Correlation of Pancreatic Iron Overload Measured by T2*-Weighted Magnetic Resonance Imaging in Diabetic Patients with β-Thalassemia Major

Ferroptosis as a molecular target of epigallocatechin gallate in diseases

CONTEXT

Ferroptosis is a novel form of cell death characterised by iron overload and lipid peroxidation. It is closely associated with many diseases, including cardiovascular diseases, tumours, and neurological diseases. The use of natural chemicals to modulate ferroptosis is of great concern because of the critical role ferroptosis plays in disease. The main active ingredient in green tea is epigallocatechin gallate (EGCG), which is the most abundant catechin in green tea. EGCG shows a wide range of biological and therapeutic effects in various diseases, including anti-inflammatory, antioxidant, anticancer, and cardioprotective.

OBJECTIVE

The purpose of this article is to summarise the existing information on the relationship between EGCG and ferroptosis.

METHODS

Articles related to EGCG and ferroptosis were searched in PubMed and Web of Science databases, and the literature was analysed.

RESULTS AND CONCLUSION

EGCG could improve ferroptosis-related diseases and affect the development of ferroptosis by regulating the nuclear factor erythroid 2-related factor 2, autophagy, microRNA, signal transducer and activator of transcription 1, and protein kinase D1 signalling pathways.

T1 and T2-mapping in pancreatic MRI: Current evidence and future perspectives

Conventional T1- and T2-weighted magnetic resonance imaging (MRI) of the pancreas can vary significantly due to factors such as scanner differences and pulse sequence variations. This review explores T1 and T2 mapping techniques, modern MRI methods providing quantitative information about tissue relaxation times. Various T1 and T2 mapping pulse sequences are currently under investigation. Clinical and research applications of T1 and T2 mapping in the pancreas include their correlation with fibrosis, inflammation, and neoplasms. In chronic pancreatitis, T1 mapping and extracellular volume (ECV) quantification demonstrate potential as biomarkers, aiding in early diagnosis and classification. T1 mapping also shows promise in evaluating pancreatic exocrine function and detecting glucose metabolism disorders. T2* mapping is valuable in quantifying pancreatic iron, offering insights into conditions like thalassemia major. However, challenges persist, such as the lack of consensus on optimal sequences and normal values for healthy pancreas relaxometry. Large-scale studies are needed for validation, and improvements in mapping sequences are essential for widespread clinical integration. The future holds potential for mixed qualitative and quantitative models, extending the applications of relaxometry techniques to various pancreatic lesions and enhancing routine MRI protocols for pancreatic pathology diagnosis and prognosis.

Magnetic resonance imaging T2* of the pancreas value using an online software tool and correlate with T2* value of myocardium and liver among patients with transfusion-dependent thalassemia major

Objective

Patients with thalassemia major do require lifetime blood transfusions that eventually result in iron accumulation in different organs. We described the usefulness of using magnetic resonance imaging (MRI) T2^*imaging values for the evaluation of pancreatic iron load in these patients, and we correlated it with MRI T2^* haemosiderosis of the myocardium and liver that has been recognized as a non-invasive assessment of iron overload among patients with thalassemia major.

Materials and methods

We conducted a cross-sectional study on 39 patients with thalassemia major in one of the tertiary university hospitals for a 1-year period. Demographic data were collected from the patient's history. MRI T2^* of the pancreas, liver, and heart were executed on all patients in the same setting. Objective values of iron overload in these organs were obtained using the MRI post-processing software from online software.

Results

A total of 32 (82.1%) patients had pancreatic iron overload including 2 patients (5.1%) with severe iron overload and 15 patients (38.5%) with moderate and mild iron overload, respectively. Nine patients (23.1%) had myocardial iron overload, which included 3 patients (7.7%) who had severe cardiac haemosiderosis. Notably, 37 patients (94.9%) had liver iron overload, which included 15 patients (38.5%) who had severe liver haemosiderosis. There was a moderate positive correlation between the relaxation time of the pancreas and heart haemosiderosis (r = 0.504, P < 0.001). No significant correlation was found between the relaxation time of the pancreas with the liver and the heart with the liver.

Conclusion

Pancreatic haemosiderosis precedes cardiac haemosiderosis, which establishes a basis for initiating earlier iron chelation therapy to patients with thalassemia major.

The Close Link of Pancreatic Iron With Glucose Metabolism and With Cardiac Complications in Thalassemia Major: A Large, Multicenter Observational Study

OBJECTIVE

We systematically explored the link of pancreatic iron with glucose metabolism and with cardiac complications in a cohort of 1,079 patients with thalassemia major (TM) enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project.

RESEARCH DESIGN AND METHODS

MRI was used to quantify iron overload (T2* technique) and cardiac function (cine images) and to detect macroscopic myocardial fibrosis (late gadolinium enhancement technique). Glucose metabolism was assessed by the oral glucose tolerance test (OGTT).

RESULTS

Patients with normal glucose metabolism showed significantly higher global pancreas T2* values than patients with impaired fasting glucose, impaired glucose tolerance, and diabetes. A pancreas T2* <13.07 ms predicted an abnormal OGTT. A normal pancreas T2* value showed a 100% negative predictive value for disturbances of glucose metabolism and for cardiac iron. Patients with myocardial fibrosis showed significantly lower pancreas T2* values. Patients with cardiac complications had significantly lower pancreas T2* values. No patient with arrhythmias/heart failure had a normal global pancreas T2*.

CONCLUSIONS

Pancreatic iron is a powerful predictor not only for glucose metabolism but also for cardiac iron and complications, supporting the close link between pancreatic iron and heart disease and the need to intensify iron chelation therapy to prevent both alterations of glucose metabolism and cardiac iron accumulation.

Glucose dysregulation in patients with iron overload: is there a relationship with quantitative pancreas and liver iron and fat content measured by MRI?

OBJECTIVES

The aim was to investigate the relationship between pancreatic and hepatic iron and fat to glucose metabolism in patients with iron overload and address conflicting results in literature as regards the relationship between pancreas iron and glucose dysregulation.

METHODS

We retrospectively evaluated pancreatic and hepatic R2*, fat fraction (FF), liver iron concentration (LIC), and glucose metabolism in 105 patients with iron overload obtained with a multi-echo gradient echo R2* technique and assessed the correlation between pancreatic R2* and FF to glucose dysregulation.

RESULTS

There were no significant differences in pancreatic R2*, liver R2*, and FF in patients with iron overload and glucose dysregulation compared to those with normoglycemia (p = 0.435, p = 0.674, and p = 0.976), whereas pancreatic FF was significantly higher, 23.5% vs 16.7% respectively (p = 0.011). Pancreatic FF and R2* demonstrated an area under the curve of 0.666 and 0.571 for discriminating glucose dysregulation. Pancreatic FF of 26.2% yielded specificity and sensitivity of 80% and 45% for prediction of glucose dysregulation. Pancreatic R2* weakly correlated with pancreatic FF, r = 0.388 (p < 0.001), and liver R2*, r = 0.201 (p = 0.033), and showed no correlation with hepatic FF r = -0.013 (p = 0.892) or LIC categories (p = 0.493).

CONCLUSION

Pancreatic FF but not pancreatic R2* was associated with glucose dysregulation in patients with iron overload. Prior studies reporting correlation of pancreatic R2* to glucose dysregulation likely relate from inadequate MRI technique or analysis employed, which unlike our study did not perform simultaneous measurements of fat and iron essential to avoid their confounding effects during quantitative analysis.

KEY POINTS

• Pancreatic fat fraction, unlike iron, is associated with glucose dysregulation in iron overload. • Simultaneous measurement of pancreatic iron and fat content with MRI is essential to avoid confounding effects of one another during quantitative analysis. • Pancreatic fat fraction could be utilized to predict glucose dysregulation in iron overload states.

Brain iron content in systemic iron overload: A beta-thalassemia quantitative MRI study

•

Iron overload is a life-threatening condition in beta-thalassemia.

•

Data on brain involvement in systemic iron overload are conflicting.

•

MRI quantification of brain tissue iron content is feasible in a voxel-based approach.

•

No iron tissue excess is evident in beta-thalassemia but in the choroid plexuses.

Objective

Multisystem iron poisoning is a major concern for long-term beta-thalassemia management. Quantitative MRI-based techniques routinely show iron overload in heart, liver, endocrine glands and kidneys. However, data on the brain are conflicting and monitoring of brain iron content is still matter of debate.

Methods

This 3T-MRI study applied a well validated high-resolution whole-brain quantitative MRI assessment of iron content on 47 transfusion-dependent (mean-age: 36.9 ± 10.3 years, 63% females), 23 non-transfusion dependent (mean-age: 29.2 ± 11.7 years, 56% females) and 57 healthy controls (mean-age: 33.9 ± 10.8 years, 65% females). Clinical data, Wechsler Adult Intelligence Scale scores and treatment regimens were recorded. Beside whole-brain R2* analyses, regional R2*-values were extracted in putamen, globus pallidum, caudate nucleus, thalamus and red nucleus; hippocampal volumes were also determined.

Results

Regional analyses yielded no significant differences between patients and controls, except in those treated with deferiprone that showed lower R2*-values (p<0.05). Whole-brain analyses of R2*-maps revealed strong age-R2* correlations (r²=0.51) in both groups and clusters of significantly increased R2*-values in beta-thalassemia patients in the hippocampal formations and around the Luschka foramina; transfusion treatment was associated with additional R2* increase in dorsal thalami. Hippocampal formation R2*-values did not correlate with hippocampal volume; hippocampal volume did not differ between patients and controls. All regions with increased R2*-values shared a strict anatomical contiguity with choroid plexuses suggesting a blooming effect as the likely cause of R2* increase, in agreement with the available histopathologic literature evidence.

Conclusion

According to our MRI findings and the available histopathologic literature evidence, concerns about neural tissue iron overload in beta-thalassemia appear to be unjustified.

Quantitative pancreatic MRI: a pathology-based review

MRI plays an important role in the clinical management of pancreatic disorders and interpretation is reliant on qualitative assessment of anatomy. Conventional sequences capturing pancreatic structure can however be adapted to yield quantitative measures which provide more diagnostic information, with a view to increasing diagnostic accuracy, improving patient stratification, providing robust non-invasive outcome measures for therapeutic trials and ultimately personalizing patient care. In this review, we evaluate the use of established techniques such as secretin-enhanced MR cholangiopancreatography, diffusion-weighted imaging, T ₁, T ₂* and fat fraction mapping, but also more experimental methods such as MR elastography and arterial spin labelling, and their application to the assessment of diffuse pancreatic disease (including chronic, acute and autoimmune pancreatitis/IgG4 disease, metabolic disease and iron deposition disorders) and cystic/solid focal pancreatic masses. Finally, we explore some of the broader challenges to their implementation and future directions in this promising area.

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.

The improvement of pulmonary artery pressure after bosentan therapy in patients with β-thalassemia and Doppler-defined pulmonary arterial hypertension

Introduction

Pulmonary arterial hypertension (PAH) is relatively prevalent in patients with thalassemia. PAH treatment is necessary as the prevalence of Doppler-estimated PAH and the resultant mortality is high in such patients.

Materials and methods

This study aimed at evaluating the effect of bosentan therapy on patients with thalassemia suspected of PAH. Based on pulsed Doppler echocardiography, all the cases were suspected of severe PAH. Consequently, bosentan was initiated at a dose of 62.5 mg twice a day for 4 weeks, which was increased to 62.5–125 mg twice a day, if no adverse side effects were observed.

Results

The results of this study showed that pulmonary artery pressure (PAP) decreased after the administration of bosentan in three cases, from 160 to 120, 110 to 65, and 60 to 25 mmHg; in other words, the PAP reduced in the mentioned cases by 25%, 36.4%, and 58.4%, respectively.

Conclusion

In this study, PAP improved after bosentan therapy in patients with β-thalassemia suspected of PAH; however, further studies are required to confirm the findings.

Green tea extract modulates oxidative tissue injury in beta-thalassemic mice by chelation of redox iron and inhibition of lipid peroxidation

Iron overload in patients with β-thalassemia can cause oxidative organ dysfunction. Iron chelation along with antioxidant supplementation can ameliorate such complications and prolong lives. Green tea extract (GTE) rich in epigallocatechin-3-gallate (EGCG) exhibits anti-oxidation and iron chelation properties in β-knockout thalassemic (BKO) mice diagnosed with iron overload. We investigated the effects of GTE and deferiprone (DFP) alone in combination with one another, and upon the levels of redox-active iron, lipid-peroxidation product, insulin and hepcidin in BKO mice. A state of iron overload was induced in the mice via a trimethylhexanoyl-ferrocene supplemented (Fe) diet for 3 months, and the mice were treated daily with either: DFP (50 mg/kg), DFP (50 mg/kg) plus GTE (50 mg EGCG equivalent/kg), or GTE alone for 2 months. Plasma non-transferrin bound iron (NTBI), malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepcidin and insulin; tissue iron and MDA were measured. DFP, GTE and GTE + DFP effectively decreased plasma MDA (p < 0.05), NTBI and ALT, and increased plasma hepcidin and insulin. All the treatments also reduced iron accumulation and MDA production in both the pancreas and liver in the mice. However, the combination therapy demonstrated no advantages over monotherapy. The findings suggest GTE improved liver and pancreatic β-cell functions in iron-overloaded β-thalassemia mice by diminishing redox iron and free radicals, while inhibiting lipid peroxidation. Consequently, there are indications that GTE holds significant potential for clinical use.