PubMed Health⌕ Search

Biomedical subjects

Dorella Del Prete

Publications and source records attributed to Dorella Del Prete.

9 recordsLinked to original sources
PubMed2006

Mild tubular damage induces calcium oxalate crystalluria in a model of subtle hyperoxaluria: Evidence that a second hit is necessary for renal lithogenesis.

Environment and diet have a major role in calcium nephrolithiasis by affecting urine saturation, but this is not enough to cause lithogenesis; the crystals must adhere to the tubular epithelium (TE), but it is hard to say how environment and nutrition may be involved in this step. The hypothesis that TE damage (known to enhance crystal attachment) is lithogenic in mild hyperoxaluria was tested. Mild hyperoxaluria was induced in male Wistar rats using ethylene glycol (EG; 0.5% in water) for 21 d, and TE damage was induced by intraperitoneal administration of hexachloro-1:3-butadiene (HCBD; an industrial nephrotoxin) at 10, 25, and 50 mg/kg body wt on days 7 and 14. These EG and HCBD concentrations were chosen to span from suboptimal to very low doses as far as effects on crystalluria and TE damage are concerned. Enzymuria, proteinuria, oxaluria, crystalluria, and renal pathology were investigated. All HCBD dosages induced crystalluria in mildly hyperoxaluric rats, but no intrarenal crystals were found. EG alone induced very mild hyperoxaluria but no damage to the renal tubule observable on transmission electron microscopy, and it did not cause crystalluria or intrarenal crystals. HCBD with the concomitant administration of EG caused apoptosis of the TE at the two highest dosages after the second injection. Apoptosis did not correlate with crystalluria. A TE toxin is needed for crystallogenesis to occur in borderline metabolic conditions. It may take more than just a metabolic predisposition for calcium nephrolithiasis to occur, and the second hit could come from an environmental pollutant such as HCBD.

Animals↗
PubMed2006

Perforin, Granzyme B, and fas ligand for molecular diagnosis of acute renal-allograft rejection: analyses on serial biopsies suggest methodological issues.

BACKGROUND: The Perforin-Granzyme B and Fas/Fas Ligand apoptotic mechanisms are involved in the development of acute renal rejection (AR). We describe our experience of analyzing the expression of cytotoxic T-lymphotoxins (CTL) in biopsies and peripheral blood leukocytes (PBL) for the diagnosis of AR. METHODS: We analyzed Perforin (P), Granzyme B (GB) and Fas Ligand (FL) expression in 68 renal biopsies and 64 PBL using comparative kinetic RT-PCR and, for GAPDH and FL, we also replicated with real-time RT-PCR. The levels of expression were measured in different groups, such as T0 (biopsies before reperfusion and PBL in recipient before the transplant [Tx]), Td (biopsies and PBL collected for clinical purposes) and Tp (biopsies and PBL two months after Tx). RESULTS: A higher CTL expression was seen in non-rejecting (NR) biopsies in the first 2 months after Tx. P and FL were significantly more expressed during AR in all biopsies and in Td, while P remained upregulated in Tp. In PBL, there was no significant increase in CTL transcription during AR. A variable expression of CTL emerged in all T0 biopsies. CONCLUSIONS: Two lytic pathways are activated in biopsies when AR occurs shortly after Tx, whereas the P/GB mechanism prevails if it occurs later on. Only P and FL in biopsies might be able to predict AR diagnosis, but with a considerable variability in each sample, possibly due to the small portion of tissue core, which may be inadequate for molecular diagnosis. CTL expression in PBL does not correlate with histological AR.

Acute Disease↗
PubMed2006

TGFbeta1 induces epithelial-mesenchymal transition, but not myofibroblast transdifferentiation of human kidney tubular epithelial cells in primary culture.

The origin and fate of renal interstitial myofibroblasts (MFs), the effector cells of renal fibrosis, are still debated. Experimental evidence suggests that renal MFs derive from tubular epithelial cells throughout the epithelial-mesenchymal transition (EMT) process. Primary human tubular epithelial cells (HUTECs) were cultured for 4 and 6 days on plastic or type I collagen-coated plates with 1, 5, 10 and 50 ng/ml of transforming growth factor beta1 (TGFbeta1). The EMT process was monitored by morphology and immunophenotyping for alphaSMA, cytokeratin 8-18, E-cadherin, vimentin and collagen III. Quantitative comparative RT/PCR and real-time PCR were used to evaluate the expression of collagen III and IV, fibronectin, tenascin, MMP-2, CTGF, E-cadherin and cadherin 11 genes, as well as those of the Smad signalling pathway. TGFbeta1 was found capable of reactivating the mesenchymal programme switched off during tubulogenesis, but it induced no de novo expression of alphaSMA gene or myofibroblast phenotype. We demonstrate that the EMT process is conditioned by the extracellular matrix and characterized by TGFbeta1-driven Smad3 downregulation. Our study results suggest that TGFbeta1 could function as a classic embryonal inducer, initiating a cascade of de-differentiating events that might be further controlled by other factors in the cellular environment.

Actins↗
PubMed2004

Quantitave and qualitative changes in vascular endothelial growth factor gene expression in glomeruli of patients with type 2 diabetes.

OBJECTIVE: Vascular endothelial growth factor (VEGF) exists in three main splice variants, characterized by 121, 165 and 189 amino acids (VEGF 121, VEGF 165 and VEGF 189) and acts via two specific receptors: VEGF-R1 or Flt-1 and VEGF-R2 or KDR. VEGF plays an important role in the pathogenesis of diabetic retinopathy. This study examined the relationship between VEGF and its isoforms and the severity of diabetic nephropathy in type 2 diabetes. DESIGN: We evaluated the glomerular gene expression of VEGF and its receptors and studied the relationships with renal functional and structural parameters in type 2 diabetic patients. METHODS: Glomeruli from 17 kidney biopsies were microdissected; 14 out of 17 biopsies were also subjected to electron microscopic morphometric analysis to estimate glomerular structural parameters. VEGF mRNA was studied by comparative kinetic RT-PCR and real-time RT-PCR in order to identify the three different isoforms and to quantify VEGF, VEGF-R1 and VEGF-R2 mRNA levels. RESULTS: (i) Glomerular VEGF mRNA levels were inversely related to albumin excretion rate (r=-0.66, P=0.004); (ii) both the degree of mesangial and mesangial matrix expansion were inversely related to VEGF 165 mRNA levels (r=-0.73, P=0.005 and r=-0.64, P=0.017), and directly to VEGF 121 mRNA levels (r=0.74, P=0.003 and r=0.73, P=0.004); and (iii) VEGF and VEGF-R2 mRNA levels were directly related (r=0.62, P=0.033). CONCLUSIONS: These findings suggested that quantitative and qualitative changes in VEGF expression are present in type 2 diabetic patients with nephropathy and might be involved in the pathogenesis and progression of diabetic glomerulopathy.

Aged↗
PubMed2003

Precocious activation of genes of the renin-angiotensin system and the fibrogenic cascade in IgA glomerulonephritis.

BACKGROUND: The renin-angiotensin system (RAS) seems to play a pivotal role in progression of immunoglobulin A (IgA) nephropathy (IgAN). Accordingly, in patients with IgAN a relationship between the RAS and the fibrogenic cascade triggered by transforming growth factor-beta1 (TGF-beta1) should be observed. This study was carried out to obtain deeper insight into the regulation of RAS and the interaction with TGF-beta1 in the diseased kidney. METHODS: Twenty renal biopsies from IgAN patients and five from renal cancer patients (controls) were analyzed in both microdissected glomerular and tubulointerstitial compartments by reverse transcription-polymerase chain reaction (RT-PCR). All patients had normal renal function. The expression of the following genes was determined: angiotensinogen (Agtg), renin, angiotensin-converting enzyme (ACE), angiotensin II (Ang II) type 1 and type II (AT1 and AT2 receptors), TGF-beta1, collagen IV (Coll IV), alpha-smooth muscle actin (alpha-SMA). Quantitative data were confirmed for TGF-beta1 and ACE genes by real-time PCR. Results. RAS genes were overexpressed in IgAN patients vs. control subjects. There was no difference between glomerular and tubulointerstitial RAS gene expression levels. On the contrary, the overactivation of fibrogenic cascade genes (TGF-beta1, Coll IV, alpha-SMA) in the tubulointerstitium was observed (TGF-beta1, glomerular 0.14 +/- 0.10 SD; tubulointerstial 0.34 +/- 0.20; P = 0.000) (alpha-SMA, glomerular 0.08 +/- 0.07; tubulointerstitial 0.35 +/- 0.19; P = 0.000) (Coll IV, glomerular 0.12 +/- 0.11; tubulointerstitial 0.22 +/- 0.10; P = 0.03). This fibrogenic cascade seems to be triggered by RAS as indicated by statistically significant correlations between the expression of their respective genes. A direct relationship between the putative Ang II activity and the expression of AT receptor genes was found in the tubulointerstitium, whereas in the glomeruli this relationship was negative. In the interstitium, statistically significant positive relationships emerged between interstitial infiltrates and the gene expression of Agtg, AT1 receptor, Coll IV, and TGF-beta1. CONCLUSION: This study demonstrates that a tight regulation of the intrarenal RAS exists in IgAN and that it follows the general rules disclosed in animal models. Moreover, the RAS seems to be activated early in the diseased kidney and it appears that such activation drives inflammation and a parallel stimulation of the TGF-beta fibrogenic loop, particularly at the tubulointerstitial level.

Adult↗
PubMedDate not supplied

Heparin reduces glomerular infiltration and TGF-beta protein expression by macrophages in puromycin glomerulosclerosis.

BACKGROUND: In a number of experimental models of nephropathy, heparin is renoprotective because it inhibits mesangial matrix synthesis and cell proliferation; in most of these models, glomerular macrophage infiltration has a pathogenic role. We investigated the hypothesis that heparin might also be renoprotective by modulating the macrophages in various ways in the chronic puromycin glomerulosclerosis model. METHODS: We studied the effect of a 3 month course, two different dosages of a non-anticoagulant heparin by immunohistochemical evaluation of the number of macrophages (ED-1 positive cells) in glomeruli, as well as the expression and deposition of TGF-beta and latent TGF-beta binding protein in foam cells and mesangial matrix. RESULTS: The renoprotective effect of heparin in this model was confirmed by our observation of lower urine protein and albumin excretion, and a reduced glomerular sclerosis score. These effects were associated with the prevention of macrophage glomerular infiltration, and the inhibition of the TGF-beta axes in foam cells as shown by the reduction in cytoplasm immunostaining for TGF-beta and LTBP-1; heparin also reduced peri-macrophagic collagen IV deposition. CONCLUSIONS: The inhibition of TGF-beta in macrophages seems to be part of heparin general activities. The inhibitory effect of heparin on macrophage infiltration and TGF-beta synthesis in this renal disease model supports the notion that heparin and derived molecules constitute potentially useful therapeutic agents in nephropathies.

Analysis of Variance↗
PubMedDate not supplied

Is the simian virus SV40 associated with idiopathic focal segmental glomerulosclerosis in humans?

BACKGROUND: Glomerulosclerosis was reported in mice transgenic for the simian polyomavirus SV40 early region that contains the transforming sequences encoding the SV40 large T-antigen (TAG). This was discovered when an SV40 epidemic occurred following the use of contaminated polio vaccines during 1955-1963, and led to investigations that showed an association between SV40 infection and tumors in humans. We investigated the possible association of SV40 infection and idiopathic focal segmental glomerulosclerosis (FSGS). METHODS: The study was performed in 17 Bouin-fixed, paraffin-embedded renal biopsies from FSGS patients and 10 matched biopsies from patients with IgA glomerulonephritis; all patients had undergone polio vaccination in the early 1960s. Extracted DNA was polymerase chain reaction (PCR) amplified using SV.for3/SV.rev primers and GabE1/GabE2 primers; both sets of primers map in the region of SV40 TAG sequences, and amplify a fragment of respectively 105-bp and 135-bp. The biopsies considered were those in which the DNA was sufficiently intact to allow amplification of a fragment of 102-bp of the ApoE gene. RESULTS: Three FSGS and none of the IgA biopsies were positive for the SV.for3/SV.rev fragment. Conversely, amplification with GabE1/GabE2 primers did not lead to any specific product in either the IgA or FSGS biopsies. Restriction fragment length polymorphism and sequencing analyses revealed that the positive results obtained with the SV.for3/SV.rev primers were due to amplicons generated by multiple dimerization of forward and reverse primers. CONCLUSIONS: With the limited number of patients investigated, this study excludes the hypothesis that SV40 is associated with idiopathic FSGS.

Antigens, Polyomavirus Transforming↗