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

Renal Dysfunction in Pediatric Patients in Iraq With β-Thalassemia Major and Intermedia

Background

With optimum transfusion and chelation therapy, the survival of β-thalassemia patients and the incidence of various complications, including renal complications, have improved.

Objectives

To investigate renal involvement in β-thalassemia patients using serum and urinary biochemical markers of glomerular and tubular dysfunction.

Methods

This case-control study included 69 β-thalassemia major (β-TM) patients, 23 β-thalassemia intermedia (β-TI) patients, and 100 healthy controls, all ranging from 1 to 16 years in age. Blood urea nitrogen (BUN), serum ferritin, serum and urinary levels of creatinine (Cr), uric acid (UA), calcium (Ca), phosphorus (Ph), magnesium (Mg), sodium (Na), and potassium (K), and the urinary albumin/creatinine ratio were evaluated.

Results

The BUN level and the urinary Na/Cr, K/Cr, Ca/Cr, Mg/Cr, Ph/Cr, albumin/Cr, and UA/Cr ratios were significantly higher in the β-thalassemia patients than in the controls. In contrast, the serum Na, K, Ca, and Mg levels were significantly lower in the patients (P<0.05). An elevated urinary UA/Cr ratio was found in 61.9% of β-thalassemia patients, and an elevated urinary Ca/Cr, and urinary albumin/Cr ratio was found in 53.2%. An elevated Na/Cr ratio was found in 41.3%. The serum and urinary renal markers showed no significant differences between patients with β-TM and β-TI, except for microscopic hematuria, which was significantly higher in β-TI patients (34.8%) than in β-TM patients (13%), P>0.02. At an older age, high serum ferritin levels and deferoxamine therapy were associated with significant tubular and glomerular dysfunction in β-thalassemia patients.

Conclusions

Pediatric patients with β-thalassemia have significantly abnormal tubular and glomerular functions, necessitating early detection and monitoring to prevent/reverse renal function deterioration.

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.

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

Objective

Beta(β)-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.

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.

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.

Renal function and the oxidative status among children with thalassemia major and healthy controls: A cross-sectional study

BACKGROUND

Renal dysfunction is an underestimated complication of thalassemia major.

OBJECTIVES

The aim of this study is to compare the glomerular and tubular functions in children with β- Thalassemia major (β- TM) with healthy controls and assess the oxidative stress caused by high ferritin levels.

DESIGN AND SETTING

This prospective cross-sectional study was conducted in tertiary care hospital.

METHODS

Complete blood count (CBC), calcium (Ca), urea, creatinine (Cr), serum cystatin C before transfusion and urinary calcium (uCa), creatinine (uCr), protein (UPr) levels were analyzed in fresh samples. Beta-2-microglobulin (uβ2-MG), N- acetylglucosaminidase (uNAG), retinol binding protein (uRBP), malonedialdehyde (uMDA) secretion and creatinine levels were analyzed. Serum total antioxidant capacity (sTAC) and total oxidant capacity (sTOC) were measured with colorimetric micro-ELISA method. Last four serum ferritin values were recorded and the mean value was used for statistical analyzes.

RESULTS

Data from 47 patients and 32 controls were analyzed. The urinary RBP/Cr, Ca/Cr and Protein/Cr, were significantly higher in β-TM group. A statistically insignificant increase in urinary β2MG/Cr, uNAG/Cr, MDA/Cr was also found in the TM group. Proteinuria was present in 46 % (n: 22) and hypercalciuria in 34 % (n: 16) of the patients with β- TM. Serum total antioxidant capacity and total oxidant status (TOS) levels were significantly elevated in the patient group. Serum ferritin was significantly correlated with proteinuria, cystatin C levels, urinary Protein/Cr and uRBP/Cr.

CONCLUSION

Asymptomatic renal dysfunction is prevalent in β- TM patients that necessitate regular screening. Urinary RBP may be useful for early diagnosis.

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.

Genotype-phenotype Correlation of β-Thalassemia in Croatian Patients: A Specific HBB Gene Mutations

An analysis of genotype-phenotype correlation was performed for 14 patients with beta-thalassemia who had been registered in Referral Centre for hematology and oncology of the University Hospital Centre, Zagreb, Croatia. HBB gene mutations were determined using a gene-specific Q5 High-Fidelity PCR analysis with direct DNA sequencing of amplified transcripts. Mahidol score index used for classification of thalassemia severity was found to be low for all the patients enrolled in the study, indicating a mild β-thalassemia phenotype with no signs of disease progression. Most of the patients have already described gene mutations: IVS-II-666 C>T (HBB:c.316-185C>T) and IVS-II-16 G>C (HBB:c.315+16G>C). Each of the aforementioned mutations was found in (11/14; 78,57%) and (10/14; 71,43%) of our patients, respectively. Recently published HBB:c.9T>C mutation was found in 8 of 14 (57,14%) in our study group. IVSII-74 T>G (HBB:c.315+74T>G) is a worldwide mutation found in 6 of 14 (42.86%) of our patients. All these mutations occur among Croatian children with no obvious Indian/Near Eastern/Iranian ancestry. We also identified 7 de novo mutations (c.316-135het_dupT, c.316-133A>G, c.93-54G>A, c.316-68_316-67het_insCGG, c.316-342delA, c.316-312delT, c.316-209delT) of mild severity phenotype according to Mahidol classification score index. We did not find children or adults with thalassemia major severity phenotype.