Early Progression of Xanthogranulomatous Pyelonephritis in Children Might Be Dependent on Vimentin Expression.

BACKGROUND Xanthogranulomatous pyelonephritis (XP) is an extremely rare, severe, atypical form of chronic renal parenchymal inflammation accompanied by hydronephrosis and/or urolithiasis. The pathomechanism of XP is not yet fully understood. Microscopically, XP is indicated by the presence of multinucleated giant cells and lipid-laden macrophages, as well as inflammatory infiltration and intensive renal fibrosis. The lipid accumulation in kidney parenchyma may be secondary to the altered flow of low-density lipoprotein (LDL)-derived cholesterol particles inside the affected cells. Physiologically, the process of LDL-derived cholesterol transport from lysosomes to the sites of its esterification is dependent on vimentin, which is a molecule comprising the cytoskeleton in mesenchymal cells. CASE REPORT A 7-year old girl was hospitalized because of the finding of unexplained kidney lesions on an abdominal ultrasound examination (an enlarged and deformed collecting system of the right kidney with hyperechogenic, solid, staghorn lesions in the calyces). Three months earlier, the patient had experienced recurrent urinary tract infection. Based on the subsequent laboratory and imaging diagnostics, the final diagnosis of XP was established and the girl was qualified for right-sided nephrectomy Microscopic examination revealed numerous foci of granuloma formations with no evident exponents of dysplastic or neoplastic abnormalities. Significant CD68-positive cell infiltrations and scattered foam cells arranging the numerous foci of granuloma inflammation were noticed. Renal parenchyma, adjacent to granuloma lesions, presented a vimentin expression. CONCLUSIONS Vimentin expression in XP may confirm a focal character of chronic granuloma formation and may suggest the complexity of XP pathogenesis involving not only macrophage and fibroblast activation but also local lipid deregulation and fibrosis.

Xanthogranulomatous pyelonephritis is associated with higher tissue expression of monocyte chemotactic protein-1.

TOPIC: Xanthogranulomatous pyelonephritis (XGP) is a chronic inflammation of the kidney characterized by destruction and replacement of its parenchyma with granulomatous tissue. It is associated with both chronic urinary obstruction and urinary tract infection (UTI). METHODS: We studied two children with chronic ureteropelvic junction obstruction (UPJO) and recurrent UTI nephrectomized for poor kidney function. An intraoperative renal biopsy was taken to relate the presence of infiltrating monocytes plus tubular atrophy to tissue expression of monocyte chemotactic protein-1 (MCP-1) and epidermal growth factor (EGF). XGP was diagnosed by a pathologist in both cases. RESULTS: MCP-1 expression was significantly higher in the two patients compared with the controls or patients with uncomplicated UPJO. It also correlated with the extent of monocyte infiltration, whereas EGF was only significantly downregulated when compared with the controls. CONCLUSIONS: MCP-1 would seem to play a key role in the pathogenesis of XGP by mediating the recruitment of circulating monocytes or by cells resident in the interstitial space.

Absence of peripheral-type benzodiazepine binding sites in renal carcinoma: a potential biochemical marker.

In an attempt to identify a tumour marker, we investigated peripheral-type benzodiazepine binding sites (PBS) in kidney specimens obtained from patients who underwent nephrectomy due to a renal mass. [3H]PK 11195, an isoquinoline carboxamide derivative, was used as a ligand. Binding assays were conducted on samples of membrane homogenate taken from both the healthy portion and the tumour site of the kidney. It was found that binding characteristics of benign tumours and normal kidney tissues were not significantly different, i.e. equilibrium dissociation constants of 2.20 +/- 0.73 and 2.38 +/- 0.98 nM, respectively, and maximal number of binding sites of 3190 +/- 1081 and 4189 +/- 998 fmol/mg protein, respectively. In contrast, no PBS were detectable in renal carcinoma. The absence of PBS in malignant renal tissues may serve as a biochemical marker for tumours of the kidney.