Resorption of immune deposits in membranous lupus nephritis following rituximab vs conventional immunosuppressive treatment.

OBJECTIVES: Studies on repeat renal biopsies in membranous LN (MLN) are limited, and evaluation of treatment response is mainly based on proteinuria. EM of renal biopsies from rituximab (RTX)-treated MLN patients has revealed resorption of sub-epithelial ICs. Whether resorption phenomena are useful for treatment evaluation, or differs between treatment regimens is not known. We studied EM findings and clinical treatment response in MLN patients after RTX vs conventional immunosuppressive treatment. METHODS: Twenty-four patients with MLN and renal biopsies performed before and after treatment were included in this retrospective observational study. Laboratory data were collected at both biopsy occasions. Seven patients had received RTX and 17 had received conventional treatment (CYC, MMF or AZA). Electron micrographs of renal tissue were scored using an arbitrary scale (0-3) for the level of sub-epithelial ICs, resorption of ICs and podocyte fusion. RESULTS: Sub-epithelial ICs decreased after treatment, however not significantly and with no difference between treatments. The resorption phenomena increased after RTX (P = 0.028), but not after conventional therapy (P = 0.29). Six out of seven (86%) RTX-treated patients had increased resorption vs 7/17 (41%) after conventional therapies (P = 0.047). Clinical responders had more pronounced resorption of ICs vs non-responders (P = 0.022). CONCLUSIONS: We report increased resorption of ICs in repeat renal biopsies in MLN, especially after RTX treatment. Increased resorption phenomena were associated with clinical response, suggesting that EM findings may be useful for treatment evaluation in MLN. Although of limited size, the study indicates that RTX is effective both clinically and at a tissue level.

Reducing VEGF-B Signaling Ameliorates Renal Lipotoxicity and Protects against Diabetic Kidney Disease.

Diabetic kidney disease (DKD) is the most common cause of severe renal disease, and few treatment options are available today that prevent the progressive loss of renal function. DKD is characterized by altered glomerular filtration and proteinuria. A common observation in DKD is the presence of renal steatosis, but the mechanism(s) underlying this observation and to what extent they contribute to disease progression are unknown. Vascular endothelial growth factor B (VEGF-B) controls muscle lipid accumulation through regulation of endothelial fatty acid transport. Here, we demonstrate in experimental mouse models of DKD that renal VEGF-B expression correlates with the severity of disease. Inhibiting VEGF-B signaling in DKD mouse models reduces renal lipotoxicity, re-sensitizes podocytes to insulin signaling, inhibits the development of DKD-associated pathologies, and prevents renal dysfunction. Further, we show that elevated VEGF-B levels are found in patients with DKD, suggesting that VEGF-B antagonism represents a novel approach to treat DKD.

Antiphospholipid Antibodies in Lupus Nephritis.

Lupus nephritis (LN) is a major manifestation of systemic lupus erythematosus (SLE). It remains unclear whether antiphospholipid antibodies (aPL) alter the course of LN. We thus investigated the impact of aPL on short-term and long-term renal outcomes in patients with LN. We assessed levels of aPL cross-sectionally in SLE patients diagnosed with (n = 204) or without (n = 294) LN, and prospectively in 64 patients with active biopsy-proven LN (52 proliferative, 12 membranous), before and after induction treatment (short-term outcomes). Long-term renal outcome in the prospective LN cohort was determined by the estimated glomerular filtration rate (eGFR) and the Chronic Kidney Disease (CKD) stage, after a median follow-up of 11.3 years (range: 3.3-18.8). Cross-sectional analysis revealed no association between LN and IgG/IgM anticardiolipin or anti-ß2-glycoprotein I antibodies, or lupus anticoagulant. Both aPL positivity and levels were similar in patients with active LN and non-renal SLE. Following induction treatment for LN, serum IgG/IgM aPL levels decreased in responders (p<0.005 for all), but not in non-responders. Both at active LN and post-treatment, patients with IgG, but not IgM, aPL had higher creatinine levels compared with patients without IgG aPL. Neither aPL positivity nor levels were associated with changes in eGFR from either baseline or post-treatment through long-term follow-up. Moreover, aPL positivity and levels both at baseline and post-treatment were similar in patients with a CKD stage ≥3 versus 1-2 at the last follow-up. In conclusion, neither aPL positivity nor levels were found to be associated with the occurrence of LN in SLE patients. However, IgG aPL positivity in LN patients was associated with a short-term impairment of the renal function while no effect on long-term renal outcome was observed. Furthermore, IgG and IgM aPL levels decreased following induction treatment only in responders, indicating that aPL levels are affected by immunosuppressive drugs in a response-dependent manner.

Histological antiphospholipid-associated nephropathy versus lupus nephritis in patients with systemic lupus erythematosus: an observational cross-sectional study with longitudinal follow-up.

INTRODUCTION: Renal involvement is a severe complication in systemic lupus erythematosus (SLE). Moreover, a subset of SLE patients develop the anti-phospholipid syndrome (APS), characterised by the occurrence of anti-phospholipid antibodies in combination with macro- and microvascular thrombotic manifestations, including acute and chronic antiphospholipid-associated nephropathy (APLN). Clinical presentations of lupus nephritis and APLN are similar and a renal biopsy is necessary to differentiate between the conditions. Our aim with this study was to investigate the occurrence of histopathological findings consistent with APLN (hAPLN) in renal biopsies from SLE patients and to investigate associations with anti-phospholipid antibody specificities, clinical manifestations, HLA-DRB1 alleles, and long-term renal outcome. METHOD: Consecutive renal biopsies from 112 SLE patients with renal involvement were investigated and evaluated for findings of hAPLN; in all there were 236 renal biopsies. Data from biopsy reports and clinical information were collected. Autoantibodies against cardiolipin and ß2-glycoprotein-1 were measured by enzyme-linked immunosorbent assay. A lupus anticoagulant test was determined with a modified Dilute Russel Viper Venom method. HLA genotyping was performed by sequence-specific primer PCR. Renal outcome was determined at study end. RESULTS: The prevalence of hAPLN was 14.3% among SLE patients with renal involvement. Compared to patients with pure lupus nephritis, occurrence of hAPLN was associated with intima changes (odds ratio (OR) = 24; 95% confidence interval (CI), 3.0 to 189.8; P < 0.0001), hypertensive vascular changes (OR = 7.8; 95% CI, 1.6 to 39.4; P = 0.01), inflammatory infiltrates (OR = 6.5; 95% CI, 1.7 to 25.1; P = 0.007) and tubular atrophy (OR = 13.1; 95% CI, 1.7 to 103.6; P = 0.002). hAPLN was associated with the presence of cardiolipin antibodies (OR = 3.3; 95% CI, 1.0 to 10.8; P = 0.05) and triple anti-phospholipid antibody positivity (OR = 4.2; 95% CI, 1.3 to 13.7; P = 0.02). Patients with hAPLN were more hypertensive (OR = 3.8; 95% CI, 1.2 to 12.3; P = 0.03) and had higher levels of creatinine as compared to lupus nephritis patients (median 116 versus 75 µmol/L; P < 0.0001). We found significantly higher frequency of HLA-DRB1*13 (OR = 5.1; 95% CI, 1.7 to 15.4; P = 0.03) and development of end-stage renal disease (OR = 5.8; 95% CI, 1.7 to 19.7; P = 0.008) in hAPLN compared with lupus nephritis. CONCLUSION: hAPLN is a severe and often unrecognized condition in SLE patients with renal involvement. We have demonstrated an increased risk for development of renal impairment and a genetic predisposition in hAPLN patients compared to lupus nephritis patients.

Evaluation of B lymphocyte stimulator and a proliferation inducing ligand as candidate biomarkers in lupus nephritis based on clinical and histopathological outcome following induction therapy.

OBJECTIVES: Lupus nephritis (LN) is a major cause of morbidity in patients with systemic lupus erythematosus (SLE). B cells have a central role in the pathogenesis of SLE. B lymphocyte stimulator (BLyS) and a proliferation inducing ligand (APRIL) are pivotal in B cell homeostasis. We aimed to investigate a potential role of serum BLyS and APRIL as biomarkers in LN, especially as predictors of treatment response. METHODS: Sixty-four patients with active LN (52 proliferative lupus nephritis (PLN); 12 membranous LN) were included. Renal biopsies were performed at baseline and after immunosuppressive treatment. Serum levels of BLyS, APRIL and autoantibodies were measured on both biopsy occasions and in 64 individually matched controls. Renal biopsies were evaluated using the International Society of Nephrology/Renal Pathology Society classification, and scored for Activity Index and Chronicity Index. Clinical responders (CR) were required to have ≥50% reduction in proteinuria, normal or improved renal function, and inactive urinary sediment. Histopathological responders (HR) were required to have ≥50% improvement in Activity Index. RESULTS: Baseline BLyS levels were significantly higher in LN patients compared with controls (p<0.001) and remained unchanged following induction treatment. APRIL levels were significantly higher in patients compared with controls at baseline (p=0.005) and decreased following treatment (p<0.001). Among PLN patients, APRIL levels decreased significantly only in responders (CR: p=0.009; HR: p=0.01). Baseline BLyS levels <1.5 ng/mL predicted treatment response, attaining a positive predictive value of 92% for CR with PLN at baseline. CONCLUSIONS: BLyS and APRIL were affected differently by immunosuppression; BLyS levels remained unchanged following therapy while APRIL levels decreased. Despite unchanged BLyS levels following therapy, low baseline levels predicted both clinical and histopathological improvement. Our data support APRIL as a candidate biomarker of renal disease activity in lupus patients with proliferative glomerulonephritis and point to low baseline BLyS levels predicting treatment response in LN, especially in PLN.

Fabry disease simulating Crohn's ileitis.

Fabry disease is an inherited (X-linked) lysosomal storage disorder caused by deficiency of α-galactosidase A, leading to accumulation of globotriaosylceramide in various tissues. A 57-year-old male with a family history and laboratory findings of Fabry disease, was consulted for severe abdominal pain, undulating pyrexia, weight loss and diarrhea. The tentative clinical diagnosis of Crohn's ileitis was supported at computed tomographic examination, at laparotomy and at inspection of the resected ileal segment. Histology revealed chronic and acute inflammation, thick-walled occluded vessels, fibrosis and characteristic bi-refringent lamellar deposits of globotriaosylceramide and calcifications. Multi-nucleated giant cells contained phagocytized bi-refringent material. Transmission electron microscopy showed cells with irregular cytoplasmic bodies displaying distinctive zebra-like lamellar structures. It is submitted that the gastrointestinal phenotype of Fabry disease may concur with symptoms resembling abdominal Crohn's disease.

Increased risk of IgA nephropathy among individuals with celiac disease.

GOAL: To determine the risk of future biopsy-verified IgA nephropathy (IgAN) among individuals with biopsy-verified celiac disease (CD). BACKGROUND: Individuals with CD suffer increased risk of end-stage renal disease. An association between CD and IgAN has been suggested; however, results have been inconclusive and no previous study has considered the risk of IgAN in biopsy-verified CD. STUDY: We performed a population-based prospective cohort study. We identified 27,160 individuals with CD (Marsh stage III) and no previous renal disease through small-intestinal biopsy reports obtained between July 1969 and February 2008 in all (n=28) Swedish pathology departments. Individuals with IgAN were identified by biopsy reports acquired at the 4 Swedish pathology departments specialized in renal pathology. Cox regression analysis was used to determine the risk of future IgAN among individuals with CD compared with 133,949 age-matched and sex-matched reference individuals. RESULTS: Seven (0.026%) individuals with CD and 11 (0.008%) reference individuals developed IgAN. We found an increased risk of biopsy-verified IgAN among individuals with CD [hazard ratio, 3.03; 95% confidence interval, 1.22-7.56]. The risk increase remained statistically significant after adjustment for prior liver disease and country of birth. CONCLUSIONS: Individuals with CD suffer a 3-fold increased risk of future IgAN. Our findings warrant awareness of renal function in individuals with CD.

Long-term follow-up in lupus nephritis patients treated with rituximab--clinical and histopathological response.

OBJECTIVE: To investigate the long-term clinical, histological and serological affects of B-cell-depleting therapy (BCDT) in patients with LN refractory to conventional treatment. METHODS: Twenty-five patients, followed for a mean time of 36 months (9-95 months), were included. Renal disease activity was evaluated with the BILAG index and renal response was determined according to the LN European consensus statement. Renal biopsies were performed for histological evaluation at baseline and follow-up. RESULTS: Partial response (PR) or complete renal response (CR) was observed in 22 of 25 after a median of 12 months. Sixteen patients achieved CR after a median of 24 months. Six patients experienced a renal relapse. Proteinuria decreased significantly (P = 0.0002) from baseline to 36 months. A noteworthy histological improvement was seen in nearly all patients with a significant reduction in activity index (P = 0.01). Longer depletion time and low baseline values of IgM were indicative of achieving clinical remission during the first year after treatment (P = 0.03 and P = 0.04, respectively). CONCLUSION: In therapy-resistant LN, BCDT induced clinical and histological improvements in the majority of patients. Transition from PR to CR was mainly seen during the second year of follow-up. Patients with longer depletion time and low baseline levels of IgM were more likely to gain a faster remission, suggesting that the clinical benefit may be linked to suppression of autoreactive plasmablasts. Although formal evidence of BCDT in LN is lacking, our data may provide guidance to clinicians considering therapeutic options in patients with refractory LN.

Renal phenotypic investigations of megalin-deficient patients: novel insights into tubular proteinuria and albumin filtration.

BACKGROUND: The reabsorption of filtered plasma proteins, hormones and vitamins by the renal proximal tubules is vital for body homeostasis. Studies of megalin-deficient mice suggest that the large multi-ligand endocytic receptor megalin plays an essential role in this process. In humans, dysfunctional megalin causes the extremely rare Donnai-Barrow/Facio-Oculo-Acustico-Renal (DB/FOAR) syndrome characterized by a characteristic and multifaceted phenotype including low-molecular-weight proteinuria. In this study, we examined the role of megalin for tubular protein reabsorption in humans through analysis of proximal tubular function in megalin-deficient patients. METHODS: Direct sequencing of the megalin-encoding gene (LRP2) was performed in a family in which three children presented with classical DB/FOAR manifestations. Renal consequences of megalin deficiency were investigated through immunohistochemical analyses of renal biopsy material and immunoblotting of urine samples. RESULTS: In the patients, a characteristic urinary protein profile with increased urinary excretion of vitamin D-binding protein, retinol-binding protein and albumin was associated with absence of, or reduced, proximal tubular endocytic uptake as shown by renal immunohistochemistry. In the absence of tubular uptake, urinary albumin excretion was in the micro-albuminuric range suggesting that limited amounts of albumin are filtered in human glomeruli. CONCLUSIONS: This study demonstrated that megalin plays an essential role for human proximal tubular protein reabsorption and suggests that only limited amounts of albumin is normally filtered in the human glomeruli. Finally, we propose that the characteristic urinary protein profile of DB/FOAR patients may be utilized as a diagnostic marker of megalin dysfunction.

Renal expression and serum levels of high mobility group box 1 protein in lupus nephritis.

INTRODUCTION: High mobility group box 1 protein (HMGB1) is a nuclear DNA binding protein acting as a pro-inflammatory mediator following extracellular release. HMGB1 has been increasingly recognized as a pathogenic mediator in several inflammatory diseases. Elevated serum levels of HMGB1 have been detected in autoimmune diseases including Systemic lupus erythematosus (SLE). However, the local expression of HMGB1 in active lupus nephritis (LN) is not known. Here we aimed to study both tissue expression and serum levels of HMGB1 in LN patients with active disease and after induction therapy. METHODS: Thirty-five patients with active LN were included. Renal biopsies were performed at baseline and after standard induction therapy; corticosteroids combined with immunosuppressive drugs. The biopsies were evaluated according to the World Health Organization (WHO) classification and renal disease activity was estimated using the British Isles lupus assessment group (BILAG) index. Serum levels of HMGB1 were analysed by western blot. HMGB1 expression in renal tissue was assessed by immunohistochemistry at baseline and follow-up biopsies in 25 patients. RESULTS: Baseline biopsies showed WHO class III, IV or V and all patients had high renal disease activity (BILAG A/B). Follow-up biopsies showed WHO I to II (n = 14), III (n = 6), IV (n = 3) or V (n = 12), and 15/35 patients were regarded as renal responders (BILAG C/D).At baseline HMGB1 was significantly elevated in serum compared to healthy controls (P < 0.0001). In all patients, serum levels decreased only slightly; however, in patients with baseline WHO class IV a significant decrease was observed (P = 0.03). Immunostaining revealed a pronounced extranuclear HMGB1 expression predominantly outlining the glomerular endothelium and in the mesangium. There was no clear difference in HMGB1 expression comparing baseline and follow-up biopsies or any apparent association to histopathological classification or clinical outcome. CONCLUSIONS: Renal tissue expression and serum levels of HMGB1 were increased in LN. The lack of decrease of HMGB1 in serum and tissue after immunosuppressive therapy in the current study may reflect persistent inflammatory activity. This study clearly indicates a role for HMGB1 in LN.

Soluble interleukin-2 receptor alfa predicts renal outcome in IgA nephropathy.

BACKGROUND: Both systemic and mucosal IgA production are controlled by T lymphocytes and infiltrating T lymphocytes are involved in the progression of interstitial fibrosis in chronic kidney disease (CKD). Since the concentration of soluble interleukin-2 receptor alfa (sIL-2Ra) reflects the degree of T cell activation over time, we studied the impact of interleukin-2 receptor alfa levels on disease progression in patients with biopsy-proven IgA nephropathy (IgAN), a disease in which 20-30% of the patients progress to end-stage renal failure. METHODS: sIL-2Ra plasma levels were measured in 194 patients (median age 39 years, 70% men) and 84 matched controls. One hundred and seventy-nine of the patients, with an estimated glomerular filtration rate (GFR) of ≥15 mL/min/1.73m(2) at baseline (CKD Stages 1-4), were followed for up to 15 years (median 52 months; range 12-188). sIL-2Ra was evaluated as a risk marker for severe renal progression, here defined by the development of CKD Stage 5 (GFR <15 mL/min/1.73m(2)), a 50% decline in GFR during the follow-up period or a 30% GFR decline within 5 years of follow-up. In 51 patients, upon whom a renal biopsy had been performed within 2 years of IL2-Ra measurement, the biopsies were scored according to the Oxford classification. The correlations between the histopathological findings and the sIL-2Ra levels were examined. RESULTS: sIL2-Ra levels were significantly higher in patients than in controls (P < 0.001). sIL-2Ra levels in the upper third tertile predicted a severe renal outcome, even after adjustment for the main clinical risk factors: time average albuminuria and GFR at baseline (Relative risk 5.35, P < 0.001). sIL-2Ra levels also correlated significantly to the yearly GFR slope (ß = -0.24, P = 0.01). According to the Oxford classification, the presence of >25% tubular atrophy/interstitial fibrosis (T1-2) was associated with higher sIL-2Ra levels, after adjustment for serum creatinine levels, if analysed within 4 months [n = 24, odds ratio (OR) 1.0, P = 0.044] or within 2 years from the kidney biopsy (n = 51, OR 1.0, P = 0.017). CONCLUSIONS: The plasma levels of sIL-2Ra were predictive of long-term renal disease progression in a large cohort of patients with biopsy-proven IgAN. Further studies are warranted to evaluate if sIL-2Ra levels can feasibly contribute in the monitoring of effects of treatment, aimed to prevent the progression of interstitial fibrosis and progressive glomerulosclerosis in IgAN.

Loss of the lupus autoantigen Ro52/Trim21 induces tissue inflammation and systemic autoimmunity by disregulating the IL-23-Th17 pathway.

Ro52/Trim21 is targeted as an autoantigen in systemic lupus erythematosus and Sjögren's syndrome. Polymorphisms in the Ro52 gene have been linked to these autoimmune conditions, but the molecular mechanism by which Ro52 may promote development of systemic autoimmune diseases has not been explored. To address this issue, we generated Ro52-null mice (Ro52(-/-)), which appear phenotypically normal if left unmanipulated. However, Ro52(-/-) mice develop severe dermatitis extending from the site of tissue injury induced by ear tags. The affected mice further develop several signs of systemic lupus with hypergammaglobulinemia, autoantibodies to DNA, proteinuria, and kidney pathology. Ro52, which was recently identified as an E3 ligase, mediates ubiquitination of several members of the interferon regulatory factor (IRF) family, and the Ro52-deficient mice have an enhanced production of proinflammatory cytokines that are regulated by the IRF transcription factors, including cytokines involved in the Th17 pathway (interleukin [IL] 6, IL-12/IL-23p40, and IL-17). Loss of IL-23/IL-17 by genetic deletion of IL-23/p19 in the Ro52(-/-) mice conferred protection from skin disease and systemic autoimmunity. These data reveal that the lupus-associated Ro52 protein is an important negative regulator of proinflammatory cytokine production, and they provide a mechanism by which a defective Ro52 function can lead to tissue inflammation and systemic autoimmunity through the IL-23-Th17 pathway.

Histopathologic and clinical outcome of rituximab treatment in patients with cyclophosphamide-resistant proliferative lupus nephritis.

OBJECTIVE: Rituximab is a monoclonal antibody directed against the CD20 marker of B cells. Because of its ability to deplete B lymphocytes, it has been suggested that the drug could be of benefit in B cell-dependent diseases, including systemic lupus erythematosus (SLE). The purpose of this study was to investigate the histopathologic and clinical effects of combination treatment with rituximab and cyclophosphamide (CYC) in patients with CYC-resistant proliferative lupus nephritis. METHODS: Seven female patients with proliferative lupus nephritis were treated with rituximab in combination with CYC. Renal biopsies were performed before treatment and during followup. SLE activity was evaluated by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the British Isles Lupus Assessment Group index. In 6 of the 7 patients, immunostaining of lymphocyte subpopulations in the renal tissue was performed before treatment and during followup. RESULTS: At 6 months of followup, significant clinical improvement was noted, with a reduction in SLEDAI scores (from a mean of 15 to 3), anti-double-stranded DNA antibody levels (from a mean of 174 IU/ml to 56 IU/ml), and anti-C1q antibody levels (from a mean of 35 units/ml to 22 units/ml). On repeat renal biopsy, improvement in the histopathologic class of nephritis occurred in a majority of patients, and a decrease in the renal activity index was noted (from 6 to 3). A reduction in the number of CD3, CD4, and CD20 cells in the renal interstitium was noted in 50% of the patients on repeat biopsy. CONCLUSION: At 6 months of followup, all patients had responded both clinically and histopathologically to combination therapy. For patients with proliferative lupus nephritis who fail to respond to conventional immunosuppressive therapy including CYC, combined treatment with rituximab and CYC may constitute a new treatment option.

Tubular mitochondrial alterations in neonatal rats subjected to RAS inhibition.

Pharmacological interruption of the angiotensin II (ANG II) type 1 receptor signaling during nephrogenesis in rats perturbs renal tubular development. This study aimed to further investigate tubular developmental defects in neonatal rats subjected to ANG II inhibition with enalapril. We evaluated tubular ultrastructural changes using electron microscopy and estimated spectrophotometrically activity or concentrations of succinate dehydrogenase (SDH), cytochromes a and c, which are components of mitochondrial respiratory chain, on postnatal days 2 and 9 (PD2 and PD9). Renal expression of sodium-potassium adenosinetriphosphatase (Na(+)-K(+)-ATPase) and two reflectors of mitochondrial biogenesis [mitochondrial transcription factor A (TFAM) and translocase of outer mitochondrial membrane 20 (TOM20)] also were studied using Western immunoblotting and immunohistochemistry. Enalapril disrupted inner mitochondrial membranes of developing cortical and medullary tubular cells on PD2 and PD9. These findings were paralleled by impaired mitochondrial respiratory function, as revealed from the changes in components of the mitochondrial respiratory chain, such as decreased cytochrome c level in the cortex and medulla on PD2 and PD9, decreased cytochrome a level in the cortex and medulla on PD2, and diminished cortical SDH activity on PD2 and PD9. Moreover, tubular expression of the most active energy-consuming pump Na(+)-K(+)-ATPase was decreased by enalapril treatment. Renal expression of TFAM and TOM20 was not altered by neonatal enalapril treatment. Because nephrogenesis is a highly energy-demanding biological process, with the energy being utilized for renal growth and transport activities, the structural-functional alterations of the mitochondria induced by neonatal enalapril treatment may provide the propensity for the tubular developmental defect.

Molecular cytogenetic characterization shows higher genetic homogeneity in conventional renal cell carcinoma compared to other kidney cancers.

In this study seven primary kidney tumors out of 13 were cytogenetically characterized by comparative genomic hybridization (CGH) on the surgical specimens as well as by spectral karyotyping (SKY) analysis after short-term culturing. In two of the seven cases only a normal karyotype was identified. Non-clonal aberrations were observed in four of the seven cases. Overall numerical alterations were more frequent than structural changes. The two structural alterations identified constituted of a deletion of the short arm of chromosome 3 in a conventional renal cell carcinoma (RCC), and a ring chromosome derived from chromosome 8 in a papillary RCC. By CGH gains of copy number were revealed on chromosomes 3, 5, 7, 8q, and 20, while the losses encompassed 3p and 17p. In the papillary RCCs only gains were found. Comparison between SKY and CGH data suggests that the conventional RCCs are genetically more homogeneous than the other types of kidney cancer. In the two papillary RCCs, trisomies of chromosomes 7 and 17 were typical findings. In the transitional cell carcinoma different findings by CGH and SKY would suggest that these tumors constitute a heterogeneous population of tumor cells which could represent different steps of somatic evolution of tumors.

Receptors for Escherichia coli adhesins in the genitourinary tract in a non-human primate.

OBJECTIVE: To study the expression of receptors allowing adhesin-mediated binding of Escherichia coli to urogenital tissues ranging from the kidney to the vagina in cynomolgus monkeys using an in situ assay. MATERIAL AND METHODS: Receptors specific for four relevant adhesins were investigated: PapG and PrsG of P-fimbriae binding to gal-alpha(1-4)gal glycosphingolipids (preferentially globoside and the Forssman antigen, respectively): and two variants of FimH of type 1 fimbriae, one binding to monomannose/trimannose and the other to trimannose only. To ascertain the specificity of the observed bindings we used adhesion inhibition by receptor analogues as well as E. coli adhesin knockout mutants. RESULTS: The distributions of PapG and FimH receptors in monkey tissues showed great similarities to available data in humans. Whilst monomannose receptors were expressed on the surface epithelium in both the monkey bladder and ureter, trimannose receptors were not. The different distribution of FimH isoreceptors and the heterogeneity of FimH adhesin variants among E. coli may explain contradictory earlier findings in type 1 fimbriae-mediated adhesion to the human bladder and to renal tissues. We also found evidence of a hitherto unknown type of host-aggressor interaction on vaginal and urethral mucosa, which was not discovered until type 1 fimbriae had been eliminated. CONCLUSIONS: A precise molecular fit between host receptors and bacterial lectins is important in infectious pathogenesis. We conclude that urinary tract infection in the cynomolgus monkey is a relevant model of the human disease because of the similarity in the expression of receptors for E. coli adhesins on epithelial surfaces in the two species.

Loss of 14q31-q32.2 in renal cell carcinoma is associated with high malignancy grade and poor survival.

The present study was undertaken to further approach the importance of 14q deletions in renal cell carcinoma (RCC) development. The initial screening using 2 RFLP markers from distal 14q identified loss of heterozygosity (LOH) in 17 of 45 informative cases (38%). In addition, in 37 patients with primary RCCs, it was shown that cases with LOH at D14S1 had significantly shorter survival as compared to cases with-out LOH (p<0.005). Subsequently, 19 primary tumors and 6 metastases were genotyped for 20 polymorphic markers and the findings were evaluated in relation to the clinical characteristics of the primary tumor and the survival during follow-up. Overall LOH was identified in 11 of the primary tumors (58%) and 4 of the metastases (66%). In metastases as well as in primary tumors the highest frequency of LOH was detected with markers from the distal part of the chromosome i.e., 14q32. Five minimal regions of overlapping deletions were identified, three of which (II, IV and V) were defined from the primary RCCs. From centromere to telomere these include region I proximal of D14S259, region II between D14S255 and D14S588, region III in the D14S61-D14S617 interval, region IV between D14S617 and D14S260, and region V telomeric of D14S1007. For the primary tumors, losses in regions IV and V were each significantly associated with high tumor grade (i.e., grade 3; p<0.05). Furthermore, LOH within region IV was also associated with a significantly shorter survival (p=0.02). In conclusion, the high frequency of distal 14q LOH supports the relevance of this alteration for the development of RCC.

Interobserver reproducibility of modified Gleason score in radical prostatectomy specimens.

The Gleason score (GS) of prostate cancer is calculated by adding primary and secondary Gleason grades with patterns occupying less than 5% of the tumour often not included despite their probable prognostic significance. A modified Gleason score (mGS) comprising primary and tertiary patterns of higher grade has been proposed, but its interobserver variability has yet to be elucidated. Slides from 69 consecutive prostatectomy specimens were circulated among four genitourinary pathologists. GS and mGS were assessed, and results were compared in pairs. Mean weighted kappa for GS and mGS were 0.56 (range 0.52-0.66) and 0.58 (range 0.49-0.74), respectively. The difference between GS and mGS was 0, 1 and 2 score units in 66%, 26% and 8%, respectively, mean 0.41 score units (range 0.24-0.51). The increment was greater for transition-zone tumours than for peripheral-zone tumours (0.63 and 0.35 score units, respectively, P=0.002). An odd mGS (5, 7 or 9) was more often given than an odd GS (77% and 62%, respectively, P<0.001). Disagreement between observers greater than 1 score unit was more common with mGS than GS (18% and 4%, respectively, P<0.001). In conclusion, overall mean weighted kappa for interobserver reproducibility of mGS is at least as high as that of GS. However, there is a clustering of mGS in odd scores, and severe disagreement is more commonly observed than with GS. Training of mGS assessment would possibly improve agreement. Tertiary Gleason patterns need to be better defined.

Neonatal RAS inhibition changes the phenotype of the developing thick ascending limb of Henle.

Pharmacological interruption of angiotensin II type 1 (AT(1)) receptor signaling during nephrogenesis in rats perturbs renal tubular development. Perturbed tubulogenesis may contribute to long-term impairment of urinary concentrating ability, which is the main functional irreversible defect. The aim of this study was to further characterize tubular developmental deficits in neonatal rats, focusing on the thick ascending limb of Henle (TALH), known to undergo profound developmental changes and to be involved in urine-concentrating mechanisms. We have carried out immunohistochemistry and Western immunoblotting using antibodies directed against the major histocompatibility complex class II (MHC II) molecule and different TALH-specific markers, namely, cyclooxygenase-2 (COX-2), Tamm-Horsfall glycoprotein (THP), and the bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter (BSC-1/NKCC2). Immunohistochemistry demonstrated expression of MHC II, COX-2, THP, and BSC-1/NKCC2 proteins in normally developing TALH cells. The AT(1)-receptor antagonist losartan abolished MHC II expression exclusively in the developing TALH cells. Increased expression of COX-2 and THP was observed in the TALH cells of losartan-treated rats. Western immunoblotting confirmed increases in cortical and medullary COX-2 and THP abundance and revealed a decrease in cortical BSC-1/NKCC2 abundance in response to losartan treatment. We conclude that neonatal losartan treatment causes significant changes in the phenotype of the developing TALH in the rat.