Altered profiles of circulating cytokines in chronic liver diseases (NAFLD/HCC): Impact of the PNPLA3I148M risk allele

Relation of 91 Circulating Inflammatory Proteins to Nonalcoholic Fatty Liver Disease: A Two-Sample Mendelian Randomisation Study

Increasingly, emerging research evidence has demonstrated that nonalcoholic fatty liver disease (NAFLD) is a disease closely associated with systemic inflammation. However, the specific upstream inflammatory factors engaged in the pathogenesis of NAFLD remain unclear. Our study aimed to identify the inflammatory regulators causally associated with NAFLD pathogenesis through Mendelian randomisation. A two-sample Mendelian randomisation method was applied to analyse the causal association between 91 circulating inflammatory proteins and NAFLD. Data on circulating inflammatory proteins were derived from samples of European ancestry (14,824 samples) and NAFLD data were obtained from the FinnGen consortium (2025 cases and 284,826 controls). Instrumental variables were selected from the genetic variance and F-statistics were calculated to avoid bias. We adopted the random-effects inverse variance weighting (IVW) method as our primary analytical approach. Supplementary analyses were also implemented, including weighted median, MR-Egger and weighted mode. Moreover, we conducted pleiotropy and heterogeneity analyses to validate the accuracy of the findings. The application of Mendelian randomisation analysis identified four inflammatory factors that might be causally associated with NAFLD at the genetic level. Elevated levels of eotaxin (or = 1.27, 95% CI: 1.05-1.53, p = 0.014), osteoprotegerin (OPG) (or = 1.29, 1.03-1.60, p = 0.023) and TNFRSF9 (or = 1.32, 95% CI: 1.06-1.64, p = 0.014) may be causally related to an increasing risk of NAFLD. Conversely, heightened leukaemia inhibitory factor (LIF) levels (or = 0.63, 0.44-0.92, p = 0.016) were linked to a lower risk of NAFLD onset. There was no causal relationship between levels of other circulating inflammatory proteins and NAFLD. Our analysis uncovered four upstream inflammatory factors genetically associated with the pathogenesis of NAFLD. These results highlight the potential involvement of inflammation in NAFLD, which provides partial insights for further research in this field in the future.

Comparison of wild-type and high-risk PNPLA3 variants in a human biomimetic liver microphysiology system for metabolic dysfunction-associated steatotic liver disease precision therapy

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors, including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges in developing MASLD therapeutics, creating patient cohorts for clinical trials, and optimizing therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 (I148M variant) in primary hepatocytes as it is associated with MASLD progression. We constructed the LAMPS with genotyped wild-type and variant PNPLA3 hepatocytes, together with key non-parenchymal cells, and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune-activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS), and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study, using primary cells, serves as a benchmark for studies using "patient biomimetic twins" constructed with patient induced pluripotent stem cell (iPSC)-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation, and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to the wild-type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in the PNPLA3 wild-type CC LAMPS compared to the GG variant in multiple MASLD metrics, including steatosis, stellate cell activation, and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.

Comparison of Wild-Type and High-risk PNPLA3 variants in a Human Biomimetic Liver Microphysiology System for Metabolic Dysfunction-associated Steatotic Liver Disease Precision Therapy

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges for developing MASLD therapeutics, creation of patient cohorts for clinical trials and optimization of therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant PNPLA3 rs738409 (I148M variant) in primary hepatocytes, as it is associated with MASLD progression. We constructed LAMPS with genotyped wild type and variant PNPLA3 hepatocytes together with key non-parenchymal cells and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS) and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study using primary cells serves as a benchmark for studies using patient biomimetic twins constructed with patient iPSC-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to wild type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in PNPLA3 wild type CC LAMPS compared to the GG variant in multiple MASLD metrics including steatosis, stellate cell activation and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.

Inflammatory Protein Signatures as Predictive Disease-Specific Markers for Non-Alcoholic Steatohepatitis (NASH)

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic disease worldwide, consisting of a broad spectrum of diseases such as simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. Hepatic inflammation plays a key role in the pathophysiology of NAFLD. Inflammatory mediators such as cytokines and chemokines are considered as contributing factors to NAFLD development and progression. In the present study, we aimed to investigate the inflammatory protein signatures as predictive disease-specific markers for non-alcoholic fatty liver disease (NAFLD). This cross-sectional study included healthy control (n = 64), NAFL (n = 109), and NASH (n = 60) human subjects. Serum concentrations of various cytokines and chemokines were evaluated using sensitive multiplex assays. We used principal component analysis (PCoA) to reveal distinct differences in the levels of cytokines and chemokines between each of the study groups. Further, a random forest classification model was developed to identify the panel of markers that could predict diseases. The protein-protein network analysis was performed to determine the various signaling pathways associated with the disease-specific panel of markers. Serum concentrations of TNF-α, IL-1β, IL-1ra, G-CSF, PDGF-BB, MCP-1, MIP-1a, MIP-1b, RANTES, eotaxin, IL-8 and IP-10 were significantly increased in NASH group as compared to control group. Furthermore, serum concentrations of IL-9 and IL-13 were significantly lower in the NASH group, whereas IL-2 levels were significantly decreased in the NAFL group when compared to the control group. PCoA results demonstrated statistically significant differences in cytokines and chemokines between each of the study groups (PERMANOVA p = 0.001; R2 = 0.102). RANTES, IL-1ra, MIP-1b, IL-2, and G-CSF could differentiate the NAFL group from the controls; G-CSF, IL-1ra, TNF-α, RANTES, and IL-9 could differentiate the NASH group from the controls; and G-CSF, IL-9, IL-13, eotaxin, and TNF- α could differentiate the NASH group from the NAFL group. Our protein-protein network revealed that these markers are involved in cytokine-cytokine receptor interaction, Th1 and Th2 cell differentiation, TNF, chemokine, JAK/STAT, P13K/Akt, TLR, NOD-like receptor, NF-kB, and adipocytokine signaling pathways which might be responsible for disease pathogenesis. Our study findings revealed a set of distinct cytokine and chemokine markers and they might be considered as biomarkers in distinguishing NASH from NAFL. Future multicentre studies with larger sample size are recommended to determine the potential utility of these panels of markers.

Cryptogenic non-cirrhotic HCC: Clinical, prognostic and immunologic aspects of an emerging HCC etiology

The incidence of hepatocellular carcinoma (HCC) in non-cirrhotic livers is rising significantly, but clear risk factors for screening remain elusive. This study sought to characterize non-cirrhotic HCC etiologies. HCC cases from 2009 to 2020 in a Dutch referral center were examined, revealing 371 out of 1654 cases (22%) as non-cirrhotic. Notably, the incidence of non-cirrhotic HCC increased by 61% in the time frame between 2009 and 2020. Interestingly 39% of non-cirrhotic HCC cases had cryptogenic origins. Cryptogenic non-cirrhotic HCC exhibited similarities with non-cirrhotic NAFLD HCC, but displayed advanced tumor stages, lower surgical rates, and a more frequent presence of symptoms, which substantiated in poor survival rates. Advanced cryptogenic non-cirrhotic HCC stages exhibited elevated serum interleukin-6 levels compared to non-cirrhotic HCC with defined etiologies. Comparative analysis encompassing cryptogenic and NAFLD non-cirrhotic HCC cohorts and controls unveiled comparable circulating immune biomarker profiles and PNPLA3 polymorphisms. To conclude, the primary etiology of non-cirrhotic HCC in our cohort has not defined risk factors. This cryptogenic variant exhibits distinct traits, such as advanced tumors and increased symptoms, and most resemble burned-out NAFLD. Understanding this HCC variant is crucial for improving screening and management strategies.