Advances in Autosomal Dominant Polycystic Kidney Disease: A Clinical Review

Glioneuronal tumor in an autosomal-dominant polycystic kidney disease patient: a case report and literature review

Introduction

The association between primary brain tumors, such as glioneuronal tumors, with autosomal-dominant polycystic kidney disease (ADPKD) remains poorly understood, with only two cases reported excluding this one. This case of an ADPKD patient diagnosed with a rosette-forming glioneuronal tumor highlights an exceptionally rare potential association warranting further investigation.

Case presentation

A 28-year-old male with ADPKD presented with progressive ataxia, dizziness, and headache. MRI revealed a cerebellar mass and obstructive hydrocephalus. Surgical resection and histopathological examination confirmed the diagnosis of a rosette-forming glioneuronal tumor. Postoperatively, the patient showed significant symptom improvement.

Discussion

The interplay between genetics and glioneuronal development is complex and underexplored. While most glioneuronal arise sporadically, rare genetic syndromes may predispose individuals to these tumors. Additionally, although more than 70 cases of ADPKD with concurrent tumors were reported, the literature on this specific association remains limited.

Conclusion

This case underscores the need for heightened awareness of potential associations between ADPKD and tumors such as glioneuronal tumors. With limited literature on this subject, further research is imperative to understand the underlying mechanisms and clinical implications. Enhancing our knowledge in this area can improve patient outcomes and management strategies.

Proteogenomics in Nephrology: A New Frontier in Nephrological Research

Proteogenomics represents a transformative intersection in nephrology, uniting genomics, transcriptomics, and proteomics to unravel the molecular intricacies of kidney diseases. This review encapsulates the methodological essence of proteogenomics and its profound implications in chronic kidney disease (CKD) research. We explore the proteogenomic pipeline, highlighting the integrated analysis of genomic, transcriptomic, and proteomic data and its pivotal role in enhancing our understanding of kidney pathologies. Through case studies, we showcase the application of proteogenomics in clear cell renal cell carcinoma (ccRCC) and Autosomal Recessive Polycystic Kidney Disease (ARPKD), emphasizing its potential in personalized treatment strategies and biomarker discovery. The review also addresses the challenges in proteogenomic analysis, including data integration complexities and bioinformatics limitations, and proposes solutions for advancing the field. Ultimately, this review underscores the prospective future of proteogenomics in nephrology, particularly in advancing personalized medicine and providing novel therapeutic insights.

Autosomal dominant polycystic kidney disease (ADPKD) with multiple complications: Management challenges

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary polycystic kidney disease characterized by renal enlargement, resulting in renal failure. In Indonesia, the exact prevalence of ADPKD is unknown due to limited reports on the disease. The aim of this study was to report a case of a patient with ADPKD with multiple complications. A 54-year-old male presented to the emergency room of Dr. Soetomo Academic General Hospital, Surabaya, Indonesia, with a chief complaint of dark-red-colored urine for one week. There was a progressive abdominal enlargement over the past five years, which had become more tense and rigid for the past one month. The patient had a history of fatigue and hypertension with routine follow-up. Physical examination on admission showed normal vital signs, and the abdominal assessment revealed a palpable hard mass approximately 4 cm in size in the right upper abdomen. Laboratory test indicated anemia, leukocytosis, lymphopenia, proteinuria, hematuria, leukocyturia, and elevated serum creatinine and urea levels. Abdominal imaging using ultrasonography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) revealed bilateral kidney and liver enlargement containing multiple cysts, suggesting polycystic kidney and liver disease. There was a ruptured cyst in the middle of the left kidney pole with minimal ascites found in the CT scan. The MRI exhibited the presence of multiple cysts in both kidneys, partially filled with blood. The patient was diagnosed with ADPKD, gross hematuria, acute or chronic kidney disease (CKD), urinary tract infection (UTI), normochromic-normocytic anemia, and metabolic acidosis. Dietary control with high-calorie, high-protein, and low-salt diet; fluid balance; and other symptomatic medications were initiated. It is critical to be aware of risk factors associated with the rapid progression of ADPKD in order to be able to provide a favorable impact on the disease prevention and management.

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.

Case Report: Autosomal dominant polycystic kidney disease and Wilms' tumor in infancy and childhood

Background

Autosomal dominant polycystic kidney disease (ADPKD) is rare but one of the most common inherited kidney diseases. Normal kidney function is maintained until adulthood in most patients. About 7 in 10 patients with ADPKD develop kidney failure in the latter half of their fifth decade of life. Wilms' tumor, or nephroblastoma, is the most common malignant tumor stemming from kidney cells in the pediatric age group. This type of tumor is the most frequently occurring kidney malignancy in children between the ages of 0 and 5 years. The exact cause of Wilms' tumor is unknown, though about 10% of cases have a genetic predisposition. Wilms' tumor is one of the most successfully treated childhood oncological diseases. Overall, the 5-year survival rates were approximately 90% in both the National Wilms Tumor Study (NWTS) and Paediatric Oncology SIOP studies, showing similar results.

Case presentation

We report a case of a girl diagnosed with autosomal polycystic kidney disease, who subsequently developed Wilms' tumor and underwent successful treatment with chemotherapy. Polycystic kidney disease was suspected in the fetus during prenatal ultrasound and confirmed after birth with ultrasound and genetic testing. The Wilms tumor was an accidental finding during abdominal MRI at the age of 2 years old to rule out liver pathology.

Conclusion

Reports on whether a diagnosis of ADPKD is a risk factor for malignancy are conflicting. In this particular case, Wilms' tumor is present in the background of polycystic kidney disease and was timely diagnosed by an incidental MRI.

Novel hits for autosomal dominated polycystic kidney disease (ADPKD) targeting derived by in silico screening on ZINC-15 natural product database

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disorder that leads to growth cysts in the kidney, ultimately resulting in loss of function. Currently, no effective drug therapy can be safely used in the clinic. So, looking for effective therapeutic drugs is urgent for treating ADPKD. Our natural product library was prepared based on the ZINC-15 database. Lipinski's rule of five, drug-likeness, and toxicity screening of the designed library were evaluated. Swiss model online server was used for modeling of GANAB target. Finally, docking-based screening against ADPKD targets was done by MOE 2019 software. The top 14 favorable druglike and non-toxic hits were selected for docking studies. Our results showed that compound-10 (ZINC 6073947) as a sesquiterpene coumarin had more negative binding interaction into the active site of PPARG, OXSR1, GANAB, AVPR2, and PC2 with docking scores of -8.22, -7.52, -6.98, -6.61 and -6.05 kcal/mol, respectively, in comparison to Curcumin, as a natural product that is now in phase 4 clinical trial in ADPKD disease, with an affinity of -8.03, -6.42, -6.82, -5.84 and -5.10 kcal/mol, respectively. Furthermore, seven sesquiterpene coumarins similar to compound 10 were generated and docked. Farnesiferol B (16), compared to compound-10, showed binding affinity of -8.16, -6.4, -7.46, -6.92, and -6.11 kcal/mol against the above targets, respectively. Molecular dynamics, which was done on the compound-10 and 16 (Farnesiferol B) in complex with PPARG, GANAB, and AVPR2, showed more negative binding free-energy than Pioglitazone, Miglitol, and Tolvaptan as FDA-approved drugs for each target, respectively.Communicated by Ramaswamy H. Sarma.

The emerging functions of intraflagellar transport 52 in ciliary transport and ciliopathies

Ciliary transport in eukaryotic cells is an intricate and conserved process involving the coordinated assembly and functioning of a multiprotein intraflagellar transport (IFT) complex. Among the various IFT proteins, intraflagellar transport 52 (IFT52) plays a crucial role in ciliary transport and is implicated in various ciliopathies. IFT52 is a core component of the IFT-B complex that facilitates movement of cargoes along the ciliary axoneme. Stable binding of the IFT-B1 and IFT-B2 subcomplexes by IFT52 in the IFT-B complex regulates recycling of ciliary components and maintenance of ciliary functions such as signal transduction and molecular movement. Mutations in the IFT52 gene can disrupt ciliary trafficking, resulting in dysfunctional cilia and affecting cellular processes in ciliopathies. Such ciliopathies caused by IFT52 mutations exhibit a wide range of clinical features, including skeletal developmental abnormalities, retinal degeneration, respiratory failure and neurological abnormalities in affected individuals. Therefore, IFT52 serves as a promising biomarker for the diagnosis of various ciliopathies, including short-rib thoracic dysplasia 16 with or without polydactyly. Here, we provide an overview of the IFT52-mediated molecular mechanisms underlying ciliary transport and describe the IFT52 mutations that cause different disorders associated with cilia dysfunction.

Congenital Hepatic Fibrosis as an Early Sign of Presentation of ADPKD

Autosomal dominant polycystic kidney disease (ADKPD) is the most frequent type of polycystic kidney disease. It is inherited through family members, with an incidence of approximately 1:400 to1:1000.Typically, individuals with ADKPD are identified between their fourth and fifth decade of life. ADKPD occurs as a results of mutation in one of the two genes, PDK1 and PDK2.Patients with PKD1 experience renal failure at an earlier onset than those with PKD2. We report on a 2 year-old-boy with hepatosplenomegaly and signs of portal hypertension. Both kidneys appeared normal until the age of 8, when multiple cysts developed, this being typical of ADKPD. Suspecting ADKPD, we performed whole exome sequencing, thereby confirming a mutation of c.6730 673del p.(Ser 2244Hisfs*17). The investigations of all family members found other individuals affected by ADKPD.

Proteomic Approaches and Potential Applications in Autosomal Dominant Polycystic Kidney Disease and Fabry Disease

Although rare, hereditary diseases, such as autosomal dominant polycystic kidney disease (ADPKD) and Fabry disease (FD) may significantly progress towards severe nephropathy. It is crucial to characterize it accurately, predict the course of the illness and estimate treatment effectiveness. A huge effort has been undertaken to find reliable biomarkers that might be useful for an early prevention of the disease progression and/or any invasive diagnostic procedures. The study of proteomics, or the small peptide composition of a sample, is a field of study under continuous development. Over the past years, several strategies have been created to study and define the proteome of samples from widely varying origins. However, urinary proteomics has become essential for discovering novel biomarkers in kidney disease. Here, the extracellular vesicles in human urine that contain cell-specific marker proteins from every segment of the nephron, offer a source of potentially valuable urinary biomarkers, and may play an essential role in kidney development and kidney disease. This review summarizes the relevant literature investigating the proteomic approaches and potential applications in the regular studies of ADPKD and FD.

Life-Threatening Retroperitoneal Hemorrhage Following Cyst Rupture in Autosomal Dominant Polycystic Kidney Disease (ADPKD): A Case Report

BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is the leading genetic cause of kidney failure worldwide. It is characterized by cyst formation and growth, kidney parenchymal destruction, and complications including cyst infection, nephrolithiasis, cyst rupture, and cyst hemorrhage. Cyst bleeding is typically a self-limited event. This case report describes a 60-year-old man with ADPKD admitted with retroperitoneal hemorrhage following renal cyst rupture requiring embolization of a bleeding left lumbar artery and use of tranexamic acid. CASE REPORT A 60-year-old man with ADPKD presented with altered mental status. Labs noted hemoglobin of 4.7 g/dL. Abdominal imaging revealed polycystic kidneys and large left retroperitoneal hematoma. Angiogram demonstrated active bleeding from left L3 lumbar artery which was embolized. He was admitted to intensive care unit for hemorrhagic shock requiring multiple blood transfusions. Hemoglobin continued to downtrend despite blood products with repeat imaging demonstrating expanding retroperitoneal bleed. He underwent repeat angiogram and though there was no active bleeding, prophylactic embolization of left L1, L3, L4 lumbar and left renal capsular arteries were performed. Hemoglobin stabilized for next 3 days but continued to downtrend subsequently. Oral tranexamic acid was trialed with stabilization of the hemoglobin. CONCLUSIONS Life-threatening retroperitoneal hemorrhage following cyst rupture in the absence of major trauma or use of anti-coagulants, is a rare complication in ADPKD. Treatment involves resuscitation with blood products, management of shock, and interventional radiology-guided embolization. Tranexamic acid may be considered when the above measures fail. Nephrectomy may be indicated for refractory bleeding. This report highlights the diagnosis and management of massive cyst bleeding in ADPKD.

The inhibition of MDM2 slows cell proliferation and activates apoptosis in ADPKD cell lines

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is characterised by progressive cysts formation and renal enlargement that in most of cases leads to end stage of renal disease (ESRD). This pathology is caused by mutations of either PKD1 or PKD2 genes that encode for polycystin-1 (PC1) and polycystin-2 (PC2), respectively. These proteins function as receptor-channel complex able to regulate calcium homeostasis. PKD1/2 loss of function impairs different signalling pathways including cAMP and mTOR that are considered therapeutic targets for this disease. In fact, Tolvaptan, a vasopressin-2 antagonist that reduces cAMP levels, is the only drug approved for ADPKD treatment. Nevertheless, some ADPKD patients developed side effects in response to Tolvaptan including liver damage. Conversely, mTOR inhibitors that induced disease regression in ADPKD animal models failed the clinical trials.

RESULTS

Here, we show that the inhibition of mTOR causes the activation of autophagy in ADPKD cells that could reduce therapy effectiveness by drug degradation through the autophagic vesicles. Consistently, the combined treatment with rapamycin and chloroquine, an autophagy inhibitor, potentiates the decrease of cell proliferation induced by rapamycin. To overcome the dangerous activation of autophagy by mTOR inhibition, we targeted MDM2 (a downstream effector of mTOR signalling) that is involved in TP53 degradation by using RG7112, a small-molecule MDM2 inhibitor used for the treatment of haematologic malignancies. The inhibition of MDM2 by RG7112 prevents TP53 degradation and increases p21 expression leading to the decrease of cell proliferation and the activation of apoptosis.

CONCLUSION

The targeting of MDM2 by RG7112 might represent a new therapeutic option for the treatment of ADPKD.

The lonidamine derivative H2-gamendazole reduces cyst formation in polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a debilitating renal neoplastic disorder with limited treatment options. It is characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. We tested the effectiveness of the indazole carboxylic acid H2-gamendazole (H2-GMZ), a derivative of lonidamine, to inhibit these processes using in vitro and in vivo models of ADPKD. H2-GMZ was effective in rapidly blocking forskolin-induced, Cl--mediated short-circuit currents in human ADPKD cells, and it significantly inhibited both cAMP- and epidermal growth factor-induced proliferation of ADPKD cells. Western blot analysis of H2-GMZ-treated ADPKD cells showed decreased phosphorylated ERK and decreased hyperphosphorylated retinoblastoma levels. H2-GMZ treatment also decreased ErbB2, Akt, and cyclin-dependent kinase 4, consistent with inhibition of heat shock protein 90, and it decreased levels of the cystic fibrosis transmembrane conductance regulator Cl- channel protein. H2-GMZ-treated ADPKD cultures contained a higher proportion of smaller cells with fewer and smaller lamellipodia and decreased cytoplasmic actin staining, and they were unable to accomplish wound closure even at low H2-GMZ concentrations, consistent with an alteration in the actin cytoskeleton and decreased cell motility. Experiments using mouse metanephric organ cultures showed that H2-GMZ inhibited cAMP-stimulated cyst growth and enlargement. In vivo, H2-GMZ was effective in slowing postnatal cyst formation and kidney enlargement in the Pkd1flox/flox: Pkhd1-Cre mouse model. Thus, H2-GMZ treatment decreases Cl- secretion, cell proliferation, cell motility, and cyst growth. These properties, along with its reported low toxicity, suggest that H2-GMZ might be an attractive candidate for treatment of ADPKD.NEW & NOTEWORTHY Autosomal dominant polycystic kidney disease (ADPKD) is a renal neoplastic disorder characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. This study shows that the lonidamine derivative H2-GMZ inhibits Cl- secretion, cell proliferation, and cyst growth, suggesting that it might have therapeutic value for the treatment of ADPKD.

Targeted Next Generation Sequencing Revealed Novel Variants in the PKD1 and PKD2 Genes of Iranian Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD), one of the common inherited disorders in humans, is characterized by the development and enlargement of renal cysts, often leading to end-stage renal disease (ESRD). In this study, Iranian ADPKD families were subjected to high-throughput DNA sequencing to find potential causative variants facilitating the way toward risk assessment and targeted therapy.

METHODS

Our protocol was based on the targeted next generation sequencing (NGS) panel previously developed in our center comprising 12 genes involved in PKD. This panel has been applied to investigate the genetic causes of 32 patients with a clinical suspicion of ADPKD.

RESULTS

We identified a total of 31 variants for 32 individuals, two of which were each detected in two individuals. Twenty-seven out of 31 detected variants were interpreted as pathogenic/likely pathogenic and the remaining 4 of uncertain significance with a molecular diagnostic success rate of 87.5%. Among these variants, 25 PKD1/2 pathogenic/likely pathogenic variants were detected in 32 index patients (78.1%), and variants of uncertain significance in four individuals (12.5% in PKD1/2). The majority of variants was identified in PKD1 (74.2%). Autosomal recessive PKD was identified in one patient, indicating the similarities between recessive and dominant PKD. In concordance with earlier studies, this biallelic PKD1 variant, p.Arg3277Cys, leads to rapidly progressive and severe disease with very early-onset ADPKD.

CONCLUSION

Our findings suggest that targeted gene panel sequencing is expected to be the method of choice to improve diagnostic and prognostic accuracy in PKD patients with heterogeneity in genetic background.

Prediction of cardiovascular outcome by estimated glomerular filtration rate among high-risk patients: a Thai nationwide cohort study

BACKGROUND

Decline of estimated glomerular filtration rate (eGFR) is associated with increased cardiovascular (CV) morbidity and mortality, but the predictive value of different eGFR on CV outcomes is limited in Southeast Asian populations.

AIMS

We aimed to stratify CV outcomes according to renal function among Thai patients with high atherosclerosis risk.

METHODS

We performed a secondary analysis in a 5-year national cohort entitled "CORE-Thailand study." Subjects were classified in 6 groups according to baseline kidney function: group I, eGFR ≥ 90; group II, eGFR 60-89; group IIIa, eGFR 45-59; group IIIb, eGFR 30-44; group IV, eGFR 15-29; group V, eGFR < 15 ml/min/1.73 m² or receiving renal replacement therapy. The primary outcome was 4-point major adverse cardiovascular events (MACE). Secondary outcomes included all-cause mortality, CV mortality, hospitalization for heart failure, nonfatal myocardial infarction, and nonfatal stroke.

RESULTS

A total of 6376 subjects (3467 men and 2909 women) were categorized in 6 groups. After adjusting covariates in the Cox proportional hazards model, compared to group I, subjects in groups II-V had a 1.65-fold, 2.17-fold, 2.67-fold, 4.24-fold, and 4.87-fold risk for 4-point MACE, respectively, with statistical significance at P < 0.05 in all groups. Kaplan-Meier analysis illustrated stepwise lower survivals from 4-point MACE following the groups with lower baseline eGFR (log-rank test with P < 0.001). All secondary outcomes showed similar trends as the primary outcome, except nonfatal stroke.

CONCLUSION

Lower baseline kidney function was independently associated with increased risk of CV events and all-cause mortality in Thai populations at high CV risk.

Restoration of atypical protein kinase C ζ function in autosomal dominant polycystic kidney disease ameliorates disease progression

Autosomal dominant polycystic kidney disease (ADPKD) affects more than 500,000 individuals in the United States alone. In most cases, ADPKD is caused by a loss-of-function mutation in the PKD1 gene, which encodes polycystin-1 (PC1). Previous studies reported that PC1 interacts with atypical protein kinase C (aPKC). Here we show that PC1 binds to the ζ isoform of aPKC (PKCζ) and identify two PKCζ phosphorylation sites on PC1's C-terminal tail. PKCζ expression is down-regulated in patients with ADPKD and orthologous and nonorthologous PKD mouse models. We find that the US Food and Drug Administration-approved drug FTY720 restores PKCζ expression in in vitro and in vivo models of polycystic kidney disease (PKD) and this correlates with ameliorated disease progression in multiple PKD mouse models. Importantly, we show that FTY720 treatment is less effective in PKCζ null versions of these PKD mouse models, elucidating a PKCζ-specific mechanism of action that includes inhibiting STAT3 activity and cyst-lining cell proliferation. Taken together, our results reveal that PKCζ down-regulation is a hallmark of PKD and that its stabilization by FTY720 may represent a therapeutic approach to the treat the disease.

Establishment and Characterization of MUi027-A: A Novel Patient-Derived Cell Line of Polycystic Kidney Disease with PKD1 Mutation

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most prevalent genetic diseases affecting the kidneys. A genetically specific mutation model is required to comprehend its pathophysiology and to develop a drug treatment. In this study, we successfully developed human induced pluripotent stem cells (hiPSCs) named MUi027-A from skin fibroblasts of a patient diagnosed with ADPKD and carrying the PKD1 frameshift mutation (c.7946_7947delCT). MUi027-A cells showed the same genetic fingerprints as the parental cells, including the presence of the PKD1 mutation. MUi027-A hiPSCs displayed embryonic stem cell-like characteristics with the capability of differentiating into the three germ layers. Upon directed differentiation, MUi027-A hiPSCs could be differentiated into tubular organoids with the expression of renal cell markers. Furthermore, we compared the efficiency of cyst formation in two human iPSC lines with different PKD1 mutations. When cyst formation was induced by either forskolin or blebbistatin, MUi027-A hiPSC-derived kidney organoids displayed higher frequencies of cyst formation when compared to organoids generated from an iPSC cell line with non-truncating PKD1 mutation genotype (c.5878C > T), suggesting the presence of physiological differences in the mechanism of cyst formation between different PKD1 mutants. Overall, we generated and characterized a novel human iPSC line with a specific PKD mutation and demonstrated its potential as a disease model to study the pathophysiology of genetic determinants in the development of ADPKD disease.

Recurrent thromboses and major vessel compressions in autosomal dominant polycystic kidney disease

A 41-year-old man with autosomal dominant polycystic kidney disease (ADPKD), who had multiple previous unprovoked thrombotic events and without a known coagulopathic disorder, presented with symptomatic extensive thrombus distal to the compression site of the left common iliac vein by a dominant cyst in the left inferior renal pole. This was managed with inferior vena cava filter insertion, left nephrectomy and warfarinization. Later, there was inferior vena cava compression by the right polycystic kidney, leading to elective right nephrectomy. Post-renal transplantation, he had further episodes of partial dialysis access stenosis and extensive thromboses in the left deep and right superficial venous systems of the lower limbs despite absence of extrinsic compression. This represents the first report of recurrent mass effect and thromboembolic events in ADPKD, both before and after nephrectomy and anticoagulation. The potential increased thromboembolic risks among patients with ADPKD warrant further investigation.

Obacunone Retards Renal Cyst Development in Autosomal Dominant Polycystic Kidney Disease by Activating NRF2

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disease characterized by progressive enlargement of fluid-filled cysts derived from renal tubular epithelial cells, which has become the fourth leading cause of end-stage renal diseases. Currently, treatment options for ADPKD remain limited. The purpose of this study was to discover an effective therapeutic drug for ADPKD. With virtual screening, Madin-Darby canine kidney (MDCK) cyst model, embryonic kidney cyst model and kidney-specific Pkd1 knockout mouse (PKD) model, we identified obacunone as a candidate compound for ADPKD drug discovery from a natural antioxidant compound library. In vitro experiments showed that obacunone significantly inhibited cyst formation and expansion of MDCK cysts and embryonic kidney cysts in a dose-dependent manner. In vivo, obacunone treatment significantly reduced the renal cyst development in PKD mice. Western blot and morphological analysis revealed that obacunone served as a NRF2 activator in ADPKD, which suppressed lipid peroxidation by up-regulating GPX4 and finally restrained excessive cell proliferation by down-regulating mTOR and MAPK signaling pathways. Experimental data demonstrated obacunone as an effective renal cyst inhibitor for ADPKD, indicating that obacunone might be developed into a therapeutic drug for ADPKD treatment.

Germline Mutations for Kidney Volume in ADPKD

Introduction

Valid prediction models or predictors of disease progression in children and young patients with autosomal dominant polycystic kidney disease (ADPKD) are lacking. Although total kidney volume (TKV) and Mayo imaging classification are generally used to predict disease progression in patients with ADPKD, it remains unclear whether germline mutation types are associated with these factors. We therefore investigated the association between mutation type and TKV and Mayo imaging classification among patients with ADPKD.

Methods

A total of 129 patients with ADPKD who underwent genetic analyses were enrolled in the study. The associations between the severity of PKD (TKV ≥ 1000 ml and Mayo classes 1C–1E) and the PKD1 mutation types (nonsense mutation, frameshift or splicing mutation, and substitution) were evaluated.

Results

Among the mutation types, only PKD1 splicing/frameshift mutation had significant associations with TKV ≥ 1000 ml in sex-adjusted and multivariable logistic analyses. Similarly, only the PKD1 splicing/frameshift mutation was significantly associated with Mayo 1C–1E in sex-adjusted and multivariable logistic analyses. PKD1 nonsense mutation, PKD1 substitution, or PKD1 mutation position had no significant association with TKV ≥ 1000 ml or Mayo 1C–1E.

Conclusion

Kidney cyst severity differs according to the mutation types in PKD1. Patients with PKD1 splicing mutations or PKD1 frameshift mutations are associated with TKV ≥ 1000 ml or Mayo 1C–1E. Detailed assessment of mutation types may be useful for predicting renal prognosis in patients with ADPKD and may especially contribute to the care of a high-risk group of children with ADPKD.

The cellular pathways and potential therapeutics of Polycystic Kidney Disease

Polycystic Kidney Disease (PKD) refers to a group of disorders, driven by the formation of cysts in renal tubular cells and is currently one of the leading causes of end-stage renal disease. The range of symptoms observed in PKD is due to mutations in cilia-localising genes, resulting in changes in cellular signalling. As such, compounds that are currently in preclinical and clinical trials target some of these signalling pathways that are dysregulated in PKD. In this review, we highlight these pathways including cAMP, EGF and AMPK signalling and drugs that target them and may show promise in lessening the disease burden of PKD patients. At present, tolvaptan is the only approved therapy for ADPKD, however, it carries several adverse side effects whilst comparatively, no pharmacological drug is approved for ARPKD treatment. Aside from this, drugs that have been the subject of multiple clinical trials such as metformin, which targets AMPK signalling and somatostatins, which target cAMP signalling have shown great promise in reducing cyst formation and cellular proliferation. This review also discusses other potential and novel targets that can be used for future interventions, such as β-catenin and TAZ, where research has shown that a reduction in the overexpression of these signalling components results in amelioration of disease phenotype. Thus, it becomes apparent that well-designed preclinical investigations and future clinical trials into these pathways and other potential signalling targets are crucial in bettering disease prognosis for PKD patients and could lead to personalised therapy approaches.