Background Age- and height-adjusted total kidney volume is currently considered the best prognosticator in patients with autosomal dominant polycystic kidney disease. We tested the ratio of urinary... Show moreBackground Age- and height-adjusted total kidney volume is currently considered the best prognosticator in patients with autosomal dominant polycystic kidney disease. We tested the ratio of urinary epidermal growth factor and monocyte chemotactic peptide 1 for the prediction of the Mayo Clinic Imaging Classes. Methods Urinary epidermal growth factor and monocyte chemotactic peptide 1 levels were measured in two independent cohorts (discovery, n = 74 and validation set, n = 177) and healthy controls (n = 59) by immunological assay. Magnetic resonance imaging parameters were used for total kidney volume calculation and the Mayo Clinic Imaging Classification defined slow (1A-1B) and fast progressors (1C-1E). Microarray and quantitative gene expression analysis were used to test epidermal growth factor and monocyte chemotactic peptide 1 gene expression. Results Baseline ratio of urinary epidermal growth factor and monocyte chemotactic peptide 1 correlated with total kidney volume adjusted for height (r = - 0.6, p < 0.001), estimated glomerular filtration rate (r = 0.69 p < 0.001), discriminated between Mayo Clinic Imaging Classes (p < 0.001), and predicted the variation of estimated glomerular filtration rate at 10 years (r = - 0.51, p < 0.001). Conditional Inference Trees identified cut-off levels of the ratio of urinary epidermal growth factor and monocyte chemotactic peptide 1 for slow and fast progressors at > 132 (100% slow) and < 25.76 (89% and 86% fast, according to age), with 94% sensitivity and 66% specificity (p = 6.51E-16). Further, the ratio of urinary epidermal growth factor and monocyte chemotactic peptide 1 at baseline showed a positive correlation (p = 0.006, r = 0.36) with renal outcome (delta-estimated glomerular filtration rate per year, over a mean follow-up of 4.2 +/- 1.2 years). Changes in the urinary epidermal growth factor and monocyte chemotactic peptide 1 were mirrored by gene expression levels in both human kidney cysts (epidermal growth factor: - 5.6-fold, fdr = 0.001; monocyte chemotactic peptide 1: 3.1-fold, fdr = 0.03) and Pkd1 knock-out mouse kidney (Egf: - 14.8-fold, fdr = 2.37E-20, Mcp1: 2.8-fold, fdr = 6.82E-15). Conclusion The ratio of urinary epidermal growth factor and monocyte chemotactic peptide 1 is a non-invasive pathophysiological biomarker that can be used for clinical risk stratification in autosomal dominant polycystic kidney disease. Show less
Autosomal Dominant Polycystic Kidney Disease, ADPKD, is a common inherited disorder that affects the kidneys. Progressive development of renal cysts ultimately results in chronic renal failure. To... Show moreAutosomal Dominant Polycystic Kidney Disease, ADPKD, is a common inherited disorder that affects the kidneys. Progressive development of renal cysts ultimately results in chronic renal failure. To develop therapies for ADPKD patients, further insight into the mechanism of cyst formation is required. We set out to investigate the molecular and cellular processes that are disrupted in ADPKD. In the introduction, normal function of the kidney and renal epithelium is discussed. This is followed by an overview of the literature available on the structural and functional properties of polycystin-1 and polycystin-2, the proteins responsible for ADPKD. Finally, our data on polycystin-1 and polycystin-2 function and ADPKD cyst formation is outlined and discussed in the remainder of the thesis. Show less
