Biochemical markers of glucose metabolism may be used to estimate the degree and progression of iron overload in the liver and pancreas of patients with β-thalassemia major

β-Thalassemia and Diabetes Mellitus: Current State and Future Directions

β-Thalassemia major is a congenital hemoglobin disorder that requires regular blood transfusion. The disease is often associated with iron overload and diabetes mellitus, among other complications. Pancreatic iron overload in β-thalassemia patients disrupts β-cell function and insulin secretion and induces insulin resistance. Several risk factors, including family history of diabetes, sedentary lifestyle, obesity, gender, and advanced age increase the risk of diabetes in β-thalassemia patients. Precautionary measures such as blood glucose monitoring, anti-diabetic medications, and healthy living in β-thalassemia patients notwithstanding, the prevalence of diabetes in β-thalassemia patients continues to rise. This review aims to address the relationship between β-thalassemia and diabetes in an attempt to understand how the pathology and management of β-thalassemia precipitate diabetes mellitus. The possible employment of surrogate biomarkers for early prediction and intervention is discussed. More work is still needed to better understand the molecular mechanism(s) underlying the link between β-thalassemia and diabetes and to identify novel prognostic and therapeutic targets.

Upregulation of Nrf2 Signalling and the Inhibition of Erastin-Induced Ferroptosis by Ferulic Acid in MIN6 Cells

Ferroptosis is a regulated cell death process characterised by the iron-dependent accumulation of oxidised polyunsaturated fatty acid-containing phospholipids. Its initiation is complicated and involves reactive oxygen species (ROS) and a loss of the activity of the lipid repair enzyme glutathione peroxidase 4 (GPX4). These play critical roles in the development of ferroptotic cell damage by lipid peroxidation. Antioxidant therapy is a promising therapeutic strategy to prevent or even reverse the progression of ferroptosis. This study was designed to demonstrate the protective effect of ferulic acid (FA) against oxidative stress and erastin-mediated ferroptosis in murine MIN6 cells. Cells were treated with FA or its metabolite ferulic acid 4-O-sulfate disodium salt (FAS) and 20 μM of erastin. Cell viability was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay, iron levels were measured by inductively coupled plasma mass spectrometry (ICP-MS), ROS levels were determined by a dihydrodichlorofluorescein (H2DCF) cell-permeant probe, and glutathione and lipid peroxidation were assayed with commercially available kits. The phenolic acids enhanced cell viability in erastin-treated MIN6 cells in a dose-dependent manner. Furthermore, MIN6 cells exposed to erastin alone showed elevated levels of iron and ROS, glutathione (GSH) depletion, and lipid peroxidation (p < 0.05) compared to cells that were protected by co-treatment with FA or FAS. The treatment of MIN6 cells with FA or FAS following exposure to erastin increased the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) protein levels. Consequently, levels of its downstream antioxidant proteins, HO-1, NQO1, GCLC, and GPX4, increased. FA and FAS greatly decreased erastin-induced ferroptosis in the presence of the Nrf2 inhibitor, ML385, through the regulation of Nrf2 response genes. In conclusion, these results show that FA and FAS protect MIN6 cells from erastin-induced ferroptosis by the Nrf2 antioxidant protective mechanism.

Indicators of glucose dysregulation and the relationship with iron overload in Chinese children with beta thalassemia major

INTRODUCTION

Patients with beta thalassemia major (TM) have a higher risk of diabetes and an abnormal oral glucose tolerance test (OGTT), but there is no single agree monitoring parameter that reflects glycemic status. The possible mechanisms include iron overload and blood transfusion, but they require further investigation.

PURPOSE

This study explored the role of glycated hemoglobin A1c (HbA1c), fructosamine, and glycated albumin (GA) in evaluating the glucose dysregulation and to determine the potential relationship between iron deposition and glucose metabolism disorder in beta TM.

METHODS

A cross-sectional study was performed on 118 patients with beta TM and the control group consisted of 33 healthy children with no statistical differences in age, sex, and body mass index (BMI). Fast plasma glucose (FPG), fast insulin (FINS), insulin resistance index (HOMA-IRI), and insulin sensitivity index (HOMA-ISI) were compared between the patient and control groups. HbA1c, GA, fructosamine, and serum ferritin (SF) were measured in the patient group. OGTT, as well as heart and liver magnetic resonance imaging (MRI) T2*, was performed. For all statistical analyses, SPSS 21.0 was used and p < 0.05 was accepted as statistically significant.

RESULTS

FPG, FINS, and HOMA-IRI were significantly increased while HOMA-ISI decreased in the beta TM patients when compared with those in the control group. In patients with beta TM, 17 (14.41%) of patients had been diagnosed with diabetes, while 48 (40.68%) had both impaired fasting glucose and impaired glucose tolerance. HbA1c, GA, and fructosamine were increased according to the degree of abnormal glucose metabolism. Statistically significant differences were found in age, SF, and cardiac T2* between the abnormal and normal OGTT groups.

CONCLUSION

HbA1c may be used as a significant measure for monitoring glycemic levels in patients with beta TM. Furthermore, GA and fructosamine were alternative indicators of glucose status. Patients with heart iron deposition or an SF > 4000 μg/L were prone to abnormal glucose metabolism, so chelation therapy should be reinforced.

From general toxicology to DNA disruption: A safety assessment of Plinia cauliflora (Mart.) Kausel

ETHNOPHARMACOLOGICAL RELEVANCE

Plinia cauliflora (Mart.) Kausel (Myrtaceae) is popularly known as "jaboticaba" or "jaboticaba". The fruit is appreciated for both fresh consumption and the manufacture of jelly, juice, ice cream, fermented beverages, and liqueurs. The more widespread traditional use of the plant involves the treatment of diarrhea, which utilizes all parts of the plant, including the fruit peels.

AIM OF THE STUDY

We sought to elucidate possible risks of the administration of an ethanol-soluble fraction that was obtained from an infusion of P. cauliflora fruit peels (SEIPC). We performed a series of experiments to evaluate possible toxicity, in which we administered SEIPC orally both acutely and repeatedly for 28 days. We also evaluated possible endocrine-disruptive and genotoxic effects in eukaryotic cells. The possible mutagenic activity of SEIPC was evaluated using reverse mutation (Ames) assays.

MATERIALS AND METHODS

SEIPC was produced and chemically characterized by LC-DAD-MS. Acute toxicity and behavioral and physiological alterations were evaluated in the modified Irwin test. Respiratory rate, arterial blood gas, electrocardiography, respiratory rate, heart rate, and blood pressure were evaluated, and hematological, biochemical, and histopathological analyses were performed after 28 days of oral treatment. The comet assay, mammalian erythrocyte micronucleus test, uterotrophic test, Hershberger bioassay, and AMES test were performed using appropriate protocols.

RESULTS

From SEIPC, ellagic acid and derivatives, flavonols and anthocyanidins, as well as citric acid and gallic acid, were annotated by LC-DAD-MS. We did not observed any significant toxic effects after acute or prolonged SEIPC treatment. No endocrine-disruptive or mutagenic effects were observed.

CONCLUSIONS

The present study found that SEIPC did not cause any significant alterations of various corporeal systems, including cardiac electrical activity, body temperature, respiratory rate, and arterial pressure. No alterations of biochemical, hematological, or blood gas parameters were observed. SEIPC did not cause any perturbations of the endocrine system or mutagenic, cytotoxic, or genotoxic effects. These findings substantiate the safe clinical use of P. cauliflora.

Early development of decreased β-cell insulin secretion in children and adolescents with hemoglobin H disease and its relationship with levels of anemia

BACKGROUND

Diabetes mellitus (DM) associated with iron overload has been reported among adults with transfusion-dependent thalassemia and those with non-transfusion-dependent thalassemia (NTDT), especially in β-thalassemia disease. However, little is known about glucose metabolism and how early its dysregulation can develop in α-thalassemia hemoglobin H (Hb H) disease, which is one of the most common types of NTDT worldwide.

PROCEDURE

We prospectively calculated glucose metabolism index in 40 patients (aged 10-25 years) with Hb H disease. Glucose metabolism data were compared between patients with deletional versus nondeletional Hb H, and between patients with normal versus abnormal insulin secretion/sensitivity.

RESULTS

Despite normal glucose tolerance in all patients, 52.5% had abnormal insulinogenic index indicating decreased β-cell insulin secretion. Patients with functional hemoglobin < 8 g/dL had significantly higher percentages of abnormal insulinogenic index. There was no significant difference in abnormal insulinogenic index between deletional and nondeletional Hb H.

CONCLUSION

Decreased β-cell insulin secretion is highly prevalent among children and adolescents with Hb H disease, and it is associated with levels of functional anemia at baseline, but not with the type of Hb H disease. This result warrants heightened awareness among hematologists due to potentially increased risk of DM later in life.

Iron regulatory protein 2 deficiency may correlate with insulin resistance

Iron is known to be a crucial regulator of glucose, and several studies have demonstrated that iron overload is one of the risk factors for insulin resistance and diabetes; however, the mechanism has not yet been clarified. To investigate the effect of iron overload on glucose metabolism and the underlying mechanism, Irp2 knockout (Irp2^-/-) mice (endogenous iron overload model) were used. We found that Irp2^-/- mice exhibited hyperglycemia and iron overload in the liver and skeletal muscle. Increased MDA, decreased SOD levels, and increased cell apoptosis were also found in the liver and muscle of Irp2^-/- mice. Glucose concentrations were significantly higher in Irp2^-/- mice in insulin tolerance tests. However, early-phase insulin secretion was not altered in Irp2^-/- mice. The expression of hepatic IRS2 and muscle GLUT4 was declined in Irp2^-/- mice at both mRNA and protein levels when compared with those of wild-type control. In conclusions, Irp2^-/- mice showed hyperglycemia, which might due to insulin resistance rather than due to impaired insulin secretion.

Decrement in Cellular Iron and Reactive Oxygen Species, and Improvement of Insulin Secretion in a Pancreatic Cell Line Using Green Tea Extract

OBJECTIVES

We have investigated the efficacy of mono- and combined therapy with green tea extract (GTE) in mobilizing redox iron, scavenging reactive oxygen species (ROS), and improving insulin production in iron-loaded pancreatic cells.

METHODS

Rat insulinoma pancreatic β-cells were iron-loaded using culture medium supplemented with either fetal bovine serum or ferric ammonium citrate and treated with various doses of GTE for epigallocatechin-3-gallate (EGCG) equivalence and in combination with iron chelators. Cellular iron, ROS, and secretory insulin were measured.

RESULTS

The rat insulinoma pancreatic cells took up iron from fetal bovine serum more rapidly than ferric ammonium citrate. After treatment with GTE (0.23-2.29 μg EGCG equivalent), cellular levels of iron and ROS were dose dependently decreased. Importantly, secretory insulin levels were increased nearly 2.5-fold with 2.29 μg of EGCG equivalent GTE, indicating a recovery in insulin production.

CONCLUSIONS

Green tea EGCG ameliorated oxidative damage of iron-loaded β-cells by removing redox iron and free radicals and attenuating insulin production. The impact can result in the restoration of pancreatic functions and an increase in insulin production. Green tea extract exerts iron-chelating, free-radical scavenging, and pancreato-protective effects in the restoration of β-cell functions, all of which we believe can increase insulin production in diabetic β-thalassemia patients.

Growth and Endocrine Function in Tunisian Thalassemia Major Patients

β-thalassemia major (β–TM) is among the most common hereditary disorders imposing high expenses on health-care system worldwide. The patient’s survival is dependent on lifetime blood transfusion which leads to iron overload and its toxicity in various organs including endocrine glands. This article provides an overview of endocrine disorders in beta-TM patients. This single center investigation enrolled 28 β-TM patients (16 males, 12 females) regularly transfused with packed red cell since early years of life. For each patient were determined: age, sex, number of transfusions received, history of splenectomy and anthropometric parameters. All patients underwent an evaluation of hormonal status including growth, gonadal, thyroid, adrenal cortex, and parathyroid glands. Dual-energy X-ray absorptiometry was used to diagnose low bone mass. Assessment of iron overload status was performed by measuring the serum ferritin concentration and the results of magnetic resonance imaging T₂*. Growth retardation was found in 16 of the 28 studied patients (57 %). Thirteen among them had delayed puberty. Spontaneous puberty was achieved in 16 cases. Growth hormone (GH) deficiency was found in 10 cases (35 %). Seventeen among the studied patients (60 %) developed disorders of glucose homeostasis. Subclinical hypothyroidism was found in six patients (21 %). Intensive chelation therapy had allowed the reversibility of this complication in five cases. Adrenal Insufficiency was observed in 9 cases (32%). Hypoparathyroidism has occurred in one case. Ten of the 28 studied patients had low bone mass (35%). Twenty-three of the 28 studied patients (82%) had at least one endocrine complication.

Study of Insulin Resistance in Patients With β Thalassemia Major and Validity of Triglyceride Glucose (TYG) Index

Complications like impaired glucose tolerance and diabetes mellitus due to iron overload need early identification in thalassemia. We studied the proportion of insulin resistance in thalassemia major patients on chronic transfusion, identified insulin resistance using homeostasis model assessment of insulin resistance (HOMA-IR) and triglyceride glucose (TYG) index, compared them and validated TYG index. In total, 73 thalassemia patients on regular transfusion for 3 years with serum ferritin >1500 ng/mL were studied. Serum ferritin, fasting blood glucose, triglycerides, and insulin levels were measured, HOMA-IR, and TYG index calculated and analyzed. Mean fasting glucose, triglyceride, and serum insulin values were 104 mg/dL, 164.18 mg/dL, and 19.6 m IU/mL, respectively. Mean serum ferritin was 5156 ng/mL. Insulin resistance was prevalent in one third of thalassemia patients and showed increase with age and serum ferritin. Insulin resistance by HOMA-IR was 32% as against 16% by TYG index with a cut-off value of 4.3. Using receiver operating charecteristic curve analysis, it was found that, by lowering the value of TYG index to 4.0215, sensitivity improved to 78.3% (from 39.13%) with specificity of 70%. Hence, we recommend a newer lower cut-off value of 4.0215 for TYG index for better sensitivity and specificity in identifying insulin resistance.

A complicated disease: what can be done to manage thalassemia major more effectively?

Patients with thalassemia major suffer from many complications, but in the last two decades their lives have improved both in length and quality. We report herein the most common complications and the recent advances that have changed the course of this disease. Also, we report in detail some of the new therapeutic strategies already introduced in practice and briefly some that are still being developed.