In patients with severe obesity undergoing two-stage bariatric surgery, picrosirius-red-measured pericellular fibrosis in abdominal fat showed no baseline association with MASLD features, steatohepatitis or liver fibrosis, and changes in liver histology were unrelated to changes in fat fibrosis. Omental fibrosis fell after weight loss (0.41 to 0.32 µm²/cell, p<0.005); subcutaneous fibrosis did not, though ECM-remodeling and inflammatory transcripts dropped in subcutaneous fat at one year. Higher subcutaneous fibrosis predicted smaller weight and BMI loss, while rising omental fibrosis tracked with worsening hepatic fibrosis.
The headline result is largely a null: the popular idea that stiff, scarred fat drives fatty liver disease gets little support here, which tempers enthusiasm for fibrosis as a liver-risk marker. The more interesting signal is that subcutaneous fibrosis may mark people who respond poorly to surgery, a hypothesis consistent with fibrotic fat resisting expansion and shrinkage. Practically, this cannot guide patients today: the measure requires a fat biopsy, and the cohort is small, surgical and highly selected, so the findings do not extend to people losing weight by diet, exercise or GLP-1 drugs. Correlations with p-values just under 0.05 across multiple tests warrant caution, and the omental-fibrosis-to-liver link may reflect chance. This work is a preprint and has not been peer reviewed, so results may shift. Overall it is incremental, refining mechanistic ideas about adipose tissue rather than changing clinical practice.