Brain perfusion changes in beta-thalassemia.

BACKGROUND: Brain injury in hereditary hemoglobinopathies is commonly attributed to anemia-related relative hypoperfusion in terms of impaired oxygen blood supply. Supratentorial and infratentorial vascular watershed regions seem to be especially vulnerable, but data are very scarce. AIMS: We investigated a large beta-thalassemia sample with arterial spin labeling in order to characterize regional perfusion changes and their correlation with phenotype and anemia severity. METHODS: We performed a multicenter single-scanner cross-sectional 3T-MRI study analyzing non-invasively the brain perfusion in 54 transfusion-dependent thalassemia (TDT), 23 non-transfusion-dependent thalassemia (NTDT) patients and 56 Healthy Controls (HC). Age, hemoglobin levels, and cognitive functioning were recorded. RESULTS: Both TDT and NTDT patients showed globally increased brain perfusion values compared to healthy controls, while no difference was found between patient subgroups. Using age and sex as covariates and scaling the perfusion maps for the global cerebral blood flow, beta-thalassemia patients showed relative hyperperfusion in supratentorial/infratentorial watershed regions. Perfusion changes correlated with hemoglobin levels (p = 0.013) and were not observed in the less severely anemic patients (hemoglobin level > 9.5 g/dL). In the hyperperfused regions, white matter density was significantly decreased (p = 0.0003) in both patient subgroups vs. HC. In NTDT, white matter density changes correlated inversely with full-scale Intelligence Quotient (p = 0.007) while in TDT no correlation was found. CONCLUSION: Relative hyperperfusion of watershed territories represents a hemodynamic hallmark of beta-thalassemia anemia challenging previous hypotheses of brain injury in hereditary anemias. A careful management of anemia severity might be crucial for preventing structural white matter changes and subsequent long-term cognitive impairment.

ß-Thalassemia minor & renal tubular dysfunction: is there any association?

OBJECTIVE: Beta(ß)-thalassemia is one of the most common hereditary hematologic disorders. Patients with thalassemia minor (TM) are often asymptomatic and the rate of renal dysfunction is unknown in these patients. Due to the high prevalence of renal dysfunction in Iran, the current study aimed to determine renal tubular dysfunction in patients with beta-TM. METHODS: In this case-control study, 40 patients with TM and 20 healthy subjects were enrolled and urinary and blood biochemical analysis was done on their samples. Renal tubular function indices were determined and compared in both groups. Data was analyzed by SPSS software, version 20.0. RESULTS: The fraction excretion (FE) of uric acid was 8.31 ± 3.98% in the case and 6.2 ± 34.71% in the control group (p = 0.048). Also, FE of potassium was significantly higher in patients with TM (3.22 ± 3.13 vs. 1.91 ± 0.81; p = 0.036). The mean Plasma NGAL level was 133.78 ± 120.28 ng/mL in patients with thalassemia and 84.55 ± 45.50 ng/mL in the control group (p = 0.083). At least one parameter of tubular dysfunction was found in 45% of patients with thalassemia. CONCLUSION: Based on the results of this study, the prevalence of tubular dysfunction in beta-thalassemia minor patients is high. Due to the lack of knowledge of patients about this disorder, periodic evaluation of renal function in TM patients can prevent renal failure by early diagnosis.

Renal function in ß-thalassemia major patients treated with two different iron-chelation regimes.

BACKGROUND: Renal injury in transfusion dependent ß thalassemia patients (TDT) has been attributed to iron overload, chronic anemia and iron-chelation therapy (ICT) toxicity. We studied renal function in TDT patients treated with two different ICT regimes. PATIENTS AND METHODS: We studied 36 TDT patients: 26 received deferasirox (DFX) and 10 were treated with deferoxamine (DFO) +/- deferiprone (DFP). RESULTS: Increased uNAG was found in 30% of the DFX group vs. 10% of the DFO+/-DFP group, the mean uNAG level in the DFX group was significantly higher than in the DFO+/-DFP group, (P < 0.05). A moderate negative correlation was found between uNAG levels and mean serum ferritin for the prior 10 years (P = 0.03), more pronounced for the DFO+/-DFP group. Twenty nine patients had had their renal function evaluated 10 years earlier; eGFR significantly declined in patients switched to DFX (P = 0.0093) but not in patients who continued DFO+/-DFP. CONCLUSIONS: A high prevalence of renal tubular damage was observed in our TDT patients, particularly those treated with DFX; uNAG was negatively associated with mean 10-year serum ferritin, suggesting ICT's involvement in tubular injury. A significant decline in eGFR compared to a decade earlier was observed only in patients currently treated with DFX. Strict follow-up of renal function in TDT patients is warranted.

Longitudinal study of glomerular hyperfiltration and normalization of estimated glomerular filtration in adults with sickle cell disease.

Glomerular hyperfiltration is common in sickle cell disease (SCD) and precedes proteinuria and declining kidney function. We evaluated hyperfiltration in SCD patients and its "normalization." Routine visit data were collected retrospectively from adult SCD patients in a single centre from 2004 to 2013. Baseline was defined as first available serum creatinine and hyperfiltration as estimated glomerular filtration rates (eGFR) >130 ml/min/1·73 m2 for women and >140 ml/min/1·73 m2 for men. Normalization of hyperfiltration was eGFR reduction to 90-130 ml/min/1·73 m2 for women or 90-140 ml/min/1·73 m2 for men. Among 292 patients, median age was 27 years [interquartile range (IQR):20·0-38·0], and 56·8% had baseline hyperfiltration. Baseline hyperfiltration was inversely associated with age [odds ratio (OR):0·86, 95% confidence interval (CI): 0·82-0·90; P < 0·0001], male sex (OR:0·16, 95% CI: 0·07-0·41; P = 0·0001), haemoglobin (OR:0·76, 95% CI 0·61-0·94; P = 0·01), weight (OR:0·96, 95% CI: 0·93-0·99; P = 0·004), and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE-I/ARB) use (OR:0·08, 95% CI: 0·01-0·75; P = 0·03), and positively with hydroxycarbamide use (OR:2·99, 95% CI: 1·18-7·56; P = 0·02). Of 89 hyperfiltration patients without baseline proteinuria, 10 (11·2%) developed new-onset proteinuria [median 1·05 years (IQR:0·63-2·09)]. Normalization of hyperfiltration was less likely with higher baseline eGFR [hazard ratio (HR):0·90, 95% CI: 0·86-0·95; P < 0·0001] and more likely in males (HR:6·35, 95% CI:2·71-14·86, <0·0001). Hyperfiltration is common in adult SCD patients, particularly when younger. Decline to normal values is more likely in males, possibly representing kidney function loss rather than improvement in hyperfiltration.

Ineffective Erythropoiesis in ß-Thalassaemia: Key Steps and Therapeutic Options by Drugs.

ß-thalassaemia is a rare genetic condition caused by mutations in the ß-globin gene that result in severe iron-loading anaemia, maintained by a detrimental state of ineffective erythropoiesis (IE). The role of multiple mechanisms involved in the pathophysiology of the disease has been recently unravelled. The unbalanced production of α-globin is a major source of oxidative stress and membrane damage in red blood cells (RBC). In addition, IE is tightly linked to iron metabolism dysregulation, and the relevance of new players of this pathway, i.e., hepcidin, erythroferrone, matriptase-2, among others, has emerged. Advances have been made in understanding the balance between proliferation and maturation of erythroid precursors and the role of specific factors in this process, such as members of the TGF-ß superfamily, and their downstream effectors, or the transcription factor GATA1. The increasing understanding of IE allowed for the development of a broad set of potential therapeutic options beyond the current standard of care. Many candidates of disease-modifying drugs are currently under clinical investigation, targeting the regulation of iron metabolism, the production of foetal haemoglobin, the maturation process, or the energetic balance and membrane stability of RBC. Overall, they provide tools and evidence for multiple and synergistic approaches that are effectively moving clinical research in ß-thalassaemia from bench to bedside.

Digital thermography and vascular involvement in ß-thalassemia intermedia.

Beta-thalassemia intermedia (ß-TI) is associated with vascular dysfunction. We used digital thermal monitoring (DTM), a non-invasive tool that evaluates vascular function based on changes in fingertip temperature during and after cuff occlusion on ß-TI patients. Thirty-three patients (18 years and older) were recruited in this study and divided into 3 groups: thalassemia, anemic controls, and healthy controls. Exclusion criteria included factors that are known to be associated with vascular damage. Patients underwent DTM and results were extracted as vascular reactivity index (VRI), a measure of how well the circulatory system responds to stimuli that require adjustments of blood flow. One-way analysis of variance (ANOVA) was used to test the mean difference in VRI between the 3 groups. A multiple linear regression was also carried out with VRI as the outcome of interest and a function of covariates that were thought to be of clinical relevance to VRI. The frequency, mean VRI ± standard error (SE) for the thalassemic group were (N = 16), mean = 2.243 ± 0.111; for anemic controls (N = 9), mean = 2.374 ± 0.162; and for the controls (N = 8), mean = 2.338 ± 0.092. ANOVA test indicated a non-significant difference in mean VRI between the three groups (P value = 0.731). Multiple linear regression couldn't detect any significant association between VRI and any of the predictors including the groups. Our study did not show a significant difference in VRI between the 3 study groups. Prospective studies of larger sample size are warranted to establish DTM as a possible non-invasive tool used to evaluate vascular function in ß-TI patients.

Erythrocyte transfusion restored heart rate variability in children with thalassemia major.

Thalassemia major (TM) is a severe transfusion-dependent anemia. Regular erytrocyte transfusion is required for the treatment of thalassemia patients. However, repeated transfusion may result in impairements in heart function. In this study, we aimed to investigate short-term effects of erythrocyte transfusion on autonomic control of heart in children with thalassemia major. For that purpose heart rate variability (HRV), which is a non-invasive method used to evaluate the effects of the autonomic nervous system on the heart rhythym, was measured before and after erythrocyte transfusion and compared to the healthy controls. Children diagnosed with TM (n = 17) and sex and age matched healthy children (HC, n = 30) were included in the study. HRV values of TM patients were measured 5 min before erythrocyte transfusion (BET, n = 17) and 5 min after erythrocyte transfusion (AET, n = 17). Parameters of time-domain and frequency-domain of HRV were evaluated in all participants. Heart rate (HR) was higher in the BET than AET (P = 0.002) but there was no difference between AET and HC groups (P > 0.05). HRV parameters were lower in BET than AET (P < 0.05) but there were no statistical difference between AET and HC (P> 0.05). The data suggest that, in thalassemia major patients, erythrocyte transfusion restores HR and HRV parameters to the levels observed in healthy controls and, thus, in short-terms, appears to be beneficial for the autonomic control of the heart.

Impact of short stature on quality of life: A systematic literature review.

OBJECTIVE: We sought to obtain a better understanding of the burden of short stature using a systematic literature review. METHODS: Studies of the burden of short stature, of any cause in adults and children, were searched using Embase, MEDLINE and Cochrane databases in April 2020, capturing publications from 2008 onwards. Case series and populations with adult-onset growth hormone deficiency (GHD) were excluded. RESULTS: Of 1684 publications identified, 41 studies (33 in children, 8 in adults) were included. All studies assessed human burden. Most study populations in children included short stature due to GHD, idiopathic short stature (ISS) and short stature after being born small for gestational age (SGA). In these populations, four studies showed that quality of life (QoL) in children with short stature was significantly worse than in children with normal stature. A significant association between QoL and short stature was observed in children with chronic kidney disease (CKD) (3 studies), achondroplasia (1 study) and transfusion-dependent ß-thalassaemia (1 study), and in samples with mixed causes of short stature (3 studies). Three studies (one in GHD/ISS/SGA and two in CKD) found no significant association between short stature and QoL, and several studies did not report statistical significance. Approximately half of adult studies showed that QoL was reduced with short stature, and the other half showed no association. Two studies, one in adults with Prader-Willi syndrome and one in children with GHD, suggested a potential association between short stature and poorer cognitive outcomes. Three studies demonstrated an increased caregiver burden in parents of children with short stature. CONCLUSIONS: Evidence suggests that, compared with those with normal stature, children and adults with short stature of any cause may experience poorer QoL. Further research could extend our understanding of the human burden in this field.

SLN124, a GalNac-siRNA targeting transmembrane serine protease 6, in combination with deferiprone therapy reduces ineffective erythropoiesis and hepatic iron-overload in a mouse model of ß-thalassaemia.

Beta-thalassaemia is an inherited blood disorder characterised by ineffective erythropoiesis and anaemia. Consequently, hepcidin expression is reduced resulting in increased iron absorption and primary iron overload. Hepcidin is under the negative control of transmembrane serine protease 6 (TMPRSS6) via cleavage of haemojuvelin (HJV), a co-receptor for the bone morphogenetic protein (BMP)-mothers against decapentaplegic homologue (SMAD) signalling pathway. Considering the central role of the TMPRSS6/HJV/hepcidin axis in iron homeostasis, the inhibition of TMPRSS6 expression represents a promising therapeutic strategy to increase hepcidin production and ameliorate anaemia and iron overload in ß-thalassaemia. In the present study, we investigated a small interfering RNA (siRNA) conjugate optimised for hepatic targeting of Tmprss6 (SLN124) in ß-thalassaemia mice (Hbbth3/+ ). Two subcutaneous injections of SLN124 (3 mg/kg) were sufficient to normalise hepcidin expression and reduce anaemia. We also observed a significant improvement in erythroid maturation, which was associated with a significant reduction in splenomegaly. Treatment with the iron chelator, deferiprone (DFP), did not impact any of the erythroid parameters. However, the combination of SLN124 with DFP was more effective in reducing hepatic iron overload than either treatment alone. Collectively, we show that the combination therapy can ameliorate several disease symptoms associated with chronic anaemia and iron overload, and therefore represents a promising pharmacological modality for the treatment of ß-thalassaemia and related disorders.

Drug safety in thalassemia: lessons from the present and directions for the future.

Introduction: Beta-thalassemia is an autosomal recessive hereditary anemia characterized by reduced or absent ß-globin chain synthesis, affecting about 60,000 people peryear. Management for ß-thalassemia major includes regular blood transfusions followed by iron chelating therapy and drug targeting ineffective erythropoiesis.Areas covered: The safety of licensed drugs for the management of ß-thalassemia is reviewed, using evidence from clinical trials and observational research. Such drugs include the iron chelators and the erythrocyte maturation agent luspatercept. The safety of emerging treatment, such as hydroxyurea and thalidomide is also reviewed.Expert opinion: Beta-thalassemia is arare disease, and is not surprising that there are limited studies investigating the safety of drugs used in this disease. Indeed, although observational studies are the main source of drug safety information in areal-world setting, only eleven studies were identified for iron-chelators and none of these estimated the risk of agiven safety outcome. Future work should aim to better leverage existing sources of real-world datato investigate drug safety in thalassemia.

[Research progress of iron metabolism in phenotype modification of ß-thalassemia].

ß-thalassemia is a type of inherited hemolytic anemia caused by decreased globin production due to defect of the HBB gene. The pathogenesis of the disease is imbalance of α/ß globin chains. The excess of α-globin chains will form hemichromes which can damage red blood cell membranes and lead to hemolysis, ineffective erythropoiesis, and secondary iron overload. Iron overload in turn can cause complications such as growth retardation, liver cirrhosis, cardiac insufficiency, and aggravate the disease phenotype. In recent decades, genes participating in iron metabolism have been discovered, and the mechanism of iron metabolism in the development of thalassemia has gradually been elucidated. Subsequently, by manipulating the expression of key genes in iron metabolism such as hepcidin and transferrin receptor, researchers have revealed that iron restriction can improve ineffective hematopoiesis and iron overload, which may provide a potential approach for the treatment of thalassemia. This article reviews the progress of research on iron metabolism-related genes and related pathways in ß-thalassemia.

Correlation between Serum Fatty Acid Binding Protein 4 (FABP4) Levels and Cardiac Function in Patients with Thalassemia Major.

BACKGROUND: Patients with thalassemia major may suffer from complications due to iron overload. It has been suggested that several adipokines may play a potential role in the development of complications in thalassemia. Fatty acid-binding protein 4 (FABP4) is one of the adipokines, bridging several aspects of metabolic and inflammatory pathways. Little is known about the relationship between this adipokine and cardiac and liver function, especially in patients with thalassemia major. AIMS: This study is aimed at determining serum FABP4 levels in patients with thalassemia major and whether its concentration correlated with serum ferritin levels, as well as cardiac and liver function. METHODS: Thalassemia major outpatients (n = 48) completed laboratory examination, echocardiography, and electrocardiography. RESULTS: The mean age was 21.9 ± 8.0 years. A negative and weak correlation between serum ferritin and FABP4 was observed (r = -0.291, p < 0.05). In addition, there was moderate and positive correlation between left atrial volume index (LAVI) and FABP4 (r = 0.316, p < 0.05). CONCLUSIONS: Serum FABP4 correlated with serum ferritin and cardiac function in patients with thalassemia major. FABP4 may be a potential clinical biomarker for cardiac dysfunction via metabolic and inflammatory pathways due to iron accumulation and toxicity in patients with thalassemia major.

Assessment of ventricular dysfunction in Egyptian children with Beta-thalassemia major.

OBJECTIVE/BACKGROUND: The purpose of this study was to evaluate serum cardiac troponin I and serum N-terminal (NT) pro-brain natriuretic peptide (pro-BNP) levels and the utility of tissue Doppler imaging in assessing cardiovascular changes following left ventricular (LV) dysfunction in children with beta-thalassemia major (ß-TM). In children with ß-TM who depend on regular blood transfusion, cardiac iron toxicity is a common serious complication. The most common cause of death among these patients is congestive heart failure. METHODS: This is a cross-sectional study which included 50 patients with ß-TM and 50 healthy controls. Tissue Doppler imaging was performed and levels of serum ferritin, cardiac troponin I, and NT pro-BNP were estimated for all included patients. RESULTS: Serum NT pro-BNP and cardiac troponin (cTnI) showed a significant increase in patients with ß-TM (p < .001). In patients with ß-TM, LV dimensions (LV end systolic diameter) and (LV end diastolic diameter) were large (p < .01); LV mass (p < .01), E wave, and E/A ratio (p < .01) were high (p < .05); and deceleration time was short (p < .05). Besides, transmitral ratio (E/Em) (p < .05) and tricuspid valve velocity were higher (p < .05), and early diastolic velocity (Em) (p < .05) and systolic wave velocity (Sm) were lower in patients with ß-TM (p < .05). A significant positive correlation was detected between the pro-BNP and E wave (r = 0.558, p < .001), E/A ratio (r = 0.403, p < .001), E/Em ratio (r = 0.576, p < .001), and ferritin (r = 0.545, p < .001). CONCLUSION: Pulsed wave tissue Doppler imaging and NT pro-BNP had a significant role in the estimation of ventricular dysfunction in children with ß-TM.

Research progress of iron metabolism in phenotype modification of β-thalassemia / 中华医学遗传学杂志

β-thalassemia is a type of inherited hemolytic anemia caused by decreased globin production due to defect of the HBB gene. The pathogenesis of the disease is imbalance of α/β globin chains. The excess of α-globin chains will form hemichromes which can damage red blood cell membranes and lead to hemolysis, ineffective erythropoiesis, and secondary iron overload. Iron overload in turn can cause complications such as growth retardation, liver cirrhosis, cardiac insufficiency, and aggravate the disease phenotype. In recent decades, genes participating in iron metabolism have been discovered, and the mechanism of iron metabolism in the development of thalassemia has gradually been elucidated. Subsequently, by manipulating the expression of key genes in iron metabolism such as hepcidin and transferrin receptor, researchers have revealed that iron restriction can improve ineffective hematopoiesis and iron overload, which may provide a potential approach for the treatment of thalassemia. This article reviews the progress of research on iron metabolism-related genes and related pathways in β-thalassemia.

Association between Serum Vitamin D Level and Echocardiographic Abnormalities in Patients with Thalassemia Major.

OBJECTIVES: Thalassemia major (TM) is one of the most common blood disorders with a high mortality rate due to cardiovascular disease. Vitamin D deficiency has been suggested to implicate in cardiac abnormalities. In this prospective study, we aimed to investigate the relationship between serum levels of vitamin D and tissue Doppler (TD) echocardiographic indices in thalassemia major patients. METHODS: A total of 81 TM patients, including 56 females and 25 males, with a mean age of 27.5± 6.8 years, were enrolled consecutively. Serum levels of vitamin D and other biomedical parameters were measured. Then, all patients were subjected to TD echocardiography. Correlations between the serum parameters and systolic and diastolic indices were examined. RESULTS: The serum level of vitamin D was correlated with systolic and diastolic indices such as the EF (r= 0.33, P= 0.003) and TD Imaging (TDI)-lateral (r= 0.31, P= 0.005). However, no correlations were observed between vitamin D deficiency and the LV septal and posterior wall thickness, TDIseptal, tricuspid regurgitation peak gradient (TRPG), pulmonary artery systolic pressure (PASP), deceleration time (DT), and propagation velocity (PVcm/s) indices. The results revealed also no linear correlations between serum vitamin D and albumin (r= -0.17, P= 0.06), ALP (r= -0.12, P= 0.14), T4 (r= -0.11, P= 0.16), as well as TSH (r= -0.10, P= 0.19). CONCLUSION: It seems that vitamin D deficiency in patients with TM is associated with systolic but not diastolic dysfunctions, possibly as consequences of related biochemical abnormalities.

Cardiac Iron Overload by MRI in Children With B-Thalassemia Major and its Correlation With Cardiac Function by Echocardiography.

BACKGROUND: Serial echocardiography is strongly recommended in asymptomatic B-thalassemia major (TM) patients for early detection of subtle cardiac dysfunction. T2*magnetic resonance imaging (MRI) is a noninvasive measurement of myocardial iron burden. Yet, it is not always available in many centers. Our study aimed to evaluate the myocardial function in TM patients using different echocardiographic modalities and to correlate these findings with cardiac T2*MRI. PATIENTS AND METHODS: This is a cross-sectional study that was carried out on 140 children with a mean age of 10.9±3.7 years. One hundred children with TM and 40 healthy children were matched for age and sex as a control group. Serum ferritin, serum iron, and iron-binding capacity were measured. Cardiac iron overload was assessed by T2*MRI and cardiac function was assessed by echocardiography. The local ethics committee approved the study. RESULTS: Among 100 children with TM, only 32% had cardiac iron overload of 8.525±5.45 detected by cardiac T2*MRI. Iron deposition correlated significantly with age. Markers of iron overload were significantly correlated with cardiac T2*MRI. There were significantly lower values of myocardial performance index, longitudinal strain, circumferential strain, area strain, and radial strain in TM patients compared with the controls (P<0.001). Only the myocardial performance index was correlated with T2*MRI. CONCLUSIONS: This study confirms that some parameters measured by tissue Doppler imaging such as the myocardial performance index could be useful for the early detection of cardiac impairment in asymptomatic TM patients when cardiac MRI is lacking. Further studies on a large scale to identify other parameters with high sensitivity are recommended.