PubMed Health⌕ Search

Biomedical subjects

L Gesualdo

Publications and source records attributed to L Gesualdo.

At least 55 records · Page 3Linked to original sources
PubMed1995

Effects of in vitro nutrient supplementation on polymorphonuclear cell respiratory burst in primary IgA nephropathy.

Since recent findings have pointed out a key role for reactive oxygen species in kidney diseases, we investigated superoxide anion (O2-) and hydrogen peroxide (H2O2) generation by peripheral blood polymorphonuclear cells (PMN) in 20 patients with primary IgA nephropathy (IgAN). Results provided evidence for a significant enhancement of O2- and H2O2 production in IgAN subjects in comparison to patients affected by hypertensive renal injury and healthy donors. Among the IgAN group, the highest oxidative metabolism was observed in patients with severe histologic lesions. On the other hand, in vitro vitamin and/or trace element supplementation to PMN suspensions led to a down modulation of their oxidative responsiveness. These data were further supported by the assessment of O2- release on a kinetic basis. Nutrient pretreatment was in fact able to antagonize either the IgAN-related shortening of the lag period or the increase of maximum O2- production rate following agonist stimulation. Taken together, these findings indicate that an exaggerated PMN oxidative metabolism occurs in IgAN and suggest a potential role for micronutrients in the modulation of PMN metabolic pathway.

Adolescent↗
PubMed1995

Endotoxins modulate chronically tumour necrosis factor alpha and interleukin 6 release by uraemic monocytes.

We examined in vivo the release of tumour necrosis factor alpha (TNF alpha) and interleukin 6 (IL-6) by uraemic monocytes upon stimulation with endotoxin-contaminated bicarbonate concentrate. Twelve uraemic patients underwent 1-month-subsequent periods of standard haemodialysis (SHD) with cuprophane (CU), a high-complement-activating membrane (6 patients), or haemodiafiltration (HDF) with polyacrylonitrile (PAN), a low-complement-activating membrane (6 patients), by using a dialysate prepared with either non-sterile bicarbonate concentrate tanks (phase 1) or sterile bicarbonate concentrate bags (phase 2). TNF alpha and IL-6 concentrations were determined in monocyte supernatants by ELISA; endotoxin levels in bicarbonate concentrates were measured by a chromogenic limulus amoebocyte lysate (LAL) assay. A significant increase in LAL reactivity was found in bicarbonate concentrate tanks compared to sterile bags (P < 0.001). Non-sterile dialysate caused a significant (P < 0.001) predialytic increase in monocyte TNF alpha release as compared to controls and non-dialysed uraemic patients. One month treatment with sterile bicarbonate significantly decreased TNF alpha predialytic activity in monocyte supernatants (P < 0.001) to levels closer to those of non-dialysed uraemic patients. A similar decrease was observed for IL-6 production. Dialytic treatment induced a further increase in both TNF alpha and IL-6 production, particularly in phase 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cultured human mesangial cells produce both type 1 and type 2 plasminogen activator inhibitors.

Cultured human mesangial cells (HMC) derived from normal kidneys have been shown to synthesize tissue-type plasminogen activator (t-PA) and excess amounts of PA inhibitor type 1 (PAI-1). Conflicting results have been obtained concerning the production of urokinase-type PA (u-PA) and efforts to show PA inhibitor 2 (PAI-2) met with failure. We evaluated the fibrinolytic profile of cultured HMC lines obtained from 12 patients with renal carcinoma and one cadaveric kidney donor. Subconfluent cells (third passage) were incubated overnight in serum-free medium. t-PA, u-PA, PAI-1 and PAI-2 antigens were assayed by ELISA methods and PA and PAI activities by amidolytic methods both in conditioned medium (CM) and cell extracts (CE). Besides PAI-1, PAI-2 antigen was detected in all but one HMC lines. At variance with the former, which was largely released in the culture medium, PAI-2 was mainly cell-associated. t-PA antigen was found in all but two cell lines while u-PA antigen was detected in relatively high concentrations in 8 cell lines. PA activity, identified as u-PA by functional and immunological criteria, was measured in CM of six of the eight u-PA producing cell lines, whereas PAI activity was undetectable or very low in CM of all cell lines, suggesting that PAI-1 was largely inactive. Functional assays of cell extracts demonstrated the presence of PA activity, again identified as u-PA, only in samples (five lines) containing u-PA antigen in excess over PAI-2. PAI activity was found instead in the extracts in which the inhibitor was higher than the activator (six lines) and was identified as PAI-2, as it inhibited u-PA but not single-chain t-PA and was neutralized by a polyclonal anti-PAI-2 antibody. The heterogeneous fibrinolytic pattern of HMC lines was confirmed by mRNA analysis of three representative lines. Results were similar when HMC lines at passage five were used, except that the u-PA content was significantly reduced both in CM and CE. These findings indicate that the fibrinolytic profile of cultured HMC is more complex than previously reported. The production of large amounts of PAI-2 may represent an additional control mechanism of proteinase activity.

Blotting, Northern↗
PubMed1994

Trapidil inhibits human mesangial cell proliferation: effect on PDGF beta-receptor binding and expression.

Mesangial cell (MC) proliferation, a histopathologic feature common to many human glomerular diseases, is regulated by several growth factors through their binding to specific cell surface receptors. Platelet-derived growth factor (PDGF) is a peptide exerting a potent mitogenic activity on MC. Recently, an increased expression of both PDGF protein and its receptor has been localized in the mesangial areas of several experimental as well as human proliferative glomerulonephritides (GN). Thus, it may be postulated that the inhibition of PDGF action could prevent MC proliferation during mesangial proliferative GN. Trapidil, an antiplatelet drug, has been shown to inhibit the growth of several cell types both in vitro and in vivo. The present study was aimed at evaluating the effect of Trapidil on human MC in vitro. The addition of 100 to 400 micrograms/ml Trapidil significantly reduced cell proliferation induced by different growth factors (FCS, PDGF-BB, bFGF, EGF), the highest inhibitory effect being on PDGF-BB stimulated MC growth. The effect of the drug was dose-dependent and seemingly specific: aspirin was devoid of any anti-proliferative action, while dypiridamole proved to be toxic. Receptor binding experiments showed that Trapidil competitively inhibited 125I-PDGF-BB binding to its cell surface receptors, without inducing receptor internalization, at least after short-term (2 hr) incubation. In contrast, long-term (48 hr) exposure to 400 micrograms/ml Trapidil caused a sharp increase of PDGF-BB binding. Similar effects on cell proliferation and 125I-PDGF-BB binding were observed when NIH-3T3 fibroblasts were exposed to the test substance.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1994

Profiles of immunoregulatory cytokine production in vitro in patients with IgA nephropathy and their kindred.

We hypothesized that the altered immunoglobulin synthesis and/or lymphocyte function apparent in patients with IgA nephropathy (IgAN) is due to a primary defect in lymphokine regulation. In addition, we reasoned that such changes in lymphokine production might be, at least partially, genetically determined. To assess the extent of lymphocyte abnormalities, we investigated the profile of cytokine production from peripheral blood mononuclear cells (PBMC) in 34 IgAN patients and 44 of their first degree relatives, 10 of whom had persistent microhaematuria. Compared with healthy volunteers (n = 34), PBMC from patients showed increased IL-2 production both spontaneously or after phytohaemagglutinin (PHA) (20 micrograms/ml) stimulation, whereas IL-4 and interferon-gamma (IFN-gamma) production were significantly higher only after stimulation. Microhaematuric relatives had a similar pattern of cytokine production, whereas non-microhaematuric relatives showed no significant difference 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 cytokines. We propose that a subpopulation of IgAN patients bear lymphocytes intrinsically hyperresponsive. Among those individuals such hyperresponsiveness may be causally related to the pathogenesis and/or character of IgAN.

Adolescent↗
PubMed1994

Expression of platelet-derived growth factor receptors in normal and diseased human kidney. An immunohistochemistry and in situ hybridization study.

We studied the expression of PDGF-alpha and -beta receptors in 10 normal and 40 pathologic human kidneys (five minimal change disease, five membranous nephropathy, 25 IgA nephropathy, five lupus nephritis), by both immunohistochemistry and in situ hybridization techniques. In normal-appearing kidneys, both PDGF-alpha and -beta receptors were expressed at the glomerular and interstitial level, the latter receptor more intensely than the former. The distribution and degree of expression of both receptors in nonproliferative glomerulonephritides were comparable with those found in normal-appearing kidneys. PDGF-beta receptor gene and protein expression were upregulated in proliferative nephritides both at the glomerular and the interstitial level and strictly correlated with the grade of histologic lesions. Finally, PDGF beta receptor expression was observed at a low level in normal-appearing renal vessels, and strikingly increased in injured arteries. Diseased kidneys displayed only a slight increase of PDGF-alpha receptor expression, chiefly at the interstitial level. Noteworthy, a few cases of lupus nephritis showed a moderate increase of PDGF-alpha receptor also at the glomerular level. These data establish PDGF-beta receptor activation as a candidate for driving glomerular and interstitial proliferation and, probably, expansion of extracellular matrix in proliferative glomerulonephritis, while the role of PDGF-alpha receptor activation at the renal level remains to be elucidated.

Cells, Cultured↗
PubMed1993

C5b-9 generation and cytokine production in hemodialyzed patients.

The role of the complement system in the induction of cytokine release is controversial. Plasma terminal C complex C5b-9 along with Bb and C4d fragments were evaluated in 22 patients during routine acetate or bicarbonate hemodialysis using cuprophane membranes and hemodiafiltration (HDF) or acetate-free-biofiltration (AFB) using polyacrylonitrile (PAN) membranes. In a subgroup of six uremic patients we also evaluated the release of tumor necrosis factor (TNF alpha) and interleukin-6 (IL-6) from monocytes before and after six subsequent sessions with bicarbonate-cuprophane, HDF and AFB-PAN. At beginning of the dialysis increased plasma C5b-9 levels were found in patients treated by acetate or bicarbonate-cuprophane. Moreover, a rapid significant (P < 0.001) increase of C5b-9 levels occurred in both groups 15 minutes after the onset of the hemodialysis procedure with a plateau at 180 minutes. In contrast, only a slight increase in the plasma C5b-9 levels was observed in patients dialysed with HDF or AFB using PAN membranes. This increase was more pronounced with HDF at 0 minutes compared with controls. A positive linear correlation was found in all patients between C5b-9 generation and plasma Bb levels at different times in the dialysis session. The production of C4d fragment remained unchanged in all groups, indicating that C5b-9 complex generation is due to the prevalent alternative complement pathway activation. The pattern of cytokine production strictly resembled the complement system activation and C5b-9 generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Glomerular hemodynamics and eicosanoid synthesis in a rat model of IgA nephropathy.

We sought to study glomerular pathophysiology in a model of IgA nephropathy (IgAN). Preliminary experiments with oral immunization indicated that Lewis rats had higher IgA levels and IgA/IgG ratios than Wistar, Fischer or Sprague-Dawley rats. Six groups of Lewis rats were studied: four continuously orally immunized for eight weeks with bovine gamma globulin (BGG) in the drinking water, the other two non-immunized controls. Groups of immunized rats were treated with a thromboxane receptor antagonist (SQ 29,485) and/or a thromboxane synthase inhibitor (UK 38,485). After systemic challenge, microscopic hematuria was present in 84% of immunized rats not given anti-thromboxane drugs versus 18% of non-immunized rats (P less than 0.01). Immunized rats showed predominantly IgA glomerular deposits with lesser IgG and C3, and produced more glomerular thromboxane than controls, but no significant increase in prostaglandin E2. Immunized rats also had reduced GFR and RPF, but not a reduced filtration fraction, compared to controls. Thromboxane synthase inhibitor diminished glomerular thromboxane and increased prostaglandin E2 in immunized rats. Anti-thromboxane therapy reduced hematuria and apparently re-established the RPF but not the GFR in immunized rats, yielding a reduced filtration fraction. We propose that increased thromboxane, in concert with mesangial contraction that is unaffected by anti-thromboxane drugs, contributes to the pathophysiology in this model of IgAN.

Animals↗
PubMed1992

Regulation of macrophage colony-stimulating factor in liver fat-storing cells by peptide growth factors.

Macrophage colony-stimulating factor (M-CSF) selectively promotes mononuclear phagocyte survival, proliferation, and differentiation. The production of this factor within the liver may be necessary to support the relatively long-term survival of circulating monocytes as they migrate into tissues and differentiate into macrophages. We studied the constitutive expression and the effects of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF) on M-CSF mRNA levels and secretion of M-CSF in murine liver fat-storing cells (FSC), vascular pericytes likely involved in the development of liver fibrosis. By Northern analysis, using a murine M-CSF cDNA, FSC constitutively express two major transcripts of 4.4 and 2.2 kb, similar to those detected in mouse L cells, used as a control. Exposure to 10 ng/ml PDGF or bFGF increased M-CSF mRNA levels. Peak effects were observed at 3 and 6 h for PDGF and bFGF, respectively, returning to baseline levels by 12 h. Under basal conditions, detectable amounts of M-CSF, measured by radioimmunoassay, were found in cell supernatants conditioned for 8 and 24 h. PDGF and bFGF markedly stimulated the release of M-CSF as early as 8 h, an effect persisting for at least 24 h. These findings suggest that liver FSC release M-CSF upon stimulation by PDGF and bFGF and may contribute to the activation of resident or infiltrating cells in inflammatory liver diseases.

Animals↗
PubMed1992

Primary IgA nephropathy: the relevance of experimental models in the understanding of human disease.

IgA nephropathy is the most common form of primary glomerulonephritis worldwide. About one quarter of patients progress to terminal renal failure 10 years after the apparent clinical onset. Therefore, the disease represents a social problem in terms of number of patients requiring maintenance hemodialysis. Despite the intense research effort devolved to clarify the pathogenesis of IgA nephropathy, the exact relationship linking the several factors involved is still unknown. In this review we analyze the experimental works reported since 1979, when the first animal model of IgA nephropathy was published by Rifai et al. We also discuss the interplay between experimental data and clinical observations to maximize the information gathered from the different animal models. Finally, we report the new insights into the role played by cytokines, growth factors and autacoids.

Animals↗
PubMed1992

Immunopathological aspects of immunoglobulin A nephropathy and other mesangial proliferative glomerulonephritides.

Immunoglobulin A nephropathy (IgAN) is an immune complex (IC) glomerulonephritis (GN) that represents one of the most common forms of primary glomerular disease. Proliferation of mesangial cells and the increase of mesangial matrix are histological hallmarks of mesangioproliferative GN. Increased serum levels of IgA, polymeric IgA, IgA rheumatoid factor, IgA-IC, and spontaneous or pokeweed mitogen-induced production of IgA by peripheral blood mononuclear cells are major humoral immune alterations reported in IgAN. Recently, we focused on the role of cytokines and growth factors in the mediation of glomerular injury. Platelet-derived growth factor, transforming growth factor beta, interleukin (IL)-1 and IL-6 are expressed by and act on mesangial cells. Increased expression of platelet-derived growth factor was found in both an active model of IgAN and in renal biopsies of patients with proliferative GN. A strict correlation between increased expression of B-chain mRNA and mesangial proliferation was found. Cytokines such as IL-1, interferon gamma, and IL-6, released by infiltrating mononuclear cells or produced locally by mesangial cells, affect the glomerular response to IgA-IC. In a passive murine experimental model of IgAN, IL-1 and interferon gamma increased mesangial hypercellularity, whereas IL-6 was highly pathogenic when associated to IL-1. In conclusion, classical immunological mechanisms in mesangial GN could interact with other pathways involving cytokines and growth factors in the progression of glomerular injury.

Animals↗
PubMed1991

Platelet-derived growth factor expression in mesangial proliferative glomerulonephritis.

Proliferation of mesangial cells and expansion of mesangial matrix are common histologic features of proliferative glomerular disease, a frequent cause of renal failure. Proliferation of glomerular mesangial cells occurs in response to platelet-derived growth factor (PDGF), and these cells release PDGF and express PDGF A and B chain mRNAs. However, all studies relating PDGF to potential changes in glomerular structure and function to date have been performed in vitro. To explore the role of PDGF in proliferative glomerulonephritides, we studied the expression of PDGF in vivo in two animal models of IgA nephropathy with different histologic patterns of glomerular injury: either predominant mesangial proliferation or expansion of mesangial matrix. Increased expression of PDGF and PDGF B-chain mRNA in whole kidneys from diseased mice was demonstrated by immunohistochemical techniques and by solution hybridization assay, respectively. Immunohistochemically, PDGF was localized primarily within the mesangial area of glomeruli and to a much lower extent in interstitium. The increased PDGF expression correlated with the degree of hypercellularity and clinical features of the disease. In addition, PDGF expression was increased in some forms of human glomerulonephritis, characterized by mesangial proliferation. These findings suggest that PDGF may be a major contributor to mesangial cell proliferation seen in proliferative glomerulonephritides.

Animals↗
PubMed1990

Defective oral tolerance promotes nephritogenesis in experimental IgA nephropathy induced by oral immunization.

Oral tolerance, an important feature of the mucosal immune system, appears to protect against immune-mediated disease by blunting production of systemic IgG and IgM antibody directed toward immunogens chronically present at mucosal surfaces. In this study, we explored the role of oral tolerance and mucosal immunoregulation in an experimental model of IgA nephropathy (IgAN), an important form of nephritis in humans. Cyclophosphamide and estradiol were used to inhibit the expression of oral tolerance, which otherwise develops after chronic oral presentation of Ag. BALB/c mice given drinking water containing 0.1% bovine gamma globulin (BGG) continuously for 14 wk were randomly assigned to groups given either 2 mg of cyclophosphamide i.p., 2 mg of estradiol s.c. or both drugs. Groups of control mice received neither BGG nor drugs. In three separate experiments, a low percentage of saline-treated orally immunized mice had microscopic hematuria (0 to 20%), as did nonimmunized controls (0 to 20%). However, 58 to 83% of mice given estradiol and/or cyclophosphamide at appropriate times developed significant hematuria. If drugs were given at suboptimal times, only 25 to 56% of mice developed hematuria. Drug-treated immunized mice also had more serum IgG and IgM anti-BGG antibodies than control and saline groups. Immunofluorescence showed significantly more glomerular deposits of IgG, IgM, and C3 in drug-treated immunized mice compared to saline-treated immunized and normal untreated control mice. Hematuria and glomerular deposits of IgG, IgM, and C3 paralleled serum IgG and IgM antibody. All immunized mice showed significant mesangial IgA and BGG deposits and there were no differences in such deposits between saline- and drug-treated immunized mice. We suggest that blunting of oral tolerance with promotion of systemic IgG and IgM antibody production leads to nephritis in chronically orally immunized mice and that glomerular immune complexes containing IgG and/or IgM promote complement deposition and hematuria in IgAN. Analogous defects in oral (or more generally mucosal) tolerance could play a role in the genesis of symptomatic human IgAN.

Administration, Oral↗
PubMed1990

Enzymolysis of glomerular immune deposits in vivo with dextranase/protease ameliorates proteinuria, hematuria, and mesangial proliferation in murine experimental IgA nephropathy.

The therapeutic effects of saccharolytic and proteolytic enzymes were investigated in models of IgA nephropathy. Mesangial glomerulonephritis was induced in mice by intravenous injection of preformed soluble immune complexes of dextran sulfate and either IgA (J 558) or IgM (MOPC 104 E) anti-dextran MAb (passive model) or by immunization with DEAE dextran (active model). In the passive model, only 30-40% of dextranase-treated mice given IgA or IgM immune complexes had mesangial Ig or dextran deposits, compared with 100% of saline-treated controls (P less than 0.01). There was no significant difference in mice given only protease. In the active model, dextranase and protease separately each reduced glomerular dextran and C3 deposits, and hematuria (P less than 0.01). Dextranase also reduced the glomerular IgA deposits (20 vs. 100% of saline-treated mice) and the frequency and severity of mesangial matrix expansion (both P less than 0.02), but did not reduce the modest IgG or IgM codeposits. Protease reduced IgG and IgM deposits, proteinuria and mesangial hypercellularity compared with saline (P less than 0.02), but did not diminish IgA, and had no effect on mesangial matrix expansion. The combination of dextranase plus protease attenuated all components of glomerular injury as judged by clinical and pathological parameters, but inactivated dextranase plus inactivated protease had no effect on any parameter. We conclude that enzymatic digestion of antigen and antibody can reduce immune deposits, mesangial proliferation, proteinuria, and hematuria in experimental glomerulonephritis.

Animals↗
PubMed1989

Effects of platelet-derived growth factor and other polypeptide mitogens on DNA synthesis and growth of cultured rat liver fat-storing cells.

In vitro and in vivo studies suggest that liver fat-storing cells (FSC) may play an important role in the development of liver fibrosis. We explored the effects of platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor (TGF)-alpha and TGF-beta, and basic fibroblast growth factor (bFGF) on DNA synthesis and growth of rat liver FSC. PDGF, EGF, TGF-alpha, and bFGF induced a dose-dependent increase in DNA synthesis with a peak effect at 24 h. PDGF produced the most striking effect with a maximum 18-fold increase over control. EGF, TGF-alpha, and bFGF elicited a maximum three- to fourfold increase in DNA synthesis. Analysis of growth curves revealed a similar pattern of potency of the growth factors. TGF-beta did not affect DNA synthesis of FSC; however, TGF-beta markedly potentiated the stimulatory effects of both EGF and PDGF. FSC showed high specific binding of 125I-PDGF and Scatchard analysis revealed high affinity receptors with an apparent Kd of 2.3 x 10(-10) M. Our data suggest that PDGF is a key mitogen for FSC and that the coordinate release of other growth factors together with PDGF by inflammatory cells represents a potent potential stimulus for FSC proliferation in conditions of chronic self-perpetuating liver inflammation.

Animals↗