Ghanem, Ahmad

Background: Total kidney volume (TKV), a prognostic biomarker in ADPKD, is used to stratify high risk individuals. eGFR measures may carry significant error in ADPKD compared to measured GFR(mGFR). This retrospective study investigates the association between height adjusted TKV (htTKV) and eGFR derived from race-free CKD-EPI equations utilizing creatinine and cystatin C. Methods: eGFR was calculated using 3 race-free CKD-EPI formulas: creatinine-based (CKD-EPI creatinine), cystatin C (CKD-EPI cys), and creatinine-cystatin C (CKD-EPI creatinine-cystatin C) equations on 697 Mayo Clinic ADPKD patients. Correlations between eGFR and TKV measures were estimated and stratified by MIC class risk groups and CKD. Linear regression models were computed to predict ln(htTKV) from the 3 eGFR data sets. The eGFR measures were compared to iothalamate-based mGFR in a subset of patients (n=50). Results: A correlation between eGFR measures and htTKV (Pearson correlation r of -0.53 to -0.54), varied by MIC stratification. Pearson correlation was -0.47 to -0.48 for MIC 1A and 1B, -0.67 to -0.71 for MIC 1C, and -0.67 to -0.68 for MIC 1D and 1E. All equations were significantly associated with htTKV levels, with similar adjusted beta values (95% CI) of -0.15 (-0.17 to -0.13), -0.14 (-0.16 to -0.12), -0.15 (-0.16 to -0.13), for CKD-EPI creatinine, CKD-EPI cystatin C, and CKD-EPI creatinine-cystatin C, respectively. Compared to mGFR, the CKD-EPI creatinine-cystatin C equation was the least biased (mean -0.86 (95% CI: -3.09 to 1.37)) versus CKD-EPI creatinine (2.31 (-0.73 to 5.34)) or CKD-EPI cystatin C (-3.54 (-5.86 to -1.21)), and most precise, with 1-P30 of 16% (95% CI 7.2% to 29.1%), compared to 18% (8.6% to 31.4%) for CKD-EPI creatinine, or 20% (10.0% to 33.7%) for CKD-EPI cystatin C. Conclusion: A moderate correlation between eGFR and htTKV associated with MIC stratification. Associations between htTKV and all 3 CKD-EPI equations were similar. CKDEPIcrcys tended to be the least biased and most precise equation when compared to mGFR and may be a reasonable alternative.

Renal water reabsorption is classically regulated by vasopressin V2 receptor (V2R) signaling through cyclic AMP and protein kinase A, driving apical accumulation of aquaporin-2 (AQP2). However, collecting duct water handling is also modulated by vasopressin-independent mechanisms. Here, we examined intracellular soluble urate as a vasopressin-independent regulator of AQP2 trafficking. Intracellular urate accumulation in collecting duct cells was mediated by enhanced apical urate uptake via GLUT9b and reduced apical urate efflux through ABCG2, triggering phosphodiesterase-4 activation, reduced cAMP, and downstream AMP-activated protein kinase (AMPK) activation. The resulting AQP2 accumulation at the apical membrane was independent of V2R signaling, required ongoing endocytosis, and was associated with features of postendocytic apical trafficking of internalized AQP2. In vivo ABCG2 inhibition with probenecid increased apical AQP2 abundance and markedly attenuated tolvaptan-induced polyuria in both wild-type and Pkd1 RC/RC autosomal dominant polycystic kidney disease (ADPKD) mice in a uricase-independent manner while preserving tolvaptan’s ADPKD-modifying efficacy. In a phase II trial with tolvaptan-treated patients with ADPKD, probenecid reduced urine volume and nocturia frequency. Together, these findings support a vasopressin-independent urate/AMPK/AQP2 pathway that regulates renal water handling and, in a preclinical ADPKD model, can uncouple cyst growth attenuation from the dose-limiting aquaretic effects of V2R antagonism.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder and a leading cause of kidney failure worldwide. Disease progression is driven by cyst expansion, tubular injury, and maladaptive metabolic and hemodynamic changes. Tolvaptan remains the only US Food and Drug Administration–approved disease-modifying therapy, however its tolerability and safety profile highlight the need for additional strategies. Sodium-glucose cotransporter 2 inhibitors (SGLT2is), initially developed for glycemic control, have demonstrated robust kidney-protective and cardioprotective effects across diverse patient populations, including those without diabetes. By lowering intraglomerular pressure, metabolic reprogramming, and attenuating hypoxic microenvironment and inflammation, SGLT2is target mechanisms that are relevant to ADPKD. However, concerns that SGLT2i may provoke osmotic diuresis and activate vasopressin led to systematic exclusion of patients with ADPKD from pivotal outcome trials. The 2025 Kidney Disease Improving Global Outcomes ADPKD guidelines explicitly advise against the use of SGLT2i for slowing kidney function decline in ADPKD. In this review, we examine mechanistic intersections between SGLT2i and ADPKD pathophysiology, summarize available preclinical and early clinical data, and discuss ongoing large trials designed to address safety and efficacy of SGLT2i in patients with ADPKD. We also highlight the importance of genetic heterogeneity, as most ongoing trials are enriched for rapid progressors carrying PKD1 or PKD2 pathogenic variants, while other genotypes such as DNAJB11 , ALG8 , and ALG9 , often associated with greater interstitial fibrosis, are underrepresented. Substratification of patients by genotype, risk of progression, and comorbidities will be essential to guide precision application of SGLT2i. Whether SGLT2i can ultimately be positioned as an adjunctive or standalone therapy for ADPKD remains unresolved.

Key Points This study demonstrates that peritoneal dialysis is a safe and feasible option for patients with autosomal dominant polycystic kidney disease, even with high cystic organ volumes. Larger organ volumes, including height-adjusted cumulative kidney and liver volume, were not associated with increased peritoneal dialysis–related complications. Background Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent genetic kidney disorder and the fourth leading cause of kidney failure. Peritoneal dialysis (PD), preferred for its home-based convenience and cost-effectiveness, is often underutilized in ADPKD because of concerns over enlarged kidneys and heightened risk of complications. Methods This retrospective cohort study used data from the Mayo Clinic Polycystic Kidney Disease Database to evaluate individuals with ADPKD undergoing PD. We analyzed demographics, clinical parameters, and PD-related parameters. Complications were correlated with kidney and liver volumes derived from pre-kidney failure imaging. Results A total of 155 individuals with ADPKD on PD were included, of whom 45.1% were male. The mean age at PD initiation was 54.3±12.8 years, and the mean body mass index was 28.0±7.0 kg/m 2 . The median duration of PD was 24.3 months (interquartile range [IQR], 10.7–43.1), with 21.9% transitioning to hemodialysis. The most common complications were abdominal hernias (30.3%) and peritonitis (23.9%), with a peritonitis rate of 0.11 episodes per patient-year. Imaging analyses performed on a subset of 50 patients showed a median height-adjusted total kidney liver volume of 2731.9 ml/m (IQR, 2102.5–3131.1) and a median height-adjusted total kidney volume of 1303.5 ml/m (IQR, 733.1–1829.4). Kaplan–Meier analysis demonstrated no differences in complications rates on the basis of height-adjusted total kidney liver volume or height-adjusted total kidney volume (above versus below median values) or body mass index categories. Multivariate Cox regression analysis revealed that higher height-adjusted cumulative organ volume was associated with a lower risk of PD-related complications (hazard ratio=0.56, P = 0.026). Conclusions PD is a safe and feasible treatment option for patients with ADPKD, with no increased risk of PD-related complications associated with larger height-adjusted cumulative organ volumes. Infectious complication rates in this cohort were within International Society of Peritoneal Dialysis guideline thresholds, further supporting the safety of PD in this population.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disorder. It is primarily caused by pathogenic variants in the PKD1 or PKD2 genes. This leads to the development of numerous kidney cysts, which can result in kidney enlargement and progression to kidney failure. Pain is a common symptom in ADPKD and can negatively affect quality of life (QOL). This pain is often due to the continuous growth of kidney and liver cysts or associated cystic complications. We present a case of a 29-year-old woman with ADPKD who experienced chronic, refractory right-sided flank pain that significantly affected her QOL. Her pain persisted despite taking daily multimodal analgesics and undergoing multiple invasive interventions. She had an unusual asymmetric disease with the right kidney accounting for only 24% of her kidney function. After exhausting all other pain control strategies, she underwent right nephrectomy and partial hepatectomy, which led to substantial improvement in pain and QOL. This review describes the causes, manifestations, and management strategies for abdominal and/or flank pain in ADPKD, including a practical stepwise algorithm to guide clinicians in managing pain and improve QOL of patients with ADPKD. Pain in ADPKD can either be acute or chronic and can lead to significant physical and psychologic distress. Effective pain management in ADPKD requires a multidisciplinary approach, incorporating both nonpharmacologic and pharmacologic interventions such as gabapentin or tolvaptan in select cases. Interventions considered in ADPKD pain control include cyst aspiration with sclerotherapy, celiac plexus blockade, spinal cord stimulation, renal denervation, or nephrectomy.