K. Rašlová

Comet assay in human biomonitoring studies: Reliability, validation, and applications

The comet assay (single‐cell gel electrophoresis), which measures DNA strand breaks at the level of single cells, is very easily applied to human lymphocytes, and therefore lends itself to human biomonitoring studies. For the examination of DNA base oxidation (a specific marker of oxidative damage), the assay is modified by including a stage at which the DNA is incubated with a suitable lesion‐specific endonuclease. Here we report on the reliability and reproducibility of this approach, from the level of comparing results from duplicate gels prepared from the same sample of cells, up to an assessment of the natural intra‐ and interindividual variability in lymphocyte DNA damage measured in groups of normal, healthy human volunteers. We applied the assay in investigations of human disease and occupational exposure of factory workers. Environ. Mol. Mutagen. 30:139–146, 1997.

DNA DAMAGE IN DIABETES : CORRELATION WITH A CLINICAL MARKER

Levels of DNA damage in groups of 10 patients with insulin-dependent diabetes mellitus and 10 matched controls were compared using the comet assay; DNA strand breaks, oxidized pyrimidines (endonuclease III-sensitive sites) and altered purines (sites sensitive to formamidopyrimidine glycosylase) were measured. Mean values of strand breaks and oxidized pyrimidines were significantly higher in diabetics. Strand breaks correlated with body mass index in the diabetic group. A strong correlation was seen between formamidopyrimidine glycosylase-sensitive sites and serum glucose concentrations. When three patients with normal glucose levels were excluded from the statistical analysis, the mean value of formamidopyrimidine glycosylase-sensitive sites was very significantly elevated compared with normal. DNA damage in lymphocytes is thus a useful marker of oxidative stress, and in particular formamidopyrimidine glycosylase-sensitive sites seem to represent changes specifically related to hyperglycemia.

Glutathione S-transferase polymorphisms influence the level of oxidative DNA damage and antioxidant protection in humans

Glutathione S-transferase genotypes GSTT1, GSTM1, GSTP1 were characterised in 155 middle-aged men and compared with parameters of oxidative stress at the level of DNA and lipids, with antioxidant enzymes, and with plasma antioxidants in smokers and non-smokers. Smokers had on average significantly lower levels of Vitamin C, beta-carotene and beta-cryptoxanthin and higher amounts of oxidised purines and pyrimidines in lymphocyte DNA. The GSTM1 null genotype was associated with elevated glutathione as well as with higher Vitamin C concentration in plasma. Vitamin C was higher in GSTT1+ compared with GSTT1 null--as was glucose-6-phosphate dehydrogenase activity. The homozygous GSTP1 a/a genotype was associated with significantly higher levels of GST activity measured in lymphocytes, in comparison with the b/b genotype. Using multifactorial statistical analysis we found significant associations between smoking, GSTP1 genotype, plasma Vitamin C, and purine base damage in lymphocyte DNA. The difference in Vitamin C plasma levels between smokers and non-smokers was seen only with the GSTP1 b/b genotype. This group accounted also for most of the increase in purine oxidation in smokers. In contrast, the link between smoking and oxidised pyrimidines in DNA was seen only in the GSTT1 null group. It seems that polymorphisms in the phase II metabolising enzyme glutathione S-transferase may be important determinants of commonly measured biomarkers.

Insulin Detemir Results in Less Weight Gain than NPH Insulin When Used in Basal-Bolus Therapy for Type 2 Diabetes Mellitus, and this Advantage Increases with Baseline Body Mass Index

AbstractObjective: Weight gain during insulin therapy can be a challenging problem in already overweight type 2 diabetes mellitus patients, affecting treatment compliance and long-term prognosis. The analogue insulin detemir has been reported to have a weight-sparing effect compared with other basal insulins. This pooled analysis investigated whether this potential advantage is related to body mass index (BMI) when insulin detemir is used as the basal component of basal-bolus therapy. Methods: Data were pooled from two randomised, parallel group trials of 22 and 24 weeks’ duration, in which 900 insulin-treated patients with type 2 diabetes mellitus had their treatment intensified to basal-bolus therapy. Patients received once- or twice-daily insulin detemir or neutral protamine Hagedorn (NPH) insulin in conjunction with insulin aspart or human soluble insulin at mealtimes. Results: Patients treated with insulin detemir had minimal weight gain (mean <1kg), regardless of their BMI at entry (estimated slope −0.032), whereas, in patients treated with NPH insulin, weight gain increased as baseline BMI increased (estimated slope 0.075, p = 0.025). Indeed, NPH insulin-treated patients with the largest BMI (>35 kg/m2) gained the most weight (mean of ∼2.4kg). In contrast, insulin detemir-treated patients with a BMI >35 kg/m2 lost weight (mean of ∼−0.5kg). Glycaemic control was similar with the two treatments. Conclusion: Insulin detemir may provide a clinical advantage in terms of reduced weight gain in the treatment of overweight patients with type 2 diabetes.

Lipid levels and their genetic regulation in patients with familial hypercholesterolemia and familial defective apolipoprotein B-100: the MEDPED Slovakia Project.

We examined, from a cohort of 165 families, 529 individuals for familial hypercholesterolemia (FH). Utilising clinical criteria for diagnosis, we identified 122 patients (n=41 families) as having FH. With PCR testing, 31 individuals (n=12 families) were found to have familial defective Apo B-100 (FDB). From the cohort, 102 normolipidemic (NL) individuals served as a control group. Patients with FH had the highest levels of total cholesterol (TC), LDL-cholesterol (LDL-C) and apolipoprotein B (Apo B), followed by FDB patients and the normolipidemic relatives had the lowest levels (P<0.0001 for all parameters). We did not find any effect of Apo E genotypes on lipid levels in the NL or FH group. Therefore, other genetic and/or environmental factors may be responsible for the diversity in the clinical expression in these populations.

A Combination of CD28 (rs1980422) and IRF5 (rs10488631) Polymorphisms Is Associated with Seropositivity in Rheumatoid Arthritis: A Case Control Study

Introduction The aim of the study was to analyse genetic architecture of RA by utilizing multiparametric statistical methods such as linear discriminant analysis (LDA) and redundancy analysis (RDA). Methods A total of 1393 volunteers, 499 patients with RA and 894 healthy controls were included in the study. The presence of shared epitope (SE) in HLA-DRB1 and 11 SNPs (PTPN22 C/T (rs2476601), STAT4 G/T (rs7574865), CTLA4 A/G (rs3087243), TRAF1/C5 A/G (rs3761847), IRF5 T/C (rs10488631), TNFAIP3 C/T (rs5029937), AFF3 A/T (rs11676922), PADI4 C/T (rs2240340), CD28 T/C (rs1980422), CSK G/A (rs34933034) and FCGR3A A/C (rs396991), rheumatoid factor (RF), anti–citrullinated protein antibodies (ACPA) and clinical status was analysed using the LDA and RDA. Results HLA-DRB1, PTPN22, STAT4, IRF5 and PADI4 significantly discriminated between RA patients and healthy controls in LDA. The correlation between RA diagnosis and the explanatory variables in the model was 0.328 (Trace = 0.107; F = 13.715; P = 0.0002). The risk variants of IRF5 and CD28 genes were found to be common determinants for seropositivity in RDA, while positivity of RF alone was associated with the CTLA4 risk variant in heterozygous form. The correlation between serologic status and genetic determinants on the 1st ordinal axis was 0.468, and 0.145 on the 2nd one (Trace = 0.179; F = 6.135; P = 0.001). The risk alleles in AFF3 gene together with the presence of ACPA were associated with higher clinical severity of RA. Conclusions The association among multiple risk variants related to T cell receptor signalling with seropositivity may play an important role in distinct clinical phenotypes of RA. Our study demonstrates that multiparametric analyses represent a powerful tool for investigation of mutual relationships of potential risk factors in complex diseases such as RA.

Genetic determinants of quantitative traits associated with cardiovascular disease risk

Established risk factors for cardiovascular diseases (CVD) may be moderated by genetic variants. In 2403 unrelated individuals from general practice (mean age 40.5 years), we evaluated the influence of 15 variants in 12 candidate genes on quantitative traits (QT) associated with CVD (body mass index, abdominal obesity, glucose, serum lipids, and blood pressure). Prior to multiple testing correction, univariate analysis associated APOE rs429358, rs7412 and ATG16L1 rs2241880 variants with serum lipid levels, while LEPR rs1137100 and ATG16L1 rs2241880 variants were linked to obesity related QTs. After taking into account confounding factors and correcting for multiple comparisons only APOE rs429358 and rs7412 variants remained significantly associated with risk of dyslipidemia. APOE rs429358 variant almost tripled the risk in homozygous subjects (OR = 2.97; 95% CI 1.09-8.10, p < 0.03) and had a lesser but still highly significant association also in heterozygous individuals (OR = 1.67; 95% CI 1.24-2.10; p < 0.001). Associations with hypertension, diabetes mellitus, and metabolic syndrome were not significant after Bonferroni correction. The influence of genetic variation is more evident in dyslipidemia than in other analyzed QTs. These results may contribute to strategic research aimed at including genetic variation in the set of data required to identify subjects at high risk of CVD.

Contribution of Genetic Factors to Lower DHEAS in Patients with Rheumatoid Arthritis

AbstractObjective Lower production of adrenal androgens has been confirmed in females with rheumatoid arthritis (RA); however, the mechanisms of this finding are not completely understood. The aim of our study was to assess the contribution of genetic factors associated with variability of dehydroepiandrosterone sulfate (DHEAS) levels to lower DHEAS in female RA patients.Methods448 RA and 648 healthy controls were genotyped for single-nucleotide polymorphisms (SNPs) in genes ZKSCAN5 (rs11761528), SULT2A1 (rs2637125), HHEX (rs2497306), and ARPC1A (rs740160). Serum DHEAS concentrations were measured in 112 RA patients and 91 healthy women.ResultsThe allele frequencies in DHEAS-related loci were similar in RA and controls. RA patients had significantly lower serum DHEAS concentrations compared to healthy women. The cumulative number of alleles associated with lower DHEAS within genes ZKSCAN5, SULT2A1, HHEX, and ARPC1A present in each individual negatively correlated with DHEAS levels in RA patients, but not in controls. Linear regression analysis showed significant effect of polymorphisms in genes ZKSCAN5 and ARPC1A on serum DHEAS levels in female RA patients but not in the control group.ConclusionOur findings suggest that complex interactions exist between genotype and adrenal androgen hypofunction in RA.

Real-life LDL-C treatment goals achievement in patients with heterozygous familial hypercholesterolemia in the Czech Republic and Slovakia: Results of the PLANET registry

BACKGROUND AND AIMS Despite the high prevalence of familial hypercholesterolemia (FH) and available effective lipid-lowering therapy, most of the individuals with this disorder remain undiagnosed and undertreated. The aim of the PLANET registry was to assess the real-life attainment of low-density lipoprotein cholesterol (LDL-C) therapeutic target level in patients with heterozygous FH, to characterize prescribed lipid-lowering therapy with assessment of its efficiency according to the attainment of the target LDL-C level, and to characterize cardiovascular events observed in this patient population again in relation to LDL-C target level attainment. METHODS PLANET registry was designed as a non-interventional, retrospective, cross-sectional, multicentre disease registry for adult patients with heterozygous FH in the Czech Republic and Slovakia. RESULTS Overall, 1755 patients were enrolled at 32 sites specialized in FH treatment. 15.4% of patients attained the target LDL-C value. The proportion of patients with LDL-C goal achievement increased to 17.3% in the subgroup of patients receiving high-intensity statin therapy (54.6% of study population). Out of 55 patients receiving inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9), 61.8% reached the LDL-C treatment goal. Of all cardiovascular events reported, 14.0% occurred in patients attaining the LDL-C goal, while it was 86.0% in the not-at-target group. It was documented (p=0.004) that the longer is the patient in care at the specialized FH centre, the higher is the probability that he/she will attain the target LDL-C level. CONCLUSIONS Although target LDL-C level attainment remains relatively low, the likelihood of LDL-C goal attainment increases with duration of specialized care.

Treatment pattern of familial hypercholesterolemia in slovakia: Targets, treatment and obstacles in common practice

Background and aims: Maximal doses of potent statins are the cornerstone of treatment of familial hypercholesterolemia (FH). Despite this, a substantial proportion of FH patients are either under-treated or not treated at all. The aim of this work was to evaluate, in a retrospective study, the treatment of FH patients, the proportion of FH patients reaching low-density lipoprotein cholesterol (LDL-C) goals, and reasons for not reaching LDL-C goals, in 8 lipid clinics in Slovakia dealing with FH patients. Methods: 201 heterozygous FH patients (50.8± 14.9 years, 55% females) who attended the lipid clinics at least three times were included in the study. Results: At the first visit, 31.3% of patients were treated with statins and the most common dose was 20mg of atorvastatin, rosuvastatin and simvastatin. At the third visit, 78.1% of patients were treated with statins and 24.4% with ezetimibe. The majority of patients were treated with atorvastatin (75.8%) and rosuvastatin (18.5%) and 31.3% of all patients were treated with atorvastatin 80mg or rosuvastatin 40mg with/without ezetimibe. However, only 11.9% of patients with the LDL-C goal level <2.5mmol/l and 6.9% with the goal <1.8mmol/l reached the level. Reasons for not reaching the goal levels were evaluated by physicians in each patient. Insufficient LDL-C lowering effect of treatment, side-effects of therapy and non-compliance of patients were responsible for 46%, 18% and 30% of cases, respectively. Conclusions: Referral of FH patients to lipid clinics in Slovakia leads to improvement in the treatment; however, almost 22% of the patients are still without statin treatment and the majority of patients do not reach the LDL-C goal level.