The influence of oral lipid loads on acylation stimulating protein (ASP) in healthy volunteers

Int J Obes Relat Metab Disord. 1998 Nov;22(11):1096-102. doi: 10.1038/sj.ijo.0800733.

Abstract

Objectives: To examine the hypothesis that a sustained rise in plasma acylation stimulating protein (ASP, C3a desarg) accompanies the elevation in triacylglycerol that follows the ingestion of an oral fat load.

Design: Following an overnight fast, blood samples were obtained from healthy volunteers while fasting and 15 min, 1, 2, 4, 6 and 8 h following ingestion of: (i) a liquid meal, rich in dairy fat (eight subjects) and (ii) a semi-liquid meal, with higher total fat content and rich in polyunsaturated fat (six subjects).

Subjects and methods: Four male and four female volunteers (age range: 22-51 y; body mass index (BMI): 17.9-26.9 kg/m2) received the first meal. Six subjects (age range: 32-60 y; BMI: 18.0-28.4 kg/m2), including three from the first study, received the second meal using the same protocol. ASP and C5a were measured by radioimmunoassay (RIA) and the complement proteins C3, factor B and C5 by radial immunodiffusion or nephelometry. Tumour necrosis factor (TNF)-alpha was measured by enhanced ELISA, and plasma cholesterol and triacylglycerol by an automated enzymatic method. The presence of chylomicrons was assessed in post-prandial plasma samples taken after the second meal.

Results: There was no significant change in mean ASP concentration in either group at any time point, following ingestion of either meal. However, there was a significant positive linear trend in ASP following the second fat challenge (ANOVA; P < 0.05). There was also no change in complement proteins, plasma cholesterol or TNF-alpha. Plasma triacylglycerol rose significantly after the first and second meals (P < 0.05 and P < 0.001 at 2 h post-prandially); the mean maximum rise above the fasting level was 58 +/- 41% and 89 +/- 38% respectively (mean +/- s.d.). Chylomicrons were detected in samples taken from each subject after the second meal. Analysis of individual ASP data showed a sustained rise in one subject after the first meal and two subjects after the second meal. Substantial variation in ASP concentration was observed in samples taken in the first 2 h post-prandially.

Conclusion: There was no significant change in ASP nor other complement proteins for either group of subjects following ingestion of the lipid loads. Individual data showed substantial variation in post-prandial ASP, but multiple plasma sampling did not define the basis for this variation.

MeSH terms

  • Adult
  • Blood Proteins / metabolism*
  • Body Constitution
  • Body Mass Index
  • Complement C3a* / analogs & derivatives*
  • Dietary Fats / administration & dosage
  • Dietary Fats / pharmacology*
  • Fasting
  • Fatty Acids, Unsaturated / pharmacology
  • Female
  • Humans
  • Lipids / blood
  • Male
  • Middle Aged
  • Postprandial Period
  • Reference Values
  • Triglycerides / blood
  • Tumor Necrosis Factor-alpha / analysis

Substances

  • Blood Proteins
  • Dietary Fats
  • Fatty Acids, Unsaturated
  • Lipids
  • Triglycerides
  • Tumor Necrosis Factor-alpha
  • complement C3a, des-Arg-(77)-
  • Complement C3a