Sağlıklı donörlerde trombositaferez işlemi sonrasında endojen trombopoetin seviyelerindeki değişiklikler
Date
2007
Authors
Özal, Güze
Journal Title
Journal ISSN
Volume Title
Publisher
Uludağ Üniversitesi
Abstract
Aferez yöntemiyle trombosit süspansiyonunun hazırlanması, transfüzyon tıbbında büyük bir avantaj saglamıstır. Aferez yöntemi trombosit süspansiyonu hazırlanması standart bir prosedür olmasına ragmen, donörden trombosit süspansiyonu alınması sonrasında, donörün trombosit sayısının normalizasyonunundan sorumlu regülatuvar mekanizmalar hakkındaki bilgilerimiz sınırlıdır. Megakaryopoezde anahtar sitokin olarak trombopoetinin kesfiyle (Trombopoetin (TPO) aynı zamanda mpl-ligand ve megakaryosit büyüme ve gelistirme faktörü-MGDF olarak da bilinir) trombosit üretiminin regülasyonu hakkında bilgi edinmemiz mümkün olmustur. Plazmadaki endojen TPO seviyeleri trombosit sayısı ile ters orantılıdır. Aplastik anemi, amegakaryositik trombositopeni veya kemik iligi transplantasyonu sonrası görülen trombositopenik durumlarda oldugu gibi megakaryosit aplazisinin oldugu durumlarda serum TPO seviyeleri belirgin olarak yüksektir. Tersine immün trombositopenik purpuralı hastaların serum TPO seviyeleri normal veya hafif yüksektir. Bu bulgular serum TPO seviyelerinin trombosit sayısından ziyade hem megakaryosit hem de trombosit kitlesiyle iliskili oldugunu göstermistir. Bu çalısmanın amacı, aferez islemi uygulanan saglıklı donörlerde trombosit kaybıyla iliskili olarak endojen TPO seviyelerinde degisiklik olup olmadıgını arastırmaktır. Çalısmaya ilk kez aferez islemi uygulanan 26 saglıklı donor alınmıstır. Serum TPO seviyeleri ve trombosit sayıları aferez islemi öncesi, islemin hemen sonrasında ve takip eden 4 gün boyunca ölçülmüstür. Serum TPO seviyeleri EL SA yöntemi kullanılarak ölçülmüstür. Bu çalısmada bazal serum TPO seviyeleri 30.21±13.03 pg/ml olarak bulunmustur. Aferez islemi sonrası trombosit sayısındaki en belirgin azalma islem sonrası ölçümde görülmüs ve trombosit sayısındaki artıs 1. günden itibaren baslamıstır. Ancak serum TPO seviyelerindeki artıs en belirgin olarak 4. günde meydana gelmistir (36.58±16.36 pg/ml). Aferez islemi sonrası donörün trombosit sayılarının normalizasyonu boyunca trombosit sayısı ile serum TPO seviyeleri arasında anlamlı bir iliski saptanamamıstır (p>0.05). Sonuç olarak aferez islemi sonrası meydana gelen trombosit sayısındaki normalizasyon ile serum TPO seviyeleri arasında iliski yoktur. Aferez islemi sonrası trombosit sayısındaki normalizasyon muhtemelen trombosit depo havuzu olan dalaktan trombositlerin dolasıma salınmasıyla meydana gelmektedir. Trombopoetin bu yanıtta geç dönemde etkili olabilir ya da megakaryosit sayısında azalma olmadıgı için minimal etkili olabilir.
The collection of single donor platelet concentrates by automated plateletpheresis has been a major advance in transfusion medicine. Although automated plateletapheresis is a standart procedure for the collection of single donor platelet concentrates, little is known about the regulatory mechanisms involved in the normalization of the donors’ platelet counts after platelet collection. Recent insights into the regulation of platelet production have been provided by the identification of thrombopoietin (TPO; also known as mpl-ligand and megakaryocyte growth and development factor-MGDF) as a key cytokine in megakaryocytopoiesis. The endogenous TPO levels in plasma are inversely correlated with the platelet counts. In patients with aplastic anemia, amegakaryocytic thrombocytopenia or after bone marrow transplantation, where thrombocytopenia is associated with megakaryocytopenic hypoplasia, TPO levels are extremly high. In contrast, patients with immune thrombocytopenic purpura (ITP) exhibit normal or only mildly elevated TPO levels. This datas indicated that serum TPO levels are more correlated with the combined megakaryocyte and platelet mass than with platelet numbers. The aim of this study was to test whether platelet donotion is associated with changes in the serum TPO levels in healthy donors undergoing plateletpheresis. The study group consisted of 26 healthy donors undergoing single donor plateletpheresis for the first time. Serum TPO levels and platelet counts were determined before platelet collection, at the end of apheresis, and for 4 days thereafter. Serum TPO levels were determined by a TPO specific enzyme linked immunosorbent assay. Baseline serum TPO levels were 30.21±13.03 pg/ml in this study. There was no significant correlation between serum TPO levels and platelet number during normalization of the donors’ platelet counts after plateletpheresis. In conclusion there is no correlation between serum TPO levels and normolization of platelet counts in response to plateletpheresis. Normalization of platelet counts after plateletapheresis may be ascribed to the release of platelets from the platelet storage pool, that is, the rapid mobilization of platelets from the spleen into the blood. Thrombopoietin may be affected late period in this response or may be minimally affected this response because megakaryocyte counts don’t decrease.
The collection of single donor platelet concentrates by automated plateletpheresis has been a major advance in transfusion medicine. Although automated plateletapheresis is a standart procedure for the collection of single donor platelet concentrates, little is known about the regulatory mechanisms involved in the normalization of the donors’ platelet counts after platelet collection. Recent insights into the regulation of platelet production have been provided by the identification of thrombopoietin (TPO; also known as mpl-ligand and megakaryocyte growth and development factor-MGDF) as a key cytokine in megakaryocytopoiesis. The endogenous TPO levels in plasma are inversely correlated with the platelet counts. In patients with aplastic anemia, amegakaryocytic thrombocytopenia or after bone marrow transplantation, where thrombocytopenia is associated with megakaryocytopenic hypoplasia, TPO levels are extremly high. In contrast, patients with immune thrombocytopenic purpura (ITP) exhibit normal or only mildly elevated TPO levels. This datas indicated that serum TPO levels are more correlated with the combined megakaryocyte and platelet mass than with platelet numbers. The aim of this study was to test whether platelet donotion is associated with changes in the serum TPO levels in healthy donors undergoing plateletpheresis. The study group consisted of 26 healthy donors undergoing single donor plateletpheresis for the first time. Serum TPO levels and platelet counts were determined before platelet collection, at the end of apheresis, and for 4 days thereafter. Serum TPO levels were determined by a TPO specific enzyme linked immunosorbent assay. Baseline serum TPO levels were 30.21±13.03 pg/ml in this study. There was no significant correlation between serum TPO levels and platelet number during normalization of the donors’ platelet counts after plateletpheresis. In conclusion there is no correlation between serum TPO levels and normolization of platelet counts in response to plateletpheresis. Normalization of platelet counts after plateletapheresis may be ascribed to the release of platelets from the platelet storage pool, that is, the rapid mobilization of platelets from the spleen into the blood. Thrombopoietin may be affected late period in this response or may be minimally affected this response because megakaryocyte counts don’t decrease.
Description
Keywords
Trombopoetin, Trombositaferez, Sağlıklı donörler, Thrombopoietin, Plateletapheresis, Healty donors
Citation
Özal, G. (2007). Sağlıklı donörlerde trombositaferez işlemi sonrasında endojen trombopoetin seviyelerindeki değişiklikler. Yayınlanmamış uzmanlık tezi. Uludağ Üniversitesi Tıp Fakültesi.