Elif ŞAHİN, Ecem HANDIRI, Diler US ALTAY, Eşref Edip KEHA

Serum ve Plazma Örneklerinde İrisin Seviyesini Ölçmeden Önce Aprotinin İlave Etmek Gerekir mi?

İrisin, miktarı peroksizom proliferatörü ile aktive edilen reseptör gama koaktivatör1-α (PGC1-α) tarafından düzenlenen, 112 aminoasitten oluşan bir miyokindir. Bir tip I integral membran proteini olan fibronektin tip III domeini içeren protein 5’in (FNDC5) proteolitik parçalanması sonucu iskelet kası dokusundan kan dolaşımına salınır. Aprotinin çok değerlikli bir serin proteaz inhibitörüdür. Serum, plazma veya hücre homojenizatı gibi sulu çözelti örneklerine eklenerek, ortamda bulunan serin proteaz enzimlerini inhibe eder. Bu şekilde, ölçümü yapılacak olan proteinlerin parçalanması önlenir. Çok defa -80°C’de uzun süre saklanma ihtiyacı duyulan örneklerde irisin kaybının olup olmayacağı hakkında bir ön bilgi elde etmek amacı ile bu çalışma yapılmıştır. Bu amaçla, 25-40 yaş arasında 10 erkek ve 10 kadın gönüllüden kan örnekleri alınmış ve bunlardan elde edilen plazma ve serum örneklerine aprotinin eklenerek 3 ay -80°C’de saklanmıştır. 3 ay sonra, ELISA ile aprotininli ve aprotininsiz örneklerde irisin seviyeleri ölçülmüştür. Sonuçların istatistiksel değerlendirilmesiyle, aprotininli ve aprotininsiz plazma örneklerindeki irisin miktarlarında önemli bir farklılık olmadığı gözlemlenirken (p=0.525), aprotininli ve aprotininsiz serum örneklerindeki irisin miktarlarında anlamlı bir azalma bulunmuştur (p=0.009). Sonuç olarak, ELISA ile irisin tayin edilmek üzere 3 ay civarında -80°C’de saklanan plazma ve serum numunelerine aprotinin eklenmesinin gerekip gerekmediği konusunda net bir kanaate varılamamıştır.

Anahtar Kelimeler:

Aprotinin, İrisin, Serin Proteaz

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

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.

Keywords:

Aprotinin, Irisin, Serine Protease,

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