Homosistein metabolizma bozuklukları ve vasküler hastalıklarla ilişkisi
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Dosyalar
Tarih
2002
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
İnönü Üniversitesi Tıp Fakültesi Dergisi
Erişim Hakkı
Attribution 3.0 United States
Özet
Homosistein, metiyoninin metaboliti olan sülfürlü bir aminoasittir. İnsan plazmasında, hem sülfürlü indirgenmiş
(homosistein) hem de disülfidli oksidlenmiş (homosistin) formlarda bulunur. Homosisteinin okside formları
plazma total homosisteininin %98-99’unu oluşturmaktadır. Homosistein metabolizmasında, iki major yol vardır;
kofaktör olarak vitamin B12 kullanılarak metiyonine yeniden metillenebilir veya kofaktör olarak vitamin B6
kullanılarak sisteine dönüşebilir (transsülfürasyon). Bu reaksiyonlar, hücreler ve kandaki total homosistein (tHcy)
konsantrasyonunu düşürür. Erişkin erkek ve pediatrik populasyonda, ortalama açlık total homosisteini sırasıyla 5-
15 ve 3.7-10.3 mikromol/L arasındadır. Metiyoninden zengin, vitamin B’den fakir dietle beslenen erkeklerde,
yaşlılarda, böbrek fonksiyonu bozuk olanlarda ve homosistein metabolizmasına katılan enzimlerde genetik defekt
olanlarda plazma tHcy konsantrasyonu artmaktadır. Plazma tHcy’i ile dolaşımdaki folat ve vitamin B6
konsantrasyonları arasında zıt bir ilişki vardır. Günlük diete 0.5 mg folik asit eklenerek tHcy seviyeleri %25
azaltılabilmektedir. Son yıllarda yapılan vaka-kontrol çalışmalarında hiperhomosisteineminin koroner, serebral ve
periferik vasküler hastalıklar için kozal bir faktör olduğu tespit edilmiştir. Bu derlemede, homosistein,
homosistinüri ve kardiyovasküler hastalıklar arasındaki ilişkiler incelenmiştir.
Homocysteine is an aminoacid with that a sulfur-containing metabolite of methionine. Human plasma contains both reduced with sulfhydryl (homocysteine) and oxidized with disulphide (homocystine) forms of homocysteine. Oxidized forms of homocystein account for 98-99% of total homocysteine (tHcy). In the homocysteine metabolism, there are two major pathways. The first is remethylation back to methionine using vitamin B12 as cofactor. The second pathway is transsulfuration to cysteine using vitamin B6 as cofactor. These reactions reduce total homocysteine (tHcy) concentrations in cells and blood. Median fasting total homocysteine levels in adult males and pediatric populations are between 5-15 and 3.7-10.3 micromol/L, respectively. Increased plasma tHcy concentrations are found with methionine-rich diets, low vitamin B intake, male gender, increasing age, impaired renal function, and genetically determined defects of the enzymes involving in homocysteine metabolism. An inverse relation exists between plasma tHcy and circulating folate or vitamin B6 concentrations. Folic acid supplements of 0.5 mg/d can reduce tHcy levels by approximately 25%. In recent years, a number of casecontrol studies have established that hyperhomocysteinemia are a causal factor for coronary, cerebral, and peripheral vascular diseases. In this review, we analysed the inter relation between homocysteine and cardiovascular disease.
Homocysteine is an aminoacid with that a sulfur-containing metabolite of methionine. Human plasma contains both reduced with sulfhydryl (homocysteine) and oxidized with disulphide (homocystine) forms of homocysteine. Oxidized forms of homocystein account for 98-99% of total homocysteine (tHcy). In the homocysteine metabolism, there are two major pathways. The first is remethylation back to methionine using vitamin B12 as cofactor. The second pathway is transsulfuration to cysteine using vitamin B6 as cofactor. These reactions reduce total homocysteine (tHcy) concentrations in cells and blood. Median fasting total homocysteine levels in adult males and pediatric populations are between 5-15 and 3.7-10.3 micromol/L, respectively. Increased plasma tHcy concentrations are found with methionine-rich diets, low vitamin B intake, male gender, increasing age, impaired renal function, and genetically determined defects of the enzymes involving in homocysteine metabolism. An inverse relation exists between plasma tHcy and circulating folate or vitamin B6 concentrations. Folic acid supplements of 0.5 mg/d can reduce tHcy levels by approximately 25%. In recent years, a number of casecontrol studies have established that hyperhomocysteinemia are a causal factor for coronary, cerebral, and peripheral vascular diseases. In this review, we analysed the inter relation between homocysteine and cardiovascular disease.
Açıklama
İnönü Üniversitesi Tıp Fakültesi Dergisi
9(2) 149-157 (2002)
Anahtar Kelimeler
Homosistein, Vasküler Hastalık, Homosisteinemi, Homosistinüri, Homocysteine, Vascular Disease, Homocysteinemia, Homocystinuria
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Temel, İsmail ;Özerol, Elif ;İnönü Üniversitesi Tıp Fakültesi Dergisi 9(2) 149-157 (2002)
