Thyroid Disorders in Homozygous β-Thalassemia: Current Knowledge, Emerging Issues and Open Problems

Effects of Thalidomide on Metabolism and Lifespan of Red Blood Cell in Patients With β-Thalassemia Major: A Post Hoc Analysis of a Randomized Controlled Trial

PURPOSE

Recent studies have shown the thalidomide's therapeutic potential in treatment of patients with β-thalassemia major. However, the effect of thalidomide on metabolism and lifespan of red blood cells (RBCs) is rarely reported.

METHODS

This study was a post hoc analysis of a randomized controlled trial (Chinese Clinical Trial Registry, ChiCTR1800015702). One hundred patients with β-thalassemia major were randomly assigned 1:1 to treatment with a placebo or thalidomide. The primary outcomes were the differences in RBC lifespan, reticulocyte count, and peripheral nucleated RBC count of patients after treatment of 12 weeks. Other indicators of hemolytic reaction were also analyzed.

FINDINGS

Compared with the placebo group after treatment of 12 weeks, the thalidomide group showed a longer RBC lifespan (16.29 ± 6.42 vs 12.90 ± 4.98 days; P = 0.004), smaller mean corpuscular volume (68.34 ± 7.79 vs 78.01 ± 6.33 fl; P < 0.001), smaller mean corpuscular hemoglobin (21.62 ± 2.85 vs 24.68 ± 2.69 pg; P < 0.001), and lower lactate dehydrogenase (190.00 [148.00 - 305.00] vs 251.00 [199.20 - 327.80]; P = 0.014). Meanwhile, thalidomide significantly increased the RBC lifespan at 24 weeks (21.24 ± 8.30 days; P < 0.001) and 48 weeks (23.21 ± 8.42 days; P < 0.001) when compared with baseline (12.8 ± 6.0 days).

IMPLICATIONS

Thalidomide increases the RBC lifespan and reduces hemolytic reactions in patients with β-thalassemia major. Chinese Clinical Trial Registry identifier: ChiCTR1800015702.

Reproductive Health in Women with Major β-Thalassemia: Evaluating Ovarian Reserve and Endocrine Complications

Thalassemia is an autosomal recessive hereditary chronic hemolytic anemia characterized by a partial or complete deficiency in the synthesis of alpha- or beta-globin chains, which are essential components of adult hemoglobin. Mutations in the globin genes lead to the production of unstable globin chains that precipitate within cells, causing hemolysis. This shortens the lifespan of mature red blood cells (RBCs) and results in the premature destruction of RBC precursors in the bone marrow. Regular red blood cell transfusions are the standard treatment for thalassemia. However, these transfusions can lead to increased iron overload, which can impair vital systems such as the liver, heart, ovaries, and endocrine system. Focusing on female reproductive endocrinology, recurrent blood transfusions can cause iron accumulation in the pituitary and hypothalamus, leading to hypogonadotropic hypogonadism (HH), the most common endocrinopathy in these patients, affecting 40-91% of women. Recurrent transfusions and the resulting iron overload can also lead to oxidative stress and ovarian damage in patients with beta-thalassemia major (BTM). Despite advancements in iron chelation therapy, hypothalamic-pituitary damage associated with HH contributes to subfertility and sexual dysfunction, often with little to no recovery. In women exposed to gonadotoxic drugs, particularly those with BTM, anti-Mullerian hormone (AMH)-a marker of ovarian reserve-is frequently used to assess ovarian damage. This review aims to explore the pathophysiology of β-thalassemia and its major clinical manifestations, with a focus on endocrine complications and their impact on ovarian reserve. It also investigates how metabolomics can provide insights into the disease's metabolic alterations and inform current and emerging therapeutic strategies to mitigate complications and optimize patient outcomes, potentially leading to more effective and personalized treatments.

Impact of genotype on multi-organ iron and complications in patients with non-transfusion-dependent β-thalassemia intermedia

We evaluated the impact of the genotype on clinical and hematochemical features, hepatic and cardiac iron levels, and endocrine, hepatic, and cardiovascular complications in non-transfusion-dependent (NTD) β-thalassemia intermedia (TI) patients. Sixty patients (39.09 ± 11.11 years, 29 females) consecutively enrolled in the Myocardial Iron Overload in Thalassemia project underwent Magnetic Resonance Imaging to quantify iron overload, biventricular function parameters, and atrial areas and to detect replacement myocardial fibrosis. Three groups of patients were identified: homozygous β+ (N = 18), heterozygous β0β+ (N = 22), and homozygous β0 (N = 20). The groups were homogeneous for sex, age, splenectomy, hematochemical parameters, chelation therapy, and iron levels. The homozygous β° genotype was associated with significantly higher biventricular end-diastolic and end-systolic volume indexes and bi-atrial area indexes. No difference was detected in biventricular ejection fractions or myocardial fibrosis. Extramedullary hematopoiesis and leg ulcers were significantly more frequent in the homozygous β° group compared to the homozygous β+ group. No association was detected between genotype and liver cirrhosis, hypogonadism, hypothyroidism, osteoporosis, heart failure, arrhythmias, and pulmonary hypertension. Heart remodelling related to a high cardiac output state cardiomyopathy, extramedullary hematopoiesis, and leg ulcers were more pronounced in patients with the homozygous β° genotype compared to the other genotypes analyzed. The knowledge of the genotype can assist in the clinical management of NTD β-TI patients.

Growth and endocrinopathies among children with β-Thalassemia major treated at Dubai Thalassemia centre

BACKGROUND

β-Thalassemia major (BTM) is one of the most common hereditary anemias worldwide. Patients suffer from iron overload that results from repeated blood transfusion This in turn leads to multiple organ damage and endocrinopathies. This study aims to assess the prevalence of growth retardation, hypothyroidism, and diabetes mellitus in children and adolescents with BTM treated at Dubai Thalassemia Centre.

METHODS

A total of 105 children and adolescents were included in this retrospective observational study.

RESULTS

39 children and 66 adolescents' data were analyzed. Females composed 51.3% (n = 20) of children and 53.0% (n = 35) of adolescents. Pretransfusion hemoglobin below 9 gm/dl was observed in 10.8% (n = 4) and 10.6% (n = 7) in children and adolescents, respectively. The mean age of menarche was 13.5 years. Among all study participants, 22.6% (n = 14) had normal height velocity whereas 37.1% (n = 23) had reduced height velocity in one year and 40.3% (n = 25) had reduced height velocity in two consecutive years. The proportion of children and adolescents showing reduced height velocity was significantly higher in females compared to the males (90.6% versus 63.3%, respectively, Chi-square = 6.597, p-value = 0.010). Although none of the study participants had diabetes mellitus, 26.1% (n = 12/46) had pre-diabetes. Elevated TSH was observed in 14.7% (n = 5) children and 8.1% (n = 5) adolescents while low FT4 was reported in one child and one adolescent.

CONCLUSION

Of all endocrinopathies seen among children and adolescents with BTM, growth delay remains the main concern for this group of patients. Effective treatment is key to further reducing endocrinopathies. Although the sample size is limited, we postulate that the low percentage of endocrinopathies among children with BTM treated at Dubai thalassemia center and the low level of pretransfusion anemia reflect the effective transfusion and chelation at the center.

Selenium, Iodine and Iron-Essential Trace Elements for Thyroid Hormone Synthesis and Metabolism

The adequate availability and metabolism of three essential trace elements, iodine, selenium and iron, provide the basic requirements for the function and action of the thyroid hormone system in humans, vertebrate animals and their evolutionary precursors. Selenocysteine-containing proteins convey both cellular protection along with H₂O₂-dependent biosynthesis and the deiodinase-mediated (in-)activation of thyroid hormones, which is critical for their receptor-mediated mechanism of cellular action. Disbalances between the thyroidal content of these elements challenge the negative feedback regulation of the hypothalamus-pituitary-thyroid periphery axis, causing or facilitating common diseases related to disturbed thyroid hormone status such as autoimmune thyroid disease and metabolic disorders. Iodide is accumulated by the sodium-iodide-symporter NIS, and oxidized and incorporated into thyroglobulin by the hemoprotein thyroperoxidase, which requires local H₂O₂ as cofactor. The latter is generated by the dual oxidase system organized as 'thyroxisome' at the surface of the apical membrane facing the colloidal lumen of the thyroid follicles. Various selenoproteins expressed in thyrocytes defend the follicular structure and function against life-long exposure to H₂O₂ and reactive oxygen species derived therefrom. The pituitary hormone thyrotropin (TSH) stimulates all processes required for thyroid hormone synthesis and secretion and regulates thyrocyte growth, differentiation and function. Worldwide deficiencies of nutritional iodine, selenium and iron supply and the resulting endemic diseases are preventable with educational, societal and political measures.

Hypothyroidism in children with Hb E/β-thalassemia compared between those who received regular transfusion and those who underwent hematopoietic stem cell transplantation

The studies of hypothyroidism in children with transfusion-dependent hemoglobin E/β-thalassemia (TDT), especially in those who underwent hematopoietic stem cell transplantation (HSCT) are limited. We performed a longitudinal retrospective analysis of thyroid function test (TFT) results among TDT patients aged <25 years who received regular transfusion compared to those who underwent HSCT in Faculty of Medicine Siriraj hospital, Thailand during October 2003 to March 2019. Fifty patients (23 TDT, 27 HSCT) were included. The mean age at the last follow-up was 20.1 ± 2.8 vs. 14.5 ± 4.61 years, respectively. The median age at HSCT was 6 (range: 1.9-13.7) years. The prevalence of hypothyroidism among TDT and post-HSCT was 47.8% and 52.2%, respectively. No study patients showed symptoms or signs of hypothyroidism. Subclinical hypothyroidism was the most common type (63.6% of TDT, and 100% of post-HSCT). We found persistent hypothyroidism in 30.4% of TDT, and in 22.2% of post-HSCT. Thyroxine was given in 1 TDT patient with overt hypothyroidism, and in 3 of 6 post-HSCT patients with persistent subclinical hypothyroidism. The ex-thalassemia patients who underwent HSCT after the age of 10 years had a significantly higher risk of post-HSCT hypothyroidism compared to those who underwent HSCT at the age ≤10 years (hazard ratio: 12.01, 95% confidence interval: 1.65-87.41; p = 0.014). In conclusion, hypothyroidism was found to be common in both TDT and post-HSCT patients. Subclinical hypothyroidism without symptoms and signs was the most common type, and was diagnosed only by TFT screening. Long-term regular surveillance of TFT should be performed in both groups of patients.

New Entity-Thalassemic Endocrine Disease: Major Beta-Thalassemia and Endocrine Involvement

Beta-thalassemia (BTH), a recessively inherited haemoglobin (Hb) disorder, causes iron overload (IO), extra-medullary haematopoiesis and bone marrow expansion with major clinical impact. The main objective of this review is to address endocrine components (including aspects of reproductive health as fertility potential and pregnancy outcome) in major beta-thalassemia patients, a complex panel known as thalassemic endocrine disease (TED). We included English, full-text articles based on PubMed research (January 2017-June 2022). TED includes hypogonadism (hypoGn), anomalies of GH/IGF1 axes with growth retardation, hypothyroidism (hypoT), hypoparathyroidism (hypoPT), glucose profile anomalies, adrenal insufficiency, reduced bone mineral density (BMD), and deterioration of microarchitecture with increased fracture risk (FR). The prevalence of each ED varies with population, criteria of definition, etc. At least one out of every three to four children below the age of 12 y have one ED. ED correlates with ferritin and poor compliance to therapy, but not all studies agree. Up to 86% of the adult population is affected by an ED. Age is a positive linear predictor for ED. Low IGF1 is found in 95% of the population with GH deficiency (GHD), but also in 93.6% of persons without GHD. HypoT is mostly pituitary-related; it is not clinically manifested in the majority of cases, hence the importance of TSH/FT4 screening. HypoT is found at any age, with the prevalence varying between 8.3% and 30%. Non-compliance to chelation increases the risk of hypoT, yet not all studies confirmed the correlation with chelation history (reversible hypoT under chelation is reported). The pitfalls of TSH interpretation due to hypophyseal IO should be taken into consideration. HypoPT prevalence varies from 6.66% (below the age of 12) to a maximum of 40% (depending on the study). Serum ferritin might act as a stimulator of FGF23. Associated hypocalcaemia transitions from asymptomatic to severe manifestations. HypoPT is mostly found in association with growth retardation and hypoGn. TED-associated adrenal dysfunction is typically mild; an index of suspicion should be considered due to potential life-threatening complications. Periodic check-up by ACTH stimulation test is advised. Adrenal insufficiency/hypocortisolism status is the rarest ED (but some reported a prevalence of up to one third of patients). Significantly, many studies did not routinely perform a dynamic test. Atypical EM sites might be found in adrenals, mimicking an incidentaloma. Between 7.5-10% of children with major BTH have DM; screening starts by the age of 10, and ferritin correlated with glycaemia. Larger studies found DM in up to 34%of cases. Many studies do not take into consideration IGF, IGT, or do not routinely include OGTT. Glucose anomalies are time dependent. Emerging new markers represent promising alternatives, such as insulin secretion-sensitivity index-2. The pitfalls of glucose profile interpretation include the levels of HbA1c and the particular risk of gestational DM. Thalassemia bone disease (TBD) is related to hypoGn-related osteoporosis, renal function anomalies, DM, GHD, malnutrition, chronic hypoxia-induced calcium malabsorption, and transplant-associated protocols. Low BMD was identified in both paediatric and adult population; the prevalence of osteoporosis/TBD in major BTH patients varies; the highest rate is 40-72% depending on age, studied parameters, DXA evaluation and corrections, and screening thoracic-lumbar spine X-ray. Lower TBS and abnormal dynamics of bone turnover markers are reported. The largest cohorts on transfusion-dependent BTH identified the prevalence of hypoGn to be between 44.5% and 82%. Ferritin positively correlates with pubertal delay, and negatively with pituitary volume. Some authors appreciate hypoGn as the most frequent ED below the age of 15. Long-term untreated hypoGn induces a high cardiovascular risk and increased FR. Hormonal replacement therapy is necessary in addition to specific BTH therapy. Infertility underlines TED-related hormonal elements (primary and secondary hypoGn) and IO-induced gonadal toxicity. Males with BTH are at risk of infertility due to germ cell loss. IO induces an excessive amount of free radicals which impair the quality of sperm, iron being a local catalyser of ROS. Adequate chelation might improve fertility issues. Due to the advances in current therapies, the reproductive health of females with major BTH is improving; a low level of statistical significance reflects the pregnancy status in major BTH (limited data on spontaneous pregnancies and growing evidence of the induction of ovulation/assisted reproductive techniques). Pregnancy outcome also depends on TED approach, including factors such as DM control, adequate replacement of hypoT and hypoPT, and vitamin D supplementation for bone health. Asymptomatic TED elements such as subclinical hypothyroidism or IFG/IGT might become overt during pregnancy. Endocrine glands are particularly sensitive to iron deposits, hence TED includes a complicated puzzle of EDs which massively impacts on the overall picture, including the quality of life in major BTH. The BTH prognostic has registered progress in the last decades due to modern therapy, but the medical and social burden remains elevated. Genetic counselling represents a major step in approaching TH individuals, including as part of the pre-conception assessment. A multidisciplinary surveillance team is mandatory.

Good Clinical Practice of the Italian Society of Thalassemia and Haemoglobinopathies (SITE) for the Management of Endocrine Complications in Patients with Haemoglobinopathies

Background: The treatment of endocrinopathies in haemoglobinopathies is a continually expanding research area; therefore, recommendations supporting the appropriateness of treatments are a pressing need for the medical community. Methods: The Management Committee of SITE selected and gathered a multidisciplinary and multi-professional team, including experts in haemoglobinopathies and experts in endocrinopathies, who have been flanked by experts with methodological and organizational expertise, in order to formulate recommendations based on the available scientific evidence integrated by personal clinical experience. The project followed the systematic approach for the production of clinical practice guidelines according to the methodology suggested by the National Center for Clinical Excellence, Quality and Safety of Care (CNEC). Results: Out of 14 topics, 100 clinical questions were addressed, and 206 recommendations were elaborated on. The strength of recommendations, panel agreement, a short general description of the topic, and the interpretation of evidence were reported. Conclusions: Good Practice Recommendations are the final outcome of translational research and allow one to transfer to the daily clinical practice of endocrine complications in haemoglobinopathies.

Link between Genotype and Multi-Organ Iron and Complications in Children with Transfusion-Dependent Thalassemia

We evaluated the impact of the genotype on hepatic, pancreatic and myocardial iron content, and on hepatic, cardiac and endocrine complications in children with transfusion-dependent β-thalassemia (β-TDT). We considered 68 β-TDT patients (11.98 ± 3.67 years, 51.5% females) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia network. Iron overload was quantified by T2* technique and biventricular function by cine images. Replacement myocardial fibrosis was evaluated by late gadolinium enhancement technique. Three groups of patients were identified: homozygous β+ (N = 19), compound heterozygous β0β+ (N = 24), and homozygous β0 (N = 25). The homozygous β0 group showed significantly lower global heart and pancreas T2* values than the homozygous β+ group. Compared to patients with homozygous β+ genotype, β0β+ as well as β0β0 patients were more likely to have pancreatic iron overload (odds ratio = 6.53 and 10.08, respectively). No difference was detected in biventricular function parameters and frequency of replacement fibrosis. No patient had cirrhosis/fibrosis, diabetes or heart failure, and the frequency of endocrinopathies was comparable among the groups. In pediatric β-TDT patients, there is an association between genotype and cardiac and pancreatic iron overload. The knowledge of patients’ genotype can be valuable in predicting some patients’ phenotypic features and in helping the clinical management of β-TDT patients.

A Short Review on Growth and Endocrine Long-term Complications in Children and Adolescents with β-Thalassemia Major: Conventional Treatment versus Hematopoietic Stem Cell Transplantation

The conventional treatment of β-thalassemia (β-TM) patients is based on the correction of anemia through regular blood transfusions and iron chelation therapy. However, allogeneic hematopoietic stem cell transplantation (HSCT) remains the only currently available technique that has curative potential. Variable frequency and severity of long-term growth and endocrine changes after conventional treatment as well as after HSCT have been reported by different centers. The goal of this mini-review is to summarize and update knowledge about long-term growth and endocrine changes after HSCT in patients with β-TM in comparison to those occurring in β-TM patients on conventional treatment. Regular surveillance, early diagnosis, treatment, and follow-up in a multi-disciplinary specialized setting are suggested to optimize the patient's quality of life (www.actabiomedica.it).

Detection of endocrine disorders in young children with multi-transfused thalassemia major

BACKGROUND

Beta thalassemia major (TM) is the most common inherited genetic disorder worldwide. Patients are at risk of iron overload, which leads to various forms of tissue damage, including endocrinopathies. The aim of this study was to evaluate the prevalence and risk factors of endocrine disorders in young patients with multi-transfused TM receiving iron chelation therapy.

METHODS

The inclusion criteria included all known cases of TM according to hemoglobin electrophoresis data, aged 12 years or younger, during the study period. The patient's age, gender, parent's consanguinity, clinical examination, and types of iron chelating agents used were recorded. Serum ferritin level, complete blood count (CBC), blood glucose homeostasis, thyroid, and parathyroid functions were determined.

RESULTS

One hundred twenty patients met the inclusion criteria; 70% of them had malnutrition. The presence of endocrine disorders was observed in 28/120 (23.33%) patients. The most common endocrine disorders were thyroid disorders, either subclinical or clinical hypothyroidism in 11/120 (9.17%) patients, followed by abnormalities in glucose homeostasis 9/120 (7.5%). The prevalence of impaired glucose tolerance, impaired fasting glucose, and diabetes mellitus in the present study was 5 (4.17%), 4 (3.33%), and 0 (00%), respectively, while the least frequent endocrine disorder seen in our patients was hypoparathyroidism in 8/120 (6.66%). We noted that high serum ferritin levels and poor patient compliance to therapy were significantly associated with increased endocrine disorders (OR 0.98, 95% CI 0.96-0.99, P = 0.003 and OR 0.38, 95% CI 0.16:0.93, P = 0.03, respectively). Combined chelating iron agents significantly decreased the prevalence of endocrine disorders when compared with monotherapy (OR 0.40, 95% CI 0.16:0.97, P = 0.04).

CONCLUSION

Endocrine disorders could occur in TM patients early before or equal to 12 years of life in about one-fourth of the patients. A high serum ferritin level and poor patient compliance to therapy were significantly associated with increased endocrine disorders. Combined iron-chelating agents were associated with a decreased prevalence of endocrine disorders when compared with monotherapy.

Iatrogenic Iron Overload in an End Stage Renal Disease Patient

Iron overload is a common complication in patients with chronic renal failure treated with dialysis prior to the availability of recombinant human erythropoietin therapy. Iron overload was the result of hypoproliferative erythroid marrow function coupled with the need for frequent red blood cell transfusions to manage symptomatic anemia. The repetitive use of intravenous iron with or without the use of red blood cell transfusions also contributed to iron loading and was associated with iron deposition in liver parenchymal and reticuloendothelial cells. Here we report a 56-year-old female with end-stage renal failure who underwent kidney transplant twice and found to have iatrogenic iron overload with excess intravenous iron treated conservatively.

Implications of SARSr-CoV 2 infection in thalassemias: Do patients fall into the "high clinical risk" category?

We're all flying blind regarding coronavirus, but it's fair to think if thalassemic patients are particularly vulnerable to SARS-COV-2  infection or are at potential higher risk of complications from COVID-19 than normal population, specially when they become older. The frustrating thing is that, right now,  this virus is still new. It only came to the attention of the World Health Organization at the end of December. Very few cases in thalassemia have so far been reported; is this due to lack of testing or a true lack of infection/susceptibility? However, we believe that more data should be collected to better characterise the impact of SARS-CoV-2 infection in patients with thalassemias. Therefore, a multicenter registry and the collection of comprehensive data from both positive COVID-19 thalassemia major and non-transfusion dependent thalassemia are necessary to clarify debated issues. In the meantime an early and vigilant monitoring along with high quality supportive care are needed in thalassemic patients at high risk for SARS-CoV-2 infection.

Thalidomide for Patients with β-Thalassemia: A Multicenter Experience

Objective

This study focused on the efficacy and safety of thalidomide for patients with β-thalassemia in a multicenter trial.

Methods

Patients with non-transfusion-dependent thalassemia (NTDT) or transfusion-dependent thalassemia (TDT), who were unable to pursue conventional therapy with transfusion and chelation, were recruited over 3 years in three centers in southern China. We evaluated the efficacy and safety of thalidomide in the short-term (three months) and long-term follow-up (12 and 24 months). Response to thalidomide was defined as follows: Main Responder (MaR) showing an increase in hemoglobin (Hb) level of >2.0 g/dl or free from blood transfusion and Minor Responder (MiR) achieving elevated Hb level of 1.0–2.0 g/dl or ≥50% reduction in blood transfusion frequency.

Results

The overall response rate (ORR) was 93.5%, with MaR and MiR rates accounting for 62.9% and 30.6% in short-term follow-up. For patients with NTDT, the Hb level increased from a baseline mean of 6.8±1.1 g/dl to 9.7±1.9 g/dl (P<0.001). Elevated Hb was mainly attributable to increased fetal hemoglobin (HbF) levels. Among patients with TDT, while an increase in the average Hb concentration was observed, there was a significant drop in yearly transfusions from 20.7±7.7 to 5.8±6.8 blood units per year (P<0.001). The response of patients in both categories was sustained even after an average follow up of 14.6±9.6 months (3–37 months). Minimal side-effects were documented throughout, except peripheral neurotoxicity in one patient. Logistic regression analysis identified the ratio of HbF at baseline (P=0.038, OR=1.111, 95% CI: 1.006–1.226) as an independent risk factor for the primary response to thalidomide.

Conclusion

Thalidomide had significant therapeutic effects on patients with β-thalassemia with a sustained response. Peripheral neuropathy is one of the most feared complications. While these preliminary results support the potential long-term efficacy of thalidomide as a therapeutic agent for β-thalassemia, several issues need to be addressed before its application in the clinic.

Does Splenectomy Influence the Development of Hypothyroidism in Transfusion Dependent Thalassemia Patients? A Retrospective Study

To test the postulated hypothesis that splenectomy may influence the development of Hypothyroisdism (HT) in Transfused Dependent Thalassemia (TDT) young patients, basic factors known to influence the development of hypothyroidism were evaluated in 52 TDT adult patients (25 splenectomized) with HT. Precise analysis of data not only failed to disclose any statistical differences but revealed similarities, between splenectomized and non- splenectomized patients in respect to: i) the age at diagnosis of HT and ii)the ferritin levels on diagnosis and at the year of study. Interestingly a statistically higher age at diagnosis was recorded in central HT irrespective of splenectomy.