Perlecan as a biomarker for renal dysfunction

1. A method for treating dyspnea in a subject presenting with rapid onset of the dyspnea, wherein the subject has not had a kidney transplant, and wherein the method comprises:

a) identifying the subject presenting with rapid onset of said dyspnea as having dyspnea associated with or caused by renal dysfunction and as being in need of treatment of renal dysfunction by having an assay conducted, wherein the assay comprises:

(i) contacting an antibody or an aptamer capable of specifically detecting the Endorepellin domain of PERLECAN with a blood sample from the subject;

(ii) measuring a quantity of the Endorepellin domain of PERLECAN in the blood sample by determining the binding of the antibody or aptamer to the Endorepellin domain of PERLECAN;

(iii) converting the measured quantity of the Endorepellin domain of PERLECAN in the blood sample to a glomerular filtration rate (GFR) value; and

(iv) comparing the GFR value determined in (iii) with a reference value GFR value, said reference value representing one or more of a known diagnosis, prediction, or prognosis of renal dysfunction or normal renal function, and finding a reduced GFR value determined in (iii) from said reference value so as to identify the subject as being in need of the treatment for renal dysfunction; and

b) treating the subject having the deviation for renal dysfunction, thereby treating dyspnea, with a treatment or therapy selected from the group consisting of low-potassium diet, low phosphorous diet, low potassium and low phosphorus diet, phosphorous-lowering medications, red-blood-cell-production-stimulating agents, iron supplements, blood pressure medications, vitamin supplements, haemodialysis, ultrafiltration, peritoneal dialysis and kidney transplantation.

2. The method according to claim 1 , wherein dyspnea is associated or caused by renal dysfunction, wherein the renal dysfunction is acute renal failure, chronic renal failure, is associated or caused by renal fibrosis, or is associated with or caused by type II diabetes.

3. The method according to claim 1 , wherein the subject is a postoperative patient, a critically ill patient, or a postoperative and critically ill patient.

4. The method according to claim 1 , wherein a threshold between normal and reduced GFR is set at a value between about 50 and about 70 ml/min/1.73 m 2 , wherein a value above said threshold denotes normal GFR and a value below said threshold denotes reduced GFR.

5. The method according to claim 4 , wherein the threshold is set at a value at 60 ml/min/1.73 m 2 .

6. The method according to claim 1 , wherein the identification step a) further comprises:

(i) measuring the quantity of the Endorepellin domain of PERLECAN and one or more of the presence or absence; or quantity of one or more other biomarkers in the blood sample from the subject;

(ii) using the measurements of (i) to establish a subject profile of the quantity of the Endorepellin domain of PERLECAN and one or more of the presence or absence, or quantity of said one or more other biomarkers in the subject;

(iii) comparing said subject profile of (ii) to a reference profile of the quantity of the Endorepellin domain of PERLECAN and one or more of the presence or absence, or quantity of said one or more other biomarkers, said reference profile representing one or more of a known diagnosis, prediction, or prognosis of renal dysfunction or normal renal function;

(iv) finding a deviation or no deviation of the subject profile of (ii) from the reference profile; and

(v) attributing said finding of deviation or no deviation to one or more of a particular diagnosis, prediction, or prognosis of renal dysfunction in the subject presenting with rapid onset of the dyspnea wherein the subject has not had a kidney transplant.

7. The method according to claim 6 , wherein said other biomarker is selected from the group consisting of creatinine, Cystatin C, neutrophil gelatinase associated lipocalin (NGAL), beta-trace protein, kidney injury molecule 1 (KIM-1), interleukin-18 (IL-18), B-type natriuretic peptide (BNP), pro-B-type natriuretic peptide (proBNP), amino terminal pro-B-type natriuretic peptide (NTproBNP), latent transforming growth factor beta binding protein 2 (LTBP2) and C-reactive peptide.

8. The method according to claim 6 , wherein the one or more of quantity, or presence or absence of the one or more other biomarkers is measured using a binding agent capable of specifically binding to said one or more other biomarkers.

9. The method according to claim 6 , wherein the one or more of quantity of, or presence or absence of the one or more other biomarkers is measured using an immunoassay technology, a mass spectrometry analysis method, a chromatography method, or a combination of said methods, or using RNA analysis tools, wherein the RNA analysis tools are northern blotting, RT-PCR or quantitative RT-PCR.