin-induced nephropathy.

Focal segmental glomerulosclerosis in children with acute lymphocytic leukemia: case reports and review of literature

PURPOSE

To report the occurrence of focal segmental glomerulosclerosis (FSGS) in children with acute lymphocytic leukemia (ALL), discuss pathogenesis and problems in management.

PATIENTS AND METHODS

Progressive renal dysfunction developed in two adolescent black girls with high-risk ALL who underwent renal biopsies that were consistent with FSGS. In both patients, no known etiologic factors, such as systemic lupus erythematosus, poststreptococcal glomerulonephritis, sickle cell anemia, or acquired immunodeficiency syndrome, were evident. FSGS induced by Adriamycin (Pharmacia & Upjohn, Columbus, OH) has been observed experimentally in rats. The patients had received anthracyclines and methotrexate, a known nephrotoxic chemotherapeutic agent.

RESULTS

One patient progressed to chronic renal failure and required prolonged dialysis followed by renal transplantation, though the leukemia remained in remission. The other patient is also in remission and on maintenance treatment for leukemia. She has persistent proteinuria and is currently undergoing a trial of high-dose steroid therapy.

CONCLUSION

The combination of FSGS with leukemia poses a management challenge to the clinician in terms of further treatment with potentially nephrotoxic drugs, complications of nephrotic syndrome (including infections), and timing of renal transplantation. Future studies should address whether FSGS represents a glomerular response to anthracycline-induced injury in susceptible black persons.