Association between leukocyte telomere length and COVID-19 severity

Increased DNA damage/repair response in placentas from women infected with COVID-19 in pregnancy

INTRODUCTION

SARS-CoV-2 may induce DNA damage in infected cells. The objective of the study is to determine if maternal COVID-19 infection can induce cellular DNA damage in the placenta. We examined phospho-Histone H2AX (pH2AX) foci-positive cells, MRE11 expression, and telomere length (markers of DNA damage/repair) in placental specimens from women with or without COVID-19 infection during pregnancy.

METHODS

A total of 61 placental formalin-fixed paraffin embedded (FFPE) tissue specimens were used in the study, 33 in the COVID-19 group and 28 in the control group. Expression of pH2AX (Ser-139) and MRE11 was determined by immunostaining. Telomere length was assessed using the relative Human Telomere Length Quantification qPCR Assay Kit. Maternal demographic data was obtained via electronic medical record review. Data were analyzed by unpaired t-test or Chi-square test. A p level <0.05 was set statistically significant.

RESULTS

pH2AX foci-positive cells in the placentas were significantly higher in the COVID group than in the control group, p < 0.01; Relative expression of MRE11 was significantly increased in the COVID group (15.68 ± 1.57) than in the control group (5.74 ± 1.21), p < 0.01. In contrast, relative telomere length was significantly shorter in the COVID group (0.839 ± 0.123) than in the control group (1.652 ± 0.285), p < 0.05. The correlation of telomere length with placental weight and gestational age at delivery and the correlation of placental/newborn ratio were also analyzed.

CONCLUSIONS

Both pH2AX and MRE11 are biomarkers of DNA double-strand breaks. Telomeres are targets of a persistent DNA damage response, and reduced telomere length is an indicator of cellular senescence and aging. Our findings of increased pH2AX foci-positive cells and MRE11 expression and reduced telomere length in placental cells from women infected with COVID-19 in pregnancy provide plausible evidence that increased placental cellular DNA damage could be associated with maternal COVID-19 infection in pregnancy.

Leukocyte telomere length and telomerase activity in Long COVID patients from Rio de Janeiro, Brazil

BACKGROUND

Coronavirus disease 2019 (COVID-19) is caused by the new coronavirus 2 (severe acute respiratory syndrome coronavirus 2 - SARS-CoV-2). Long COVID is a new condition associated with persistent COVID-19 symptoms and/or new emerging symptoms. Telomeres are specialised structures for genome protection at the end of chromosomes and telomerase is the enzyme that synthesises telomere DNA.

OBJECTIVES

Patients with Long COVID symptoms were recruited at the Pedro Ernesto University Hospital (HUPE) in Rio de Janeiro, Brazil, with the main purpose of investigating the association between telomere length and Long COVID.

METHODS

Leukocyte telomere length (LTL) was determined by quantitative real-time polymerase chain reaction (qPCR) in 34 Long COVID patients compared to a control group (n = 122). Telomerase activity was determined by qPCR assays using the commercial kit from ScienCell. A questionnaire on symptoms, vaccine doses and blood count was completed.

FINDINGS

The Long COVID patients were found to have an increase in LTL. Telomerase activity was also examined in a smaller number of patients and found to be reactivated in the blood.

MAIN CONCLUSIONS

It will be necessary to conduct further studies and monitor Long COVID patients to determine if future health issues could be linked to telomerase activity and elongated telomeres.

Exploring the Relationship between Telomere Length and Cognitive Changes in Post-COVID-19 Subjects

BACKGROUND/OBJECTIVES

Emerging evidence suggests that patients suffering from COVID-19 may experience neurocognitive symptoms. Furthermore, other studies indicate a probable association between leukocyte telomere length (LTL) and neurocognitive changes in subjects with post-COVID-19 condition. Our study was designed to determine the correlation between telomere length and cognitive changes in post-COVID-19 subjects.

METHODS

This study included 256 subjects, categorized based on SARS-CoV-2 infection from 2020 to 2023. In addition, subjects with a psychiatric diagnosis were considered. Moreover, the MoCA and MMSE scales were applied. Telomere length was determined using a polymerase chain reaction, and statistical analysis was employed using ANOVA and X2 tests.

RESULTS

We identified a decrease in LTL in individuals with post-COVID-19 conditions compared to those without SARS-CoV-2 infection (p ≤ 0.05). However, no association was found between LTL and cognitive impairment in the subjects post-COVID-19.

CONCLUSIONS

The findings suggest that LTL is affected by SARS-CoV-2 infection. Nonetheless, this important finding requires further research by monitoring neurological changes in subjects with post-COVID condition.

GrimAge is elevated in older adults with mild COVID-19 an exploratory analysis

COVID-19 has been contained; however, the side effects associated with its infection continue to be a challenge for public health, particularly for older adults. On the other hand, epigenetic status contributes to the inter-individual health status and is associated with COVID-19 severity. Nevertheless, current studies focus only on severe COVID-19. Considering that most of the worldwide population developed mild COVID-19 infection. In the present exploratory study, we aim to analyze the association of mild COVID-19 with epigenetic ages (HorvathAge, HannumAge, GrimAge, PhenoAge, SkinAge, and DNAmTL) and clinical variables obtained from a Mexican cohort of older adults. We found that all epigenetic ages significantly differ from the chronological age, but only GrimAge is elevated. Additionally, both the intrinsic epigenetic age acceleration (IEAA) and the extrinsic epigenetic age acceleration (EEAA) are accelerated in all patients. Moreover, we found that immunological estimators and DNA damage were associated with PhenoAge, SkinBloodHorvathAge, and HorvathAge, suggesting that the effects of mild COVID-19 on the epigenetic clocks are mainly associated with inflammation and immunology changes. In conclusion, our results show that the effects of mild COVID-19 on the epigenetic clock are mainly associated with the immune system and an increase in GrimAge, IEAA, and EEAA.

Telomere length is an epigenetic trait - Implications for the use of telomerase-deficient organisms to model human disease

Telomere length, unlike most genetic traits, is epigenetic, in the sense that it is not fully coded by the genome. Telomeres vary in length and randomly assort to the progeny leaving some individuals with longer and others with shorter telomeres. Telomerase activity counteracts this by extending telomeres in the germline and during embryogenesis but sizeable variances remain in telomere length. This effect is exacerbated by the absence of fully active telomerase. Telomerase heterozygous animals (tert+/-) have reduced telomerase activity and their telomeres fail to be elongated to wild-type average length, meaning that - with every generation - they decrease. After a given number of successive generations of telomerase-insufficient crosses, telomeres become critically short and cause organismal defects that, in humans, are known as telomere biology disorders. Importantly, these defects also occur in wild-type (tert+/+) animals derived from such tert+/- incrosses. Despite these tert+/+ animals being proficient for telomerase, they have shorter than average telomere length and, although milder, develop phenotypes that are similar to those of telomerase mutants. Here, we discuss the impact of this phenomenon on human pathologies associated with telomere length, provide a brief overview of telomere biology across species and propose specific measures for working with telomerase-deficient zebrafish.