Long-term Effects of Octreotide on Liver Volume in Patients With Polycystic Kidney and Liver Disease

ACG Clinical Guideline: Focal Liver Lesions

Focal liver lesions (FLLs) have become an increasingly common finding on abdominal imaging, especially asymptomatic and incidental liver lesions. Gastroenterologists and hepatologists often see these patients in consultation and make recommendations for management of multiple types of liver lesions, including hepatocellular adenoma, focal nodular hyperplasia, hemangioma, and hepatic cystic lesions including polycystic liver disease. Malignancy is important to consider in the differential diagnosis of FLLs, and healthcare providers must be familiar with the diagnosis and management of FLLs. This American College of Gastroenterology practice guideline uses the best evidence available to make diagnosis and management recommendations for the most common FLLs.

Investigational agents for autosomal dominant polycystic kidney disease: preclinical and early phase study insights

INTRODUCTION

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inherited kidney condition caused by a single-gene mutation. It leads patients to kidney failure in more than 50% of cases by the age of 60, and, given the dominant inheritance, this disease is present in the family history in more than 90% of cases.

AREAS COVERED

This review aims to analyze the set of preclinical and early-phase studies to provide a general view of the current progress on ADPKD therapeutic options. Articles from PubMed and the current status of the trials listed in clinicaltrials.gov were examined for the review.

EXPERT OPINION

Many potential therapeutic targets are currently under study for the treatment of ADPKD. A few drugs have reached the clinical phase, while many are currently still in the preclinical phase. Organoids could be a novel approach to the study of drugs in this phase. Other than pharmacological options, very important developing approaches are represented by gene therapy and the use of MiRNA inhibitors.

Clinical manifestation, epidemiology, genetic basis, potential molecular targets, and current treatment of polycystic liver disease

Polycystic liver disease (PLD) is a rare condition observed in three genetic diseases, including autosomal dominant polycystic liver disease (ADPLD), autosomal dominant polycystic kidney disease (ADPKD), and autosomal recessive polycystic kidney disease (ARPKD). PLD usually does not impair liver function, and advanced PLD becomes symptomatic when the enlarged liver compresses adjacent organs or increases intra-abdominal pressure. Currently, the diagnosis of PLD is mainly based on imaging, and genetic testing is not required except for complex cases. Besides, genetic testing may help predict patients' prognosis, classify patients for genetic intervention, and conduct early treatment. Although the underlying genetic causes and mechanisms are not fully understood, previous studies refer to primary ciliopathy or impaired ciliogenesis as the main culprit. Primarily, PLD occurs due to defective ciliogenesis and ineffective endoplasmic reticulum quality control. Specifically, loss of function mutations of genes that are directly involved in ciliogenesis, such as Pkd1, Pkd2, Pkhd1, and Dzip1l, can lead to both hepatic and renal cystogenesis in ADPKD and ARPKD. In addition, loss of function mutations of genes that are involved in endoplasmic reticulum quality control and protein folding, trafficking, and maturation, such as PRKCSH, Sec63, ALG8, ALG9, GANAB, and SEC61B, can impair the production and function of polycystin1 (PC1) and polycystin 2 (PC2) or facilitate their degradation and indirectly promote isolated hepatic cystogenesis or concurrent hepatic and renal cystogenesis. Recently, it was shown that mutations of LRP5, which impairs canonical Wnt signaling, can lead to hepatic cystogenesis. PLD is currently treated by somatostatin analogs, percutaneous intervention, surgical fenestration, resection, and liver transplantation. In addition, based on the underlying molecular mechanisms and signaling pathways, several investigational treatments have been used in preclinical studies, some of which have shown promising results. This review discusses the clinical manifestation, complications, prevalence, genetic basis, and treatment of PLD and explains the investigational methods of treatment and future research direction, which can be beneficial for researchers and clinicians interested in PLD.

Questionnaire PLD-complaint-specific assessment identifies need for therapy in polycystic liver disease: A multi-centric prospective study

BACKGROUND AND AIMS

Polycystic liver disease (PLD) can lead to extensive hepatomegaly. Symptom relief is the primary goal of the treatment. The role of the recently developed disease-specific questionnaires for identification of the thresholds and the assessment of therapy needs further investigation.

METHODS

A five-year prospective multi-centric observational study in 21 hospitals in Belgium gathered a study population of 198 symptomatic PLD-patients of whom the disease-specific symptom questionnaire PLD-complaint-specific assessment (POLCA) scores were calculated. The thresholds of the POLCA score for the need for volume reduction therapy were analyzed.

RESULTS

The study group consisted of mostly (82.8%) women with baseline mean age of 54.4 years ±11.2, median liver volume expressed as height-adjusted total liver volume(htLV) of 1994 mL (interquartile range [IQR] 1275; 3150) and median growth of the liver of +74 mL/year (IQR +3; +230). Volume reduction therapy was needed in 71 patients (35.9%). A POLCA severity score (SPI) ≥ 14 predicted the need for therapy both in the derivation (n = 63) and the validation cohort (n = 126). The thresholds to start somatostatin analogues (n = 55) or to consider liver transplantation (n = 18) were SPI scores of ≥14 and ≥ 18 and the corresponding mean htLVs were 2902 mL (IQR 1908; 3964) and 3607 mL (IQR 2901; 4337), respectively. Somatostatin analogues treatment resulted in a decrease in the SPI score -6.0 versus + 4.5 in patients without somatostatin analogues (p < 0.01). Changes in the SPI score were significantly different between the liver transplantation group and no liver transplantation group, +4.3 ± 7.1 versus -1.6 ± 4.9, respectively, (p < 0.01).

CONCLUSION

A polycystic liver disease-specific questionnaire can be used as a guide on when to start a volume reduction therapy and to assess the effect of treatment.

Extrarenal Manifestations: Polycystic Liver Disease and Its Complications

The liver is the commonest site of involvement outside of the kidney in autosomal dominant polycystic kidney disease. Most individuals with polycystic liver disease are asymptomatic and require no therapeutic interventions, but a small number of affected individuals who experience symptomatic polycystic liver disease develop medical complications as a result of massive enlargement of cyst number and size and hepatic parenchyma and its subsequent associated complications. This can lead to deterioration in overall health and quality of life, increasing morbidity and mortality. In this review, we will touch upon disease pathogenesis, prevalence, and complications and discuss recent advances in surgical and medical management.

EASL Clinical Practice Guidelines on the management of cystic liver diseases

The advent of enhanced radiological imaging techniques has facilitated the diagnosis of cystic liver lesions. Concomitantly, the evidence base supporting the management of these diseases has matured over the last decades. As a result, comprehensive clinical guidance on the subject matter is warranted. These Clinical Practice Guidelines cover the diagnosis and management of hepatic cysts, mucinous cystic neoplasms of the liver, biliary hamartomas, polycystic liver disease, Caroli disease, Caroli syndrome, biliary hamartomas and peribiliary cysts. On the basis of in-depth review of the relevant literature we provide recommendations to navigate clinical dilemmas followed by supporting text. The recommendations are graded according to the Oxford Centre for Evidence-Based Medicine system and categorised as 'weak' or 'strong'. We aim to provide the best available evidence to aid the clinical decision-making process in the management of patients with cystic liver disease.

Polycystic Liver Disease: Pathophysiology, Diagnosis and Treatment

Polycystic liver disease (PLD) is a clinical condition characterized by the presence of more than 10 cysts in the liver. It is a rare disease Of genetic etiology that presents as an isolated disease or assoc\iated with polycystic kidney disease. Ductal plate malformation, ciliary dysfunction, and changes in cell signaling are the main factors involved in its pathogenesis. Most patients with PLD are asymptomatic, but in 2–5% of cases the disease has disabling symptoms and a significant reduction in quality of life. The diagnosis is based on family history of hepatic and/or renal polycystic disease, clinical manifestations, patient age, and polycystic liver phenotype shown on imaging examinations. PLD treatment has evolved considerably in the last decades. Somatostatin analogues hold promise in controlling disease progression, but liver transplantation remains a unique curative treatment modality.

Genetics, pathobiology and therapeutic opportunities of polycystic liver disease

Polycystic liver diseases (PLDs) are inherited genetic disorders characterized by progressive development of intrahepatic, fluid-filled biliary cysts (more than ten), which constitute the main cause of morbidity and markedly affect the quality of life. Liver cysts arise in patients with autosomal dominant PLD (ADPLD) or in co-occurrence with renal cysts in patients with autosomal dominant or autosomal recessive polycystic kidney disease (ADPKD and ARPKD, respectively). Hepatic cystogenesis is a heterogeneous process, with several risk factors increasing the odds of developing larger cysts. Depending on the causative gene, PLDs can arise exclusively in the liver or in parallel with renal cysts. Current therapeutic strategies, mainly based on surgical procedures and/or chronic administration of somatostatin analogues, show modest benefits, with liver transplantation as the only potentially curative option. Increasing research has shed light on the genetic landscape of PLDs and consequent cholangiocyte abnormalities, which can pave the way for discovering new targets for therapy and the design of novel potential treatments for patients. Herein, we provide a critical and comprehensive overview of the latest advances in the field of PLDs, mainly focusing on genetics, pathobiology, risk factors and next-generation therapeutic strategies, highlighting future directions in basic, translational and clinical research.

Evidence of nonsurgical treatment for polycystic liver disease

Background:

Polycystic liver disease (PCLD) is the most common extrarenal manifestation of polycystic kidney disease. There is an urgent need to assess the efficacy and safety of nonsurgical modalities to relieve symptoms and decrease the severity of PCLD. Herein, we aimed to evaluate the efficacy of the nonsurgical treatment of PCLD and the quality of life of affected patients.

Methods:

PubMed, Ovid, MEDLINE, EMBASE, and the Cochrane Library were searched for studies on the nonsurgical modalities, either medications or radiological intervention to manage PCLD. Treatment efficacy, adverse events (AEs), and patient quality of life were evaluated.

Results:

In total, 27 studies involving 1037 patients were selected. After nonsurgical treatment, liver volume decreased by 259 ml/m [mean change (Δ) of 6.22%] and the effect was higher in the radiological intervention group [−1617 ml/m (−15.49%)] than in the medication group [−151 ml/m (−3.78%)]. The AEs and serious AEs rates after overall nonsurgical treatment were 0.50 [95% confidence interval (CI): 0.33–0.67] and 0.04 (95% CI: 0.01–0.07), respectively. The results of the SF-36 questionnaire showed that PCLD treatment improved physical function [physical component summary score of 4.18 (95% CI: 1.54–6.83)] but did not significantly improve mental function [mental component summary score of 0.91 (95% CI: −1.20 to 3.03)].

Conclusion:

Nonsurgical treatment was effective and safe for PCLD, but did not improve the quality of life in terms of mental health. Radiological intervention directly reduces hepatic cysts, and thus they should be considered for immediate symptom relief in patients with severe symptoms, whereas medication might be considered for maintenance treatment.

Registration number:

PROSPERO (International Prospective Register of Systematic Reviews) CRD42021279597

Comparative Efficacy of Pharmacological Treatments for Adults With Autosomal Dominant Polycystic Kidney Disease: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background: Tolvaptan is the gold standard treatment for autosomal dominant polycystic kidney disease (ADPKD), while several other drugs have the potential to inhibit the progression of ADPKD. However, individual clinical trials may not show sufficient differences in clinical efficacy due to small sample sizes. Furthermore, the differences in therapeutic efficacy among drugs are unclear. Herein, we investigated the effect of the ADPKD treatments. Methods: We systematically searched PubMed, Medline, EMBASE, and the Cochrane Library through January 2022 to identify randomized controlled trials in ADPKD patients that compared the effects of treatments with placebo or conventional therapy. A network meta-analysis was performed to compare the treatments indirectly. The primary outcomes were changes in kidney function and the rate of total kidney volume (TKV) growth. Results: Sixteen studies were selected with a total of 4,391 patients. Tolvaptan significantly preserved kidney function and inhibited TKV growth compared to the placebo {standardized mean difference (SMD) [95% confidence interval (CI)]: 0.24 (0.16; 0.31) and MD: -2.70 (-3.10; -2.30), respectively}. Tyrosine kinase inhibitors and mammalian target of rapamycin (mTOR) inhibitors inhibited TKV growth compared to the placebo; somatostatin analogs significantly inhibited TKV growth compared to the placebo and tolvaptan [MD: -5.69 (-7.34; -4.03) and MD: -2.99 (-4.69; -1.29), respectively]. Metformin tended to preserve renal function, although it was not significant [SMD: 0.28 (-0.05; 0.61), p = 0.09]. Conclusion: The therapeutic effect of tolvaptan was reasonable as the gold standard for ADPKD treatment, while somatostatin analogs also showed notable efficacy in inhibiting TKV growth. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022300814.

The effects of somatostatin analogues on liver volume and quality of life in polycystic liver disease: a meta-analysis of randomized controlled trials

A clear evidence on the benefits of somatostatin analogues (SA) on liver outcome in patients affected by polycystic liver disease is still lacking. We performed a meta-analysis of RCTs and a trial sequential analysis (TSA) evaluating the effects of SA in adult patients with polycystic liver disease on change in liver volume. As secondary outcome, we evaluated the effects on quality of life as measured by SF36-questionnaire. Six RCTs were selected with an overall sample size of 332 adult patients with polycystic liver disease (mean age: 46 years). Mean liver volume at baseline was 3289 ml in SA group and 3089 ml in placebo group. Overall, unstandardized mean difference in liver volume was - 176 ml (95%CI, - 406, 54; p < 0.133). Heterogeneity was low (I²:0%, p < 0.992). However, we performed a moderator analysis and we found that a higher eGFR significantly correlates to a more pronounced effect of SA on liver volume reduction (p = 0.036). Cumulative Z-curve in TSA did not reach either significance and futility boundaries or required information size. Three RCTs have evaluated Quality of life parameters measured by SF36-QOL questionnaire for a total of 124 patients; no significant difference was found on the effect of SA on QOL parameters when compared with placebo. The present meta-analysis revealed a potential effect of SA on reduction of liver volume and quality of life parameters, but results did not reach a statistical significance. These data could be explained by the need of further studies, as demonstrated through TSA, to reach an adequate sample size to confirm the beneficial outcomes of SAs treatment.

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.

Somatostatin analog therapy effectiveness on the progression of polycystic kidney and liver disease: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Uncertainty underlies the effectiveness of somatostatin analogues for slowing the progression of polycystic kidney or liver disease.

METHODS

Eligible studies included randomized controlled trials (RCTs) evaluating somatostatin analog as therapy for patients with polycystic kidney disease (PKD) or polycystic liver disease (PLD) compared to placebo or standard therapy. Two reviewers independently screened studies identified from databases (MEDLINE, EMBASE, Cochrane Database), clinical trial registries, and references from pertinent articles and clinical practice guidelines. Outcome measurements were changes in total liver volume (TLV), total kidney volume (TKV), and estimated glomerular filtration rate (eGFR).

RESULTS

Of 264 nonduplicate studies screened, 10 RCTs met the inclusion criteria. The body of evidence provided estimates warranting moderate confidence. Meta-analysis of 7 RCTs including a total of 652 patients showed that somatostatin analogs are associated with a lower %TLV growth rate compared to control (mean difference, -6.37%; 95% CI -7.90 to -4.84, p<0.00001), and with a lower %TKV growth rate compared to control (mean difference, -3.66%; 95% CI -5.35 to -1.97, p<0.0001). However, it was not associated with a difference in eGFR decline (mean difference, -0.96 mL/min./1.73m2; 95% CI -2.38 to 0.46, p = 0.19).

CONCLUSIONS

Current body of evidence suggests that somatostatin analogs therapy slows the increase rate of TLV and TKV in patients with PKD or PLD compared to control within a 3-year follow-up period. It does not seem to have an effect on the change in eGFR. Somatostatin analogs therapy can be a promising treatment for ADPKD or ADPLD, and we need to continue to research its effectiveness for ADPKD or ADPLD.

Polycystic liver disease with lethal abdominal wall rupture: a case report

Background

Polycystic liver disease is a clinical feature of autosomal dominant polycystic kidney disease, and it can sometimes cause health damage more serious than polycystic kidney. Dialysis therapy can be used for renal failure, but liver transplantation is the only method available for liver failure. Thus, giant and multiple hepatic cysts may affect mortality. However, liver transplantation is not indicated in many cases because of the preserved liver function.

Case presentation

A 54-year-old Japanese woman with polycystic liver disease was transferred back to our hospital for abdominal pain caused by liver cyst infection with abdominal wall herniation. She had been diagnosed with polycystic liver disease associated with sporadic autosomal dominant polycystic kidney disease 25 years earlier. Although she had several surgical interventions to reduce her liver volume, including right hepatic lobectomy and fenestration for liver cysts in another hospital, she needed further repair of the recurrent incisional herniation with patch graft surgery using fascia lata to cover the herniation site. However, new herniation sites reemerged in the fragile abdominal wall area around the patch, and therefore, she reduced the recurrent abdominal wall herniation by herself. Recurrent intestinal obstructions were luckily released by fasting with decompression treatment via nasogastric tube insertion, but multiple skin ulcers around the enlarged hernia sac gradually developed, and ascites was extremely difficult to control with any medication. At final admission, her abdominal wall was even more prominent, causing shortness of breath, and it spontaneously ruptured many times, which was accompanied by discharge of around 5 liters of ascites each time. She died from sepsis caused by drug-resistant Enterococcus.

Conclusions

We report a case of autosomal dominant polycystic kidney disease with ruptured abdominal wall resulting from a hepatic cyst enlargement despite multiple laparotomy operations. Throughout the entire disease course, her liver volume increased rapidly, and her quality of life was severely impaired, but she could not undergo liver transplantation after readmission to our hospital. We will discuss the therapeutic strategy for this patient, including the timing and indication for liver transplantation.

Therapeutic advances in ADPKD: the future awaits

Autosomal dominant polycystic kidney disease (ADPKD) is a heterogeneous genetic disorder included in ciliopathies, representing the fourth cause of end stage renal disease (ESRD), with an estimated prevalence between 1:1000 and 1:2500. It is mainly caused by mutations in the PKD1 and PKD2 genes encoding for polycystin 1 (PC1) and polycystin 2 (PC2), which regulate differentiation, proliferation, survival, apoptosis, and autophagy. The advances in the knowledge of multiple molecular pathways involved in the pathophysiology of ADPKD led to the development of several treatments which are currently under investigation. Recently, the widespread approval of tolvaptan and, in Italy, of long-acting release octreotide (octreotide-LAR), represents but the beginning of the new therapeutic management of ADPKD patients. Encouraging results are expected from ongoing randomized controlled trials (RCTs), which are investigating not only drugs acting on the calcium/cyclic adenosin monoposphate (cAMP) pathway, the most studied target so far, but also molecules targeting specific pathophysiological pathways (e.g. epidermal growth factor (EGF) receptor, AMP-activated protein kinase (AMPK) and KEAP1-Nrf2) and sphingolipids. Moreover, studies on animal models and cultured cells have also provided further promising therapeutic strategies based on the role of intracellular calcium, cell cycle regulation, MAPK pathway, epigenetic DNA, interstitial inflammation, and cell therapy. Thus, in a near future, tailored therapy could be the key to changing the natural history of ADPKD thanks to the vigorous efforts that are being made to implement clinical and preclinical studies in this field. Our review aimed to summarize the spectrum of drugs that are available in the clinical practice and the most promising molecules undergoing clinical, animal, and cultured cell studies.

Association of a novel PKHD1 mutation in a family with autosomal dominant polycystic liver disease

Background

Autosomal dominant polycystic liver disease (ADPLD) is characterized by multiple cysts in the liver without (or only occasional) renal cysts. At least seven genes are associated with high risk for developing ADPLD; however, clear genetic involvement is undetermined in more than 50% of ADPLD patients.

Methods

To identify additional ADPLD-associated genes, we collected 18 unrelated Chinese ADPLD cases, and performed whole exome sequencing on all the participants. After filtering the sequencing data against the human gene mutation database (HGMD) professional edition, we identified new mutations. We then sequenced this gene in family members of the patient.

Results

Among the 18 ADPLD cases analyzed by whole exome sequencing, we found 2 cases with a PRKCSH mutation (~11.1%), 2 cases with a PKD2 mutation (~11.1%), 1 case with both PKHD1 and PKD1 mutations (~5.6%), 1 case with GANAB mutation (~5.6%), 1 case with PKHD1 mutation (~5.6%), and 1 case with PKD1 mutations (~5.6%). We identified a new PKHD1 missense mutation in an ADPLD family, in which both patients showed innumerable small hepatic cysts, as reported previously. Additionally, we found that PRKCSH and SEC63 mutation frequencies were lower in the Chinese population compared with those in European and American populations.

Conclusions

We report a family with ADPLD associated with a novel PKHD1 mutation (G1210R). The genetic profile of ADPLD in the Chinese population is different from that in European and American populations, suggesting that further genetic research on genetic mutation of ADPLD in the Chinese population is warranted.

COVID-19 and Living Donor Kidney Transplantation in Naples during the Pandemic

Introduction

SARS-CoV-2 is a virus that causes a potentially deadly syndrome that affects especially the respiratory tract. Kidney-transplanted patients are immunosuppressed and more susceptible to viral infections. We have examined our transplantation activity to explore the future role of kidney transplantation from deceased and living donors in COVID-19 era. Patients and Methods. The activity of our transplant center of Naples (one of the two transplant centers in Campania, South Italy) continued during the COVID-19 pandemic. We have analysed the kidney transplants carried out between March 9 and June 9, 2020, comparing these data with the numbers of procedures performed in the two previous years. Moreover, we have considered the possibility of performing living donor transplants during a worldwide pandemic.

Results

From March 9, 2020, when the Italian lockdown begun, till June 9, 2020, five kidney transplants have been performed at our transplant center in Naples, all from deceased donors. The donors and the recipients have been screened for COVID-19 infection, and the patients, all asymptomatic, followed strict preventive measures and were fully informed about the risks of surgery and immunosuppression during a pandemic. All the transplanted patients remained COVID negative during the follow-up. The number of transplants performed has been constant compared to the same months of 2018 and 2019. In agreement with the patients, we decided to postpone living donor transplants to a period of greater control of the SARS-CoV-2 spread in Italy.

Conclusion

Deceased donor kidney transplantation should continue, especially in a region with moderate risk, like Campania, with a more careful selection of donors and recipients, preferring standard donors and recipients without severe comorbidities. Living donor transplantation program, instead, should be postponed to a period of greater control of the SARS-CoV-2 spread, as it is an elective surgery and its delay does not determine additional risks for patients.

Pansomatostatin Agonist Pasireotide Long-Acting Release for Patients with Autosomal Dominant Polycystic Kidney or Liver Disease with Severe Liver Involvement: A Randomized Clinical Trial

BACKGROUND AND OBJECTIVES

We assessed safety and efficacy of another somatostatin receptor analog, pasireotide long-acting release, in severe polycystic liver disease and autosomal dominant polycystic kidney disease. Pasireotide long-acting release, with its broader binding profile and higher affinity to known somatostatin receptors, has potential for greater efficacy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Individuals with severe polycystic liver disease were assigned in a 2:1 ratio in a 1-year, double-blind, randomized trial to receive pasireotide long-acting release or placebo. Primary outcome was change in total liver volume; secondary outcomes were change in total kidney volume, eGFR, and quality of life.

RESULTS

Of 48 subjects randomized, 41 completed total liver volume measurements (n=29 pasireotide long-acting release and n=12 placebo). From baseline, there were -99±189 ml/m absolute and -3%±7% change in annualized change in height-adjusted total liver volume (from 2582±1381 to 2479±1317 ml/m) in the pasireotide long-acting release group compared with 136±117 ml/m absolute and 6%±7% increase (from 2387±759 to 2533±770 ml/m) in placebo (P<0.001 for both). Total kidney volumes decreased by -12±34 ml/m and -1%±4% in pasireotide long-acting release compared with 21±21 ml/m and 4%±5% increase in the placebo group (P=0.05 for both). Changes in eGFR were similar between groups. Among the n=48 randomized, adverse events included hyperglycemia (26 of 33 [79%] in pasireotide long-acting release versus four of 15 [27%] in the placebo group; P<0.001), and among the 47 without diabetes at baseline, 19 of 32 (59%) in the pasireotide long-acting release group versus one of 15 (7%) in the placebo group developed diabetes (P=0.001).

CONCLUSIONS

Another somatostatin analog, pasireotide long-acting release, slowed progressive increase in both total liver volume/total kidney volume growth rates without affecting GFR decline. Participants experienced higher frequency of adverse events (hyperglycemia and diabetes).

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Pasireotide LAR in Severe Polycystic Liver Disease, NCT01670110 PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_08_28_CJN13661119.mp3.

Modulation of polycystic kidney disease by G-protein coupled receptors and cyclic AMP signaling

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disorder associated with polycystic liver disease (PLD) and other extrarenal manifestations, the most common monogenic cause of end-stage kidney disease, and a major burden for public health. Many studies have shown that alterations in G-protein and cAMP signaling play a central role in its pathogenesis. As for many other diseases (35% of all approved drugs target G-protein coupled receptors (GPCRs) or proteins functioning upstream or downstream from GPCRs), treatments targeting GPCR have shown effectiveness in slowing the rate of progression of ADPKD. Tolvaptan, a vasopressin V2 receptor antagonist is the first drug approved by regulatory agencies to treat rapidly progressive ADPKD. Long-acting somatostatin analogs have also been effective in slowing the rates of growth of polycystic kidneys and liver. Although no treatment has so far been able to prevent the development or stop the progression of the disease, these encouraging advances point to G-protein and cAMP signaling as a promising avenue of investigation that may lead to more effective and safe treatments. This will require a better understanding of the relevant GPCRs, G-proteins, cAMP effectors, and of the enzymes and A-kinase anchoring proteins controlling the compartmentalization of cAMP signaling. The purpose of this review is to provide an overview of general GPCR signaling; the function of polycystin-1 (PC1) as a putative atypical adhesion GPCR (aGPCR); the roles of PC1, polycystin-2 (PC2) and the PC1-PC2 complex in the regulation of calcium and cAMP signaling; the cross-talk of calcium and cAMP signaling in PKD; and GPCRs, adenylyl cyclases, cyclic nucleotide phosphodiesterases, and protein kinase A as therapeutic targets in ADPKD.

Physical activity in elderly kidney transplant patients with multiple renal arteries

INTRODUCTION

Kidney transplantation (KT) is the gold standard for treatment of patients with end- stage-renal disease. To expand the donor reserve, it is necessary to use marginal/suboptimal kidneys.

METHODS

We retrospectively evaluated the short/long-term outcome of 34 KT elderly patients who received allografts with vascular abnormalities (MRA group), in comparison with 34 KT patients who received a kidney with a single renal artery (SRA group) pair-matched by age, length of time on dialysis, comorbidity and donor age.

RESULTS

All participants completed the International Physical Activity Questionnaire at KT, and then 4, 8, and 12 weeks after transplantation. Our data indicate that kidney with vascular anatomical variants may be successfully transplanted, since the overall rate of surgical complications was 20.6% in the SRA group and 17.6% in the MRA group and that the 5-year survival rate after KT was 100% in both groups.

CONCLUSIONS

The data also underline that individualized physical activity programs induced similar excellent results in both groups, improving physical capacities, arterial pressure, lipid metabolism, insulin sensitivity, quality of life and physical and mental status.

Relation Between Wound Complication and Lymphocele After Kidney Transplantation: A Monocentric Study

INTRODUCTION

Wound complication frequently arises after kidney transplantation and its risk factors are well known. In a previous paper we analyzed these factors, and in this new retrospective study we evaluate the influence of lymphocele in the development of wound complications.

PATIENTS AND METHODS

From January 2000 to December 2018, 731 consecutive kidney transplants have been performed in our center. We have analyzed the incidence of wound complication and lymphocele and their risk factors.

RESULTS

Out of 731 kidney transplants, we have observed wound complications in 115 patients (15.7%) and lymphocele in 158 patients (21.7%). Of these, 70 patients developed both complications (9.5%), but 6 patients have been excluded because they were in therapy with mammalian target of rapamycin inhibitors. Twenty-nine patients (45.3%) presented a first level and 35 patients (54.7%) showed second level wound complications. Lymphocele was the only present factor in just 3 cases (4.6%). The other patients showed diabetes in 28 cases (43.7%), overweight/obesity in 38 (59.3%), delayed graft function in 17 (26.5%), and 60 years or more in 38 (57.8%). The association has been found in 30 out 64 patients treated with tacrolimus (46.8%) and in 34 with cyclosporine (53.1%); 40 patients did not receive muscular layer's reconstruction (62.5%).

CONCLUSION

Our experience shows that lymphocele alone is not a predisposing factor for wound dehiscence after kidney transplantation, and they often coexist because they share the same risk factors, the most important being obesity, diabetes and delayed graft function, older age, and surgical techniques. No relation has been observed with calcineurin inhibitor therapy.

The Accumulation of Psoralen Contributes to Its Hepatotoxicity Revealed by Pharmacokinetic and Toxicokinetic Study after Repeated Administration

Psoralen is a furanocoumarin compound found in many herb medicines and is claimed to contribute to the hepatotoxicity caused by lots of traditional Chinese medicine. So far, there has been no research on the differences in pharmacokinetics of single and repeated dosing of psoralen. Moreover, the research on the cumulative toxicity of low concentration and long-term administration on cells has not been reported. Therefore, this study investigated the pharmacokinetic differences and the accumulated cytotoxicity of psoralen from repeated administration. The study found that after single or repeated administration of psoralen for 3 months at various dosages (14, 28, and 56 mg/kg), the pharmacokinetic parameters of female rats between single dose and repeated dose administration are totally different. Compared with a single administration, multiple administrations increased psoralen's in vivo exposure, prolonged the peak time, prolonged the half-life of the drug, reduced the drug clearance rate, and prolonged the drug's stay in the body. HepG2 cells were exposed to low doses (5, 10, 20, or 40 μM) of psoralen for 1, 2, 3, or 4 days. A 20 and 40 μM dose of psoralen did not induced cell death in the 1st day but significantly decreased the cell viability at the 3rd and 4th day of repeated administration, respectively. In addition, multiple administrations of psoralen decreased cell viability due to G2 arrest.

Long-acting somatostatin analogue treatments in autosomal dominant polycystic kidney disease and polycystic liver disease: a systematic review and meta-analysis

OBJECTIVES

A number of randomised control trials (RCTs) investigating the effects of long-acting somatostatin analogues in autosomal dominant polycystic kidney disease (ADPKD) and polycystic liver disease (PLD) have been recently reported. We sought to evaluate all available RCTs investigating the efficacy of somatostatin analogues treatment in ADPKD and PLD.

DATA SOURCES

Electronic databases; Pubmed, Clincaltrials.gov and Cochrane Central Register of Controlled Trials ELIGIBILITY CRITERIA FOR SELECTING STUDIES: RCTs and randomised cross-over trials comparing the effects of somatostatin analogue treatment with controls in patients with ADPKD or PLD.

DATA EXTRACTION AND SYNTHESIS

Data extraction and bias assessments were performed by two independent reviewers between January and May 2019. Outcomes assessed included estimated glomerular filtration rate (eGFR), total kidney volume (TKV), total liver volume (TLV), progression to end stage renal failure (ESRF) and adverse effects. Data were pooled using a random-effects model and reported as relative risk or mean difference with 95% CIs.

RESULTS

Meta-analysis was performed of six RCTs or randomised cross-over trials and three secondary analyses. A total of 592 patients were included. Compared with controls, somatostatin analogue treatment significantly reduced TLV (mean difference -0.15 L, 95% CI -0.26 to -0.03, p=0.01). There was no significant effect on TKV (mean difference -0.19 L, 95% CI -0.50 to 0.12, p=0.23) or eGFR (mean difference 0.27 mL/min/1.73 m², 95% CI -2.03 to 2.57, p=0.82). There was no effect on progression to ESRF. Somatostatin analogues were associated with known adverse effects such as gastrointestinal symptoms.

CONCLUSIONS

The available RCT data show improvement in TLV with somatostatin analogue treatment. There was no benefit to TKV or eGFR in patients with ADPKD, while being associated with various side effects. Further studies are needed to assess potential benefit in reducing cyst burden in patients with PLD.

Targeted Therapies for Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening genetic disease in humans, affecting approximately 1 in 500 people. ADPKD is characterized by cyst growth in the kidney leading to progressive parenchymal damage and is the underlying pathology in approximately 10% of patients requiring hemodialysis or transplantation for end-stage kidney disease. The two proteins that are mutated in ADPKD, polycystin-1 and polycystin-2, form a complex located on the primary cilium and the plasma membrane to facilitate calcium ion release in the cell. There is currently no Food and Drug Administration (FDA)-approved therapy to cure or slow the progression of the disease. Rodent ADPKD models do not completely mimic the human disease, and therefore preclinical results have not always successfully translated to the clinic. Moreover, the toxicity of many of these potential therapies has led to patient withdrawals from clinical trials.

RESULTS

Here, we review compounds in clinical trial for treating ADPKD, and we examine the feasibility of using a kidney-targeted approach, with potential for broadening the therapeutic window, decreasing treatment-associated toxicity and increasing the efficacy of agents that have demonstrated activity in animal models. We make recommendations for integrating kidney- targeted therapies with current treatment regimes, to achieve a combined approach to treating ADPKD.

CONCLUSION

Many compounds are currently in clinical trial for ADPKD yet, to date, none are FDA-approved for treating this disease. Patients could benefit from efficacious pharmacotherapy, especially if it can be kidney-targeted, and intensive efforts continue to be focused on this goal.

Lanreotide Reduces Liver Growth In Patients With Autosomal Dominant Polycystic Liver and Kidney Disease

BACKGROUND & AIMS

Polycystic liver disease is the most common extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). There is need for robust long-term evidence for the volume-reducing effect of somatostatin analogues. We made use of data from an open-label, randomized trial to determine the effects of lanreotide on height-adjusted liver volume (hTLV) and combined height-adjusted liver and kidney volume (hTLKV) in patients with ADPKD.

METHODS

We performed a 120-week study comparing the reno-protective effects of lanreotide vs standard care in 305 patients with ADPKD (the DIPAK-1 study). For this analysis, we studied the 175 patients with polycystic liver disease with hepatic cysts identified by magnetic resonance imaging and liver volume ≥2000 mL. Of these, 93 patients were assigned to a group that received lanreotide (120 mg subcutaneously every 4 weeks) and 82 to a group that received standard care (blood pressure control, a sodium-restricted diet, and antihypertensive agents). The primary endpoint was percent change in hTLV between baseline and end of treatment (week 120). A secondary endpoint was change in hTLKV.

RESULTS

At 120 weeks, hTLV decreased by 1.99% in the lanreotide group (95% confidence interval [CI], -4.21 to 0.24) and increased by 3.92% in the control group (95% CI, 1.56-6.28). Compared with the control group, lanreotide reduced the growth of hTLV by 5.91% (95% CI, -9.18 to -2.63; P < .001). Growth of hTLV was still reduced by 3.87% at 4 months after the last injection of lanreotide compared with baseline (95% CI, -7.55 to -0.18; P = .04). Lanreotide reduced growth of hTLKV by 7.18% compared with the control group (95% CI, -10.25 to -4.12; P < .001).

CONCLUSIONS

In this subanalysis of a randomized trial of patients with polycystic liver disease due to ADPKD, lanreotide for 120 weeks reduced the growth of liver and combined liver and kidney volume. This effect was still present 4 months after the last injection of lanreotide. ClinicalTrials.gov, Number: NCT01616927.

Octreotide-LAR in later-stage autosomal dominant polycystic kidney disease (ALADIN 2): A randomized, double-blind, placebo-controlled, multicenter trial

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent genetically determined renal disease. In affected patients, renal function may progressively decline up to end-stage renal disease (ESRD), and approximately 10% of those with ESRD are affected by ADPKD. The somatostatin analog octreotide long-acting release (octreotide-LAR) slows renal function deterioration in patients in early stages of the disease. We evaluated the renoprotective effect of octreotide-LAR in ADPKD patients at high risk of ESRD because of later-stage ADPKD.

METHODS AND FINDINGS

We did an internally funded, parallel-group, double-blind, placebo-controlled phase III trial to assess octreotide-LAR in adults with ADPKD with glomerular filtration rate (GFR) 15-40 ml/min/1.73 m2. Participants were randomized to receive 2 intramuscular injections of 20 mg octreotide-LAR (n = 51) or 0.9% sodium chloride solution (placebo; n = 49) every 28 days for 3 years. Central randomization was 1:1 using a computerized list stratified by center and presence or absence of diabetes or proteinuria. Co-primary short- and long-term outcomes were 1-year total kidney volume (TKV) (computed tomography scan) growth and 3-year GFR (iohexol plasma clearance) decline. Analyses were by modified intention-to-treat. Patients were recruited from 4 Italian nephrology units between October 11, 2011, and March 20, 2014, and followed up to April 14, 2017. Baseline characteristics were similar between groups. Compared to placebo, octreotide-LAR reduced median (95% CI) TKV growth from baseline by 96.8 (10.8 to 182.7) ml at 1 year (p = 0.027) and 422.6 (150.3 to 695.0) ml at 3 years (p = 0.002). Reduction in the median (95% CI) rate of GFR decline (0.56 [-0.63 to 1.75] ml/min/1.73 m2 per year) was not significant (p = 0.295). TKV analyses were adjusted for age, sex, and baseline TKV. Over a median (IQR) 36 (24 to 37) months of follow-up, 9 patients on octreotide-LAR and 21 patients on placebo progressed to a doubling of serum creatinine or ESRD (composite endpoint) (hazard ratio [HR] [95% CI] adjusted for age, sex, baseline serum creatinine, and baseline TKV: 0.307 [0.127 to 0.742], p = 0.009). One composite endpoint was prevented for every 4 treated patients. Among 63 patients with chronic kidney disease (CKD) stage 4, 3 on octreotide-LAR and 8 on placebo progressed to ESRD (adjusted HR [95% CI]: 0.121 [0.017 to 0.866], p = 0.036). Three patients on placebo had a serious renal cyst rupture/infection and 1 patient had a serious urinary tract infection/obstruction, versus 1 patient on octreotide-LAR with a serious renal cyst infection. The main study limitation was the small sample size.

CONCLUSIONS

In this study we observed that in later-stage ADPKD, octreotide-LAR slowed kidney growth and delayed progression to ESRD, in particular in CKD stage 4.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01377246; EudraCT: 2011-000138-12.

Genetics of polycystic liver diseases

PURPOSE OF REVIEW

This review provides an outline of the most recent insights and significant discoveries regarding the genetic mechanisms involved in polycystic liver disease.

RECENT FINDINGS

Polycystic liver disease includes a heterogeneous group of genetic disorders characterized by multiple hepatic cysts. Isolated liver cysts are caused by mutations in Protein Kinase C Substrate 80K-H (PRKCSH), SEC63, and LDL Receptor Related Protein 5 (LRP5), whereas Polycystic Kidney Disease (PKD)1, PKD2, and PKHD1 mutations cause kidney cysts often accompanied by liver cysts. Glucosidase II Alpha Subunit (GANAB) has been reported to cause both phenotypes. These mutations, together with the newly identified ones in SEC61B and Alpha-1,3-Glucosyltransferase (ALG8), can be found in ∼50% of patients with isolated polycystic liver disease. Somatic second hit-mutations are hypothesized as driving force leading to cystogenesis. Subsequently, loss of heterozygosity in the cystic tissue aggravates disease progression. All genetic mutations lead to reduced levels of functional polycystin-1. This ciliary protein is therefore considered to be the central factor in the development and severity of liver cysts.

SUMMARY

Recent advances of the genetic complexity leading to hepatic cystogenesis provide novel candidate genes and important mechanistic insights with polycystin-1 as a common denominator.

Unmet needs and challenges for follow-up and treatment of autosomal dominant polycystic kidney disease: the paediatric perspective

Awareness is growing that the clinical course of autosomal dominant polycystic kidney disease (ADPKD) already begins in childhood, with a broad range of both symptomatic and asymptomatic features. Knowing that parenchymal destruction with cyst formation and growth starts early in life, it seems reasonable to assume that early intervention may yield the best chances for preserving renal outcome. Interventions may involve lifestyle modifications, hypertension control and the use of disease-modifying treatments once these become available for the paediatric population with an acceptable risk and side-effect profile. Until then, screening of at-risk children is controversial and not generally recommended since this might cause psychosocial and financial harm. Also, the clinical and research communities are facing important questions as to the nature of potential interventions and their optimal indications and timing. Indeed, challenges include the identification and validation of indicators, both measuring and predicting disease progression from childhood, and the discrimination of slow from rapid progressors in the paediatric population. This discrimination will improve both the cost-effectiveness and benefit-to-risk ratio of therapies. Furthermore, we will need to define outcome measures, and to evaluate the possibility of a potential therapeutic window of opportunity in childhood. The recently established international register ADPedKD will help in elucidating these questions. In this review, we provide an overview of the current knowledge on paediatric ADPKD as a future therapeutic target population and its unmet challenges.

Drug holiday in patients with polycystic liver disease treated with somatostatin analogues

BACKGROUND

Somatostatin analogues (SAs) reduce liver volume and relief symptoms in polycystic liver disease (PLD). Its effect wears off after continuing therapy suggesting development of SA tolerance in patients on chronic therapy. We postulate that a drug holiday resensitizes the liver to its acute pharmacological effects. Therefore, this study examines the liver volume-reducing effect of SAs after a drug holiday.

METHODS

Patients were identified from the International PLD Registry and included in our analysis when (1) treated with SAs during two cycles separated by a drug holiday and (2) height-adjusted total liver volume (hTLV) was available at start and end of each cycle. For our primary outcome we compared the effect of SAs (in % per 6 months) on hTLV between the first and second treatment cycle.

RESULTS

In 34 patients, initial liver volume-reducing effect was similar to that after rechallenge [-2.6% per 6 months (interquartile range, -3.8-0.8) versus -1.6% per 6 months (interquartile range, -3.1-1.1), p = 0.510]. Cessation of treatment led to a rebound effect, but liver volume remained stable compared with the baseline with intermittent therapy in responders to SA [-0.6% (interquartile range, -7.4-5.7) after 46.5 months].

CONCLUSIONS

PLD patients treated with SAs benefit from retreatment after a drug holiday. The significant increase of liver volume after cessation of treatment complicates widespread use of a drug holiday as new treatment strategy. Our results contribute to a better understanding of the pharmacological effect of SAs and help to identify patients who might benefit.

Biliary Tract and Liver Complications in Polycystic Kidney Disease

Polycystic liver disease is a well described manifestation of autosomal dominant polycystic kidney disease (ADPKD). Biliary tract complications are less well recognized. We report a 50-year single-center experience of 1007 patients, which raised a hypothesis that ADPKD is associated with biliary tract disease. We tested this hypothesis using all England Hospital Episode Statistics data (1998-2012), within which we identified 23,454 people with ADPKD and 6,412,754 hospital controls. Hospitalization rates for biliary tract disease, serious liver complications, and a range of other known ADPKD manifestations were adjusted for potential confounders. Compared with non-ADPKD hospital controls, those with ADPKD had higher rates of admission for biliary tract disease (rate ratio [RR], 2.24; 95% confidence interval [95% CI], 2.16 to 2.33) and serious liver complications (RR, 4.67; 95% CI, 4.35 to 5.02). In analyses restricted to those on maintenance dialysis or with a kidney transplant, RRs attenuated substantially, but ADPKD remained associated with biliary tract disease (RR, 1.19; 95% CI, 1.08 to 1.31) and perhaps with serious liver complications (RR, 1.15; 95% CI, 0.98 to 1.33). The ADPKD versus non-ADPKD RRs for biliary tract disease were larger for men than women (heterogeneity P<0.001), but RRs for serious liver complications appeared higher in women (heterogeneity P<0.001). Absolute excess risk of biliary tract disease associated with ADPKD was larger than that for serious liver disease, cerebral aneurysms, and inguinal hernias but less than that for urinary tract infections. Overall, biliary tract disease seems to be a distinct and important extrarenal complication of ADPKD.

Comparison of MRI segmentation techniques for measuring liver cyst volumes in autosomal dominant polycystic kidney disease

PURPOSE

To compare MRI segmentation methods for measuring liver cyst volumes in autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Liver cyst volumes in 42 ADPKD patients were measured using region growing, thresholding and cyst diameter techniques. Manual segmentation was the reference standard.

RESULTS

Root mean square deviation was 113, 155, and 500 for cyst diameter, thresholding and region growing respectively. Thresholding error for cyst volumes below 500ml was 550% vs 17% for cyst volumes above 500ml (p<0.001).

CONCLUSION

For measuring volume of a small number of cysts, cyst diameter and manual segmentation methods are recommended. For severe disease with numerous, large hepatic cysts, thresholding is an acceptable alternative.

An update on the pathophysiology and management of polycystic liver disease

Polycystic liver disease (PLD) is characterized by the presence of multiple cholangiocyte-derived hepatic cysts that progressively replace liver tissue. They are classified as an inherited ciliopathy /cholangiopathy as pathology exists at the level of the primary cilia of cholangiocytes. Aberrant expression of the proteins in primary cilia can impair their structures and functions, thereby promoting cystogenesis. Areas covered: This review begins by looking at the epidemiology of PLD and its natural history. It then describes the pathophysiology and corresponding potential treatment strategies for PLD. Expert commentary: Traditionally, therapies for symptomatic PLD have been limited to symptomatic management and surgical interventions. Such techniques are not completely effective, do not alter the natural history of the disease, and are linked with high rate of re-accumulation of cysts. As a result, there has been a push for drugs targeted at abnormal cellular signaling cascades to address deregulated proliferation, cell dedifferentiation, apoptosis and fluid secretion. Currently, the only available drug treatments that halt disease progression and improve quality of life in PLD patients are somatostatin analogues. Numerous preclinical studies suggest that targeting components of the signaling pathways that influence cyst development can ameliorate growth of hepatic cysts.

Clinical Trials in Pediatric Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and is associated with concerning long-term implications for kidney function and cardiovascular health. Early intervention is needed in order to mitigate these long-term complications. Herein, we review important findings from recent clinical trials in ADPKD and their relevance to affected children and young adults and consider future directions for intervention. Recent clinical trials support aggressive control of blood pressure with blockade of the renin-angiotensin-aldosterone system as well as potential benefit of pravastatin therapy in children and young adults with ADPKD. There are several other candidate therapies, some of which have shown benefit in adult ADPKD, which require further investigation in affected children.

Clinical Manifestation and Management of ADPKD in Western Countries

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease in Western countries. The prevalence is between 2.4/10,000 and 3.9/10,000. ADPKD represents a systemic disease resulting in deterioration in renal function. Until now, mutations in two genes (PKD1 and PKD2) have been identified. Recently, the European Medicines Agency (EMA) approved the use of the vasopressin V2 receptor antagonist tolvaptan to slow the progression of cyst development and renal insufficiency connected with ADPKD in adult patients with chronic kidney disease stages 1-3 at initiation of treatment with evidence of rapidly progressing disease. Whereas the EMA approved the release of tolvaptan, the US Food and Drug Administration (FDA) requested further data on side effects and the selection of patient cohorts who may benefit from treatment.

SUMMARY

This review focused on advances in the management and treatment of ADPKD in Western countries.

KEY MESSAGE

ADPKD represents the fourth most common cause of end-stage renal disease (ESRD) in Western countries. ADPKD is a multisystemic disease characterized by the progressive development of bilateral renal cysts, resulting in enlargement of the kidney volume due to cystic formations, hypertension, hematuria, and loss of renal function. ADPKD is associated with high inter- and intrafamilial variability in disease appearance and progression. Patients with PKD1 mutations typically have a more severe phenotype than those with PKD2 mutations. ADPKD is under intensive investigation. Vasopressin and the associated cyclic adenosine monophosphate-related signaling pathways have been demonstrated to be important contributors to cyst growth in ADPKD. Supportive treatments are recommended with the aim of reducing morbidity and mortality associated with disease manifestations. In the past years, several agents have been investigated in ADPKD patients, including mTOR inhibitors, somatostatin analogs, statins, and vasopressin V2 receptor antagonists.

FACTS FROM EAST AND WEST

(1) ADPKD is diagnosed globally by ultrasound detection of kidney enlargement and presence of cysts. Recent analyses of variants of the PKD1 and PKD2 genes by next-generation sequencing in Chinese and Western ADPKD patients might lead to the development of reliable genetic tests. (2) Besides lifestyle changes (low-salt diet, sufficient fluid intake, and no smoking), blood pressure control is the primary nonspecific treatment recommended by Kidney Disease - Improving Global Outcomes (KDIGO) for ADPKD patients. How low the blood pressure target should be and what the means of achieving it are remain open questions depending on the severity of chronic kidney disease and the age of the patients. In a recent Chinese study, diagnostic needle aspiration and laparoscopic unroofing surgery successfully improved infection, pain, and hypertension. Peritoneal dialysis was found to be a feasible treatment for most Chinese ADPKD patients with ESRD. In most Western centers, patients without contraindication are selected for peritoneal dialysis. Kidney transplantation with concurrent bilateral nephrectomy was successful in relieving hypertension and infection in Chinese ADPKD patients. In Western countries, sequential surgical intervention with kidney transplantation after nephrectomy, or the other way round, is preferred in order to reduce risks. (3) The vasopressin 2 receptor antagonist tolvaptan was approved in Europe, Canada, Japan, and Korea to slow down progression of kidney disease in ADPKD patients. Tolvaptan is not yet approved in the USA or in China. mTOR pathway-targeting drugs are currently under evaluation: mTOR inhibitors could slow down the increase in total kidney volume in a cohort of Western and Japanese ADPKD patients. Western studies as well as an ongoing study in China failed to show benefit from rapamycin. A study performed in Italy indicates protective effects of the somatostatin analog octreotide in ADPKD patients. Western and Chinese studies revealed a potential beneficial effect of triptolide, the active substance of the traditional Chinese medicine Tripterygium wilfordii (Lei Gong Teng) to prevent worsening in ADPKD patients.