Estimating risk of rapid disease progression in pediatric patients with autosomal dominant polycystic kidney disease: a randomized trial of tolvaptan

BACKGROUND

Tolvaptan preserves kidney function in adults with autosomal dominant polycystic kidney disease (ADPKD) at elevated risk of rapid progression. A trial (NCT02964273) evaluated tolvaptan safety and pharmacodynamics in children (5-17 years). However, progression risk was not part of study eligibility criteria due to lack of validated criteria for risk assessment in children. As risk estimation is important to guide clinical management, baseline characteristics of the study participants were retrospectively evaluated to determine whether risk of rapid disease progression in pediatric ADPKD can be assessed and to identify parameters relevant for risk estimation.

METHODS

Four academic pediatric nephrologists reviewed baseline data and rated participant risk from 1 (lowest) to 5 (highest) based on clinical judgement and the literature. Three primary reviewers independently scored all cases, with each case reviewed by two primary reviewers. For cases with discordant ratings (≥ 2-point difference), the fourth reviewer provided a secondary rating blinded to the primary evaluations. Study participants with discordant ratings and/or for whom data were lacking were later discussed to clarify parameters relevant to risk estimation.

RESULTS

Of 90 evaluable subjects, primary reviews of 69 (77%) were concordant. The proportion considered at risk of rapid progression (final mean rating ≥ 3.5) by age group was: 15-17 years, 27/34 (79%); 12- < 15, 9/32 (28%); 4- < 12, 8/24 (33%). The panelists agreed on characteristics important for risk determination: age, kidney imaging, kidney function, blood pressure, urine protein, and genetics.

CONCLUSIONS

High ratings concordance and agreement among reviewers on relevant clinical characteristics support the feasibility of pediatric risk assessment.

Monoallelic Loss-of-Function IFT140 Pathogenic Variants Cause Autosomal Dominant Polycystic Kidney Disease: A Confirmatory Study With Suspicion of an Additional Cardiac Phenotype

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease. While biallelic variants affecting IFT140 are responsible for Mainzer-Saldino syndrome (characterized by severe ciliopathy causing skeletal abnormalities, kidney disease, and cysts), monoallelic loss-of-function (LoF) variants have been recently reported as an important cause of ADPKD beyond PKD1/2 genes. Herein, we report 6 non-family-related cases of monoallelic IFT140 LoF variants, identified from 1,340 exomes sequenced for nephrological indications in our local database. Every patient presented with polycystic kidney disease. Furthermore, the mother of a boy diagnosed with Mainzer-Saldino syndrome with a biallelic variant affecting IFT140 presented with several bilateral cysts, revealed after kidney imaging, and was found to carry a pathologic frameshift IFT140 variation. As well as this particular Mainzer-Saldino case, our 6 additional patients confirm that heterozygous IFT140 frameshift variants are responsible for the cystic phenotype and kidney failure. Interestingly, of the 6 patients, 2 also exhibited dilated cardiomyopathy, which was of unknown origin, as no genetic cause was found after exome sequencing analysis, suggesting a potential connection between IFT140 and heart disease.

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.

Serum bile acids associate with liver volume in polycystic liver disease and decrease upon treatment with lanreotide

BACKGROUND

Polycystic liver disease (PLD) is a common extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). Bile acids may play a role in PLD pathogenesis. We performed a post-hoc exploratory analysis of bile acids in ADPKD patients, who had participated in a trial on the effect of a somatostatin analogue. Our hypothesis was that serum bile acid levels increase in PLD, and that lanreotide, which reduces liver growth, may also reduce bile acid levels. Furthermore, in PLD, urinary excretion of bile acids might contribute to renal disease.

METHODS

With liquid chromatography-mass spectrometry, 11 bile acids in serum and 6 in urine were quantified in 105 PLD ADPKD patients and 52 age-, sex-, mutation- and eGFR-matched non-PLD ADPKD patients. Sampling was done at baseline and after 120 weeks of either lanreotide or standard care.

RESULTS

Baseline serum levels of taurine- and glycine-conjugated bile acids were higher in patients with larger livers. In PLD patients, multiple bile acids decreased upon treatment with lanreotide but remained stable in untreated subjects. Changes over time did not correlate with changes in liver volume. Urine bile acid levels did not change and did not correlate with renal disease progression.

CONCLUSION

In ADPKD patients with PLD, baseline serum bile acids were associated with liver volume. Lanreotide reduced bile acid levels and has previously been shown to reduce liver volume. However, in this study, the decrease in bile acids was not associated with the change in liver volume.

Metastatic Renal Cell Carcinoma in a Patient With Autosomal Dominant Polycystic Kidney Disease

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) manifests as multiple cysts in the kidneys and liver but can also present with musculoskeletal and cardiovascular abnormalities. ADPKD patients are at increased risk for renal cell carcinoma development. We show the FDG PET/CT findings in a patient with renal cell carcinoma secondary to ADPKD and complicated by worsening pulmonary metastasis. The primary renal tumor shows intense FDG uptake despite no suspicious features with contrast CT.

Evaluation of the Renal and Cardiovascular Effects of Long-Term Tolvaptan Treatment in Autosomal Dominant Polycystic Kidney Disease

INTRODUCTION

Cardiovascular diseases constitute a significant cause of morbidity and mortality in individuals with autosomal dominant polycystic kidney disease (ADPKD). This study aimed to assess the long-term effects of tolvaptan on the kidneys and heart in rapidly progressing ADPKD.

METHODS

Among 354 patients diagnosed with ADPKD, 58 meeting the eligibility criteria for tolvaptan were included in the study. The study comprised two groups with similar demographic and clinical characteristics: 29 patients receiving tolvaptan treatment and 29 in the control group. Several included genetic analysis, magnetic resonance imaging, and echocardiography. Clinical and cardiac changes were recorded in both groups after a 3-year follow-up.

RESULTS

Tolvaptan treatment demonstrated a significant reduction in the rate of eGFR decline compared to the control group. Furthermore, it was observed that tolvaptan could prevent the development of cardiac arrhythmias by inhibiting an increase in QTc interval and heart rate.

CONCLUSION

These findings suggest that, in addition to slowing kidney progression in ADPKD management, tolvaptan may potentially benefit in preventing cardiac complications.

Mortality risk in patients with autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the leading inheritable cause of end-stage renal disease (ESRD). Mortality data specific to patients with ADPKD is currently lacking; thus, the aim of this study was to estimate mortality in patients with ADPKD.

METHODS

We analyzed data from the United States Renal Data System (USRDS) for patients with ADPKD available during the study period of 01/01/2014-12/31/2016, which included a cohort of patients with non-ESRD chronic kidney disease (CKD) and a cohort of patients with ESRD. Mortality rates with 95% confidence intervals (CIs) were calculated overall and by age group, sex, and race for the full dataset and for a subset of patients aged ≥ 65 years. Adjusted mortality hazard ratios (HRs) were calculated using Cox regression modeling by age group, sex, race, and CKD stage (i.e., non-ESRD CKD stages 1-5) or ESRD treatment (i.e., dialysis and transplant).

RESULTS

A total of 1,936 patients with ADPKD and non-ESRD CKD and 37,461 patients with ADPKD and ESRD were included in the analysis. Age-adjusted mortality was 18.4 deaths per 1,000 patient-years in the non-ESRD CKD cohort and 37.4 deaths per 1,000 patient-years in the ESRD cohort. As expected, among the non-ESRD CKD cohort, patients in CKD stages 4 and 5 had a higher risk of death than patients in stage 3 (HR = 1.59 for stage 4 and HR = 2.71 for stage 5). Among the ESRD cohort, patients receiving dialysis were more likely to experience death than patients who received transplant (HR = 2.36). Age-adjusted mortality among patients aged ≥ 65 years in the non-ESRD CKD cohort was highest for Black patients (82.7 deaths per 1,000 patient-years), whereas age-adjusted mortality among patients aged ≥ 65 years in the ESRD cohort was highest for White patients (136.1 deaths per 1,000 patient-years).

CONCLUSIONS

Mortality rates specific to patients aged ≥ 65 years suggest racial differences in mortality among these patients in both non-ESRD CKD and ESRD cohorts. These data fill an important knowledge gap in mortality estimates for patients with ADPKD in the United States.

Long-Term Effects of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease: Predictors of Treatment Response and Safety over 6 Years of Continuous Therapy

Tolvaptan, an oral vasopressin V2 receptor antagonist, reduces renal volume expansion and loss of renal function in patients with autosomal dominant polycystic kidney disease (ADPKD). Data for predictive factors indicating patients more likely to benefit from long-term tolvaptan are lacking. Data were retrospectively collected from 55 patients on tolvaptan for 6 years. Changes in renal function, progression of renal dysfunction (estimated glomerular filtration rate [eGFR], 1-year change in eGFR [ΔeGFR/year]), and renal volume (total kidney volume [TKV], percentage 1-year change in TKV [ΔTKV%/year]) were evaluated at 3-years pre-tolvaptan, at baseline, and at 6 years. In 76.4% of patients, ΔeGFR/year improved at 6 years. The average 6-year ΔeGFR/year (range) minus baseline ΔeGFR/year: 3.024 (-8.77-20.58 mL/min/1.73 m2). The increase in TKV was reduced for the first 3 years. A higher BMI was associated with less of an improvement in ΔeGFR (p = 0.027), and family history was associated with more of an improvement in ΔeGFR (p = 0.044). Hypernatremia was generally mild; 3 patients had moderate-to-severe hyponatremia due to prolonged, excessive water intake in response to water diuresis-a side effect of tolvaptan. Family history of ADPKD and baseline BMI were contributing factors for ΔeGFR/year improvement on tolvaptan. Hyponatremia should be monitored with long-term tolvaptan administration.

Statin therapy in patients with early-stage autosomal dominant polycystic kidney disease: Design and baseline characteristics

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development and continued growth of multiple cysts in the kidneys leading to ultimate loss of kidney function in most patients. Currently, tolvaptan is the only agency approved therapy to slow kidney disease advancement in patients with faster progressing disease underscoring the need for additional ADPKD therapies suitable for all patients. We previously showed that pravastatin slowed kidney disease progression in children and young adults with ADPKD. However, the intervention has not been tested in an adult cohort.

AIMS

The aim of the study is to conduct a single center, randomized, placebo-controlled double-blinded clinical trial to determine the efficacy of pravastatin on slowing kidney disease progression in adult patients with early stage ADPKD.

METHODS

One hundred and fifty adult patients with ADPKD and eGFR ≥60 ml/min/1.73m2 will be enrolled in the study and randomized to receive 40 mg/day pravastatin or placebo for a period of 2-years.

OUTCOMES

The primary outcome of the trial is change in total kidney volume assessed by magnetic resonance imaging (MRI). Secondary outcomes include change in kidney function by iothalamate GFR and renal blood flow and markers of inflammation and oxidative stress.

CONCLUSION

This study will assess the kidney therapeutic benefits of pravastatin in adult patients with ADPKD. The recruitment goal of 150 subjects was attained and the study is ongoing.

REGISTRATION

This study is registered on Clinicaltrials.gov # NCT03273413.

A Case of Autosomal Dominant Polycystic Kidney Disease With Resolution of Massive Pericardial Effusion After Renal Transcatheter Artery Embolization

A 68-year-old woman being treated with hemodialysis for autosomal dominant polycystic kidney disease was admitted for progressive dyspnea over 6 months. On chest radiography, her cardiothoracic ratio had increased from 52.2% 6 months prior, to 71%, and echocardiography revealed diffuse pericardial effusion and right ventricular diastolic insufficiency. A resultant pericardial tamponade was thought to be the cause of the patient's dyspnea, and therefore a pericardiocentesis was performed, with a total of 2,000mL of fluid removed. However, 21 days later the same amount of pericardial fluid had reaccumulated. The second pericardiocentesis was performed, followed by transcatheter renal artery embolization (TAE). The kidneys, which were hard on palpation before TAE, softened immediately after TAE. After resolution of the pericardial effusion was confirmed, the patient was discharged after 24 days in hospital. Twelve months later, the patient was asymptomatic, the cardiothoracic ratio decreased to 48% on chest radiography and computed tomography revealed no reaccumulation of pericardial effusion. This case illustrates a potential relationship between enlarged kidneys in autosomal dominant polycystic kidney disease and pericardial effusion.

Fatal acute portal vein thrombosis associated with hepatic cysts in a patient with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) often involves polycystic liver disease (PLD). In severe cases, PLD can develop various complications. However, fatal acute portal vein thrombosis (APVT) associated with PLD has not been reported. A 64-year-old male reported mild consciousness disorder. He had been under maintenance hemodialysis for end-stage renal disease due to ADPKD with PLD. Because of recurring hepatic cyst infections, he had sustained high levels of C-reactive protein. Regarding the mild consciousness disorder, a diagnosis of hepatic encephalopathy was made based on an elevation of serum ammonia without any other abnormal liver function tests. Several days after his admission, hepatobiliary enzymes elevated, and acute liver failure progressed. Enhanced abdominal computed tomography suggested the possibility of complete occlusion of the portal vein by a thrombus. Based on an absence of obvious portosystemic collaterals, a diagnosis of APVT was made. The patient died 19 days after admission. Patients with PLD with repeated cystic infections have been seen to develop liver failure, and APVT formation may be one cause of the rapid progression of fatal liver failure. In conclusion, this is the first paper to report on the involvement of APVT in patients with PLD.

External carotid artery pseudoaneurysm rupture in a patient with polycystic kidney disease: Case report and review of literature

BACKGROUND

Vascular abnormalities, including dissections and aneurysms, can be found in patients with autosomal dominant kidney disease (ADPKD). While intracranial aneurysms have been reported in 10%-25% of ADPCKD, occurrences at other locations are exceedingly rare.

METHOD

This is a first case report of a patient with ADPCKD who presented with a rupture of the left external carotid artery pseudoaneurysm.

CONCLUSION

Rupture of a carotid artery aneurysm is rare with potentially high morbidity. An endovascular and surgical approach are effective strategies for successful management that depends on etiology, location, and surgeon experience.

Deep learning-based automated kidney and cyst segmentation of autosomal dominant polycystic kidney disease using single vs. multi-institutional data

PURPOSE

This study aimed to investigate if a deep learning model trained with a single institution's data has comparable accuracy to that trained with multi-institutional data for segmenting kidney and cyst regions in magnetic resonance (MR) images of patients affected by autosomal dominant polycystic kidney disease (ADPKD).

METHODS

We used TensorFlow with a Keras custom UNet on 2D slices of 756 MRI images of kidneys with ADPKD obtained from four institutions in the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) study. The ground truth was determined via a manual plus global thresholding method. Five models were trained with 80 % of all institutional data (n = 604) and each institutional data (n = 232, 172, 148, or 52), respectively, and validated with 10 % and tested on an unseen 10 % of the data. The model's performance was evaluated using the Dice Similarity Coefficient (DSC).

RESULTS

The DSCs by the model trained with all institutional data ranged from 0.92 to 0.95 for kidney image segmentation, only 1-2 % higher than those by the models trained with single institutional data (0.90-0.93).In cyst segmentation, however, the DSCs by the model trained with all institutional data ranged from 0.83 to 0.89, which were 2-20 % higher than those by the models trained with single institutional data (0.66-0.86).

CONCLUSION

The UNet performance, when trained with a single institutional dataset, exhibited similar accuracy to the model trained on a multi-institutional dataset. Segmentation accuracy increases with models trained on larger sample sizes, especially in more complex cyst segmentation.

Autosomal dominant polycystic kidney disease with ectopic unilateral multicystic kidney: a case report

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disorder and the fourth cause of death of end-stage renal disease. The disease has a prevalence of 1:400-1:1000 accounting for 10% of patients on dialysis. In most ADPKD patients, bilateral kidneys are similarly affected, with numerous fluid-filled cysts arising from different nephron segments. Only a few cases of ADPKD with ectopic unilateral multicystic kidney have been reported. It has been observed that the deterioration of their kidney function seemed to be quicker than their age- and sex-matched controls and siblings especially when the ectopic kidney is dysplastic.

CASE PRESENTATION

We report a case of a 46-year-old Ghanaian male patient who presented with left flank pain and hematuria with high BP and deranged renal function. Abdominal ultrasonography showed both kidneys to be larger than normal and had multiple cysts of varying sizes with the right kidney located in the right iliac fossa. Follow up Abdominopelvic computer tomographic scan (CT-Scan) without contrast showed enlarged kidneys with the renal parenchyma replaced by innumerable cyst of varying sizes. The right kidney was ectopically located in the right aspect of the pelvis. A diagnosis of ADPKD with right pelvic ectopic multicystic kidney was made. He was put on antihypertensives, analgesia for the left flank pain and to have follow up at the urology and nephrology departments.

CONCLUSION

In most ADPKD patients, bilateral kidneys are similarly affected. Only a few cases of ADPKD with ectopic unilateral multicystic kidney have been reported. It has been observed that the deterioration of their kidney function seemed to be quicker than their age- and sex-matched controls and siblings especially when the ectopic kidney is dysplastic.

[The Management of Patients with Adult Autosomal Dominant Polycystic Kidney Disease (ADPKD) Requires a Multidisciplinary Approach]

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disease. Its main feature is the progressive enlargement of both kidneys with progressive loss of kidney function. ADPKD is the fourth leading cause of terminal renal failure in the world. Even today there are still uncertainties and poor information. Patients too often have a renunciatory and passive attitude toward the disease. However, there are currently no internationally accepted clinical practice guidelines, and there are significant regional variations in approaches to the diagnosis, clinical evaluation, prevention, and treatment of ADPKD. Therefore, we believe it is important to point out the conduct of our specialist outpatient clinic for ADPKD, which from the beginning has developed a multidisciplinary approach (nephrologists, geneticists, psychologists, radiologists, nutritionists) to face the disease at 360° and therefore not only from a purely nephrological point of view. Such a strategy not only enables patients to receive a timely and accurate diagnosis of the disease, but also ensures that they will receive a thorough and focused follow-up over time, that can prevent or at least slow down the disease in its evolution providing patients with a serene awareness of their condition as much as possible.

Cardiovascular Involvement in Patients with Autosomal Dominant Polycystic Kidney Disease: A Review

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease with a prevalence of 1:400 to 1:1,000 in Caucasians. It is caused by mutations in the PKD1 gene located on chromosome 16p13.3 (in about 85% cases) as well as in the PKD2 gene on chromosome 4q13-23. In the Polish population, the disease is associated with PKD1 mutations in 84% of the ADPKD-affected families. PKD1 and PKD2 genes encode the proteins polycystin-1 (PC1) and polycystin-2 (PC2), respectively. The presence of kidney cysts is a characteristic feature in the ADPKD patients. But in the ADPKD patients, cardiovascular abnormalities, such as hypertension (HT) with higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) values, higher left ventricular mass (LVM), intracranial (ICAN) and extracranial aneurysms, and cardiac valve defects, are significantly more common than in the general population.

SUMMARY

According to the literature data, both higher LVM and vascular dysfunction already occur in children and young adults with normal renal function and without HT. Moreover, biventricular diastolic dysfunction, endothelial dysfunction, increased carotid intima-media thickness, and impaired coronary flow velocity reserve are present even in young patients with ADPKD who have normal HT and well-preserved renal function. In patients with ADPKD, hypertension has some specific features; in the youngest age group of children, the prevalence of hypertension is greater if their parents suffer from hypertension; in normotensive young ADPKD-diagnosed individuals, ambulant SBP and DBP values were significantly higher than in age- and gender-matched controls; hypertension appears at least 10 years earlier than spontaneous HT in general population. In adults, HT is often diagnosed before any substantial reduction in the GFR, and a lower nocturnal dip in BP in comparison to hypertensives in the general population. PKD1 and PKD2 gene products (PC1 and PC2 proteins) have been shown to assemble at the plasma membrane and to regulate calcium (Ca2+) entry. A defect in Ca2+ binding mediated by mutations in polycystin proteins is a hypothetical factor contributing to left ventricular mass increase. Altered intracellular Ca2+ handling contributes importantly to impaired contractility associated with heart failure. Impairment of intracellular Ca2+ homeostasis and mitochondrial function has been implicated in the development of LVH.

KEY MESSAGES

It can be assumed that the cause of LVH in ADPKD patients is the natural course of this disease with developing HT and deteriorating kidney function, which may be influenced by the presence of PKD1- and PKD2-mutated gene products: PC1 and PC2 proteins.

Mammalian target of rapamycin inhibition impacts energy homeostasis and induces sex-specific body weight loss in humans

BACKGROUND

Previous data from a 2-year randomized controlled trial (CRAD001ADE12) indicated that mammalian target of rapamycin (mTOR) inhibition by everolimus slowed cyst growth in patients with autosomal-dominant polycystic kidney disease (ADPKD). During the trial, we noted body weight loss in some patients, particularly in women. We hypothesized that everolimus causes body weight reduction by reduced food intake and/or metabolic changes, which could lead to cachexia.

METHODS

Within a sub-analysis of the CRAD001ADE12 trial, body weight course was investigated regarding sex-specific differences in 433 adult ADPKD patients (everolimus, n = 215; placebo, n = 218). One hundred four out of 111 patients who participated in the clinical trial centre in Berlin were evaluated under everolimus/placebo therapy (on drug: everolimus, n = 48; placebo, n = 56) and after therapy (off drug: everolimus, n = 15; placebo, n = 18). Eating habits and nutrient/caloric intake were evaluated by validated questionnaires. Systemic and local metabolism was evaluated in four patients after an oral glucose load (OGL) by using calorimetry and adipose/muscle tissue microdialysis.

RESULTS

Within the 2-year CRAD001ADE12 trial, a significant body weight loss was observed in female patients on everolimus versus placebo (P = 0.0029). Data of the Berlin Cohort revealed that weight loss was greater in women on everolimus versus men (P < 0.01). After 9 months, women and men had lost 2.6 ± 3.8 and 0.8 ± 1.5 kg (P < 0.05) in body weight, respectively, and after 21 months, they had lost 4.1 ± 6.6 and 1.0 ± 3.3 kg (P < 0.05), respectively. On everolimus, caloric intake was significantly lower in women versus men (1510 ± 128 vs. 2264 ± 216 kcal/day, P < 0.05), caused mainly by a lower fat and protein intake in women versus men. Cognitive restraints, disinhibition and hunger remained unchanged. In a subgroup of patients resting metabolic rate was unchanged whereas OGL-induced thermogenesis was reduced (7 ± 2 vs. 11 ± 2 kcal, P < 0.05). Fasting and OGL-induced fat oxidation was increased (P < 0.05) on versus off everolimus. In adipose tissue, fasting lipolytic activity was increased, but lipolytic activity was inhibited similarly after the OGL on versus off everolimus, respectively. In skeletal muscle, postprandial glucose uptake and aerobic glycolysis was reduced in patients on everolimus.

CONCLUSIONS

mTOR inhibition by everolimus induces body weight reduction, specifically in female patients. This effect is possibly caused by a centrally mediated reduced food (fat and protein) intake and by centrally/peripherally mediated increased fat oxidation (systemic) and mobilization (adipose tissue). Glucose uptake and oxidation might be reduced in skeletal muscle. This could lead to cachexia and, possibly, muscle wasting. Therefore, our results have important implications for patients recieving immune-suppressive mTOR inhibition therapy.

Feasibility and impact of ketogenic dietary interventions in polycystic kidney disease: KETO-ADPKD-a randomized controlled trial

Ketogenic dietary interventions (KDIs) are beneficial in animal models of autosomal-dominant polycystic kidney disease (ADPKD). KETO-ADPKD, an exploratory, randomized, controlled trial, is intended to provide clinical translation of these findings (NCT04680780). Sixty-six patients were randomized to a KDI arm (ketogenic diet [KD] or water fasting [WF]) or the control group. Both interventions induce significant ketogenesis on the basis of blood and breath acetone measurements. Ninety-five percent (KD) and 85% (WF) report the diet as feasible. KD leads to significant reductions in body fat and liver volume. Additionally, KD is associated with reduced kidney volume (not reaching statistical significance). Interestingly, the KD group exhibits improved kidney function at the end of treatment, while the control and WF groups show a progressive decline, as is typical in ADPKD. Safety-relevant events are largely mild, expected (initial flu-like symptoms associated with KD), and transient. Safety assessment is complemented by nuclear magnetic resonance (NMR) lipid profile analyses.

Clinical findings, underlying pathogenetic processes and treatment of vascular dysfunction in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder characterized by the development of fluid-filled cysts in the kidneys. The primary cause of ADPKD is mutations in the PKD1 (polycystic kidney disease 1) or PKD2 (polycystic kidney disease 2) gene. Patients with ADPKD often develop a variety of vascular abnormalities, which have a major impact on the structure and function of the blood vessels and can lead to complications such as hypertension, intracranial aneurysm (ICAN), and atherosclerosis. The progression of ADPKD involves intricate molecular and cellular processes that lead to the development of these vascular abnormalities. Our understanding of these processes remains incomplete, and available treatment options are limited. The aim of this review is to delve into the underlying mechanisms of these vascular abnormalities and to explore potential interventions.

Does hydration status influence kidney volume in autosomal dominant polycystic kidney disease?

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive kidney disease where the size of the kidneys is correlated to the stage of kidney failure. Total kidney volume (TKV) is used as a prognostic marker to determine disease stage, progression, and possible effect of treatment. It has been shown that water restriction is associated with reduced kidney volume in healthy subjects. The aim of this study was to evaluate the relationship between TKV and hydration status in ADPKD patients. 40 ADPKD patients with chronic kidney disease stage 1 - 3 were randomized to either 3 hours of water restriction (n = 21) or 1 hour of water loading (n = 19; intake: 20 mL/kg). The patients had a mean age of 38 years (19 - 73) and mean plasma creatinine level of 91 (54 - 178) µmol/L. Magnetic resonance imaging of the kidneys was performed before and after intervention, and TKV was measured using the ellipsoid formula. Water restriction resulted in an insignificant 0.67% increase in TKV (median: 1.48, interquartile range (IQR): 6.1, range: -1. - 4.5). Water loading resulted in an insignificant 2.67% increase in TKV (median: 3.18, IQR: 11.4, range: -3.6 - 7.8). Interestingly, a 7.09% increase in right-kidney volume was found after water loading (median: 5.58, IQR: 9.4 range: 1.9 - 11.3, p < 0.05), whereas the left-kidney volume showed an insignificant decrease of 0.18% after water loading (median: -1.65, IQR: 18.0, range: -12.5 - 5.5). We found in ADPKD patients that neither short-term water restriction nor acute water loading had significant effects, suggesting that the use of TKV for disease staging is independent of hydration level in these patients.

Elevated checkpoint inhibitor expression and Treg cell number in autosomal dominant polycystic kidney disease and their correlation with disease parameters and hypertension

Autosomal dominant polycystic kidney disease (ADPKD) has cancer-like pathophysiology. In this study, we aimed to investigate the phenotype of peripheral blood (PB) T cell subsets and immune checkpoint inhibitor expression of ADPKD patients across different chronic kidney disease (CKD) stages. Seventy-two patients with ADPKD and twenty-three healthy controls were included in the study. The patients were grouped into five different CKD stages, according to glomerular filtration rate (GFR). PB mononuclear cells were isolated and T cell subsets and cytokine production were examined by flow cytometry. CRP levels, height-adjusted total kidney volume (htTKV), rate of hypertension (HT) differed significantly across different GFR stages in ADPKD. T cell phenotyping revealed significantly elevated CD3+ T cells, CD4+, CD8+, double-negative, and double-positive subsets and significantly elevated IFN-γ and TNF-α producing subsets of CD4+, CD8+ cells. The expression of checkpoint inhibitors CTLA-4, PD-1, and TIGIT by T cell subsets was also increased to various extent. Additionally, Treg cell numbers and suppressive markers CTLA-4, PD-1, and TIGIT were significantly elevated in ADPKD patients' PB. Treg CTLA4 expression and CD4CD8DP T cell frequency in patients with HT were significantly higher. Lastly, HT and increased htTKV and higher frequency of PD1+ CD8SP were found to be risk factors for rapid disease progression. Our data provide the first detailed analyses of checkpoint inhibitor expression by PB T cell subsets during stages of ADPKD, and that a higher frequency of PD1+ CD8SP cells is associated with rapid disease progression.

Prostaglandin E2, Osmoregulation, and Disease Progression in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Prostaglandin E2 (PGE2) plays a physiological role in osmoregulation, a process that is affected early in autosomal dominant polycystic kidney disease (ADPKD). PGE2 has also been implicated in the pathogenesis of ADPKD in preclinical models, but human data are limited. Here, we hypothesized that urinary PGE2 excretion is associated with impaired osmoregulation, disease severity, and disease progression in human ADPKD.

METHODS

Urinary excretions of PGE2 and its metabolite (PGEM) were measured in a prospective cohort of patients with ADPKD. The associations between urinary PGE2 and PGEM excretions, markers of osmoregulation, eGFR and height-adjusted total kidney volume were assessed using linear regression models. Cox regression and linear mixed models were used for the longitudinal analysis of the associations between urinary PGE2 and PGEM excretions and disease progression defined as 40% eGFR loss or kidney failure, and change in eGFR over time. In two intervention studies, we quantified the effect of starting tolvaptan and adding hydrochlorothiazide to tolvaptan on urinary PGE2 and PGEM excretions.

RESULTS

In 562 patients with ADPKD (61% female, eGFR 63±28 ml/min per 1.73 m 2 ), higher urinary PGE2 or PGEM excretions were independently associated with higher plasma copeptin, lower urine osmolality, lower eGFR, and greater total kidney volume. Participants with higher baseline urinary PGE2 and PGEM excretions had a higher risk of 40% eGFR loss or kidney failure (hazard ratio, 1.28; 95% confidence interval [CI], 1.13 to 1.46 and hazard ratio, 1.50; 95% CI, 1.26 to 1.80 per two-fold higher urinary PGE2 or PGEM excretions) and a faster change in eGFR over time (-0.39 [95% CI, -0.59 to -0.20] and -0.53 [95% CI, -0.75 to -0.31] ml/min per 1.73 m 2 per year). In the intervention studies, urinary PGEM excretion was higher after starting tolvaptan, while urinary PGE2 excretion was higher after adding hydrochlorothiazide to tolvaptan.

CONCLUSIONS

Higher urinary PGE2 and PGEM excretions in patients with ADPKD are associated with impaired osmoregulation, disease severity, and progression.

The safety and efficacy of tolvaptan in the treatment of patients with autosomal dominant polycystic kidney disease: A systematic review and meta-analysis

BACKGROUND

The irreversible progression of autosomal dominant polycystic kidney disease (ADPKD) to end-stage renal disease (ESRD) is delayed by tolvaptan. Therefore, we aim to systematically estimate and evaluate the efficacy and safety of tolvaptan in the treatment of ADPKD.

METHODS

Two reviewers independently searched all published randomized controlled trials studies in PubMed, EMBASE, Web of Science and Cochrane databases, extracted data, assessed bias risk and rated the quality of evidence. Data were analyzed by the RevMan software.

RESULTS

We identified 8 trials including 2135 patients. Both of the decline of estimated glomerular filtration rate (eGFR) [MD=1.89, 95% CI (0.74, 3.04), P=0.001] and total kidney volume (TKV) [MD=-3.32, 95% CI (-4.57, -2.07), P<0.001] were delayed in tolvaptan group compared with placebo group in ADPKD patients. The use of tolvaptan delayed TKV progression in the different-month subgroups [MD=-69.99, 95% CI (-91.05, -48.94), P<0.001]. Tolvaptan reduced renal pain [RR=0.66, 95% CI (0.54, 0.81), P<0.001] and hematuria events [RR=0.55, 95% CI (0.41, 0.74), P<0.001] in ADPKD patients. However, the prevalence of thirst [RR=2.75, 95% CI (2.34, 3.24), P<0.001] and nocturia events [RR=3.01, 95% CI (1.27, 7.11), P=0.01] were increased in tolvaptan group. There is no significant difference of hypertension events [RR=0.92, 95% CI (0.82, 1.03), P=0.13] in tolvaptan group compared placebo group.

CONCLUSIONS

This meta-analysis suggests that tolvaptan may improve clinical progression in patients with ADPKD without significantly increasing the risk of adverse reactions.

Double Heterozygous Pathogenic Variants in the LOX and PKD1 Genes in a 5-Year-Old Patient with Thoracic Aortic Aneurysm and Polycystic Kidney Disease

Familial thoracic aortic aneurysms and dissections may occur as an isolated hereditary trait or as part of connective tissue disorders with Mendelian inheritance, but severe cardiovascular disease in pediatric patients is extremely rare. There is growing knowledge on pathogenic variants causing the disease; however, much of the phenotypic variability and gene-gene interactions remain to be discovered. We present a case report of a 5.5-year-old girl with an aortic aneurysm and concomitant polycystic kidney disease. Whole exome sequencing was performed, followed by family screening by amplicon deep sequencing and diagnostic imaging studies. In the proband, two pathogenic variants were identified: p.Tyr257Ter in the LOX gene inherited from her mother, and p.Thr2977Ile in the PKD1 gene inherited from her father. All adult carriers of either of these variants showed symptoms of aortic disease. We conclude that the coexistence of two independent genetic variants in the proband may be the reason for an early onset of disease.

Subclinical Target Organ Damage in a Sample of Children with Autosomal Dominant Polycystic Kidney Disease: A Pilot Study

Background and Objectives: Hypertension and vascular damage can begin in adolescents affected by Autosomal Dominant Polycystic Kidney Disease (ADPKD). This study aimed to evaluate markers of vascular damage and left ventricular geometry in a sample of children with ADPKD. Materials and Methods: Several vascular measurements were obtained: ambulatory blood pressure monitoring (ABPM), carotid intima-media thickness (cIMT), carotid distensibility coefficient (cDC), pulse wave velocity (PWV), and echocardiographic measurements (relative wall thickness (RWT) and left ventricular mass index (LVMI)). Results: Eleven ADPKD children were recruited (four females and seven males, mean age 9.5 ± 3.2 years). Four children were hypertensive at the ABPM, five were normotensive, and for two ABPM was not available. RWT was tendentially high (mean 0.47 ± 0.39). Eight patients had concentric cardiac remodeling, while one patient had cardiac hypertrophy. cIMT was above the 95° percentile for sex and height in 80% of the children (0.5 ± 0.005 mm). The average PWV and cDC were between the normal range (5.5 ± 4.6 m/s and 89.6 ± 16.1 × 10-3/KPa, respectively). We observed a positive correlation between the PWV and RWT (r = 0.616; p = 0.044) and a negative correlation between cDC and RWT (r = -0.770; p = 0.015). Cardiovascular damages (cIMT > 95° percentile) were found in normotensive patients. Conclusions: Increased RWT and high cIMT, indicating subclinical organ damage, are already present in ADPKD children. RWT was significantly correlated to that of cDC and PWV, implying that vascular stiffening is associated with cardiac remodeling. None of the children had an alteration in renal function. Subclinical cardiovascular damage preceded the decline in glomerular filtration rate.

The association of urinary epidermal growth factors with ADPKD disease severity and progression

BACKGROUND

The epidermal growth factor receptor (EGFR) pathway is involved in kidney tissue repair and growth. Preclinical interventional data and scarce human data have suggested a role for this pathway in the pathophysiology of autosomal dominant polycystic kidney disease (ADPKD), while other data have suggested that its activation is causally linked to repair of damaged kidney tissue. We hypothesize that urinary EGFR ligands, as a reflection of EGFR activity, are associated with kidney function decline in ADPKD in the context of tissue repair following injury, and as the disease progresses as a sign of insufficient repair.

METHODS

In the present study, we measured the EGFR ligands, EGF and heparin binding-EGF (HB-EGF), in 24-h urine samples of 301 ADPKD patients and 72 age- and sex-matched living kidney donors to dissect the role of the EGFR pathway in ADPKD. During a median follow-up of 2.5 years, the association of urinary EGFR ligand excretion with annual change in estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume in ADPKD patients was analyzed using mixed-models methods, and the expression of three closely related EGFR family receptors in ADPKD kidney tissue was investigated by immunohistochemistry. Additionally, the effect of reducing renal mass (after kidney donation), was assessed to investigate whether urinary EGF matches this reduction and thus reflects the amount of remaining healthy kidney tissue.

RESULTS

At baseline, urinary HB-EGF did not differ between ADPKD patients and healthy controls (P = .6), whereas a lower urinary EGF excretion was observed in ADPKD patients [18.6 (11.8-27.8)] compared with healthy controls [51.0 (34.9-65.4) μg/24 h, P < .001]. Urinary EGF was positively associated with baseline eGFR (R = 0.54, P < .001) and a lower EGF was strongly associated with a more rapid GFR decline, even when adjusted for ADPKD severity markers (β = 1.96, P < .001), whereas HB-EGF was not. Expression of the EGFR, but not other EGFR-related receptors, was observed in renal cysts but was absent in non-ADPKD kidney tissue. Finally, unilateral nephrectomy resulted in a decrease of 46.4 (-63.3 to -17.6) % in urinary EGF excretion, alongside a decrease of 35.2 ± 7.2% in eGFR and 36.8 ± 6.9% in measured GFR (mGFR), whereas maximal mGFR (measured after dopamine induced hyperperfusion) decreased by 46.1 ± 7.8% (all P < .001).

CONCLUSIONS

Our data suggest that lower urinary EGF excretion may be a valuable novel predictor for kidney function decline in patients with ADPKD.

Factors Associated With the Development and Severity of Polycystic Liver in Patients With Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Factors related to the development and severity of polycystic liver disease (PLD) have not been well established. We aimed to evaluate the genetic and epidemiologic risk factors of PLD in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Adult patients with inherited cystic kidney disease were enrolled from May 2019 to May 2021. Demographic, clinical, and laboratory data were collected at the initial study visit. The severity of PLD was graded based on the height-adjusted total liver volume: < 1,000 mL/m (Gr1), 1,000-1,800 mL/m (Gr2), and > 1,800 mL/m (Gr3). Targeted exome sequencing was done by a gene panel including 89 ciliopathy-related genes. We searched out the relative factors to the presence and the severity of PLD using logistic regression analysis.

RESULTS

Of 602 patients with typical ADPKD, 461 (76.6%) patients had PLD. The patients with PLD showed female predominance and a higher frequency of other ADPKD-related complications. The genetic variants with truncating mutation of PKD1 (PKD1-protein-truncating [PT]) or PKD2 commonly affected the development and severity of PLD. An older age, female sex, and higher kidney volume with Mayo classification 1C-1E was significantly associated with the development of PLD, but not with the severity of PLD. On the other hand, higher body mass index, lower hemoglobin, and higher alkaline phosphatase (ALP) were the significant risk factors of severe PLD (≥ Gr2).

CONCLUSION

Hepatic involvement in ADPKD could be related to kidney manifestations and genetic variants including PKD1-PT or PKD2. Monitoring hemoglobin and ALP and evaluating the genetic variants might help predict severe PLD.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0005580.

Vascular Complications in Autosomal Dominant Polycystic Kidney Disease: Perspectives, Paradigms, and Current State of Play

Autosomal dominant polycystic kidney disease (ADPKD) is the leading cause of inherited kidney disease with significant contributions to CKD and end-stage kidney disease. The underlying polycystin proteins (PC1 and PC2) have widespread tissue expression and complex functional roles making ADPKD a systemic disease. Vascular complications, particularly intracranial aneurysms (ICA) are the most feared due to their potential for devastating neurological complications and sudden death. Intracranial aneurysms occur in 8-12% of all patients with ADPKD, but the risk is intensified 4-5-fold in those with a positive family history. The basis for this genetic risk is not well understood and could conceivably be due to features of the germline mutation with a significant contribution of other genetic modifiers and/or environmental factors. Here we review what is known about the natural history and genetics of unruptured ICA in ADPKD including the prevalence and risk factors for aneurysm formation and subarachnoid hemorrhage. We discuss two alternative screening strategies and recommend a practical algorithm that targets those at highest risk for ICA with a positive family history for screening.

Cardiovascular implications of hypertensive autosomal dominant polycystic kidney disease: a systematic review and meta-analysis

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is among the most common inherited kidney diseases. Hypertension is a frequent cardiovascular manifestation, especially in adults, but elevated blood pressure is also found in children and adolescents. Acknowledgment of pediatric hypertension early is critical, as it can result in serious complications long-term if left undiagnosed.

OBJECTIVE

We aim to identify the influence of hypertension on cardiovascular outcomes, mainly left ventricular hypertrophy, carotid intima media thickness, and pulse wave velocity.

METHODS

We performed an extensive search on Medline, Embase, CINAHL, and Web of Science databases through March 2021. Original studies with a mix of retrospective, prospective, case-control studies, cross sectional studies, and observational studies were included in the review. There was no restriction on age group.

RESULTS

The preliminary search yielded 545 articles with 15 articles included after inclusion and exclusion criteria. In this meta-analysis, LVMI (SMD: 3.47 (95% CI: 0.53-6.41)) and PWV (SMD: 1.72 (95% CI: 0.08-3.36)) were found to be significantly higher in adults with ADPKD compared to non-ADPKD; however, CIMT was not found to be significantly different. Also, LVMI was observed to be significantly higher among hypertensive adults with ADPKD (n = 56) as compared to adults without ADPKD (SMD: 1.43 (95% CI: 1.08-1.79)). Fewer pediatric studies were available with heterogeneity among patient populations and results.

CONCLUSIONS

Adult patients with ADPKD were found to have worse indicators of cardiovascular outcomes, including LVMI and PWV, as compared to non-ADPKD. This study demonstrates the importance of identifying and managing hypertension, especially early, in this population. Further research, particularly in younger patients, is necessary to further elucidate the relationship between hypertension in patients with ADPKD and cardiovascular disease.

REGISTRATION NUMBER

PROSPERO REGISTRATION: 343,013.

Assessing the Risk of Progression to Kidney Failure in Patients With Autosomal Dominant Polycystic Kidney Disease

While autosomal dominant polycystic kidney disease (ADPKD) is a dichotomous diagnosis, substantial variability in disease severity exists. Identification of inherited risk through family history, genetic testing, and environmental risk factors through clinical assessment are important components of risk assessment for optimal management of patients with ADPKD. Genetic testing is especially helpful in cases with diagnostic uncertainty, particularly in cases with no apparent family history, in young cases (age less than 25 years) where a definitive diagnosis is sought, or in atypical presentations with early, severe, or discordant findings. Currently, risk assessment in ADPKD may be performed with the use of age-adjusted estimated glomerular filtration rate thresholds, evidence of rapid estimated glomerular filtration rate decline on serial measurements, age- and height-adjusted total kidney volume by Mayo Clinic Imaging Classification, or evidence of early hypertension and urological complications combined with PKD1 or PKD2 mutation class; however, caveats exist with each of these approaches. Fine-tuning of risk stratification with advanced imaging features and biomarkers is the subject of research but is not yet ready for general clinical practice. While conservative treatment strategies will be advised for all patients, those with the greatest rate of disease progression will have the most benefit from aggressive disease-modifying therapy. In this narrative review, we will summarize the evidence behind the clinical assessment and risk stratification of patients with ADPKD.

Dialysis and Transplant Considerations in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth leading cause of kidney replacement therapy. Unfortunately, the need for dialysis or kidney transplantation is a foreseeable outcome for many patients affected by ADPKD. We review some of the unique issues that should be considered in the management of patients with ADPKD who require dialysis or kidney transplantation. The choice of dialysis modality may be influenced by the enlarged kidneys and liver, but peritoneal dialysis should not be excluded as an option, as studies do not consistently show that there is an increased risk for technique failure or peritonitis. The optimal kidney replacement therapy option remains kidney transplantation; however, nephrectomy may be needed if there is insufficient space for the allograft. Living donor candidates from at-risk families need to be excluded from carrying the disease either by diagnostic imaging criteria or genetic testing. Other potential transplant issues, such as malignancy and cardiovascular and metabolic risks, should also be recognized. Despite these issues, patients with ADPKD requiring dialysis or kidney transplantation generally have more favorable outcomes as compared to those with other causes of chronic kidney disease. Further studies are still needed to personalize the therapeutic approach for those receiving kidney replacement therapy and eventually improve clinical outcomes.

Management of Hypertension and Associated Cardiovascular Disease in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease is the most commonly inherited disease of the kidneys affecting an estimated 12,000,000 people in the world. Autosomal dominant polycystic kidney disease is a systemic disease, with a wide range of associated features that includes hypertension, valvular heart diseases, cerebral aneurysms, aortic aneurysms, liver cysts, abdominal hernias, diverticulosis, gross hematuria, urinary tract infections, nephrolithiasis, pancreatic cysts, and seminal vesicle cysts. The cardiovascular anomalies are somewhat different than in the general population and also chronic kidney disease population, with higher morbidity and mortality rates. This review will focus on cardiovascular diseases associated with autosomal dominant polycystic kidney disease and their management.

Dual diagnosis of autosomal dominant polycystic kidney disease and sickle cell disease in a teenage male

BACKGROUND

Sickle cell disease (SCD) and autosomal dominant polycystic kidney disease (ADPKD) are relatively common genetic conditions with considerable overlap in clinical presentation. In addition to similarities between the signs and symptoms in sickle cell nephropathy and ADPKD, more than half of SCD patients have kidney cysts. The co-occurrence of these two diseases has not been previously reported in the literature.

CASE DIAGNOSIS/TREATMENT

A 16-year-old Black male with SCD had bilateral kidney enlargement and multiple simple cysts on ultrasound. Although kidney cysts are significantly more common in individuals affected with SCD, genetic testing with a broad kidney gene panel was performed to explore the possible presence of another underlying genetic cause of his cysts, in addition to SCD. A dual diagnosis of SCD and ADPKD was made following the identification of two copies of the common pathogenic sickle cell HBB variant (c.20A > T, p.Glu7Val) and a pathogenic missense variant in PKD1 (c.8311G > A, p.Glu2771Lys).

CONCLUSIONS

SCD and ADPKD differ in pathophysiological mechanisms and treatment regimens. As such, it will be paramount for this teenager to be closely monitored for signs of diminished kidney function and to be co-managed as he transitions to adult care to ensure proper treatment and management. Early identification of individuals with both SCD and a co-occurring condition is crucial to ensuring proper clinical management. Furthermore, identifying and reporting additional patients with SCD and ADPKD dual diagnoses will help us to understand the co-occurring disease course and optimal treatments.

Utility of new image-derived biomarkers for autosomal dominant polycystic kidney disease prognosis using automated instance cyst segmentation

New image-derived biomarkers for patients affected by autosomal dominant polycystic kidney disease are needed to improve current clinical management. The measurement of total kidney volume (TKV) provides critical information for clinicians to drive care decisions. However, patients with similar TKV may present with very different phenotypes, often requiring subjective decisions based on other factors (e.g., appearance of healthy kidney parenchyma, a few cysts contributing significantly to overall TKV, etc.). In this study, we describe a new technique to individually segment cysts and quantify biometric parameters including cyst volume, cyst number, parenchyma volume, and cyst parenchyma surface area. Using data from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) study the utility of these new parameters was explored, both quantitatively as well as visually. Total cyst number and cyst parenchyma surface area showed superior prediction of the slope of estimated glomerular filtration rate decline, kidney failure and chronic kidney disease stages 3A, 3B, and 4, compared to TKV. In addition, presentations such as a few large cysts contributing significantly to overall kidney volume were shown to be much better stratified in terms of outcome predictions. Thus, these new image biomarkers, which can be obtained automatically, will have great utility in future studies and clinical care for patients affected by autosomal dominant polycystic kidney disease.

Renin-angiotensin system activation: may it increase frequency of obstructive sleep apnea in patients with autosomal dominant polycystic kidney disease?

PURPOSE

Renin-angiotensin system (RAS) hyperactivity is a common entity in both autosomal dominant polycystic kidney disease (ADPKD) and obstructive sleep apnea (OSA). We aimed to investigate the frequency of OSA in adults with ADPKD either with stages 3-4 or stages 1-2 chronic kidney disease (CKD) and evaluate the effect of RAS blockade on OSA in these patients.

METHODS

This is a comparative, prospective, two-center clinical study. Eligible patients with ADPKD were enrolled in a polysomnography (PSG) study. Presence of OSA in patients with ADPKD was compared with individuals who underwent polisomnography study due to OSA symptoms. A subgroup analysis was performed in terms of the presence of OSA in ADPKD with eGFR values lower or higher than 60 ml/min/1.73 m2 (stages 3-4 and stages 1-2 CKD, respectively).

RESULTS

Frequency of OSA (65%) was higher than in the general population and similar between the two groups (p = 0.367). Patients with ADPKD and eGFR ≥ 60 ml/min/1.73 m2 presented a similar frequency of OSA to the control group (p = 0.759). However, OSA was significantly more frequent in ADPKD with eGFR < 60 ml/min/1.73 m2 (p = 0.018). Subgroup analysis revealed that presence of OSA also was significantly higher in ADPKD with lower eGFR levels (eGFR < 60 ml/min/1.73 m2 and eGFR > 60 ml/min/1.73 m2) 14/17 (82%) and 12/23 (52%), respectively (p: 0.048).

CONCLUSION

As kidney disease progresses, uremia and related factors of renal failure rather than RAS activation seem to play a more important role for the development of OSA in patients with ADPKD.

Cystic Kidney Diseases in Children and Adults: Differences and Gaps in Clinical Management

Cystic kidney diseases, when broadly defined, have a wide differential diagnosis extending from recessive diseases with a prenatal or pediatric diagnosis, to the most common autosomal-dominant polycystic kidney disease primarily affecting adults, and several other genetic or acquired etiologies that can manifest with kidney cysts. The most likely diagnoses to consider when assessing a patient with cystic kidney disease differ depending on family history, age stratum, radiologic characteristics, and extrarenal features. Accurate identification of the underlying condition is crucial to estimate the prognosis and initiate the appropriate management, identification of extrarenal manifestations, and counseling on recurrence risk in future pregnancies. There are significant differences in the clinical approach to investigating and managing kidney cysts in children compared with adults. Next-generation sequencing has revolutionized the diagnosis of inherited disorders of the kidney, despite limitations in access and challenges in interpreting the data. Disease-modifying treatments are lacking in the majority of kidney cystic diseases. For adults with rapid progressive autosomal-dominant polycystic kidney disease, tolvaptan (V2-receptor antagonist) has been approved to slow the rate of decline in kidney function. In this article, we examine the differences in the differential diagnosis and clinical management of cystic kidney disease in children versus adults, and we highlight the progress in molecular diagnostics and therapeutics, as well as some of the gaps meriting further attention.

Cerebrovascular Pulsatility Index Is Reduced in Autosomal Dominant Polycystic Kidney Disease

INTRODUCTION

Cerebrovascular dysfunction, characterized by increased brain pulsatile flow, reduced cerebrovascular reactivity, and cerebral hypoperfusion precedes the onset of dementia and is linked to cognitive dysfunction. Autosomal dominant polycystic kidney disease (ADPKD) may increase the risk of dementia, and intracranial aneurysms are more prevalent in ADPKD patients. However, cerebrovascular function has not been previously characterized in patients with ADPKD.

METHODS

Using transcranial Doppler, we compared middle cerebral artery (MCA) pulsatility index (PI, cerebrovascular stiffness) and MCA blood velocity response to hypercapnia (normalized for blood pressure and end-tidal CO2, cerebrovascular reactivity) in patients with early-stage ADPKD versus age-matched healthy controls. We also administered the NIH cognitive toolbox (cognitive function) and measured carotid-femoral pulse-wave velocity (PWV, aortic stiffness).

RESULTS

Fifteen participants with ADPKD (9F, 27 ± 4 yrs, eGFR: 106 ± 22 mL/min/1.73 m2) were compared to 15 healthy controls (8F, 29 ± 4 yrs, eGFR: 109 ± 14 mL/min/1.73 m2). MCA PI was unexpectedly lower in ADPKD (0.71 ± 0.07) versus controls (0.82 ± 0.09 AU; p < 0.001); however, normalized MCA blood velocity in response to hypercapnia did not differ between groups (2.0 ± 1.2 vs. 2.1 ± 0.8 %Δ/mm Hg; p = 0.85). Lower MCA PI was associated with a lower crystalized composite score (cognition), which persisted after adjustment for age, sex, eGFR, and education (β = 0.58, p = 0.007). There was no association of MCA PI with carotid-femoral PWV (r = 0.01, p = 0.96), despite greater carotid-femoral PWV in ADPKD, suggesting MCA PI reflects vascular properties other than arterial stiffness (such as low wall shear stress) in ADPKD.

DISCUSSION/CONCLUSION

MCA PI is lower in patients with ADPKD. Follow-up research on this observation is merited as low PI has been associated with intracranial aneurysm in other populations.

Barriers and facilitators to the transplant process among patients living with polycystic kidney disease: a qualitative Approach

BACKGROUND

Kidney transplant is the gold standard for renal replacement therapy in patients with autosomal dominant polycystic kidney disease (ADPKD), which is the fourth leading cause of kidney failure. Despite the medical and economic benefits of preemptive kidney transplant over dialysis before transplant, only 9-21% of qualifying patients receive preemptive transplants. Given the low rates of preemptive transplant, the aim of this study was to determine perceived facilitators and barriers to preemptive transplant among ADPKD patients using a qualitative approach.

METHODS

Data were collected between July 2021 and January 2022 from virtual individual semi-structured interviews of 16 adult participants with ADPKD. Qualitative analysis of the recorded interviews was conducted to generate themes.

RESULTS

Our findings revealed two themes specific for facilitators to preemptive transplant (social support and patient agency) and three themes specific to barriers for preemptive transplant (inadequate social support, gaps in knowledge, and institutional and systemic policies). The results also include various subthemes and the application of these themes to the social ecological model.

CONCLUSIONS

These findings suggest that increasing social support and patient agency, such as through patient navigator programs and encouraging effective communication between health care providers and patients, can facilitate the transplant process. Increasing dissemination of transplant knowledge from institutions and systems to patients through paired kidney exchange education and live donor outreach can also increase timely access to preemptive kidney transplants for patients with ADPKD. Our findings are limited by our single site study in the US, which may not apply to individuals experiencing different social, cultural, and health access conditions.

Surgical Management of Autosomal Dominant Polycystic Kidney Disease: Principles and Current Practice

Autosomal dominant polycystic kidney disease is the third most common cause of renal failure with no definitive treatment available that can directly target the development and growth of the cysts. Endeavours are being made to retard the growth of the cysts and preservation of renal function through medical treatment. However, 50% of the autosomal dominant polycystic kidney disease-affected persons develop complications and end-stage renal disease by the age of fifty-five and need surgical intervention for the management of complications, creation of dialysis access and renal transplantation. This review highlights the principles and current practice pertinent to the surgical management of autosomal dominant polycystic kidney disease.

Keywords

polycystic kidney disease; nephrectomy; transplantation.

Characteristics and Distribution of Intracranial Aneurysms in Patients with Autosomal Dominant Polycystic Kidney Disease Compared with the General Population: A Meta-Analysis

Key Points

IAs location distribution in patients with ADPKD differ from the ones in non-ADPKD patients IAs in patients with ADPKD are more commonly located in the anterior circulation and in large caliber arteries Because of IA multiplicity and singular IA distribution, patients with ADPKD represent a special population who need to be closely followed

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic condition associated with intracranial aneurysms (IAs). The associated pathophysiology remains unknown, but an association with wall shear stress is suspected. Cerebral arterial location is the principal factor influencing IA natural history. This study aims to compare IA location-specific distribution between ADPKD and non-ADPKD patients.

Methods

The ADPKD group comprised data from a systematic review of the literature (2016–2020, N =7) and three cohorts: integrated biomedical informatics for the management of cerebral aneurysms, Novosibirsk, and Unruptured Cerebral Aneurysms Study. The non-ADPKD group was formed from the integrated biomedical informatics for the management of cerebral aneurysms, Unruptured Cerebral Aneurysms Study, International Stroke Genetics Consortium, and the Finnish cohort from the literature. Patients and IAs characteristics were compared between ADPKD and non-ADPKD groups, and a meta-analysis for IA locations was performed.

Results

A total of 1184 IAs from patients with ADPKD were compared with 21,040 IAs from non-ADPKD patients. In total, 78.6% of patients with ADPKD had hypertension versus 39.2% of non-ADPKD patients. A total of 32.4% of patients with ADPKD were smokers versus 31.5% of non-ADPKD patients. In total, 30.1% of patients with ADPKD had a positive family history for IA versus 15.8% of the non-ADPKD patients. Patients with ADPKD showed a higher rate of IA multiplicity (33.2% versus 23.1%). IAs from patients with ADPKD showed a significant predominance across the internal carotid and middle cerebral arteries. Posterior communicating IAs were more frequently found in the non-ADPKD group. The meta-analysis confirmed a predominance of IAs in the patients with ADPKD across large caliber arteries (odds ratio [95% confidence interval]: internal carotid artery: 1.90 [1.10 to 3.29]; middle cerebral artery: 1.18 [1.02–1.36]). Small diameter arteries, such as the posterior communicating, were observed more in non-ADPKD patients (0.21 [0.11–0.88]).

Conclusion

This analysis shows that IAs diagnosed in patients with ADPKD are more often localized in large caliber arteries from the anterior circulation in comparison with IAs in non-ADPKD patients. It shows that primary cilia driven wall shear stress vessel remodeling to be more critical in cerebral anterior circulation large caliber arteries.

Native nephrectomy in patients with autosomal dominant polycystic kidney disease in the kidney transplant program - single-center retrospective results of 2000-2020

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease that leads to chronic renal failure in about half of patients. It is a multisystemic disease with a predominance of kidney involvement, which significantly worsens the patient's health. Controversial issues include the indication and the timing and technique of nephrectomy of native polycystic kidneys.

METHODS

A retrospective observational study focused on the surgical aspects of patients with ADPKD who underwent native nephrectomy at our institution. The group included patients operated on in the period 1/1/2000-31/12/2020. A total of 115 patients with ADPKD were enrolled (14.7% of all transplant recipients). We evaluated the basic demographic data, type of surgery, indications and complications in this group.

RESULTS

Native nephrectomy was performed in 68 out of a total of 115 (59%) patients. Unilateral nephrectomy was done in 22 (32%) patients and bilateral in 46 (68%). The most common indications were infections (42 patients, 36%), pain (31 patients, 27%), hematuria (14 patients, 12%), gastrointestinal reasons (1 patient, 1%), respiratory reasons (1 patient, 1%), obtaining a site for transplantation (17 patients, 15%) and suspected tumor (5 patients, 4%).

CONCLUSION

Native nephrectomy is recommended in symptomatic kidneys, or in asymptomatic kidneys when it is necessary to obtain a place for kidney transplantation, and in kidneys where a tumor is suspected.