The molecular basis of the non-thyroidal illness syndrome

TRβ activation confers AT2-to-AT1 cell differentiation and anti-fibrosis during lung repair via KLF2 and CEBPA

Aberrant repair underlies the pathogenesis of pulmonary fibrosis while effective strategies to convert fibrosis to normal regeneration are scarce. Here, we found that thyroid hormone is decreased in multiple models of lung injury but is essential for lung regeneration. Moreover, thyroid hormone receptor α (TRα) promotes cell proliferation, while TRβ fuels cell maturation in lung regeneration. Using a specific TRβ agonist, sobetirome, we demonstrate that the anti-fibrotic effects of thyroid hormone mainly rely on TRβ in mice. Cellularly, TRβ activation enhances alveolar type-2 (AT2) cell differentiation into AT1 cell and constrains AT2 cell hyperplasia. Molecularly, TRβ activation directly regulates the expression of KLF2 and CEBPA, both of which further synergistically drive the differentiation program of AT1 cells and benefit regeneration and anti-fibrosis. Our findings elucidate the modulation function of the TRβ-KLF2/CEBPA axis on AT2 cell fate and provide a potential treatment strategy to facilitate lung regeneration and anti-fibrosis.

A national survey of iodine nutrition in children aged 3-6 years in China and its relationship with children's physical growth

Iodine, an essential trace element for the human body, plays a pivotal role in sustaining health. Malnutrition has emerged as a pressing public health concern, posing a significant threat to human well-being. Iodine deficiency poses a substantial threat to the development of children, potentially leading to neurological developmental disorders and mental retardation. Conversely, excessive iodine intake can result in structural and functional abnormalities in the thyroid gland. In this study, we selected children aged 3-6 years through a stratified cluster sampling approach in six regions across China to explore the correlation between iodine nutrition and their physical growth. A total of 5920 preschool children participated in this study, with a median urinary iodine concentration (UIC) of 177.33 [107.06, 269.92] μg/L. Among these children, 250 (4.2%) exhibited stunting, 180 (3.0%) were underweight, 198 (3.3%) experienced wasting, 787 (3.3%) were overweight and 414 (7.0%) were classified as obese. The multivariate linear regression revealed that UIC exhibited a positive correlation with body mass index z-Score (BMIZ) in overweight children (β = 0.038; 95% CI: 0.001, 0.075). In normally growing children, the associations between UIC and height-for-age z-score, weight-for-age z-score and BMIZ displayed nonlinear patterns. Our findings suggest that iodine nutrition is adequate for Chinese children aged 3-6 years. Furthermore, iodine nutrition is intricately linked to the growth and development of these children. Consequently, it is imperative to implement decisive measures to prevent both iodine deficiency and excess.

Cytokine Storm-Induced Thyroid Dysfunction in COVID-19: Insights into Pathogenesis and Therapeutic Approaches

Angiotensin-converting enzyme 2 receptors (ACE2R) are requisite to enter the host cells for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). ACE2R is constitutive and functions as a type I transmembrane metallo-carboxypeptidase in the renin-angiotensin system (RAS). On thyroid follicular cells, ACE2R allows SARS-CoV-2 to invade the thyroid gland, impose cytopathic effects and produce endocrine abnormalities, including stiff back, neck pain, muscle ache, lethargy, and enlarged, inflamed thyroid gland in COVID-19 patients. Further damage is perpetuated by the sudden bursts of pro-inflammatory cytokines, which is suggestive of a life-threatening syndrome known as a "cytokine storm". IL-1β, IL-6, IFN-γ, and TNF-α are identified as the key orchestrators of the cytokine storm. These inflammatory mediators upregulate transcriptional turnover of nuclear factor-kappa B (NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), and mitogen-activated protein kinase (MAPK), paving the pathway for cytokine storm-induced thyroid dysfunctions including euthyroid sick syndrome, autoimmune thyroid diseases, and thyrotoxicosis in COVID-19 patients. Targeted therapies with corticosteroids (dexamethasone), JAK inhibitor (baricitinib), nucleotide analogue (remdesivir) and N-acetyl-cysteine have demonstrated effectiveness in terms of attenuating the severity and frequency of cytokine storm-induced thyroid dysfunctions, morbidity and mortality in severe COVID-19 patients. Here, we review the pathogenesis of cytokine storms and the mechanisms and pathways that establish the connection between thyroid disorder and COVID-19. Moreover, cross-talk interactions of signalling pathways and therapeutic strategies to address COVID-19-associated thyroid diseases are also discussed herein.

Genetic effect of thyroid function-related diseases on acute respiratory distress syndrome: a Mendelian randomization study

BACKGROUND

Previous studies have shown an association between acute respiratory distress syndrome (ARDS) and thyroid function. However, their causal relationship remains unspecified. Therefore, this study aims to explore the causal relationship between ARDS and thyroid function-related diseases with Mendelian Randomization (MR) analysis.

METHODS

ARDS dataset finn-b-J10_ARDS, finn-b-E4_THYROID dataset of disorders of the thyroid gland (DTG) and finn-b-E4_HYTHYNAS of hypothyroidism were acquired from public database. In univariate MR (UVMR), causal effects between DTG, hypothyroidism and ARDS were investigated using 5 types of algorithms, and reliability was validated by sensitivity analysis. Moreover, multivariate MR (MVMR), enrichment and interaction network analyses of genes corresponding to SNPs of DTG and hypothyroidism were carried out. Significant level was chosen as p<0.05.

RESULTS

UVMR identified DTG and hypothyroidism (P < 0.05, OR > 1) as risk factors, and were causally related to ARDS. Reliability of UVMR results was confirmed through sensitivity analysis, and results were stable and reliable. However, DTG and hypothyroidism had no effect on ARDS in MVMR, possibly because these factors had independent effects on ARDS. Ultimately, 96 and 113 genes corresponding to SNPs of DTG and hypothyroidism were found closely related to immune-related pathways.

CONCLUSIONS

UVMR and MVMR analysis revealed a causal connection between DTG and hypothyroidism as risk factors with ARDS, providing robust evidence for investigation into relationship of hypothyroidism on ARDS and between DTG and ARDS.

[Related factors of euthyroid sick syndrome in patients with sepsis]

OBJECTIVE

To evaluate the prevalence of euthyroid sick syndrome (ESS) in sepsis patients and to explore its influencing factors.

METHODS

In the study, 365 patients diagnosed with sepsis in the emergency critical care department of Shanghai First People's Hospital from January 2017 to January 2023 were retrospectively enrolled. The patients were divided into ESS and non-ESS groups based on whether the patients were complicated with ESS.Baseline variables and relevant clinical data of the enrolled patients were collected. The prevalence of ESS in sepsis patients and its influencing factors were evaluated by multivariate Logistic regression analysis, and the 30-day survival rates were compared between the two groups. The optimal cutoff value for free triiodothyronine (FT3) was explored to predict death in the patients with sepsis.

RESULTS

There were 103 sepsis patients with ESS, accounting for 28.2% of the total cases. The severity of sepsis in ESS group was significantly higher than that in non-ESS group (P < 0.05). The acute physiology and chronic health evaluationⅡ(APACHEⅡ)score and sequential organ failure assessment (SOFA) score of ESS group were significantly higher than those of non-ESS group (P < 0.05). C-reactive protein (CRP), procalcitonin (PCT), serum amyloid A (SAA) and interleukin-6 (IL-6) in ESS group were higher than those in non-ESS group. total cholesterol(TC)and high-density liptein cholesterol(HDL-C)in ESS group were lower than those in non-ESS group, and the differences were statistically significant (P < 0.05).Multivariate Logistic regression analysis showed that PCT, IL-6, CRP, SAA and activated partial thromboplatin time (APTT) were independent risk factors for ESS in the sepsis patients (OR values were 1.105, 1.006, 1.005, 1.009 and 1.033, respectively; 95% CI were 1.044-1.170, 1.001-1.012, 1.001-1.009, 1.005-1.014, 1.004-1.062, respectively, P < 0.05).The 30-day survival rate in ESS group was significantly lower than that in non-ESS group, the Long-rank chi-square test value was 16.611, and the difference was statistically significant (P < 0.05).The receiver operation characteristic area under the curve (AUCROC)of FT3 predicted death in the patients with sepsis was 0.924 (95% CI 0.894-0.954). The serum FT3 cutoff point was 3.705 pmol/L, the specificity was 0.868, and the sensitivity was 0.950.

CONCLUSION

In this study, the incidence of ESS in sepsis patients was determined to be 28.2% with poor prognosis. The results showed that PCT, IL-6, CRP, SAA and APTT were independent risk factors for ESS in sepsis patients, while HDL-C was a protective factor (P < 0.05). FT3 is a novel potential biomarker for predicting death in patients with sepsis.

A DIO2 missense mutation and its impact on fetal response to PRRSV infection

BACKGROUND

Porcine reproductive and respiratory syndrome virus 2 (PRRSV-2) infection during late gestation substantially lowers fetal viability and survival. In a previous genome-wide association study, a single nucleotide polymorphism on chromosome 7 was significantly associated with probability of fetuses being viable in response to maternal PRRSV-2 infection at 21 days post maternal inoculation. The iodothyronine deiodinase 2 (DIO2) gene, located ~ 14 Kilobase downstream of this SNP, was selected as a priority candidate related to fetal susceptibility following maternal PRRSV-2 infection. Our objectives were to identify mutation(s) within the porcine DIO2 gene and to determine if they were associated with fetal outcomes after PRRSV-2 challenge. Sequencing of the DIO2, genotyping identified variants, and association of DIO2 genotypes with fetal phenotypes including DIO2 mRNA levels, viability, survival, viral loads, cortisol and thyroid hormone levels, and growth measurements were conducted.

RESULTS

A missense variant (p.Asn91Ser) was identified in the parental populations from two independent PRRSV-2 challenge trials. This variant was further genotyped to determine association with fetal PRRS outcomes. DIO2 mRNA levels in fetal heart and kidney differed by the genotypes of Asn91Ser substitution with significantly greater DIO2 mRNA expression in heterozygotes compared with wild-type homozygotes (P < 0.001 for heart, P = 0.002 for kidney). While Asn91Ser did not significantly alter fetal viability and growth measurements, interaction effects of the variant with fetal sex or trial were identified for fetal viability or crown rump length, respectively. However, this mutation was not related to dysregulation of the hypothalamic-pituitary-adrenal and thyroid axis, indicated by no differences in circulating cortisol, T4, and T3 levels in fetuses of the opposing genotypes following PRRSV-2 infection.

CONCLUSIONS

The present study suggests that a complex relationship among DIO2 genotype, DIO2 expression, fetal sex, and fetal viability may exist during the course of fetal PRRSV infection. Our study also proposes the increase in cortisol levels, indicative of fetal stress response, may lead to fetal complications, such as fetal compromise, fetal death, or premature farrowing, during PRRSV infection.

Impact of thyroid hormone replacement therapy on the course and functional outcome of aneurysmal subarachnoid hemorrhage

BACKGROUND

Thyroid hormones were reported to exert neuroprotective effects after ischemic stroke by reducing the burden of brain injury and promoting post-ischemic brain remodeling.

OBJECTIVE

We aimed to analyze the value of thyroid hormone replacement therapy (THRT) due to pre-existing hypothyroidism on the clinical course and outcome of aneurysmal subarachnoid hemorrhage (SAH).

METHODS

SAH individuals treated between January 2003 and June 2016 were included. Data on baseline characteristics of patients and SAH, adverse events and functional outcome of SAH were recorded. Study endpoints were cerebral infarction, in-hospital mortality and unfavorable outcome at 6 months. Associations were adjusted for outcome-relevant confounders.

RESULTS

109 (11%) of 995 individuals had THRT before SAH. Risk of intracranial pressure- or vasospasm-related cerebrovascular events was inversely associated with presence of THRT (p = 0.047). In multivariate analysis, THRT was independently associated with lower risk of cerebral infarction (adjusted odds ratio [aOR] = 0.64, 95% confidence interval [CI] = 0.41-0.99, p = 0.045) and unfavorable outcome (aOR = 0.50, 95% CI = 0.28-0.89, p = 0.018), but not with in-hospital mortality (aOR = 0.69, 95% CI = 0.38-1.26, p = 0.227).

CONCLUSION

SAH patients with THRT show lower burden of ischemia-relevant cerebrovascular events and more favorable outcome. Further experimental and clinical studies are required to confirm our results and elaborate the mechanistic background of the effect of THRT on course and outcome of SAH.

An unusual evolution of thyroid function after therapeutic plasma exchange in Graves' disease with cholestatic jaundice: A case report

RATIONALE

Methimazole (MMI) is the first-line agent in the treatment of hyperthyroidism. However, rare but severe cholestatic jaundice may occur. Therapeutic plasma exchange (TPE) may provide an alternative treatment for such patients and they received thyroidectomy/radioactive iodine ablation or continued oral anti hyperthyroidism medication immediately after TPE session in the reported literatures. The case reported here is, to our knowledge, the first to describe the long interval between anti hyperthyroidism therapy and TPE in such patients.

PATIENT CONCERNS

A 49-year-old Chinese woman had developed worsening jaundice 3 weeks after receiving methimazole (20 mg/day) for the treatment of hyperthyroidism secondary to Graves' disease (GD). Additionally, she had a 2-year history of type 2 diabetes.

DIAGNOSIS

Hyperthyroidism secondary to GD, MMI-induced severe cholestatic jaundice and type 2 diabetes.

INTERVENTIONS

Methimazole was discontinued and the patient received 3 times of TPE, about 3-month glucocorticoid treatment, insulin administration accordingly and other conventional liver-protecting therapy.

OUTCOMES

Her thyroid function was stabilized with small dose of thyroxine substitution and euthyroid status persisted after thyroxine discontinuation until hyperthyroidism recurred 7 months later while her cholestatic jaundice was eventually recovered by about 3-month glucocorticoid therapy.

LESSONS

Due to the complex interplay between liver function and thyroid hormones, there may be unusual changes of thyroid function in GD patients with severe liver injury after TPE. By this case, we want to highlight the importance of a closely following up of thyroid function in order to deliver appropriate health suggestions for patients.

Impact of metformin on hypothalamic-pituitary-thyroid axis activity in women with autoimmune and non-autoimmune subclinical hypothyroidism: a pilot study

BACKGROUND

Metformin reduces plasma TSH levels if these levels are elevated. No study has investigated whether the hormonal effects of metformin are impacted by thyroid autoimmunity. The current study aimed to compare the effect of metformin on hypothalamic-pituitary-thyroid axis activity between subjects with mild hypothyroidism of different origins.

METHODS

The study population consisted of two groups of women with prediabetes and mildly elevated TSH levels, matched by age, insulin sensitivity, TSH, and thyroid hormone levels. Group A included 26 women with autoimmune thyroiditis, while group B enrolled 26 individuals with hypothyroidism of non-autoimmune origin. Both groups were treated with metformin (2.55-3 g daily). Circulating levels of TSH, total and free thyroid hormones, glucose, insulin, prolactin, high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D, concentrations of thyroid antibodies, and structure parameters of thyroid homeostasis were assessed at baseline and 6 months later.

RESULTS

All patients completed the study. At baseline, both groups differed in concentrations of thyroid peroxidase antibodies, thyroglobulin antibodies, hsCRP, and 25-hydroxyvitamin D. The drug reduced TSH and Jostel's index, with no difference between the study groups. The improvement in insulin sensitivity, observed in both groups, was more pronounced in group B than in group A. In women with autoimmune hypothyroidism, the drug increased SPINA-GT and decreased hsCRP levels. The remaining markers did not change throughout the study.

CONCLUSIONS

The obtained results suggest that, despite differences in thyroid output, the impact of metformin on TSH levels is similar in hypothyroid women with and without thyroid autoimmunity.

Circulating thyroid hormones and clinical parameters of heart failure in men

Heart failure (HF) is a multiple hormonal deficiency syndrome which includes alterations in the serum concentration of thyroid hormones (TH). This cross-sectional study enrolled 215 male patients hospitalised for acute HF. Data on cardiovascular risk factors, chronic medications, cardiac function assessed by echocardiography, and clinical parameters of HF were prospectively collected. The independent predictive association of TH with all investigated parameters of the HF severity were assessed. The patient's mean age was 74.4 years, 57.2% had arterial hypertension, 54.0% were consuming alcohol, and 42.3% were diabetics. Multivariate analysis revealed that total triiodothyronine (TT3) was an independent predictor of greater left ventricular ejection fraction (LVEF; β = 0.223, p = 0.008), less progressed left ventricular diastolic dysfunction (LVDD; β = - 0.271, p = 0.001) and lower N-terminal pro-brain natriuretic peptide (NT-proBNP; β = - 0.365, p < 0.001). None of the TH other than TT3 was associated with LVDD or NT-proBNP, whereas free triiodothyronine (β = - 0.197, p = 0.004), free thyroxine (β = - 0.223, p = 0.001) and total thyroxine (β = - 0.140, p = 0.041) were inversely associated with LVEF. The present study suggests that, among TH, serum TT3 level is most closely associated with echocardiographic, laboratory and clinical parameters of the severity of HF in men.

Non-thyroidal Illness Syndrome (NTIS) is no independent predictor for mortality in ICU patients

BACKGROUND

Low T3-(/T4-) syndrome, also known as non-thyroidal Illness Syndrome (NTIS) describes a decrease in free serum thyroid hormones without a concomitant increase in TSH, frequently observed in critically ill patients. However, whether NTIS is only a metabolic adaption to stress in critically ill or plays a crucial role as an independent risk factor for ICU mortality, remains unknown. Our study aimed to evaluate NTIS as an independent risk factor for increased ICU mortality.

METHODS

All patients admitted to the interdisciplinary intensive care unit (ICU) at the University Hospital of Leipzig between 2008 and 2014 were retrospectively analyzed for thyroidal function. Baseline data, information on additional thyroid function tests, disease progression, hospital and ICU length of stay (LOS) and patient outcome were retrospectively analyzed from the hospitals digital information system. For statistical evaluation, univariate analysis, matched pairs analysis and multivariate logistic regression were conducted.

RESULTS

One thousand, seven hundred ninety patients were enrolled in the study, of which 665 showed NTIS. Univariate analysis revealed a positive association of NTIS with ICU- and hospital-LOS, need for mechanical ventilation, incidence of sepsis, acute respiratory distress syndrome, acute liver failure and increased ICU mortality. Results of matched pair analysis confirmed these findings. In multivariate logistic regression, NTIS was associated with an increased ICU-LOS, increased duration of mechanical ventilation, acute kidney injury and liver failure, but showed no independent association with increased ICU-mortality.

CONCLUSION

Duration of mechanical ventilation as well as incidence of acute kidney injury, sepsis and acute liver failure were detected as independent predictors of mortality in patients with NTIS. NTIS itself was no independent predictor of increased ICU-mortality.

Analysis of clinical features and 7-year all-cause mortality in older male patients with non-thyroidal illness syndrome on general wards

PURPOSE

Older patients with non-thyroidal illness syndrome (NTIS) have a poor prognosis. However, there are few studies on the association of NTIS and mortality among older inpatients on general wards. In a 7-year retrospective observational study, we aimed to investigate the clinical features of NTIS and the association of NTIS and all-cause mortality in older inpatients.

METHODS

A total of 959 older male inpatients whose average age was 86.3 ± 8.1 years were enrolled and divided into the NTIS group and non-NTIS group. Cox models were performed to explore the association of thyroid hormone level and mortality.

RESULTS

Patients had more respiratory disease and chronic kidney disease in the NTIS than in the non-NTIS group, especially in primary nursing care, respiratory failure and haemodialysis patients; serum total protein, albumin, prealbumin, haemoglobin, uric acid and high-density lipoprotein cholesterol levels were lower, and urea nitrogen and fasting blood glucose levels were higher, in the NTIS than in the non-NTIS group. Patients in the NTIS group had a lower survival rate over 7 years follow-up (P < 0.01). A lower free T₃ level was associated with all-cause mortality with a HR of 1.50 (1.36, 1.66). Lower free T₄ level was associated with reduced all-cause mortality with a HR of 0.91 (0.88, 0.94) even after adjusting for confounding factors (P < 0.01).

CONCLUSIONS

Among older male inpatients, the survival rate was lower in the NTIS group. A reduced free T₃ level with low albumin and Hb levels was associated with all-cause mortality; moreover, a higher free T₄ in the normal range may be a strong predictor for long-term mortality risk in hospitalised older male patients.

Thyroid dysfunction during treatment with systemic antineoplastic therapy for childhood cancer: A systematic review

Thyroid dysfunction is known to occur following radiotherapy or chemotherapy for childhood cancer. Thyroid dysfunction during treatment for childhood cancer has, however, not been studied extensively, although thyroid hormones are of utmost importance during childhood. This information is needed to develop adequate screening protocols and may be of special importance with upcoming drugs, such as checkpoint inhibitors, which are highly associated with thyroid dysfunction in adults. In this systematic review we have evaluated the occurrence and risk factors for thyroid dysfunction in children during treatment with systemic antineoplastic drugs, up to three months after the end of therapy. Two review authors independently performed the study selection, data extraction and risk of bias assessment of included studies. After an extensive search (January 2021), in total six heterogeneous articles were included, reporting on 91 childhood cancer patients with a thyroid function test during treatment with systemic antineoplastic therapy for childhood cancer. All studies had risk of bias issues. Primary hypothyroidism was found in 18% of children treated with high dose interferon-α (HDI-α) and in 0-10% after tyrosine kinase inhibitors (TKIs). Transient euthyroid sick syndrome (ESS) was common (in 42-100%) during treatment with systematic multi-agent chemotherapy. Only one study addressed possible risk factors, showing different types of treatment to increase the risk. However, the exact prevalence, risk factors and clinical consequences of thyroid dysfunction remain unclear. Prospective high-quality studies including large study samples are needed to longitudinally assess the prevalence, risk factors and possible consequences of thyroid dysfunction during childhood cancer treatment.

Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization

Thyroid dysfunctions are among the most common endocrine disorders and accurate biochemical testing is needed to confirm or rule out a diagnosis. Notably, true hyperthyroidism and hypothyroidism in the setting of a normal thyroid-stimulating hormone level are highly unlikely, making the assessment of free thyroxine (FT4) inappropriate in most new cases. However, FT4 measurement is integral in both the diagnosis and management of relevant central dysfunctions (central hypothyroidism and central hyperthyroidism) as well as for monitoring therapy in hyperthyroid patients treated with anti-thyroid drugs or radioiodine. In such settings, accurate FT4 quantification is required. Global standardization will improve the comparability of the results across laboratories and allow the development of common clinical decision limits in evidence-based guidelines. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. However, technical and implementation challenges, including the establishment of different clinical decision limits for distinct patient groups, still remain. Accordingly, different assays and reference values cannot be interchanged. Two-way communication between the laboratory and clinical specialists is pivotal to properly select a reliable FT4 assay, establish reference intervals, investigate discordant results, and monitor the analytical and clinical performance of the method over time.

Thyroid hormones and platelet activation in COVID-19 patients

PURPOSE

To retrospectively describe the association between thyroid hormones (TH) and platelet activation, as represented by mean platelet volume (MPV), in a cohort of patients hospitalized for COVID-19 with no known thyroid disease, and to correlate these data with the severity of COVID-19 and the occurrence of death/ARDS (Acute Respiratory Distress Syndrome).

METHODS

103 patients with real-time polymerase chain reaction (RT-PCR) testing-confirmed COVID-19 and hospitalized were enrolled. Serum samples were collected from patients upon admission before starting any treatment. Chi-squared test was used to determine the association between euthyroid sick syndrome (ESS) and COVID-19 severity. Multivariate logistic regression was performed to evaluate the best independent predictors of COVID-19 deaths/ARDS.

RESULTS

39/103 (37.9%) of patients were found to have ESS, and this condition was an independent predictor for the severity of COVID-19 (p = 0.003). Lower TSH and lower FT3/FT4 ratio correlated with higher MPV (p = 0,001 and p = 0.010), with an opposite trend with respect to what has been documented in non-COVID patients. Increasing MPV and lower FT3 significantly increased the risk, in COVID-19 patients, of an adverse outcome of death/ARDS.

CONCLUSION

Increased platelet activation, as represented by increased MPV, has already been reported to correlate with COVID-19 severity, possibly as a consequence of cytokine release. We demonstrated, in a cohort of 103 patients with COVID-19, that MPV is inversely correlated to TH levels, in particular in the case of ESS, where downregulation of TH axis may occur in case of systemic cytokine inflammation and more severe outcomes (death/ARDS). That ESS itself may directly cause platelet activation, as demonstrated by higher MPV in these patients, is an interesting hypothesis which deserves further investigation.

Six-month multidisciplinary follow-up in multisystem inflammatory syndrome in children: An Italian single-center experience

Background

A severe multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 has been described after infection. A limited number of reports have analyzed the long-term complications related to pro-inflammatory status in MIS-C. We evaluated multiorgan impairment at the 6-month follow-up in MIS-C.

Methods

We enrolled 33 pediatric patients consecutively hospitalized for MIS-C and monitored for almost 6 months. The inter-relationship of patient's features and disease severity at admission with long term complications was studied by multivariate analysis.

Results

Endo-metabolic derangement, cardiac injury, respiratory, renal and gastrointestinal manifestations and neurological involvement are part of the initial presentation. The most abnormalities appear to resolve within the first few weeks, without significant long term dysfunction at the 6-months follow-up, except for endocrine (non-thyroidal illness syndrome in 12.1%, insulin resistance in 21.2%) and neurological system (27.3% cognitive or psychological, behavioral, adaptive difficulties). Endocrine and heart involvement at admission represent a significant factor on the long term sequelae; however no association between severity score and long-term outcome was noted.

Conclusions

The severity of initial clinical presentation may be associated to organ domain, however it is not related to long term sequelae. The prevalent organ restoration supports a predominant indirect immune-mediated injury triggered by a systemic inflammatory response; however a direct damage due to the viral entry could be not excluded. Eventhought our preliminary results seem to suggest that MIS-C is not a long-term risk condition for children health, a longer follow-up is mandatory to confirm this hypothesis.

Thyrotropin Levels in Patients with Coronavirus Disease 2019: Assessment during Hospitalization and in the Medium Term after Discharge

BACKGROUND

The objectives of this study were (1) to compare TSH levels between inpatients with critical versus non-critical coronavirus disease 19 (COVID-19), and (2) to describe the status of TSH levels three months after hospitalization.

METHODS

We collected data on adult patients hospitalized with COVID-19 at Amiens University Hospital. We compared TSH levels between inpatients with critical (intensive care unit admission and/or death) versus non-critical COVID-19. Thereafter, survivors were invited to return for a three-month post-discharge visit where thyroid function tests were performed, regardless of the availability of TSH measurement during hospitalization.

RESULTS

Among 448 inpatients with COVID-19, TSH assay data during hospitalization were available for 139 patients without prior thyroid disease. Patients with critical and non-critical forms of COVID-19 did not differ significantly with regard to the median (interquartile range) TSH level (0.96 (0.68-1.71) vs. 1.27 mIU/L (0.75-1.79), p = 0.40). Abnormal TSH level was encountered in 17 patients (12.2%); most of them had subclinical thyroid disease. TSH assay data at the three-month post-discharge visit were available for 151 patients without prior thyroid disease. Only seven of them (4.6%) had abnormal TSH levels. Median TSH level at the post-discharge visit was significantly higher than median TSH level during hospitalization.

CONCLUSIONS

Our findings suggest that COVID-19 is associated with a transient suppression of TSH in a minority of patients regardless of the clinical form. The higher TSH levels three months after COVID-19 might suggest recovery from non-thyroidal illness syndrome.

Investigation of the frequency of obstructive sleep apnoea syndrome in patients with subclinical hypothyroidism

Background

The aim of this study is to determine the frequency of obstructive sleep apnoea syndrome (OSAS) in a study group with the diagnosis of subclinical hypothyroidism and in a control group without the diagnosis of subclinical hypothyroidism. This study compares these two groups in terms of demographic characteristics, chronic diseases and especially polysomnographic data.

Methods

A total of 120 patients were included in this study. They consisted of 60 patients with newly diagnosed subclinical hypothyroidism and a control group of 60 patients with normal thyroid functions. Demographic, anthropometric, polysomnography data and Epworth Sleepiness Scale scores of the patients were recorded and compared.

Results

Any significant difference in the frequency and severity of OSAS was not detected. A significant difference was found in the oxygen desaturation index (ODI), the apnoea-hypopnoea index (AHI) in rapid eye movement sleep, the AHI in supine sleep position and the arousal index of the group experiencing subclinical hypothyroidism with OSAS.

Conclusion

This study showed that there was no increase in OSAS frequency in patients with subclinical hypothyroidism, but it demonstrated that the ODI and the arousal index were significantly increased in OSAS patients diagnosed with subclinical hypothyroidism. It is thought that the diagnosis and treatment of OSAS in these patients may be important in preventing cardiovascular complications.

Association between thyroid hormone levels and frailty in the community-dwelling oldest-old: a cross-sectional study

BACKGROUND

Changes in thyroid hormone levels are commonly recognized characters among the elderly, which were reported to potentially influence incident frailty. Therefore, we examined the cross-sectional associations of thyroid hormones (THs) with frailty as well as the five components characterizing frailty (fatigue, resistance, ambulation, number of illnesses, and loss of weight) among the oldest-old.

METHODS

Four hundred and eighty-seven community-dwelling oldest-old from a local community in Haidian District, Beijing, participated in our recruitment campaign between April 2019 and May 2020. The primary outcomes were a definitive diagnosis of frailty according to the FRAIL scale (Fatigue, Resistance, Ambulation, Illnesses, Loss of weight) and a positive score for each frailty subdomain. Demographic information (age, sex, marital status, and educational status), comorbidities, and details on the participants' lifestyles were recorded. Serum THs including free triiodothyronin (fT3), triiodothyronine (T3), free thyroxine (fT4), and thyroxine (T4) and thyroid stimulating hormone (TSH) levels were also measured at the beginning of our study. Logistic regressions were conducted to screen for potential risk factors for frailty and its subdomains.

RESULTS

Among the total 487 subjects at enrollment, 60 (12.23%) of them were diagnosed with subclinical hypothyroidism and 110 (22.59%) of the total population scored positive for frailty. Logistic regression analyses adjusted for all potential confounders, showed that frailty was significantly associated with the serum TSH concentration (odds ratio [OR]: 1.06), fT3 concentration (OR: 0.54), and subclinical hypothyroidism score (OR: 2.18). The association between fT4 and frailty was absent in our observational study. The fT3/fT4 ratio characterizing peripheral hormone conversion was also tested to be correlated with frailty.

CONCLUSION

Subclinical hypothyroidism, higher TSH level, lower fT3 level, and decreased fT3/fT4 ratio were all associated with frailty assessed by the FRAIL scale among the community-dwelling oldest-old, suggesting a relevant role of thyroid function in aging. Future longitudinal studies are warranted to determine the casual relationship between thyroid dysfunction and frailty in the oldest-old.

Serum albumin and FT3/FT4 ratio as additional co-morbidity parameters to predict mortality as a new approach: The Haseki Scoring Index (updated Charlson Comorbidity Index)

BACKGROUND

Charlson Comorbidity Index (CCI) is the common and valid method to predict mortality by classifying comorbidities such as cardiovascular, metabolic, renal, hepatic, pulmonary diseases, and malignancy. Novel risk factors are not included in the Charlson Comorbidity Index, such as thyroid hormone index (FT3/FT4 ratio) and serum albumin levels. In the present study, we aimed to assess whether the thyroid hormone index and albumin are useful clinical parameters in short and long-term mortality.

METHODS

In the retrospective cohort study with a 5 year follow up, the data of 1292 patients who were hospitalized between January 1st-June 30th of 2014 were examined. Three months mortality as short term and 5-year mortality as long term were evaluated.

RESULTS

Three months and 5 years mortality rates for 1064 patients were analyzed. We showed that hypoalbuminemia and thyroid hormone index had statistically significant effects on short and long-term mortality. According to ROC analysis it was demonstrated that the scoring system including biochemical parameters such as thyroid hormone index and serum albumin level was more significant for 3-month mortality. In addition, both scoring systems are equal in demonstrating long-term mortality.

CONCLUSION

Thyroid hormone index and albumin could improve the prognostic performance of the original Charlson Comorbidity Index in short term mortality. The combined score may offer improvements in comorbidity summarization over existing scores.

Criminal of Adverse Pregnant Outcomes: A Perspective From Thyroid Hormone Disturbance Caused by SARS-CoV-2

Nowadays, emerging evidence has shown adverse pregnancy outcomes, including preterm birth, preeclampsia, cesarean, and perinatal death, occurring in pregnant women after getting infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the underlying mechanisms remain elusive. Thyroid hormone disturbance has been unveiled consistently in various studies. As commonly known, thyroid hormone is vital for promoting pregnancy and optimal fetal growth and development. Even mild thyroid dysfunction can cause adverse pregnancy outcomes. We explored and summarized possible mechanisms of thyroid hormone abnormality in pregnant women after coronavirus disease 2019 (COVID-19) infection and made a scientific thypothesis that adverse pregnancy outcomes can be the result of thyroid hormone disorder during COVID-19. In which case, we accentuate the importance of thyroid hormone surveillance for COVID-19-infected pregnant women.

The Prognostic Role of Metabolic and Endocrine Parameters for the Clinical Severity of COVID-19

Objective

An outbreak of coronavirus disease-19 (COVID-19) began in December 2019 and spread globally, overwhelming the entire world. COVID-19 is a public health emergency of international concern. Due to its high morbidity and mortality rate, recognition of its risk and prognostic factors is important. We aimed to understand the relationship between metabolic and endocrine parameters and the prognosis of COVID-19.

Methods and Materials

This was a cross-sectional clinical study. A total of 70 patients with severe COVID-19 were enrolled. Laboratory results at the first admission time (including complete blood count, C-reactive protein, lactate dehydrogenase, blood glucose, calcium, phosphate, albumin, creatinine, magnesium, lipid profiles, liver enzymes, thyroid hormones, cortisol, and vitamin D) and outcome data were recorded. We divided patients into (1) intensive care unit- (ICU-) admitted and non-ICU-admitted and (2) survivors and nonsurvivors for estimation of severity and prognosis. We determined the risk factors associated with critical illness and poor prognosis.

Results

Patients with higher white blood cell (WBC) count and phosphate levels had significantly higher ICU admission rates. According to univariate analysis, serum levels of T3, phosphate, and WBC as well as the duration of hospitalization were associated with mortality. Multivariate analysis revealed that only WBC and duration of hospitalization were independent predictors for mortality rate in COVID-19 patients.

Conclusion

Our findings suggest that longer duration of hospitalization and higher WBC count are associated with poor outcomes in patients with COVID-19.

Thyroid Function and Risk of Anemia: A Multivariable-Adjusted and Mendelian Randomization Analysis in the UK Biobank

CONTEXT

Thyroid dysfunction is associated with higher anemia prevalence, although causality remains unclear.

OBJECTIVE

This study aimed to investigate the association between thyroid function and anemia.

METHODS

This cross-sectional and Mendelian randomization study included 445 482 European participants from the UK Biobank (mean age 56.77 years (SD 8.0); and 54.2% women). Self-reported clinical diagnosis of hypothyroidism was stated by 21 860 (4.9%); self-reported clinical diagnosis of hyperthyroidism by 3431 (0.8%). Anemia, defined as hemoglobin level of < 13 g/dL in men and < 12 g/dL in women, was present in 18 717 (4.2%) participants.

RESULTS

In cross-sectional logistic regression analyses, self-reported clinical diagnoses of hypo- and hyperthyroidism were associated with higher odds of anemia (OR 1.12; 95% CI, 1.05-1.19 and OR 1.09; 95% CI, 0.91-1.30), although with wide confidence intervals for hyperthyroidism. We did not observe an association of higher or lower genetically influenced thyrotropin (TSH) with anemia (vs middle tertile: OR for lowest tertile 0.98 [95% CI, 0.95-1.02]; highest tertile 1.02 [95% CI, 0.98-1.06]), nor of genetically influenced free thyroxine (fT4) with anemia. Individuals with genetic variants in the DIO3OS gene implicated in intracellular regulation of thyroid hormones had a higher anemia risk (OR 1.05; 95% CI, 1.02-1.10); no association was observed with variants in DIO1 or DIO2 genes.

CONCLUSION

While self-reported clinical diagnosis of hypothyroidism was associated with higher anemia risk, we did not find evidence supporting a causal association with variation of thyroid function within the euthyroid range. However, intracellular regulation of thyroid hormones might play a role in developing anemia.

Evaluation of the Thyroid Characteristics and Correlated Factors in Hospitalized Patients with Newly Diagnosed Type 2 Diabetes

BACKGROUND

Diabetes mellitus (DM) and thyroid dysfunction (TD) are two closely associated disorders. The objective of the present study was to investigate the thyroid status and the relationships between thyroid hormones, diabetic complications and metabolic parameters in hospitalized patients with newly diagnosed type 2 DM (T2DM).

METHODS

This was an observational cross-sectional study, conducting on 340 patients with newly diagnosed T2DM who were admitted to ward of endocrinology department and 120 matched individuals without diabetes. Anthropometric, clinical and biochemical data were collected. Spearman correlation coefficients were calculated to evaluate the correlations between thyroid hormones and other variables. Factors associated with diabetic nephropathy (DN) was analyzed with multivariate logistic regression.

RESULTS

Levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) were significantly lower in patients with T2DM as compared to control group without diabetes. The prevalence of TD was 21.2% in patients with diabetes, higher than that in controls (4.2%). The low T3 syndrome was the most frequent TD, shown in 14.7% of patients. The presence of diabetic complications DN, diabetic ketosis or ketoacidosis), metabolic and demographic factors, including age, glycemic control and insulin resistance were factors significantly associated with levels of thyroid hormones. FT3 level was inversely correlated with the level of urinary total protein (mg/24h) and the presence of DN. Multivariate analysis indicated low FT3 level as a strong independent risk factor (OR = 0.364, P = 0.001) for DN.

CONCLUSION

TD is not rarely seen in hospitalized patients with newly diagnosed T2DM. Diabetic complications and diabetes-related metabolic and demographic factors are related to thyroid hormone levels. Decreased FT3 is strongly correlated with the presence of DN.

High-TSH Subclinical Hypothyroidism Is Associated With Postoperative Mortality in Acute Type A Aortic Dissection

BACKGROUND

Subclinical hypothyroidism can negatively affect the cardiovascular system and increase the risk of mortality, especially for individuals with thyroid-stimulating hormone (TSH) levels above 10 mU/L. We investigated the relationship between high-TSH subclinical hypothyroidism and postoperative mortality in acute type A aortic dissection (ATAAD) patients.

METHOD

We enrolled 146 patients with ATAAD who underwent aortic surgery in Beijing Anzhen Hospital from July 2016 to November 2018. Thyroid hormone levels were obtained before surgery, and participants were divided into a ≥10mU/L TSH level group and a <10mU/L level group. Cox proportional hazard regression and subgroup analysis were conducted to examine the association of preoperative high-TSH subclinical hypothyroidism with postoperative mortality.

RESULT

Participants with preoperative high-TSH (≥10mU/L) subclinical hypothyroidism tended to have longer hospitalization stays after surgery [16.0 (IQR 11.0-21.0) days vs 12.5 (IQR 8.0-16.0) days, P=0.001]. During the first 30 days after operation, 15 of 146 patients died (10.3%); during a median of 3.16 (IQR 1.76-4.56) years of follow-up, 24 patients died (16.4%). Cox proportional hazard regression showed that preoperative high-TSH subclinical hypothyroidism was independently associated with 30-day mortality (HR=6.2, 95% CI, 1.7-22.0, P=0.005) and postoperative mortality after adjusting for age, sex, BMI, hypertension, ejection fraction, diabetes and history of PCI (HR=3.4, 95% CI, 1.4-8.0, P=0.005).

CONCLUSION

This study showed that preoperative high-TSH subclinical hypothyroidism was an independent predictor of postoperative mortality in ATAAD patients who underwent aortic surgery.

PECULIARITIES OF THYROID STATUS OF PRESCHOOL CHILDREN WITH ACUTE BRONCHITIS

OBJECTIVE

The aim: The aim of this study was to determine the characteristics of thyroid status (thyroid hormone, total and free fractions of triiodothyronine and thyroxine, reversible triiodothyronine, antibodies to thyroperoxidase) of preschool children with acute bronchitis.

PATIENTS AND METHODS

Materials and methods: We examined 135 preschool children (from 3 to 6 years old) with acute bronchitis (main group) and 28 apparently healthy subjects who were in the control group. It used clinical-anamnestic, laboratory and instrumental research methods. Evaluation of the course of acute bronchitis was carried out in the acute period of the disease. All results were statistically processed using the SPSS 26 package.

RESULTS

Results: In 33 % of patients with acute bronchitis there are subclinical abnormalities of thyroid hormones, which manifest themselves in the form of euthyroid sick syndrome. Namely, we found an increased concentration of reversible triiodothyronine in the serum, as well as a decrease in total triiodothyronine and its free fraction.

CONCLUSION

Conclusions: In patients with acute bronchitis in almost every third case there are functional shifts in hormonal status, which are manifested in the form of the first variant of the euthyroid sick syndrome.

Correlation between inflammatory parameters and pituitary-thyroid axis in patients with COVID-19

PURPOSE

Inflammation plays a critical role in the progression of COVID-19. Nonthyroidal illness syndrome (NTIS) has been increasingly recognized in affected patients. We aim to evaluate the correlation of thyroid hormones with markers of inflammation and association with disease outcome in hospitalized patients with COVID-19, and in two profiles of NTIS (low T3-normal/low FT4 vs. low T3-high FT4).

METHODS

consecutive patients admitted to a nonintensive care unit for COVID-19 were recruited. Infection was mild in 22%, moderate in 27.1% and severe in 50.8%; 7.41% died. T4, T3, FT4, FT3, and their ratios (T3/T4, FT3/FT4) were correlated with albumin, ferritin, fibrinogen, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), lactate dehydrogenase (LDH), and D-dimer.

RESULTS

Fifty five patients (50.9% men, median age 56 years) were included. Albumin correlated positively with T3 and hormones ratios, but negatively with FT4. T3, FT3, T3/T4, and FT3/FT4 correlated inversely with ferritin, fibrinogen, ESR, CRP, LDH, and D-dimer. FT4 showed direct correlation with fibrinogen and ESR. T3/T4 was lower in severe compared to mild/moderate disease [7.5 (4.5-15.5) vs. 9.2 (5.8-18.1); p = 0.04], and lower in patients who died than in those discharged [5 (4.53-5.6) vs. 8.1 (4.7-18.1); p = 0.03]. A low T3/high FT4 profile was associated with lower albumin, higher ferritin, and severity.

CONCLUSION

In this cohort, thyroid hormones correlated with inflammation and outcome. T3 and T3/T4 correlated inversely with inflammatory markers; a low T3/T4 ratio was associated with severity and poor prognosis. Patients with low T3 but high FT4 had higher ferritin, lower albumin, and more severe disease at presentation.

Impact of COVID-19 on the thyroid gland: an update

Coronavirus disease 2019 (COVID-19) is the pandemic of the new millennium. COVID-19 can cause both pulmonary and systemic inflammation, potentially determining multi-organ dysfunction. Data on the relationship between COVID-19 and thyroid have been emerging, and rapidly increasing since March 2020. The thyroid gland and the virus infection with its associated inflammatory-immune responses are known to be engaged in complex interplay. SARS-CoV-2 uses ACE2 combined with the transmembrane protease serine 2 (TMPRSS2) as the key molecular complex to infect the host cells. Interestingly, ACE2 and TMPRSS2 expression levels are high in the thyroid gland and more than in the lungs. Our literature search provided greater evidence that the thyroid gland and the entire hypothalamic-pituitary-thyroid (HPT) axis could be relevant targets of damage by SARS-CoV-2. Specifically, COVID-19-related thyroid disorders include thyrotoxicosis, hypothyroidism, as well as nonthyroidal illness syndrome. Moreover, we noticed that treatment plans for thyroid cancer are considerably changing in the direction of more teleconsultations and less diagnostic and therapeutical procedures. The current review includes findings that could be changed soon by new results on the topic, considering the rapidity of worldwide research on COVID-19.

Frequency of Euthyroid Sick Syndrome Before and After Renal Transplantation in Patients with End Stage Renal Disease and Its Association with Oxidative Stress

OBJECTIVE

In this study, we aimed to evaluate the frequency of euthyroid sick syndrome (ESS) before and after renal transplantation in patients with end-stage renal disease (ESRD), and its association with oxidative stress (OS) by evaluating thiol-disulfide levels.

METHODS

Free triiodothyronine (fT3), free thyroxine (fT4) thyroid stimulating hormone (TSH), and thiol and disulfide levels were recorded before and after renal transplantation in patients with ESRD. ESS was diagnosed in patients with unresponsive TSH to low fT3 and/or fT4 levels.

RESULTS

A total of 121 patients were included in the study. Of these, 69 (57%) were males and 52 (43%) were females. The mean age was 45 ± 12.61 years. ESS was detected in 39 (32%) of 121 patients. Of 39 patients, 24 (61%) had ESS before transplantation and 15 (39%) after transplantation. Sixteen of 24 (66.7%) patients with ESS before transplantation reached normal thyroid functions after transplantation. In post transplantation period, patients with ESS had significantly higher urea and creatinine (p = 0.025 and p = 0.009, respectively) compared to patients without ESS. Furthermore, thiol-disulfide levels of 20 patients with ESS at any time compared with 68 patients without ESS. It was found that native thiol and total thiol were significantly lower in patients with ESS (p = 0.025 and p = 0.044, respectively).

CONCLUSION

The present study is an initial evaluation of the OS and antioxidant status in the etiology of ESS in patients with renal transplantation. These patients have markedly low levels of antioxidant products, which support the possible role of OS in ESS.

Hormonal Defects Are Common during Puumala Hantavirus Infection and Associate with Disease Severity and Biomarkers of Altered Haemostasis

Central and peripheral hormone deficiencies have been documented during and after acute hantavirus infection. Thrombocytopenia and coagulation abnormalities are common findings in haemorrhagic fever with renal syndrome (HFRS). The associations between coagulation and hormonal abnormalities in HFRS have not been studied yet. Forty-two patients diagnosed with Puumala virus (PUUV) infection were examined during the acute phase and on a follow-up visit approximately one month later. Hormonal defects were common during acute PUUV infection. Overt (clinical) hypogonadism was identified in 80% of the men and approximately 20% of the patients had overt hypothyroidism. At the one-month follow-up visit, six patients had central hormone deficits. Acute peripheral hormone deficits associated with a more severe acute kidney injury (AKI), longer hospital stay and more severe thrombocytopenia. Half of the patients with bleeding symptoms had also peripheral hormonal deficiencies. Patients with free thyroxine levels below the reference range had higher D-dimer level than patients with normal thyroid function, but no thromboembolic events occurred. Acute phase hormonal abnormalities associate with severe disease and altered haemostasis in PUUV infection.

Effect of acute and chronic liver diseases on the thyroid function in children

BACKGROUND

Thyroid hormones modulate hepatic function through regulation of basal metabolic rate in addition; the liver metabolizes the thyroid hormones and regulates their endocrine effects.

OBJECTIVES

To assess thyroid functions in children with acute and chronic liver diseases.

METHODS

85 studied children were divided into 4 groups; group 1 (20 children) with acute hepatitis (AH), group 2 (20 children) chronic liver disease1 (CLD1; relatively preserved liver functions including Child-Pugh stage A), group 3 (20 children) chronic liver disease2 (CLD2; includes Child-Pugh stage B or C), group 4 (25 children) controls. All groups were subjected to detailed history, physical examination, Complete blood count, liver, renal function tests, viral markers, and thyroid functions (FT3, FT4, TSH).

RESULTS

Free T3 levels were lower in children with AH, CLD1 and CLD2. There was significant increase in TSH serum levels in CLD2.In acute hepatitis a negative correlation between serum free T4 and AST (r = -0.991), positive correlation between serum TSH and AST, VLDL, and cholesterol levels (r= 0.503, 0.533 and 0.498). A positive correlation between free T3 levels and prothrombin concentration (r= 0.991). Negative correlations between free T3 levels and PT, serum bilirubin and LDL serum levels in children with CLD2 (r= -0.992) (r= -0.902) and (r= -0.946) CONCLUSION: Acute and chronic liver diseases affect thyroid function in children and is correlated with the disease severity.

Low free-T3 serum levels and prognosis of COVID-19: systematic review and meta-analysis

OBJECTIVES

There is increasing interest regarding the relationship between serum levels of free triiodothyronine (fT3) and outcomes of COronaVIrus Disease-19 (COVID-19) patients. As several recent reports have described a worse prognosis in patients with low fT3 levels, we performed a meta-analysis to assess the prognostic role of fT3 serum levels in patients with COVID-19 as this information could be clinically relevant for the management of these patients.

METHODS

The methodology was registered in the International prospective register of systematic reviews (PROSPERO) database under the protocol number CRD42021260952. A systematic search was carried out on PubMed, Embase, Web of Science, and Scopus from May to June 2021 without time and language restrictions. The literature search strategy was based on the following keywords: (T3 OR fT3 OR triiodothyronine) AND (COVID-19) AND (prognosis OR survival).

RESULTS

The literature search identified 163 studies. Seven retrospective studies met the inclusion and exclusion criteria and were included in the meta-analysis. The included studies had a total of 1,183 patients. From the analysis of the included studies, lower fT3 serum levels were consistently observed in intensive care unit (ICU) than in non-ICU patients and in non-survivors than survivors, respectively.

CONCLUSIONS

Serum fT3 concentrations are significantly lower in patients with severe COVID-19 than in non-severely ill patients and predict all-cause mortality of patients with severe COVID-19. Accordingly, fT3 may become a simple tool for stratified management of patients with severe COVID-19.

An update on non-thyroidal illness syndrome

The non-thyroidal illness syndrome (NTIS) was first reported in the 1970s as a remarkable ensemble of changes in serum TH (TH) concentrations occurring in probably any severe illness. Ever since, NTIS has remained an intriguing phenomenon not only because of the robustness of the decrease in serum triiodothyronine (T3), but also by its clear correlation with morbidity and mortality. In recent years, it has become clear that (parenteral) feeding in patients with critical illness should be taken into account as a major determinant not only of NTIS but also of clinical outcome. Moreover, both experimental animal and clinical studies have shown that tissue TH concentrations during NTIS do not necessarily reflect serum low TH concentrations and may decrease, remain unaltered, or even increase according to the organ and type of illness studied. These differential changes now have a solid basis in molecular studies on organ-specific TH transporters, receptors and deiodinases. Finally, the role of inflammatory pathways in these non-systemic changes has begun to be clarified. A fascinating role for TH metabolism in innate immune cells, including neutrophils and monocytes/macrophages, was reported in recent years, but there is no evidence at this early stage that this may be a determinant of susceptibility to infections. Although endocrinologists have been tempted to correct NTIS by TH supplementation, there is at present insufficient evidence that this is beneficial. Thus, there is a clear need for adequately powered randomized clinical trials (RCT) with clinically relevant endpoints to fill this knowledge gap.

T3 as predictor of mortality in any cause non-critically ill patients

BACKGROUND

Low T3 syndrome refers to a set of thyroid hormone metabolism alterations present in the disease state. A correlation between low T3 and poor clinical outcomes in the intensive care unit is more established. Nonetheless, studies on non-critically ill patients are few and controversial.

OBJECTIVE

To evaluate the prevalence and predictive value of low T3 levels on 30-day and 6-month mortality in non-critically ill patients. Secondary outcomes evaluated the length of hospital stay, overall mortality, and hospital readmission.

DESIGN

Prospective cohort study.

METHODS

A total of 345 consecutive patients from the Internal Medicine ward of a tertiary hospital in southern Brazil were included and followed from October 2018 to April 2019 (6 months). Levels of total serum T3 were measured weekly, from admission to discharge, and correlated with 30-day and 6-month mortality.

RESULTS

Prevalence of low T3 was 36.6%. Low T3 levels were associated with higher 30-day hospital mortality (15.1% vs 4.1%, P < 0.001) and higher 6-month overall mortality (31.7% vs 13.2%, P < 0.001). Total serum T3 at admission was an independent predictor of 30-day hospital mortality.

CONCLUSION

Low T3 levels are a prevalent condition among non-critically ill patients, and this condition is associated with poor clinical outcomes in this population. Total serum T3 levels, alone or in association with other predictive scores, were demonstrated to be an easy and valuable tool for risk stratification and should be further employed in this setting.

PINK1 mediates the protective effects of thyroid hormone T3 in hyperoxia-induced lung injury

Hyperoxia can lead to respiratory failure and death. Our previous work demonstrates that oxidant and mitochondrial injury play a critical role in hyperoxia-induced acute lung injury (HALI). Recently, thyroid hormone has been demonstrated to promote mitochondrial survival in other models of lung injury, but its role in hyperoxia is unknown. Adult wild-type (WT) mice were pretreated with either nebulized triiodothyronine (T3, 40 μg/kg) for 1 or 3 days, or with propylthiouracil (PTU, 100 μg/kg), for 3 days. Following pretreatment, WT mice underwent 72 h of hyperoxia exposure. WT and PINK1-/- mice were pretreated with either nebulized T3 (40 μg/kg) for 3 days or no pretreatment before 72 h continuous hyperoxia exposure. Bronchoalveolar lavage (BAL), histological changes in cellular composition, and type I cytokine induction were assessed. Lung lysates for mitochondrial cellular bioenergetics markers were analyzed by Western blot. Hyperoxia caused a significant increase in BAL total cell counts and lung cellular infiltrates. Administration of PTU enhanced HALI, whereas T3 attenuated HALI, inflammation, and oxidants in WT mice. In addition, T3 pretreatment increased mitochondrial biogenesis/fusion/mitophagy and decreased ER stress and apoptosis. PINK1-/- mice were more susceptible to hyperoxia than WT mice. Notably, pretreatment with T3 did not attenuate HALI in PINK1-/- mice. In addition, T3 pretreatment increased mitochondrial anti-ROS potential, improved mitochondrial bioenergetics and mitophagy, and attenuated mitochondria-regulated apoptosis, all in a PINK1-dependent manner. Our results highlight a novel protective role for PINK1 in mediating the cytoprotective effects of thyroid hormone in HALI. Therefore, thyroid hormone may represent a potential therapy for ALI.

A prospective, observational clinical trial on the impact of COVID-19-related national lockdown on thyroid hormone in young males

Trying to manage the dramatic coronavirus disease 2019 (COVID-19) infection spread, many countries imposed national lockdown, radically changing the routinely life of humans worldwide. We hypothesized that both the pandemic per se and the consequent socio-psychological sequelae could constitute stressors for Italian population, potentially affecting the endocrine system. This study was designed to describe the effect of lockdown-related stress on the hypothalamic-pituitary-thyroid (HPT) axis in a cohort of young men. A prospective, observational clinical trial was carried out, including patients attending the male infertility outpatient clinic before and after the national lockdown for COVID-19 pandemic. The study provided a baseline visit performed before and a follow-up visit after the lockdown in 2020. During the follow-up visit, hormonal measurements, lifestyle habits and work management were recorded. Thirty-one male subjects were enrolled (mean age: 31.6 ± 6.0 years). TSH significantly decreased after lockdown (p = 0.015), whereas no significant changes were observed in the testosterone, luteinising hormone, follicle-stimulating hormone, estradiol and prolactin serum levels. No patient showed TSH serum levels above or below reference ranges, neither before nor after lockdown. Interestingly, TSH variation after lockdown was dependent on the working habit change during lockdown (p = 0.042). We described for the first time a TSH reduction after a stressful event in a prospective way, evaluating the HPT axis in the same population, before and after the national lockdown. This result reinforces the possible interconnection between psychological consequences of a stressful event and the endocrine regulation.

Aging and the hypothalamic-pituitary-thyroid axis

The world's population is increasingly aging, this noted particularly in the Western world where there are ever greater numbers of centenarians and those over 85 years. Given the immense importance of the thyroid gland for optimal health and the fact that morphological and functional changes in the hypothalamic-pituitary-thyroid (HPT) axis take place as a natural adaptation to the aging process, a clear distinction must be made in older individuals between these and the onset of disease. However, this is problematic since, frequently, subtle differences exist between them, making diagnosis a challenging task, especially as concerns subclinical disease. The newly emerging interdisciplinary field of geroscience offers the prospect of being used as a platform to investigate the effect of disrupted HPT function on functional capacity and cognitive ability among the aged, as well as the risk or onset of age-associated diseases, thus enhancing healthspan and lifespan. Because optimal functioning of the thyroid gland is a prerequisite for longevity as well as for mental and physical wellbeing, this review summarizes the recent scientific data regarding HPT and aging while discussing alternative and personalized treatment approaches to maintaining a healthy thyroid as a means to ensuring a long, active, and healthy life.

Sick Euthyroid Syndrome on Presentation of Patients With COVID-19: A Potential Marker for Disease Severity

OBJECTIVE

Precise risk stratification and triage of coronavirus disease 2019 (COVID-19) patients are essential in the setting of an overwhelming pandemic burden. Clinical observation has shown a somewhat high prevalence of sick euthyroid syndrome among patients with COVID-19. This study aimed to evaluate the predictive value of free triiodothyronine (FT3) at the clinical presentation of COVID-19 for disease severity and death.

METHODS

This retrospective cohort study was based on electronic medical records. The study was conducted at Sheba Medical Centre, a tertiary hospital where several acute and chronic wards have been dedicated to the treatment of patients with COVID-19. The primary outcome measure was death during hospitalization; secondary outcomes included hospitalization in intensive care, mechanical ventilation, and length of hospitalization.

RESULTS

Of a total of 577 polymerase chain reaction-positive patients with COVID-19 hospitalized between February 27 and July 30, 2020, 90 had at least 1 measurement of thyroid-stimulating hormone, free thyroxine, and FT3 within 3 days of presentation. After applying strict exclusion criteria, 54 patients were included in the study. Patients in the lowest tertile of FT3 had significantly higher rates of mortality (40%, 5.9%, and 5.9%, P = .008), mechanical ventilation (45%, 29.4%, and 0.0%; P = .007) and intensive care unit admission (55%, 29.4%, and 5.9%, P = .006). In multivariate analyses adjusted for age, Charlson comorbidity index, creatinine, albumin, and white blood cell count. FT3 remained a significant independent predictor of death.

CONCLUSION

FT3 levels can serve as a prognostic tool for disease severity in the early presentation of COVID-19.

Serum Total Thyroxine Evaluation in Critically Ill Feline Patients

This retrospective case control study compared serum total thyroxine (tT4) concentrations in hospitalized critical cats (CCs) and non-hospitalized cats with non-thyroidal chronic diseases (chronic group, CG) and evaluated the relationship between the serum tT4 concentration of CCs and systemic inflammation (systemic inflammatory response syndrome (SIRS)), disease severity (Acute Patient Physiologic and Laboratory Evaluation (APPLEfast)), and prognosis. Cats with previously suspected or diagnosed thyroid disease were excluded. Serum tT4 was evaluated in surplus serum samples at the time of admission for CCs and CGs. The APPLEfast score of the CC group was calculated at admission. The systemic inflammatory response syndrome (SIRS) in CCs was determined using proposed criteria. Cats were divided into survivors and non-survivors according to the discharge outcome. Forty-nine cats were retrospectively included. Twenty-seven cats died during hospitalization. The CG group was composed of 37 cats. The CC group showed a significantly lower tT4 compared to the CG group (1.3 ± 0.7 vs. 2 ± 0.9; p < 0.0001). Among SIRS, APPLEfast, and tT4, only tT4 was associated with mortality (p = 0.04). The tT4 cut-off point for mortality was 1.65 μg/dL (sensitivity 81%, specificity 57%, odds ratio (OR) 5.6). Twenty-five cats (51%) had SIRS that was not associated with tT4. Non-thyroidal illness syndrome can occur in critically ill cats and the evaluation of tT4 in hospitalized cats could add prognostic information.

Thyroid Hormones Interaction With Immune Response, Inflammation and Non-thyroidal Illness Syndrome

The interdependence between thyroid hormones (THs), namely, thyroxine and triiodothyronine, and immune system is nowadays well-recognized, although not yet fully explored. Synthesis, conversion to a bioactive form, and release of THs in the circulation are events tightly supervised by the hypothalamic-pituitary-thyroid (HPT) axis. Newly synthesized THs induce leukocyte proliferation, migration, release of cytokines, and antibody production, triggering an immune response against either sterile or microbial insults. However, chronic patho-physiological alterations of the immune system, such as infection and inflammation, affect HPT axis and, as a direct consequence, THs mechanism of action. Herein, we revise the bidirectional crosstalk between THs and immune cells, required for the proper immune system feedback response among diverse circumstances. Available circulating THs do traffic in two distinct ways depending on the metabolic condition. Mechanistically, internalized THs form a stable complex with their specific receptors, which, upon direct or indirect binding to DNA, triggers a genomic response by activating transcriptional factors, such as those belonging to the Wnt/β-catenin pathway. Alternatively, THs engage integrin αvβ3 receptor on cell membrane and trigger a non-genomic response, which can also signal to the nucleus. In addition, we highlight THs-dependent inflammasome complex modulation and describe new crucial pathways involved in microRNA regulation by THs, in physiological and patho-physiological conditions, which modify the HPT axis and THs performances. Finally, we focus on the non-thyroidal illness syndrome in which the HPT axis is altered and, in turn, affects circulating levels of active THs as reported in viral infections, particularly in immunocompromised patients infected with human immunodeficiency virus.

Interpretation of the endocrinology of hospital inpatients

Blood tests to assess the endocrine system are commonly performed in patients admitted to hospital. This may be because an endocrinopathy is thought to be aetiological in the presenting disease or suspected as an incidental occurrence by the clinician. Many patients, in addition to the pathology leading to admission, frequently have one or more comorbidities, a change in nutritional status and polypharmacy. Added to this, presentation with acute illness is a major life stress. All of these are likely to impact on one or more endocrine axes, although often only transiently. Endocrine evaluation in the vast majority of cases can be safely deferred to the outpatient setting. This article considers the most common endocrine anomalies discovered in hospital, the confounders, and provides guidance on how to investigate these further.

Changes in thyroid function in patients with liver failure and their clinical significance: A clinical study of non-thyroidal illness syndrome in patients with liver failure

BACKGROUND

Non-thyroidal illness syndrome (NTIS) develops in a large proportion of critically ill patients and is associated with high risk for death. We aimed to investigate the correlation between NTIS and liver failure, and the short-term mortality of patients with these conditions.

METHODS

The clinical data of 87 patients with liver failure were collected retrospectively, 73 of them were randomly selected for an observational study and to establish prognostic models, and 14 for model validation. Another 73 sex- and age-matched patients with mild chronic hepatitis were randomly selected as a control group. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured. The clinical characteristics of patients with liver failure and NTIS were analyzed. The follow-up of patients lasted for 3 months. Additionally, the values for predicting short-term mortality of model for end-stage liver disease (MELD), Child-Turcotte-Pugh (CTP), chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores, FT3-MELD model, and FT3 were evaluated.

RESULTS

The observation group had significantly lower FT3 (2.79 ± 0.71 vs. 4.43 ± 0.75 pmol/L, P < 0.001) and TSH [0.618 (0.186-1.185) vs. 1.800 (1.570-2.590) mIU/L, P < 0.001], and higher FT4 (19.51 ± 6.26 vs. 14.47 ± 2.19 pmol/L, P <0.001) than the control group. NTIS was diagnosed in 49 of the patients with liver failure (67.12%). In the observation group, patients with NTIS had a higher mortality rate than those without (63.27% vs. 25.00%, P = 0.002). Across the whole cohort, the 3-month mortality was 50.68%. The international normalized ratios (INR) were 2.40 ± 1.41 in survivors and 3.53 ± 1.81 in deaths (P = 0.004), the creatinine (Cr) concentrations were 73.27 ± 36.94 µmol/L and 117.08 ± 87.98 µmol/L (P = 0.008), the FT3 concentrations were 3.13 ± 0.59 pmol/L and 2.47 ± 0.68 pmol/L (P < 0.001), the MELD scores were 22.19 ± 6.64 and 29.57 ± 7.99 (P < 0.001), the CTP scores were 10.67 ± 1.53 and 11.78 ± 1.25 (P = 0.001), and the CLIF-SOFA scores were 8.42 ± 1.68 and 10.16 ± 2.03 (P < 0.001), respectively. FT3 was negatively correlated with MELD score (r = -0.430, P < 0.001). An FT3-MELD model was established by subjecting FT3 concentration and MELD score to logistic regression analysis using the following formula: Logit(P) = -1.337 × FT3+0.114 × MELD+0.880. The area under the receiver operating characteristic (ROC) curve was 0.827 and the optimal cut-off value was 0.4523. The corresponding sensitivity and specificity were 67.6% and 91.7%. The areas under the ROC curve for FT3 concentration, MELD score, CTP score, and CLIF-SOFA score were 0.809, 0.779, 0.699, and 0.737, respectively.

CONCLUSIONS

Patients with liver failure often develop NTIS. FT3-MELD score perform better than CTP and CLIF-SOFA scores in predicting mortality in patients with liver failure. Thus, the FT3-MELD model could be of great value for the evaluation of the short-term mortality of such patients.

Response of preterm infants with transient hypothyroxinaemia of prematurity to the thyrotropin-releasing hormone stimulation test is characterized by a delayed decrease in thyroid-stimulating hormone after the peak

OBJECTIVES

We evaluated the response to the thyrotropin-releasing hormone (TRH) stimulation test in very low-birth weight (VLBW) infants to elucidate the aetiology of transient hypothyroxinaemia of prematurity (THOP).

DESIGN AND METHODS

We performed TRH stimulation tests on 43 VLBW infants. Subjects were divided into two groups; a THOP group (N = 11; basal TSH < 15 mU/L and basal FT4 ≤ 0.8 ng/dL) and a non-THOP group (N = 32; basal TSH < 15 mU/L and basal FT4 > 0.8 ng/dL). Basal FT4 and FT3 were measured before, and TSH (0, 30, 60, 90, 120 and 180 minutes) was measured after, the administration of TRH (7 µg/kg). We calculated the ratio of TSH 180 minutes to THS 0 minute as the primary outcome. We also collected data on T3 and rT3 in this study.

RESULTS

In both groups, TSH 30 minutes values were the highest. However, the ratios of TSH 180 minutes to THS 0 minutes in the non-THOP group and the THOP group were (median [IQR]) 1.3 [1.0-1.7] and 3.0 [1.5-5.3] (P < .01). No significant differences were observed in T3 (1.0 [0.8-1.3] and 0.7 [0.4-0.7] ng/mL, P = .06). However, in the THOP group, rT3 was significantly lower than that of the non-THOP group (168.0 [148.1-197.0] and 92.9 [74.7-101.6] pg/mL, P < .01).

CONCLUSIONS

The delayed decrease in the TSH concentration after the peak for the TRH tests and decreased levels of rT3 suggest that the main aetiology for THOP is suppression at the level of the hypothalamus, but not inactivation of peripheral thyroid hormone metabolism.

Moderate SIRT1 overexpression protects against brown adipose tissue inflammation

OBJECTIVE

Metainflammation is a chronic low-grade inflammatory state induced by obesity and associated comorbidities, including peripheral insulin resistance. Brown adipose tissue (BAT), a therapeutic target against obesity, is an insulin target tissue sensitive to inflammation. Therefore, it is necessary to find strategies to protect BAT against the effects of inflammation in energy balance. In this study, we explored the impact of moderate sirtuin 1 (SIRT1) overexpression on insulin sensitivity and β-adrenergic responses in BAT and brown adipocytes (BA) under pro-inflammatory conditions.

METHODS

The effect of inflammation on BAT functionality was studied in obese db/db mice and lean wild-type (WT) mice or mice with moderate overexpression of SIRT1 (SIRT1^Tg+) injected with a low dose of bacterial lipopolysaccharide (LPS) to mimic endotoxemia. We also conducted studies on differentiated BA (BA-WT and BA-SIRT1^Tg+) exposed to a macrophage-derived pro-inflammatory conditioned medium (CM) to evaluate the protection of SIRT1 overexpression in insulin signaling and glucose uptake, mitochondrial respiration, fatty acid oxidation (FAO), and norepinephrine (NE)-mediated-modulation of uncoupling protein-1 (UCP-1) expression.

RESULTS

BAT from the db/db mice was susceptible to metabolic inflammation manifested by the activation of pro-inflammatory signaling cascades, increased pro-inflammatory gene expression, tissue-specific insulin resistance, and reduced UCP-1 expression. Impairment of insulin and noradrenergic responses were also found in the lean WT mice upon LPS injection. In contrast, BAT from the mice with moderate overexpression of SIRT1 (SIRT1^Tg+) was protected against LPS-induced activation of pro-inflammatory signaling, insulin resistance, and defective thermogenic-related responses upon cold exposure. Importantly, the decline in triiodothyronine (T₃) levels in the circulation and intra-BAT after exposure of the WT mice to LPS and cold was markedly attenuated in the SIRT1^Tg+ mice. In vitro BA experiments in the two genotypes revealed that upon differentiation with a T₃-enriched medium and subsequent exposure to a macrophage-derived pro-inflammatory CM, only BA-SIRT1^Tg+ fully recovered insulin and noradrenergic responses.

CONCLUSIONS

This study has ascertained the benefit of the moderate overexpression of SIRT1 to confer protection against defective insulin and β-adrenergic responses caused by BAT inflammation. Our results have potential therapeutic value in combinatorial therapies for BAT-specific thyromimetics and SIRT1 activators to combat metainflammation in this tissue.

Serum thyroxine and thyrotropin concentrations decrease with severity of nonthyroidal illness in cats and predict 30-day survival outcome

Background

In cats, nonthyroidal illness affects serum thyroid hormone concentrations. Serum thyroxine (T₄) and triiodothyronine (T₃) concentrations commonly decrease, whereas free T₄ (fT₄) concentrations vary unpredictably. Limited information exists regarding effects on serum thyrotropin (thyroid‐stimulating hormone [TSH]) concentrations in cats with nonthyroidal illness syndrome (NTIS).

Objectives

To characterize alterations in thyroid function that develop in cats with NTIS and to correlate these alterations with severity and outcome of the nonthyroidal illness.

Animals

Two hundred and twenty‐two cats with NTIS and 380 clinically normal cats of similar age and sex.

Methods

Prospective, cross‐sectional study. All cats had serum T₄, T₃, free T₄, and TSH concentrations measured. Cats were grouped based on illness severity and 30‐day survival.

Results

Cats with NTIS had lower serum T₄ and T₃ concentrations than did normal cats (P < .001). Serum fT₄ and TSH concentrations did not differ between groups. Serum T₄, T₃, and fT₄ concentrations progressively decreased with increasing disease severity (P < .001). The 56 cats that died had lower T₄, T₃, and TSH concentrations than did the 166 survivors, with no difference in fT₄ concentration. Multivariable logistic regression modeling indicated that serum T₄ and TSH concentrations both predicted survival (P < .02).

Conclusions and Clinical Importance

Cats with NTIS commonly develop low serum T₄, T₃, and TSH concentrations, the prevalence and extent of which increases with disease severity. Clinicians should consider evaluating thyroid function in cats with severe NTIS, because doing so could help determine probability of successful treatment responses before investing considerable time, effort, and finances in addressing the underlying disease.

T3 Critically Affects the Mhrt/Brg1 Axis to Regulate the Cardiac MHC Switch: Role of an Epigenetic Cross-Talk

The LncRNA my-heart (Mhrt) and the chromatin remodeler Brg1 inhibit each other to respectively prevent or favor the maladaptive α-myosin-heavy-chain (Myh6) to β-myosin-heavy-chain (Myh7) switch, so their balance crucially guides the outcome of cardiac remodeling under stress conditions. Even though triiodothyronine (T3) has long been recognized as a critical regulator of the cardiac Myh isoform composition, its role as a modulator of the Mhrt/Brg1 axis is still unexplored. Here the effect of T3 on the Mhrt/Brg1 regulatory circuit has been analyzed in relation with chromatin remodeling and previously identified T3-dependent miRNAs. The expression levels of Mhrt, Brg1 and Myh6/Myh7 have been assessed in rat models of hyperthyroidism or acute myocardial ischemia/reperfusion (IR) treated with T3 replacement therapy. To gain mechanistic insights, in silico analyses and site-directed mutagenesis have been adopted in combination with gene reporter assays and loss or gain of function strategies in cultured cardiomyocytes. Our results indicate a pivotal role of Mhrt over-expression in the T3-dependent regulation of Myh switch. Mechanistically, T3 activates the Mhrt promoter at two putative thyroid hormone responsive elements (TRE) located in a crucial region that is necessary for both Mhrt activation and Brg1-dependent Mhrt repression. This newly identified T3 mode of action requires DNA chromatinization and is critically involved in mitigating the repressive function of the Brg1 protein on Mhrt promoter. In addition, T3 is also able to prevent the Brg1 over-expression observed in the post-IR setting through a pathway that might entail the T3-mediated up-regulation of miR-208a. Taken together, our data evidence a novel T3-responsive network of cross-talking epigenetic factors that dictates the cardiac Myh composition and could be of great translational relevance.