Factors affecting the progression of renal disease in autosomal-dominant polycystic kidney disease

Pregnancy outcomes in autosomal dominant polycystic kidney disease: a case-control study

OBJECTIVES

To determine whether autosomal dominant polycystic kidney disease (ADPKD) is associated with adverse fetal outcomes and maternal complications.

METHODS

We identified a cohort of 146 patients seen for pregnancy and cystic kidney disease at Mayo Clinic from 1975 to 2010. From this cohort, 54 patients met the ultrasound diagnostic criteria for ADPKD (ADPKD group), while the other 92 patients were diagnosed as "Simple Cyst" (control group). We compared the fetal and maternal outcomes of pregnancy and long-term maternal prognoses between these two groups.

RESULTS

Overall, the fetal complication rates were similar between the ADPKD and control groups. Rates of spontaneous abortion (15.1% versus 14%, p = 0.77) and premature birth (11.1% versus 6.8%, p = 0.44) were comparable between groups, while the rate of fetal distress (3.4% versus 0.7%, p < 0.01) was increased in the ADPKD group. The rate of preeclampsia in the patients with simple cysts (2%) was similar to that of the general population. In contrast, the pregnant ADPKD patients had higher risks for hypertension, proteinuria, edema, urinary tract infection, renal dysfunction and preeclampsia during their pregnancies.

CONCLUSION

ADPKD is associated with increased maternal complications during pregnancy, but only has a slight potential of increased rates of fetal complications.

Prevalence of severe hypokalaemia in patients with traumatic brain injury

INTRODUCTION

Patients with traumatic brain injury (TBI) are more vulnerable to develop hypokalaemia, we sought to investigate the prevalence, and the relationship between severe hypokalaemia and the mortality of traumatic brain injury patients.

METHODS

Isolated traumatic brain patients who had hypokalaemia (serum potassium <3.5mmol/L) and age≥14yrs were recruited into the study between January 2008 and March 2013. Hypokalaemia was defined as potassium level in the blood <3.5mmol/L during the hospitalisation, which was classified by severity: mild (3.0mmol/L≤K<3.5mmol/L), moderate (2.5mmol/L≤K<3.0mmol/L) and severe (K<2.5mmol/L). Multivariable logistic regression was performed to find the impact of hypokalaemia on mortality.

RESULTS

A total 375 cases were included in analysis. The peak incidence of severe hypokalaemia occurred in the first 24-96h. TBI patients with severe hypokalaemia had significantly higher serum sodium and lower serum phosphorus than those patients with mild or moderate hypokalaemia (p<0.001). Compare to other groups, the severe hypokalaemia group had the worst outcome. Moreover, the patients (n=15) who had severe hypokalaemia, hypernatraemia (Na>160mmol/L), and hypophosphataemia (P<0.3mmol/L) all died in hospital. Multiple logistic regression analysis resulted in decrease of GCS (OR=1.27; 95% CI=1.15-1.41; p<0.001) and potassium (OR=4.35; 95% CI=2.04-9.26; p<0.001) being associated with significant increased risk of mortality.

CONCLUSIONS

The peak incidence of severe hypokalaemia occurred in the first 24-96h. TBI patients with severe hypokalaemia are more vulnerable to develop hypophosphataemia and hypernatraemia than patients with mild and moderate hypokalaemia. Severe hypokalaemia are the independent risk factors for mortality in TBI patients.

Blood pressure in early autosomal dominant polycystic kidney disease

BACKGROUND

Hypertension is common in autosomal dominant polycystic kidney disease (ADPKD) and is associated with increased total kidney volume, activation of the renin-angiotensin-aldosterone system, and progression of kidney disease.

METHODS

In this double-blind, placebo-controlled trial, we randomly assigned 558 hypertensive participants with ADPKD (15 to 49 years of age, with an estimated glomerular filtration rate [GFR] >60 ml per minute per 1.73 m(2) of body-surface area) to either a standard blood-pressure target (120/70 to 130/80 mm Hg) or a low blood-pressure target (95/60 to 110/75 mm Hg) and to either an angiotensin-converting-enzyme inhibitor (lisinopril) plus an angiotensin-receptor blocker (telmisartan) or lisinopril plus placebo. The primary outcome was the annual percentage change in the total kidney volume.

RESULTS

The annual percentage increase in total kidney volume was significantly lower in the low-blood-pressure group than in the standard-blood-pressure group (5.6% vs. 6.6%, P=0.006), without significant differences between the lisinopril-telmisartan group and the lisinopril-placebo group. The rate of change in estimated GFR was similar in the two medication groups, with a negative slope difference in the short term in the low-blood-pressure group as compared with the standard-blood-pressure group (P<0.001) and a marginally positive slope difference in the long term (P=0.05). The left-ventricular-mass index decreased more in the low-blood-pressure group than in the standard-blood-pressure group (-1.17 vs. -0.57 g per square meter per year, P<0.001); urinary albumin excretion was reduced by 3.77% with the low-pressure target and increased by 2.43% with the standard target (P<0.001). Dizziness and light-headedness were more common in the low-blood-pressure group than in the standard-blood-pressure group (80.7% vs. 69.4%, P=0.002).

CONCLUSIONS

In early ADPKD, the combination of lisinopril and telmisartan did not significantly alter the rate of increase in total kidney volume. As compared with standard blood-pressure control, rigorous blood-pressure control was associated with a slower increase in total kidney volume, no overall change in the estimated GFR, a greater decline in the left-ventricular-mass index, and greater reduction in urinary albumin excretion. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; HALT-PKD [Study A] ClinicalTrials.gov number, NCT00283686.).

Treatments to slow progression of autosomal dominant polycystic kidney disease: systematic review and meta-analysis of randomized trials

AIM

Autosomal dominant polycystic kidney disease (ADPKD) is a monogenetic disorder that leads to kidney failure. Our aim was to undertake a meta-analysis of randomized trials of interventions that have been hypothesized to reduce the progression of total kidney volume (TKV) and renal function in ADPKD.

METHODS

Relevant trials were identified, and outcomes were: change in TKV, total cyst volume (TCV), renal function and adverse events. Meta-analysis used random effects, with results expressed as mean difference and risk ratio both with 95% confidence intervals (CI).

RESULTS

Eleven trials (2262 patients) were included. Compared with placebo, Target of Rapamycin complex 1 (TORC1) inhibitors (5 trials, n = 619), showed no significant change in TKV (P = 0.21), TCV (P = 0.06) or eGFR (P = 0.22). Somatostatin analogues (3 trials, n = 157) reduced TKV by 9% (95% CI -10.33 to -7.58%) but did not alter eGFR. The vasopressin receptor antagonist (n = 1455) attenuated TKV increase to 3%/year (95% CI -3.48 to -2.52) and slowed kidney function decline over a 3-year period. A single trial (n = 41) of eicosapentaenoic acid did not alter the progression of either TKV (P = 0.9) or renal dysfunction (P = 0.78). Adverse events were significant for interventions in all trials compared with placebo.

CONCLUSION

These data suggest that somatostatin analogues and vasopressin receptor antagonists attenuate TKV increase. The neutral effects of TORC1 inhibitors on TKV could be true, or due to heterogeneity in study population, drug efficacy and follow-up duration. In the future, further well-designed and powered trials of longer duration using new biomarkers or therapeutic agents with better tolerance are required.

Identification of people with autosomal dominant polycystic kidney disease using routine data: a cross sectional study

Background

Autosomal dominant polycystic kidney disease (ADPKD) causes progressive renal damage and is a leading cause of end-stage renal failure. With emerging therapies it is important to devise a method for early detection. We aimed to identify factors from routine clinical data which can be used to distinguish people with a high likelihood of having ADPKD in a primary health care setting.

Method

A cross-sectional study was undertaken using data from the Quality Intervention in Chronic Kidney Disease trial extracted from 127 primary care practices in England. The health records of 255 people with ADPKD were compared to the general population. Logistic regression was used to identify clinical features which distinguish ADPKD. These clinical features were used to stratify individual risk using a risk score tool.

Results

Renal impairment, proteinuria, haematuria, a diastolic blood pressure over 90 mmHg and multiple antihypertensive medications were more common in ADPKD than the general population and were used to build a regression model (area under the receiver operating characteristic curve; 0.79). Age, gender, haemoglobin and urinary tract infections were not associated with ADPKD. A risk score (range −3 to +10) of ≥0 gave a sensitivity of 70.2% and specificity 74.9% of for detection.

Conclusions

Stratification of ADPKD likelihood from routine data may be possible. This approach could be a valuable component of future screening programs although further longitudinal analyses are needed.

Safety study of somatostatin analogue octreotide for autosomal dominant polycystic kidney disease in Japan

BACKGROUND

The total kidney volume (TKV) and total liver volume (TLV) increase and renal function decreases progressively in patients with autosomal dominant polycystic kidney disease (ADPKD). Somatostatin analogues, such as octreotide, reduce these increases in TKV and TLV. The aim of this study was to examine the safety of the short-term administration of octreotide long-acting release (octreotide-LAR) in a small number of cases.

METHODS

Four ADPKD patients with an estimated glomerular filtration rate (eGFR) > 45 mL/min/1.73 m(2), TKV > 1,000 mL, and TLV > 3,000 mL were enrolled. Two 20-mg octreotide-LAR intramuscular injections were repeated every 4 weeks for 24 weeks. Laboratory and clinical assessments were repeated every 4 weeks, and TKV and TLV were measured by magnetic resonance imaging before and after the study.

RESULTS

In the laboratory tests, there was no abnormal variable except for a significant decrease of alanine aminotransferase. The means of TKV and TLV decreased from 2,007 to 1,903 mL and from 9,197 to 8,866 mL, respectively, but the changes were not significant. eGFR did not change significantly. Adverse events involved loose stools in two patients, as well as injection site granuloma and abdominal pain in one patient each, which resolved spontaneously.

CONCLUSION

Octreotide-LAR may be safe and effective for preventing TKV and TLV increases (UMIN000009214).

Kidney: polycystic kidney disease

Polycystic kidney disease (PKD) is a life-threatening genetic disorder characterized by the presence of fluid-filled cysts primarily in the kidneys. PKD can be inherited as autosomal recessive (ARPKD) or autosomal dominant (ADPKD) traits. Mutations in either the PKD1 or PKD2 genes, which encode polycystin 1 and polycystin 2, are the underlying cause of ADPKD. Progressive cyst formation and renal enlargement lead to renal insufficiency in these patients, which need to be managed by lifelong dialysis or renal transplantation. While characteristic features of PKD are abnormalities in epithelial cell proliferation, fluid secretion, extracellular matrix and differentiation, the molecular mechanisms underlying these events are not understood. Here we review the progress that has been made in defining the function of the polycystins, and how disruption of these functions may be involved in cystogenesis.

A young patient with a family history of hypertension

The evaluation of causes of hypertension in young adults with a family history of hypertension needs to be methodical to identify potentially treatable causes. Renal- and renovascular imaging and measurement of plasma aldosterone and plasma renin activity are at the core of this evaluation in most patients. Pertinent aspects of hypertension in autosomal dominant polycystic kidney disease are discussed with a focus on the role of the endothelium in mediating early hypertension and a review of treatment strategies. Finally, the possibility that autosomal dominant polycystic kidney disease and primary aldosteronism are connected beyond coincidence is explored; evidence to support it is scant, although there is a likely role for aldosterone excess and the resultant hypokalemia in promoting cyst growth.

Predictors of autosomal dominant polycystic kidney disease progression

Autosomal dominant polycystic kidney disease is a genetic disorder associated with substantial variability in its natural course within and between affected families. Understanding predictors for rapid progression of this disease has become increasingly important with the emergence of potential new treatments. This systematic review of the literature since 1988 evaluates factors that may predict and/or effect autosomal dominant polycystic kidney disease progression. Predicting factors associated with early adverse structural and/or functional outcomes are considered. These factors include PKD1 mutation (particularly truncating mutation), men, early onset of hypertension, early and frequent gross hematuria, and among women, three or more pregnancies. Increases in total kidney volume and decreases in GFR and renal blood flow greater than expected for a given age also signify rapid disease progression. Concerning laboratory markers include overt proteinuria, macroalbuminuria, and perhaps, elevated serum copeptin levels in affected adults. These factors and others may help to identify patients with autosomal dominant polycystic kidney disease who are most likely to benefit from early intervention with novel treatments.

Hypertension and left ventricular hypertrophy in autosomal dominant polycystic kidney disease

Hypertension is a common problem in patients with autosomal dominant polycystic kidney disease affecting both renal and patient survival. Activation of the renin-angiotensin-aldosterone system due to cyst expansion and local renal ischemia has been proposed to play an important role in the development of hypertension in autosomal dominant polycystic kidney disease. Left ventricular hypertrophy, a major cardiovascular risk factor, is also common in patients with autosomal dominant polycystic kidney disease. Both hypertension and the activation of the renin-angiotensin-aldosterone system play a role in the development of left ventricular hypertrophy in these patients. Prospective randomized results indicate that aggressive control of blood pressure is important for the optimal reversal of left ventricular hypertrophy, thereby diminishing a major risk factor for cardiovascular morbidity and mortality of patients with autosomal dominant polycystic kidney disease. There is also substantial epidemiological support for aggressive control of blood pressure in slowing renal disease progression in autosomal dominant polycystic kidney disease patients. Blockade of the renin-angiotensin-aldosterone system should be the initial approach in the treatment of hypertension in these patients.

The TRPP subfamily and polycystin-1 proteins

It has been exciting times since the identification of polycystic kidney disease 1 (PKD1) and PKD2 as the genes mutated in autosomal dominant polycystic kidney disease (ADPKD). Biological roles of the encoded proteins polycystin-1 and TRPP2 have been deduced from phenotypes in ADPKD patients, but recent insights from vertebrate and invertebrate model organisms have significantly expanded our understanding of the physiological functions of these proteins. The identification of additional TRPP (TRPP3 and TRPP5) and polycystin-1-like proteins (PKD1L1, PKD1L2, PKD1L3, and PKDREJ) has added yet another layer of complexity to these fascinating cellular signalling units. TRPP proteins assemble with polycystin-1 family members to form receptor-channel complexes. These protein modules have important biological roles ranging from tubular morphogenesis to determination of left-right asymmetry. The founding members of the polycystin family, TRPP2 and polycystin-1, are a prime example of how studying human disease genes can provide insights into fundamental biological mechanisms using a so-called "reverse translational" approach (from bedside to bench). Here, we discuss the current literature on TRPP ion channels and polycystin-1 family proteins including expression, structure, physical interactions, physiology, and lessons from animal model systems and human disease.

Renal replacement therapy in ADPKD patients: a 25-year survey based on the Catalan registry

Background

Some 7-10% of patients on replacement renal therapy (RRT) are receiving it because of autosomal dominant polycystic kidney disease (ADPKD). The age at initiation of RRT is expected to increase over time.

Methods

Clinical data of 1,586 patients (7.9%) with ADPKD and 18,447 (92.1%) patients with other nephropathies were analysed from 1984 through 2009 (1984–1991, 1992–1999 and 2000–2009).

Results

The age at initiation of RRT remained stable over the three periods in the ADPKD group (56.7 ± 10.9 (mean ± SD) vs 57.5 ± 12.1 vs 57.8 ± 13.3 years), whereas it increased significantly in the non-ADPKD group (from 54.8 ± 16.8 to 63.9 ± 16.3 years, p < 0.001). The ratio of males to females was higher for non-ADPKD than for ADPKD patients (1.6–1.8 vs 1.1–1.2). The prevalence of diabetes was significantly lower in the ADPKD group (6.76% vs 11.89%, p < 0.001), as were most of the co-morbidities studied, with the exception of hypertension. The survival rate of the ADPKD patients on RRT was higher than that of the non-ADPKD patients (p < 0.001).

Conclusions

Over time neither changes in age nor alterations in male to female ratio have occurred among ADPKD patients who have started RRT, probably because of the impact of unmodifiable genetic factors in the absence of a specific treatment.

The natural history of autosomal dominant polycystic kidney disease: 30-year experience from a single centre

BACKGROUND AND AIM

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease. The major objective of this study was to analyse the natural history of disease progression in all patients with ADPKD seen at the Sheffield Kidney Institute between 1978 and 2012.

METHODS

A retrospective analysis was performed based on recorded renal function up to 30 years prior to analysis. The rate of estimated glomerular filtration rate (eGFR) decline (ΔeGFR) was determined by linear regression, based on a minimum of 5 years of renal function prior to the study or renal replacement therapy. Patients who had reached end-stage renal disease (ESRD) (n = 113) were compared with those under follow-up in a dedicated polycystic kidney disease (PKD) clinic (n = 88).

RESULTS

The two groups were comparable in age and gender though the mean follow-up duration was longer in the PKD clinic group. Overall, ΔeGFR was significantly higher in the ESRD group compared with the PKD clinic group (4.19 ± 1.66 vs. 1.71 ± 1.36 ml/min/1.73 m(2)/year). Retrospective analysis for each 5-year period prior to ESRD or analysis showed a significant difference in ΔeGFR between both groups 10 years before with an increasing trend in ΔeGFR 20 years before especially in the ESRD group. In the PKD clinic group, the age of diagnosis and mean kidney length were also predictors of ΔeGFR.

CONCLUSION

This is one of the longest natural history studies in ADPKD. The difference in ΔeGFR can be predicted at least 10 years prior to the onset of ESRD and thus will enable higher risk patients to be identified early for treatment.

Hypertension in autosomal-dominant polycystic kidney disease (ADPKD)

Cardiovascular (CV) complications are the major cause of death in autosomal-dominant polycystic kidney disease (ADPKD) patients. Hypertension is common in these patients even before the onset of renal insufficiency. Blood pressure (BP) elevation is a key factor in patient outcome, mainly owing to the high prevalence of target organ damage together with a poor renal prognosis when BP is increased. Many factors have been implicated in the pathogenesis of hypertension, including the renin–angiotensin–aldosterone system (RAAS) stimulation. Polycystin deficiency may also contribute to hypertension because of its potential role in regulating the vascular tone. Early diagnosis and treatment of hypertension improve the CV and renal complications of this population. Ambulatory BP monitoring is recommended for prompt diagnosis of hypertension. CV risk assessment is mandatory. Even though a nonpharmacological approach should not be neglected, RAAS inhibitors are the cornerstone of hypertension treatment. Calcium channel blockers (CCBs) should be avoided unless resistant hypertension is present. The BP should be <140/90 mmHg in all ADPKD patients and a more intensive control (<135/85 mmHg) should be pursued as soon as microalbuminuria or left ventricle hypertrophy is present.

Automatic 3D Segmentation of the Kidney in MR Images Using Wavelet Feature Extraction and Probability Shape Model

Numerical estimation of the size of the kidney is useful in evaluating conditions of the kidney, especially, when serial MR imaging is performed to evaluate the kidney function. This paper presents a new method for automatic segmentation of the kidney in three-dimensional (3D) MR images, by extracting texture features and statistical matching of geometrical shape of the kidney. A set of Wavelet-based support vector machines (W-SVMs) is trained on the MR images. The W-SVMs capture texture priors of MRI for classification of the kidney and non-kidney tissues in different zones around the kidney boundary. In the segmentation procedure, these W-SVMs are trained to tentatively label each voxel around the kidney model as a kidney or non-kidney voxel by texture matching. A probability kidney model is created using 10 segmented MRI data. The model is initially localized based on the intensity profiles in three directions. The weight functions are defined for each labeled voxel for each Wavelet-based, intensity-based, and model-based label. Consequently, each voxel has three labels and three weights for the Wavelet feature, intensity, and probability model. Using a 3D edge detection method, the model is re-localized and the segmented kidney is modified based on a region growing method in the model region. The probability model is re-localized based on the results and this loop continues until the segmentation converges. Experimental results with mouse MRI data show the good performance of the proposed method in segmenting the kidney in MR images.

Type of PKD1 mutation influences renal outcome in ADPKD

Autosomal dominant polycystic kidney disease (ADPKD) is heterogeneous with regard to genic and allelic heterogeneity, as well as phenotypic variability. The genotype-phenotype relationship in ADPKD is not completely understood. Here, we studied 741 patients with ADPKD from 519 pedigrees in the Genkyst cohort and confirmed that renal survival associated with PKD2 mutations was approximately 20 years longer than that associated with PKD1 mutations. The median age at onset of ESRD was 58 years for PKD1 carriers and 79 years for PKD2 carriers. Regarding the allelic effect on phenotype, in contrast to previous studies, we found that the type of PKD1 mutation, but not its position, correlated strongly with renal survival. The median age at onset of ESRD was 55 years for carriers of a truncating mutation and 67 years for carriers of a nontruncating mutation. This observation allows the integration of genic and allelic effects into a single scheme, which may have prognostic value.

Surgical cyst decortication in autosomal dominant polycystic kidney disease

PURPOSE

To provide a summary of the relevant literature regarding the impact of surgical cyst decortication on hypertension, renal function, and pain management in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Data collection was conducted via a Medline search using the subject headings autosomal dominant polycystic kidney disease, surgery, decortication, and marsupialization. Additional reports were derived from references included within these articles.

RESULTS

Despite a trend for improved blood pressure control after cyst decortication in some studies, this cumulative review of the literature did not provide consistent evidence supporting the role of this procedure in blood pressure management in patients with ADPKD. Surgical cyst decortication was associated with renal deterioration in a subset of patients with compromised baseline renal function but did not otherwise appear to have a significant impact on renal function in the majority of studies reviewed. Improvement in chronic pain after this procedure was ubiquitously reported across all studies examined.

CONCLUSIONS

Despite a potential role in blood pressure management in the setting of ADPKD, surgical cyst decortication has not been definitively shown to alleviate hypertension in this clinical setting. Renal function does not appear to improve following this surgery. Patients with compromised baseline renal function appear to be at increased risk for further deterioration in renal function after cyst decortication, although the role of this procedure in altering the natural trajectory of renal failure in this patient subset needs further investigation. Cyst decortication is highly effective in the management of disease-related chronic pain for the majority of patients with ADPKD, providing durable pain relief in this patient population.

Urinary proteomic biomarkers for diagnosis and risk stratification of autosomal dominant polycystic kidney disease: a multicentric study

Treatment options for autosomal dominant polycystic kidney disease (ADPKD) will likely become available in the near future, hence reliable diagnostic and prognostic biomarkers for the disease are strongly needed. Here, we aimed to define urinary proteomic patterns in ADPKD patients, which aid diagnosis and risk stratification. By capillary electrophoresis online coupled to mass spectrometry (CE-MS), we compared the urinary peptidome of 41 ADPKD patients to 189 healthy controls and identified 657 peptides with significantly altered excretion, of which 209 could be sequenced using tandem mass spectrometry. A support-vector-machine based diagnostic biomarker model based on the 142 most consistent peptide markers achieved a diagnostic sensitivity of 84.5% and specificity of 94.2% in an independent validation cohort, consisting of 251 ADPKD patients from five different centers and 86 healthy controls. The proteomic alterations in ADPKD included, but were not limited to markers previously associated with acute kidney injury (AKI). The diagnostic biomarker model was highly specific for ADPKD when tested in a cohort consisting of 481 patients with a variety of renal and extrarenal diseases, including AKI. Similar to ultrasound, sensitivity and specificity of the diagnostic score depended on patient age and genotype. We were furthermore able to identify biomarkers for disease severity and progression. A proteomic severity score was developed to predict height adjusted total kidney volume (htTKV) based on proteomic analysis of 134 ADPKD patients and showed a correlation of r = 0.415 (p<0.0001) with htTKV in an independent validation cohort consisting of 158 ADPKD patients. In conclusion, the performance of peptidomic biomarker scores is superior to any other biochemical markers of ADPKD and the proteomic biomarker patterns are a promising tool for prognostic evaluation of ADPKD.

Epidemiology of autosomal-dominant polycystic kidney disease: an in-depth clinical study for south-western Germany

BACKGROUND

As we emerge into the genomic medicine era, the epidemiology of diseases is taken for granted. Accurate prevalence figures, especially of rare diseases (RDs, ≤50/100,000), will become even more important for purposes of health care and societal planning. We noticed that the numbers of affected individuals in regionally established registries for mainly hereditary RDs do not align with published estimated and expected prevalence figures. We therefore hypothesized that such non-population-based means overestimate RDs and sought to address this by recalculating prevalence for an important 'common' hereditary disease, autosomal-dominant polycystic kidney disease (ADPKD) whereby presumed-prevalence is 100-250/100,000 METHODS: The Else-Kroener-Fresenius-ADPKD-Study in south-west Germany with a population of 2,727,351 inhabitants was established with the cooperation of all nephrology centres. Furthermore, general practitioners, internists, urologists, human geneticists and neurosurgery centres were contacted with questionnaires for demographic, family and kidney function data. Germline-mutation screening of susceptibility genes PKD1 and PKD2 was offered. Official population data for 2010 were used for overall and kidney function-adjusted prevalence estimations.

RESULTS

A total of 891 subjects, 658 index-cases and 233 relatives, aged 10-89 (mean 52), were registered, with >90% response rate, 398 by nephrologists and 493 by non-nephrologists. Molecular-genetic analyses contributed to confirmation of the diagnosis in 57%. The overall prevalence of ADPKD was 32.7/100,000 reaching a maximum of 57.3/100,000 in the 6th decade of life.

CONCLUSIONS

Prevalence of ADPKD is overestimated by 2- to 5-fold and close to the limit of RDs which may be of broad clinical, logistic and policy implications.

Chronic asymptomatic pyuria precedes overt urinary tract infection and deterioration of renal function in autosomal dominant polycystic kidney disease

BACKGROUND

Urinary tract infection (UTI) occurs in 30%-50% of individuals with autosomal dominant polycystic kidney disease (ADPKD). However, the clinical relevance of asymptomatic pyuria in ADPKD patients remains unknown.

METHODS

We retrospectively reviewed medical records of 256 ADPKD patients who registered to the ADPKD clinic at Seoul National University Hospital from Aug 1999 to Aug 2010. We defined the asymptomatic pyuria as more than 5-9 white blood cells in high-power field with no related symptoms or signs of overt UTI. Patients were categorized into 2 groups depending on its duration and frequency: Group A included non-pyuria and transient pyuria patients; Group B included recurrent and persistent pyuria patients. The association between asymptomatic pyuria and both the development of overt UTI and the deterioration of renal function were examined.

RESULTS

With a mean follow-up duration of 65.3 months, 176 (68.8%) out of 256 patients experienced 681 episodes of asymptomatic pyuria and 50 episodes of UTI. The annual incidence of asymptomatic pyuria was 0.492 episodes/patient/year. The patients in group B showed female predominance (58.5% vs. 42.0%, P=0.01) and experienced an upper UTI more frequently (hazard ratio: 4.612, 95% confidence interval: 1.735-12.258; P=0.002, adjusted for gender and hypertension). The annual change in estimated glomerular filtration rate (ΔeGFR) was significantly larger in magnitude in group B than in group A (-2.7±4.56 vs. -1.17±5.8, respectively; P=0.01). Age and Group B found to be the independent variables for ΔeGFR and developing end-stage renal disease (16.0% vs. 4.3%, respectively; P=0.001).

CONCLUSIONS

Chronic asymptomatic pyuria may increase the risk of developing overt UTI and may contribute to declining renal function in ADPKD.

Chronic asymptomatic pyuria precedes overt urinary tract infection and deterioration of renal function in autosomal dominant polycystic kidney disease

BACKGROUND

Urinary tract infection (UTI) occurs in 30%-50% of individuals with autosomal dominant polycystic kidney disease (ADPKD). However, the clinical relevance of asymptomatic pyuria in ADPKD patients remains unknown.

METHODS

We retrospectively reviewed medical records of 256 ADPKD patients who registered to the ADPKD clinic at Seoul National University Hospital from Aug 1999 to Aug 2010. We defined the asymptomatic pyuria as more than 5-9 white blood cells in high-power field with no related symptoms or signs of overt UTI. Patients were categorized into 2 groups depending on its duration and frequency: Group A included non-pyuria and transient pyuria patients; Group B included recurrent and persistent pyuria patients. The association between asymptomatic pyuria and both the development of overt UTI and the deterioration of renal function were examined.

RESULTS

With a mean follow-up duration of 65.3 months, 176 (68.8%) out of 256 patients experienced 681 episodes of asymptomatic pyuria and 50 episodes of UTI. The annual incidence of asymptomatic pyuria was 0.492 episodes/patient/year. The patients in group B showed female predominance (58.5% vs. 42.0%, P=0.01) and experienced an upper UTI more frequently (hazard ratio: 4.612, 95% confidence interval: 1.735-12.258; P=0.002, adjusted for gender and hypertension). The annual change in estimated glomerular filtration rate (ΔeGFR) was significantly larger in magnitude in group B than in group A (-2.7±4.56 vs. -1.17±5.8, respectively; P=0.01). Age and Group B found to be the independent variables for ΔeGFR and developing end-stage renal disease (16.0% vs. 4.3%, respectively; P=0.001).

CONCLUSIONS

Chronic asymptomatic pyuria may increase the risk of developing overt UTI and may contribute to declining renal function in ADPKD.

Nephrotic syndrome and autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder characterized by the development and growth of cysts in the kidneys and other organs. In ADPKD patients, nephrotic range proteinuria is unusual and needs to be investigated further to exclude coexisting glomerular disease. Among the anecdotal case reports of ADPKD associated with nephrotic syndrome, focal segmental glomerulosclerosis occurs most frequently.

METHODS

We report the case of a 26-year-old male with ADPKD and concomitant nephrotic syndrome, in which an ultrasound (US)-guided renal biopsy showed a mesangioproliferative glomerulonephritis. We treated the patient with prednisone 1 mg/kg/day, because of the failure of treatment with angiotensin-converting enzyme inhibitor/angiotensin receptor blocker association.

RESULTS

After 6 months of steroid treatment, we observed a stability of his GFR and a reduction of proteinuria.

CONCLUSION

This case report and other cases of the literature underline the importance of a renal biopsy in patients with ADPKD and nephrotic syndrome in order to make an accurate diagnosis and an appropriate treatment/prevention of renal function deterioration.

Intraobserver and interobserver variability of renal volume measurements in polycystic kidney disease using a semiautomated MR segmentation algorithm

OBJECTIVE

Total renal volume and changes in kidney volume are markers of disease progression in autosomal-dominant polycystic kidney disease (ADPKD) but are not used in clinical practice in part because of the complexity of manual measurements. This study aims to assess the intra- and interobserver reproducibility of a semiautomated renal volumetric algorithm using fluid-sensitive MRI pulse sequences.

SUBJECTS AND METHODS

Renal volumes of 17 patients with ADPKD were segmented from high-resolution coronal HASTE and true fast imaging with steady-state precession (FISP) MR acquisitions. Measurements performed independently by four readers were repeated, typically after 7 days. Intraobserver agreement indexes were calculated for total kidney volume for each patient. Interobserver agreement indexes were obtained for the six paired combinations of readers as well as for two readers after rigorous formalized training. Pearson and concordance correlation coefficients, coefficients of variation (CVs), and 95% limits of agreement were determined.

RESULTS

The HASTE and true FISP sequences performed similarly with a median intraobserver agreement of greater than 98.1% and a CV of less than 2.4% across all readers. The median interobserver agreement was greater than 95.2% and the CV was less than 7.1%, across all reader pairs. Reader training further lowered interobserver CV. The mean total kidney volume was 1420 mL (range, 331-3782 mL) for HASTE imaging and 1445 mL (range, 301-3714 mL) for true FISP imaging, with mean image processing times per patient of 43 and 28 minutes, respectively.

CONCLUSION

This semiautomated MR volumetric algorithm provided excellent intraobserver and very good interobserver reproducibility using fluid-sensitive pulse sequences that emphasize cyst conspicuity.

Timing and outcome of renal replacement therapy in patients with congenital malformations of the kidney and urinary tract

BACKGROUND AND OBJECTIVES

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of ESRD in children, but the proportion of patients with individual CAKUT entities progressing to ESRD during adulthood and their long-term clinical outcomes are unknown. This study assessed the age at onset of renal replacement therapy (RRT) and patient and renal graft survival in patients with CAKUT across the entire age range.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with CAKUT were compared with age-matched patients who were undergoing RRT for other renal disorders on the basis of data from the European Renal Association-European Dialysis and Transplant Association Registry. Competing risk and Cox regression analyses were conducted.

RESULTS

Of 212,930 patients commencing RRT from 1990 to 2009, 4765 (2.2%) had renal diagnoses consistent with CAKUT. The proportion of incident RRT patients with CAKUT decreased from infancy to childhood and then increased until age 15-19 years, followed by a gradual decline throughout adulthood. Median age at RRT start was 31 years in the CAKUT cohort and 61 years in the non-CAKUT cohort (P<0.001). RRT was started earlier (median, 16 years) in patients with isolated renal dysplasia than in those with renal hypoplasia and associated urinary tract disorders (median, 29.5-39.5 years). Patients with CAKUT survived longer than age- and sex-matched non-CAKUT controls because of lower cardiovascular mortality (10-year survival rate, 76.4% versus 70.7%; P<0.001).

CONCLUSIONS

CAKUT leads to ESRD more often at adult than pediatric age. Treatment outcomes differ from those of acquired kidney diseases and vary within CAKUT subcategories.

Prevalence of cardiovascular events in patients with autosomal dominant polycystic kidney disease

BACKGROUND

This study evaluates the prevalence of cardiovascular events in autosomal dominant polycystic kidney disease (ADPKD) patients.

METHODS

We distributed surveys to 1,439 subjects from our ADPKD research database. In total, 426 subjects completed and returned surveys; 7 of these were from children and were excluded from the study.

RESULTS

The patients who responded were female (63.2%), nonHispanic (88.1%) and white (93.6%). The mean age of the total group was 53.2 ± 13.7 years; 82.8% had a family history of ADPKD and 32.5% had reached end-stage renal disease (ESRD). With respect to cardiovascular risk factors, 86.6% were hypertensive with a mean age at diagnosis of 36.9 ± 12.9 years and hypertension was significantly more prevalent in males. In addition, 19.6% of the subjects were obese, 20.8% were smokers, 8.7% had diabetes, 45.7% had high cholesterol and 17.8% were sedentary. The most prevalent self-reported cardiovascular events were arrhythmias (25.9%), evidence of peripheral vascular disease (16.5%), heart valve problems (14.4%), cardiac enlargement (9.5%), stroke or cerebral bleeding (7.5%), myocardial infarction (6%) and brain aneurysm (5.0%). The most commonly used antihypertensive medications were renin-angiotensin inhibitors used by 75% of ADPKD patients. Older ADPKD patients and those at ESRD had a significantly higher incidence of cardiovascular events.

CONCLUSION

These findings support the high prevalence of cardiovascular risk factors and events in ADPKD patients which contribute to a greater mortality risk. Due to the prevalence of cardiovascular risk factors in the ADPKD population, early diagnosis and clinical intervention are recommended.

Polycystin-1 regulates the stability and ubiquitination of transcription factor Jade-1

Autosomal-dominant polycystic kidney disease (ADPKD) and von Hippel-Lindau (VHL) disease lead to large kidney cysts that share pathogenetic features. The polycystin-1 (PC1) and pVHL proteins may therefore participate in the same key signaling pathways. Jade-1 is a pro-apoptotic and growth suppressive ubiquitin ligase for beta-catenin and transcriptional coactivator associated with histone acetyltransferase activity that is stabilized by pVHL in a manner that correlates with risk of VHL renal disease. Thus, a relationship between Jade-1 and PC1 was sought. Full-length PC1 bound, stabilized and colocalized with Jade-1 and inhibited Jade-1 ubiquitination. In contrast, the cytoplasmic tail or the naturally occurring C-terminal fragment of PC1 (PC1-CTF) promoted Jade-1 ubiquitination and degradation, suggesting a dominant-negative mechanism. ADPKD-associated PC1 mutants failed to regulate Jade-1, indicating a potential disease link. Jade-1 ubiquitination was mediated by Siah-1, an E3 ligase that binds PC1. By controlling Jade-1 abundance, PC1 and the PC1-CTF differentially regulate Jade-1-mediated transcriptional activity. A key target of PC1, the cyclin-dependent kinase inhibitor p21, is also up-regulated by Jade-1. Through Jade-1, PC1 and PC1 cleaved forms may exert fine control of beta-catenin and canonical Wnt signaling, a critical pathway in cystic renal disease. Thus, Jade-1 is a transcription factor and ubiquitin ligase whose activity is regulated by PC1 in a manner that is physiologic and may correlate with disease. Jade-1 may be an important therapeutic target in renal cystogenesis.

Emergent early markers of renal progression in autosomal-dominant polycystic kidney disease patients: implications for prevention and treatment

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common single cause of end-stage renal disease after diabetes, hypertension and glomerulonephritis. The clinical course of ADPKD is highly variable. Even with optimal care and therapy monitoring, currently the progression of ADPKD is slowed but not stopped. Newer treatments will no doubt become available in the future, but their side effect profiles will always need to be considered. Therefore, markers to distinguish ADPKD patients with a poor versus a good prognosis will be helpful. Several risk factors influencing kidney disease progression in ADPKD have been identified in the current era. The present review will discuss the spectrum of early markers of ADPKD renal disease progression. Specifically, the volume of total kidney, hypertension, glomerular hyperfiltration, renal blood flow, microalbuminuria, uric acid, and urinary molecular markers will be discussed. On this background, implications for the prevention and treatment of kidney disease progression in ADPKD are also discussed.

Low birth weight is associated with earlier onset of end-stage renal disease in Danish patients with autosomal dominant polycystic kidney disease

Low-birth-weight individuals have a higher risk of hypertension and end-stage renal disease (ESRD). Here we investigated whether low birth weight was associated with earlier onset of ESRD in patients with autosomal dominant polycystic kidney disease (ADPKD). In collaboration with all Danish departments of nephrology, 307 of 357 patients with ADPKD and ESRD born and living in Denmark were recruited. We were able to analyze complete data of 284 patients obtained from both hospital medical files and midwife protocols in the Danish State Archives. Multivariable linear regression adjusted for birth weight, adult height, mean arterial pressure, gender, birth decade, and type of antihypertensive treatment showed that for every kilogram increase in birth weight, the age at onset of ESRD significantly increased by 1.7 years. Male gender and increased mean arterial pressure were both associated with earlier onset of ESRD. Patients treated with renin-angiotensin system blockade or calcium channel blockers during follow-up had significantly later onset of ESRD by 4.3 years and 2.1 years, respectively. Treatment with beta-blockade or a diuretic was not associated with the age at onset of ESRD. Thus, low birth weight may contribute to considerable phenotypic variability in the progression of renal disease between individuals with ADPKD.

Dissecting aneurysm in a patient with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is primarily associated with renal failure, but it also causes systemic diseases, including cysts of other systemic organs and cerebral or visceral aneurysm. To make matters worse, life-threatening aortic diseases are associated with ADPKD in some cases. However, only a few reports of ADPKD-associated with thoracic aortic dissection have been published. Herein, we present a case of dissecting aneurysm in a patient with hypertension and ADPKD. He had been followed up for type B aortic dissection for six years. Preoperative creatinine level ranged from 2.1 to 2.4 mg/dl. We performed replacement of the thoracic aorta with prosthetic graft successfully, and postoperatively, dialysis was not required.It is very important for us to recognize the relationship between ADPKD and thoracic aortic dissection, which can cause high mortality and morbidity rates.

Educational paper: ciliopathies

Cilia are antenna-like organelles found on the surface of most cells. They transduce molecular signals and facilitate interactions between cells and their environment. Ciliary dysfunction has been shown to underlie a broad range of overlapping, clinically and genetically heterogeneous phenotypes, collectively termed ciliopathies. Literally, all organs can be affected. Frequent cilia-related manifestations are (poly)cystic kidney disease, retinal degeneration, situs inversus, cardiac defects, polydactyly, other skeletal abnormalities, and defects of the central and peripheral nervous system, occurring either isolated or as part of syndromes. Characterization of ciliopathies and the decisive role of primary cilia in signal transduction and cell division provides novel insights into tumorigenesis, mental retardation, and other common causes of morbidity and mortality, including diabetes mellitus and obesity. New technologies ("Next generation sequencing/NGS") have considerably improved genetic research and diagnostics by allowing simultaneous investigation of all disease genes at reduced costs and lower turn-around times. This is undoubtedly a result of the dynamic development in the field of human genetics and deserves increased attention in genetic counselling and the management of affected families.

Analysis of baseline parameters in the HALT polycystic kidney disease trials

HALT PKD consists of two ongoing randomized trials with the largest cohort of systematically studied patients with autosomal dominant polycystic kidney disease to date. Study A will compare combined treatment with an angiotensin-converting inhibitor and receptor blocker to inhibitor alone and standard compared with low blood pressure targets in 558 early-stage disease patients with an eGFR over 60 ml/min per 1.73 m(2). Study B will compare inhibitor-blocker treatment to the inhibitor alone in 486 late-stage patients with eGFR 25-60 ml/min per 1.73 m(2). We used correlation and multiple regression cross-sectional analyses to determine associations of baseline parameters with total kidney, liver, or liver cyst volumes measured by MRI in Study A and eGFR in both studies. Lower eGFR and higher natural log-transformed urine albumin excretion were independently associated with a larger natural log-transformed total kidney volume adjusted for height (ln(HtTKV)). Higher body surface area was independently associated with a higher ln(HtTKV) and lower eGFR. Men had larger height-adjusted total kidney volume and smaller liver cyst volumes than women. A weak correlation was found between the ln(HtTKV) and natural log-transformed total liver volume adjusted for height or natural log liver cyst volume in women only. Women had higher urine aldosterone excretion and lower plasma potassium. Thus, our analysis (1) confirms a strong association between renal volume and functional parameters, (2) shows that gender and other factors differentially affect the development of polycystic disease in the kidney and liver, and (3) suggests an association between anthropomorphic measures reflecting prenatal and/or postnatal growth and disease severity.

2-Hydroxyestradiol slows progression of experimental polycystic kidney disease

Male gender is a risk factor for progression of polycystic kidney disease (PKD). 17β-Estradiol (E2) protects experimentally, but clinical use is limited by adverse effects. Novel E2 metabolites provide many benefits of E2 without stimulating the estrogen receptor, and thus may be safer. We hypothesized that E2 metabolites are protective in a model of PKD. Studies were performed in male control Han:SPRD rats, and in cystic males treated with orchiectomy, 2-methoxyestradiol, 2-hydroxyestradiol (2-OHE), or vehicle, from age 3 to 12 wk. Cystic rats exhibited renal functional impairment (∼50% decrease in glomerular filtration and renal plasma flow rates, P < 0.05) and substantial cyst development (20.5 ± 2.0% of cortex area). 2-OHE was the most effective in limiting cysts (6.0 ± 0.7% of cortex area, P < 0.05 vs. vehicle-treated cystic rats) and preserving function, in association with suppression of proliferation, apoptosis, and angiogenesis markers. Downregulation of p21 expression and increased expression of Akt, the mammalian target of rapamycin (mTOR), and some of its downstream effectors were significantly reversed by 2-OHE. Thus, 2-OHE limits disease progression in a cystic rodent model. Mechanisms include reduced renal cell proliferation, apoptosis, and angiogenesis. These effects may be mediated, at least in part, by preservation of p21 and suppression of Akt and mTOR. Estradiol metabolites may represent a novel, safe intervention to slow progression of PKD.

Glomerular hyperfiltration and renal progression in children with autosomal dominant polycystic kidney disease

BACKGROUND AND OBJECTIVES

The purpose of this study was to determine whether glomerular hyperfiltration (GH) occurring early in autosomal dominant polycystic kidney disease (ADPKD) is indicative of more rapid disease progression in children.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

One hundred eighty children with ADPKD (ages 4 to 18 years) with normal renal function were examined by renal ultrasound. Renal volume was calculated using a standard formula for a modified ellipsoid. Creatinine clearance was calculated from serum creatinine and 24-hour urine creatinine. GH was defined as creatinine clearance ≥140 ml/min per 1.73 m(2).

RESULTS

Thirty-two children had GH (mean age 11.4 ± 3.6 years) and 148 had normal renal function (mean age 10.8 ± 3.9 years). Patients with GH at baseline demonstrated an increased rate of total renal volume growth (β: rate of change = +19.3 ± 10.8 cm(3)/year) over 5 years compared with those without GH at baseline (β = -4.3 ± 7.7 cm(3)/year), P = 0.008. Those with GH at baseline experienced a faster decline in creatinine clearance in subsequent years (β = -5.0 ± 0.8 ml/min per 1.73 m(2) per year) compared with those without GH at baseline (β = +1.0 ± 0.4 ml/min per 1.73 m(2) per year), P < 0.0001.

CONCLUSIONS

This study revealed that occurrence of GH in ADPKD children is associated with a significantly faster decline in renal function and higher rate of kidney enlargement over time. GH combined with the increased renal volume may therefore be used as an early marker for a more severe progression of ADPKD in children.

Why kidneys fail in autosomal dominant polycystic kidney disease

The weight of evidence gathered from studies in humans with hereditary polycystic kidney disease (PKD)1 and PKD2 disorders, as well as from experimental animal models, indicates that cysts are primarily responsible for the decline in glomerular filtration rate that occurs fairly late in the course of the disease. The processes underlying this decline include anatomic disruption of glomerular filtration and urinary concentration mechanisms on a massive scale, coupled with compression and obstruction by cysts of adjacent nephrons in the cortex, medulla and papilla. Cysts prevent the drainage of urine from upstream tributaries, which leads to tubule atrophy and loss of functioning kidney parenchyma by mechanisms similar to those found in ureteral obstruction. Cyst-derived chemokines, cytokines and growth factors result in a progression to fibrosis that is comparable with the development of other progressive end-stage renal diseases. Treatment of renal cystic disorders early enough to prevent or reduce cyst formation or slow cyst growth, before the secondary changes become widespread, is a reasonable strategy to prolong the useful function of kidneys in patients with autosomal dominant polycystic kidney disease.

Intermediate volume on computed tomography imaging defines a fibrotic compartment that predicts glomerular filtration rate decline in autosomal dominant polycystic kidney disease patients

Total kidney and cyst volumes have been used to quantify disease progression in autosomal dominant polycystic kidney disease (ADPKD), but a causal relationship with progression to renal failure has not been demonstrated. Advanced image processing recently allowed to quantify extracystic tissue, and to identify an additional tissue component named "intermediate," appearing hypoenhanced on contrast-enhanced computed tomography (CT). The aim of this study is to provide a histological characterization of intermediate volume, investigate its relation with renal function, and provide preliminary evidence of its role in long-term prediction of functional loss. Three ADPKD patients underwent contrast-enhanced CT scans before nephrectomy. Histological samples of intermediate volume were drawn from the excised kidneys, and stained with hematoxylin and eosin and with saturated picrosirius solution for histological analysis. Intermediate volume showed major structural changes, characterized by tubular dilation and atrophy, microcysts, inflammatory cell infiltrate, vascular sclerosis, and extended peritubular interstitial fibrosis. A significant correlation (r = -0.69, P < 0.001) between relative intermediate volume and baseline renal function was found in 21 ADPKD patients. Long-term prediction of renal functional loss was investigated in an independent cohort of 13 ADPKD patients, followed for 3 to 8 years. Intermediate volume, but not total kidney or cyst volume, significantly correlated with glomerular filtration rate decline (r = -0.79, P < 0.005). These findings suggest that intermediate volume may represent a suitable surrogate marker of ADPKD progression and a novel therapeutic target.

Diagnosis and management of childhood polycystic kidney disease

A number of syndromic disorders have renal cysts as a component of their phenotypes. These disorders can generally be distinguished from autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) by imaging studies of their characteristic, predominantly non-renal associated abnormalities. Therefore, a major distinction in the differential diagnosis of enlarge echogenic kidneys is delineating ARPKD from ADPKD. ADPKD and ARPKD can be diagnosed by imaging the kidney with ultrasound, computed tomography, or magnetic resonance imaging (MRI), although ultrasound is still the method of choice for diagnosis in utero and in young children due to ease of use, cost, and safety. Differences in ultrasound characteristics, the presence or absence of associated extrarenal abnormalities, and the screening of the parents >40 years of age usually allow the clinician to make an accurate diagnosis. Early diagnosis of ADPKD and ARPKD affords the opportunity for maximal anticipatory care (i.e. blood pressure control) and in the not-too-distant future, the opportunity to benefit from new therapies currently being developed. If results are equivocal, genetic testing is available for both ARPKD and ADPKD. Specialized centers are now offering preimplantation genetic diagnosis and in vitro fertilization for parents who have previously had a child with ARPKD. For ADPKD patients, a number of therapeutic interventions are currently in clinical trial and may soon be available.

Peritoneal dialysis as the first-line renal replacement therapy in patients with autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cause of kidney failure. Peritoneal dialysis (PD) often is avoided because of concerns about hernias and peritonitis.

STUDY DESIGN

Retrospective matched-cohort study.

SETTING & PARTICIPANTS

42 consecutive patients with ADPKD and 84 nondiabetic patients matched by time of PD therapy initiation.

PREDICTORS

ADPKD and comorbid conditions.

OUTCOMES

Patient survival, technique survival, peritonitis-free survival; peritonitis rate; abdominal hernias.

MEASUREMENTS

Dialysis adequacy and nutritional indexes; rate of decrease in residual renal function; bacteriologic cause of peritonitis.

RESULTS

5-year actuarial survival of the ADPKD and control groups was 71.0% and 69.7% (P = 0.4), whereas technique survival was 51.6% and 37.3%, respectively (P = 0.2). There was no difference in overall rates of peritonitis between the ADPKD and control groups (0.51 vs 0.53 episodes/patient-year; P = 0.3), and the incidence of Gram-negative peritonitis also was similar (0.16 vs 0.14 episodes/patient year; P = 0.5). Abdominal wall hernia was significantly more common in the ADPKD than control group (14 vs 6 cases; P < 0.001), but all patients were able to resume PD therapy after surgical repair.

LIMITATIONS

Retrospective study with limited sample size.

CONCLUSION

PD is a feasible treatment option for most patients with ADPKD with end-stage renal disease. Although patients with ADPKD have a higher risk of abdominal wall hernia, their overall survival rate and risk of peritonitis are similar to those of other nondiabetic PD patients.

The relationship between renal volume and renal function in autosomal dominant polycystic kidney disease

BACKGROUND

In patients with autosomal dominant polycystic kidney disease (ADPKD), renal cysts grow exponentially. Since remaining renal parenchyma has a capacity to compensate for the loss of glomerular filtration, the glomerular filtration rate (GFR) may be sustained until the disease progresses. The purpose of this study was to determine if renal volumetric indices and clinical parameters are associated with renal function in Japanese patients with ADPKD.

METHODS

In 73 ADPKD patients (28 men, 45 women), the associations of mean systolic blood pressure, mean diastolic blood pressure, estimated GFR (eGFR), the amount of proteinuria and albuminuria, body mass index (BMI), brachial-ankle pulse wave velocity (baPWV), ankle-brachial index, and total kidney volume (TKV) were retrospectively analyzed.

RESULTS

Multivariate linear regression analysis showed that eGFR was significantly and independently inversely correlated with patients' age and BMI. The median change in eGFR per year (ΔeGFR/y) was -2.8 ml/min/1.73 m(2)/year. Multiple linear regression analysis showed that ΔeGFR/y was significantly and independently inversely correlated with the change in TKV per year (ΔTKV/y). Multiple linear regression analysis showed that ΔTKV/y was significantly related to initial TKV and the change in albuminuria per year.

CONCLUSIONS

This study demonstrated a significant relationship between the change in renal function and the change in renal volume in Japanese ADPKD patients without renal insufficiency. It is possible that the volume measurements can be used as useful markers for disease progression in Japanese ADPKD patients.

Assessment of kidney volume in polycystic kidney disease using magnetic resonance imaging without contrast medium

BACKGROUND/AIMS

Total renal volume (TRV) is an important index to evaluate the progression of autosomal-dominant polycystic kidney disease (ADPKD). TRV has been assessed by manually tracing renal contours from CT or MR scans, often employing contrast medium (CM). We developed a fast and nearly automated technique based on the analysis of MR images acquired without CM injection for TRV quantification.

METHODS

30 ADPKD patients underwent MRI. After the selection of one point inside each kidney for the entire volume, the automatic extraction of kidney contours was performed on each acquired slice; the segmentation procedure was based on region growing and on the application of morphological operators and curvature-based motion. The area inside each contour was calculated and TRV was derived. Volume measurements were validated by comparison with measurements obtained by stereology.

RESULTS

TRV estimated in patients was 768 ± 545 ml (range 161-3,111 ml). The automatic measurements were in excellent correlation with the manual ones (r = 0.99, y = x - 0.7), with a small bias and narrow limits of agreement in both absolute (-5 ± 37 ml) and percentage (-0.6 ± 9.6%) terms.

CONCLUSION

This preliminary study showed the feasibility of a fast and nearly automated method for determining TRV; importantly it does not require the use of potentially nephrotoxic CM.

Effect of statin therapy on disease progression in pediatric ADPKD: design and baseline characteristics of participants

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney condition and is associated with important renal and cardiovascular manifestations in childhood. Renal cystic disease can be documented in some cases as early as in utero. Early intervention is critical if the long-term complications of this condition, including end-stage renal disease, are to be ameliorated. Here we describe our ongoing randomized double-blind placebo-controlled phase III clinical trial to assess the effect of pravastatin treatment on renal and cardiovascular disease progression in 107 children and young adults age 8-22 years with ADPKD who are receiving the angiotensin converting enzyme inhibitor lisinopril. Baseline demographic and laboratory data are provided. Results of this study could markedly impact the standard of care for evaluation and treatment of ADPKD in this population.