Growth Differentiation Factor 15 in Children with Chronic Kidney Disease and after Renal Transplantation.

Growth differentiation factor 15 (GDF-15) is strongly associated with cardiovascular disease (CVD). The aim of our study was to evaluate plasma and urinary levels of GDF-15 after pediatric renal transplantation (Rtx) and in children with chronic kidney disease (CKD) and its associations to cardiovascular risk factors. In this cross-sectional study, GDF-15 was measured in plasma and urine from 53 children with a renal transplant and 83 children with CKD and related to cardiovascular risk factors (hypertension, obesity, and cholesterol) and kidney function. Forty healthy children served as a control group. Plasma levels of GDF-15 (median and range) for a Tx (transplantation) cohort, CKD cohort, and healthy controls were, respectively, 865 ng/L (463-3039 ng/L), 508 ng/L (183-3279 ng/L), and 390 ng/L (306-657 ng/L). The CKD and Tx cohorts both had significantly higher GDF-15 levels than the control group (p < 0.001). Univariate associations between GDF-15 and hyperuricemia (p < 0.001), elevated triglycerides (p = 0.028), low HDL (p = 0.038), and obesity (p = 0.028) were found. However, mGFR (p < 0.001) and hemoglobin (p < 0.001) were the only significant predictors of GDF-15 in an adjusted analysis. Urinary GDF-15/creatinine ratios were 448 ng/mmol (74-5013 ng/mmol) and 540 ng/mmol (5-14960 ng/mmol) in the Tx cohort and CKD cohort, respectively. In the CKD cohort, it was weakly correlated to mGFR (r = -0.343, p = 0.002). Plasma levels of GDF-15 are elevated in children with CKD and after Rtx. The levels were not associated with traditional cardiovascular risk factors but strongly associated with renal function.

Identification of urinary candidate biomarkers of cisplatin-induced nephrotoxicity in patients with carcinoma.

Nephrotoxicity limits the use of cisplatin (CP) in cancer therapy; however, current clinical measures of renal health do not reflect low degrees of kidney injury. Therefore, discovering new biomarkers for CP-induced acute kidney injury (AKI) is essential for monitoring kidney health during therapy. To identify novel candidate biomarkers in urine for reduced renal function due to CP therapy, we conducted a pilot study on cancer patients eligible for CP treatment. Urine from 30 patients was collected before (baseline) and after 3d of intravenous CP infusion. Urine samples were subjected to Isobaric Tag for Relative Absolute Quantitation (iTRAQ) analysis. Biological roles and pathways for the proteins with altered urine concentrations were identified using bioinformatic tools ITRAQ analysis detected 1411 proteins, 12 of which showed significantly altered levels. Growth differentiation factor-15 (GDF15), leucine-rich alpha-2-glycoprotein 1 (LRG1), and secreted phosphoprotein 1 (SPP1/ osteopontin, OPN) were identified as potential candidate markers by proteomic analysis and were validated by ELISA in another 30 patients and in a CP-induced AKI mouse model. Therefore, GDF15, LRG1, and SPP1 may be applied as novel candidate urinary markers of kidney injury after cisplatin treatment. These findings may facilitate the development of new methods to monitor kidney function, particularly in CP-based chemotherapy. SIGNIFICANCE: Cisplatin is pivotal for cancer treatment; however, nephrotoxicity limits its use. Clinical measures for renal health are not reflective of early signs of acute kidney injury. Thus, new indicators of the state of renal health following cisplatin treatment will have to be discovered. This study reports the use of proteomics to mine for candidate markers of kidney injury in the urine of patients undergoing treatment with cisplatin. Results were experimentally validated using patient urine and a mouse model of cisplatin-induced acute kidney injury. The novel candidate biomarkers reported in this study may be used for the non-invasive monitoring of renal health and in mitigating the side-effects of cisplatin during the course of cancer treatment.

Identification of six cardiovascular risk biomarkers in the young population: A promising tool for early prevention.

BACKGROUND AND AIMS: The predictive value of traditional CV risk calculators is limited. Novel indicators of CVD progression are needed particularly in the young population. The main aim of this study was the identification of a molecular profile with added value to classical CV risk estimation. METHODS: Eighty-one subjects (30-50 years) were classified in 3 groups according to their CV risk: healthy subjects; individuals with CV risk factors; and those who had suffered a previous CV event. The urine proteome was quantitatively analyzed and significantly altered proteins were identified between patients' groups, either related to CV risk or established organ damage. Target-MS and ELISA were used for confirmation in independent patients' cohorts. Systems Biology Analysis (SBA) was carried out to identify functional categories behind CVD. RESULTS: 4309 proteins were identified, 75 of them differentially expressed. ADX, ECP, FETUB, GDF15, GUAD and NOTCH1 compose a fingerprint positively correlating with lifetime risk estimate (LTR QRISK). Best performance ROC curve was obtained when ECP, GDF15 and GUAD were combined (AUC = 0.96). SBA revealed oxidative stress response, dilated cardiomyopathy, signaling by Wnt and proteasome, as main functional processes related to CV risk. CONCLUSIONS: A novel urinary protein signature is shown, which correlates with CV risk estimation in young individuals. Pending further confirmation, this six-protein-panel could help in CV risk assessment.

The renal transcriptome of db/db mice identifies putative urinary biomarker proteins in patients with type 2 diabetes: a pilot study.

We sought to identify novel urinary biomarkers of kidney function in type 2 diabetes. We screened the renal transcriptome of db/db and db/m mice for differentially expressed mRNA transcripts that encode secreted proteins with human orthologs. Whether elevated urine levels of the orthologous proteins correlated with diminished glomerular filtration rate was tested in a cross-sectional study of n = 56 patients with type 2 diabetes. We identified 36 putative biomarker genes in db/db kidneys: 31 upregulated and 5 downregulated. Urinary protein levels of six selected candidates (endothelin-1, lipocalin-2, transforming growth factor-ß, growth and differentiation factor-15, interleukin-6, and macrophage chemoattractant protein-1) were elevated in type 2 diabetic patients with subnormal glomerular filtration rate (i.e., <90 ml·min(-1)·1.73 m(-2)), independent of microalbuminuria, age, sex, race, and use of angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists. In contrast, urinary levels of fibroblast growth factor were not increased. A composite variable of urine albumin and any of the six candidate markers was associated with subnormal estimated glomerular filtration rate more closely than albumin alone. In addition, urinary endothelin-1, growth and differentiation factor-15, and interleukin-6 were associated with a marker of proximal tubule damage, N-acetyl-ß-d-glucosaminidase activity. These results suggest that gene expression profiling in diabetic mouse kidney can complement existing proteomic-based approaches for renal biomarker discovery in humans.