Palmitoyl-carnitine production by blood cells associates with the concentration of circulating acyl-carnitines in healthy overweight women

Maria Chondronikola, Rabia Asghar, Xiaojun Zhang, Edgar L. Dillon, William J. Durham, Zhanpin Wu, Craig Porter, Maria Camacho-Hughes, Yingxin Zhao, Allan R. Brasier, Elena Volpi, Melinda Sheffield-Moore, Nicola Abate, Labros Sidossis, Demidmaa Tuvdendorj

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Background Circulating acyl-carnitines (acyl-CNTs) are associated with insulin resistance (IR) and type 2 diabetes (T2D) in both rodents and humans. However, the mechanisms whereby circulating acyl-CNTs are increased in these conditions and their role in whole-body metabolism remains unknown. The purpose of this study was to determine if, in humans, blood cells contribute in production of circulating acyl-CNTs and associate with whole-body fat metabolism. Methods and results Eight non-diabetic healthy women (age: 47 ± 19 y; BMI: 26 ± 1 kg·m−2) underwent stable isotope tracer infusion and hyperinsulinemic-euglycemic clamp study to determine in vivo whole-body fatty acid flux and insulin sensitivity. Blood samples collected at baseline (0 min) and after 3 h of clamp were used to determine the synthesis rate of palmitoyl-carnitine (palmitoyl-CNT) in vitro. The fractional synthesis rate of palmitoyl-CNT was significantly higher during hyperinsulinemia (0.788 ± 0.084 vs. 0.318 ± 0.012%·hr−1, p = 0.001); however, the absolute synthesis rate (ASR) did not differ between the periods (p = 0.809) due to ∼30% decrease in blood palmitoyl-CNT concentration (p = 0.189) during hyperinsulinemia. The ASR of palmitoyl-CNT significantly correlated with the concentration of acyl-CNTs in basal (r = 0.992, p < 0.001) and insulin (r = 0.919, p = 0.001) periods; and the basal ASR significantly correlated with plasma palmitate oxidation (r = 0.764, p = 0.027). Conclusion In women, blood cells contribute to plasma acyl-CNT levels and the acyl-CNT production is linked to plasma palmitate oxidation, a marker of whole-body fat metabolism. Future studies are needed to confirm the role of blood cells in acyl-CNT and lipid metabolism under different physiological (i.e., in response to meal) and pathological (i.e., hyperlipidemia, IR and T2D) conditions.

Original languageEnglish (US)
Pages (from-to)1310-1319
Number of pages10
JournalClinical Nutrition
Volume36
Issue number5
DOIs
StatePublished - Oct 2017
Externally publishedYes

Keywords

  • Acyl-carnitines
  • Blood cells
  • Insulin resistance
  • Plasma palmitate oxidation
  • Stable isotope tracer

ASJC Scopus subject areas

  • Nutrition and Dietetics
  • Critical Care and Intensive Care Medicine

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