Telomerase stability and evaluation of real-time telomeric repeat amplification protocol.

Telomerase is RNA directed polymerase which acts as reverse transcriptase based on its own RNA component. It is considered to be involved in the pathology of many diseases and is recognized as a potential biomarker. The aims were to determine the sample storage conditions and the time frame for samples analysis, then to prove reliability of enzyme activity measurement with real-time telomeric repeat amplification protocol (TRAP) and to evaluate the suitable standard samples for telomerase activity measurements. Samples used for stability and freeze-thaw study were peripheral blood leukocytes, obtained from apparently healthy persons, patients with diagnosed cancer and cell lines. Telomerase activity was measured using TRAP method, while standard evaluation was done using nuclear magnetic resonance (NMR) technique. Storage at -20 °C preserved telomerase activity in samples from cancer patients for at least 14 days (21.46 ± 0.135 versus 21.84 ± 0.357, p = .756), while samples obtained from healthy persons should be stored at -80 °C. We observed significant decrease of telomerase activity at freeze thaw cycle 5 in cancer patients' samples (21.46 ± 0.135 versus 23.09 ± 0.316, p < .05), and in healthy persons' ones already at cycle 3 (22.74 ± 0.107 versus 24.85 ± 0.151, p < .05). Telomerase activity from cell lines samples showed overall greater stability regarding the storage period and freeze-thaw cycles and it was considered for standard sample, which was confirmed by NMR analysis. Telomerase enzyme had adequate stability while efficacy, linearity, and reproducibility of TRAP method were acceptable for bio-analytical methods. All this indicated that telomerase could be a reliable biomarker.

Cardiovascular Risk Factors in 7-13 Years Old Children from Vojvodina (Serbia).

BACKGROUND: Atherosclerosis is a chronic inflammatory disease which starts early in life and depends on many factors, an important one being dyslipoproteinemia. According to several studies, atherosclerotic plaques or their precursors could be seen in children younger than 10 years. During later life, interaction with a sedentary way of life, as well as unhealthy nutrition, smoking, alcohol consumption, obesity and family history of cardiovascular disease cause the burden of atherosclerotic disease. METHODS: Study included 624 children (316 boys, 308 girls), aged from 7-13 years. We analysed socio-demographic data (BMI, blood pressure, cardiovascular family history, smoking status), as well as lipid status with lipoprotein little a-Lp(a), and apolipoproteins: Apo AI, Apo B-100 for all children. This enabled us to calculate new atherogenic indices Tg/HDL-c, lipid tetrad index (LTI) and lipid pentad index (LPI). Cardiovascular risk for later life was estimated by using modified Risk Score for Young Individuals (RS), which divided the subjects according to the score level: low, medium and higher risk. RESULTS: The older children (13 y) had better lipid status than the younger children, i.e. significantly lower total cholesterol, LDL-C, triglycerides and non-HDL-C concentration and significantly higher HDL-C concentration than the younger children and this was in accordance with the RS level. Children with a positive family history of CV disease had significantly higher Lp(a) concentration and blood pressure. LPI was significantly higher in children with a higher RS. CONCLUSIONS: The results of our work could be used for cardiovascular risk assessment in apparently healthy children to provide preventive measures which could control the changeable risk factors.