Muscle uncoupling protein 3 expression is unchanged by chronic ephedrine/caffeine treatment: results of a double blind, randomised clinical trial in morbidly obese females

PLoS One. 2014 Jun 6;9(6):e98244. doi: 10.1371/journal.pone.0098244. eCollection 2014.

Abstract

Ephedrine/caffeine combination (EC) has been shown to induce a small-to-moderate weight loss in obese patients. Several mechanisms have been proposed, among which an increased thermogenic capacity of skeletal muscle consequent to the EC-induced up-regulation of uncoupling protein 3 (UCP3) gene expression. We did a parallel group double-blind, placebo-controlled, 4-week trial to investigate this hypothesis. Thirteen morbidly obese women (25-52 years of age, body-mass index 48.0±4.0 kg/m2, range 41.1-57.6) were randomly assigned to EC (200/20 mg, n = 6) or to placebo (n = 7) administered three times a day orally, before undergoing bariatric surgery. All individuals had an energy-deficit diet equal to about 70% of resting metabolic rate (RMR) diet (mean 5769±1105 kJ/day). The RMR analysed by intention to treat and the UCP3 (long and short isoform) mRNA levels in rectus abdominis were the primary outcomes. Body weight, plasma levels of adrenaline, noradrenaline, triglycerides, free fatty acids, glycerol, TSH, fT4, and fT3 were assessed, as well as fasting glucose, insulin and HOMA index, at baseline and at the end of treatments. Body weight loss was evident in both groups when compared to baseline values (overall -5.2±3.2%, p<0.0001) without significant differences between the treated groups. EC treatment increased the RMR (+9.2±6.8%, p = 0.020), differently from placebo which was linked to a reduction of RMR (-7.6±6.5%, p = 0.029). No significant differences were seen in other metabolic parameters. Notably, no changes of either UCP3 short or UCP3 long isoform mRNA levels were evident between EC and placebo group. Our study provides evidence that 4-week EC administration resulted in a pronounced thermogenic effect not related to muscle UCP3 gene expression and weight loss in morbidly obese females under controlled conditions.

Trial registration: ClinicalTrials.gov NCT02048215.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adult
  • Basal Metabolism*
  • Body Weight
  • Caffeine / administration & dosage
  • Caffeine / adverse effects
  • Caffeine / pharmacology*
  • Caffeine / therapeutic use
  • Ephedrine / administration & dosage
  • Ephedrine / adverse effects
  • Ephedrine / pharmacology*
  • Ephedrine / therapeutic use
  • Epinephrine / blood
  • Fatty Acids / blood
  • Female
  • Glycerol / blood
  • Humans
  • Ion Channels / genetics
  • Ion Channels / metabolism*
  • Middle Aged
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Obesity, Morbid / drug therapy
  • Obesity, Morbid / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Thermogenesis
  • Thyrotropin / blood
  • Triglycerides / blood
  • Uncoupling Protein 3

Substances

  • Fatty Acids
  • Ion Channels
  • Mitochondrial Proteins
  • RNA, Messenger
  • Triglycerides
  • UCP3 protein, human
  • Uncoupling Protein 3
  • Caffeine
  • Thyrotropin
  • Ephedrine
  • Glycerol
  • Epinephrine

Associated data

  • ClinicalTrials.gov/NCT02048215

Grants and funding

The authors have no support or funding to report.