Browsing by Author "Demirag, Nilgun Guvener"

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Cystatin-C and TGF-beta levels in patients with diabetic nephropathy
(2016) Takir, Mumtaz; Unal, Asli Dogruk; Kostek, Osman; Bayraktar, Nilufer; Demirag, Nilgun Guvener; 0000-0002-7886-3688; 27745866; Y-8758-2018
Objective: To evaluate renal impairment in type 2 diabetic patients with normoalbuminuria or microalbuminuria by detection of serum cystatin C and serum and urinary TGF-beta levels. Methods: Cross-sectional study conducted at the Department of Endocrinology in Baskent University School of Medicine. Patients with type 2 diabetes mellitus without known overt diabetic nephropathy were included in the study. Recruited patients were stratified into four groups, matched in terms of age, gender, microalbuminuria level and estimated GFR calculated with MDRD. Results: 78 patients were enrolled. They were categorized into four groups depending on their urinary albumin excretion and estimated glomerular filtration rate. Macrovascular complication was found to be higher in patients with microalbuminuria than in other patients (p < 0.01), but there were no differences in terms of other diabetic complications. Serum cystatin C level was significantly higher in normoalbuminuric group one patients, while serum and urinary TGF-beta 1 levels were higher in microalbuminuric group two patients. The serum level of cystatin C was found to negatively correlate with eGFR in group two patients (r = -0.892, p < 0.001). Finally, there was a negative correlation between eGFR and cystatin C in all the patient groups (r = -0.726, p=0.001). Conclusions: Although urinary albumin excretion is recommended for the detection of type two diabetic nephropathy, there is a group of patients with decreased eGFR but without increased urinary albumin excretion, in which serum cystatin C level was indicated to be used as an early biomarker of diabetic nephropathy. (C) 2016 Published by Elsevier Espana, S.L.U. on behalf of Sociedad Espanola de Nefrologia.
Insulin Resistance in Non-Obese Polycystic Ovary Syndrome Subjects and Relation with Family History of Diabetes Mellitus
(2015) Bozkirli, Emre; Bakiner, Okan; Ertorer, Eda; Anaforoglu, Inan; Tutuncu, Neslihan Basil; Demirag, Nilgun Guvener
Purpose: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women in reproductive age. Conflicting results are reported in the studies examining insulin resistance in lean PCOS subjects. We aimed to observe the controversial presence of insulin resistance in lean PCOS subjects with the gold standard method and assess the impacts of family history of type 2 diabetes mellitus (T2DM) on insulin resistance in these patients. Material and Method: Nineteen patients with PCOS and nine age-BMI matched control subjects were recruited into the study. Patients with PCOS were divided into two groups according to their FH of T2DM among their first degree relatives (FHneg vs FHpos). Insulin resistance was evaluated with homeostasis model assessment of insulin resistance (HOMA-IR) and hyperinsulinemic euglycemic clamp technique for all participants. Results: Mean M values were significantly higher in the control group when compared with PCOS patients (p=0.003). There was no statistically significant difference for HOMA-IR and M values when FHneg and FHpos patients were compared. Although HOMA-IR values were similar between all groups, M values were lower in FHneg and FHpos groups compared to the controls (p=0.02 and 0.004 respectively). Discussion: Lean PCOS patients have evident insulin resistance when compared to healthy subjects, and FH of T2DM seems to not affect insulin resistance. Even non-obese PCOS patients should be encouraged for healthy eating style and exercise to prevent the potential risks associated with insulin resistance. Furthermore these patients can see benefits from medical therapies which improve insulin sensitivity.
Vitamin D deficiency is related to thyroid antibodies in autoimmune thyroiditis
(2014) Unal, Asli Dogruk; Tarcin, Ozlem; Parildar, Hulya; Cigerli, Ozlem; Eroglu, Hacer; Demirag, Nilgun Guvener; 26155169
Introduction: It has been known that vitamin D has some immunomodulatory effects and in autoimmune thyroid diseases, vitamin D deficiency was more prevalent. In this study, our aim was to investigate the relationship between thyroid autoantibodies and vitamin D. Material and methods: Group 1 and 2 consisted of 254 and 27 newly diagnosed Hashimoto's thyroiditis (HT) and Graves' disease (GD) cases, respectively; age-matched 124 healthy subjects were enrolled as controls (group 3). All subjects (n = 405) were evaluated for 25OHD and thyroid autoantibody [anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-tg)] levels. Results: Group 2 and group 1 patients had lower 25OHD levels than group 3 subjects 14.9 +/- 8.6 ng/ml, 19.4 +/- 10.1 ng/ml and 22.5 +/- 15.4 ng/ml, respectively (p < 0.001). Serum 25OHD levels inversely correlated with anti-tg (r = -0.136, p = 0.025), anti-TPO (r = -0.176, p = 0.003) and parathormone (PTH) (r = -0.240, p < 0.001). Group 2 patients had higher anti-tg and anti-TPO levels than group 1 and 3 (p < 0.001). Conclusions: In this study, we found that patients with autoimmune thyroid disease (AITD) present with lower vitamin D levels and GD patients have higher prevalence. Since we found an inverse correlation between vitamin D levels and thyroid antibody levels, we may suggest that vitamin D deficiency is one of the potential factors in pathogenesis of autoimmune thyroid disorders