The complex interrelationships between chronic lung and liver disease: a review

The regional disparities in liver disease comorbidity among elderly Chinese based on a health ecological model: the China Health and Retirement Longitudinal Study

PURPOSE

This study aimed to investigate the risk factors for liver disease comorbidity among older adults in eastern, central, and western China, and explored binary, ternary and quaternary co-morbid co-causal patterns of liver disease within a health ecological model.

METHOD

Basic information from 9,763 older adults was analyzed using data from the China Health and Retirement Longitudinal Study (CHARLS). LASSO regression was employed to identify significant predictors in eastern, central, and western China. Patterns of liver disease comorbidity were studied using association rules, and spatial distribution was analyzed using a geographic information system. Furthermore, binary, ternary, and quaternary network diagrams were constructed to illustrate the relationships between liver disease comorbidity and co-causes.

RESULTS

Among the 9,763 elderly adults studied, 536 were found to have liver disease comorbidity, with binary or ternary comorbidity being the most prevalent. Provinces with a high prevalence of liver disease comorbidity were primarily concentrated in Inner Mongolia, Sichuan, and Henan. The most common comorbidity patterns identified were "liver-heart-metabolic", "liver-kidney", "liver-lung", and "liver-stomach-arthritic". In the eastern region, important combination patterns included "liver disease-metabolic disease", "liver disease-stomach disease", and "liver disease-arthritis", with the main influencing factors being sleep duration of less than 6 h, frequent drinking, female, and daily activity capability. In the central region, common combination patterns included "liver disease-heart disease", "liver disease-metabolic disease", and "liver disease-kidney disease", with the main influencing factors being an education level of primary school or below, marriage, having medical insurance, exercise, and no disabilities. In the western region, the main comorbidity patterns were "liver disease-chronic lung disease", "liver disease-stomach disease", "liver disease-heart disease", and "liver disease-arthritis", with the main influencing factors being general or poor health satisfaction, general or poor health condition, severe pain, and no disabilities.

CONCLUSION

The comorbidities associated with liver disease exhibit specific clustering patterns at both the overall and local levels. By analyzing the comorbidity patterns of liver diseases in different regions and establishing co-morbid co-causal patterns, this study offers a new perspective and scientific basis for the prevention and treatment of liver diseases.

Pulmonary Assessment of the Liver Transplant Recipient

Respiratory symptoms and hypoxemia can complicate chronic liver disease and portal hypertension. Various pulmonary disorders affecting the pleura, lung parenchyma, and pulmonary vasculature are seen in end-stage liver disease, complicating liver transplantation (LT). Approximately 8% of cirrhotic patients in an intensive care unit develop severe pulmonary problems. These disorders affect waiting list mortality and posttransplant outcomes. A thorough history, physical examination, and appropriate laboratory tests help diagnose and assess the severity to risk stratify pulmonary diseases before LT. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH) are respiratory consequences specific to cirrhosis and portal hypertension. HPS is seen in 5-30% of cirrhosis cases and is characterized by impaired oxygenation due to intrapulmonary vascular dilatations and arteriovenous shunts. Severe HPS is an indication of LT. The majority of patients with HPS resolve their hypoxemia after LT. When pulmonary arterial hypertension occurs in patients with portal hypertension, it is called POPH. All other causes of pulmonary arterial hypertension should be ruled out before labeling as POPH. Since severe POPH (mean pulmonary artery pressure [mPAP] >50 mm Hg) is a relative contraindication for LT, it is crucial to screen for POPH before LT. Those with moderate POPH (mPAP >35 mm Hg), who improve with medical therapy, will benefit from LT. A transudative pleural effusion called hepatic hydrothorax (HH) is seen in 5-10% of people with cirrhosis. Refractory cases of HH benefit from LT. In recent years, increasing clinical expertise and advances in the medical field have resulted in better outcomes in patients with moderate to severe pulmonary disorders, who undergo LT.

The Danish comorbidity in liver transplant recipients study (DACOLT): a non-interventional prospective observational cohort study

Background

Liver transplantation is the only curative treatment for patients with end-stage liver disease. Short-term survival has improved due to improved surgical techniques and greater efficacy of immunosuppressive drugs. However, long-term survival has not improved to the same extent as the short-term survival, and the 10-year survival after liver transplantation is 60%. In addition to liver- and transplant-related causes, comorbidities such as cardiovascular, pulmonary, renal, and metabolic diseases have emerged as leading causes of morbidity and mortality in liver transplant recipients. The objective of this study is to assess the burden of comorbidities and identify both liver- and transplant-related risk factors as well as traditional risk factors that contribute to the pathogenesis of comorbidity in liver transplant recipients.

Methods/design

The Danish Comorbidity in Liver Transplant Recipients (DACOLT) study is an observational, longitudinal study. We aim to include all adult liver transplant recipients in Denmark (n = approx. 600). Participants will be matched by sex and age to controls from the Copenhagen General Population Study (CGPS) and the Copenhagen City Heart Study (CCHS). Physical and biological measures including blood pressure, ankle–brachial index, spirometry, exhaled nitric oxide, electrocardiogram, transthoracic echocardiography, computed tomography (CT) angiography of the heart, unenhanced CT of chest and abdomen and blood samples will be collected using uniform protocols in participants in DACOLT, CGPS, and CCHS. Blood samples will be collected and stored in a research biobank. Follow-up examinations at regular intervals up to 10 years of follow-up are planned.

Discussion

There is no international consensus standard for optimal clinical care or monitoring of liver transplant recipients. This study will determine prevalence, incidence and risk factors for comorbidity in liver transplant recipients and may be used to provide evidence for guidelines on management, treatment and screening and thereby contribute to improvement of the long-term survival.

Trial registration ClinicalTrials.gov: NCT04777032; date of registration: March 02, 2021.

Maternal hepatitis B virus and hepatitis C virus carrier status during pregnancy and long-term respiratory complications in the offspring

OBJECTIVE

Maternal HBV or HCV carrier status is a cause for concern regarding both the course of pregnancy and the short-term perinatal outcomes. Our main aim was to evaluate whether offspring born to carrier mothers during pregnancy, also suffer from long-term pediatric respiratory morbidity (until 18 years of age).

METHOD OF STUDY

A population-based cohort analysis was conducted at a single tertiary medical center. The study included all singleton deliveries between the years 1991-2014, comparing incidence of respiratory-related hospitalization of offspring born to mothers who were carrier of HBV or HCV during their pregnancy to those born to nonexposed mothers. Respiratory morbidities were based on a predefined set of ICD-9 codes. A Kaplan-Meier survival curve was used to compare cumulative hospitalization incidence between the groups and a Cox regression model was used to adjust for confounding variables.

RESULTS

During the study period, 242,342 deliveries met the inclusion criteria. Of them, 771 (0.31%) were to HBV or HCV mother carriers during pregnancy. A Kaplan-Meier curve demonstrated that children born to HBV or HCV carriers had higher cumulative incidence of respiratory morbidity (Log rank test p = 0.007). In the Cox regression model, while controlling for maternal age, diabetes mellitus, hypertensive disorders, caesarian section and gestational age at birth, maternal HBV or HCV carrier status was noted as an independent risk factor for long-term respiratory morbidity in the offspring (adjusted HR = 1.43, 95% CI 1.07-1.90, p = 0.015).

CONCLUSIONS

Maternal HBV or HCV carrier status in pregnancy may increase offspring susceptibility to long-term respiratory morbidity.

The ET-1-mediated carbonylation and degradation of ANXA1 induce inflammatory phenotype and proliferation of pulmonary artery smooth muscle cells in HPS

Hepatopulmonary syndrome (HPS) is a serious complication of advanced liver disease, which markedly increases mortality. Pulmonary vascular remodelling (PVR) induced by circulating mediators plays an important role in the pathogenesis of HPS, while the underlying mechanism remains undefined. In the present study, we reported that endothelin-1 (ET-1) is up-regulated and annexin A1(ANXA1) is down-regulated in HPS rat, and ET-1 decreases the ANXA1 expression in a dose-dependent manner in rat pulmonary arterial smooth muscle cells (PASMCs). Then, we showed that ANXA1 can decrease nuclear p-ERK1/2 accumulation and decrease the cyclin D1 expression, thus resulting in the subsequent inhibition of PASMCs proliferation. As previously reported, we confirmed that ET-1 decreases the ANXA1 protein levels by the carbonylation and degradation of ANXA1. In conclusion, our research links the signaling cascade of ET1-ANXA1-cell proliferation to a potential therapeutic strategy for blocking IPS-associated PVR.

The involvement of aquaporin 1 in the hepatopulmonary syndrome rat serum-induced migration of pulmonary arterial smooth muscle cells via the p38-MAPK pathway

Hepatopulmonary syndrome (HPS) is characterized by arterial oxygenation defects induced by intrapulmonary vascular dilation (IPVD). Pulmonary vascular remodeling (PVR) is an important pathological feature of IPVD; however, the details regarding the underlying mechanisms of this process remain undefined. Recent studies have determined that the abnormal migration of pulmonary arterial smooth muscle cells (PASMCs) plays a role in the pathogenesis of the PVR associated with HPS. Additionally, aquaporin 1 (AQP1) not only functions as a water channel molecule but also promotes cell migration by facilitating water transport in the lamellipodia of migrating cells. Common bile duct ligation (CBDL) rat is a well-accepted HPS model; we determined that the immunoperoxidase labeling of AQP1 was enhanced in the media of the pulmonary vessels in CBDL rats. HPS rat serum mediated the overexpression of AQP1 in PASMCs, and also upregulated PASMC migration. Small interfering RNAs (siRNAs) that targeted rat AQP1 caused significant downregulation of AQP1, which resulted in decreased PASMC migration. Furthermore, the inhibition of the p38-MAPK pathway abolished AQP1-dependent PASMC migration. In conclusion, this study demonstrated that AQP1 enhanced PASMC migration via the p38-MAPK pathway in rat with HPS and may represent a potential therapeutic strategy in the setting of pulmonary vascular remodeling associated with HPS.

Immunogenetics of Disease-Causing Inflammation in Sarcoidosis

Sarcoidosis is a systemic inflammatory disorder characterised by tissue infiltration by mononuclear phagocytes and lymphocytes with associated non-caseating granuloma formation. Originally described as a disorder of the skin, sarcoidosis can involve any organ with wide-ranging clinical manifestations and disease course. Recent studies have provided new insights into the mechanisms involved in disease pathobiology, and we now know that sarcoidosis has a clear genetic basis largely involving human leukocyte antigen (HLA) genes. In contrast to Mendelian-monogenic disorders--which are generally due to specific and relatively rare mutations often leading to a single amino acid change in an encoded protein--sarcoidosis results from genetic variations relatively common in the general population and involving multiple genes, each contributing an effect of varying magnitude. However, an individual may have the necessary genetic profile and yet the disease will not develop unless an environmental or infectious factor is encountered. Genetics appears also to contribute to the huge variability in clinical phenotype and disease behaviour. Moreover, it has been established that sarcoidosis granulomatous inflammation is a highly polarized T helper 1 immune response that starts with an antigenic stimulus followed by T cell activation via a classic HLA class II-mediated pathway. A complex network of lymphocytes, macrophages, and cytokines is pivotal in the orchestration and evolution of the granulomatous process. Despite these advances, the aetiology of sarcoidosis remains elusive and its pathogenesis incompletely understood. As such, there is an urgent need for a better understanding of disease pathogenesis, which hopefully will translate into the development of truly effective therapies.

Development of a murine model of early sepsis in diet-induced obesity

Sepsis, a global health issue, is the most common cause of mortality in the intensive care unit. The aim of this study was to develop a new model of sepsis that investigates the impact of prolonged western diet (WD) induced obesity on the response to early sepsis. Male C57BL/6 mice were fed either a high fat WD or normal chow diet (NCD) for 6, 15, or 27 weeks. Septic obese mice at 15 and 27 weeks had significantly lower levels of lung myeloperoxidase (26.3 ± 3.80 U/mg tissue) compared to age matched ad lib (44.1 ± 2.86 U/mg tissue) and diet restricted (63.2 ± 5.60 U/mg tissue) controls. Low levels of lung inflammation were not associated with changes in hepatic cytokines and oxidative stress levels. Obese mice had significantly (P < 0.0001) larger livers compared to controls. Histological examination of the livers demonstrated that WD fed mice had increased inflammation with pronounced fat infiltration, steatosis, and hepatocyte ballooning. Using this model of prolonged exposure to high fat diet we have data that agree with recent clinical observations suggesting obese individuals are protected from sepsis-induced lung injury. This model will allow us to investigate the links between damage to the hepatic microcirculation, immune response, and lung injury.

Pulmonary contraindications, indications and MELD exceptions for liver transplantation: a contemporary view and look forward

Pulmonary concerns in liver transplant candidates have intraoperative and outcome implications. Evolving MELD exception policies address transplant priority for problems such as hepatopulmonary syndrome, portopulmonary hypertension, and hemorrhagic hereditary telangiectasia. Other pulmonary issues such as refractory hepatic hydrothorax, advanced chronic obstructive lung disease (including alpha-1 antitrypsin deficiency) and indeterminate pulmonary nodules may affect liver transplant consideration. Herein, we discuss current pulmonary-related contraindications, indications and MELD exception policies for liver transplantation, suggesting future considerations.

Decline in pulmonary function during chronic hepatitis C virus therapy with modified interferon alfa and ribavirin

Rare interstitial lung disease cases have been reported with albinterferon alfa-2b (albIFN) and pegylated interferon alfa-2a (Peg-IFNα-2a) in chronic hepatitis C virus (HCV) patients. Systematic pulmonary function evaluation was conducted in a study of albIFN q4wk vs Peg-IFNα-2a qwk in patients with chronic HCV genotypes 2/3. Three hundred and ninety-one patients were randomly assigned 4:4:4:3 to one of four, open-label, 24-week treatment groups including oral ribavirin 800 mg/d: albIFN 900/1200/1500 μg q4wk or Peg-IFNα-2a 180 μg qwk. Standardized spirometry and diffusing capacity of the lung for carbon monoxide (DLCO) were recorded at baseline, weeks 12 and 24, and 6 months posttreatment, and chest X-rays (CXRs) at baseline and week 24. Baseline spirometry and DLCO were abnormal in 35 (13%) and 98 (26%) patients, respectively. Baseline interstitial CXR findings were rare (4 [1%]). During the study, clinically relevant DLCO declines (≥15%) were observed in 173 patients (48%), and were more frequent with Peg-IFNα-2a and albIFN 1500 μg; 24 weeks posttreatment, 57 patients (18%) still had significantly decreased DLCO, with a pattern for greater rates with albIFN vs Peg-IFNα-2a. One patient developed new interstitial CXR abnormalities, but there were no clinically relevant interstitial lung disease cases. The risk of persistent posttreatment DLCO decrease was not related to smoking, alcohol, HCV genotype, sustained virologic response, or baseline viral load or spirometry. Clinically relevant DLCO declines occurred frequently in chronic HCV patients receiving IFNα/ribavirin therapy and commonly persisted for ≥6 months posttherapy. The underlying mechanism and clinical implications for long-term pulmonary function impairment warrant further research.

Resolution of severe hepato-pulmonary syndrome following transjugular portosystemic shunt procedure

The hepato-pulmonary syndrome (HPS) is a relatively common complication of hepatic disease that leads to hypoxaemia and dyspnoea secondary to pulmonary shunting. A number of pharmacological therapies have been trialled, yet liver transplantation remains the only definitive treatment. The use of a transjugular intrahepatic portosystemic shunt (TIPS) to reduce portal hypertension and improve oxygenation remains controversial in HPS due to the lack of large clinical series or randomised controlled trials. We present a case of HPS successfully treated with TIPS and review the relevant literature.

Respiratory mechanics and lung tissue remodeling in a hepatopulmonary syndrome rat model

Intrapulmonary vasodilation is a hallmark of the hepatopulmonary syndrome (HPS). However, its effects on respiratory mechanical properties and lung morphology are unknown. To determine these effects, 28 rats were randomly divided to control and experimental HPS groups (eHPS). The spontaneous breathing pattern, gas exchange, respiratory system mechanical properties, and lung and liver morphology of the rats were evaluated. Tidal volume, minute ventilation and mean inspiratory flow were significantly reduced in the eHPS group. Chest wall pressure dissipation against the resistive and viscoelastic components and elastic elastance were increased in the eHPS group. The lung resistive pressure dissipation was lower but the viscoelastic pressure was higher in the eHPS group. The airway volume proportion of collagen and elastic fibers was increased in the eHPS animals (16% and 51.7%; P<0.05 and P<0.001, respectively). The proportion of collagen volume in the vasculature increased 29% in the eHPS animals (P<0.01). HPS presents with respiratory system mechanical disarray as well as airway and vascular remodeling.

Determinants of elevated healthcare utilization in patients with COPD

BACKGROUND

Chronic obstructive pulmonary disease (COPD) imparts a substantial economic burden on western health systems. Our objective was to analyze the determinants of elevated healthcare utilization among patients with COPD in a single-payer health system.

METHODS

Three-hundred eighty-nine adults with COPD were matched 1:3 to controls by age, gender and area of residency. Total healthcare cost 5 years prior recruitment and presence of comorbidities were obtained from a computerized database. Health related quality of life (HRQoL) indices were obtained using validated questionnaires among a subsample of 177 patients.

RESULTS

Healthcare utilization was 3.4-fold higher among COPD patients compared with controls (p < 0.001). The "most-costly" upper 25% of COPD patients (n = 98) consumed 63% of all costs. Multivariate analysis revealed that independent determinants of being in the "most costly" group were (OR; 95% CI): age-adjusted Charlson Comorbidity Index (1.09; 1.01-1.2), history of: myocardial infarct (2.87; 1.5-5.5), congestive heart failure (3.52; 1.9-6.4), mild liver disease (3.83; 1.3-11.2) and diabetes (2.02; 1.1-3.6). Bivariate analysis revealed that cost increased as HRQoL declined and severity of airflow obstruction increased but these were not independent determinants in a multivariate analysis.

CONCLUSION

Comorbidity burden determines elevated utilization for COPD patients. Decision makers should prioritize scarce health care resources to a better care management of the "most costly" patients.

Albinterferon Alfa-2b was not inferior to pegylated interferon-α in a randomized trial of patients with chronic hepatitis C virus genotype 2 or 3

BACKGROUND & AIMS

A phase 3 active-controlled study was conducted to assess the efficacy/safety of albinterferon alfa-2b (albIFN), a novel, long-acting, genetic fusion polypeptide of recombinant human albumin and interferon alfa-2b, in patients with chronic hepatitis C virus (HCV) genotype 2/3.

METHODS

In all, 933 patients were randomized to open-label subcutaneous treatment with pegylated interferon-alfa-2a (Peg-IFNalfa-2a) 180 μg/wk, or albIFN 900 or 1200 μg every 2 weeks for 24 weeks, each administered with oral ribavirin 800 mg/day. The primary end point of the study was sustained virologic response (SVR) (HCV-RNA level, <15 IU/mL at week 48). During the study, the data monitoring committee recommended dose modification for all patients receiving albIFN 1200 μg to 900 μg, impacting 38% of this treatment arm.

RESULTS

By intention-to-treat analysis, SVR rates were 84.8% (95% confidence interval, 80.4%-88.6%), 79.8% (95% confidence interval, 74.9%-84.1%), and 80.0% (95% confidence interval, 75.1%-84.3%) with Peg-IFNalfa-2a, and albIFN 900 and 1200 μg, respectively. The primary hypothesis of noninferiority of SVR was established for albIFN 900 μg (P = .009) and 1200 μg (P = .006). Independent positive predictors of SVR by multivariate regression analysis were pretreatment HCV-RNA level less than 400,000 IU/mL, age younger than 45 years, body mass index less than 30 kg/m(2), genotype 2, normal γ-glutamyl transpeptidase and increased alanine aminotransferase levels at baseline, fibrosis stage F0-F2, no steatosis, and Asian geographic region (Peg-IFNalfa-2a only). The 3 treatment groups showed similar rates of serious (7%-8%) and severe (13%-16%) adverse events, and discontinuations owing to adverse events (3.6%-5.5%).

CONCLUSION

Albinterferon alfa-2b 900 μg every 2 weeks provides an alternative efficacious treatment option in patients with chronic HCV genotype 2 or 3.