Serum lipoproteins and apolipoprotein E in infants with congenital hypothyroidism

Aortic Intima-Media Thickness in Newborns with Congenital Hypothyroidism

BACKGROUND/AIMS

Congenital hypothyroidism (CH) in neonates is associated with lipid alterations that might be a risk factor for early cardiovascular disease in adult life. The aim of this study was to investigate the effect of CH on lipid metabolism and aortic intima media thickness (aIMT) as a unique finding of the increased risk of atherogenic risk in neonatal age.

METHODS

The study group consisted of 15 newborns with CH who were identified by neonatal mass screening (patient group), and 25 healthy newborns (control group). Serum lipid profiles and aIMT obtained from abdominal aorta were measured in all subjects.

RESULTS

The mean aIMT were higher in the patient group (0.46 ± 0.062 mm) compared with the control group (0.34 ± 0.035 mm; p = 0.006). The weight-adjusted aIMT of patients (0.13 ± 0.017 mm/kg) was also significantly greater than that of the controls (0.10 ± 0.019 mm/kg; p < 0.001). Total serum cholesterol levels were significantly higher in patients than those in healthy controls (130.80 ± 44.46 vs. 99.96 ± 18.87 mg/dl). The other lipid levels including triglyceride, low-density lipoprotein (LDL), high-density lipoprotein cholesterol and LDL cholesterol levels of the patients were slightly higher than those of the controls, without statistical significance.

CONCLUSION

Neonates with CH have significantly higher aIMT with lipid alterations. Hypothyroidism might increase the risk of early atherosclerosis even in the neonatal period.

Changes of red blood cell rheology in newborns with congenital hypothyroidism during treatment

AIM

We aimed to evaluate the deformability characteristics of RBC and the affecting factors in newborns diagnosed with congenital hypothyroidism (CH) and to compare the outcomes after the L-thyroxin treatment.

PATIENTS AND METHODS

Enrolled subjects were divided into two subgroups as "patients" and age-matched healthy "controls". First blood samples were taken from all subjects for measuring elongation index (rEI) and osmotic fragility of RBC (OF), hematic and biochemical analytes affecting the RBC deformability in the neonatal age. All parameters were repeated a month after provided euthyroid state following the treatment in patients and age-matched healthy controls.

RESULTS

There was no difference between both groups in terms of complete blood count parameters and serum analytes (albumin, bilirubin and fibrinogen) except expected age-related changes in the first and second readings. Serum lipid/lipoprotein levels of both groups remained unchanged except triglyceride levels during the study period. The rEI of the patients were lower than that of controls in the first and second readings. The rEIs of the patients became increased, reaching (not equal) the levels of their controls during L-thyroxin treatment. Osmotic fragility of the patients was detected as lower than controls in the first and second readings, and became better during L-thyroxin treatment.

CONCLUSION

Our results indicate that some changes may occur on the hematic and biochemical analytes affecting the RBC deformability features. Neonates with CH have the worst rEI initially, but they reached the indices of the healthy infants thanks to L-thyroxin treatment. Also, their OF features have been improved by L-thyroxin.

The effects of hormones of the hypothalamo-hypophyseal-adrenal, renin-angiotensin, and thyroid hormone systems on the formation of dyscirculatory encephalopathy

Measurements were made of plasma levels of free (f) thyroxine (fT4), triiodothyronine (fT3), thyrotropic hormone (TSH), adrenocorticotrophic hormone (ACTH), aldosterone, and renin in patients with dyscirculatory encephalopathy (DE). Their influences on the development of chronic circulatory insufficiency were assessed. A total of 39 patients were studied (aged 45-73 years) with DE stages I and II, without acute or chronic (in the exacerbation phase) somatic illness. These observations showed that diffuse lesions of brain tissues of different severities were accompanied by the following changes in thyroid homeostasis: 1) significant combined increases in TSH without alteration to the "fT3-TSH" negative feedback regulatory mechanism in patients with stage I DE; 2) significant combined decreases in TSH levels with marked suppression of the conversion of thyroxine into triiodothyronine and an interaction with impairments in the "fT3-hypophysis" system in patients with stage II DE. In addition, there were changes (increases) in cortisol levels with simultaneous decreases in renin levels in patients with stage II DE as compared with patients with stage I DE. Correlation analysis demonstrated the absence of any relationship between the age of the patients, the state of hormonal homeostasis, and the extent of vascular stenosis. These results suggest a role for hormones of the hypothalamo-hypophyseal-adrenal, thyroid, and renin-angiotensin systems in the mechanism by which DE develops as well as the possibility of using tests for these hormones as additional criteria for assessing the severity of diffuse brain lesions.