The influence of 3,3',5-triiodo-L-thyronine on human haematopoiesis

Association between radioactive iodine uptake and neutropenia in untreated Graves' disease

Objective

Neutropenia is a complication of Graves' disease (GD), but there is currently no means by which to predict its occurrence. This study aimed to investigate the risk factors for the development of neutropenia in untreated GD.

Methods

This was a retrospective cohort study. Between January 1, 2010, and July 31, 2020, 1000 patients with new-onset or relapsing GD without treatment were enrolled in the study and divided into two groups: neutropenia group (neutrophil count < 2 × 109/L) and non-neutropenia group (neutrophil count ≥ 2 × 109/L). Clinical characteristics of subjects were compared between the two groups, and logistic regression analysis was applied to determine risk factors for neutropenia. To further explore the correlation of radioactive iodine uptake (RAIU) with neutropenia, subjects were first classified according to quartile of 3 h RAIU and 24 h RAIU prior to logistic regression analysis.

Results

Of all patients recruited, 293 (29.6%) were diagnosed with neutropenia. Compared with non-neutropenic patients, those with neutropenia had a higher level of free thyroxine (FT4) (56.64 ± 31.80 vs 47.64 ± 39.64, P = 0.001), 3 h RAIU (55.64 ± 17.04 vs 49.80 ± 17.21, P < 0.001) and 24 h RAIU (67.38 ± 12.54 vs 64.38 ± 13.58, P < 0.001). Univariate logistic regression analysis revealed that FT4, 3 h RAIU, 24 h RAIU, creatinine, and low-density lipoprotein were risk factors for development of neutropenia in GD. After adjusting for confounding factors of age, BMI, and sex, we determined that 3 h RAIU and 24 h RAIU (Model 1: OR = 1.021, 95% CI: 1.008-1.033, P = 0.001; Model 2: OR = 1.023, 95% CI: 1.007-1.039, P = 0.004), but not FT4, were associated with the development of neutropenia.

Conclusions

RAIU is associated with neutropenia in patients with untreated GD.

Thyroid hormones inhibit apoptosis of macrophage induced by oxidized low-density lipoprotein

Increasing evidence suggests that hypothyroidism aggravates atherosclerosis. Macrophage apoptosis plays a significant role in the development of atherosclerotic plaque. We aimed to explore the effect of thyroid hormones on macrophage apoptosis induced by oxidized low-density lipoprotein (oxLDL). Peripheral blood samples from 20 patients (normal group, hypothyroidism group, coronary artery disease [CAD] group, hypothyroidism + CAD group) were collected to perform messenger RNA microarray analysis. Bioinformatics analysis identified apoptosis and mitogen-activated protein kinase (MAPK) signaling as differentially expressed pathways between CAD and hypothyroidism + CAD group. In vitro, thyroid hormones concentration-dependently promoted cell survival and inhibited apoptosis in oxLDL-treated RAW264.7 macrophages, along with elevated extracellular signal-regulated kinases 1 and 2 (Erk1/2) phosphorylation. The STRING database showed an interaction of thyroid hormone receptor alpha1 (TRα1) and MAPK pathway. TRα1 knockdown increased cell apoptosis and decreased Erk1/2 phosphorylation. Erk1/2 inhibitor aggravated macrophage apoptosis. Moreover, thyroid hormones inhibited oxidative stress in oxLDL-treated macrophages. The study indicates that thyroid hormones concentration-dependently attenuate oxLDL-induced macrophage apoptosis through activating TRα1-Erk1/2 pathway and inhibiting oxidative stress, which implies a potential mechanism of hypothyroid-accelerated atherosclerosis.

Can neutrophil/lymphocyte ratio be used as an indicator of inflammation in patients with hyperthyroidism?

Background

In our study, we aimed to evaluate changes in the neutrophil and lymphocyte series and investigate whether the neutrophil/lymphocyte ratio (NLR) is indicative of inflammations in patients with hyperthyroidism.

Methods

A total of 161 patients were enrolled, 121 of which had hyperthyroidism (71 Graves' Disease (GD) and 50 non-Graves hyperthyroidism (NGH) patients) and 40 of which were control group members. Retrospectively, patients' neutrophil and lymphocyte counts were taken, and the NLR was calculated.

Results

While the number of neutrophils was significantly lower in the GD group (p = 0.003), there was no significant difference between the NGH and the control group. In the GD group, NLR values were significantly lower than the other two groups (median 1.39 for GD, median 1.84 for NGH and median 1.83 for the control group, p < 0.001). Only three patients in the GD group had neutropenia. There was also a significant negative correlation between free T3 and neutrophil count and NLR in hyperthyroid patients (r = -0.28, p = 0.001 and r = -0.34, p < 0.001, respectively).

Conclusions

In our study, we found that NLR did not in crease in hyperthyroid patients and that this ratio decreased due to the decrease in neutrophil levels in GD. We thus concluded that NLR is not a suitable indicator of hyperthyroidism.

A review of select minerals influencing the haematopoietic process

Micronutrients are indispensable for adequate metabolism, such as biochemical function and cell production. The production of blood cells is named haematopoiesis and this process is highly consuming due to the rapid turnover of the haematopoietic system and consequent demand for nutrients. It is well established that micronutrients are relevant to blood cell production, although some of the mechanisms of how micronutrients modulate haematopoiesis remain unknown. The aim of the present review is to summarise the effect of Fe, Mn, Ca, Mg, Na, K, Co, iodine, P, Se, Cu, Li and Zn on haematopoiesis. This review deals specifically with the physiological requirements of selected micronutrients to haematopoiesis, showing various studies related to the physiological requirements, deficiency or excess of these minerals on haematopoiesis. The literature selected includes studies in animal models and human subjects. In circumstances where these minerals have not been studied for a given condition, no information was used. All the selected minerals have an important role in haematopoiesis by influencing the quality and quantity of blood cell production. In addition, it is highly recommended that the established nutrition recommendations for these minerals be followed, because cases of excess or deficient mineral intake can affect the haematopoiesis process.

Thyroid hormone regulates hematopoiesis via the TR-KLF9 axis

Congenital hypothyroidism (CH) is one of the most prevalent endocrine diseases, for which the underlying mechanisms remain unknown; it is often accompanied by anemia and immunodeficiency in patients. Here, we created a severe CH model together with anemia and T lymphopenia to mimic the clinical features of hypothyroid patients by ethylnitrosourea (ENU) mutagenesis in Bama miniature pigs. A novel recessive c.1226A>G transition of the dual oxidase 2 (DUOX2) gene was identified as the causative mutation. This mutation hindered the production of hydrogen peroxide (H₂O₂) and thus contributed to thyroid hormone (TH) synthesis failure. Transcriptome sequencing analysis of the thymuses showed that Krüppel-like factor 9 (KLF9) was predominantly downregulated in hypothyroid mutants. KLF9 was verified to be directly regulated by TH in a TH receptor (TR)-dependent manner both in vivo and in vitro. Furthermore, knockdown of klf9 in zebrafish embryos impaired hematopoietic development including erythroid maturation and T lymphopoiesis. Our findings suggest that the TR-KLF9 axis is responsible for the hematopoietic dysfunction and might be exploited for the development of novel therapeutic interventions for thyroid diseases.

The Impact of Growth Hormone Therapy on the Apoptosis Assessment in CD34+ Hematopoietic Cells from Children with Growth Hormone Deficiency

Growth hormone (GH) modulates hematopoietic cell homeostasis and is associated with apoptosis control, but with limited mechanistic insights. Aim of the study was to determine whether GH therapeutic supplementation (GH-TS) could affect apoptosis of CD34+ cells enriched in hematopoietic progenitor cells of GH deficient (GHD) children. CD34+ cells from peripheral blood of 40 GHD children were collected before and in 3rd and 6th month of GH-TS and compared to 60 controls adjusted for bone age, sex, and pubertal development. Next, apoptosis assessment via different molecular techniques was performed. Finally, to comprehensively characterize apoptosis process, global gene expression profile was determined using genome-wide RNA microarray technology. Results showed that GH-TS significantly reduced spontaneous apoptosis in CD34+ cells (p < 0.01) and results obtained using different methods to detect early and late apoptosis in analyzed cells population were consistent. GH-TS was also associated with significant downregulation of several members of TNF-alpha superfamily and other genes associated with apoptosis and stress response. Moreover, the significant overexpression of cyto-protective and cell cycle-associated genes was detected. These findings suggest that recombinant human GH has a direct anti-apoptotic activity in hematopoietic CD34+ cells derived from GHD subjects in course of GH-TS.

The teleost head kidney: Integrating thyroid and immune signalling

The head kidney, analogous to the mammalian adrenal gland, is an organ unique for teleost fish. It comprises cytokine-producing lymphoid cells from the immune system and endocrine cells secreting cortisol, catecholamines, and thyroid hormones. The intimate organization of the immune system and endocrine system in one single organ makes bidirectional signalling between these possible. In this review we explore putative interactions between the thyroid and immune system in the head kidney. We give a short overview of the thyroid system, and consider the evidence for the presence of thyroid follicles in the head kidney as a normal, healthy trait in fishes. From mammalian studies we gather data on the effects of three important pro-inflammatory cytokines (TNFα, IL-1β, IL-6) on the thyroid system. A general picture that emerges is that pro-inflammatory cytokines inhibit the activity of the thyroid system at different targets. Extrapolating from these studies, we suggest that the interaction of the thyroid system by paracrine actions of cytokines in the head kidney is involved in fine-tuning the availability and redistribution of energy substrates during acclimation processes such as an immune response or stress response.

High Frequency of Thyroid Disorders in Patients Presenting With Neutropenia to an Outpatient Hematology Clinic STROBE-Compliant Article

Granulopoiesis abnormalities have been described in association with thyroid disorders (TD). However, data regarding systematic evaluation of adult neutropenia and concurrent or prior TD are scarce. To investigate the frequency of TD among patients presenting with neutropenia, and the immunophenotypic and immunologic profile of neutropenic patients with concomitant thyroidopathy. Two hundred eighteen consecutive neutropenic patients were prospectively evaluated in our outpatient Hematology Clinic, with a detailed laboratory screen, including thyroid function tests, antineutrophil antibodies, blood lymphocytes immunophenotyping, and detection of T-cell clonality by PCR. Among 218 patients with neutropenia, 95 (43.6%) had TD, 65 chronic immunologic neutropenia, 20 clonal proliferation of T-large granular lymphocytes (T-LGL), 5 autoimmune disorders, and 33 other diagnoses. TD-patients had an increased frequency of recurrent infections compared with other patients (P = 0.045). The following correlations were found: negative correlation between FT3 and absolute neutrophil count (ANC) (r² = -0.274, P = 0.007), negative correlation between TPO-Abs/TG-Abs and C4 (r² = -0.16, P = 0.045; r² = -0.266, P = 0.001), and CD4⁺ counts were inversely correlated to T4 and positively to TSH (r² = -0.274, P = 0.024; r² = 0.16, P = 0.045). In addition, TD-patients had significantly higher percentages of CD4⁺ lymphocytes (P = 0.003). Among TD-patients, 23.4% had Hashimoto thyroiditis (HT), 4.1%, Graves disease (GD), 8.2% nontoxic multinodular goiter (NTMG), 5% subclinical hypothyroidism, and 2.8% had undergone total thyroidectomy associated with nodules (TTM). Thirteen TD-patients displayed T-LGL. Patients with autoimmune thyroidopathy had an increased frequency of concomitant autoimmune manifestations (P = 0.03). Significant differences between the different thyroidopathies included: HT-patients had higher percentages of B-lymphocytes, while the opposite was evident for the TTM-subgroup (P = 0.009, 0.02); GD-patients showed an increase of the proportion of NK cells and a decrease in the percentage of TCRγδ+ lymphocytes (P = 0.001, 0.045); and NTMG-patients had significantly higher ANC (P = 0.004) compared to other thyroidopathies. Antineutrophil antibodies were found in 37.2% of TD-patients tested. Anti-TPO titers were significantly higher in patients with positive antineutrophil antibodies (P = 0.04). The frequency of TD among neutropenic patients may be higher than previously reported. The existence of antineutrophil antibodies, as well as the different distribution of lymphocyte subsets among patients with different TD, suggests both humoral and cellular mechanisms in the pathophysiology of thyroid disease-associated neutropenia.

A high concentration of triiodothyronine attenuates the stimulatory effect on hemin-induced erythroid differentiation of human erythroleukemia K562 cells

Although thyroid hormone is a known stimulator of erythropoietic differentiation, severe anemia is sometimes observed in patients with hyperthyroidism and this mechanism is not fully understood. The aim of this study was to investigate the effect of triiodothyronine (T3) on hemin-induced erythropoiesis. Human erythroleukemia K562 cells were used as an erythroid differentiation model. Cell differentiation was induced by hemin and the effect of pre-incubation with T3 (0.1 to 100 nM) was analyzed by measuring the benzidine-positive rate, hemoglobin content, CD71 expression (transferrin receptor), and mRNA expression for transcription factors related to erythropoiesis and thyroid hormone receptors (TRs). Hemin, a promoter of erythroid differentiation, increased the levels of mRNAs for TRα, TRβ, and retinoid X receptor α (RXRα), as well as those for nuclear factor-erythroid 2 (NFE2), GATA-binding protein 1 (GATA1) and GATA-binding protein 2 (GATA2). Lower concentrations of T3 had a stimulatory effect on hemin-induced hemoglobin production (1 and 10 nM), CD71 expression (0.1 nM), and α-globin mRNA expression (1 nM), while a higher concentration of T3 (100 nM) abrogated the stimulatory effect on these parameters. T3 at 100 nM did not affect cell viability and proliferation, suggesting that the abrogation of erythropoiesis enhancement was not due to toxicity. T3 at 100 nM also significantly inhibited expression of GATA2 and RXRα mRNA, compared to 1 nM T3. We conclude that a high concentration of T3 attenuates the classical stimulatory effect on erythropoiesis exerted by a low concentration of T3 in hemin-induced K562 cells.

The Role of the Multiple Hormonal Dysregulation in the Onset of "Anemia of Aging": Focus on Testosterone, IGF-1, and Thyroid Hormones

Anemia is a multifactorial condition whose prevalence increases in both sexes after the fifth decade of life. It is a highly represented phenomenon in older adults and in one-third of cases is "unexplained." Ageing process is also characterized by a "multiple hormonal dysregulation" with disruption in gonadal, adrenal, and somatotropic axes. Experimental studies suggest that anabolic hormones such as testosterone, IGF-1, and thyroid hormones are able to increase erythroid mass, erythropoietin synthesis, and iron bioavailability, underlining a potential role of multiple hormonal changes in the anemia of aging. Epidemiological data more consistently support an association between lower testosterone and anemia in adult-older individuals. Low IGF-1 has been especially associated with anemia in the pediatric population and in a wide range of disorders. There is also evidence of an association between thyroid hormones and abnormalities in hematological parameters under overt thyroid and euthyroid conditions, with limited data on subclinical statuses. Although RCTs have shown beneficial effects, stronger for testosterone and the GH-IGF-1 axis and less evident for thyroid hormones, in improving different hematological parameters, there is no clear evidence for the usefulness of hormonal treatment in improving anemia in older subjects. Thus, more clinical and research efforts are needed to investigate the hormonal contribution to anemia in the older individuals.

Thyroid hormone, thyromimetics, and metabolic efficiency

Thyroid hormone (TH) has long been recognized as a major modulator of metabolic efficiency, energy expenditure, and thermogenesis. TH effects in regulating metabolic efficiency are transduced by controlling the coupling of mitochondrial oxidative phosphorylation and the cycling of extramitochondrial substrate/futile cycles. However, despite our present understanding of the genomic and nongenomic modes of action of TH, its control of mitochondrial coupling still remains elusive. This review summarizes historical and up-to-date findings concerned with TH regulation of metabolic energetics, while integrating its genomic and mitochondrial activities. It underscores the role played by TH-induced gating of the mitochondrial permeability transition pore (PTP) in controlling metabolic efficiency. PTP gating may offer a unified target for some TH pleiotropic activities and may serve as a novel target for synthetic functional thyromimetics designed to modulate metabolic efficiency. PTP gating by long-chain fatty acid analogs may serve as a model for such strategy.

The thyroid hormone triiodothyronine controls macrophage maturation and functions: protective role during inflammation

The endocrine system participates in regulating macrophage maturation, although little is known about the modulating role of the thyroid hormones. In vitro results demonstrate a negative role of one such hormone, triiodothyronine (T3), in triggering the differentiation of bone marrow-derived monocytes into unpolarized macrophages. T3-induced macrophages displayed a classically activated (M1) signature. A T3-induced M1-priming effect was also observed on polarized macrophages because T3 reverses alternatively activated (M2) activation, whereas it enhances that of M1 cells. In vivo, circulating T3 increased the content of the resident macrophages in the peritoneal cavity, whereas it reduced the content of the recruited monocyte-derived cells. Of interest, T3 significantly protected mice against endotoxemia induced by lipopolysaccharide i.p. injection; in these damaged animals, decreased T3 levels increased the recruited (potentially damaging) cells, whereas restoring T3 levels decreased recruited and increased resident (potentially beneficial) cells. These data suggest that the anti-inflammatory effect of T3 is coupled to the modulation of peritoneal macrophage content, in a context not fully explained by the M1/M2 framework. Thyroid hormone receptor expression analysis and the use of different thyroid hormone receptor antagonists suggest thyroid hormone receptor β1 as the major player mediating T3 effects on macrophages. The novel homeostatic link between thyroid hormones and the pathophysiological role of macrophages opens new perspectives on the interactions between the endocrine and immune systems.

Thryroid hormones and hematological indices levels in thyroid disorders patients at moi teaching and referral hospital, Western kenya

Problem Statement. Thyroid disorders are prevalent in western Kenya, but the effects of disorders on thyroid hormones and hematological indices levels have not been documented. Study Population. Patients treated for thyroid disorders at the MTRH between January 2008 and December 2011. Objectives. To determine the thyroid hormones and hematological indices levels in thyroid disorders patients at the MTRH, western Kenya. Methodology. A retrospective study in which patient data and stored samples of patients, who presented with thyroid pathologies, underwent thyroidectomy, and histological examinations are done. Thyroid stimulating hormone (TSH), thyroxine (T₄), and triiodothyronine (T₃) blood levels, white blood cells (WBCs), red blood cells (RBCs), platelet counts, and hemoglobin (Hb) levels were analyzed. Results. Male : female ratio was 1 : 10.9 with female representing 368 (95%). The median age was 41 (IQR: 32–48) with a range of 14–89 years. HHormonal levels for immunological thyroid disease patients were higher (P = 0.0232; 0.040) for TSH and (T₃) for those aged 30–39 years, respectively. The WBCs, RBCs, HGB, and platelets in immunological thyroid disease were not statistically significant with P values of 0.547, 0.205, 0.291, and 0.488 respectively. Conclusion. The presence of anaemia due to low RBCs in thyroid disease is not significantly associated with thyroid hormone with a P value of 0.512.

Association between thyroid hormone levels, the number of circulating osteoprogenitor cells, and bone mineral density in euthyroid postmenopausal women

In postmenopausal women, an association between reduced bone mineral density (BMD) and increased number of circulating osteoprogenitor cells (COPs) has been found. Although an increased thyroid function is associated with BMD, thyroid hormones stimulate osteoblast function in vitro. We investigated whether thyroid hormones within the reference range were correlated with the number of COPs and stimulate mineralization in vitro. The number of COPs, defined as CD34+/alkaline phosphatase (AP)+ or CD34+/osteocalcin (OCN)+ cells, was quantified by fluorescence-activated cell sorting (FACS) analysis in 150 euthyroid postmenopausal women. Participants underwent measurement of serum free thyroxine (FT4), thyroid-stimulating hormone levels, and femur BMD. CD34+ cells were isolated from healthy volunteers irrespective of AP or OCN expression, and the effect of triiodothyronine (0.5-10 pmol/L)) on their ability to form mineralized nodules in vitro was studied. The number of COPs was highest among women with high-normal FT4 levels (>1.09 ng/dL). The FT4 levels were correlated positively with circulating log-CD34+/AP+ (r = 0.32, P < .001) and log-CD34/OCN+ cells (r = 0.36, P < .001) and inversely with total femur BMD (r = -0.17, P = .036) but not with femoral neck BMD. In a multivariate analysis, the FT4 levels were positively correlated with the number of COPs, independent of age and BMD. The ability of CD34+ cells to form mineralized nodules increased after exposure from low up to high-normal triiodothyronine concentrations (P for trend = .003). Among euthyroid postmenopausal women, high-normal FT4 levels are correlated with an increased number of circulating immature osteoprogenitor cells and a very mild BMD reduction. Exposure of CD34+ cells to physiological triiodothyronine concentrations stimulates mineralization in vitro.

THRB genetic polymorphisms can predict severe myelotoxicity after definitive chemoradiotherapy in patients with esophageal squamous cell carcinoma

OBJECTIVE

Chemotherapy-related toxicities are difficult to predict before treatment. In this study, we investigated whether thyroid hormone receptor beta (THRB) genetic polymorphisms can serve as a potential biomarker in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Forty-nine Japanese patients with ESCC who received a definitive chemoradiotherapy (CRT) with 5-fluorouracil and cisplatin in conjunction with concurrent irradiation were retrospectively analyzed. Severe acute toxicities, including leukopenia, stomatitis, and cheilitis, were evaluated according to 6 single nucleotide polymorphisms (SNPs) in the gene; the intronic SNPs of rs7635707 G/T, rs6787255 A/C, rs9812034 G/T, and rs9310738 C/T and the SNPs in the 3'-untranslated region (3'-UTR) of rs844107 C/T and rs1349265 G/A.

RESULTS

Distribution of the 4 intronic SNPs, but not the 2 SNPs in the 3'-UTR, showed a significant difference between patients with and without severe acute leukopenia. Stomatitis and cheilitis were not associated with any of the 6 analyzed SNPs. Frequency of haplotype of the 4 intronic SNPs reached approximately 97% with the 2 major haplotypes G-A-G-C (73.4%) and T-C-T-T (23.5%).

CONCLUSIONS

THRB intronic SNPs can provide useful information on CRT-related severe myelotoxicity in patients with ESCC. Future studies will be needed to confirm these findings.

Minireview: Nuclear receptors, hematopoiesis, and stem cells

Nuclear receptors (NRs) regulate a panoply of biological processes, including the function and development of cells within the hematopoietic and immune system, such as erythrocytes, monocytes, and lymphocytes. Significantly less is known regarding the function of NRs in regulating the fate of hematopoietic stem cells (HSCs), the self-renewing, pluripotent cells that give rise to the entirety of the blood and immune systems throughout the lifetime of an individual. Several recent studies suggest, either directly or indirectly, a role for members of the NR family in regulating the differentiation and self-renewal of HSCs, embryonic stem cells, and induced pluripotent stem cells. Herein, we review in detail the function of specific NRs in controlling HSC and other stem cell fate and propose a framework through which these observations can be translated into therapeutic amplification of HSCs for clinical purposes.