Erkan Yurtcu

Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-γ gene in women with polycystic ovary syndrome

Aim. The present study was designed to examine the relationship between Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-γ gene (PPAR-γ) and clinical and hormonal characteristics in women with polycystic ovary syndrome (PCOS). Materials and methods. One hundred patients with PCOS and 100 healthy subjects were included in the study. Serum levels of sex steroids were measured. Insulin resistance was evaluated by homeostasis model assessment (HOMA). The responses of glucose and insulin to an oral glucose tolerance test were analyzed by calculating the respective area under the curve (AUC) by the trapezoidal method. We used the restriction fragment length polymorphism technique and polymerase chain reaction to examine Pro12Ala polymorphism in exon 2 of PPAR-γ. Results. Pro12Ala polymorphism of PPAR-γ was significantly elevated in control subjects (22%) compared with PCOS subjects (15%). All of the Pro12Ala polymorphisms of PPAR-γ were heterozygous. When PCOS subjects with the Pro allele and the Ala allele of PPAR-γ were compared, the latter had lower free testosterone, androstenedione, dehydroepiandrosterone sulfate, insulin and C-peptide levels, as well as lower luteinizing hormone/follicle-stimulating hormone ratio, HOMA insulin resistance index, AUCinsulin, Ferriman–Gallwey score, acne, body mass index and waist-to-hip ratio. Conclusion. We suggest that Pro12Ala polymorphism of the PPAR-γ gene may be a modifier of insulin resistance in women with PCOS.

PON1 55 and 192 Gene Polymorphisms in Type 2 Diabetes Mellitus Patients in a Turkish Population

Diabetes mellitus is a multifactorial metabolic disease, caused by the complete or relative absence of insulin hormone, which results in the deterioration of carbohydrate, protein, and lipid metabolism. The PON1 55 and 192 polymorphisms have been reported to be associated with type 2 diabetes and its complications. In this study, the involvement of the PON1 55 and 192 polymorphisms and paraoxonase enzyme activity in diabetic complications was assessed. The MM and QQ genotypes were the most frequent in complications of type 2 diabetes in both of the polymorphisms. PON enzyme activity was lower in the type 2 diabetes group with respect to the control group. Regarding both genotypes and enzyme activity, correlations were found between the PON1 55 and 192 genotypes and diabetic complications. This study thus helps to outline a genotype–phenotype relation for the PON1 gene in a Turkish population.

Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma gene in first-degree relatives of subjects with polycystic ovary syndrome.

Aim. This study was designed to examine the relationship between the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-γ (PPAR-γ) gene and insulin resistance (IR) in first-degree relatives of subjects with polycystic ovary syndrome (PCOS). Materials and methods. One hundred and twenty family members of 55 patients with PCOS and 80 unrelated healthy control subjects without a family history of diabetes or PCOS were studied. IR was assessed by homeostatic model assessment (HOMA-IR) and area under the curve (AUC) for insulin during an oral glucose tolerance test in subjects with normal glucose tolerance and controls. Genetic analysis of the PPAR-γ gene Pro12Ala polymorphism was performed by restriction fragment length polymorphism. Results. Fasting insulin, HOMA-IR and AUC insulin were significantly higher in first-degree relatives of PCOS subjects than in controls. A significantly different allele distribution of the Pro12Ala polymorphism of PPAR-γ was observed between the two groups, with the frequency of the variant Ala isoform being significantly reduced in the first-degree relatives of PCOS subjects (10.8%, 13 subjects) compared with the control group (22.5%, 18 subjects). All Pro12Ala polymorphisms of the PPAR-γ gene were heterozygous. Compared with first-degree relatives of PCOS subjects with the Pro12Pro polymorphism of PPAR-γ, first-degree relatives of PCOS subjects with the Pro12Ala polymorphism had low fasting insulin, HOMA-IR and AUC insulin levels. The combined prevalence rate for impaired glucose tolerance, impaired fasting glucose and diabetes was 40% (16 subjects) in mothers and 52% (20 subjects) in fathers of PCOS women. Conclusion. Our findings suggest that Pro12Ala PPAR-γ gene polymorphism may be protective against IR and might prevent the development of diabetes mellitus in the first-degree relatives of subjects with PCOS.

Protective effect of ginkgo biloba against gossypol-induced apoptosis in human lymphocytes.

Ginkgo biloba (EGb 761) is a well‐defined plant extract that directly scavenges hydroxyl radicals. It is a potent antioxidant that inhibits apoptosis in cultured cells and is effective in treating mild‐to‐moderate dementia in Alzheimer patients. Apoptosis is an active process of cell destruction and it plays an important role in pathological processes. The aim of this study is to investigate the anti‐apoptotic effect of EGb 761 in gossypol‐treated human lymphocytes. Pretreatment of lymphocytes with 10 μg/ml EGb 761 for 30 min or 1 h decreased the percentage of apoptosis to 17.5% and 20%, respectively. EGb 761 treatment (25–150 μg/ml) decreased the level of apoptosis to a plateau between 8 and 10% of the control values. We conclude that EGb 761 reduces gossypol‐induced apoptosis in human lymphocytes.

Frequency of adiponectin gene polymorphisms in polycystic ovary syndrome and the association with serum adiponectin, androgen levels, insulin resistance and clinical parameters

Aim. Although the association between adiponectin gene polymorphisms and insulin resistance has been investigated in many studies, there are only a few studies, which have investigated adiponectin gene polymorphisms in patients with polycystic ovary syndrome (PCOS). The objectives of this study were to determine the frequency of T45G polymorphisms localised in exon 2 of the adiponectin gene in a Turkish population with PCOS and to determine the association of T45G polymorphisms with insulin resistance and serum adiponectin levels in PCOS. Materials and methods. Ninety-six patients with PCOS and 93 healthy control subjects were included in the study. Insulin resistance was estimated via HOMA-IR. Serum adiponectin levels were measured by ELISA. For determination of adiponectin gene polymorphisms, PCR was performed with appropriate primers after genomic DNA was obtained from the peripheral blood of the patients and control subjects. Results. Adiponectin levels were low in patients with PCOS than control subjects. There was no significant statistical difference between the PCOS and control groups with respect to the frequency of polymorphisms and the genotype distribution. Adiponectin gene polymorphisms were not associated with the anthropometric parameters, hyperandrogenism and adiponectin levels in PCOS. However, the fasting insulin level and insulin resistance were significantly higher and more frequent, respectively, in the polymorphic group compared to the other genotypes among patients with PCOS. Conclusion. The risk of PCOS, hyperandrogenism in patients with PCOS and low serum adiponectin levels cannot be directly attributed to T45G adiponectin gene polymorphisms in exon 2, rather these polymorphisms may be associated with insulin resistance and hyperinsulinemia in PCOS.

Detecting methylation patterns of p16, MGMT, DAPK and E-cadherin genes in multiple myeloma patients.

Multiple myeloma (MM) is a B‐cell neoplasia characterized by the clonal proliferation of plasma cells. Besides known genetic abnormalities, epigenetic changes are also known to effect MM pathogenesis. DNA methylation is an epigenetic mechanism that silences genes by adding methyl groups to cytosine‐guanine dinucleotides at the promoter regions. In this study, the methylation status of four genes; p16, O6‐methyl guanine DNA methyl transferase (MGMT), death‐associated protein kinase (DAPK) and E‐cadherin (ECAD); at the time of diagnosis was investigated using methylation‐specific polymerase chain reaction (MS‐PCR). In the 20 cases studied; methylation of the promoter regions of p16, MGMT, DAPK and ECAD genes was detected in 10%, 40%, 10% and 45% of the cases, respectively. In 65% (13/20) of cases, at least one of the genes studied had promoter methylation; while 35% of cases (7/20) had methylated promoters of more than one gene. There was a significant correlation between promoter hypermethylation of MGMT and the presence of extramedullary involvement; but for the other genes no correlation was found regarding disease properties like age, disease stage, clinical course and the presence of lytic bone lesions. Determining the methylation profiles of genes in MM, could lead to a new understanding of the disease pathogenesis and guide the assessment of treatment options.

Matrix metalloproteinase-9 promoter gene polymorphism (-1562C>T) in nasal polyposis.

Background Expression of matrix metalloproteinase (MMP)-9 increases in nasal polyp tissues. However, the impact of MMP-9 genotypes on the development of nasal polyposis (NP) is unknown. The aim of this study was to examine a potential association of MMP-9 promoter gene polymorphism with the development of NP. Methods A prospective and case–control study was performed on 93 patients with NP and 115 controls without sinonasal disease. Genotypes of MMP-9 (–1562C>T) were identified by restriction fragment length polymorphism analyses after polymerase chain reaction. Results The frequency of – 1562CT genotype of MMP-9 was significantly high in NP patients with aspirin-induced asthma (p = 0.014). Distribution of T allele was significantly high in NP patients with aspirin-induced asthma (p = 0.013). MMP-9 genotypes were not associated with gender or the presence of atopy. Conclusion In this study, MMP-9 – 1562CT genotype was associated with susceptibility to NP in aspirin-induced asthmatic patients. Because this report is a population-based study, further research should be performed on larger study subjects to reveal the precise role of MMP-9 promoter gene polymorphism in the development of NP.

Apoptotic effect of gossypol on human lymphocytes.

The overall objective of this study was to determine the effect of gossypol on human lymphocytes. Blood samples were taken from healthy donors and lymphocytes were cultured with various concentrations of gossypol (25–150 μM). The percentage of apoptotic cells was determined by assessing DNA fragmentation by agarose gel electrophoresis; morphological features of apoptosis were assessed by light microscopy. The concentrations of gossypol required to induce apoptosis in human lymphocytes without causing necrosis through cytotoxic effects were between 25–50 μM.

beta-Adrenoreceptor antagonists reduce cancer cell proliferation, invasion, and migration

Abstract Context: Propranolol, atenolol, and ICI118,551 are non-selective β-adrenergic receptor (AR), β1-AR, and β2-AR antagonists, respectively. Objective: We investigated the efficacy of propranolol, atenolol, and ICI118,551 on proliferation, migration, and invasion of non-stimulated breast (MCF7), colon (HT-29), and hepatocellular (HepG2) cancer cells. Materials and methods: β-AR expression profiling of cells was performed by real time PCR. Cell proliferation was determined by MTT. Boyden chamber and scratch assays were performed to evaluate invasion and migration. Results and discussion: All cell lines expressed β-ARs. ICI118,551 was the most cytotoxic, whereas atenolol was the least effective β-AR antagonist for 24, 48, and 72 h. Cell invasion was inhibited by ICI118,551 (45, 46, and 50% for MCF7, HT29, and HepG2, respectively) and propranolol (72, 65, and 90% for MCF7, HT29, and HepG2, respectively). Propranolol, atenolol, and ICI118,551 reduced migration of MCF7, HT-29, and HepG2 cells to varying extents depending on the application concentration and duration. Propranolol and atenolol reduced migration of MCF7 and HT-29 in a concentration-dependent manner, whereas migration of these cells decreased after 48 and 72 h of ICI118,551 applications. Conclusion: Beta2-AR antagonist seemed to be the most cytotoxic β-blocker on non-stimulated cancer cells. Propranolol and ICI118,551 were more effective than atenolol in inhibiting invasion and migration of non-stimulated MCF7 and HT-29 cells; ICI118,551 being the most potent. Concordantly, β2-selective blockage seemed to be more effective for non-stimulated cells. Effect of the selective β-AR antagonists showed variation depending on the concentration, incubation time, and histological origin of cells.

Calpain 10 gene single-nucleotide 44 polymorphism may have an influence on clinical and metabolic features in patients with polycystic ovary syndrome

Aim: This study was designed in order to examine the relationship between Calpain 10 [single-nucleotide polymorphism (SNP) 19,43,44,63] gene polymorphisms and clinical and hormonal characteristics in women with polycystic ovary syndrome (PCOS). Materials and methods: One hundred and seven patients with PCOS and 114 healthy subjects were included in this study. Serum levels of sex steroids were measured for each individual. Insulin resistance (IR) was evaluated by the homeostasis model assessment (HOMA) and quantitative insulin-sensitivity check index (QUICKI) methods. Insulin and glucose responses to the oral glucose tolerance test (OGTT) were analyzed by calculating the areas under the curve for insulin (AUCI) and glucose by the trapezoidal methods. We used PCR and restriction fragment length polymorphism technique to examine Calpain 10 SNP 19, 43, 44, and 63 polymorphisms. Results: Allele distribution of Calpain 10 SNP 44 gene polymorphism was observed as significantly different between the groups. Calpain 10 SNP 44 TC genotype was found to be increased in PCOS subjects (69.15%) compared to the control subjects (50%). However, when compared to control subjects, patients with PCOS had similar Calpain 10 SNP 19, Calpain 10 SNP 43, and SNP 63 gene polymorphisms. When compared with normal Calpain 10 gene SNP 44 allele in PCOS subjects, subjects with PCOS having Calpain 10 gene SNP 44 allele polymorphism had higher free testosterone, androstenedione, DHEA-S, and fasting insulin levels. Also, PCOS women with Calpain 10 gene SNP 44 allele polymorphism had high Ferriman-Gallwey (F-G) score, acne, prevalence of menstrual disturbances, waist-hip ratio, HOMA-IR, AUCI levels and low QUICKI levels. Conclusion: The findings show that Calpain 10 gene SNP 44 allele polymorphism may have a role in PCOS pathogenesis. However, larger-scale studies are needed in this field.