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Increased activation of specific protein kinase C (PKC) isoforms and increased nonenzymatic glycation of intracellular and extracellular proteins [the accumulation of advanced glycation end products (AGEs)] are major mechanistic pathways implicated in the pathogenesis of diabetic complications. Blocking PKC-beta(II) has been shown to decrease albuminuria in animal models of diabetes. To demonstrate a direct relationship between AGEs and the induction and translocation of PKC-beta(II), studies were carried out in rat neonatal mesangial cells, known to express PKC-beta(II) in association with rapid proliferation in post-natal development. Oxidative stress was studied by using the fluorescent probe dichlorfluorescein diacetate. Translocation of PKC-beta(II) was demonstrated by using immunofluorescence and Western blotting of fractionated mesangial cells. Induction of intracellular oxidative stress, increase in intracellular calcium, and cytosol to membrane PKC-beta(II) translocation (with no change in PKC-alpha) were demonstrated after exposure to AGE-rich proteins. These data support the hypothesis that AGEs cause mesangial oxidative stress and alterations in PKC-beta(II), changes that may ultimately contribute to phenotypic abnormalities associated with diabetic nephropathy.

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An overview of the papers published in the last 10 years was performed to evaluate whether treatment with currently available drugs was beneficial in patients with primary IgA nephropathy (IgAN). Eight selected papers involving 196 IgAN patients with moderate or heavy proteinuria, associated in some cases with the nephrotic syndrome, were analysed. The criteria for inclusion were strict, because meta-analysis requires randomised controlled trials with full descriptions. Furthermore, papers were selected in which treatment was performed on IgAN patients with proteinuria, since prognosis is poor in the presence of this sign. The results of statistical analysis show that IgAN patients with heavy proteinuria, whether or not associated with the nephrotic syndrome, benefit from the administration of corticosteroids and/or cytotoxic drugs, as 66.7% of patients had complete or partial remission both in controlled trials and in retrospective studies; renal function also improved in treated patients. In contrast, no beneficial effect was observed in IgAN patients with moderate proteinuria. These results suggest that it is advisable to administer corticosteroids and/or cytotoxic drugs to IgAN patients with heavy proteinuria, irrespective of the association of this condition with the nephrotic syndrome in individual patients.

SUMMARYIn the last few years many investigators have reported the recurrence of primary IgA nephropathy (IgAN)

SUMMARYWe hypothesized that the altered immunoglobulin synthesis and/or lymphocyte ("unciion apparent in patients with IgA nephropathy (IgAN) is due to a primary defeet in lymphokine regulation. In addition, we reasoned that such changes in lymphokine production might be, at least partially, genetically determined. To assess the extent ot'lymphocyte abnormalities, we investigated lhe profile of cytokine production from peripheral blood mononuclear cells (PBMC) in .14 IgAN piilicmsand44 of their first degree relatives, 10 of whom had persistent mierohaematuria. Compared wilh healthy volunteers (o = 34), PBMC from patients showed increased IL-2 production both spontaneously or after phytohaemagglutinin (PHA) (20 /ig/ml) stimulation, whereas lL-4 and interferon-gamma (IFN-y) production were significantly higher only after stimulation. Mierohaemaluric relatives liad a similar pattern of eytokine production, whereas non-microhaematuric relatives showed no significant diflerence versus normals. The altered pattern of cytokine production appeared to be quite specific to IgAN patients and their microhaematuric relatives, because patients with other forms of primary glomerulonephritis (n= 17) did not differ from normal individuals. Patients and relatives that hyperproduced IL-4 were also hyperproducers of IL-2. No such congruence was seen in any other group or with any other pairing of eytokines. We propose that a subpopulation of IgAN patients bear lymphocytes intrinsically hyper responsive. Among those individuals such hyperresponsiveness may be causally related to the pathogenesis and/or character of IgAN.

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