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Biomedical subjects

Toshiki Nagasaki

Publications and source records attributed to Toshiki Nagasaki.

5 recordsLinked to original sources
PubMed2005

Increased levels of serum osteoprotegerin in hypothyroid patients and its normalization with restoration of normal thyroid function.

Hypothyroidism is associated with increased morbidity from cardiovascular disease, and an increase in serum osteoprotegerin (OPG) has recently been reported to be associated with the severity of coronary heart disease and cardiovascular mortality. The present study was designed to examine whether hypothyroidism causes an increase in serum OPG, and to determine whether levothyroxine (L-T4) replacement therapy might suppress serum OPG levels in hypothyroid patients. Fifty-three hypothyroid patients with chronic thyroiditis and age- and sex-matched normal control subjects were examined for the levels of serum OPG and plasma von Willebrand factor (vWF), a vascular injury marker. Thirty-seven of the hypothyroid patients were further monitored for changes in these markers during 1 year in a euthyroid state induced by L-T4 replacement therapy. Baseline OPG was significantly higher in hypothyroid patients than in normal controls (4.51 +/- 0.50 vs 3.72 +/- 0.23 pmol/l (mean +/- S.E.); P = 0.0182). In multivariate analysis, baseline OPG was significantly associated with baseline levels of TSH (r = 0.280, P = 0.0162) and vWF (r = 0.626, P < 0.0001). During one year of L-T4 replacement therapy, hypothyroid patients showed a significant decrease in OPG levels from 4.35 +/- 0.51 to 3.48 +/- 0.26 pmol/l (P = 0.0166), a level comparable to normal controls. The change in serum OPG levels during L-T4 replacement therapy was significantly and independently associated in a negative fashion with baseline vWF (r = -0.503, P = 0.0014). This study suggested that the severity of hypothyroidism and vascular injury might have important independent roles in increasing the serum OPG level in hypothyroid patients. Furthermore, it was demonstrated that a sustained euthyroid state might have the potential to decrease the serum OPG level in hypothyroid patients and that the degree of vascular injury in the hypothyroid state is independently associated with a decrease in serum OPG during a 1-year normalization of thyroid function.

Female↗
PubMed2004

Decrease of arterial stiffness at common carotid artery in hypothyroid patients by normalization of thyroid function.

This study examined the effect of hypothyroidism on arterial stiffening and the effect of levothyroxine (l-T(4)) replacement. The arterial stiffness index beta (stiffness beta) and intima-media thickness (IMT), a parameter of arterial stiffening and thickening, respectively, were determined in common carotid artery (CCA) by ultrasonography in 30 hypothyroid patients before and after 1 year of normalization of thyroid function by l-T(4) replacement. Baseline CCA stiffness beta and IMT was significantly higher in the hypothyroid patients than in age- and sex-matched normal controls [9.46 +/- 0.93 vs. 8.02 +/- 0.91 (mean +/- SE); P < 0.05, 0.635 +/- 0.018 mm vs. 0.541 +/- 0.019 mm; P < 0.005, respectively]. In multivariate analysis, baseline stiffness beta was significantly associated with baseline levels of IMT (r = 0.457, P = 0.0311), FT(4) (r = -0.413, P = 0.0169), and a plasma vascular injury marker, von Willebrand factor (vWF) (r = 0.412, P = 0.0261). During 1 year of euthyroidism, 22 and 29 out of 30 patients showed significant decreases of stiffness beta and IMT to normal respective level, from 9.46 +/- 0.93 to 7.58 +/- 0.34 and from 0.635 +/- 0.018 to 0.552 +/- 0.015 mm, respectively. Change in stiffness beta during l-T(4) therapy correlated significantly in a negative manner with baseline levels of age (r = -0.465, P = 0.011) and IMT (r = -0.406, P = 0.029). Stiffness beta after but not before l-T(4) therapy showed a tendency towards a positive correlation with age. This study suggested that increases of arterial thickening, and plasma vWF, and a reduction in serum FT(4) might have an important role independently in the increased arterial stiffening in hypothyroid patients. Furthermore, it was demonstrated that sustained euthyroidism might have the potential to reverse arterial stiffening in addition to thickening in hypothyroid patients.

Carotid Artery, Common↗
PubMed2004

Change in von Willebrand factor and carotid intima-media thickness in hypothyroid patients with normal thyroid function after levothyroxine replacement therapy.

OBJECTIVE: This study examined whether levothyroxine (L-T4) replacement might affect serum markers of endothelium injury, including von Willebrand factor (vWF), factor VIII activity and thrombomodulin (TM), during normalization of increased intima-media thickness (IMT) in the common carotid artery (CCA) in hypothyroid patients after L-T4 replacement therapy. PATIENTS AND METHODS: Thirty-three hypothyroid patients were examined for vWF, factor VIII, TM and CCA IMT before and after 1 year of normalization of thyroid function by L-T4 replacement. CCA IMT was measured from digitized still images taken during scanning by high-resolution ultrasonography as an indicator of early atherosclerosis. RESULTS: Serum factor VIII and vWF increased significantly during 1 year of normalization of thyroid function (from 122.7+/-9.4 to 151.3+/-18.8% (P<0.05) and from 109.9+/-9.6 to 135.2+/-12.4% (P<0.005) respectively), although these values all fell within the respective normal range. Serum TM, in contrast, did not change appreciably in response to L-T4 treatment, moving from 2.57+/-0.15 to 2.74+/-0.18 ng/ml (P=0.086). During 1 year of a euthyroid state, all patients showed a significant decrease in CCA IMT (P<0.0001). Change in serum vWF, but not in factor VIII or TM, showed a positive correlation with that of CCA IMT during L-T4 replacement therapy. Furthermore, the change in serum vWF was significantly and independently associated with change in CCA IMT (r=0.490, P=0.0038). CONCLUSIONS: The present study demonstrated that the improvement of CCA IMT during L-T4 treatment might have the potential to attenuate an elevation of vWF and to attenuate vascular injury by the cardiovascular effects of thyroid hormone in hypothyroid patients.

Biomarkers↗
PubMed2003

Decrease in carotid intima-media thickness in hypothyroid patients after normalization of thyroid function.

OBJECTIVE: This case-control study was carried out to assess whether levothyroxine (L-T4) replacement might cause regression of the enhanced atherosclerosis seen in hypothyroid patients. PATIENTS AND METHODS: Intima-media thickness (IMT) in the common carotid artery (CCA) was measured from digitalized still images taken during scanning by high-resolution ultrasonography as an indicator of early atherosclerosis. Thirty-five hypothyroid patients were examined for their CCA IMT before and 1 year after normalization of thyroid function by L-T4 replacement. As control, 35 healthy subjects were enrolled from among the participants in a local health-check programme conducted at the Osaka City University Hospital. RESULTS: Basal CCA IMT was significantly higher in hypothyroid patients [0.635 +/- 0.018 (mean +/- SE) mm] than in control subjects (0.559 +/- 0.021 mm, P < 0.005). After 1 year of euthyroidism, 34 out of 35 patients showed a significant decrease of CCA IMT, to 0.552 +/- 0.015 mm (P < 0.0001), a level comparable to normal controls. CCA IMT change was closely associated with basal levels of total cholesterol (r = -0.472, P= 0.0031), low-density lipoprotein (LDL) cholesterol (r = -0.441, P= 0.0076) and the total/HDL cholesterol ratio (r =-0.435, P= 0.0057), but not with any of the other variables measured except for age (r = -0.353, P= 0.0296). CONCLUSIONS: This study demonstrated that L-T4 treatment might have the potential to reverse the progression of atherosclerosis in hypothyroid patients. Furthermore, it suggests that increased levels of LDL cholesterol and the total/HDL cholesterol ratio have an important role in the increased common carotid intima-media thickness in hypothyroid patients.

Carotid Artery Diseases↗