title: Particle size determines effects of lipoprotein lipase on the catabolism of n-3 triglyceride-rich particles.
abstract: OBJECTIVE
  The catabolic pathways of n-3 triglyceride (TG) rich particles (n-3 TGRP) have not been clearly elucidated. In this study, we investigated the effects of lipoprotein lipase (LPL) on the catabolism of n-3 TGRP compared to n-6 TGRP in vivo and in vitro, and we determined whether particle size affects the biological functions of LPL in n-3 TGRP catabolism.
  
  
  METHODS
  Four types of lipid emulsions, chylomicron (CM)-sized n-3 TG and n-6 TG emulsions, and very low density lipoprotein (VLDL)-sized n-3 TG and n-6 TG emulsions, were labeled with 1,1'-dioctadecy1-3,3,3',3'-tetramethylindo-carbocyanine perchlorate (DiI) and administered via a bolus injection to LPL gene knockout (LPL+/-) mice in vivo and were added to cultured LPL miRNA-transfected 3T3-L1 adipocytes in vitro.
  
  
  RESULTS
  With CM-sized emulsions, a reduction in LPL expression in LPL+/- mice had almost no effect on tissue uptake of n-3 TG emulsions with smaller changes in their initial blood clearance; however, greater effects were observed for VLDL-sized n-3 TG emulsions with respect to tissue uptake with greater changes in their initial blood clearance, compared to n-6 TG emulsions with the same size. In vitro, LPL miRNA transfection had smaller effects on CM-sized and greater effects on VLDL-sized n-3 TG emulsions, with respect to particle uptake, cell TG mass, particle-cell binding and particle lipolysis.
  
  
  CONCLUSIONS
  These results suggested that LPL is more important for catabolism of n-3 TGRP of smaller size; whereas it is essential for catabolism of all sizes of n-6 TGRP.
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China.
authors.forename: Lulu
authors.initials: L
authors.lastname: Xia
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China.
authors.forename: Chaonan
authors.initials: C
authors.lastname: Fan
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Dong
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Wang
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Pediatrics and the Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Deckelbaum
authors.affiliation: Nutrition Research Unit, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 100045 Beijing, China. Electronic address: qikemin@bch.com.cn.
authors.forename: Kemin
authors.initials: K
authors.lastname: Qi
mesh_terms: D016475:3T3 Cells; D000818:Animals; D005217:Fat Emulsions, Intravenous; D005395:Fish Oils / Q000737:chemistry / Q000493:pharmacokinetics; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008079:Lipoproteins, VLDL / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010316:Particle Size; D014280:Triglycerides / Q000737:chemistry* / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: D005217:Fat Emulsions, Intravenous; D005395:Fish Oils; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030106:very low density lipoprotein triglyceride; D008071:Lipoprotein Lipase
keywords: Chylomicron; Lipoprotein lipase; Mice; Triglyceride rich particles; Very low density lipoprotein; n-3 Triglyceride