Thyroid function influences serum apolipoprotein B-48 levels in patients with thyroid disease.
OBJECTIVE
Apolipoprotein B-48 (apoB-48) is a major apolipoprotein of intestine-derived chylomicrons (CM) and CM remnants (CMR). Clinically overt hypothyroidism (OH) has been associated with premature and accelerated coronary atherosclerosis. To clarify the clinical significance of apoB-48 measurement in patients with thyroid disease, we investigated the correlations between the serum apoB-48 level and thyroid hormones.


METHODS
From outpatients of Osaka University Hospital, patients with OH, subjects with subclinical hypothyroidism (SH) and subjects with normal thyroid function were collected and analyzed by measuring serum TSH, FT4 and FT3 levels. Serum apoB-48 levels were measured by a chemiluminescence enzyme immunoassay and the correlations with thyroid hormone levels or lipid profiles were assessed. These levels were compared among subjects with OH, SH and healthy controls.


RESULTS
Serum apoB-48 level was correlated with TSH, total cholesterol (TC) and triglycerides (TG), but negatively with FT4 and FT3 level. LDL-C and HDL-C levels were not correlated with serum apoB-48 levels. Serum apoB-48 in patients with OH (7.4 ± 5.9 µg/mL) was significantly higher than in those with hyperthyroidism (5.1 ± 3.5 µg/mL; p<0.01) and normal subjects (4.7 ± 3.7 µg/mL; p<0.01), but decreased after levo-thyroxine replacement. ApoB-48, TG and TSH were significantly higher in SH subjects than normal subjects, suggesting that serum apoB-48 level depends on the thyroid function status, similar to TC, LDL-C and TG.


CONCLUSIONS
Increased serum apoB-48 concentrations and CMR may contribute to the increased risk of atherosclerosis and premature coronary artery disease in the hypothyroid state.
Division of Laboratory for Clinical Investigation, Department of Medical Technology, Osaka University Hospital, Osaka, Japan.
Satomi
S
Mugii
Hiroyuki
H
Hanada
Manabu
M
Okubo
Daisaku
D
Masuda
Keiko
K
Takeoka
Yoh
Y
Hidaka
Tohru
T
Ohama
Akifumi
A
Matsuyama
Yumiko
Y
Nakagawa-Toyama
Makoto
M
Nishida
Masato
M
Ishigami
Issei
I
Komuro
Shizuya
S
Yamashita
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D053283:Apolipoprotein B-48 / Q000097:blood*; D050197:Atherosclerosis / Q000209:etiology; D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D053298:Chylomicron Remnants / Q000097:blood; D003324:Coronary Artery Disease / Q000209:etiology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D007037:Hypothyroidism / Q000097:blood / Q000150:complications / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013959:Thyroid Diseases / Q000097:blood*; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use; D014280:Triglycerides / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
D053283:Apolipoprotein B-48; D008078:Cholesterol, LDL; D053298:Chylomicron Remnants; D013963:Thyroid Hormones; D014280:Triglycerides; D014284:Triiodothyronine; D013972:Thyrotropin; D002784:Cholesterol; D013974:Thyroxine