Usefulness of a New Large Set of High Throughput EST-SNP Markers as a Tool for Olive Germplasm Collection Management.

Germplasm collections are basic tools for conservation, characterization, and efficient use of olive genetic resources. The identification of the olive cultivars maintained in the collections is an important ongoing task which has been performed by both, morphological and molecular markers. In the present study, based on the sequencing results of previous genomic projects, a new set of 1,043 EST-SNP markers has been identified. In order to evaluate its discrimination capacity and utility in diversity studies, this set of markers was used in a representative number of accessions from 20 different olive growing countries and maintained at the World Olive Germplasm Collection of IFAPA Centre 'Alameda del Obispo' (Córdoba, Spain), one of the world's largest olive germplasm bank. Thus, the cultivated material included: cultivars belonging to previously defined core collections by means of SSR markers and agronomical traits, well known homonymy cases, possible redundancies previously identified in the collection, and recently introduced accessions. Marker stability was tested in repeated analyses of a selected number of accessions, as well as in different trees and accessions belonging to the same cultivar. In addition, 15 genotypes from a cross 'Picual' × 'Arbequina' cultivars from the IFAPA olive breeding program and a set of 89 wild genotypes were also included in the study. Our results indicate that, despite their relatively wide variability, the new set of EST-SNPs displayed lower levels of genetic diversity than SSRs in the set of olive core collections tested. However, the EST-SNP markers displayed consistent and reliable results from different plant material sources and plant propagation events. The EST-SNPs revealed a clear cut off between inter- and intra-cultivar variation in olive. Besides, they were able to reliably discriminate among different accessions, to detect possible homonymy cases as well as efficiently ascertain the presence of redundant germplasm in the collection. Additionally, these markers were highly transferable to the wild genotypes. These results, together with the low genotyping error rates and the easy and fully automated procedure used to get the genotyping data, validate the new set of EST-SNPs as possible markers of choice for olive cultivar identification.

The utility of yeast as a tool for cell-based, target-directed high-throughput screening.

Many Neglected Tropical Diseases (NTDs) have recently been subject of increased focus, particularly with relation to high-throughput screening (HTS) initiatives. These vital endeavours largely rely of two approaches, in vitro target-directed screening using biochemical assays or cell-based screening which takes no account of the target or targets being hit. Despite their successes both of these approaches have limitations; for example, the production of soluble protein and a lack of cellular context or the problems and expense of parasite cell culture. In addition, both can be challenging to miniaturize for ultra (u)HTS and expensive to utilize. Yeast-based systems offer a cost-effective approach to study and screen protein targets in a direct-directed manner within a eukaryotic cellular context. In this review, we examine the utility and limitations of yeast cell-based, target-directed screening. In particular we focus on the currently under-explored possibility of using such formats in uHTS screening campaigns for NTDs.

[Renal transplantation with living donors. A critical analysis of surgical procedures based on 40 years of experience]. / Transplante renal de donante vivo: un análisis crítico de estrategias quirúrgicas basado en 40 años de experiencia.

INTRODUCTION: Absolute priority in an LDKT programme are donnor safety and kidney optimal anatomical and functional preservation. Reduced donnor morbidities, both at short and long term, are important objectives. Excellent technical grafting is a must as are the strategies employed for facilitatig it. We revised the incidences of our whole LDKT programme (40 years 243 donors) to confirm if these exigences have been acomplished or a change to new surgical procedures is recommended. MATERIAL AND METHODS: Between 1968-2008 243 nephrectomies and grafting has been performed, a reduced number per year (A cadaver programme has been running simultaneously since 1964). For the nephrectomies a Turner-Warrick apprach was inititialy used and since 1973 a miniincisional, anterior, extraperitoneal approach of approximately 10 cm in length. The right kidney was removed in 75% of the cases and the right iliac area for the implant in 85% In adjacent opperating rooms, one team performs the nephrectomy while the other prepares and dissects free the grafting vessels. Most of the time the same senior surgeon performed both operatios: the nephrectomy and the implant. Peroperative and postoperative complications were evaluated by urologists and nephrologists in charge. RESULTS: No donors dead, organs lost or major complications in the donors have been documented. Minor complications such as intestinal paresia, wound infection, persistent incisional pain were common. Miniincisional abdominal approach reduced postoperative pain and hospital stay (4 days). At long term no incisional hernia or abdominal paresia have been documented. Simultaneous work reduces ischemia time (30-45 s warm: 30-45 min cold) and opperatig room occupation(patient preparation plus anesthesia plus operation) estimated in 90-120 min for the nephrectomy and 120-160 for the grafting. The responsibility of the senior surgeon in both procedures facilitates vessel selection for the grafting. CONCLUSIONS: No reasons have been found to reconvert our current nephrectomy procedure to laparoscopic or modify current surgical strategy. Superior safety of open surgery for donors and organs is confirmed. Pain and recovery time are reduced in laparoscopic surgery but not as much when compared with miniincisional approach. Open surgery permits optimal anatomical and functional organ extration facilitatig the quality of the implant. As numbers matter in laparoscopic surgery open nephrectomy is recommended for reduced LDKT programmes.

Use of the new proliferation signal inhibitor everolimus in renal transplant patients in Spain: preliminary results of the EVERODATA registry.

Everolimus (Eve) has shown good efficacy and safety profiles in clinical trials in combination with low doses of cyclosporine but there is limited experience in other modes, especially with calcineurin inhibitor elimination. We developed a retrospective study to analyze its clinical use after approval in Europe in 2005. Herein we have presented the results of a series of 272 patients followed for the first 6 months after Eve introduction. In 93.8% of cases Eve was introduced after the first month posttransplantation (conversion use), and 6 months after introduction, the CNI had been eliminated in 75% of cases. The main indication for Eve introduction was the diagnosis of a malignant neoplasm (42%), whereas the combined indication of prevention and/or treatment of toxicity, especially nephrotoxicity, accounted for 46.3% of cases. Initial doses were low (1.37 mg/d), but were progressively increased up to 2 mg/d at 6 months. Renal function remained unchanged during the follow-up period, whereas proteinuria moderately increased. Only 5 cases (2%) of acute rejection episodes were observed with excellent patient and graft survivals at 6 months after conversion. Further analysis of this extensive series of patients with a longer follow-up is needed.

Immunoprophylaxis with Simulect (basiliximab) in kidney transplantation: results from routine clinical practice at 18 kidney transplant units.

OBJECTIVE: The objective of this study is to assess a Simulect (basiliximab) regimen in routine clinical practice in the Spanish kidney transplantation units to evaluate efficacy and safety. METHODS: In this prospective, observational study, data on demographics, parameters of efficacy, and safety in patients who under with kidney transplantation treated with Simulect (basiliximab) were collected through an on-line collection system. RESULTS: One hundred sixty three patients at 18 kidney transplant units included 12 months follow-up. The patient mean age was 52 years (DS 13,67) including 96 (58.90%) men and 67 (41.10%) women. Cold ischemia time was 19 hours (DS 6,79). Only 2 patients presented with PRA >50%. For prophylactic immunosuppression, 67.13% of patients received triple therapy with CNI (cyclosporine 49.65% or tacrolimus 17.48%), MMF (66.43%) or AZA (10.49%), and steroids. Incidence of acute rejection (AR) at 12 months was 12.27% (1.84% steroid-resistant). In subgroup analysis, AR was 13.5% in nondiabetics and 4.5% in diabetics, including 3 steroid-resistant episodes (1.84%) in nondiabetics and none in diabetics. In relation to donor age, AR was incidence 10.3% in patients with kidneys from donors aged 50 years or younger and 10.6% when donors were older than 50 years, including 1 (1.73%) and 2 (1.93%) steroid-resistant episodes, respectively. The graft and patient survival rates at 12 months were 90% and 98%, respectively. CONCLUSIONS: Simulect (basiliximab) used in routine clinical practice provided good prophylaxis against acute rejection in several kidney transplant patient populations, similar to that observed in randomized clinical studies with excellent tolerability and safety.

Role of the renin-angiotensin system in vascular diseases: expanding the field.

The renin-angiotensin system (RAS) has emerged as one of the essential links in the pathophysiology of vascular disease. Angiotensin (Ang) II, the main peptide of the RAS, was considered as a vasoactive hormone, but in the past years, this view has been modified to a growth factor that regulates cell proliferation/apoptosis and fibrosis. Recently, this view has been enlarged with a novel concept: Ang II participates in the inflammatory response, acting as a proinflammatory mediator. In resident vascular cells, Ang II produces chemokines, cytokines, and adhesion molecules, which contribute to the migration of inflammatory cells into the tissue injury. Ang II is also a chemotactic and mitogenic factor for mononuclear cells. The molecular mechanisms of Ang II-induced vascular damage are mediated by the activation of transcription factors, redox signaling systems, and production of endogenous growth factors. In addition, other components of the RAS could also be involved in the pathogenesis of cardiovascular diseases. The Ang II degradation product Ang III shares some of its properties with Ang II, including chemotaxis and production of growth factors and chemokines. All these data clearly demonstrate that Ang II is a true cytokine, show the complexity of the RAS in pathological processes, and provide some mechanistic responses of the beneficial effects of the treatment with RAS blockers in cardiovascular diseases.

Angiotensin-converting enzyme is upregulated in the proximal tubules of rats with intense proteinuria.

Persistent proteinuria is considered a deleterious prognostic factor in most progressive renal diseases. However, the mechanisms by which proteinuria induces renal damage remain undetermined. Since proximal tubular cells possess all the machinery to generate angiotensin II (Ang II), we approached the hypothesis that proteinuria could elicit the renal activation of the renin-angiotensin system in a model of intense proteinuria and interstitial nephritis induced by protein overload. After uninephrectomy (UNX), Wistar-Kyoto rats received daily injections of 1 g BSA or saline for 8 days. The mean peak of proteinuria was observed at the fourth day (538+/-89 versus 3+/-1 mg/24 h in UNX controls; n=12; P<0.05) and was increased during the whole study period (at the eighth day: 438+/-49 mg/24 h; n=12; P=NS). Morphological examination of the kidneys at the end of the study showed marked tubular lesions (atrophy, vacuolization, dilation, and casts), interstitial infiltration of mononuclear cells, and mesangial expansion. In relation to UNX control rats, renal cortex of BSA-overloaded rats showed an increment in the gene expression of angiotensinogen (2.4-fold) and angiotensin-converting enzyme (ACE) (2.1-fold), as well as a diminution in renin gene expression. No changes were observed in angiotensin type 1 (AT1) receptor mRNA expression in both groups of rats. By in situ reverse transcription-polymerase chain reaction and immunohistochemistry, ACE expression (gene and protein) was mainly localized in proximal and distal tubules and in the glomeruli. By immunohistochemistry, angiotensinogen was localized only in proximal tubules, and AT1 receptor was localized mainly in proximal and distal tubules. In the tubular brush border, an increase in ACE activity was also seen (5. 5+/-0.5 versus 3.1+/-0.7 U/mg protein x10(-4) in UNX control; n=7; P<0.05). Our results show that in the kidney of rats with intense proteinuria, ACE and angiotensinogen were upregulated, while gene expression of renin was inhibited and AT1 was unmodified. On the whole, these data suggest an increase in Ang II intrarenal generation. Since Ang II can elicit renal cell growth and matrix production through the activation of AT1 receptor, this peptide may be responsible for the tubulointerstitial lesions occurring in this model. These results suggest a novel mechanism by which proteinuria may participate in the progression of renal diseases.

3-Hydroxy-3-methylglutaryl coenzyme a reductase and isoprenylation inhibitors induce apoptosis of vascular smooth muscle cells in culture.

Recent evidence suggests that apoptosis may be involved in the control of vascular smooth muscle cell (VSMC) number in atherosclerotic lesions. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been reported to induce apoptosis in a variety of tumor cell lines. To evaluate whether these agents also induce apoptosis of VSMCs, cultured rat VSMCs were treated with increasing doses of atorvastatin in the presence of FBS as a survival factor. The presence of apoptosis was evaluated by morphological criteria, annexin V binding, and DNA fragmentation and quantified as the proportion of hypodiploid cells by flow cytometry. Atorvastatin induced apoptosis in a dose-dependent manner, an effect also seen with simvastatin and lovastatin, but not with the hydrophilic drug pravastatin. The proapoptotic effect of statins was seen only when the inhibition of acetate incorporation into sterols was >95% and was fully reversed by mevalonate, farnesyl pyrophosphate, and geranylgeranyl pyrophosphate but not by isopentenyl adenosine, ubiquinone, or squalene, suggesting a role for prenylated proteins in the regulation of VSMC apoptosis. To further assess the role of protein prenylation, VSMCs were exposed to the prenyl transferase inhibitors perillic acid and manumycin A. Both agents induced VSMC apoptosis as evaluated by the above-mentioned criteria. Finally, VSMC treatment with lipophilic statins was associated with decreased prenylation of p21-Rho B, further supporting the role of protein prenylation inhibition in statin-induced VSMC apoptosis. The present data suggest that interference with protein prenylation by HMG-CoA reductase inhibitors or other agents may provide new strategies for the prevention of neointimal thickening.

Angiotensin II participates in mononuclear cell recruitment in experimental immune complex nephritis through nuclear factor-kappa B activation and monocyte chemoattractant protein-1 synthesis.

Angiotensin-converting enzyme (ACE) inhibitors reduce macrophage infiltration in several models of renal injury. We approached the hypothesis that angiotensin II (AngII) could be involved in inflammatory cell recruitment during renal damage through the synthesis of monocyte chemoattractant protein-1 (MCP-1). In a model of immune complex nephritis, we observed an up-regulation of renal MCP-1 (mRNA and protein) coincidentally with mononuclear cell infiltration that were markedly reduced by treatment with the ACE inhibitor quinapril. Exposure of cultured rat mesangial cells to AngII increased MCP-1 mRNA expression (2.7-fold) and synthesis (3-fold), similar to that observed with TNF-alpha. Since NF-kappaB is involved in the regulation of MCP-1 gene, we explored whether the effects of AngII were mediated through NF-kappaB activation. Untreated nephritic rats showed increased renal NF-kappaB activity (3.5-fold) that decreased in response to ACE inhibition. In mesangial cells, AngII activated NF-kappaB (4.3-fold), and the NF-kappaB inhibitor pyrrolidine dithiocarbamate abolished the AngII-induced NF-kappaB activation and MCP-1 gene expression. Our results suggest that AngII could participate in the recruitment of mononuclear cells through NF-kappaB activation and MCP-1 expression by renal cells. This could be a novel mechanism that might further explain the beneficial effects of ACE inhibitors in progressive renal diseases.

Overexpression of extracellular matrix proteins in renal tubulointerstitial cells by platelet-activating-factor stimulation.

BACKGROUND: One common feature of renal diseases is the development of interstitial fibrosis, but the mechanism of this process remains undefined. We hypothesized that platelet-activating factor (PAF), a classical acute inflammatory mediator involved in the pathogenesis of renal damage, acts on renal tubulointerstitial cells, contributing to the development of fibrosis. For this reason we evaluated the effect of PAF on matrix regulation and cell-growth-related events in tubulointerstitial cells. METHODS: In vitro studies were conducted with two tubulointerstitial cell lines: renal tubuloepithelial cells (NRK 52E) and interstitial fibroblasts (NRK 49F). The effect of PAF on extracellular matrix gene expression was determined by Northern blot. Fibronectin synthesis was quantified by metabolic labelling and immunoprecipitation. Cell growth changes were evaluated by fluorescence-activated cell-sorting analysis (cell cycle and size) and total protein content by 3[H]leucine incorporation. RESULTS: In renal tubuloepithelial cells and interstitial fibroblasts, PAF increased fibronectin mRNA expression. PAF-effect on the expression of collagen genes differed depending on the cell type studied. In tubuloepithelial cells there was an increase in type I and IV collagen mRNA levels, while only type I collagen was increased in fibroblasts. The overexpression of matrix proteins induced by PAF was completely blocked by preincubation of cells with the PAF receptor antagonist, BN52021. The PAF-induced upregulation of fibronectin expression was correlated with the increase in fibronectin synthesis. These effects were not associated with an increase in hyperplasia (characterized by changes in cell cycle) either in tubuloepithelial cells or in interstitial fibroblasts. Moreover, PAF did not induce tubular hypertrophy (changes in protein content and cell size). CONCLUSIONS: Our data suggest that PAF could be a mediator involved in extracellular matrix accumulation and, therefore, participate in the formation of renal interstitial fibrosis.

Endothelin-1 upregulation in the kidney of uninephrectomized spontaneously hypertensive rats and its modification by the angiotensin-converting enzyme inhibitor quinapril.

Endothelin (ET-1) is a potent vasoconstrictor that plays an important role in the control of renal circulation and tubular function. The contribution of this peptide to the pathogenesis of systemic hypertension and renal failure remains largely undefined. In spontaneously hypertensive rats (SHR) uninephrectomized at 20 weeks of age (UNX-SHR) and followed until 45 weeks of age, we determined ET-1 gene expression in renal tissue by reverse transcription-polymerase chain reaction and its localization by in situ hybridization in paraffin-embedded kidney sections. Age-matched SHR and normotensive Wistar-Kyoto (WKY) rats were chosen as controls. At the end of the follow-up, UNX-SHR had high systolic blood pressure, intense proteinuria, mesangial expansion, focal and segmental glomerular sclerosis, and tubulointerstitial lesions. In relation to WKY and SHR, UNX-SHR exhibited an increase in ET-1 gene expression in renal cortex and medulla. By in situ hybridization and immunoperoxidase staining, an overexpression of ET-1 gene and protein were seen in mesangial and glomerular epithelial cells and in some proximal tubules and vessels. Angiotensin-converting enzyme (ACE) activity was significantly increased in the renal brush border. Since in mesangial cells, angiotensin II induces ET-1 synthesis, a group of UNX-SHR received the ACE inhibitor quinapril from the time of UNX. These animals had a decrease in blood pressure, proteinuria, and serum and brush border ACE activity and in the expression and synthesis of ET-1 in all renal areas. On the whole, these data show that UNX-SHR have an upregulation of ET-1 gene and protein in several structures of the kidney compared with SHR and WKY rats. Quinapril diminished ACE activity and ET-1 expression and synthesis coincidentally with an improvement in proteinuria and morphological lesions. The beneficial effects of ACE inhibitors may be due to the diminution of both angiotensin II and ET-1 generation.

Expression of leucocyte chemoattractants by interstitial renal fibroblasts: up-regulation by drugs associated with interstitial fibrosis.

Interstitial inflammation is a strong predictor of long-term renal damage. The potential role of renal interstitial fibroblasts in recruitment of inflammatory leucocytes into the interstitium is unclear. We have thus studied the mRNA expression of several leucocyte chemotactic factors by rat renal interstitial fibroblasts and its modulation by cytokines. In addition, the effects of two unrelated drugs associated with the development of interstitial fibrosis, namely puromycin aminonucleoside (PAN) and cyclosporin A (CsA), were also studied. Rat renal interstitial fibroblasts showed constitutive mRNA expression for the chemokines monocyte chemoattractant protein 1 (MCP-1) and interferon-inducible protein 10 (IP-10). In addition, these cells also exhibited constitutive mRNA expression for cyclophilin B, an immunophilin recently found to have leucocyte chemoattractant properties. The inflammatory cytokine tumour necrosis factor-alpha up-regulated IP-10 and MCP-1 mRNA expression (10- and four-fold, respectively), but had no effect on cyclophilin B mRNA levels. IP-10 and MCP-1 produced about a four-fold increase in MCP-1 and cyclophilin B mRNA expression, but did not affect IP-10 mRNA. PAN caused an augmentation in IP-10, MCP-1 and cyclophilin B mRNA levels (12-, 9.5, and two-fold, respectively), while CsA increased only cyclophilin B mRNA in a dose-dependent manner. In conclusion, rat renal interstitial fibroblasts express mRNA for chemotactic factors and this expression is up-regulated by inflammatory cytokines, PAN and CsA. The present findings suggest that renal interstitial fibroblasts may play an active role in the recruitment of inflammatory leucocytes into the interstitium.

Effects and interactions of endothelin-1 and angiotensin II on matrix protein expression and synthesis and mesangial cell growth.

Mesangial cell growth and accumulation of extracellular matrix proteins constitute key features of progressive glomerular injury. Endothelin-1 (ET-1) and angiotensin II (Ang II), two potent vasoconstrictor agents, evoke a number of similar responses in mesangial cells. In rat mesangial cells, we compared ET-1 and Ang II effects on matrix protein production and cell proliferation as well as the potential interaction between the two hormones. When cells in 0.5% fetal calf serum were incubated for 24 hours with various concentrations of ET-1 or Ang II, both peptides stimulated, in a dose-dependent manner, fibronectin and type IV collagen mRNA expression, fibronectin synthesis, and mitogenesis. Incubation with specific receptor antagonists of both hormones demonstrated that endothelin subtype A (ETA) and angiotensin type 1 (AT1) receptors were involved. Preincubation of cells with two different protein kinase C inhibitors or with a neutralizing anti-transforming growth factor-beta antibody, but not an unrelated IgG, diminished the peptide-induced fibronectin synthesis. A dual interrelation seems to exist between ET-1 and Ang II. Thus, the AT1 receptor antagonist losartan and the angiotensin-converting enzyme inhibitors quinaprilat and captopril diminished the ET-1-mediated effects, whereas, the ETA receptor antagonist BQ-123 diminished the Ang II-induced fibronectin synthesis and mesangial cell proliferation. Our results suggest that ET-1 and Ang II stimulate matrix protein synthesis and mesangial cell mitogenesis through ETA and AT1 receptors, respectively, by complicated mechanisms, implicating protein kinase C activation, synthesis of transforming growth factor-beta, and release of one peptide by the other. These data could be important for a better understanding of the participation of vasoactive substances in the pathogenesis of glomerulosclerosis.

Urinary excretion of platelet-activating factor in human and experimental nephrosis.

BACKGROUND: Platelet-activating factor (PAF) is a phospholipid that has been implicated in the pathogenesis of glomerulonephritis and can be synthesized by glomerular cells in response to different stimuli. PAF increases glomerular permeability to proteins and urinary PAF has been determined to be of renal origin. In order to assess whether urinary PAF can be found augmented in situations of glomerular damage without glomerular leukocyte infiltration, urinary PAF was quantified in human and experimental nephrosis. METHODS: Urinary PAF was quantified by platelet bioassay and glomerular PAF by incorporation of 3H-acetate into PAF. PAF was characterized by its behaviour on thin-layer chromatography and high performance liquid chromatography and the blockade of its bioactivity by receptor antagonists. RESULTS: Urinary PAF excretion was significantly higher in patients with active idiopathic nephrotic syndrome than in controls (5.8+/-1.5 versus 1.7+/-0.75 mg/24 h; P<0.05) and patients in remission (1.63+/-0.75 ng/24 h; P<0.02). In rats with nephrosis induced by puromycin aminonucleoside there was an early increase in urinary PAF excretion (138+/-19 versus 49+/-22 pg/24 h in controls; P<0.035) that coincided with the augmented glomerular PAF synthesis (67+/-3.4 versus 36+/-1.2 DPM/mg protein in controls; P<0.003). CONCLUSIONS: These results suggest that the synthesis of PAF in the kidney may be involved in the pathogenesis of the proteinuria in idiopathic nephrotic syndrome and that urinary PAF excretion may be a good marker of disease activity.

Interferon-inducible protein-10 is highly expressed in rats with experimental nephrosis.

Interferon-inducible protein (IP)-10 is a small glycoprotein member of a family of chemotactic cytokines structurally related to interleukin-8. We have recently described the induction of IP-10 mRNA in mouse mesangial cells stimulated with lipopolysacharide, interferon-gamma, and tumor necrosis factor-alpha. To further evaluate a possible role for this chemokine in renal injury, we have studied IP-10 in an experimental model of nephrosis induced in rats by adriamycin. High levels of glomerular IP-10 mRNA expression and glomerular and tubulointerstitial IP-10 protein were seen on day 21, coinciding with maximal proteinuria, glomerular tumor necrosis factor mRNA expression, and interstitial cellular infiltrates. Maintenance on a low protein diet not only delayed the appearance of proteinuria and interstitial cellular infiltrate but also decreased glomerular IP-10 mRNA expression. Isolated normal glomeruli and cultured glomerular epithelial and mesangial cells from normal rats expressed IP-10 mRNA upon stimulation with 100 U/ml interferon or 1 microgram/ml lipopolysaccharide for 3 hours. IP-10 mRNA expression was also inducible by lipopolysaccharide and cytokines in NRK 49F renal interstitial fibroblasts and, to a lesser extent, in NRK 52E tubular epithelial cells. Furthermore, IP-10 protein was inducible in murine mesangial cells. We conclude that IP-10 is highly inducible in vitro and in vivo in resident glomerular and tubulointerstitial cells. IP-10 may participate in the modulation of renal damage in experimental nephrosis.

Cyclosporin A (CsA) modulates the glomerular production of inflammatory mediators and proteoglycans in experimental nephrosis.

Nephrosis is characterized by glomerular epithelial cell injury and a decrease in the glomerular basement membrane (GBM) proteoglycan content. Although CsA is a useful treatment for a group of patients with this disease, its mechanism of action is unclear. We have previously shown that in experimental nephrosis there is an increase in the glomerular production of tumour necrosis factor-alpha (TNF-alpha) and platelet-activating factor (PAF). Here we have studied the effect of CsA on kidney generation of TNF-alpha and PAF in puromycin aminonucleoside (PAN) nephrosis as well as on the synthesis of proteoglycans by cultured glomerular epithelial cells. Rats receiving CsA had, on day 8 of PAN injection, a significant reduction in proteinuria, blood cholesterol levels and in interstitial mononuclear cells. A diminution in glomerular production and urinary excretion of TNF-alpha and PAF was also noted. In in vitro studies, at 24 h of incubation PAF and TNF-alpha induced in glomerular epithelial cells a significant decrease in proteoglycan synthesis. Neither PAF nor TNF-alpha had any significant effect on glomerular epithelial cell proliferation. CsA alone induced a dose-response increase in proteoglycan synthesis and a slight decrease in cell proliferation. CsA also reversed the inhibitory effect of PAF and TNF-alpha on proteoglycan synthesis. However, CsA did not alter the pattern of proteoglycan production, remaining around 50% chondroitinase ABC-, 15% heparitinase-sensitive. Our results indicate that PAF and TNF-alpha could be implicated in the pathogenesis of nephrosis through the inhibition of proteoglycan synthesis by glomerular epithelial cells. The beneficial effect of CsA in nephrosis may be due to the recovery of the GBM charge selectivity caused by the normalization of glomerular PAF and TNF-alpha synthesis and the increase in proteoglycan synthesis by glomerular epithelial cells.