Recovery of age-dependent immunological deterioration in old mice by thyroxine treatment

Hypothyroidism as an Independent Predictor of 30-day Readmission in Head and Neck Cancer Patients

OBJECTIVES

To define the role of hypothyroidism and other risk factors for unplanned readmissions after surgery for head and neck cancer.

STUDY DESIGN

Retrospective cohort study.

METHODS

The Nationwide Readmission Database (NRD) was used to identify patients who underwent surgery for mucosal head and neck cancer (oral cavity, oropharynx, larynx, and hypopharynx) between 2010 and 2017. Univariate and multivariate logistic regression were performed to determine patient, tumor, and hospital related risk factors for 30-day readmission. Readmitted patients were stratified by preoperative diagnosis of hypothyroidism to compare readmission characteristics.

RESULTS

For the 131,013 patients who met inclusion criteria, the readmission rate was 15.9%. Overall, 11.91% of patients had a preoperative diagnosis of hypothyroidism. After controlling for other variables, patients with a preoperative diagnosis of hypothyroidism had 12.2% higher odds of readmission compared to those without hypothyroidism (OR: 1.12, 1.03-1.22, p = 0.008). Patients with hypothyroidism had different reasons for readmission, including higher rates of wound dehiscence, fistula, infection, and electrolyte imbalance. Among readmitted patients, the length of stay for index admission (mean 10.5 days vs. 9.2 days, p < 0.001), readmission (mean 7.0 vs. 6.6 days, p = 0.05), and total hospital charge were higher for hypothyroid patients ($137,742 vs. $119,831, p < 0.001).

CONCLUSION

Hypothyroidism is an independent risk factor for 30-day readmission following head and neck cancer resection. Furthermore, hypothyroid patients are more likely to be readmitted for wound complications, infection, and electrolyte imbalance. Targeted interventions should be considered for hypothyroid patients to decrease readmission rates and associated patient morbidity, potentially leading to earlier initiation of adjuvant treatment.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2988-2998, 2023.

The role of hormones in sepsis: an integrated overview with a focus on mitochondrial and immune cell dysfunction

Sepsis is a dysregulated host response to infection that results in life-threatening organ dysfunction. Virtually every body system can be affected by this syndrome to greater or lesser extents. Gene transcription and downstream pathways are either up- or downregulated, albeit with considerable fluctuation over the course of the patient's illness. This multi-system complexity contributes to a pathophysiology that remains to be fully elucidated. Consequentially, little progress has been made to date in developing new outcome-improving therapeutics. Endocrine alterations are well characterised in sepsis with variations in circulating blood levels and/or receptor resistance. However, little attention has been paid to an integrated view of how these hormonal changes impact upon the development of organ dysfunction and recovery. Here, we present a narrative review describing the impact of the altered endocrine system on mitochondrial dysfunction and immune suppression, two interlinked and key aspects of sepsis pathophysiology.

Regulation of metabolic and transcriptional responses by the thyroid hormone in cellular models of murine macrophages

Oncogene-immortalized bone marrow-derived macrophages are considered to be a good model for the study of immune cell functions, but the factors required for their survival and proliferation are still unknown. Although the effect of the thyroid hormones on global metabolic and transcriptional responses in macrophages has not yet been examined, there is increasing evidence that they could modulate macrophage functions. We show here that the thyroid hormone T3 is an absolute requirement for the growth of immortal macrophages. The hormone regulates the activity of the main signaling pathways required for proliferation and anabolic processes, including the phosphorylation of ERK and p38 MAPKs, AKT, ribosomal S6 protein, AMPK and Sirtuin-1. T3 also alters the levels of metabolites controlling transcriptional and post-transcriptional actions in macrophages, and causes widespread transcriptomic changes, up-regulating genes needed for protein synthesis and cell proliferation, while down-regulating genes involved in immune responses and endocytosis, among others. This is not observed in primary bone marrow-derived macrophages, where only p38 and AMPK activation is regulated by T3 and in which the metabolic and transcriptomic effects of the hormone are much weaker. However, the response to IFN-γ is reduced by T3 similarly in immortalized macrophages and in the primary cells, confirming previous results showing that the thyroid hormones can antagonize JAK/STAT-mediated signaling. These results provide new perspectives on the relevant pathways involved in proliferation and survival of macrophage cell culture models and on the crosstalk between the thyroid hormones and the immune system.

Infection-Associated Thymic Atrophy

The thymus is a vital organ of the immune system that plays an essential role in thymocyte development and maturation. Thymic atrophy occurs with age (physiological thymic atrophy) or as a result of viral, bacterial, parasitic or fungal infection (pathological thymic atrophy). Thymic atrophy directly results in loss of thymocytes and/or destruction of the thymic architecture, and indirectly leads to a decrease in naïve T cells and limited T cell receptor diversity. Thus, it is important to recognize the causes and mechanisms that induce thymic atrophy. In this review, we highlight current progress in infection-associated pathogenic thymic atrophy and discuss its possible mechanisms. In addition, we discuss whether extracellular vesicles/exosomes could be potential carriers of pathogenic substances to the thymus, and potential drugs for the treatment of thymic atrophy. Having acknowledged that most current research is limited to serological aspects, we look forward to the possibility of extending future work regarding the impact of neural modulation on thymic atrophy.

Thyrotrophin and thyroxine support immune homeostasis in humans

The endocrine and the immune systems interact by sharing receptors for hormones and cytokines, cross‐control and feedback mechanisms. To date, no comprehensive study has assessed the impact of thyroid hormones on immune homeostasis. By studying immune phenotype (cell populations, antibody concentrations, circulating cytokines, adipokines and acute‐phase proteins, monocyte–platelet interactions and cytokine production capacity) in two large independent cohorts of healthy volunteers of Western European descent from the Human Functional Genomics Project (500FG and 300BCG cohorts), we identified a crucial role of the thyroid hormone thyroxin (T4) and thyroid‐stimulating hormone (TSH) on the homeostasis of lymphocyte populations. TSH concentrations were strongly associated with multiple populations of both effector and regulatory T cells, whereas B‐cell populations were significantly associated with free T4 (fT4). In contrast, fT4 and TSH had little impact on myeloid cell populations and cytokine production capacity. Mendelian randomization further supported the role of fT4 for lymphocyte homeostasis. Subsequently, using a genomics approach, we identified genetic variants that influence both fT4 and TSH concentrations and immune responses, and gene set enrichment pathway analysis showed enrichment of fT4‐affected gene expression in B‐cell function pathways, including the CD40 pathway, further supporting the importance of fT4 in the regulation of B‐cell function. In conclusion, we show that thyroid function controls the homeostasis of the lymphoid cell compartment. These findings improve our understanding of the immune responses and open the door for exploring and understanding the role of thyroid hormones in the lymphocyte function during disease.

Hypothyroidism impairs the host immune response during the acute phase of Chagas disease

Diseases associated with thyroid hypofunction have been the subject of studies in infectious models, since several authors have demonstrated a pivotal role of iodinated hormones (thyroxine and triiodothyronine) in the modulation of immune effector responses. Using a model of hypothyroidism induced by anti-thyroid drug, we investigated the influence of hypothyroidism in the course of acute Trypanosoma cruzi infection. For this, male Hannover Wistar rats were challenged with methimazole for 21 days (0.02% in drinking water), and water for control counterparts. After confirmation of the hypothyroidism, rats were intraperitoneally challenged with 1x10⁵ blood trypomastigotes of the Y strain of T. cruzi. Our findings suggest that hypothyroidism impairs animal weight gain, but does not affect the health of essential organs. Interestingly, infected hypothyroid animals had a significant increase in thymic cell death, with consequent drop in lymphocyte frequency in whole blood (evaluated on the 11th day of infection). Analyzing the percentage of immune cells in the spleen, we found a strong influence of hypothyroidism as a negative regulator of B cells, and antigenic ability of macrophages (RT1b expression) in the course of the experimental chagasic infection. Enhanced serum IL-17A concentration was induced by T. cruzi infection, but hypothyroidism impaired the production of this mediator as seen in infected hypothyroid animals. Taken together, our work suggests for the first time that hypothyroidism may adversely interfere with the modulation of effective immunity in the early phase of Chagas' disease.

[Safety and effectiveness of total hip arthroplasty in patients with hypothyroidism]

Objective

To evaluate the safety and effectiveness of total hip arthroplasty (THA) in patients with hypothyroidism.

Methods

Sixty-three patients with hypothyroidism (hypothyroidism group) and 63 euthyroid patients without history of thyroid disease (control group) who underwent primary unilateral THA between November 2009 and November 2018 were enrolled in this retrospective case control study. There was no significant difference between the two groups in gender, age, body mass index, hip side, reason for THA, American Society of Anesthesiology (ASA) classification, preoperative hemoglobin (Hb) level, and preoperative Harris score ( P>0.05). The perioperative thyroid stimulating hormone (TSH) and thyroxine (T ₄) levels, the hypothyroidism-related and other complications during hospitalization, the decrease in Hb, perioperative total blood loss, blood transfusion rate, length of hospital stays, and 90 days readmissions rate in the two groups were recorded and evaluated. The periprosthetic joint infection, aseptic loosening of the prosthesis, and hip Harris score during follow-up were recorded.

Results

The differences in the TSH and T ₄ of hypothyroidism group between pre- and 3 days post-operation were significant ( P>0.05) and no hypothyroidism-related complications occurred after THA. The decrease in Hb and perioperative total blood loss in the hypothyroidism group were significantly higher than those in the control group ( P<0.05), but there was no significant difference between the two groups in terms of transfusion rate, length of hospital stays, and 90 days readmission rates ( P>0.05). No significant difference in the rate of complications (liver dysfunction, heart failure, pulmonary infection, urinary infection, and wound complication) between the two groups was found ( P>0.05) except for the rate of intramuscular vein thrombosis which was significantly lower in the hypothyroidism group, and the rate of postoperative anemia which was significantly higher in the hypothyroidism group ( P<0.05). The two groups were followed up 1.0-9.9 years (mean, 6.5 years). At last follow-up, Harris score in both groups were significantly higher than those before operation ( P<0.05). An increase of 39.5±12.3 in hypothyroidism group and 41.3±9.3 in control group were recorded, but no significant difference was found between the two groups ( t=0.958, P=0.340). During the follow-up, 1 case of periprosthetic joint infection occurred in the hypothyroidism group, no loosening or revision was found in the control group.

Conclusion

With the serum TSH controlled within 0.5-3.0 mU/L and T ₄ at normal level preoperatively, as well as the application of multiple blood management, hypothyroid patients can safely go through THA perioperative period and effectively improve joint function, quality of life, and obtain good mid-term effectiveness.

Does well-controlled overt hypothyroidism increase the risk of total knee arthroplasty?

BACKGROUND

Overt hypothyroidism is widely accepted as a risk factor for adverse events following total knee arthroplasty (TKA). However, no prior study has preoperatively reversed hypothyroidism and reevaluated its risk. This retrospective study aimed at investigating whether well-controlled overt hypothyroidism would still increase the risk of TKA.

METHODS

Between November 2009 and November 2016, patients diagnosed with overt hypothyroidism but well controlled and underwent TKA were compared with euthyroid TKA patients. Data were extracted from our departmental database. Chi-squared test and t-tests were used for comparisons.

RESULTS

Hypothyroid patients had more blood loss and lower postoperative haemoglobin (Hb) and haematocrit level than the control group (all P < 0.05). Although the postoperative anaemia rate was lower in the control group (P = 0.01), there was no significant difference in the transfusion rate between the two groups (2.99% versus 7.46%, P = 0.10) or in the rates of other complications (P > 0.05). Interestingly, intramuscular venous thrombosis rate in hypothyroid patients was significantly lower than that in the control group (1.49% versus 9.70%, P = 0.00). Clinical outcome scores were comparable between the two groups throughout the course. And only one case of infection occurred in the hypothyroid patients.

CONCLUSION

Well-controlled overt hypothyroidism did not increase the risk of TKA, except for perioperative blood loss. Surgeons should be aware that even if hypothyroidism is reversed, the risk of more perioperative blood loss still exists and that, consequently, perioperative blood management is still essential in this population.

Thyroid Hormone Action on Innate Immunity

The interplay between thyroid hormone action and the immune system has been established in physiological and pathological settings. However, their connection is complex and still not completely understood. The thyroid hormones (THs), 3,3',5,5' tetraiodo-L-thyroxine (T4) and 3,3',5-triiodo-L-thyronine (T3) play essential roles in both the innate and adaptive immune responses. Despite much research having been carried out on this topic, the available data are sometimes difficult to interpret or even contradictory. Innate immune cells act as the first line of defense, mainly involving granulocytes and natural killer cells. In turn, antigen presenting cells, macrophages and dendritic cells capture, process and present antigens (self and foreign) to naïve T lymphocytes in secondary lymphoid tissues for the development of adaptive immunity. Here, we review the cellular and molecular mechanisms involved in T4 and T3 effects on innate immune cells. An overview of the state-of-the-art of TH transport across the target cell membrane, TH metabolism inside these cells, and the genomic and non-genomic mechanisms involved in the action of THs in the different innate immune cell subsets is included. The present knowledge of TH effects as well as the thyroid status on innate immunity helps to understand the complex adaptive responses achieved with profound implications in immunopathology, which include inflammation, cancer and autoimmunity, at the crossroads of the immune and endocrine systems.

Increased Risk of Periprosthetic Joint Infections in Patients With Hypothyroidism Undergoing Total Joint Arthroplasty

BACKGROUND

Although thyroxine has an important role in modulating the immune system, it has not been associated with periprosthetic joint infection. This study was conceived to examine the association between hypothyroidism and periprosthetic joint infection (PIJ).

METHODS

Using an institutional database, the preoperative comorbidities of 32,289 total joint arthroplasties performed between 2000 and 2013 were identified using an International Classification of Diseases, Ninth Revision-based comorbidity index.

RESULTS

In the multivariate analysis, hypothyroidism was found to be an independent risk factor (adjusted odds ratio: 2.46; P < .0001). In addition, patients who developed PJI demonstrated higher thyroid-stimulating hormone levels than those without (P = .04).

DISCUSSION

Surgeons should be aware of this increased risk of PJI in hypothyroid patients when risk stratifying, and future studies are needed to determine the potential role of thyroxine supplementation.

Thyroid hormones and their membrane receptors as therapeutic targets for T cell lymphomas

Thyroid hormones (THs) are important regulators of metabolism, differentiation and cell proliferation. They can modify the physiology of human and murine T cell lymphomas (TCL). These effects involve genomic mechanisms, mediated by specific nuclear receptors (TR), as well as nongenomic mechanisms, that lead to the activation of different signaling pathways through the activation of a membrane receptor, the integrin αvβ3. Therefore, THs are able to induce the survival and growth of TCL. Specifically, the signaling induced by THs through the integrin αvβ3 activates proliferative and angiogenic programs, mediated by the regulation of the vascular endothelial growth factor (VEGF). The genomic or pharmacologic inhibition of integrin αvβ3 reduces the production of VEGF and induces cell death both in vitro and in xenograft models of human TCL. Here we review the mechanisms involved in the modulation of the physiology of TCL induced by THs, the analysis of the interaction between genomic and nongenomic actions of THs and their contribution to T cell lymphomagenesis. These actions of THs suggest a novel mechanism for the endocrine modulation of the physiopathology of TCL and they provide a potential molecular target for its treatment.

Hormones and immunity in cancer: are thyroid hormones endocrine players in the microglia/glioma cross-talk?

Accumulating evidence indicates that the endocrine and immune systems engage in complex cross-talks in which a prominent role is played by thyroid hormones (THs). The increase of resident vs. monocyte recruited macrophages was shown to be an important effector of the TH 3,3′,5′-Triiodo-L-thyronine (T3)-induced protection against inflammation and a key role of T3 in inhibiting the differentiation of peripheral monocytes into macrophages was observed. Herein, we report on the role of T3 as a modulator of microglia, the specialized macrophages of the central nervous system (CNS). Mounting evidence supports a role of microglia and macrophages in the growth and invasion of malignant glioma. In this respect, we unveil the putative involvement of T3 in the microglia/glioma cell communication. Since THs are known to cross the blood-brain barrier, we suggest that T3 not only exerts a direct modulation of brain cancer cell itself but also indirectly promotes glioma growth through a modulation of microglia. Our observations expand available information on the role of TH system in glioma and its microenvironment and highlight the endocrine modulation of microglia as an important target for future therapeutic development of glioma treatments.

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.

Extensive viral mimicry of 22 AIDS-related autoantigens by HIV-1 proteins and pathway analysis of 561 viral/human homologues suggest an initial treatable autoimmune component of AIDS

HIV-1 viral proteins, particularly the env protein, are homologous to 22 AIDS autoantigens, suggesting their creation by antiviral antibodies subsequently targeting human homologues. They include antibodies to T-cell receptors, CD4 and CD95, complement components, IgG, TNF and other immune-related proteins. Autoantibodies may compromise the immune system via knockdown of these key proteins, and autoimmune attack on the immune system itself, as supported by immune activation in early stages of infection and during the transition to AIDS. Over 500 human proteins contain pentapeptides or longer consensi, identical to viral peptides. Such homology explains the extensive viral/human interactome, likely related to the ability of viral homologues to compete with human counterparts as binding partners. Pathway analysis of these homologous proteins revealed their involvement in immune-related networks (e.g. natural killer cell toxicity/toll, T-cell/B-cell receptor signalling/antigen processing) and viral and bacterial entry and defence pathways (phagosome/lysosome pathways, DNA sensing/NOD/RIG-1 pathways) relevant to AIDS pathogenesis. At its inception, AIDS may have an autoimmune component selectively targeting the immune system. Immunosuppressive therapy or antibody removal, which has already achieved some success, might be therapeutically beneficial, particularly if targeted at removal of the culpable antibodies, via affinity dialysis.

Thyroid hormones as modulators of immune activities at the cellular level

BACKGROUND

Increasing evidence suggests that thyroid hormones, L-thyroxine (T(4)) and 3,3',5-triiodo-L-thyronine (T(3)), are modulators of the immune response. In monocytes, macrophages, leukocytes, natural killer cells, and lymphocytes, a wide range of immune functions such as chemotaxis, phagocytosis, generation of reactive oxygen species (ROS), and cytokine synthesis and release are altered under hypo- and hyperthyroid conditions.

SUMMARY

Hyperthyroidism decreases the proinflammatory activities of monocytes and macrophages, whereas enhancement of phagocytosis and increased levels of ROS may occur during hypothyroidism. The expression of proinflammatory molecules such as macrophage inflammatory protein-1α and interleukin-1β increases in hypothyroidism. However, in Kupffer cells, proinflammatory activities such as the respiratory burst, nitric oxide synthase activity, and tumor necrosis factor-α expression may result from increased T(3) levels. Thyroid hormones also affect natural killer cell activity and cell-mediated immune responses. Still, for many immune cells no clear correlation has been found so far between abnormally high or low T(3) or T(4) levels and the effects observed on the immune responses.

CONCLUSIONS

In this review we outline the contributions of thyroid hormones to different aspects of innate and adaptive immune responses. The relationship between thyroid hormones and immune cells is complex and T(3) and T(4) may modulate immune responses through both genomic and nongenomic mechanisms. Future studies of the molecular signaling mechanisms involved in this cross-talk between thyroid hormones and the immune system may support development of new strategies to improve clinical immune responses.

Baseline predictors of virological response for chronic hepatitis B patients

AIM: To determine which baseline factors of chronic hepatitis B patients are predictive of virological response to Peginterferon α-2b therapy.

METHODS: A total of 21 HBeAg-positive chronic hepatitis B (CHB) patients treated with Peginterferon α-2b were recruited. They were treated with Peginterferon α-2b (0.5-1.0 μg/kg per week) for 24 wk and followed up for 24 wk. Clinical and laboratory data of the patients were determined at pretreatment and at week 12, at 24 during treatment, and at week 48 during follow up.

RESULTS: Ten patients achieved a virological response at the end of treatment. Their baseline serum alanine aminotransferase (ALT), thyroid-stimulating hormone (TSH), and total thyroxin (TT4) levels were significantly different from those who failed treatment. The positive predictive values (PPV) and negative predictive values (NPV) of ALT, TSH, and TT4 were 75% and 89 %, 75% and 89 %, and 75% and 75%, respectively. Moreover, combinations of the baseline ALT and TT4, ALT and TSH, TT4 and TSH levels had much higher PPV and NPV (86% and 88%, 89% and 100%, 83% and 100%, respectively).

CONCLUSION: Baseline serum ALT, TSH, and TT4 levels, especially in combination, have high predictive values of virological response to Peginterferon α-2b in HBeAg-positive CHB patients.

Mucosal adjuvant activity of flagellin in aged mice

We evaluated the ability of flagellin, a highly effective mucosal adjuvant in mice and non-human primates, to promote mucosal innate and adaptive immunity in aged mice. We found that intratracheal instillation of flagellin induced a stronger respiratory innate response in aged mice than in young mice, and that intranasal instillation of flagellin was equally effective at triggering recruitment of T and B lymphocytes to the draining lymph nodes of young and aged mice. Intranasal immunization of aged mice with flagellin and the Yersinia pestis protein F1 promoted specific IgG and IgA production, but at lower levels and lower avidities than in young mice. Although intranasal instillation of flagellin and F1 antigen increased germinal center formation and size in young mice, it did not do so in aged mice. Our findings are consistent with the conclusion that flagellin can promote adaptive immune responses in aged mice, but at a less robust level than in young mice.

Triiodothyronine modulates differential homing of recent thymic emigrants to peripheral lymphoid organs

The functioning of the immune system partially relies on T-cell exportation from the thymus, the major site of T-cell differentiation. Although the molecular mechanisms governing this process begin to be elucidated, it is not clear if thyroid hormones can alter the homing of recent thymic emigrants (RTE) to peripheral lymphoid organs. Herein, we investigated whether triiodothyronine (T(3)) could influence the homing of thymus-derived T cells. For that we used intrathymic injection of T(3) in combination with fluorescein isothiocyanate (FITC) to trace, 16 h later, FITC(+) cells, termed RTE, in peripheral lymphoid organs. We observed that T(3) stimulated thymocyte export, increasing the frequency of CD4(+) RTE and CD8(+) RTE in the subcutaneous and mesenteric lymph nodes. By contrast, the relative numbers of CD4(+) RTE in the spleen were decreased. T(3) also changed the differential distribution pattern of CD4(+) RTE, and to a lesser extent CD8(+) RTE in the peripheral lymphoid organs. Moreover, the expression of extracellular matrix (ECM) components, such as laminin and fibronectin, which are known to be involved in T-cell migration, increased in the lymph nodes but not in the spleen following intrathymic T(3) treatment. In conclusion, our data correspond to the first demonstration that in vivo treatment with thyroid hormone stimulates thymic T-cell homing and T-cell distribution in peripheral lymphoid organs.