Relationship between aging and control of metabolic syndrome with telomere shortening: a cross-sectional study (original) (raw)

Aging is considered one of the major risk factors for several human disorders. The telomere plays a crucial role in regulating cellular responsiveness to stress and growth stimuli as well as maintaining the integrity of the Deoxyribonucleic Acid (DNA), and aging leads to the progressive decline in the telomere length (TL) due to continuous cell division. The aim of this study was to determine the relationship between TL and advancing age and the impact of metabolic syndrome (MetS) on TL. Firstly, we determined the association of advancing age and TL, by measuring telomere length (T/S ratio) in healthy volunteers (n = 90). The TL was compared between normal population and patients with metabolic syndrome (n = 298). The age matched controlled and uncontrolled MetS patients (n = 149) were also compared for their TL T/S ratio. The TL showed negative correlation with advancing age, whereas the significant change was observed at the cutoffs of 40 and 70 years defining 40 with longer TL and 70 as shorter TL. The longest T/S ratio at 2.46 was measured at the age range of 1 year in healthy volunteers, while elderly population showed considerably shorter TL. The patients older than 60 years with poor or uncontrolled MetS had shorter TL, as compared to the controlled MetS. In conclusion our findings suggest that TL was negatively correlated with advancing age. Uncontrolled metabolic syndrome appeared to have worsening effects on TL. Telomere length appears to have potential to be used a parameter to determine age. However, further large scale studies are recommended to make firm guidelines. Aging is genetically characterized as the accretion due to modifications occurring over the period of time 1 , and it is also considered as one of the major risk factors for a number of human disorders 2. Globally, 150,000 individuals die daily and nearly 2/3rd of them die due to age related factors. Aging process however is not constant, but the process gets modified or expedited due to comorbidities such as, cardiovascular and metabolic disorders. Aging is a genetically controlled phenomenon, and telomeres are essential element to maintain the integrity of the genome and regulating cellular responses to stress and growth factors 3. In normal cells, under physiological conditions, the telomere length (TL) decreases with each cell division. Given that TL decreases with each cell division, it progressively shortens with advancing age, therefore can be considered a biological marker of aging. This age-related decline in TL has been associated with a number of age-related diseases, including hypertension, diabetes, cancer, Alzheimer's disease, and many others 4. In addition, there are number of factors that affect TL including oxidative stress, inflammation, and repetitive cell divisions, which correlate TL to chronological aging and age related diseases 5. The chronological age may differ from biological age due to comorbidities and other influencing factors. During normal cellular activities, free radicals and reactive oxygen species (ROS) are regularly generated. Excessive ROS formation causes oxidative damage and eventually leads to cell abnormalities and cell death. 6. Higher ROS levels, mitochondrial malfunction, additional double-strand Deoxyribonucleic Acid (DNA) breaks, and shortening of telomeres are indicators of cellular senescence 7. Furthermore, it was