Splanchnic lipolysis in human obesity.
Level 4 - case-series / case-control
Cross-sectional physiological study comparing regional fatty acid kinetics across body composition phenotypes.
PubMed 15173884 · doi:10.1172/JCI21047
What was done
Systemic, splanchnic, and leg free fatty acid (FFA) kinetics were measured using isotope dilution and hepatic vein catheterization techniques across 68 adults. The cohort comprised 24 obese women, 20 obese men spanning a range of obesity phenotypes, 12 healthy lean women, and 12 healthy lean men. The primary aim was to quantify the relative contribution of splanchnic lipolysis to hepatic FFA delivery.
What was found
Plasma FFA concentrations were approximately 20% higher in obese men and women compared with lean controls. Splanchnic lipolysis contribution to hepatic FFA delivery ranged from less than 10% to almost 50%, correlating positively with visceral fat mass in women (r = 0.49, P = 0.002) and men (r = 0.52, P = 0.002). The slope relating visceral fat to splanchnic FFA contribution was significantly greater in women than in men (P < 0.05). Both splanchnic and leg tissues accounted for a higher proportion of systemic FFA release in obese participants than in lean controls.
Why it matters
This study provides direct human catheterization evidence that visceral adiposity substantially increases hepatic FFA exposure via portal/splanchnic lipolysis, with sex-specific differences in the magnitude of this effect.
Limits
The study is cross-sectional and cannot establish causal progression of metabolic disease. Sample size is modest (n = 68 total across four subgroups), and splanchnic measurements reflect the entire splanchnic bed rather than isolated omental versus mesenteric depots.
Cited by
- context The primary origin of fat in fatty liver disease is the spillover of free fatty acids from fat cells, particularly visceral fat.