Autosomal dominant polycystic kidney disease

Esophageal Artery Pseudoaneurysm and Takayasu Arteritis in a Patient with Autosomal Dominant Polycystic Kidney Disease

A 47-year-old female previously diagnosed with ADPKD visited the hospital due to sudden pain in her upper abdomen and back. Esophagogastroduodenoscopy, contrast-enhanced abdominal computed tomography (CT), and CT angiography identified an esophageal artery pseudoaneurysm and hematoma in the esophagus. Urgent angiography and embolization were performed. After the procedure, CT angiography and positron emission tomography were performed due to differences in blood pressure between the arms. The patient was also found to have Takayasu arteritis and subsequently received outpatient follow-up care. The possible mechanisms that cause vascular abnormalities in ADPKD patients include damaged vascular integrity due to abnormal polycystin expression caused by PKD mutations and connective tissue abnormalities. Further research is needed to confirm these mechanisms, and ADPKD patients should be assessed for vascular abnormalities.

Predictors and outcomes of laparoscopic nephrectomy in autosomal dominant polycystic kidney disease

Purpose

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, and 20% of patients eventually require nephrectomies due to compressive symptoms or renal-related complications. Traditionally, nephrectomies were performed via the open approach in view of space constraints. We evaluate our institution's outcomes for laparoscopic nephrectomy (LN) for ADPKD.

Materials and Methods

We retrospectively reviewed 33 patients with ADPKD who underwent nephrectomies from November 2005 to December 2016 at a tertiary institution. Preoperative kidney volume was calculated via the ellipsoid method by using computed tomography scan.

Results

The median age was 51.0 years (interquartile range [IQR], 44.5–56.0 years). Sixteen patients (48.5%) underwent open nephrectomy (ON), 15 patients (45.5%) had LNs, and 2 patients (6.1%) had laparoscopic converted to ON due to dense adhesions. Thirteen patients had bilateral while 18 patients had unilateral nephrectomies. Median kidney volume in the open group was 1,042 cm³ (IQR, 753–2,365 cm³) versus 899 cm³ (IQR, 482–1,914 cm³) in the laparoscopy group and did not differ significantly. The operative time was comparable between both groups. Patients who underwent LN had lesser blood loss (350 mL vs. 650 mL; 95% confidence interval [CI], 1.822–3.533; p=0.016) and shorter length of hospital stay (4.0 days vs. 6.5 days; 95% CI, 1.445–5.755; p=0.001) compared to patients who underwent ON. Both groups had similar low morbidity rate and no mortality.

Conclusions

LN for ADPKD is a safe and effective alternative to ON independent of kidney size with comparable outcomes and benefits of minimally invasive surgery.

A case of congenital left ventricular diverticulum in a patient with autosomal dominant polycystic kidney disease: possible mechanistic link between polycystin and ventricular diverticulum

A 40-year-old woman had been followed as an outpatient to manage chronic kidney disease secondary to autosomal dominant polycystic kidney disease (ADPKD). Atrial premature contraction was found incidentally on an electrocardiogram during her regular follow-up examination. Subsequent transthoracic echocardiography detected an abnormal structure located very close to the left ventricular outflow tract (23 mm long × 15 mm wide in diastole). The structure was finally diagnosed as congenital left ventricular diverticulum (CLVD) using transesophageal echocardiography, contrast-enhanced computed tomography, and magnetic resonance imaging. Although CLVD occasionally causes intraventricular coagulation, lethal arrhythmia, and congestive heart failure, the size and location of her diverticulum remained unchanged over time and a 24-h Holter electrocardiogram showed no lethal arrhythmias. Accordingly, neither anticoagulation therapy nor surgical resection of the diverticulum was performed. To the best of our knowledge, ours is the first case of CLVD in a patient with ADPKD. Because gene abnormalities in polycystin coding are mechanistically related to the development of colonic diverticulum and abnormal cyst formation in ADPKD patients, we suspected that CLVD and abnormal cyst formation were related to the same gene abnormality in ADPKD. More case reports, case series studies, and basic research are required to determine whether CLVD in ADPKD is mechanistically associated with abnormal polycystin or just a coincidence.

A Novel PKD1 Mutation Associated With Autosomal Dominant Kidney Disease and Cerebral Cavernous Malformation

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the presence of renal cysts and specific extrarenal abnormalities. ADPKD is caused by mutations in either PKD1 or PKD2 genes that encode for integral membrane proteins Polycystin-1 (PC1) and Polycystin-2 (PC2), respectively. Extrarenal involvement includes noncystic manifestations such as dilatation of the aortic root, artery dissection and intracranial aneurysms. Cerebral cavernous malformation (CCM) is a rare vascular malformation disorder characterized by closely clustered and irregularly dilated capillaries that can be asymptomatic or cause variable neurological manifestations, such as seizures, non-specific headaches, progressive or transient focal neurologic deficits, and cerebral hemorrhages. Familial CCM is typically associated with mutations in KRIT1 (CCM1), CCM2, and PDCD10 (CCM3). The co-occurrence of ADPKD and CCM has been previously described in a single patient, although genetic analysis was not performed in this study. We report here a family with ADPKD associated with CCM in two sisters. Direct sequencing of the index patient revealed a single novel heterozygous frameshift mutation in PKD1, and lack of mutations in genes usually related to CCM. This suggests that CCM represents an additional phenotype of ADPKD.

3DUS as an alternative to MRI for measuring renal volume in children with autosomal dominant polycystic kidney disease

BACKGROUND

Total kidney volume, measured by magnetic resonance imaging (MRI), is a validated disease progression marker in adults with autosomal dominant polycystic kidney disease (ADPKD). However, in childhood, MRI is burdensome, explaining the need for alternatives.

METHODS

Kidney volume (KV) was evaluated in 30 children with ADPKD, using three-dimensional ultrasound (3DUS), applying the ellipsoid method and manual contouring (KV_{3DUS-ellipsoid,} KV_3DUS-contour respectively); manual contouring on MRI (KV_MRI), and the ellipsoid method on two-dimensional ultrasound (2DUS, KV_2DUS). Correlations and differences were evaluated using Pearson's r and Wilcoxon signed-rank tests, and variability using Bland-Altman plots.

RESULTS

All ultrasound volumetry methods showed significantly lower mean (± SD) KV (mL), compared with MRI-KV_2DUS: 159 (±101); K_{3DUS-ellipsoid}: 169 (±105); KV_3DUS-contour: 185 (±110); KV_MRI: 206 (±130); all p < 0.001. All had a strong correlation with KV_MRI: 2DUS: r = 0.96; 3DUS-ellipsoid: r = 0.89 and 3DUS-contour: r = 0.94. Both before and after correction factor application, Bland-Altman plots showed lower variability and absolute error for KV_3DUS-contour vs KV_2DUS and KV_{3DUS-ellipsoid}.

CONCLUSIONS

Compared with MRI, ultrasound volumetry was prone to underestimation. However, KV_3DUS-contour represents a valuable alternative for MRI in early ADPKD. Although more time-consuming, KV_3DUS-contour is recommended over KV_2DUS for estimation and follow-up of KV in ADPKD children, given its smaller error.

Axial Spondyloarthritis and Autosomal Dominant Polycystic Kidney Disease in Two Siblings: A Rare Cooccurrence

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequently occurring hereditary kidney disease, and axial spondyloarthritis (SpA) is one of the most frequently occurring rheumatic diseases. Treatment-related decisions for axial SpA may pose a challenge in case of renal involvement. The authors describe two siblings with cooccurrence of these two diseases. The association of these two diseases is not well known. Practitioners should monitor renal function in SpA patients and take treatment-related decisions regarding renal involvement. Antitumor necrosis factor-alpha (anti-TNF-α) agents may be used in case nonsteroidal anti-inflammatory drugs (NSAIDs) cannot be utilized.

18F-FDG PET/CT in Autosomal Dominant Polycystic Kidney Disease Patients with Suspected Cyst Infection

The objective of this study was to determine the value of ¹⁸F-FDG PET/CT for diagnosing renal or hepatic cyst infection in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods: This retrospective, single-center study included all patients who had ADPKD and underwent ¹⁸F-FDG PET/CT because of suspected cyst infection between 2010 and 2017. Results: Thirty ¹⁸F-FDG PET/CT scans of 30 individual patients were included; 19 of them had positive results for cyst infection. According to a previously established clinical and biochemical reference standard, ¹⁸F-FDG PET/CT achieved a sensitivity of 88.9%, a specificity of 75.0%, a positive predictive value of 84.2%, and a negative predictive value of 81.8% for the diagnosis of cyst infection. In 5 cases, ¹⁸F-FDG PET/CT suggested that the symptoms could be explained by a different pathologic process, including pneumonia (n = 1), generalized peritonitis (n = 1), pancreatitis (n = 1), colitis (n = 1), and cholangitis (n = 1). The total duration of the hospital stay and the duration between the ¹⁸F-FDG PET/CT scan and hospital discharge for patients with ¹⁸F-FDG PET/CT scan results that were positive for cyst infection were significantly longer than those for patients with negative scan results (P = 0.005 and P = 0.009, respectively). Creatinine levels were significantly higher in patients with ¹⁸F-FDG PET/CT scan results that were positive for cyst infection than in patients with negative scan results (P = 0.015). Other comparisons of clinical parameters (age, sex, presence of fever [>38.5°C] for more than 3 d, abdominal pain, history of solid-organ transplantation and nephrectomy, and immune status), laboratory values (C-reactive protein level, leukocyte count, and estimated glomerular filtration rate), and microbiologic test results (blood and urine cultures) were not significantly different (P = 0.13-1.00) in patients with positive and negative ¹⁸F-FDG PET/CT scan results. Conclusion: ¹⁸F-FDG PET/CT is a useful imaging modality for the evaluation of patients with ADPKD and suspected cyst infection.

Kidney enlargement and multiple liver cyst formation implicate mutations in PKD1/2 in adult sporadic polycystic kidney disease

Distinguishing autosomal-dominant polycystic kidney disease (ADPKD) from other inherited renal cystic diseases in patients with adult polycystic kidney disease and no family history is critical for correct treatment and appropriate genetic counseling. However, for patients with no family history, there are no definitive imaging findings that provide an unequivocal ADPKD diagnosis. We analyzed 53 adult polycystic kidney disease patients with no family history. Comprehensive genetic testing was performed using capture-based next-generation sequencing for 69 genes currently known to cause hereditary renal cystic diseases including ADPKD. Through our analysis, 32 patients had PKD1 or PKD2 mutations. Additionally, 3 patients with disease-causing mutations in NPHP4, PKHD1, and OFD1 were diagnosed with an inherited renal cystic disease other than ADPKD. In patients with PKD1 or PKD2 mutations, the prevalence of polycystic liver disease, defined as more than 20 liver cysts, was significantly higher (71.9% vs 33.3%, P = .006), total kidney volume was significantly increased (median, 1580.7 mL vs 791.0 mL, P = .027) and mean arterial pressure was significantly higher (median, 98 mm Hg vs 91 mm Hg, P = .012). The genetic screening approach and clinical features described here are potentially beneficial for optimal management of adult sporadic polycystic kidney disease patients.

Performance of an Artificial Multi-observer Deep Neural Network for Fully Automated Segmentation of Polycystic Kidneys

Deep learning techniques are being rapidly applied to medical imaging tasks—from organ and lesion segmentation to tissue and tumor classification. These techniques are becoming the leading algorithmic approaches to solve inherently difficult image processing tasks. Currently, the most critical requirement for successful implementation lies in the need for relatively large datasets that can be used for training the deep learning networks. Based on our initial studies of MR imaging examinations of the kidneys of patients affected by polycystic kidney disease (PKD), we have generated a unique database of imaging data and corresponding reference standard segmentations of polycystic kidneys. In the study of PKD, segmentation of the kidneys is needed in order to measure total kidney volume (TKV). Automated methods to segment the kidneys and measure TKV are needed to increase measurement throughput and alleviate the inherent variability of human-derived measurements. We hypothesize that deep learning techniques can be leveraged to perform fast, accurate, reproducible, and fully automated segmentation of polycystic kidneys. Here, we describe a fully automated approach for segmenting PKD kidneys within MR images that simulates a multi-observer approach in order to create an accurate and robust method for the task of segmentation and computation of TKV for PKD patients. A total of 2000 cases were used for training and validation, and 400 cases were used for testing. The multi-observer ensemble method had mean ± SD percent volume difference of 0.68 ± 2.2% compared with the reference standard segmentations. The complete framework performs fully automated segmentation at a level comparable with interobserver variability and could be considered as a replacement for the task of segmentation of PKD kidneys by a human.

Effect of renal transcatheter arterial embolization on quality of life in patients with autosomal dominant polycystic kidney disease

Background

Currently, there are few strategies for improving the quality of life (QOL) in patients with autosomal dominant polycystic kidney disease (ADPKD) and massive kidneys. Renal transcatheter arterial embolization (TAE) reduces kidney volume, but its impact on QOL in ADPKD patients on hemodialysis is unknown. This study investigated the influence of renal TAE on QOL in ADPKD patients with massive kidneys receiving hemodialysis.

Methods

This prospective observational study enrolled 188 ADPKD patients on hemodialysis (92 men and 96 women; mean age 56.7 ± 9.1 years) who underwent renal TAE at Toranomon Hospital between August 2010 and July 2014. The 36-item Short Form Health Survey (SF-36) and our original 15-item questionnaire were used to evaluate QOL.

Results

Using a linear mixed model, the least squares mean values of the SF-36 physical component summary (PCS), mental component summary (MCS) and role/social component summary (RCS) before renal TAE were calculated as 38.21 [95% confidence interval (CI) 36.50-39.91], 48.45 (47.05-49.86) and 43.04 (40.70-45.37), respectively. These values improved to 42.0 (40.22-43.77; P < 0.001 versus before TAE), 51.25 (49.78-52.71; P = 0.001) and 49.67 (47.22-52.12; P < 0.001), respectively, 1 year after renal TAE. Scores for abdominal fullness, poor appetite and heartburn showed marked improvement after renal TAE, while scores for fever, bodily pain and sleep disorder also improved slightly, but significantly. Scores for constipation and use of analgesics/sleeping medications/laxatives did not improve significantly. All of the SF-36 scores and the scores for specific symptoms (except bodily pain, snoring and constipation) were significantly correlated with the sequential decrease of the height-adjusted total kidney volume.

Conclusions

In ADPKD patients on hemodialysis, renal TAE was effective in improving abdominal fullness, appetite, heartburn and SF-36 scores (MCS and RCS scores), but not for sleep disturbance, constipation and physical strength (PCS score).

Long-term Tolvaptan Treatment of Autosomal Dominant Polycystic Kidney Disease in Korea

A 22-year-old male patient was diagnosed with autosomal dominant polycystic kidney disease (ADPKD). He received conservative treatment with an angiotensin-converting enzyme inhibitor. Two years later, oral therapy, consisting of 60 mg tolvaptan per day, was initiated. Compared with height-adjusted total kidney volume, the rate of kidney growth reduced significantly from 7.33% to 0.66% annually, since commencement of the tolvaptan therapy. The liver enzyme profile and serum sodium level and osmolality were constantly within normal ranges. In Korea, this is the first reported case of a patient with ADPKD who received tolvaptan treatment for more than 1 year. This case demonstrates that long-term tolvaptan treatment appears to be safe, well tolerated, and effective for ADPKD.

Large Retroperitoneal Haemorrhage Following Cyst Rupture in a Patient with Autosomal Dominant Polycystic Kidney Disease

The complications of autosomal dominant polycystic kidney disease (ADPKD) include cyst rupture and haemorrhage leading to loin pain and frank haematuria. Risk factors include large kidney volume, hypertension, and renal impairment. We present a case of a young male who, following trauma to the kidney, had a life threatening bleed from his polycystic kidney. The case was initially treated with fluid resuscitation and blood transfusion but necessitated radiological embolization of bleeding source to control the blood loss. We review the risk factors and management of cyst haemorrhage in patients with ADPKD. Contact sports should be avoided as cyst rupture can lead to severe life threatening haemorrhage.

Use of targeted sequence capture and high-throughput sequencing identifies a novel PKD1 mutation involved in adult polycystic kidney disease

Polycystic kidney disease (PKD) is a common inherited disease that is characterized by a progressive development of renal cysts. Approximately 85% of PKD cases are due to mutations in the polycystin 1 (PKD1) gene. Here, we report a pedigree containing nine patients with autosomal dominant PKD (ADPKD). Using targeted exome sequencing of PKD1 and PKD2 genes, we identified a novel heterozygous frameshift mutation c.3976_3977insCT (p.F1326Sfs*21) in the PKD1 gene that segregated between affected and unaffected family members. This mutation is currently not present in the 1000 Genomes Project nor ExAC databases and is therefore a novel PKD1 mutation involved in ADPKD. These results provide a novel sequence variant for the genetic analysis of this disease.

Cux1 promotes cell proliferation and polycystic kidney disease progression in an ADPKD mouse model

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common monogenic hereditary disorders in humans characterized by fluid-filled cysts, primarily in the kidneys. Cux1, a cell cycle regulatory gene highly expressed during kidney development, is elevated in the cyst-lining cells of Pkd1 mutant mice, and in human ADPKD cells. However, forced expression of Cux1 is insufficient to induce cystic disease in transgenic mice or to induce rapid cyst formation after cilia disruption in the kidneys of adult mice. Here we report a double mutant mouse model that has a conditional deletion of the Pkd1 gene in the renal collecting ducts together with a targeted mutation in the Cux1 gene (Pkd1CD;Cux1tm2Ejn). While kidneys isolated from newborn Pkd1CD mice exhibit cortical and medullary cysts, kidneys isolated from newborn Pkd1CD;Cux1tm2Ejn-/- mice did not show any cysts. Because Cux1tm2Ejn-/- are perinatal lethal, we evaluated Pkd1CD mice that were heterozygote for the Cux1 mutation. Similar to the newborn Pkd1CD;Cux1tm2Ejn-/- mice, newborn Pkd1CD;Cux1tm2Ejn+/- mice did not show any cysts. Comparison of Pkd1CD and Pkd1CD;Cux1tm2Ejn+/- mice at later stages of development showed a reduction in the severity of PKD in the Pkd1CD;Cux1tm2Ejn+/- mice. Moreover, we observed an increase in expression of the cyclin kinase inhibitor p27, a target of Cux1 repression, in the rescued collecting ducts. Taken together, our results suggest that Cux1 expression in PKD is not directly involved in cystogenesis but promotes cell proliferation required for expansion of existing cysts, primarily by repression of p27.

Pathogenicity analysis of novel variations in Chinese Han patients with polycystic kidney disease

OBJECTIVE

Locus and allellic heterogeneity in polycystic kidney disease (PKD) is a great challenge in precision diagnosis. We aim to establish comprehensive methods to distinguish the pathogenic mutations from the variations in PKD1, PKD2 and PKHD1 genes in a limited time and lay the foundation for precisely prenatal diagnosis, preimplantation genetic diagnosis and presymptom diagnosis of PKD.

METHODS

Nested PCR combined with direct DNA sequencing were used to screen variations in PKD1, PKD2 and PKHD1 genes. The pathogenicity of de novel variations was assessed by the comprehensive methods including clinic data and literature review, databases query, analysis of co-segregation of the variants with the disease, variant frequency screening in the population, evolution conservation comparison, protein structure analysis and splice sites predictions.

RESULTS

17 novel mutations from 15 Chinese Han families were clarified including 10 mutations in PKD1 gene and 7 mutations in PKHD1 gene. The novel mutations were classified as 4 definite pathogenic, 2 highly likely pathogenic, 4 likely pathogenic, 7 indeterminate by the comprehensive analysis. The results were verified the truth by the follow-up visits.

CONCLUSIONS

The comprehensive methods may be useful in distinguishing the pathogenic mutations from the variations in PKD1, PKD2 and PKHD1 genes for prenatal diagnosis and presymptom diagnosis of PKD. Our results also enriched PKD genes mutation spectrum and evolved possible genotype-phenotype correlations of Chinese Han population.

The mutation-free embryo for in vitro fertilization selected by MALBAC-PGD resulted in a healthy live birth from a family carrying PKD 1 mutation

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD, autosomal dominant PKD or adult-onset PKD) is the most prevalent and potentially lethal kidney disease that is hereditary and lacks effective treatment. Preimplantation genetic diagnosis (PGD) of embryos in assistant reproductive technology (ART) helps to select mutation-free embryos for blocking ADPKD inheritance from the parents to their offspring. However, there are multiple pseudogenes in the PKD1 coding region, which make blocking ADPKD inheritance by PGD complicated and difficult. Therefore, this technique has not been recommended and used routinely to ADPKD family plan.

METHODS AND RESULTS

Here, we report a new strategy of performing PGD in screening (target-) mutation-free embryos. We firstly used a long-range PCR amplification and next generation sequencing to identify the potential PKD1 mutant(s). After pathogenic variants were detected, multiple annealing and looping-based amplification cycles (MALBAC), a recently developed whole genome amplification method, was used to screen embryo cells. We successfully distinguished the mutated allele among pseudogenes and obtained mutation-free embryos for implantation. The first embryo transfer attempt resulted in a healthy live birth free of ADPKD condition and chromosomal anomalies which was confirmed by aminocentesis at week 18 of gestation, and by performing live birth genetic screening.

CONCLUSIONS

The first MALBAC-PGD attempt in ADPKD patient resulted in a healthy live birth free of ADPKD and chromosomal anomalies. MALBAC-PGD also enables selecting embryos without aneuploidy together and target gene mutation, thereby increasing implantation and live birth rates.

Anticystogenic activity of a small molecule PAK4 inhibitor may be a novel treatment for autosomal dominant polycystic kidney disease

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common hereditary renal disease with no currently available targeted therapies. Based on the established connection between β-catenin signaling and renal ciliopathies, and on data from our and other laboratories showing striking similarities of this disease and cancer, we evaluated the use of an orally bioavailable small molecule, KPT-9274 (a dual inhibitor of the protein kinase PAK4 and nicotinamide phosphoribosyl transferase), for treatment of ADPKD. Treatment of PKD-derived cells with this compound not only reduces PAK4 steady-state protein levels and regulates β-catenin signaling, but also inhibits nicotinamide phosphoribosyl transferase, the rate-limiting enzyme in a key NAD salvage pathway. KPT-9274 can attenuate cellular proliferation and induce apoptosis associated with a decrease in active (phosphorylated) PAK4 and β-catenin in several Pkd1-null murine cell lines, with a less pronounced effect on the corresponding phenotypically normal cells. Additionally, KPT-9274 shows inhibition of cystogenesis in an ex vivo model of cyclic AMP-induced cystogenesis as well as in the early stage Pkd1^flox/flox:Pkhd1-Cre mouse model, the latter showing confirmation of specific anti-proliferative, apoptotic, and on-target effects. NAD biosynthetic attenuation by KPT-9274, while critical for highly proliferative cancer cells, does not appear to be important in the slower growing cystic epithelial cells during cystogenesis. KPT-9274 was not toxic in our ADPKD animal model or in other cancer models. Thus, this small molecule inhibitor could be evaluated in a clinical trial as a viable therapy of ADPKD.

High serum soluble CD200 levels in patients with autosomal dominant polycystic kidney disease

CD200 is a novel immune-effective molecule, existing in a cell membrane-bound form, as well as in a soluble form in serum, which performs to modulate inflammatory and acquired immune responses. Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of large renal cysts and progressive loss of renal function. As defects in cell cycle arrest and apoptosis of renal tubular epithelial cells occur in ADPKD, we asked whether serum soluble CD200 might underlie and effect on ADPKD. Serum soluble CD200 levels were measured in 44 patients with ADPKD and 24 healthy volunteers. Concentrations of soluble CD200 in the serum samples were quantified using an ELISA kit. The mean serum soluble CD200 levels were higher in patients with ADPKD than in the control group (71.4±29.2 and 21.4±5.6 pg/mL, p<0.001). Positive correlation was detected between serum soluble CD200 levels and glomerular filtration rate (r=0.772, p<0.001), and serum albumin level (r=0.466, p=0.001). Negative correlation was detected between serum soluble CD200 levels and serum creatinine levels (r=-0.761, p<0.001), and C reactive protein levels (r=-0.364, p=0.015). In the ADPKD patients group, serum soluble CD200 levels were lower in patients with stage 5 chronic kidney disease (CKD) than in patients with stages 1-2 (p<0.001), 3 (p=0.005) and 4 CKD (p=0.006). Serum soluble CD200 levels were similar in patients with stages 1-2, 3, and 4 CKD (p>0.05). Our results show that patients with ADPKD have activated soluble CD200 levels which were related to renal function and inflammation.

Demographics of polycystic kidney disease and captive population viability in pygmy hippopotamus (Choeropsis liberiensis)

Polycystic kidney disease (PKD) was previously diagnosed at necropsy in several pygmy hippopotami (Choeropsis liberiensis) from the Smithsonian National Zoo and Zoo Basel, suggesting a threat to the long-term viability of the captive population. We determined the incidence and demographics of PKD in the captive population historically; we tested if the condition is linked to pedigree; we investigated mode of inheritance; we examined effects of PKD on longevity; we conducted survival analysis; and we examined long-term population viability. Thirty-seven percent of 149 necropsied adult pygmy hippos were affected by PKD, and it was more common in females, controlling for the overall female-biased sex-ratio. Prevalence increased significantly with age, but most hippos were beyond their reproductive prime before developing clinical signs; thus fecundity was likely unaffected. PKD was linked to pedigree and may exhibit X-linked dominance, but further research is needed to definitively establish the mode of inheritance. PKD did not affect longevity, overall or within any age class. There was no significant correlation between inbreeding coefficient (F) and PKD, and the prevalence in wild-caught and captive-born animals was similar. Longevity for both captive-born and inbred hippos (F > 0) was significantly shorter than longevity for their wild-caught and non-inbred counterparts. Demographic projections indicated the extant population will likely experience a slow increase over time, provided there are no space constraints. We conclude that although PKD is an important cause of morbidity and mortality in pygmy hippos, the condition is not a primary concern for overall viability of the captive population.

Surgical Outcome of Cerebral Aneurysm Clipping Treated with Immunosuppressants: Report of 11 Cases and Review of the Literature

There are no reports on the outcomes of clippings in patients who receive immunosuppressants, for example, due to connective tissue diseases or following organ transplantation. We thoroughly reviewed these cases focusing on the perioperative management phase. The study included 11 patients with intracranial aneurysms who were taking immunosuppressants; between 2007 and 2014. We performed 12 clipping surgeries. Their clinical records were reviewed for age and gender, aneurysms' location and size, perioperative management of the immunosuppressive drugs, and surgical complications. The study included nine females and two males, aged between 52 and 71 years (mean 60.1 ± 8.5 years). The clinical presentation in five cases was subarachnoid hemorrhage (SAH); the aneurysm was incidentally diagnosed in six patients (7 aneurysms). The reasons for taking immunosuppressants were autoimmune disorder in nine patients and liver transplantation in two patients. Daily intake of oral immunosuppressants for the patients with liver transplantation was discontinued for 2-4 days, and no infectious complications were evidenced. The weekly course of immunosuppressive drugs for the patients with autoimmune disorder was continued in eight of nine patients. Caution must be exercised when considering the suitability of clipping for patients taking immunosuppressants, but surgery outcomes are generally favorable; when operative treatment is required, we believe it to be comparatively safe, if the perioperative management is conducted in close collaboration with the relevant departments.

Is Autosomal Dominant Polycystic Kidney Disease Becoming a Pediatric Disorder?

Autosomal dominant polycystic kidney disease (ADPKD) affects 1 in 400 to 1,000 live births, making it the most common monogenic cause of renal failure. Although no definite cure is available yet, it is important to affect disease progression by influencing modifiable factors such as hypertension and proteinuria. Besides this symptomatic management, the only drug currently recommended in Europe for selected adult patients with rapid disease progression, is the vasopressin receptor antagonist tolvaptan. However, the question remains whether these preventive interventions should be initiated before extensive renal damage has occurred. As renal cyst formation and expansion begins early in life, frequently in utero, ADPKD should no longer be considered an adult-onset disease. Moreover, the presence of hypertension and proteinuria in affected children has been reported to correlate well with disease severity. Until now, it is controversial whether children at-risk for ADPKD should be tested for the presence of the disease, and if so, how this should be done. Herein, we review the spectrum of pediatric ADPKD and discuss the pro and contra of testing at-risk children and the challenges and unmet needs in pediatric ADPKD care.

Gastrointestinal Manifestations of Autosomal-Dominant Polycystic Kidney Disease

Autosomal-dominant polycystic kidney disease (ADPKD) is the most commonly inherited kidney disease, and the fourth most common cause of end-stage renal disease. ADPKD is a systemic disorder, associated with numerous extrarenal manifestations, including polycystic liver disease, the most common gastrointestinal manifestation, and diverticular disease, inguinal, and ventral hernias, pancreatic cysts, and large bile duct abnormalities. All of these gastrointestinal manifestations play a significant role in disease burden in ADPKD, particularly in the later decades of life. Thus, as ADPKD becomes more recognized, it is important for gastroenterologists to be knowledgeable of this monogenic disorder's effects on the digestive system.

Toll-Like Receptors in the Progression of Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cause of chronic kidney disease. The intriguing role of innate immune system and inflammation become a target for potential therapeutic approach to slow progression. When toll-like receptors (TLRs) signaling and their receptors activate, they start a cascade of intracellular signaling that induces the production of the inflammatory cytokines and chemokines. Thus, we aim to investigate the association of TLRs between progression of ADPKD. Ninety ADPKD patients and ninety matched controls were enrolled this prospective study and were followed during 3 years. TLR-2 and TLR-4 gene polymorphisms and expressions were measured. Hypertension was diagnosed with ambulatory blood pressure monitoring. Rapid progression was defined as sustained decline in estimated glomerular filtration rate (eGFR) of more than 5 mL/min per 1.73 m² per year. TLR-4Asp299Gly polymorphisms were significantly different between patient and control group (P < 0.05). Also, TLR-2 and TLR-4 gene expressions were significantly different between the ADPKD patients and the control subjects (P < 0.05). The expression levels of both TLR-2 and TLR-4 were found to be higher in the rapid progression groups comparing the slow progression group (P < 0.05). TLR-2 gene expression, hypertension and uric acid were found to be independent risk factors in identifying rapid progression in ADPKD patients. TLR-2 and TLR-4 gene expressions are associated with rapid progression in ADPKD patients. TLRs may play a role in the progression of ADPKD.

Tolvaptan and Kidney Pain in Patients With Autosomal Dominant Polycystic Kidney Disease: Secondary Analysis From a Randomized Controlled Trial

Background

Kidney pain is a common complication in patients with autosomal dominant polycystic kidney disease (ADPKD), and data from the TEMPO 3:4 trial suggested that tolvaptan, a vasopressin V2 receptor antagonist, may have a positive effect on kidney pain in this patient group. Because pain is difficult to measure, the incidence of kidney pain leading to objective medical interventions was used in the present study to assess pain.

Study Design

Secondary analysis from a randomized controlled trial.

Setting & Participants

Patients with ADPKD with preserved kidney function.

Intervention

Tolvaptan or placebo.

Outcomes

Kidney pain events defined by objective medical interventions.

Measurements

Kidney pain events were recorded and independently adjudicated. Incidence of a first kidney pain event was assessed overall and categorized into 5 subgroups according to severity.

Results

Of 1,445 participating patients (48.4% women; mean age, 39 ± 7 [SD] years; mean estimated glomerular filtration rate, 81 ± 22 mL/min/1.73 m²; median total kidney volume, 1,692 [IQR, 750–7,555] mL), 50.9% reported a history of kidney pain at baseline. History of urinary tract infections, kidney stones, or hematuria (all P < 0.001) and female sex (P < 0.001) were significantly associated with history of kidney pain. Tolvaptan use resulted in a significantly lower incidence of kidney pain events when compared to placebo: 10.1% versus 16.8% (P < 0.001), with a risk reduction of 36% (HR, 0.64; 95% CI, 0.48–0.86). The reduction in pain event incidence by tolvaptan was found in all groups irrespective of pain severity and was independent of predisposing factors (P for interaction > 0.05). The effect of tolvaptan was explained at least in part by a decrease in incidence of urinary tract infections, kidney stones, and hematuria when compared to placebo.

Limitations

Trial has specific inclusion criteria for total kidney volume and kidney function.

Conclusions

Tolvaptan decreased the incidence of kidney pain events independent of patient characteristics predisposing for kidney pain and possibly in part due to reductions in ADPKD-related complications.

Technical Evaluation: Identification of Pathogenic Mutations in PKD1 and PKD2 in Patients with Autosomal Dominant Polycystic Kidney Disease by Next-Generation Sequencing and Use of a Comprehensive New Classification System

Genetic testing of PKD1 and PKD2 is expected to play an increasingly important role in determining allelic influences in autosomal dominant polycystic kidney disease (ADPKD) in the near future. However, to date, genetic testing is not commonly employed because it is expensive, complicated because of genetic heterogeneity, and does not easily identify pathogenic variants. In this study, we developed a genetic testing system based on next-generation sequencing (NGS), long-range polymerase chain reaction, and a new software package. The new software package integrated seven databases and provided access to five cloud-based computing systems. The database integrated 241 polymorphic nonpathogenic variants detected in 140 healthy Japanese volunteers aged >35 years, who were confirmed by ultrasonography as having no cysts in either kidney. Using this system, we identified 60 novel and 30 known pathogenic mutations in 101 Japanese patients with ADPKD, with an overall detection rate of 89.1% (90/101) [95% confidence interval (CI), 83.0%-95.2%]. The sensitivity of the system increased to 93.1% (94/101) (95% CI, 88.1%-98.0%) when combined with multiplex ligation-dependent probe amplification analysis, making it sufficient for use in a clinical setting. In 82 (87.2%) of the patients, pathogenic mutations were detected in PKD1 (95% CI, 79.0%-92.5%), whereas in 12 (12.8%) patients pathogenic mutations were detected in PKD2 (95% CI, 7.5%-21.0%); this is consistent with previously reported findings. In addition, we were able to reconfirm our pathogenic mutation identification results using Sanger sequencing. In conclusion, we developed a high-sensitivity NGS-based system and successfully employed it to identify pathogenic mutations in PKD1 and PKD2 in Japanese patients with ADPKD.

Clinical Manifestation and Management of ADPKD in Western Countries

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease in Western countries. The prevalence is between 2.4/10,000 and 3.9/10,000. ADPKD represents a systemic disease resulting in deterioration in renal function. Until now, mutations in two genes (PKD1 and PKD2) have been identified. Recently, the European Medicines Agency (EMA) approved the use of the vasopressin V2 receptor antagonist tolvaptan to slow the progression of cyst development and renal insufficiency connected with ADPKD in adult patients with chronic kidney disease stages 1-3 at initiation of treatment with evidence of rapidly progressing disease. Whereas the EMA approved the release of tolvaptan, the US Food and Drug Administration (FDA) requested further data on side effects and the selection of patient cohorts who may benefit from treatment.

SUMMARY

This review focused on advances in the management and treatment of ADPKD in Western countries.

KEY MESSAGE

ADPKD represents the fourth most common cause of end-stage renal disease (ESRD) in Western countries. ADPKD is a multisystemic disease characterized by the progressive development of bilateral renal cysts, resulting in enlargement of the kidney volume due to cystic formations, hypertension, hematuria, and loss of renal function. ADPKD is associated with high inter- and intrafamilial variability in disease appearance and progression. Patients with PKD1 mutations typically have a more severe phenotype than those with PKD2 mutations. ADPKD is under intensive investigation. Vasopressin and the associated cyclic adenosine monophosphate-related signaling pathways have been demonstrated to be important contributors to cyst growth in ADPKD. Supportive treatments are recommended with the aim of reducing morbidity and mortality associated with disease manifestations. In the past years, several agents have been investigated in ADPKD patients, including mTOR inhibitors, somatostatin analogs, statins, and vasopressin V2 receptor antagonists.

FACTS FROM EAST AND WEST

(1) ADPKD is diagnosed globally by ultrasound detection of kidney enlargement and presence of cysts. Recent analyses of variants of the PKD1 and PKD2 genes by next-generation sequencing in Chinese and Western ADPKD patients might lead to the development of reliable genetic tests. (2) Besides lifestyle changes (low-salt diet, sufficient fluid intake, and no smoking), blood pressure control is the primary nonspecific treatment recommended by Kidney Disease - Improving Global Outcomes (KDIGO) for ADPKD patients. How low the blood pressure target should be and what the means of achieving it are remain open questions depending on the severity of chronic kidney disease and the age of the patients. In a recent Chinese study, diagnostic needle aspiration and laparoscopic unroofing surgery successfully improved infection, pain, and hypertension. Peritoneal dialysis was found to be a feasible treatment for most Chinese ADPKD patients with ESRD. In most Western centers, patients without contraindication are selected for peritoneal dialysis. Kidney transplantation with concurrent bilateral nephrectomy was successful in relieving hypertension and infection in Chinese ADPKD patients. In Western countries, sequential surgical intervention with kidney transplantation after nephrectomy, or the other way round, is preferred in order to reduce risks. (3) The vasopressin 2 receptor antagonist tolvaptan was approved in Europe, Canada, Japan, and Korea to slow down progression of kidney disease in ADPKD patients. Tolvaptan is not yet approved in the USA or in China. mTOR pathway-targeting drugs are currently under evaluation: mTOR inhibitors could slow down the increase in total kidney volume in a cohort of Western and Japanese ADPKD patients. Western studies as well as an ongoing study in China failed to show benefit from rapamycin. A study performed in Italy indicates protective effects of the somatostatin analog octreotide in ADPKD patients. Western and Chinese studies revealed a potential beneficial effect of triptolide, the active substance of the traditional Chinese medicine Tripterygium wilfordii (Lei Gong Teng) to prevent worsening in ADPKD patients.

Autosomal Dominant Polycystic Disease is Associated with Depressed Levels of Soluble Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by multiple, large renal cysts and impaired kidney function. Although the reason for the development of kidney cysts is unknown, ADPKD is associated with cell cycle arrest and abundant apoptosis of renal tubular epithelial cells.

AIMS

We asked whether serum-soluble TNF-related apoptosis-inducing ligand (sTRAIL) might underlie ADPKD.

STUDY DESIGN

Case-control study.

METHODS

Serum sTRAIL levels were measured in 44 patients with ADPKD and 18 healthy volunteers. The human soluble TRAIL/Apo2L ELISA kit was used for the in vitro quantitative determination of sTRAIL in serum samples.

RESULTS

Mean serum sTRAIL levels were lower in patients with ADPKD as compared to the control group (446.9±103.1 and 875.9±349.6 pg/mL, p<0.001). Serum sTRAIL levels did not differ among stages of renal failure in patients with ADPKD. There was no correlation between serum sTRAIL levels and estimated glomerular filtration rate in patients with ADPKD (p>0.05).

CONCLUSION

Our results show that ADPKD patients have depressed sTRAIL levels, indicating apoptosis unrelated to the stage of chronic renal failure.

Pain in the Geriatric Patient with Advanced Chronic Disease

The World Health Organization, one of the leading authorities on pain management, stressed the need for further guidelines to help manage pain in patients with chronic disease. In light of the impact of pain on morbidity and quality of life, this article summarizes current knowledge about pain experienced by older adults in 3 advanced non-cancer-related chronic diseases (ie, congestive heart failure, end-stage renal disease, and stroke) in which pain is common but not typically a primary focus of disease management. This article examines the data on the prevalence of pain, co-occurring symptoms, and challenges in managing pain in these conditions.

Combined liver-kidney transplantation for polycystic liver and kidney disease: analysis from the United Network for Organ Sharing dataset

BACKGROUND & AIMS

The purpose of this study was to evaluate predictors of outcomes in combined liver-kidney transplants for polycystic liver and kidney disease.

METHODS

We queried the United Network for Organ Sharing dataset for combined liver-kidney transplants performed from 1988 to 2013.

RESULTS

Out of 107 patients who had combined liver-kidney transplants for polycystic liver and kidney disease, 84 were women (78.5%) with a mean age of 54.9 ±7.2 years. Kaplan-Meier analysis demonstrated that patients undergoing liver-kidney transplantation for polycystic liver and kidney disease had better survival than patients with polycystic liver disease undergoing liver transplant alone and those undergoing liver-kidney transplantation for other indications. This group had a 1-, 3- and 5-year survival of 91%, 90% and 90%, respectively. Multivariable analysis demonstrated that an indication of polycystic liver and kidney disease for combined liver-kidney transplant (hazard ratio, 0.29; 95% confidence interval, 0.129-0.526; P < 0.001) and Model for End-Stage Liver Disease score (hazard ratio, 1.271; 95% confidence interval, 1.093-1.477; P = 0.002) are independently associated with patient survival. In a propensity score analysis adjusting for age, gender, cold ischaemia time and total bilirubin and excluding hepatitis C, we found that patients transplanted with combined liver-kidney for other indications have similar survival compared with our study group.

CONCLUSIONS

Combined liver-kidney transplantation for polycystic liver and kidney disease can achieve good outcomes in selected patients. On Cox regression analysis, patients with polycystic liver and kidney disease undergoing liver-kidney transplantation had better survival compared with patients with combined liver-kidney for other indications. After excluding hepatitis C patients, those transplanted for polycystic liver and kidney disease vs other indications had similar survival after combined liver-kidney transplantation. Interestingly, patients in the combined polycystic liver and kidney disease group have significantly better outcomes than patients with polycystic liver disease undergoing liver transplant alone.

Effect of Sirolimus on Disease Progression in Patients with Autosomal Dominant Polycystic Kidney Disease and CKD Stages 3b-4

BACKGROUND AND OBJECTIVES

The effect of mammalian target of rapamycin (mTOR) inhibitors has never been tested in patients with autosomal dominant polycystic kidney disease (ADPKD) and severe renal insufficiency.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this academic, prospective, randomized, open label, blinded end point, parallel group trial (ClinicalTrials.gov no. NCT01223755), 41 adults with ADPKD, CKD stage 3b or 4, and proteinuria ≤0.5 g/24 h were randomized between September of 2010 and March of 2012 to sirolimus (3 mg/d; serum target levels of 5-10 ng/ml) added on to conventional therapy (n=21) or conventional treatment alone (n=20). Primary outcome was GFR (iohexol plasma clearance) change at 1 and 3 years versus baseline.

RESULTS

At the 1-year preplanned interim analysis, GFR fell from 26.7±5.8 to 21.3±6.3 ml/min per 1.73 m(2) (P<0.001) and from 29.6±5.6 to 24.9±6.2 ml/min per 1.73 m(2) (P<0.001) in the sirolimus and conventional treatment groups, respectively. Albuminuria (73.8±81.8 versus 154.9±152.9 μg/min; P=0.02) and proteinuria (0.3±0.2 versus 06±0.4 g/24 h; P<0.01) increased with sirolimus. Seven patients on sirolimus versus one control had de novo proteinuria (P=0.04), ten versus three patients doubled proteinuria (P=0.02), 18 versus 11 patients had peripheral edema (P=0.04), and 14 versus six patients had upper respiratory tract infections (P=0.03). Three patients on sirolimus had angioedema, 14 patients had aphthous stomatitis, and seven patients had acne (P<0.01 for both versus controls). Two patients progressed to ESRD, and two patients withdrew because of worsening of proteinuria. These events were not observed in controls. Thus, the independent data and safety monitoring board recommend early trial termination for safety reasons. At 1 year, total kidney volume (assessed by contrast-enhanced computed tomography imaging) increased by 9.0% from 2857.7±1447.3 to 3094.6±1519.5 ml on sirolimus and 4.3% from 3123.4±1695.3 to 3222.6±1651.4 ml on conventional therapy (P=0.12). On follow-up, 37% and 7% of serum sirolimus levels fell below or exceeded the therapeutic range, respectively.

CONCLUSIONS

Finding that sirolimus was unsafe and ineffective in patients with ADPKD and renal insufficiency suggests that mTOR inhibitor therapy may be contraindicated in this context.

Pre-transplant treatment of large polycystic kidney

AIM: To evaluate the indications, optimal timing and outcomes of native nephrectomy and other techniques in pretransplant treatment of autosomal dominant polycystic kidney disease (PKD).

METHODS: A literature review was conducted using the PubMed and Epistemonikos databases. Keywords for pre-transplant surgical management of polycystic kidneys were: Transplant, treatment and PKD. Keywords for pre-treatment embolization of PKD were: Embolization, transplant and polycystic kidney disease. The inclusion criterions were all articles found using this search method. The exclusion criterions were articles found to include bias and not attending pre-transplant treatment options. Fifteen articles were included in our final analysis. Ten articles were found regarding embolization of PKD of which three reviews were selected for final analysis. The reviews were divided into pre transplant and intra transplant treatment for the surgical treatment of PKD. All articles meeting inclusion criteria were thoroughly analyzed by two independent reviewers. A third independent reviewer was consulted if the reviewers did not agree upon the inclusion or exclusion of a specific article. No statistical analysis was performed.

RESULTS: Studies vary regarding the technique used (open or laparoscopic), laterality (single or bilateral) and temporality of nephrectomy with respect to renal transplant (pre-transplant or simultaneous to transplant). Several groups argue in favor of simultaneous nephrectomy and kidney transplant since it avoids the deleterious effects of being anefric. Long-term results and patient satisfaction are acceptable. However, it is associated with increased operative time, transfusion rate, morbidity and length of hospital stay. Based on small sample studies, bilateral nephrectomy prior to transplant has been associated with a higher risk of morbidity and mortality. Studies on laparoscopic approach report it as a feasible and safe alternative to the open surgery approach, highlighting its lower complication rate, transfusions and shorter hospital stay. Arterial embolization of the kidney appears as an effective and low morbid alternative for the management of large native kidneys. The reduction in renal size allow transplant in a significant number of patients, which makes it an appealing alternative to surgery.

CONCLUSION: There is limited evidence regarding best pretrasnplant treatment of large PKD but to date embolization seems an appealing alternative to augment space for renal graft allocation.

Effect of genotype on the severity and volume progression of polycystic liver disease in autosomal dominant polycystic kidney disease

BACKGROUND

The autosomal dominant polycystic kidney disease (APDKD) genotype influences renal phenotype severity but its effect on polycystic liver disease (PLD) is unknown. Here we analyzed the influence of genotype on liver phenotype severity.

METHODS

Clinical data were retrieved from electronic records of patients who were mutation screened with the available liver imaging (n = 434). Liver volumes were measured by stereology (axial or coronal images) and adjusted to height (HtLV).

RESULTS

Among the patients included, 221 (50.9%) had truncating PKD1 (PKD1-T), 141 (32.5%) nontruncating PKD1 (PKD1-NT) and 72 (16.6%) PKD2 mutations. Compared with PKD1-NT and PKD2, patients with PKD1-T had greater height-adjusted total kidney volumes (799 versus 610 and 549 mL/m; P < 0.001). HtLV was not different (1042, 1095 and 1058 mL/m; P = 0.64) between the three groups, but females had greater HtLVs compared with males (1114 versus 1015 mL/m; P < 0.001). Annualized median liver growth rates were 1.68, 1.5 and 1.24% for PKD1-T, PKD1-NT and PKD2 mutations, respectively (P = 0.49), and remained unaffected by the ADPKD genotype when adjusted for age, gender and baseline HtLV. Females <48 years of age had higher annualized growth rates compared with those who were older (2.65 versus 0.09%; P < 0.001). After age 48 years, 58% of females with severe PLD had regression of HtLV, while HtLV continued to increase in males.

CONCLUSIONS

In contrast to the renal phenotype, the ADPKD genotype was not associated with the severity or growth rate of PLD in ADKPD patients. This finding, along with gender influence, indicates that modifiers beyond the disease gene significantly influence the liver phenotype.

Conformational dynamics of Ca2+-dependent responses in the polycystin-2 C-terminal tail

The C-terminal tail of polycystin-2 is crucial for channel regulation and contains a Ca2+-binding EF-hand domain and a coiled-coil domain. The C-terminal tail and isolated EF-hand share similar Ca2+-binding affinities; however, their dynamic responses to Ca2+ are different.

Automated Segmentation of Kidneys from MR Images in Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND OBJECTIVES

Our study developed a fully automated method for segmentation and volumetric measurements of kidneys from magnetic resonance images in patients with autosomal dominant polycystic kidney disease and assessed the performance of the automated method with the reference manual segmentation method.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Study patients were selected from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease. At the enrollment of the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease Study in 2000, patients with autosomal dominant polycystic kidney disease were between 15 and 46 years of age with relatively preserved GFRs. Our fully automated segmentation method was on the basis of a spatial prior probability map of the location of kidneys in abdominal magnetic resonance images and regional mapping with total variation regularization and propagated shape constraints that were formulated into a level set framework. T2-weighted magnetic resonance image sets of 120 kidneys were selected from 60 patients with autosomal dominant polycystic kidney disease and divided into the training and test datasets. The performance of the automated method in reference to the manual method was assessed by means of two metrics: Dice similarity coefficient and intraclass correlation coefficient of segmented kidney volume. The training and test sets were swapped for crossvalidation and reanalyzed.

RESULTS

Successful segmentation of kidneys was performed with the automated method in all test patients. The segmented kidney volumes ranged from 177.2 to 2634 ml (mean, 885.4±569.7 ml). The mean Dice similarity coefficient ±SD between the automated and manual methods was 0.88±0.08. The mean correlation coefficient between the two segmentation methods for the segmented volume measurements was 0.97 (P<0.001 for each crossvalidation set). The results from the crossvalidation sets were highly comparable.

CONCLUSIONS

We have developed a fully automated method for segmentation of kidneys from abdominal magnetic resonance images in patients with autosomal dominant polycystic kidney disease with varying kidney volumes. The performance of the automated method was in good agreement with that of manual method.

Long-term functional results of aspiration and sclerotherapy with ethanol in patients with autosomal dominant polycystic kidney disease: a non-randomized pilot clinical study

PURPOSE

To evaluate the long-term effect of aspiration and sclerotherapy treatment on the pain control, blood pressure regulation, and quality of life (QoL) in patients with autosomal dominant polycystic disease (ADPKD).

METHODS

Twenty-five ADPKD patients with a total of 32 dominant cysts were treated with ultrasound guidance percutaneous aspiration and 96% ethanol injection, between 2002 and 2014. Twenty-one dominant cysts of 16 patients who had a minimum of 10-year follow-up were included in this study. The level of pain [visual analog score (VAS)], narcotic usage, blood pressure and serum creatinine level, QoL questionnaire, and radiological dominant cyst size was evaluated before and after procedure, retrospectively.

RESULTS

The mean dominant cyst size was even smaller after follow-up of 10 years. Mean dominant cyst size was 7.2 ± 2.3 cm before the procedure and 0.9 ± 0.9 and 3.3 ± 1.2 cm after the one- and 10-year follow-ups, respectively (p < 0.05). VAS and QoL scores were improved after 10 years of follow-up. There was no relation between cyst size and VAS score as well as QoL questionnaire score. End-stage renal disease occurred in 50%, and there was no significant improvement in blood pressure of these patients.

CONCLUSIONS

Aspiration and sclerotherapy with ethanol is a minimal-invasive, safe, and inexpensive outpatient treatment method with acceptable short- and long-term results in ADPKD patients. Aspiration and sclerotherapy with ethanol can be an option for patients with ADPKD.

CT and MR imaging for evaluation of cystic renal lesions and diseases

Cystic renal lesions are commonly encountered in abdominal imaging. Although most cystic renal lesions are benign simple cysts, complex renal cysts, infectious cystic renal disease, and multifocal cystic renal disease are also common phenomena. The Bosniak classification system provides a useful means of categorizing cystic renal lesions but places less emphasis on their underlying pathophysiology. Cystic renal diseases can be categorized as focal, multifocal, or infectious lesions. Diseases that manifest with focal lesions, such as cystic renal cell carcinoma, mixed epithelial and stromal tumor, and cystic nephroma, are often difficult to differentiate but have differing implications for follow-up after resection. Multifocal cystic renal lesions can be categorized as acquired or heritable. Acquired entities, such as glomerulocystic kidney disease, lithium-induced nephrotoxicity, acquired cystic kidney disease, multicystic dysplastic kidney, and localized cystic renal disease, often have distinct imaging and clinical features that allow definitive diagnosis. Heritable diseases, such as autosomal dominant polycystic kidney disease, von Hippel-Lindau disease, and tuberous sclerosis, are usually easily identified and have various implications for patient management. Infectious diseases have varied imaging appearances, and the possibility of infection must not be overlooked when assessing a cystic renal lesion. A thorough understanding of the spectrum of cystic renal disease will allow the radiologist to make a more specific diagnosis and provide the clinician with optimal recommendations for further diagnostic testing and follow-up imaging.

Suitability of Patients with Autosomal Dominant Polycystic Kidney Disease for Renal Transcatheter Arterial Embolization

In patients with autosomal dominant polycystic kidney disease (ADPKD), massive renal enlargement is a serious problem. Renal transcatheter arterial embolization (TAE) can reduce renal volume (RV), but effectiveness varies widely, and the reasons remain unclear. We investigated factors affecting renal volume reduction rate (RVRR) after renal TAE in all 449 patients with ADPKD who received renal TAE at Toranomon Hospital from January of 2006 to July of 2013, including 228 men and 221 women (mean age =57.0±9.1 years old). One year after renal TAE, the RVRR ranged from 3.9% to 84.8%, and the least squares mean RVRR calculated using a linear mixed model was 45.5% (95% confidence interval [95% CI], 44.2% to 46.8%). Multivariate analysis using the linear mixed model revealed that RVRR was affected by the presence of large cysts with wall thickening (regression coefficient [RC], -6.10; 95% CI, -9.04 to -3.16; P<0.001), age (RC, -0.82; 95% CI, -1.03 to -0.60; P<0.001), dialysis duration (RC, -0.10; 95% CI, -0.18 to -0.03; P<0.01), systolic BP (RC, 0.39; 95% CI, 0.19 to 0.59; P<0.001), and the number of microcoils used for renal TAE (RC, 1.35; 95% CI, 0.83 to 1.86; P<0.001). Significantly more microcoils were needed to achieve renal TAE in patients with younger age and shorter dialysis duration. In conclusion, cyst wall thickening had an important effect on cyst volume reduction. Renal TAE was more effective in patients who were younger, had shorter dialysis duration, or had hypertension, parameters that might associate with cyst wall stiffness and renal artery blood flow.

Native Nephrectomy in Renal Transplant Recipients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Native nephrectomy (NNx) is often done in patients with autosomal dominant polycystic kidney disease (ADPKD). Controversy exists concerning the need and timing of nephrectomy in transplant candidates. We hypothesize that post-transplant NNx does not negatively impact patient and graft survival.

METHODS

Among 470 ADPKD transplant recipients included in the study, 114 (24.3%) underwent pre- (30.7%) or post-transplant (69.3%) NNx. Clinical data was retrieved from electronic records. Follow up was until death, graft loss or June 2014. Perioperative complications were compared between the surgical techniques (open or laparoscopic) and between the pre- and post-transplant nephrectomy groups. The effect of nephrectomy on graft survival was analyzed as a time-dependent covariate when performed post-transplant.

RESULTS

Mean age at transplant was 52.4 years, 53.8% were male, 93% white, 70% were from living donors and 56.8% were pre-emptive. Nephrectomy was done laparoscopically in 31% and 86% in the pre- and post- transplant nephrectomy groups, respectively. Complications were less common in those who underwent nephrectomy post-transplant (26.6% vs. 48%, p=0.03) but were similar regardless of surgical technique (open, 33.3% vs. laparoscopic 33%, p=0.66). Patient and graft survival were similar between those who underwent pre-transplant nephrectomy and the rest of the recipients. In the post-transplant nephrectomy group, nephrectomy did not affect patient (HR 0.77, CI 0.38-1.54, p=0.45) or graft survival (HR 1.0, CI 0.57-1.76, p=0.1).

CONCLUSIONS

Nephrectomy does not adversely affect patient or graft survival. Post-transplant nephrectomy is feasible when indicated without compromising long term graft outcome and has fewer complications than pre-transplant nephrectomy.

Automatic total kidney volume measurement on follow-up magnetic resonance images to facilitate monitoring of autosomal dominant polycystic kidney disease progression

BACKGROUND

Renal imaging examinations provide high-resolution information about the anatomic structure of the kidneys and are used to measure total kidney volume (TKV) in autosomal dominant polycystic kidney disease (ADPKD) patients. TKV has become the gold-standard image biomarker for ADPKD progression at early stages of the disease and is used in clinical trials to characterize treatment efficacy. Automated methods to segment the kidneys and measure TKV are desirable because of the long time requirement for manual approaches such as stereology or planimetry tracings. However, ADPKD kidney segmentation is complicated by a number of factors, including irregular kidney shapes and variable tissue signal at the kidney borders.

METHODS

We describe an image processing approach that overcomes these problems by using a baseline segmentation initialization to provide automatic segmentation of follow-up scans obtained years apart. We validated our approach using 20 patients with complete baseline and follow-up T1-weighted magnetic resonance images. Both manual tracing and stereology were used to calculate TKV, with two observers performing manual tracings and one observer performing repeat tracings. Linear correlation and Bland-Altman analysis were performed to compare the different approaches.

RESULTS

Our automated approach measured TKV at a level of accuracy (mean difference ± standard error = 0.99 ± 0.79%) on par with both intraobserver (0.77 ± 0.46%) and interobserver variability (1.34 ± 0.70%) of manual tracings. All approaches had excellent agreement and compared favorably with ground-truth manual tracing with interobserver, stereological and automated approaches having 95% confidence intervals ∼ ± 100 mL.

CONCLUSIONS

Our method enables fast, cost-effective and reproducible quantification of ADPKD progression that will facilitate and lower the costs of clinical trials in ADPKD and other disorders requiring accurate, longitudinal kidney quantification. In addition, it will hasten the routine use of TKV as a prognostic biomarker in ADPKD.

MicroRNAs in the Cholangiopathies: Pathogenesis, Diagnosis, and Treatment

The cholangiopathies are a group of liver diseases resulting from different etiologies but with the cholangiocyte as the primary target. As a group, the cholangiopathies result in significant morbidity and mortality and represent one of the main indications for liver transplant in both children and adults. Contributing to this situation is the absence of a thorough understanding of their pathogenesis and a lack of adequate diagnostic and prognostic biomarkers. MicroRNAs are small non-coding RNAs that modify gene expression post-transcriptionally. They have been implicated in the pathogenesis of many diseases, including the cholangiopathies. Thus, in this review we provide an overview of the literature on miRNAs in the cholangiopathies and discuss future research directions.

Genetic and Informatic Analyses Implicate Kif12 as a Candidate Gene within the Mpkd2 Locus That Modulates Renal Cystic Disease Severity in the Cys1cpk Mouse

We have previously mapped the interval on Chromosome 4 for a major polycystic kidney disease modifier (Mpkd) of the B6(Cg)-Cys1^cpk/J mouse model of recessive polycystic kidney disease (PKD). Informatic analyses predicted that this interval contains at least three individual renal cystic disease severity-modulating loci (Mpkd1-3). In the current study, we provide further validation of these predicted effects using a congenic mouse line carrying the entire CAST/EiJ (CAST)-derived Mpkd1-3 interval on the C57BL/6J background. We have also generated a derivative congenic line with a refined CAST-derived Mpkd1-2 interval and demonstrated its dominantly-acting disease-modulating effects (e.g., 4.2-fold increase in total cyst area; p<0.001). The relative strength of these effects allowed the use of recombinants from these crosses to fine map the Mpkd2 effects to a <14 Mbp interval that contains 92 RefSeq sequences. One of them corresponds to the previously described positional Mpkd2 candidate gene, Kif12. Among the positional Mpkd2 candidates, only expression of Kif12 correlates strongly with the expression pattern of Cys1 across multiple anatomical nephron structures and developmental time points. Also, we demonstrate that Kif12 encodes a primary cilium-associated protein. Together, these data provide genetic and informatic validation of the predicted renal cystic disease-modulating effects of Mpkd1-3 loci and implicate Kif12 as the candidate locus for Mpkd2.