Iron Overload in NTDT
3rd Pan-European Conference on
Haemoglobinopathies & Rare Anaemias
Limassol, 24 – 26 October 2012
Khaled M. Musallam, MD, PhD
American University of Beirut, Beirut, Lebanon
University of Milan, Milan, Italy
Excess Iron in NTDT
● Primary: Increased intestinal absorption
● Secondary: Blood transfusions
Musallam KM et al. Blood Rev 2012;26:16-9.
Transfusions in NTDT
● Occasional
•
•
•
Infection
Pregnancy
Surgery
● More regular
•
•
Poor growth and development
Specific complications (advanced age)
 Leg ulcer, pulmonary hypertension, extramedullary
hematopoietic psuedotumors, thrombotic disease
Musallam KM et al. Cold Spring Harb Perspect Med 2012;2:a013482.
Primary Iron Overload
Ineffective erythropoiesis, Anemia, Hypoxia
GDF-15
TWGF-1
HIFs
Tmprss6
? Other erythroid regulators
↑ Erythropoietin
↓ Hepcidin
↓ Ferroportin
↑ Intestinal absorption
↑ Release of recycled iron
from reticuloendothelial system
↑ Liver iron concentration
↓ Than expected serum ferritin level
Musallam KM et al. Blood Rev 2012;26:16-9.
Ginzburg Y and Rivella S. Blood 2011;118:4321-30.
Primary Iron Overload (2)
r=0.63, P=0.0141
1. Musallam KM et al. Blood Cells Mol Dis 2011;47:232-4.
2. Taher AT et al. Br J Haematol 2009;146:569-72.
r=0.36, P=0.0022
Iron Overload in NTDT
β-thalassemia intermedia2
●
Cumulative process
•
●
Slower than transfusional
siderosis
•
•
1.
2.
3.
4.
5.
6.
7.
Positive correlations between
iron overload indices and
advancing age1-5
3-4 mg/day or as much as
1,000 mg/year6
Annual increase in liver iron
concentration of 0.38 ± 0.49
mg Fe/g dry7
Taher A et al. Br J Haematol 2009;146:569-72.
Taher AT et al. Br J Haematol 2010;150:486-9.
Taher A et al. Haematologica 2008;93:1584-6.
Lal A et al. N Engl J Med 2011;364:710-8.
Chen FE et al. N Eng J Med 2000;343:544-50.
Musallam KM et al. Blood Rev 2012;26:16-9.
Taher AT et al. Blood 2012;120:970-7.
Serum ferritin (µg/L)
3000
2500
2000
1500
1000
r=0.65
P<0.001
500
0
0
20
40
Age (years)
Hemoglobin H disease5
60
Considerable iron overload
warranting concern?
● Iron overload as early as 5 years1
● Iron-related morbidities beyond 10 years2
● Mean LIC values at cross-sectional
assessment of NTDT cohorts with a mean age
in early-mid adulthood range between 7 and 15
mg Fe/g dw3-7
1.
2.
3.
4.
5.
6.
7.
Cossu P et al. Eur J Pediatr 1981;137:267-71.
Taher AT et al. Br J Haematol 2010;150:486-9.
Origa R et al. Haematologica 2007;92:583-8.
Musallam KM et al. Haematologica 2011;96:1605-12.
Taher AT et al. Blood 2012;120:970-7.
Lal A et al. N Engl J Med 2011;364:710-8.
Pakbaz Z et al. Pediatr Blood Cancer 2007;49:329-32.
The Heart
30
Normal cardiac
R2*
65
LIC (mg Fe/g dry wt)
55
Cardiac T2* (ms)
Mild LIC (3–7 mg Fe/g dry wt)
25
60
50
45
40
35
30
Normal LIC (< 3 mg Fe/g dry wt)
Moderate LIC (7–15 mg Fe/g dry wt)
Severe LIC (> 15 mg Fe/g dry wt)
20
15
10
5
25
20
0
0
n=20
500
1000
1500
2000
2500
3000
3500
Serum ferritin (ng/mL)
0
20
n=49
40
60
80
Cardiac R2* (Hz)
No evidence of cardiac siderosis even in NTDT patients with
considerable iron overload1-4
1.
2.
3.
4.
Origa R et al. Haematologica 2008;93:1095-6.
Roghi A et al. Ann Hematol 2010;89:585-9.
Taher AT et al. Am J Hematol 2010;85:288-90.
Mavrogeni S et al. Int J Cardiovasc Imaging 2008;24:849-54.
100
The Liver
● Several case reports and case series suggest an
association between iron overload and hepatocellular
carcinoma in hepatitis C negative patients with NTDT1-4
1.
2.
3.
4.
Macaron J et al. Ann Hepatol 2012. In Press.
Restivo Pantalone G et al. Br J Haematol 2010;150:245-7.
Borgna-Pignatti C et al. Br J Haematol 2004;124:114-7.
Mancuso A. World J Hepatol 2010;2:171-4.
The Liver (2)
R2: 0.836
P<0.001
●
β-TI (n=42)
●
Median age 38 yrs, 50% men
●
Hepatitis C negative
●
28 non-chelated, 14 chelated
●
Two consecutive Transient
Elastography (FibroScan®)
measurements (median 2
yrs, range 1-3 yrs)
Non-chelated
Musallam KM et al. Blood Cells Mol Dis 2012;49:136-9.
Chelated
The Liver (3)
First
measurement
Last
measurement
Chelated
●
●
●
S <3 (n=11)
S <3 (n=11)
4.4 to 5.7 kPa, P<0.001
S 3 (n=1)
S 3 (n=3)
∆ TE in chelated patients:
S 4 (n=1)
7.0 to 4.7 kPa, P=0.005
S 5 (n=1)
∆ TE in non-chelated patients:
∆ TE/yr non-chelated vs. chelated:
+0.3 vs. -0.9 kPa/year, P<0.001
Non-chelated
S <3 (n=28)
S <3 (n=26)
S 3 (n=2)
Transient elastography values corresponding to fibrosis stages are: ≤7.9
kPa for S <3; >7.9 to 10.3 for S 3; >10.3 to 12.0 for S 4; and >12.0 for S 5.
Musallam KM et al. Blood Cells Mol Dis 2012;49:136-9.
Other Morbidities
168 non-chelated β-TI, mean age 35.2 yrs, mean LIC 8.4 mg Fe/g dw
LIC (mg Fe/g dry wt)
21
p = 0.490 p = 0.027 p = 0.002 p < 0.001
p = 0.245 p < 0.001 p = 0.682 p = 0.040 p < 0.001 p < 0.001
18
Morbidity
absent
15
Morbidity
present
12
9
6
3
On multivariate analysis, a 1 mg Fe/g dw increase in LIC was significantly
associated with higher odds of thrombosis, pulmonary hypertension,
hypothyroidism, osteoporosis, and hypogonadism
Adjusted for age, gender, splenectomy status, transfusion history, total
hemoglobin level, fetal hemoglobin level, platelet count, NRBC count, and
serum ferritin level
0
Musallam KM et al. Haematologica 2011;96:1605-12.
Other Morbidities (2)
Morbidity
LIC cut-off
(mg Fe/g
dry wt)
AUC
95% CI
Thrombosis
≥7
0.669 ± 0.049
0.573–0.765
0.001
70.5%
61.3%
2.86 (1.22–5.91)
Pulmonary
hypertension
≥6
0.684 ± 0.042
0.601–0.767
< 0.001
75%
58%
3.30 (1.54–7.08)
Vascularb
≥7
0.723 ± 0.039
0.647–0.800
< 0.001
66.3%
71.8%
3.76 (1.81–7.81)
Hypothyroidism
≥6
0.630 ± 0.056
0.521–0.739
0.025
76.7%
52.2%
2.65 (1.03–6.77)
Osteoporosis
≥9
0.796 ± 0.041
0.624–0.787
< 0.001
58.4%
81.3%
5.13 (2.46–10.71)
Hypogonadism
≥6
0.689 ± 0.053
0.585–0.793
0.002
78.6%
52.1%
3.35 (1.2–9.26)
Endocrinec
≥6
0.724 ± 0.039
0.647–0.801
< 0.001
71.3%
70.3%
4.05 (1.96–8.35)
aAdjusted
p value Sensitivity Specificity AOR (95% CI)a
for age, gender, splenectomy status, transfusion history, total hemoglobin level, fetal hemoglobin level, platelet count, NRBC count, and
serum ferritin level. Model was built using forward-stepwise selection. p ≤ 0.1 was used as the criterion for inclusion. Multi-colinearity was absent in the
model as evident from a variation inflation factor ≤ 3 (acceptable limit up to 10).
bPatients having PHT or thrombosis.
cPatients having hypothyroidism, osteoporosis, or hypogonadism.
Musallam KM et al. Haematologica 2011;96:1605-12.
Other Morbidities (3)
●
Probability of
Stenosis on MRA
1.0
29 β-TI
●
Splenectomized
●
Mean age 32 yrs
●
Significant
association between
the occurrence of
large-vessel
cerebrovascular
disease (MRA) and
high NTBI levels
Probability
>0.8
<0.7
<0.5
<0.3
<0.1
0.8
0.6
0.4
0.2
NTBI (µmol/l)
Total Hemoglobin (g/l)
Musallam KM et al. Eur J Haematol 2011;87:539-46.
Other Morbidities (4)
1.0
0.3
0.2
0.1
I
Probability of
abnormality on PET-CT
0.4
I
Significant association
between decreased
neuronal function (PET-CT)
and high LIC
0.5
I
●
0.6
I
Mean age 32 yrs
I
●
0.7
I
Splenectomized
I
●
0.8
I
30 β-TI
I
●
0.9
0
0
I
I
5
10
I
I
15
I
20
I
25
LIC (mg Fe/g dry wt)
Musallam KM et al. Ann Hematol 2012;91:235-41.
30
35
Association with vascular
disease truly causal?
Splenectomy
n (%)
Transfusion
n (%)
No
26 (55.3)
No
47 (28)
Vascular morbidity
n (%)
<7
23 (88.5)
3 (13)
≥7
3 (11.5)
1 (33)
P<0.001
Yes
21 (44.7)
+
N=168
LIC (mg Fe/g dw)
n (%)
No
18 (14.9)
Yes
121 (72)
Yes
103 (85.1)
P=0.020
<7
27 (69.2)
9 (33.3)
≥7
12 (30.8)
7 (58.3)
P=0.016
P<0.001
<7
39 (37.9)
16 (41)
≥7
64 (62.1)
47 (73.4)
P=0.001
Mild phenotype (neither splenectomized nor transfused)
Moderate phenotype (either splenectomized or transfused)
Severe phenotype (both splenectomized and transfused)
Musallam KM et al. Haematologica 2011;96:1605-12.
Association with vascular
disease truly causal? (2)
Mild phenotype (neither splenectomized nor transfused)
Moderate phenotype (either splenectomized or transfused)
1.0
0.8
0.6
*
0.4
0.2
0
**
1.0
LIC < 7 mg Fe/g dry wt
LIC ≥ 7 mg Fe/g dry wt
Probability of
vascular morbidity
Probability of
vascular morbidity
Severe phenotype (both splenectomized and transfused)
**
LIC < 7 mg Fe/g dry wt
LIC ≥ 7 mg Fe/g dry wt
0.8
0.6
0.4
0.2
0
0
10
20
30
40
Age (years)
*p < 0.05; **p < 0.01; ***p < 0.001.
Musallam KM et al. Haematologica 2011;96:1605-12.
50
60
70
0
10
20
30
Age (years)
40
50
60
70
RBC
Hemoglobin
Denaturation
Degradation
Fe++
Excess α-chains
Oxidation
Hemichromes
ROS
PS
PS
FVa, FXa, FII
↓ Protein C & S
Thrombin
Inclusion bodies
Band 3
Spectrin & Band 3
clustering abnormalities
↑ RBC adhesion
& aggregation
Thrombus
formation
Musallam KM et al. Thromb Res 2012;130:695-702.
PS
exposure
Fibrin
↑ Platelet
activation
& adhesion
↑ WBC
activation
Tissue factor, ELAM-1,
ICAM-1, VCAM-1, VWF
Endothelial
damage/activation
Assessment of Iron Overload
● Serum ferritin
● Liver iron concentration
●
SQUID
●
MRI
●
Biopsy
● Cardiac MRI?
● Other markers (NTBI, Transferrin Sat)?
Musallam KM et al. Blood Rev 2012;26:16-9.
Spot Serum Ferritin
Measurement
● Caution with interpreting spot serum ferritin values to
tailor iron chelation therapy in NTDT
● The 1000 and 2500 ng/ml thresholds are used in
thalassemia major patients as they predict survival and
cardiac outcomes -> less relevant in NTDT and no similar
predictive assessment exists
● Although serum ferritin correlates with LIC in NTDT1-4, the
ratio of serum ferritin to LIC is lower relative to patients
with β-thalassemia major1,4-6
1.
2.
3.
4.
5.
6.
Taher A et al. Haematologica 2008;93:1584-6.
Lal A et al. N Engl J Med 2011;364:710-8.
Taher AT et al. Blood 2012;120:970-7.
Pakbaz et al. Pediatr Blood Cancer 2007;49:329-32.
Origa R et al. Haematologica 2007;92:583-8.
Taher AT et al. Am J Hematol 2010;85:288-90.
Serum Ferritin vs. LIC in TI and
TM
Serum ferritin level (μg/L)
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
TI
Linear (TI)
0
5
10
Taher A et al. Haematologica 2008;93:1584-6.
15
TM
Linear (TM)
20
25
30
35
LIC (mg Fe/g dry wt)
40
45
50
Conclusions
● NTDT patients show considerable iron overload despite
their transfusion-independence
● Ineffective erythropoiesis leading to hepcidin suppression
and increased intestinal iron absorption is the primary
implicated mechanism
● Iron overload in this patient population is associated with
morbidities involving several organs and organ systems
● Timely detection is warranted, and caution regarding
serum ferritin level interpretation is essential