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G Remuzzi

Publications and source records attributed to G Remuzzi.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Strategies for a greater supply of organs for transplantation].

The number of recipients waiting for a solid organ transplantation has increased greatly in the past 5 years. The supply of donor organs during this period has not kept pace, resulting in a large shortage of suitable organs. In an effort to overcome the disparity between supply of donor and demands, various strategies have emerged to expand the existing donor selection criteria. Kidneys from very old donors can be used successfully when a pre-transplant biopsy shows a modest degree of glomerular injury. Kidneys from donors of 50 years or more, or with a history of hypertension and diabetes, or other evidence of renal disease, currently not accepted for single' kidney transplantation, provide excellent function when transplanted together. In contrast, one liver can be enough for two patients. Split-liver transplantation, i.e. sharing one liver between an adult and a pediatric recipient, is becoming routine procedure and has the potential for meeting the need for liver replacement among children without interfering with adult waiting list. Splitting the liver for transplantation in two adults is a further step forward in the more efficient use of hepatic grafts from cadaver donors. Adult-to-adult living donor liver transplantation can further alleviate the pressure in the waiting list, but the risk for the donor must not be underestimated. The decrease in the number of heart-lung transplants in favour of more single and double lung transplants has also made more hearts and more lungs available. It is difficult to quantify the impact of all these procedures on the shortage of organ donors, but the waiting list should be cut by at least one-third for kidney and may be more for liver and lung transplants.

Adult↗
PubMed2001

Whole-blood calcineurin activity is not predicted by cyclosporine blood concentration in renal transplant recipients.

BACKGROUND: In transplant patients, current cyclosporine (CsA) dose monitoring with classic pharmacokinetics has demonstrated limitations. Evaluation of the activity of calcineurin (CN), the serine-threonine phosphatase enzyme target of CsA, has been proposed as a reliable way to optimize CsA dosing. METHODS: CN activity was measured in whole blood in an attempt to overcome the high variability of results obtained previously with peripheral blood mononuclear cells (PBMCs). We also explored, in vitro, a possible relationship between the CsA concentration and CN inhibition in whole blood. Finally, we assessed whether the CsA blood trough concentration correlates with whole-blood CN activity in kidney transplant recipients (n = 15) on maintenance immunosuppression with CsA. RESULTS: In 14 healthy individuals, less scattered CN activity values were documented in whole blood than in the PBMC fraction. Whole-blood CN activity was higher than the sum of the enzyme activity in each cell blood fraction. After ex vivo incubation of whole blood from healthy subjects (n = 5) with increasing concentrations of CsA (50-1000 microg/L for 1 h), a concentration-dependent inhibition of CN activity was found comparable to that in the PBMC fraction. Moreover, in 15 kidney transplant recipients, no relationship was found between CsA pharmacokinetic parameters and CN activity at time 0. However, a highly significant correlation was found between CN area under the CN activity-time curve, which represents the extent of the CN daily inhibition, and CN activity at time 0 (r = 0.79; P <0.01) and at 12 h postdosing (r = 0.96; P <0.01). CONCLUSIONS: Measuring CN activity in whole-blood samples is a reproducible method. In kidney transplant recipients, CsA trough concentrations do not predict baseline CN activity. Moreover, a single CN activity monitoring at baseline or at time 12 h post-CsA dosing may be a useful surrogate for the inhibition of this enzyme by CsA during 12 h.

Buffers↗
PubMed2000

Risk of nonmelanoma skin cancer in Italian organ transplant recipients. A registry-based study.

BACKGROUND: Organ transplant recipients are at an increased risk of nonmelanoma skin cancer. Few data concern heart transplantation and populations from southern Europe. METHODS: A total of 1,329 patients who received their first kidney (1,062 subjects) or heart allograft (267 subjects) were included in a partly retrospective cohort study to evaluate the risk of skin cancer. The incidence rate per 1,000 person-years and the cumulative incidence were computed. Standardized morbidity ratio was estimated by comparison with Italian cancer registry data. To analyze the role of potential prognostic factors, Cox's regression method was used. RESULTS: The overall incidence rate of nonmelanoma skin cancer was 10.0 cases per 1,000 posttransplant person-years (95% confidence interval 8.2-11.7). This estimate was far higher than expected in the general population. The overall risk of developing skin cancer increased from a cumulative incidence of 5.8% after 5 posttransplant years to an incidence of 10.8% after 10 years of graft survival. In a Cox proportional hazard risk model, the most important factors that appeared to favor the development of skin cancer were age at transplantation and sex. After adjustment for age at transplantation and sex, no definite increased risk was documented among heart as compared with kindney transplant recipients. CONCLUSIONS: Our study confirms the increased risk of nonmelanoma skin cancer among organ transplant recipients in a southern European population.

Basal Cell Carcinoma↗
PubMed2000

Thymic dendritic cells express inducible nitric oxide synthase and generate nitric oxide in response to self- and alloantigens.

Thymocytes maturing in the thymus undergo clonal deletion/apoptosis when they encounter self- or allo-Ags presented by dendritic cells (DCs). How this occurs is a matter of debate, but NO may play a role given its ability of inducing apoptosis of these cells. APC (a mixed population of macrophages (Mphi) and DCs) from rat thymus expressed high levels of inducible NO synthase (iNOS) and produced large amounts of NO in basal conditions whereas iNOS expression and NO production were very low in thymocytes. Analysis by FACS and by double labeling of cytocentrifuged preparations showed that DCs and MPhi both express iNOS within APC. Analysis of a purified preparation of DCs confirmed that these cells express high levels of iNOS and produce large amounts of NO in basal conditions. The capacity of DCs to generate NO was enhanced by exposure to rat albumin, a self-protein, and required a fully expressed process of Ag internalization, processing, and presentation. Peptides derived from portions of class II MHC molecules up-regulate iNOS expression and NO production by DCs as well, both in self and allogeneic combinations, suggesting a role of NO in both self and acquired tolerance. We also found that NO induced apoptosis of rat double-positive thymocytes, the effect being more evident in anti-CD3-stimulated cells. Altogether, the present findings might suggest that DC-derived NO is at least one of the soluble factors regulating events, in the thymus, that follow recognition of self- and allo-Ags.

Animals↗
PubMed2000

Epstein-Barr virus-negative lymphoproliferate disorders in long-term survivors after heart, kidney, and liver transplant.

BACKGROUND: Solid organ transplant patients undergoing long-term immunosuppression have high risk of developing lymphomas. The pathogenesis of the late-occurring posttransplantation lymphoproliferative disorders (PTLD) have not yet been extensively investigated. METHODS: We studied 15 patients who developed PTLD after a median of 79 months (range 22-156 months) after organ transplant. Clonality, presence of Epstein-Barr virus (EBV) genome, and genetic lesions were evaluated by Southern blot analysis or polymerase chain reaction. RESULTS: All monomorphic PTLD and two of three polymorphic PTLD showed a monoclonal pattern. Overall, 44% of samples demonstrated the presence of the EBV genome. Within monomorphic PTLD, the EBV-positive lymphomas were even lower (31%). A c-myc gene rearrangement was found in two cases (13%), whereas none of the 15 samples so far investigated showed bcl-1, bcl-2, or bcl-6 rearrangement. The modulation of immunosuppression was ineffective in all patients with monomorphic PTLD independent of the presence of the EBV genome. The clinical outcome after chemotherapy was poor because of infectious complications and resistant disease. With a median follow-up of 4 months, the median survival time of these patients was 7 months. CONCLUSIONS: Late occurring lymphomas could be considered an entity distinct from PTLD, occurring within 1 year of transplant, because they show a histological and clinical presentation similar to lymphomas of immunocompetent subjects, are frequently negative for the EBV genome, are invariably clonal, and may rearrange the c-myc oncogene. New therapeutic strategies are required to reduce the mortality rate, and new modalities of long-lasting immunosuppression are called for.

Adolescent↗
PubMed2000

Chronic proteinuric nephropathies: outcomes and response to treatment in a prospective cohort of 352 patients with different patterns of renal injury.

The Ramipril Efficacy in Nephropathy (REIN) study found that angiotensin-converting enzyme (ACE) inhibitors effectively decreased proteinuria, glomerular filtration rate (GFR) decline (DeltaGFR), and incidence of end-stage renal disease (ESRD) in patients with proteinuric chronic nephropathies. In this study, we prospectively investigated the main clinical determinants of progression and response to treatment in the 352 patients enrolled into the REIN study. Mean DeltaGFR (0.56 +/- 0.05 [SEM] versus 0.21 +/- 0.05 mL/min/1.73 m(2)/mo; P = 0.0001) and incidence of ESRD (30% and 10%; P = 0.0001) were more than twice that in patients with proteinuria of 2 g/24 h or greater of protein compared with those with protein less than 2 g/24 h (relative risk [RR], 4.07; 95% confidence interval [CI], 2.20 to 7.52), as well as in patients with hypertension compared with normotension (mean DeltaGFR, 0.48 +/- 0. 05 versus 0.22 +/- 0.05 mL/min/1.73 m(2)/mon; P = 0.0006; ESRD, 25% versus 10%; P = 0.004; RR, 3.18; 95% CI, 1.38 to 7.32). Hypertension at study entry (P = 0.038), greater mean blood pressure on follow-up (P = 0.002), and urinary protein excretion rate (P = 0.0001) were independent predictors of faster DeltaGFR. DeltaGFR was approximately twofold faster in patients with type 2 diabetes than in those with primary glomerular disease (P = 0.002; including immunoglobulin A [IgA] nephropathy, P = 0.009); nephrosclerosis (P = 0.03), adult polycystic kidney disease (APKD), or chronic interstitial nephritis (P = 0.006). Diabetes at study entry (P = 0. 02) and greater mean blood pressure (P = 0.0001) and urinary protein excretion rate (P = 0.0001) on follow-up were independent predictors of faster DeltaGFR. After correction for baseline covariates, diabetes was also associated with an increased risk for progression to ESRD (RR, 2.39; 95% CI, 1.01 to 5.68; P < 0.05). At multivariate analyses, ramipril significantly decreased DeltaGFR (regression coefficient,-0.23 +/- 0.11 [SEM]; P = 0.036) and ESRD (RR, 2.08; 95% CI, 1.21 to 3.57; P = 0.008) in patients with baseline proteinuria of 2 g/24 h or greater of protein, and the renoprotective effect increased for increasing levels of proteinuria. Ramipril decreased DeltaGFR to a similar extent in normotensive and hypertensive patients (-0.14 +/- 0.11 versus -0.14 +/- 0.09) and significantly limited ESRD in hypertensive patients (RR, 2.03; 95% CI, 1.26 to 3. 26; P = 0.004). DeltaGFR was decreased by 42% in primary glomerular disease (P = 0.017), by 35% in IgA nephropathy, and by 37% in nephrosclerosis, but was not improved in type 2 diabetes, APKD, or interstitial nephritis. At multivariate analyses, ramipril significantly slowed DeltaGFR (-0.24 +/-0.08; P = 0.004) and progression to ESRD (RR, 2.32; 95% CI, 1.36 to 3.96; P = 0.002) in patients without diabetes, but not in patients with diabetes, who tended to have a faster DeltaGFR (+0.62 +/- 0.44) on ramipril therapy. In summary, patients with proteinuria of 2 g/24 h or greater of protein, preexisting hypertension, or type 2 diabetes were faster progressors. Greater blood pressure and degree of proteinuria were the strongest determinants of faster GFR decline. The renoprotective effect of ramipril was similar in patients with normotension and hypertension. Hypertensive patients and those with proteinuria of 2 g/24 h or greater of protein, primary glomerular disease, or nephrosclerosis gained the most from ACE inhibitor treatment. During the study period, those with proteinuria less than 2 g/24 h of protein, type 2 diabetes, or polycystic kidney disease did not benefit by treatment to an appreciable extent.

Adolescent↗
PubMed2000

ACE inhibition improves glomerular size selectivity in patients with idiopathic membranous nephropathy and persistent nephrotic syndrome.

Patients with idiopathic membranous nephropathy (IMN) and persistent nephrotic-range proteinuria are at risk for progression to end-stage renal failure. Whether angiotensin-converting enzyme (ACE) inhibitors are also renoprotective in these patients remains elusive. In 14 patients with IMN (patients) and persistent proteinuria (protein > 3 g/24 h for >6 months), we studied mean arterial pressure (MAP), urinary protein excretion, glomerular filtration rate (GFR), renal plasma flow (RPF), and albumin and neutral dextran fractional clearance after 2 months washout from previous antihypertensive treatment (basal), after 2 months of enalapril (2.5 to 20 mg/d) therapy (posttreatment), and 2 months after enalapril withdrawal (recovery). MAP, proteinuria, and GFR were also measured at the same time points in 6 patients with IMN and persistent overt proteinuria maintained on conventional treatment throughout the study period (controls). Basal MAP, proteinuria, and GFR were similar in the two study groups. However, in patients at the end of the treatment period, MAP (posttreatment, 99.6 +/- 11.2 versus basal, 103.3 +/- 12.1 mm Hg; P < 0.05), proteinuria (posttreatment protein, 5.0 +/- 2.9 versus basal, 7.1 +/- 4.9 g/24 h; P < 0.05), albumin fractional clearance (posttreatment median, 1.7 x 10(-3); range, 0.2 to 22.7 x 10(-3) versus basal median, 4.1 x 10(-3); range, 0.4 to 22. 1 x 10(-3); P < 0.05), and fractional clearance of largest neutral dextrans (radii from 62 to 66 A) were significantly less than basal values. At recovery, MAP significantly increased to 106.6 +/- 11.7 mm Hg (P < 0.001 versus enalapril), but all other parameters remained less than basal values. GFR and RPF were similar at each evaluation. Changes in proteinuria after treatment withdrawal positively correlated (r = 0.72; P < 0.01) with baseline GFR. Theoretical analysis of dextran-sieving data indicated that ACE inhibitor treatment significantly improved glomerular membrane size-selective dysfunction. This effect persisted more than 2 months after treatment withdrawal. No patient had symptomatic hypotension, acute renal function deterioration, or hyperkalemia during enalapril treatment. Thus, in patients with IMN and long-term nephrotic syndrome, ACE inhibitor treatment, but not conventional therapy, improves glomerular barrier size selectivity. The antiproteinuric effect of ACE inhibition is long lasting, especially in patients with more severe renal insufficiency. This is the premise of a long-term renoprotective effect that may limit the need for treatment with more toxic drugs.

Adult↗
PubMed2000

Thrombotic microangiopathy.

The term 'thrombotic microangiopathy' (TMA) describes syndromes of microangiopathic hemolytic anemia, thrombocytopenia, and variable signs of organ impairment, due to platelet aggregation in the microcirculation. The term 'hemolytic uremic syndrome' (HUS) has entered clinical use to describe childhood cases of TMA dominated by renal impairment, while the term 'thrombotic thrombocytopenic purpura' (TTP) refers to adult cases of TMA with predominant neurological abnormalities. HUS and TTP show the same histological lesion characterized by widening of the subendothelial space and microvascular thrombosis and their different manifestations are secondary to the different distribution of the microvascular lesions. Available evidence orients towards endothelial injury as an important factor in the sequence of events leading to the microangiopathic process. Here we provide an overview of the pathophysiology, epidemiology, clinical manifestations, and management of TMA.

Journal Article↗
PubMed2000

ACE genotype and ACE inhibitors induced renoprotection in chronic proteinuric nephropathies1.

UNLABELLED: ACE genotype and ACE induced renoprotection in chronic proteinuric nephropathies. BACKGROUND: Whether angiotensin-converting enzyme (ACE) gene polymorphism affects disease progression and response to ACE inhibitor therapy in nondiabetic proteinuric nephropathies is not clearly established. METHODS: The relationship between insertion/deletion (I/D) genotypes and proteinuria, rate of glomerular filtration rate decline (DeltaGFR)-centrally evaluated by repeated measures of iohexol plasma clearance-and incidence of end-stage renal disease (ESRD) was prospectively evaluated in 212 patients with nondiabetic proteinuric chronic nephropathies enrolled in the Ramipril Efficacy in Nephropathy (REIN) trial, where patients were randomly assigned to ramipril or conventional treatment. RESULTS: The DeltaGFR +/- SEM (-0.38 +/- 0.09 vs. -0.50 +/- 0.08 vs. -0.36 +/- 0.06 mL/min/1.73 m2 per month) and incidence of ESRD (19 vs. 22 vs. 25%) in the three subgroups with the II, ID, and DD genotypes, respectively, were comparable. Of note, DeltaGFR (-0.28 +/- 0.07 vs. -0.43 +/- 0.09 mL/min/1.73 m2 per month) and incidence of ESRD [14% vs. 36%, P = 0.04, RR (95% CI), 2.62 (1.02 to 6.71)] were lower in ramipril than in conventionally treated patients in the DD genotype, but not in the II and ID genotype. Either at univariate (P = 0.04) or at multivariate (P = 0.01) analysis, ramipril significantly predicted a lower incidence of events in DD, but not in II and ID patients. At three months, ramipril decreased proteinuria more effectively in DD (-38.2%) than in the II (-26.7%) or ID (-19.2%) genotype. In DD (but not in II or ID) ramipril-treated patients, a short-term reduction in proteinuria correlated with DeltaGFR over the entire follow-up period (P = 0.02, r = -0.41). CONCLUSIONS: In nondiabetic proteinuric nephropathies, the ACE I/D polymorphism does not predict disease progression, but is a strong predictor of ACE inhibition-associated renoprotection in that proteinuria, DeltaGFR, and progression to ESRD are effectively reduced in patients with the DD, but not in those with the II or ID genotype.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

A novel interpretation of the role of von Willebrand factor in thrombotic microangiopathies based on platelet adhesion studies at high shear rate flow.

Clinical manifestations of thrombotic microangiopathies (TMA) are secondary to platelet aggregation and thrombotic occlusion of the microvasculature of the affected organs. Abnormalities in von Willebrand factor (vWF) in these patients were considered instrumental in promoting the process leading to microvascular thrombosis. We evaluated the capacity of plasma in these patients to induce adhesion of normal platelets and thrombus formation under conditions of controlled fluid shear stress. We also studied vWF multimeric distribution to establish whether abnormalities of this glycoprotein correlate with platelet adhesion and thrombus formation. Plasma from patients in the acute phase and remission showed the same capacity to induce platelet adhesion and thrombus formation at a low level of shear rate (600 sec(-1)) as plasma from control subjects. At a high shear rate (1,500 sec(-1)), platelet adhesion and thrombus dimensions were significantly increased (P: < 0.05) by plasma from patients with TMA compared with controls. The capacity to enhance thrombus formation at high shear stress was present during the acute phase and disease remission and did not correlate with the presence of unusually large vWF multimers. Increased thrombus formation with patient plasma is completely normalized by blocking the interaction of vWF with the platelet receptors, glycoprotein (GP)Ib and GPIIb-IIIa, suggesting that the phenomenon is completely mediated by vWF. Our results suggest the possibility of an intrinsically altered vWF molecule in these patients that is probably more effective than normal vWF in mediating platelet adhesion and thrombus formation.

Adult↗
PubMed2000

Protein traffic activates NF-kB gene signaling and promotes MCP-1-dependent interstitial inflammation.

Mononuclear cells accumulate in the renal interstitium and contribute to renal injury in proteinuric nephropathies. Angiotensin-converting enzyme (ACE) inhibitors reduce protein trafficking and also lessen renal structural and functional damage. Many proinflammatory genes, including monocyte chemoattractant protein-1 (MCP-1), a chemoattractant for monocytes and T lymphocytes, are transcriptionally regulated by nuclear factor-kappa B (NF-kB). We aimed to study NF-kB activation and MCP-1 expression over time in two models of progressive proteinuric nephropathies (5/6 nephrectomy and passive Heymann nephritis [PHN]) and evaluate the effect of antiproteinuric therapy with an ACE inhibitor on these factors. In both models, increased urinary protein excretion over time was associated with a remarkable increase in NF-kB activity, which was almost completely suppressed by reducing proteinuria with lisinopril. NF-kB activation was paralleled by upregulation of MCP-1 messenger RNA and interstitial accumulation of ED-1-positive monocytes/macrophages and CD8-positive T cells. Lisinopril inhibited MCP-1 upregulation and limited interstitial inflammation. In a group of PHN rats with advanced disease and severe proteinuria, a dose of lisinopril high enough to inhibit renal ACE activity failed to reduce proteinuria and also did not limit NF-kB activation, which was sustained over time, along with MCP-1 gene overexpression and interstitial inflammation. These data suggest that NF-kB is activated in the presence of increased protein traffic, enhancing the nuclear transcription of the MCP-1 gene with potent chemotactic and inflammatory properties. This mechanism may help explain the long-term renal toxicity of filtered proteins.

Angiotensin-Converting Enzyme Inhibitors↗