Katerina Kankova

Interleukin-17A Gene Variability in Patients with Type 1 Diabetes Mellitus and Chronic Periodontitis: Its Correlation with IL-17 Levels and the Occurrence of Periodontopathic Bacteria

Interleukin-17 contributes to the pathogenesis of type 1 diabetes mellitus (T1DM) and chronic periodontitis (CP). We analyzed IL-17A −197A/G and IL-17F +7488C/T polymorphisms in T1DM and CP and determined their associations with IL-17 production and occurrence of periopathogens. Totally 154 controls, 125 T1DM, and 244 CP patients were genotyped using 5′ nuclease TaqMan® assays. Bacterial colonization was investigated by a DNA-microarray kit. Production of IL-17 after in vitro stimulation of mononuclear cells by mitogens and bacteria was examined by the Luminex system. Although no differences in the allele/genotype frequencies between patients with CP and T1DM + CP were found, the IL-17A −197 A allele increased the risk of T1DM (P < 0.05). Levels of HbA1c were significantly elevated in carriers of the A allele in T1DM patients (P < 0.05). Production of IL-17 by mononuclear cells of CP patients (unstimulated/stimulated by Porphyromonas gingivalis) was associated with IL-17A A allele (P < 0.05). IL-17A polymorphism increased the number of Tannerella forsythia and Treponema denticola in patients with CP and T1DM + CP, respectively (P < 0.05). IL-17A gene variability may influence control of T1DM and the “red complex” bacteria occurrence in patients with CP and T1DM + CP. Our findings demonstrated the functional relevance of the IL-17A polymorphism with higher IL-17 secretion in individuals with A allele.

Three novel polymorphisms in the promoter region of the TIMP-3 gene are not associated with proliferative diabetic retinopathy in type 2 diabetes mellitus.

Purpose. Tissue inhibitor of metalloproteinase-3 (TIMP-3) is a member of the TIMP family of proteins, playing a significant role in the control of extracellular matrix remodelling. TIMP-3 might play a role in the regulation of retinal neovascularization during progression of diabetic retinopathy. Recently, three novel polymorphisms (-899T/A, -915A/G and -1296T/C) in the promoter region of the TIMP-3 gene have been identified. The aim of the study was to investigate a possible association of these polymorphisms with proliferative diabetic retinopathy (PDR) in type 2 diabetes mellitus (T2DM). Methods. Genotypes were detected by polymerase chain reaction and subsequent restriction with specific endonucleases. Allele frequencies were determined in an association study comprising three groups of subjects (n = 371). Results. Linkage disequilibrium was found among the three polymorphisms (P = 0.01). Allele frequencies did not differ between neither T2DM + PDR and T2DM non-PDR subjects (P > 0.05) nor between all T2DM versus non-diabetic subjects (P > 0.05). Conclusions. Polymorphisms in the promoter region of the TIMP-3 gene were not associated with the PDR in the Caucasian T2DM patients.

Levels of heavy metals and their binding protein metallothionein in type 2 diabetics with kidney disease

Hyperglycemia, a major metabolic disturbance present in diabetes, promotes oxidative stress. Activation of antioxidant defense is an important mechanism to prevent cell damage. Levels of heavy metals and their binding proteins can contribute to oxidative stress. Antiradical capacity and levels of metallothionein (MT), metals (zinc and copper), and selected antioxidants (bilirubin, cysteine, and glutathione) were determined in 70 type 2 diabetes mellitus (T2DM) subjects and 80 healthy subjects of Caucasian origin. Single nucleotide polymorphism (rs28366003) in MT gene was detected. Antiradical capacity, conjugated bilirubin, and copper were significantly increased in diabetics, whereas MT and glutathione were decreased. Genotype AA of rs28366003 was associated with higher zinc levels in the diabetic group. The studied parameters were not influenced by renal function. This is the first study comprehensively investigating differences in MT and metals relevant to oxidative stress in T2DM. Ascertained differences indicate increased oxidative stress in T2DM accompanied by abnormalities in non‐enzymatic antioxidant defense systems.