New Non-invasive Biomarkers of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD)

Inclusion Criteria for Participants with MASLD: * Presence of liver steatosis (detected either by hepatic ultrasonography/CAP/histologically) or MASH/simple steatosis confirmed by liver biopsy * Absence of secondary causes of fat accumulation in the liver and other liver disease: ruled out other etiologies of liver disease, such as viral hepatitis, drug-induced liver disease, autoimmune liver disease, biliary tract disease, and hereditary metabolic diseases Inclusion Criteria for Negative Controls: * Absence of liver disease * For breath analysis: absence of liver steatosis (normal liver ultrasound image and CAP less than 248 dB/m) * For plasma spectroscopy and bile acid analysis: Body Mass Index ≤ 25 and waist-hip ratio ≤ 0.95 plus normal liver ultrasound * Absence of diabetes mellitus and metabolic syndrome * Normal liver function tests, lipid spectrum, fasting glycemia * Alcohol intake less than 20 g/ day (women) or 30 g/ day (men) Exclusion Criteria: * Non-compliance with the investigation program * Failure to sign the informed consent form * Liver biopsy/clinic discrepancy * For LMN a TMA "stress test": fish, see fruit and citrus fruit allergy * Pregnancy * For bile acid analysis: Treatment with BA or BA sequestrants * For bile acid analysis: Portal hypertension (does not apply for MASH patients) * For bile acid analysis: Cirrhosis (does not apply for MASH patients) * For plasma spectroscopy: Cirrhosis * Anamnesis of alcohol abuse (based on GGT, carbohydrate-deficie…