The evaluation of carotid intima-media thickness in children with beta-thalassaemia major

Accelerated atherosclerosis in beta-thalassemia

Children with beta-thalassemia (BT) present with an increase in carotid intima-medial thickness, an early sign suggestive of premature atherosclerosis. However, it is unknown if there is a direct relationship between BT and atherosclerotic disease. To evaluate this, wild-type (WT, littermates) and BT (Hbbth3/+) mice, both male and female, were placed on a 3-mo high-fat diet with low-density lipoprotein receptor suppression via overexpression of proprotein convertase subtilisin/kexin type 9 (PCSK9) gain-of-function mutation (D377Y). Mechanistically, we hypothesize that heme-mediated oxidative stress creates a proatherogenic environment in BT because BT is a hemolytic anemia that has increased free heme and exhausted hemopexin, heme's endogenous scavenger, in the vasculature. We evaluated the effect of hemopexin (HPX) therapy, mediated via an adeno-associated virus, to the progression of atherosclerosis in BT and a phenylhydrazine-induced model of intravascular hemolysis. In addition, we evaluated the effect of deferiprone (DFP)-mediated iron chelation in the progression of atherosclerosis in BT mice. Aortic en face and aortic root lesion area analysis revealed elevated plaque accumulation in both male and female BT mice compared with WT mice. Hemopexin therapy was able to decrease plaque accumulation in both BT mice and mice on our phenylhydrazine (PHZ)-induced model of hemolysis. DFP decreased atherosclerosis in BT mice but did not provide an additive benefit to HPX therapy. Our data demonstrate for the first time that the underlying pathophysiology of BT leads to accelerated atherosclerosis and shows that heme contributes to atherosclerotic plaque development in BT.NEW & NOTEWORTHY This work definitively shows for the first time that beta-thalassemia leads to accelerated atherosclerosis. We demonstrated that intravascular hemolysis is a prominent feature in beta-thalassemia and the resulting increases in free heme are mechanistically relevant. Adeno-associated virus (AAV)-hemopexin therapy led to decreased free heme and atherosclerotic plaque area in both beta-thalassemia and phenylhydrazine-treated mice. Deferiprone-mediated iron chelation led to deceased plaque accumulation in beta-thalassemia mice but provided no additive benefit to hemopexin therapy.

Premature Atherosclerosis in Children With Transfusion-Dependent Thalassemia: A Twin-Center Cross-Sectional Study

OBJECTIVE

Objective To analyze the risk of premature atherosclerosis in children with transfusion-dependent thalassemia (TDT) compared to controls by measuring carotid intima-media thickness (CIMT) and correlating it with clinical and biochemical parameters.

METHODS

Case-control study among children aged 2 to 15 years.

RESULTS

Significantly higher CIMT values were observed across all age groups. Mean (SD) CIMT in controls were 0.27(0.07) mm, 0.39 (0.03) mm, and 0.46 (0.05) mm in 2 to 5 years, 6 to 10 years, and 11 to 15 years age groups respectively, as against 0.43 (0.08) mm, 0.55 (0.07) mm and 0.63 (0.08) mm in cases in similar age groups (P<0.001). Mean triglycerides and liver enzymes were significantly elevated in cases. Logistic regression analysis demonstrated that older age group and higher serum ferritin levels, but not dyslipidemia, were significantly associated with high CIMT.

CONCLUSION

Children with TDT are at increased risk for premature atherosclerosis.

The Value of SIRT1/FOXO1 Signaling Pathway in Early Detection of Cardiovascular Risk in Children with β-Thalassemia Major

Background: Atherosclerosis represents one of the major causes of morbidity in children with β-thalassemia major (β-TM). Aim: This study was designed to investigate SIRT1-FOXO1 signaling in β-TM children and their role in early detection of premature atherosclerosis. Methods: We equally subdivided 100 Egyptian children aged 6−14 years with β-TM according to carotid intima media thickness (CIMT) into 50 with CIMT < 0.5 mm and 50 with CIMT ≥ 0.5 mm, and 50 healthy children of matched age were included. They were subjected to evaluation of SIRT1, heat shock protein 72 (HSP72), and hepcidin levels via ELISA and forkhead box protein 1 (FOXO1) mRNA expression using real-time PCR in PBMCs; meanwhile, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase activities were evaluated spectrophotometrically. Results: Our results show significantly high values for CIMT, β-stiffness, atherogenic index of plasma (AIP), MDA, HSP72 and FOXO1, ferritin with significantly low hepcidin, SOD, catalase, and SIRT1 in β-TM as compared to controls with a more significant difference in β-TM with CIMT ≥ 0.5 mm than those with CIMT < 0.5 mm. A significant positive correlation between CIMT and MDA, HSP72, and FOXO1 gene expression was found, while a significant negative correlation with hepcidin, SOD, catalase, and SIRT1 was found. FOXO1 gene expression and HSP72 levels were the strongest independent determinants of CIMT. Conclusion: In β-TM, FOXO1 signaling is activated with low levels of SIRT1, and this is attributed to accelerated atherosclerosis in β-TM, which would be crucial in prediction of atherosclerosis.

Mirror aneurysms of extracranial internal carotid arteries in a patient with beta-thalassemia major

Beta-thalassemia major is a chronic disorder characterised by severe anemia. This patient with beta-thalassemia major is the first magnetic resonance (MR) angiographic case for symmetric mirror aneurysms of the extracranial internal carotid arteries. For diagnosis of vascular complications requires angiographic procedures such as catheter angiography, computed tomography angiography, MR angiography, or Doppler ultrasonography. Time-of-flight MR angiography is a non-invasive useful technique in diagnosis of the aneurysmatic patients.

Sitagliptin on Carotid Intima-Media Thickness in Type 2 Diabetes Mellitus Patients and Anemia: A Subgroup Analysis of the PROLOGUE Study

Introduction

Randomized clinical trials have not shown an additional clinical benefit of sitagliptin treatment over conventional treatment alone. However, studies of sitagliptin treatment have not examined the relationship between anemia and treatment group outcomes.

Methods

The PROLOGUE study is a prospective clinical trial of 442 participants with type 2 diabetes mellitus (T2DM) randomized to sitagliptin treatment or conventional treatment which showed no treatment differences [Estimated mean (± standard error) common carotid intima-media thickness (CIMT) was 0.827 ± 0.007 mm and 0.837 ± 0.007 mm, respectively, with a mean difference of -0.009 mm (97.2% CI −0.028 to 0.011, p = 0.309) at 24 mo of follow-up]. This is a post hoc subanalysis using data obtained from the PROLOGUE study; the study population was divided into anemic groups (n = 94) and nonanemic group (n = 343) based on hemoglobin level. And we analyzed for the changes in each CIMT parameter from baseline to 24 months in subgroups.

Results

The treatment group difference in baseline-adjusted mean common carotid artery- (CCA-) IMT at 24 months was −0.003 mm (95% CI −0.022 to 0.015, p = 0.718) in the nonanemic subgroup and −0.007 mm (95% CI −0.043 to 0.030, p = 0.724) in the anemic subgroup. Although there were no significant differences in the other CIMT parameters between the treatment groups in the anemic subgroup, the changes in mean and max ICA-IMT at 24 months in the nonanemic subgroup were significantly lower in the sitagliptin group than the conventional group [−0.104 mm (95% CI −0.182 to −0.026), p = 0.009 and −0.142 mm (−0.252 to −0.033), p = 0.011, respectively].

Conclusion

These data suggest that nonanemia may indicate a potentially large subgroup of those with T2DM patients that sitagliptin therapy has a better antiatherosclerotic effect than conventional therapy. Further research is needed to confirm these preliminary observations.

Carotid Doppler ultrasonography as a screening tool of early atherosclerotic changes in children and young adults with β-thalassemia major

PURPOSE

β-thalassemia major (β-TM) patients had an increased incidence of cardiovascular complications secondary to iron overload. They showed early carotid atherosclerosis as showed by increased carotid intima media thickness (CIMT) that may occur early even when significant iron overload is absent. We aimed to test the diagnostic performance of CIMT measurement by Doppler ultrasonography as a structural indicator for premature atherosclerosis in β-TM patients.

METHODS

Case-control study included 42 β-TM patients (24 males and 18 females) aged from 3 to 30 years and 36 age- and sex-matched healthy controls. Carotid Duplex was used for measurement of CIMT in all subjects.

RESULTS

The frequency of abnormal CIMT among patients was 19%. Mean CIMT of right anterior wall was 0.8 ± 0.16 (range 0.5-1.2) mm, of right posterior wall was 0.80 ± 0.17 (range 0.5-1.2), of right lateral wall was 0.8 ± 0.17 (range 0.5-1.1) mm. CIMT of left anterior wall ranged from 0.5 to 1.2 with mean 0.81 ± 0.17, CIMT of left posterior wall ranged from 0.5 to 1.1 with mean 0.80 ± 0.17 mm. Mean CIMT of left lateral wall was 0.81 ± 0.18 mm (range 0.5-1.2). CIMT of right anterior, right posterior and left anterior walls were thicker in patients compared to controls (P = 0.003, 0.015, < 0.001, respectively). There was no observable difference in CIMT between males and females, splenectomised and non-splenectomised, or well and poorly chelated subgroups (P > 0.05). CIMT of right lateral wall correlated with the disease duration (r = 0.3, P = 0.04).

CONCLUSIONS

Carotid ultrasound was a useful tool to detect subclinical atherosclerosis thorough CIMT evaluation in B-thalassemia major patients. B-thalassemia major children proved to have an increased CIMT regardless the state of iron overload.

The relation between hemoglobin variability and carotid intima-media thickness in chronic hemodialysis patients

PURPOSE

Hemoglobin variability is a common problem among hemodialysis patients. We have previously demonstrated an association between Hb variability and left ventricular mass index. In this study, we investigated a possible relation between Hb variability and carotid intima-media thickness (CIMT).

METHODS

Twelve-month hemoglobin (Hb) values of 135 patients on maintenance hemodialysis were examined retrospectively. The range of 11-12 gr/dl was accepted as normal according to the KDOQI guidelines. Hemoglobin levels were classified as: Hb < 11 gr/dl:Low, Hb = 11-12 gr/dl:Normal and Hb > 12 gr/dl:High. According to 12-month Hb trajectory, the patients were divided into three groups: low-normal (LN), normal-high (NH) and low-high (LH). The CIMT measurements were taken on common carotid arteries bilaterally, and the average of these measurements were taken. The groups were compared in terms of CIMT measurements, demographic and laboratory features.

RESULTS

The LN, NH and LH groups were similar in terms of age, gender, incidence of diabetes mellitus, hypertension and cardiovascular diseases. Duration of hemodialysis, hemodialysis adequacy, serum lipids and CaxP products were also similar among the groups. The mean CIMT value was 0.601 ± 0.107, 0.744 ± 0.139 and 0.604 ± 0.134 mm in the LN, LH and NH groups, respectively (p < 0.001). CIMT was significantly higher in LH than in the other two groups.

CONCLUSIONS

In our study, when the three groups with similar risk factors for atherosclerosis were examined, we found that the LH group with the highest hemoglobin variability has the highest CIMT. This study is the first study to demonstrate that Hb variability is associated with an increase in CIMT in HD patients.

Carotid Intima-Media Thickness and Oxidative Stress Markers for Assessment of Atherosclerosis in Children with β Thalassemia Major

The present study evaluates carotid intimamedia thickness (CIMT) in children with β thalassemia major to assess atherosclerosis and its relation to the underlying proposed causative mechanisms via lipid peroxidation product malondialdehyde (MDA), oxidized lowdensity lipoproteins (LDL), total antioxidant level, and lipid profile. A cross sectional study was conducted on 62 children (31 cases and 31 controls). CIMT by high resolution ultrasound and biochemical parameters i.e., total cholesterol, triglycerides, high-density lipoproteins, LDL, Oxidized LDL, lipoprotein (a), lipid peroxidation product MDA and total antioxidant were measured in enrolled subjects and compared. In our study, CIMT was significantly increased in β thalassemia major patients’ as compared to healthy controls. Mean CIMT in cases was 0.69 ± 0.11 mm and in controls 0.51 ± 0.07 mm. Mean oxidized LDL (EU/mL) in cases 39.3 ± 34.4 (range 14.4 to 160) was significantly raised (p = 0.02, t test) as compared to controls 23.9 ± 13.4 (range 12 to 70). In our study we found MDA levels (nmol/mL) to be increased in β thalassemia patients as compared to controls. Mean MDA was 10.0 ± 3.27 (4.41 to 17.48) in cases while in controls was 6.87 ± 4.55 (1.5 to 17.9). Our study results show CIMT as an early marker of atherogenesis in β thalassemia major. Oxidative stress markers are also increased in β thalassemia major patients and lipoprotein (a) shows a positive correlation with CIMT. The present study points towards various atherogenetic mechanisms in β thalassemia major.

Deferoxamine stimulates LDLR expression and LDL uptake in HepG2 cells

SCOPE

Iron overload contributes to the pathogenesis of atherosclerosis and iron chelators are beneficial through their antioxidant properties. Hepatic iron loading increases cholesterol synthesis. Whether iron depletion could affect hepatic cholesterol metabolism is unknown.

METHODS AND RESULTS

We examined the effect of the iron chelator deferoxamine (DFO) on mRNA expression of genes involved in cholesterol metabolism and/or cholesterol uptake. Our results revealed that DFO increases LDL receptor (LDLR) mRNA levels in human hepatocyte-derived cell lines HepG2 and Huh7 cells, and in K562 cells. In HepG2 cells, we observed that DFO increases (i) LDLR-mRNA levels in a time- and dose-dependent manner, (ii) LDLR-protein levels; (iii) cell surface LDLR; and (iv) LDL uptake. In contrast, the mRNA levels of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, sterol regulatory element-binding proteins, and the mRNA/protein levels of proprotein convertase subtilisin-kexin 9 were not modulated by DFO, suggesting that the LDLR regulation by DFO is not at the transcriptional or posttranslational levels. Since LDLR-mRNA was stabilized by DFO, a posttranscriptional mechanism is suggested for the DFO-mediated upregulation of LDLR.

CONCLUSION

DFO induced an increase in LDLR expression by a posttranscriptional mechanism resulting in an enhancement of LDL uptake in HepG2 cells, suggesting increased LDLR activity as one of the underlying causes of the hypocholesterolemic effect of iron reduction.

Serum Ferritin Relates to Carotid Intima-Media Thickness in Offspring of Fathers With Higher Serum Ferritin Levels

OBJECTIVE

Body iron status has been linked to atherosclerosis in adults. The purposes of our study were to determine (1) the association between circulating ferritin levels and carotid intima-media thickness (cIMT) in a cohort of apparently healthy children and (2) the association between cIMT and parental ferritin levels.

APPROACH AND RESULTS

Circulating ferritin levels (microparticle enzyme immunoassay), metabolic parameters, and cIMT (ultrasonography) were analyzed cross-sectionally in a cohort of 692 healthy white children with a mean age of 8 ± 2 years (52% girls and 48% boys). In consecutive 123 children from the cross-sectional sample, the same serum assessments were also performed at baseline in their parents, and the cIMT was repeated after 3 years of follow-up in the children at a mean age of 11 ± 2 years (53% girls and 47% boys). Weak but significant positive associations were evident between children's circulating ferritin levels and cIMT (r=0.123; P=0.001) and with the change in cIMT 3 years later a tendency was also observed (r=0.185; P=0.048). In multiple regression analyses, circulating ferritin levels contributed independently to cIMT variance (β=0.090; P=0.026; R(2)=10%) and cIMT change variance (β=0.216; P=0.019; R(2)= 3.4%) after controlling for body mass index, high-sensitivity C-reactive protein, age, sex, and low-density lipoprotein-cholesterol levels. This association was, however, remarkably significant (β=0.509; P=0.001; R(2)= 20.4%) in children whose fathers had ferritin levels above the median value (122.5 ng/mL).The latter association remained significant after correction for multiple testing. Maternal's ferritin levels showed no interaction in this association.

CONCLUSIONS

These results suggest a paternal-specific effect on cIMT partially reflected by father's ferritin levels.

Carotid endarterectomy in a young symptomatic patient with B-thalassemia major

β-Thalassemia major promotes atherosclerotic process, although the debating literature concerning the lipidic profile of young patients; it is well accepted that there is early vascular destruction in these homozygous patients either as a direct consequence of the genetic disorder per se or because of the repeated transfusions and the iron overload. Despite the potential of the disease for local brain thrombotic events, accelerated atheromatosis can lead to early thromboembolic events. We present an interesting case of a 36-year-old man with unilateral embolic infarcts (repeated transient ischemic attacks) originated from a near occlusion right carotid stenosis with additional peripheral thrombus. The patient underwent a successful carotid endarterectomy with primary arterial closure with uneventful postoperative course, confirmed by a clear postoperative angiography; he remains asymptomatic 18 months later. To the best of our knowledge, this is the first case of a young symptomatic patient with β-thalassemia major who underwent carotid repair.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) and tumor necrosis factor-alpha (TNF-α) and their relation to premature atherosclerosis in β-thalassemia children

BACKGROUND/OBJECTIVES

Beta (β)-thalassemia adults are prone to premature atherosclerosis but data about this complication among thalassemia children are few. Lipoprotein-associated phospholipase A2 (Lp-PLA2) and tumor necrosis factor-α (TNF-α) are inflammatory markers that could be implicated in atherosclerotic process. We investigated Lp-PLA2 and TNF-α levels in β-thalassemia children and their relation to subclinical atherosclerosis.

METHODS

Twenty-two β-thalassemia major (TM), 20 β-thalassemia intermedia children, and 30 age- and sex-matched healthy controls were included. Lipid profile (by colorimetric assay), serum ferritin, TNF-α, and plasma Lp-PLA2 levels (by enzyme-linked immunosorbent assay technique) were estimated. Carotid intima-media thickness (cIMT) was measured by high-resolution ultrasound.

RESULTS

Both patient groups exhibited anti-atherogenic lipid profile except increased serum triglycerides. They had significantly higher plasma Lp-PLA2 and serum TNF-α compared to the controls (P < 0.001). Elevated cIMT was documented in 57% of the thalassemia children and was higher among hepatitis C (HCV) positive patients. Serum ferritin, TNF-α, and plasma Lp-PLA2 levels were significantly higher in patients with premature atherosclerosis. cIMT correlated significantly with serum ferritin, TNF-α, and plasma Lp-PLA2 in both patient groups. Among TM children, serum ferritin had significant positive correlation with serum TNF-α and plasma Lp-PLA2. The elevation of both markers was not related to HCV infection.

CONCLUSIONS

Premature atherosclerosis is common among young thalassemia children. Lp-PLA2 and TNF-α are significantly increased in thalassemia children and show strong correlations with cIMT, suggesting that both of them may be appreciated as modulating factors in carotid atherosclerosis pathophysiological process among these children.