Changes in gene methylation patterns in neonatal murine hearts: Implications for the regenerative potential.

BACKGROUND: The neonatal murine heart is able to regenerate after severe injury; this capacity however, quickly diminishes and it is lost within the first week of life. DNA methylation is an epigenetic mechanism which plays a crucial role in development and gene expression regulation. Under investigation here are the changes in DNA methylation and gene expression patterns which accompany the loss of regenerative potential. RESULTS: The MeDIP-chip (methylated DNA immunoprecipitation microarray) approach was used in order to compare global DNA methylation profiles in whole murine hearts at day 1, 7, 14 and 56 complemented with microarray transcriptome profiling. We found that the methylome transition from day 1 to day 7 is characterized by the excess of genomic regions which gain over those that lose DNA methylation. A number of these changes were retained until adulthood. The promoter genomic regions exhibiting increased DNA methylation at day 7 as compared to day 1 are significantly enriched in the genes critical for heart maturation and muscle development. Also, the promoter genomic regions showing an increase in DNA methylation at day 7 relative to day 1 are significantly enriched with a number of transcription factors binding motifs including those of Mfsd6l, Mef2c, Meis3, Tead4, and Runx1. CONCLUSIONS: The results indicate that the extensive alterations in DNA methylation patterns along the development of neonatal murine hearts are likely to contribute to the decline of regenerative capabilities observed shortly after birth. This conclusion is supported by the evidence that an increase in DNA methylation in the neonatal murine heart from day 1 to day 7 occurs in the promoter regions of genes playing important roles in cardiovascular system development.

Sex contribution to average age at onset of Huntington's disease depends on the number of (CAG)n repeats.

Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by the extension of the CAG repeats in exon 1 of the HTT gene and is transmitted in a dominant manner. The present study aimed to assess whether patients' sex, in the context of mutated and normal allele length, contributes to age on onset (AO) of HD. The study population comprised a large cohort of 3723 HD patients from the European Huntington's Disease Network's REGISTRY database collected at 160 sites across 17 European countries and in one location outside Europe. The data were analyzed using regression models and factorial analysis of variance (ANOVA) considering both mutated allele length and sex as predictors of patients' AO. AO, as described by the rater's estimate, was found to be later in affected women than in men across the whole population. This difference was most pronounced in a subgroup of 1273 patients with relatively short variants of the mutated allele (40-45 CAG repeats) and normal alleles in a higher half of length distribution-namely, more than 17 CAG repeats; however, it was also observed in each group. Our results presented in this observational study point to sex-related differences in AO, most pronounced in the presence of the short mutated and long normal allele, which may add to understanding the dynamics of AO in Huntington's Disease.Trial registration: ClinicalTrials.gov identifier NCT01590589.

Between therapy effect and false-positive result in animal experimentation.

Despite the animal models' complexity, researchers tend to reduce the number of animals in experiments for expenses and ethical concerns. This tendency makes the risk of false-positive results, as statistical significance, the primary criterion to validate findings, often fails if testing small samples. This study aims to highlight such risks using an example from experimental regenerative therapy and propose a machine-learning solution to validate treatment effects. The example analysed was the pharmacological treatment of ear pinna punch wound healing in mice. Wound closure data analysed included eight groups treated with an epigenetic inhibitor, zebularine, and eight control groups receiving vehicle alone, of six mice each. We confirmed the zebularine healing effect for all 64 pairwise comparisons between treatment and control groups but also determined minor yet statistically significant differences between control groups in five of 28 possible comparisons. The occurrences of significant differences between the control groups, regardless of standardised experimental conditions, indicate a risk of statistically significant effects in the case a compound lacking the desired biological activity is tested. Since the criterion of statistical significance itself can be confusing, we demonstrate a machine-learning algorithm trained on datasets representing treatment and control experiments as a helpful tool for validating treatment outcomes. We tested two machine-learning approaches, Naïve Bayes and Support Vector Machine classifiers. In contrast to the Mann-Whitney U-test, indicating enhanced healing effects for some control groups receiving saline alone, both machine-learning algorithms faultlessly assigned all animal groups receiving saline to the controls.

Total impact of oxidative stress genes on cardiovascular events-a 7-year follow-up study.

Cardiovascular (CV) events are the number one cause of lifetime disability and deaths worldwide. It is well known that traditional risk factors do not fully correlate with clinical outcomes; therefore, searching for other markers that would explain CV events' occurrence seems essential. Of importance, one of the main factors at the origin of CV events is oxidative stress, causing inflammation and atherosclerotic plaque instability. Therefore, the present study was conducted to evaluate eight carefully selected genetic polymorphisms related to oxidative stress as risk modifiers for CV events. A cohort of 1020 patients with coronary atherosclerosis was analysed in a 7-year follow-up observational study. The following end points were assessed: CV death, myocardial infarction (MI) and a combined end point of CV death/MI/stroke. Our results show that single polymorphisms are not significant cardiovascular disease risk factors, but genetic risk score (GRS), defined as the accumulation of our eight studied polymorphisms, was significantly associated with the three. Specifically, low GRS was associated with a higher risk of CV death, MI and CV death/MI/stroke. In conclusion, when regarding CV events, GRS investigated here can become clinically meaningful and undoubtedly adds to the knowledge in stratifying the risk of CV events.

Simple SIR models with Markovian control.

We consider a random dynamical system, where the deterministic dynamics are driven by a finite-state space Markov chain. We provide a comprehensive introduction to the required mathematical apparatus and then turn to a special focus on the susceptible-infected-recovered epidemiological model with random steering. Through simulations we visualize the behaviour of the system and the effect of the high-frequency limit of the driving Markov chain. We formulate some questions and conjectures of a purely theoretical nature.

Measured and predicted freeze-thaw days frequencies in climate change conditions in central Poland.

The rate of progression of geomorphological phenomena is greatly influenced by freeze-thaw processes. In the face of air temperature increasing over the past few decades, a question of the future impact of these processes arises, notably in the temperate and cold climate zones. Using the mean, maximum and minimum daily air temperature data in the period 1951-2018 obtained from three weather stations located in the vicinity of Jeziorsko reservoir (central Poland), we have determined the mathematical correlation, described with a polynomial function, between the mean monthly air temperature and the monthly number of freeze-thaw days (FTD). A freeze-thaw day is a day when the maximum air temperature is above 0 °C while the minimum air temperature equals or is below this threshold. The number of FTDs within the study area averaged 64-71 and demonstrated a downward trend of 2-4 FTDs/10 years. The study period (1951-2018), includes a clearly marked distinct sub-period (1991-2018), when the reservoir was in operation, which experienced 58-68 FTDs. Considering the assumed rise in temperature, one should expect a further, though slightly slower, decline in the future number of FTDs. Depending on the accepted model of the temperature increase, which for the area of Poland (Central Europe) in the perspective of 30 years oscillates between +1.1 to +1.3 °C, the number of FTDs within the study area is expected to decline by -4.5 to -5.3 FTD, i.e. 6-7% and 5.4-5.5 FTD i.e. 8-9% respectively.

Polish Adaptation of the Pregnancy-Related Anxiety Questionnaire-Revised 2 for All Pregnant Women.

Pregnancy-related anxiety (PrA) is a specific type of anxiety characteristic of the perinatal period. PrA can affect pregnancy and birth. However, no validated tool exists to measure PrA in Polish obstetric practice. The aim of this study was to translate the Pregnancy-Related Anxiety Questionnaire-Revised 2 (PRAQ-R2) into Polish and to evaluate its reliability and factorial and construct validity. This study was conducted in Poland as an online questionnaire in April 2020 and included 175 healthy women. To validate the PRAQ-R2, we used standardized tools for the measurement of general anxiety: the modified Visual Analog Scale (VAS), the Ten-Item Personality Inventory (TIPI), and the Hospital Anxiety and Depression Scale (HADS). Scale reliability was assessed using Cronbach's alpha. Concurrent validity was evaluated by calculating Spearman's rho correlation coefficients. Statistical analyses were performed using R ver. 4.0.2. Values for comparative fit index >0.90, Tucker-Lewis index >0.90, and root mean square error of approximation <0.08 indicated acceptable model fit, confirming the reliability of the three-factor structure of the translation. The subscales and total scores had good consistency (α > 0.7), and convergent validity was demonstrated. The PRAQ-R2 as translated into Polish represents the first validated tool in Poland to measure PrA for all pregnant women.

Association of Genes Related to Oxidative Stress with the Extent of Coronary Atherosclerosis.

Oxidative stress is believed to play a critical role in atherosclerosis initiation and progression. In line with this, in a group of 1099 subjects, we determined eight single nucleotide polymorphisms (SNPs) related to oxidative stress (PON1 c.575A>G, MPO c.-463G>A, SOD2 c.47T>C, GCLM c.-590C>T, NOS3 c.894G>T, NOS3 c.-786T>C, CYBA c.214C>T, and CYBA c.-932A>G) and assessed the extent of atherosclerosis in coronary arteries based on Gensini score. An increased risk of having a Gensini score in the higher half of the distribution was observed for the PON1 c.575G allele (odds ratio (OR) = 1.27, 95% confidence interval (CI): 1.004-1.617, p = 0.046). Next, the genetic risk score (GRS) for the additive effect of the total number of pro-oxidative alleles was assessed. We noted an increase in the risk of having a Gensini score above the median with the maximum number of risk alleles (OR = 2.47, 95% CI: 1.19-5.23, p = 0.014). A univariate Spearman's test revealed significant correlation between the total number of pro-oxidant alleles (GRS) and the Gensini score (ρ = 0.068, p = 0.03). In conclusion, the PON1 c.575A>G variant and the high number of risk alleles (GRS) were independent risk factors for a high Gensini score. We suggest, however, that GRS might occur as a more valuable component in adding a predictive value to the genetic background of atherosclerosis.

Folate/homocysteine metabolism and lung cancer risk among smokers.

BACKGROUND: Folate and homocysteine are involved in DNA synthesis and methylation processes, which are deregulated during carcinogenesis. OBJECTIVES: The aim of this study was to assess the relationship between folate/homocysteine concentrations, the functional polymorphisms of folate/homocysteine genes and lung cancer risk among cigarette smokers. STUDY DESIGN: The study included 132 lung cancer patients and 396 controls from northern Poland, matched by sex, age and smoking status. The median cigarette pack-years of smoking among both cases and controls was 30.0. Serum, red blood cell (RBC) folates and serum homocysteine concentrations were measured. The genotypes in selected polymorphic sites of the MTHFR, CBS, SHMT1, MTHFD1, MTRR, MTR, TYMS DHFR, TCN2, and SLC19A1 genes were determined. All study participants underwent scanning with low-dose computed tomography. RESULTS: Serum folate concentrations above the median (> 17.5 nmol/l among the healthy controls) were associated with an increased lung cancer risk (odds ratio [OR], 1.54, 95% confidence intervals [CI], 1.04-2.29, P = 0.031). An analogous trend was observed when the population was analysed after subdivision according to RBC folate concentrations, that is, above a value of 506.5 nmol/l (OR, 1.53; 95% CI, 0.95-2.47; P = 0.084). Additionally, in a subset of women, an increased risk of lung cancer development was associated with the SLC19A1 c.80AA genotype (c.80AA versus GG OR, 3.14; 95% CI, 1.32-7.46; P = P = 0.010). CONCLUSION: These results suggest that, in the population consisting of heavy smokers, high folate levels add to the cancerogenic effect of smoking.