Citations

Key Points Automated cyst segmentation in autosomal dominant polycystic kidney disease could transform care by enabling precise monitoring of cyst progression with minimal manual effort. This technology can facilitate more consistent assessments of cyst burden across patients. Translating these segmentation models from magnetic resonance imaging to computed tomography is crucial for providing comprehensive, modality-independent evaluations. Background Total kidney and liver volumes are key image-based biomarkers to predict the severity of kidney and liver phenotype in autosomal dominant polycystic kidney disease (ADPKD). However, magnetic resonance (MR) imaging-based advanced biomarkers like total cyst number and cyst parenchyma surface area have been shown to more accurately assess cyst burden and improve the prediction of disease progression. The main aim of this study was to extend the calculation of advanced biomarkers to other imaging modalities; thus, we propose a fully automated model to segment kidney and liver cysts in computed tomography (CT) images. Methods Abdominal CTs of patients with ADPKD were gathered retrospectively between 2001 and 2018. A three-dimensional deep learning method using the nnU-Net architecture was trained to learn cyst edges-cores and the noncystic kidney/liver parenchyma. Separate segmentation models were trained for kidney cysts in contrast-enhanced CTs and liver cysts in noncontrast CTs using an active learning approach. Two experienced research fellows manually generated the reference standard segmentation, which were reviewed by an expert radiologist for accuracy. Results Two-hundred CT scans from 148 patients (mean age, 51.2±14.1 years; 48% male) were used for model training (80%) and testing (20%). In the test set, both models showed good agreement with the reference standard segmentations, similar to the agreement between two independent human readers (model versus reader: TCN kidney/liver r =0.96/0.97 and CPSA kidney r =0.98, inter-reader: TCN kidney/liver r =0.96/0.98 and CPSA kidney r =0.99). Conclusions Our study demonstrates that automated models can segment kidney and liver cysts accurately in CT scans of patients with ADPKD.

ABSTRACT Background This medical center migrated from alcohol to sotradecol foam sclerotherapy (SFS) because of perceived improved efficacy in managing symptomatic kidney and liver cysts. We report technical aspects, change in short- and long-term cyst volumes, patient-reported outcomes, safety and applications of the technique. Methods In this retrospective observational study, cases from January 2017 to December 2021 had TKCV/TLCV (per Targeted Kidney or Liver or Cyst analysis) segmented using a deep-learning algorithm and cyst segmentation software (pre-, post-procedure and longitudinally). TKCV/TLCV % change were evaluated using the one-sample Wilcoxon signed rank test. For analyses involving changes in cyst volumes, the median % change in cyst volume per patient was assessed. Longitudinal changes in cyst volumes were assessed using linear mixed models. Changes in quality of life (QOL) [Linear Analog Self-Assessment (LASA), Polycystic Liver Disease Quality of life Questionnaire (PLD-Q) and 12-item short-form (SF12)] were also assessed. Results There were 102 SFS sessions (38 kidney, 58 liver, 6 combined liver/kidney cysts) performed on 77 unique individuals included for analysis. Median [interquartile range (IQR)] % reductions in TKCV were –92.0% (IQR –98.2%, –82.7%, P < .001) and for TLCV were –83.1% (IQR –93.5%, –52.9%, P < .001). Among patients with multiple kidney procedures (n = 7), median % reduction in TKCV was –94.3% (IQR –96.6%, –92.4%, P = .023). For patients with multiple liver procedures (n = 11), median % reduction in TLCV was –63.3% (IQR –85.2%, –28.3%, P = .004). Results were similar among the four patients undergoing multi-stage procedures (n = 1 kidney, n = 3 liver). When measured longitudinally, both liver and kidney cyst volumes declined to levels near 0 mL by 1 year follow-up and remained stable several years later. LASA physical domain and PLD-Q QOL scores improved post-SFS procedure. Conclusion SFS led to substantial long-term reductions in TKCV/TLCV and improved QOL. SFS can augment cyst volume reduction in addition to tolvaptan (kidney cysts) and octreotide (liver cysts). In some individuals with large symptomatic cysts, multiple SFS procedures were safe and effective in reducing TLCV/TKCV and improving symptoms.

Tuberous sclerosis complex (TSC) is a highly variable autosomal dominant disease characterized by dysregulated organ development and growth. Benign tumors, termed hamartomas, may occur across organ systems but typically involve the kidney, brain, skin, heart, and lung. The diagnosis, surveillance, and clinical management of TSC requires a multidisciplinary approach, adopted by dedicated multispecialty centers worldwide. Nephrology involvement predominantly stems from the morbidity and mortality related to the prototypical kidney lesion, angiomyolipomas, whose presence and degree confers risk of CKD, hypertension, retroperitoneal bleeding, and possibly renal cell carcinoma. Surveillance of kidney structural lesions, kidney function, and BP may enable early interventions that limit kidney-related morbidity and mortality, such as mammalian target of rapamycin inhibitor therapy. We review the epidemiology, genetics, and pathogenesis of TSC and how these inform the evaluation, diagnosis, and clinical management of TSC from the vantage point of the treating nephrologist.

Abstract A variety of genetic diseases of the kidney tubule are amenable to correction via gene therapy. However, gene delivery to renal tubule epithelial cells mediated by viral vectors via the blood is inefficient due to the permselectivity of the glomerular barrier. We hypothesized that effacement of podocyte foot processes would disrupt typical glomerular limitations on filtration and make renal tubule epithelial cells susceptible to transduction from viral vectors delivered intravenously. We determined that adeno-associated virus serotype 8 (AAV8) transduced significantly more epithelial cells in the kidney under the conditions of LPS-induced proteinuria. Use of AAV1 in tandem with LPS-induced proteinuria yielded an ideal two-pronged effect of both partially detargeting the liver and transducing the kidney with a higher bioluminescent signal than AAV8 did, and at half of the dose. Using adenovirus serotype 5 (Ad5) in conjunction with LPS-induced proteinuria showed that kidney transduction was enhanced, but only in glomerular cells. These studies mechanistically test the efficacy of different viral vectors and demonstrate their capacity to transduce kidney epithelial cells. This is a fundamental step in designing future treatments for kidney gene therapy. Significance Statement The slit diaphragms in the glomerulus of the kidney are too narrow to allow most solute from the blood to enter the nephron. As a result, large particles such as viral vectors generally cannot access tubule epithelial cells necessary to correct genetic disorders. In this study, mice are induced into a state of proteinuria and subsequently administered viral vectors intravenously. This group of mice had higher levels of transduced kidney epithelial cells than the control (non-proteinuria) group. The induction of transient proteinuria before intravenous viral vector administration is a novel approach that could make tubulopathies treatable via gene therapy in both animal models and humans.

Currently, the vasopressin V2 receptor antagonist tolvaptan is the only approved treatment for autosomal dominant polycystic kidney disease (ADPKD). It has been suggested that vasopressin acting on V1a or V1b receptors may also affect its development. We show that a V1aR antagonist has no effect in an ADPKD mouse model (Pkd1RC/RC), whereas a V2R antagonist has a modest attenuating effect in female mice only. Neither potentiates or hinders the beneficial effect of tolvaptan when administered in combination with this drug.

Importance Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive development of kidney cysts and is the most common inherited kidney disorder worldwide. ADPKD accounts for 5% to 10% of kidney failure in the US and Europe, and its prevalence in the US is 9.3 per 10 000 individuals. Observations ADPKD is typically diagnosed in individuals aged 27 to 42 years and is primarily caused by pathogenic variants in the PKD1 (78%) or PKD2 (15%) genes. Most persons with ADPKD have an affected parent, but de novo disease is suggested in 10% to 25% of families. More than 90% of patients older than 35 years have hepatic cysts, which may cause abdominal discomfort and occasionally require medical or surgical intervention. Hypertension affects 70% to 80% of patients with ADPKD, and approximately 9% to 14% develop intracranial aneurysms, which have a rupture rate of 0.57 per 1000 patient-years. Approximately 50% of individuals with ADPKD require kidney replacement therapy by 62 years of age. The severity of kidney disease can be quantified using the Mayo Imaging Classification (MIC), which stratifies patients based on total kidney volume adjusted for height and age and ranges from 1A to 1E. Patients with MIC 1C to MIC 1E have larger kidneys because of more rapid growth (6%-10% per year) compared with those with MIC 1A and 1B (1%-5% per year) and have earlier progression to kidney replacement therapy, which occurs at a mean age of 58.4 years for MIC 1C, 52.5 years for MIC 1D, and 43.4 years for MIC 1E. Optimal management of ADPKD includes systolic blood pressure lower than 120 mm Hg for most patients, but lower than 110/75 mm Hg for patients with MIC 1C to 1E who have an estimated glomerular filtration rate (eGFR) greater than 60 mL/min/1.73 m 2 and are younger than 50 years, dietary sodium restriction (<2000 mg/d), weight management, and adequate hydration (>2.5 L daily). The vasopressin type 2 receptor antagonist tolvaptan reduces the annual rate of eGFR decline by 0.98 to 1.27 mL/min/1.73 m 2 and is indicated for patients with MIC 1C to 1E or an eGFR decline greater than 3 mL/min/1.73 m 2 per year to slow disease progression and delay the onset of kidney failure. Conclusion ADPKD is the most common genetic kidney disease worldwide and is characterized by progressive development of kidney cysts. Patients typically have hypertension and liver cysts, and 9% to 14% develop intracranial aneurysms. First-line treatment includes blood pressure control, dietary and weight management, and adequate hydration. Tolvaptan reduces the rate of eGFR decline for those at high risk of rapid progression to kidney failure.

Key Points Loss-of-function ALG8 and ALG9 variants were enriched in polycystic kidney/liver groups and International Classification of Diseases–coded cystic individuals in population cohorts. The ALG8 and ALG9 kidney phenotypes were usually mild to moderate, and lower eGFR or kidney failure was rare. ALG8 pathogenic variants sometimes resulted in severe polycystic liver disease. Background Autosomal dominant polycystic kidney disease (ADPKD) is a common, inherited nephropathy often resulting in kidney failure. It is genetically heterogeneous; along with the major genes, PKD1 and PKD2 , at least eight others have been suggested. ALG8 pathogenic variants have been associated with autosomal dominant polycystic liver disease and implicated in ADPKD, while ALG9 has been suggested as an ADPKD gene, but details of the phenotypes and penetrance are unclear. Methods We screened >3900 families with cystic kidneys and/or livers using global approaches to detect ALG8 or ALG9 pathogenic variants. In addition, population cohorts with sequence data (Genomics England 100K Genomics Project, UK Biobank, and Mayo Clinic Biobank [MCBB]) were screened for ALG8 / ALG9 pathogenic variants. Results Multicenter screening of individuals with polycystic kidney and/or liver disease identified 51 (1.3%) ALG8 (7 multiplex) and 23 (0.6%) ALG9 (5 multiplex) families—frequencies that were approximately 10× and approximately 24× greater than nonpolycystic kidney disease controls. Analysis of individuals with polycystic kidney disease phenotypes in 100K Genomics Project, UK Biobank, and MCBB identified nine ALG8 (0.39%) and nine ALG9 (0.39%) families, an enriched frequency over controls. Two individuals had PKD1 and ALG8 pathogenic changes. Eighty-nine percent of individuals with ALG8 mutations with imaging in the entire MCBB had kidney cysts (50%, >10 cysts), with greater median kidney and liver cyst numbers than controls. For ALG9, 78% had kidney cysts (27%, >10 cysts). Individuals with ALG8 mutations typically had mild cystic kidneys with limited enlargement. Liver cysts were common (71%), with enlarged livers (>2L) found in 11 of 62 patients, although surgical intervention was rare. The ALG9 kidney phenotype was also of mild cystic kidneys, but enlarged livers were rare; for both genes, CKD or kidney failure were rare. Conclusions ALG8 and ALG9 are defined as cystic kidney/liver genes but with limited penetrance for lower eGFR.

The Autosomal Dominant Polycystic Kidney Disease (ADPKD) Centers of Excellence (COE) Program, launched by the Polycystic Kidney Disease Foundation in 2022, aims to bridge the gap in specialized care for individuals with ADPKD. This program seeks to enhance the availability of specialized clinicians and simplify the process for patients seeking expert care. It is founded on three pillars: improving care for all individuals with ADPKD, educating and empowering the community, and advancing polycystic kidney disease research. The program draws inspiration from successful models in other diseases, such as cystic fibrosis and muscular dystrophy, which have demonstrated the effectiveness of standardized care centers in improving patient outcomes. Patient and clinician stakeholder interviews have identified key areas where a national program could make a significant effect, including the need for a core care team with defined referral processes, mentorship and shared care models, patient navigation services, and education around expert consensus and care guidelines. The program introduces two designations to accommodate diverse care settings and enhance patient access to specialists: COE and Partner Clinic. The Partner Clinic designation ensures that patients in smaller community practices have access to specialized care through mentorship and guidance from experts at COE. The program also emphasizes the importance of specialized services, especially in underserved communities experiencing health disparities, to manage the complexities of ADPKD care. Patient focus groups have highlighted the need for care navigation services, centralized sources of knowledge, and access to local care. The program aims to address these needs by providing a structured framework for care coordination, enhancing patient self-advocacy, and improving overall outcomes for individuals with ADPKD. Key Points The Autosomal Dominant Polycystic Kidney Disease Centers of Excellence Program aims to improve specialized care for autosomal dominant polycystic kidney disease patients. It introduces two designations to accommodate diverse care settings and enhance patient access to specialists: Center of Excellence and Partner Clinic. The program draws inspiration from successful models in other diseases, such as cystic fibrosis and muscular dystrophy, which have demonstrated the effectiveness of standardized care centers in improving patient outcomes. Key needs and programmatic goals identified through patient and clinician stakeholder interviews include establishing a core care team with defined referral processes, implementing mentorship and shared care models, providing patient navigation services, and offering education on expert consensus and care guidelines.