Fatmahan Atalar

Presence of fatty-acid-binding protein 4 expression in human epicardial adipose tissue in metabolic syndrome.

BACKGROUND Metabolic syndrome is a cluster of different clinical manifestations that are risk factors for atherothrombotic cardiovascular disorders. Fatty-acid-binding protein 4 (FABP4/aP2), which is highly expressed in adipocytes, specifically exerts intracellular lipid trafficking. A high level of fatty-acid-binding protein 4 expression present in obese subjects has also been found in mice and humans, especially in macrophages at atherosclerotic lesions. An in vivo study demonstrated that the inhibitor of aP2 would be a new therapeutic agent for treating metabolic diseases in mice. We have investigated the mRNA expression of fatty-acid-binding protein 4 in human epicardial adipose and ascending aorta tissues of metabolic syndrome and nonmetabolic syndrome patients. METHODS Paired epicardial adipose and ascending aorta tissue samples were obtained from 10 metabolic syndrome patients and 4 nonmetabolic syndrome patients during coronary bypass grafting and aortic valve replacement therapy, respectively. Fatty-acid-binding protein 4 gene expression was determined by quantitative real-time polymerase chain reaction. RESULTS AND CONCLUSIONS Fatty-acid-binding protein 4 expression of epicardial adipose tissue was significantly higher in metabolic syndrome patients than in nonmetabolic syndrome controls (P<.05). In metabolic syndrome patients, fatty-acid-binding protein 4 expression in epicardial adipose tissue was 66 times higher than fatty-acid-binding protein 4 expression in ascending aorta tissue. The expression level of fatty-acid-binding protein 4 in epicardial adipose tissue was found to be significantly correlated with waist circumference in all subjects (r=.535, P<.05). Our data showed for the first time that human epicardial adipose and ascending aorta tissues express fatty-acid-binding protein 4 and that its level of expression in epicardial adipose tissues of metabolic syndrome patients is elevated. Increased fatty-acid-binding protein 4 gene expression in epicardial adipose tissues of metabolic syndrome patients led us think that fatty-acid-binding protein 4 might be an important factor in metabolic syndrome.

CYP21A2 gene mutations in congenital adrenal hyperplasia: genotype-phenotype correlation in Turkish children.

Background: Congenital adrenal hyperplasia (CAH) due 21−hydroxylase deficiency (21−OHD) is a common autosomal recessive disorder. It is caused by defects in the CYP21A2 gene. Objective: Our aim was to determine the frequency of common gene mutations and to evaluate genotype−phenotype correlations in Turkish 21−OHD patients. Methods: Molecular analysis of the CYP21A2 gene was performed for the detection of the eight most common point mutations [p.P30L, IVS2−13C>G (IVS−2), p.I172N, exon 6 mutation cluster (p.I236N, p.V237E, p.M239K), p.V281L, p.Q318X, p.R356W, 8−bp−deletion], of large deletion and conversion by southern blotting, allele specific semi−quantitative PCR/enzyme restriction method and sequencing, in 56 patients with 21−OHD, from 52 families. Results: Disease−causing mutations were identified in 77 out of 91 alleles (84.6%) of the patients. Mutations were found in 34 of 43 alleles (79.1%) in salt wasting (SW; n=26), 32 of 36 alleles (88.8%) in simple virilizing (SV; n=24) and 11 of 12 alleles (91.6%) in non−classical (NC; n=6) form of CAH. The most frequent mutations were IVS−2 (22.0%), large conversion (14.3%), p.I172N (9.9%) p.R356W (8.8%), and large deletion (6.6%). In the SW form, the most frequent genotypes were homozygous for IVS−2 (11.5%) and homozygous for large conversion of the gene (11.5%). In the SV form, the most frequent genotype was homozygous for IVS−2 (20%), followed by compound heterozygous for p.I172N/8−bp del (10%). Homozygous for p.V281L (16.7%) was most common in NC. In most cases there was good correlation between genotype and phenotype. In the SW and NC forms, genotypes of all the patients correlated with their phenotypes. Conclusions: This is the first comprehensive study on the molecular basis of CAH patients in the Turkish population. Based on these results, we propose a modified screening strategy to facilitate molecular testing of CAH patients in our population. Conflict of interest:None declared.

Growth Hormone/Insulin-Like Growth Factor-1 Axis as Related to Body Mass Index in Patients with Idiopathic Short Stature

Objective: Idiopathic short stature (ISS) is a heterogeneous disorder. An impairment of growth hormone (GH)/insulin-like growth factor 1 (IGF-1)/IGF-1 receptor (IGF-1 R) axis is postulated. To evaluate the somatotropic axis in relation to body mass index (BMI), serum IGF-1, IGF-binding protein-3 (IGFBP-3) and the expression of IGF-1 R genes in patients with ISS. Methods: Fifty-five ISS patients (24F/31M) aged 14.6±5.5 years (range 3.5-28.5 years) and 25 BMI- and pubertal stage-matched peers were enrolled in the study. The ISS patients underwent a four-day standard GH stimulation test to evaluate IGF-1 generation. mRNA expression of the IGF-1 R gene in peripheral blood leukocytes was evaluated. ISS patients and controls were compared with respect to anthropometric and laboratory data. The results were also analyzed after subdividing the two groups into low-normal [BMI standard deviation score (SDS) between -2 to -1)] and normal (BMI SDS between -1 to +1) BMI subgroups. Results: Basal serum IGF-1 concentrations were lower in ISS subjects compared to controls who had similar BMI SDS values (p=0.000). Subgroup analyses revealed that there were no significant differences between low-normal BMI ISS subjects and low-normal BMI controls with respect to serum IGF-1 and IGFBP-3 concentrations. However, in the normal BMI ISS subgroup, basal and stimulated IGF-1 levels were significantly lower than the basal values in their control counterparts (basal: p=0.000; stimulated: p=0.007). mRNA expression of IGF-1 R gene was not found to be significantly different in ISS subjects and controls. Conclusions: ISS patients were found to have lower IGF-1 concentrations than BMI-matched peers, a finding supporting presence of an impairment in the somatotropic axis. IGF-1 R expression does not seem to be impaired in ISS patients. ISS patients with low-normal BMI SDS also tend to display a relative IGF-1 resistance, whereas those with normal BMI SDS tend to be less GH-sensitive than healthy peers. Conflict of interest:None declared.

The role of mediastinal adipose tissue 11β-hydroxysteroid d ehydrogenase type 1 and glucocorticoid expression in the development of coronary atherosclerosis in obese patients with ischemic heart disease

BackgroundVisceral fat deposition and its associated atherogenic complications are mediated by glucocorticoids. Cardiac visceral fat comprises mediastinal adipose tissue (MAT) and epicardial adipose tissue (EAT), and MAT is a potential biomarker of risk for obese patients.AimOur objective was to evaluate the role of EAT and MAT 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) and glucocorticoid receptor (GCR) expression in comparison with subcutaneous adipose tissue (SAT) in the development of coronary atherosclerosis in obese patients with coronary artery disease (CAD), and to assess their correlations with CD68 and fatty acids from these tissues.Methods and resultsExpression of 11β-HSD-1 and GCR was measured by qRT-PCR in EAT, MAT and SAT of thirty-one obese patients undergoing coronary artery bypass grafting due to CAD (obese CAD group) and sixteen obese patients without CAD undergoing heart valve surgery (controls). 11β-HSD-1 and GCR expression in MAT were found to be significantly increased in the obese CAD group compared with controls (p < 0.05). In the obese CAD group, 11β-HSD-1 and GCR mRNA levels were strongly correlated in MAT. Stearidonic acid was significantly increased in EAT and MAT of the obese CAD group and arachidonic acid was significantly expressed in MAT of the obese male CAD group (p < 0.05).ConclusionsWe report for the first time the increased expression of 11β-HSD-1 and GCR in MAT compared with EAT and SAT, and also describe the interrelated effects of stearidonic acid, HOMA-IR, plasma cortisol and GCR mRNA levels, explaining 40.2% of the variance in 11β-HSD-1 mRNA levels in MAT of obese CAD patients. These findings support the hypothesis that MAT contributes locally to the development of coronary atherosclerosis via glucocorticoid action.

Mediastinal adipose tissue expresses a pathogenic profile of 11 β-hydroxysteroid dehydrogenase Type 1, glucocorticoid receptor, and CD68 in patients with coronary artery disease

OBJECTIVE Cardiac visceral fat is accepted to be a new marker for cardiometabolic risk due to its association with increased cardiovascular risk factors. This study aimed to compare the expression of 11 beta hydroxysteroid dehydrogenases (11β-HSD)-1, glucocorticoid receptor (GCR), and CD68 in mediastinal and subcutaneous adipose tissues (MAT, and SAT, respectively) and to assess their possible relationships with the development of coronary artery disease (CAD). METHODS AND RESULTS Expression of 11β-HSD-1, GCR, and CD68 mRNA levels were measured by quantitative real-time polymerase chain reaction in MAT and SAT tissues of 37 patients undergoing coronary artery bypass grafting due to CAD (CAD group) and 19 non-CAD patients (controls) undergoing heart valve surgery. 11β-HSD-1 in MAT and SAT and GCR expression in MAT and SAT were found to be significantly increased in CAD group when compared with controls (P<.05, respectively). In CAD group, 11β-HSD-1 mRNA levels were found to be significantly higher in MAT compared to SAT (P<.05). CD68 mRNA levels were significantly higher in MAT of CAD group compared to controls (P<.05). Immunohistochemical analyses demonstrated the presence of CD68+ cells and increased 11β-HSD-1 expression in MAT of CAD group compared to SAT. CONCLUSION The present study demonstrate that the mediastinal fat exhibits a pathogenic mRNA profile of 11β-HSD-1, GCR, and CD68. The identification of 11β-HSD-1 expression within the mediastinal fat, along with increased GCR expressions and the presence of CD68+ cells highlight that MAT potentially contributes to the pathogenesis of CAD.

Identification of a novel BRCA2 and CHEK2 A-C-G-C haplotype in Turkish patients affected with breast cancer.

BACKGROUND Many breast cancers are caused by certain rare and familial mutations in the high or moderate penetrance genes BRCA1, BRCA2 and CHEK2. The aim of this study was to examine the allele and genotype frequencies of seven mutations in BRCA1, BRCA2 and CHEK2 genes in breast cancer patients and to investigate their isolated and combined associations with breast cancer risk. METHODS We genotyped seven mutations in BRCA1, BRCA2 and CHEK2 genes and then analyzed single variations and haplotype associations in 106 breast cancer patients and 80 healthy controls. RESULTS We found significant associations in the analyses of CHEK2- 1100delC (p=0.001) and BRCA1-5382insC (p=0.021) mutations in breast cancer patients compared to controls. The highest risk was observed among breast cancer patients carrying both CHEK2-1100delC and BRCA2- Met784Val mutations (OR=0.093; 95%CI 0.021-0.423; p=0.001). We identified one previously undescribed BRCA2 and a CHEK2 four-marker haplotype of A-C-G-C which was overrepresented (?2=7.655; p=0.0057) in the patient group compared to controls. CONCLUSION In this study, we identified a previously undescribed BRCA2 and CHEK2 A-C-G-C haplotype in association with the breast cancer in our population. Our results further suggest that the CHEK2-1100delC mutation in combination with BRCA2-Met784Val may lead to an unexpected high risk which needs to be confirmed in larger cohorts in order to better understand their role in the development and prognosis of breast cancer.

OPN gene polymorphism (Ala250) and lower serum OPN levels are associated with urolithiasis

Abstract Osteopontin (OPN) is one of the urinary proteins with an important role in stone formation. Recently, OPN Ala250 (rs1126616) polymorphism and other single nucleotide polymorphisms (SNPs) have been studied to define their role in urolithiasis. This study was conducted to examine the impact of OPN Ala250 polymorphism on the risk of stone formation and their association with serum OPN levels. OPN Ala250 polymorphism was investigated in 127 urolithiasis patients and 92 healthy controls. Stones were analyzed for their chemical composition by using X-Ray diffraction method. Genomic DNA was isolated from peripheral blood leucocytes. The study groups were genotyped by PCR-RFLP and serum OPN levels were measured by ELISA. There was a significant difference between urolithiasis patients and controls concerning genotype and allele frequencies of OPN Ala250 (p < 0.05). Separate analysis by BMI greater or less than 25 kg/m2 showed that the presence of one mutant T-allele was more frequent in patients with higher BMI than patients with BMI less than 25 kg/m2 (p < 0.05). Serum OPN concentrations were two-fold higher in the control group compared to urolithiasis patients (p < 0.05). But the mean serum levels did not show any significant difference between OPN Ala250 genotypes in both groups. Moreover, we found an association between higher BMI and stone formation. Our findings suggest that OPN Ala250 polymorphism is associated with the correlation between weight gain and urolithiasis. However, the correlation between urolithiasis and obesity needs to be further studied in larger cohorts.

herg1b Expression as a Potential Specific Marker in Pediatric Acute Myeloid Leukemia Patients with HERG 897K/K Genotype

Human ether-a-go-go related gene (herg) encoding HERG K+ channel has been demonstrated in many previous studies with its association to cell cycle progression and growth in tumor cells. The upregulated expression of HERG K+ channels was determined in different tumor types. Furthermore, not only full-length transcript herg1 but also a truncated isoform herg1b was shown to be expressed in cancer cells. In this study, the expression levels of herg1 and herg1b and the impact of K897T mutation on their expressions were investigated in pediatric acute myeloid leukemia (pAML). Expression levels of herg1 and herg1b isoforms were analyzed by quantitative real time polymerase chain reaction (PCR) in pAML patients together with healthy donors, and their expressions were confirmed by western blotting. The 2690 A>C nucleotide variation in KCNH2 gene corresponding to K897T amino acid change was analyzed by PCR followed by restriction enzyme digestion. herg1b overexpression was observed in tumor cells compared to healthy controls (P = .0024). However, herg1 expression was higher in healthy control cells than tumor cells (P = .001). The prevalence of polymorphic allele 897T was 26% in our patient group and 897T carriers showed increased herg1b expression compared to wild-type allele carriers. Our results demonstrate the presence of the increased levels of herg1b expression in pAML. In addition, we report for the first time that, pAML subgroup with HERG 897K/K genotype compared to 897K/T and T/T genotypes express increased levels of herg1b. In conclusion, HERG 897K/K genotype with increased level of herg1b expression might well be a prognostic marker for pAML.

No Effect of the IGF-1 Gene rs35767 and rs17032362 Polymorphisms in the Etiology of Idiopathic Short Stature

Idiopathic short stature (ISS) refers to pathophysiologically wide and heterogeneous range of disorders, which are considered to involve defects in growth hormone (GH) insulin like growth factor-1 (IGF-1) axis. This study was designed to evaluate GH- IGF-1 axis and investigate IGF-1 gene polymorphisms in ISS.108 patients with a mean age of 11.7±3.6 years constituted the study group, while 108 age and gender matched children with normal stature constituted the control group. Serum IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3) levels and two polymorphisms in IGF-1 gene (rs35767, rs17032362) were investigated.While mean IGF-1 SDS value was lower in study group (p=0.002), no difference was detected between mean IGFBP-3 SDS values. The IGF-1 gene rs35767 polymorphism genotype distribution did not exhibit a statistical difference between study (7.1% wild type, 29.6% heterozygous, 63.3% homozygous) and control groups (3.8% wild type, 39.6% heterozygous, 56.6% homozygous). IGF-1 gene rs17032362 polymorphism genotype distribution was not significantly different either between study (94.8% wild type, 5.2% heterozygous, 0% homozygous) and control groups (97.2% wild type, 2.8% heterozygous, 0% homozygous). Comparing the cases with wild type, homozygous and heterozygous carriers for both polymorphisms with respect to height, weight, BMI, IGF-1 and IGFBP-3 SDS values, no significant difference was detected.IGF-1 SDS levels of patients with ISS were significantly lower compared to control group. There was no difference between IGFBP-3 SDS levels. No effect of IGF-1 gene rs35767 and rs17032362 polymorphisms on stature, IGF-1 and IGFBP-3 levels could be demonstrated.

1508 – Association study of the dio2 gene as a susceptibility candidate for schizophrenia in the turkish population; a case-control study

Introduction Schizophrenia (SCH) is one of the major and potentially severe mental illness that is characterized by both genetic and clinical heterogeneity. Thyroid hormone plays an important role in the development of the brain and nervous system both in the basic process of neurogenesis and of terminal brain differentiation. Type II deiodinase (DIO2) enzyme which has a critical role on thyroid hormone metabolism to convert pro-hormone thyroxine (T4) to the active hormone triiodothyronine (T3). Recently, DIO2 gene variations have been identified in association with mental disorders. Methods To investigate the potential genetic contribution of the DIO2 gene to SCH, we studied DIO2 Thr92Ala (rs225014) and ORFa-Gly3Asp (rs12885300) polymorphisms in a Turkish cohort of 290 unrelated SCH patients and 198 healthy controls. All subjects were genotyped by Taqman SNP genotyping assays. Results Single marker analysis showed a positive association of SCH and rs225014. Particularly, Thr92Ala genotype frequency was significantly higher in patients with SCH than controls (p=0.045) and in male patients with SCH, both allele and genotype frequencies were significantly higher compared to male controls (p=0.03). Allele and genotype frequencies of ORFa- Gly3Asp polymorphism were no different within the study group. Conclusion These data show a potential role of DIO2 as a candidate gene for susceptibility to SCH and provide a strong evidence for a role of the DIO2 Thr92Ala allele and genotype in the etiopathogenesis of SCH with sexual difference.