[Effect of iron overload on experimental immunological liver injury in rats and the role of angiotensin]

OBJECTIVE

To investigate the effect of iron overload on experimental immunological liver injury in rats and the roles of losartan (LOS), which is the selective antagonist of angiotensin II receptor subtype AT1.

METHODS

Fifty male Wistar rats were divided by random into five groups (control, liver injury, liver injury + LOS, liver injury + ID and liver injury + ID + LOS). Immunological liver injury model was reproduceed by intravenous injection of BCG (Bacilli Calmette Guein) and then lipopolysaccharide (LPS). Iron overload model was created by intraperitoneal injection of iron dextran (ID). Serum iron (SI), transferrin (TRF), total protein (TP), the activity of asparatate aminotransferase (AST) and malondialdehyde (MDA) and liver iron (HIC) were tested. The expression of bcl-2 and Bax and the bax/bcl-2 ratio in hepatocyte were tested by flow cytometric analysis. Apoptotic index (AI) and proliferative index were also calculated.

RESULTS

(1) In comparison with blank control group, the activity of serum AST was higher. Serum TP and TRF were lower in liver injury animals. Liver MDA increased significantly and along with a lower SOD activity. The expression of Bax in liver injury group was significantly higher than that in control group. The bax/ bcl-2 ratio and AI increased significantly in liver injury group. (2) Compared with liver injury group, the animals treated with ID showed an increase of serum AST activity, increased MDA and the expression of bax, the bax/bcl-2 ratio and AI. HIC was higher than the control group. (3) Compared with liver injury group, the activity of serum AST was lower and TRF was higher, MDA was reduced and SOD activity increased in animals treated with LOS. The expression of bcl-2 was increased, bax/bcl-2 ratio and AI decreased in this group. (4) In comparison with ID treated liver injury animals, the activity of AST and the content of MDA, and TRF increased in the animals treated with ID plus LOS.

CONCLUSION

The immunological liver injury could be aggravated by iron overload through catalyzing lipid peroxidation and facilitating the apoptotic process of hepatocyte. Angiotensin faciliates in this kind of liver damage.

Growth and endocrine function in thalassemia major in childhood and adolescence

BACKGROUND

Thalassemia major is an inherited hemoglobin disorder characterized by chronic anemia and iron overload due to transfusion therapy and gastrointestinal absorption. Iron overload causes most of the associated mortality and morbidity and frequently involves the endocrine glands.

AIM

To review the most pertinent literature on the topic.

METHODS

One hundred and twenty-three papers were evaluated.

RESULTS

Disproportionate short stature is frequent and becomes more evident at puberty because of the lack of growth spurt. Later on, partial height recovery may occur. Long-term treatment with recombinant human GH seems ineffective to improve final height. Pubertal development is characterized by a clinical spectrum ranging from hypogonadism to a simple delay in starting and developing of puberty. Hormonal replacement is mandatory in cases of absent or arrested puberty. Pancreatic beta-cells function may be impaired during adolescence or later on. Its impairment ranges from hyperinsulinemia, secondary to insulin resistance, with normal glucose tolerance to beta-cells failure with insulin-dependent diabetes mellitus. Primary hypothyroidism may affect thalassemic patients from the second decade of life. The thyroid dysfunction may be reversible (if an intensive chelation therapy regimen is started in the precocious phase), stationary, or slowly progressive. Central hypothyroidism is less common and autoimmune thyroiditis absent.

CONCLUSION

Despite the improvement of the treatment, the involvement of the endocrine system still burdens the life of these patients. Further therapeutic improvement would reasonably reduce morbidity and, hopefully, mortality of thalassemic patients and make the endocrine disorders easier to treat.

Hepatitis C comorbidities affecting the course and response to therapy

Several studies have demonstrated that the outcome of chronic hepatitis C (CHC) infection is profoundly influenced by a variety of comorbidities. Many of these comorbidities have a significant influence on the response to antiviral therapy. These comorbidities negatively affect the course and outcome of liver disease, often reducing the chance of achieving a sustained virological response with PEGylated interferon and ribavirin treatments. Comorbidities affecting response to antiviral therapy reduce compliance and adherence to inadequate doses of therapy. The most important comorbidities affecting the course of CHC include hepatitis B virus coinfection, metabolic syndrome, and intestinal bacterial overgrowth. Comorbidities affecting the course and response to therapy include schistosomiasis, iron overload, alcohol abuse, and excessive smoking. Comorbidities affecting response to antiviral therapy include depression, anemia, cardiovascular disease, and renal failure.

[Effect of iron overload on function of pancreatic beta cells in rats]

This investigation was made to assess the effect of iron overload on function of pancreatic islet cells in Wistar rats. Sixty-five male rats were randomly divided into four groups: Group A received repeated intraperitoneal (i. p.) injections of ferric nitrilotriacetate (FeNTA); Group B received the equivalent dose of Na2 NTA; Group C received i. p. injection of Diethylenetriaminepentaacetic acid in addition to FeNTA; and Group D rats were untreated controls. Glucose tolerance tests were performed at the beginning, 5th week, and 10th week. Serum iron(SI) and serum ferritin (SF) were measured. The pancreatic tissues were taken for immunohistochemical exam; the levels of Insulin, Glucagon, ss in islets were also evaluated. At the 10th week, the levels of plasma glucose at 2 hours after glucose load in groups A and C were higher than those in groups B and D (P = 0.043); the granules of insulin in beta cells of group A were decreased obviously, the area of islets of group A was smaller than those of other groups (P = 0. 000). Iron overload might influence glycometabolism. And the beta cells' capability to secrete insulin was decreased obviously. Therefore, by way of removing iron, it is possible to protect the rat's glycometabolism to some extent.

Multislice multiecho T2* cardiac magnetic resonance for the detection of heterogeneous myocardial iron distribution in thalassaemia patients

The present study investigated myocardial T2* heterogeneity in thalassaemia major (TM) patients by cardiac magnetic resonance (CMR), to determine whether is related to inhomogeneous iron overload distribution. A total of 230 TM patients consecutively referred to our laboratory were studied retrospectively. Three short-axis views (basal, medium and apical) of the left ventricle (LV) were obtained by multislice multiecho T2* CMR. T2* segmental distribution was mapped on a 16-segment LV model. The level of heterogeneity of the T2* segmental distribution, evaluated by the coefficient of variation (CoV), was compared with that of a surrogate data set, to determine whether the inhomogeneous segmental distribution of T2* could be generated by susceptibility artefacts. Susceptibility artefacts offer an explanation for the T2* heterogeneity observed in patients without iron overload. In subjects with global T2* below the lower limit of the normal, T2* heterogeneity increased abruptly which could not be explained by artefactual effects. Some segmental T2* values were below and others above the limit of normal threshold (20 ms) in 104 (45%) TM patients. Among these patients, 74% showed a normal T2* global value. In conclusion, a true heterogeneity in the iron overload distribution may be present in TM patients. Heterogeneity seemingly appears in the borderline myocardial iron and stabilizes at moderate to severe iron burden.

Iron Burden and Liver Fibrosis Decrease During a Long-Term Phlebotomy Program and Iron Chelating Treatment After Bone Marrow Transplantation

In this retrospective study, we report the results of the association of a combined phlebotomy program and chelation in hereditary sideroblastic anemia (HSA) to reduce iron overload after bone marrow transplantation (BMT). A male HSA patient, not responding to pyridoxine treatment, was submitted to successful allogeneic BMT. As there was a persistence of a tissue iron overload, a regular phlebotomy program was started followed by chelation. A significant decrease of iron burden was obtained using a combined treatment with deferoxamine (DFO) and deferiprone (L1) in addition to the phlebotomy program. A 10-year follow-up shows a marked decrease in the concentration of serum ferritin, non-transferrin-bound iron (NTBI), liver iron and normal hemoglobin (Hb), which allows the patient to reach and maintain a good quality of life.

Glucose abnormalities in non-alcoholic fatty liver disease and chronic hepatitis C virus infection: the role of iron overload

Non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection are major causes of liver disease frequently described in outpatient patients with glucose abnormalities. Hyperferritinemia, which suggests that iron overload plays a decisive role in the pathophysiology of insulin resistance and hyperglycemia, is a common finding in both disorders. However, the role of the hepatic iron deposition differs from one to the other. In NAFLD, a moderate liver iron accumulation has been observed and molecular mechanisms, including the downregulation of the liver iron exporter ferroportin-1, have been described. Iron overload will enhance intrahepatic oxidative stress that promotes hepatic fibrosis, interfere with insulin signalling at various levels and may hamper hepatic insulin extraction. Therefore, liver fibrosis, hyperglycemia and hyperinsulinemia will lead to increased levels of insulin resistance and the development of glucose abnormalities. Furthermore, iron depletion by phlebotomy removes liver iron content and reduces serum glucose and insulin resistance in NAFLD patients. Therefore, it seems that iron overload participates in those glucose abnormalities associated with NAFLD. Concerning chronic HCV infection, it has been classically assumed that iron overload contributes to insulin resistance associated with virus infection. However, recent evidence argues against the presence of iron overload in these patients and points to inflammation associated with diabetes as the main contributor to the elevated ferritin levels. Therefore, glucose abnormalities, and specially type 2 diabetes, should be taken into account when evaluating serum ferritin levels in patients with HCV infection.

Association between porphyria cutanea tarda and beta-thalassemia major

The paper describes the first two cases of porphyria cutanea tarda associated with beta-thalassemia major. The clinical course of two female patients affected by beta-thalassemia major was complicated by the onset of porphyria cutanea tarda. Both patients were also suffering from hepatitis C virus infection, iron overload and anemia. We discuss about the role performed by some of these conditions in triggering overt porphyria cutanea tarda. An improvement of the clinical and biochemical picture of porphyria cutanea tarda in both patients was obtained with chloroquine therapy given that their chronic anemia did not permit phlebotomy.

Persistent atrial standstill and idioventricular rhythm in a patient with thalassemia intermedia

We present a 57-year old male patient with thalassemia intermedia and right heart failure. He had a 30-year history of anemia and short-term iron therapy without blood transfusion. Hemoglobin level was 7.1 g/dl and hematocrit was 22.7%. White blood-cell and platelet counts, and serum ferritin level were normal. Electrocardiography showed irregular narrow QRS bradyarrhythmia, suggesting slow atrial fibrillation at a mean rate of 35 beats/min. Echocardiographic examination revealed dilatation of the right atrium and ventricle, depressed systolic right ventricular function, advanced tricuspid regurgitation, and mild pericardial effusion. In the electrophysiologic study, no electrical activity was recorded in the right atrium. It was inexcitable at multiple sites and no retrograde conduction to the right atrium could be elicited by ventricular pacing. His bundle (HB) recording showed fixed retrograde HB activation with ventricular rhythm originating from different foci. Retrograde V-H conduction time during ventricular rhythm was 95 msec and did not change. There was no retrograde nodal conduction. A VVIR pacemaker was implanted. During a six-month follow-up, he felt well, his functional capacity was NYHA class II, and his basic rhythm was widened QRS arrhythmia with a rate of 20 beats/min. To the best of our knowledge, atrial electrical inactivity together with right-heart failure and pericarditis confined to the right heart chambers has hitherto not been reported in thalassemic disorders.

[Risk factors and prevention of retinopathy of prematurity]

The history of retinopathy of prematurity (ROP) gives a prime example of how dangerous the uncontrolled introduction of a new medical treatment--particularly in the field of neonatology--may be. The most important risk factors for the development of ROP are the immaturity of premature infants as well as uncontrolled and/or inadequate treatment with oxygen. In comparison to the fetus, the premature infant is exposed to a nonphysiologically high oxygen concentration. This hyperoxia leads to formation of aggressive oxygen radicals on the one hand and, on the other hand, to temporarily reduced production of growth factors such as vascular endothelial growth factor and erythropoietin, which both play an important role in the pathogenesis of ROP. The most important measure to prevent ROP is restrictive and carefully monitored oxygen treatment. Medical treatment to prevent ROP includes injection of D-penicillamine and retinol, but the available data are still limited, particularly with regard to the long-term effects of this treatment. A higher oxygenation in prethreshold ROP does not lead to recovery of ocular findings, but it increases the incidence of pulmonary complications. A reduction of light intensity in neonatal intensive care units proved not to be efficient for preventing ROP. To avoid blindness, standardized screening of the risk group is needed.

Evaluation of a web-based network for reproducible T2* MRI assessment of iron overload in thalassemia

PURPOSE

To build and evaluate a national network able to improve the care of thalassemia, a genetic disorder in haemoglobin synthesis often associated with iron accumulation in a variety of organs, due to the continuous blood transfusions.

METHODS

The MIOT (Myocardial Iron Overload in Thalassemia) network is constituted by thalassemia and magnetic resonance imaging (MRI) centers. Thalassemia centers are responsible for patient recruitment and collection of anamnestic and clinical data. MRI centers have been equipped with a standardized acquisition technique and an affordable workstation for image analysis. They are able to perform feasible and reproducible heart and liver iron overload assessments for a consistent number of thalassemia patients in a robust manner. All centers are linked by a web-based network, configured to collect and share patient data.

RESULTS

On 30th March 2008, 695 thalassemia patients were involved in the network. The completion percentage of the patient records in the database was 85+/-6.5%. Six hundred and thirteen patients (88%) successfully underwent MRI examination. Each MRI center had a specific absorption capacity that remained constant over time, but the network was capable of sustaining an increasing number of patients due to continuous enrollment of new centers. The patient's comfort, assessed as the mean distance from the patient home locations to the MRI centers, significantly increased during the network's evolution.

CONCLUSION

The MIOT network seems to be a robust and scalable system in which T2* MRI-based cardiac and liver iron overload assessment is available, accessible and reachable for a significant and increasing number of thalassemia patients in Italy (about 420 per year), reducing the mean distance from the patient locations to the MRI sites from 951km to 387km. A solid, wide and homogeneous database will constitute an important scientific resource, shortening the time scale for diagnostic, prognostic and therapeutical evidence-based research on the management of thalassemia disease.

Association of body iron stores with development of cardiovascular disease in the adult population: a systematic review of the literature

BACKGROUND AND OBJECTIVE

Studies have indicated divergent results on the relationship between body iron stores and cardiovascular disease in adults. This systematic review of the literature explored quantitative research studies in search for an understanding of the association between body iron stores and cardiovascular disease in adults over the age of 18 years with or without previously diagnosed cardiovascular disease.

METHODS

Articles were searched from 1992 to October 2008 using interlibrary loan, hand searching at the University of Windsor Leddy Library, and by using five electronic databases: Proquest, CINAHL, Medline, PubMed and AHA. The literature search resulted in 16 articles that were each read two times and interpreted by one reviewer.

RESULTS AND CONCLUSIONS

Serum iron and serum transferrin receptor were not found to increase the risk for cardiovascular disease. Only one study in the literature examined transferrin receptor to serum ferritin ratio and found it to be related to developing an initial acute myocardial infarction. Five studies found a significant association between serum ferritin and heart disease, while nine did not. Overall, there was no strong association in the literature between body iron stores and cardiovascular disease. The lack of consistent findings in the literature suggests the need for further research.

High nontransferrin bound iron levels and heart disease in thalassemia major

Although the presence of nontransferrin bound plasma iron (NTBI) in transfusional iron overload is well documented, knowledge about its clinical significance is limited. We assessed NTBI levels in a large and homogeneous series of thalassemia patients on regular transfusion and chelation and explored the hypothesis that NTBI levels may be associated with relevant clinical outcomes: in particular, heart disease. Among 174 patients with thalassemia major and intermedia, we showed the presence NTBI in 145 of 174 or 83.3% of cases. NTBI levels correlated with transferrin saturation, age, and ALT, and not with serum ferritin or liver iron concentrations. At a multiple regression analysis, transferrin saturation and heart disease but not age was independent predictors of NTBI. Patients with heart disease had NTBI levels significantly higher than those without. All patients with heart disease had transferrin saturation above 70%, and all were NTBI positive. Conversely, none of the patients without NTBI and/or with transferrin saturation less than 70% had preclinical or clinical heart disease. To our knowledge, this is the first documentation of a link between the presence of NTBI in thalassemic patients with transfusional iron overload and heart disease. Further investigation from these preliminary findings may clarify whether NTBI assessment may have a role in evaluating the risks and optimizing treatment for transfusion-dependent patients.

Iron and age-related macular degeneration

Iron can be involved in the pathogenesis of age-related macular degeneration (AMD) through the oxidative stress. In siderosis, exogenous iron can cause retinal degeneration which can be also associated with elevated retinal iron levels resulting in hereditary defects in iron homeostasis. Iron is transported into the retina by the endocytosis of iron complexed with transferrin and stored in complex with ferritin. The retinal pigmented epithelium and the neuroretinal vasculature serve as blood-retina barriers and disruption of homeostasis at these barriers may result in iron overload. There is firm experimental evidence that retinas of AMD patients contain more iron than retinas of the healthy subjects, but the question whether it is the reason or a consequence of AMD remains open. Excessive iron can cause damage to protein, lipids and DNA through the generation of free radicals in the Fenton reaction. Therefore, iron may play a role in the pathogenesis of AMD as a source of free radical damage but this hypothesis has not been verified experimentally and further studies are needed to establish the relationship between disturbance in iron homeostasis and AMD.

Regulation of iron absorption in hemoglobinopathies

Beta-thalassemia and sickle cell anemia (SCD) represent the most common hemoglobinopathies caused, respectively, by deficient production or alteration of the beta chain of hemoglobin (Hb). Patients affected by the most severe form of thalassemia suffer from profound anemia that requires chronic blood transfusions and chelation therapies to prevent iron overload. However, patients affected by beta-thalassemia intermedia, a milder form of the disease that does not require chronic blood transfusions, eventually also show elevated body iron content due to increased gastrointestinal iron absorption. Even SCD patients might require blood transfusions and iron chelation to prevent deleterious and painful vaso-occlusive crises and complications due to iron overload. Although definitive cures are presently available, such as bone marrow transplantation (BMT), or are in development, such as correction of the disease through hematopoietic stem cell beta-globin gene transfer, they are potentially hazardous procedures or too experimental to provide consistently safe and predictive clinical outcomes. Therefore, studies that aim to better understand the pathophysiology of the hemoglobinopathies might provide further insight and new drugs to dramatically improve the understanding and current treatment of these diseases. This review will describe how recent discoveries on iron metabolism and erythropoiesis could lead to new therapeutic strategies and better clinical care of these diseases, thereby yielding a much better quality of life for the patients.

Relationship between elevated liver enzyme with iron overload and viral hepatitis in thalassemia major patients in Northern Iran

OBJECTIVE

To determine the relationship between elevated liver enzymes with iron overload and viral hepatitis in thalassemic patients.

METHODS

This descriptive cross-sectional study was carried out in the thalassemic ward of Tonekabon Hospital, Mazandaran, Northern Iran from 20 April to 20 September of 2006. Patients were studied with respect to age, liver enzymes, anti-hepatitis C virus (anti-HCV) antibody, and hepatitis B surface antigen (HBsAg), transferrin saturation (TSAT), and blood transfusion index (multiplication of frequency and units of transfusion). Alanine aminotransferase (ALT) > or =40 U/L was considered elevated.

RESULTS

Sixty-five patients were evaluated (median age 19.51+/-8.9 years, range 4-54). Eleven patients were anti-HCV positive (16.9%). The mean serum ferritin was significantly higher in patients with ALT > or =40 (2553.08 ug/L versus 1783.7750 microg/L) (p=0.012). The mean ALT was significantly higher in patients with TSAT > or = 60% (41.26 U/L versus 28.82 U/L) (p=0.021). The relationship between ALT > or =40 and anti-HCV positivity was statistically significant. The mean ALT was 60.91 U/L in anti-HCV positive patients and 39.29 U/L in the negative group (p=0.001). The mean serum iron and transfusion index were significantly higher in anti-HCV positive versus negative patients (234.0 versus 195.4815; p=0.02), (1693.6 versus 1036.29, p=0.014).

CONCLUSION

Close association between elevated ALT with iron overload, transfusion index, age, and anti-HCV positivity in thalassemic patients of Tonekabon is recommended to re-evaluate transfusion and Desferal doses and therapies other than blood transfusion.

Porphyria cutanea tarda as a complication of therapy for chronic hepatitis C

There is a strong association between porphyria cutanea tarda (PCT) and chronic viral hepatitis C. Therapy for chronic viral hepatitis C may improve PCT. However, there are only a few reports of the de novo development of PCT during therapy for chronic viral hepatitis C. We describe the development of PCT in a 56-year-old patient with chronic viral hepatitis C after 12 wk of peginterferon/ribavirin therapy. In addition, the patient was homozygous for the H63D hereditary hemochromatosis gene (HFE) mutation. The association of PCT with chronic viral hepatitis C and the possible role of hepatic iron overload and ribavirin-induced hemolytic anemia in the development of PCT during therapy for chronic viral hepatitis C are discussed.

[Relationship between growth disorders and iron overload in children with beta-thalassemia major]

OBJECTIVE

To study the status of growth and development and the relationship between growth disorders and iron overload in children with beta-thalassemia major.

METHODS

Fifty children with beta-thalassemia major and who received blood transfusion therapy regularly (age: 9 months-17 years) were enrolled. They were subjected to a thorough history taking, clinical examinations, and laboratory examinations, including complete blood count, alanine transferasa (ALT) and serum ferritin. The physical growth parameters, such as height and weight, were compared with the reference values of Chinese children.

RESULTS

Twenty-four patients (48%) were of short stature with height under the 3th percentile. Among them, 15 cases presented with their height and weight both under the 3th percentile. Spontaneous sex development was seen in 7 cases out of 21 over 10-year-old patients. No sex development was found in 4 out of 8 patients who were over 14 years old. The patients with a height under the 10th percentile (n=31) had higher serum ferritin levels (8239.2+/-5865.5 mg/L vs 5028.1+/-3885.7 mg/L; P<0.05) and lower hemoglobin levels (68.2+/-12.3 g/L vs 79.7+/-14.5 g/L; P<0.05) as well as hepatomegaly when compared with those patients with a height over the 10th percentile (n=19). Serum ferritin levels in 20 patients with a weight under the 10th percentile were significantly higher than those in 30 patients with a height over the 10th percentile (9165.5+/-6042.5 mg/L vs 5567.3+/-4447.3 mg/L; P<0.05).

CONCLUSIONS

Short stature, low weight and sex development delay are common in children with beta-thalassemia major. This may be related to iron overload.

Inflammation in venous disease

Chronic venous disease (CVD), mainly due to venous reflux or, sometimes, to venous outflow obstruction, produces a microcirculatory overload leading to the impairment of venous drainage. Venous drainage depends primarily on a major hemodynamic parameter called trans-mural pressure (TMP). TMP is increased in patients affected by CVD, leading to impaired tissue drainage, and, consequently, facilitating the beginning of the inflammatory cascade. Increased TMP determines red blood cell extravasation and either dermal hemosiderin deposits or iron laden-phagocytes. Iron deposits are readily visible in the legs of all patients affected by severe CVD. Local iron overload could generate free radicals or activate a proteolytic hyperactivity of metalloproteinases (MMPs) and/or downregulate tissue inhibitors of MMPs. These negative effects are particularly evident in carriers of the common HFE gene's mutations C282Y and H63D, because intracellular iron deposits of mutated macrophages have less stability than those of the wild type, inducing a significant oxidative stress. It has been demonstrated that such genetic variants increase the risk of ulcers and advance the age of ulcer onset, respectively. The iron-dependent vision of inflammation in CVD paves the way to new therapeutic strategies including the deliberate induction of iron deficiency as a treatment modality for non-healing and/or recurrent venous leg ulcers. The inflammatory cascade in CVD shares several aspects with that activated in the course of multiple sclerosis, an inflammatory and neurodegenerative disease of unknown origin in which the impairment of cerebral venous outflow mechanisms has been recently demonstrated.

Iron chelation therapy in the myelodysplastic syndromes and aplastic anemia: a review of experience in South Korea

Emerging clinical data indicate that transfusion-dependent patients with bone marrow-failure syndromes (BMFS) are at risk of the consequences of iron overload, including progressive damage to hepatic, endocrine, and cardiac organs. Despite the availability of deferoxamine (DFO) in Korea since 1998, data from patients with myelodysplastic syndromes, aplastic anemia, and other BMFS show significant iron overload and damage to the heart and liver. The recent introduction of deferasirox, a once-daily, oral iron chelator, may improve the availability of iron chelation therapy to iron-overloaded patients, and improve compliance in patients who may otherwise find adherence to the DFO regimen difficult.