Tamara Božina

Association between lamotrigine concentrations and ABCB1 polymorphisms in patients with epilepsy.

Background: Epilepsy is treated with a variety of anticonvulsants that are often used concomitantly. Therefore, therapeutic drug monitoring is often necessary. Along with clinical and environmental factors, genetic predisposition has been recognized to be relevant for interindividual variability in drug response. Polymorphic transporter proteins such as P-glycoprotein significantly influence pharmacokinetics and bioavailability of many structurally unrelated drugs. The aim of the study was to evaluate the impact of polymorphisms in the P-glycoprotein–encoding gene ABCB1 (C1236T, G2677T/A, C3435T) on antiepileptic drug disposition. Methods: We recruited 222 patients with epilepsy who were prescribed lamotrigine in monotherapy or polytherapy. Lamotrigine plasma concentrations were analyzed and compared with ABCB1 gene variants. The ABCB1 genotyping was performed by real-time polymerase chain reaction methods. The therapeutic drug monitoring was performed by high-performance liquid chromatography–diode array detector (DAD) and immunoassay. Results: A significant correlation was confirmed between lamotrigine concentration and additional drugs (P < 0.001). In the whole group, statistical analysis showed correlations between lamotrigine concentrations and ABCB1 C1236T variants: 10.1 and 6.5 &mgr;mol/L for CC versus CT + TT, respectively (P = 0.021), and for dose corrected lamotrigine 0.068 and 0.053 &mgr;mol·L−1·mg−1, for CC versus CT + TT, respectively (P = 0.017). Analysis of a specific haplotype showed that 1236C–2677G–3435C carriers had higher lamotrigine concentrations than 1236T–2677G–3435T carriers (P < 0.001), followed by 1236T–2677T–3435C carriers (P < 0.001). Conclusions: ABCB1 C1236T, G2677T/A, C3435T polymorphisms have an influence on lamotrigine serum concentrations.

Adiponectin Level and Gene Variability Are Obesity and Metabolic Syndrome Markers in a Young Population

BACKGROUND AND AIMS Human obesity is accepted as an important risk factor for development of MetS. Adiponectin is linked to central obesity and ADIPOQ variants are promising markers for understanding the genetic base of obesity-related disorders. We performed analyses of adiponectin concentrations and ADIPOQ variants and tested their associations with obesity and MetS in young subjects of Croatian origin. METHODS Biochemical and anthropometric parameters of MetS were obtained for 149 unrelated subjects. Adiponectin levels were measured by ELISA assay. ADIPOQ -11391G>A and -11377C>G were genotyped by real-time PCR. RESULTS BMI and WC, TG and GLUC showed inverse correlation, whereas HDL-C showed a positive correlation with adiponectin concentrations. For central obesity, we found association with -11377C>G and with -11391G>A polymorphisms. ADIPOQ -11377GG and -11391GA significantly increased the risk for the development of central obesity (OR 5.57 and OR 3.37, respectively). Significant association was found between -11391A, -11377G allele and haplotype and increased TG. -11377C>G and -11391G>A variant were significantly associated with the incidence of MetS. C>G mutation at position -11377 significantly increased the risk of MetS development (OR = 2.93). Compared with the -11391G homozygotes, carriers of the A allele had a significantly increased risk for the development of MetS (OR = 3.15). The test of overall association showed a statistically significant correlation of MetS with -11377C>G and -11391G>A haplotypes (p = 0.008). CONCLUSIONS Analysis of adiponectin concentration and ADIPOQ -11391G>A and -11377C>G gene variants may be clinically meaningful for estimation of MetS risk in a young population.

Suicide ideators and attempters with schizophrenia – The role of 5-HTTLPR, rs25531, and 5-HTT VNTR Intron 2 variants

AIM To examine the role of 5-HTTLPR, rs25531 and 5-HTT VNTR Intron 2 variants in subjects with psychotic disorders manifesting suicide ideation and behaviour. METHODS The study included 519 subsequently hospitalized subjects who were genotyped for 5-HTTLPR, rs25531 and 5-HTT VNTR In2 variants. Clinical assessments included structured psychiatric interview, sociodemographic characteristics, suicide ideation and behaviour (SIBQ), severity of psychopathology (PANSS) and depression (CDSS). RESULTS Three subgroups were identified: suicide attempters (N = 161), suicide ideators (N = 174) and subjects who never reported suicide ideation or behaviour (comparative group, N = 184). MAJOR FINDINGS 1) Suicide attempters scored highest on the CDSS, while no differences between the three clinical subgroups were detected in the PANSS scores; 2) Suicide attempters were more frequently the carriers of L(A) allele, while subjects in the comparative group were more frequently the carriers of low expression 5-HTTLPR/5-HTT rs25531 haplotype SL(G); 3) No difference was found between the three clinical groups in the 5-HTT VNTR In2 variants; 4) Subjects with 5-HTTLPR/5-HTT rs25531 intermediate expression haplotype (L(A)L(G,)SL(A)) scored higher on the PANSS general psychopathology subscale; 5) There was no association between suicide attempt or ideation and 5-HTTLPR/In2 or 5-HTTLPR/rs25531/In2 haplotype distribution. CONCLUSION The suicide ideators, attempters and controls did not differ significantly in 5-HTTLPR or 5-HTT VNTR In 2 variants, but 5-HTTLPR/5-HTT rs25531 haplotype might be a useful genetic marker in distinguishing these three clinical groups.

Clinical application of genotype-guided dosing of warfarin in patients with acute stroke

BACKGROUND Patients with certain types of stroke need urgent anticoagulation and it is extremely important for them to achieve fast and stable anticoagulant effect and receive individualized treatment during the initiation of warfarin therapy. METHODS We conducted a prospective study among 210 acute stroke patients who had an indication for anticoagulation and compared the impact of CYP2C9 and VKORC1 genotype-guided warfarin dosing (PhG) with fixed dosing (NPhG) on anticoagulation control and clinical outcome between groups. RESULTS PhG achieved target INR values earlier, i.e., on average in 4.2 (4.1-4.7, 95% CI) days compared to NPhG (5.2 days [4.7-6.4, 95% CI]) (p = 0.0009), spent a higher percentage of time in the therapeutic INR range (76.3% [74.7-78.5, 95% CI] vs. 67.1% [64.5-69.6, 95% CI] in NPhG), and spent less time overdosed (INR > 3.1) (PhG 0.4 [0.1-0.7, 95% CI], NPhG 1.7 [1.1-2.3, 95% CI] days; p >0.000). PhG reached stable maintenance dose faster (10 [9.9-10.7, 95% CI] vs. 13.9 [13.3-14.7, 95% CI] days in controls; p = 0.0049) and had a better clinical outcome in relation to neurological deficit on admission as compared to NPhG. CONCLUSION We confirmed that warfarin therapy with genotype-guided dosing instead of fixed dosing reduces the time required for stabilization and improves anticoagulant control with better clinical outcome in early stages of warfarin therapy introduction among acute stroke patients, which is essential for clinical practice.

Interaction of genetic risk factors confers increased risk for metabolic syndrome: the role of peroxisome proliferator-activated receptor γ.

AIM The aim of the study was to estimate the influence of interactions between peroxisome proliferator-activated receptor γ (PPARγ) and target genes lipoprotein lipase (LPL), interleukin 6 (IL6), angiotensin converting enzyme (ACE), and angiotensin II type 1 receptor (AT1R) on metabolic syndrome (MetSy) and its traits. METHODS The study included 527 participants (263 with MetSy and 264 controls). Genotyping of PPARγ Pro12Ala, LPL PvuII (-/+), IL6 -174G>C, ACE I/D and AT1R 1166A>C was performed using polymerase chain reaction-restriction fragment length polymorphism-based methods. RESULTS Interaction between PPARγ Pro12Ala and LPL Pvu(-/+) improved prediction of MetSy over and above prediction based on a model containing no interactions (χ(2)=7.22; df=1; p=0.007). In the group of participants with PPARγ Pro12Ala or Ala12Ala genotypes, those with the LPL Pvu (-/+) or (+/+) genotype had greater odds for MetSy (odds ratio OR=5.98; 95% confidence interval CI: 1.46-24.47, p=0.013). Interaction between PPARγ Pro12Ala and IL6 -174G>C improved prediction of high fasting blood glucose (χ(2)=13.99; df=1; p<0.001). PPARγ Ala12 variant was found protective in patients with IL6 -174GG genotype (OR=0.10; 95% CI: 0.02-0.57, p=0.01), while in the case of IL6 -174C allele carriers, for PPARγ Ala12 carriers, larger odds for high glucose levels compared with Pro12 variant were observed (OR=2.39; 95% CI: 1.11-5.17, p=0.026). Interactions of PPARγ and ACE were significant for BMI. In the group with ACE DD genotype, those with PPARγ Pro12Ala or Ala12Ala genotype have greater odds for obesity (OR=9.98; 95% CI: 1.18-84.14, p=0.034). CONCLUSIONS PPARγ gene variants can, in interaction with some of its target genes, modulate physiological processes leading to the development of MetSy.

Genetic polymorphisms of cytochrome P450 enzymes: CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 in the Croatian population

BACKGROUND Data on the frequency of pharmacogenetic polymorphisms in the Croatian population are limited. We determined and analyzed frequencies for the most important CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 genetic variants in the Croatian population. METHODS 2637 subjects were included. Genotyping was performed by real-time polymerase chain reaction (PCR) using TaqMan® DME or TaqMan® SNP Genotyping Assays, and by PCR, and PCR-RFLP analysis. RESULTS For CYP2C9, allele frequencies of *2 and *3 variant were 14.5% and 7.6%, respectively. Among them, 3.98% of subjects were predicted to be poor metabolizers. For CYP2C19, the most frequent variant alleles were *2 (14.8%), and *17 (23.7%), while 2.4% of subjects were predicted to be poor metabolizers, and 5.39% were homozygous carriers of *17 predicted to be ultrarapid metabolizers (UM). For CYP2D6, the frequencies of tested variant alleles were *3 (2.2%), *4 (17.4%), *5 (1%), *6 (1.1%), and *41 (10.8%). Out of these, 5.59% were predicted to be poor metabolizers, 3.19% were classified as UM while 1.0% were carriers of variant alleles duplications (undefined phenotype). For CYP3A4 allele frequencies of *1B and *22 variants were 1.4% and 2.7%, respectively. Allele frequency of CYP3A5*3 was 95.5%. Analyzing CYP3A cluster according to the combination of CYP3A4*22 and CYP3A5*3 revealed 5.34% of subjects to be poor metabolizers, while 8.66% were classified as extensive metabolizers. CONCLUSIONS The frequency of the CYP allelic variants, genotypes, and predicted phenotypes in the Croatian population is in accordance with the other European populations, between the values of published data for Middle European and Mediterranean populations.Abstract Background: Data on the frequency of pharmacogenetic polymorphisms in the Croatian population are limited. We determined and analyzed frequencies for the most important CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 genetic variants in the Croatian population. Methods: 2637 subjects were included. Genotyping was performed by real-time polymerase chain reaction (PCR) using TaqMan® DME or TaqMan® SNP Genotyping Assays, and by PCR, and PCR-RFLP analysis. Results: For CYP2C9, allele frequencies of *2 and *3 variant were 14.5% and 7.6%, respectively. Among them, 3.98% of subjects were predicted to be poor metabolizers. For CYP2C19, the most frequent variant alleles were *2 (14.8%), and *17 (23.7%), while 2.4% of subjects were predicted to be poor metabolizers, and 5.39% were homozygous carriers of *17 predicted to be ultrarapid metabolizers (UM). For CYP2D6, the frequencies of tested variant alleles were *3 (2.2%), *4 (17.4%), *5 (1%), *6 (1.1%), and *41 (10.8%). Out of these, 5.59% were predicted to be poor metabolizers, 3.19% were classified as UM while 1.0% were carriers of variant alleles duplications (undefined phenotype). For CYP3A4 allele frequencies of *1B and *22 variants were 1.4% and 2.7%, respectively. Allele frequency of CYP3A5*3 was 95.5%. Analyzing CYP3A cluster according to the combination of CYP3A4*22 and CYP3A5*3 revealed 5.34% of subjects to be poor metabolizers, while 8.66% were classified as extensive metabolizers. Conclusions: The frequency of the CYP allelic variants, genotypes, and predicted phenotypes in the Croatian population is in accordance with the other European populations, between the values of published data for Middle European and Mediterranean populations.

Adiponectin is Not Associated With Blood Pressure in Normotensives and Untreated Hypertensives With Normal Kidney Function

AbstractThe role of adiponectin in hypertension is still a matter of debate. Obtained conflicting results could be mostly explained with diversity of subjects included in different studies. Our aim was to analyze association of adiponectin with blood pressure (BP) in a group of normotensive and untreated hypertensive subjects.Participants (N = 257) were selected from a random sample of 2487 subjects enrolled in an observational cross-sectional study. Subjects with diabetes and chronic kidney diseases were excluded. BP was measured using Omron M6 device following ESH/ESC guidelines. Adiponectin concentration was determined by ELISA.There were no differences in adiponectin values (mg/L) between hypertensives and normotensives (median 9.75; iqr: 7.44–17.88 vs 11.35; iqr: 7.43–12.63; P = 0.17). On univariate linear regression adiponectin was not associated with systolic or diastolic BP (P > 0.05). Furthermore, multivariate analysis did not show significant contribution of log-transformed adiponectin either to systolic (&bgr; = −0.040; P = 0.43) or diastolic BP (&bgr; = 0.066; P = 0.33).In our group of normotensives and untreated hypertensives with normal kidney function adiponectin was not associated with BP even after adjustment for other risk factors. Our results and conclusions should not be extrapolated to subjects with other characteristics.

Is there any association of apolipoprotein E gene polymorphisms with metabolic syndrome in a young population of Croatian origin

Abstract Background: Apolipoprotein E has an important role in lipid metabolism and adipocyte activity and apo E gene (APOE) might serve as a potential determinant of metabolic syndrome (MetS). Aim: The aim of the presented study was to investigate the association between APOE polymorphism and MetS in young adult subjects of Croatian origin. Methods: This study measured biochemical and anthropometric parameters of 149 young (aged 20–33) subjects. The APOE was genotyped by real-time PCR. Results: No APOE genotype significantly increased the risk for development of MetS. Significant association was found between APOE polymorphism and elevated blood pressure (EBP) (p = .019). The carriers of the ɛ4 allele had decreased risk for EBP (OR = 0.28, 95% CI) compared to ɛ3 allele carriers (ɛ3 allele vs others, χ2 = 7.08; p = .005). APOE alleles were significantly associated with the concentration of TC and LDL-C (χ2 = 12.11, p = .002 and χ2 = 15.76, p < .001, respectively). With diet as a modification covariate there was a significant correlation of APOE alleles with the concentrations of adiponectin and leptin (χ2 = 7.076; p = .029 and χ2 = 7.46; p = .024, respectively). Conclusion: Although APOE variants were not confirmed as the risk factor for development of MetS, the APOE alleles were associated with some of the metabolic parameters in young Croatian subjects. The relation of APOE alleles with a concentration of adiponectin and leptin depends on the diet intake.