1. ASSOCIATION OF HYPOVITAMINAEMIA D AND TRANSFORMING GROWTH FACTOR – β1 IN THE PROGRESSION OF CHRONIC KIDNEY DISEASE Grigorios G. Dimas 1, Ilias E. Kanellos 1, Fotios S. Iliadis 1, Thomas J. Tegos 2, Sofia G. Spiroglou 3, Ioannis M. Karamouzis 3, Christos G. Savopoulos 1, Apostolos I. Hatzitolios 1, Dimitrios M. Grekas 1. 1 1st Propaedeutic Medical Department, AHEPA University Hospital, Aristotle University of Thessaloniki, Greece 2 1st Neurology Medical Department, AHEPA University Hospital, Aristotle University of Thessaloniki, Greece 3 Biochemistry Laboratory, AHEPA University Hospital, Aristotle University of Thessaloniki, Greece

2. Background The role of vitamin D in type 2 diabetes is well recognized, but its relation to glucose metabolism is not well studied. Transforming growth factor - β1 (TGF-β1) is involved nowadays in atherosclerosis and proteinuria. The aim of the present study was to determine the serum levels of 1.25(OH) 2 D 3 and TGF-β1 and to investigate their potential correlation with atherosclerotic markers and albuminuria in early stages of chronic kidney disease (CKD).

3. Aim The aim of the present study was to determine the serum levels of 1.25(OH) 2 D 3 and TGF-β1 and to investigate their potential correlation with atherosclerotic markers and albuminuria in early stages of chronic kidney disease (CKD).

4. Methods CKD patients of stages 1 and 2 (n=50) were included. As controls, there were healthy individuals (n=40). 1.25(OH) 2 D 3 and TGF-β1 levels were measured by an ELISA method. Intima media thickness (IMT) of carotid and femoral arteries and atheromatic plaque were evaluated by a high resolution ultrasonography.

5. Results There was a statistically significant difference between TGF-β1 (11000±500, p<0.0001), 1.25(OH) 2 D 3 (40±3, p<0.0001), albuminuria (300±150, p<0.0001) and IMT (0.4±0.1, p<0.0001) between patients and controls. There was a statistically significant positive strong correlation between levels of TGF-β1 and IMT (r= 0.75, p<0.0001) and TGF-β1 and albuminuria (r= 0.7, p<0.0001) in the patient group. There was also a statistically negative strong correlation between 1.25(OH) 2 D 3 and IMT (r= -0.7, p<0.0001), 1.25(OH) 2 D 3 and albuminuria (r= -0.75, p<0.0001) and 1.25(OH) 2 D 3 and TGF-β1 (-0.65, p<0.0001) in the patient group. Further, TGF-β1 and 1.25(OH) 2 D 3 levels were independently correlated with albuminuria, IMT and atheromatic plaque.

6. Conclusion Our study suggests that serum levels of TGF-β1 and 1.25(OH) 2 D 3 might present independent risk factors of atherosclerosis and albuminuria in CKD.