Blood Biomarkers for Early MASH Diagnosis

Abstract

Metabolic dysfunction-associated steatohepatitis (MASH), previously known as nonalcoholic steatohepatitis (NASH), represents an advanced stage of metabolic dysfunction-associated steatotic liver disease (MASLD) and poses a significant global health burden. Early diagnosis is paramount for implementing interventions that can halt or reverse disease progression. Blood-based biomarkers offer a promising, non-invasive alternative to traditional liver biopsy, facilitating timely detection and risk stratification. This review provides a comprehensive analysis of current and emerging blood biomarkers for early MASH diagnosis, encompassing their pathophysiological basis, clinical utility, limitations, and integration into clinical practice, while highlighting recent research and guideline recommendations.

Introduction

MASH is a progressive inflammatory liver condition characterized by steatosis, hepatocellular ballooning, and lobular inflammation in the context of metabolic dysfunction. The disease is closely linked to obesity, type 2 diabetes, and other features of metabolic syndrome. Given the asymptomatic nature of early MASH and the invasive risks of liver biopsy, there is a compelling need for accurate, sensitive, and easily accessible blood biomarkers. This article aims to synthesize the latest evidence on blood-based diagnostic tools for early MASH detection, focusing on their mechanistic relevance, clinical applicability, and potential to transform hepatology practice.

Epidemiology / Disease Burden

MASH affects approximately 1.5–6.5% of the global adult population, with higher prevalence in individuals with obesity or diabetes. The increasing incidence of metabolic syndrome has paralleled a rise in MASH cases, contributing to significant morbidity, healthcare utilization, and economic burden. As MASH can progress to cirrhosis, liver failure, and hepatocellular carcinoma, early detection is essential for disease interception and improving long-term outcomes.

Pathophysiology

The pathogenesis of MASH involves a complex interplay of insulin resistance, lipid accumulation, oxidative stress, mitochondrial dysfunction, and inflammatory cascades. Hepatocellular injury triggers the release of various molecules into the circulation, including cytokeratin-18 fragments, inflammatory cytokines, and extracellular vesicles. These components form the mechanistic basis for blood biomarker development, reflecting ongoing hepatocyte apoptosis, necrosis, and fibrosis in real-time.

Risk Factors

Major risk factors for MASH include central obesity, type 2 diabetes mellitus, dyslipidemia, hypertension, advanced age, and genetic predispositions (e.g., PNPLA3, TM6SF2 variants). Lifestyle factors such as sedentary behavior and excess caloric intake further exacerbate the risk. Recognizing these risk factors is crucial for targeted screening using blood biomarkers in high-risk populations.

Clinical Features

Early-stage MASH is frequently asymptomatic or presents with non-specific symptoms such as fatigue and malaise. Hepatomegaly may be detected on physical examination, but overt clinical manifestations are uncommon until advanced fibrosis develops. Consequently, reliance on clinical features alone for early detection is inadequate, necessitating sensitive laboratory-based approaches.

Diagnosis

Liver biopsy remains the gold standard for MASH diagnosis and staging but is limited by invasiveness, sampling error, and patient reluctance. Blood biomarkers have emerged as valuable adjuncts, offering a non-invasive, repeatable means of disease assessment. Key biomarkers include:

1. Cytokeratin-18 (CK-18) Fragments: Elevated levels of CK-18, released during hepatocyte apoptosis, correlate with histological MASH and are among the most studied biomarkers. Both M30 (apoptosis) and M65 (total cell death) fragments show promise, though cutoff values and standardization remain challenges.

2. Enhanced Liver Fibrosis (ELF) Test: This panel assesses fibrosis-related proteins (hyaluronic acid, PIIINP, TIMP-1) and has demonstrated good correlation with advanced MASH in multiple cohorts.

3. Pro-inflammatory and Metabolic Markers: Elevated levels of TNF-α, IL-6, and adipokines (adiponectin, leptin) reflect underlying inflammation and metabolic dysfunction. However, specificity for MASH is limited due to overlap with other systemic conditions.

4. MicroRNAs and Extracellular Vesicles: Emerging evidence supports roles for circulating microRNAs (e.g., miR-122, miR-34a) and exosome-derived markers as sensitive indicators of early hepatocellular injury.

Combining multiple biomarkers into scoring systems, such as the NAFLD fibrosis score and FIB-4, enhances diagnostic accuracy and risk stratification in clinical practice.

Treatment & Management

Although no blood biomarker currently replaces histological assessment for definitive MASH diagnosis, integrating biomarker testing with clinical and imaging data enables earlier detection and monitoring. Management centers on lifestyle modification diet, exercise, and weight loss which can reverse early disease. Pharmacotherapy (e.g., GLP-1 agonists, pioglitazone, vitamin E) is reserved for selected patients with biopsy-confirmed MASH and significant fibrosis. Serial measurement of blood biomarkers may assist in tracking disease trajectory and therapeutic response.

Recent Advances / Emerging Therapies

Recent advances include the development of novel biomarker panels incorporating machine learning algorithms and multi-omics data, improving sensitivity and specificity for early MASH. Ongoing trials are evaluating the utility of metabolites, proteomic signatures, and immune cell profiling as adjunct diagnostic tools. Additionally, next-generation sequencing and high-throughput platforms are accelerating biomarker discovery and validation.

Guideline Recommendations

International guidelines such as those from EASL and AASLD advocate for the use of non-invasive biomarkers and scoring systems to identify patients at risk for advanced fibrosis and MASH in at-risk populations. While none recommend a single biomarker for standalone diagnosis, combining blood biomarkers with elastography or imaging is endorsed for screening and longitudinal monitoring. Guidelines also emphasize the importance of context-driven interpretation, considering comorbidities and pre-test probability.

Conclusion

Blood biomarkers represent a pivotal advancement in the early diagnosis of MASH, offering non-invasive, scalable, and clinically informative alternatives to liver biopsy. While current biomarkers such as CK-18 and the ELF test have demonstrated utility, ongoing research into multi-analyte panels and novel molecular signatures holds promise for further improving diagnostic accuracy. Integration of blood biomarkers into routine care, guided by current recommendations and emerging evidence, will facilitate timely intervention, risk stratification, and ultimately improved patient outcomes in MASH.