The diagnosis and prognosis of autosomal dominant polycystic kidney disease

Establishing Meaningful Patient-Centered Outcomes with Relevance for Patients with Polycystic Kidney Disease: Patient, Caregiver, and Researcher Priorities for Research in Polycystic Kidney Disease

Key Points

Participants are less concerned about mortality than they are about kidney health. Psychological effect emerged as the most important theme regarding the effects of polycystic kidney disease on patients.

Background

Patient involvement in research can help to ensure that the evidence generated aligns with their needs and priorities. In the Establishing Meaningful Patient-Centered Outcomes with Relevance for Patients with Polycystic Kidney Disease (PKD) project, we aimed to identify patient-important outcomes and discuss the effect of PKD on patients.

Methods

Nine focus groups were held with adult patients with PKD, caregivers, and clinical or research experts in PKD. We used a nominal, multivote technique to rank patient-important outcomes to be prioritized by future PKD research. We conducted a thematic analysis of verbatim transcriptions to identify themes regarding the effect of PKD on their daily lives. Other focus group topics included insurability and patient engagement.

Results

Ninety patients and/or caregivers and eight clinicians and/or researchers participated in the focus groups. Nine focus groups yielded 35 outcomes important to patients that were grouped into six categories, ranked in order of importance: kidney health, comorbidities, lifestyle, psychological effect, family and awareness, and mortality. Regarding the effect of PKD on the patient's daily lives, we identified five themes, listed in order of importance: psychological effect, effect on daily living, issues affecting decision making, health care-related issues, and PKD-specific testing dilemmas.

Conclusions

This study of stakeholder engagement in patients with PKD revealed important priorities and values that should be considered for future research and when caring for patients with PKD. Future research should focus on kidney health and managing comorbidities in patients with PKD. This will help to bridge the knowledge gap and develop meaningful comparative effectiveness research in PKD.

Targeting TRPM3 as a potential therapeutic approach for autosomal dominant polycystic kidney disease

Cystic diseases, especially autosomal dominant polycystic kidney disease (ADPKD; incidence approx. 1/1000), are a leading cause of renal failure, caused by appearance and growth of renal cysts that can lead to renal failure in middle age. Most ADPKD cases are caused by mutations in PKD1 or PKD2, encoding polycystin-1 (PC1) and polycystin-2 (PC2). PC1 is a mechanosensor that controls PC2, a Ca2+-permeable cation channel that, by regulating cytoplasmic Ca2+, prevents adenylyl cyclase producing cyst-promoting concentrations of cAMP. In other systems, there is evidence that PC2 interacts with TRPM3. We therefore examined the effect of pharmacological activators and inhibitors of TRPM3 on cyst formation in cultured mouse kidney rudiments exposed to a range of concentrations of forskolin, a cAMP-elevating drug commonly used experimentally to induce cysts in cultured kidneys. We found that TRPM3 inhibitors (isosakuranetin, primidone, diclofenac) increased cyst formation, while TRPM3 activators (CIM0216 and nifedipine) greatly reduced cyst formation and reduced the sensitivity of kidneys to forskolin. These preclinical, in-vitro data suggest that TRPM3 may be a promising target in ADPKD management.

Mitral Valve Prolapse in a Patient With Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a multisystemic heterogeneous disease characterized by the presence of cysts in several organs leading to progressive dysfunction. The cardiovascular manifestations of ADPKD include hypertension, left ventricular hypertrophy, and valvular heart disease, predominantly mitral valve abnormalities. We present the case of a 30-year-old male with a past medical history of ADPKD who was admitted to the emergency department due to sudden chest pain and signs of congestive heart failure for weeks. Echocardiography in the emergency department showed lateral wall hypokinesis and severe mitral regurgitation. Coronary angiography revealed a small collateral branch occlusion unsuitable for revascularization. On the first day of hospitalization, the patient developed an acute ischemia of the left lower limb, for which he underwent revascularization surgery. After the thrombectomy, the patient presented with fever, for which prophylactic antibiotics were started while awaiting investigation into surgical and cystic complications, such as infection, which were ruled out. Once stabilized, a second transthoracic echocardiogram confirmed the severe mitral regurgitation and prolapse due to posterior mitral valve flail, suggesting long-term primary mitral valve disease as the underlying mechanism for regurgitation. The patient underwent surgical mitral valve repair, which was complicated by suture dehiscence.  The severe mitral valve regurgitation was attributed to ADPKD, given the patient's family history, age, and typical cardiovascular findings and multiple renal and hepatic cysts observed. Further investigation into primary mitral valve disorders, such as soft connective tissue diseases like Marfan syndrome, was not deemed necessary.

Deep learning-based segmentation of kidneys and renal cysts on T2-weighted MRI from patients with autosomal dominant polycystic kidney disease

BACKGROUND

Our aim was to train and test a deep learning-based algorithm for automatically segmenting kidneys and renal cysts in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

We retrospectively selected all ADPKD patients who underwent renal MRI with coronal T2-weighted imaging at our institution from 2008 to 2022. The 20 most recent examinations constituted the test dataset, to mimic pseudoprospective enrolment. The remaining ones constituted the training dataset to which eight normal renal MRIs were added. Kidneys and cysts ground truth segmentations were performed on coronal T2-weighted images by a junior radiologist supervised by an experienced radiologist. Kidneys and cysts of the 20 test MRIs were segmented by the algorithm and three independent human raters. Segmentations were compared using overlap metrics. The total kidney volume (TKV), total cystic volume (TCV), and cystic index (TCV divided by TKV) were compared using Bland-Altman analysis.

RESULTS

We included 164 ADPKD patients. Dice similarity coefficients ranged from 85.9% to 87.4% between the algorithms and the raters' segmentations and from 84.2% to 86.2% across raters' segmentations. For TCV assessment, the biases ± standard deviations (SD) were 3-19 ± 137-151 mL between the algorithm and the raters, and 22-45 ± 49-57 mL across raters. The algorithm underestimated TKV and TCV in two outliers with TCV > 2800 mL. For cystic index assessment, the biases ± SD were 2.5-6.9% ± 6.7-8.3% between the algorithm and the raters, and 2.1-9.4 ± 7.4-11.6% across raters.

CONCLUSION

The algorithm's performance fell within the range of inter-rater variability, but large TKV and TCV were underestimated.

RELEVANCE STATEMENT

Accurate automated segmentation of the renal cysts will enable the large-scale evaluation of the prognostic value of TCV and cystic index in ADPKD patients. If these biomarkers are prognostic, then automated segmentation will facilitate their use in daily routine.

KEY POINTS

Cystic volume is an emerging biomarker in ADPKD. The algorithm's performance in segmenting kidneys and cysts fell within interrater variability. The segmentation of very large cysts, under-represented in the training dataset, needs improvement.

New Mutation Associated with Polycystic Kidney Disease Type I: A Case Report

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most prevalent heritable disorders, characterized by the progressive development of kidney cysts leading to renal failure. It is primarily caused by mutations in the PKD1 and PKD2 genes, which account for approximately 85% and 15% of cases, respectively. This case report describes a previously unreported mutation in the PKD1 gene, identified in a family involving an aunt and her niece with ADPKD.

CASE PRESENTATION

The index case, a 56-year-old female with chronic kidney disease stage 3b secondary to ADPKD and hypertension, exhibited a strong family history of polycystic kidney disease (PKD). Initial genetic evaluations did not identify any recognized pathogenic mutations, leading to a more detailed investigation which revealed a novel mutation in the PKD1 gene. This mutation was also found in her niece, who presented with early-onset disease.

CONCLUSIONS

The identification of a heterozygous six-nucleotide deletion, c.2084_2089del, resulting in the in-frame deletion of two amino acids, p.Pro695_Ala696del, in the PKD1 gene, has been linked with ADPKD in these patients. This report emphasizes the need for continuous updates to genetic data for a deeper understanding of the diagnosis and prognosis of ADPKD that could potentially aid in targeted therapy.

Update on the Application of Ultrasonography in Understanding Autosomal Dominant Polycystic Kidney Disease

With an estimated prevalence of 1 in 1000 individuals globally, autosomal dominant polycystic kidney disease (ADPKD) stands as the most prevalent inherited renal disorder. Ultrasonography (US) is the most widely used imaging modality in the diagnosis and monitoring of ADPKD. This review discusses the role of US in the evaluation of ADPKD, including its diagnostic accuracy, limitations, and recent advances. An overview of the pathophysiology and clinical manifestations of ADPKD has also been provided. Furthermore, the potential of US as a noninvasive tool for the assessment of disease progression and treatment response is examined. Overall, US remains an essential tool for the management of ADPKD, and ongoing research efforts are aimed at improving its diagnostic and prognostic capabilities.

Prevalence and outcomes of polycystic kidney disease in African populations: A systematic review

BACKGROUND

Polycystic kidney disease (PKD) is the most common genetic cause of kidney disease. It is a progressive and irreversible condition that can lead to end-stage renal disease and many other visceral complications. Current comprehensive data on PKD patterns in Africa is lacking.

AIM

To describe the prevalence and outcomes of PKD in the African population.

METHODS

A literature search of PubMed, African journal online, and Google Scholar databases between 2000 and 2023 was performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were followed to design the study. Clinical presentations and outcomes of patients were extracted from the included studies.

RESULTS

Out of 106 articles, we included 13 studies from 7 African countries. Ten of them were retrospective descriptive studies concerning 943 PKD patients with a mean age of 47.9 years. The accurate prevalence and incidence of PKD were not known but it represented the third causal nephropathy among dialysis patients. In majority of patients, the diagnosis of the disease was often delayed. Kidney function impairment, abdominal mass, and hypertension were the leading symptoms at presentation with a pooled prevalence of 72.1% (69.1-75.1), 65.8% (62.2-69.4), and 57.4% (54.2-60.6) respectively. Hematuria and infections were the most frequent complications. Genotyping was performed in few studies that revealed a high proportion of new mutations mainly in the PKD1 gene.

CONCLUSION

The prevalence of PKD in African populations is not clearly defined. Clinical symptoms were almost present with most patients who had kidney function impairment and abdominal mass at the diagnostic. Larger studies including genetic testing are needed to determine the burden of PKD in African populations.

Transcriptomic profiling of Polycystic Kidney Disease identifies paracrine factors in the early cyst microenvironment

Initial cysts that are formed upon Pkd1 loss in mice impose persistent stress on surrounding tissue and trigger a cystic snowball effect, in which local aberrant PKD-related signaling increases the likelihood of new cyst formation, ultimately leading to accelerated disease progression. Although many pathways have been associated with PKD progression, the knowledge of early changes near initial cysts is limited. To perform an unbiased analysis of transcriptomic alterations in the cyst microenvironment, microdomains were collected from kidney sections of iKsp-Pkd1del mice with scattered Pkd1-deletion using Laser Capture Microdissection. These microdomains were defined as F4/80-low cystic, representing early alterations in the cyst microenvironment, F4/80-high cystic, with more advanced alterations, or non-cystic. RNA sequencing and differential gene expression analysis revealed 953 and 8088 dysregulated genes in the F4/80-low and F4/80-high cyst microenvironment, respectively, when compared to non-cystic microdomains. In the early cyst microenvironment, several injury-repair, growth, and tissue remodeling-related pathways were activated, accompanied by mild metabolic changes. In the more advanced F4/80-high microdomains, these pathways were potentiated and the metabolism was highly dysregulated. Upstream regulator analysis revealed a series of paracrine factors with increased activity in the early cyst microenvironment, including TNFSF12 and OSM. In line with the upstream regulator analysis, TWEAK and Oncostatin-M promoted cell proliferation and inflammatory gene expression in renal epithelial cells and fibroblasts in vitro. Collectively, our data provide an overview of molecular alterations that specifically occur in the cyst microenvironment and identify paracrine factors that may mediate early and advanced alterations in the cyst microenvironment.

The natural history of autosomal dominant polycystic kidney disease. A strategy for grouping families and mutations

Autosomal dominant polycystic kidney disease (ADPKD) is a main cause of end-stage renal disease. Today, knowledge of its genetic basis has made it possible to develop strategies that prevent the transmission of the disease.

OBJECTIVES

The objective of the study was to analyze the natural history of ADPKD in the province of Córdoba and to design a database that allows grouping families with different mutations.

PATIENTS AND METHODS

All patients (n = 678) diagnosed with ADPKD followed by the Córdoba nephrology service are included. Various clinical variables (age and sex), genetic variables (mutation in PKD1, PKD2) and the need for renal replacement therapy (RRT) were retrospectively analyzed.

RESULTS

The prevalence was 61 cases per 100,000 inhabitants. Median renal survival was significantly worse in PKD1 (57.5 years) than in PKD2 (70 years) (log-rank p = 0.000). We have genetically identified 43.8% of the population, detecting PKD1 mutations in 61.2% and PKD2 mutations in 37.4% of cases, respectively. The most frequent mutation, in PKD2 (c.2159del), appeared in 68 patients belonging to 10 different families. The one with the worst renal prognosis was a truncating mutation in PKD1 (c.9893 G > A). These patients required RRT at a median age of 38.7 years.

CONCLUSIONS

Renal survival of ADPKD in the province of Córdoba is similar to that described in the literature. We detected PKD2 mutations in 37.4% of cases. This strategy allows us to know the genetic basis of a large proportion of our population while saving resources. This is essential to be able to offer primary prevention of ADPKD through preimplantation genetic diagnosis.

Genetic Kidney Diseases (GKDs) Modeling Using Genome Editing Technologies

Genetic kidney diseases (GKDs) are a group of rare diseases, affecting approximately about 60 to 80 per 100,000 individuals, for which there is currently no treatment that can cure them (in many cases). GKDs usually leads to early-onset chronic kidney disease, which results in patients having to undergo dialysis or kidney transplant. Here, we briefly describe genetic causes and phenotypic effects of six GKDs representative of different ranges of prevalence and renal involvement (ciliopathy, glomerulopathy, and tubulopathy). One of the shared characteristics of GKDs is that most of them are monogenic. This characteristic makes it possible to use site-specific nuclease systems to edit the genes that cause GKDs and generate in vitro and in vivo models that reflect the genetic abnormalities of GKDs. We describe and compare these site-specific nuclease systems (zinc finger nucleases (ZFNs), transcription activator-like effect nucleases (TALENs) and regularly clustered short palindromic repeat-associated protein (CRISPR-Cas9)) and review how these systems have allowed the generation of cellular and animal GKDs models and how they have contributed to shed light on many still unknown fields in GKDs. We also indicate the main obstacles limiting the application of these systems in a more efficient way. The information provided here will be useful to gain an accurate understanding of the technological advances in the field of genome editing for GKDs, as well as to serve as a guide for the selection of both the genome editing tool and the gene delivery method most suitable for the successful development of GKDs models.

Incidental occurrence of papillary renal cell carcinoma in the native kidney with autosomal dominant polycystic kidney disease after renal transplantation: A case report

Autosomal dominant polycystic kidney disease (ADPKD) is one of the best-known genetic diseases. Almost half of the patients with ADPKD will develop end-stage renal disease, and the majority of patients are treated with renal transplantation. The current study presents a case that developed papillary renal cell carcinoma (PRCC) in the native right kidney 10 years after renal transplantation. PRCC is a not common malignant tumour entity (18.5% of all cases of renal cell carcinoma) compared with common clear cell renal carcinoma (65-70% of all cases of RCC).

Renal Transplantation from a Deceased Donor with Polycystic Kidney Disease

Renal transplantation is the gold standard treatment for patients with end-stage renal disease (ESRD) as it demonstrates improved long-term survival compared to patients who remain on renal replacement therapy. The widening gap between the demand and supply of organs warrants the expansion of donor criteria for renal transplantation. Kidneys with multiple cysts are often rejected for transplantation. Here, we present our recent experience of a 72-year-old patient with ESRD due to a biopsy-proven diabetic nephropathy who received a deceased donor kidney with adult polycystic kidney disease (APKD). At 31-month posttransplant, he had a serum creatinine of 1.6 mg/dL. Deceased donors affected by APKD should be considered an acceptable option for successful renal transplantation in select recipients, as well as an alternative kidney source to increase the donor pool.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

Laparoscopic Nephrectomy for Massive Kidneys in Polycystic Kidney Disease

Background and Objectives:

Laparoscopic nephrectomy is now considered a feasible surgical approach, even for large kidneys. In the case of massive kidneys, laparoscopy can be problematic, so that some authors suggest an open approach. However, previous studies have shown that hand-assisted laparoscopic nephrectomy (HALN) may represent a useful compromise.

We describe our hand-assisted laparoscopic technique for nephrectomy of large kidneys (> 2500 g) to encourage the use of laparoscopy for nephrectomy in autosomal dominant polycystic kidney disease.

Methods:

We retrospectively analyzed data from 26 nephrectomies in 17 patients who underwent HALN for ADPKD and compared them to a group of 22 nephrectomies in 18 patients with open surgical technique.

Results:

The duration of the procedure was significantly longer in the laparoscopic group, with a median of 180 minutes versus 90 minutes for the unilateral nephrectomies, and 240 minutes versus 122 minutes for the bilateral procedures. The median kidney weight in the open group was 2500 g (range 1300 – 4500 g), while the median weight in the HALN group was 2375 g (range 1000 – 4700 g). The median hospital stay was comparable. No significant differences were recorded in the intra- and postoperative complication rate.

Conclusion:

Hand-assisted laparoscopic nephrectomy can be considered a technique of choice for patients suffering from ADPKD requiring nephrectomy, also with massive kidneys weighing more than 3500 g. Compared to open nephrectomy, HALN can be performed safely, with reasonably longer operating times and without major complications, and offers a significant reduction in hospitalization time, pain and postoperative discomfort.

Simultaneous bilateral laparoscopic nephrectomy with kidney transplantation in patients with ESRD due to ADPKD: A single-center experience

Patients with autosomal dominant polycystic disease (ADPKD) may require bilateral nephrectomy (BN) in addition to kidney transplantation (KT) for symptom control. This study aims to compare simultaneous BNKT to contemporaneous controls by reviewing our cohort of ADPKD patients who underwent KT from a living donor from January 2014 to October 2019. Symptomatic patients who underwent laparoscopic BNKT were compared to KT alone. Clinical differences related to undertaking bilateral nephrectomies showed increased total kidney volumes (P < .001). We assessed operative parameters, complications, and clinical outcomes. The complications were classified according to the Clavien-Dindo system. In 148 transplant recipients, 51 underwent BNKT, and 97 KT alone. There was no difference in baseline demographics. BNKT recipients had longer cold ischemia time, required more ICU care, increased blood transfusions and longer hospital stays. The kidney function was similar in the first year in both groups, with no difference in delayed graft function, readmissions or severe grade III and IV complications within 3 months after surgery. Laparoscopic BNKT is safe and feasible at the time of living donor KT. Although higher acuity care is needed with a longer initial hospital stay, there are comparable posttransplant patient and allograft outcomes.

A 30% incidence of renal cysts with varying sizes and densities in biomedical research swine is not associated with renal dysfunction

BACKGROUND

Renal cystic disease arising from various etiologies results in fluid-filled cavities within the kidneys. Moreover, preexisting renal dysfunction has been shown to exacerbate multiple pathologies. While swine bred for biomedical research are often clinically inspected for illness/parasites, more advanced diagnostics may aid in uncovering underlying renal abnormalities.

METHODS

Computed tomography was performed in 54 female prepubertal Yorkshire swine to characterize renal cysts; urine and blood chemistry, and histology of cysts were also performed.

RESULTS

Digital reconstruction of right and left kidneys demonstrated that roughly one-third of the animals (17/54; 31%) had one or more renal cyst. Circulating biomarkers of renal function were not different between animals that had cysts and those that did not. Alternatively, urinary glucose (P = .03) was higher and sodium (P = .07) tended to be lower in animals with cysts compared to animals without, with no differences in protein (P = .14) or potassium (P = .20). Aspiration of cystic fluid was feasible in two animals, which revealed that the cystic fluid urea nitrogen (97.6 ± 28.7 vs 911.3 ± 468.2 mg/dL), potassium (29.8 ± 14.4 vs 148.2 ± 24.85 mmol/L), uric acid (2.55 ± 1.35 vs 11.4 ± 5.65 mg/dL), and creatinine (60.34 ± 17.26 vs 268.99 ± 95.79 mg/dL) were much lower than in the urine. Histology demonstrated a cyst that markedly compresses the adjacent cortex and is lined by a single layer of flattened epithelium, bounded by fibrous connective tissue which extends into the parenchyma. There is tubular atrophy and loss in these areas.

CONCLUSION

This study provides valuable insight for future studies focusing on kidney function in swine bred for biomedical research.

[Kidney Cysts and Cystic Nephropathies in Children - A Consensus Guideline by 10 German Medical Societies]

This consensus-based guideline was developed by all relevant German pediatric medical societies. Ultrasound is the standard imaging modality for pre- and postnatal kidney cysts and should also exclude extrarenal manifestations in the abdomen and internal genital organs. MRI has selected indications. Suspicion of a cystic kidney disease should prompt consultation of a pediatric nephrologist. Prenatal management must be tailored to very different degrees of disease severity. After renal oligohydramnios, we recommend delivery in a perinatal center. Neonates should not be denied renal replacement therapy solely because of their age. Children with unilateral multicystic dysplastic kidney do not require routine further imaging or nephrectomy, but long-term nephrology follow-up (as do children with uni- or bilateral kidney hypo-/dysplasia with cysts). ARPKD (autosomal recessive polycystic kidney disease), nephronophthisis, Bardet-Biedl syndrome and HNF1B mutations cause relevant extrarenal disease and genetic testing is advisable. Children with tuberous sclerosis complex, tumor predisposition (e. g. von Hippel Lindau syndrome) or high risk of acquired kidney cysts should have regular ultrasounds. Even asymptomatic children of parents with ADPKD (autosomal dominant PKD) should be monitored for hypertension and proteinuria. Presymptomatic diagnostic ultrasound or genetic examination for ADPKD in minors should only be done after thorough counselling. Simple cysts are very rare in children and ADPKD in a parent should be excluded. Complex renal cysts require further investigation.

Simultaneous Hand-assisted Laparoscopic Bilateral Native Nephrectomy and Kidney Transplantation for Patients With Large Polycystic Kidneys

OBJECTIVE

To describe our technique of simultaneous hand-assisted laparoscopic bilateral native nephrectomy (BNN) and kidney transplantation (KT) in patients with autosomal dominant polycystic kidney disease and present our experience.

MATERIALS AND METHODS

We retrospectively reviewed a cohort of adult ESRD patients with symptomatic autosomal dominant polycystic kidney disease who underwent a hand-assisted laparoscopic BNN at the time of KT. We reviewed patients' and donor characteristics, and perioperative and postoperative outcomes.

RESULTS

A total of 52 patients underwent hand-assisted laparoscopic BNN at the time of KT from January 2014 to October 2019. The median age of the recipients was 53.4 years, 57.7% were males, and the median body mass index was 29.0 kg/m². All but one received a kidney from a living donor and the majority (86.5%) were pre-emptive. One patient required a small bowel resection due to an intraoperative small bowel injury. There was no solid organ injury during the procedure. All patients showed immediate allograft function and a steady decline in serum creatinine. The median decline in the creatinine and hemoglobin on day 1 was 1.2 mg/dL (inter quartile range 0.6-2.3) and 2.2 g/dL (inter quartile range 1.4-3.0), respectively.

CONCLUSION

Simultaneous hand-assisted laparoscopic bilateral nephrectomy with KT through a modified Gibson incision is feasible and safe in the hands of an experienced laparoscopic surgeon without compromising allograft function.

The value of genotypic and imaging information to predict functional and structural outcomes in ADPKD

BACKGROUNDA treatment option for autosomal dominant polycystic kidney disease (ADPKD) has highlighted the need to identify rapidly progressive patients. Kidney size/age and genotype have predictive power for renal outcomes, but their relative and additive value, plus associated trajectories of disease progression, are not well defined.METHODSThe value of genotypic and/or kidney imaging data (Mayo Imaging Class; MIC) to predict the time to functional (end-stage kidney disease [ESKD] or decline in estimated glomerular filtration rate [eGFR]) or structural (increase in height-adjusted total kidney volume [htTKV]) outcomes were evaluated in a Mayo Clinic PKD1/PKD2 population, and eGFR and htTKV trajectories from 20-65 years of age were modeled and independently validated in similarly defined CRISP and HALT PKD patients.RESULTSBoth genotypic and imaging groups strongly predicted ESKD and eGFR endpoints, with genotype improving the imaging predictions and vice versa; a multivariate model had strong discriminatory power (C-index = 0.845). However, imaging but not genotypic groups predicted htTKV growth, although more severe genotypic and imaging groups had larger kidneys at a young age. The trajectory of eGFR decline was linear from baseline in the most severe genotypic and imaging groups, but it was curvilinear in milder groups. Imaging class trajectories differentiated htTKV growth rates; severe classes had rapid early growth and large kidneys, but growth later slowed.CONCLUSIONThe value of imaging, genotypic, and combined data to identify rapidly progressive patients was demonstrated, and reference values for clinical trials were provided. Our data indicate that differences in kidney growth rates before adulthood significantly define patients with severe disease.FUNDINGNIDDK grants: Mayo DK058816 and DK090728; CRISP DK056943, DK056956, DK056957, and DK056961; and HALT PKD DK062410, DK062408, DK062402, DK082230, DK062411, and DK062401.

Stone Prevalence in Autosomal Dominant Polycystic Kidney Disease: A Systematic Review and Meta-Analysis

Background:

It is uncertain how often patients with autosomal dominant polycystic kidney disease (ADPKD) develop kidney stones.

Objective:

To review English-language studies reporting the incidence and prevalence of stones and stone interventions in adults with ADPKD.

Design:

Systematic review and meta-analysis.

Setting:

Any country of origin.

Patients:

Adult patients with ADPKD.

Measurements:

Incidence or prevalence of kidney stones and stone interventions.

Methods:

We reviewed 1812 citations from bibliographic databases, abstracted data from 49 eligible studies, and assessed methodological quality in duplicate. In some studies, the proportion of adults with ADPKD with the outcome were compared to adults without ADPKD; for these studies, prevalence risk ratios were calculated and pooled using a random effects model.

Results:

We identified 49 articles that met our review criteria. The methodological quality of many studies was limited (scores ranging from 2 to 14 out of 22, with a higher score indicating higher quality). No study clearly reported stone incidence, and in the cross-sectional studies, the definition of stones was often unclear. The prevalence of stones ranged from 3% to 59%, and a prevalence of stone interventions ranged from 1% to 8%; the average patient age at the time of assessment ranged from 26 to 61 years across the studies. Two studies reported a nonstatistically significant higher stone prevalence in patients with ADPKD compared to unaffected family members. Compared to unaffected family members, patients with ADPKD had a higher prevalence of kidney stones (6 cross-sectional studies; unadjusted prevalence ratio: 1.8; 95% confidence interval: 1.3 to 2.6; P = .0007; test for heterogeneity: I² = 0%, P = .8).

Limitations:

Studies were limited to articles published in English.

Conclusions:

The prevalence of kidney stones and stone interventions in adults with ADPKD remains uncertain. Future studies of higher methodological quality are needed to better characterize the incidence and prevalence of kidney stones in patients with ADPKD.

Trial registration:

We did not register the protocol for this systematic review.

Prevalence, risk factors and disease knowledge of polycystic kidney disease in Pakistan

Polycystic kidneys disease refers to cyst(s) formation in kidneys with severe consequences of end stage renal disease thus have higher mortality. It is a common genetic disease occurring either as autosomal dominant polycystic kidney (ADPKD) or autosomal recessive polycystic kidney disease (ARPKD) with prevalence rates of 1/1000 and 1/40,000 respectively. Dominant forms presenting in later (>30) while recessive in earlier ages (infancy) and affecting both sexes and almost all race. The patient experiences many renal as well as extra-renal manifestations with marked hypertension and cyst formation in other organs predominantly in liver. Due to genetic basis, positive family history is considered as major risk factor. Ultrasonography remains the main stay of diagnosis along with family history, by indicating increased renal size and architectural modifications. Initially disease remains asymptomatic, later on symptomatic treatment is suggested with surgical interventions like cyst decortications or drainage. Dialysis proved to be beneficial in end stage renal disease. However renal transplantation is the treatment of choice.

International consensus statement on the diagnosis and management of autosomal dominant polycystic kidney disease in children and young people

These recommendations were systematically developed on behalf of the Network for Early Onset Cystic Kidney Disease (NEOCYST) by an international group of experts in autosomal dominant polycystic kidney disease (ADPKD) from paediatric and adult nephrology, human genetics, paediatric radiology and ethics specialties together with patient representatives. They have been endorsed by the International Pediatric Nephrology Association (IPNA) and the European Society of Paediatric Nephrology (ESPN). For asymptomatic minors at risk of ADPKD, ongoing surveillance (repeated screening for treatable disease manifestations without diagnostic testing) or immediate diagnostic screening are equally valid clinical approaches. Ultrasonography is the current radiological method of choice for screening. Sonographic detection of one or more cysts in an at-risk child is highly suggestive of ADPKD, but a negative scan cannot rule out ADPKD in childhood. Genetic testing is recommended for infants with very-early-onset symptomatic disease and for children with a negative family history and progressive disease. Children with a positive family history and either confirmed or unknown disease status should be monitored for hypertension (preferably by ambulatory blood pressure monitoring) and albuminuria. Currently, vasopressin antagonists should not be offered routinely but off-label use can be considered in selected children. No consensus was reached on the use of statins, but mTOR inhibitors and somatostatin analogues are not recommended. Children with ADPKD should be strongly encouraged to achieve the low dietary salt intake that is recommended for all children.

Targeted Therapies for Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening genetic disease in humans, affecting approximately 1 in 500 people. ADPKD is characterized by cyst growth in the kidney leading to progressive parenchymal damage and is the underlying pathology in approximately 10% of patients requiring hemodialysis or transplantation for end-stage kidney disease. The two proteins that are mutated in ADPKD, polycystin-1 and polycystin-2, form a complex located on the primary cilium and the plasma membrane to facilitate calcium ion release in the cell. There is currently no Food and Drug Administration (FDA)-approved therapy to cure or slow the progression of the disease. Rodent ADPKD models do not completely mimic the human disease, and therefore preclinical results have not always successfully translated to the clinic. Moreover, the toxicity of many of these potential therapies has led to patient withdrawals from clinical trials.

RESULTS

Here, we review compounds in clinical trial for treating ADPKD, and we examine the feasibility of using a kidney-targeted approach, with potential for broadening the therapeutic window, decreasing treatment-associated toxicity and increasing the efficacy of agents that have demonstrated activity in animal models. We make recommendations for integrating kidney- targeted therapies with current treatment regimes, to achieve a combined approach to treating ADPKD.

CONCLUSION

Many compounds are currently in clinical trial for ADPKD yet, to date, none are FDA-approved for treating this disease. Patients could benefit from efficacious pharmacotherapy, especially if it can be kidney-targeted, and intensive efforts continue to be focused on this goal.

GANAB and PKD1 Variations in a 12 Years Old Female Patient With Early Onset of Autosomal Dominant Polycystic Kidney Disease

Autosomal Dominant Polycystic Kidney Disease (ADPKD) typically results from a mutation in the PKD1 and PKD2 genes, which code for polycystin-1 (PC1) and polycystin-2 (PC2), respectively. Mutations in these genes promote renal cystic dysplasia and are a significant cause of End-Stage Kidney Disease (ESKD). Polycystic kidney disease-3 (PKD3), another form of ADPKD, is caused by mutations in glucosidase II alpha subunit (GANAB) gene and present in mid- and late adulthood. We report a description of an ADPKD case in a 12-year-old female presented bilateral renal cysts in adolescence. Two mutations in two genes PKD1 and GANAB were identified by targeted capture and next-generation sequencing (NGS) on an Illumina sequencing system. The identified PKD1 mutation p.Pro61Leu: c.182C > T (CCC > CTC) a missense type of uncertain clinical significance. However, the identified PKD1 mutation can alter transcription factors motifs and consequently disturb the transcription process. The second mutation identified in GANAB locus, p.Arg61Ter: c.181C > T, a nonsense type, CGA > TGA. The mutation is unreported pathogenic variant can cause loss of the glucosidase II alpha subunit normal protein function. Both the patient father and paternal grandmother had a history of ADPKD but never were tested. This case is the first case of combine presentation on PKD1 and PKD3 in a pediatric patient with nephrolithiasis.

Polycystic kidney disease

Cystic kidneys are common causes of end-stage renal disease, both in children and in adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are cilia-related disorders and the two main forms of monogenic cystic kidney diseases. ADPKD is a common disease that mostly presents in adults, whereas ARPKD is a rarer and often more severe form of polycystic kidney disease (PKD) that usually presents perinatally or in early childhood. Cell biological and clinical research approaches have expanded our knowledge of the pathogenesis of ADPKD and ARPKD and revealed some mechanistic overlap between them. A reduced 'dosage' of PKD proteins is thought to disturb cell homeostasis and converging signalling pathways, such as Ca²⁺, cAMP, mechanistic target of rapamycin, WNT, vascular endothelial growth factor and Hippo signalling, and could explain the more severe clinical course in some patients with PKD. Genetic diagnosis might benefit families and improve the clinical management of patients, which might be enhanced even further with emerging therapeutic options. However, many important questions about the pathogenesis of PKD remain. In this Primer, we provide an overview of the current knowledge of PKD and its treatment.

Should kidney volume be used as an indicator of surgical occasion for patients with autosomal dominant polycystic kidney disease?

To investigate the best surgical occasion of laparoscopic cyst decortications (LCDs) in patients with autosomal dominant polycystic kidney disease (ADPKD), in accordance with the renal volume (RV). We retrospectively analyzed 135 (65 male and 70 female) patients with ADPKD who underwent LCD between June 2011 and October 2015. Patients were divided into 4 groups according to the volume of the operated kidney measured from computed tomography scans: group A (28 patients, RV < 500 mL), group B (63 patients, RV = 500-1000 mL), group C (30 patients, RV = 1000-1500 mL), and group D (14 patients, RV > 1500 mL). We studied postoperative indicators at least 1-year follow-up. For each RV group, therapeutic responses of LCD in these patients with ADPKD were assessed by improvement of clinical parameters and manifestations. A significant glomerular filtration rate (GFR) improvement was found in RV group B (31.8 ± 11.1 mL/min; final GFR 36.9 ± 12.7 mL/min; P < 0.01), and RV group C (21.1 ± 8.7 mL/min; final GFR 27.4 ± 9.2 mL/min; P < 0.01). RV group C had much higher GFR improvements than did RV group B (P < 0.01). In addition, refractory pain in patients of RV groups B, C, and D was much relieved by LCD treatment. Compared with other RV groups, blood pressures in patients with ADPKD of RV group D were also improved (P < 0.01). Our study indicates that RV could be used to evaluate LCD clinical outcomes in patients with ADPKD. The results of LCD for patients with ADPKD with RV between 500 and 1500 mL were encouraging, especially with regards to renal function improvement and pain relief. Therefore, RV may become a useful marker to predict the timing of LCD surgery in patients with ADPKD.

Outcomes of renal transplant from donors with polycystic kidney disease

INTRODUCTION

Kidneys from donors affected by autosomal-dominant polycystic kidney disease (ADPKD) are, in general, considered unsuitable for transplantation. However, some authors report cases of patients who received kidneys from a deceased ADPKD donor showing encouraging outcomes. Our aim is to provide our experience of a patient with end stage renal failure who received a deceased donor kidney from a 29-year-old who themselves had been diagnosed with ADPKD but well maintained renal function, and to provide a comprehensive review of all the published literature.

METHODS

In addition to our case, a literature search (PubMed database, Embase, Cochrane Library) of articles published between 1980 and 2017 was performed.

RESULTS

Sixteen cases were identified. Median donor age was 24 (range12-55) years old. Median recipient age was 46 (range 19-72) years old. Fifteen cases had a single kidney transplant and one case had a dual kidney transplant. 13/16 (81%) had immediate function, 2 patients (12.5%) had delayed graft function and one patient (6.25%) had primary non-function. Median graft follow up was 36 months (range 6-180). Median serum creatinine at last follow up was 124 μmol/L (range75-442). Thirteen patients (81%) were still alive with a working renal transplant at last follow up.

CONCLUSION

The published literature is encouraging and supports the use of polycystic kidneys from younger deceased donors. Therefore, we believe that if kidneys from ADPKD donors are offered, they should have a full assessment and be considered acceptable for renal donation to recipients who may have a life expectancy of 10 years or less and who are fully informed and have the capacity to consent to receiving a polycystic kidney.

Kidney dysfunction following adrenalectomy in autosomal dominant polycystic kidney disease complicated with primary aldosteronism: A case report

The present study reported a case of autosomal dominant polycystic kidney disease complicated with primary aldosteronism in a 49-year-old woman. The patient was referred for refractory hypertension. Laboratory examinations revealed low potassium and renin levels. Computed tomography indicated a right adrenal tumor and multiple renal cysts. Adrenal vein sampling revealed a high aldosterone level on the side of the tumor. The patient was diagnosed with autosomal dominant polycystic kidney disease complicated by primary aldosteronism and adrenalectomy was performed. Over the following 7 months, the estimated glomerular filtration rate decreased from 76 to 48 ml/min/1.73 m², which was attributed to glomerular hyperfiltration correction induced by hyperaldosteronism remission, indicating kidney dysfunction. Clinicians must therefore monitor for the unmasking of kidney dysfunction following adrenalectomy in such cases.

Cystic Diseases of Childhood: A Review

Renal cystic lesions are considered the most common abnormality associated with the kidneys. Most renal cysts are usually uncomplicated simple cysts that are not life-threatening; however, fatal renal cystic diseases can develop from these space-occupying lesions. Although renal cystic diseases are similar in presentation, they possess distinct features, variable prognoses, and complications later in life. Early identification and effective management of these respected diseases has led to longer survival rates and better quality of life. The purpose of this review is to provide a comprehensive analysis of the most prevalent cystic diseases of the pediatric population in hopes to aid in early distinction and appropriate treatment.

Case report of renal pelvis squamous cell carcinoma with tumor embolus in autosomal dominant polycystic kidney disease

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is a multisystem hereditary disease characterized by formation of cysts in the ductal organs. Renal pelvis malignancy in ADPKD is very rare and sporadically reported in the previous literature. Here, we report the first case of renal pelvis squamous cell carcinoma with tumor embolus in a 35-year-old ADPKD patient. The patient presented with 3 months of persistent backache and intermittent fever, and was initially diagnosed as intracystic hemorrhage with inferior vena cava thrombosis formation. As a result, he received anticoagulation therapy in a local hospital. However, his backache got worsened during the therapy, and he lost 10 kg of his body weight from the onset of illness. In our hospital, computed tomography demonstrated a heterogeneous right renal mass as well as emboli in the inferior vena cava and bilateral renal veins. Positron emission tomography computed tomography and biopsy were also performed, but the results were equivocal. Considering the patient's willingness and the potential malignancy, we performed thoracoabdominal nephrectomy and embolectomy, and histological examination made the diagnosis of renal pelvis squamous cell carcinoma. After adjuvant chemotherapy including paclitaxel and carboplatin, the patient obtained improved physical status and was disease free at the 6-month follow-up. Although rare, renal pelvis squamous cell carcinoma should be considered in the differential diagnosis of renal mass in ADPKD patients.

CONCLUSION

Our case suggested surgery combined with adjuvant chemotherapy might be effective treatments in such a condition.

Graft Survival in Patients With Polycystic Kidney Disease With Nephrectomy of Native Kidney Pretransplant

INTRODUCTION

Autosomal-dominant polycystic disease (ADPKD) represents 5%-10% of cases of end-stage renal failure. However, management of these patients in terms of whether or not to perform a transplant and optimal timing remains controversial. The objective of our analysis was to evaluate graft survival in patients with ADPKD in which we conduct pretransplant nephrectomy.

METHODS

This retrospective study including renal transplant patients secondary to ADPKD in our hospital between January 2000 and December 2012. Pretransplant native kidney nephrectomy was indicated in cases of need for space or repeated complications (cysts). We compared the initial function and graft survival between groups of transplanted based on whether nephrectomy had been performed or not.

RESULTS

Eighty-seven patients underwent a kidney transplant owing to ADPKD; 62% (n = 54) were male, with an average age of 55.22 years. Twenty-seven patients (30%) underwent nephrectomy native kidneys before transplantation. There were no serious postoperative complications. Patients who underwent nephrectomy (group 1) showed values of creatinine of 1.57 and 1.50 mg/dL at 3 and 6 months, respectively. In the no nephrectomy group, these values were 2.03 and 1.83 mg/dL, respectively. Graft survival after the first year was of 98% for group 1 and 95% for group 2. The 5-year implant survival was 95% and 80%, respectively.

CONCLUSIONS

Native kidney nephrectomy before transplantation in ADPKD is safe in an experienced center, both in terms of surgery-related morbidity and mortality and graft survival and function.

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.

Pravastatin Therapy and Biomarker Changes in Children and Young Adults with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND OBJECTIVES

Disease-specific treatment options for autosomal dominant polycystic kidney disease are limited. Clinical intervention early in life is likely to have the greatest effect. In a 3-year randomized double-blind placebo-controlled phase 3 clinical trial, the authors recently showed that pravastatin decreased height-corrected total kidney volume (HtTKV) progression of structural kidney disease over a 3-year period. However, the underlying mechanisms have not been elucidated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Participants were recruited nationally from July 2007 through October 2009. Plasma and urine samples collected at baseline, 18 months, and 36 months from 91 pediatric patients enrolled in the above-mentioned clinical trial were subjected to mass spectrometry-based biomarker analysis. Changes in biomarkers over 3 years were compared between placebo and pravastatin-treated groups. Linear regression was used to evaluate the changes in biomarkers with the percent change in HtTKV over 3 years.

RESULTS

Changes in plasma concentrations of proinflammatory and oxidative stress markers (9- hydroxyoctadecadienoic acid, 13-hydroxyoctadecadienoic acid, and 15-hydroxyeicosatetraenoic acid [HETE]) over 3 years were significantly different between the placebo and pravastatin-treated groups, with the pravastatin group showing a lower rate of biomarker increase. Urinary 8-HETE, 9-HETE, and 11-HETE were positively associated with the changes in HtTKV in the pravastatin group.

CONCLUSIONS

Pravastatin therapy diminished the increase of cyclooxygenase- and lipoxygenase-derived plasma lipid mediators. The identified biomarkers and related molecular pathways of inflammation and endothelial dysfunction may present potential targets for monitoring of disease severity and therapeutic intervention of autosomal dominant polycystic kidney disease.

Four-dimensional MRI of renal function in the developing mouse

The major roles of filtration, metabolism and high blood flow make the kidney highly vulnerable to drug-induced toxicity and other renal injuries. A method to follow kidney function is essential for the early screening of toxicity and malformations. In this study, we acquired high spatiotemporal resolution (four dimensional) datasets of normal mice to follow changes in kidney structure and function during development. The data were acquired with dynamic contrast-enhanced MRI (via keyhole imaging) and a cryogenic surface coil, allowing us to obtain a full three-dimensional image (isotropic resolution, 125 microns) every 7.7 s over a 50-min scan. This time course permitted the demonstration of both contrast enhancement and clearance. Functional changes were measured over a 17-week course (at 3, 5, 7, 9, 13 and 17 weeks). The time dimension of the MRI dataset was processed to produce unique image contrasts to segment the four regions of the kidney: cortex (CO), outer stripe (OS) of the outer medulla (OM), inner stripe (IS) of the OM and inner medulla (IM). Local volumes, time-to-peak (TTP) values and decay constants (DC) were measured in each renal region. These metrics increased significantly with age, with the exception of DC values in the IS and OS. These data will serve as a foundation for studies of normal renal physiology and future studies of renal diseases that require early detection and intervention.

Laparoscopic pretransplant nephrectomy with morcellation in autosomic-dominant polycystic kidney disease patients with end-stage renal disease

BACKGROUND

Laparoscopic nephrectomy (LN) in end-stage autosomic-dominant polycystic kidney disease (ADPKD) requires a large abdominal incision for the specimen extraction.

OBJECTIVE

The objective of this study was to describe our technique of LN for end-stage ADPKD followed by morcellation (LNM) of the specimen and extraction through a minimal abdominal incision.

METHODS

The medical records of 19 consecutive patients who underwent pretransplant LNM between 2008 and 2011 by a single experienced laparoscopic surgeon were analyzed. Morcellation was performed with the Gynecare Morcellex™ Tissue morcellator, Ethicon.

RESULTS AND LIMITATIONS

All cases but one were completed laparoscopically. Mean specimen weight was 1,026.8 g. Mean duration of the procedure, estimated blood loss, and hospital stay were 131.3 min, 52.1 ml, and 7.9 days, respectively. Specimens were extracted through a 12-mm trocar in 10/18 patients and through a 3-cm incision in 9/18 cases. Postoperatively, three complications were observed (Clavien grades II, I, and II). The only case of incisional hernia was observed in the converted procedure. Major limitation of the study is its retrospective design.

CONCLUSIONS

In our preliminary series and in the hands of a very experienced laparoscopist, LNM for ADPKD appears as a modern, mini-invasive, and safe technique. Specimen's extraction through a small abdominal incision reduces postoperative pain and incisional hernias and guarantees the final cosmetic result of laparoscopy. The reduced overall morbidity could reduce the period between nephrectomy and transplantation.

Renal transplantation and polycystic: surgical considerations

BACKGROUND

The indication and timing of nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) remain controversial, especially in patients who are candidates to renal transplantation (RT). The main surgical options such as unilateral vs. bilateral nephrectomy, nephrectomy before vs. after RT, or simultaneous nephrectomy and transplantation, are herein discussed.

OBJECTIVE

Evidence acquisition of the best surgical management available for ADPKD in the context of kidney transplantation.

ACQUISITION OF EVIDENCE

Systematic literature review in PubMed from 1978 to 2013 was conducted. Articles selected included:randomized controlled trials and cohort studies. Furthermore, well designed ADPKD reviews were considered for this study.

SYNTHESIS OF EVIDENCE

Laparoscopic nephrectomy in ADPKD is a safe procedure with an acceptable complication rate. Unilateral nephrectomy has advantages over the bilateral one regarding the perioperative complication rate. Although the timing of nephrectomy is controversial, it seems that simultaneous nephrectomy and renal transplantation does not increase surgical morbidity neither affect graft survival.

CONCLUSIONS

Simultaneous nephrectomy and RT appears to be an acceptable alternative to conventional two-stage procedure without any increased morbidity, in the context of ADPKD. Furthermore, laparoscopic nephrectomy performed in experienced centres is a safe alternative to conventional approach.

Hand-assisted laparoscopic nephrectomy for polycystic kidney disease

BACKGROUND AND OBJECTIVES

Historically, nephrectomy for autosomal dominant polycystic kidney disease was performed by an open technique. We performed this study to compare outcomes in hand-assisted laparoscopic nephrectomy with open nephrectomy in this population.

METHODS

Charts of patients with autosomal dominant polycystic kidney disease who underwent nephrectomy by a transplant surgeon from January 1, 2000, to December 31, 2011, were reviewed. The hand-assisted laparoscopic nephrectomy group was compared with the open group. Data collected included unilateral versus bilateral nephrectomy, operative time, complications, transfusion requirement, and length of stay.

RESULTS

Of the 78 patients identified, 18 underwent open transabdominal nephrectomy, 56 underwent hand-assisted laparoscopic nephrectomy, and 2 underwent hand-assisted laparoscopic nephrectomy that was converted to an open procedure. Two patients were excluded because another major procedure was performed at the same time as the nephrectomy. Operative times were similar. Patients undergoing open bilateral nephrectomy were more likely to receive transfusion (odds ratio, 3.57 [95% confidence interval, 0.74-17.19]; P = .016), and the length of stay was longer in the open groups (5.9 days vs 4.0 days for unilateral [P = .013] and 7.8 days vs 4.6 days for bilateral [P = .001]). Overall complication rates were similar. The most frequent complications associated with hand-assisted laparoscopic nephrectomy were the development of an incisional hernia at the hand-port site and arteriovenous fistula thrombosis.

CONCLUSION

Hand-assisted laparoscopic nephrectomy can be safely performed without increased operative times or complications. The hand-assisted laparoscopic nephrectomy group enjoyed a shorter length of stay, and fewer patients in this group received transfusion. For patients considering renal transplantation, avoidance of transfusion is important to prevent sensitization and limiting access to compatible organs.

Simultaneous kidney transplantation and bilateral native nephrectomy for polycystic kidney disease

PURPOSE

Bilateral native nephrectomy with simultaneous kidney transplantation is becoming more common for patients with polycystic kidney disease in the living donor nephrectomy era. Single center reports evaluating the short-term and long-term outcomes of simultaneous kidney transplantation have been published but are generally limited by small sample sizes. We examined population level data to broadly define the complications of simultaneous kidney transplantation.

MATERIALS AND METHODS

The Nationwide Inpatient Sample (NIS) was used to acquire data on 2,368 patients with polycystic kidney disease treated with bilateral native nephrectomy between 1998 and 2010. We performed unadjusted, multivariable and propensity score adjusted analyses of postoperative outcomes.

RESULTS

A total of 2,368 patients were included in this study. The 271 patients (11.4%) who underwent simultaneous kidney transplantation had higher rates of intraoperative hemorrhage, blood transfusion and urological complications (propensity score adjusted OR 3.3, p=0.01, OR 4.2, p<0.0001 and OR 5.5, p<0.0001, respectively) but a lower in-hospital mortality rate (15.8% vs 1.1%, propensity score adjusted OR 0.10, p<0.0001). Median hospitalization was also significantly higher in patients who underwent simultaneous kidney transplantation (6 vs 9 days, p<0.0001). For the top quartile of high volume hospitals the rates of intraoperative hemorrhage, blood transfusion and urological complications remained statistically higher in patients treated with simultaneous kidney transplantation but in-hospital mortality was similar on multivariable logistic regression (OR 0.2, p=0.17).

CONCLUSIONS

Except for increased rates of intraoperative hemorrhage, blood transfusion and urological complications there were no significant differences in postoperative adverse outcomes in this large, population based study of patients who underwent simultaneous kidney transplantation compared to bilateral native nephrectomy alone.

Multiple postnatal craniofacial anomalies are characterized by conditional loss of polycystic kidney disease 2 (Pkd2)

Polycystin 2 (Pkd2), which belongs to the transient receptor potential family, plays a critical role in development. Pkd2 is mainly localized in the primary cilia, which also function as mechanoreceptors in many cells that influence multiple biological processes including Ca(2+) influx, chemical activity and signalling pathways. Mutations in many cilia proteins result in craniofacial abnormalities. Orofacial tissues constantly receive mechanical forces and are known to develop and grow through intricate signalling pathways. Here we investigate the role of Pkd2, whose role remains unclear in craniofacial development and growth. In order to determine the role of Pkd2 in craniofacial development, we located expression in craniofacial tissues and analysed mice with conditional deletion of Pkd2 in neural crest-derived cells, using Wnt1Cre mice. Pkd2 mutants showed many signs of mechanical trauma such as fractured molar roots, distorted incisors, alveolar bone loss and compressed temporomandibular joints, in addition to abnormal skull shapes. Significantly, mutants showed no indication of any of these phenotypes at embryonic stages when heads perceive no significant mechanical stress in utero. The results suggest that Pkd2 is likely to play a critical role in craniofacial growth as a mechanoreceptor. Pkd2 is also identified as one of the genes responsible for autosomal dominant polycystic kidney disease (ADPKD). Since facial anomalies have never been identified in ADPKD patients, we carried out three-dimensional photography of patient faces and analysed these using dense surface modelling. This analysis revealed specific characteristics of ADPKD patient faces, some of which correlated with those of the mutant mice.

Genetic diagnosis of autosomal dominant polycystic kidney disease by targeted capture and next-generation sequencing: utility and limitations

Mutation-based molecular diagnostics of autosomal dominant polycystic kidney disease (ADPKD) is complicated by genetic and allelic heterogeneity, large multi-exon genes, and duplication sequences of PKD1. Recently, targeted resequencing by pooling long-range polymerase chain reaction (LR-PCR) amplicons has been used in the identification of mutations in ADPKD. Despite its high sensitivity, specificity and accuracy, LR-PCR is still complicated. We performed whole-exome sequencing on two unrelated typical Chinese ADPKD probands and evaluated the effectiveness of this approach compared with Sanger sequencing. Meanwhile, we performed targeted gene and next-generation sequencing (targeted DNA-HiSeq) on 8 individuals (1 patient from one family, 5 patients and 2 normal individuals from another family). Both whole-exome sequencing and targeted DNA-HiSeq confirmed c.11364delC (p.H3788QfsX37) within the unduplicated region of PKD1 in one proband; in the other family, targeted DNA-HiSeq identified a small insertion, c.401_402insG (p.V134VfsX79), in PKD2. These methods do not overcome the screening complexity of homology. However, the true positives of variants confirmed by targeted gene and next-generation sequencing were 69.4%, 50% and 100% without a false positive in the whole coding region and the duplicated and unduplicated regions, which indicated that the screening accuracy of PKD1 and PKD2 can be largely improved by using a greater sequencing depth and elaborate design of the capture probe.

One hundred consecutive kidney transplantations with simultaneous ipsilateral nephrectomy in patients with autosomal dominant polycystic kidney disease

PURPOSE

Surgical management of autosomal dominant polycystic kidney disease (ADPKD) in patients awaiting renal transplantation is a challenging task.

METHODS

From 1998 to 2009, a total of 100 consecutive renal transplantations with simultaneous unilateral nephrectomy were performed in 59 men and 41 women with ADPKD and end-stage renal failure. About 38% received kidney allografts from living donors. The ipsilateral polycystic kidney was removed at the time of renal transplantation. Immunosuppressive therapy was not modified. Cold ischaemia time was 155 (38-204 min) versus 910 min (95-2760 min) for living versus deceased donor transplantation. Mean weight of removed kidneys was 2002 g (414-8850 g). Mean follow-up was 3.0 years (0.8-10.0 years).

RESULTS

Overall patient and graft survival were 97 and 96% at 1 year and 93 and 80% at 5 years, respectively. Serum creatinine at current follow-up was 1.49 (0.8-2.8) mg/dL. Surgical complications, which might be associated with simultaneous nephrectomy requiring re-operation, occurred in 12% (lymphocele 4%, hernia 4%, post-operative haematoma or bleeding 4%). None of the patients died peri-operatively.

CONCLUSION

Renal transplantation with simultaneous unilateral nephrectomy in ADPKD is a reasonable procedure for patients suffering from massively enlarged native kidneys.

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.

Calmodulin-sensitive adenylyl cyclases mediate AVP-dependent cAMP production and Cl- secretion by human autosomal dominant polycystic kidney cells

In autosomal dominant polycystic kidney disease (ADPKD), binding of AVP to the V2 receptor (V2R) increases cAMP and accelerates cyst growth by stimulating cell proliferation and Cl(-)-dependent fluid secretion. Basal cAMP is elevated in human ADPKD cells compared with normal human kidney (NHK) cells. V2R mRNA levels are elevated in ADPKD cells; however, AVP caused a greater increase in global cAMP in NHK cells, suggesting an intrinsic difference in cAMP regulation. Expression, regulatory properties, and receptor coupling of specific adenylyl cyclases (ACs) provide temporal and spatial regulation of the cAMP signal. ADPKD and NHK cells express mRNAs for all nine ACs. Ca(2+)-inhibited ACs 5 and 6 are increased in ADPKD cells, while Ca(2+)/CaM-stimulated ACs 1 and 3 are downregulated. ACs 1, 3, 5, and 6 were detected in cyst cells in situ, and codistribution with aquaporin-2 suggests that these cysts were derived from collecting ducts. To determine the contribution of CaM-sensitive ACs to AVP signaling, cells were treated with W-7, a CaM inhibitor. W-7 decreased AVP-induced cAMP production and Cl(-) secretion by ADPKD cells. CaMKII inhibition increased AVP-induced cAMP, suggesting that cAMP synthesis is mediated by AC3. In contrast, CaM and CaMKII inhibition in NHK cells did not affect AVP-induced cAMP production. Restriction of intracellular Ca(2+) switched the response in NHK cells, such that CaM inhibition decreased AVP-induced cAMP production. We suggest that a compensatory response to decreased Ca(2+) in ADPKD cells switches V2R coupling from Ca(2+)-inhibited ACs 5/6 to Ca(2+)/CaM-stimulated AC3, to mitigate high cAMP levels in response to continuous AVP stimulation.

Laparoscopic bilateral native nephrectomies with simultaneous kidney transplantation

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Extirpation of polycystic kidneys for various medical reasons has been performed using many different approaches in attempts to limit morbidity from such a large operation. In indicated patients, it has usually been offered in a staged approach with renal transplantation to avoid graft complications. We published the first case of simultaneous laparoscopic bilateral native nephrectomy with kidney transplant in 2008. The present study shows our continued experience with offering this minimally invasive, single surgery alternative. The results are comparable to a staged laparoscopic approach with significantly shorter total hospital stay and one recovery for the patient and his/her family.

OBJECTIVE

• To analyse the perioperative outcomes of native bilateral laparoscopic nephrectomy (BLN) with simultaneous kidney transplantation.

PATIENTS AND METHODS

• From November 2000 to April 2011, 37 patients were seen for renal failure secondary to autosomal-dominant polycystic kidney disease (ADPKD) and underwent renal transplant with native nephrectomies at a single tertiary academic centre. • In all, 15 patients underwent BLN for ADPKD followed by simultaneous kidney transplantation. • The other 22 patients underwent BLN for ADPKD with kidney transplant performed at a separate setting. • Demographic data, perioperative outcomes, complications regardless of need for intervention, and graft function were analysed in both groups.

RESULTS

• The combined surgery was completed without intraoperative complication in all cases. • The median total operative duration was 372 min, estimated blood loss was 300 mL with two patients requiring transfusion, and the median (range) hospital stay was 5 (3-7) days. • All patients had immediate graft function with additional relief of compressive symptoms. • In comparison to our staged cohort, the simultaneous group had a significantly shorter total hospital stay. • All other outcomes and complication rates were comparable.

CONCLUSION

• In ADPKD, a less invasive laparoscopic approach for native nephrectomies with simultaneous renal transplant offers comparable morbidity without graft compromise and the convenience of one operation and one recovery for the patient.