Autosomal Dominant Polycystic Kidney Patients May Be Predisposed to Various Cardiomyopathies

Autosomal dominant polycystic kidney disease: an overview of recent genetic and clinical advances

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inherited kidney disease, characterized by the progressive development of multiple kidney cysts, leading to a gradual decline in kidney function. ADPKD is also the fourth leading cause of kidney failure (KF) in adults. In addition to kidney manifestations, ADPKD is associated with various extrarenal features, including liver cysts, cardiovascular abnormalities, intracranial aneurysms, and chronic pain with significant impact on patients' quality of life. While several disease-modifying agents have been tested in ADPKD, tolvaptan remains the only approved drug by the US Food and Drug Administration. The Mayo Imaging Classification is currently the most practical tool for predicting rate of kidney disease progression in ADPKD. This review provides a comprehensive overview of ADPKD, focusing on its genetics, pathophysiology, clinical presentation, management, and prognostic tools. Advances in diagnostic imaging and genetic testing have improved the early detection of ADPKD, allowing better classification of patients and prediction of KF. The review also discusses current therapeutic approaches to ADPKD, including tolvaptan, a vasopressin V2-receptor antagonist. Additionally, we address specific issues in children and pregnant individuals with ADPKD. Despite substantial progress in understanding ADPKD, there is a large need for additional effective treatments and prognostic markers to provide a more personalized care for these patients.

Autosomal Dominant Polycystic Kidney Disease: A Review

Importance

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive development of kidney cysts and is the most common inherited kidney disorder worldwide. ADPKD accounts for 5% to 10% of kidney failure in the US and Europe, and its prevalence in the US is 9.3 per 10 000 individuals.

Observations

ADPKD is typically diagnosed in individuals aged 27 to 42 years and is primarily caused by pathogenic variants in the PKD1 (78%) or PKD2 (15%) genes. Most persons with ADPKD have an affected parent, but de novo disease is suggested in 10% to 25% of families. More than 90% of patients older than 35 years have hepatic cysts, which may cause abdominal discomfort and occasionally require medical or surgical intervention. Hypertension affects 70% to 80% of patients with ADPKD, and approximately 9% to 14% develop intracranial aneurysms, which have a rupture rate of 0.57 per 1000 patient-years. Approximately 50% of individuals with ADPKD require kidney replacement therapy by 62 years of age. The severity of kidney disease can be quantified using the Mayo Imaging Classification (MIC), which stratifies patients based on total kidney volume adjusted for height and age and ranges from 1A to 1E. Patients with MIC 1C to MIC 1E have larger kidneys because of more rapid growth (6%-10% per year) compared with those with MIC 1A and 1B (1%-5% per year) and have earlier progression to kidney replacement therapy, which occurs at a mean age of 58.4 years for MIC 1C, 52.5 years for MIC 1D, and 43.4 years for MIC 1E. Optimal management of ADPKD includes systolic blood pressure lower than 120 mm Hg for most patients, but lower than 110/75 mm Hg for patients with MIC 1C to 1E who have an estimated glomerular filtration rate (eGFR) greater than 60 mL/min/1.73 m2 and are younger than 50 years, dietary sodium restriction (<2000 mg/d), weight management, and adequate hydration (>2.5 L daily). The vasopressin type 2 receptor antagonist tolvaptan reduces the annual rate of eGFR decline by 0.98 to 1.27 mL/min/1.73 m2 and is indicated for patients with MIC 1C to 1E or an eGFR decline greater than 3 mL/min/1.73 m2 per year to slow disease progression and delay the onset of kidney failure.

Conclusion

ADPKD is the most common genetic kidney disease worldwide and is characterized by progressive development of kidney cysts. Patients typically have hypertension and liver cysts, and 9% to 14% develop intracranial aneurysms. First-line treatment includes blood pressure control, dietary and weight management, and adequate hydration. Tolvaptan reduces the rate of eGFR decline for those at high risk of rapid progression to kidney failure.

Echocardiographic characteristics of autosomal dominant polycystic kidney disease

Cardiovascular complications in patients with autosomal dominant polycystic kidney disease (ADPKD) are frequently investigated extrarenal manifestations with contradictory outcomes. The primary goal of this study is to explore the prevalence of cardiovascular abnormalities using echocardiography and analyze their associations with clinical characteristics at different stages of chronic kidney disease (CKD) progression in ADPKD patients. We included sixty-eight patients in the study. All patients underwent transthoracic echocardiography using GE Vingmed Ultrasound (GE Norway Health Tech, Oslo, Norway). Demographic information, prior medical history, and antihypertensive medication use were recorded. To diagnose the rapid progression of CKD, creatinine levels were measured twice, with a one-year interval. Analysis revealed left ventricular hypertrophy (LVH) in over 40% of ADPKD patients, as indicated by various LVH parameters. Notably, a decline in estimated glomerular filtration rate (eGFR) after one year of observation was associated with increased left ventricular mass. Other prevalent findings included asymptomatic left ventricular diastolic dysfunction (ALVDD) in 39% of patients, left atrium (LA) enlargement in 39%, and mild valvular regurgitations in 80%. Ejection fraction, aortic root dimension, and the prevalence of mitral valve prolapse were not significantly increased. Cardiac indices did not differ substantially across the different eGFR stages. LVH, LA enlargement, ALVDD and valvular regurgitations are characteristics of cardiac phenotype in ADPKD. Cardiac indices were not different across different stages of CKD pointing towards the diagnosis of ADPKD being the main drive of their occurrence.

What happened to the left ventricular non-compaction cardiomyopathy? to be or not to be: This is the question

For several years, left ventricular non-compaction (LVNC) was considered as a true cardiomyopathy and several definitions have followed one another. Particularly, LVNC was characterized by prominent left ventricular trabeculae separated from deep intertrabecular recesses. Several echocardiographic criteria and cardiac magnetic resonance imaging (CMR) criteria have been used to diagnose LVNC, leading to overestimate the diagnosis of LVNC in patients with other diseases and/or physiological conditions. Left ventricular hypertrabeculation (LVH) can be present in several cardiac diseases and physiological conditions: heart failure with reduced ejection fraction, thalassemia and other hematological diseases, pregnancy, athlete's heart. Thus, the presence of LVH does not necessarily indicate the presence of an LVNC. In addition, the great heterogeneity of clinical manifestations has raised concerns regarding the existence of a true LVNC as a cardiomyopathy. In fact, LVNC ranges from genetic to acquired and even transient conditions, isolated forms or forms associated with other cardiomyopathies, congenital heart diseases or syndromes with a very different prognosis. Thus, considering LVH as a manifestation of various diseases and physiological conditions, the recent 2023 ESC guidelines on cardiomyopathies did not include LVNC among cardiomyopathies, but they suggested using the term "LVH" rather than LVNC, to describe this phenotype especially when it is transient or of adult-onset. In this review, we aimed to make an excursion on LVNC, from its initial description to the present day, to understand why current guidelines decided to consider LVH as a phenotypic trait rather than a distinct cardiomyopathy.

A case report of autosomal recessive polycystic kidney disease with noncompaction of ventricular myocardium: coincidence or different manifestations of ciliopathy?

BACKGROUND

Autosomal recessive polycystic kidney disease (ARPKD) is a rare inherited cystic disease characterized by bilateral renal cyst formation and congenital liver fibrosis. Cardiovascular disorders such as noncompaction of ventricular myocardium (NVM) have not been reported with ARPKD.

CASE PRESENTATION

A 5-month-old girl was examined after presenting with a fever and turbid urine for one day and was diagnosed as urinary tract infection. Urinary ultrasound showed multiple round, small cysts varying in size in both kidneys. Genetic testing revealed two heterozygous mutations and one exon deletion in the polycystic kidney and hepatic disease 1 gene, indicating a diagnosis of ARPKD. During hospitalization, she was found to have chronic heart failure after respiratory tract infection, with an ejection fraction of 29% and fraction shortening of 13%. When the patient was 15 months old, it was found that she had prominent trabeculations and deep intertrabecular recesses with the appearance of blood flow from the ventricular cavity into the intertrabecular recesses by echocardiography. The noncompaction myocardium was 0.716 cm and compaction myocardium was 0.221 cm (N/C = 3.27), indicating a diagnosis of NVM. Liver and kidney function remained normal during four-year follow-up.

CONCLUSIONS

This is the first report of NVM in a patient with ARPKD. It is unsure if the coexistence of NVM and ARPKD is a coincidence or they are different manifestations of ciliary dysfunction in the heart and kidneys.

Autosomal Dominant Polycystic Kidney Disease: Extrarenal Involvement

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disorder, but kidneys are not the only organs involved in this systemic disorder. Individuals with the condition may display additional manifestations beyond the renal system, involving the liver, pancreas, and brain in the context of cystic manifestations, while involving the vascular system, gastrointestinal tract, bones, and cardiac valves in the context of non-cystic manifestations. Despite kidney involvement remaining the main feature of the disease, thanks to longer survival, early diagnosis, and better management of kidney-related problems, a new wave of complications must be faced by clinicians who treated patients with ADPKD. Involvement of the liver represents the most prevalent extrarenal manifestation and has growing importance in the symptom burden and quality of life. Vascular abnormalities are a key factor for patients' life expectancy and there is still debate whether to screen or not to screen all patients. Arterial hypertension is often the earliest onset symptom among ADPKD patients, leading to frequent cardiovascular complications. Although cardiac valvular abnormalities are a frequent complication, they rarely lead to relevant problems in the clinical history of polycystic patients. One of the newest relevant aspects concerns bone disorders that can exert a considerable influence on the clinical course of these patients. This review aims to provide the "state of the art" among the extrarenal manifestation of ADPKD.

RETRACTED: Left Ventricular Non-Compaction in Children: Aetiology and Diagnostic Criteria

Left ventricular non-compaction (LVNC) is a heterogeneous myocardial disorder characterized by prominent trabeculae protruding into the left ventricular lumen and deep intertrabecular recesses. LVNC can manifest in isolation or alongside other heart muscle diseases. Its occurrence among children is rising due to advancements in imaging techniques. The origins of LVNC are diverse, involving both genetic and acquired forms. The clinical manifestation varies greatly, with some cases presenting no symptoms, while others typically manifesting with heart failure, systemic embolism, and arrhythmias. Diagnosis mainly relies on assessing heart structure using imaging tools like echocardiography and cardiac magnetic resonance. However, the absence of a universally agreed-upon standard and limitations in diagnostic criteria have led to ongoing debates in the scientific community regarding the most reliable methods. Further research is crucial to enhance the diagnosis of LVNC, particularly in early life stages.

Beyond Loss of Kidney Function: Patient Care in Autosomal Dominant Polycystic Kidney Disease

Patients with autosomal dominant polycystic kidney disease benefit from specialized care over their lifetimes, starting with diagnosis of the condition with ongoing discussion of both the renal course and extra-renal issues. Both renal and extra-renal issues may continue to cause major morbidity even after successful kidney transplant or initiation of RRT, and extra-renal disease aspects should always be considered as part of routine management. In this review, we will focus on updates in pain/depression screening, cardiac manifestations, liver and pancreatic cysts, kidney stone management, and genetic counseling. In some instances, we have shared our current clinical practice rather than an evidence-based guideline. We anticipate more standardization of care after the release of the Kidney Disease Improving Global Outcomes guidelines for management in autosomal dominant polycystic kidney disease later this year.

Cardiovascular Manifestations and Management in ADPKD

Cardiovascular disease (CVD) is the major cause of mortality in autosomal dominant polycystic kidney disease (ADPKD) and contributes to significant burden of disease. The manifestations are varied, including left ventricular hypertrophy (LVH), intracranial aneurysms (ICAs), valvular heart disease, and cardiomyopathies; however, the most common presentation and a major modifiable risk factor is hypertension. The aim of this review is to detail the complex pathogenesis of hypertension and other extrarenal cardiac and vascular conditions in ADPKD drawing on preclinical, clinical, and epidemiological evidence. The main drivers of disease are the renin-angiotensin-aldosterone system (RAAS) and polycystin-related endothelial cell dysfunction, with the sympathetic nervous system (SNS), nitric oxide (NO), endothelin-1 (ET-1), and asymmetric dimethylarginine (ADMA) likely playing key roles in different disease stages. The reported rates of some manifestations, such as LVH, have decreased likely due to the use of antihypertensive therapies; and others, such as ischemic cardiomyopathy, have been reported with increased prevalence likely due to longer survival and higher rates of chronic disease. ADPKD-specific screening and management guidelines exist for hypertension, LVH, and ICAs; and these are described in this review.

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.

Congenital abnormalities of heart and kidney

Patients with congenital anomalies of the kidney and urinary tract (CAKUT) may be at risk for congenital cardiac defects or cardiomyopathies as comorbidities. It is crucial to recognize the coexistence of cardiac abnormalities and CAKUT and recommend screening for cardiac involvement in CAKUT patients using echocardiography.

Autosomal dominant and autosomal recessive polycystic kidney disease: hypertension and secondary cardiovascular effect in children

Autosomal dominant (ADPKD) and autosomal recessive (ARPKD) polycystic kidney disease are the most widely known cystic kidney diseases. They are significantly different from each other in terms of genetics and clinical manifestations. Hypertension is one of the main symptoms in both diseases, but the age of onset and secondary cardiovascular complications are significantly different. Most ARPKD children are hypertensive in the first year of life and need high doses of hypertensive drugs. ADPKD patients with a very early onset of the disease (VEOADPKD) develop hypertension similarly to patients with ARPKD. Conversely, a significantly lower percentage of patients with classic forms of ADPKD develops hypertension during childhood, although probably more than originally thought. Data published in the past decades show that about 20%–30% of ADPKD children are hypertensive. Development of hypertension before 35 years of age is a known risk factor for more severe disease in adulthood. The consequences of hypertension on cardiac geometry and function are not well documented in ARPKD due to the rarity of the disease, the difficulties in collecting homogeneous data, and differences in the type of parameters evaluated in different studies. Overall, left ventricular hypertrophy (LVH) has been reported in 20%–30% of patients and does not always correlate with hypertension. Conversely, cardiac geometry and cardiac function are preserved in the vast majority of hypertensive ADPKD children, even in patients with faster decline of kidney function. This is probably related to delayed onset of hypertension in ADPKD, compared to ARPKD. Systematic screening of hypertension and monitoring secondary cardiovascular damage during childhood allows initiating and adapting antihypertensive treatment early in the course of the disease, and may limit disease burden later in adulthood.

Excessive Trabeculation of the Left Ventricle: JACC: Cardiovascular Imaging Expert Panel Paper

Excessive trabeculation, often referred to as "noncompacted" myocardium, has been described at all ages, from the fetus to the adult. Current evidence for myocardial development, however, does not support the formation of compact myocardium from noncompacted myocardium, nor the arrest of this process to result in so-called noncompaction. Excessive trabeculation is frequently observed by imaging studies in healthy individuals, as well as in association with pregnancy, athletic activity, and with cardiac diseases of inherited, acquired, developmental, or congenital origins. Adults with incidentally noted excessive trabeculation frequently require no further follow-up based on trabecular pattern alone. Patients with cardiomyopathy and excessive trabeculation are managed by cardiovascular symptoms rather than the trabecular pattern. To date, the prognostic role of excessive trabeculation in adults has not been shown to be independent of other myocardial disease. In neonates and children with excessive trabeculation and normal or abnormal function, clinical caution seems warranted because of the reported association with genetic and neuromuscular disorders. This report summarizes the evidence concerning the etiology, pathophysiology, and clinical relevance of excessive trabeculation. Gaps in current knowledge of the clinical relevance of excessive trabeculation are indicated, with priorities suggested for future research and improved diagnosis in adults and children.

Cardiac Manifestations in Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD): A Single-Center Study

Key Points

Cardiovascular disease—a key driver of morbidity in CKD—is common in patients with autosomal dominant polycystic kidney disease (ADPKD). Pathologic echocardiography findings, including valvular defects, aortic root dilation, and hypertrophy, are found in most patients with ADPKD. These findings correlate with parameters indicating disease progression in ADPKD. Echocardiography should be offered to all patients with ADPKD.

Background

ADPKD is the most common monogenetic kidney disease and results in kidney failure in >75% of affected individuals. As a systemic disorder, ADPKD is associated with a variety of extrarenal manifestations, including cardiac manifestations, that affect the majority of patients. We characterized the cardiac involvement in patients with ADPKD from the German AD(H)PKD registry and compared them with kidney donor candidates as controls.

Methods

In this single-center cohort study, we evaluated 141 patients with ADPKD (44.17±11.23 years) from the German AD(H)PKD registry and 60 kidney donor candidates (55.08±10.21 years). All patients underwent clinical examination, abdominal MRI, and transthoracic echocardiography.

Results

Of the patients with ADPKD, 65% showed hypertrophy of the left ventricle (as defined by an end-diastolic interventricular septal wall thickness [IVSd] >10 mm) compared with 55% in control patients. Mitral regurgitation was the most common finding among 54% of patients with ADPKD who exhibited valvular dysfunction, albeit mild in most patients. Interestingly, left ventricular ejection fraction (LV-EF) differed significantly between both groups, with higher values in patients with ADPKD (64%±6% versus 60%±6%), whereas other parameters, including IVSd, left ventricular end-diastolic diameter (LVEDD), tricuspid annular plane systolic excursion (TAPSE), and pressure gradients across the aortic and tricuspid valve were similar between groups. Correlations of echocardiographic parameters with markers of disease progression revealed statistically significant associations for aortic root diameter (P =0.01), the pressure gradient across the aortic valve (AV dPmax; P =0.0003), and IVSd (P =0.0001), indicating rapid kidney disease progression may also be associated with cardiac findings.

Conclusion

Cardiovascular abnormalities are prevalent in patients with ADPKD. Considering the importance of cardiovascular disease for outcomes in CKD, early management and possibly prevention are important goals of any treatment scheme. Consequently, echocardiography should be offered to all patients with ADPKD in routine management.

Hypertrophic and fibrotic human PKD hearts are associated with macrophage infiltration and abnormal TGF-β1 signaling

Autosomal dominant polycystic kidney disease (PKD) is a hereditary kidney disorder which can affect cardiovascular system. Cardiac hypertrophy and cardiomyopathy in PKD have been reported by echocardiography analyses, but histopathology analyses of human PKD hearts have never been examined. The current studies evaluated human heart tissues from five subjects without PKD (non-PKD) and five subjects with PKD. Our histopathology data of human PKD hearts showed an increased extracellular matrix associated with cardiac hypertrophy and fibrosis. Hypertrophy- and fibrosis-associated pathways involving abnormal cardiac structure were next analyzed. We found that human PKD myocardium was infiltrated by inflammatory macrophage M1 and M2; expression of transforming growth factor (TGF-β₁) and its receptor were upregulated with overexpression of pSmad3 and β-catenin. Because patients with PKD have an abnormal kidney function that could potentially affect heart structure, we used a heart-specific PKD mouse model to validate that cardiac hypertrophy and fibrosis were independent from polycystic kidney. In summary, our data show that hearts from human PKD were characterized by hypertrophy, interstitial fibrosis, perivascular fibrosis, and conduction system fibrosis with upregulated TGF-β₁ and its receptor. We suggest that such structural abnormalities may predispose to systolic and diastolic cardiac dysfunction in the PKD myocardium.

Multiplexed measurement of cell type-specific calcium kinetics using high-content image analysis combined with targeted gene disruption

Kinetic analysis of intracellular calcium (Ca2+) in cardiomyocytes is commonly used to determine the pathogenicity of genetic mutations identified in patients with dilated cardiomyopathy (DCM). Conventional methods for measuring Ca2+ kinetics target whole-well cultured cardiomyocytes and therefore lack information concerning individual cells. Results are also affected by heterogeneity in cell populations. Here, we developed an analytical method using CRISPR/Cas9 genome editing combined with high-content image analysis (HCIA) that links cell-by-cell Ca2+ kinetics and immunofluorescence images in thousands of cardiomyocytes at a time. After transfecting cultured mouse cardiomyocytes that constitutively express Cas9 with gRNAs, we detected a prolonged action potential duration specifically in Serca2a-depleted ventricular cardiomyocytes in mixed culture. To determine the phenotypic effect of a frameshift mutation in PKD1 in a patient with DCM, we introduced the mutation into Cas9-expressing cardiomyocytes by gRNA transfection and found that it decreases the expression of PKD1-encoded PC1 protein that co-localizes specifically with Serca2a and L-type voltage-gated calcium channels. We also detected the suppression of Ca2+ amplitude in ventricular cardiomyocytes with decreased PC1 expression in mixed culture. Our HCIA method provides comprehensive kinetic and static information on individual cardiomyocytes and allows the pathogenicity of mutations to be determined rapidly.

Polycystin-1 Is a Crucial Regulator of BIN1 Expression and T-Tubule Remodeling Associated with the Development of Dilated Cardiomyopathy

Cardiomyopathy is commonly observed in patients with autosomal dominant polycystic kidney disease (ADPKD), even when they have normal renal function and arterial pressure. The role of cardiomyocyte polycystin-1 (PC1) in cardiovascular pathophysiology remains unknown. PC1 is a potential regulator of BIN1 that maintains T-tubule structure, and alterations in BIN1 expression induce cardiac pathologies. We used a cardiomyocyte-specific PC1-silenced (PC1-KO) mouse model to explore the relevance of cardiomyocyte PC1 in the development of heart failure (HF), considering reduced BIN1 expression induced T-tubule remodeling as a potential mechanism. PC1-KO mice exhibited an impairment of cardiac function, as measured by echocardiography, but no signs of HF until 7-9 months of age. Of the PC1-KO mice, 43% died suddenly at 7 months of age, and 100% died after 9 months with dilated cardiomyopathy. Total BIN1 mRNA, protein levels, and its localization in plasma membrane-enriched fractions decreased in PC1-KO mice. Moreover, the BIN1 + 13 isoform decreased while the BIN1 + 13 + 17 isoform was overexpressed in mice without signs of HF. However, BIN1 + 13 + 17 overexpression was not observed in mice with HF. T-tubule remodeling and BIN1 score measured in plasma samples were associated with decreased PC1-BIN1 expression and HF development. Our results show that decreased PC1 expression in cardiomyocytes induces dilated cardiomyopathy associated with diminished BIN1 expression and T-tubule remodeling. In conclusion, positive modulation of BIN1 expression by PC1 suggests a novel pathway that may be relevant to understanding the pathophysiological mechanisms leading to cardiomyopathy in ADPKD patients.

Hypertrophic cardiomyopathy secondary to tacrolimus therapy in a kidney transplant patient: A case report and focused review of the literature

Calcineurin inhibitors have become a pillar of immunosuppressive treatment in solid organ transplant recipients. Several case reports have shown hypertrophic and dilated cardiomyopathy as an adverse effect to tacrolimus therapy. We present the case of a kidney transplant recipient woman who developed hypertrophic cardiomyopathy due to tacrolimus therapy.

Endothelium-Specific Deficiency of Polycystin-1 Promotes Hypertension and Cardiovascular Disorders

Background:

Autosomal dominant polycystic kidney disease is the most frequent hereditary kidney disease and is generally due to mutations in PKD1 and PKD2 , encoding polycystins 1 and 2. In autosomal dominant polycystic kidney disease, hypertension and cardiovascular disorders are highly prevalent, but their mechanisms are partially understood.

Methods:

Since endothelial cells express the polycystin complex, where it plays a central role in the mechanotransduction of blood flow, we generated a murine model with inducible deletion of Pkd1 in endothelial cells ( Cdh5-Cre ERT2 ; Pkd1 fl/fl ) to specifically determine the role of endothelial polycystin-1 in autosomal dominant polycystic kidney disease.

Results:

Endothelial deletion of Pkd1 induced endothelial dysfunction, as demonstrated by impaired flow-mediated dilatation of resistance arteries and impaired relaxation to acetylcholine, increased blood pressure and prevented the normal development of arteriovenous fistula. In experimental chronic kidney disease induced by subtotal nephrectomy, endothelial deletion of Pkd1 further aggravated endothelial dysfunction, vascular remodeling, and heart hypertrophy.

Conclusions:

Altogether, this study provides the first in vivo demonstration that specific deletion of Pkd1 in endothelial cells promotes endothelial dysfunction and hypertension, impairs arteriovenous fistula development, and potentiates the cardiovascular alterations associated with chronic kidney disease.

Echocardiographic Abnormalities in Autosomal Dominant Polycystic Kidney Disease (ADPKD) Patients

Cardiovascular abnormalities, such as left ventricular hypertrophy and valvular disorders, particularly mitral valve prolapse, have been described as highly prevalent among adult patients with autosomal dominant polycystic kidney disease (ADPKD). The present study aimed to assess echocardiographic parameters in a large sample of both normotensive and hypertensive ADPKD patients, regardless of kidney function level, and evaluate their association with clinical and laboratorial parameters. A retrospective study consisted of the analysis of clinical, laboratorial, and transthoracic echocardiograms data retrieved from the medical records of young adult ADPKD outpatients. A total of 294 patients (120 M/174 F, 41.0 ± 13.8 years old, 199 hypertensive and 95 normotensive) with a median estimated glomerular filtration rate (eGFR) of 75.5 mL/min/1.73 m² were included. The hypertensive group (67.6%) was significantly older and exhibited significantly lower eGFR than the normotensive one. Increased left ventricular mass index (LVMI) was seen in 2.0%, mitral valve prolapse was observed in 3.4%, mitral valve regurgitation in 15.3%, tricuspid valve regurgitation in 16.0%, and aortic valve regurgitation in 4.8% of the whole sample. The present study suggested that the prevalence of mitral valve prolapse was much lower than previously reported, and increased LVMI was not seen in most adult ADPKD patients.

Cardiovascular Outcomes in Kidney Transplant Recipients With ADPKD

Introduction

Cardiovascular disease leads to high morbidity and mortality in patients with kidney failure. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disease with various cardiac abnormalities. Details on the cardiovascular profile of patients with ADPKD who are undergoing kidney transplantation (KT) and its progression are limited.

Methods

Echocardiographic data within 2 years before KT (1993-2020), and major adverse cardiovascular events (MACEs) after transplantation were retrieved. The primary outcome is to assess cardiovascular abnormalities on echocardiography at the time of transplantation in ADPKD as compared with patients without ADPKD matched by sex (male, 59.4%) and age at transplantation (57.2 ± 8.8 years).

Results

Compared with diabetic nephropathy (DN, n = 271) and nondiabetic, patients without ADPKD (NDNA) (n = 271) at the time of KT, patients with ADPKD (n = 271) had lower rates of left ventricular hypertrophy (LVH) (39.4% vs. 66.4% vs. 48.6%), mitral (2.7% vs. 6.3% vs. 7.45) and tricuspid regurgitations (1.8% vs. 6.6% vs. 7.2%). Patients with ADPKD had less diastolic (25.3%) and systolic (5.6%) dysfunction at time of transplantation. Patients with ADPKD had the most favorable post-transplantation survival (median 18.7 years vs. 12.0 for diabetic nephropathy [DN] and 13.8 years for nondiabetic non-ADPKD [NDNA]; P < 0.01) and the most favorable MACE-free survival rate (hazard ratio = 0.51, P < 0.001). Patients with ADPKD had worsening of their valvular function and an increase in the sinus of Valsalva diameter post-transplantation (38.2 vs. 39.9 mm, P < 0.01).

Conclusion

ADPKD transplant recipients have the most favorable cardiac profile pretransplantation with better patient survival and MACE-free survival rates but worsening valvular function and increasing sinus of Valsalva diameter, as compared with patients with other kidney diseases.

Consensus document on autosomal dominant polycystic kindey disease from the Spanish Working Group on Inherited Kindey Diseases. Review 2020

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on kidney replacement therapy (KRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.

Echocardiographic Findings and Genotypes in Autosomal Dominant Polycystic Kidney Disease

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cystic kidney disease and is well known to have extrarenal complications. Cardiovascular complications are of particular clinical relevance because of their morbidity and mortality; however, unclear is why they occur so frequently in patients with ADPKD and whether they are related to the genotypes.

Methods

We extracted and retrospectively analyzed clinical data on patients with ADPKD who underwent echocardiography and whose genotype was confirmed by genetic testing between April 2016 and December 2020. We used next-generation sequencing to compare cardiac function, structural data, and the presence of cardiac valvular disease in patients with 1 of 3 genotypes: PKD1, PKD2, and non-PKD1, 2.

Results

This retrospective study included 65 patients with ADPKD. Patients were divided into 3 groups: PKD1, n = 32; PKD2, n = 12; and non-PKD1, 2, n = 21. The prevalence of mitral regurgitation (MR) was significantly higher in the PKD1 group than in the PKD2 and non-PKD1, 2 group (46.9% vs. 8.3% vs. 19.0%, respectively; p = 0.02). In contrast, no significant difference was found for other cardiac valve complications.

Conclusion

This study found a significantly higher prevalence of MR in patients with the PKD1 genotype than in those with the PKD2 or non-PKD1, 2 genotypes. Physicians may need to perform echocardiography earlier and more frequently in patients with ADPKD and the PKD1 genotype and to control fluid volume and blood pressure more strictly in these patients to prevent future cardiac events.

Disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice

Cardiovascular manifestations account for marked morbi-mortality in autosomal dominant polycystic kidney disease (ADPKD). Pkd1- and Pkd2-deficient mice develop cardiac dysfunction, however the underlying mechanisms remain largely unclear. It is unknown whether impairment of polycystin-1 cleavage at the G-protein-coupled receptor proteolysis site, a significant ADPKD mutational mechanism, is involved in this process. We analyzed the impact of polycystin-1 cleavage on heart metabolism using Pkd1^V/V mice, a model unable to cleave this protein and with early cardiac dysfunction. Pkd1^V/V hearts showed lower levels of glucose and amino acids and higher lipid levels than wild-types, as well as downregulation of p-AMPK, p-ACCβ, CPT1B-Cpt1b, Ppara, Nppa and Acta1. These findings suggested decreased fatty acid β-oxidation, which was confirmed by lower oxygen consumption by Pkd1^V/V isolated mitochondria using palmitoyl-CoA. Pkd1^V/V hearts also presented increased oxygen consumption in response to glucose, suggesting that alternative substrates may be used to generate energy. Pkd1^V/V hearts displayed a higher density of decreased-size mitochondria, a finding associated with lower MFN1, Parkin and BNIP3 expression. These derangements were correlated with increased apoptosis and inflammation but not hypertrophy. Notably, Pkd1^V/V neonate cardiomyocytes also displayed shifts in oxygen consumption and p-AMPK downregulation, suggesting that, at least partially, the metabolic alterations are not induced by kidney dysfunction. Our findings reveal that disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice, expanding the understanding of heart dysfunction associated with Pkd1 deficiency and likely with human ADPKD.

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.

Polycystic Liver Disease: Advances in Understanding and Treatment

Polycystic liver disease (PLD) is a group of genetic disorders characterized by progressive development of cholangiocyte-derived fluid-filled hepatic cysts. PLD is the most common manifestation of autosomal dominant and autosomal recessive polycystic kidney diseases and rarely occurs as autosomal dominant PLD. The mechanisms of PLD are a sequence of the primary (mutations in PLD-causative genes), secondary (initiation of cyst formation), and tertiary (progression of hepatic cystogenesis) interconnected molecular and cellular events in cholangiocytes. Nonsurgical, surgical, and limited pharmacological treatment options are currently available for clinical management of PLD. Substantial evidence suggests that pharmacological targeting of the signaling pathways and intracellular processes involved in the progression of hepatic cystogenesis is beneficial for PLD. Many of these targets have been evaluated in preclinical and clinical trials. In this review, we discuss the genetic, molecular, and cellular mechanisms of PLD and clinical and preclinical treatment strategies. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Polycystin-1 regulates cardiomyocyte mitophagy

Polycystin-1 (PC1) is a transmembrane protein found in different cell types, including cardiomyocytes. Alterations in PC1 expression have been linked to mitochondrial damage in renal tubule cells and in patients with autosomal dominant polycystic kidney disease. However, to date, the regulatory role of PC1 in cardiomyocyte mitochondria is not well understood. The analysis of mitochondrial morphology from cardiomyocytes of heterozygous PC1 mice (PDK1^+/- ) using transmission electron microscopy showed that cardiomyocyte mitochondria were smaller with increased mitochondria density and circularity. These parameters were consistent with mitochondrial fission. We knocked-down PC1 in cultured rat cardiomyocytes and human-induced pluripotent stem cells (iPSC)-derived cardiomyocytes to evaluate mitochondrial function and morphology. The results showed that downregulation of PC1 expression results in reduced protein levels of sub-units of the OXPHOS complexes and less functional mitochondria (reduction of mitochondrial membrane potential, mitochondrial respiration, and ATP production). This mitochondrial dysfunction activates the elimination of defective mitochondria by mitophagy, assessed by an increase of autophagosome adapter protein LC3B and the recruitment of the Parkin protein to the mitochondria. siRNA-mediated PC1 knockdown leads to a loss of the connectivity of the mitochondrial network and a greater number of mitochondria per cell, but of smaller sizes, which characterizes mitochondrial fission. PC1 silencing also deregulates the AKT-FoxO1 signaling pathway, which is involved in the regulation of mitochondrial metabolism, mitochondrial morphology, and processes that are part of cell quality control, such as mitophagy. Together, these data provide new insights about the controls that PC1 exerts on mitochondrial morphology and function in cultured cardiomyocytes dependent on the AKT-FoxO1 signaling pathway.

Cardiac Involvement in Autosomal Dominant Polycystic Kidney Disease

Cardiovascular disorders are the main complication in autosomal dominant polycystic kidney disease (ADPKD). contributing to both morbidity and mortality. This review considers clinical studies unveiling cardiovascular features in patients with ADPKD. Additionally, it focuses on basic science studies addressing the dysfunction of the polycystin proteins located in the cardiovascular system as a contributing factor to cardiovascular abnormalities. In particular, the effects of polycystin proteins’ deficiency on the cardiomyocyte function have been considered.

[Cardiovascular disorders in autosomal dominant polycystic kidney disease]

Autosomal dominant polycystic kidney disease is the most frequent genetic kidney disease. Cardiovascular disorders associated with autosomal dominant polycystic kidney disease are multiple and may occur early in life. In autosomal dominant polycystic kidney disease cardiovascular morbidity and mortality are related both to the nonspecific consequences of chronic kidney disease and to the particular phenotype of autosomal dominant polycystic kidney disease. Compared to the general population, patients with autosomal dominant polycystic kidney disease present an increased prevalence of hypertension, left ventricular hypertrophy, atrial fibrillation, valvular diseases, aneurisms and arterial dissections. This review article provides an update on cardiovascular disorders associated with autosomal dominant polycystic kidney disease and recent pathophysiological developments.

Novel non-cystic features of polycystic kidney disease: having new eyes or seeking new landscapes

For decades, researchers have been trying to decipher the complex pathophysiology of autosomal dominant polycystic kidney disease (ADPKD). So far these efforts have led to clinical trials with different candidate treatments, with tolvaptan being the only molecule that has gained approval for this indication. As end-stage kidney disease due to ADPKD has a substantial impact on health expenditures worldwide, it is likely that new drugs targeting kidney function will be developed. On the other hand, recent clinical observations and experimental data, including PKD knockout models in various cell types, have revealed unexpected involvement of many other organs and cell systems of variable severity. These novel non-cystic features, some of which, such as lymphopenia and an increased risk to develop infections, should be validated or further explored and might open new avenues for better risk stratification and a more tailored approach. New insights into the aberrant pathways involved with abnormal expression of PKD gene products polycystin-1 and -2 could, for instance, lead to a more directed approach towards early-onset endothelial dysfunction and subsequent cardiovascular disease. Furthermore, a better understanding of cellular pathways in PKD that can explain the propensity to develop certain types of cancer can guide post-transplant immunosuppressive and prophylactic strategies. In the following review article we will systematically discuss recently discovered non-cystic features of PKD and not well-established characteristics. Overall, this knowledge could enable us to improve the outcome of PKD patients apart from ongoing efforts to slow down cyst growth and attenuate kidney function decline.

Sudden Unexpected Death of Infantile Dilated Cardiomyopathy with JPH2 and PKD1 Gene Variants

A Japanese girl with polycystic kidney disease (PKD) developed normally, but at 8 months of age, she was hospitalized for acute onset dyspnea. On the day after admission to hospital, her general condition suddenly became worse. An echocardiogram showed left ventricular dilatation with thin walls, severe mitral valve regurgitation, and a reduced ejection fraction. She died of acute cardiac failure 3 hours after the sudden change. Postmortem analysis with light microscopy showed disarray of cardiomyocytes without obvious infiltration of lymphocytes, and we diagnosed her heart failure as idiopathic dilated cardiomyopathy (DCM). Clinical exome sequencing showed compound heterozygous variants in JPH2 (p.T237A/p.I414L) and a heterozygous nonsense mutation in PKD1 (p.Q4193*). To date, several variants in the JPH2 gene have been reported to be pathogenic for adult-onset hypertrophic cardiomyopathy or DCM in an autosomal dominant manner and infantile-onset DCM in an autosomal recessive manner. Additionally, autosomal dominant polycystic kidney disease is a systemic disease associated with several extrarenal manifestations, such as cardiomyopathy. Here we report a sudden infant death case of DCM and discuss the genetic variants of DCM and PKD.

The role of multimodality imaging in the diagnosis of left ventricular noncompaction

Left ventricular noncompaction (LVNC) is a heterogeneous entity and, in reality, a likely spectrum of disease which is clinically associated with arrhythmia, thromboembolic complications and sudden cardiac death. With the emergence of cardiac MRI (cMRI), the phenotype is increasingly more prevalent, resulting in clinical uncertainty regarding prognosis and management. The currently accepted hypothesis suggests an early embryonic arrest of the normal, sequential myocardial compaction process. LVNC is observed in isolation or in association with congenital heart disease, neuromuscular disease or a vast array of genetic cardiomyopathies. Definition of the entity varies among international society guidelines with differences both within and between imaging modalities, predominantly echocardiography and cMRI. Long-term prognostic data are emerging but due to the intrinsic variability in reported prevalence, selection bias and lack of pathological to prognostic correlation, there are many uncertainties regarding clinical management. This review seeks to clarify the role of multimodality imaging in diagnosis and management of the disease. We discuss the sensitivity and specificity of the current diagnostic criteria, as well as the nuances in diagnosis using the available imaging modalities.

Polycystins, ADPKD, and Cardiovascular Disease

Cardiovascular disorders are the most common cause of mortality in autosomal dominant polycystic kidney disease (ADPKD). This review considers recent clinical and basic science studies that address the contributing factors of cardiovascular dysfunction in ADPKD. In particular, attention is placed on how dysfunction of the polycystin proteins located in the cardiovascular system contributes to extrarenal manifestations of ADPKD.

Left ventricular hypertrophy in a contemporary cohort of autosomal dominant polycystic kidney disease patients

Background

Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD) often develop hypertension in childhood or early adulthood. Although this could result in left ventricular hypertrophy (LVH), a major risk factor for cardiovascular morbidity and mortality, prior studies of LVH in ADPKD have yielded conflicting results. We estimated the prevalence of LVH using consensus echocardiography criteria and examined the independent association of ADPKD severity with LV mass in a contemporary cohort of ADPKD patients.

Methods

Adults with ADPKD and eGFR> 15 ml/min/1.73m² were enrolled in a single-center study. Left Ventricular Mass (LVM) was quantified using 2D echocardiography, and LVH was defined using gender-specific cut-points of LVM and LVM indexed to body surface area (LVMI) from consensus guidelines. Total Kidney Volume (TKV) was quantified using Magnetic Resonance Imaging, and GFR was estimated from serum creatinine using the CKD-Epi equation. Multiple linear regression was used to estimate the association of TKV and eGFR with LVM and LVMI, adjusting for potential confounders.

Results

Among 126 participants (78% with hypertension), median age was 46 years, median eGFR 63 ml/min/1.73 m2, and median [IQR] systolic blood pressure was 125 [116–133] mmHg. Prevalence of LVH was 21.4% as defined by LVMI and was not significantly different (p = 0.8) between those with and without HTN, and was similar (21.4%) after excluding those (N = 21) with known cardiac disease. Greater TKV and lower eGFR were directly correlated with greater LVMI (p = .016 and p < .001, respectively). In multiple linear regression models accounting for potential confounders including blood pressure, greater TKV was positively associated with LVM (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \hat{\beta} $$\end{document}β^ =0.19, p = 0.04).

Conclusions

In a contemporary cohort of ADPKD patients with well-controlled blood pressure, the prevalence of LVH is high, and ADPKD severity as reflected by TKV is independently associated with greater LV mass. These results may suggest a relationship between ADPKD pathophysiology and increased LV mass.

TRPP2 dysfunction decreases ATP-evoked calcium, induces cell aggregation and stimulates proliferation in T lymphocytes

Background

Autosomal dominant polycystic kidney disease (ADPKD) is mainly characterised by the development and enlargement of renal cysts that lead to end-stage renal disease (ESRD) in adult patients. Other clinical manifestations of this pathology include hypertension, haematuria, abdominal pain, cardiovascular system alterations and intracranial aneurysms. ADPKD is linked to mutations in either PKD1 or PKD2 that codifies polycystin-1 (PC1) and polycystin-2 (PC2 or TRPP2), respectively. PC1 and TRPP2 are membrane proteins that function as receptor-channel elements able to regulate calcium homeostasis. The function of polycystins has been mainly studied in kidney cells; but the role of these proteins in T lymphocytes is not well defined.

Methods

T lymphocytes were produced from ADPKD1 and ADPKD2 patients as well as from non-ADPKD subjects undergoing renal replacement therapy (RRT) and healthy controls. Protein expression and phosphorylation levels were analysed by western blotting, cell proliferation was calculated by direct counting using trypan blue assay and intracellular calcium concentration was measured by Fura-2 method.

Results

PKD2 mutations lead to the significant reduction of TRPP2 expression in T lymphocytes derived from ADPKD patients. Furthermore, a smaller TRPP2 truncated protein in T lymphocytes of patients carrying the mutation R872X in PKD2 was also observed, suggesting that TRPP2 mutated proteins may be stably expressed. The silencing or mutation of PKD2 causes a strong reduction of ATP-evoked calcium in Jurkat cells and ADPKD2 T lymphocytes, respectively. Moreover, T lymphocytes derived from both ADPKD1 and ADPKD2 patients show increased cell proliferation, basal chemotaxis and cell aggregation compared with T lymphocytes from non-ADPKD subjects. Similarly to observations made in kidney cells, mutations in PKD1 and PKD2 dysregulate ERK, mTOR, NFkB and MIF pathways in T lymphocytes.

Conclusions

Because the alteration of ERK, mTOR, NFkB and MIF signalling found in T lymphocytes of ADPKD patients may contribute to the development of interstitial inflammation promoting cyst growth and kidney failure (ESRD), the targeting of inflammasome proteins could be an intriguing option to delay the progression of ADPKD.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1540-6) contains supplementary material, which is available to authorized users.

Polycystin-1 Assembles With Kv Channels to Govern Cardiomyocyte Repolarization and Contractility

BACKGROUND

Polycystin-1 (PC1) is a transmembrane protein originally identified in autosomal dominant polycystic kidney disease where it regulates the calcium-permeant cation channel polycystin-2. Autosomal dominant polycystic kidney disease patients develop renal failure, hypertension, left ventricular hypertrophy, and diastolic dysfunction, among other cardiovascular disorders. These individuals harbor PC1 loss-of-function mutations in their cardiomyocytes, but the functional consequences are unknown. PC1 is ubiquitously expressed, and its experimental ablation in cardiomyocyte-specific knockout mice reduces contractile function. Here, we set out to determine the pathophysiological role of PC1 in cardiomyocytes.

METHODS

Wild-type and cardiomyocyte-specific PC1 knockout mice were analyzed by echocardiography. Excitation-contraction coupling was assessed in isolated cardiomyocytes and human embryonic stem cell-derived cardiomyocytes, and functional consequences were explored in heterologous expression systems. Protein-protein interactions were analyzed biochemically and by means of ab initio calculations.

RESULTS

PC1 ablation reduced action potential duration in cardiomyocytes, decreased Ca²⁺ transients, and myocyte contractility. PC1-deficient cardiomyocytes manifested a reduction in sarcoendoplasmic reticulum Ca²⁺ stores attributable to a reduced action potential duration and sarcoendoplasmic reticulum Ca²⁺ ATPase (SERCA) activity. An increase in outward K⁺ currents decreased action potential duration in cardiomyocytes lacking PC1. Overexpression of full-length PC1 in HEK293 cells significantly reduced the current density of heterologously expressed Kv4.3, Kv1.5 and Kv2.1 potassium channels. PC1 C terminus inhibited Kv4.3 currents to the same degree as full-length PC1. Additionally, PC1 coimmunoprecipitated with Kv4.3, and a modeled PC1 C-terminal structure suggested the existence of 2 docking sites for PC1 within the N terminus of Kv4.3, supporting a physical interaction. Finally, a naturally occurring human mutant PC1^R4228X manifested no suppressive effects on Kv4.3 channel activity.

CONCLUSIONS

Our findings uncover a role for PC1 in regulating multiple Kv channels, governing membrane repolarization and alterations in SERCA activity that reduce cardiomyocyte contractility.

Generation and phenotypic characterization of Pde1a mutant mice

It has been proposed that a reduction in intracellular calcium causes an increase in intracellular cAMP and PKA activity through stimulation of calcium inhibitable adenylyl cyclase 6 and inhibition of phosphodiesterase 1 (PDE1), the main enzymes generating and degrading cAMP in the distal nephron and collecting duct, thus contributing to the development and progression of autosomal dominant polycystic kidney disease (ADPKD). In zebrafish pde1a depletion aggravates and overexpression ameliorates the cystic phenotype. To study the role of PDE1A in a mammalian system, we used a TALEN pair to Pde1a exon 7, targeting the histidine-aspartic acid dipeptide involved in ligating the active site Zn⁺⁺ ion to generate two Pde1a null mouse lines. Pde1a mutants had a mild renal cystic disease and a urine concentrating defect (associated with upregulation of PDE4 activity and decreased protein kinase A dependent phosphorylation of aquaporin-2) on a wild-type genetic background and aggravated renal cystic disease on a Pkd2^WS25/- background. Pde1a mutants additionally had lower aortic blood pressure and increased left ventricular (LV) ejection fraction, without a change in LV mass index, consistent with the high aortic and low cardiac expression of Pde1a in wild-type mice. These results support an important role of PDE1A in the renal pathogenesis of ADPKD and in the regulation of blood pressure.