RESUMEN
Glomerular fibrillary deposits have occasionally been reported in diabetic nephropathy, but no large-scale, ultrastructural evaluation of these deposits has been reported so far. Here, we report our study of glomerular non-Congophilic, DnaJ homolog subfamily B member 9 negative fibrillary deposits in diabetic nephropathy as characterized by transmission electron microscopy. Clinical data from 55 patients with biopsy-confirmed diabetic nephropathy and 18 healthy living donors were reviewed, and their biopsies were evaluated by light microscopy, immunofluorescence, and electron microscopy. Small fibrillary structures with a diameter of 10 ± 1 nm were present in all cases with diabetic nephropathy, regardless of the histologic class. In addition, glomerular fibrillary structures with a diameter of 23 ± 5 nm or 30 ± 7 nm were present in 35 cases. Interestingly, especially the small- and medium-sized fibrils, usually without apparent organization, were comparable with fibrils in fibrillary glomerulopathy. We conclude that glomerular fibrillary deposits occur far more commonly in renal biopsies of patients with diabetic nephropathy than generally considered. This is an important finding because their similarity to fibrils in fibrillary glomerulonephritis may complicate the histologic diagnostic process, especially in cases of overlapping clinical manifestations. Therefore, when encountering fibrillary deposits on electron microscopy, it is important to consider diabetic nephropathy as an alternative diagnosis.
Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Glomerulonefritis , Humanos , Nefropatías Diabéticas/patología , Glomérulos Renales/patología , Microscopía Electrónica , Microscopía Electrónica de TransmisiónRESUMEN
Proteinuria has been identified as prognosticator of renal outcome in patients with ANCA-associated glomerulonephritis, but whether proteinuria is related to podocyte abnormalities in these patients is largely unknown. We here investigate podocyte foot process width and number of podocytes positive for the podocyte marker WT-1 in diagnostic renal biopsies of 25 Caucasian patients with ANCA-associated glomerulonephritis in relation to proteinuria. Control tissue was used from pre-transplantation donor kidney biopsies. Proteinuria at 10 weeks follow-up correlated significantly with foot process width (P = 0.04). Biopsies with foot process width ≥600 nm belonged more often to the crescentic or mixed class, whereas biopsies with a foot process width <600 nm were most often categorized as focal class (P = 0.03). The mean number of podocytes based upon expression of WT-1 was significantly lower in patients compared to controls (15 vs. 34 podocytes per glomerulus; P < 0.0001). The significant decrease in expression of the podocyte WT-1 marker in ANCA-associated glomerulonephritis is considered indicative of actual podocyte loss or at least, of a loss of functionality. Furthermore, our study indicates that podocyte foot process width at baseline could be indicative for proteinuria at short term follow up. For prognostic purposes, we therefore suggest to include a description of the foot process width in the diagnostic report of a biopsy with ANCA-associated glomerulonephritis.
Asunto(s)
Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Podocitos/inmunología , Proteinuria/inmunología , Adulto , Anciano , Biopsia , Estudios de Casos y Controles , Femenino , Glomerulonefritis/patología , Glomerulonefritis/cirugía , Humanos , Trasplante de Riñón , Masculino , Persona de Mediana Edad , Podocitos/patología , Proteinuria/patología , Proteinuria/cirugíaRESUMEN
Cyclodextrins can increase the apparent solubility and dissolution rate of poorly water-soluble drug candidates improving their biopharmaceutical performance. The current data assess the ability of hydrophilic cyclodextrins to solubilize compounds via stabilization of supersaturated drug solutions presumably by inhibition of nucleation and arresting crystal growth. To these points, the effects of 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) and sulfobutylether-beta-cyclodextrin (SBEbetaCD) on equilibrium solubility was assessed via phase-solubility analysis as were the interactions of these excipients on drug solubility under conditions favoring supersaturation. Phase-solubility analysis indicated that different profiles were generated as a function of the cyclodextrin examined and the pH of the complexing medium. When kinetic solubility measurements were completed, the cyclodextrins were found to stabilize concentrations of itraconazole significantly in excess of their equilibrium solubility when supersaturated solutions were formed using the co-solvent/solvent quench approach. These solutions were stable over 240 min falling in concentration at the 24 h time point of the experiment unlike those formed using surfactants and other polymers which demonstrated a rapid decrease in concentration over time. These data suggest that hydrophilic cyclodextrins might be useful formulation adjuncts in supersaturating drug delivery systems.
Asunto(s)
Excipientes/química , Itraconazol/química , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Algoritmos , Micelas , Solubilidad , Soluciones , Tensoactivos/químicaRESUMEN
Phase-solubility techniques were used to assess the effect of pH on itraconazole complexation with 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). In addition, molecular modeling using beta-cyclodextrin as a surrogate for HPbetaCD was completed. Data suggested A(p)-type solubility relationships, indicating higher order complexation at higher HPbetaCD concentrations. Stability constants were derived from the solubility isotherms using a simplex optimization procedure. At pH 2 (2 units below the pK(a4)), a 1:2 complex formation was observed, whereas at pH 4 (i.e., the pK(a4) for itraconazole) and at pH 7, 1:3 complexation occurred. The lower order of complexation observed at lower pH may be related to substructure protonation which reduced HPbetaCD interaction. Molecular mechanics also suggest 1:3 complex formation for the neutral species, indicating that possible interaction sites may include (in order of binding) triazole > 1,4-diaminophenyl > 2-butyl approximate, equals piperazine.