Transfusion related iron overload

Transfusion related iron overload

June-Won Cheong, M.D., Ph.D.

Dept. of Int. Med., Yonsei University College of Medicine

1.Iron metabolism

2.Transfusional iron overload 3.Measurement of body iron

4.Treatment for iron overload 5.National data

Contents

Iron Overloader

1.Iron metabolism

2.Transfusional iron overload 3.Measurement of body iron

4.Treatment for iron overload 5.National data

Contents

Ferrum, Iron

Fe ^2- Fe ^1- Fe

Fe ¹⁺ Fe ²⁺ Fe ³⁺ Fe ⁴⁺ Fe ⁵⁺ Fe ⁶⁺

Where?

Heme proteins

• Hemoglobin, Myoglobin, Cytochrome P450, etc

Other Metalloproteins

• Ferritin, Transferrin, Rubredoxin, etc

Other enzymes

• Catalase, Lipoxygenase,

Iron-responsive element-binding protein, etc

Free iron (Non-Transferrin-Bound Iron, NTBI)/Free radical

Where?

Heme proteins

• Hemoglobin, Myoglobin, Cytochrome P450, etc

Other Metalloproteins

• Ferritin, Transferrin, Rubredoxin, etc

Other enzymes

• Catalase, Lipoxygenase,

Iron-responsive element-binding protein, etc

Free iron (Non-Transferrin-Bound Iron, NTBI)/Free radical

Where?

Heme proteins

• Hemoglobin, Myoglobin, Cytochrome P450, etc

Other Metalloproteins

• Ferritin, Transferrin, Rubredoxin, etc

Other enzymes

• Catalase, Lipoxygenase,

Iron-responsive element-binding protein, etc

Free iron (Non-Transferrin-Bound Iron, NTBI)/Free radical

Where?

Heme proteins

• Hemoglobin, Myoglobin, Cytochrome P450, etc

Other Metalloproteins

• Ferritin, Transferrin, Rubredoxin, etc

Other enzymes

• Catalase, Lipoxygenase,

Iron-responsive element-binding protein, etc

Free iron (Non-Transferrin-Bound Iron, NTBI)/Free radical

Heme iron

Non-Heme iron

Where?

음식을 통해 섭취된 철이 흡수되는 곳은?

1.Stomach

2.Duodenum 3.Ileum

4.Jejunum 5.Colon

Where?

Andrews NC. Nat Gene Rev. 2000

In ^& Out Duodenal Enterocyte

DMT

In ^& Out Duodenal Enterocyte

HR

DMT

Ferritin

In ^& Out Duodenal Enterocyte

HR

DMT Ferroportin

Ferritin

In ^& Out Duodenal Enterocyte

HR

DMT Ferroportin

Ferritin

In ^& Out Duodenal Enterocyte

HR

DMT Ferroportin

Ferritin

In ^& Out Duodenal Enterocyte

Tf

DMT

Tf TFR

In ^& Out Erythroid Precursor

DMT

Ferroportin

Tf TFR

Ferritin

In ^& Out ^Hepatocyte

Tf

DMT

Ferroportin

Ferritin

In ^& Out ^Macrophage

Tf

DMT

DMT

Ferroportin

Tf TFR

1

2

3

1

Ferritin

In ^& Out

Tf

Summary

HR

DMT

DMT

Ferroportin

Tf TFR

Ferritin

In ^& Out

Hepcidin

Regulation

Iron overload Inflammation

Anemia Hypoxia

HR

HR

Iron Imbalance

Overload Deficiency

Hemochromatosis Transfusion...

Bleeding Hemolysis

Malabsorption...

1.Iron metabolism

2.Transfusional iron overload 3.Measurement of body iron

4.Treatment for iron overload 5.National data

Contents

Transfusional Iron Overload

In 2 units of Packed RBC

• ~ 400 mg of elementary iron

Clinically relevant iron overload

• as early as after 20 units of pRBC

• s-ferritin > 1,000~2,000 ng/ml

Guideline

Transfusion status s-Ferritin level

(μg/L)

MDS Pt profile

NCCN,

2014

• 20~30 pRBC Tf

• Will continue to receive Tf > 2,500

• IPSS Low or Int-1

Italian Society of Hematology,

2010

> 20 pRBC

• IPSS Low or Int-1

• IPSS Int-2 or High, responding to life- extending therapies or undergoing HSCT

MDS Consensus Statement

Nagasaki, 2005

Tf-dependent > 1,000~2,000

• IPSS Low or Int-1

• WHO RA, RARS and del(5q)

UK MDS Guidelines,

2003

~25 nRBC (5g)

• Pure sideroblastic

anemia

• del(5q)

Guidelines for Transfusional Iron Overload

Guideline

Transfusion status s-Ferritin level

(μg/L)

MDS Pt profile

NCCN,

2014

• 20~30 pRBC Tf

• Will continue to receive Tf > 2,500

• IPSS Low or Int-1

Italian Society of Hematology,

2010

> 20 pRBC

• IPSS Low or Int-1

• IPSS Int-2 or High, responding to life- extending therapies or undergoing HSCT

MDS Consensus Statement

Nagasaki, 2005

Tf-dependent > 1,000~2,000

• IPSS Low or Int-1

• WHO RA, RARS and del(5q)

UK MDS Guidelines,

2003

~25 nRBC (5g)

• Pure sideroblastic

anemia

• del(5q)

Guidelines for Transfusional Iron Overload

DMT

Ferroportin

Ferritin

Tf

What happen?

More

Transfusion

DMT

Ferroportin

Ferritin

Tf Tf Tf Tf

Tf

Tf

What happen?

More

Transfusion

DMT

Ferroportin

Ferritin

Tf Tf Tf Tf

Tf

Tf

What happen?

More

Transfusion

DMT

Ferroportin

Ferritin

Tf Tf Tf Tf

Tf

Tf

What happen? NTBI

More

Transfusion

NTBI

LCI

Free Radical, esp. OH•

Organelle damage

LPI

Tf Tf Tf Tf

Tf

Tf

Ferroportin

What happen?

from Labile iron to Fibrosis & Cell death

Pathophysiology of iron overload

Intestinal iron absorption is controlled by hepcidin, a peptide hormone that generally adapts duodenal iron absorption to the demands of erythropoiesis and regulates the release of iron from macrophages [7, 8]. Iron is stored in ferritin, an intracellular iron storage protein primarily found in the liver and in the macrophage system. During infection and other inflammatory states, hepcidin production is increased, leading to a decrease in both intestinal iron absorption and macrophage iron release. The resulting decrease in transfer- rin saturation helps to deprive circulating microorganisms of iron, but also restricts iron availability for erythropoiesis, thereby causing anemia of chronic inflammation.

Circulating iron is bound to transferring, and when the binding capacity of transferrin is exceeded, non-transferrin- bound iron (NTBI) species appear in the plasma [9]. The portion of NTBI with the weakest binding to plasma bio- molecules is labile plasma iron (LPI), which is redox-active and able to permeate organs such as the heart and liver, where it contributes to the generation of reactive oxygen species (ROS) [10]. While hydrogen peroxide and super- oxide are comparatively non-toxic and can actually function as physiological signaling molecules, their reaction with unliganded or incompletely liganded iron ions creates more damaging oxygen radicals, in particular, the extremely reactive hydroxyl radical (OH•) [11]. While LPI is detected almost exclusively in pathological conditions, LCI is a normal component that is regulated to serve the cellular iron requirements and to prevent an excess of redox- reactive iron that may trigger cellular damage. High LCI levels catalyze increased ROS generation through the Haber–Weiss and Fenton reactions, which may eventually overwhelm the cell antioxidant capacity and deplete cellular antioxidants like reduced glutathione (GSH), resulting in tissue oxidative damage and organ dysfunction (Fig. 1).

Decreased life expectancy in transfusion-dependent MDS: identifying the culprit

Transfusion dependency is strongly associated with decreased survival in MDS patients (Fig. 2), as shown by Malcovati et al. who demonstrated a dose-dependent impact of transfu- sion requirements on overall and leukemia-free survival [12].

These observations were recently corroborated in a large, retrospective, multicenter analysis from Spain [13]. How- ever, the association between transfusion dependency and decreased life expectancy in patients with MDS might have several causes. Patients may develop clinical complications resulting from iron overload due to inadequate iron chelation therapy; however, transfusion dependency could merely indicate a more severe bone marrow disease with complica- tions independent of iron overload.

As the severity of bone marrow disease is at least partly determined by karyotype anomalies, one would expect transfusion dependency to lose its prognostic value when the karyotype is taken into account. However, several studies have shown that this is not the case. Transfusion dependency is a risk factor that is independent of cytogenetic risk groups in MDS [12], suggesting that the prognostic influence of transfusion dependency is not solely based on the severity of the underlying bone marrow disease but also on an additional component, which is most likely to be the effects of iron overload. A recent multi- variate analysis [13] showed that the prognostic impact of IO was independent of the World Health Organization (WHO) classification-based scoring system (WPSS) which already incorporates transfusion dependency [14]. There- fore, even after transfusion requirement had been taken into account, IO with SF levels above 1,000 ng/ml remained an independent prognostic factor, both for overall and leukemia- free survival.

Increased LPI

Hydroxyl radical generation Lipid peroxidation

Organelle damage TGF- β1

Collagen synthesis

Fibrosis Cell death

Lysosomal fragility Enzyme leakage

LPI, labile plasma iron; TGF, transforming growth factor

Fig. 1 Pathophysiology of iron overload. Adapted from [75]

Fig. 2 Impact of transfusion dependency on survival in MDS [12]

2 Ann Hematol (2011) 90:1–10

Cohen AR, et al. 2001

OH•

Mortality?

철중독과 연관된 사망에 가장 관계깊은 장기는?

1.Brain

2.Bone marrow 3.Heart

4.Liver

5.Pancreas

Sequelae by Iron Overload

Organ Dysfunction

• Hepatic cirrhosis

• Cardiomyopathy

• Cardiac impairment

• Diabetes mellitus

• Impaired growth

• Infertility

• Hypothyroidism

• Hypogonadism

Other anemias

Diamond-Blackfan syndrome ¹⁵ (a congenital hypoplastic anemia, in which few or no red blood cells are produced) and Fanconi anemia (a form of congenital aplastic anemia) ¹⁶ are two other rare anemias that may require frequent transfusions. Patients with Diamond-Blackfan syndrome usually are treated with

steroids, but many require transfusions once they stop responding to that therapy. ¹⁵ Patients with Fanconi anemia also may require frequent transfusions to manage symptomatic anemia. ¹⁶ Patients with these ane- mias often develop iron overload because of their need for multiple transfusions.

Other causes

Patients sometimes may require frequent transfusions after bone mar- row or stem cell transplantations where their engraftments have been slow or delayed. In addition, patients who undergo stem cell transplantations may have been heavily transfused during their prior therapies and may be iron overloaded at the time of transplantation. Iron overload after stem cell transplantation has been associated with higher morbidity and mortality, especially in patients with invasive aspergillosis, a known complication of transplantation. ⁷

Cytopenias, including anemia, are relatively common side effects of several types of chemotherapy. Although erythropoietin-stimu- lating agents are used widely to raise hemoglobin and hematocrit levels in patients who undergo chemotherapy, many patients still may require frequent transfusions. Patients may need transfusions if

they do not respond to these agents or experience heavy bleeding from menses in women or a hemorrhagic event. ^8,9

V. WHAT ARE THE POTENTIAL EFFECTS OF

TRANSFUSIONAL IRON OVERLOAD ON YOUR PATIENTS?

Excess iron accumulates in the heart, liver, and other vital organs. ^1,3 Surpluss iron cannot be removed naturally by the body, and it puts the organs at risk of serious damage. ³ The result of this damage is fibrosis and organ dysfunction. ^3,17

In addition, once the body’s storage capacity for iron is exceeded, non-transferrin- bound iron is created. ^1,18 This is a toxic form of iron that causes oxidative stress, attacking organ systems at the cellular level causing tissue damage. ^1,6,19

The damage caused by transfusional iron overload may not be evident

immediately. ^7,19 In fact, patients can be asymptomatic as the iron invades and accumulates in their organs. ^7,19

Transfusional iron overload can lead to any of the following serious condtions. 1,20,21,22

❖ Impaired growth, infertility (pituitary gland) ❖ Hepatic cirrhosis (liver)

❖ Hypothyroidism (thyroid gland)

❖ Cardiomyopathy, cardiac impairment (heart) ❖ Diabetes mellitus (pancreas)

❖ Hypogonadism (gonadal glands)

Figure 3. Potential Organ Damage From Iron Overload

Years of Chelation Therapy

Proportion without Cardiac Disease

1.00

0.75

0.50

0.25

0.00

0 2 4 6 8 10 12 14 16

Figure 2. Uncontrolled Iron Overload Increases the Risk of Life-Threatening Morbidity in B-thalassemia

From Olivieri and Brittenham.

¹³

Exjade_bro_finalrev.indd 6-7 11/19/07 10:44:23 AM

Thyroid gland Heart

Pancreas

Gonadal gland Pituitary

gland

Thyroid gland

Liver

Sequelae by Iron Overload

Organ Dysfunction

• Hepatic cirrhosis

• Cardiomyopathy

• Cardiac impairment

• Diabetes mellitus

• Impaired growth

• Infertility

• Hypothyroidism

• Hypogonadism

Other anemias

Diamond-Blackfan syndrome ¹⁵ (a congenital hypoplastic anemia, in which few or no red blood cells are produced) and Fanconi anemia (a form of congenital aplastic anemia) ¹⁶ are two other rare anemias that may require frequent transfusions. Patients with Diamond-Blackfan syndrome usually are treated with

steroids, but many require transfusions once they stop responding to that therapy. ¹⁵ Patients with Fanconi anemia also may require frequent transfusions to manage symptomatic anemia. ¹⁶ Patients with these ane- mias often develop iron overload because of their need for multiple transfusions.

Other causes

Patients sometimes may require frequent transfusions after bone mar- row or stem cell transplantations where their engraftments have been slow or delayed. In addition, patients who undergo stem cell transplantations may have been heavily transfused during their prior therapies and may be iron overloaded at the time of transplantation. Iron overload after stem cell transplantation has been associated with higher morbidity and mortality, especially in patients with invasive aspergillosis, a known complication of transplantation. ⁷

Cytopenias, including anemia, are relatively common side effects of several types of chemotherapy. Although erythropoietin-stimu- lating agents are used widely to raise hemoglobin and hematocrit levels in patients who undergo chemotherapy, many patients still may require frequent transfusions. Patients may need transfusions if

they do not respond to these agents or experience heavy bleeding from menses in women or a hemorrhagic event. ^8,9

V. WHAT ARE THE POTENTIAL EFFECTS OF

TRANSFUSIONAL IRON OVERLOAD ON YOUR PATIENTS?

Excess iron accumulates in the heart, liver, and other vital organs. ^1,3 Surpluss iron cannot be removed naturally by the body, and it puts the organs at risk of serious damage. ³ The result of this damage is fibrosis and organ dysfunction. ^3,17

In addition, once the body’s storage capacity for iron is exceeded, non-transferrin- bound iron is created. ^1,18 This is a toxic form of iron that causes oxidative stress, attacking organ systems at the cellular level causing tissue damage. ^1,6,19

The damage caused by transfusional iron overload may not be evident

immediately. ^7,19 In fact, patients can be asymptomatic as the iron invades and accumulates in their organs. ^7,19

Transfusional iron overload can lead to any of the following serious condtions. 1,20,21,22

❖ Impaired growth, infertility (pituitary gland) ❖ Hepatic cirrhosis (liver)

❖ Hypothyroidism (thyroid gland)

❖ Cardiomyopathy, cardiac impairment (heart) ❖ Diabetes mellitus (pancreas)

❖ Hypogonadism (gonadal glands)

Figure 3. Potential Organ Damage From Iron Overload

Years of Chelation Therapy

Proportion without Cardiac Disease

1.00

0.75

0.50

0.25

0.00

0 2 4 6 8 10 12 14 16

Figure 2. Uncontrolled Iron Overload Increases the Risk of Life-Threatening Morbidity in B-thalassemia

From Olivieri and Brittenham.

¹³

Exjade_bro_finalrev.indd 6-7 11/19/07 10:44:23 AM

Thyroid gland Heart

Pancreas

Gonadal gland Pituitary

gland

Thyroid gland

Liver

function and altered loading conditions in the setting of anemia.

^63e65

High myocardial oxygen demand secondary to a dilated/hypertrophied left ventricle in the setting of anemia has been shown to cause inducible ischemia, de- spite a normal coronary angiogram

⁶⁶

and in patients with severe anemia, high-output heart failure can develop.

^63e66

In patients with sickle cell anemia, vaso-occlusion due to thrombosis and dysplasia of the coronary vessels leading to myocardial perfusion abnormalities, myocardial infarc- tion, and multifocal fibrosis in these patients.

^67e69

Elevated body iron stores are associated with increased risk of myocardial infarction in Finnish men

⁷⁰

and carriers of the hemochromatosis gene, in combination with tradi- tional vascular risk factors, have an increased risk of cardio- vascular events.

^70,71

In contrast, volunteer blood donors with a high donation frequency have decreased oxidative stress and enhanced vascular function compared with low fre- quency donors.

⁷²

Iron-mediated endothelial dysfunction and increased arterial stiffness in patients with primary hemochromatosis,

⁷³

b-thalassemia major,

⁷⁴

and sickle cell anemia

⁷⁵

can compromise coronary blood flow regulation and reduces the mechanical efficiency of the heart. In addi- tion, impairment of the myocardial blood flow reserve corre- lates with the myocardial dysfunction in patients with sickle cell anemia.

⁶⁸

Moderate iron loading may accelerate throm- bus formation after arterial injury, which may increase

vascular events.

^76,77

However, several recent studies have failed to demonstrate a definitive role of serum ferritin or pri- mary hemochromatosis genotype on vascular function or the risk of coronary artery disease, suggesting that the relation- ship is more complicated than originally envisioned.

^78,79

Pulmonary Hypertension and Right Ventricular Dysfunction

Pulmonary hypertension secondary to pulmonary vaso- occlusion has long been recognized in patients with sickle cell anemia.

^80e82

Sickle cell disease and thalassemic syn- dromes are characterized by a state of nitric oxide resistance from chronic hemolysis, which reduces nitric oxide bioavail- ability leading to endothelial dysfunction.

⁸³

Hemolysis re- leases erythrocyte arginase, which limits L-arginine bioavailability, and erythrocyte hemoglobin, which scav- enges nitric oxide resulting in endothelial dysfunction, vaso- constriction, and increased thrombosis, leading to pulmonary hypertension and increased mortality.

^83,84

Chronic thrombo- embolic disease may also contribute to the pulmonary hyper- tension in these patients.

⁷⁷

Pulmonary hypertension (tricuspid regurgitation velocity $2.5 m/s) and diastolic dys- function (mitral E/A ratio !1) are independent predictors of increased mortality in patients with sickle cell disease.

^36,85

Elevated plasma levels of N-terminal pro-brain natriuretic

Fig. 2. Interaction between Iron-mediated Oxidative Stress and Excitation-Contraction Coupling in a Cardiomyocyte. ROS, Reactive Oxygen Species; SERCA2a, Sarcoplasmic Reticulum Ca^2þATPase isoform 2; NCX, Sodium-Calcium Exchanger; RyR2, Ryanodine Receptor 2; SR, Sarcoplasmic Reticulum; PLN, Phospholamban; SLN, Sarcolipin.

Iron-Overload Cardiomyopathy

"

Murphy and Oudit

891

Murphy CJ, et al. J Card Fail. 2010

Cardiac damage

• Disastolic dysfunction

• Systolic dysfuction

• ^Arrhythmia

• Dilated cardiomyopathy

C O M M E N T A R Y

Voltage-gated Ca

²⁺

channels as key mediators of iron- transport and iron-overload cardiomyopathy: L-type vs.

T-type Ca

⁺

channels

Iron-overload cardiomyopathy, characterized by diastolic and systolic dysfunction and arrhythmias, results from genetic and acquired iron-overload conditions (1–3). The prevalence and clinical burden of secondary iron overload are increasing worldwide and are primarily because of blood transfusion in patients with hemoglobinopathies, namely thalassemia and sickle cell anemia. Voltage-gated Ca²⁺ chan- nels, which include the L-type (LTCC) and T-type Ca²⁺

channels (TTCC), are abundantly expressed in the heart and are key regulators of the excitation–contraction coupling and pacing activity in the heart (Fig. 1). In iron-overloaded conditions, non-transferrin-bound iron (NTBI) enters the cardiomyocytes through L-type Ca²⁺ channels and divalent- metal transporter (DMT1) and leads to iron-overload cardio- myopathy (3, 4). The use of calcium channel blockers

(CCBs) may represent a novel therapeutic tool to prevent and treat iron-overload cardiomyopathy (3).

In this issue, Kumfu et al. (5) showed that in an iron-over- loaded thalassemic murine model, the use of efonidine, a pro- posed specific blocker of TTCC, lowered mortality, prevented myocardial iron deposition and oxidative stress, and resulted in improved cardiac function. Iron-induced oxidative stress, a well-known mediator of iron-mediated tissue injury (6), and heart rate variability, a measure of the cardiac autonomic con- trol, were restored by efonidipine. Specific LTCC blockers (verapamil and nifedipine) along with the DMT blocker (ebselen) were also all effective against iron-overload cardio- myopathy in this experimental setting, while deferoxamine, a well-known iron chelator, was used as a positive control. In the normal healthy heart, TTCC are specifically confined to

SR T-Tubule

3 Na⁺

K⁺

T-Tubule

Sarcolemma

Ca²⁺

Fe²⁺

Ryanodine Receptors T-type Calcium Channel

NCX k⁺ Channel

SERCA 2a Phospholamban

ROS Myofilaments

Ca²⁺

Ca²⁺

Mitochondrion

Fe²⁺ Fe²⁺

2+

Na⁺ Channel

Na⁺ Fe²⁺ Fe²⁺

L-type Calcium Channel

Figure 1 Role of voltage-gated Ca²⁺ channels in iron transport and iron-mediated oxidative stress and the excitation–contraction coupling in a cardiomyocyte. ROS, reactive oxygen species; SERCA2a, sarcoplasmic reticulum Ca²⁺ATPase isoform 2; NCX, sodium–calcium exchanger; SR, sarcoplasmic reticulum.

©2012 John Wiley & Sons A/S 1

doi:10.1111/j.1600-0609.2012.01782.x European Journal of Haematology

Cardiac damage

Das SK, et al. Eur J Haematol. 2010

remains controversial as other groups show that neither MDA nor 4-HNE directly impacts HSC activa- tion.^138,139 Rather, it is likely that oxidation-derived events perpetuate already activated HSCs.^140,141 The precise mechanisms and pathways linking excess hepa- tocyte and Kupffer cell iron-loading, oxidant stress, and HSC activation in hemochromatosis are not fully under- stood and warrant further study.

Role of Ferritin and Transferrin in HSC Activation

The traditionally ascribed function of ferritin is the intracellular storage of iron in a nontoxic but biolog-

ically available form. Either during iron overload or in conditions of chronic inflammation, serum ferritin becomes markedly elevated and is proposed to reflect either body iron stores (as seen in hemochromatosis) or the body’s inflammatory status, respectively. The pre- cise reason or mechanisms for this elevation in serum ferritin levels are unknown, but proinflammatory cyto- kines have been shown to play a role.¹⁴² L-subunit ferritin is more tightly regulated by iron at a posttran- scriptional level than H-ferritin;¹⁴³ indeed, regulation of H- and L-ferritin genes occurs under conditions of such significant iron overload that oxidative damage or inflammation may be the more relevant signals.^144,145It has recently been postulated that ferritin may have

Figure 2 Potential mechanisms associated with iron overload-induced HSC activation. The deposition of iron in hepatocytes leads to cellular injury and apoptosis and/or necrosis. Phagocytosis of damaged hepatocytes by Kupffer cells is proposed to lead to the production of a variety of molecules capable of impacting on the transformation of HSC into myofibroblasts. MDA, 4-HNE, TGF-b₁, IL-6, tissue ferritin, and transferrin may play a role in aspects of this activation process, derived from either hepatocytes or Kupffer cells. Tissue-derived ferritin acts as a cytokine inducing NFkB-dependent proinflammatory molecules including RANTES, iNOS, ICAM-1, IL-1b,⁶² and IL-6 (Ruddell and Ramm, unpublished) in HSCs. These molecules may be involved in inflammation and chemotaxis associated with wound healing, fibrogenesis, and hepatic regeneration. The role of serum ferritin and other molecules derived from extrahepatic sources via the circulatory system, such as transferrin, CCL2, CCL5, IGF, IL-6, IL-1b, TGF-b, PDGF, TNF-a, IL-10, in iron-induced hepatic fibrosis remain to be adequately investigated. L, lymphocyte; P, platelet; LPC, liver progenitor cell; HSC, hepatic stellate cell; CCL; chemokine (C-C) motif ligand; MDA, malondialdehyde; 4-HNE, 4-hydroxynonenal;

TGF, transforming growth factor; IL, interleukin; TNF, tumor necrosis factor; PDGF, platelet-derived growth factor; IGF, insulin-like growth factor; RANTES, regulated upon activation, normal T-cell expressed and secreted; ICAM-1, intracellular adhesion molecule-1; iNOS, inducible nitric oxide synthase. Dashed arrows represent potential pathways requiring further investigation.

280 SEMINARS IN LIVER DISEASE/VOLUME 30, NUMBER 3 2010

Downloaded by: Yonsei Medical Library. Copyrighted material.

Hepatic damage

Ramm GA, et al. Semin Liver Dis. 2010

remains controversial as other groups show that neither MDA nor 4-HNE directly impacts HSC activa- tion.^138,139 Rather, it is likely that oxidation-derived events perpetuate already activated HSCs.^140,141 The precise mechanisms and pathways linking excess hepa- tocyte and Kupffer cell iron-loading, oxidant stress, and HSC activation in hemochromatosis are not fully under- stood and warrant further study.

Role of Ferritin and Transferrin in HSC Activation

The traditionally ascribed function of ferritin is the intracellular storage of iron in a nontoxic but biolog-

ically available form. Either during iron overload or in conditions of chronic inflammation, serum ferritin becomes markedly elevated and is proposed to reflect either body iron stores (as seen in hemochromatosis) or the body’s inflammatory status, respectively. The pre- cise reason or mechanisms for this elevation in serum ferritin levels are unknown, but proinflammatory cyto- kines have been shown to play a role.¹⁴² L-subunit ferritin is more tightly regulated by iron at a posttran- scriptional level than H-ferritin;¹⁴³ indeed, regulation of H- and L-ferritin genes occurs under conditions of such significant iron overload that oxidative damage or inflammation may be the more relevant signals.^144,145It has recently been postulated that ferritin may have

Figure 2 Potential mechanisms associated with iron overload-induced HSC activation. The deposition of iron in hepatocytes leads to cellular injury and apoptosis and/or necrosis. Phagocytosis of damaged hepatocytes by Kupffer cells is proposed to lead to the production of a variety of molecules capable of impacting on the transformation of HSC into myofibroblasts. MDA, 4-HNE, TGF-b₁, IL-6, tissue ferritin, and transferrin may play a role in aspects of this activation process, derived from either hepatocytes or Kupffer cells. Tissue-derived ferritin acts as a cytokine inducing NFkB-dependent proinflammatory molecules including RANTES, iNOS, ICAM-1, IL-1b,⁶² and IL-6 (Ruddell and Ramm, unpublished) in HSCs. These molecules may be involved in inflammation and chemotaxis associated with wound healing, fibrogenesis, and hepatic regeneration. The role of serum ferritin and other molecules derived from extrahepatic sources via the circulatory system, such as transferrin, CCL2, CCL5, IGF, IL-6, IL-1b, TGF-b, PDGF, TNF-a, IL-10, in iron-induced hepatic fibrosis remain to be adequately investigated. L, lymphocyte; P, platelet; LPC, liver progenitor cell; HSC, hepatic stellate cell; CCL; chemokine (C-C) motif ligand; MDA, malondialdehyde; 4-HNE, 4-hydroxynonenal;

TGF, transforming growth factor; IL, interleukin; TNF, tumor necrosis factor; PDGF, platelet-derived growth factor; IGF, insulin-like growth factor; RANTES, regulated upon activation, normal T-cell expressed and secreted; ICAM-1, intracellular adhesion molecule-1; iNOS, inducible nitric oxide synthase. Dashed arrows represent potential pathways requiring further investigation.

280 SEMINARS IN LIVER DISEASE/VOLUME 30, NUMBER 3 2010

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Hepatic damage

Ramm GA, et al. Semin Liver Dis. 2010

Iron Overload & Hematopoiesis

• Negative effect of oxidative stress on

hematopoietic stem & progenitor cells by iron overload

• Increased oxidative stress in RBC, PLT, & PML from MDS pts with iron overload

• ROS buildup in HSCs compromises their function

as a result of potential damage to their DNA leading to loss of quiescence and alteration of HSC cycling.

Ghoti H, et al. Eur J Haematol. 2007

Ghaffari S. Antioxid Redox Signal. 2008

RA/RARS/5q–

(HR = 1.42, p < 0.001)

RCMD/RCMD-RS (HR = 1.33, p = 0.07)

180

C u m u la ti ve p ro p o rti o n s u rv iv in g

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0 20 40 60 80 100 120 140 160

C u m u la ti ve p ro p o rti o n s u rv iv in g

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0 20 40 60 80 100 120 140 160 180

months months

s-ferritin (µg/L) 1,000

1,500 2,000 2,500

s-ferritin (µg/L) 1,000

1,500 2,000 2,500

Transfusion, Risk for Survival ?

Malcovati L, et al. Haematologica. 2006

Goldberg SL, et al. J Clin Oncol. 2010;28:2847

Goldberg SL, et al. J Clin Oncol. 2010;28:2847

Goldberg SL, et al. J Clin Oncol. 2010;28:2847

1.Iron metabolism

2.Transfusional iron overload 3.Measurement of body iron

4.Treatment for iron overload 5.National data

Contents

NTBI

LPI LCI

Tf Tf Tf Tf

Tf

Tf

Ferroportin

Ferritin

Tf TFR

DMT

s-Ferritin

Measurement of Body Iron

LPI

NTBI

LPI LCI

Tf Tf Tf Tf

Tf

Tf

Ferroportin

Ferritin

Tf TFR

DMT

s-Ferritin

Measurement of EC Iron

LPI

!

"

#

NTBI

LPI LCI

Tf Tf Tf Tf

Tf

Tf

Ferroportin

Ferritin

Tf TFR

DMT

s-Ferritin

Measurement of IC Iron

LPI

Tissue Iron

Measurement of Body Iron

1.Extracellular iron

-s-ferritin

-Transferrin

• indirectly measured as transferrin saturation, calculated using the s-iron & TIBC  

-LPI, NTBI

• by Nitrilotriacetic Acid & High-Performance Liquid Chromatography, Fluorescence Technique

• to evaluate body iron levels very accurately, although its use outside the clinical research setting is limited.

2.Intracellular iron

-Liver as LIC

-Heart as Cardiac iron

Measurement of Body Iron

1.Extracellular iron

-s-ferritin

-Transferrin

• indirectly measured as transferrin saturation, calculated using the s-iron & TIBC  

-LPI, NTBI

• by Nitrilotriacetic Acid & High-Performance Liquid Chromatography, Fluorescence Technique

• to evaluate body iron levels very accurately, although its use outside the clinical research setting is limited.

2.Intracellular iron

-Liver as LIC

-Heart as Cardiac iron Imaging or Biopsy

Measurement of Body Iron

1.Extracellular iron

-s-ferritin

-Transferrin

• indirectly measured as transferrin saturation, calculated using the s-iron & TIBC  

-LPI, NTBI

• by Nitrilotriacetic Acid & High-Performance Liquid Chromatography, Fluorescence Technique

• to evaluate body iron levels very accurately, although its use outside the clinical research setting is limited.

2.Intracellular iron

-Liver as LIC

-Heart as Cardiac iron MRI or Biopsy

biopsy findings of iron deposition.

¹²²

The widespread use of cardiac MRI and T2* measurement has lead to an increased detection of myocardial iron overload and has had a positive impact on reducing the mortality associated with secondary iron overload.

119,121,123

Tagged MRI can measure cardiac stress and strain rate and torsion, which may provide further insight into the early changes in iron-overload cardiomyopa- thy.

^124,125

Endomyocardial Biopsy

Endomyocardial biopsy are not routinely used but can serve as definitive assessment of tissue iron stores while al- lowing a detailed histological assessment of end-organ dam- age.

¹²⁶

Given the inherent risk of endomyocardial biopsy and it limited clinical utility in detecting iron-overload cardiomy- opathy, cardiac MRI is becoming a favored noninvasive tool to estimate myocardial iron concentration. Myocardial iron deposition is heterogeneous with the epicardium having the

highest deposits of iron thereby limiting the utility of endo- myocardial biopsy.

^45,126,127

Although liver iron levels is a measure of overall total body iron and can be measured via needle biopsy, hepatic iron deposition does not correlate with myocardial iron deposition.

⁴⁵

Treatment of Iron-overload Cardiomyopathy

Iron Removal and Heart Failure Management

The mainstay therapy for excessive iron deposition in pa- tients with primary and secondary hemochromatosis is phlebotomy and iron chelation, respectively, which are de- signed to promote whole-body iron removal. In patients with primary hemochromatosis, maintenance phlebotomy schedule should be continued after primary iron depletion to prevent reaccumulation of iron with a reasonable goal is to keep the serum ferritin concentration at 50 ng/mL or less.

^28,30,31

Phlebotomy therapy initiated early can be

Fig. 3. The value of cardiac MRI and the evaluation of T2* in relation to heart failure and arrhythmias in 652 patients with thalassemia major and secondary iron-overload. Modified from Kirk P et al. Circulation 2009. Receiver-operating characteristic curve for the prediction of heart failure within 1 year of MR scanning (A) and KaplaneMeier curves showing the occurrence of heart failure over 1 year according to baseline cardiac T2* values of O10, 8 to 10, 6 to ! 8, and ! 6 ms (B). Receiver-operating characteristic curve for prediction of arrhythmia within 1 year of MR scanning (C) and KaplaneMeier curves showing the occurrence of arrhythmia over 1 year according to cardiac T2* values of O20, 10 to 20, and !10 ms (D). The diagonal line shows the performance of a non-diagnostic test (A, C).

Reproduced with permission from Wolters Kluwer Health.

Iron-Overload Cardiomyopathy ! Murphy and Oudit 895

biopsy findings of iron deposition.

¹²²

The widespread use of cardiac MRI and T2* measurement has lead to an increased detection of myocardial iron overload and has had a positive impact on reducing the mortality associated with secondary iron overload.

119,121,123

Tagged MRI can measure cardiac stress and strain rate and torsion, which may provide further insight into the early changes in iron-overload cardiomyopa- thy.

^124,125

Endomyocardial Biopsy

Endomyocardial biopsy are not routinely used but can serve as definitive assessment of tissue iron stores while al- lowing a detailed histological assessment of end-organ dam- age.

¹²⁶

Given the inherent risk of endomyocardial biopsy and it limited clinical utility in detecting iron-overload cardiomy- opathy, cardiac MRI is becoming a favored noninvasive tool to estimate myocardial iron concentration. Myocardial iron deposition is heterogeneous with the epicardium having the

highest deposits of iron thereby limiting the utility of endo- myocardial biopsy.

^45,126,127

Although liver iron levels is a measure of overall total body iron and can be measured via needle biopsy, hepatic iron deposition does not correlate with myocardial iron deposition.

⁴⁵

Treatment of Iron-overload Cardiomyopathy

Iron Removal and Heart Failure Management

The mainstay therapy for excessive iron deposition in pa- tients with primary and secondary hemochromatosis is phlebotomy and iron chelation, respectively, which are de- signed to promote whole-body iron removal. In patients with primary hemochromatosis, maintenance phlebotomy schedule should be continued after primary iron depletion to prevent reaccumulation of iron with a reasonable goal is to keep the serum ferritin concentration at 50 ng/mL or less.

^28,30,31

Phlebotomy therapy initiated early can be

Fig. 3. The value of cardiac MRI and the evaluation of T2* in relation to heart failure and arrhythmias in 652 patients with thalassemia major and secondary iron-overload. Modified from Kirk P et al. Circulation 2009. Receiver-operating characteristic curve for the prediction of heart failure within 1 year of MR scanning (A) and KaplaneMeier curves showing the occurrence of heart failure over 1 year according to baseline cardiac T2* values of O10, 8 to 10, 6 to ! 8, and ! 6 ms (B). Receiver-operating characteristic curve for prediction of arrhythmia within 1 year of MR scanning (C) and KaplaneMeier curves showing the occurrence of arrhythmia over 1 year according to cardiac T2* values of O20, 10 to 20, and !10 ms (D). The diagonal line shows the performance of a non-diagnostic test (A, C).

Reproduced with permission from Wolters Kluwer Health.

Iron-Overload Cardiomyopathy ! Murphy and Oudit 895

Role of Cardiac MR imaging

Kirk P, et al. Circulation. 2009

Better than Liver MR imaging or Ferritin for both HF & arrhythimia

To measure Liver Iron Content

Liver biopsy

• Gold standard, accurate measure

• Invasive, difficult to repeat

SQUID ; super-conducting quantum interference device

• Accurate, noninvasive

• Few available worldwide

Liver MRI

• Accurate, noninvasive

• Special software required

SQUID ; super-conducting quantum interference device

SQUID biosusceptometry

Liver MRI, R2*

The semiautomatic postprocessing method is described in Fig. 1. (i) Define liver ROI (Fig. 1A). In each slice, a large ROI was drawn to outline the entire liver slice. Care was taken to avoid the interfaces with stomach, kidney and liver periphery. (ii) Initial T2⁎ estimation. In each pixel within the liver ROI, T2⁎ was calculated by fitting the monoexponen- tial signal decay model using all data points; noisy pixels

(bad pixels) were temporarily excluded. (iii) Vessel extrac- tion. A T2⁎ histogram was generated for all fitted pixels;

hepatic vessels and peripheral tissues were identified by adjusting the threshold value to include the area under the major peak corresponding to liver parenchyma and exclude higher T2⁎ values corresponding to vessels (Fig. 1B). An image overlay of red pixels representing liver tissue was used

T2* Histogram

7000 6000 5000 4000 3000 2000 1000

00 5 10

T2* (ms)

Echo #

TE (ms) Averaged signal intensity (S)Pixel Count Signal intensity (S)

15

140 120 100 80 60 40 20 00

180 160

2 4 6 8 10 12

Noise level

120

80

40

00 5 10 15 20

A B

C D

E F

Fig. 1. Semiautomatic postprocessing method for whole liver R2⁎ measurement. (A) Whole liver ROI including vessel areas. (B) T2⁎ histogram of all pixels within the ROI. A threshold (dashed line) was set to extract the pixels belonging to vessels. (C) Segmented liver tissues (red) excluding vessel areas and bad pixels (green). (D) Gross noise level estimated from the averaged signal intensity of the segmented liver tissues. (E) Resultant R2⁎ map overlaid with nonfitted pixels. (F) Averaged signal decay of all pixels over the entire liver ROI (vessels and nonfitted pixels excluded). Data points under twice of the noise baseline (gray area) are excluded before fitting. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) 3 J. Deng et al. / Magnetic Resonance Imaging xx (2012) xxx–xxx

The semiautomatic postprocessing method is described in Fig. 1 . (i) Define liver ROI (Fig. 1A). In each slice, a large ROI was drawn to outline the entire liver slice. Care was taken to avoid the interfaces with stomach, kidney and liver periphery. (ii) Initial T2⁎ estimation. In each pixel within the liver ROI, T2⁎ was calculated by fitting the monoexponen- tial signal decay model using all data points; noisy pixels

(bad pixels) were temporarily excluded. (iii) Vessel extrac- tion. A T2⁎ histogram was generated for all fitted pixels;

hepatic vessels and peripheral tissues were identified by adjusting the threshold value to include the area under the major peak corresponding to liver parenchyma and exclude higher T2⁎ values corresponding to vessels (Fig. 1B). An image overlay of red pixels representing liver tissue was used

T2* Histogram

7000 6000 5000 4000 3000 2000 1000

00 5 10

T2* (ms)

Echo #

TE (ms) A ver aged signal intensity (S) Pix el Count Signal intensity (S)

15

140 120 100 80 60 40 20 00

180 160

2 4 6 8 10 12

Noise level

120

80

40

00 5 10 15 20

A B

C D

E F

Fig. 1. Semiautomatic postprocessing method for whole liver R2⁎ measurement. (A) Whole liver ROI including vessel areas. (B) T2⁎ histogram of all pixels within the ROI. A threshold (dashed line) was set to extract the pixels belonging to vessels. (C) Segmented liver tissues (red) excluding vessel areas and bad pixels (green). (D) Gross noise level estimated from the averaged signal intensity of the segmented liver tissues. (E) Resultant R2⁎ map overlaid with nonfitted pixels. (F) Averaged signal decay of all pixels over the entire liver ROI (vessels and nonfitted pixels excluded). Data points under twice of the noise baseline (gray area) are excluded before fitting. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) 3 J. Deng et al. / Magnetic Resonance Imaging xx (2012) xxx–xxx

The semiautomatic postprocessing method is described in Fig. 1. (i) Define liver ROI (Fig. 1A). In each slice, a large ROI was drawn to outline the entire liver slice. Care was taken to avoid the interfaces with stomach, kidney and liver periphery. (ii) Initial T2⁎ estimation. In each pixel within the liver ROI, T2⁎ was calculated by fitting the monoexponen- tial signal decay model using all data points; noisy pixels

(bad pixels) were temporarily excluded. (iii) Vessel extrac- tion. A T2⁎ histogram was generated for all fitted pixels;

hepatic vessels and peripheral tissues were identified by adjusting the threshold value to include the area under the major peak corresponding to liver parenchyma and exclude higher T2⁎ values corresponding to vessels (Fig. 1B). An image overlay of red pixels representing liver tissue was used

T2* Histogram

7000 6000 5000 4000 3000 2000 1000

00 5 10

T2* (ms)

Echo #

TE (ms) A ver aged signal intensity (S) Pix el Count Signal intensity (S)

15

140 120 100 80 60 40 20 00

180 160

2 4 6 8 10 12

Noise level

120

80

40

00 5 10 15 20

A B

C D

E F

Fig. 1. Semiautomatic postprocessing method for whole liver R2⁎ measurement. (A) Whole liver ROI including vessel areas. (B) T2⁎ histogram of all pixels within the ROI. A threshold (dashed line) was set to extract the pixels belonging to vessels. (C) Segmented liver tissues (red) excluding vessel areas and bad pixels (green). (D) Gross noise level estimated from the averaged signal intensity of the segmented liver tissues. (E) Resultant R2⁎ map overlaid with nonfitted pixels. (F) Averaged signal decay of all pixels over the entire liver ROI (vessels and nonfitted pixels excluded). Data points under twice of the noise baseline (gray area) are excluded before fitting. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) 3 J. Deng et al. / Magnetic Resonance Imaging xx (2012) xxx–xxx

T2* R2*

Deng J, et al. Magn Reson Imaging. 2012

1.Iron metabolism

2.Transfusional iron overload 3.Measurement of body iron

4.Treatment for iron overload 5.National data

Contents

Aydinok Y, et al. Eur J Haematol. 2015;95:244

Aydinok Y, et al. Eur J Haematol. 2015;95:244

Where?

혈중 유리철 감소에 도움이 되지 않는 물질은?

1.Transferrin

2.DMT inhibitor 3.Hepcidin

4.Iron chelator

5.Feroportin agonist

Chelation

M

M

M

M

M

M

monodentate bidentate tridentate tetradentate ……

……

Iron Chelator

DEFEROXAMINE

• as deferoxamin mesylate, hexadentate (1:1 binding to Fe)

• t 1/2 : 20~30 min, slow SC/IV infusion for 8~12 hours ,

• 25~60 mg/kg/day, 5~7/week

• urinary & faecal excretion

Problems

• local reactions, ophthalmologic, auditary, growth retardation,...

• poor compliance

Oral Iron Chelator

DEFERIPRONE

• didentate (3:1 binding to Fe)

• t 1/2 : 3~4 h

• 75~100 mg/kg/day

• urinary excretion

Problems

• agranulocytosis

• three times daily

Oral Iron Chelator

DEFERASIROX

• tridentate (2:1 binding to Fe)

• t 1/2 : 8~16 h, once daily

• 20~30 mg/kg/day

• faecal excretion

Problems

• renal insufficiency

• GI disturbance