Are elevated ALT/AST and low adiponectin characteristic markers of MASLD?

In metabolic dysfunction–associated steatotic liver disease (MASLD), the accumulation of liver fat and the subsequent development of inflammation are deeply linked to specific biochemical signatures, including elevated transaminases and suppressed adipokine levels.

Clinical and effectiveness evidence

In clinical practice, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serve as primary indicators of hepatocyte injury associated with MASLD.

• Enzyme Correlation: Large-scale cross-sectional studies confirm that elevated ALT and AST levels are frequently found in patients with metabolic liver disease. These enzymes are released into the bloodstream as liver cell membranes become permeable due to lipotoxic stress.
• Adiponectin Trends: Clinical data show a significant inverse relationship between circulating adiponectin and liver fat. Systematic reviews indicate that patients with MASLD have markedly lower adiponectin levels compared to healthy controls, with the lowest levels observed in those who have progressed to metabolic dysfunction–associated steatohepatitis (MASH) and advanced fibrosis.
• Treatment Response: Research on interventions such as SGLT2 inhibitors and specific polyphenols shows that reductions in hepatic fat content are directly mirrored by improvements in serum transaminase levels.

Mechanistic explanations

The relationship between these markers is driven by the adipose-liver axis and metabolic signaling pathways:

• Lipotoxicity and Enzyme Leakage: In the context of insulin resistance, the liver undergoes excessive de novo lipogenesis. This results in the accumulation of toxic lipid species (such as saturated free fatty acids), which trigger endoplasmic reticulum (ER) stress and oxidative damage. This injury causes hepatocytes to "balloon" or undergo apoptosis, leaking ALT and AST into the circulation.
• The Adiponectin-AMPK Pathway: Adiponectin normally functions as an anti-inflammatory and insulin-sensitizing hormone. It activates the AMP-activated protein kinase (AMPK) pathway, which promotes fatty acid oxidation and inhibits fat synthesis. In MASLD, "hypoadiponectinemia" (low adiponectin) occurs, leading to impaired AMPK signaling. This failure allows for unchecked fat accumulation and loses the suppressive effect on pro-inflammatory cytokines like TNF-alpha, accelerating liver inflammation.

Considerations for older adults

For a 74-year-old male, these associations remain highly relevant, though enzyme interpretation requires nuance. While the fundamental pathophysiology of MASLD persists in older age, absolute ALT levels may sometimes appear lower due to reduced hepatic mass or age-related metabolic shifts. However, the risk for advanced fibrosis increases with age, making the monitoring of these markers critical even if they fall within the "high-normal" range.

Bottom line

The claim is robustly supported: elevated ALT/AST and low adiponectin are hallmark markers of MASLD. Low adiponectin acts as a mechanistic driver of fat accumulation, while elevated transaminases reflect the resulting cellular injury and inflammation.