Renal function in pediatric patients with beta-thalassemia major

Renal Findings in Patients with Thalassemia at Abdominal Ultrasound: Should We Still Talk about "Incidentalomas"? Results of a Long-Term Follow-Up

We retrospectively collected all ultrasound imaging data of our thalassemia patients over a period of 10 years with the aim of assessing the prevalence and the risk factors of renal stones and cysts. Moreover, we assessed the incidence of renal-cell carcinoma (RCC) among thalassemia patients (133 with thalassemia major (TM) and 157 with thalassemia intermedia (TI)) and its association with demographic and clinical findings. Renal stones were detected in 15.2% of patients. In the multivariable Cox regression analysis, the independent predictors were blood consumption, splenectomy, and proteinuria. Renal cysts were detected in 18.4% of patients. In the multivariable analysis, age emerged as the only independent predictor. After the first detection, 35% of the patients showed changes in the number, size, or grading of renal cysts. During the study period, the crude incidence rate of RCC was 75.9 cases per 100,000 person-years. The most frequent histological subtype (80%) included clear-cell RCC. In total, 80% of patients with RCC had TM and all were positive for hepatitis C virus antibodies. Thalassemia patients are significantly affected by asymptomatic renal diseases such as stones, cysts, and cancer, suggesting the need for regular screening by imaging.

The Evaluation of Renal Iron Deposition With a 3 Tesla MRI Device in Beta-Thalassemia Major Patients

Background and objective Beta-thalassemia is the most frequent monogenic disease in the world. In beta-thalassemia major (BTM) patients, blood transfusions for severe anemia usually cause iron overload, leading to increased morbidity and mortality. In this study, we aimed to examine the iron overload in the kidneys of BTM patients with a 3 Tesla (3T) MRI device and assess the relationship between iron overload in the liver and heart as well as serum ferritin levels. Methods This was a retrospective study covering the period between November 2014 and March 2015. MRI was performed on 21 patients with BTM who were receiving blood transfusions and chelation therapy. The control group (n=11) included healthy volunteers. A 3T MRI device (Ingenia, Philips, Best, The Netherlands) using a 16-channel phased array SENSE-compatible torso coil was used. Three-point DIXON (mDIXON) sequence and the relaxometry method were employed to measure iron overload. Both kidneys were analyzed via mDIXON sequence for atrophy or variations. Afterward, the images in which renal parenchyma could be distinguished best were selected. Iron deposition was analyzed via the relaxometry method using a unique software (CMR Tools, London, UK). All data were analyzed using IBM SPSS Statistics v.21 (IBM Corp., Armonk, NY). The Kolmogorov-Smirnov test, independent samples t-test, Mann-Whitney U test, and Pearson's and Spearman's rho correlation coefficient were used. A p-value <0.05 was considered statistically significant. Results There was a statistically significant relationship between beta-thalassemia patients who had cardiac iron deposition and those who did not in terms of T2* time (p=0.02). In contrast, there was no similar relationship for liver iron deposition (p>0.05). Renal T2* values were significantly different between the patient and control groups (p=0.029). T2* times were significantly different between patients who had ferritin levels below 2500 ng/ml and those with ferritin levels above 2500 ng/ml (p=0.042). Conclusion Based on our findings, 3T MRI is a safe and reliable tool for screening iron overload in BTM patients as it makes distinguishing between renal parenchyma and renal sinus much easier and as it is more sensitive to iron deposition.

The Assessment of Renal Functional Reserve in β-Thalassemia Major Patients by an Innovative Ultrasound and Doppler Technique: A Pilot Study

Beta-thalassemia syndromes are the most common inherited monogenic disorders worldwide. The most common pathophysiologic and clinical renal disease manifestations of in β-TM patients is the tubular dysfunctions related to iron overload, chronic anemia, and the need for chronic iron chelation therapy. The aim of this pilot study is to apply an innovative ultrasound and Doppler technique to assess the Renal Functional Reserve (RFR) in β-TM patients, and to evaluate its reliability in iron overload tubulopathy. Ultrasound assessment of intra-parenchymal renal resistive index variation (IRRIV) has recently been proposed as a safe and reproducible technique to identify RFR presence. We define the preserved RFR when the Delta Renal Resistive Index (RRI) is >0.05 (baseline RRI—minimum RRI value during stress) in the Renal Stress Test (RST). Nineteen β-TM patients were enrolled for this study. In our series, we found a strong negative correlation between mean ferritin values and Delta RRI (R = −0.51, p = 0.03). This pilot study suggested the RST as reliable tool for assessing the RFR by ultrasound. Specifically, RST could help in clinical practice suggesting the patient’s management and iron chelation therapy.

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

BACKGROUND

Renal injury in transfusion dependent β 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.

Comparative evaluation of cystatin C and neutrophil gelatinase-associated lipocalin in patients with thalassemia major versus thalassemia intermedia

Kidney disorders are long-term complications in thalassemia patients, especially with the high life expectancy of these patients. Proper evaluation of kidney impairment in β-thalassemia patients can be difficult due to higher intake of iron chelators, resulting in renal impairment. Early biomarkers of renal disease are used for the diagnosis of tubular and glomerular abnormalities. The current study was conducted on 88 individuals, 25 healthy people and 63 β-thalassemia patients. Circulating levels of urea, creatinine, cystatin C and neutrophil gelatinase-associated lipocalin were measured in all groups. Compared to healthy control, patients with thalassemia major and intermedia showed a significant increase in both cystatin C and NGAL levels, with no effects on creatinine levels. Furthermore, urea levels were markedly higher in patients with thalassemia major compared to control. As early renal dysfunction markers, cystatin C and NGAL should be routinely evaluated in thalassemia patients major and intermedia.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Comparing different markers of tubular dysfunction in transfusion-dependent thalassemia patients

BACKGROUND

Renal tubular dysfunction was reported in transfusion-dependent thalassemia (TDT) patients and ranges from mild to severe. The objectives of our study were identification of the best marker of early renal tubular dysfunction in TDT patients among the three most commonly used urinary biomarkers, named neutrophil gelatinase-associated lipocalin (NGAL), retinol-binding protein (RBP) and N-acetyl-D-glucosaminidase (NAG) and correlation of these biomarkers with different patient variables.

METHODOLOGY

Sixty-one TDT patients and another 62 healthy children were enrolled in a cross-sectional study. Morning urine samples were taken for measurement of calcium, phosphorus, creatinine, microalbumin and markers of tubular dysfunction (NGAL, NAG and RBP). Urine NGAL/creatinine (UrNGAL/Cr), urine NAG/creatinine (UrNAG/Cr) and urine RBP/creatinine (UrRBP/Cr) ratios were used for accuracy. Patients were classified into 2 groups: group A, with tubular dysfunction and group b, without tubular dysfunction.

RESULTS

Group A showed statistically significant higher UrNGAL/Cr (p < 0.001), UrRBP/Cr (p < 0.001) and UrNAG/Cr (p <0.001) than group B. In group A, microalbuminuria was detected only in 7 patients (28%) while it was detected in 12 patients (33.3%) in group B. By using ROC curve analysis, the diagnostic cutoff values for UrNGAL/Cr, UrRBP/Cr and UrNAG/Cr were 3713.38, 1614.85 and 56.56 ng/g, respectively. We found a statistically significant superiority of UrNGAL/Cr over UrRBP/Cr (p < 0.001) and UrRBP/Cr over UrNAG/Cr (p < 0.001).

CONCLUSION

Evaluation of UrNGAL/Cr, UrRBP/Cr and UrNAG/Cr could early discriminate tubular dysfunction TDT patients from those with normal tubular function. UrNGAL/Cr is more accurate in early detection of tubular dysfunction when compared with the other two biomarkers.

Netrin-1 and clusterin: Innovative potential diagnostic biomarkers for early renal damage in β-thalassemia major children

BACKGROUND

Children with β-thalassemia major (β-TM) suffer from tubular dysfunction even before the onset of any renal impairment symptoms and/or clinical signs. Therefore, identifying innovative biomarkers allowing early renal damage detection has focused attention.

AIM

This study aims to preliminary assess Netrin-1(NTN-1) and clusterin (CLU) in β-TM children and explore their possible roles as surrogate noninvasive biomarkers of renal tubular dysfunction.

SUBJECTS AND METHODS

In this study, 40 β-TM children and 30 healthy children were enrolled. Routine serum and urinary biochemical variables were determined. Urinary NTN-1 and CLU levels were measured using ELISA and their mRNA expression in PBMCs were assayed using real-time PCR. Serum TNF-α, MDA levels and GST activity were measured.

RESULTS

Urinary NTN-1 and CLU concentrations and mRNA relative expression levels in PBMCs were significantly increased in β-TM children relative to controls. Oxidative stress and inflammatory markers revealed significant elevation in β-TM children compared to controls. The change in these parameters correlated significantly with other renal parameters. ROC curves analysis showed that urinary NTN-1 and CLU levels are of promising diagnostic performance.

CONCLUSION

Our results suggest that NTN-1 and CLU are qualified as new noninvasive biomarker panels for early detection of renal injury in β-TM children. Moreover, urinary NTN-1 is recommended as a precise one during the clinical practices.

Assessment of Subclinical Renal Glomerular and Tubular Dysfunction in Children with Beta Thalassemia Major

Background: A good survival rate among patients with beta thalassemia major (beta-TM) has led to the appearance of an unrecognized renal disease. Therefore, we aimed to assess the role of serum cystatin-C as a promising marker for the detection of renal glomerular dysfunction and N-acetyl beta-D-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1) as potential markers for the detection of renal tubular injury in beta-TM children. Methods: This case-control study was implemented on 100 beta-TM children receiving regular blood transfusions and undergoing iron chelation therapy and 100 healthy children as a control group. Detailed histories of complete physical and clinical examinations were recorded. All subjected children underwent blood and urinary investigations. Results: There was a significant increase in serum cystatin-C (p < 0.001) and a significant decrease in eGFR in patients with beta-TM compared with controls (p = 0.01). There was a significant increase in urinary NAG, KIM-1, UNAG/Cr, and UKIM-1/Cr (p < 0.001) among thalassemic children, with a significant positive correlation between serum cystatin-C, NAG and KIM-1 as regards serum ferritin, creatinine, and urea among thalassemic patients. A negative correlation between serum cystatin-C and urinary markers with eGFR was noted. Conclusion: Serum cystatin-C is a good marker for detection of glomerular dysfunction. NAG and KIM-1 may have a predictive role in the detection of kidney injury in beta-TM children.

Consumption of a green tea extract-curcumin drink decreases blood urea nitrogen and redox iron in β-thalassemia patients

The most important cause of death in β-thalassemia major patients is organ dysfunction due to iron deposits. Non-transferrin bound iron (NTBI), labile plasma iron (LPI) and labile iron pool are redox-active forms of iron found in thalassemia. Iron chelation therapy is adopted to counteract the resulting iron overload. Extracts of green tea (GTE) and curcumin exhibit iron-chelating and antioxidant activities in iron-loaded cells and β-thalassemic mice. We have used our GTE-CUR drink to investigate the potential amelioration of iron overload and oxidative stress in transfusion-dependent β-thalassemia (TDT) patients. The patients were enrolled for a control group without and with GTE-CUR treatments (17.3 and 35.5 mg EGCG equivalent). Along with regular chelation therapy, they were daily administered the drink for 60 d. Blood samples were collected at the beginning of the study and after 30 d and 60 d for biochemical and hematological tests. Interestingly, we found a decrease of blood urea nitrogen levels (P < 0.05), along with a tendency for a decrease of NTBI and LPI, and a delay in increasing lipid-peroxidation product levels in the GTE-CUR groups. The findings suggest that GTE-CUR could increase kidney function and diminish redox-active iron in iron overloaded β-thalassemia patients.

Hyperferritinemia and acute kidney injury in pediatric patients receiving allogeneic hematopoietic cell transplantation

BACKGROUND

Acute kidney injury (AKI) often occurs in pediatric patients who received allogeneic hematopoietic cell transplantation (HCT). We evaluated the risk and effect of HCT-related AKI in pediatric patients.

METHODS

We retrospectively studied the survival and renal outcome of 69 children 100 days and 1-year posttransplant in our institution in 2004-2016. Stage-3 AKI developed in 34 patients (49%) until 100 days posttransplant.

RESULTS

The 100-day overall survival (OS) rates of patients with stage-3 AKI were lower than those without it (76.5% vs. 94.3%, P = 0.035). The 1-year OS rates did not differ markedly between 21 post-100-day survivors with stage-3 AKI and 29 without it (80.8% vs. 87.9%, P = 0.444). The causes of 19 deaths included the relapse of underlying disease or graft failure (n = 11), treatment-related events (4), and second HCT-related events (4). Underlying disease of malignancy (crude hazard ratio (HR) 5.7; 95% confidence interval (CI), 2.20 to 14.96), > 1000 ng/mL ferritinemia (crude HR 4.29; 95% CI, 2.11 to 8.71), stem cell source of peripheral (crude HR 2.96; 95% CI, 1.22 to 7.20) or cord blood (crude HR 2.29; 95% CI, 1.03 to 5.06), and myeloablative regimen (crude HR 2.56; 95% CI, 1.24 to 5.26), were identified as risk factors for stage-3 AKI until 100 days posttransplant. Hyperferritinemia alone was significant (adjusted HR 5.52; 95% CI, 2.21 to 13.76) on multivariable analyses.

CONCLUSIONS

Hyperferritinemia was associated with stage-3 AKI and early mortality posttransplant. Pretransplant iron control may protect the kidney of pediatric HCT survivors.

Recent Progress in Gene Therapy and Other Targeted Therapeutic Approaches for Beta Thalassemia

Beta-thalassemia is a genetic disorder characterized by the impaired synthesis of the betaglobin chain of adult hemoglobin. The disorder has a complex pathophysiology that affects multiple organ systems. The main complications of beta thalassemia are ineffective erythropoiesis, chronic hemolytic anemia and hemosiderosis-induced organ dysfunction. Regular blood transfusions are the main therapy for beta thalassemia major; however, this treatment can cause cardiac and hepatic hemosiderosis - the most common cause of death in these patients. This review focuses on unique future therapeutic interventions for thalassemia that reverse splenomegaly, reduce transfusion frequency, decrease iron toxicity in organs, and correct chronic anemia. The targeted effective protocols include hemoglobin fetal inducers, ineffective erythropoiesis correctors, antioxidants, vitamins, and natural products. Resveratrol is a new herbal therapeutic approach which serves as fetal Hb inducer in beta thalassemia. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for beta thalassemia major and is preferred over iron chelation and blood transfusion for ensuring long life in these patients. Meanwhile, several molecular therapies, such as ActRIIB/IgG1 Fc recombinant protein, have emerged to address complications of beta thalassemia or the adverse effects of current drugs. Regarding gene correction strategies, a phase III trial called HGB-207 (Northstar-2; NCT02906202) is evaluating the efficacy and safety of autologous cell transplantation with LentiGlobin. Advanced gene-editing approaches aim to cut DNA at a targeted site and convert HbF to HbA during infancy, such as the suppression of BCL11A (B cell lymphoma 11A), HPFH (hereditary persistence of fetal hemoglobin) and zinc-finger nucleases. Gene therapy is progressing rapidly, with multiple clinical trials being conducted in many countries and the promise of commercial products to be available in the near future.

β2-Microglobulin, Neutrophil Gelatinase-Associated Lipocalin, and Endocan Values in Evaluating Renal Functions in Patients with β-Thalassemia Major

Chronic anemia, transfusion-associated iron deposition, and chelating agents lead to renal impairment in β-thalassemia (β-thal) patients. The present study aimed to determine the most reliable and practical method in assessing and predicting renal injury in β-thal major (β-TM) patients. Therefore, we assessed the predictive values of urine β2-microglobulin (β2-MG) and neutrophil gelatinase-associated lipocalin (NGAL) levels, their ratios to urine creatinine, and serum endocan level. Sixty β-TM patients and 30 healthy controls were included. Renal functions of the patients and controls were evaluated by means of urine protein/creatinine ratio, urine β2-MG, urine NGAL, and serum endocan level. The β-TM and control groups were comparable in terms of the demographic characteristics. Of the β-TM patients, 26.7% had glomerular hyperfiltration and 41.7% had proteinuria. Compared with the control group, the β-TM group had significantly higher levels of urine protein/creatinine, urine β2-MG, urine β2-MG/creatinine, urine NGAL, urine NGAL/creatinine, and serum endocan. These parameters did not differ between the chelating agent subgroups in the patient group. Urine β2-MG/creatinine and NGAL/creatinine ratios were the parameters with high specificity in predicting proteinuria. There were significant correlations of urine β2-MG, urine NGAL, and serum endocan levels with serum ferritin concentration. Urine β2-MG/creatinine, NGAL/creatinine, and protein/creatinine ratios were correlated with each other in the patient group. Positive correlations of urine β2-MG, urine NGAL, and serum endocan levels with serum ferritin concentration indicated that iron deposition was associated with endothelial damage and renal injury.

Deferasirox in thalassemia: a comparative study between an innovator drug and its copy among a sample of Iraqi patients

Background:

The health care industry is witnessing an increasing trend in the use of generic medicines because of their presumed low cost compared with innovator medicines. The aim of this study was to determine and compare the performance of the copy drug Osveral^® and its innovator drug deferasirox (Exjade^®).

Methods:

A prospective observational study including 223 patients receiving the branded medicine Exjade^® and 101 patients receiving the copy Osveral^® was carried out. Data were assessed for a 1-year period and included clinical symptoms, serum ferritin (SF), serum creatinine (SC), and alanine aminotransferase (ALT). Data were analyzed with SPSS version 22 software (SPSS, Chicago, IL, USA).

Results:

The median age of the sample was 8 years. There was no significant difference in gender distribution between the two groups (p = 0.625). Nausea was the most frequently reported adverse effect followed by diarrhea and abdominal pain in both groups. Patients receiving Exjade^® had a higher relative reduction of SF at the end of the study compared with the Osveral^® group (19.9% versus 9.93%, p = 0.028). SC was found to be significantly higher in the Osveral^® group than in the Exjade^® group throughout the study period. The mean platelet count was higher in the Exjade^® group. ALT was significantly higher among patients receiving Osveral^® over the last three months of the study.

Conclusions:

Exjade^® showed a better ability to reduce SF, with less liver toxicity, and better hemostasis profile. No congenital anomalies associated with short-term use of both drugs during pregnancy were observed or reported.

Evaluation of Renal Function Disorder With Urinary Neutrophil Gelatinase-associated Lipocalin Level in Patients With β-Thalassemia Major

BACKGROUND AND AIM

Neutrophil gelatinase-associated lipocalin (NGAL) is found in the granules of human neutrophils, with many diverse functions. Expression of NGAL is induced under various pathophysiological conditions, for example, infection, inflammation, kidney injury, cardiovascular disease, burn injury, and intoxication, and it has an important antiapoptotic and anti-inflammatory role.

PATIENTS AND METHODS

A total of 37 patients with thalassemia disease β-thalassemia major (24 male and 13 female individuals) and 37 healthy controls (17 male and 20 female) were enrolled in this study. All patients were regularly transfused, and all of them were using oral chelator, deferasirox.

RESULTS

NGAL and cystatin C levels were significantly higher in the case group than in the control group.

CONCLUSION

In patients with β-thalassemia major, renal damage can occur owing to regular blood transfusion. Urinary NGAL levels in these patients may be considered as a marker for early renal injury.

Subclinical nephrotoxicity in patients with beta-thalassemia: role of urinary kidney injury molecule

We aimed to investigate the role of urinary kidney injury molecule-1 (KIM-1) in detection of subclinical nephrotoxicity in patients with Beta-thalassemia (β-TM) in relation to chelation therapy and to correlate the urinary KIM-1 level with other clinical and laboratory findings. We conducted a cross-sectional study on 66 thalassemic patients. Their ages range from 7 to 22 years. Routine kidney indices and novel urinary KIM/creatinine ratio (U_KIM-1/Cr) were measured. Estimated glomerular filtration rate (eGFR) was calculated. Results indicate that the level of serum creatinine was significantly higher in patients on deferasirox therapy than patients on deferoxamine and deferiprone therapy [median(IQR), 0.85(0.63-0.99), 0.50(0.34-0.58) and 0.44(0.36-0.45)] mg/dL, respectively, p < 0.001]. The median(IQR) level of eGFR was significantly lower in patients on deferasirox therapy than patients on deferoxamine and deferiprone therapy [63.3(56.5-92.1), 117.3(91.9-162) and 136.7(109.4-157.6)] ml/min/1.73 m², respectively, p < 0.001]. The mean level of U_KIM-1/Cr was significantly higher in patients on deferasirox therapy than patients on deferoxamine and deferiprone therapy (7.0 ± 1.9, 4.1 ± 1.7 and 4.2 ± 1.5) ng/mg creatinine, respectively, p < 0.001). We concluded that urinary KIM-1 is an early predictive biomarker for decline in eGFR in patients with β-TM on deferasirox therapy. The appropriate chelation therapy and good monitoring of those patients are intensely needed for early detection of renal dysfunction and timely intervention.

Beta-thalassemia: renal complications and mechanisms: a narrative review

OBJECTIVES

Beta-thalassemias are a group of recessively autosomal inherited disorders of hemoglobin synthesis, which, due to mutations of the beta-globin gene, lead to various degrees of defective beta-chain production, an imbalance in alpha/beta-globin chain synthesis, ineffective erythropoiesis, and anemia. Improved survival in thalassemic patients has led to the emergence of previously unrecognized complications, such as renal disease.

METHODS

A comprehensive literature review through PubMed was undertaken to summarize the published evidence on the epidemiology and pathophysiology of renal disease in thalassemia. Literature sources published in English since 1990 were searched, using the terms beta-thalassemia, renal disease.

RESULTS

Renal disease is considered to be the 4th cause of morbidity among patients with transfusion dependent thalassemia. Chronic anemia, hypoxia and iron overload are the main mechanisms implicated in development of renal injury, whereas several studies also suggested a contributive role of iron chelators.

DISCUSSION AND CONCLUSION

Kidney disease may develop through progressive renal tubular and glomerular damage; thus, its early recognition is important in order to prevent and/or reverse deterioration. This review will provide an insight on the involved mechanisms implicated in kidney disease in thalassemic patients and will discuss the updates on diagnosis and prevention of renal complications in thalassemia.

Iron uptake by ZIP8 and ZIP14 in human proximal tubular epithelial cells

In patients with iron overload disorders, increasing number of reports of renal dysfunction and renal iron deposition support an association between increased iron exposure and renal injury. In systemic iron overload, elevated circulating levels of transferrin-bound (TBI) and non-transferrin-bound iron (NTBI) are filtered to the renal proximal tubules, where they may cause injury. However, the mechanisms of tubular iron handling remain elusive. To unravel molecular renal proximal tubular NTBI and TBI handling, human conditionally immortalized proximal tubular epithelial cells (ciPTECs) were incubated with ⁵⁵Fe as NTBI and fluorescently labeled holo-transferrin as TBI. Ferrous iron importers ZIP8 and ZIP14 were localized in the ciPTEC plasma membrane. Whereas silencing of either ZIP8 or ZIP14 alone did not affect ⁵⁵Fe uptake, combined silencing significantly reduced ⁵⁵Fe uptake compared to control (p < 0.05). Furthermore, transferrin receptor 1 (TfR1) and ZIP14, but not ZIP8, colocalized with early endosome antigen 1 (EEA1). TfR1 and ZIP14 also colocalized with uptake of fluorescently labeled transferrin. Furthermore, ZIP14 silencing decreased ⁵⁵Fe uptake after ⁵⁵Fe-Transferrin exposure (p < 0.05), suggesting ZIP14 could be involved in early endosomal transport of TBI-derived iron into the cytosol. Our data suggest that human proximal tubular epithelial cells take up TBI and NTBI, where ZIP8 and ZIP14 are both involved in NTBI uptake, but ZIP14, not ZIP8, mediates TBI-derived iron uptake. This knowledge provides more insights in the mechanisms of renal iron handling and suggests that ZIP8 and ZIP14 could be potential targets for limiting renal iron reabsorption and enhancing urinary iron excretion in systemic iron overload disorders.

International sentinel site surveillance of patients with transfusional hemosiderosis treated with deferasirox in actual practice setting

OBJECTIVE

The study evaluates the long-term deferasirox treatment of adult and pediatric patients with chronic transfusional iron overload in clinical practice.

METHODS

In this non-interventional study, patients were observed for up to 3 years from initiation of deferasirox treatment both prospectively and retrospectively for up to 1 year prior to enrollment. The primary end points were the proportion of patients with ≥1 notable increase in serum creatinine (SCr), and ≥1 notable increase in alanine aminotransferase (ALT).

RESULTS

Overall, 120 patients were enrolled and 51 completed the study, with a limited 3-year dropout rate of 12.5% due to adverse events (AEs). Increase in SCr > 33% above baseline and the age-adjusted ULN (upper limit of normal) was observed in 14 patients (95%CI, 7.1-19.2). The ALT levels >5 × ULN was observed in 1 patient. Most frequent AEs reported during treatment with deferasirox include gastrointestinal disturbances.

CONCLUSIONS

The long-term treatment with deferasirox was manageable in most transfusion-dependent patients with no unexpected safety findings. Regular monitoring and an adjusted deferasirox dosing strategy per local labels allowed continued iron chelation treatment and control of transfusional iron in the majority of patients on study.

Under-recognized Hypoparathyroidism in Thalassemia

OBJECTIVE

Symptomatic hypoparathyroidism [symptomatic hypocalcemia without elevated serum parathyroid hormone (PTH)] in patients with thalassemia is relatively rare. Asymptomatic mild hypocalcemia without elevated PTH, which is considered hypoparathyroidism, may be more common but under-recognized.

METHODS

Sixty-six transfusion-dependent thalassemic patients and 28 healthy controls were enrolled. Serum calcium (Ca), phosphate (P), creatinine (Cr), albumin, intact PTH, 25-hydroxyvitamin D (25-OHD), plasma intact fibroblast growth factor-23 (FGF-23), urinary Ca, P and Cr were measured. Tubular reabsorption of P was calculated.

RESULTS

Thalassemic patients had significantly lower median serum Ca levels than the controls [8.7 (7.8-9.7) vs 9.6 (8.7-10.1) mg/dL, p<0.001]. Hypoparathyroidism was found in 25 of 66 (38%) patients. Symptomatic hypoparathyroidism was not encountered. Thalassemic patients also had significantly lower median plasma FGF-23 levels than the controls [35.7 (2.1-242.8) vs 53.2 (13.3-218.6) pg/mL, p=0.01]. In patients with hypoparathyroidism, median plasma FGF-23 level was significantly lower than that of normoparathyroid patients [34.8 (2.1-120.0) vs 43.1 (3.2-242.8) pg/mL, p=0.048]. However, serum P, Cr, intact PTH and 25-OHD levels were not significantly different in the two groups.

CONCLUSION

Hypoparathyroidism was not uncommon in patients with transfusion-dependent thalassemia treated with suboptimal iron chelation. Plasma intact FGF-23 level in hypoparathyroid patients was lower than that of normoparathyroid patients.

Renal complications in thalassemia

Thalassemia is a disease with an extensive morbidity profile affecting almost every organ system. Renal involvement, once considered rare, is an underestimated and poorly studied complication that has been on the rise ever since medical advances granted patients longer life spans. Several studies and reports have emerged recently to shed light on the seriousness of this complication, although data is still lacking in terms of pathophysiology, diagnosis, prevention and treatment. In this review, we evaluate and compare renal involvement in the transfusion-dependent and independent variants of β-Thalassemia, highlighting the pathophysiology of kidney damage that involves iron overload, chronic anemia, and iron chelation therapy. An in-depth and focused review of the types of injuries incurred is also presented along with the diagnostic biomarkers accompanying each type of injury. Most research so far has focused on the transfusion-dependent thalassemia population being the group with most renal involvement, however recent reports have shown evidence of comparable, if not worse, involvement of the non-transfusion dependent population, sometimes leading to end-stage renal disease. As such, we try to shed light on distinct renal involvements in NTDT whenever available.

Long-term safety and efficacy of deferasirox in young pediatric patients with transfusional hemosiderosis: Results from a 5-year observational study (ENTRUST)

BACKGROUND

Children with red blood cell disorders may receive regular transfusions from an early age and consequently accumulate iron. Adequate iron chelation therapy can prevent organ damage and delayed growth/development. Deferasirox is indicated for treatment of pediatric patients with chronic iron overload due to transfusional hemosiderosis; however, fewer than 10% of patients in the registration studies were aged 2 to less than 6 years.

PROCEDURE

Deferasirox, a once-daily oral iron chelator, was evaluated in young pediatric patients with transfusional hemosiderosis during the observational 5-year ENTRUST study. Patients aged 2 to less than 6 years at enrollment received deferasirox according to local prescribing information, with the primary objective of evaluating safety, specifically renal and hepatic function. Serum ferritin was observed as a surrogate efficacy parameter.

RESULTS

In total, 267 patients (mean age 3.2 years) predominantly with β-thalassemia (n = 176, 65.9%) were enrolled. Mean ± standard deviation deferasirox dose was 25.8 ± 6.5 mg/kg per day over a median of 59.9 months. A total of 145 patients (54.3%) completed 5 years' treatment. The proportion of patients with two or more consecutive postbaseline measurements (≥7 days apart) of serum creatinine higher than age-adjusted upper limit of normal (ULN) and alanine aminotransferase more than five times the ULN was 4.4% (95% confidence interval [CI]: 2.1-7.9) and 4.0% (95% CI: 1.8-7.4), respectively. Median serum ferritin decreased from 1,702 ng/ml at baseline to 1,127 ng/ml at 5 years. There were no new safety signals.

CONCLUSIONS

Safety and efficacy of deferasirox in young pediatric patients in this long-term, observational study in everyday clinical practice were consistent with the known deferasirox profile.

Glomerular and Tubular Functions in Children and Adults with Transfusion-Dependent Thalassemia

This study aimed at assessing renal functions in patients with transfusion-dependent thalassemia (TDT). Fifty patients and 30 controls were enrolled in this prospective study. Serum levels of electrolytes and albumin were measured by a spectrophotometer. Serum levels of cystatin-C and urinary levels of β2-microglobulin were measured by nephelometric method. Thirty-eight patients were receiving deferasirox and 8 were on deferiprone. Serum electrolytes and albumin levels of the patients were found to be within normal ranges. Urinary β2-microglobulin and serum cystatin-C levels were significantly higher in patients than controls. They did not significantly differ between the subgroup of patients on deferiprone and the control group, whereas they were found to be higher in patients using deferasirox compared to controls. Urinary β2-microglobulin levels significantly increased in patients who were receiving high-dose deferasirox compared to those who were receiving a daily dose of 15-20 mg/kg or controls. Subclinical renal injury may be present in TDT patients.

Glomerular and tubular functions in children with different forms of beta thalassemia

BACKGROUND

Although there are many available data about renal involvement in patients with beta thalassemia major (TM), the changes in renal functions of other types, such as thalassemia intermedia (TI) and thalassemia minor (TMin), were reported less. Therefore, we aimed to evaluate renal tubular and glomerular functions in patients with three types of beta thalassemia.

METHODS

This prospective case-control study was conducted on 118 beta-thalassemia patients (49 in TM, 18 in TI and 51 TMin) and 51 healthy controls. Glomerular functions [estimated glomerular filtration rate (GFR), serum cystatin C and urinary protein creatinine ratio] and tubular functions [fractioned sodium excretion (FENa), tubular reabsorption of phosphorus, urinary excretion of uric acid, levels of retinol-binding protein, alpha-1 macroglobulin (alpha-1M), and beta-2 microglobulin, calcium creatinine ratio] were assessed in all patients and controls.

RESULTS

The mean ages of the groups and controls at presentation were similar. Although GFR was similar in all patients and control groups, serum levels of cystatin C in patients with TM and TI were significantly higher compared to TMin and controls. Alpha-1M, FENa, urinary excretion of uric acid, and urine protein/creatinine ratio in TM and TI groups were significantly higher than the others. Mean cystatin C level was also higher in patients with TMin compared the controls. However, there were no significant differences according to all tubular and other glomerular functions between TMin and control groups.

CONCLUSIONS

Although all types of beta thalassemia patients should be closely monitored to prevent further decrease in renal functions, the patients with TI should be considered to have a higher risk of glomerular and tubular deterioration as well as TM.

GFR in Patients with β-Thalassemia Major

BACKGROUND AND OBJECTIVES

Patients with β-thalassemia major (TM) may have tubular dysfunction and glomerular dysfunction, primarily hyperfiltration, based on eGFR. Assessment of GFR based on serum creatinine concentration may overestimate GFR in these patients. This study sought to determine GFR by using inulin clearance and compare it with measured creatinine clearance (Ccr) and eGFR.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Patients followed up in an Israeli thalassemia clinic who had been regularly transfused for years and treated with deferasirox were included in the study. They were studied by inulin clearance, Ccr, the CKD Epidemiology Collaboration and the Modification of Diet in Renal Disease equations for eGFR, and the Cockcroft-Gault estimation for Ccr. Expected creatinine excretion rate and tubular creatinine secretion rate were calculated.

RESULTS

Nine white patients were studied. Results, given as medians, were as follows: serum creatinine was 0.59 mg/dl (below normal limits); GFR was low (76.6 ml/min per 1.73 m(2)) and reached the level of CKD; Ccr was 134.9 ml/min per 1.73 m(2), higher than the GFR because of a tubular creatinine secretion rate of 30.3 ml/min per 1.73 m(2) (this accounted for 40% of the Ccr); and eGFR calculated by the CKD Epidemiology Collaboration and Modification of Diet in Renal Disease equations and Cockcroft-Gault-estimated Ccr were 133, 141, and 168 ml/min per 1.73 m(2), respectively. These latter values were significantly higher than the GFR, reaching the hyperfiltration range, and indicated that the estimation techniques were clinically unacceptable as a method for measuring kidney function compared with the GFR according to Bland and Altman analyses.

CONCLUSIONS

Contrary to previous reports, patients in this study with TM had normal or reduced GFR. The estimating methods showed erroneous overestimation of GFR and were clinically unacceptable for GFR measurements in patients with TM by Bland and Altman analysis. Therefore, more accurate methods should be used for early detection of reduced GFR and prevention of its further decline toward CKD in these patients.

Urinary early kidney injury molecules in children with beta-thalassemia major

BACKGROUND

The aim of this study was to investigate novel urinary biomarkers including N-acetyl-β-D-glucosaminidase (NAG), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and liver-type fatty acid binding protein (L-FABP) in children with β-thalassemia major (β-TM).

MATERIALS AND METHODS

Totally, 52 patients (29 boys, 23 girls) with β-TM and 29 healthy controls (3-17 years) were included. Various demographic characteristics and blood transfusions/year, disease duration, and chelation therapy were recorded. Serum urea, creatinine, electrolytes, and ferritin and urinary creatinine, protein, calcium, phosphorus, sodium, potassium, and uric acid in first morning urine samples were measured and estimated glomerular filtration rate (eGFR) was calculated. Routine serum and urinary biochemical variables, urinary NAG to Creatinine (U(NAG/Cr)), U(NGAL/Cr), U(KIM-1/Cr), and U(L-FABP/Cr) ratios were determined.

RESULTS

Patients had similar mean serum urea, creatinine and eGFR levels compared with controls (p > 0.05 for all). The mean urinary protein to creatinine (U(Protein/Cr)) ratio was significantly higher in patients compared to the healthy subjects (0.13 ± 0.09 mg/mg and 0.07 ± 0.04 mg/mg, respectively; p < 0.001). Significantly increased U(NAG/Cr) (0.48 ± 0.58 vs. 0.23 ± 0.16, p = 0.026) and U(NGAL/Cr) (22.1 ± 18.5 vs. 11.5 ± 6.17, p = 0.01) ratios were found in β-TM patients compared with healthy controls. However, no differences were found in serum and urinary electrolytes or U(KIM-1/Cr) and U(L-FABP/Cr) ratios between patients and controls (p > 0.05). Significant correlations were found between urinary biomarkers and urinary electrolytes (p < 0.05).

CONCLUSIONS

Our results suggest that urinary NAG and NGAL may be considered to be reliable markers to monitor renal injury in β-TM patients.

Early Predictors of Renal Dysfunction in Egyptian Patients with β-Thalassemia Major and Intermedia

Background

Better survival of thalassemia patients allowed previously unrecognized renal complications to emerge.

Objectives

Assess prevalence and early predictors of renal dysfunction in young β-thalassemia major (β-TM) and intermedia (β-TI) patients.

Subjects

66 β-TM (group I), 26 β-TI (group II) Egyptian patients and 40 healthy controls.

Methods

Clinical assessment and laboratory data including kidney and liver function tests, such as serum ferritin, serum bicarbonate, plasma osmolality and urinary total proteins, microalbuminuria (MAU), N-acetyl-β-D-glucosaminidase (NAG), retinol binding protein (RBP), α-1 microglobulin, bicarbonate, osmolality, creatinine clearance (CrCl), % fractional excretion of bicarbonate (% FE-HCO3).

Results

The prevalent renal abnormality was proteinuria (71%), followed by increased urinary level of RBP (69.4%), NAG (58.1%), α-1 microglobulin (54.8%) and microalbuminuria (29%) and also decreased urinary osmolality (58.1%). CrCl was a better assessment of renal function and significantly lowered in thalassemia patients. Tubular dysfunctions were more significant in splenectomized β-TM patients who showed more elevation of NAG and α-1 microglobulin and lower urinary osmolality. NAG, RBP and α-1 microglobulin were negatively correlated with CrCl and positively correlated with serum ferritin and urinary total protein. Z-score analysis for identifying patients with renal dysfunction proved superiority of urine total protein and RBP. Comparative statistics of different frequencies revealed significant difference between the urinary total protein and both MAU and % FE-HCO3.

Conclusion

Asymptomatic renal dysfunctions are prevalent in young β-TM and β-TI patients that necessitate regular screening. Urinary total protein and RBP may be cost-effective for early detection.

Renal function in transfusion-dependent pediatric beta-thalassemia major patients

PURPOSE

In this study, the relationship between glomerular and tubular function and creatinine, glomerular filtration rate (GFR) and urine NAG in thalassemia major patients aged 7-16 years was investigated.

DESIGN AND SETTING

This is a case-control study comprising 280 individuals [144 (51·4%), males; 136 (48·6%), females].

MATERIALS AND METHODS

Patients were divided in groups of 14 individuals and age groups of 7-16 years. Sodium excretion fraction, fraction excretion of potassium, calcium-to-creatinine and uric acid-to-creatinine ratios, and duration of specific blood transfusion were determined in all age groups receiving deferoxamine.

RESULTS

GFR decreased with increasing age, but the correlation was not statistically significant. There was no significant correlation between the ferritin levels and the GFR changes. The mean value of NAG activity between thalassemic patients and controls has no significant difference. The difference in mean age of the groups with high NAG activity and normal NAG activity was statistically significant. Thirty-seven patients (52·1%) in the group with normal NAG activity, and 45 patients (6·25%) in the group with NAG activity above normal were observed with uricosuric effects with no significant difference. Four patients (6·9%) in the group with normal NAG activity and six patients (7·3%) in the group with NAG activity above normal were shown to have hematuria with no significant difference. The results show that the increase in serum ferritin is significantly correlated with the increase in NAG activity (P<0·001, r = 0·2). Of patients with normal NAG activity 1 (1·7%) and with NAG activity higher than normal, 13 (15·9%) cases experienced hypercalciuria that significant difference was existing. The data also indicated that the NAG changes do not correlate with GFR changes.

CONCLUSION

The results showed that kidney dysfunction in thalassemia increases with increasing age, duration, and levels of blood transfusion and hypercalciuria. It is therefore recommended that the presence of severe renal dysfunction in thalassemic patients should be investigated using sensitive and specific tests, mainly NAG, to prevent progress towards the complications.

A prospective study of tubular dysfunction in pediatric patients with Beta thalassemia major receiving deferasirox

BACKGROUND

Beta thalassemia major is a lifelong transfusion-dependent disorder. Transfusion-dependent thalassemia patients are prone to develop renal dysfunction due to iron overload, chronic anemia, and/or chelation therapy.

METHODS

In this prospective study, thalassemia patients who fitted inclusion and exclusion criteria received Deferasirox 20 mg/kg/day. A complete biochemistry analysis of serum and 24-hour-urine specimens was performed before and after treatment. Estimated glomerular filtration rate (eGFR), Fractional excretion of sodium (FENA), potassium (FEK), uric acid (FEUA), and the maximum ratio of tubular reabsorption of phosphorus to eGFR (TmP/GFR) at baseline and after treatment was calculated and compared.

RESULTS

A total of 30 patients with mean age of 4.9 ± 3.2 years were recruited. The mean serum creatinine increased significantly after 6 months of treatment (0.54 ± 0.08 vs. 0.67 ± 0.16, P < .001) while eGFR was decreased (104.36 ± 19.62 vs. 86.00 ± 16.92, P < .001). Mean potassium level in serum was increased after treatment, while serum calcium, magnesium, and uric acid levels decreased significantly (P > .05). A significant increase was confirmed for mean urinary β2-microglobulin (β2-MG), protein, uric acid, calcium, and magnesium (P > .05).

CONCLUSION

Our findings highlighted tubular nephropathy induced by Deferasirox in patients with beta thalassemia, and confirmed the necessity for diligent monitoring of renal function in thalassemia patients receiving Deferasirox.

Cardiovascular function and treatment in β-thalassemia major: a consensus statement from the American Heart Association

This aim of this statement is to report an expert consensus on the diagnosis and treatment of cardiac dysfunction in β-thalassemia major (TM). This consensus statement does not cover other hemoglobinopathies, including thalassemia intermedia and sickle cell anemia, in which a different spectrum of cardiovascular complications is typical. There are considerable uncertainties in this field, with a few randomized controlled trials relating to treatment of chronic myocardial siderosis but none relating to treatment of acute heart failure. The principles of diagnosis and treatment of cardiac iron loading in TM are directly relevant to other iron-overload conditions, including in particular Diamond-Blackfan anemia, sideroblastic anemia, and hereditary hemochromatosis. Heart failure is the most common cause of death in TM and primarily results from cardiac iron accumulation. The diagnosis of ventricular dysfunction in TM patients differs from that in nonanemic patients because of the cardiovascular adaptation to chronic anemia in non-cardiac-loaded TM patients, which includes resting tachycardia, low blood pressure, enlarged end-diastolic volume, high ejection fraction, and high cardiac output. Chronic anemia also leads to background symptomatology such as dyspnea, which can mask the clinical diagnosis of cardiac dysfunction. Central to early identification of cardiac iron overload in TM is the estimation of cardiac iron by cardiac T2* magnetic resonance. Cardiac T2* <10 ms is the most important predictor of development of heart failure. Serum ferritin and liver iron concentration are not adequate surrogates for cardiac iron measurement. Assessment of cardiac function by noninvasive techniques can also be valuable clinically, but serial measurements to establish trends are usually required because interpretation of single absolute values is complicated by the abnormal cardiovascular hemodynamics in TM and measurement imprecision. Acute decompensated heart failure is a medical emergency and requires urgent consultation with a center with expertise in its management. The first principle of management of acute heart failure is control of cardiac toxicity related to free iron by urgent commencement of a continuous, uninterrupted infusion of high-dose intravenous deferoxamine, augmented by oral deferiprone. Considerable care is required to not exacerbate cardiovascular problems from overuse of diuretics or inotropes because of the unusual loading conditions in TM. The current knowledge on the efficacy of removal of cardiac iron by the 3 commercially available iron chelators is summarized for cardiac iron overload without overt cardiac dysfunction. Evidence from well-conducted randomized controlled trials shows superior efficacy of deferiprone versus deferoxamine, the superiority of combined deferiprone with deferoxamine versus deferoxamine alone, and the equivalence of deferasirox versus deferoxamine.

Ineffective erythropoiesis in β -thalassemia

In humans, β-thalassemia dyserythropoiesis is characterized by expansion of early erythroid precursors and erythroid progenitors and then ineffective erythropoiesis. This ineffective erythropoiesis is defined as a suboptimal production of mature erythrocytes originating from a proliferating pool of immature erythroblasts. It is characterized by (1) accelerated erythroid differentiation, (2) maturation blockade at the polychromatophilic stage, and (3) death of erythroid precursors. Despite extensive knowledge of molecular defects causing β-thalassemia, less is known about the mechanisms responsible for ineffective erythropoiesis. In this paper, we will focus on the underlying mechanisms leading to premature death of thalassemic erythroid precursors in the bone marrow.

Morbidities and mortality in transfusion-dependent Beta-thalassemia patients (single-center experience)

BACKGROUND

The improvement of quality and duration of life of transfusion-dependent B thalassemia patients over the last years discloses several complications due to the underling disorder, iron overload and the treatment with iron chelators. Our Aim was to assess the morbidity patterns and mortality rate of transfusion-dependent thalassemia patients, and compare the outcomes in relation to age of onset, type, duration, and compliance to iron chelation therapy and frequency of blood transfusion.

PROCEDURE

This retrospective study included 447 transfusion-dependent β-thalassemia patients who attended the Thalassemia Center, Ain Shams University Children's Hospital over the last 10 years in the period between January 2000 and January 2010. Data were collected from the patients or their caregivers, as well as by reviewing follow up sheets for examinations and investigations done to detect morbidities as well as iron chelation therapies given. Determination of mortality rate and the causes of death were also done.

RESULTS

Results revealed that the most common morbidities were endocrinologic (44.7%) followed by cardiovascular (41.3%) and hepatic (40.5%), then renal (4%). The different iron chelation therapy groups showed a comparable prevalence of different morbidities. The mortality rate was 1.5% and infection was the most common cause of death. The 5, 10, 20 years' survival rate among the studied patients was 80%, 50%, 20%, respectively.

CONCLUSION

In the past 10 years, the survival and morbidity rates in our center have markedly improved as a result of regular blood transfusion, new iron chelators, and better compliance of the patients.

Deferasirox-induced renal impairment in children: an increasing concern for pediatricians

BACKGROUND

Deferasirox (DFX) is an oral iron chelator with an established dose-dependent efficacy in transfusion-related iron overload. Whereas emerging long-term data confirm the safety of the drug, with transient moderate elevation of serum creatinine level, several authors have reported renal tubular dysfunction. The aim of this study was to evaluate tubular and glomerular function before and after the initiation of DFX therapy in a pediatric patient population.

METHODS

Ten children (4 girls, mean age 12.4 ± 3.9 years) enrolled in a routine blood transfusion program were treated with 24.8 ± 9.6 mg/kg per day of DFX, and renal function was assessed before and 17.2 ± 8.9 months after the initiation of DFX therapy.

RESULTS

Prior to treatment with DFX, all patients had a normal glomerular function rate (GFR) (125 ± 15 ml/min per 1.73 m(2)) and normal tubular function. Following the initiation of DFX therapy, the GFR decreased by approximately 20 % with one patient with a GFR of <80 mL/min per 1.73 m(2) and seven patients with a GFR of <100 mL/min per 1.73 m(2). Two patients experienced a generalized proximal tubular dysfunction whereas nine patients presented at least one sign of proximal tubular dysfunction.

CONCLUSIONS

Renal toxicity is a frequent adverse event of DFX treatment, presenting as both glomerular and proximal dysfunction. A routine renal assessment is therefore required to prevent chronic kidney disease that may result from prolonged tubular injury.

Renal function in patients with β-thalassaemia major: a long-term follow-up study

BACKGROUND

Little information is available about the kidney's involvement in patients with β-thalassaemia major (TM). In particular, there are no studies reporting the outcome of renal function over time.

METHODS

In this retrospective study, we evaluated the changes in estimated glomerular filtration rate (eGFR) in 81 adult patients with TM followed for 10 years. Only patients who had an eGFR of >90 mL/min/1.73 m(2) at presentation were admitted to the study. All patients were regularly followed for at least 10 years.

RESULTS

At 10 years, 66 patients showed a mild decline in eGFR that remained, however, within a normal range (from 119.9 to 113.6 mL/min/1.73 m(2), P = 0.636). In the remaining 15 patients (18.5%), eGFR decreased to <90 mL/min (from 98.1 to 78.2 mL/min/1.73 m(2); P = 0.004). The repeated-measures models showed that the decline in eGFR over time was significantly higher (P = 0.0068) in patients with baseline phosphaturia >1000 mg/24 h (P = 0.0068), while eGFR tended to decline more rapidly in patients with baseline uricuria >700 mg/24 h than in those with lower uricuria (P = 0.0783). Univariate Cox's proportional regression models showed that abnormal levels of calcaemia were associated with the risk of kidney damage [hazard ratio (HR) 0.30, 95% confidence interval 0.09-0.97 for calcaemia 8.4-10.2 mg/dL versus HR not estimable for calcaemia <8.4 or >10.2 mg/dL].

CONCLUSIONS

In most adults with TM, the eGFR tends to remain within a normal range after 10 years. However, patients with elevated phosphaturia, elevated uricuria and/or abnormal levels of calcaemia show a significant decline in eGFR over time, suggesting that tubular damage acquired in childhood caused by either TM or its treatment may eventually result in abnormal eGFR. Further studies in a larger cohort of TM patients are needed to further elucidate the long-term impact of TM on renal function.

A case of hypophosphatemic osteomalacia secondary to deferasirox therapy

Patients with β-thalassemia major require iron-chelation therapy to avoid the complication of iron overload. Until recently, deferoxamine (DFO) was the major iron chelator used in patients requiring chronic hypertransfusion therapy, but DFO required continuous subcutaneous therapy. The availability of deferasirox (Exjade®), an orally active iron chelator, over the past 4 years represented a necessary alternative for patients requiring chelation therapy. However, there have been increasing reports of proximal renal tubular dysfunction and Fanconi syndrome associated with deferasirox in the literature. We report a case of hypophosphataemic osteomalacia secondary to deferasirox therapy.

Fok-I polymorphism of vitamin D receptor gene and the presence of renal dysfunction in patients with β-thalassemia major

Recent evidence supports the presence of renal dysfunction even among young patients with β-thalassemia major. However, the possible genetic contribution has never been investigated. The aim of this study was to correlate the presence of Fok-I polymorphism of the vitamin D receptor gene with abnormal levels of early markers of renal impairment in children and young adults with thalassemia. Thirty-four patients (19 male and 15 female) with β-thalassemia major on conventional treatment, with a mean decimal age of 14.62 ± 5.47 years (range: 5-22 years), were included in the study. Markers of renal function were determined in serum and in urine and patients were genotyped for Fok-I gene polymorphism. Genotype frequencies were similar to those previously reported for other populations: 47.06% of the patients were homozygous for the F allele, 41.18% were heterozygous, and 11.76% were homozygous for the f allele. A considerable number of patients demonstrated impaired renal function with increased serum cystatin C levels (29.41%), glomerular dysfunction with proteinuria (68%), as well as significant tubulopathy with hypercalciuria (73.08%), and increased levels of urinary β(2)-microglobulin (29.41%). When patients were stratified according to Fok-I polymorphism, a significantly higher prevalence of abnormally increased serum levels of cystatin C was observed in patients being homozygous for the f allele (75%) compared with those being heterozygous (Ff) or homozygous for the F allele (14.29% and 31.25%, respectively, P = .02). Further studies are needed to confirm these preliminary results and elucidate the possible mechanisms involved.

The effects of deferasirox on renal, cardiac and hepatic iron load in patients with β-thalassemia major: preliminary results

The iron loading related to erythrocyte transfusions is the major cause of morbidities and mortalities in patients with β-thalassemia major (β-TM). Deferasirox, an orally active iron chelator, has been reported to cause serum creatinine increases in addition to acute renal failures in elderly patients with comorbidities. The nefrotoxicities in patients using deferasirox, despite the facts that the drug is minimally excreted from kidneys and its effective chelation of iron from liver and heart, may rise the question of decomparmentalization of iron from these organs to kidneys. Thirteen patients with β-TM were included in the study (mean age 18.5 ± 7.5 years [9-33 years]). The patients received deferasirox in a dose of 34.3 ± 6.5 mg/kg [17-37 mg/kg]. Four patients (31%) exhibited consecutive increases in serum creatinine greater than 33% above baseline twice during the follow-up period. The results indicated that the earliest iron chelation starts in liver in patients receiving deferasirox. Additionally, by the 6th month of deferasirox, the status of cardiac and renal iron in chronically transfused patients with β-TM were preserved. This may indicate that the serum creatinine increases may not be attributed to iron decompartmantalization from other organs to kidneys.

Reversible Fanconi syndrome in a pediatric patient on deferasirox

Deferasirox (Exjade®, Novartis) is a widely used oral iron chelator for the treatment of patients with iron overload due to chronic transfusion therapy for diseases such as β-thalassemia and sickle cell disease. Renal side effects of deferasirox are common and include non-progressive increases in serum creatinine, however, the effect of deferasirox on proximal tubule function is unclear. We report one pediatric patient with reversible Fanconi syndrome associated with long-term deferasirox therapy and one patient with mild proximal tubular dysfunction. Kidney and proximal tubular function should be periodically monitored in patients receiving deferasirox throughout their course of therapy.

Renal dysfunction in patients with thalassaemia

Little is known about the effects of thalassaemia on the kidney. Characterization of underlying renal function abnormalities in thalassaemia is timely because the newer iron chelator, deferasirox, can be nephrotoxic. We aimed to determine the prevalence and correlates of renal abnormalities in thalassaemia patients, treated before deferasirox was widely available, using 24-h collections of urine. We calculated creatinine clearance and urine calcium-to-creatinine ratio and measured urinary β(2) -microglobulin, albumin, and protein. We used multivariate modelling to identify clinical, therapeutic, and laboratory predictors of renal dysfunction. One-third of thalassaemia patients who were not regularly transfused had abnormally high creatinine clearance. Regular transfusions were associated with a decrease in clearance (P = 0·004). Almost one-third of patients with thalassaemia had hypercalciuria, and regular transfusions were associated with an increase in the frequency and degree of hypercalciuria (P < 0·0001). Albuminuria was found in over half of patients, but was not consistently associated with transfusion therapy. In summary, renal hyperfiltration, hypercalciuria, and albuminuria are common in thalassaemia. Higher transfusion intensity is associated with lower creatinine clearance but more frequent hypercalciuria. The transfusion effect needs to be better understood. Awareness of underlying renal dysfunction in thalassaemia can inform decisions now about the use and monitoring of iron chelation.