title: Nitric Oxide as a Marker for Levo-Thyroxine Therapy in Subclinical Hypothyroid Patients.
abstract: Subclinical hypothyroidism (SH) is characterized by a mildly elevated concentration of thyroid stimulating hormone (TSH) despite free thyroxine (FT4) and triiodothyronine (FT3) levels within the reference range. Numerous studies revealed SH to be an independent risk factor for cardiovascular disease (CVD), including atherosclerosis, congestive heart failure, coronary heart disease, ischemic heart disease and the associated mortality. The relationship between SH and CVD is well documented, but the molecular mechanism underlying this correlation remain unknown. Endothelial dysfunction has been recognized as an initial step leading to CVD in patients with SH. Changes in lipid profile, inflammation and/or oxidative stress contribute to the endothelial dysfunction in SH. Moreover, the progression of SH is characterized by significantly decreased nitrite and nitrate levels. Recent animal and clinical studies discussed in this review suggest that nitric oxide (NO) levels could be a reliable biomarker for cardiovascular risk in SH. Understanding the regulation of NO production by thyroid hormone may provide novel and useful knowledge regarding how endothelial dysfunction in SH is linked with CVD and help us to uncover new treatments for SH. We suggest that serum NO level may be an indicator for the introduction and dosage of levothyroxine (LT4) replacement therapy in SH patients. Future studies should focus on understanding the molecular mechanisms underlying the effects of NO in physiological as well as in pathophysiological conditions such as hypothyroidism and their clinical relevance.
authors: Milan
authors: M
authors: Obradovic
authors: Zoran
authors: Z
authors: Gluvic
authors: Emina
authors: E
authors: Sudar-Milovanovic
authors: Anastasija
authors: A
authors: Panic
authors: Jovana
authors: J
authors: Trebaljevac
authors: Vladan
authors: V
authors: Bajic
authors: Milos
authors: M
authors: Zarkovic
authors: Institute of Nuclear Sciences Vinca, University of Belgrade Laboratory of Radiobiology and Molecular Genetics P.O. Box 522, 11000 Belgrade, Serbia. isenovic@yahoo.com.
authors: Esma R
authors: ER
authors: Isenovic
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000209:etiology / Q000378:metabolism; D006801:Humans; D007037:Hypothyroidism / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D012307:Risk Factors; D013972:Thyrotropin / Q000378:metabolism; D013974:Thyroxine / Q000494:pharmacology* / Q000627:therapeutic use*; D014284:Triiodothyronine / Q000378:metabolism
chemical_list: D015415:Biomarkers; D014284:Triiodothyronine; D009569:Nitric Oxide; D013972:Thyrotropin; D013974:Thyroxine