Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2008) 15 OC35

SFEBES2008 Oral Communications Thyroid (8 abstracts)

Circulating endothelial progenitor cells are reduced in subclinical and overt hypothyroidism

Abdul Shakoor 1 , Ali Aldibbiat 2 , Lorna Ingoe 1 , Susan Campbell 2 , Latika Sibal 2 , John Isaacs 2 , James Shaw 2 , Philip Home 2 & Jolanta Weaver 2

1Department of Diabetes and Endocrinology, Queen Elizabeth Hospital, Gateshead, UK; 2School of Clinical Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK.

Introduction: Subclinical hypothyroidism (SCH) is recognised as an increased risk for cardiovascular disease (CVD). Low number of circulating endothelial progenitor cells (EPC), defined as mononuclear cells, expressing endothelial (vascular endothelial growth factor receptor, VEGFR-2) and stem cell (CD-34, CD-133) markers is associated with CVD. Our aim was to identify whether reduced EPC number might contribute to increased CV risk in subclinical and overt hypothyroidism (Hy).


Twenty subjects (matched for age, race, and sex) with SCH, healthy controls (HC) and 11 Hy were studied. We measured EPC number by fluorescence activated cell sorter (FACS) of peripheral blood in monocyte and lymphocyte gates, by in vitro cultures, and performed brachial artery flow mediated dilatation (FMD) before and after thyroxine replacement.

Results: Thyroid stimulating hormone (mean±S.D.) was 2.20±0.98, 6.90±2.51 and 46.55±36.22 mU/l in HC, SCH, and Hy respectively. EPCs were significantly reduced in SCH and Hy compared to HC in FACS analysis (within the lymphocyte gate per 5000 events, mean±S.D.); CD133+/VEGFR-2+ (SCH; 5.8±5.0 vs 29.2+/23.7, P<0.001, Hy; 8.6±4.9 vs 29.2±23.7, P<0.001), CD34+/VEGFR-2+ (SCH; 5.7±6.0 vs 26.0±23.6, P<0.001, Hy; 5.0±4.4 vs 26.0±23.6, P<0.001),and after culture (SCH; 45.0±5.2 vs 49.0±2.6, P<0.05, Hy; 42.0±4.3 vs 49.0±2.6, P=0.001).The FMD results were similar for HC and SCH. EPCs count increased significantly in SCH and Hy following thyroxine replacement; by FACS: CD133+/VEGFR-2+(SCH, 20.6±13.6 vs 5.8±5, P<0.001; Hy, 26.9±15.3 vs 8.6±4.9, P<0.02), CD34+/VEGFR-2+ (SCH, 17.9±12.1 vs 5.7±6.0, P<0.001; Hy, 21.3±12.2 vs 5.0±4.4, P<0.02), in culture (SCH, 54.8±13.5 vs 45.0±5.2, P<0.02; Hy, 50.0±7.0 vs 42.0±4.3, P<0.03). There was no correlation between EPC numbers and FMD.


SCH and Hy are associated with reduced EPCs count in comparison to HC even in this small cohort. This finding confirms that SCH carries a CV risk. The number of EPC improved after thyroxine therapy. This confirms our previous findings of beneficial effect of thyroxine on CVD factors in SCH.

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