Obese adults with primary growth hormone resistance (Laron Syndrome) have normal endothelial function

M. Shechter, S. Ginsberg, M. Scheinowitz, M. S. Feinberg, Z. Laron

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: Classic Laron Syndrome (LS) is a recessive disease of insulin-like growth factor I (IGF-I) deficiency and primary growth hormone insensitivity, clinically characterized by dwarfism and marked obesity. The aim of the current study was to investigate the impact of long-term IGF-I deficiency on flow-mediated dilation (FMD) in 11 non-IGF-I-treated LS adults with long-term IGF-I deficiency who on stress echocardiography were found to have reduced cardiac dimensions and output, but normal left ventricular (LV) ejection fraction at rest and LV contractile reserve following stress. Design: Following an overnight fast we assessed percent improvement in endothelium-dependent FMD (%FMD) and endothelium-independent nitroglycerin (%NTG)-mediated vasodilation non-invasively in the brachial artery, using high resolution ultrasound in 11 non-treated adult patients with LS without known coronary artery disease, and compared them to 11 age- and sex-matched healthy controls. All subjects underwent symptom-limited exercise testing (Bruce protocol). Results: LS patients had a significantly higher body mass index (29 ± 6 vs. 25 ± 2 kg/m2, p = 0.04), lower low-density lipoprotein cholesterol (142 ± 28 vs. 176 ± 12 mg/dl, p = 0.03) and a smaller mean brachial artery diameter (4.63 ± 0.72 vs. 5.70 ± 1.06 mm, p = 0.01) compared to controls. However, brachial artery %FMD and %NTG were not significantly different between the LS patients and controls (13.1 ± 6.2% vs. 15.4 ± 5.2%, p = 0.28 and 22.3 ± 6.0% vs. 18.9 ± 6.2%, p = 0.30; respectively). Cardiac performance, assessed by exercise duration time and metabolic equivalents (METs), was significantly greater in control subjects than in LS patients (10.3 ± 2.0 vs. 6.0 ± 1.4 min, p < 0.01 and 10.2 ± 2.0 vs. 7.2 ± 1.4 METs, p < 0.01; respectively). Conclusions: FMD was found to be within normal limits in non-IGF-I-treated adult patients with LS, despite congenital absence of IGF-I and obesity.

Original languageEnglish
Pages (from-to)165-170
Number of pages6
JournalGrowth Hormone and IGF Research
Volume17
Issue number2
DOIs
StatePublished - Apr 2007
Externally publishedYes

Keywords

  • Angina
  • Coronary disease
  • Dwarfism
  • Endothelium
  • IGF-I deficiency
  • Laron syndrome
  • Obesity

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