The effects of vitamin E on platelet activity in β-thalassaemia patients

Comparative analysis of cold-stored apheresis platelet units in additive solution with or without pathogen reduction: Implications of cytochrome c supplementation

BACKGROUND

Platelets are limited in supply, and the preservation of platelet function during storage remains challenging. Novel storage approaches are being explored to improve platelet quality, extend shelf life, and reduce risk of infection. This study sought to elucidate platelet function in cold-stored apheresis units in additive solution (platelet additive solution [PAS]) and subjected to pathogen reduction (PR) as well as the impact of cytochrome c (cyt c) supplementation. We hypothesized that the PR would decrease stored platelet function, regardless of cyt c supplementation.

METHODS

Platelet apheresis units (PAS) were collected (N = 5 volunteers) and divided into PR or no PR (PAS) and supplemented with vehicle or cyt c (100 μM). Units were stored at 4°C for 15 days, sequential aliquots were removed, and platelet/mitochondrial respiratory function and biochemical parameters were analyzed.

RESULTS

There was no difference in platelet aggregation in response to adenosine diphosphate between PAS and PR platelets. Aggregation function in response to arachidonic acid was higher in PR versus PAS platelets. Maximum clot strength was not different between PAS and PR from Day 0 to Day 5 but declined in PR platelets on Days 10 and 15. Oxygen consumption declined at the same rate in PAS and PR platelets, while rate of lactate and TCO 2 decrease was greater in PR platelets than in PAS platelets. Supplementation with cyt c did not alter platelet function or biochemical parameters in PAS or PR platelets.

CONCLUSION

Platelet additive solution and PR platelets show similar declines in respiratory capacity, and biochemical parameters during cold storage, but PR platelets demonstrated significantly increased arachidonic acid-induced aggregation across all time points. Further understanding this mechanism may provide a means to prolong platelet shelf life.

Dyslipidemia and atherogenic indexes in children with transfusion-dependent thalassemia

OBJECTIVE

This study endeavored to assess the lipid profile and atherogenic lipid indexes in children with transfusion-dependent thalassemia (TDT) and to compare them with matched healthy children.

METHOD

The study group consisted of a total of 72 TDT patients aged 3 to14 years, while the control group had 83 age- and sex-matched healthy children. The fasting lipid profile and lipid indexes were estimated and the atherogenic index of plasma (AIP), Castelli's risk indexes I and II, atherogenic coefficient were calculated and compared between the two groups.

RESULT

Compared to the control group, the mean LDL, HDL and cholesterol levels were significantly lower among the case group (p-value < 0.001). The mean VLDL and triglycerides were significantly higher in the case group (p-value < 0.001). Lipid indexes, including the atherogenic index of plasma (AIP), Castelli's risk indexes I and II and atherogenic coefficients were significantly higher in TDT children.

CONCLUSION

Dyslipidemia and increased risk of atherosclerosis were found in TDT children, as they had elevated atherogenic lipid indexes. Our study underlines the importance of the routine use of these indexes in TDT children. Future studies should focus on lipid indexes in this high-lipid group of children so that preventive strategies can be planned accordingly.

Deferiprone, an iron chelator, alleviates platelet hyperactivity in patients with β-thalassaemia/HbE

Background

Hyperfunctional platelets play important roles in thromboembolism in patients with β-thalassaemia/ haemoglobin E (β-thal/HbE). Our previous study revealed ex vivo inhibitory effects of deferiprone on normal platelets. Herein, we aimed to investigate the in vivo effects on platelets in patients with β-thal/HbE.

Methods

A prospective, self-controlled clinical study on 30 patients with β-thal/HbE who had received therapeutic deferiprone (20.8-94.5 mg/kg/day) was conducted. The study included a 4-week washout period followed by 4 and 12 weeks of deferiprone treatment. Platelet aggregation was performed by a turbidimetric method. Levels of deferiprone and soluble platelet (sP)-selectin in serum were measured by high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) kit, respectively.

Results

The washout period significantly enhanced platelet hyperactivity both in patients who had undergone splenectomy and in those who had not. At 2 hours following the administration of a single dose of deferiprone, platelet sensitivity to ADP and arachidonic acid was significantly reduced. The inhibitory effects of deferiprone were gradually increased over the period of 4 and 12 weeks. Deferiprone also depressed sP-selectin levels, but the effect was stable over longer follow-up periods. Correlation analysis demonstrated the relationship between serum levels of deferiprone, sP-selectin, and platelet activities induced by ADP and arachidonic acid.

Conclusion

We first demonstrated the in vivo antiplatelet effect and benefit of short-term treatment of deferiprone in patients with β-thal/HbE. The impact on thrombotic outcomes deserves further study.

Nutrition in Thalassemia: A Systematic Review of Deficiency, Relations to Morbidity, and Supplementation Recommendations

BACKGROUND

Reports of nutritional deficiencies in patients with thalassemia (Thal) are common. Despite its importance, however, nutritionally focused research in Thal has been limited by inadequate sample size, inconsistent methodology, a lack of control comparisons, and few interventional trials. Due to these limitations, clinicians lack evidence-based nutrition recommendations to support clinical decision-making. This systematic review summarizes observed relationships between nutrition and morbidity in Thal published in the last 3 decades.

METHODS

PubMed, Web of Science, and Embase were screened for articles pertaining to nutrition in Thal using comprehensive search terms. Studies performed in humans, written in English, and published between 1990 and 2020 were included. Over 2100 manuscripts were identified, from which 97 were included.

RESULTS

Patients with Thal were most often deficient in vitamins A, C, D, selenium, and zinc. Prevalence of nutritional deficiency was positively correlated with age and iron overload. Evidence to support the role of vitamin D and zinc for bone health was observed; zinc was also found to improve glucose metabolism.

CONCLUSIONS

Due to the risk for multinutrient deficiency, nutritional status should be assessed annually in patients with Thal with prompt nutrient replacement when deficiency is detected. Routine supplementation with vitamin D and zinc is recommended.

Hemoglobin-bound platelets correlate with the increased platelet activity in hemoglobin E/β-thalassemia

INTRODUCTION

An increase in platelet activity is a contributing factor to vascular complications in hemoglobin E/β-thalassemia (HbE/β-thal). Plasma-free hemoglobin (Hb) increases in HbE/β-thal patients and correlates with platelet activation, but the levels of Hb-bound platelets have never been reported. In this study, we aimed to investigate the levels of Hb-bound platelets and its association with platelet activity in HbE/β-thal patients.

METHODS

Hb-bound platelets were measured by flow cytometry in 22 healthy subjects and 26 HbE/β-thal patients (16 nonsplenectomized and 10 splenectomized HbE/β-thal patients). Plasma Hb was measured by the chemiluminescence method based on the consumption of nitric oxide (NO) by Hb. Expression of P-selectin and activated glycoprotein (aGP) IIb/IIIa on platelets was measured by flow cytometry as a marker of platelet activity.

RESULTS

Both nonsplenectomized and splenectomized HbE/β-thal patients had higher levels of Hb-bound platelets and plasma Hb than healthy subjects. In vitro incubation of dialyzed Hb from patients with platelets of healthy subjects caused an increase in Hb-bound platelets, which was partially inhibited by anti-GPIbα antibody. Plasma Hb positively correlated with Hb-bound platelets. Platelet P-selectin expression at baseline and in response to adenosine diphosphate (ADP, 1 µM) stimulation was higher in nonsplenectomized and splenectomized HbE/β-thal patients than healthy subjects. The ADP-induced aGPIIb/IIIa expression on platelets was also higher in HbE/β-thal patients than healthy subjects. Hb-bound platelets correlated with baseline P-selectin expression and ADP-induced P-selectin expression.

CONCLUSION

HbE/β-thal patients have increased Hb-bound platelets, which is associated with increased baseline platelet activation and reactivity.

Al-hijamah (wet cupping therapy of prophetic medicine) significantly and safely reduces iron overload and oxidative stress in thalassemic children: a novel pilot study

BACKGROUND

Thalassemia is a major health problem due to iron overload, iron deposition and oxidative stress-induced tissue damage. Here, we introduce Al-hijamah (a minor surgical excretory procedure) as a novel percutaneous iron excretion therapy. Al-hijamah is a wet cupping therapy of prophetic medicine, and prophet Muhammad, peace be upon him, strongly recommended Al-hijamah, saying: "The best of your treatment is Al-hijamah".

AIM OF THE STUDY

Our study aimed at investigating the safety, iron chelation, pharmacological potentiation and oxidant clearance effects exerted by Al-hijamah to thalassemic children.

PATIENTS AND METHODS

Ethical committee's approval and patients' written agreement consents were obtained. We treated 20 thalassemic children (15 males and five females aged 9.07±4.26 years) with iron chelation therapy (ICT) plus Al-hijamah (using sterile disposable sets and in a complete aseptic environment) vs a control group treated with ICT only. This clinical trial was registered in the ClinicalTrial.gov registry under the name "Study of the Therapeutic Benefits of Al-hijamah in Children with Beta Thalassemia Major" (identifier no NCT 02761395) on 30 January 2016.

RESULTS

Al-hijamah was quite simple, safe, effective, tolerable (with no side effects) and time-saving procedure (30-60 minutes). A single session of Al-hijamah significantly reduced iron overload (P<0.001) in all thalassemic children. Al-hijamah significantly decreased serum ferritin by 25.22% (from 3,778.350±551.633 ng/mL to 2,825.300±558.94 ng/mL), significantly decreased oxidative stress by 68.69% (P<0.05; serum malondialdehyde dropped from 42.155±12.42 to 13.195±0.68 nmol/L), exerted pharmacological potentiation to ICT and significantly increased total antioxidant capacity (P<0.001) by 260.95% (from 13.195±0.68 nmol/L to 42.86±12.40 nmol/L through excreting reactive oxygen species). Moreover, therapeutic indices for evaluating Al-hijamah were promising.

CONCLUSION

Al-hijamah is a novel, safe, effective percutaneous iron excretion therapy through percutaneous iron excretion with minimal blood loss in agreement with the evidence-based Taibah mechanism. Al-hijamah is an effective outpatient hematological procedure that is safer than many pediatric procedures such as catheterization, hemofiltration and dialysis. Increasing the number of cups during Al-hijamah session or the number of sessions reduces iron overload more strongly. Medical practice of Al-hijamah is strongly recommended in hospitals.

HbE/β-Thalassemia and Oxidative Stress: The Key to Pathophysiological Mechanisms and Novel Therapeutics

SIGNIFICANCE

Oxidative stress and generation of free radicals are fundamental in initiating pathophysiological mechanisms leading to an inflammatory cascade resulting in high rates of morbidity and death from many inherited point mutation-derived hemoglobinopathies. Hemoglobin (Hb)E is the most common point mutation worldwide. The βE-globin gene is found in greatest frequency in Southeast Asia, including Thailand, Malaysia, Indonesia, Vietnam, Cambodia, and Laos. With the wave of worldwide migration, it is entering the gene pool of diverse populations with greater consequences than expected.

CRITICAL ISSUES

While HbE by itself presents as a mild anemia and a single gene for β-thalassemia is not serious, it remains unexplained why HbE/β-thalassemia (HbE/β-thal) is a grave disease with high morbidity and mortality. Patients often exhibit defective physical development, severe chronic anemia, and often die of cardiovascular disease and severe infections. Recent Advances: This article presents an overview of HbE/β-thal disease with an emphasis on new findings pointing to pathophysiological mechanisms derived from and initiated by the dysfunctional property of HbE as a reduced nitrite reductase concomitant with excess α-chains exacerbating unstable HbE, leading to a combination of nitric oxide imbalance, oxidative stress, and proinflammatory events.

FUTURE DIRECTIONS

Additionally, we present new therapeutic strategies that are based on the emerging molecular-level understanding of the pathophysiology of this and other hemoglobinopathies. These strategies are designed to short-circuit the inflammatory cascade leading to devastating chronic morbidity and fatal consequences. Antioxid. Redox Signal. 26, 794-813.

Association of Iron Overload with Oxidative Stress, Hepatic Damage and Dyslipidemia in Transfusion-Dependent β-Thalassemia/HbE Patients

Blood transfusion can be a life-saving therapy for β-thalassemia major and β-thalassemia/HbE (β-TM) patients with chronic anemia, major caused severe iron overload particularly in β-TM patients received only blood transfusion therapy. We aim to evaluate the association of iron overload with oxidative stress, liver damage, and elevated very low density lipoprotein cholesterol (VLDL-C) in transfusion-dependent β-TM patients. Serum ferritin, malondialdehyde (MDA), liver profiles, triglycerides levels, and VLDL-C were significantly higher while total cholesterol, low-density lipoprotein cholesterol, high density lipoprotein cholesterol and total antioxidant capacity were lower in β-TM than controls. Serum ferritin was significantly correlated with MDA, liver enzymes and lipid profiles (p < 0.05). Multiple forward stepwise linear regression analyses of the significant variables showed that in these β-TM patients, independent predictors of iron overload were MDA (β = 0.410, r (2) = 0.671, p < 0.001), ALT (β = 0.493, r (2) = 0.578, p < 0.001), and VLDL-C (β = 0.253, r (2) = 0.711, p < 0.001). In conclusion, iron overload associated with increased oxidative stress, lipid peroxidation, liver damage, decreased TC, LDL-C, HDL-C and over production of VLDL-C, is significantly problem in transfusion-dependent β-TM patients. These appeared the major cause of future morbidity and mortality in β-TM patients.

Protein antioxidants in thalassemia

It is common knowledge that thalassemic patients are under significant oxidative stress. Chronic hemolysis, frequent blood transfusion, and increased intestinal absorption of iron are the main factors that result in iron overload with its subsequent pathophysiologic complications. Iron overload frequently associates with the generation of redox-reactive labile iron, which in turn promotes the production of other reactive oxygen species (ROS). If not neutralized, uncontrolled production of ROS often leads to damage of various intra- and extracellular components such as DNA, proteins, lipids, and small antioxidant molecules among others. A number of endogenous and exogenous defense mechanisms can neutralize and counteract the damaging effects of labile iron and the reactive substances associated with it. Endogenous antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, and ferroxidase, may directly or sequentially terminate the activities of ROS. Nonenzymatic endogenous defense mechanisms include metal binding proteins (ceruloplasmin, haptoglobin, albumin, and others) and endogenously produced free radical scavengers (glutathione (GSH), ubiquinols, and uric acid). Exogenous agents that are known to function as antioxidants (vitamins C and E, selenium, and zinc) are mostly diet-derived. In this review, we explore recent findings related to various antioxidative mechanisms operative in thalassemic patients with special emphasis on protein antioxidants.

Antioxidant vitamins C and E supplementation increases markers of haemolysis in sickle cell anaemia patients: a randomized, double-blind, placebo-controlled trial

Erythrocytes from sickle cell anaemia (SCA) patients continuously produce larger amounts of pro-oxidants than normal cells. Oxidative stress seems to primarily affect the membrane and results in haemolysis. The use of antioxidants in vitro reduces the generation of pro-oxidants. To evaluate the impact of vitamins C (VitC) and E (VitE) supplementation in SCA patients, patients over 18 years were randomly assigned to receive VitC 1400 mg + VitE 800 mg per day or placebo orally for 180 d. Eighty-three patients were enrolled (44 vitamins, 39 placebo), median age 27 (18-68) years, 64% female. There were no significant differences between the two groups regarding clinical complications or baseline laboratorial tests. Sixty percent of the patients were VitC deficient, 70% were VitE deficient. Supplementation significantly increased serum VitC and E. However, no significant changes in haemoglobin levels were observed, and, unexpectedly, there was a significant increase in haemolytic markers with vitamin supplementation. In conclusion, VitC + VitE supplementation did not improve anaemia and, surprisingly, increased markers of haemolysis in patients with SCA and S-β(0) -thalassaemia. The exact mechanisms to explain this findings and their clinical significance remain to be determined.

Oxidative modification and poor protective activity of HDL on LDL oxidation in thalassemia

Oxidative modification of low-density lipoprotein (LDL) has been reported in thalassemia, which is a consequence of oxidative stress. However, the levels of oxidized high-density lipoprotein (HDL) in thalassemia have not been evaluated and it is unclear whether HDL oxidation may be linked to LDL oxidation. In this study, the levels of total cholesterol, iron, protein, conjugated diene (CD), lipid hydroperoxide (LOOH), and thiobarbituric acid reactive substances (TBARs) were determined in HDL from healthy volunteers and patients with beta-thalassemia intermedia with hemoglobin E (beta-thal/Hb E). The protective activity of thalassemic HDL on LDL oxidation was also investigated. The iron content of HDL(2) and HDL(3) from beta-thal/HbE patients was higher while the cholesterol content was lower than those in healthy volunteers. Thalassemic HDL(2) and HDL(3) had increased levels of lipid peroxidation markers i.e., conjugated diene, LOOH, and TBARs. Thalassemic HDL had lower peroxidase activity than control HDL and was unable to protect LDL from oxidation induced by CuSO(4). Our findings highlight the oxidative modification and poor protective activity of thalassemic HDL on LDL oxidation which may contribute to cardiovascular complications in thalassemia.

Antifibrotic effects of tocotrienols on human Tenon's fibroblasts

PURPOSE

To compare the antifibrotic effect of vitamin E isoforms alpha-, gamma-, and delta-tocotrienol on human Tenon's fibroblasts (hTf) to the antimetabolite mitomycin C.

METHODS

Antifibrotic effects of alpha- (40, 60, 80, 100, and 120 microM), gamma- (10, 20, 30, and 40 microM) and delta-tocotrienol (10, 20, 30, and 40 microM) on hTf cultures were evaluated by performing proliferation, migration and collagen synthesis assays. Whereas for vitamin E the exposure time was set to 7 days to mimic subconjunctival application, cultures were exposed only 5 min to mitomycin C 100 microg/ml to mimic intraoperative administration. Cell morphology (phase contrast microscopy) as an assessment for cytotoxicity and cell density by measuring DNA content in a fluorometric assay to determine proliferation inhibition was performed on day 0, 4, and 7. Migration ability and collagen synthesis of fibroblasts were measured.

RESULTS

All tested tocotrienol isoforms were able to significantly inhibit hTf proliferation in a dose-dependent manner (maximal inhibitory effect without relevant morphological changes at day 4 for alpha-tocotrienol 80 microM with 36.7% and at day 7 for alpha-tocotrienol 80 microM with 42.6% compared to control). Degenerative cell changes were observed in cultures with concentrations above 80 microM for alpha- and above 30 microM for gamma- and delta-tocotrienol. The highest collagen synthesis inhibition has been found with 80 microM alpha-tocotrienol (62.4%) and no significant inhibition for mitomycin C (2.5%). Migration ability was significantly reduced in cultures exposed to 80 microM alpha- and 30 microM gamma-tocotrienol (inhibition of 82.2% and 79.5%, respectively, compared to control) and also after mitomycin C treatment (60.0%). Complete growth inhibition without significant degenerative cell changes could only be achieved with mitomycin C.

CONCLUSION

In vitro, all tested tocotrienol isoforms were able to inhibit proliferation, migration and collagen synthesis of human Tenon's fibroblasts and therefore may have the potential as an anti-scarring agent in filtrating glaucoma surgery.

Platelet aggregation and activation in thalassemia major patients in Indonesia

Thromboembolic events and hypercoagulable state have been reported in patients with thalassemia. As platelets play an important role in the pathogenesis of thrombosis, the authors aimed to find the pattern of changes in platelet count, function and activation, and evidence of coagulation activation in patients with thalassemia major in Indonesia. A total of 31 patients with splenectomized and 35 patients with nonsplenectomized thalassemia major were enrolled in this study. Platelet count, platelet aggregation, beta-thromboglobulin, and D-dimer levels were measured. All measured parameters were significantly higher in splenectomized than in nonsplenectomized patients. beta-thromboglobulin level was increased, but D-dimer level was within normal range. The authors concluded that there was an increase in platelet activation in patients with beta-thalassemia major. Platelet activation was higher in splenectomized than in nonsplenectomized patients.

Lipid fluidity at different regions in LDL and HDL of β-thalassemia/Hb E patients

Atherosclerosis-related vascular complications in beta-thalassemia/hemoglobin E (beta-thal/Hb E) patients may result from iron induced oxidation of lipoproteins. To identify the specific site of oxidative damage, changes in lipid fluidity at different regions in LDL and HDL particle were investigated using two fluorescence probes and two ESR spin probes. The magnitude of increased lipid fluidity in thalassemic lipoproteins was dependent on the location of the probes. In hydrophobic region, the rotational correlation times for 16-doxyl stearic acid and DPH anisotropy were markedly changed in LDL and HDL of the patients. In the surface region, there was only a slight change in the order parameter (S) for 5-doxyl stearic acid and TMA-DPH anisotropy. Lipid fluidity at the core of LDL and HDL showed good correlation with oxidative stress markers, the ratio of CL/CO, and the level of alpha-tocopherol, suggesting that hydrophobic region of thalassemic lipoprotein was a target site for oxidative damage.

Changing Patterns of Thalassemia Worldwide

Thalassemia is a growing global public health problem with an estimated 900,000 births of clinically significant thalassemia disorders expected to occur in the next 20 years. This growth will occur in disorders previously uncommon in many parts of the world. In particular, hemoglobin (Hb) E-beta-thalassemia and Hb H disease account for much of the projected increases in thalassemia. Worldwide, Hb E-beta-thalassemia is one of the most frequent hemoglobinopathies. The incidence of Hb E approaches 60% of the populations in many regions of Southeast Asia. In coastal regions of North America, its prevalence is rapidly growing. The severity of Hb E-beta-thalassemia ranges from a complete lack of symptoms to transfusion dependence. alpha-Thalassemia diseases, often considered benign, are now recognized to be more severe than originally reported. Hb H, Hb H-Constant Spring (CS), and homozygous alpha-thalassemia affect at least a million people worldwide. California considers Hb H disease a public health problem and has initiated a neonatal screening program for Hb H and particularly Hb H-CS. Homozygous alpha-thalassemia, usually fatal, is also being more commonly detected. Several regions have initiated universal prenatal screening programs to address homozygous alpha-thalassemia. In summary, the prognosis for thalassemia disorders is improving, but prenatal diagnosis and neonatal screenings are needed. Comprehensive services that address language and social barriers as well as access to Hb F-enhancing agents and transfusions are needed.

Quantitative evaluation of oxidative stress status on peripheral blood in beta-thalassaemic patients by means of electron paramagnetic resonance spectroscopy

High oxidative stress status (OSS) is known to be one of the most important factors determining cell injury and consequent organ damage in thalassaemic patients with secondary iron overload. Using an innovative hydroxylamine 'radical probe' capable of efficiently trapping majority of oxygen-radicals including superoxide we measured, by electron paramagnetic resonance (EPR) spectroscopy, OSS in peripheral blood of 38 thalassaemic patients compared with sex-/age-matched healthy controls. Thalassaemic patients showed sixfold higher EPR values of OSS than controls. Significantly higher EPR values of OSS were observed in those with a severe phenotype (thalassaemia major, transfusion-dependent) with respect to mild phenotype (sickle-cell/beta-thalassaemia, not transfusion-dependent) or thalassaemia intermedia. In patients with thalassaemia major, EPR values of OSS were positively correlated with serum ferritin and with alanine aminotransferase levels. In patients with sickle cell/beta-thalassaemia, there was no correlation between EPR value of OSS and all parameters considered. The type of chelating therapy (desferrioxamine or deferiprone) did not have an effect on EPR value of OSS. In conclusion, EPR 'radical probe' seems to be a valid innovative method to determine total OSS in patients affected by thalassaemia and might be used for evaluating new strategies of chelation, new chelators, or the efficacy of antioxidant formula.

Tocotrienol inhibits proliferation of human Tenon's fibroblasts in vitro: a comparative study with vitamin E forms and mitomycin C

PURPOSE

To evaluate the potential of the vitamin E compound alpha-tocotrienol as antifibrotic agent in vitro.

METHODS

Using human Tenon's capsule fibroblast cultures, the antiproliferative and cytotoxic effects of the different vitamin E forms alpha-tocopherol, alpha-tocopheryl acetate, alpha-tocopheryl succinate and alpha-tocotrienol were compared with those of mitomycin C. To mimic subconjunctival and regular oral application in vivo, exposure time of serum-stimulated and serum-restimulated fibroblasts (SF and RF, respectively) to vitamin E forms was set at 6 days. Cultures were only exposed for 5 min to mitomycin C due to its known acute toxicity and to mimic the short-time intraoperative administration. Proliferation (expressed as % of control) was determined by DNA content quantification on days 2, 4 and 6, whereas cytotoxicity was assessed by cell morphology and glucose 6-phosphate dehydrogenase (G6PD) release after 24 h.

RESULTS

alpha-Tocopherol and alpha-tocopheryl acetate stimulated growth of SF, but not RF. Reduction of fibroblast content by alpha-tocopheryl succinate was accompanied by increased G6PD release and necrosis. Contrary to alpha-tocopheryl succinate, 50 microM or repeatedly 20 microM of alpha-tocotrienol significantly inhibited proliferation without causing cellular toxicity (maximal effect: 46.8%). RF were more sensitive to this effect than SF. Mitomycin C 100-400 microg/ml showed a stronger antiproliferative effect than alpha-tocotrienol (maximal effect: 13.8%). Morphologic characteristics of apoptosis were more commonly found under treatment with mitomycin C.

CONCLUSIONS

Of the vitamin E forms tested, only alpha-tocotrienol significantly inhibited growth at non-toxic concentrations. In this in vitro study, antiproliferative effects of mitomycin C were stronger than those of alpha-tocotrienol.

Administration of ANG II induces iron deposition and upregulation of TGF-β1 mRNA in the rat liver

We previously found that ANG II infusion into rats causes iron deposition in the kidney and heart, which may have a role in the regulation of profibrotic gene expression and tissue fibrosis. In the present study, we have investigated whether ANG II can also induce iron accumulation in the liver. Prussian blue staining detected frequent iron deposition in the interstitium of the liver of rats treated with pressor dose ANG II for 7 days, whereas iron deposition was absent in the livers of control rats. Immunohistochemical and histological analyses showed that some iron-positive nonparenchymal cells were positive for ferritin and heme oxygenase-1 (HO-1) protein and TGF-β1 mRNA and were judged to be monocytes/macrophages. It was shown that ANG II infusion caused about a fourfold increase in ferritin and HO-1 protein expression by Western blot analysis and about a twofold increase in TGF-β1 mRNA expression by Northern blot analysis, which were both suppressed by treating ANG II-infused rats with losartan and deferoxamine. In addition, mild interstitial fibrosis was observed in the liver of rats that had been treated with pressor dose ANG II for 7 days or with nonpressor dose ANG II for 30 days, the latter of which also caused loss of hepatocytes and intrahepatic hemorrhage in the liver. Taken together, our data suggest that ANG II infusion induces aberrant iron homeostasis in the liver, which may have a role in the ANG II-induced upregulation of profibrotic gene expression in the liver.

Thalassemia

New developments in the epidemiology, treatment and prognosis of thalassemia have dramatically altered the approach to the care of affected patients, and these developments are likely to have an even greater impact in the next few years. Demographic changes have required an awareness and understanding of the unique features of thalassemia disorders that were previously uncommon in North America but are now seen more frequently in children and recognized more consistently in adults. New methods for measuring tissue iron accumulation and new drugs to remove excessive iron are advancing two of the most challenging areas in the management of thalassemia as well as other transfusion-dependent disorders. Improved survival of patients with thalassemia has given new importance to adult complications such as endocrinopathies and hepatitis that have a major impact on the quality of life. This chapter describes how these changes are redefining the clinical management of thalassemia.

In Section I, Dr. Renzo Galanello describes recent advances in iron chelation therapy. Several new chelators are either licensed in some countries, are in clinical trials or are in the late stages of preclinical development. Some of these iron chelators, such as deferiprone (DFP) and ICL670, are orally active. Others, such as hydroxybenzyl-ethylenediamine-diacetic acid (HBED) and starch deferoxamine, require parenteral administration but may be effective with less frequent administration than is currently required for deferoxamine. Chelation therapy employing two chelators offers the possibility of more effective removal of iron without compromising safety or compliance. Other strategies for chelation therapy may take advantage of the ability of particular chelators to remove iron from specific target organs such as the heart and the liver.

In Section II, Dr. Dudley Pennell addresses cardiac iron overload, the most frequent cause of death from chronic transfusion therapy. The cardiac complications related to excessive iron may result from long-term iron deposition in vulnerable areas or may be due to the more immediate effects of nontransferrin-bound iron. Cardiac disease is reversible in some patients with intensive iron chelation therapy, but identification of cardiac problems prior to the onset of serious arrhythmias or congestive heart failure has proven difficult. New methods using magnetic resonance imaging (MRI) have recently been developed to assess cardiac iron loading, and studies suggest a clinically useful relationship between the results using these techniques and critical measures of cardiac function. Measurements such as T2* may help guide chelation therapy in individual patients and may also enhance the assessment of new chelators in clinical trials. The use of MRI-based technology also holds promise for wider application of non-invasive assessment of cardiac iron in the management of patients with thalassemia.

In Section III, Dr. Melody Cunningham describes some of the important complications of thalassemia that are emerging as patients survive into adulthood. Hepatitis C infection is present in the majority of patients older than 25 years. However, antiviral therapy in patients with thalassemia has been held back by the absence of large clinical trials and concern about ribavirin-induced hemolysis. More aggressive approaches to the treatment of hepatitis C may be particularly valuable because of the additive risks for cirrhosis and hepatocellular carcinoma that are posed by infection and iron overload. Thrombosis is recognized with increasing frequency as a significant complication of thalassemia major and thalassemia intermedia, and pulmonary hypertension is now the focus of intense study. Risk factors for thrombosis such as splenectomy are being identified and new approaches to anticoagulation are being initiated. Pregnancies in women with thalassemia are increasingly common with and without hormonal therapy, and require a better understanding of the risks of iron overload and cardiac disease in the mother and exposure of the fetus to iron chelators.

In Section IV, Dr. Elliott Vichinsky describes the dramatic changes in the epidemiology of thalassemia in North America. Hemoglobin E-β thalassemia is seen with increasing frequency and poses a particular challenge because of the wide variability in clinical severity. Some affected patients may require little or no intervention, while others need chronic transfusion therapy and may be appropriate candidates for hematopoietic stem cell transplantation. Enhancers of fetal hemoglobin production may have a unique role in Hb E-β thalassemia since a modest increase in hemoglobin level may confer substantial clinical benefits. Alpha thalassemia is also being recognized with increasing frequency in North America, and newborn screening for Hemoglobin Barts in some states is leading to early detection of Hb H disease and Hb H Constant Spring. New data clarify the importance of distinguishing these two disorders because of the increased severity associated with Hb H Constant Spring. The use of intrauterine transfusions to sustain the viability of fetuses with homozygous alpha thalassemia has created a new population of patients with severe thalassemia and has raised new and complex issues in genetic counseling for parents with alpha thalassemia trait.