Sympathetic and haemodynamic responses to lipids in healthy human ageing

John P. Florian, James Anthony Pawelczyk

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Plasma non-esterified fatty acids (NEFAs) activate the sympathetic nervous system and increase vascular resistance and blood pressure (BP); however, the response with ageing is not known. The objectives of this study were to characterize the cardiovascular, neural and endocrine responses to acute elevation of NEFA concentration. Seventeen healthy older volunteers (7 male and 10 female; age, 69 ± 1 years; body mass index, 24 ± 0 kg m -2; values are means ± s.e.m.) received a 4 h intravenous infusion of the lipid emulsion Intralipid ® 20% or placebo (single-blind, randomized, balanced order) on two different days separated by at least 2 weeks. Muscle sympathetic nerve activity (MSNA), heart rate (HR), BP, cardiac output, leptin, insulin, aldosterone, angiotensin II and F 2-isoprostanes were measured. The change in HR (+8.8 ± 0.9 versus +3.0 ± 0.9 beats min-1), systolic BP (+13.9 ± 2.2 versus +6.6 ± 2.4 mmHg) and diastolic BP (+7.4 ± 1.5 versus +1.3 ± 0.8 mmHg) was significantly greater after Intralipid ® versus placebo infusions (P < 0.001). Lipid infusion increased MSNA burst frequency (+6.7 ± 1.6 bursts min-1), total MSNA (+45%; P < 0.001) and concentrations of insulin (+40%), aldosterone (+50%) and F2-isoprostanes (+80%), but not leptin. Hyperlipidaemia caused directionally opposite responses for insulin (increased) and calf vascular resistance (decreased) in men, whereas insulin and calf vascular resistance responses were severely blunted and non-existent, respectively, in women. We conclude that direct vascular mechanisms and central sympathetic activation contribute to the NEFA pressor response; though absolute values are higher, the change is not different compared with previous studies in a younger population.

Original languageEnglish (US)
Pages (from-to)486-497
Number of pages12
JournalExperimental Physiology
Volume95
Issue number4
DOIs
StatePublished - Jan 1 2010

Fingerprint

Hemodynamics
Blood Pressure
Lipids
Vascular Resistance
Insulin
Fatty Acids
Leptin
Aldosterone
Muscles
Intravenous Fat Emulsions
Heart Rate
F2-Isoprostanes
Placebos
Isoprostanes
Sympathetic Nervous System
Hyperlipidemias
Intravenous Infusions
Angiotensin II
Cardiac Output
Blood Vessels

All Science Journal Classification (ASJC) codes

  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)

Cite this

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title = "Sympathetic and haemodynamic responses to lipids in healthy human ageing",
abstract = "Plasma non-esterified fatty acids (NEFAs) activate the sympathetic nervous system and increase vascular resistance and blood pressure (BP); however, the response with ageing is not known. The objectives of this study were to characterize the cardiovascular, neural and endocrine responses to acute elevation of NEFA concentration. Seventeen healthy older volunteers (7 male and 10 female; age, 69 ± 1 years; body mass index, 24 ± 0 kg m -2; values are means ± s.e.m.) received a 4 h intravenous infusion of the lipid emulsion Intralipid {\circledR} 20{\%} or placebo (single-blind, randomized, balanced order) on two different days separated by at least 2 weeks. Muscle sympathetic nerve activity (MSNA), heart rate (HR), BP, cardiac output, leptin, insulin, aldosterone, angiotensin II and F 2-isoprostanes were measured. The change in HR (+8.8 ± 0.9 versus +3.0 ± 0.9 beats min-1), systolic BP (+13.9 ± 2.2 versus +6.6 ± 2.4 mmHg) and diastolic BP (+7.4 ± 1.5 versus +1.3 ± 0.8 mmHg) was significantly greater after Intralipid {\circledR} versus placebo infusions (P < 0.001). Lipid infusion increased MSNA burst frequency (+6.7 ± 1.6 bursts min-1), total MSNA (+45{\%}; P < 0.001) and concentrations of insulin (+40{\%}), aldosterone (+50{\%}) and F2-isoprostanes (+80{\%}), but not leptin. Hyperlipidaemia caused directionally opposite responses for insulin (increased) and calf vascular resistance (decreased) in men, whereas insulin and calf vascular resistance responses were severely blunted and non-existent, respectively, in women. We conclude that direct vascular mechanisms and central sympathetic activation contribute to the NEFA pressor response; though absolute values are higher, the change is not different compared with previous studies in a younger population.",
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Sympathetic and haemodynamic responses to lipids in healthy human ageing. / Florian, John P.; Pawelczyk, James Anthony.

In: Experimental Physiology, Vol. 95, No. 4, 01.01.2010, p. 486-497.

Research output: Contribution to journalArticle

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