GJB5 association with BRAF mutation and survival in cutaneous malignant melanoma.

BACKGROUND: Gap-junctional intercellular communication is crucial for epidermal cellular homeostasis. Inability to establish melanocyte-keratinocyte contact and loss of the intercellular junction's integrity may contribute to melanoma development. Connexins, laminins and desmocollins have been implicated in the control of melanoma growth, where their reduced expression has been reported in metastatic lesions. OBJECTIVES: The aim of this study was to investigate connexin 31·1 (GJB5) expression and identify any association with BRAF mutational status, prognosis of patients with melanoma and mitogen-activated protein kinase (MAPK) inhibitor (MAPKi) treatment. METHODS: GJB5 expression was measured at RNA and protein level in melanoma clinical samples and established cell lines treated (or not) with BRAF and MEK inhibitors (MEKi), as well as in cell lines which developed MAPKi resistance. Findings were further validated and confirmed by analysis of independent datasets. RESULTS: Our analysis reveals significant downregulation of GJB5 expression in metastatic melanoma lesions compared with primary ones and in BRAF-mutated vs. BRAF-wildtype (BRAFWT ) melanomas. Likewise, GJB5 expression is significantly lower in BRAFV600E compared with BRAFWT cell lines and increases on MAPKi treatment. MAPKi-resistant melanoma cells display a similar expression pattern compared with BRAFWT cells, with increased GJB5 expression associated with morphological changes. Enhancement of BRAFV600E expression in BRAFWT melanoma cells significantly upregulates miR-335-5p expression with consequent downregulation of GJB5, one of its targets. Furthermore, overexpression of miR-335-5p in two BRAFWT cell lines confirms specific GJB5 protein downregulation. Reverse transcriptase quantitative polymerase chain reaction analysis also revealed upregulation of miR-335 in BRAFV600E melanoma cells, which is significantly downregulated in cells resistant to MEKi. Our data were further validated using the TCGA_SKCM dataset, where BRAF mutations associate with increased miR-335 expression and inversely correlate with GJB5 expression. In clinical samples, GJB5 underexpression is also associated with patient overall worse survival, especially at early stages. CONCLUSIONS: We identified a significant association between metastases/BRAF mutation and low GJB5 expression in melanoma. Our results identify a novel mechanism of gap-junctional protein regulation, suggesting a prognostic role for GJB5 in cutaneous melanoma.

Toll-like receptor 4 expression is increased in circulating mononuclear cells of patients with immunoglobulin A nephropathy.

We investigated Toll-like receptors (TLR-3, -4 and -7) expression in circulating mononuclear cells of patients with immunoglobulin A nephropathy (IgAN), a disease with debated relationships with mucosal immunity. TLR-4 expression (detected by fluorescence activated cell sorter) and mRNA transcriptional levels (Taqman) were significantly higher in patients with IgAN than in healthy controls (P = 0.00200 and P = 0.0200). TLR-3 and TLR-7 were not modified significantly. In IgAN patients proteinuria was correlated significantly with TLR-4 expression (P = 0.0312). In a group of nephrotic syndromes, TLR-3, -4 and -7 expression was similar to healthy controls. A significant difference in TLR-4 expression and mRNA levels was found between very active IgAN patients (proteinuria > 1 g/1.73 m(2)/day in association with severe microscopic haematuria) and inactive patients (proteinuria < 0.5 g/1.73 m(2)/day, with absent or minimal haematuria). No correlation with levels of aberrantly glycosylated IgA1, age, renal biopsy features or therapy was found. This study shows for the first time an up-regulation of TLR-4 in circulating mononuclear cells of patients with IgAN, particularly in association with proteinuria and heavy microscopic haematuria.

Oxidative stress in IgA nephropathy.

IgA nephropathy (IgAN) is characterized by mesangial deposits of IgA1, likely due to accumulation of IgA immune complexes. The activation of intracellular signaling mostly results in oxidative stress, as detected in mesangial cells cultured with aberrantly glycosylated IgA or IgA aggregates and in renal biopsies of patients with IgAN. Signs of altered oxidation/antioxidation balance have been detected in sera and/or in erythrocytes of patients with IgAN, including increased levels of lipoperoxide or malondialdehyde and reduced activity of superoxide dismutase, catalase and glutathione peroxidase. Moreover, increased levels of a marker of oxidative stress, advanced oxidation protein products (AOPPs), have been reported to be significantly associated with proteinuria and disease progression in patients with IgAN. AOPPs are often carried by albumin and can in turn enhance the oxidative stress in the circulation. Recent research suggests that the nephrotoxicity of aberrantly glycosylated IgA1 in IgAN is enhanced in the presence of systemic signs of oxidative stress, and it is tempting to hypothesize that the level of the oxidative milieu conditions the different expression and progression of IgAN.

[Audit on quality of life of patients with chronic kidney disease on dialysis and after transplant]. / Audit sulla qualità di vita nei pazienti in insufficianza renale cronica, dialisi e trapianto.

Since the improvement of quality of life (QOL) in patients with chronic disease on dialysis (D-CKD) has been demonstrated to have significant effects on clinical outcome, QOL has been included among the principal targets for these patients. QOL is among the objectives of the Healthy People 2010 program of the United Nations and CKD is one of the 18 focus areas of the program. The process of improving clinical outcome for D-CKD patients is obviously correlated with the continuing attempts to improve the adequacy of dialysis, and this remains a milestone. Some recent studies, including the HEMO study, have demonstrated that the present standards for dialytic efficiency are adequate for morbidity and mortality outcomes. However, these concepts are rapidly evolving and there are emerging factors which should be monitored, such as a) frequency of hospitalization, b) QOL, c) patient's satisfaction, and d) transplantation rate. Each aspect should be taken into consideration when the general well-being of D-CKD patients is at stake. However, there is a lack of validated standards, and there are confounding effects related to different geographical areas, different degrees of morbidity, and different therapies. Health is defined by the WHO as the complete feeling of well-being, and transplantation obviously is a way to overcome the many difficulties encountered by D-CKD patients. It is true that QOL after transplant is affected by uncertainty about the final result, fear of having to go back on dialysis, or anger about unexpected complications. For these reasons special questionnaires have been designed for transplanted patients (e.g., SF-36). These indicate an improvement of QOL for transplanted compared with D-CKD patients, although QOL remains below the level of that of the healthy population. Post-transplant QOL tends to improve over time and will become superimposable to that of the healthy population in the long run. It is of paramount importance that each dialysis and transplantation center provide psychological support not only to patients but also to doctors and nurses.

[Non-immunological therapy in nephropathies leading to chronic renal failure and in post-transplant chronic renal dysfunction]. / La terapia non immunologica delle nefropatie con insufficienza renale cronica e della disfunzione cronica da trapianto.

With its aging population, the Western world is experiencing a significant increase in the prevalence of chronic kidney disease, which has actually been defined as ''pandemic''. The high mortality and comorbidity, especially in terms of cardiovascular disease, have led to a significant increase in hospitalizations and rising public health expenditure, setting a trend that will become unsustainable in the next decades, even in the most developed countries. These epidemiological data have underlined the need for prevention campaigns and urged researchers and clinicians to develop new and more specific treatments able to slow down the progression of chronic kidney disease towards dialysis. To obtain such results, a deeper understanding of the pathogenetic mechanisms of nephropathy progression is mandatory. Once sclerosis is established and the initial pathogenetic noxa, whether or not involving the glomeruli, has been extinguished, the sclerotic progression of different nephropathies follows a standard pathway, irrespective of the initial cause. The achievement of an effective therapy for this condition, in native kidneys as well as transplanted organs, is the third-millennium challenge for nephrologists. In this review we will first describe the main risk factors and pathogenetic mechanisms involved in nephropathy progression and then discuss the results obtained with drugs that basic research has identified as potentially useful in experimental animal models as well as rigorous clinical trials.

[Immunoglobulin A (IgA) and its cellular receptors: Recent advances and new pathogenetical hypothesis]. / L' immunoglobulina A (IgA) ed i suoi recettori cellulari nella nefropatia a depositi IgA: recenti conoscenze e nuove ipotesi patogenetiche.

Researchers have always been focusing their interest on IgA nephropathy, a nephropathy named after a class of immunoglobulin, and on circulating IgA in these patients. However, serum level studies conducted on IgA and IgA containing immune complexes have not fulfilled the expectations of providing useful tools for diagnosis and prognosis of this renal disease. Over recent years interest has grown on qualitative properties of IgA, particularly IgA1, the mostly represented subclass in renal deposits. The sugar composition of the short carbohydrate chains characteristic of the IgA1 hinge region has been thoroughly investigated, and a defective glycosylation of serum IgA1 in IgAN patients was detected with increase in desialylated and degalactosylated carbohydrate chains, and exposure of internal N-acetylgalactosamine residues. These aberrantly glycosylated IgA1 have the properties of self-aggregation, auto-antibody enhancement with IgA1/IgG immunocomplexes formation, and activation of complement and nuclear transcription factors such as NF-kB. Among others, aberrantly glycosylated IgA1 react with FC RI receptor on peripheral lymphomonocytes and, after shedding, the complex is released in form of macromolecular IgA. At mesangial level the nephrotoxicity of aberrantly glycosylated IgA1 seems to be mediated by the transferrin receptor (TfR) binding, selectively expressed on mesangial cells. This report aims at reviewing the most recent knowledge on IgA synthesis alterations and the subsequent biological effects on the pathogenesis of this nephritis so widespread in Europe.

[Kidney transplantation in children]. / Il trapianto di rene nel bambino.

Indications, procedures, complications, pharmacokinetics and outcomes of renal transplantation are different in children and in adults. Subjects <18 yrs old, are often included in a unique list as in Italy, benefiting from donors <15 yrs old, and the waiting time is reduced to <12 months in 71% of cases. The risk of thrombosis limits the use of donors <2 yrs and trans-plantation in infants <1 yr. The age at kidney transplantation is <5 yrs in 20-30% of children. In Italy living-related trans-plantation (LRT) is performed in 7% of cases, while in the USA it is more common (57%) and is often pre-emptive before entering dialysis (24%). Current therapy tends to reduce steroid treatment doses and, optimizing induction therapy with IL-2R inhibitors, using tacrolimus or mycophenolate or sirolimus. Transplanted patient survival is better in children than in adults (94-98% at 5 yrs). Infections, cardiovascular diseases and neoplasia induce 34, 15 and 12% of deaths, respectively, at 10 yrs; morbidity for infections and lymphoproliferative disease is increasing. Acute rejections declined from 70% in 1987 to 31% in 2002 in cadaveric transplantation (CT) and renal survival at 3 yrs increased from 50% in 1985 to 82% for CT and up to 92% in LRT. In adolescents (11-17 yrs old) renal survival is lower than in infants and in adults <65 yrs old. Renal losses are due to chronic transplant nephropathy (32%), vascular thrombosis (13%) and the recurrence of the original nephropathy (focal glomerulosclerosis up to 50%, membrano-proliferative glomerulonephritis up to 30%, and primary hyperoxaluria up to 90% if combined kidney-liver transplantation is not performed). Growth improves after transplantation particularly in children <5 yrs, while it is not completely satisfactory in adolescents. Overall, results indicate that kidney transplantation in children has very much improved and will offer in the near future even more favorable outcomes.

Single kidney function: effect of acute protein and water loading on microalbuminuria.

The hyperfiltration induced by an acute response to an oral protein and water load was investigated to ascertain whether it can modify the urinary albumin excretion (UAE) in the microalbuminuric range by further increasing the glomerular filter permeability. To this end, six patients with a single kidney selected as having microalbuminuria on a regular diet without the clinical or laboratory data of overt renal disease and eight healthy subjects received a short-term protein and water load (150 g of meat-derived protein and 1 liter of water). In patients with one kidney, mean basal UAE values were significantly higher than in control subjects (p less than 0.006), whereas endogenous creatinine clearance values were only slightly lower (p greater than 0.05). One hour after the protein and water load, an abrupt increase in microalbuminuria levels was found in patients with one kidney and mean UAE values were significantly higher than in control subjects (p less than 0.002), whereas mean creatinine clearance values were significantly lower in patients than in control subjects (p less than 0.01). High UAE (p less than 0.002) and low creatinine clearance (p less than 0.002) values were maintained over the following four hours in patients with one kidney. These data suggest that in the single kidney with reduced renal functional reserve, an oral protein and water load magnifies the pre-existing loss of glomerular permselective properties due to chronic hyperfiltration as manifested by a further increase in microalbuminuria.

The influence of blood transfusion on cellular immunity.

To evaluate the effect of transfusion on immunity, we studied some immunological parameters in 14 uremic patients treated with 3 blood transfusions (5 with HLA-compatible and 9 with random transfusions). Before transfusions 8/14 patients were DNCB-negative; both spontaneous and active E-rosettes were below normal range. The parameters of humoral immunity (S-Ig, C3, C4, IC, CRP) were normal. After both the first and second transfusions an increase in T- and B-lymphocytes was found. The third transfusion led to a more pronounced and prolonged immunosuppression in patients treated with compatible transfusions than in those treated with random transfusions. Our findings suggest that blood transfusion--HLA-compatible transfusion in particular--results in an impairment of the lymphocyte role.

In vitro study of Fc-receptor function in autoimmune diseases.

A simple test for studying in vitro Fc-receptor function of mononuclear phagocytes is described. Immune phagocytosis is analyzed as a dynamic phenomenon by using nearly pure suspensions of monocytes incubated for diverse times with autologous erythrocytes sensitized with highly purified IgG. In a series of normal volunteers and patients with vasculitis a strict correlation has been found between this in vitro assay and the measure of splenic clearance of IgG-coated red blood cells (RBC), the classical approach for studying in vivo macrophage Fc-receptor function by using sodium chromate 51Cr as tag. The use of this in vitro assay appears to be valuable mainly in cases requiring repeated measurements of Fc-receptor function for monitoring the course of disease or the effects of therapy.

Aberrantly glycosylated IgA molecules downregulate the synthesis and secretion of vascular endothelial growth factor in human mesangial cells.

To gain insight into the glomerular capillary repair mechanisms in immunoglobulin A (IgA) nephropathy, we focused on vascular endothelial growth factor (VEGF-A) and nitric oxide (NO). Because abnormal glycosylation of serum IgA has been shown in IgA nephropathy, we examined whether VEGF-A and NO production by mesangial cells (MCs) could be modulated by aberrantly glycosylated (desialylated or degalactosylated) IgA. VEGF-A and NO synthase (NOS) gene expression were examined by reverse-transcriptase polymerase chain reaction (RT-PCR) or Northern blot analysis, and VEGF-A peptide, by capture enzyme-linked immunosorbent assay and NOS activity as production of tritium ([(3)H]) citrulline from [(3)H] arginine. Semiquantitative densitometric analysis of RT-PCR experiments showed a significant downregulation of VEGF-A messenger RNA (mRNA) in MCs incubated with aberrantly glycosylated IgA. This resulted in decreased release of VEGF-A in culture medium (P: < 0. 01). NOS activity and inducible NOS (iNOS) mRNA were enhanced by aberrantly glycosylated IgA (both P: < 0.01). No modulation of constitutive NOS mRNA was found. The depression of the VEGF-A production induced by aberrantly glycosylated IgA was mediated by NO because it was completely reversed by the NOS inhibitor, N:omega-nitro-L-arginine methyl ester. The NO donor, sodium nitroprusside, induced a bimodal modulation of VEGF; although low concentrations (0.0001 nmol/L) increased VEGF-A synthesis, greater concentrations (1,000 nmol/L) depressed it. In conclusion, we report negative control of VEGF-A synthesis in MCs by aberrantly glycosylated IgA, mediated by enhanced iNOS activity. We speculate that both increased iNOS activity and depressed VEGF-A synthesis might have a role in impairing vascular repair and favor sclerosis in IgA nephropathy.

Cytokine mRNA expression by cultured rat mesangial cells after contact with environmental lectins.

We previously demonstrated that gliadin, a lectinic component of gluten, induces IgA mesangial deposits in orally immunized mice, binds in vitro polymeric IgA and cultured rat mesangial cells modulating their arachidonic acid metabolism. We investigated the effects of gliadin and other environmental lectins on some mesangial cell functions, including synthesis and release of cytokines and lipid mediators. Several lectins, particularly gliadin, affected the mRNA expression of c-myc and c-fos, two proto-oncogenes involved in the transcriptional enhancement of the gene cascade, which are markers of cell growth, differentiation and mitosis. Lectins modulated the ability of cultured rat mesangial cells to express mRNA for cytokines involved in the inflammation and in the regulation of the immune response. TNF-alpha and IL-6 mRNA transcription were enhanced by gliadin and other lectins, and TNF release was variably increased. Conversely, IL-1 production was less affected or slightly depressed. PAF production was not detectable while PGE2 was generally reduced and TXB2 enhanced. Gliadin was one of the lectins most active on the mesangial cells, and its effects were reversed by the addition of N-Acetylglucosamine, a sugar specific for some lectinic bindings, suggesting a carbohydrate interaction. The effects of the various lectins were distinct and only partially convergent, ruling out an aspecific mesangial cell activation. These data suggest that lectins might interfere with mesangial cell functions and modify the mesangial cell homeostasis.

Primary biliary cirrhosis and rheumatic diseases: a clinical, immunological and immunogenetical study.

Clinical investigation of Primary Biliary Cirrhosis (PBC) patients showed an elevated frequency of rheumatic disorders, as well as their frequent appearance in asymptomatic PBC. Anticentromere region antibodies in PBC patients were pathognomonic for concomitant complete or incomplete CREST syndrome. These antibodies were only found on the HEp2 cell substrate. The constant finding of immune-complexes (IC) with IgM antibody component suggests that they play a role in the pathogenesis of PBC. No statistically significant correlation was found between the amount and classes of circulating IC, HLA class I antigens and rheumatic disorders during PBC.

Treatment of IgA nephropathy with angiotensin converting enzyme inhibitors: design of a prospective randomized multicenter trial.

Although several in vitro studies and clinical observations suggest that ACE-inhibitors (ACE-I) are a promising treatment for IgA nephropathy (IgAN), meta-analysis of published data is not yet conclusive. Therefore, a European double-blinded, prospective, randomized therapeutic trial was designed to evaluate ACE-I treatment benefits in young IgAN patients (<35 years old) with persistent moderate proteinuria (>1<3.5 g/day/1.73 m2) and fair renal function (creatinine clearance >50 mL/min/1.73 m2). Patients enrolled are randomly assigned to benazepril (0.2 mg/kg/day) or placebo. Patients should be enrolled within a five year recruitment period (end on December 2003) for a total duration of follow-up of six years (end on December 2004). Hypertension and some genetic, histological and immunological factors will be evaluated to clarify their eventual role in the final response to ACE-I treatment.

Use of alkaline rinsing solution to prevent hypersensitivity reactions during hemodialysis: data from a multicentre retrospective analysis.

BACKGROUND: Hypersensitivity reactions (HSRs) can be enhanced by contact phase system activation leading to bradykinin (BK) generation. In patients treated with angiotensin converting enzyme inhibitors (ACE-I), an impaired kinin degradation can magnify the phenomenon. We have previously demonstrated that the electronegative charge of the dialysis membrane (e.g. AN69) and other cofactors including diluted blood buffer power promote BK generation, and that kallikrein synthesis on diluted plasma may be inhibited by keeping the pH value above 7.4. Our in vitro and ex vivo studies have demonstrated that the use of an alkaline solution to rinse both filter fluid compartments before their clinical use can inhibit the activation of mediators that are likely to be involved in HSRs. METHODS: The present study was aimed at gathering data from a multicenter retrospective analysis of HSRs in 15 Italian centers, with special attention to the precautions chosen to avoid recurrence, and at evaluating whether a rinsing procedure maintaining the pH of the diluted blood above 7.4 may prevent further HSRs. RESULTS: HSRs were reported in 54 patients on dialysis treatment between January 1995 and June 1997. 39/54 HSRs occurred when AN69 was used. In 44.4% of cases, HSRs were associated with ACE-I treatments. The HSR prevention modalities varied considerably among the centers. Two thirds of the nephrologists did not change their dialysis prescription but tried to modify the acidic environment of the patient's diluted blood at the first contact with the dialysis device using an alkaline rinsing procedure (BioPrime with alkaline solution). In other cases ACE-I withdrawal or a change of dialysis membrane was adopted. Thirty-six patients who received alkaline rinsing of the filters were monitored for a total of 686 months (median 17.6 months/patient) to control HSR recurrences. None of the patients enrolled in this study developed new episodes of HSRs. CONCLUSIONS: Even if considered with the caution called for by this kind of study, which was retrospective and uncontrolled, our data suggest a protective effect of the alkaline rinsing procedure with buffered solutions in the development of HSRs.

Providing the right stuff: feeding children with chronic renal failure.

The progressive loss of renal function in children with chronic renal failure (CRF) has a negative influence on their nutritional status and statural growth. Supportive therapies with 1-25 dihydroxy-vitamin D3, recombinant erythropoietin and growth hormone have significantly improved the biochemical and clinical features but the success of these therapies is largely related to an appropriate diet, with adequate protein/caloric intakes. Children more than adults have minimal protein requirements to avoid malnutrition and growth impairment FAO/WHO and RDA recommendations save as guidelines for a correct diet in children with CRF. Following these allowances leads to a "normoproteic" diet, with a protein intake which is often half the unrestricted one in Western European countries, but which is still likely to be not enough to protect against renal deterioration. Indeed the European Study Group for Nutritional Treatment of CRF in children failed to show a significant effect of diet on the mean decline of glomerular filtration rate over two years.

The polymorphonuclear neutrophil (PMN) immunohistological technique: detection of immune complexes bound to the PMN membrane in acute poststreptococcal and lupus nephritis.

Twenty-nine patients with Systemic Lupus Erythematosus (SLE) and 6 patients with Acute Poststreptococcal Glomerulonephritis (APGN) have been studied with the polymorphonuclear neutrophil (PMN) immunohistological technique to detect in vivo interaction between circulating immune complexes (IC) and PMN membrane receptors. Patients have been studied both at diagnosis and during follow-up and the results compared to those yielded by the C1qSP test. Our data provide evidence that the PMN immunohistological technique may prove a useful tool in monitoring IC disease. Moreover, elution studies may allow the detection and characterization of the antigens in the PMN-bound IC.

Mediterranean diet and primary IgA nephropathy.

Since IgA nephropathy can be experimentally induced by alimentary antigens, mechanisms of oral immunization might be supposed also in human primary IgA nephropathy (PIgAGN). IgA immune complexes (IgAIC) are thought to play a major role in PIgAGN, hence this parameter was monitored in six PIgAGN patients subjected to diets excluding gluten, meat or eggs respectively and selected as having persistent urinary activity and high IgAIC levels. On gluten-free diet IgAIC significantly decreased over 3 different periods of 10 days (Student's t-test p 1 less than 0.03, Rank-Signed test p 2 less than 0.02), 1 month (p 1 less than 0.007, p 2 less than 0.02) and 6 months (p 1 less than 0.05, p 2 less than 0.02). IgAIC significantly increased again on a gluten containing diet over 1 month (p 1 less than 0.008, p 2 less than 0.04) and 3 months (p 1 less than 0.02, p 2 less than 0.04). After 6 months on a gluten-free diet, all patients had normal IgAIC values and decreased IgA2 subclass-IgAIC, in agreement with the hypothesis of withdrawal of an antigen challenging the mucosal immune system. These data indicate a relationship between a gluten-containing diet and high levels of IgAIC in PIgAGN patients, suggesting that dietetic factors might play a role in the different geographical distribution of this nephropathy.

Microalbuminuria in single kidney patients: relationship with protein intake.

Experimental models have shown that the reduction in renal mass induces an increase in glomerular filtration rate of the remnant nephrons, leading to proteinuria and glomerular sclerosis. Since the presence of microalbuminuria - increased urinary albumin excretion (UAE) undetectable by routine assays - can be an early sign of this phenomenon, UAE in the normo- and microalbuminuric range was measured in 24 single kidney patients with negative Albustix. Nephrectomy had been performed in 22 cases 1 to 28 years before, mostly because of renal lithiasis. Patients were selected as being normotensive, normoglycemic and free of recurrent urinary infections or stones. On regular diet (mean protein intake 1.2 g/kg/day), UAE mean values were significantly higher in single kidney patients than in 20 controls both in supine position during overnight rest (clinostatism) (37.71 +/- 56.32 vs 2.56 +/- 2.27 micrograms/min, p less than 0.001) and in erect position during moderate physical effort (orthostatism) (67.31 +/- 86.12 vs 4.59 +/- 5.73 micrograms/min, p less than 0.004). Microalbuminuria was observed in 18/24 single kidney patients in clinostatism and 15/24 in orthostatism. A subgroup of 14 patients was also studied on different protein dietetic regimens. After one month on a 0.6 g/kg/day protein containing diet, UAE mean levels significantly decreased in comparison to those found on regular diet (clinostatism: 26.15 +/- 35.93 vs 49.24 +/- 70.29 micrograms/min, p less than 0.02; orthostatism: 31.73 +/- 46.97 vs 68.92 +/- 83.53 micrograms/min, p less than 0.001). One month after a 1.6 g/kg/day protein diet UAE mean values significantly increased (clinostatism 83.99 +/- 88.04 micrograms/min, p less than 0.001; orthostatism: 117.19 +/- 116.12 micrograms/min, p less than 0.001). Our data indicate that microalbuminuria, detectable in the majority of patients with a single kidney, can be modulated by different protein intakes.

Glomerular permselectivity to macromolecules in reflux nephropathy: microalbuminuria during acute hyperfiltration due to aminoacid infusion.

Reflux nephropathy is an important cause of chronic renal failure in children. After the parenchymal scar, the progression is thought to be mediated by glomerular hypertension in remnant nephrons resulting in modifications in permselectivity to macromolecules. Proteinuria correlates with a progressive course. The glomerular permselectivity to macromolecules in basal conditions and after acute hemodynamic stress was investigated in 28 children whose bilateral vesico-ureteric reflux (VUR) had been previously surgically corrected (meanly 5.6 years before) and with normal creatinine clearance (CrCl). Bilateral renal scarring (0 to 8 scale for both kidneys) was 4.3 +/- 1.6. Albuminuria (UAE) was evaluated in basal conditions and under acute hyperfiltration induced by amino acid (Aa) infusion. After isotonic saline at 310 ml/hour/1.73 m2, 6 mg/kg/min of Aa were infused for 2 hrs. UAE was significantly higher than controls in basal conditions (p < 0.01), and further increased after Aa infusion (p < 0.02). Microalbuminuria was detectable in 53.5% of the children in basal conditions and in 64.3% after Aa. Also urinary beta 2 microglobulin significantly increased at the end of the test (p < 0.001). CrCl significantly increased at the first hour (p < 0.05). Children with severe renal parenchymal scarring had greater UAE (p < 0.01) and beta 2M (p < 0.02) values after provocative test than those with mild renal damage. In 8 children GFR and ERPF were measured by means of inulin and p-hippurate clearance respectively. The variations in UAE during Aa infusion were significantly correlated with GFR dynamics (p < 0.05) while they were not influenced by ERPF modifications.(ABSTRACT TRUNCATED AT 250 WORDS)