Magnetic resonance imaging 3T and total fibrotic volume in autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal hereditary disorder. Several authors have attempted to identify a kidney damage marker for predicting the prognosis and the effectiveness of therapy in ADPKD. AIM: To identify and quantify ADPKD, through a novel magnetic resonance imaging protocol with 3 Tesla (MRI 3Tesla), the presence of parenchymal fibrotic tissue at early stage of disease, able to correlate the glomerular filtrate and to predict the loss of the renal function. METHODS: A total of 15 ADPKD patients had undergone renal testing on MRI 3Tesla at T0 and were revaluated after follow up (T1) of 5 years. We have evaluated renal function, plasma aldosterone concentration (PAC), insulin resistance and surrogate markers of atherosclerosis (carotid intima-media thickness, ankle/brachial index (ABI) and left ventricular mass index (LVMI). RESULTS: Our study showed a significant negative correlation between total kidney volume (TKV) and estimated glomerular filtration rate (eGFR) during observation (P < 0.02). We showed a negative correlation between eGFR with total fibrotic volume (TFV) (P < 0.04) and total perfusion volume/TKV (P < 0.02). Moreover TFV was correlated positively with PAC (P < 0.05), insulin values (P < 0.05), ABI (P < 0.05) and LVMI (P < 0.01). CONCLUSION: The MRI 3Tesla, despite the high costs, could be considered as a useful and non-invasive method in the evaluation of fibrotic tissue and progression of the disease in ADPKD patients. Further clinical trials on larger groups are due to confirm the results of this pilot study, suggesting that MRI 3Tesla can be useful to evaluate the effectiveness of new therapeutic strategies.

Early Markers of Cardiovascular Risk in Autosomal Dominant Polycystic Kidney Disease.

BACKGROUND/AIMS: Cardiovascular disease is the most frequent cause of morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD) patients, often before the onset of renal failure, and the pathogenetic mechanism is not yet well elucidated. The aim of the study was to identify early and noninvasive markers of cardiovascular risk in young ADPKD patients, in the early stages of disease. METHODS: A total of 26 patients with ADPKD and 24 control group, matched for age and sex, were enrolled, and we have assessed inflammatory indexes, mineral metabolism, metabolic state and markers of atherosclerosis and endothelial dysfunction (carotid intima media thickness (IMT), ankle brachial index (ABI), flow mediated dilation (FMD), renal resistive index (RRI), left ventricular mass index (LVMI)) and cardiopulmonary exercise testing (CPET), maximal O2 uptake (V'O2max), and O2 uptake at lactic acid threshold (V'O2@LT). RESULTS: The ADPKD patients compared to control group, showed a significant higher mean value of LVMI, RRI, homocysteine (Hcy), Homeostasis Model Assessment-insulin resistance (HOMA-IR), serum uric acid (SUA), Cardiac-troponinT (cTnT) and intact parathyroid hormone (iPTH) (p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, p=0.007, p=0.019; respectively), and a lower value of FMD and 25-hydroxyvitaminD (25-OH-VitD) (p<0.001, p<0.001) with reduced parameters of exercise tolerance, as V'O2max, V'O2max/Kg and V'O2max (% predicted) (p<0.001, p<0.001, p=0.018; respectively), and metabolic response indexes (V'O2@LT, V'O2 @LT%, V'O2@LT/Kg,) (p<0.001, p=0.14, p<0.001; respectively). Moreover, inflammatory indexes were significantly higher in ADPKD patients, and we found a positive correlation between HOMA-IR and C-reactive protein (CRP) (r=0.507, p=0.008), and a negative correlation between HOMA-IR and 25-OH-VitD (r=-0.585, p=0.002). CONCLUSION: In our study, ADPKD patients, in the early stages of disease, showed a greater insulin resistance, endothelial dysfunction, inflammation and mineral metabolism disorders, respect to control group. Moreover, these patients presented reduced tolerance to stress, and decreased anaerobic threshold to CPET. Our results indicate a major and early cardiovascular risk in ADPKD patients. Therefore early and noninvasive markers of cardiovascular risk and CPET should be carried out, in ADPKD patients, in the early stages of disease, despite the cost implication.