Effect of levothyroxine replacement therapy on paraoxonase-1 and carotid intima-media thickness in subclinical hypothyroidism.

Abstract

BACKGROUND:

Paraoxonase-1 (PON-1) may play an important role in atherosclerosis. Atherosclerosis is an inflammatory disease and C-reactive protein is a marker for inflammation. The aim of this study was to determine serum PON-1 activity and high-sensitivity C-reactive protein (hs-CRP) levels and assess carotid intima-media thickness, a marker of early atherosclerotic changes, in patients with subclinical hypothyroidism.

MATERIAL/METHODS:

hs-CRP concentrations and PON-1 activity with respect to carotid intima-media thickness were evaluated in 38 subclinical hypothyroidism patients (normolipidemic, mean age: 49.79+/-10.04 years) before and after 3 months of stable euthyroidism and compared with those of 19 euthyroid normolipidemic healthy individuals (mean age: 49.95+/-8.12 years).

RESULTS:

At baseline, the patients with subclinical hypothyroidism had similar levels of PON-1 activity and hs-CRP and a similar lipid profile as the controls; however, the carotid intima-media thickness was greater than in the controls. Levothyroxine treatment had no effect on serum PON-1 activity and hs-CRP level, but it resulted in a significant reduction in carotid intima-media thickness in the subclinical hypothyroidism patients.

CONCLUSIONS:

PON-1 activity and hs-CRP levels did not significantly differ between subclinical hypothyroid patients and controls. Although levothyroxine treatment might have the potential to reverse the progression of atherosclerosis in subclinical hypothyroid patients, PON-1 activity and hs-CRP levels were not affected by this treatment. The reduction in carotid intima-media thickness was independent of the decrease in serum lipid profile or other variables.

• Authors: Levent Kebapcilar, Abdurrahman Comlekci, Pinar Tuncel, Ahmet Solak, Mustafa Secil, Omur Gencel, Mustafa Sahin, Ismail Sari, Sena Yesil
• Journal: Medical science monitor : international medical journal of experimental and clinical research (Med Sci Monit) Vol. 16 Issue 1 Pg. CR41-7 (Jan 2010) ISSN: 1643-3750 [Electronic] United States
• PMID: 20037493 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• C-Reactive Protein
• Aryldialkylphosphatase
• Thyroxine

Topics

• Adult
• Aryldialkylphosphatase (blood)
• Blood Chemical Analysis
• Body Mass Index
• Body Weights and Measures
• C-Reactive Protein (metabolism)
• Carotid Arteries (diagnostic imaging)
• Hormone Replacement Therapy (methods)
• Humans
• Hypothyroidism (blood, drug therapy, enzymology, pathology)
• Middle Aged
• Statistics, Nonparametric
• Thyroxine
• Tunica Intima (pathology)
• Ultrasonography