Involvement of circulating interleukin-6 and its receptor in the development of euthyroid sick syndrome in patients with acute myocardial infarction.
OBJECTIVE
In patients with acute myocardial infarction (AMI), low triiodothyronine (T(3)) levels with normal or subnormal levels of thyrotropin (TSH), the euthyroid sick syndrome (ESS), have been reported, however, the mechanism of altered thyroid hormone metabolism is unknown. Recent reports have shown that interleukin-6 (IL-6) plays a key role in the pathogenesis of AMI and ESS. This preliminary study investigates the relationship between thyroid states and plasma levels of IL-6, the soluble IL-6 receptor (sIL-6R), and the soluble transducing 130kDa glycoprotein (sgp130) in AMI.


METHODS
We measured the concentration of TSH, free T(3) (FT(3)), free thyroxine (FT(4)), IL-6, sIL-6R and sgp130 in plasma from 24 patients with AMI and 20 normal controls.


RESULTS
All 24 AMI patients showed significantly lower concentrations of FT(3) with normal or subnormal levels of TSH, and higher concentrations of IL-6 and sIL-6R than controls. IL-6 level was correlated with creatine phosphokinase (CPK) and FT(3) levels but not with FT(4 )or TSH levels in patients with AMI. The time course of IL-6 and FT(3 )concentration seemed to be closely linked. sIL-6R level was correlated with CPK and sgp130 levels, but not with FT(3), FT(4) or TSH levels. FT(4 )level was correlated with sgp130 level.


CONCLUSIONS
Patients with AMI develop ESS through activation of IL-6 and its receptor system.
Kimura
T
T
Department of General Medicine and Clinical Laboratory Center, Gunma University School of Medicine, Japan.
Kanda
T
T
Kotajima
N
N
Kuwabara
A
A
Fukumura
Y
Y
Kobayashi
I
I
D000368:Aged; D003402:Creatine Kinase / Q000097:blood; D005067:Euthyroid Sick Syndromes / Q000097:blood / Q000209:etiology*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000150:complications*; D019947:Receptors, Interleukin-6 / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D014284:Triiodothyronine; D013972:Thyrotropin; D003402:Creatine Kinase; D013974:Thyroxine