Kupffer Cell Hyaline Globules in Children With Autoimmune Hepatitis

BACKGROUND

Hyaline globules (HGs) in the cytoplasm of Kupffer cells (KCs) have been appraised for being a typical feature of autoimmune hepatitis (AIH). This study aimed to determine how useful Kupffer cell hyaline globules (KCHGs) are in diagnosing AIH vs. other causes of pediatric chronic liver diseases (PCLDs).

MATERIALS AND METHODS

This retrospective study recruited 124 children; 58 with AIH, 50 with chronic hepatitis C virus (HCV) infection, and 16 with Wilson's disease (WD). Two pathologists retrieved paraffin blocks of liver biopsies and prepared new cut sections for Periodic acid-Schiff-Diastase (PAS-D) stain. They independently examined liver biopsies before starting treatment. Two pediatricians reviewed medical records for demographic, clinical, laboratory, and serological findings.

RESULTS

Females represented 48.6% of the studied children with a median age of 5.8 (4.9) years. Pathologists identified KCHGs in 67.24%, 12.5%, and 6.0% of AIH, WD, and HCV affected children respectively, P < 0.001. A significantly higher proportion of seropositive than seronegative AIH patients had KCHGs (77.5% vs. 50.0%), (P < 0.05). In multivariate analysis, KCHGs and prolonged prothrombin time were the only significant predictors that differentiate between AIH and the other studied PCLDs. The odds ratio of having AIH increased 68 times if KCHGs were seen. Among children with AIH, the presence of KCHGs was associated with higher median levels of direct bilirubin 2.2 (1.3) vs. 1.2 (2.2), and immunoglobulin G 3.2 (1.9) vs. 2.0 (1.7), (P < 0.05), but not to histopathological findings or hepatic fibrosis and activity.

CONCLUSIONS

KCHGs are key indicators that can differentiate between AIH and other PCLDs, and between seropositive and seronegative AIH.

CRISPR-targeted genome editing of human induced pluripotent stem cell-derived hepatocytes for the treatment of Wilson's disease

Background & Aims

Wilson’s disease (WD) is an autosomal recessive disorder of copper metabolism caused by loss-of-function mutations in ATP7B, which encodes a copper-transporting protein. It is characterized by excessive copper deposition in tissues, predominantly in the liver and brain. We sought to investigate whether gene-corrected patient-specific induced pluripotent stem cell (iPSC)-derived hepatocytes (iHeps) could serve as an autologous cell source for cellular transplantation therapy in WD.

Methods

We first compared the in vitro phenotype and cellular function of ATP7B before and after gene correction using CRISPR/Cas9 and single-stranded oligodeoxynucleotides (ssODNs) in iHeps (derived from patients with WD) which were homozygous for the ATP7B R778L mutation (ATP7B^R778L/R778L). Next, we evaluated the in vivo therapeutic potential of cellular transplantation of WD gene-corrected iHeps in an immunodeficient WD mouse model (Atp7b^-/-/ Rag2^-/-/ Il2rg^-/-; ARG).

Results

We successfully created iPSCs with heterozygous gene correction carrying 1 allele of the wild-type ATP7B gene (ATP7B^WT/-) using CRISPR/Cas9 and ssODNs. Compared with ATP7B^R778L/R778L iHeps, gene-corrected ATP7B^WT/- iHeps restored in vitro ATP7B subcellular localization, its subcellular trafficking in response to copper overload and its copper exportation function. Moreover, in vivo cellular transplantation of ATP7B^WT/- iHeps into ARG mice via intra-splenic injection significantly attenuated the hepatic manifestations of WD. Liver function improved and liver fibrosis decreased due to reductions in hepatic copper accumulation and consequently copper-induced hepatocyte toxicity.

Conclusions

Our findings demonstrate that gene-corrected patient-specific iPSC-derived iHeps can rescue the in vitro and in vivo disease phenotypes of WD. These proof-of-principle data suggest that iHeps derived from gene-corrected WD iPSCs have potential use as an autologous ex vivo cell source for in vivo therapy of WD as well as other inherited liver disorders.

Lay summary

Gene correction restored ATP7B function in hepatocytes derived from induced pluripotent stem cells that originated from a patient with Wilson’s disease. These gene-corrected hepatocytes are potential cell sources for autologous cell therapy in patients with Wilson’s disease.

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Correction of the ATP7B R778L mutation restored the subcellular localization of ATP7B in iHeps.

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The copper exportation capability of ATP7B was restored in gene-corrected iHeps.

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Gene-corrected iHeps reduced hepatic copper accumulation and copper-induced hepatic toxicity in mice with Wilson’s disease.

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Gene-corrected iHeps are potential ex vivo cell sources for therapy in Wilson’s disease.

Novel vectors and approaches for gene therapy in liver diseases

Gene therapy is becoming an increasingly valuable tool to treat many genetic diseases with no or limited treatment options. This is the case for hundreds of monogenic metabolic disorders of hepatic origin, for which liver transplantation remains the only cure. Furthermore, the liver contains 10-15% of the body's total blood volume, making it ideal for use as a factory to secrete proteins into the circulation. In recent decades, an expanding toolbox has become available for liver-directed gene delivery. Although viral vectors have long been the preferred approach to target hepatocytes, an increasing number of non-viral vectors are emerging as highly efficient vehicles for the delivery of genetic material. Herein, we review advances in gene delivery vectors targeting the liver and more specifically hepatocytes, covering strategies based on gene addition and gene editing, as well as the exciting results obtained with the use of RNA as a therapeutic molecule. Moreover, we will briefly summarise some of the limitations of current liver-directed gene therapy approaches and potential ways of overcoming them.

Estimating the clinical prevalence of Wilson's disease in the UK

Background & Aims

The clinical prevalence of Wilson’s disease (WD) in the UK remains unknown. The estimated genetic prevalence in the UK, 142/million, is higher than the clinical prevalence (15/million) reported in other European studies. The aim of this study was to estimate the clinical prevalence of WD utilising readily available laboratory and clinical data.

Method

Patients with WD who attended Nottingham University Hospital NHS Trust (NUH) between 2011 and 2018 were identified using multiple sources of case ascertainment: serum ceruloplasmin, 24-hour urinary copper, ‘Wilson’ in liver biopsy report, hospital prescription for penicillamine/trientine/zinc and admission coded with ICD-10 Code E83.0 (disorder of copper metabolism). Potential cases were identified using the Leipzig score, diagnosis was confirmed in hospital records and the point prevalence was calculated using the Office for National Statistics mid-2017 population estimates.

Results

A total of 1,794 patients were identified from ≥1 source; 19 patients had WD, of whom 11 were from within the study catchment area and alive at the time of point prevalence estimation. Twenty-nine patients had a Leipzig score ≥2 without a diagnosis of WD, but none had WD on screening (n = 16). The overall prevalence of WD was 15.5/million; males 16.9/million and females 14.1/million.

Conclusion

This is the first UK population-based study to assess the clinical prevalence of WD. The reported clinical prevalence is lower than the UK genetic prevalence, but comparable to the clinical prevalence reported in Europe. The case ascertainment approach used in this study may be cost-effective, and similar practises could be adopted nationally.

Lay summary

Our study estimates the clinical prevalence of Wilson’s disease, a rare genetic disorder of copper metabolism, in the UK. The estimated clinical prevalence is this study is markedly lower than the estimated UK genetic prevalence.

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The clinical prevalence of Wilson’s disease in the UK is estimated to be 15.5/million (1/64,516).

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The clinical prevalence is significantly lower than the previously reported genetic prevalence.

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Routine clinical and laboratory data can be used to not only find existing cases, but also evaluate potential cases.

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Case ascertainment is potentially a cost-effective approach for Wilson’s disease and other rare diseases.