Crosstalk between Irisin Levels, Liver Fibrogenesis and Liver Damage in Non-Obese, Non-Diabetic Individuals with Non-Alcoholic Fatty Liver Disease

BACKGROUND

Insulin resistance plays a relevant role in the onset of non-alcoholic fatty liver disease (NAFLD) and its progression to non-alcoholic steatohepatitis (NASH) and fibrosis. Irisin is an exercise-induced myokine involved in the regulation of energy homeostasis and glucose metabolism. Additionally, pre-clinical models have shown a potential role of irisin in the pathogenesis of NAFLD. The aim of this study is to explore the association between irisin, histological features and biomarkers of liver fibrogenesis in non-diabetic, non-obese, biopsy-proven NAFLD individuals.

METHODS

Forty-one patients with histological evidence of NAFLD were included. Circulating irisin and direct markers of fibrogenesis N-terminal type III collagen propeptide (PRO-C3) and type VI collagen cleavage product (PRO-C6) were measured by ELISA.

RESULTS

Median age of the cohort was 45 years (41-51) and 80.4% were male. Significant fibrosis (stage ≥ 2) was present in 36.6% of cases. Circulating irisin, PRO-C3 and PRO-C6 levels were significantly higher in subjects with fibrosis stage ≥ 2 when compared to those with fibrosis stage < 2 (5.96 ng/mL (95% CI = 4.42-9.19) vs. 2.42 ng/mL (95% CI = 1.73-5.95), p = 0.033; 9.5 ng/mL (95% CI = 7.7-13.6) vs. 6.2 ng/mL (95% CI = 4.9-8.9), p = 0.016; 6.6 ng/mL (95% CI = 5.6-7.9) vs. 5.1 ng/mL (95% CI = 4.2-5.4), p = 0.013, respectively). Irisin levels were similarly distributed between the features of NASH. Circulating irisin positively correlated with both PRO-C3 and PRO-C6 levels (r = 0.47, p = 0.008 and r = 0.46, p = 0.002).

CONCLUSIONS

Increased circulating irisin levels may identify a more aggressive phenotype of liver disease with increased fibrogenesis and more severe liver damage.

Serum and Urine Biomarkers Related to Kidney Fibrosis Predict Kidney Outcome in Czech Patients with IgA Nephropathy

We evaluated biomarkers related to kidney fibrosis for the outcome of patients with IgA nephropathy (IgAN). Clinical parameters (estimated glomerular filtration rate, hypertension, proteinuria) and histological findings were assessed in 134 patients with IgAN at the time of diagnosis and followed up prospectively (mean follow-up time, 56.5 months). We measured biomarkers of collagen and laminin turnover in serum and urine collected at the time of kidney biopsy using a novel enzyme-linked immunosorbent assay. Linear discriminant analysis and logistic regression models were used to predict the patient's kidney outcome. Five serum and urine biomarkers of laminin and collagen turnover (sLG1M, sPRO-C3, sPRO-C6, uPRO-C6/Cr, uC3M/Cr) could significantly differentiae IgAN patients with a worse prognosis. Clinical parameters (glomerular filtration rate (GFR), proteinuria) distinguished patients at risk of IgAN progression with a specificity of 87.3% and a sensitivity of 45.2% (area under the curve-AUC 0.751). The addition of the biomarkers significantly increased the prognostic ability with a specificity of 85.1% and a sensitivity of 73.3% (AUC 0.905). We have identified three serum (sLG1M, sPRO-C3, sPRO-C6) and two urinary markers (uPRO-C6/Cr, u-C3M /Cr) that significantly improve the prognostic ability of markers of kidney function to identify an IgAN patient's risk of progressing to ESKD.

Emerging concepts in the detection of liver fibrosis in non-alcoholic fatty liver disease

INTRODUCTION

The non-invasive identification of liver fibrosis related to Non-Alcoholic Fatty Liver Disease is crucial for risk-stratification of patients. Currently, the reference standard to stage hepatic fibrosis relies on liver biopsy, but multiple approaches are developed to allow for non-invasive diagnosis and risk stratification. Non-invasive tests, including blood-based scores and vibration-controlled transient elastography, have been widely validated and represent a good surrogate for risk stratification according to recent European and American guidelines.

AREAS COVERED

Novel approaches are based on 'liquid' biomarkers of liver fibrogenesis, including collagen-derived markers (PRO-C3 or PRO-C6), or 'multi-omics' technologies (e.g. proteomic-based molecules or miRNA testing), bearing the advantage of tailoring the intrahepatic disease activity. Alternative approaches are based on 'dry' biomarkers, including magnetic resonance-based tools (including proton density fat fraction, magnetic resonance elastography, or corrected T1), which reach similar accuracy of liver histology and will potentially help identify the best candidates for pharmacological treatment of fibrosing non-alcoholic steatohepatitis.

EXPERT OPINION

In the near future, the sequential use of non-invasive tests, as well as the complimentary use of liquid and dry biomarkers according to the clinical need (diagnosis, risk stratification, and prognosis, or treatment response) will guide and improve the management of this liver disease.

The fibroblast hormone Endotrophin is a biomarker of mortality in chronic diseases

Fibrosis, driven by fibroblast activities, is an important contributor to morbidity and mortality in most chronic diseases. Endotrophin, a signaling molecule derived from processing of type VI collagen by highly activated fibroblasts, is involved in fibrotic tissue remodeling. Circulating levels of endotrophin have been associated with an increased risk of mortality in multiple chronic diseases. We conducted a systematic literature review collecting evidence from original papers published between 2012 and January 2023 that reported associations between circulating endotrophin (PROC6) and mortality. Cohorts with data available to the study authors were included in an Individual Patient Data (IPD) meta-analysis that evaluated the association of PROC6 with mortality (PROSPERO registration number: CRD42023340215) after adjustment for age, sex and BMI, where available. In the IPD meta-analysis including sixteen cohorts of patients with different non-communicable chronic diseases (NCCDs) (N = 15,205) the estimated summary hazard ratio for 3-years all-cause mortality was 2.10 (95 % CI 1.75-2.52) for a 2-fold increase in PROC6, with some heterogeneity observed between the studies (I2=70 %). This meta-analysis is the first study documenting that fibroblast activities, as quantified by circulating endotrophin, are independently associated with mortality across a broad range of NCCDs. This indicates that, irrespective of disease, interstitial tissue remodeling, and consequently fibroblast activities, has a central role in adverse clinical outcomes, and should be considered with urgency from drug developers as a target to treat.

Circulating levels of endotrophin and cross-linked type III collagen reflect liver fibrosis in people with HIV

BACKGROUND AND AIMS

Liver-associated complications still frequently lead to mortality in people with HIV (PWH), even though combined antiretroviral treatment (cART) has significantly improved overall survival. The quantification of circulating collagen fragments released during collagen formation and degradation correlate with the turnover of extracellular matrix (ECM) in liver disease. Here, we analysed the levels of ECM turnover markers PC3X, PRO-C5, and PRO-C6 in PWH and correlated these with hepatic fibrosis and steatosis.

METHODS

This monocentre, retrospective study included 141 PWH. Liver stiffness and liver fat content were determined using transient elastography (Fibroscan) with integrated CAP function. Serum levels of formation of cross-linked type III collagen (PC3X), formation of type V collagen (PRO-C5) and formation type VI collagen (PRO-C6), also known as the hormone endotrophin, were measured with ELISA.

RESULTS

Twenty-five (17.7%) of 141 PWH had clinical significant fibrosis with liver stiffness ≥ 7.1 kPa, and 62 PWH (44.0%) had steatosis with a CAP value > 238 dB/m. Study participants with fibrosis were older (p = 0.004) and had higher levels of AST (p = 0.037) and lower number of thrombocytes compared to individuals without fibrosis (p = 0.0001). PC3X and PRO-C6 were markedly elevated in PWH with fibrosis. Multivariable cox regression analysis confirmed PC3X as independently associated with hepatic fibrosis. PRO-C5 was significantly elevated in participants with presence of hepatic steatosis.

CONCLUSION

Serological levels of cross-linked type III collagen formation and endotrophin were significantly associated with liver fibrosis in PWH receiving cART and thus may be suitable as a non-invasive evaluation of liver fibrosis in HIV disease.