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ABSTRACT: The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) catalyzes the conversion of the hormonally inactive cortisone to active cortisol, thus facilitating glucocorticoid receptor activation in target tissues. Increased expression of 11beta-HSD1 in adipose tissue has been associated with obesity and insulin resistance. In this study, we investigated the association of two 11beta-HSD1 gene (HSD11B1) polymorphisms with the metabolic syndrome (MetS) and its characteristics in the Bosnian population.
The study included 86 participants: 43 patients diagnosed with MetS and 43 healthy controls. Subjects were genotyped for two HSD11B1 gene polymorphisms: rs846910: G > A and rs45487298: insA, by the high resolution melting curve analysis. Genotype distribution and an influence of genotypes on clinical and biochemical parameters were assessed.
There was no significant difference in the mutated allele frequencies for the two HSD11B1 gene polymorphisms between MetS patients and controls. In MetS patients, no significant associations between disease-associated traits and rs45487298: insA were found. Regarding rs846910: G > Avariant, heterozygous patients (G/A) had significantly lower systolic (P = 0.017) and diastolic blood pressure (P = 0.015), lower HOMA-IR index (P = 0.011) and higher LDL-cholesterol levels (P = 0.049), compared to the wild-type homozygotes. In the control group, rs45487298: insA polymorphism was associated with lower fasting plasma insulin levels (P = 0.041), lower homeostasis model assessment insulin resistance (HOMA-IR) index (P = 0.041) and lower diastolic blood pressure (P = 0.048). Significant differences between rs846910: G > A genotypes in controls were not detected. Haplotype analysis confirmed the association of rs45487298: insA with markers of insulin resistance in the control subjects. CONDUSIONS: Our results indicate that a common rs45487298: insA polymorphism in HSD1181 gene may have a protective effect against insulin resistance.
Biochemia Medica 01/2012; 22(1):76-85. · 1.34 Impact Factor
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ABSTRACT: In a state of caloric excess, adipose tissue plays an essential role by storing lipids. Its expandability determines the onset of metabolic syndrome (central obesity, dyslipidemia, glucose intolerance and hypertension). When the adipocyte endoplasmic reticulum is no longer capable of processing the excess nutrients, the so-called "endoplasmic reticulum stress" develops. This triggers efflux of free fatty acids from adipocytes into the circulation and causes triglyceride overload in skeletal muscle, liver and pancreas. Adipose tissue hypoxia then develops, due to the failure of vasculature to expand with adipocyte hypertrophy. Increased catabolism in mitochondria leads there to oxidative stress. Both phenomena cause deranged adipokine secretion and low-grade inflammation. Inflammatory cytokines, reactive oxygen species and ectopic lipid deposition are the main mediators of insulin resistance and vascular impairment, which both lead finally to diabetes type 2 and cardiovascular disease. Recently, fibrosis of adipose tissue was also demonstrated in obesity, contributing to the interplay of deleterious factors forcing inflammation. The present paper reviews recent evidence for adipose tissue dysfunction, trying to define causes and consequences. In conclusion, insulin resistance and associated complications originate from excess lipids, which cannot be stored without limit in adipose tissue, thus affecting its integrity and adipokine secretion.
Clinical Chemistry and Laboratory Medicine 09/2011; 49(12):1925-35. · 2.15 Impact Factor
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Sabina Semiz,
Tanja Dujic,
Barbara Ostanek,
Zelija Velija-Asimi,
Besim Prnjavorac,
Tamer Bego,
Maja Malenica, Barbara Mlinar,
Becir Heljic,
Janja Marc,
Adlija Causevic
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ABSTRACT: N-acetyltransferase 2 (NAT2) is a drug-metabolizing enzyme, which is genetically variable in human populations. Polymorphisms in the NAT2 gene have been associated with drug efficacy and toxicity as well as disease susceptibility. Recently, an association of NAT2 gene variation with risk of type 2 diabetes mellitus (T2DM) has been suggested. This is the first study performed in a population from Bosnia and Herzegovina (BH) in which the frequency of two common NAT2 polymorphisms, 341T>C (NAT2*5) and 590G>A (NAT2*6) was determined in diabetic patients.
The frequency of the NAT2*5 (341T>C) and NAT2*6 (590G>A) polymorphisms was analyzed by employing TaqMan SNP Genotyping Assays (Applied Biosystems) in a group of 63 patients with T2DM and 79 nondiabetic subjects.
Our data demonstrated that the frequencies of NAT2*5 (341T>C) and NAT2*6 (590G>A) polymorphisms in BH population were in line with the Caucasians genotype data. The NAT2*5 and NAT2*6 alleles were in high linkage disequilibrium (D' = 0.969). Strinkingly, there was a significant difference in genotype frequencies for NAT2*5 (p <0.05) and NAT2*6 (p <0.001) polymorphisms between diabetic and nondiabetic subjects. NAT2*5 polymorphism was associated with 2.4-fold increased risk for developing T2DM (adjusted OR = 2.40, 95% CI = 1.10-5.25, p = 0.028). On the contrary, NAT2*6 variant significantly decreased by 5-fold susceptibility to the disease (adjusted OR = 0.20, 95% CI = 0.09-0.43, p <0.001).
Our data demonstrated that NAT2 genetic variation appeared to be an important risk factor in development of T2DM.
Archives of medical research 05/2011; 42(4):311-7. · 1.88 Impact Factor
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ABSTRACT: Polycystic ovary syndrome (PCOS) is characterized by insulin resistance (IR) and central obesity. The impact of adipose tissue cortisol reactivation by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) on markers of obesity and IR was assessed in PCOS patients. Eighty-five PCOS patients and 43 controls were enrolled for subcutaneous adipose tissue biopsy; 25/85 patients and 29/43 controls underwent also visceral adipose tissue biopsy. HSD11B1 gene expression and expression of lipid metabolism genes were measured in subcutaneous and visceral adipose tissues. Anthropometric and biochemical markers of IR and PCOS were also assessed. HSD11B1 expression in visceral and subcutaneous adipose tissue was increased in PCOS patients compared to controls (p<0.05). After BMI adjustment, the difference was no longer significant. In PCOS patients, visceral HSD11B1 expression correlated positively with waist circumference (p=0.001), BMI (p=0.002), plasma insulin (p<0.05), systolic blood pressure (p=0.003), and lipoprotein lipase (LPL), hormone-sensitive lipase (LIPE) and peroxisome-proliferator activated receptor γ gene expression. Subcutaneous HSD11B1 expression correlated positively with BMI, waist circumference (p<0.001 for both) and HOMA-IR (p=0.003), and negatively with LPL, LIPE, adiponectin and glucose transporter GLUT4 gene expression. HSD11B1 expression in both depots showed a negative correlation with plasma HDL-cholesterol (p<0.03) and a positive one with C-reactive protein (p<0.001). In multiple regression analysis, HSD11B1 expression in visceral adipose tissue was most prominently associated with waist circumference, and that in subcutaneous adipose tissue with BMI (p<0.001 for both). Our results show that PCOS is not associated with increased HSD11B1 expression once adiposity is controlled for. Increased expression of this gene correlates with markers of adiposity and predicts IR and an unfavorable metabolic profile, independently of PCOS.
The Journal of steroid biochemistry and molecular biology 02/2011; 123(3-5):127-32. · 2.66 Impact Factor
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ABSTRACT: Lipin 1 is a recently discovered multifunctional protein involved in the metabolism of lipids, while PPARgamma is involved in adipocyte differentiation, and regulation of lipid metabolism. Up to now, LPIN1 and PPARG gene polymorphisms have been associated with type 2 diabetes, metabolic syndrome, and central obesity. In this study, we hypothesized that genetic variants within LPIN1 and PPARG genes were associated with traits of metabolic syndrome. Correlation between biochemical parameters (including but not limited to, glucose, HbA1c, insulin levels, HDL and LDL cholesterol, triglycerides, serum proteins, liver enzymes) and frequency of polymorphisms in LPIN1 (rs11693809 and rs2716610) and PPARG gene (rs10865710, rs3856806 and rs1801282), was tested in this study.
The study included 70 patients diagnosed with metabolic syndrome and type 2 diabetes. Two polymorphisms of LPIN1 gene (rs11693809 and rs2716610), and three polymorphisms of PPARG gene (rs10865710, rs385806 and rs1801282) were analyzed by real time PCR and conventional PCR-RFLP methods.
Our analysis revealed correlation between insulin levels and rs11693809 LPIN1 polymorphism in diabetic patients. Also the results of this study showed an association of rs10865710 and rs385806 polymorphism of PPARG with HDL cholesterol and LDL plus total cholesterol levels, respectively.
These data reflect an association of analyzed PPARG and LPIN1 gene polymorphisms with values of insulin, HDL, LDL and total cholesterol witch indicates an important role of these genes in lipid metabolism and pathogenesis of type 2 diabetes and metabolic syndrome.
Medicinski glasnik 02/2011; 8(1):76-83. · 0.06 Impact Factor
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ABSTRACT: Differences in the frequency of distribution of the cytochrome P450 (CYP) allelic variants have been demonstrated between distinct ethnic groups, contributing to observed interindividual variation in drug response. In this study we determined, for the first time, prevalence of the common allelic variants of the polymorphic CYP enzymes, CYP3A4*1B and CYP3A5*3, in the population of Bosnia and Herzegovina (BH).
Genomic DNA was extracted from blood samples collected from 140 unrelated subjects. A real-time PCR was used for the detection of CYP polymorphisms, with the application of the specific TaqMan SNP Genotyping Assay (Applied Biosystems) for CYP3A5*3, while CYP3A4*1B was genotyped by high-resolution melting analysis.
Our results have shown that the distribution of CYP3A4*1B and CYP3A5*3 alleles was in line with the data reported in European Caucasians. We confirmed that CYP3A4*1B mutant allele is rare in Caucasians, being present in only 5.1% individuals. However, CYP3A5*3 polymorphism was found to be predominant in the Bosnian population with an incidence of 94%, similarly to other European populations tested so far. Interestingly, we have demonstrated a strong linkage disequilibrium between CYP3A5*3 and CYP3A4*1B alleles. No significant difference in allele frequencies for CYP3A4*1B and CYP3A5*3 has been shown between male and female subjects participating in our study.
Our data demonstrated the high prevalence of CYP3A5*3 allele in Bosnian population, indicating significance of analysis of CYP3A5 and CYP3A4 polymorphisms and corresponding allele frequencies in specific ethnic groups. Importantly, results of this study may lead to translation of pharmacogenetics and individualized therapeutic approach in current clinical practices in BH.
Medicinski glasnik 02/2011; 8(1):84-9. · 0.06 Impact Factor
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ABSTRACT: In polycystic ovary syndrome (PCOS), insulin resistance (IR) appears with high prevalence and represents the major cause of cardiometabolic complications. Lipin 1beta regulates lipid metabolism and augments insulin sensitivity. The impact of lipin 1beta expression in visceral and subcutaneous adipose tissue of PCOS patients on IR was studied for the first time.
Eighty-five PCOS patients and 44 controls were enrolled for subcutaneous tissue biopsy, of whom 25 patients and 30 controls also underwent visceral adipose tissue biopsy. Gene expression of lipin 1beta was measured, together with that of peroxisome proliferator-activated receptor gamma, lipoprotein lipase, hormone-sensitive lipase, adiponectin and glucose transporter 4 in subcutaneous and visceral adipose tissue. Markers of obesity, IR and PCOS were also measured.
In PCOS patients, lipin 1beta expression in both adipose depots was lower than in controls: 0.76 (0.67-0.84) vs 1.16 (0.90-1.43) for visceral and 0.91 (0.73-1.10) vs 1.30 (1.03-1.57) for s.c. depot (both P<10(-4)). The difference remained significant after adjustment for body mass index (BMI) and also when comparing only lean patients with lean controls. In PCOS patients, visceral adipose lipin 1beta expression correlated negatively with homeostasis model assessment-IR (r=-0.474, P=0.017), BMI (r=-0.511, P=0.009) and waist circumference (r=-0.473, P=0.017), waist circumference remaining significant (P=0.027) in multiple regression. Subcutaneous lipin 1beta expression in PCOS correlated negatively with BMI, waist circumference and plasma triglycerides, and positively with high density lipoprotein-cholesterol. Subcutaneous, but not visceral lipin 1beta expression, correlated positively with the studied genes.
Lipin 1beta appears to be involved in the pathogenesis of IR in PCOS.
European Journal of Endocrinology 11/2008; 159(6):833-9. · 3.42 Impact Factor
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ABSTRACT: The insulin-resistant state of the polycystic ovary syndrome (PCOS) was found to be associated with a decreased glucose transporter GLUT4 expression in the insulin target tissues. This study was performed to explore whether the well-known clinical, hormonal and metabolic efficacy of metformin or rosiglitazone treatment is reflected in the modulation of adipocyte GLUT4 mRNA expression in patients with PCOS.
We enrolled 35 women with PCOS. They received either metformin or rosiglitazone for 6 months. A history, blood samples for the measurement of androgens and s.c. adipose tissue samples were taken at baseline and end point. Quantification of GLUT4 mRNA expression in adipose tissue was performed using real-time quantitative PCR. Homeostasis model assessment (HOMA(IR)) score calculation was applied as a measure for insulin resistance (IR).
GLUT4 mRNA expression in adipose tissue increased significantly in both groups (P<0.001). The increase was more pronounced in the rosiglitazone group (P=0.040). There was a statistically significant improvement of HOMA(IR) in both groups (P=0.008). After treatment, frequencies of menstrual bleeding were significantly higher (P<0.001) and serum total testosterone levels significantly lower in both groups (P=0.001).
A 6-month therapy with insulin sensitizers resulted in marked improvement in adipose tissue GLUT4 mRNA expression in PCOS patients, rosiglitazone being more effective when compared with metformin. The augmentation of the insulin signal transduction was accompanied by a significant improvement of HOMA(IR), menstrual pattern and androgen profile.
European Journal of Endocrinology 07/2008; 158(6):793-801. · 3.42 Impact Factor
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ABSTRACT: Insulin resistance is a state in which higher than normal concentrations of insulin are required for normal response. The most common underlying cause is central obesity, although primary insulin resistance in normal-weight individuals is also possible. Excess abdominal adipose tissue has been shown to release increased amounts of free fatty acids which directly affect insulin signalling, diminish glucose uptake in muscle, drive exaggerated triglyceride synthesis and induce gluconeogenesis in the liver. Other factors presumed to play the role in insulin resistance are tumour necrosis factor alpha, adiponectin, leptin, IL-6 and some other adipokines. Hyperinsulinaemia which accompanies insulin resistance may be implicated in the development of many pathological states, such as hypertension and hyperandrogenaemia. Insulin resistance underlies metabolic syndrome and is further associated with polycystic ovary syndrome and lipodystrophies. When beta-cells fail to secrete the excess insulin needed, diabetes mellitus type 2 emerges, which is, besides coronary heart disease, the main complication of insulin resistance and associated diseases.
Clinica Chimica Acta 02/2007; 375(1-2):20-35. · 2.54 Impact Factor
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ABSTRACT: We determined the frequency of galactose-1-phosphate uridyl transferase gene mutations: Q188R, K285N, and the Duarte allelle in 86 patients with idiopathic premature ovarian failure (POF) and 95 controls. No association of the mutations with POF was found.
Fertility and sterility 08/2005; 84(1):253-5. · 3.97 Impact Factor
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ABSTRACT: In a retrospective case-control study, the frequencies of Q188R, K285N, N314D, and IVS5-24G>A mutations were determined with the use of polymerase chain reaction and restriction fragment length polymorphism in the group of infertile women and the controls. No statistically significant differences were observed in the allele frequencies between the infertile women and control groups.
Fertility and Sterility 04/2005; 83(3):776-8. · 3.56 Impact Factor
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ABSTRACT: Numerous mutations in the galactose-1-phosphate uridyl transferase (GALT) gene have been found to impair GALT activity to different extent, causing galactosemia. This disorder exhibits considerable allelic heterogeneity in different populations and ethnic groups. The Q188R mutation accounts for 60-70% of classical galactosemia alleles in the Caucasian population. Individuals homoallelic for Q188R have a severe phenotype with complete loss of enzyme activity. Another form of GALT deficiency is Duarte galactosemia with N314D mutation associated alleles (Duarte-2). Although heterozygotes for classical galactosemia are asymptomatic at birth and Duarte galactosemia appears to be quite benign, there are some indications that these disorders can increase the risk of developing certain diseases later in life. The aim of our study was to analyze a healthy Slovenian population for the frequencies of Q188R and N314D mutations, and for the Duarte-2 indicative intronic variation IVS5-24G>A. DNA samples from 174 healthy subjects were analyzed for all three mutations by polymerase chain reaction and digestion with restriction enzymes. Allele frequencies for Q188R and N314D mutations and IVS5-24G>A intron variation were found to be 0.29%, 8.0% and 5.7%, respectively. These results correlate well with those reported for most other healthy Caucasian populations.
Clinical Chemistry and Laboratory Medicine 11/2002; 40(11):1109-13. · 2.15 Impact Factor
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ABSTRACT: Polymorphisms in HSD11B1, the gene encoding 11β-hydroxysteroid dehydrogenase type 1 enzyme, have been associated with obesity, metabolic syndrome, and type 2 diabetes. In this study, we present an optimized high-resolution melting (HRM) method for genotyping two common polymorphisms of the HSD11B1 gene: rs846910: G>A and rs45487298: insA.
One hundred DNA samples from patients with polycystic ovary syndrome and healthy controls were genotyped by HRM. The results were compared with those obtained with classic polymerase chain reaction followed by restriction fragment length polymorphism analysis.
Various approaches were used during HRM specificity optimization. With the optimized method, genotyping accuracy of 100% was achieved.
HRM analysis is a fast, simple, and cost-effective method compared with the alternative genotyping approaches. The work required for optimizing the method (improvement of specificity) is minor compared to the advantages.
Genetic Testing and Molecular Biomarkers 15(1-2):43-9. · 1.11 Impact Factor
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ABSTRACT: Insulin resistance is a state of impaired responsiveness to insulin action. The most common underlying cause is central obesity although primary insulin resistance in normal-weight individuals is also possible. Excess abdominal adipose tissue has been shown to release increased amounts of tumor necrosis factor α and free fatty acids, which directly affect insulin signaling, diminish glucose uptake in the muscle, drive exaggerated triglyceride synthesis and induce gluconeogenesis in the liver. Other factors presumed to play a role in insulin resistance are adiponectin (a decrease), leptin, IL-6 and some other adipokines. Common obesity is thought to be of polygenic origin with influence of "obesogenic" environment, i.e. increased food intake and the lack of physical activity. Today's high prevalence of obesity could be explained by evolutionary pressure for selection of genes promoting fat storage to survive in starvation. Insulin resistance frequently coexists with central obesity, hypertension and dyslipidemia, which have collectively been denoted as metabolic syndrome. These manifestations represent strong risk factors for diabetes mellitus type 2 and cardiovascular disease.
Biochemia Medica (biochemia-medica@hdmb.hr); Vol.16 No.1.
