Subclinical hypothyroidism in pregnancy - assessment of offspring thyroid status and mitochondrial robustness to stress.

Subclinical hypothyroidism's clinical implications on pregnancy are controversial. Consequently, thyrotropin (TSH) cutoff-values for pregnancy are continuously a subject for debate. In subclinical hypothyroidism, altered levels of thyroid hormones may affect mitochondrial function.Objectives were i) to analyze thyroid hormone levels in offspring of women with and without subclinical hypothyroidism ii) to analyze mitochondrial "robustness" in terms of MTG/TMRM ratio in pregnant women and their offspring in relation to thyroid function and iii) to perform differentiate analyses on different TSH thresholds to determine the importance of cutoff-values to results.Pregnant women were included by blood collections prior to a planned cesarean section, and cord samples were collected after delivery. Thyroid status (analyzed by Siemens Healthcare Diagnostics by an electrochemical luminescent immunoassay based on LOCI-technology) grouped the women and their offspring in euthyroid or subclinical hypothyroid, with groups established from previous recommended third-trimester cutoff-value (TSH > 3.0 mIU/L) and the recently recommended cutoff-value in Denmark (TSH > 3.7 mIU/L). Flow cytometric measurements of mitochondrial function in mononuclear blood cells with the fluorophores TetraMethylRhodamine Methyl Ester (TMRM) and Mitotracker Green (MTG) were used to evaluate mitochondrial robustness as the MTG/TMRM ratio.No significant differences in mitochondrial robustness between euthyroid and subclinical hypothyroid cohorts were observed, irrespective of TSH-cutoff applied. Maternal and cord MTG/TMRM ratios were positively correlated. Cord-TSH was elevated in subclinical hypothyroid offspring, independent of TSH cutoff applied. Cord-TSH was associated with maternal TSH-level, maternal smoking and cord arterial-pH.

Expressions of mitochondria-related genes in pregnant women with subclinical hypothyroidism, and expressions of miRNAs in maternal and cord blood.

BACKGROUND: Subclinical hypothyroidism in pregnancy and definition by upper thyrotropin (TSH) cutoff are controversial. As mitochondria are influenced by thyroid hormones, the purpose in this study was to measure expression of mitochondria-related genes in euthyroid and subclinical hypothyroid pregnant women to obtain more knowledge of potential metabolic consequences of maternal subclinical hypothyroidism. In addition, we wished to test if applied TSH-cutoff significantly changed our results of expressed gene-levels. Moreover, we aimed to identify potential microRNA-biomarkers for subclinical hypothyroidism - markers that could be traced to offspring as well. METHODS: From a cohort of at-term pregnant women undergoing planned cesarean section, 77 women had expression levels of the mitochondria-related genes Peroxisome Proliferator-activated Receptor-γ coactivator-1ß (PGC-1ß), mitochondrial Transcription Factor A (TFAM), Superoxide Dismutase 2 (SOD2) and Nuclear Respiratory Factor 2 (NRF-2) determined by qPCR from blood sampled in prior to delivery. Two TSH-cutoff levels defining subclinical hypothyroidism (> 3.0 and > 3.7 mIU/L) were applied for the procession of results, generating two data analyses of the same cohort. In 22 pairwise maternal-cord samples (subclinical hypothyroid/euthyroid-rate 0.5, TSH-cutoff > 3.0 mIU/L), microRNA-expressions (miRNA) were analyzed. RESULTS: All gene expressions were lower in the subclinical hypothyroid group regardless of applied TSH-cutoff, but insignificant except for PGC-1ß at TSH cutoff > 3.0 mIU/L. Two miRNAs (hsa-let-7d-3p and hsa-miR-345-5p) were upregulated in blood from women and offspring (cord blood) with subclinical hypothyroidism. CONCLUSIONS: A trend towards decreased mitochondrial gene expressions in subclinical hypothyroidism were demonstrated. The miRNAs hsa-let-7d-3p and hsa-miR-345-5p might be potential markers of maternal subclinical hypothyroidism. However, larger studies are needed to verify the findings.

Mitochondrial energetics and contents evaluated by flow cytometry in human maternal and umbilical cord blood.

Background: Mitochondrial dysfunction may relate to metabolic disorders. The relation between maternal and fetal mitochondrial function needs attention due to heritage.Objectives: To evaluate the use of the staining methods TetraMethylRhodamine Methyl Ester (TMRM) and Mitotracker Green (MTG) for flow cytometric measurements of umbilical cord blood mitochondrial function. Methods: 53 euthyroid at-term pregnant women and their offspring were included by blood collections. The offspring had blood drawn from the clamped umbilical cord. Flow cytometry with MTG, TMRM and Propidium Iodide were performed the following day. A cell count (antibody coating and flow cytometry) was performed for 9 maternal and cord samples. As a quality control, blood of 32 healthy donors was evaluated by flow cytometric analyzes same day as sampling and the following day to test stability of the measurements.Results: Cord mitochondrial measurements were lower than maternal. Maternal and cord mitochondrial function were positively correlated, especially reflected by MTG fluorescence-intensity (FI). Samples stored presented with very changed fluorescence patterns. However, the fluorescence intensity ratios MTG/TMRM of stained white blood cells were related within same day measurements, depicting an extensive and common bioenergetic cellular change.Conclusion: Cord blood flow cytometry by MTG- and TMRM- staining is possible with fluorescence intensity positively correlated to maternal fluorescence intensity. Storage of blood triggers mitochondrial dynamics. The methods are applicable with certain reservations, and they benefit from their non-invasive character compared to mitochondrial evaluation by muscle-biopsies.

Reduced Gene Expression of Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α in Whole Blood in Euthyroid Patients One Year After Hemithyroidectomy for Benign Euthyroid Goiter.

We have previously reported decreased thyroid function within the laboratory reference range and changes in mitochondrial function after hemithyroidectomy. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and coactivator-1ß (PGC-1ß) are key regulators of mitochondrial biogenesis and function. The aim was to examine the influence of hemithyroidectomy on the longitudinal change in mRNA expression of these genes. In addition, we measured longitudinal changes in mRNA expressions of the mitochoncrial-related genes nuclear factor erythroid-derived 2-like 2 (NFE2L2), mitochondrial transcription factor A (TFAM), and sodium dismutase 2 (SOD2). Twenty-eight patients were examined before and 1, 3, 6, and 12 months after hemithyroidectomy for benign euthyroid goiter. Thyroid stimulating hormone (TSH) and thyroid hormones were measured, and whole blood gene expression of PGC-1α, PGC-1ß, NFE2L2, TFAM, and SOD2 was examined by reverse transcription quantitative Polymerase Chain Reaction. We used mixed effect regression models to investigate changes in gene expression with time. Averaged over all follow-up visits, TSH increased (p=0.001), tT3 declined (p=0.01), and fT4/tT3 ratio increased (p=0.03) over one-year follow-up, but fT4 remained unchanged. Averaged over all follow-up visits, whole blood PGC-1α levels (p<0.001) and SOD2 (p=0.009) levels declined, but PGC-1ß, TFAM, and NFE2L2 did not change over one-year follow-up. The study demonstrates significant downregulation of whole blood PGC-1α and SOD2 gene expressions in hemithyroidectomized patients with a concomitant increase in TSH concentration within the reference range. Thus, hemithyroidectomized patients may likely have impaired mitochondrial function.

Weight Gain and Serum TSH Increase within the Reference Range after Hemithyroidectomy Indicate Lowered Thyroid Function.

Background. Weight gain is frequently reported after hemithyroidectomy but the significance is recently discussed. Therefore, the aim of the study was to examine changes in body weight of hemithyroidectomized patients and to evaluate if TSH increase within the reference range could be related to weight gain. Methods. In a controlled follow-up study, two years after hemithyroidectomy for benign euthyroid goiter, postoperative TSH and body weight of 28 patients were compared to preoperative values and further compared to the results in 47 matched control persons, after a comparable follow-up period. Results. Two years after hemithyroidectomy, median serum TSH was increased over preoperative levels (1.23 versus 2.08 mIU/L, P < 0.01) and patients had gained weight (75.0 versus 77.3 kg, P = 0.02). Matched healthy controls had unchanged median serum TSH (1.70 versus 1.60 mIU/L, P = 0.13) and weight (69.3 versus 69.3 kg, P = 0.71). Patients on thyroxin treatment did not gain weight. TSH increase was significantly correlated with weight gain (r = 0.43, P < 0.01). Conclusion. Two years after hemithyroidectomy for benign euthyroid goiter, thyroid function is lowered within the laboratory reference range. Weight gain of patients who are biochemically euthyroid after hemithyroidectomy may be a clinical manifestation of a permanently decreased metabolic rate.

Persistent cellular metabolic changes after hemithyroidectomy for benign euthyroid goiter.

BACKGROUND: The significance of perturbations of thyroid-stimulating hormone (TSH) and thyroid hormones within the laboratory reference ranges after hemithyroidectomy is unknown. Our aim was to examine changes in TSH and thyroid hormones after hemithyroidectomy for benign euthyroid goiter, focusing on tissue response by examining the mitochondrial membrane potential (MMP) of peripheral blood mononuclear cells (PBMCs) and basal oxygen consumption (V˙O2). MATERIALS AND METHODS: In a prospective study on 28 patients and controls, we examined serum TSH and thyroid hormones before hemithyroidectomy and 1, 3, 6 and 12 months after hemithyroidectomy for benign euthyroid goiter. In the hemithyroidectomy group, flow cytometry was used to measure the MMP of tetramethylrhodamine methyl ester (TMRM)- and MitoTracker Green (MTG)-stained PBMCs, and V˙O2 was measured by an Oxycon Pro apparatus. RESULTS: One year after hemithyroidectomy, TSH had increased from a median of 0.97 mIU/l (interquartile range, IQR: 0.69-1.50 mIU/l) to 2.10 mIU/l (IQR: 1.90-3.00 mIU/l; p < 0.001); free thyroxine (fT4) had decreased from a median of 16.0 pmol/l (IQR: 14.9-17.0 pmol/l) to 14.8 pmol/l (IQR: 14.1-16.4 pmol/l; p = 0.009), whereas total triiodothyronine variations did not differ from those in controls. Concomitantly, the MMP of TMRM- and MTG-stained PBMCs was increased by 58% (p < 0.001) and 22% (p = 0.008), respectively. V˙O2 was increased by 14% (p = 0.01). CONCLUSION: Hemithyroidectomy for benign euthyroid goiter induced persistently increased TSH and decreased fT4, sustained mitochondrial hyperpolarization and increased V˙O2. Our results demonstrate a decrease after hemithyroidectomy of the metabolic state to which the individual is adapted, with persistent cellular metabolic changes in a hemithyroidectomized patient group which is normally considered clinically and biochemically euthyroid.

Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial.

OBJECTIVE: To compare the effects of oral ferrous bisglycinate 25 mg iron/day vs. ferrous sulfate 50 mg iron/day in the prevention of iron deficiency (ID) and iron deficiency anemia (IDA) in pregnant women. DESIGN: Randomized, double-blind, intention-to-treat study. SETTING: Antenatal care clinic. SAMPLE: 80 healthy ethnic Danish pregnant women. METHODS: Women were allocated to ferrous bisglycinate 25 mg elemental iron (Aminojern®) (n=40) or ferrous sulfate 50 mg elemental iron (n=40) from 15 to 19 weeks of gestation to delivery. Hematological status (hemoglobin, red blood cell indices) and iron status (plasma iron, plasma transferrin, plasma transferrin saturation, plasma ferritin) were measured at 15-19 weeks (baseline), 27-28 weeks and 36-37 weeks of gestation. MAIN OUTCOME MEASURES: Occurrence of ID (ferritin <15 µg/L) and IDA (ferritin <12 µg/L and hemoglobin <110 g/L). RESULTS: At inclusion, there were no significant differences between the bisglycinate and sulfate group concerning hematological status and iron status. The frequencies of ID and IDA were low and not significantly different in the two iron groups. The frequency of gastrointestinal complaints was lower in the bisglycinate than in the sulfate group (P=0.001). Newborns weight was slightly higher in the bisglycinate vs. the sulfate group (3601±517 g vs. 3395±426 g, P=0.09). CONCLUSIONS: In the prevention of ID and IDA, ferrous bisglycinate was not inferior to ferrous sulfate. Ferrous bisglycinate in a low dose of 25 mg iron/day appears to be adequate to prevent IDA in more than 95% of Danish women during pregnancy and postpartum.