HISTOLOGICAL AND ULTRASTRUCTURAL ADAPTATION OF THE LIVER TO EXERCISE, DIETARY PATTERN AND ENVIRONMENTAL STRESSORS: A NARRATIVE REVIEW

Background: The liver is a highly plastic organ, remodeling at the histological and ultrastructural level in response to physiological and environmental demands. Exercise, dietary pattern and environmental stressors are all known to modify liver structure but are usually studied separately and from a metabolic rather than a histomorphological perspective.
Aims: This narrative review brings together and critically compares recent evidence (2022-2026) on liver histological and ultrastructural adaptation across these three-exposure area, contradiction, identifying shared mechanism and knowledge gaps.
Findings: The same factors were repeated in all three areas: lipid handling, oxidative balance, mitochondrial function and zonal susceptibility. Together they made a common, mostly non-specific pattern of liver damage including inflammation, steatosis and hepatocyte degeneration. The difference was mainly in the direction of the effect. Exercise protected the liver while dietary excess and environmental toxicants damaged it. The effects reported were also highly dose- and species-dependent, as illustrated by the contrasting responses of the liver to fructose in rodent’s vs larger animals. A limitation that pervades much of this research is that whereas animal studies can directly examine the liver using histology, human studies must depend on non-invasive surrogate measures.
Conclusion: Recognizing the mechanistic convergence across exposure, addressing biological sex and combined exposure and adopting emerging digital pathology and spatial omics approaches are priorities for advancing a currently fragmented field.