Telomere length and telomere repeat-binding protein in children with sickle cell disease

Mohamed E Suliman,Muaawia A Hamza,Abdullah A Saeed,Nasser M Al-Daghri,Mohammed G A Ansari,Abdul Khader Mohammed,Mohamed A Rayis

doi:10.1038/s41390-021-01495-6

Abstract

BackgroundThis study aimed to assess the telomere length and plasma telomere repeat-binding factor 2 (TRF2) levels in addition to other inflammatory markers in children with sickle cell disease (SCD).MethodsWe enrolled 106 children (90 SCD and 26 controls) aged 1–15 years from the Hematology unit of King Fahad Medical City (KFMC), Saudi Arabia. Genomic DNA extracted from blood and leukocyte TL was determined using quantitative reverse transcription PCR, whereas TRF2, C-reactive protein, interleukin-6, and DNA oxidative damage were determined by using respective commercially available assays.ResultsLeukocyte TL was inversely correlated with age in the SCD patients (r = −0.24, P = 0.02) and the controls (r = −0.68, P < 0.0001). In addition, SCD patients had significantly shorter TL (7.74 ± 0.81 kb) (P = 0.003) than controls (8.28 ± 0.73 kb). In contrast, no significant difference in TL among the SCD genotypes (HbSS and HbSβ0) has been observed. A modest, positive correlation was seen between TL and reticulocyte % (r = 0.21; P = 0.06). There were no significant differences in the TL and TRF2 concentrations between subjects with HbSS and HbSβ0 genotypes.ConclusionsShort leukocyte TL was significantly associated with SCD. An inverse association was observed between TL and hemoglobin. Hydroxyurea treatment revealed no impact on TL.ImpactThis study explored the TL and plasma TRF2 in Saudi children with SCD. This is the first documentation that SCD children have shorter TL than their healthy counterparts, and no association between TL and TRF2 has been observed.Hydroxyurea treatment showed no impact on TL in children with SCD.This study is the first of its kind in children with SCD.It will pave the way for another study with a larger sample size in a diverse population to scrutinize these findings better.

Highlights

Telomeres are noncoding nucleoprotein structures that cover the ends of repetitive nucleotide (TTAGGG) sequences and stabilize the genome[1,2] by capping chromosomal ends and protecting them from fusion and degradation
The current study was conducted on 90 sickle cell disease (SCD) (54% were males, with a mean age of 8 years) and 26 healthy children (48% males, with a mean age of 9 years)
The findings showed that there were no significant differences in the telomeric length (TL) and telomere repeat-binding factor 2 (TRF2) between both groups

Summary

Introduction

Telomeres are noncoding nucleoprotein structures that cover the ends of repetitive nucleotide (TTAGGG) sequences and stabilize the genome[1,2] by capping chromosomal ends and protecting them from fusion and degradation. Telomeres can span from 4 to 10 kb in human cells, depending on the chromosome cell type and genetic variation.[4] Each cell division leads to a telomere shortening (5–100 bp),[5,6] with the average rate of decline being more significant in men than in women.[7] This shortening continues until the telomere reaches a critical length,[8] which in turn triggers cell-cycle arrest, leading to senescence or apoptotic cell death. RESULTS: Leukocyte TL was inversely correlated with age in the SCD patients (r = −0.24, P = 0.02) and the controls (r = −0.68, P < 0.0001).

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