Is It Necessary to Add Aprotinin Before Measuring The Level of Irisin in Serum and Plasma Samples?

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Şahin E., Handırı E., Altay D. U., Keha E. E.

Farabi Tıp Dergisi, vol.2, no.3, pp.1-5, 2023 (Peer-Reviewed Journal)


Irisin is a myokine with 112 amino acids and its blood concentration is regulated by peroxisome proliferator-activated receptor-γ coactivator1-α (PGC1-α). It is released into circulation from skeletal muscle tissue after a photolytic cleavage of extracellular domain of Fibronectin type III domain-containing protein 5 (FNDC5), a type I integral membrane protein. Aprotinin is a polyvalent serin protease inhibitor. It is added to sample solutions such as serum, plasma or tissue extracts in order to inhibit serine proteases found in the sample medium. Hence, degradation of the proteins to be measured can be prevented. This study has been carried out to obtain a preliminary data if any irisin loss could be seen in the serum samples which are kept at -80°C for a long duration. For this purpose, blood samples of 10 men and 10 women volunteers aged between 25-40 has been used. Aprotinin has been added to the plasma and the serum samples have been kept at -80°C for 3 months. At the end of 3 months, irisin levels of the samples with and without aprotinin have been determined by ELISA. Statistical analysis has shown no difference between the plasma samples with or without aprotinin (p=0.525). However, a significant decrease between the serum samples with and without aprotinin (p=0.009). In conclusion, with the results of this study, no net decision could have been achieved to add aprotinin to the samples for irisin determination with ELISA in plasma and serum kept at -80°C for about 3 months.