Monitoring of plasma circulating donor DNA reflects cardiac graft injury: Report of two cases

The current standard for graft rejection surveillance is endomyocardial biopsy (EMB), an invasive procedure with rare but potentially serious complications. Detection of circulating donor-derived cell-free DNA (ddcfDNA) is an option for noninvasive monitoring of graft injury and rejection. A 63-year-old man and a 65-year-old woman were monitored by EMB for allograft rejection. A total of 48 single-nucleotide polymorphisms with a minor allele frequency range of 0.4-0.5 were screened to distinguish donor and recipient DNA based on homozygosity, and digital droplet PCR was used to analyze ddcfDNA concentrations. Both subjects suffered rejection within the first 6 months after transplantation. The maximal ddcfDNA level of 270 copies (cp)/ml during EMB-confirmed acute cellular rejection (ACR; mild grade 1R/2, patient 1), and the maximal concentration of 1,846 cp/ml in the case of EMB-confirmed antibody-mediated rejection (AMR; grade 1+; patient 2), was detected. Individual monitoring of ddcfDNA dynamics from the 1st to the 6th month posttransplant reflected cardiac graft injury in patients suffering ACR or AMR, meaning that ddcfDNA may serve as a noninvasive biomarker.

Long-Term LDL-Apheresis Treatment and Dynamics of Circulating miRNAs in Patients with Severe Familial Hypercholesterolemia

Lipoprotein apheresis (LA) is a therapeutic option for patients with severe hypercholesterolemia who have persistently elevated LDL-C levels despite attempts at drug therapy. MicroRNAs (miRNAs), important posttranscriptional gene regulators, are involved in the pathogenesis of atherosclerosis. Our study aimed to monitor the dynamics of twenty preselected circulating miRNAs in patients under long-term apheresis treatment. Plasma samples from 12 FH patients (men = 50%, age = 55.3 ± 12.2 years; mean LA overall treatment time = 13.1 ± 7.8 years) were collected before each apheresis therapy every sixth month over the course of four years of treatment. Eight complete follow-up (FU) samples were measured in each patient. Dynamic changes in the relative quantity of 6 miRNAs (miR-92a, miR-21, miR-126, miR-122, miR-26a, and miR-185; all p < 0.04) during FU were identified. Overall apheresis treatment time influenced circulating miR-146a levels (p < 0.04). In LDLR mutation homozygotes (N = 5), compared to heterozygotes (N = 7), we found higher plasma levels of miR-181, miR-126, miR-155, and miR-92a (all p < 0.03). Treatment with PCSK9 inhibitors (N = 6) affected the plasma levels of 7 miRNAs (miR-126, miR-122, miR-26a, miR-155, miR-125a, miR-92a, and miR-27a; all p < 0.04). Long-term monitoring has shown that LA in patients with severe familial hypercholesterolemia influences plasma circulating miRNAs involved in endothelial dysfunction, cholesterol homeostasis, inflammation, and plaque development. The longer the treatment using LA, the better the miRNA milieu depicting the potential cardiovascular risk.

Macrovascular and microvacular changes in diabetes mellitus type 1 are modified by the gene for connexin 37 in men but not in women

Introduction

Diabetes mellitus type 1 (DMT1) is a strong risk factor for macrovascular and microvascular disease. These vascular pathologies can be strongly modified by genetic factors. One of intensively investigated candidate genes is the gene for connexin37 (Cx37) (C1019&gt;T (Pro319&gt;Ser). The role of this gene in cardiovascular disease and diabetes mellitus had been already described in several different populations, but not in patients with DMT1.

Purpose

To determine whether the presence of macrovascular and microvascular changes is modified by Cx37 gene polymorphism in middle aged men and women diagnosed with DMT1 of similar age and with similar duration of DMT1.

Methods

In 253 men (mean age 43.0±14.5 years; mean duration of diabetes 22.6±14.0 years) and 245 women (mean age 43.9±12.9 years; mean duration of diabetes 21.3±10.5 years) macrovascular disease was measured by duplex B-Mode ultrasound and classified as Belcaro score (1–4) in carotid and femoral arteries. Microvascular disease was assessed by the presence of retinopathy, nephropathy, neuropathy and diabetic foot. Cx37 gene polymorphism was established by PCR.

Results

In men, in CC homozygotes we observed more advanced macrovascular changes in carotid arteries (Belcaro score more than 2) than in CT heterozygotes/TT homozygotes (7.5 vs. 15.2%; p=0.031). No significant differences were found in changes of carotid arteries in women and in changes of femoral arteries both in men and women. Regarding microvascular changes, in men, in CC homozygotes, the diabetic foot was diagnosed more frequently than in CT heterozygotes/TT homozygotes (7.4 vs. 16.1%; p=0.046). No significant differences were found in women and in other types of microvascular disease both in men and women.

Conclusion

These results indicate that macrovascular and microvascular changes in DMT1 can be modified by Cx37 gene polymorphism in men, but not in women.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Ministry of Health of the Czech Republic, grant No. NU20-01-00083 and by Ministry of Health of the Czech Republic under its conceptual development of the research organization program (Institute for Clinical and Experimental Medicine–IKEM, IN 00023001. All rights reserved.

Genetic risk score is associated with T2DM and diabetes complications risks

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a prototypical complex disease with polygenic architecture playing an important role in determining susceptibility to develop the disease (and its complications) in subjects exposed to modifiable lifestyle factors. A current challenge is to quantify the degree of the individual's genetic risk using genetic risk scores (GRS) capturing the results of genome-wide association studies while incorporating possible ethnicity- or population-specific differences.

METHODS

This study included three groups of T2DM (T2DM-I, N=1,032; T2DM-II, N=353; and T2DM-III, N=399) patients and 2,481 diabetes-free subjects. The status of the microvascular and macrovascular diabetes complications were known for the T2DM-I patients. Overall, 21 single nucleotide polymorphisms (SNPs) were analyzed, and selected subsets were used to determine the GRS (both weighted - wGRS and unweighted - uGRS) for T2DM risk predictions (6 SNPs) and for predicting the risks of complications (7 SNPs).

RESULTS

The strongest T2DM markers (P<0.0001) were within the genes for TCF7L2 (transcription factor 7-like 2), FTO (fat mass and obesity associated protein) and ARAP1 (ankyrin repeat and PH domain 1). The T2DM-I subjects with uGRS values greater (Odds Ratio, 95% Confidence Interval) than six had at least twice (2.00, 1.72-2.32) the risk of T2DM development (P<0.0001), and these results were confirmed in the independent groups (T2DM-II 1.82, 1.45-2.27; T2DM-III 2.63, 2.11-3.27). The wGRS (>0.6) further improved (P<0.000001) the risk estimations for all three T2DM groups. The uGRS was also a significant predictor of neuropathy (P<0.0001), nephropathy (P<0.005) and leg ischemia (P<0.0005).

CONCLUSIONS

If carefully selected and specified, GRS, both weighted and unweighted, could be significant predictors of T2DM development, as well as the diabetes complications development.

Cholesterol and the risk of acute coronary syndrome. Mendelian randomisation in the Czech population

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health, Czech Republic

Introduction

Increased plasma cholesterol levels are considered as a risk factor for the development of cardiovascular diseases, including acute coronary syndrome (ACS). However, observational studies in recent years have often found no increased LDL-cholesterol values in ACS patients compared to controls. Final cholesterol levels are largely modified by genetic factors, so they can be used to demonstrate (based on Mendelian randomization) whether the link between plasma cholesterol and MI risk is still present.

Methods

In our study, we analysed LDL-R (rs6511720), CILP2/PBX4 (rs16996148), APOB (rs693) and SORT-1 (rs646776) variants in a total of 939 patients with ACS and 1,191 healthy controls (post-MONICA study). Only men aged 18-65 years were included in the study.

Results

Patients with ACS had significantly lower total cholesterol levels than controls (4.8 ± 1.1 vs. 5.7 ± 1.1 mmol / L; P &lt;0.001). Total and LDL-cholesterol were not higher in patients even after adjusting for age, BMI and dyslipidemic treatment. We confirmed a significant effect of all analysed variants on LDL-cholesterol levels (all P &lt;0.01). None of the four analysed variants significantly affected the risk of MI (P values between 0.10 and 0.58). Individuals with at least seven cholesterol-raising alleles had a slightly increased risk of ACS compared to others (OR, 95% CI; 1.26, 1.06-1.51; P = 0.01).

Conclusion

Variants within the genes for LDL-R, CILP2 / PBX4, APOB and SORT-1 are significant genetic determinants of LDL-cholesterol levels in the population of Czech men. After a population-wide reduction in cholesterol levels, these levels no longer seem to be a serious problem in determining ACS, and interventions to reduce other types of risk should be given more attention.

ACE I/D polymorphism in Czech first-wave SARS-CoV-2-positive survivors

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread from China in 2019/2020 to all continents. Significant geographical and ethnic differences were described, and host genetic background seems to be important for the resistance to and mortality of COVID-19. Angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism (rs4646994) is one of the candidates with the potential to affect infection symptoms and mortality.

METHODS

In our study, we successfully genotyped 408 SARS-CoV-2-positive COVID-19 survivors (163 asymptomatic and 245 symptomatic) and compared them with a population-based DNA bank of 2,559 subjects.

RESULTS

The frequency of ACE I/I homozygotes was significantly increased in COVID-19 patients compared with that in controls (26.2% vs. 21.2%; P = 0.02; OR [95% CI] = 1.55 [1.17-2.05]. Importantly, however, the difference was driven just by the symptomatic subjects (29.0% vs. 21.2% of the I/I homozygotes; P = 0.002; OR [95% CI] = 1.78 [1.22-2.60]). The genotype distribution of the ACE genotypes was almost identical in population controls and asymptomatic SARS-CoV-2-positive patients (P = 0.76).

CONCLUSIONS

We conclude that ACE I/D polymorphism could have the potential to predict the severity of COVID-19, with I/I homozygotes being at increased risk of symptomatic COVID-19.

An Integrative Study of Aortic mRNA/miRNA Longitudinal Changes in Long-Term LVAD Support

Studying the long-term impact of continuous-flow left ventricular assist device (CF-LVAD) offers an opportunity for a complex understanding of the pathophysiology of vascular changes in aortic tissue in response to a nonphysiological blood flow pattern. Our study aimed to analyze aortic mRNA/miRNA expression changes in response to long-term LVAD support. Paired aortic samples obtained at the time of LVAD implantation and at the time of heart transplantation were examined for mRNA/miRNA profiling. The number of differentially expressed genes (Pcorr < 0.05) shared between samples before and after LVAD support was 277. The whole miRNome profile revealed 69 differentially expressed miRNAs (Pcorr < 0.05). Gene ontology (GO) analysis identified that LVAD predominantly influenced genes involved in the extracellular matrix and collagen fibril organization. Integrated mRNA/miRNA analysis revealed that potential targets of miRNAs dysregulated in explanted samples are mainly involved in GO biological process terms related to dendritic spine organization, neuron projection organization, and cell junction assembly and organization. We found differentially expressed genes participating in vascular tissue engineering as a consequence of LVAD duration. Changes in aortic miRNA levels demonstrated an effect on molecular processes involved in angiogenesis.

The effect of long-term left ventricular assist device support on flow-sensitive plasma microRNA levels

BACKGROUND

Implantation of current generation left ventricular assist devices (LVADs) in the treatment of end-stage heart failure (HF), not only improves HF symptoms and end-organ perfusion, but also leads to cellular and molecular responses, presumably in response to the continuous flow generated by these devices. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression in multiple biological processes, including the pathogenesis of HF. In our study, we examined the influence of long-term LVAD support on changes in flow-sensitive miRNAs in plasma.

MATERIALS AND METHODS

Blood samples from patients with end-stage heart failure (N = 33; age = 55.7 ± 11.6 years) were collected before LVAD implantation and 3, 6, 9, and 12 months after implantation. Plasma levels of the flow-sensitive miRNAs; miR-10a, miR-10b, miR-146a, miR-146b, miR-663a, miR-663b, miR-21, miR-155, and miR-126 were measured using quantitative PCR.

RESULTS

Increasing quantities of miR-126 (P < 0.03) and miR-146a (P < 0.02) was observed at each follow-up visit after LVAD implantation. A positive association between miR-155 and Belcaro score (P < 0.04) and an inverse correlation between miR-126 and endothelial function, measured as the reactive hyperemia index (P < 0.05), was observed.

CONCLUSIONS

Our observations suggest that after LVAD implantation, low pulsatile flow up-regulates plasma levels of circulating flow-sensitive miRNAs, contributing to endothelial dysfunction and vascular remodeling.

Genetics of Cardiovascular Disease: How Far Are We from Personalized CVD Risk Prediction and Management?

Despite the rapid progress in diagnosis and treatment of cardiovascular disease (CVD), this disease remains a major cause of mortality and morbidity. Recent progress over the last two decades in the field of molecular genetics, especially with new tools such as genome-wide association studies, has helped to identify new genes and their variants, which can be used for calculations of risk, prediction of treatment efficacy, or detection of subjects prone to drug side effects. Although the use of genetic risk scores further improves CVD prediction, the significance is not unambiguous, and some subjects at risk remain undetected. Further research directions should focus on the “second level” of genetic information, namely, regulatory molecules (miRNAs) and epigenetic changes, predominantly DNA methylation and gene-environment interactions.

CCR5Delta32 deletion as a protective factor in Czech first-wave COVID-19 subjects

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease (COVID-19), has spread widely around the globe. Significant inter-individual differences have been observed during the course of the infection, which suggests that genetic susceptibility may be a contributing factor. CC chemokine receptor 5 (CCR5), which acts as a co-receptor for the entry of HIV-1 into cells, is promising candidate whose can have an influence on SARS-CoV-2 infection. A genetic mutation known as CCR5Delta32, consisting of a 32-nucleotide deletion, encodes a truncated protein that protects homozygous carriers of the deletion from HIV-1 infection. Similarly, inhibition of CCR5 seems to be protective against COVID-19. In our study, we successfully genotyped 416 first-wave SARS-CoV-2-positive infection survivors (164 asymptomatic and 252 symptomatic) for CCR5?32, comparing them with a population based sample of 2,404 subjects. We found the highest number (P=0.03) of CCR5Delta32 carriers in SARS-CoV-2-positive/COVID-19-asympto-matic subjects (23.8 %) and the lowest number in SARS-CoV-2-positive/COVID-19-symptomatic patients (16.7 %), with frequency in the control population in the middle (21.0 %). We conclude that the CCR5?32 I/D polymorphism may have the potential to predict the severity of SARS-CoV-2 infection.

Prediction of long-term prognosis of age-related macular degeneration treated by hemorheologic therapy using baseline laboratory indicators - Experimental-clinical model

BACKGROUND + OBJECTIVE:Age-related macular degeneration (AMD) is the most common cause of practical blindness in people over 60 years of age in industrialised countries. We formulated a hypothesis that a group of initial laboratory parameters would be suitable for prediction of prognosis of AMD, allowing for individual modifications in treatment intensity.

PATIENTS AND METHODS

66 patients with dry form of AMD were treated using rheohaemapheresis with an individual follow-up period of more than 5 years. The patients' initial laboratory data was split in two subgroups based on treatment success and analysed using discriminant analysis (analysis of the linear and quadratic models using the automated and interactive step-wise approach) by means of the Systat 13 software.

RESULTS

Prediction of prognosis based on the initial laboratory parameters was correct in 79% of unsuccessfully treated patients, allowing for early detection of high-risk patients. With the use of a quadratic model, the prediction was correct in 100% of unsuccessfully treated patients and in 75% of successfully treated patients.

CONCLUSION

Implementation of discriminant analysis is a promising method for prediction of prognosis, especially when the patient is at risk of AMD progression, which allows for early and more intensive monitoring and treatment.

The Gene Score for Predicting Hypertriglyceridemia: New Insights from a Czech Case-Control Study

BACKGROUND

Plasma triglyceride (TG) values are significant predictors of cardiovascular and total mortality. The plasma levels of TGs have an important genetic background. We analyzed whether 32 single nucleotide polymorphisms (SNPs) identified in genome-wide association studies are discriminators of hypertriglyceridemia (HTG) in the Czech population.

OBJECTIVES

The objective of this study was to replicate and test the original findings in an independent study and to re-analyze the gene score leading to HTG.

METHODS

In total, we analyzed 32 SNPs in 209 patients with plasma TG levels over 10 mmol/L (HTG group) and compared them in a case-control design with 524 treatment-naïve controls (normotriglyceridemic [NTG] group) with plasma TG values below 1.8 mmol/L.

RESULTS

Sixteen SNPs were significantly associated with an increased risk of HTG development, with odds ratios (ORs) (95% confidence interval [CI]) varying from 1.40 (1.01-1.95) to 4.69 (3.29-6.68) (rs964184 within the APOA5 gene). Both unweighted (sum of the risk alleles) and weighted gene scores (WGS) (log of the achieved ORs per individual genotype) were calculated, and both gene scores were significantly different between groups. The mean score of the risk alleles was significantly increased in the HTG group compared to the NTG group (18.5 ± 2.5 vs. 15.7 ± 2.3, respectively; P < 0.00001). Subjects with a WGS over 9 were significantly more common in the HTG group (44.5%) than in the NTG group, in which such a high score was observed in only 4.7% of subjects (OR 16.3, 95% CI 10.0-36.7; P < 0.0000001).

CONCLUSIONS

An increased number of risk genetic variants, calculated both in a weighted or unweighted manner, significantly discriminates between the subjects with HTG and controls. Population-specific sets of SNPs included into the gene score seem to yield better discrimination power.

Leukocyte telomere length is not affected by long-term occupational exposure to nano metal oxides

The aim of this study was to ascertain whether long-term occupational exposure to nanoparticles would affect relative leukocyte telomere length (LrTL). We analysed occupational exposure to size-resolved aerosol particles, with special emphasis on nanoparticles at two workshops: i/ the production of nanocomposites containing metal oxides; ii/ laboratory to test experimental exposure of nano-CuO to rodents. Thirty five exposed researchers (age 39.5 ± 12.6 yr; exposure duration 6.0 ± 3.7 yr) and 43 controls (40.4 ± 10.5 yr) were examined. LrTL did not significantly (p=0.14) differ between the exposed researchers (0.92 ± 0.13) and controls (0.86 ± 0.15). In addition, no significant correlation (r=-0.22, p=0.22) was detected between the duration of occupational exposure and LrTL. The results remained non-significant after multiple adjustments for age, sex and smoking status. Our pilot results suggest that relative leukocyte telomere length is not affected by occupational exposure to nanoparticles.

Association between aortic telomere length and cardiac post-transplant allograft function

BACKGROUND

In patients having undergone orthotopic heart transplantation, a number of complications exist that are known to be connected to both telomerase activity and telomere length. The aim of this study was to determine how telomere length in aortic DNA correlates with the subsequent post-transplantation development of the patients.

MATERIALS AND METHODS

Between 2005 and 2015, we collected aortic samples from 376 heart recipients (age 50.8 ± 11.8 years) and 383 donors (age 38.6 ± 12.2 years). Relative telomere length in aortic tissue DNA was determined using quantitative PCR.

RESULTS

Shorter telomere length was detected in heart allograft recipients compared to donors (P < 0.0001). Patients suffering acute cellular rejection had significantly shorter telomere length (P < 0.01) than patients without rejection. Shorter telomere length was observed in patients with implanted mechanical circulatory support before heart transplantation (P < 0.03), as well as in subjects with cardiac allograft vasculopathy (P < 0.05). Overall survival time after heart transplantation was associated with shorter donor telomeres (P < 0.004).

CONCLUSIONS

Telomere length differed between donors and recipients independent of the sex and age of the patients. Our findings suggest a potential new linkage between the aortic telomere length of recipients and post-heart transplant complications. Further studies focusing on epigenetic modifications and gene regulation involved in telomere maintenance in transplanted patients should verify our results.

Strong Association between APOA5 Gene Polymorphisms and Hypertriglyceridaemic Episodes

Plasma triglyceride (TG) levels represent a significant risk factor of cardiovascular and total mortality. Concentrations of TG in the plasma depend, to a large extent, on the genetic background, and the apolipoprotein A5 (APOA5) gene seems to be one of the most powerful players in the plasma TG metabolism regulation. In total, we analysed three tagging APOA5 (rs964184 rs662799, rs3135506) SNPs in 209 patients with plasma TG levels over 10 mmol/l (HTG) on at least one occasion and in 379 treatment-naïve controls (NTG) with plasma TG values within the normal range. Minor alleles of all three analysed APOA5 polymorphisms significantly (all P < 0.0001) increased the risk of hypertriglyceridaemia. The most significant association (P < 0.0000001) was observed for the rs964184 polymorphism, where the minor GG homozygotes had the odds ratio (OR, 95% CI) for hypertriglyceridaemia development 21.30 (8.09-56.07, P < 0.000001) in comparison with the major CC allele homozygotes. Carriers of at least one minor allele at rs3135506 had OR (95% CI) 4.19 (2.75-6.40); (P < 0.000005) for HTG development and similarly, carriers of a minor allele at rs662799 had OR (95% CI) 3.07 (2.00-4.72) (P < 0.0001). The cumulative presence of risk alleles (unweighted gene score) significantly differed between patients with episodes of high TG and controls at P < 0.0000001. There were 73 % of subjects without any of the risk alleles among the controls and 46 % in the patients. In contrast, the controls just included 3 % of subjects with score 3 and more in comparison with 18 % in HTG patients. We conclude that common APOA5 variants are very important genetic determinants of episodic hypertriglyceridaemia in the Czech population with a high potential to be applied in personalized medicine.

The FTO variant is associated with chronic complications of diabetes mellitus in Czech population

BACKGROUND

Genome-wide association studies have resulted in the identification of the FTO gene as an important genetic determinant of diabetes mellitus. The aim of this study was to confirm the role of this gene in the development of DM in the Czech-Slavonic population and to analyse whether this gene is associated with common DM complications.

METHODS

Two groups of patients (814 with T1DM and 848 with T2DM) and a group of healthy controls (2339 individuals) - both of Czech origin - were genotyped for the FTO rs17817449 SNP. ANOVA and logistic regression were used for the statistical evaluations.

RESULTS

The frequency of the GG genotype was significantly higher in T2DM (25.4% vs. 16.7%, P<0.0005) but not in T1DM patients (19.3% vs. 16.7%, P=0.20) than in controls. The increased risk of development of diabetic nephropathy was observed both for T1DM patients (GG vs. TT homozygotes, P<0.01) and T2DM patients (G carriers vs. TT homozygotes, P<0.05). FTO genotype predicted the development of diabetic neuropathy (GG vs. TT comparison; P<0.01) in the T2DM patients only. No association between FTO genotype and development of retinopathy was detected. All presented values are after adjustment for age, sex, BMI and duration of diabetes.

CONCLUSIONS

We confirm the association between the FTO rs17817449 SNP and susceptibility to T2DM in the Czech-Slavonic population. The same variant is associated with a spectrum of chronic complications in both types of diabetes.

Analysis of circulating miRNAs in patients with familial hypercholesterolaemia treated by LDL/Lp(a) apheresis

BACKGROUND

LDL/Lp(a) apheresis therapy is a well-established method of aggressively lowering LDL and Lp(a). Recently, miRNAs have been discussed as markers of vascular status including atherosclerosis. MiRNAs inhibit post-transcriptional processes through RNA duplex formation resulting in gene silencing or regulation of gene expression.

MATERIALS AND METHODS

We measured a profile of 175 plasma-circulating miRNAs using pre-defined Serum/Plasma Focus Human microRNA PCR Panels in pooled samples of 11 subjects with familial hypercholesterolaemia under long-term apheresis treatment. Subsequently we analysed expressions of ten pre-selected miRNAs potentially involved in lipid homeostasis in the same group of subjects. We compared plasma-circulating miRNA levels isolated from peripheral blood collected immediately before and after apheresis.

RESULTS

The greatest differences in plasma levels were found in miR-451a, miR-16, miR-19a/b, miR-223 and miR-185. In subsequent individual miRNA assay we detected a significant increase in miR-33b levels after apheresis (P < 0.05). Additionally, correlations between plasma lipids and miR-33a (P < 0.04) and miR-122 (P < 0.01) have been determined. Moreover, miR-122 levels in LDLR homozygotes were higher compared to heterozygotes after, but not before, apheresis treatment (P < 0.04).

CONCLUSIONS

LDL/Lp(a) apheresis has an impact on miRNAs associated with lipid homeostasis and vascular status.

Strong gender-specific additive effects of the NYD-SP18 and FTO variants on BMI values

The role of the FTO gene in obesity development is well established in populations around the world. The NYD-SP18 variant has been suggested to have a similar effect on BMI, but the role of this gene in determining BMI has not yet been verified. The objective of our study was to confirm the association between NYD-SP18 rs6971019 SNP and BMI in the Slavic population and to analyze i) the gender-specific effects of NYD-SP18 on BMI and ii) the simultaneous effect of FTO rs17817449 and NYD-SP18 on BMI. We analyzed a sample of a large adult population based on the post-MONICA study (1,191 males and 1,368 females). Individuals were analyzed three times over 9 years. NYD-SP18 rs6971019 SNP is related to BMI in males (2000/1 GG 28.3+/-3.7 kg/m(2) vs. +A 27.5+/-3.7 kg/m(2) P<0.0005; in other examinations P<0.05 and <0.005), but not in females (all P values over 0.48 in all three examinations). Further analysis revealed the significant additive effect (but not the interaction) of FTO and NYD-SP18 SNPs on BMI in males (all P<0.01). These results suggest that association between NYD-SP18 rs6971019 SNP and BMI may be restricted to males. Furthermore, variants within NYD-SP18 and FTO genes revealed a significant additive effect on BMI values in males.

Comparison of the relative telomere length measured in leukocytes and eleven different human tissues

The relative length of telomeres measured in peripheral blood leukocytes is a commonly used system marker for biological aging and can also be used as a biomarker of cardiovascular aging. However, to what extent the telomere length in peripheral leukocytes reflects telomere length in different organ tissues is still unclear. Therefore, we have measured relative telomere length (rTL) in twelve different human tissues (peripheral blood leukocytes, liver, kidney, heart, spleen, brain, skin, triceps, tongue mucosa, intercostal skeletal muscle, subcutaneous fat, and abdominal fat) from twelve cadavers (age range of 29 week of gestation to 88 years old). The highest rTL variability was observed in peripheral leukocytes, and the lowest variability was found in brain. We found a significant linear correlation between leukocyte rTL and both intercostal muscle (R=0.68, P<0.02) and liver rTL (R=0.60, P<0.05) only. High rTL variability was observed between different organs from one individual. Furthermore, we have shown that even slight DNA degradation (modeled by sonication of genomic DNA) leads to false rTL shortening. We conclude that the rTL in peripheral leukocytes is not strongly correlated with the rTL in different organs.

Comparison of relative telomere length measured in aortic tissue and leukocytes in patients with end stage heart failure

OBJECTIVES

Telomeres are repetitive non-coding DNA sequences on the ends of eukaryotic chromosomes. Relative leukocyte telomere length (LrTL) is considered to reflect biological ageing and fitness. Therefore, we examined whether LrTL would reflect rTL in aortic tissue (ArTL) and whether it could be used as a marker of biological heart age.

DESIGN

We analysed telomere length in aortic and leukocyte samples from 73 heart recipients (63 males, 10 females; age 52.2±11.7 years). Relative telomere length was measured using a quantitative PCR-based method.

RESULTS

Neither LrTL nor ArTL correlated significantly with the age of heart recipients. Mean ArTL was slightly shorter than LrTL (p=0.06) and there was a slight but significant inverse correlation between LrTL and ArTL (p=0.019).

CONCLUSIONS

The age of patients with end stage heart failure was not associated with leukocyte or aortic telomere length. An inverse correlation between LrTL and ArTL suggests that LrTL is unlikely to be an important predictor of biological ageing in these patients.

FTO first intron rs1558902 variant and platelets count in white middle-aged women: prague pre- and post-menopausal females (3PMFs) study

The polymorphisms within the FTO gene play an important role in the genetic determination of body weight and body mass index and have been associated with cardiovascular disease, but the causal mechanism is still a matter of debate. The possible effect on the platelet count as a marker of hemocoagulation status as a possible cardiovascular risk factor was suggested in Japanese population. We have analyzed both rs1558902 FTO polymorphism (T > A) and platelet counts in the Prague Pre and Post Menopausal Females (3PMFs) study, including those of 669 women (mean age, 55.7 ± 2.7 years). The frequencies of the FTO genotypes were similar to other populations (TT, 30.4%; TA, 48.1%; and AA, 21.5%). We have not detected a significant association between the FTO rs1558902 variant and platelet counts in white women (TT, 242 ± 55 × 10; TA, 246 ± 67 × 10; and AA, 247 ± 55 × 10; F[2.642] = 0.30, P = 0.75). At least in white persons, platelet count seems not to be a link between the FTO variation and risk of cardiovascular disease.

Association between FTO 1st intron tagging variant and telomere length in middle aged females. 3PMFs study

The FTO gene plays an important role in the determination of body weight and BMI and it has been suspected of being associated with all-cause mortality, cardiovascular disease, cancer and end stage renal disease, but the causal mechanism of these effects is still unknown. One of the possibilities is the potential association with telomere length. Telomeres are repetitive DNA-sequences located at the ends of eukaryotic chromosomes' length of which is reduced in all somatic cells during ageing. Out of the 908 females (3PMFs study), in 783 females both FTO 1st intron tagging polymorphism (G>T, rs17817449) and the relative telomere length were successfully analysed. The relative telomere length was calculated as the ratio of telomere repeats to single-copy gene copies. The frequencies of the FTO genotypes were similar to other populations (GG=18.3%, GT=49.1% and TT=32.6%). We have detected, that the relative telomere length was significantly shorter (P<0.02, P<0.01 after adjustment for age, BMI, waist and subcutaneous fat), in carriers of at least one FTO risky (G) allele (0.85±0.39) in comparison to the carriers of the protective TT genotype (0.93±0.48). We have demonstrated that the FTO variant could be associated with the relative telomere length. Whether this represents a causality of association between the FTO variant and the non-communicable diseases needs to be further analysed.

Lack of an association between three tagging SNPs within the FTO gene and smoking behavior

INTRODUCTION

Using genome-wide screening, a polymorphism within the second intron of the FTO gene (rs2302673) was found to be associated with smoking habits in females. In a population-based, cross-sectional study, we analyzed three tagging FTO single-nucleotide polymorphisms (SNPs) for their association with smoking behavior.

METHODS

Subjects from the Czech post-MONICA study, including 1,191 adult males (32.1% smokers) and 1,368 adult females (22.5% smokers) were included in this study. Smoking habits were obtained through questionnaire data analysis, and three FTO tagging SNPs were genotyped (rs17817449: intron 1, rs2302673: intron 2, and rs17818902: intron 3).

RESULTS

We detected slightly lower frequencies (p = .043) of the GG genotype of the rs17818902 SNP in males who quit smoking compared with others. However, the significance disappeared after adjusting for multiple testing. Within the entire population, or in either males or females alone, we failed to detect a significant difference between other FTO genotypes and smoking status. Also, the number of cigarettes smoked per day was independent of individual FTO genotypes in both genders.

CONCLUSIONS

We did not find an association between the FTO gene tagging variants and smoking status. FTO is unlikely to be a major genetic determinant of smoking status.

The FTO gene polymorphism is associated with end-stage renal disease: two large independent case-control studies in a general population

BACKGROUND

Genome-wide association studies identified the FTO (fat mass and obesity gene) gene as an important determinant of body weight. More recently, the FTO gene was reported to be associated with other outcomes, including major risk factors for chronic kidney disease (CKD). We investigated the role of this gene in the risk of end-stage renal disease (ESRD) caused by CKD.

METHODS

We conducted two large population-based case-control studies of ESRD. Study 1 compared 984 haemodialysed patients with ESRD with 2501 participants in the Czech post-MONICA study; Study 2 compared 1188 patients included in a kidney transplantation programme for ESRD with 6681 participants in the Czech HAPIEE study. The frequencies of the FTO rs17817449 single nucleotide polymorphism genotype were compared between cases and controls.

RESULTS

The FTO rs17817449 genotype was significantly associated with CKD in both studies (P-values 0.00004 and 0.006, respectively). In the pooled data, the odds ratios of CKD for GG and GT, versus TT genotype, were 1.37 (95% confidence interval 1.20-1.56) and 1.17 (1.05-1.31), respectively (P for trend <0.0001). Among haemodialysed and kidney transplant patients, the onset of ESRD in GG homozygotes was 3.3 (P = 0.012) and 2.5 (P = 0.032) years, respectively, earlier than in TT homozygotes.

CONCLUSIONS

These two large independent case-control studies in the general population found robust associations between the FTO rs17817449 polymorphism and the ESRD. The results suggest that the morbidities associated with the FTO gene include CKD.