Zeliha Kayaalti

Arg753Gln polymorphism of the human Toll-like receptor 2 gene from infection to disease in pediatric tuberculosis

The aim of this study is to examine the occurrence of the Arg753Gln polymorphism of the Toll-like receptor 2 (TLR2) gene in Turkish children with pulmonary and/or extrapulmonary tuberculosis (TB) disease compared with that in healthy children with latent TB infection (LTBI) and to assess the risk of progression from LTBI to active TB disease in children. The Arg753Gln polymorphism of the TLR2 gene was studied in 198 TB patients compared with 200 ethnically and age-matched children with LTBI. The culture confirmed TB patients were more frequently Arg753Gln heterozygous [odds ratio (OR) 5.05, 95% confidence interval (95% CI) 2.61-9.76, p = 0.00], and Gln allele frequency was significantly higher in the patient group (13.86% vs 3.5%, OR 4.40, 95% CI 2.34-8.30, p = 0.00). We also showed that the frequencies of the heterozygous Arg753Gln genotype and the Gln allele were significantly higher in patients with pulmonary TB alone and in patients with definitive pulmonary plus extrapulmonary TB than in children with LTBI. Our data suggest that the Arg753Gln polymorphism of the TLR-2 gene influences the speed of progression from infection to TB disease in children. Further investigations are needed to clarify whether this polymorphism has a strong impact on susceptibility to TB in children.

Effect of metallothionein core promoter region polymorphism on cadmium, zinc and copper levels in autopsy kidney tissues from a Turkish population.

Metallothioneins (MTs) are metal-binding, low molecular weight proteins and are involved in pathophysiological processes like metabolism of essential metals, metal ion homeostasis and detoxification of heavy metals. Metallothionein expression is induced by various heavy metals especially cadmium, mercury and zinc; MTs suppress toxicity of heavy metals by binding themselves to these metals. The aim of this study was to investigate the association between the -5 A/G metallothionein 2A (MT2A) single nucleotide polymorphism (SNP) and Cd, Zn and Cu levels in the renal cortex from autopsy cases. MT2A core promoter region -5 A/G SNP was analyzed by PCR-RFLP method using 114 autopsy kidney tissues and the genotype frequencies of this polymorphism were found as 87.7% homozygote typical (AA), 11.4% heterozygote (AG) and 0.9% homozygote atypical (GG). In order to assess the Cd, Zn and Cu levels in the same autopsy kidney tissues, a dual atomic absorption spectrophotometer system was used and the average levels of Cd, Zn and Cu were measured as 95.54+/-65.58 microg/g, 181.20+/-87.72 microg/g and 17.14+/-16.28 microg/g, respectively. As a result, no statistical association was found between the -5 A/G SNP in the MT2A gene and the Zn and Cu levels in the renal cortex (p>0.05), but considerably high accumulation of Cd was monitored for individuals having AG (151.24+/-60.21 microg/g) and GG genotypes (153.09 microg/g) compared with individuals having AA genotype (87.72+/-62.98 microg/g) (p<0.05). These results show that the core promoter region polymorphism of metallothionein 2A increases the accumulation of Cd in human renal cortex.

Relationship between Toll-Like Receptor 8 Gene Polymorphisms and Pediatric Pulmonary Tuberculosis

Objectives: Genetic variants in Toll-like receptors (TLRs) are considered a potential indicator for host susceptibility to and outcome of several infectious diseases including tuberculosis. The aim of this study was to determine whether −129 C/G and Met1Val polymorphisms of TLR8 were associated with pediatric pulmonary tuberculosis in Turkish population. Methods: The −129 C/G and Met1Val polymorphisms were studied in 124 children with pulmonary tuberculosis compared to 150 age-matched healthy control subjects. Results: We did not identify any statistically significant differences between the patients with TB and control groups with regard to the frequency of genotypes GG or G/(−), CG, and CC or C/(−); and alleles G and C at rs3764879 (p > 0.05). We found a strong association with genotype A/(−) at rs3764880 with susceptibility to pulmonary TB in males (OR 2.87, 95%CI 1.38–5.98, p = 0.007). Conclusions: Our results provide evidence, for the first time, of a role for the TLR8 gene in susceptibility to pulmonary TB in male children. Additional research to verify our results are necessary. Tuberculosis in children presents particularly difficult challenges, but research priorities and advances in pediatric tuberculosis could provide wider insights and opportunities for tuberculosis control.

Distribution of ADH1B, ALDH2, CYP2E1*6 and CYP2E1*7B genotypes in Turkish population

The most well-known metabolic pathways from ethanol to acetaldehyde include alcohol dehydrogenase (ADH) and the microsomal ethanol oxidizing system that involves cytochrome P450 2E1 (CYP2E1). Acetaldehyde is further oxidized to acetate by aldehyde dehydrogenase (ALDH). The genetic variation of ADH1B, ALDH2, and CYP2E1 is different among racial populations and cause difference in elimination rates of alcohol. The aim of this study was to determine the polymorphisms of ADH1B (rs1229984; Arg47His), ALDH2 (rs671; Glu487Lys), CYP2E1*6 (rs6413432; T7632A), and CYP2E1*7B (rs6413420; G-71T) in unrelated healthy Turkish population and compare it with other populations. ADH1B and ALDH2 polymorphisms were analyzed with an allele-specific polymerase chain reaction (PCR) assay, and CYP2E1*6 and CYP2E1*7B polymorphisms were genotyped by PCR-restriction fragment length polymorphism method. ADH1B polymorphism analysis yielded the genotype distribution as 83.9% ADH1B*1/1 and 16.1% ADH1B*1/2, and no individuals with ALDH2*1/2 and ALDH2*2/2 genotypes were found in Turkish population. The genotype frequencies for CYP2E1*6 polymorphism were found as 85.3% for homozygote common, 14.1% for heterozygote, and 0.6% for homozygote uncommon. For CYP2E1*7B polymorphism, the genotype frequencies were determined to be 86.5% G/G, 13.5% for G/T; however, no individuals with homozygote uncommon genotype were detected. According to our study results, the genotype distributions of ADH1B, ALDH2, CYP2E1*6, and CYP2E1*7B in Turkish population were similar compared with Caucasian and some European populations, whereas differed significantly from East Asian populations. This study may be useful in epidemiological studies of the influence of ADH1B, ALDH2, CYP2E1*6, and CYP2E1*7B polymorphisms on diseases, including several types of cancer related to alcohol consumption and alcohol dependence.

The effects of metallothionein 2A polymorphism on placental cadmium accumulation: Is metallothionein a modifiying factor in transfer of micronutrients to the fetus?

Metallothionein affects the metabolism, transport and storage of micronutrients such as zinc, copper and iron, and the detoxification of heavy metals, especially cadmium. Cd is a common, highly toxic environmental pollutant that accumulates in human placenta, elevated concentrations of which are associated with impaired zinc transfer to the fetus. This prospective study investigated the effects of metallothionein 2A (MT2A) −5 A/G single nucleotide polymorphism on the accumulation of Cd in human placenta and micronutrient transfer to the fetus in 95 pregnant women and their newborns. Venous blood from the mother was collected to investigate Cd, Zn, Cu, Fe levels and MT2A polymorphism. Cord blood from the neonate and placenta was collected for metal levels. MT2A polymorphism was determined by the standard PCR‐restriction fragment length polymorphism technique. Metal levels were analyzed by Atomic Absorption Spectrometry (AAS). Maternal blood Cd levels were statistically higher for mothers with a heterozygote genotype compared with a homozygote genotype (P < 0.05). In contrast, placental Cd levels were significantly higher in mothers with a homozygote rather than a heterozygote genotype (P < 0.05). No difference existed in cord blood Cd, Zn and Cu levels. However, cord blood Fe levels of newborns with heterozygote genotype mothers were higher than in others. Placental Cd levels of heterozygote genotype mothers were negatively associated with Zn in cord blood. Cd exposure at environmental levels may be associated with alteration of the umbilical cord micronutrient levels for newborns with mothers of a heterozygote genotype. Copyright

Distributions of interleukin-6 (IL-6) promoter and metallothionein 2A (MT2A) core promoter region gene polymorphisms and their associations with aging in Turkish population

Aging is determined as the product of an interaction among genetic, environmental and lifestyle factors. As interleukin-6 (IL-6) and metallothioneins (MTs) are related to inflammation and oxidative stress response, their genes are appropriate candidate for aging, age related diseases and infections. The aim of this study was to investigate the association between the IL-6 -174 G/C promoter region and MT2A -5 A/G core promoter region single nucleotide polymorphisms (SNPs) with longevity in Turkish population. Blood samples were collected from 354 individuals between 18 and 95 years of age. Individuals were classified into four groups according to their ages as 20-40, 41-60, 61-80, >80. IL-6 and MT2A polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Mean ages of individuals with IL-6 -74 C- carriers and C+ carriers were 49.82±20.45 years and 59.82±16.82 years, respectively. For the MT2A polymorphism, mean ages were estimated as 56.18±19.50 years for G- carriers and 47.59±13.45 years for G+ carriers. As a result, when the IL-6 and MT2A polymorphisms were compared with the mean ages and age groups, statistically significant associations were found (p<0.001 and p<0.05, respectively). In conclusion, these data support that the IL-6 -174 C+ carriers and MT2A -5 G- carriers may be more advantageous for longevity.

Polymorphism in the p2x7 gene increases susceptibility to extrapulmonary tuberculosis in Turkish children.

The P2X7 gene polymorphisms have been linked to increased risk for pulmonary and extrapulmonary tuberculosis in some populations. In this study, the genotype and allelic frequencies 1513A→C variant within the P2X7 gene was significantly higher than in the healthy controls (P = 0.035, P = 0.041). This is the first study demonstrating that the 1513A→C polymorphism is associated with extrapulmonary tuberculosis in children.

Evaluation of the effect of divalent metal transporter 1 gene polymorphism on blood iron, lead and cadmium levels

Divalent metal transporter 1 (DMT1), a member of the proton-coupled metal ion transporter family, mediates transport of ferrous iron from the lumen of the intestine into the enterocyte and export of iron from endocytic vesicles. It has an affinity not only for iron but also for other divalent cations including manganese, cobalt, nickel, cadmium, lead, copper, and zinc. DMT1 is encoded by the SLC11a2 gene that is located on chromosome 12q13 in humans and express four major mammalian isoforms (1A/+IRE, 1A/-IRE, 2/+IRE and 2/-IRE). Mutations or polymorphisms of DMT1 gene may have an impact on human health by disturbing metal trafficking. To study the possible association of DMT1 gene with the blood levels of some divalent cations such as iron, lead and cadmium, a single nucleotide polymorphism (SNP) (IVS4+44C/A) in DMT1 gene was investigated in 486 unrelated and healthy individuals in a Turkish population by method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The genotype frequencies were found as 49.8% homozygote typical (CC), 38.3% heterozygote (CA) and 11.9% homozygote atypical (AA). Metal levels were analyzed by dual atomic absorption spectrometer system and the average levels of iron, lead and cadmium in the blood samples were 446.01 ± 81.87 ppm, 35.59 ± 17.72 ppb and 1.25 ± 0.87 ppb, respectively. Individuals with the CC genotype had higher blood iron, lead and cadmium levels than those with AA and CA genotypes. Highly statistically significant associations were detected between IVS4+44 C/A polymorphism in the DMT1 gene and iron and lead levels (p=0.001 and p=0.036, respectively), but no association was found with cadmium level (p=0.344). This study suggested that DMT1 IVS4+44 C/A polymorphism is associated with inter-individual variations in blood iron, lead and cadmium levels.

Importance of NOD2/CARD15 gene variants for susceptibility to and outcome of sepsis in Turkish children

Objective: Severe sepsis remains a leading cause of morbidity and mortality in children. Given the link to pathogenesis, polymorphisms in genes involved in infection and inflammation may influence the outcomes in patients with sepsis and septic shock. The role of mutations within the innate immunity receptor NOD2/CARD15 has recently been demonstrated as a risk factor for bacteremia and mortality in adult patients with sepsis. The aim of this study was to evaluate the role of mutations of the NOD2/CARD15 gene in pediatric patients with sepsis. Design: Prospective cohort study. Setting: A tertiary care, ten-bed, pediatric intensive care unit. Patients: One hundred twenty-eight patients with sepsis admitted to the pediatric intensive care unit and healthy control group were included. Interventions: Venous blood from the children with sepsis and healthy controls was collected to investigate common polymorphisms (Arg702Trp, Gly908Arg, Leu1007fsincC) within the NOD2/CARD15 gene. Standard polymerase chain reaction restriction fragment length polymorphism technique was used to determine NOD2/CARD15 gene polymorphism. Measurement and Main Results: R702W, G908R, and Leu1007fsinsC variants in the NOD2/CARD15 gene were determined as significant risk factors associated with susceptibility to sepsis (p = .025, p = .031, p = .014, respectively). Sepsis-related mortality was increased in children carrying the Leu1007fsinsC variant (p = .041). Conclusions: The present article is the first report of clinical implications of NOD2/CARD15 gene variants in children with sepsis. Our findings suggest that common polymorphisms in the NOD2/CARD15 gene may play a major role in susceptibility to sepsis and the outcome of sepsis in children.

Association of cadmium but not arsenic levels in lung cancer tumor tissue with smoking, histopathological type and stage.

BACKGROUND To evaluate association of lung cancer with arsenic and cadmium levels measured in tumor tissue. MATERIALS AND METHODS Ninety-five patients with lung cancer tumor tissue obtained surgically were included in this study. Arsenic and cadmium levels were measured and levels of metals were compared among types of lung cancer and with reference to patient data. RESULTS The histopathologic diagnoses of the 95 cases were SCC, 49, adenocarcinoma, 28, large cell, 11 and SCLC, 1. Mean tumor arsenic and cadmium levels were 149.3±129.1μg/kg and 276.3±219.3μg/kg, respectively. Cadmium levels were significantly associated with smoking (p=0.02), histopathologic type (p=0.005), and TNM staging (r=0.325; p=0.001), although arsenic was not related to any parameter (p>0.05). There was no relation between metal levels and mortality (p>0.05). CONCLUSIONS We found a significant association between tumor cadmium levels of patients with lung cancer and smoking, histopathologic type and staging, although there was no relation with arsenic levels.