Pathophysiology and Diseases of the Proximal Pathways of the Biliary System

Magnetic resonance imaging features of progressive familial intrahepatic cholestasis type 3

PURPOSE

Progressive familial intrahepatic cholestasis type 3 (PFIC-3) is a rare autosomal recessive cholestatic liver disorder. This study aimed to present the clinical and magnetic resonance imaging (MRI) features of three patients with PFIC‑3.

METHODS

The study included three patients with cholestasis and pathogenic variants in the ABCB4 gene identified by next-generation sequencing of a targeted-gene panel or by whole-exome sequencing. The clinical, laboratory, histological, molecular, and MRI features of the patients were collected.

RESULTS

Three patients (one male and two females) were enrolled. The age when clinical signs and symptoms were first noted was 21, 14, and 39 years, respectively, and the signs and symptoms included pruritus and splenomegaly (in all three patients). Parenchymatous lace-like fibrosis was associated with periportal hyperintensity and periportal halo sign in three patients. Segmental atrophy was observed in two patients, diffuse atrophy was observed in one patient, and liver surface irregularity caused by regenerating nodules was observed in three patients. Magnetic resonance cholangiopancreatography (MRCP) images showed irregular bile duct changes in three patients, focal hilar bile duct stenosis, and local intrahepatic bile duct dilatation.

CONCLUSIONS

Imaging studies using MRI and MRCP can support the clinical and laboratory results in cases of PFIC‑3 and can also be used as a noninvasive diagnostic option.

Secondary sclerosing cholangitis after COVID-19 pneumonia: a report of two cases and review of the literature

Secondary sclerosing cholangitis in critically ill patients (SC-CIP) is a rare disease characterized by chronic cholestasis. The underlying pathophysiology of SC-CIP is not fully understood, and prognosis in severe cases remains poor with liver transplantation remaining the only curative treatment option. There is a growing amount of literature describing patients with chronic cholangiopathy after COVID-19 infection. The vast majority of the patients described in these reports were male and had a poor outcome. While the exact percentage of patients with COVID-19-related SC-CIP cannot be estimated accurately due to a lack of larger studies, an increase in patients with long-term complications of chronic cholestatic liver disease after severe COVID19-pneumonia can be expected in the upcoming years. Treatment options remain limited and further research is needed to improve the dismal prognosis of SC-CIP. Here, we present the cases of two patients who developed SC-CIP after prolonged intensive care unit stay due to severe COVID-19 pneumonia. Both patients required invasive ventilation for 31 and 141 days, respectively, as well as extra-corporal membrane oxygenation for 23 and 87 days. The patients suffered from jaundice and severe pruritus, and typical features of SC-CIP were present by MRCP and ERC. Repeated removal of biliary casts resulted in some alleviation of their clinical symptoms, but cholestasis parameters remain elevated. Furthermore, an increased liver stiffness was indicative of advanced fibrosis in both patients. In addition to these two case reports, we provide a concise review of the literature of SC-CIP after COVID-19 infection and discuss risk factors, treatment options and prognosis.

Bioprinting of Complex Multicellular Organs with Advanced Functionality-Recent Progress and Challenges Ahead

Bioprinting has emerged as one of the most promising strategies for fabrication of functional organs in the lab as an alternative to transplant organs. While progress in the field has mostly been restricted to a few miniaturized tissues with minimal biological functionality until a few years ago, recent progress has advanced the concept of building three-dimensional multicellular organ complexity remarkably. This review discusses a series of milestones that have paved the way for bioprinting of tissue constructs that have advanced levels of biological and architectural functionality. Critical materials, engineering and biological challenges that are key to addressing the desirable function of engineered organs are presented. These are discussed in light of the many difficulties to replicate the heterotypic organization of multicellular solid organs, the nanoscale precision of the extracellular microenvironment in hierarchical tissues, as well as the advantages and limitations of existing bioprinting methods to adequately overcome these barriers. In summary, the advances of the field toward realistic manufacturing of functional organs have never been so extensive, and this manuscript serves as a road map for some of the recent progress and the challenges ahead.

Arbutin Alleviates the Liver Injury of α-Naphthylisothiocyanate-induced Cholestasis Through Farnesoid X Receptor Activation

Cholestasis is a kind of stressful syndrome along with liver toxicity, which has been demonstrated to be related to fibrosis, cirrhosis, even cholangiocellular or hepatocellular carcinomas. Cholestasis usually caused by the dysregulated metabolism of bile acids that possess high cellular toxicity and synthesized by cholesterol in the liver to undergo enterohepatic circulation. In cholestasis, the accumulation of bile acids in the liver causes biliary and hepatocyte injury, oxidative stress, and inflammation. The farnesoid X receptor (FXR) is regarded as a bile acid–activated receptor that regulates a network of genes involved in bile acid metabolism, providing a new therapeutic target to treat cholestatic diseases. Arbutin is a glycosylated hydroquinone isolated from medicinal plants in the genus Arctostaphylos, which has a variety of potentially pharmacological properties, such as anti-inflammatory, antihyperlipidemic, antiviral, antihyperglycemic, and antioxidant activity. However, the mechanistic contributions of arbutin to alleviate liver injury of cholestasis, especially its role on bile acid homeostasis via nuclear receptors, have not been fully elucidated. In this study, we demonstrate that arbutin has a protective effect on α-naphthylisothiocyanate–induced cholestasis via upregulation of the levels of FXR and downstream enzymes associated with bile acid homeostasis such as Bsep, Ntcp, and Sult2a1, as well as Ugt1a1. Furthermore, the regulation of these functional proteins related to bile acid homeostasis by arbutin could be alleviated by FXR silencing in L-02 cells. In conclusion, a protective effect could be supported by arbutin to alleviate ANIT-induced cholestatic liver toxicity, which was partly through the FXR pathway, suggesting arbutin may be a potential chemical molecule for the cholestatic disease.

Liver transplantation in pediatric patients with progressive familial intrahepatic cholestasis: Single center experience of seven cases

Backgrounds/Aims

Progressive familial intrahepatic cholestasis (PFIC) is an autosomal recessive inherited disease requiring liver transplantation (LT). The objective of this study was to investigate the clinicopathological features and posttransplant courses of seven LT recipients with PFIC.

Methods

This was a retrospective single-center study of patients with PFIC who underwent LT from January 2013 to June 2020.

Results

Two and five patients were diagnosed with PFIC type 1 and type 2, respectively. For all seven patients, age of PFIC onset was at birth. Jaundice was present in all cases. Mean pretransplant total and direct bilirubin levels were 16.1 ± 8.1 mg/dL and 12.4 ± 6.2 mg/dL, respectively. Median patient age and body weight at LT were 10 months and 7 kg, respectively. Types of donors were mothers of patients in four and deceased donors in three. All five patients with PFIC type 2 recovered uneventfully. One patient each with PFIC type 1 underwent retransplantation due to graft failure or died due to multi-organ failure. Overall graft and patient survival rates at five years were 66.7% and 83.3%, respectively. Bile salt export pump immunohistochemical staining showed normal canalicular expression in two patients with PFIC type 1, focal loss in two patients with PFIC type 2, and total loss in three patients with PFIC type 2.

Conclusions

LT is currently the only effective treatment for PFIC-associated end-stage liver diseases. It is mandatory to perform regular follow-up due to the risk of complications including steatohepatitis, especially for patients with PFIC type 1.

Picroside II alleviates liver injury induced by alpha-naphthylisothiocyanate through AMPK-FXR pathway

Alpha-naphthylisothiocyanate (ANIT) is a typical hepatotoxicant that causes cholestasis, which causes toxic bile acid accumulation in the liver and leads to liver injury. Picroside II (PIC), one of the dominant effective components extracted from Picrorhiza scrophulariiflora Pennell, exhibits many pharmacological effects. However, the role of AMP-activated protein kinase (AMPK)-Farnesoid X receptor (FXR) pathway in the hepatoprotective effect of PIC against ANIT-induced cholestasis remains largely unknown. This study aimed to investigate the mechanisms of PIC on ANIT-induced cholestasis in vivo and in vitro. Our results showed that PIC protected against ANIT-induced liver injury in primary mouse hepatocytes, and decreased serum biochemical markers and lessened histological injuries in mice. ANIT inhibited FXR and its target genes of bile acid synthesis enzymes sterol-12α-hydroxylase (CYP8B1), and increase bile acid uptake transporter Na + -dependent taurocholate transporter (NTCP), efflux transporter bile salt export pump (BSEP) and bile acid metabolizing enzymes UDP-glucuronosyltransferase 1a1 (UGT1A1) expressions. PIC prevented its downregulation of FXR, NTCP, BSEP and UGT1A1, and further reduced CYP8B1 by ANIT. Furthermore, ANIT activated AMPK via ERK1/2-LKB1 pathway. PIC inhibited ERK1/2, LKB1 and AMPK phosphorylation in ANIT-induced cholestasis in vivo and in vitro. AICAR, an AMPK agonist, blocked PIC-mediated changes in FXR, CYP8B1 and BSEP expression in vitro. Meanwhile, U0126, an ERK1/2 inhibitor, further repressed ERK1/2-LKB1-AMPK pathway phosphorylation. In conclusion, PIC regulated bile acid-related transporters and enzymes to protect against ANIT-induced liver injury, which related to ERK1/2-LKB1-AMPK pathway. Thus, this study extends the understanding of the anti-cholestasis effect of PIC and provides new therapeutic targets for cholestasis treatment.

Tubular bile duct structure mimicking bile duct morphogenesis for prospective in vitro liver metabolite recovery

Background

Liver metabolites are used to diagnose disease and examine drugs in clinical pharmacokinetics. Therefore, development of an in vitro assay system that reproduces liver metabolite recovery would provide important benefits to pharmaceutical research. However, liver models have proven challenging to develop because of the lack of an appropriate bile duct structure for the accumulation and transport of metabolites from the liver parenchyma. Currently available bile duct models, such as the bile duct cyst-embedded extracellular matrix (ECM), lack any morphological resemblance to the tubular morphology of the living bile duct. Moreover, these systems cannot overcome metabolite recovery issues because they are established in isolated culture systems. Here, we successfully established a non-continuous tubular bile duct structure model in an open-culture system, which closely resembled an in vivo structure. This system was utilized to effectively collect liver metabolites separately from liver parenchymal cells.

Results

Triple-cell co-culture of primary rat hepatoblasts, rat biliary epithelial cells, and mouse embryonic fibroblasts was grown to mimic the morphogenesis of the bile duct during liver development. Overlaying the cells with ECM containing a Matrigel and collagen type I gel mixture promoted the development of a tubular bile duct structure. In this culture system, the expression of specific markers and signaling molecules related to biliary epithelial cell differentiation was highly upregulated during the ductal formation process. This bile duct structure also enabled the separate accumulation of metabolite analogs from liver parenchymal cells.

Conclusions

A morphogenesis-based culture system effectively establishes an advanced bile duct structure and improves the plasticity of liver models feasible for autologous in vitro metabolite-bile collection, which may enhance the performance of high-throughput liver models in cell-based assays.

Familial intrahepatic cholestasis: New and wide perspectives

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) includes autosomal recessive cholestatic rare diseases of childhood.

AIMS

To update the panel of single genes mutations involved in familial cholestasis.

METHODS

PubMed search for "familial intrahepatic cholestasis" alone as well as in combination with other key words was performed considering primarily original studies and meta-analyses.

RESULTS

PFIC1 involves ATP8B1 gene encoding for aminophospholipid flippase FIC1. PFIC2 includes ABCB11 gene, encoding for protein functioning as bile salt export pump. PFIC3 is due to mutations of ABCB4 gene responsible for the synthesis of class III multidrug resistance P-glycoprotein flippase. PFIC4 and PFIC5 involve tight junction protein-2 gene and NR1H4 gene encoding for farnesoid X receptor. Benign Intrahepatic Cholestasis, Intrahepatic Cholestasis of Pregnancy and Low-phospholipid-associated cholelithiasis involve the same genes and are characterized by intermittent attacks of cholestasis, no progression to cirrhosis, reversible pregnancy-specific cholestasis and cholelithiasis in young people. Blood and liver tissue levels of bile-excreted drugs can be influenced by the presence of mutations in PFIC genes, causing drug-induced cholestasis. Mutations in PFIC genes might increase the risk of liver cancer.

CONCLUSION

There is a high proportion of unexplained cholestasis potentially caused by specific genetic pathophysiologic pathways. The use of next generation sequencing and whole-exome sequencing could improve the diagnostic process in this setting.

Novel compound heterozygote mutations of TJP2 in a Chinese child with progressive cholestatic liver disease

Background

Progressive familial intrahepatic cholestasis (PFIC) is a group of genetic autosomal recessive disorders that predominantly affects young children and results in early-onset progressive liver damage. Several types of PFIC were defined based on different genetic aetiologies in last decades.

Case presentation

Here, we report a Chinese young child diagnosed as PFIC with variants in tight junction protein 2 (TJP2). The patient was affected by a long history of jaundice, pruritus, and failure to thrive. Highly elevated level of serum total bile acid (TBA) and normal levels of gamma-glutamyltransferase (GGT) were observed at hospitalization. The patient’s clinical symptoms could be alleviated by administration of ursodeoxycholic acid. Genetic testing by next generation sequencing (NGS) found novel compound heterozygote mutations c.2448 + 1G > C/c.2639delC (p.T880Sfs*12) in TJP2, which were inherited from her mother and father, respectively. Both mutations were predicted to abolish TJP2 protein translation, and neither has previously been identified.

Conclusion

We report a Chinese female PFIC child with novel compound heterozygous mutations of TJP2. Genetic testing by NGS is valuable in the clinical diagnosis of hereditary liver disease.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0753-7) contains supplementary material, which is available to authorized users.

Liver Transplantation for Progressive Familial Intrahepatic Cholestasis

BACKGROUND Progressive familial intrahepatic cholestasis (PFIC) is an autosomal recessive inherited disease that disrupts the genes for bile formation. Liver transplantation (LT) is the only effective treatment for PFIC patients with end-stage liver disease. We describe our experience in terms of clinical characteristics, complications, and outcome of LT for PFIC. CASE REPORT The data of 5 pediatric PFIC patients recipients (3 PFIC1, 1 PFIC2, and 1 PFIC3) who received LT at our Liver Transplant Center from June 2013 to February 2017 were retrospectively analyzed. Four patients received liver transplantation from donation after cardiac death (DCD) donors. One patient received a living donor liver transplantation (LDLT). All the LT recipients received an immunosuppressive regimen of tacrolimus (FK 506) + methylprednisolone + mycophenolate mofetil (MMF). Diarrhea did not improve in 2 PFIC1 patients after LT, and they both developed steatohepatitis several months after LT. The other PFIC1 patient received ABO blood group incompatible LT and developed biliary complications and a severe Epstein-Barr virus infection; this patient underwent endoscopic retrograde cholangiopancreatography. She recovered after treatment with ganciclovir and reduction of tacrolimus dosage. The PFIC2 patient had abnormal liver function 19 months after LT, and recovered after administration of increased dosage of immunosuppressant agents. Liver function in the PFIC3 patient was normal during 2-year follow-up. CONCLUSIONS Liver transplantation is an effective treatment in PFIC patients. However, PFIC1 patients may develop aggravated diarrhea and steatohepatitis after LT. PFIC2 and PFIC3 patients have good outcomes after LT.

Balancing Medical and Non-Accidental Causes of Multiple Fractures in a Child with Progressive Familial Intrahepatic Cholestasis

Patient: Female, 2

Final Diagnosis: Hepatic rickets

Symptoms: Pain

Medication: —

Clinical Procedure: Skeletal survey

Specialty: Pediatrics and Neonatology

A 10-year-old child presenting with syndromic paucity of bile ducts (Alagille syndrome): a case report

Background

Alagille syndrome, a rare genetic disorder with autosomal dominant transmission, manifests with five major features: paucity of interlobular bile ducts, characteristic facies, posterior embryotoxon, vertebral defects, and peripheral pulmonary stenosis. Globally, only 500 cases have so far been reported, with only five cases reported in the Indian subcontinent. Rarely, Alagille syndrome also presents with skin manifestations and early-onset chronic liver disease, which was found in our case. We believe that we report what could be the first case of Alagille syndrome presenting with café au lait spots, as no such published case report could be found in the literature.

Case presentation

We report an unusual case of childhood cholestatic jaundice with neonatal onset of jaundice. A 10-year-old boy from the Indian subcontinent presented with obstructive jaundice from early infancy. He also had recurrent fractures of his upper limb bones, intermittent bleeding from his nose, productive cough, decreased night vision, hyperpigmented spots over his skin, and progressive enlargement of his abdomen. Histological examination of a liver biopsy specimen revealed a paucity of bile ducts and changes suggestive of chronic liver disease. Our patient was diagnosed with Alagille syndrome and managed conservatively but died 1 year after the final diagnosis.

Conclusions

This particular syndromic form of paucity of bile duct disorder has been rarely reported in the Indian literature so far. Our case is notable because the child had café au lait spots and very early onset of chronic liver disease, which is quite rare in Alagille syndrome. We believe this to be the first case report on Alagille syndrome manifesting with café au lait syndrome and such early onset of chronic liver disease.

Liver transplantation and the management of progressive familial intrahepatic cholestasis in children

Progressive familial intrahepatic cholestasis (PFIC) is a constellation of inherited disorders that result in the impairment of bile flow through the liver that predominantly affects children. The accumulation of bile results in progressive liver damage, and if left untreated leads to end stage liver disease and death. Patients often present with worsening jaundice and pruritis within the first few years of life. Many of these patients will progress to end stage liver disease and require liver transplantation. The role and timing of liver transplantation still remains debated especially in the management of PFIC1. In those patients who are appropriately selected, liver transplantation offers an excellent survival benefit. Appropriate timing and selection of patients for liver transplantation will be discussed, and the short and long term management of patients post liver transplantation will also be described.

How to apply clinical cases and medical literature in the framework of a modified "failure mode and effects analysis" as a clinical reasoning tool--an illustration using the human biliary system

BACKGROUND

Clinicians use various clinical reasoning tools such as Ishikawa diagram to enhance their clinical experience and reasoning skills. Failure mode and effects analysis, which is an engineering methodology in origin, can be modified and applied to provide inputs into an Ishikawa diagram.

METHOD

The human biliary system is used to illustrate a modified failure mode and effects analysis. The anatomical and physiological processes of the biliary system are reviewed. Failure is defined as an abnormality caused by infective, inflammatory, obstructive, malignancy, autoimmune and other pathological processes. The potential failures, their effect(s), main clinical features, and investigation that can help a clinician to diagnose at each anatomical part and physiological process are reviewed and documented in a modified failure mode and effects analysis table. Relevant medical and surgical cases are retrieved from the medical literature and weaved into the table.

RESULTS

A total of 80 clinical cases which are relevant to the modified failure mode and effects analysis for the human biliary system have been reviewed and weaved into a designated table. The table is the backbone and framework for further expansion. Reviewing and updating the table is an iterative and continual process. The relevant clinical features in the modified failure mode and effects analysis are then extracted and included in the relevant Ishikawa diagram.

CONCLUSIONS

This article illustrates an application of engineering methodology in medicine, and it sows the seeds of potential cross-pollination between engineering and medicine. Establishing a modified failure mode and effects analysis can be a teamwork project or self-directed learning process, or a mix of both. Modified failure mode and effects analysis can be deployed to obtain inputs for an Ishikawa diagram which in turn can be used to enhance clinical experiences and clinical reasoning skills for clinicians, medical educators, and students.