High urinary excretion of kidney injury molecule-1 is an independent predictor of end-stage renal disease in patients with IgA nephropathy.
ABSTRACT The variable course of immunoglobulin A nephropathy (IgAN) warrants accurate tools for the prediction of progression. Urinary kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are markers for the detection of early tubular damage caused by various renal conditions. We evaluated the prognostic value of these markers in patients with IgAN.
We included patients (n = 65, 72% male, age 43 ± 13 years) with biopsy-proven IgAN, who were evaluated for proteinuria. Urinary KIM-1 and NGAL were measured by enzyme-linked immunosorbent assay. We analysed data using Cox regression for the outcome end-stage renal disease (ESRD).
Median serum creatinine was 142 μmol/L and proteinuria 2.2 g/day. During follow-up (median 75 months), 23 patients (35%) developed ESRD. In patients with IgAN median urinary KIM-1 excretion was 1.7 ng/min and NGAL excretion was 47 ng/min, both significantly higher than in healthy controls. KIM-1 and NGAL were correlated with proteinuria (r = 0.40 and 0.34, respectively, P < 0.01) and each other (r = 0.53, P < 0.01) but not with estimated glomerular filtration rate (eGFR). Interestingly, KIM-1 was not significantly correlated with the excretion of α(1)-microglobulin (α(1)m) and β(2)-microglobulin (β(2)m), known markers of tubular injury. Univariate analysis showed that baseline serum creatinine and urinary excretion of total protein, α(1)m, β(2)m, immunoglobulin G, KIM-1 and NGAL were significantly associated with ESRD. By multivariate analysis, serum creatinine and KIM-1 excretion proved to be significant independent predictors of ESRD.
KIM-1 and NGAL excretion are increased in patients with IgAN and correlate with proteinuria but not with eGFR. Baseline serum creatinine and urinary KIM-1, but not proteinuria, are independent predictors of ESRD.
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ABSTRACT: Abstract Background: Treatment with angiotensin receptor blockers (ARBs) is successful in mitigating IgA nephropathy (IgAN), independent of blood pressure changes, but the therapeutic role of ARB in advanced IgAN with impaired renal function is to be ascertained. The present study was performed to investigate the effect of losartan on advanced IgAN induced by staphylococcal enterotoxin B (SEB) combined with 5/6 nephrectomy in rats. Methods: Fifty-four male SD rats were randomly divided into three group: Rats in the model group were treated with SEB plus 5/6 nephrectomy, and those in the losartan group were gavaged with losartan (33.3 mg kg(-1 )d(-1)) besides the treatment with SEB plus 5/6 nephrectomy. The urine and blood biochemical changes of rats were tested. IgA, IgG, IgM and C3 depositions were studied dynamically with immunofluorescence. The renal tissue structures were observed under light microscopy. The expressions of TGF-β1, FN, alpha-SMA and FGF-1 in rat renal tissues were determined with immunohistochemical methods and real-time PCR. Results: At 12 weeks, rats with SEB treatment plus 5/6 nephrectomy showed gradually increased urinary red blood cell (URBC) with a gradual elevation of the 24 h urinary protein, serum BUN and Scr, but losartan treatment lowered the levels of 24 h urinary protein, serum BUN and Scr. A large number of IgA depositions in the mesangial area, glomerulosclerosis and tubulointerstitial fibrosis were found in the model group, and the losartan group showed relieved injury. The expressions of TGF-β1, FN, alpha-SMA and FGF-1 were significantly elevated in the model. Losartan lessened their expressions. Conclusion: Losartan treatment can delay the progression of advanced IgA nephropathy with impaired renal function.Renal Failure 07/2013; 35(6):812-8. · 0.94 Impact Factor
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ABSTRACT: Introduction: IgA nephropathy, the most prevalent glomerular disease in the world, requires a renal biopsy for diagnosis. Reliable biomarkers are needed for the non-invasive diagnosis of this disease and to more fully delineate its natural history and risk for progression. Areas covered: In this review, the authors examine serum levels of galactose-deficient IgA1 (Gd-IgA1) and glycan-specific IgG and IgA autoantibodies that are integral to pathogenesis of IgA nephropathy. They also explore biomarkers related to alternative and lectin pathways of complement activation and serum and urinary peptide biomarkers detected by mass spectrometric methods. The literature search included review of all publications having IgA nephropathy in the title that were cited in PubMed and Scopus over the past 10 years and a non-systematic review of abstracts published for the annual meetings of the American Society of Nephrology and the International Symposia on IgA Nephropathy. Expert opinion: Serum Gd-IgA1 level and glycan-specific autoantibody levels are prime candidates to become diagnostic biomarkers for IgA nephropathy because of their central role in the earliest stages of disease pathogenesis. Assays for serum levels of complement proteins C3 and factor H are readily available in clinical practice and deserve continued study, either alone or in tandem with total serum IgA or serum Gd-IgA1 levels, as prognostic biomarkers for patients with IgA nephropathy. Urinary peptidomic data are also reviewed because this approach can successfully differentiate patients with IgA nephropathy from healthy controls and from patients with other forms of renal disease.Expert Opinion on Medical Diagnostics 11/2013; 7(6):615-27.
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ABSTRACT: Kidney injury molecule-1 (KIM-1) is a biomarker useful for detecting early tubular damage and has been recently reported as a useful marker for evaluating kidney injury in IgA nephropathy (IgAN). We therefore investigated whether treatment decreases urinary KIM-1 excretion in IgAN. We prospectively enrolled 37 patients with biopsy-proven IgAN. Urinary KIM-1 was assessed before and after treatment, which included low salt diet, blood pressure control, pharmacotherapy with angiotensin receptor blockers and/or angiotensin converting enzyme inhibitors, and immunosuppressive agents as necessary. The median treatment duration was 24 months. Urinary KIM-1/creatinine (Cr) was significantly decreased in patients with IgAN after treatment compared to baseline (P < 0.0001, 1.16 [0.51-1.83] vs 0.26 [0.12-0.65] ng/mg). There was a decrease in the amount of proteinuria after treatment, but it was not statistically significant (P = 0.052, 748.1 [405-1569.7] vs 569.2 [252.2-1114] g/d). Estimated glomerular filtration rate (eGFR) did not change with treatment (P = 0.599, 79.28 +/- 30.56 vs 80.98 +/- 32.37 ml/min/1.73 m2). Urinary KIM-1 was not correlated with proteinuria baseline or follow up (pre-: R = - 0.100, P = 0.577, post-: R = 0.001, P = 0.993). In patients with higher baseline urinary KIM-1, both urinary KIM-1 level and proteinuria were significantly decreased following treatment. Treatment decreases urinary KIM-1/Cr in patients with IgAN. It also reduces proteinuria in patients with higher baseline urinary KIM-1. These results suggest a potential role for urinary KIM-1 as a biomarker for predicting treatment response in IgAN, however, further study is needed to verify this.BMC Nephrology 07/2013; 14(1):139. · 1.64 Impact Factor