Autosomal Dominant Polycystic Kidney Disease

Prevalence of Spinal Meningeal Diverticula in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND PURPOSE

Patients with autosomal dominant polycystic kidney disease (ADPKD) develop cysts in the kidneys, liver, spleen, pancreas, prostate, and arachnoid spaces. In addition, spinal meningeal diverticula have been reported. To determine whether spinal meningeal diverticula are associated with ADPKD, we compared their prevalence in subjects with ADPKD with a control cohort without ADPKD.

MATERIALS AND METHODS

Subjects with ADPKD and age- and sex-matched controls without ADPKD undergoing abdominal MRI from the midthorax to the pelvis from 2003 to 2023 were retrospectively evaluated for spinal meningeal diverticula by 4 blinded observers. The prevalence of spinal meningeal diverticula in ADPKD was compared with that in control subjects, using t tests and correlated with clinical and laboratory data and MR imaging features, including cyst volumes and cyst counts.

RESULTS

Identification of spinal meningeal diverticula in ADPKD (n = 285, median age, 47; interquartile range [IQR], 37-56 years; 54% female) and control (n = 285, median age, 47; IQR, 37-57 years; 54% female) subjects had high interobserver agreement (pairwise Cohen κ = 0.74). Spinal meningeal diverticula were observed in 145 of 285 (51%) subjects with ADPKD compared with 66 of 285 (23%) control subjects without ADPKD (P < .001). Spinal meningeal diverticula in ADPKD were more prevalent in women (98 of 153 [64%]) than men (47 of 132 [36%], P < .001). The mean number of spinal meningeal diverticula per affected subject with ADPKD was 3.6 ± 2.9 compared with 2.4 ± 1.9 in controls with cysts (P < .001). The median volume (IQR, 25%-75%) of spinal meningeal diverticula was 400 (IQR, 210-740) mm3 in those with ADPKD compared with 250 (IQR, 180-440) mm3 in controls (P < .001). The mean spinal meningeal diverticulum diameter was greater in the sacrum (7.3 [SD, 4.1] mm) compared with thoracic (5.4 [SD, 1.8] mm) and lumbar spine (5.8 [SD, 2.0] mm), (P < .001), suggesting that hydrostatic pressure contributed to enlargement.

CONCLUSIONS

ADPKD has a high prevalence of spinal meningeal diverticula, particularly in women.

Long-term effectiveness and safety of tolvaptan in autosomal dominant polycystic kidney disease

BACKGROUND AND OBJECTIVES

Evidence on the long-term use of tolvaptan in autosomal dominant polycystic kidney disease (ADPKD) is limited. The aim was to evaluate the tolvaptan effectiveness and safety in real clinical setting.

MATERIAL AND METHODS

A single-center observational study (2016-2022) involving ADPKD patients treated with tolvaptan was conducted. Annual change in serum creatinine (sCr) and estimated glomerular filtration rate (eGFR) before and after treatment initiation were evaluated. Change in total kidney volume (TKV), blood pressure (BP) and urinary albuminuria at 12, 24 and 36 months after initiation were also determined. Adverse events (AEs) according to the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 were analyzed.

RESULTS

A total of 22 patients were included. No significant differences pre- vs post tolvaptan treatment in annual rate of change in eGFR (-3.52ml/min/1.73m2 [-4.98%] vs -3.98ml/min/1.73m2 [-8.48%], p=0.121) and sCr (+0.06mg/dL [4.22%] vs +0.15mg/dL [7.77%], p=0.429) were observed. Tolvaptan improved urinary osmolality at 12 (p=0.019) and 24 months (p=0.008), but not at 36 months (p=0.11). There were no changes in TKV, BP control and urinary albuminuria at 12, 24 or 36 months. A worse response was shown in patients with rapid kidney function decline (p=0.042). A 36.4% of the patients developed grade III/IV AEs. A 22.7% discontinued treatment due to unacceptable toxicity.

CONCLUSIONS

This study shows a modest benefit of tolvaptan in ADPKD patients, as well as safety concerns.

The screening, diagnosis, and management of patients with autosomal dominant polycystic kidney disease: A national consensus statement from Taiwan

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of end-stage kidney disease (ESKD) worldwide. Guidelines for the diagnosis and management of ADPKD in Taiwan remains unavailable. In this consensus statement, we summarize updated information on clinical features of international and domestic patients with ADPKD, followed by suggestions for optimal diagnosis and care in Taiwan. Specifically, counselling for at-risk minors and reproductive issues can be important, including ethical dilemmas surrounding prenatal diagnosis and pre-implantation genetic diagnosis. Studies reveal that ADPKD typically remains asymptomatic until the fourth decade of life, with symptoms resulting from cystic expansion with visceral compression, or rupture. The diagnosis can be made based on a detailed family history, followed by imaging studies (ultrasound, computed tomography, or magnetic resonance imaging). Genetic testing is reserved for atypical cases mostly. Common tools for prognosis prediction include total kidney volume, Mayo classification and PROPKD/genetic score. Screening and management of complications such as hypertension, proteinuria, urological infections, intracranial aneurysms, are also crucial for improving outcome. We suggest that the optimal management strategies of patients with ADPKD include general medical care, dietary recommendations and ADPKD-specific treatments. Key points include rigorous blood pressure control, dietary sodium restriction and Tolvaptan use, whereas the evidence for somatostatin analogues and mammalian target of rapamycin (mTOR) inhibitors remains limited. In summary, we outline an individualized care plan emphasizing careful monitoring of disease progression and highlight the need for shared decision-making among these patients.

Prevalence of pericardial effusion in autosomal dominant polycystic kidney disease

Background

Autosomal dominant polycystic kidney disease (ADPKD) has numerous extrarenal manifestations. Pericardial effusion (PE) may be an underrecognized complication with a reported prevalence of up to 35%. Our study is the first to systematically evaluate the prevalence of PE and associated risk factors in an ADPKD cohort outside the USA.

Methods

Clinically stable ADPKD patients from a specialized outpatient clinic were evaluated retrospectively. Magnetic resonance tomography and computed tomography scans were analysed regarding the presence of PE (≥4 mm). Imaging results were linked to clinical characteristics.

Results

Of 286 ADPKD patients, 208 had computed tomography or magnetic resonance imaging suitable for evaluation of PE. In this group we detected PE in 17 patients (8.2%). The overall prevalence of PE was 6.3%, with more females being affected (prevalence of PE was 7.8% in females and 3.8% in males). The PE mean size was 6.8 ± 3.3 mm. The prevalence of autoimmune diseases was higher in the patients with PE (11.8% versus 2.1%, P = .022), while the presence and size of PE was not associated with signs of rapid progressive disease, ADPKD genotype, patient age, body mass index and other clinical parameters. Exploratory investigation of individual characteristics of PE patients by regression tree analysis suggested renal functional impairment, sex and proteinuria as candidate variables.

Conclusions

PE prevalence in our cohort was lower than previously reported and showed a clear female preponderance. Our data suggest that patients with PEs >10 mm deserve further attention, as they may have additional non-ADPKD-related pathologies.

The genetic spectrum of polycystic kidney disease in children

OBJECTIVE

Autosomal dominant polycystic kidney disease is an inherited kidney disorder with mutations in polycystin-1 or polycystin-2. Autosomal recessive polycystic kidney disease is a severe form of polycystic kidney disease that is characterized by enlarged kidneys and congenital hepatic fibrosis. Mutations at PKHD1 are responsible for all typical forms of autosomal recessive polycystic kidney disease.

METHODS

We evaluated the children diagnosed with polycystic kidney disease between October 2020 and May 2022. The diagnosis was established by family history, ultrasound findings, and/or genetic analysis. The demographic, clinical, and laboratory findings were evaluated retrospectively.

RESULTS

There were 28 children (male/female: 11:17) evaluated in this study. Genetic analysis was performed in all patients (polycystin-1 variants in 13, polycystin-2 variants in 7, and no variants in 8 patients). A total of 18 variants in polycystin-1 and polycystin-2 were identified and 9 (50%) of them were not reported before. A total of eight novel variants were identified as definite pathogenic or likely pathogenic mutations. There was no variant detected in the PKDH1 gene.

CONCLUSION

Our results highlighted molecular features of Turkish children with polycystic kidney disease and demonstrated novel variations that can be utilized in clinical diagnosis and prognosis.

The effect of autosomal dominant polycystic kidney disease on mucociliary clearance

PURPOSE

Autosomal dominant polycystic kidney disease (ADPKD) is a renal disease with genetic transmisson. Mutations in the PKD1 and PKD2 genes, which encode integral membrane proteins of the cilia of primary renal tubule epithelial cells, are seen in ADPKD. The aim of this study was to evaluate the sinonasal epithelium, which is epithelium with cilia, by measuring the nasal mucociliary clearance time, and to investigate the effect of ADPKD on nasal mucociliary clearance.

METHODS

The study included 34 patients, selected from patients followed up in the Nephrology Clinic, and 34 age and gender-matched control group subjects. The nasal mucociliary clearance time (NMCT) was measured with the saccharin test.

RESULTS

The mean age of the study subjects was 47.15 ± 14.16 years in the patient group and 47.65 ± 13.85 years in the control group. The eGFR rate was determined as mean 72.06 ± 34.26 mL/min in the patient group and 99.79 ± 17.22 mL/min in the control group (p < 0.001). The NMCT was determined to be statistically significantly longer in the patient group (903.6 ± 487.8 s) than in the control group (580 ± 259 s) (p = 0.006).

CONCLUSIONS

The study results showed that the NMCT was statistically significantly longer in patients with ADPKD compared to the control group, but in the linear regression analysis results, no correlation was determined between eGFR and NMCT.

Considerations for genetic testing in individuals with autosomal dominant polycystic kidney disease

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic, irreversible, genetic condition caused by mutations in the PKD1 and PKD2 genes, and the most common form of inherited kidney disease in the United States, affecting more than 600,000 individuals. Because the condition is autosomal dominant, there is a 50% chance that each child of an affected adult will also have the pathogenic genetic mutation. PKD1 mutation accounts for approximately 85% of ADPKD cases and is characterized by an earlier onset of disease with more rapid progression, whereas PKD2 mutation accounts for the remaining 15% of cases and is characterized by a less severe and less rapid disease course. Genetic testing is not consistently used in the management of individuals with ADPKD, although it can provide invaluable information regarding disease progression and prognosis. Genetic data are necessary to effectively communicate disease progression with patients, use current prognostic calculators, and play a role in family planning. Increasing clinician knowledge in primary care and nephrology providers will contribute to improved care for individuals affected by ADPKD.

Identification of osteopontin as a urinary biomarker for autosomal dominant polycystic kidney disease progression

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD), one of the most common human monogenic diseases, is characterized by the presence of numerous fluid-filled renal cysts and is a leading cause of end-stage renal disease (ESRD). Urinary biomarkers may be useful for predicting the variable course of ADPKD progression from cyst growth to ESRD.

METHODS

To identify candidate urinary biomarkers of ADPKD progression, we used CRISPR/Cas9 genome editing to generate porcine fibroblasts with mono- and biallelic ADPKD gene knockout (PKD2+/- and PKD2-/-, respectively). We then performed RNA-sequencing analysis on these cells.

RESULTS

Levels of osteopontin (OPN), which is expressed by renal epithelial tubular cells and excreted into urine, were reduced in PKD2-/- cells but not in PKD2+/- cells. OPN levels were also reduced in the renal cyst cells of ADPKD patients. Next, we investigated whether OPN excretion was decreased in patients with ADPKD via enzyme-linked immunosorbent assay. OPN levels excreted into renal cyst cell culture media and urine from ADPKD patients were decreased. To investigate whether OPN can predict the rate of ADPKD progression, we compared urinary excretion of OPN in ADPKD patients with slow progression and those with rapid progression. Those with rapid progression had an estimated glomerular filtration rate of >60 mL/min/1.73 m2 . Urinary OPN excretion levels were lower in rapid progressors than in slow progressors.

CONCLUSION

These findings suggest that OPN is a useful urinary biomarker for predicting ADPKD progression.

Pericardial Effusion on MRI in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) has been associated with cardiac abnormalities including mitral valve prolapse and aneurysmal dilatation of the aortic root. Herein, we investigated the potential association of pericardial effusion with ADPKD. Subjects with ADPKD (n = 117) and control subjects without ADPKD matched for age, gender and renal function (n = 117) undergoing MRI including ECG-gated cine MRI of the aorta and heart were evaluated for pericardial effusion independently by three observers measuring the maximum pericardial effusion thickness in diastole using electronic calipers. Pericardial effusion thickness was larger in ADPKD subjects compared to matched controls (Mann-Whitney p = 0.001) with pericardial effusion thickness >5 mm observed in 24 of 117 (21%) ADPKD subjects compared to 4 of 117 (3%) controls (p = 0.00006). Pericardial effusion thickness in ADPKD was associated with female gender patients (1.2 mm greater than in males, p = 0.03) and pleural effusion thickness (p < 0.001) in multivariate analyses. No subjects exhibited symptoms related to pericardial effusion or required pericardiocentesis. In conclusion, pericardial effusion appears to be more prevalent in ADPKD compared to controls. Although in this retrospective cross-sectional study we did not identify clinical significance, future investigations of pericardial effusion in ADPKD subjects may help to more fully understand its role in this disease.

Roles of telomeres and telomerase in age‑related renal diseases (Review)

Age‑related renal diseases, which account for various progressive renal disorders associated with cellular and organismal senescence, are becoming a substantial public health burden. However, their aetiologies are complicated and their pathogeneses remain poorly understood. Telomeres and telomerase are known to be essential for maintaining the integrity and stability of eukaryotic genomes and serve crucial roles in numerous related signalling pathways that activate renal functions, such as repair and regeneration. Previous studies have reported that telomere dysfunction served a role in various types of age‑related kidney disease through various different molecular pathways. The present review aimed to summarise the current knowledge of the association between telomeres and ageing‑related kidney diseases and explored the contribution of dysfunctional telomeres to these diseases. The findings may help to provide novel strategies for treating patients with renal disease.