Soluble interleukin-2 receptor in children with reflux nephropathy

Biomarkers in vesicoureteral reflux: an overview

Aim: This article aimed to review the role of cytokines, chemokines, growth factors and cellular adhesion molecules as biomarkers for vesicoureteral reflux (VUR) and reflux nephropathy (RN). Methods: We reviewed articles from 1979 onward by searching PubMed and Scopus utilizing the combination of words: 'VUR' or 'RN' and each one of the biomarkers. Results: Genetic, inflammatory, fibrogenic, environmental and epigenetic factors responsible for renal scarring need to be better understood. TGF-β, IL-10, IL-6, IL-8 and TNF seem to exert a role in VUR particularly in RN based on the current literature. Serum levels of procalcitonin have been also associated with high-grade VUR and RN. These molecules should be more intensively evaluated as potential biomarkers for renal scarring in VUR. Conclusion: Further studies are necessary to define which molecules will really be of utility in clinical decisions and as therapeutic targets for VUR and RN.

Clinical significance of urinary interleukin-6 in children with reflux nephropathy

PURPOSE

We determined urinary interleukin-6 (IL-6) in children with reflux nephropathy to evaluate the clinical significance of this cytokine in the progression of renal injury.

MATERIALS AND METHODS

Enrolled in this study were 34 boys and 32 girls in whom 99mtechnetium dimercapto-succinic acid renal scan showed renal scarring. Vesicoureteral reflux had been corrected surgically at least 3 years before study entry. Urinary IL-6 was determined by enzyme-linked immunosorbent assay using spot urine samples. Simultaneously we measured serum creatinine, beta2-microglobulin, alpha1-microglobulin, urinary alpha1-microglobulin and albumin. In addition, IL-6 expression was assessed by immunohistochemical study in the scarred kidneys of 3 boys and 1 girl who underwent nephrectomy due to severe reflux nephropathy with little function on renal scan.

RESULTS

Urinary IL-6 was significantly higher in children with severe bilateral renal scarring than in those with mild scarring and normal controls. Urinary IL-6 correlated significantly with serum alpha1-microglobulin (Spearman test p <0. 03), beta2-microglobulin (p <0.003), creatinine (p <0.02) and urinary albumin (p <0.0001). Histological evaluation revealed that IL-6 was predominantly expressed in the tubules in and adjacent to fibrotic areas.

CONCLUSIONS

Our observations indicate that tubular IL-6 may be involved in the pathogenesis of tubulointerstitial injury in reflux nephropathy and urinary IL-6 may be a useful tool for monitoring the progression of reflux nephropathy.

Vesicoureteral reflux and urinary tract infections

Urinary tract infection is a common problem in children. The combination of vesico-ureteric reflux (VUR) and urinary tract infection may predispose children to pyelonephritis and subsequent complications. This review outlines the modifications suggested in the recent literature in the protocol for investigations and diagnosing VUR. Recent interest has been expressed in studying certain molecular markers to measure non-invasively renal damage in children with VUR. Long term results of comparative trials between medical and surgical management have been published recently.

A review on urinary proteins in outflow disease of the upper urinary tract

INTRODUCTION

[corrected] No review articles on outflow disease of the upper urinary tract discuss urinary protein excretion.

DISCUSSION

Following acute partial and/or complete ureteral obstruction (UO) or chronic partial UO, alpha-1-microglobulin excretion is significantly higher than in the reference population or patients with proven renal dilatation without obstruction, but is not found to be diagnostic for these conditions as such. Chronic partial UO is followed first by a destructive and then by a steady-state phase in renal damage. The observed increase in tubular proteinuria during the destructive phase correlates with the decrease in absolute dimercaptosuccinic acid (DMSA) uptake. If the destructive phase is not followed by a stable phase, a mixed tubular and glomerular proteinuria is seen. Urinary alpha-1-microglobulin excretion is found to be diagnostically useful in vesico-ureteral reflux (VUR) patients, increases with higher intravesical-intrapyelic pressure, correlates with the decrease in absolute DMSA uptake or with urinary epidermal growth factor excretion (both markers of the number of functioning nephrons) and predicts the outcome after treatment.

CONCLUSION

alpha-1-Microglobulin is useful in the detection of renal tubular damage in patients with outflow disease of the upper tract, is diagnostic for VUR but is not so for ureteral obstruction.

Recent advances in the understanding and management of primary vesicoureteral reflux and reflux nephropathy

Vesicoureteral reflux and reflux nephropathy continue to be active areas of clinical investigation. There is conclusive evidence that vesicoureteral reflux is inherited. Prenatal diagnosis offers the opportunity for early recognition and intervention that may reduce the incidence of complications of vesicoureteral reflux such as pyelonephritis episodes and the development of reflux nephropathy.

Expression of platelet-derived endothelial cell growth factor and its potential role in up-regulation of angiogenesis in scarred kidneys secondary to urinary tract diseases

The mechanism of neovascularization secondary to renal interstitial fibrosis is not well understood. Platelet-derived endothelial cell growth factor (PD-ECGF) is known to promote angiogenesis. We examined the expression of PD-ECGF immunohistochemically in 9 normal kidneys and 26 scarred kidneys secondary to urinary tract diseases. To estimate up-regulation of angiogenesis, microvessels were counted by immunostaining endothelial cells for CD34. Immunostaining of PD-ECGF was observed in most Bowman's capsules, occasional tubules, and some interstitial mononuclear cells in normal kidneys. A remarkable increase of immunostained PD-ECGF was found in the tubules and interstitial mononuclear infiltrates in the scarred kidneys. The predominant cell type in the infiltrate was T cells (CD3(+)). The microvessel count and mean numbers of PD-ECGF(+) tubular and interstitial mononuclear cells increased with increasing interstitial fibrosis. A significant correlation was noted between microvessel count and the number of PD-ECGF(+) tubular cells (P = 0.0002) or PD-ECGF(+) interstitial mononuclear cells (P < 0.0001). Immunostaining of endogrin, a marker of endothelial proliferation, increased in the microvessels located in the fibrotic interstitial spaces. These results suggest that angiogenesis may play a critical role in the progression of tubulointerstitial injuries and that up-regulation of PD-ECGF may contribute to neovascularization.