Reverse T3 Research Articles

FRI475 The Impact Of Suppression Of Androgen Signaling On Thyroid Hormone Homeostasis In Prostate Cancer Patients

Abstract Disclosure: K. David: None. G. Devos: None. W. Devlies: None. N. Narinx: None. L. Antonio: None. L. Deboel: None. D. Schollaert: None. D.M. Vanderschueren: None. F.A. Claessens: None. S. Joniau: None. B. Decallonne: None. Next to the classical androgen deprivation therapy (ADT) with GnRH-(ant)agonists, androgen receptor signaling inhibitors (ARSIs) such as apalutamide (APA) have become available for the treatment of prostate cancer (PC) patients in the last years. Hypothyroidism was more frequent in APA-treated patients compared to placebo in the SPARTAN trial (NCT01946204) (8.1% vs 2%). We collected serum of PC patients included in a RCT (ARNEO; NCT03080116) before and after 12 weeks of neo-adjuvant ADT (GnRH-antagonist degarelix (DGX) with APA or placebo). We aimed to explore changes in thyroid homeostasis under deep androgen suppression with combined GnRH-antagonist and ARSI. Of the 88 patients ending the trial, 1 was excluded because of history of hypothyroidism for which he received levothyroxine. 43 and 44 patients were included in the DGX+placebo and DGX+APA group, respectively. Mean age was 66.3y. Sex steroid levels measured by LC-MS/MS decreased significantly to castrate range with median testosterone 10.5 ng/dL and estradiol 3.6 ng/L. TSH levels increased in both treatment groups, but more pronounced in the DGX+APA group (DGX+placebo before: 1.18 mIU/L and after: 1.33 mIU/L, p 0.0351 vs. DGX+APA before: 1.07 mIU/L and after: 1.87 mIU/L, p <0.0001; difference between groups after treatment: p <0.0001). Free T4 and total T4 levels decreased in the DGX+APA group, but remained unaltered in the DGX+placebo group (free T4 after: 16.53 vs 13.87 pmol/L, p<0.0001 and total T4 after: 8.77 vs. 7.78 µg/dL, p 0.0055). Total T3 and free T3 increased in the DGX+APA group, and again did not differ after treatment in the DGX+placebo group. (free T3 after: 5.03 vs 5.41 pmol/L, p 0.0066 and total T3 after: 132.30 vs 149.50 ng/dL, p 0.0003). As a result, the total and free T3/T4 ratio increased in the DGX+APA group with 32% and 35%, respectively. Reverse T3 decreased in both treatment arms, but greater in the DGX+APA group (19.55 vs 14.20 ng/dL, p 0.0157). Thyroxine binding globulin (TBG) increased in both treatment arms, with 6.9% and 8.4%, respectively. In conclusion, interference with androgen signaling alters thyroid homeostasis in PC patients, and is most pronounced under deep androgen suppression with combined GnRH-antagonist and ARSI therapy. The increase in T3 and decrease in rT3 may indicate additional effects of ARSI on deiodinase activity. Longer follow-up trials are needed to confirm these findings and assess the clinical implications of these changes in thyroid homeostasis. Presentation: Friday, June 16, 2023

A-032 Comparative Serum Free Thyroxine Measurements between Immunoassays and ID-LC/MS/MS Procedure Based on Equilibrium Dialysis

Abstract Background Serum free thyroxine (FT4) measurement is one of the most important clinical laboratory tests for diagnosis and classification of thyroid disorders. Currently serum FT4 is commonly measured with Immunoassays (IAs) in patient care. However, there are concerns about the accuracy of FT4 IAs. A reference measurement procedure (RMP) for FT4 based on well-defined equilibrium dialysis (ED) of serum has been established for standardization of routine FT4 IAs. As FT4 RMP is not intended for routine clinical application, in the current study, we aim to develop a high-throughput routine FT4 method based on ED-isotope dilution liquid chromatography tandem mass spectrometry (ED-ID-LC/MS/MS). FT4 RMP was used as a reference to evaluate the measurement accuracy of our ED-ID-LC/MS/MS method and an IA method, respectively. Methods FT4 in dialysate was isolated from protein-bound T4 in serum by using a commercially available micro-ED plate after 18-h ED. The 13C6 labeled T4 was added into dialysate as an internal standard. FT4 in dialysate was purified with 96-well C18 SPE plate. FT4 in the dialysate samples was analyzed by using LC/MS/MS. The T4 certified primary reference material (IRMM-468) was used for assay calibration. FT4 IA measurement was conducted in clinical analyzers (Roche e411). A set of 40 single donor sera, covering a FT4 concentration range of 11.2–32.1 pmol/L were measured by IA and our ED-ID-LC/MS/MS, respectively. Deming regression analysis was performed to compare the results obtained by these two methods with the reference values assigned by FT4 RMP. Results The described high-throughput method based on ED-ID-LC/MS/MS could simultaneously quantified T4, T3, reverse triiodothyronine (rT3) in the dialysate within 4.5 min. The linear range of the routine FT4 assay covered 1–100 pg/mL. The assay sensitivity allowed detection of 0.3 pg/mL FT4 in serum, which is sufficient for FT4 measurement in clinically relevant ranges including hypothyroid patient samples. The throughput of the ED-ID-LC/MS/MS method could be further improved by application of automated liquid handling system. Deming regression analysis showed good agreement between RMP and the routine ED-ID-LC/MS/MS method with a slope close to 1 (P > 0.05) and an intercept close to 0 (P > 0.05), indicating that the results generated from the platform of high-throughput ED-ID-LC/MS/MS could be tracible to FT4 RMP. However, proportional bias (P < 0.05) with slope of 0.74 and constant bias (P < 0.05) with intercept of 2.6 was observed between RMP and IA tested, indicating calibration bias should be addressed to standardize IA. Conclusion In summary, the accuracy, sensitivity, and throughput of ED-ID-LC/MS/MS method are appropriate for FT4 measurements in clinical laboratories and in large epidemiologic studies to establish accurate reference intervals for FT4. Population data generated by FT4 ED-ID-LC/MS/MS method will support the use of standardized FT4 measurements.

Diagnosis ofResistance to Thyroid Hormone due toa Rare Mutation inthe Thyroid Hormone Receptor Beta Gene ina Patient Previously Presumed to Have Graves' Disease.

Clinicians may confuse an impaired sensitivity to thyroid hormone with hyperthyroidism and offer an inappropriate treatment. We report a diagnosis of resistance to thyroid hormone (RTH) caused by a rare mutation in the thyroid hormone receptor beta gene in a patient previously presumed to have Graves' disease. We have found only one published case of a novel point mutation, c.749T>C (p.Ile250Thr variant) associated with 50% reduction in thyroid hormone receptor binding affinity for triiodothyronine in the I250T mutant; it was found in this patient. A 66-year-old male veteran, with a history of non-ischemic cardiomyopathy and arrhythmias, was referred by a cardiologist with concerns for a possible thyrotropin (TSH) adenoma on account of elevated TSH and free thyroxine (FT4) levels. Pituitary imaging was negative. He was previously treated with radioiodine for presumptive Graves' disease in the civilian sector. Examination revealed a goiter with no nodules. Repeat TSH and FT4 levels were elevated and also free triiodothyronine (FT3) and reverse triiodothyronine. These findings and other test results were consistent with RTH, which was confirmed by genetic testing. Mutation analysis showed the patient to be heterozygous for the p.Ile250Thr variant. He later developed hypothyroidism. Resistance to thyroid hormone can be misdiagnosed as hyperthyroidism with consequent inappropriate treatment. Treatment is not needed in most RTH-beta patients. Thyroid ablation should generally be avoided. Clinicians must be cautious whenever they encounter concurrent elevation of TSH, FT4, and FT3. This RTH-beta patient has a rare I250T mutant of the thyroid hormone receptor beta gene, the second reported case in the literature.

Clinical and Biochemical Characteristics of Untreated Adult Patients With Resistance to Thyroid Hormone Alpha.

Thyroid hormone resistance due to pathogenic variants in thyroid hormone receptor alpha (THRA) is rare and descriptions of patients are sparse. The disorder is probably underdiagnosed as patients may have normal thyroid function tests. Treatment with thyroxine in childhood improves clinical symptoms. However, it is not clear if treatment has beneficial effects if started in adulthood. We investigated 4 previously untreated Caucasian adult first-degree-related patients with the THRA c.788C > T, p.(Ala263Val) variant identified by a gene panel for intellectual disability in the index patient. Clinical data and previous investigations were obtained from medical reports. During childhood and adolescence, short stature, short limbs, metacarpals, and phalanges, and delayed bone age maturation were observed. Delayed motor and language development and decreased intellectual and learning abilities were described. Abdominal adiposity, round face, and increased head circumference were common features. All individuals complained of tiredness, constipation, and low mood. While thyrotropin (TSH) and free thyroxine (FT4) were within the reference range, free triiodothyronine (FT3) was high. FT4/FT3 ratio and reverse T3 were low. Other main features were low hemoglobin and high LDL/HDL ratio. Investigation of 4 first-degree-related adult patients with untreated resistance to thyroid hormone alpha (RTHα) revealed more pronounced phenotype features and hypothyroid symptoms than previously described in patients treated with levothyroxine from childhood or adolescence. The delay in diagnosis is probably due to normal thyroid function tests. We suggest that THRA analysis should be performed in patients with specific clinical features, as treatment in early childhood may improve outcomes.

Endocrinology for the hepatologist.

Endocrinology for the hepatologist.

Changes in thyroid function parameters 3 months after allogeneic and autologous hematopoietic stem cell transplantation in children.

Thyroid dysfunction (hypo- and hyperthyroidism) has been reported as a late effect after hematopoietic stem cell transplantation (HSCT) in children. Short-term effects of HSCT on thyroid function parameters are, however, unclear. We prospectively evaluated thyroid function parameters before and 3 months after HSCT in all children (<21 years) who underwent HSCT during a 2-year period in the Princess Máxima Center, the Netherlands. Among 72 children, none had thyroidal hypothyroidism or hyperthyroidism 3 months after HSCT. Changes in thyroid function parameters (either aberrant thyroid-stimulating hormone [TSH] or free thyroxine [FT4] concentrations) were found in 16% before and in 10% 3 months after HSCT. Reverse triiodothyronine (rT3) was found elevated in 9.3% before and in 37% 3 months after HSCT, which could be related to poor physical condition. An individual decline in FT4 concentration of ≥20% was found in 10.5% (6/57) 3 months after HSCT. In conclusion, thyroidal hypo- and hyperthyroidism are very rare 3 months after HSCT. These results indicate that surveillance for hypo- and hyperthyroidism may start later in time. The changes in thyroid function parameters found 3 months after HSCT might reflect euthyroid sick syndrome.

Mercury Bioaccumulation and Cortisol Interact to Influence Endocrine and Immune Biomarkers in a Free-Ranging Marine Mammal

Mercury bioaccumulation from deep-ocean prey and the extreme life history strategies of adult female northern elephant seals (Mirounga angustirostris) provide a unique system to assess the interactive effects of mercury and stress on animal health by quantifying blood biomarkers in relation to mercury (skeletal muscle and blood mercury) and cortisol concentrations. The thyroid hormone thyroxine (tT4) and the antibody immunoglobulin E (IgE) were associated with mercury and cortisol concentrations interactively, where the magnitude and direction of the association of each biomarker with mercury or cortisol changed depending on the concentration of the other factor. For example, when cortisol concentrations were lowest, tT4 was positively related to muscle mercury, whereas tT4 had a negative relationship with muscle mercury in seals that had the highest cortisol concentrations. Additionally, we observed that two thyroid hormones, triiodothyronine (tT3) and reverse triiodothyronine (rT3), were negatively (tT3) and positively (rT3) associated with mercury concentrations and cortisol in an additive manner. As an example, tT3 concentrations in late breeding seals at the median cortisol concentration decreased by 14% across the range of observed muscle mercury concentrations. We also observed that immunoglobulin M (IgM), the pro-inflammatory cytokine IL-6 (IL-6), and a reproductive hormone, estradiol, were negatively related to muscle mercury concentrations but were not related to cortisol. Specifically, estradiol concentrations in late molting seals decreased by 50% across the range of muscle mercury concentrations. These results indicate important physiological effects of mercury on free-ranging apex marine predators and interactions between mercury bioaccumulation and extrinsic stressors. Deleterious effects on animals' abilities to maintain homeostasis (thyroid hormones), fight off pathogens and disease (innate and adaptive immune system), and successfully reproduce (endocrine system) can have significant individual- and population-level consequences.

Non-thyroidal illness syndrome and its relationship with mortality risk in critically ill children.

Non-thyroidal illness syndrome (NTIS) is considered to be associated with adverse outcomes in critically ill children.The hypothesis that thyroid hormones and inflammatory markers are associated with increased prediction of mortality risk scores is tested in this paper. A prospective observational study was set up in a pediatric intensive care unit (PICU). One hundred and three patients were included. NTIS was defined as a low free triiodothyronine (FT3) value for the patient's age. Thyroid hormones levels and inflammatory markers were determined at admission: FT3, FT4 (free thyroxine), TSH (thyroid-stimulating hormone), rT3 (reverse triiodothyronine), CRP (C-reactive protein) and PCT (Procalcitonin). They were compared between children with a pediatric risk of mortality score PRISM-III >75th percentile (group A, n= 25) and the rest (group B, n = 78). A FT4 value lower than 16.6 pmol/L showed an area under the curve (AUC) of 0.655 (0.56-0.78, p = 0.02), with 76% sensitivity and 61.5% specificity to detect a high risk of mortality. A multiple regression analysis revealed that a FT4 lower than 16.6 pmol/L [OR: 4.92 (1.60-18.19), p = 0.009] and having NTIS [OR: 6.04 (1.45-27.93), p = 0.016] could predict a high risk of mortality. In unselected critically ill children, FT4 and FT3 values at admission could be used as a good predictor of a high mortality risk. We have not achieved a predictive model that combines hormones with inflammatory markers.

What is thyroid function in your just-diagnosed cancer patient?

The principal hormonal product of the thyroid gland, L-thyroxine (T4), is a prohormone for 3,3',5-triiodo-L-thyronine, T3, the major ligand of nuclear thyroid hormone receptors (TRs). At a cell surface thyroid hormone analogue receptor on cancer cell and endothelial cell plasma membrane integrin αvβ3, however, T4 at physiological concentrations is biologically active and is the major ligand. At this site in solid tumor cells, T4 nongenomically initiates cell proliferation, is anti-apoptotic by multiple mechanisms, supports radioresistance and enhances cancer-related angiogenesis. In contrast, hypothyroidism has been reported clinically to slow tumor growth. At physiological levels, T3 is not biologically active at the integrin and maintenance of euthyroidism with T3 in cancer patients may be associated with slowed tumor proliferation. Against this background, we raise the possibility that host serum T4 levels that are spontaneously in the upper tertile or quartile of the normal range in cancer patients may be a factor that contributes to aggressive tumor behavior. Recent observations on tumor metastasis and tumor-associated propensity for thrombosis due to T4 also justify clinical statistical analysis for a relationship to upper tertile hormone levels. That reverse T3 (rT3) may stimulate tumor growth has recently been reported and thus the utility of adding this measurement to thyroid function testing in cancer patients requires assessment. In summary, T4 at physiological concentrations promotes tumor cell division and aggressiveness and euthyroid hypothyroxinemia arrests clinically advanced solid tumors. These findings support the clinical possibility that T4 levels in the upper tertile of the normal range require examination as a tumor supporting factor.

Iodine in the Therapy of Graves' Disease: A Century After Henry S. Plummer.

N/A.

DIO1 Gene Polymorphism Is Associated with Thyroid Profiles and Reproductive Performance in Dairy Cows

Thyroid hormones mediate the interaction between the metabolic and reproductive systems, while their metabolism is controlled by different deiodinases. The present study aimed to search for associations of cow genotypes with SNPs in the deiodinase type 1 gene (DIO1) with thyroid profiles and reproductive traits. The blood was sampled from Russian black-and-white cows 2–6 weeks before calving and 1–13 weeks after calving to measure the hormonal levels by ELISA. RT-PCR analysis was performed for known mutations in the bovine DIO1 gene, and a polymorphism at position 13,149 was found. In animals with the CG genotype, the blood concentration of reverse triiodothyronine 6 weeks prepartum was higher and decreased much earlier than in animals with the CC genotype. Furthermore, 1 week after calving, the total triiodothyronine to reverse triiodothyronine ratio in cows with the CG genotype was higher than in cows with the CC genotype. A higher proportion of animals with better values of fertility traits was revealed in the CC group compared to the CG group. Thus, cows with the CC genotype of the DIO1 gene more often have a high reproductive ability, which may be associated with the rT3 profile features during the prepartum and early postpartum periods.

The Effect of Long-Term Inorganic Iodine on Intrathyroidal Iodothyronine Content and Gene Expression in Mice with Graves' Hyperthyroidism.

Background: The main molecular mechanism underlying acute suppression of iodine organification in normal thyroids after an excessive iodine load, that is, the Wolff-Chaikoff effect, is assumed to be suppression of iodine oxidation and iodothyronine synthesis. However, the mechanism underlying chronic antithyroid action of inorganic iodine in Graves' disease is not fully understood. Using a mouse model of Graves' hyperthyroidism, we examined changes in iodothyronine content and gene expression profiles in the thyroid glands after inorganic iodine loading. Materials and Methods: Graves' hyperthyroidism was induced and maintained in BALB/c mice by repeated immunizations of recombinant adenovirus expressing the human thyrotropin (TSH) receptor A-subunit. Hyperthyroid mice were left untreated (GD-C; n = 8) or treated with inorganic iodine for 12 weeks (GD-NaI; n = 8). We used unimmunized BALB/c mice as a control group (n = 10). In each mouse, serum thyroxine (T4) levels were measured with enzyme-linked immunosorbent assay (ELISA) at 4-week intervals. The intrathyroidal iodothyronine content and gene expression levels were, respectively, evaluated by mass spectrometry and RNA sequencing (RNA-seq) at the end of the experimental period. Results: Serum T4 levels in the GD-C group remained higher than in the control group, whereas those in the GD-NaI group declined to normal levels during the experimental period. Intrathyroidal triiodothyronine (T3), reverse T3 (rT3), and T4 contents in the GD-C group were higher than the control group, and rT3 and T4 were further increased in the GD-NaI group. The observed alterations in iodothyronine levels in the thyroid and sera may be explained by altered expression levels of genes for iodothyronine biosynthetic molecules, their transporter, and deiodinases. Conclusion: In this mouse model of hyperthyroidism, higher intrathyroidal accumulation of T4 and reduced gene expression data of iodothyronine transporters in the GD-NaI group suggest that chronic antithyroid action of iodine in Graves' disease involves suppression of hormone secretion.

Association of SNP localized near &lt;i&gt;DIO2&lt;/i&gt; gene with hormonal profiles of the thyroid axis and fertility indicators in black-and-white cows

Thyroid hormones can affect the reproductive function of cows through the regulation of various metabolic pathways. The activity of the thyroid system is under the control of three types of deiodinases (DIO). In cattle, there are several genetic variants for the DIO1 and DIO3 genes, but there is no information on the polymorphism of the DIO2 gene.Purpose: to conduct a search for genetic variants for SNPs in the DIO2 gene and in nearby regions and investigate their association with prepartum and postpartum thyroid profiles and reproductive performance in dairy cows.Materials and methods. Black-and-white cows of calving 2-4 were used in the experiments. Before calving and after calving, blood was taken from the animals to determine the concentration of hormones by ELISA. The assessment of the luteal activity of the ovaries was performed on the basis of an ultrasound study and the content of progesterone in the blood. Genotyping was performed on 48 samples of cow DNA using a Bovine GGP 150K biochip.Results. No SNPs present on the Bovine GGP 150K chip were found within the target gene. The SNP Bovine- HD1000026761, localized upstream of the DIO2 gene, was selected for research, with a frequency of genotypes being 45.83% (AA), 47.92% (AG), and 6.25% (GG). In cows with the AA and AG genotypes, a decrease of 1.4 times (p&lt;0.01) in the blood concentration of total thyroxine (T4) 2 weeks before calving, compared with that for 4 weeks, and its further decrease by 1.5 -1.9 times (p&lt;0.001-p&lt;0.05) by the 1st week of lactation were found. From the 6th to the 2nd week before parturition, this indicator was 1.5–1.6 times higher (p&lt;0.001–p&lt;0.05) in individuals with the AG genotype than in ones with the AA genotype. In animals with the AG genotype, a decrease in the blood concentration of reverse T3 (1.4 times, p&lt;0.05) between the 4th week before calving and the 1st week of lactation was revealed. At the same time, this concentration was relatively constant in the animals of the other two groups. Furthermore, in animals with the AG genotype, the content of rT3 in the blood was 1.3 times lower than in animals with the AA genotype from the 3rd to the 7th week of lactation. In cows with a heterozygous genotype, the T4/T3 ratio increased 2.1 times (p&lt;0.001) between the 2nd week before calving and the 1st week after calving, and then decreased 2.2 times (p&lt;0.001) to the 3rd week. After 1 week of lactation, this ratio was 1.9 times higher (p&lt;0.001) than in animals with the AA genotype. Meanwhile, the frequency of occurrence of individuals with the shortest period of recovery of the ovarian function and open days period was the lowest in the group with the AA genotype.Conclusions. The data obtained indicate that the SNP BovineHD1000026761, located upstream of the DIO2 gene, is associated with long-term changes in thyroid hormone levels in the prepartum and postpartum periods.

INFORMATION ON PROGNOSTIC MARKERS OF SEVERE ACUTE BRONCHITIS IN PRESCHOOLERS: A STUDY IN SUMY REGION IN NORTH-EASTERN UKRAINE

Introduction. Respiratory infections, especially in children, are a significant global health concern. Understanding the implications of respiratory infections like acute bronchitis is crucial for devising effective management strategies. These infections, including bronchitis, pneumonia, and influenza, contribute substantially to pediatric hospitalizations. Predicting the severity of acute bronchitis in children is essential for personalized treatment and resource allocation. Developing reliable prognostic tools for acute bronchitis can improve outcomes and optimize healthcare resource utilization. Methods. The study spanned four years (2018–2021) at "Saint Zinaida's Children's Clinical Hospital" and "Primary Health Care Center No. 2" in Sumy City Council. It involved 135 preschool children with acute bronchitis (study group) and 28 healthy children (control). The control group matched the age and gender of the acute bronchitis group. Inclusion criteria comprised parental consent, ages 3–6, and a diagnosis of acute bronchitis; exclusions included parental refusal, ages below 3 or above 7, concurrent somatic or allergic diseases, non-compliance, and diagnoses other than acute bronchitis. Various methods were employed, including clinical, laboratory, instrumental, and statistical analyses. The severity of acute bronchitis was gauged using the BSS-ped clinical tool. Immunological status assessment involved determining cellular immunity indicators via enzyme-linked immunosorbent assay. Hormonal status analysis included thyroid and cortisol levels via enzyme-linked immunosorbent assay. Statistical analysis utilized SPSS 26 and probabilistic modeling based on Bayes' theorem for building prognostic models and assessing risk factors for acute bronchitis. Fisher's criterion determined reliability at a significance level of 0.05, categorizing risk degrees from low to critically high based on a posteriori chances. Results. The study successfully identified key clinical, anamnestic, hormonal, and immunological risk factors for severe acute bronchitis in preschoolers, constructing a predictive mathematical model. Breastfeeding and mixed feeding in infants were not associated with increased severity, contrasting with chronic upper respiratory tract disease and parental habits, notably smoking, linked to heightened severity. Cough severity and auscultatory wheezing, with a BSS-ped score of 4, moderately impacted severe acute bronchitis. An outlined prognostic model confirmed hormonal indicators' influence, particularly elevated reverse triiodothyronine levels, on increased risk. Immune cellular activity, specifically CD8+, CD4+, and CD22+, demonstrated pronounced impacts on severe acute bronchitis in preschoolers. A combined aberration of CD3+ and free triiodothyronine, CD3+ and total triiodothyronine, or CD4+ and free triiodothyronine indicated a critically high risk. The model's reliability was affirmed via ROC analysis, displaying a sensitivity of 91.7 %, specificity of 68.2 %, and an AUC of 0.869, indicating its high quality. Conclusions. In summary, chronic upper respiratory tract disease and parental smoking, particularly when both parents smoke, are significant clinical and anamnestic risk factors for severe acute bronchitis in preschoolers. Cough severity and wheezing on the BSS-ped scale contribute to its development. Hormonal indicators, especially reverse triiodothyronine, display notable impacts, with weaker associations observed for total triiodothyronine and cortisol. Immunological status indicators such as CD22+, CD4+, and CD8+ are also linked to severe acute bronchitis. Combinations of altered CD4+ and free triiodothyronine, CD3+ and free triiodothyronine, CD3+ and total triiodothyronine intensify the risk. When evaluating preschoolers with acute bronchitis, attention to clinical history (chronic upper respiratory disease, parental smoking, severe cough, and pulmonary rales) and specific laboratory parameters (concentration of triiodothyronine, cortisol, and serum levels of CD22+, CD4+, and CD8+) is advisable.

Long-term effect of a large dose of iodinated contrast in patients with mild thyroid dysfunction: a prospective cohort study.

More than 75 million procedures with intravascular iodine-based contrast media (ICM) are performed worldwide every year, and some patients undergoing these procedures do not have normal thyroid function. The long-term effects of ICM in patients with mild thyroid dysfunction (TD) are unclear. This prospective cohort study was conducted in China. Patients with stable angina pectoris with total triiodothyronine (TT3) reduction, normal thyroid-stimulating hormone, and reverse triiodothyronine (rT3) were enrolled and divided into high-dose (≥100 mL ICM) and low-dose groups (<100 mL ICM). We dynamically investigated the trends in thyroid function, rT3, and thyroid antibodies 1 year after ICM exposure. A total of 154 patients completed 6 months of follow-up and 149 completed 1 year of follow-up. Thyroglobulin antibody (TGAB) levels were elevated in 41 (26.6%) patients before ICM exposure, 11 (7.1%) of whom also had elevated thyroid peroxidase antibody levels. Transient subclinical TD occurred 6 months after ICM exposure; 75.5% of post-operative TD occurred in the high-dose group. One patient developed severe hypothyroidism with myxedema, requiring drug intervention 1 year after ICM exposure. The level of rT3 showed no statistically significant changes during post-operative follow-up (P = 0.848). The TGAB level decreased at 6th month (P < 0.001), but increased at 1 year after ICM exposure (P = 0.002). Patients with T3 reduction are at risk of transient subclinical TD and hypothyroidism after a single large dose of ICM. Follow-up of this population at 9-12 months after ICM exposure is warranted.

Frequency of non-thyroidal illness syndrome in pediatric patients with sepsis and septic shock

BackgroundNon-thyroidal illness syndrome (NTIS) is considered when patients demonstrate altered thyroid hormones and is frequently seen in patients with sepsis and septic shock. Levels keep affected with disease progression and usually get normalized after the sickness is cured. NTIS is not studied well in pediatric population.Aim of the workOur primary outcome was to assess the frequency of hormonal changes of NTIS in sepsis and septic shock patients. The secondary outcome was to follow-up the severity of NTIS and its effect on the prognosis of the primary illness.Patients and methodsThis study (1st phase: cross-sectional, 2nd phase: prospective) included 40 critically ill children categorized into two groups: (i) sepsis group: defined according to standard international criteria using pediatric Sequential Organ Failure Assessment (p SOFA) score and sepsis was considered when p SOFA score > 2; (ii) septic shock group: defined by a vasopressor requirement to maintain a mean arterial pressure ≥ 65 mmHg and having a serum lactate level > 2 mmol/L despite adequate fluid resuscitation, with 20 patients in each group. Patients were admitted to the pediatric intensive care unit (PICU). Thyroid hormone levels were assessed and compared in day 1 and day 5 in all patients and subgroups. All patients were followed up until discharge or death.ResultsNTIS was found in 47.5% of patients. NTIS was higher among septic shock group than sepsis 65.5% versus 30% (p = 0.027). NTIS was associated with each of ventilation, catecholamines infusion and SOFA score (p = 0.044, 0.027, and 0.033) respectively. FT3 (free triiodothyronine) levels were lower and rT3 (reverse T3) levels were higher in day 5 of sickness than day 1 (p = 0.041 and 0.000) respectively. Furthermore, FT3 levels in day 5 were lower, and rT3 levels in day 1 and day 5 were higher in non-survivors than survivors (p = 0.002, 0.015, and 0.003) respectively. ROC curve was done to assess predictors of mortality and revealed that FT3 levels in day 5 was the best in predicting PICU mortality, followed by SOFA score day 5.ConclusionNTIS is common among critically ill children and higher among septic shock group than sepsis. Also, beside the SOFA score, FT3 measured in day 5 of sickness were the best predictors of PICU mortality.

Allan-Herndon-Dudley syndrome: Report of a novel pathogenic variant in MCT8 gene

X-linked MCT8 mutations cause Allan-Herndon-Dudley syndrome (AHDS) characterized by severe developmental delay and specific thyroid function abnormality. The report describes a 1 year-old boy with severe developmental delay, truncal hypotonia, quadriparesis (spastic), dystonia, and thyroid function abnormality (high free T3, low reverse T3, low free T4, and normal TSH) suggesting a form of impaired thyroid hormone sensitivity, namely, AHDS. WES analysis yielded novel hemizygous single-base pair duplication in exon 1 of MCT8 gene, validated by Sanger sequencing. MRI revealed generalized demyelination with poor gray and white matter differentiation and loss of brain volume. Indirect markers revealed thyrotoxicosis in some peripheral tissues. Having high index of suspicion for this rare disorder and plausible benefit of inclusion of free T3 assay in initial evaluation of infants and children with idiopathic developmental delay are emphasized. Amelioration of thyrotoxic features with tri-iodothyroacetic acid likely benefits patients at all ages. Neurodevelopmental improvement has been observed in those who received tri-iodoacetic acid early, which is being currently investigated.

Abstract 15293: Predictive Value of Thyroid Hormone Levels in Patients Suffering From Cardiogenic Shock Complicating Acute Myocardial Infarction

Hypothesis: Introduction. Acute critically ill patients experience a rapid decline in plasma free thyroid hormone levels (free triiodothyronine (FT3) and free levothyroxine (FT4)), with a marked elevation of reverse T3, recognized as the euthyroid sick syndrome (ESS) or low-T3 syndrome. The ESS is also often associated with depressed myocardial function, sometimes referred to as the 'stunned myocardium. The role of thyroid hormone levels in patients with cardiogenic shock complicated myocardial infarction has not been shown Methods: The purpose of the study was to assess the impact of thyroid hormone levels on hospital mortality in patients with infarction related cardiogenic shock. Thyroid hormone levels were measured from routine blood specimens and analyzed initial and up to 96 hours. Results: We identified 40 patients with infarction related cardiogenic shock treated at our university hospital. Majority of the CS-patients had on admission reduced TSH levels of 1,42 ± 0,22mU/l. Nevertheless, in-hospital mortality rate was higher in patients with lower admission TSH levels and levels over time. In addition, FT3 in CS-survivors showed a flat slope from normal levels. Non-survivor had a trend towards lower levels after 72 and 96 hours. When we analyzed for low T3 syndrome (i.e. FT3 &gt;3,1pmol/l) we saw a 3x times higher mortality rate compared to CS patients with normal levels. In contrast, FT4 levels of non survivors were significantly elevated compared to surviving CS patients. After 96 hours both groups had similar levels. Predictors of hospital death in CS patients were low TSH levels, low T3 syndrome and elevated FT4. Conclusions: Thyroid hormone level on admission and over time (i.e. low TSH, low T3 and elevated FT4) are predictors of in-hospital death in patients with infarction related cardiogenic shock. Interestingly TSH stays almost stable over time whereas FT3 and FT4 declines over time. Further studies have to show if administration of thyroid hormone might be beneficial in patients with infarction related cardiogenic shock.

ODP479 Equilibrium Dialysis ID-LC/MS/MS Procedure for Routine Measurement of Free Thyroxine in Serum

Abstract Free thyroxine (FT4) test is essential for diagnosis of thyroid diseases. Most FT4 tests used in patient care are immunoassays (IAs). However, concerns about the accuracy of FT4 IAs have been raised in the clinical laboratory community. Reference measurement procedure (RMP) for FT4 based on well-defined equilibrium dialysis (ED) of serum has been established and are well recognized. While FT4 RMP is highly accurate and precise, it is not intended for routine clinical use. Our aim is to develop an ED-based FT4 assay that is traceable to the RMP and suitable for routine measurements such as investigations in epidemiologic studies. The described assay is based on ED-LC-MS/MS. FT4 in serum was isolated from protein-bound T4 in serum according to the CLSI C45-A guideline. FT4 levels achieved equilibrium in a commercially available micro-ED plate after 18 hours. The dialysate was collected and spiked with internal standard (13 C 6 -T4). The IRMM-468 certified primary reference material (JRC, Belgium) of T4 was used for assay calibration. FT4 in dialysate was extracted with ISOLUTE-96-well C18 SPE plates (Biotage) before LC-MS/MS analysis. T4 could be resolved from Triiodothyronine (T3), reverse triiodothyronine (rT3), and other interferences in the dialysate on a C18 UPLC column with an elution time of less than 8 min. Selective reaction monitoring in positive electrospray ionization mode was used for detection. The measuring range covered 1-100 pg/mL of FT4. The assay sensitivity allowed detection of 0.5 pg/mL FT4, which is sufficient for detection of FT4 in normal and hypothyroid patient samples. The difference of this method to the CDC FT4 RMP was within ±5%. The imprecision of the routine assay, evaluated over four different days, was less than 10% CV. The slopes of calibration curves in dialysate matrix and water were comparable with each other indicating no significant matrix effect on FT4 quantification. The use of micro-ED plates in combination with an automated liquid handling system allows for effective automation of the procedure. The stability of T4 calibrator stock and working solutions were confirmed at various conditions. Currently, a comprehensive comparison study is underway between the newly developed routine method and the CDC FT4 RMP. The described routine FT4 assay can significantly improve throughput. The sensitivity, precision, and accuracy are suitable for routine FT4 measurements in clinical laboratories and conducting large epidemiologic studies. Applying this FT4 routine method to generate population data will support the use of standardized FT4 measurements and to address data needs on FT4 in general population. Presentation: No date and time listed

RF10 | PMON215 Greater changes in metabolic hormones are associated with a smaller decrease in pulsatile LH secretion in response to short term moderate energy restriction in healthy, young women

Abstract Background Energy restriction may result in hypothalamic amenorrhea by inhibiting GnRH secretion and downstream pulsatile LH secretion. Energy restriction also leads to adaptive changes in metabolic hormones. We sought to determine whether metabolic changes in response to energy restriction predict or mitigate inhibition of GnRH secretion. Methods Nineteen healthy women, (mean age ± SD; 23.36 ± 2.08 yrs) with regular ovulatory cycles and no evidence of energy restriction or excessive exercise, underwent two 5-day dietary interventions with identical exercise in the early follicular phase of two menstrual cycles. A neutral energy availability (NEA; 45 kCal/kg*LBM/d) was followed by a deficient energy availability (DEA; 20 kCal/kg*LBM/d) diet. On day five of each intervention, body composition was analyzed (BodPod®), and blood was sampled between 0800 —1600 hours for LH, TSH and GH, every 10 min, cortisol every 30 min, T3, reverse T3 (rT3) and T4 every 60 min, free T3 (FT3), free T4 (FT4) and TBG at 0800 h and 1600 h. We correlated means of pulsatile LH pulse frequency (LHPF) with integrated metabolic hormone changes across the day in the subset of women with reduced or unchanged LHPF after DEA (n=10) using linear regression. Results In ∼50% of healthy young women, LHPF decreased or was unchanged in response to short-term moderate energy deprivation. BMI and bodyweight declined after DEA in both groups while % fat mass was unchanged. TSH, T3, leptin, insulin declined, and T4 increased from NEA to DEA while glucose, cortisol and GH were unchanged. In subjects with reduced/unchanged LHPF, % delta T3 correlated inversely with delta LHPF (r=-0.727, p=0.017). Similarly, non-fasting delta TSH correlated inversely with % delta LHPF (r=-0.643, p=0.045), and % delta AUC TSH (r=-0.642, p=0.045) correlated inversely with DEA LHPF. Percent delta insulin (r= -0.722, p=0.018) and % delta insulin AUC (r= – 0.688, p=0.028) correlated inversely with delta LHPF. Percent delta insulin-glucose ratio (r=-0.772, p=0.009) and % change in AUC insulin-glucose ratio (r=-0.759, p=0.011) also correlated inversely with delta LHPF. This inverse relationship was preserved when insulin was normalized for caloric intake (n-insulin) was correlated with % delta LHPF (r=-0.722, p=0.018) and % delta AUC n-insulin correlated with delta LHPF (r= -0.631 and p= 0.050). Delta AUC leptin (r=-0.684, p=0.029) and % delta AUC leptin (r=-0.670, p=0.034) also correlated inversely with delta LHPF. Mean cortisol at NEA correlated inversely with LHPF during DEA (r=-0.816, p=0.007), implying that higher baseline cortisol levels may predict a greater relative fall in LHPF. Cortisol AUC in DEA also correlated inversely with LHPF in DEA (r=-0.722, p=0.028). Conclusion Our data suggest that greater changes in metabolic hormones may protect against the inhibitory effect of moderate energy deprivation on GnRH secretion in healthy young women with normal reproductive function. Presentation: Saturday, June 11, 2022 1:30 p.m. - 1:35 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.