Yıldıray KARACA, Sadık ULUSOY, Tuğba EMÜROĞLU, Safiye Can KÜÇÜKGÜL, Füsun ERCİYAS

Diyabetik retinopatisi olan tip 2 diabetes mellituslu hastalarda,serbest insülin benzeri büyüme faktörü-I'i yansıtan,insülin benzeri büyüme faktörü-I/ insülin benzeri büyüme faktörü bağlayıcı protein-3 oranı

Amaç: Diyabetik retinopatili hastalarda serumda total insülin benzeri büyüme faktörü-I (IGF-I) düzeylerindeki artışın, hastalığın gelişiminde önemli olduğu düşünülmektedir. Literatürde diyabetik retinopatili hastalarda IGF-I’nın biyolojik etkilerine aracılık eden, serbest IGF-I düzeylerini ölçen çalışmalar çok azdır. Bir çalışmada insülin benzeri büyüme faktörü-I / insülin benzeri büyüme faktörü bağlayıcı protein-3 (IGF-I / IGFBP-3) oranının serbest IGF-I’i yansıttığı bildirilmiştir. Biz de çalışmamızda IGF-I / IGFBP-3 oranını kullanarak, serbest IGF-I ile diyabetik retinopati arasındaki ilişkiyi araştırmayı amaçladık. Gereç ve yöntem: Çalışmaya 40-70 yaş arası tip 2 diabetes mellitusu (DM) olan hastalar alındı. Diyabetik retinopatisi olan tip 2 DM’liler (n = 20), diyabetik retinopatisi olmayan tip 2 DM’liler (n = 20) ve sağlıklı kontrol grubu (n = 20) olmak üzere 3 grup oluşturuldu. Diyabetik retinopati tanısı fundus floresein anjiyografi ve/veya oftalmaskopik inceleme ile konuldu. Alınan kan örneklerinden elde edilen serumlarda total IGF-I ve IGFBP-3 düzeyleri immunoradiyometrik (IRMA) yöntem ile ölçüldü ve IGF-I / IGFBP-3 oranı hesaplandı. Bulgular: Total IGF-I ve IGFBP-3 düzeyleri açısından gruplar karşılaştırıldığında, aralarında istatistiksel olarak anlamlı bir fark bulunmadı. IGF-I / IGFBP-3 oranları diyabetik retinopatili ve diyabetik retinopatisiz tip 2 DM’li gruplarda, kontrol grubuna göre daha yüksek olmakla birlikte, bu farkın istatistiksel olarak anlamlı olmadığı saptandı. Sonuç: Buna göre bizim çalışmamızda serbest IGF-I’nın göstergesi olarak kullanılan serum IGF-I / IGFBP-3 oranı ile diyabetik retinopati arasında bir ilişki olmadığı sonucuna varıldı. Ancak IGF sisteminin diğer bileşenlerini de içeren daha ayrıntılı ve ileri çalışmalara ihtiyaç olduğunu düşünmekteyiz.

Anahtar Kelimeler:

İnsülin-benzeri büyüme faktörü I, Diabetes mellitus, tip 2, Diabetik retinopati, İnsülin-benzeri büyüme faktörü bağlayıcı protein 3

The ratio of insulin-like growth factor-I/ insulin-like growth factor binding protein-3 which reflects free insulin-like growth factor-I in patients with type 2 diabetes mellitus with diabetic retinopathy

Objective: Increase in serum total insulin-like growth factor-I (IGF-I) is considered as a major pathogenetic factor in the development of diabetic retinopathy. The biological effects of IGF-I are mediated by free IGF-I. Studies investigating free IGF-I concentrations are rare. The ratio of IGF-I /TGFBP-3 (insulin-like growth factor binding protein-3) is reported to reflect free IGF-I concentrations. In the present study, IGF-I/IGFBP-3 ratio is used to investigate the relationship between free IGF-I levels and diabetic retinopathy. Material and method: 40 patients whose ages were ranging between 40 and 70 with type 2 diabetes mellitus (DM) were equally divided into two subgroups according to presence of diabetic retinopathy and 20 healthy individuals were enrolled controls. The diagnosis of diabetic retinopathy was established by fundus fluorescein angiography and/or ophtalmoscopic examination. Serum total IGF-I and IGFBP-3 levels were measured by immunoradiometric assay (IRMA) and the ratio of IGF-I/IGFBP-3 was calculated. Results: Serum total IGF-I and IGFBP-3 levels did not differ between the two diabetic groups and controls. IGF-I/IGFBP-3 ratio appeared to be slightly higher in both diabetic groups, compared to controls, but the difference was not significant. Conclusion: It was concluded that, no association existed between serum IGF-I/IGFBP-3, a marker of free IGF-I, and diabetic retinopathy. Other constituents of the IGF system must be measured to assess this relationship.

Keywords:

Insulin-Like Growth Factor I, Diabetes Mellitus, Type 2, Diabetic Retinopathy, Insulin-Like Growth Factor Binding Protein 3,

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