An update on the pathophysiology and management of polycystic liver disease

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.

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part I - Cystic lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the first part of the guideline, concerning the characterization of focal hepatic lesions detected by ultrasound, and the diagnosis and clinical management of simple and parasitic hepatic cysts, and of polycystic 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.

Relationships between congenital peritoneopericardial diaphragmatic hernia or congenital central diaphragmatic hernia and ductal plate malformations in dogs and cats

OBJECTIVE

To characterize the association between peritoneopericardial diaphragmatic hernia (PPDH) or congenital central diaphragmatic hernia (CCDH) and ductal plate malformations (DPMs) in dogs and cats.

ANIMALS

18 dogs and 18 cats with PPDH or CCDH and 19 dogs and 18 cats without PPDH or CCDH.

PROCEDURES

Evaluation of clinical details verified PPDH or CCDH and survival times. Histologic features of nonherniated liver samples were used to categorize DPM. Immunohistochemical staining for cytokeratin-19 distinguished bile duct profiles per portal tract and for Ki-67-assessed cholangiocyte proliferation. Histologic features of herniated liver samples from PPDH or CCDH were compared with those of pathological controls (traumatic diaphragmatic hernia, n = 6; liver lobe torsion, 6; ischemic hepatopathy, 2).

RESULTS

DPM occurred in 13 of 18 dogs with the proliferative-like phenotype predominating and in 15 of 18 cats with evenly distributed proliferative-like and Caroli phenotypes. Congenital hepatic fibrosis DPM was noted in 3 dogs and 2 cats and renal DPM in 3 dogs and 3 cats. No signalment, clinical signs, or clinicopathologic features discriminated DPM. Kaplan Meier survival curves were similar in dogs and cats. Bile duct profiles per portal tract in dogs (median, 5.0; range, 1.4 to 100.8) and cats (6.6; 1.9 to 11.0) with congenital diaphragmatic hernias significantly exceeded those in healthy dogs (1.4; 1.2 to 1.6) and cats (2.3; 1.7 to 2.6). Animals with DPM lacked active cholangiocyte proliferation. Histologic features characterizing malformative bile duct profiles yet without biliary proliferation were preserved in herniated liver lobes in animals with DPM.

CONCLUSIONS AND CLINICAL RELEVANCE

DPM was strongly associated with PPDH and CCDH. Because DPM can impact health, awareness of its coexistence with PPDH or CCDH should prompt biopsy of nonherniated liver tissue during surgical correction of PPDH and CCDH.

Cholestasis Due to USP53 Deficiency

OBJECTIVES

Although a number of genetic forms of cholestasis have been identified, the genetic etiology of disease remains unidentified in a subset of cholestasis patients.

METHODS

Whole exome sequencing (WES) was performed in DNA from patients diagnosed with cholestasis, at different points on the continuum from progressive familial intrahepatic cholestasis to benign recurrent intrahepatic cholestasis, in whom no disease mutations in known cholestasis genes had been identified. Candidate genes were then assessed in a larger patient sample, by targeted next-generation sequencing (NGS). Disease features at presentation and follow-up were collected from available medical records.

RESULTS

By WES, we identified 3 patients with homozygous mutations in USP53. Screening of USP53 in a larger set of patients identified 4 additional patients with homozygous mutations in USP53. Six of the 7 patients had deletion mutations, and 1 had a missense mutation; 3 of the patients were siblings, all bearing a deletion that also disrupted neighboring MYOZ2. Age of onset ranged from early infancy to adolescence. Cholestasis tended to be biochemically mild and intermittent, and responsive to medication. Liver fibrosis was, however, present in all 4 patients who were biopsied, and splenomegaly was apparent in 5 of 7 at last ultrasound.

CONCLUSIONS

Two groups recently identified patients with liver disease and mutation in USP53. We have now identified biallelic mutation in USP53 in 7 further patients with cholestasis, from 5 families. Most individuals had evidence of chronic liver disease, and long-term follow-up is recommended.

Liver transplantation for rare liver diseases and rare indications for liver transplant

Liver transplantation (LT) is currently considered the gold standard treatment for end-stage liver failure. Compared to the first decades of its use, LT is associated with lower comorbidity and mortality, with a 5-year survival over 70%. Worldwide, liver cirrhosis and hepatocellular carcinoma represent the major indications to LT. However, almost 1% of LT is performed for rare diseases or rare indications, which include non-hepatocellular malignancy, vascular disorders, metabolic and congenital liver disorders. These diseases can lead to hepatocellular necrosis, biliary tree abnormality and/or hepatomegaly. Most of these diseases are not associated with liver failure but in highly selected patients, LT represent an effective therapy improving the overall survival and quality of life. Rare indications for LT often overlap with rare diseases. However, rare LT indications for non-rare diseases are rising in the last decades, especially for benign primary liver tumor, colon rectal liver metastasis, neuroendocrine liver metastasis, and cholangiocarcinoma (CCA). Non-rare diseases with rare indication for LT and rare adult disease with an indication for LT are categorized and discussed in detail, focusing on some disorders for which the literature provides a more definitive evidence base. Early referral to a transplant center is encouraged to provide an effective therapeutic option in these non-standard indications for LT.

INASL-ISN Joint Position Statements on Management of Patients with Simultaneous Liver and Kidney Disease

Renal dysfunction is very common among patients with chronic liver disease, and concomitant liver disease can occur among patients with chronic kidney disease. The spectrum of clinical presentation and underlying etiology is wide when concomitant kidney and liver disease occur in the same patient. Management of these patients with dual onslaught is challenging and requires a team approach of hepatologists and nephrologists. No recent guidelines exist on algorithmic approach toward diagnosis and management of these challenging patients. The Indian National Association for Study of Liver (INASL) in association with Indian Society of Nephrology (ISN) endeavored to develop joint guidelines on diagnosis and management of patients who have simultaneous liver and kidney disease. For generating these guidelines, an INASL-ISN Taskforce was constituted, which had members from both the societies. The taskforce first identified contentious issues on various aspects of simultaneous liver and kidney diseases, which were allotted to individual members of the taskforce who reviewed them in detail. A round-table meeting of the Taskforce was held on 20-21 October 2018 at New Delhi to discuss, debate, and finalize the consensus statements. The evidence and recommendations in these guidelines have been graded according to the Grading of Recommendations Assessment Development and Evaluation (GRADE) system with minor modifications. The strength of recommendations (strong and weak) thus reflects the quality (grade) of underlying evidence (I, II, III). We present here the INASL-ISN Joint Position Statements on Management of Patients with Simultaneous Liver and Kidney 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.

Severe polycystic liver diseases: hepatectomy or waiting for liver transplantation?: Two case reports

INTRODUCTION

Choice of treatment in patients with symptomatic polycystic liver diseases (PLD) remains controversial. Various surgical procedures aiming at eliminating symptomatic cysts are widely used in mild and advanced PLD patients, but liver transplantation is currently recommended as the only curative treatment especially in severe cases.

PATIENT CONCERNS

Case 1: A 51-year-old male was admitted for severe eating disorder and dyspnea for 2 months. He had been diagnosed as PLD, PKD, and hypertension for 9 years, with only antihypertensive drug therapy. No significant family history could be traced.Case 2: A 54-year-old female was admitted to our hospital for ventosity during nearly 5 years. She had been diagnosed as PLD and hypertension for 22 years, for which only aspiration-sclerotherapy therapy was performed for multiple times. Both her mother and sister were diagnosed with PLD previously.

DIAGNOSIS

They were diagnosed as PLD by medical history, family history, and computed tomography scan (multiple cysts dispersively presenting in the liver).

INTERVENTIONS

The 2 patients underwent hepatectomy with fenestration, and were well recovered with no mortality.

OUTCOMES

While case 1 only experienced relief of symptoms, case 2 experienced massive growth of hepatic parenchyma, which indicated positive prognosis and showed the possibility to avoid or at least postpone liver transplantation for a long time, considering the lack of liver parenchyma is one of the main reason for urgency of liver transplantation.

CONCLUSION

Here we described subradical polycystic hepatectomy, a special form of hepatectomy with fenestration modified by us, as a safe and effective treatment to potentially achieve long-term effects in PLD patients.

Molecular components and polarity of radial glial cells during cerebral cortex development

Originating from ectodermal epithelium, radial glial cells (RGCs) retain apico-basolateral polarity and comprise a pseudostratified epithelial layer in the developing cerebral cortex. The apical endfeet of the RGCs faces the fluid-filled ventricles, while the basal processes extend across the entire cortical span towards the pial surface. RGC functions are largely dependent on this polarized structure and the molecular components that define it. In this review, we will dissect existing molecular evidence on RGC polarity establishment and during cerebral cortex development and provide our perspective on the remaining key questions.