Changes in Lipoprotein Fractions and Lipoprotein-Associated Alpha-Tocopherol After Sleeve Gastrectomy in Patients With Severe Obesity.

BACKGROUND

Sleeve gastrectomy (SG) improves obesity-related metabolic abnormalities, including dyslipidemia. However, postoperative changes in individual lipoprotein fractions and lipoprotein-associated antioxidants remain incompletely understood. This exploratory study aimed to characterize changes in serum lipoprotein fraction profiles after SG in Japanese patients with severe obesity using anion-exchange high-performance liquid chromatography (AEX-HPLC).

METHODS

Patients who underwent SG at Ohama Daiichi Hospital between July and December 2020 were enrolled. Clinical data and serum samples were obtained before and after surgery. Serum low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) were measured by enzymatic assays, and small dense LDL-C (sdLDL-C) was estimated using Sampson's equation. Lipoprotein fractions were evaluated by AEX-HPLC. α-tocopherol concentrations in HDL, LDL, and very low-density lipoprotein (VLDL) fractions were measured by reverse-phase high-performance liquid chromatography. Overall changes over time were assessed using the Friedman test, followed by post hoc Wilcoxon signed-rank tests with Benjamini-Hochberg false discovery rate adjustment.

RESULTS

Of 20 patients who underwent SG, 12 were analyzed after excluding eight with inadequate stored serum quality. Mean age and body mass index were 45.3 ± 10.5 years and 43.4 ± 5.9 kg/m2, respectively. SG significantly reduced body weight, hemoglobin A1c, and enzymatically measured TG, while HDL-C increased significantly. No significant changes were observed in LDL-C or non-HDL-C. Estimated sdLDL-C levels and the sdLDL-C/LDL-C ratio decreased significantly after SG. AEX-HPLC revealed significant increases in HDL and LDL fractions and a significant decrease in the VLDL fraction. α-Tocopherol content in HDL and LDL fractions increased significantly after SG, whereas no significant changes were observed in α-tocopherol-LDL/LDL or α-tocopherol-HDL/HDL. In contrast, α-tocopherol-VLDL/VLDL increased significantly after SG.

CONCLUSIONS

SG was associated with improvements in body weight and conventional lipid parameters, including reduced TG and increased HDL-C, together with a reduction in estimated sdLDL-C, in Japanese patients with severe obesity. AEX-HPLC revealed complex postoperative changes in lipoprotein fractions, including reduced VLDL and increased HDL and LDL fractions. Lipoprotein-associated α-tocopherol distribution also changed after SG; however, the clinical significance of these changes requires further investigation.