Belgin Süsleyici Duman

Effect of abdominal obesity on insulin resistance and the components of the metabolic syndrome: Evidence supporting obesity as the central feature

Background: Metabolic syndrome includes abdominal obesity, diabetes type 2, hypertension, dyslipidemia, derangements of fibrinolysis, and atherosclerosis. Since abdominal obesity is one of the major components of the insulin resistance syndrome (IRS), an attempt was made to evaluate the interrelationships between the magnitude of obesity and the components of the syndrome. Methods: A cross-sectional study of 123 subjects with type 2 diabetes, of whom 31 were normal body weight and 92 had varying degrees of obesity was conducted. The participants were investigated in terms of clinical and laboratory findings of IRS. Fasting and 30-min (early) plasma glucose and serum insulin excursions in response to oral glucose challenge (75 g) were determined. The peripheral and hepatic insulin resistance (insensitivity) was calculated by homeostasis model assessment (HOMA). Results: Clinical and biochemical findings were compared with the components of the IRS, and demonstrated that a rise in fasting as well as 30-min insulin secretion increases as abdominal body fat (obesity) increases. There was also a significant and proportional correlation between the magnitude of abdominal obesity and the components of metabolic syndrome. Conclusion: Abdominal adiposity appears to have a pivotal role in the development of IRS.

Vitamin D receptor alleles, bone mineral density and turnover in postmenopausal osteoporotic and healthy women.

Objective: Vitamin D receptor (VDR) gene polymorphisms and bone metabolic markers were investigated as potential genetic markers for osteoporosis in postmenopausal Turkish women. The relationship between their VDR gene polymorphisms and bone states was determined. Materials and Methods: Restriction fragment length polymorphisms at the VDR gene locus (i.e., for BsmI, ApaI, and TaqI) was investigated in 75 postmenopausal osteoporotic (53.16 ± 1.31 years) and 66 healthy (52.62 ± 1.69 years) Turkish women and the genotypes were related to bone mineral density (BMD) at femoral neck (FN), lumbar spine (L1–4), trochanter, Ward’s triangle (Ward’s) and metabolic parameters of bone turnover. Results: In osteoporotic women, TaqI genotype-related differences of the VDR gene were found to be significant at all BMD sites; TT genotype had higher L1–4 BMD values than Tt and tt (p < 0.05); tt genotype had significantly lower BMD at FN (p < 0.05), trochanter (p < 0.01), and Ward’s (p < 0.05) compared to TT genotype. The tt genotype was found to be associated with higher (p < 0.05) serum osteocalcin levels compared to Tt and TT genotypes in the osteoporotic women, whereas no such association was found for the healthy women. Conclusion: Our data showed an association between VDR TaqI genotype and BMD at the FN, L1–4, trochanter and Ward’s triangle in nonobese postmenopausal osteoporotic women. Thus the VDR gene Taql polymorphism modulates differences in BMD in the postmenopausal osteoporotic women.

Lipoprotein Lipase Gene Polymorphism and Lipid Profile in Coronary Artery Disease

CONTEXT Lipoprotein lipase (LPL) plays a central role in lipid metabolism, hydrolyzing triglyceride in chylomicrons and very-low-density lipoproteins. The PvuII polymorphic variant of LPL gene is common and might affect risk of coronary artery disease (CAD). OBJECTIVE Our aim was to determine whether LPL- PvuII polymorphism can be considered to be an independent risk factor or a predictor for CAD in Turkish subjects. DESIGN We used polymerase chain reaction and restriction enzyme digestion to determine the distribution of the previously described C-->T transition that causes a PvuII polymorphism in intron 6 among healthy blood donors of Turkish origin and among angiographically confirmed CAD patients with comparable ethnic backgrounds. RESULTS For the PvuII genotypes, within the CAD group (n = 80), the +/- genotype was found in 39 individuals (48.8%), whereas 25 (31.3%) carried the +/+ genotype, and 14 (17.5%) carried the -/- genotype. Within the control group (n = 49), the -/- genotype was found in 19 individuals (38.8%), 16 (32.7%) carried the +/- genotype, and 14 (28.6%) carried the +/+ genotype. The genotype frequency distribution was significantly different (P =.049) in the CAD and control study groups. The most frequent genotype among CAD patients was +/-; this genotype was more frequent in patients than in control subjects. However, the -/- genotype was more prevalent in the control group. Lipoprotein lipase-PvuII polymorphism was found to be associated with fasting total cholesterol and low-density lipoprotein cholesterol levels. The +/+ genotype was found to have higher levels of total cholesterol and low-density lipoprotein cholesterol in both the CAD and control groups. CONCLUSION There was a difference in the distribution of LPL-PvuII genotypes between the healthy subjects and the patients with CAD. Lipoprotein lipase-PvuII polymorphisms were not detected as independent risk factors for CAD in this study group, but had associations with lipid levels.

Genetic variations of the apolipoprotein B gene in Turkish patients with coronary artery disease

Background: The results of studies that clarify the association of genetic markers at the apolipoprotein B (apo B) gene (EcoRI and XbaI polymorphisms) with coronary artery disease (CAD) are not consistent and suggest that the effect is context dependent (dependent on ethnicity and sex). The present study represents the first investigation of the apo B gene polymorphisms in Turkish patients with CAD and their influence on lipid levels. Aim: The study investigated the association of apo B gene EcoRI and XbaI polymorphisms with CAD and with variation in lipid levels (total cholesterol (T-Chol), high-density lipoprotein cholesterol (HDL-Chol), low-density lipoprotein cholesterol (LDL-Chol), and triacylglycerol (TAG)). Subjects and methods: The study group was composed of 150 individuals with angiographically documented CAD and 100 angiographically proven to be healthy controls. PCR-RFLP was used to determine the DNA polymorphisms of the apo B gene. Results: The frequencies of apo B genotypes detected with EcoRI (AA, AG, GG) and XbaI (CC, CT, TT) did not differ significantly between case and control subjects. A significant association between EcoRI genotypes and T-Chol (p ≤ 0.05), and LDL-Chol (p ≤ 0.001) was observed only in CAD patients. Patients with the AA genotype had higher levels of serum T-Chol and LDL-Chol compared with AG. With logistic regression analysis the XbaI TT genotype was found to be associated with CAD prevention. However, no significant differences in lipid variables were determined for the XbaI polymorphisms in the patients with CAD. Conclusions: Apo B EcoRI genotypes were not found as risk factors for CAD, whereas XbaI TT genotype was detected to prevent against CAD in our study group. Résumé. Arrière plan: Les résultats des études qui clarifient l’association des marqueurs génétiques du gène B (apo B) de l’alipoprotéine (polymorphismes EcoRI et XbaI) avec la maladie coronarienne (MC), ne sont pas satisfaisants et suggèrent que l’effet est dépendant du contexte (dépendance par rapport au sexe et à l’ethnicité). Cette étude est la première recherche sur les polymorphismes EcoRI et XbaI du gène apo B chez des patients turcs souffrant de MC et sur leur influence sur les niveaux lipidiques. But: L’étude explore l’association des polymorphismes EcoRI et XbaI du gène apo B avec la MC et avec la variation des niveaux lipidiques : cholestérol total (Chol-T), cholestérol de lipoprotéines de haute densité (Chol-LHD), cholestérol de lipoprotéines de basse densité (Chol-LBD) et glycéroltriacyl (GTA) Sujets et méthodes. Le groupe étudié est composé de 150 individus présentant une angiographie de MC et de 100 individus a angiographie saine. La technique de RFLP-PCR a été utilisée pour déterminer les polymorphismes d’ADN du gène apo B. Résultats: Les fréquences des génotypes de apo B détectées avec EcoRI (AA, AG, GG) et XbaI (CC, CT, TT) ne diffèrent pas significativement entre patients et contrôles. Une association significative entre génotypes EcoRI et Chol-T (p ≤ 0,05) ainsi qu’avec Chol-LBD (p ≤ 0,001) n’a été observée que chez les patients à MC. Les patients de génotype AA ont un niveau plus élevé que ceux de génotype AG pour les niveaux de Chol-T et de Chol-LBD dans le sérum. Par analyse de régression logistique, on trouve que le génotype XbaI TT est associé à la prévention de la MC. On n’a cependant pas trouvé de différence significative des variables lipidiques qui serait déterminée par les polymorphismes XbaI chez les patients MC. Conclusion: Les génotypes apo B EcoRI n’apparaissent pas être des facteurs de risque pour la MC, tandis qu’il apparaît que le génotype XbaI TT protège de la MC dans le groupe étudié. Zusammenfassung. Hintergrund: Die Ergebnisse von Studien, die die Beziehung zwischen genetischen Markern auf dem Apolipoprotein B (Apo B)-Gen und koronarer Herzkrankheit (coronary artery disease, CAD) klären, sind nicht vereinbar und legen nahe, dass der Einfluss vom Zusammenhang abhängt (je nach ethnischer Zugehörigkeit und Geschlecht). Die vorliegende Studie ist die erste Untersuchung von Apo B-Gen-Polymorphismen und ihrem Einfluss auf Lipidspiegel bei Türkischen Patienten mit CAD. Ziel: Die Studie untersuchte die Beziehung von Apo B-Gen EcoRI- und XbaI-Polymorphismen mit CAD und mit der Schwankung der Lipidspiegel (Gesamtcholesterin (total cholesterol, T-Chol), High-density lipoprotein Cholesterin (HDL-Chol), Low-density lipoprotein Cholesterin (LDL-Chol) und Triacylglycerol (TAG)). Probanden und Methoden: Die Studiengruppe bestand aus 150 Personen mit angiographisch dokumentierter CAD und 100 angiographisch gesicherten gesunden Kontrollen. PCR-RFLP wurden benutzt um DNS-Polymorphismen des Apo B-Gens zu bestimmen. Ergebnisse: Die Häufigkeiten der Apo B-Genotypen, die mit EcoRI (AA, AG, GG) und XbaI (CC, CT, TT) bestimmt wurden, unterschieden nicht signifikant zwischen Patienten und Kontrollpersonen. Eine signifikante Beziehung zwischen EcoRI-Genotypen und T-Chol (p ≤ 0,05) und LDL-Chol (p ≤ 0,001) wurde nur bei CAD-Patienten beobachtet. Patienten mit dem Genotyp AA hatten höhere Serumspiegel von T-Chol und LDL-Chol, verglichen mit AG. Unter Verwendung einer logistischen Regressionsanalyse fand sich, dass der XbaI TT-Genotyp vor CAD schützt. Allerdings wurden keine signifikanten Unterschiede bei den Lipidvariablen hinsichtlich von XbaI-Polymorphismen bei Patienten mit CAD gefunden. Zusammenfassung: Es wurde nicht gefunden, dass Apo B EcoRI-Genotypen Risikofaktoren für das Auftreten einer CAD darstellen, allerdings zeigte sich in unserer Studiengruppe, dass der XbaI TT-Genotyp gegen CAD schützt. Resumen. Antecedentes: Los resultados de los estudios que tratan de aclarar la asociación de los marcadores genéticos en el gen de la apolipoproteína B (apo B) (polimorfismos EcoRI y XbaI) con la enfermedad arterial coronaria (EAC), no son consistentes y sugieren que el efecto depende del contexto (es dependiente de la etnicidad y del sexo). El presente estudio constituye la primera investigación sobre los polimorfismos del gen apo B en pacientes turcos con EAC y su influencia sobre los niveles lipídicos. Objetivo: El estudio investigó la asociación de los polimorfismos EcoRI y XbaI del gen apo B con la EAC y con la variación en los niveles lipídicos (colesterol total (Col-T), colesterol asociado a lipoproteínas de alta densidad (Col-HDL), colesterol asociado a lipoproteínas de baja densidad (Col-LDL) y triacilglicerol (TAG)). Sujetos y Métodos: El grupo estudiado estaba compuesto por 150 individuos con EAC documentada angiográficamente y 100 controles sanos, comprobados mediante un angiograma. Se utilizó la PCR-RFLP para determinar los polimorfismos del ADN del gen apo B. Resultados: Las frecuencias de los genotipos apo B detectados con EcoRI (AA, AG, GG) y XbaI (CC, CT, TT) no diferían significativamente entre los casos y los controles. Se observó una asociación significativa entre los genotipos EcoRI y los niveles de Col-T (p ≤ 0,05) y Col-LDL (p ≤ 0,001), sólo en pacientes con EAC. Los pacientes con el genotipo AA tenían niveles más altos de Col-T y de Col-LDL séricos comparados con los de genotipo AG. Mediante un análisis de regresión logística se encontró que el genotipo XbaI TT estaba asociado con la prevención de la EAC. Sin embargo, en los pacientes con EAC no se encontraron diferencias significativas en las variables lipídicas para los polimorfismos XbaI. Conclusiones: No se ha encontrado que los genotipos apo B EcoRI sean factores de riesgo para la EAC, mientras que se detectó que el genotipo XbaI TT prevenía contra la EAC en el grupo estudiado.

Polymorphisms at the Ligand Binding Site of the Vitamin D Receptor Gene and Osteomalacia

Vitamin D receptor (VDR) gene polymorphisms have been suggested as possible determinants of bone mineral density (BMD) and calcium metabolism. In this study, our aim was to determine whether there is an association between VDR gene polymorphism and osteomalacia or not. We determined ApaI and TaqI polymorphisms in the vitamin D receptor gene in 24 patients with osteomalacia and 25 age-matched healthy controls. Serum calcium, phosphorus, ALP, PTH, 25OHD levels were also examined. We used PCR and RFLP methods to test for an association between osteomalacia and polymorphisms within, intron 8 and exon 9 of the VDR gene. When the control and patients were compared for their ApaI and TaqI genotypes there was no relationship between VDR gene allelic polymorphisms and osteomalacia. Whereas a nearly significant difference for A allele was found in the allellic distribution of the patients (p = 0.08). Also no association between biochemical data and VDR gene polymorphisms was observed.