Ursodeoxycholic acid in advanced polycystic liver disease: A phase 2 multicenter randomized controlled trial

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.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Higher need for polycystic liver disease therapy in female patients: Sex-specific association between liver volume and need for therapy

BACKGROUND AND AIMS

Prognostic tools or biomarkers are urgently needed in polycystic liver disease (PLD) to monitor disease progression and evaluate treatment outcomes. Total liver volume (TLV) is currently used to assess cross-sectional disease severity, and female patients typically have larger livers than males. Therefore, this study explores the sex-specific association between TLV and volume-reducing therapy (VRT).

APPROACH AND RESULTS

In this prospective cohort study, we included patients with PLD from European treatment centers. We explored sex-specific differences in the association between baseline TLV and initiation of volume-reducing therapy and determined the cumulative incidence rates of volume-reducing therapy in our cohort.We included 358 patients, of whom 157 (43.9%) received treatment. Treated patients had a higher baseline TLV (median TLV 2.16 vs. 4.34 liter, p < 0.001), were more frequently female (69.7% vs. 89.8%, p < 0.001), and had a higher risk of liver events (HR 4.381, p < 0.001). The cumulative volume-reducing therapy rate at 1 year of follow-up was 21.0% for females compared to 9.1% for males. Baseline TLV was associated with volume-reducing therapy, and there was an interaction with sex (HR females 1.202, p < 0.001; HR males 1.790, p < 0.001; at 1.5 l).

CONCLUSION

Baseline TLV is strongly associated with volume-reducing therapy initiation at follow-up in patients with PLD, with sex-specific differences in this association. Disease staging systems should use TLV to predict the need for future volume-reducing therapy in PLD separately for males and females.

Polycystic liver diseases: from molecular basis to development of effective treatments

Polycystic liver diseases (PLDs) comprise a heterogeneous group of congenital genetic disorders that mainly affect bile duct epithelial cells, known as cholangiocytes. Patients with PLD usually present bile duct dilatation and/or progressive develop intrahepatic, fluid-filled biliary cysts (more than 10), which is the main cause of morbidity.

Liver transplantation for polycystic liver disease: a case report

A 57-year-old man complained about abdominal distension and pain, constant feeling of early satiety. He was diagnosed with polycystic kidneys at the age of 24 and liver cysts discovered at the age of 38. The CT scan revealed 33 x 21 x 27 cm polycystic liver with cysts up to 7 cm in diameter. In 2009-2019 the patient was repeatedly punctured for liver cysts. Considering the continued enlargement of the liver and the worsening of complaints, the patient was put on the waiting list for a liver transplant in the spring of 2019. The patient went through liver transplantation on 11th of July 2022, the liver measures were 53 x 37 x 39 x 16 cm and weight 14,75 kg. The postoperative course was uneventful. Liver transplantation can be very effective treatment method that significantly improves the quality of life in PLD patients.

Multi-omics profiling of cholangiocytes reveals sex-specific chromatin state dynamics during hepatic cystogenesis in polycystic liver disease

BACKGROUND & AIMS

Cholangiocytes transit from quiescence to hyperproliferation during cystogenesis in polycystic liver disease (PLD), the severity of which displays prominent sex differences. Epigenetic regulation plays important roles in cell state transition. We aimed to investigate the sex-specific epigenetic basis of hepatic cystogenesis and to develop therapeutic strategies targeting epigenetic modifications for PLD treatment.

METHODS

Normal and cystic primary cholangiocytes were isolated from wild-type and PLD mice of both sexes. Chromatin states were characterized by analyzing chromatin accessibility (ATAC sequencing) and multiple histone modifications (chromatin immunoprecipitation sequencing). Differential gene expression was determined by transcriptomic analysis (RNA sequencing). Pharmacologic inhibition of epigenetic modifying enzymes was undertaken in PLD model mice.

RESULTS

Through genome-wide profiling of chromatin dynamics, we revealed a profound increase of global chromatin accessibility during cystogenesis in both male and female PLD cholangiocytes. We identified a switch from H3K9me3 to H3K9ac on cis-regulatory DNA elements of cyst-associated genes and showed that inhibition of H3K9ac acetyltransferase or H3K9me3 demethylase slowed cyst growth in male, but not female, PLD mice. In contrast, we found that H3K27ac was specifically increased in female PLD mice and that genes associated with H3K27ac-gained regions were enriched for cyst-related pathways. In an integrated epigenomic and transcriptomic analysis, we identified an estrogen receptor alpha-centered transcription factor network associated with the H3K27ac-regulated cystogenic gene expression program in female PLD mice.

CONCLUSIONS

Our findings highlight the multi-layered sex-specific epigenetic dynamics underlying cholangiocyte state transition and reveal a potential epigenetic therapeutic strategy for male PLD patients.

IMPACT AND IMPLICATIONS

In the present study, we elucidate a sex-specific epigenetic mechanism underlying the cholangiocyte state transition during hepatic cystogenesis and identify epigenetic drugs that effectively slow cyst growth in male PLD mice. These findings underscore the importance of sex difference in the pathogenesis of PLD and may guide researchers and physicians to develop sex-specific personalized approaches for PLD treatment.

Treatment of Polycystic Liver Disease: Impact on Patient-reported Symptom Severity and Health-related Quality of Life

Polycystic liver disease (PLD) is a genetic disorder in which patients suffer from progressive development of multiple (>10) hepatic cysts. Most patients remain asymptomatic during the course of their disease. However, a minority of PLD patients suffer from symptoms caused by hepatomegaly leading to serious limitations in daily life. Untreated symptomatic PLD patients score significantly worse on health-related quality of life (HRQoL) compared to age and gender-matched populations. Currently, liver transplantation is the only curative treatment for PLD. The main goal of other available therapies is to strive for symptomatic relief and improvement of HRQoL by suppressing disease progression. In this review, we summarize the effect of PLD treatment on patient-reported outcome measures with a distinction between HRQoL and symptom severity. At present there is heterogeneity in application of questionnaires and no questionnaire is available that measures both HRQoL and PLD symptom severity. Therefore, we recommend the combination of a validated PLD-specific symptom severity questionnaire and a general HRQoL questionnaire to evaluate treatment success as a minimal core set. However, the specific choice of questionnaires depends on treatment choice and/or research question. These questionnaires may serve as a biomarker of treatment response, failure, and adverse events.

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

Comparison of the Efficacy and Safety of Single-Session OK-432 and Multiple-Session 99% Ethanol Sclerotherapy for Symptomatic Simple Hepatic Cysts

Purpose

This retrospective study aimed to compare the efficacy and safety of single-session OK-432 and multiple-session 99% ethanol sclerotherapy for symptomatic simple hepatic cysts.

Methods

We reviewed patients who received aspiration sclerotherapy with OK-432 (group A) or 99% ethanol (group B) for symptomatic simple hepatic cysts at Guangdong Provincial People's Hospital from January 2013 to November 2019.

Results

We included 42 patients in group A and 39 patients in group B. No significant difference was found in the mean volume of hepatic cysts between the two groups. The overall success rates were 92.9% (39 of 42 patients) in group A and 79.5% (31 of 39 patients) in group B (P = 0.08). The treatment success for cyst volumes &lt;200 ml, 200–500 ml, and &gt;500 ml was 100, 93.3, and 88.2% in group A, and 100, 84.6, and 57.1% in group B, respectively. The symptomatic relief rate in group A was higher than that in group B for cysts ≥500 ml (P = 0.049) and cysts &lt;500 ml. For treatment-related complications, the incidence of pain at the injection site in group A was lower than that in group B.

Conclusion

Single-session OK-432 sclerotherapy was safer and more effective than multiple-session 99% ethanol sclerotherapy for treating large cysts, although both treatments had similar effects on small cysts.

Tauroursodeoxycholic acid: a potential therapeutic tool in neurodegenerative diseases

Most neurodegenerative disorders are diseases of protein homeostasis, with misfolded aggregates accumulating. The neurodegenerative process is mediated by numerous metabolic pathways, most of which lead to apoptosis. In recent years, hydrophilic bile acids, particularly tauroursodeoxycholic acid (TUDCA), have shown important anti-apoptotic and neuroprotective activities, with numerous experimental and clinical evidence suggesting their possible therapeutic use as disease-modifiers in neurodegenerative diseases. Experimental evidence on the mechanisms underlying TUDCA's neuroprotective action derives from animal models of Alzheimer's disease, Parkinson's disease, Huntington's diseases, amyotrophic lateral sclerosis (ALS) and cerebral ischemia. Preclinical studies indicate that TUDCA exerts its effects not only by regulating and inhibiting the apoptotic cascade, but also by reducing oxidative stress, protecting the mitochondria, producing an anti-neuroinflammatory action, and acting as a chemical chaperone to maintain the stability and correct folding of proteins. Furthermore, data from phase II clinical trials have shown TUDCA to be safe and a potential disease-modifier in ALS. ALS is the first neurodegenerative disease being treated with hydrophilic bile acids. While further clinical evidence is being accumulated for the other diseases, TUDCA stands as a promising treatment for neurodegenerative diseases.

Polycystic Kidney/Liver Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder that leads to chronic kidney disease and end-stage kidney disease (ESKD). Polycystic liver disease (PCLD) is the most common extrarenal manifestation of ADPKD. Though isolated PCLD and PCLD due to ADPKD are genetically distinct, they follow a similar clinical course of hepatomegaly from multiple cysts with preserved liver function. Tolvaptan use in ADPKD can slow down the deterioration of renal function and growth of cysts. Somatostatin analogs can slow the growth of polycystic livers but the effect is short-lived. The only curative therapy for PCLD is liver transplantation. Renal transplantation can significantly improve survival in patients with ESKD due to ADPKD.

Polycystic liver: automatic segmentation using deep learning on CT is faster and as accurate compared to manual segmentation

OBJECTIVE

This study aimed to develop and investigate the performance of a deep learning model based on a convolutional neural network (CNN) for the automatic segmentation of polycystic livers at CT imaging.

METHOD

This retrospective study used CT images of polycystic livers. To develop the CNN, supervised training and validation phases were performed using 190 CT series. To assess performance, the test phase was performed using 41 CT series. Manual segmentation by an expert radiologist (Rad1a) served as reference for all comparisons. Intra-observer variability was determined by the same reader after 12 weeks (Rad1b), and inter-observer variability by a second reader (Rad2). The Dice similarity coefficient (DSC) evaluated overlap between segmentations. CNN performance was assessed using the concordance correlation coefficient (CCC) and the two-by-two difference between the CCCs; their confidence interval was estimated with bootstrap and Bland-Altman analyses. Liver segmentation time was automatically recorded for each method.

RESULTS

A total of 231 series from 129 CT examinations on 88 consecutive patients were collected. For the CNN, the DSC was 0.95 ± 0.03 and volume analyses yielded a CCC of 0.995 compared with reference. No statistical difference was observed in the CCC between CNN automatic segmentation and manual segmentations performed to evaluate inter-observer and intra-observer variability. While manual segmentation required 22.4 ± 10.4 min, central and graphics processing units took an average of 5.0 ± 2.1 s and 2.0 ± 1.4 s, respectively.

CONCLUSION

Compared with manual segmentation, automated segmentation of polycystic livers using a deep learning method achieved much faster segmentation with similar performance.

KEY POINTS

• Automatic volumetry of polycystic livers using artificial intelligence method allows much faster segmentation than expert manual segmentation with similar performance. • No statistical difference was observed between automatic segmentation, inter-observer variability, or intra-observer variability.

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.

Establishing a core outcome measure for pain in patients with autosomal dominant polycystic kidney disease: a consensus workshop report

Background

Pain is the highest prioritized patient-reported outcome in people with autosomal dominant polycystic kidney disease (ADPKD) but remains infrequently and inconsistently measured in clinical trials and poorly managed in clinical settings. A recently completed systematic review of pain in ADPKD identified 26 different outcome measures. None of these measures were considered appropriate as a core outcome measure due to the lack of patient-important dimensions, inadequate content, relatively long duration of completion time and limited evidence to support psychometric robustness.

Methods

We convened an international Standardized Outcomes in Nephrology–Polycystic Kidney Disease consensus workshop involving 21 patients/caregivers and 40 health professionals (clinicians, nurses, researchers, policy makers and industry representatives) from 18 countries to discuss the identification or development of a core outcome measure for pain.

Results

Four themes were identified highlighting fundamental issues for the measurement of pain in ADPKD: distressing and disrupting life participation; variability and ambiguity in defining pain; stigma, frustration and adaptation to pain; and ensuring validity and feasibility of pain measures.

Conclusions

Existing measures were found to be insufficient in capturing pain as a core outcome and there was consensus on the need for a new validated measure that is simple, succinct and addresses the impact of pain on life participation. This measure will facilitate the appropriate prioritization of pain in all trials and guide clinical decision making in people with ADPKD.

Patient-reported outcome measures for pain in autosomal dominant polycystic kidney disease: A systematic review

Pain is a common symptom in people with autosomal dominant polycystic kidney disease (ADPKD), but it is assessed and reported inconsistently in research, and the validity of the measures remain uncertain. The aim of this study was to identify the characteristics, content, and psychometric properties of measures for pain used in ADPKD. We conducted a systematic review including all trials and observational studies that reported pain in people with ADPKD. Items from all measures were categorized into content and measurement dimensions of pain. We assessed the general characteristics and psychometric properties of all measures. 118 studies, we identified 26 measures: 12 (46%) measures were developed for a non-ADPKD population, 1 (4%) for chronic kidney disease, 2 (8%) for polycystic liver disease and 11 (42%) specifically for ADPKD. Ten anatomical sites were included, with the lower back the most common (10 measures [39%]), four measurement dimensions (intensity (23 [88%]), frequency (3 [12%]), temporality (2 [8%]), and sensory (21 [81%]), two pain types, nociceptive including visceral (15 [58%]) and somatic (5 [20%]), and neuropathic (2 [8%]), and twelve impact dimensions, where the most frequent was work (5 [31%]). The validation data for the measures were variable and only the ADPKD Impact Scale reported all psychometric domains. The measures for pain in ADPKD varied in terms of content and length, and most had not been validated in ADPKD. A standardized psychometrically robust measure that captures patient-important dimensions of pain is needed to evaluate and manage this debilitating complication of ADPKD.

Synthetic Conjugates of Ursodeoxycholic Acid Inhibit Cystogenesis in Experimental Models of Polycystic Liver Disease

BACKGROUND AND AIMS

Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of symptomatic biliary cysts. Current surgical and pharmacological approaches are ineffective, and liver transplantation represents the only curative option. Ursodeoxycholic acid (UDCA) and histone deacetylase 6 inhibitors (HDAC6is) have arisen as promising therapeutic strategies, but with partial benefits.

APPROACH AND RESULTS

Here, we tested an approach based on the design, synthesis, and validation of a family of UDCA synthetic conjugates with selective HDAC6i capacity (UDCA-HDAC6i). Four UDCA-HDAC6i conjugates presented selective HDAC6i activity, UDCA-HDAC6i #1 being the most promising candidate. UDCA orientation within the UDCA-HDAC6i structure was determinant for HDAC6i activity and selectivity. Treatment of polycystic rats with UDCA-HDAC6i #1 reduced their hepatomegaly and cystogenesis, increased UDCA concentration, and inhibited HDAC6 activity in liver. In cystic cholangiocytes UDCA-HDAC6i #1 restored primary cilium length and exhibited potent antiproliferative activity. UDCA-HDAC6i #1 was actively transported into cells through BA and organic cation transporters.

CONCLUSIONS

These UDCA-HDAC6i conjugates open a therapeutic avenue for PLDs.

Review: Pathogenesis of cholestatic liver diseases

Cholestatic liver diseases (CLD) begin to develop after an impairment of bile flow start to affect the biliary tree. Cholangiocytes actively participate in the liver response to injury and repair and the intensity of this reaction is a determinant factor for the development of CLD. Progressive cholangiopathies may ultimately lead to end-stage liver disease requiring at the end orthotopic liver transplantation. This narrative review will discuss cholangiocyte biology and pathogenesis mechanisms involved in four intrahepatic CLD: Primary biliary cholangitis, primary sclerosing cholangitis, cystic fibrosis involving the liver, and polycystic liver disease.

Polycystic liver disease: Classification, diagnosis, treatment process, and clinical management

Polycystic liver disease (PLD) is a rare hereditary disease that independently exists in isolated PLD, or as an accompanying symptom of autosomal dominant polycystic kidney disease and autosomal recessive polycystic kidney disease with complicated mechanisms. PLD currently lacks a unified diagnostic standard. The diagnosis of PLD is usually made when the number of hepatic cysts is more than 20. Gigot classification and Schnelldorfer classification are now commonly used to define severity in PLD. Most PLD patients have no clinical symptoms, and minority with severe complications need treatments. Somatostatin analogues, mammalian target of rapamycin inhibitor, ursodeoxycholic acid and vasopressin-2 receptor antagonist are the potentially effective medical therapies, while cyst aspiration and sclerosis, transcatheter arterial embolization, fenestration, hepatic resection and liver transplantation are the options of invasion therapies. However, the effectiveness of these therapies except liver transplantation are still uncertain. Furthermore, there is no unified strategy to treat PLD between medical centers at present. In order to better understand recent study progresses on PLD for clinical practice and obtain potential directions for future researches, this review mainly focuses on the recent progress in PLD classification, clinical manifestation, diagnosis and treatment. For information, we also provided medical treatment processes of PLD in our medical center.

Management of portal hypertension and ascites in polycystic liver disease

Patients suffering from polycystic liver disease may develop Hepatic Venous Outflow Obstruction, Portal Vein Obstruction and/or Inferior Caval Vein Syndrome because of cystic mass effect. This can cause portal hypertension, leading to ascites, variceal haemorrhage or splenomegaly. For this review, we evaluate the evidence to provide clinical guidance for physicians faced with this complication. Diagnosis is made with imaging such as ultrasound, computed tomography or magnetic resonance imaging. Therapy includes conventional therapy with diuretics and paracentesis, and medical therapy using somatostatin analogues. Based on disease phenotype various (non-)surgical liver-volume reducing therapies, hepatic or portal venous stenting, transjugular intrahepatic portosystemic shunts and liver transplantation may be considered. Because of complicated anatomy, use of high-risk interventions and lack of empirical evidence, patients should be treated in expert centres.

Pathobiology of inherited biliary diseases: a roadmap to understand acquired liver diseases

Bile duct epithelial cells, also known as cholangiocytes, regulate the composition of bile and its flow. Acquired, congenital and genetic dysfunctions in these cells give rise to a set of diverse and complex diseases, often of unknown aetiology, called cholangiopathies. New knowledge has been steadily acquired about genetic and congenital cholangiopathies, and this has led to a better understanding of the mechanisms of acquired cholangiopathies. This Review focuses on findings from studies on Alagille syndrome, polycystic liver diseases, fibropolycystic liver diseases (Caroli disease and congenital hepatic fibrosis) and cystic fibrosis-related liver disease. In particular, knowledge on the role of Notch signalling in biliary repair and tubulogenesis has been advanced by work on Alagille syndrome, and investigations in polycystic liver diseases have highlighted the role of primary cilia in biliary pathophysiology and the concept of biliary angiogenic signalling and its role in cyst growth and biliary repair. In fibropolycystic liver disease, research has shown that loss of fibrocystin generates a signalling cascade that increases β-catenin signalling, activates the NOD-, LRR- and pyrin domain-containing 3 inflammasome, and promotes production of IL-1β and other chemokines that attract macrophages and orchestrate the process of pericystic and portal fibrosis, which are the main mechanisms of progression in cholangiopathies. In cystic fibrosis-related liver disease, lack of cystic fibrosis transmembrane conductance regulator increases the sensitivity of epithelial Toll-like receptor 4 that sustains the secretion of nuclear factor-κB-dependent cytokines and peribiliary inflammation in response to gut-derived products, providing a model for primary sclerosing cholangitis. These signalling mechanisms may be targeted therapeutically and they offer a possibility for the development of novel treatments for acquired cholangiopathies.

Estrogen-Containing Oral Contraceptives Are Associated With Polycystic Liver Disease Severity in Premenopausal Patients

The association between estrogen-containing oral contraceptives and history of pregnancies with disease severity in women with polycystic liver disease (PLD) is unclear. We performed a cross-sectional cohort study to assess this association by selecting female patients with PLD of which imaging was available prior to any liver volume-reducing therapy. Patients received a questionnaire to collect detailed information on estrogen use and pregnancies. Preplanned subgroup analyses were performed on premenopausal and postmenopausal patients. The questionnaire was returned by 287 of 360 selected patients (80%). There was no significant association between estrogen-containing oral contraceptives and height-adjusted total liver volume (hTLV) in the total group (P = 0.06) and postmenopausal subgroup (P = 0.7). By contrast, each year of exposure corresponds with a 1.45% higher hTLV (P = 0.02) in the premenopausal subgroup, equivalent to a 15.5% higher hTLV for every 10 years of use. Pregnancy duration was not associated with hTLV. In conclusion, patients with PLD should avoid exogenous estrogens.

Long-term results of liver transplantation for polycystic liver disease: Single-center experience in China

The aim of the present study was to explore the indications for and safety of orthotopic liver transplantation for polycystic liver disease (PLD). Orthotopic liver transplantation in 11 patients with PLD between May 2004 and September 2013 was retrospectively analyzed. Patient epidemiological, clinical and follow-up data were collected. The survival rate was calculated using the Kaplan-Meier method. Over the 10-year period, 11 patients received orthotopic liver transplantation (n=9) and combined liver-kidney transplantation (n=2) for PLD. The recipients' median age was 56 years [(interquartile range (IQR), 52-57 years], and 7 of the patients (63.6%) were classified as having Gigot type II PLD and 4 (36.4%) as having Gigot type III. A total of 8 (72.7%) patients had a severely decreased quality of life (Eastern Cooperative Oncology Group performance status score, ≥3). Only 3 cases (27.3%) were of Class C stage. The mean hospitalization duration was 45.4±15.3 days and the mean length of stay at the intensive care unit was 4.1±1.9 days. The peri-operative mortality was 18.2% and the morbidity was 54.5%. The median follow-up period was 111 months (IQR, 33-132 months). A total of 2 patients died of severe complications after combined liver-kidney transplantation. Furthermore, 1 patient died of ischemia cholangitis during the follow-up period. The actuarial 1-, 5- and 10-year survival rate during the follow-up period was 81.8, 81.8 and 65.5%, respectively. The mean physical component summary score was 87.1±6.9 and the mean mental component summary score was 81.5±6.4. In conclusion, liver transplantation is the only curative procedure for PLD, and the present study indicated that it is relatively and safe and leads to good long-term prognosis and high quality of life. Based on our experience and results, liver transplantation is a primary option for cases of PLD with progressive or advanced symptomatic disease where previous other forms of therapy to palliate symptoms have been insufficient.

Autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and one of the most common causes of end-stage kidney disease. Multiple clinical manifestations, such as enlarged kidneys filled with growing cysts, hypertension, and multiple extrarenal complications, including liver cysts, intracranial aneurysms, and cardiac valvular disease, show that ADPKD is a systemic disorder. New information derived from clinical research using molecular genetics and advanced imaging techniques has provided enhanced tools for assessing the diagnosis and prognosis for individual patients and their families. Phase 3 randomised, placebo-controlled clinical trials have clarified aspects of disease management and a disease-modifying therapeutic drug is now available for patients with high risk of rapid disease progression. These developments provide a strong basis on which to make clear recommendations about the management of affected patients and families. Implementation of these advances has the potential to delay kidney failure, reduce the symptom burden, lessen the risk of cardiovascular complications, and prolong life.

Severity in polycystic liver disease is associated with aetiology and female gender: Results of the International PLD Registry

BACKGROUND & AIMS

Polycystic liver disease (PLD) occurs in two genetic disorders, autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-dominant polycystic liver disease (ADPLD). The aim of this study is to compare disease severity between ADPKD and ADPLD by determining the association between diagnosis and height-adjusted total liver volume (hTLV).

METHODS

We performed a cross-sectional analysis with hTLV as endpoint. Patients were identified from the International PLD Registry (>10 liver cysts) and included in our analysis when PLD diagnosis was made prior to September 2017, hTLV was available before volume-reducing therapy (measured on computed tomography or magnetic resonance imaging) and when patients were tertiary referred. Data from the registry were retrieved for age, diagnosis (ADPKD or ADPLD), gender, height and hTLV.

RESULTS

A total of 360 patients (ADPKD n = 241; ADPLD n = 119) met our inclusion criteria. Female ADPKD patients had larger hTLV compared with ADPLD (P = 0.008). In a multivariate regression analysis, ADPKD and lower age at index CT were independently associated with larger hTLV in females, whereas in males a higher age was associated with larger hTLV. Young females (≤51 years) had larger liver volumes compared with older females (>51 years) in ADPKD.

CONCLUSION

Aetiology is presented as a new risk factor associated with PLD severity. Young females with ADPKD represent a subgroup of PLD patients with the most severe phenotype expressed in hTLV.

UDCA, NorUDCA, and TUDCA in Liver Diseases: A Review of Their Mechanisms of Action and Clinical Applications

Bile acids (BAs) are key molecules in generating bile flow, which is an essential function of the liver. In the last decades, there have been great advances in the understanding of BA physiology, and new insights have emerged regarding the role of BAs in determining cell damage and death in several liver diseases. This new knowledge has helped to better delineate the pathophysiology of cholestasis and the adaptive responses of hepatocytes to cholestatic liver injury as well as of the mechanisms of injury of biliary epithelia. In this context, therapeutic approaches for liver diseases using hydrophilic BA (i.e., ursodeoxycholic acid, tauroursodeoxycholic, and, more recently, norursodeoxycholic acid), have been revamped. In the present review, we summarize current experimental and clinical data regarding these BAs and its role in the treatment of certain liver diseases.

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.

Clinical management of polycystic liver disease

A 41-year old female underwent a computed tomography (CT) scan in 2010 because of symptoms suggestive of appendicitis. Incidentally, multiple liver lesions characterised as cysts were detected. The presence of small to medium sized liver cysts (diameter between <1 cm and 4 cm) in all liver segments (>100 cysts) and absence of kidney cysts in the context of normal renal function led to the clinical diagnosis of autosomal dominant polycystic liver disease (ADPLD). Five years later she was referred to the outpatient clinic with increased abdominal girth, pain in the right upper abdomen and right flank, and early satiety. She had difficulties bending over and could neither cut her toenails nor tie her shoe laces. In her early twenties she had used oral contraception for five years. She has been pregnant twice. Clinical examination showed an enlarged liver reaching into the right pelvic region and crossing the midline of the abdomen. Laboratory testing demonstrated increased gamma-glutamyl transferase (80 IU/L, normal <40 IU/L) and alkaline phosphatase (148 IU/L, normal <100 IU/L) levels. Bilirubin, albumin and coagulation times were within the normal range. A new CT scan in 2015 was compatible with an increased number and size of liver cysts. The diameter of cysts varied between <1 cm and 6 cm (anatomic distribution shown [Fig. 2B]). There were no signs of hepatic venous outflow obstruction, portal hypertension or compression on the biliary tract. Height-adjusted total liver volume (htTLV) increased from 2,667 ml/m in 2012 to 4,047 ml/m in 2015 (height 172 cm). The case we present here is not uncommon, and prompts several relevant questions.

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.

Impact of liver volume on polycystic liver disease-related symptoms and quality of life

Background

Symptoms in polycystic liver disease (PLD) are thought to be caused by compression of organs and structures by the enlarged liver.

Aim

The aim of this article is to assess the impact of liver volume on symptoms and quality of life (QoL) in PLD.

Methods

We included PLD patients from two prospective studies that used the PLD-questionnaire (PLD-Q) for symptom assessment. QoL was assessed through SF-36, summarized in a physical (PCS) and mental (MCS) component score. Liver volume was correlated with PLD-Q total scores. Patients were classified based on height-corrected liver volume in mild (<1600 ml), moderate (1600–3200 ml), and severe (>3200 ml) disease. PLD-Q and QoL (PCS and MCS) scores were compared across disease stages.

Results

We included 82 of 131 patients from the original studies (disease stages; mild n = 26, moderate n = 33, and severe n = 23). Patients with larger liver volume reported higher symptom burden (r = 0.516, p < 0.001). Symptom scores increased with disease progression, except for abdominal pain (p = 0.088). PCS decreased with advancing disease (p < 0.001), in contrast to MCS (p = 0.055). Moderate (p = 0.007) and severe (p < 0.001) PLD patients had lower PCS scores than the general population.

Conclusion

PLD with larger liver volume is more likely to be symptomatic and is associated with lower QoL.