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


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.
Kebapcilar
Levent
L
Department of Internal Medicine, Dokuz Eylul University, Izmir, Turkey. leventkebapcilar@yahoo.com
Comlekci
Abdurrahman
A
Tuncel
Pinar
P
Solak
Ahmet
A
Secil
Mustafa
M
Gencel
Omur
O
Sahin
Mustafa
M
Sari
Ismail
I
Yesil
Sena
S
D000328:Adult; D043303:Aryldialkylphosphatase / Q000097:blood*; D001774:Blood Chemical Analysis; D015992:Body Mass Index; D001837:Body Weights and Measures; D002097:C-Reactive Protein / Q000378:metabolism*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013974:Thyroxine; D017539:Tunica Intima / Q000473:pathology*; D014463:Ultrasonography
D002097:C-Reactive Protein; D043303:Aryldialkylphosphatase; D013974:Thyroxine