PubMed HealthSearch

Biomedical subjects

T Bertani

Publications and source records attributed to T Bertani.

At least 19 recordsLinked to original sources

Bindarit retards renal disease and prolongs survival in murine lupus autoimmune disease.

As an alternative to classical immunosuppressants in experimental lupus nephritis, we looked at bindarit, 2-methyl-2-[[1-phenylmethyl)-1H-indazol-3-y1]methoxy]propanoic acid, a novel molecule devoid of immunosuppressive effects, which selectively reduces chronic inflammation in rat adjuvant arthritis. Two groups of NZB/W mice (N = 55 for each group) were given bindarit, (50 mg/kg/day p.o.) or vehicle starting at 2 months of age. Mice were sacrificed at 2, 6, 8 and 10 months or used for survival studies. Bindarit delayed the onset of proteinuria (% proteinuric mice, bindarit vs. vehicle, 6 months: 0 vs. 33% and 8 months: 7% vs. 60%, P < 0.005; 10 months: 53% vs. 80%) and significantly (P < 0.05) protected from renal function impairment (serum BUN, bindarit vs. vehicle: 8 months, 30 +/- 3 vs. 127 +/- 42; 10 months, 53 +/-5 vs. 140 +/- 37 mg/dl). Appearance of anti-DNA antibodies was retarded and survival significantly (P < 0.0001) prolonged by bindarit (% survival, bindarit vs. vehicle: 8 months, 100% vs. 80%; 10 months, 87% vs. 40%; 12 months, 27% vs. 20%). Bindarit significantly limited glomerular hypercellularity, interstitial inflammation and tubular damage. Renal expression of monocyte chemoattractant protein (MCP-1) mRNA (Northern blot) markedly increased (7 - 12-fold in 8- 10-month-old mice vs. 2-month-old) during the progression of nephritis in association with mononuclear cell infiltration. Bindarit completely prevented MCP-1 up-regulation. In another series of experiments, bindarit (0.25% and 0.5% medicated diet, N = 16 for each group) when started at 4.5 months of age in NZB/W mice improved survival in respect to untreated mice (N = 17) in a dose-dependent manner (% survival: 8 months, 94% and 100%, respectively, vs. 47%; 10 months, 75% and 100% vs. 35%; 12 months, 31% and 75% vs. 12%). Survival was even more prolonged when bindarit (0.5% medicated diet) was combined with a low dose of methylprednisolone (1.5 mg/kg i.p.), which that only partially modifies proteinuria and survival of lupus mice, in an additional group of animals (N = 16). Thus, at 14.5 months when all mice given bindarit alone died, 50% of mice on combined therapy were still alive (P < 0.023). Studies are needed to establish whether bindarit may function as a steroid sparing drug in human lupus.

Animals

Unselective inhibition of endothelin receptors reduces renal dysfunction in experimental diabetes.

Chronic nephropathies are associated with enhanced renal synthesis of endothelin (ET)-1. A recent study demonstrated that an ET(A) receptor antagonist given to diabetic rats at the moment of disease induction prevented the development of renal injury. Here we investigated whether an unselective ET(A)/ET(B) receptor antagonist, PD 142,893, was renoprotective when given to streptozotocin diabetic rats when animals were already proteinuric. The effect of PD 142,893 was compared with that of an ACE inhibitor, lisinopril, known to retard progressive renal disease in experimental and human diabetes. PD 142,893 normalized systemic blood pressure, reduced urinary protein and albumin excretion, and ameliorated renal blood flow in diabetic rats, but it did not affect such parameters in control rats. Lisinopril had a renoprotective effect comparable to PD 142,893, although lisinopril controlled systemic blood pressure better. Northern blot analysis of ET-1 mRNA revealed upregulation of ET-1 gene in the diabetic kidney. Similar results were obtained by in situ hybridization in glomeruli and tubuli of diabetic rats. Both treatments remarkably attenuated exaggerated renal ET-1 gene expression. These data suggest that ET-1 is a contributory mediator of kidney damage in diabetes and indicate that ET receptor antagonists may represent a new therapeutic mean for treatment of progressive diabetic nephropathy.

Albuminuria

The renoprotective properties of angiotensin-converting enzyme inhibitors in a chronic model of membranous nephropathy are solely due to the inhibition of angiotensin II: evidence based on comparative studies with a receptor antagonist.

In several models of renal disease progression, angiotensin-converting enzyme (ACE) inhibitors reduced proteinuria and limited glomerulosclerosis, which suggested that reduction of renal angiotensin II (Ang II) activity is crucial for the preservation of glomerular structure and function. However, it cannot be ruled out that other hormonal systems, including inhibition of the bradykinin breakdown, also play a role. We compared the effects of chronic treatment with the ACE inhibitor lisinopril with those of a specific Ang II receptor antagonist, L-158,809, on proteinuria and renal injury in passive Heymann nephritis (PHN), a model of immune renal disease that closely resembles human membranous nephropathy, with long-lasting proteinuria followed by tubulointerstitial damage and glomerulosclerosis. Passive Heymann nephritis was induced with 0.5 mL/100 g of rabbit anti-Fx1A antibody in 24 male Sprague-Dawley rats. The animals were divided into three groups of eight rats each, and were given the following in the drinking water on a daily basis: lisinopril (40 mg/L), L-158,809 (50 mg/L), or no therapy. Treatment started at day 7 (proteinuria was already present) and lasted 12 months. Eight normal rats were used as controls. Untreated PHN rats developed hypertension, while rats with PHN given lisinopril or L-158,809 all had systolic blood pressure values even lower than those of normal rats. Urinary protein excretion progressively increased with time in untreated PHN rats, who developed tubulointerstitial damage and glomerulosclerosis. Both lisinopril and L-158,809 exhibited a potent antiproteinuric effect and preserved glomerular and tubular structural integrity at a similar extent. Renal gene expression of transforming growth factor-beta and extracellular matrix proteins was also effectively reduced by the two treatments. These results indicate that ACE inhibitors and Ang II receptor antagonists are equally effective in preventing renal injury in PHN and suggest that the renoprotective effects of ACE inhibitors in this model are solely due to inhibition of Ang II.

Angiotensin II

Mycophenolate mofetil limits renal damage and prolongs life in murine lupus autoimmune disease.

Classical immunosuppressants like cyclophosphamide give excellent results in human lupus nephritis. However, they augment malignancies and viral infections. Here we investigated the effect of the new immunosuppressant agent, mycophenolate mofetil (MMF), in New Zealand Black x New Zealand White (NZBxW) F1 hybrid mice, a model of genetically determined immune complex disease that mimics systemic lupus in humans. MMF has a selective antiproliferative effect on T- and B-lymphocytes, inhibits antibody formation and blocks the glycosylation of lymphocyte glycoproteins involved in the adhesion of leukocytes to endothelial cells. Two groups of NZBxW mice were used: group 1 (N = 20) given daily MMF (60 mg/kg p.o.) and group 2 (N = 15) given daily vehicle alone. Treatment started at three months of age and lasted until the death of the animals. Results showed that percentage of proteinuric mice was significantly reduced by MMF treatment and serum BUN levels were also lower than vehicle. MMF had a suppressive effect on autoantibody production and protected animals from leukopenia and anemia. Life survival of MMF treated lupus mice was significantly improved in respect to untreated animals. Thus, MMF delayed renal function deterioration and prolonged life survival in murine lupus nephritis. MMF has been already recognized as reasonably well tolerated in renal transplant patients and despite its gastrointestinal toxicity its overall safety profile appears superior to azathioprine. Human studies are needed to establish whether MMF may function as a steroid-sparing drug in lupus nephritis.

Animals

Renal expression of monocyte chemoattractant protein-1 in lupus autoimmune mice.

Mononuclear cell infiltration in glomeruli and renal interstitium is a prominent feature of some types of glomerulonephritis, including lupus nephritis. The mechanism(s) underlying monocyte influx into the kidney is not fully understood. Recently, monocyte chemoattractant protein-1 (MCP-1) has been identified as a chemotactic factor involved in the recruitment of monocytes/macrophages in the glomeruli of rats with mesangioproliferative as well as anti-glomerular basement membrane glomerulonephritis. In the study presented here, renal MCP-1 mRNA expression in New Zealand Black x New Zealand White (NZB/W) F1 mice, a model of genetically determined immune complex disease that mimics systemic lupus in humans, was investigated. Northern blot analysis revealed a single 0.7 kb MCP-1 transcript of very low intensity in kidneys from 2-month-old NZB/W mice that had not yet developed proteinuria nor renal damage. Message levels, which increased markedly with the progression of nephritis and in association with mononuclear cell infiltration, were 10- and 15- fold higher in 8-10-month-old mice than in 2-month-old mice. By in situ hybridization, increased expression of MCP-1 mRNA was demonstrated in glomeruli and, even more striking, in tubular epithelial cells. Western blot analysis demonstrated increased expression of MCP-1 protein in kidneys of 10-month-old NZB/W mice, consistent with MCP-1 mRNA data. When NZB/W mice were treated with cyclophosphamide up to 12 months of age, expression of MCP-1 in the renal tissue remained low, the influx of inflammatory cells did not appear, and glomerular and tubular structures remained well preserved. These data suggest that elevated MCP-1 might act as a signal for inflammatory cells to infiltrate the kidney in lupus nephritis.

Animals

Structural basis of diabetic nephropathy in microalbuminuric NIDDM patients: a light microscopy study.

The objective of the study was to evaluate early structural changes occurring in patients with non-insulin-dependent diabetes mellitus (NIDDM) and microalbuminuria by light microscopy. Basal renal biopsy was performed in patients who were subsequently randomized to different antihypertensive treatments. Fourteen NIDDM patients aged 36-65 years (duration of diabetes 9 +/- 7 years) with microalbuminuria (mean urinary albumin excretion 66 +/- 49 micrograms/min) underwent percutaneous renal biopsy. Control biopsies were obtained from five patients of similar age undergoing nephrectomy for renal neoplasia with normal renal function and no history of renal disease. Control and diabetic biopsies were processed by light microscopy and stained with haematoxylin and eosin, periodic acid Schiff, Masson's trichrome and silver methenamine. The percentage of globally sclerotic glomeruli was evaluated. Glomerular volume was determined using perimeter analysis. A semiquantitative assessment (range 0 to 3+) was made of mesangial sclerosis, interstitial fibrosis, tubular atrophy, arteriosclerosis and arteriolar hyalinosis. Glomerular volume was significantly increased in diabetic as compared to control glomeruli (3.2 +/- 8 vs 1.8 +/- 7, p < 0.01). Mesangial sclerosis (0.9 vs 0, p < 0.0001) and arteriolar hyalinosis (0.91 vs 0.2, p < 0.022) were significantly higher in diabetic compared to control subjects. No significant differences between diabetic and control subjects were found in the percentage of globally sclerotic glomeruli or in the extent of interstitial fibrosis, tubular atrophy and arteriosclerosis. Thus NIDDM patients with microalbuminuria show histological findings consistent with diabetic nephropathy characterized by glomerular hypertrophy, mesangial sclerosis and arteriolar hyalinosis. However, the renal histological changes are mild and appear less marked than in insulin-dependent diabetic patients.

Adult

A study of low-nutrient diets used for aging studies in the rat.

The effects of diets of low caloric value on rats used in aging studies were investigated. Groups of 85 Sprague-Dawley rats were fed ad libitum from 3 months of age on three different diets containing 8 or 10 Megajoule (MJ) of metabolizable energy and 80 or 100 g of crude protein/kg. Body weights, food consumption, and morphological and biochemical parameters were monitored throughout life. Kidneys were examined histologically. Rats given the diet with highest energy and protein ate less food, attained greater weights, and had larger abdominal fat deposits than those on the lower energy diets. They had a raised proteinuria, and nearly half developed glomerulosclerosis and tubulo-interstitial damage by 26 months. There was no significant difference in mortality between the groups, and no other serious abnormalities were observed. It is concluded that rats can be maintained into old age with no signs of nutritional inadequacy on diets with lower energy and protein contents than those in general use.

Abdomen

Dissociation between antiproteinuric and antihypertensive effect of angiotensin converting enzyme inhibitors in rats.

To clarify whether angiotensin converting enzyme (ACE) inhibitors prevent progressive renal injury directly by their antihypertensive effect we administered the ACE inhibitor lisinopril to male MWF/Ztm rats as a single daily dose that lowered blood pressure for only 9 of 24 h. We investigated the effects of this treatment in short- and long-term studies and compared them with another antihypertensive drug, the calcium channel blocker nitrendipine, given to partially control blood pressure as done with the ACE inhibitor. In untreated animals systemic hypertension, proteinuria, and glomerulosclerosis developed spontaneously with age, and lisinopril reduced systemic hypertension and prevented proteinuria and glomerular lesions. Nitrendipine, despite similar blood pressure control, was ineffective in preventing both proteinuria and glomerulosclerosis. After 2 mo of treatment glomerular capillary pressure was significantly reduced by lisinopril and slightly but significantly increased by nitrendipine, compared with untreated controls. The ultrafiltration coefficient was significantly higher in lisinopril than in controls and not significantly changed by nitrendipine. With both drugs, however, glomerular hemodynamic effects were observed only at a few hours after administration and were abolished before the next administration. No significant changes in glomerular tuft volume were observed in treated and untreated animals after 2 and 6 mo of observation. Thus ACE inhibitor, despite only partial control of systemic blood pressure, effectively prevented proteinuria and glomerular injury. Comparable blood pressure control obtained with a calcium channel blocker was not associated with renal protection. These results suggest that ACE inhibitors could protect glomerular microcirculation by a mechanism that is not directly related to their antihypertensive action.

Alpha-Globulins

Evidence that an angiotensin-converting enzyme inhibitor has a different effect on glomerular injury according to the different phase of the disease at which the treatment is started.

In rats with streptozotocin-induced diabetes, the effect of an angiotensin-converting enzyme (ACE) inhibitor on the evolution of glomerular injury according to the time at which the treatment is started with respect to the onset of the disease was studied. Three groups of animals were used, a control Group 1 and two groups of diabetic rats treated with insulin (Groups 2 and 3). The latter were monitored until urinary protein excretion reached 40 to 50 mg/24 h (on average, 23 wk after the induction of the diabetes). At this time, Group 2 continued to receive insulin alone, whereas Group 3 was also given the ACE inhibitor moexipril for 8 more wk. Untreated diabetic rats showed a moderate increase in systolic blood pressure that was normalized by moexipril administration. Urinary protein excretion progressively increased during the 8-wk follow-up in untreated diabetics that, at the end of the study, developed moderate glomerular sclerosis. Moexipril treatment lowered urinary protein excretion to a normal range and completely prevented glomerular injury. Three other groups of rats were similarly treated, except that moexipril treatment was started later on (when proteinuria reached 100 to 200 mg/24 h, on average, 32 wk after the induction of diabetes), and were monitored for another 8 wk. Untreated and treated diabetics had comparable blood glucose levels throughout. Systolic blood pressure, significantly increased in untreated diabetic rats, was effectively controlled by moexipril administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors

Effects of angiotensin-converting enzyme inhibition on glomerular capillary wall ultrastructure in MWF/Ztm rats.

Previous studies have documented that treatment with angiotensin-converting enzyme (ACE) inhibitors prevents spontaneous proteinuria and enhances the glomerular ultrafiltration coefficient in male MWF/Ztm rats. The aim of this study was to study whether these beneficial effects of ACE inhibitors on glomerular capillary wall function are derived from the preservation of its ultrastructure. Conventional morphometrical analysis of kidney tissue, by light and electron microscopy, was used to quantify glomerular structural changes in the male MWF/Ztm rats treated with the ACE inhibitor cilazapril for 2 and 6 months and in age-matched untreated controls. At the end of the observation periods, both systolic blood pressure and urinary protein excretion were significantly reduced in treated animals as compared with controls. Glomerular volume increased significantly with time but was comparable in control and in treated rats. Surface area available for filtration (measured as peripheral capillary wall) was comparable in control and in treated animals at the same time and increased significantly with time only in treated rats. Mesangial volume was significantly higher in cilazapril-treated animals than in controls after 2 months of treatment and was comparable after 6 months. ACE inhibitor treatment did not induce significant ultrastructural changes such as basement membrane thickness, configuration of epithelial podocytes, and the width and the frequency of the epithelial slit diaphragms. These results indicate that the previously observed increase in the glomerular ultrafiltration coefficient by an ACE inhibitor in these animals is not the consequence of changes in filtering surface area but likely reflects an increase in membrane hydraulic permeability.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors

Prognosis of untreated patients with idiopathic membranous nephropathy.

BACKGROUND: Defining the most appropriate treatment for patients with idiopathic membranous nephropathy is a matter of controversy. The course of the disorder is often benign, and the immunosuppressive regimens used in some patients have uncertain benefits and substantial risks. We studied the natural history of idiopathic membranous nephropathy in patients who received only symptomatic therapy. METHODS: We prospectively studied 100 consecutive patients (68 men and 32 women; mean [+/- SD] age, 51 +/- 17 years) with biopsy-proved idiopathic membranous nephropathy. The patients received diuretic or antihypertensive drugs as needed, but no glucocorticoid or immunosuppressive drugs. We examined the patients and measured their urinary protein excretion and serum creatinine concentrations every 6 months for a mean of 52 months. RESULTS: Twenty-four (65 percent) of the 37 patients followed for at least five years had complete or partial remission of proteinuria; in 6 others (16 percent), end-stage renal disease developed, and they required dialysis. As calculated by the Kaplan-Meier method, the estimated probability (+/- the standard error of the estimate) of retaining adequate kidney function was 88 +/- 5 percent after five years and 73 +/- 7 percent after eight years. The prognosis was poorer in men and in patients over 50 years of age, but not in patients with the nephrotic syndrome, hypertension, or hypercholesterolemia. CONCLUSIONS: Most untreated patients with idiopathic membranous nephropathy maintain renal function for prolonged periods and are likely to have spontaneous remission. These results do not support the use of glucocorticoids and immunosuppressive drugs in patients with idiopathic membranous nephropathy.

Adult

A specific endothelin subtype A receptor antagonist protects against injury in renal disease progression.

We have recently reported that renal preproendothelin-1 gene is up-regulated in rats with renal mass reduction (RMR) and that time-dependent increase in urinary excretion of the corresponding peptide correlates with renal disease progression. Here we evaluated whether a specific endothelin subtype A (ETA) receptor antagonist, FR139317, reduced signs of disease activity in this model. Two groups of rats were given FR139317 or its vehicle (saline) from day 7 to day 60 after the surgical procedure. Sham-operated animals were the control group. Blood pressure, urinary protein excretion and serum creatinine were evaluated at days 0, 7 (before FR139317 or saline administration), 30, 45 and 60. At sacrifice, histological evaluation of renal tissue was performed. The results showed that ETA receptor blocker reduced the abnormal permeability to proteins, limited glomerular injury and prevented renal function deterioration thus confirming the working hypothesis. These findings suggest that this class of compounds may eventually prove useful in the treatment of human progressive nephropathies.

Animals

Glomerulonephritis.

Advances in cell and molecular biology have generated fresh insights into the mechanisms of glomerular injury, a field with very few substantial advances in the past 20 years. Currently, the nature of renal antigens involved in the immune reaction is being identified, as in the case of Goodpasture antigen. Many recent studies focus on T-cell and macrophage functions in glomerulonephritis that initiate acute inflammatory events and determine glomerular disease progression. Recent data established that after inflammatory cell migration to the glomerulus, subsequent damage depends on cell adhesion to cytokine-activated endothelial cells, a process mediated by a variety of specialized molecules. It seems easy to predict that within the next few years these studies will have a major impact on the way these diseases are treated. Already, evidence indicates that, in experimental animals, monoclonal antibodies blocking adhesive molecules prevent or reduce glomerular damage. Cytokines and growth factors, by promoting resident cell proliferation and modulating extracellular matrix synthesis and metabolism, modulate acute glomerular injury and subsequent scarring. Recent studies have established that glomerular injury is related to urinary protein excretion, an issue that has been approached in humans by combining studies on barrier size selectivity with morphometry. An emerging concept suggests that leaking of proteins through the glomerular capillary has an intrinsic renal toxicity that is likely due to proximal tubular over-reabsorption of the abnormally filtered macromolecules. Data are also accumulating that may soon link the degree of tubulointerstitial injury with glomerular damage and subsequent development of renal scarring.

Animals

Heterogeneous nature of renal lesions in type II diabetes.

The nature of renal damage in patients with type II diabetes remains unclear. This study was directed to evaluate pathologic changes in 52 patients affected by type II diabetes with overt clinical nephropathy by conventional and morphometric techniques. The duration of diabetes ranged from 6 to 384 months, urinary protein excretion ranged from 0.9 to 9.2 g/24 h, and serum creatinine ranged from 0.9 to 9 mg/dL. Specimens were examined semiquantitatively by light microscopy, immunofluorescence, and electron microscopy. Glomerular tuft cross-sectional area was measured by a versatile computer system. Pathologic examination revealed three distinct patterns arbitrarily defined as Classes 1, 2, and 3. Class 1 included 19 patients with typical changes of diabetic nephropathy characterized by a high score of glomerulosclerosis (mean score, 2.1), marked glomerular hypertrophy (23,632 microns2), and arteriolar hyalinosis (mean score, 2). There was a positive correlation between glomerulosclerosis and arteriolar hyalinosis scores (P < 0.05). Class 2 included 16 patients showing chronic and aspecific changes. As compared with Class 1 patients, these patients had less glomerulosclerosis (mean score, 1.3) and less arteriolar hyalinosis (mean score, 0.8) but more severe ischemic glomerular lesions (mean score, 1.4) and arteriosclerosis (mean score, 2). Class 3 included 17 patients showing glomerular disease superimposed on diabetic glomerulosclerosis. There were no differences in age, mean duration of diabetes, renal function, urinary protein excretion, and mean arterial pressure among the three classes of patients. This study indicates that renal lesions in patients with type II diabetes manifest in a quite heterogeneous fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Short- and long-term effect of angiotensin II receptor blockade in rats with experimental diabetes.

The short- and long-term effects of specific angiotensin II (AII) receptor blockade on the evaluation of glomerular injury in moderately hyperglycemic diabetic rats were studied. Three groups of animals were used, a control group, a group of diabetic rats treated with insulin, and a group of insulin-treated diabetic rats receiving the AII receptor antagonist losartan in drinking water. After 4 to 6 wk of observation, diabetic rats showed higher systolic blood pressure and GFR than normal controls. Losartan treatment prevented both systolic blood pressure and GFR rise. Three other groups of rats, similarly treated for a 1-yr period, were used for renal functional and morphologic evaluation. Diabetic animals had higher urinary protein excretion and glomerulosclerosis incidence than did normal controls. Losartan significantly prevented proteinuria and glomerulosclerosis. Evaluation of the sieving properties of the glomerular membrane by Ficoll fractional clearance showed an important increase in the filtration of this marker in diabetic animals, as compared with that in controls, and almost complete prevention of this change in losartan-treated animals. Theoretical analysis of fractional clearance data with a heteroporous model of glomerular size-selectivity showed that in diabetic animals the size of membrane pores was increased uniformly, as compared with that in controls. These changes were completely prevented by the AII receptor antagonist. The results presented here strongly indicate that reduction of AII activity plays a crucial role in the preservation of glomerular structure and function and suggest that the favorable effects previously observed with angiotensin-converting enzyme inhibition in this model depend directly on the reduction of AII activity.

Angiotensin Receptor Antagonists

Renal protective effect of angiotensin-converting enzyme inhibition in aging rats.

Aging in rats with intact kidneys is associated with changes in selective glomerular permeability to macromolecules resulting in proteinuria and progressive glomerular sclerosis. We have previously reported that angiotensin-converting enzyme (ACE) inhibition in Munich Wistar Fromter/Ztm (MWF/Ztm) rats resulted in a significant reduction of proteinuria, in respect to untreated animals, and that treated animals were protected against the development of glomerular sclerotic lesions. The present study was designed to establish whether ACE inhibition protects against glomerular injury in male Sprague-Dawley rats, which develop spontaneous proteinuria and glomerulosclerosis with age. The effect of ACE inhibition was tested when proteinuria was already present. Four-month treatment with the ACE inhibitor perindopril prevented the increase in systolic blood pressure, compared with vehicle-treated animals, and significantly decreased urinary protein excretion of aging rats. Partial protection of the development of glomerular sclerosis was also observed.

Aging