| Objective:This study aimed to investigate the variation of leukocytes telomere length of healthy population in different age groups with increasing age; investigate the correlation between kidney function with telomere length of the different age groups of healthy population in Beijing and telomere shortening during follow-up. Methods:In this study, with the method of random cluster sampling, a total of 1207 cases of healthy volunteers in Beijing area participated in the health survey in 2014. According to the strict inclusion and exclusion criteria, while balancing the sex ratio, selected 471 cases of healthy people in different age groups to measure leukocytes telomere length. 80 cases of healthy people was a longitudinal profile in 2011. The healthy people peripheral blood leukocytes were obtained and the telomere restriction fragment length(TRF) length was assayed using a digoxigenin-labeled hybridization probe in Southern blotting assays. Measures of kidney function included: serum creatinine, serum cystatin C, Cockcroft-Gault equation to estimate glomerular filtration rate(e GFRC-G), cystatin C-derived estimated glomerular filtration rate(e GFRcys), united creatinine and cystatin C derived estimated glomerular filtration rate(e GFRScr-cys) and creatinine-derived estimated glomerular filtration rate(e GFRCKD-EPI). We calculated the rate of change of TRF over three years, the rate of change in TRF=[(later TRF-baseline TRF)/baseline TRF]×100%. According to the situation that telomere lengths may change, we define the length of the three kinds of changes: rise(≥1%), no change(greater than-1% and less than 1%), and fall(≤-1%). The subjects in 2014 were divided into five different age groups by 10-year age groups: 35-44 years, 45-54 years, 55-64 years, 65-74 years and >75years. 80 cases of longitudinal cohort, the ranges for the quartiles of baseline telomere length were as follows: quartile 1(8.739-7.409kb), quartile 2(7.403-6.943kb), quartile 3(6.908-6.490kb) and quartile 4(6.484-5.208kb). Linear regression models were used to test the association of kidney function with baseline telomere length and change in telomere length over 3 years. Results:1. Study found that in 2014 healthy people in Beijing of different age groups peripheral blood leukocyte telomere length was negatively correlated with age, the correlation coefficient r=-0.393, p<0.001. Compared leukocytes telomere length of each age groups showed old group was significantly lower than the younger group, telomere length differences were statistically(p<0.05). And the average level of telomere length of women was longer than men(p=0.011).2. The analysis of 471 cases in 2014 healthy human TRF length and renal function showed TRF length was negatively correlated with cys C, and was positively correlated with e GFRCKD-EPI, e GFRC-G, e GFRcys and e GFRScr-cys(p<0.01).3. Longitudinal cohort analysis found that, in 2011 the average TRF length of 80 participants was 6.893±0.642 kb, in 2014 average TRF length was 6.755±0.573 kb, over the 3 years, the telomeres lost on average 138 bp in length, corresponding to a mean loss of 46 bp per year. Among them, telomere shortening was observed in 73% of participants; telomere maintenance was observed in 11% of participants; and telomere lengthening was observed in 16% of participants.4. In 80 cases of longitudinal cohort, the change of telomere length between different groups shows that, telomere length changes in quartile 1 was significantly higher than quartile 2, quartile 3 and quartile 4 group; telomere length changes in quartile 2 was significantly higher than quartile 4.5. Changes in telomere length of 80 participants during the 3-year follow-up were related to telomere length in 2011 and in 2014. After adjustment for age, the change in telomere length was significantly associated with telomere length in 2011.6. Correlation analysis were performed on changes of telomere length during 3 years of follow-up and renal function, the results showed that telomere shortening only related with cys C in 2014; However, after adjustment for age, this association was no longer significant. In addition, changes of telomere length were not associated with changes of renal function during the follow-up. Conclusion:1. Cross-sectional analysis confirms the conclusion that human peripheral blood leukocyte telomere length was negatively correlated with age. Longitudinal studies found that telomere length overall presentation is decreasing, but there are individual differences.2. Human peripheral blood leukocyte telomere length was significantly correlated with renal function; but the change in telomere length during the 3-year follow-up was only associated with cys C in 2014, after adjustment for age, the association was no longer statistically significant.3. During the 3-year follow-up, the change in telomere length was mainly affected by the baseline telomere length, and decreased kidney function was not relevant to shortening of telomere length over 3 years. |
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