Correlation between maternal thyroid function tests and endothelin in preeclampsia-eclampsia

Effect of Preeclampsia on Ultrastructure of Thyroid Gland, Hepatic Type 1 Iodothyronine Deiodinase, and Thyroid Hormone Levels in Rats

Background

Although hypothyroidism during pregnancy may develop grave outcomes for both mothers and offspring, management of which is still a challenge due to the insufficient understanding of this disease. The close correlation between hypothyroidism and preeclampsia is well documented, suggesting that preeclampsia is a potential risk factor for the development of maternal hypothyroidism. However, the exact role of preeclampsia in gestational hypothyroidism is still obscure.

Objective

In this study, we explored the possible mechanisms of the effect of preeclampsia on thyroid function of maternal rats.

Methods

Thirty pregnant rats were randomly divided into normal pregnancy control (NOP), preeclampsia (PE), and preeclampsia supplemented with amlodipine besylate (PEAml). NG-Nitro-L-arginine-methyl ester was used to induce preeclamptic symptoms. On gestational day 21, rats were sacrificed, and then, the ultrastructure of the thyroid gland, type 1 iodothyronine deiodinase (Dio1) expression, and serum-free thyroxine (FT₄), free triiodothyronine (FT₃), and thyroid stimulation hormones (TSH) were assessed.

Results

Compared to NOP rats, results of PE rats showed that thyroid follicular cells' ultrastructure was damaged; both hepatic Dio1 mRNA and protein levels were decreased. Interestingly, these changes were ameliorated in PEAml rats. Additionally, FT₄, FT₃, and TSH levels have no significant differences among groups.

Conclusion

These findings indicated that preeclampsia could disrupt synthesis, secretion, and metabolism function of thyroid hormones by damaging thyroid follicular cells and interfering Dio1 expression.

Genetics in endocrinology: genetic variation in deiodinases: a systematic review of potential clinical effects in humans

Iodothyronine deiodinases represent a family of selenoproteins involved in peripheral and local homeostasis of thyroid hormone action. Deiodinases are expressed in multiple organs and thyroid hormone affects numerous biological systems, thus genetic variation in deiodinases may affect multiple clinical endpoints. Interest in clinical effects of genetic variation in deiodinases has clearly increased. We aimed to provide an overview for the role of deiodinase polymorphisms in human physiology and morbidity. In this systematic review, studies evaluating the relationship between deiodinase polymorphisms and clinical parameters in humans were eligible. No restrictions on publication date were imposed. The following databases were searched up to August 2013: Pubmed, EMBASE (OVID-version), Web of Science, COCHRANE Library, CINAHL (EbscoHOST-version), Academic Search Premier (EbscoHOST-version), and ScienceDirect. Deiodinase physiology at molecular and tissue level is described, and finally the role of these polymorphisms in pathophysiological conditions is reviewed. Deiodinase type 1 (D1) polymorphisms particularly show moderate-to-strong relationships with thyroid hormone parameters, IGF1 production, and risk for depression. D2 variants correlate with thyroid hormone levels, insulin resistance, bipolar mood disorder, psychological well-being, mental retardation, hypertension, and risk for osteoarthritis. D3 polymorphisms showed no relationship with inter-individual variation in serum thyroid hormone parameters. One D3 polymorphism was associated with risk for osteoarthritis. Genetic deiodinase profiles only explain a small proportion of inter-individual variations in serum thyroid hormone levels. Evidence suggests a role of genetic deiodinase variants in certain pathophysiological conditions. The value for determination of deiodinase polymorphism in clinical practice needs further investigation.

The effect of the D1-C785T polymorphism in the type 1 iodothyronine deiodinase gene on the circulating thyroid hormone levels in Romanian women with preeclampsia. Association with the degree of severity and pregnancy outcome of preeclampsia

AIM

To investigate the biochemical and genetic thyroid status in women with preeclampsia by the determination of serum FT3 and FT4 levels in association with D1-C785T genotypes.

METHODS

We genotyped using PCR-RFLP methods 50 women with preeclampsia and 50 normotensive pregnant women.

RESULTS

FT3 levels (pg/ml, 2.63 ± 0.56 vs. 2.91 ± 1.41) were low, and FT4 levels (ng/dl, 1.11 ± 0.3 vs. 0.88 ± 0.14) were high in women with preeclampsia compared to normal pregnant women. The association with severe preeclampsia was stronger for the homozygous T/T genotype (OR 6.57, p = 0.029). Women with preeclampsia with the D1-T785 mutated allele had lower FT3 levels (pg/ml, 2.31 ± 0.81 vs. 3.04 ± 0.39, p < 0.001), higher FT4 levels (ng/dl, 1.32 ± 0.87 vs. 0.84 ± 0.24, p = 0.009) than women with preeclampsia with the D1-C/C genotype. Significant decrease in serum FT3 levels in positive women with severe preeclampsia compared to women negative for this genetic variation (pg/ml, 1.59 ± 0.74 vs. 2.77 ± 0.23, p = 0.003) was observed. Women with severe preeclampsia, positive for the mutated T785 allele, delivered at a significantly lower gestational age (31.75 ± 3.69 vs. 38.66 ± 3.21 weeks, p = 0.035) neonates with a lower birth weight (1861.11 ± 869.9 vs. 3500 ± 424.26 g, p = 0.023) compared to women negative for the same allele.

CONCLUSIONS

Thyroid hormone levels and the D1-C785T polymorphism, alone or in combination, correlate with the severity of preeclampsia. The D1-C785T polymorphism influences the outcome of pregnancy in severe preeclampsia.

Correlation between the TSHRc-Asp727Glu polymorphism and plasma thyroid stimulating hormone levels in Romanian preeclamptic women

AIM

To analyze the influence of thyroid stimulating hormone (TSH) levels and/or the Asp727Glu polymorphism on the severity and perinatal outcome of preeclampsia.

METHODS

Forty-nine women with preeclampsia and 58 normal pregnant women were genotyped for the TSHRc-Asp727Glu polymorphism using PCR-RFLP methods. The plasma TSH levels were measured by ELISA method.

RESULTS

Fourteen (77.78%) women of 18 pregnant women with abnormal TSH levels had preeclampsia compared to 35 (39.33%) of 89 pregnant women with normal TSH levels who had preeclampsia (OR 5.4, p = 0.003). The mean TSH levels were 2.13 ± 1.44 μU/ml, 2.47 ± 2.03 μU/ml and 4.27 ± 2.75 μU/ml in women with pregnancy induced hypertension (PIH), mild and severe preeclampsia, respectively. OR for PIH and mild preeclampsia was 1.08 (p = 1) and 9.45 (p = 0.06), respectively, in association with the Asp/Asp genotype. All women with severe preeclampsia had the Asp/Asp genotype. The risk for preeclampsia in association with TSH > 4 μU/ml and Asp/Asp genotype is 20.8 (p < 0.01). Preeclamptic women with TSH levels > 4 μU/ml and the Asp/Asp genotype delivered earlier (weeks, 34.92 ± 4.33 vs. 36.6 ± 3.21, p = 0.3) neonates with lower birth weight (grams, 2361.54 ± 1155.81 vs. 3000 ± 1072.38, p = 0.3) than preeclamptic women with TSH levels  < 4 μU/ml and the Asp/Glu genotype.

CONCLUSIONS

Higher TSH levels and/or the TSHRc-Asp727Glu polymorphism represent risk factors for preeclampsia and could be correlated with the severity of preeclampsia.

The gonadotropins: tissue-specific angiogenic factors?

The gonadotropins, whose members are human chorionic gonadotropin (hCG), lutenizing hormone (LH) and follicle-stimulating hormone (FSH) are a well characterized hormone family known to regulate reproductive functions in both females and males. Recent studies indicate that they can modulate the vascular system of reproductive organs. It was shown that gonadotropins not only influence the expression of vascular endothelial growth factor (VEGF) and both its receptors VEGFR-1 and -2, but also modulate other ubiquitously expressed angiogenic factors like the angiopoietins and their receptor Tie-2, basic fibroblast growth factor or placental-derived growth factor. Some recent data indicates a possible direct action of gonadotropins on endothelial cells. Thus, the gonadotropins act as tissue-specific angiogenic factors providing an optimal vascular supply during the menstrual cycle and early pregnancy in the female reproductive tract as well as in testis. In pathological conditions (e.g. preeclampsia, intrauterine growth restriction, ovarian hyperstimulation or endometriosis), these tightly regulated interactions between the gonadotropins and the ubiquitous angiogenic factors appear to be disturbed. The intent of this short manuscript is to review the current knowledge of the regulatory role of the gonadotropins in vasculo- and angiogenesis. We also review angiogenic actions of thyroid-stimulating hormone (TSH), a glycoprotein closely related to gonadotropins, which display strong gonodal actions.

Maternal erythrocyte malondialdehyde level in preeclampsia prediction: a longitudinal study

We aimed to determine the value of maternal erythrocyte malondialdehyde levels in the prediction of preeclampsia. 110 healthy women were included in this prospective study. Maternal erythrocyte malondialdehyde levels were measured at each trimester of pregnancy (10-14, 20-25 and 30-35 gestational weeks). On follow-up, patients were assigned to two groups as normotensive women and preeclamptic patients. Preeclampsia had developed in eight (8.9%) of the 90 pregnant women who completed the study. Preeclamptic patients were diagnosed between 36 and 39 gestational weeks (36.8 +/- 1.0 weeks). Malondialdehyde levels of preeclamptic patients increased significantly in the third trimester (p < 0.05), while there was no difference between values of malondialdehyde in the first and second trimester. Malondialdehyde levels were significantly higher in the patients who developed preeclampsia than in those who did not in the third trimester (p < 0.05). With the use of the receiver operating characteristics (ROC) 35.98 nmol malondialdehyde/gm hemoglobin was found to be a cut-off value predictive for the development of preeclampsia in the third trimester. However, cut-off values in the first and second trimesters could not be found. The sensitivity, specificity, positive and negative predictive values were 89, 75, 29 and 98%, respectively. Preeclampsia risk was found to increase nearly 24 times in values above 35.98 nmol malondialdehyde/ gm hemoglobin. Our results showed that maternal erythrocyte malondialdehyde could predict patients within a few weeks prior to onset of clinical symptoms of preeclampsia in the third trimester. There is no evidence of enhanced early lipid peroxidation in pregnancies with late onset preeclampsia.

Thyroid hormone alteration in pre-eclamptic women

This study sought a possible relationship between pre-eclampsia and thyroid profile. In a case-control setting, total thyroxine (T4), total tri-iodothyronine (T3), free T4, free T3, thyroxine binding globulin (TBG) and thyrotropin (TSH) levels in 39 pre-eclamptic patients were measured and compared with the levels in 42 healthy controls. We examined possible variations with regard to the severity of pre-eclampsia by dividing cases into mild (n = 17) and severe (n = 22) subgroups. Patients with mild pre-eclampsia showed significantly increased free T4 and TSH levels compared to healthy controls. In severe cases, TSH level was higher, but free T3 and free T4 levels were significantly lower than in controls. Other tests returned non-significant differences between the groups. Our findings suggest that primary hypofunctioning of the thyroid can accompany mild pre-eclampsia and possibly contribute to the pathogenesis. Elevated levels of free thyroid hormones in severe cases, however, may have reflected a preceding thyroid disorder.

Androgen levels of preeclamptic patients in the third trimester of pregnancy and six weeks after delivery

BACKGROUND

The aim of this study was to measure the circulating levels of androgens in the third trimester of pregnancy and six weeks after delivery and to discuss androgen contribution in the pathogenesis of preeclampsia.

METHODS

Twenty-two preeclamptic and 20 normotensive women completed this prospective study. Blood samples were drawn in the third trimester (28-32 gestational weeks) and six weeks after delivery. Serum total testosterone (T), free testosterone (fT) dehydroepiandrosterone sulfate (DHEAS), androstenodione (A), sex hormone binding globulin (SHBG) and estradiol (E2) levels were measured. The statistical analyses of the data were performed by using Wilcoxon Rank test within the groups, Student unpaired t test and Chi-square test between the groups with the SPSS program.

RESULTS

T and fT levels were found to be significantly higher (p<0.05) in preeclamptic women in the third trimester compared to the values of normotensive controls. However, there were significant decreases (p<0.05) in T and fT levels six weeks after delivery, reaching values not significantly different from normotensive subjects (p>0.05). Furthermore, SHBG, DHEAS, A and E2 levels were not significantly different (p>0.05) between the groups in the third trimester or six weeks after delivery.

CONCLUSION

We conclude that higher blood androgen levels measured in preeclamptic patients may be implicated in the pathogenesis of preeclampsia.