An association between rs7635818 polymorphism located on chromosome 3p12.3 and the presence of abdominal aortic aneurysm

The association between gene variant rs7635818 located on chromosome 3p12.3 and abdominal aortic aneurysm (AAA) was not unambiguously determined by the results of genome-wide association studies. The aim of our study was to examine this possible association in the Slovak population, with respect to the presence and severity of AAA.A cross-sectional study was conducted between August 2016 and March 2020. The study included 329 participans, 166 AAA patients and a control group of 163 subjects without confirmed AAA with comparable distribution of genders. The anteroposterior diameter of the abdominal aorta was determined by duplex ultrasonography. AAA was defined as subrenal aortic diameter ≥ 30 mm. DNA samples were genotyped using real-time polymerase chain reaction and subsequent high-resolution melting analysis in presence of unlabelled probe. Genetic models studying the possible association were adjusted to age, sex, smoking, arterial hypertension, diabetes mellitus, creatinine and body mass index (BMI) in multivariate analysis. In the additive model, presence of each C-allele of rs7635818 polymorphism was associated with an almost 50 % increase in probability of developing AAA (OR 1.49; 95 % CI 1.06-2.08; p=0.020). Compared to GG homozygotes, CC homozygotes had more than two times higher risk of developing AAA (OR 2.23; 95 % CI 1.14-4.39; p=0.020). The risk of AAA was also in the recessive model higher for CC homozygotes compared to G-allele carriers (GC/GG) (OR 1.79; 95 % CI 1.01-3.19; p=0.047).The abdominal aortic diameter in CC homozygotes of the rs7635818 polymorphism was 7.66 mm greater compared to GG homozygotes (42.5±22.0 mm vs 34.8±21.3 mm; p=0.022) and 5.88 mm greater compared to G-allele carriers (GC/GG) (42.5±22.0 mm vs 36.6±21.0 mm; p=0.04) in univariate analysis. C-allele variant in rs7635818 G>C polymorphism is associated with a higher probability of developing AAA in the Slovak population.

Variants in Pharmacokinetic Transporters and Glycemic Response to Metformin: A Metgen Meta-Analysis

Therapeutic response to metformin, a first-line drug for type 2 diabetes (T2D), is highly variable, in part likely due to genetic factors. To date, metformin pharmacogenetic studies have mainly focused on the impact of variants in metformin transporter genes, with inconsistent results. To clarify the significance of these variants in glycemic response to metformin in T2D, we performed a large-scale meta-analysis across the cohorts of the Metformin Genetics Consortium (MetGen). Nine candidate polymorphisms in five transporter genes (organic cation transporter [OCT]1, OCT2, multidrug and toxin extrusion transporter [MATE]1, MATE2-K, and OCTN1) were analyzed in up to 7,968 individuals. None of the variants showed a significant effect on metformin response in the primary analysis, or in the exploratory secondary analyses, when patients were stratified according to possible confounding genotypes or prescribed a daily dose of metformin. Our results suggest that candidate transporter gene variants have little contribution to variability in glycemic response to metformin in T2D.

A missense variant in GLP1R gene is associated with the glycaemic response to treatment with gliptins

Gliptins act by increasing endogenous incretin levels. Glucagon-like peptide-1 receptor (GLP1R) and glucose-dependent insulinotropic peptide receptor (GIPR) are their indirect drug targets. Variants of GLP1R and GIPR have previously been associated with the incretin effect. The aim of the present pilot study was to examine associations of the GLP1R and GIPR gene variants with the glycaemic response to gliptins. A total of 140 consecutive patients with type 2 diabetes were followed-up 6 months after initiation of gliptin treatment. GLP1R rs6923761 (Gly168Ser) and GIPR rs10423928 genotyping was performed using real-time PCR, with subsequent high-resolution melting analysis. The main study outcome was reduction in glycated haemoglobin (HbA1c) after treatment. GLP1R Gly168Ser variant was significantly associated with reduction in HbA1c in an additive model (β = -0.33, p = 0.011). The mean reduction in HbA1c in Ser/Ser homozygotes was significantly lower compared with Gly-allele carriers [0.12 ± 0.23% vs. 0.80 ± 0.09% (1.3 ± 2.5 mmol/mol vs. 8.7 ± 1.0 mmol/mol); p = 0.008]. In conclusion, GLP1R missense variant was associated with a reduced response to gliptin treatment. The genotype-related effect size of ∼0.7% (8 mmol/mol) is equal to an average effect of gliptin treatment and makes this variant a candidate for use in precision medicine.

The effect of alfacalcidiol and metformin on phenotype manifestations in women with polycystic ovary syndrome - a preliminary study

Aim of this study was to evaluate the effect of vitamin D supplementation in obese, insulin resistant and vitamin D deficient PCOS women on biochemical and clinical hyperandrogenism and menstrual irregularity in comparison to effect of metformin or combined metformin plus vitamin D therapy. Thirty nine PCOS women were randomized into three groups and treated with alfacalcidiol (Group 1), combined alfacalcidiol and metformin therapy (Group 2) and metformin (Group 3) for 6 months. Serum TST, fTST, DHEAS, LH and LH/FSH were measured before and after six months of treatment. Menstrual cycle regularity, hirsutism, acne and pregnancy rate were assessed at the same time. There was a significant decrease in TST levels in the Group 2 and slight but not significant decrease in the Group 3. No significant changes in other parameters (fTST, DHEAS, LH, LH/FSH) have been found after 6 months therapy in all three groups. An improvement of menstrual cycle was detected in 78 % of patients in Group 1 (p<0.04), 80 % in the Group 2 (p<0.03) and in 90 % in the Group 3 (p<0.002), respectively. There was no significant improvement of acne and hirsutism in all three groups (all p not significant). Pregnancy rate was higher in the Group 3 as compared with Groups 1 and 2 (67 % vs. 0 % and 25 %, respectively), however without statistical significance. Vitamin D administration has no significant effect on androgen levels and clinical features of hyperandrogenism in obese vitamin D deficient PCOS women. However, it can potentiate effect of metformin on testosterone levels and LH/FSH ratio but not on clinical hyperandrogenism and pregnancy rate.

[Possible influence of genetic polymorphism in the area of GSTs genes on the serum PCB level]

OBJECTIVE

To find out whether the serum PCB level depends on genetic polymorphism in the area of GSTs genes.

MATERIAL AND METHODS

In the group of 147 men (112 with an average age of 59.1 ± 10.1 and serum PCB level > 1,000 ng/ g lipid -  PCB1, and 35 with an average age of 56.2 ± 12.9 and serum PCB level < 700 ng/ g lipid -  PCB2), the PCR RLFP analysis of DNA was used to determine the genetic polymorphism in the area of GSTs genes.

RESULTS

As regards PCB, an association was found between serum PCB concentrations and the null genotype of GSTT1 gene. Men above the median PCB levels displayed, with significantly greater frequency, the null genotype GSTT1 compared to men below the median PCB levels, both in the PCB1 set and in the PCB2 set. In the PCB1 set, the presence of the null genotype GSTT1 increased the risk of high PCB levels 11- fold, in the PCB2 set 4- fold (p < 0.001). In the PCB2 set, an association was also discovered between GSTP1 Val/ Val genotype and higher PCB levels. The risk of high PCB levels in the individuals with the Val/ Val genotype was 5- fold higher than in the carriers of the Ile allele (p < 0.001). In neither set was the GSTM1 genotype associated with serum PCB concentrations.

CONCLUSION

The association between high PCB levels and the GSTT1 null and GSTP1 Val/ Val suggests that harmful effects depend not only on the intake amounts of PCB but also on the ability of the organism to detoxify these substances. Individuals living in the same environment are therefore at different risks of developing a disease when exposed to PCB. Polymorphism in the area of GSTTl gene (GSTT1 null) could be a potential genetic risk marker.

Pharmacogenomic association between a variant in SLC47A1 gene and therapeutic response to metformin in type 2 diabetes

Pharmacogenetic studies revealed that variants in genes related to the pharmacokinetics of metformin were associated with glucose-lowering effect of metformin. The aim of this study was to investigate possible associations of the variants in genes encoding organic cationic transporters-solute carrier family 22, members A1, A2 (SLC22A1, SLC22A2) and solute carrier family 47, member A1 (SLC47A1) with response to metformin in type 2 diabetes. One hundred forty-eight drug-naive patients with type 2 diabetes were included in the study. Genotyping for SLC22A1 rs622342, SLC22A2 rs316019 and SLC47A1 rs2289669 variants was performed using real-time PCR with subsequent melting-curve analysis. SLC47A1 rs2289669 genotype was significantly associated with the reduction in haemoglobin A1c (HbA1c) after 6 months. Twenty percentage of patients with diabetes that are homozygous for A-allele of SLC47A1 had twofold reduction in HbA1c in comparison with the patients carrying G-allele (GG + GA: 0.55 ± 0.09% vs. AA: 1.10 ± 0.18%, p = 0.018). In conclusion, the results of this study might have in future practical implication in personalised treatment of patients with type 2 diabetes.

Variation in CDKAL1 gene is associated with therapeutic response to sulphonylureas

The aim of the present pilot pharmacogenetic study was to analyse quantitative effects of sulphonylurea treatment in addition to metformin on parameters of glycemic control with respect to CDKAL1 genotypes in patients with type 2 diabetes. Effect of 6-month sulphonylurea therapy on glycemic control according to CDKAL1 genotypes was evaluated in 101 patients with type 2 diabetes who failed to achieve glycemic control on metformin monotherapy. CDKAL1 rs7756992 polymorphism was determined by melting curve analysis of small amplicon following real-time PCR. After sulphonylurea treatment fasting plasma glucose (FPG) levels were significantly different (p=0.045) among three CDKAL1 genotype groups (AA: n=49; AG: n=36; GG: n=16). In a dominant genetic model, carriers of the G-allele (AG+GG, n=52) achieved significantly lower FPG levels in comparison with patients with the AA genotype (6.90±1.08 vs. 7.48±1.12 mmol/l, p=0.013). Consequently, adjusted ΔFPG was significantly higher in the AG+GG compared to the AA group (1.48±1.51 vs. 1.02±1.33 mmol/l, p=0.022). Similar trend was observed for HbA(1c) levels, but the difference between the genotype groups did not reach the level of statistical significance. Relatively small number of included patients is a limitation of the present study. In conclusion, our results suggest that the magnitude of FPG reduction after 6-month sulphonylurea treatment in patients with type 2 diabetes is related to the variation in CDKAL1.

[Relationship of the CDKAL1 and KCNQ1 gene polymorphisms to the age at diagnosis of type 2 diabetes in the Slovakian population]

BACKGROUND/AIMS

The association of CDKAL1 and KCNQ1 genes with type 2 diabetes mellitus (DM2T) was confirmed by several genome-wide association studies in both Caucasian and Asian populations. For both genes, it is supposed that the risk of DM2T development is related to impaired insulin secretion. Based on assumption that the presence of risk allele might predispose to an earlier onset of DM2T, the aim of the present study was to assess the frequency of risk alleles of CDKAL1 rs7756992 and KCNQ1 rs163184 polymorphisms and to analyze their association with the age at DM2T diagnosis in the Slovakian population.

METHODS

CDKAL1 rs7756992 A/G and KCNQ1 rs163184 G/T polymorphisms were genotyped using asymmetric PCR with subsequent melting curve analysis in a group of 538 patients with DM2T. Anthropometric and laboratory parameters were determined by using standard methods. Since two genes were analysed, the required level for statistical significance was defined as p < 0.025.

RESULTS

Risk homozygotes (CG) for KCNQ1 polymorphism had higher mean age of DM2T diagnosis by 2 years when compared to T-allele carriers (GT + TT) in a recessive model, but the difference did not reach the predefined level of statistical significance. No relationship of CDKAL1 polymorphism to the age at onset of DM2T diagnosis was observed.

CONCLUSIONS

In the present study, no relationship of CDKAL1 and KCNQ1 polymorphisms to the earlier onset of type 2 diabetes was observed.

Effect of gene polymorphisms on lipoprotein levels in patients with dyslipidemia of metabolic syndrome

Dyslipidemia in the metabolic syndrome (MS) is considered to be one of the most important risk factors for atherosclerosis. It is characterized by hypertriglyceridemia, low concentration of plasma HDL-cholesterol, predominance of small dense LDL particles and an increased concentration of plasma apolipoprotein B (apoB). The pathogenesis of this type of dyslipidemia is partially explained, but its genetic background is still unknown. To evaluate the influence of cholesterol ester transfer protein (CETP) TaqIB polymorphism, lipoprotein lipase (LPL) PvuII and HindIII polymorphisms, hepatic lipase (LIPC) G-250A polymorphism and apolipoprotein C-III (APOC3) SstI gene polymorphism on lipid levels in dyslipidemia of the metabolic syndrome, 150 patients with dyslipidemia of metabolic syndrome were included. 96 % of patients had type 2 diabetes. The patients did not take any lipid lowering treatment. The exclusion criterion was the presence of any disease that could affect lipid levels, such as thyroid disorder, liver disease, proteinuria or renal failure. Gene polymorphisms were determined using the polymerase chain reaction and restriction fragment length polymorphisms. The genotype subgroups of patients divided according to examined polymorphisms did not differ in plasma lipid levels with the exception of apoB. The apoB level was significantly higher in patients with S1S1 genotype of APOC3 SstI polymorphism when compared with S1S2 group (1.10+/-0.26 vs. 0.98+/-0.21 g/l, p=0.02). Similarly, patients with H-H- genotype of LPL HindIII polymorphism had significantly higher mean apoB, compared with H+H- and H+H+ group (1.35+/-0.30 vs. 1.10+/-0.26 g/l, p=0.02). In the multiple stepwise linear regression analysis, apoB level seemed to be influenced by APOC3 SstI genotype, which explained 6 % of its variance. The present study has shown that the S1 allele of APOC3 SstI polymorphism and the H- allele of LPL HindIII polymorphism might have a small effect on apoB levels in the Central European Caucasian population with dyslipidemia of metabolic syndrome.

Relationship among urinary albumin excretion rate, lipoprotein lipase PvuII polymorphism and plasma fibrinogen in type 2 diabetic patients

Plasma fibrinogen level represents a strong cardiovascular risk factor and is regulated by an interplay of genetic and environmental factors. Hyperfibrinogenemia frequently occurs in cluster with dyslipidemia within the frame of insulin resistance syndrome (IRS) and type 2 diabetes mellitus. Genetic variants with a pleiotropic effect have been proposed to cause IRS features including hyperfibrinogenemia. We studied the influence of polymorphisms in lipoprotein lipase (LPL) gene, beta-fibrinogen gene (FIBB) and environmental factors on plasma fibrinogen levels in type 2 diabetes patients. 131 type 2 diabetes patients (mean age 62+/-10 years, 33% male) were genotyped for polymorphisms in LPL gene (intron 6 PvuII, intron 8 HindIII) and FIBB gene (-148C/T, -455G/A) by PCR-RFLP method. Fibrinogen was measured by thrombin coagulation method, albuminuria by immunoturbidimetric assay. Polymorphism LPL PvuII showed a gene-dose effect on fibrinogen levels, with the highest fibrinogen in P-P- homozygotes (p = 0.05, analysis of variance). P-carriers (P-P- and P+P- combined) had significantly higher fibrinogen levels compared with P+P+ homozygotes (3.74+/-1.40 g/l vs 3.06+/-1.20 g/l, p=0.03). Other studied polymorphisms were not significantly related to fibrinogen levels. Age- and sex-adjusted fibrinogenemia correlated significantly with albuminuria (r = 0.48, p=0.001), serum uric acid (r = 0.42, p=0.006) and serum creatinine (r = 0.32, p=0.04). Multiple stepwise linear regression identified interaction term of LPL PvuII and albuminuria as an independent predictor of fibrinogen level, explaining 18% of fibrinogen variance. Albuminuria thus appears to be the best predictor of fibrinogen plasma levels in type 2 diabetic patients. Relationship between albuminuria and fibrinogenemia may be modified by the genotype LPL PvuII, which also shows a weak association with plasma fibrinogen level in type 2 diabetes patients.

Increased intracranial arterial resistance in patients with type 2 diabetes mellitus

BACKGROUND

The majority of the studies investigating risk factors for stroke have focused on the atherosclerosis of extracranial carotid arteries. Risk factors for the involvement of intracranial arteries in patients with stroke have not been widely investigated so far. The pulsatility index reflects the vascular resistance of intracranial arteries and could therefore be used as an estimate of the severity of vascular damage.

MAIN PURPOSE

The present study aimed to examine the influence of type 2 diabetes mellitus and some other atherosclerosis risk factors on intracranial vascular resistance in patients with a previous stroke or transient ischemic attack.

METHODS

Transcranial doppler investigations were performed in 103 patients with previous stroke (31 with diagnosis of type 2 diabetes, 72 without diabetes), at least 3 months after stroke occurred. Blood flow velocities of anterior cerebral arteries, middle cerebral arteries, the intracranial part of vertebral arteries and the basilar artery, as well as of the extracranial part of the internal carotid artery were measured, and Gosling's pulsatility index was calculated. The maximal pulsatility index of intracranial arteries was defined to express the most pronounced damage.

RESULTS

Diabetic patients had a significantly higher pulsatility index than non-diabetic patients in all examined intracranial arteries. The maximal pulsatility index was also significantly higher in diabetic patients than in non-diabetic patients (1.24 +/- 0.25 vs. 1.00 +/- 0.23; p < 0.0001). There was no significant difference in the pulsatility index between men and women and between groups of patients with or without hypertension. In the multivariate analysis, the presence of diabetes (p < 0.0001) and the age of patients (p < 0.0001) were the only factors significantly predicting maximal pulsatility index, and this relationship was independent on the presence of hypertension.

CONCLUSIONS

Diabetic patients with previous stroke have a higher pulsatility index than non-diabetic patients with previous strokes, which indicates a higher increase in intracranial arterial resistance and more severe damage to cerebral blood flow in diabetes mellitus.