Corresponding author: Zainab Fathi ( zainabh@uomosul.edu.iq ) Academic editor: Georgi Momekov
© 2021 Marwah Mohammed, Jehan Mohammad, Zainab Fathi, Muzahim Al-Hamdany, Nasih Alkazzaz.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Mohammed M, Mohammad J, Fathi Z, Al-Hamdany M, Alkazzaz N (2021) Comparative evaluation of cystatin C and neutrophil gelatinase-associated lipocalin in patients with thalassemia major versus thalassemia intermedia. Pharmacia 68(4): 741-746. https://doi.org/10.3897/pharmacia.68.e71475
|
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.
β-thalassemia, Cystatin C, Neutrophil gelatinase-associated lipocalin, Urea
Thalassemia is a genetic autosomal recessive disease widespread in the world, caused by a defect in globin synthesis that results in a reduced (β+) or absence (β0) production of β globin chain in haemoglobin (Hb) synthesis. Depending on the globin chains of Hb, thalassemia is categorized into α and β thalassemia (
Kidney disorders are long-term complications in thalassemia patients, especially with the high life expectancy of these patients. Proper evaluation of kidney impairment in 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. Nevertheless, conflicting results render it difficult to obtain definitive correlations and there are also no strong statistical diagnostic parameters for such biomarkers. For example, the ratio of albumin to creatinine may identify the initial signs of glomerulular disorder.
Cystatin C is a low-molecular-weight, non-glycosylated protein that is synthesized by all human cells and has the potential to inhibit lysosomal cysteine proteinases and papain (
Neutrophil gelatinase associated lipocalin is a 25 kDa protein which has been released by damaged nephron epithelia. It is considered a potential early renal biomarker for epithelial injury (
The aim of the current study is to compare the serum levels of urea, creatinine, cystatin C and NGAL in patients with β-thalassemia major versus intermedia, in addition to finding a significant correlation between these parameters. However, these early renal injury biomarkers have not yet been compared in these patients.
The current cross-sectional study was conducted on forty patients with thalassemia major, twenty-three patients with thalassemia intermedia and twenty-four healthy subjects as a control. The ages of the study groups ranged from 10 to 28 years, referred from Ibn Al-Atheer Centre in Mosul, between September 2019 and March 2020.
Patients with thalassemia major or intermedia who were over the age of 29 and receiving iron chelation therapy, such as deferoxamine and deferasirox, were excluded from the current study. Furthermore, thalassemia major patients with organ damage caused by drugs such as trimethoprim, steroids, and cephalosporins, or by other diseases such as diabetes mellitus, as well as patients with kidney or urinary tract disorders, were excluded. The healthy subjects did not have any diseases, such as autoimmune, infectious, neurological and pulmonary.
To measure the serum levels of urea and creatinine, blood samples were collected from the control and patient groups and immediately analysed. Whereas, to measure the serum levels of cystatin C and NGAL, blood samples were collected from the control and patient groups and serum was separated by centrifugation at around 3000 rpms for 10 mins at 4 °C. The obtained serum was stored at -80 °C for later use. The concentration of cystatin C and NGAL were estimated by enzyme linked immunosorbent assay (ELISA) using human Cys-C (cystatin C) and human NGAL (neutrophil gelatinase associated lipocalin) ELISA Kit (Elabscience, USA)
All values were set as mean ± SD. Ordinary one-way ANOVA followed by Tukey’s multiple comparisons test were used for data analysis of multiple comparisons, using GraphPad Prism version 8.0.2 (San Diego, USA). P < 0.05 were set statistically significant.
Forty patients (17 male and 23 female) with β-thalassemia major, twenty-three patients with (10 male and 13 female) with β-thalassemia intermedia and 25 subjects (12 male and 13 female) healthy control subjects were conducted in the present study, from September 2019 to March 2020. The mean age of the patients with β-thalassemia major was 17.28 ± 4.798 years, β-thalassemia intermedia was 16.22 ± 5.351 years and the control group was 18.80 ± 5.431 years. No significant variations (P > 0.05) were found between study groups with regard to age and sex.
Compared to control, serum levels of cystatin C and NGAL were markedly increased in both β-thalassemia major and intermedia. Moreover, serum levels of urea were significantly increased in thalassemia major compared to control, with no significant difference in β-thalassemia intermedia. However, no significant variation was noticed between thalassemia patients and control group in terms of serum creatinine levels. Compared to thalassemia intermedia, thalassemia major showed a significant increase in serum levels of NGAL and creatinine (Table
Parameters | Control | β-thalassemia major | β-thalassemia intermedia |
---|---|---|---|
Urea (mmol/l) | 4.016 ± 0.8184 | 4.588 ± 0.9143 a* | 4.191 ± 1.071 |
Creatinine (mmol/l) | 52.84 ± 11.62 | 55.25 ± 10.26 b** | 47.35 ± 6.307 |
Cystatin C (ng/ml) | 306.7 ± 69.03 | 385.4 ± 78.93 a** | 371.3 ± 101.8 a* |
NGAL (ng/ml) | 10.23 ± 1.728 | 18.40 ± 2.459 a**** b**** | 15.49 ± 1.219 a**** |
The life expectancy of thalassemia patients, in particular β-thalassemia major, has been recently improved with the appropriate therapeutic options, but new complications have been developed. The kidney is one of the vital organs affected by the regular blood transfusions in these patients, causing progressive iron accumulation and renal dysfunction. Moreover, subclinical renal impairment is known to develop early in thalassemia patients (
The accumulation of degradation products of Hb in the renal tubules in β-thalassemia patients results in renal tubular dilation, with subsequent mild to moderate proteinuria, haematuria and interstitial nephritis (
Lipocalin-2 (24p3r) and megalin are two receptors that allow NGAL to bind and produce its action on target cells. The 24p3r receptor is expressed in distal nephron and is responsible for protein endocytosis by NGAL uptake into the cell (
Several possible explanations can be contemplated for increased levels of NGAL in β-thalassemia patients, such as anaemia/chronic hypoxia, renal injury, and homeostatic iron disorders. Increased systemic levels of NGAL can be attributed to anaemia by causing direct inhibition of erythrocyte maturation. Hence, the autocrine regulatory pathway generated by local synthesis of NGAL by progenitors of immature medullary erythroid stem cells, and thus promoted by interleukin-1 that causes erythropoiesis inhibition by arresting of differentiation activation of apoptosis (
In the present study, levels of serum cystatin C were significantly increased in patients with β-thalassemia major and intermedia compared to control. We also found that cystatin C levels did not correlate with other biomarkers of renal dysfunction, suggesting a lack of activation of tubuloglomerular feedback (
In the current study, we concluded that cystatin C and NGAL could be used as specific, reliable and sensitive early predictors for renal dysfunction in patients with β-thalassemia major and intermedia, compared to conventional biomarkers (urea and creatinine).