Interferon Therapy Exacerbated Pulmonary Hypertension in a Patient with Hepatitis C Virus Infection: Pathogenic Interplay among Multiple Risk Factors

Association between the albumin-bilirubin (ALBI) score and severity of portopulmonary hypertension (PoPH): A data-mining analysis

INTRODUCTION

Portopulmonary hypertension (PoPH) is a severe complication of chronic liver disease. We aimed to investigate the etiology of chronic liver disease and the factors associated with the severity of PoPH.

SUBJECTS AND METHODS

Echocardiography was undergone in 833 patients with chronic liver disease during 2005-2019 and 13 patients (1.6%) were diagnosed with PoPH in this observational study. At the diagnosis of PoPH, liver function was evaluated by albumin-bilirubin (ALBI) score. Severe PoPH was defined as (1) mean pulmonary arterial pressure (mPAP) ≥50 mmHg or (2) mPAP: 35-49 mmHg and pulmonary vascular resistance ≥400 dyne/s/cm⁵ . Factors associated with severe PoPH were evaluated by decision-tree analysis.

RESULTS

In patients with PoPH, the leading etiology of chronic liver disease was hepatitis C virus (HCV) (46.2% [sustained virological response (SVR): 23.1% and non-SVR: 15.4%]). Severe PoPH was observed in 53.8% of patients and the 5-year survival rate was 48.1%. There was a significant correlation of mPAP with ALBI score (r = 0.6456, p = 0.0171). In the decision-tree and random forest analyses, the most impacted classifier for severe PoPH was the ALBI score. In patients with ALBI score ≥-1.45, all patients showed severe PoPH, while the prevalence of severe PoPH was 25.0% in patients with ALBI score <-1.45.

CONCLUSIONS

We found that HCV including SVR was the major etiology of chronic liver disease in patients with PoPH. Moreover, we revealed that the ALBI score was the most impacted factor associated with severe PoPH. Thus, ALBI score may be useful for the estimation of pulmonary vascular resistance.

Association of COVID-19 and other viral infections with interstitial lung diseases, pulmonary fibrosis, and pulmonary hypertension: A narrative review

Background

Interstitial lung diseases (ILDs) include a broad range of diffuse parenchymal lung disorders and are characterized by diffuse parenchymal lung abnormalities leading to irreversible fibrosis. ILDs are correlated with the occurrence of pulmonary fibrosis (PF), which generally also results in pulmonary hypertension (PH). Interferons, secreted in larger amounts during viral infections, are an important possible risk factor contributing to this outcome.

Aims

In this narrative review, the role of 10 different viral infections on the generation/development of ILDs and their outcomes are described in detail. The aim of this review is to determine the probable risk that COVID-19 and other viral infections pose in the post-infection development of ILDs, PF, and PH.

Methods

Searches in PubMed (Medline), Google Scholar, Web of Science (ISI, Researcher ID, Publons), ResearchGate, Scopus, and secondary sources yielded 134 studies. After exclusion criteria, 92 studies containing the terms “Coronavirus” (COVID-19), “Interstitial Lung Diseases,” “Pulmonary Fibrosis,” “Pulmonary Hypertension” and “viral infections” were selected for inclusion. Selected articles were read with a focus on the roles of the 10 commonly studied viral infections on generation/intensification of ILDs and classified according to their dominant effect on the respiratory system, with a focus on each infection’s effects on parenchyma of the lungs and generation and/or intensification of ILDs.

Results

This review found that ILDs, PF, and PH can occur after a COVID-19 viral infection. Similar results are also seen in post-infection cases of other viral infections, including Epstein–Barr virus, Cytomegalovirus, Human herpesvirus-8, adenovirus, Hepatitis C, Torque-Teno (Transfusion-Transmitted) Virus, Human Immunodeficiency Virus, Severe Acute Respiratory Syndrome, and Middle East Respiratory Syndrome.

Conclusion

Results of current studies show probable possibility for generation and/or intensification of ILDs in COVID-19 infected patients like other studied viruses. Studies on determination of the actual prevalence of ILD, PF and PH in post-COVID-19 infected patients, follow-up studies on the prevention of ILDs in recovered COVID-19 patients, and meta-analyzed studies on pulmonary outcomes of pandemic corona viruses are strongly recommended as topics for future studies.

RNA Signaling in Pulmonary Arterial Hypertension-A Double-Stranded Sword

Recognition of and response to pathogens and tissue injury is driven by the innate immune system via activation of pattern recognition receptors. One of the many patterns recognized is RNA and, while several receptors bind RNA, Toll-like receptor 3 (TLR3) is well placed for initial recognition of RNA molecules due to its localization within the endosome. There is a growing body of work describing a role for TLR3 in maintenance of vascular homeostasis. For example, TLR3 deficiency has been shown to play repair and remodeling roles in the systemic vasculature and in lung parenchyma. A hallmark of pulmonary arterial hypertension (PAH) is pulmonary vascular remodeling, yet drivers and triggers of this remodeling remain incompletely understood. Based on its role in the systemic vasculature, our group discovered reduced endothelial TLR3 expression in PAH and revealed a protective role for a TLR3 agonist in rodent models of pulmonary hypertension. This review will provide an overview of RNA signaling in the vasculature and how it relates to PAH pathobiology, including whether targeting double-stranded RNA signaling is a potential treatment option for PAH.

A case of suspected portal-pulmonary hypertension due to hepatitis C virus infection

A 44-year-old woman with chronic hepatitis C virus (HCV) infection was referred by a primary care doctor and admitted to our hospital because of worsening dyspnea on exertion and right atrial and ventricular enlargement. The patient was diagnosed with pulmonary arterial hypertension (PAH) associated with portal hypertension induced by chronic HCV infection. This diagnosis was based on a cardiological examination and findings related to liver cirrhosis with portal hypertension. After the prescription of anti-PAH medicine and a slight improvement in her respiratory symptoms, 12-week direct-acting antiviral (DAA) treatment for HCV was started. Serum HCV RNA levels rapidly decreased and HCV elimination was confirmed 24 weeks after completing DAA treatment. Before confirmation of a sustained virological response at 24 weeks after completing DAA treatment, a remarkable improvement in her cardiac markers was found in a right heart catheter study. This study was performed 6 weeks after the end of DAA administration. Therefore, we considered that HCV infection was involved in the development of PAH and that elimination of HCV by interferon-free treatment was important for this patient.

Aicardi goutières syndrome is associated with pulmonary hypertension

While pulmonary hypertension (PH) is a potentially life threatening complication of many inflammatory conditions, an association between Aicardi Goutières syndrome (AGS), a rare genetic cause of interferon (IFN) overproduction, and the development of PH has not been characterized to date. We analyzed the cardiac function of individuals with AGS enrolled in the Myelin Disorders Bioregistry Project using retrospective chart review (n = 61). Additional prospective echocardiograms were obtained when possible (n = 22). An IFN signature score, a marker of systemic inflammation, was calculated through the measurement of mRNA transcripts of type I IFN-inducible genes (interferon signaling genes or ISG). Pathologic analysis was performed as available from autopsy samples. Within our cohort, four individuals were identified to be affected by PH: three with pathogenic gain-of-function mutations in the IFIH1 gene and one with heterozygous TREX1 mutations. All studied individuals with AGS were noted to have elevated IFN signature scores (Mann-Whitney p < .001), with the highest levels in individuals with IFIH1 mutations (Mann-Whitney p < .0001). We present clinical and histologic evidence of PH in a series of four individuals with AGS, a rare interferonopathy. Importantly, IFIH1 and TREX1 may represent a novel cause of PH. Furthermore, these findings underscore the importance of screening all individuals with AGS for PH.

Modulation of the Immune System in Chronic Hepatitis C and During Antiviral Interferon-Free Therapy

The treatment of patients with chronic hepatitis C virus (HCV) infection has changed tremendously over the past 2 years, with an increasing variety of all-oral direct-acting antiviral (DAA) treatment regimens available for different HCV genotypes and distinct clinical settings. These treatments have significantly improved safety in patients with advanced liver disease compared with interferon (IFN)-based regimens. HCV modifies the human immune system to escape immunosurveillance via several mechanisms. One of the basic mechanisms of HCV is the ability to “switch” the immune response by reducing the activity of cells responsible for the elimination of virus-infected cells. IFN-free DAA treatment regimens provide a unique opportunity to assess the effect of HCV elimination on the immune system. Abrupt changes in the immune system can in some cases be responsible for two alarming processes: viral reactivation in patients with chronic hepatitis B and recurrence of hepatocellular carcinoma in patients with previous successful cancer treatment.