DNA methylation (leading to gene silencing) is one of the best-studied epigenetic mechanisms. It is also essential in regulating the dynamics of dopamine release in the synaptic cleft. This regulation relates to the expression of the dopamine transporter gene (DAT1). We examined 137 people addicted to nicotine, 274 addicted subjects, 105 sports subjects and 290 people from the control group. After applying the Bonferroni correction, our results show that as many as 24 out of 33 examined CpG islands had statistically significantly higher methylation in the nicotine-dependent subjects and athletes groups compared to the control group. Analysis of total DAT1 methylation revealed a statistically significant increase in the number of total methylated CpG islands in addicted subjects (40.94%), nicotine-dependent subjects (62.84%) and sports subjects (65.71%) compared to controls (42.36%). The analysis of the methylation status of individual CpG sites revealed a new direction of research on the biological aspects of regulating dopamine release in people addicted to nicotine, people practicing sports and people addicted to psychoactive substances.

Adiponectin is a secretory protein of adipocytes that plays an important role in pathological processes by participation in modulating the immune and inflammatory responses. The pro-inflammatory effect of adiponectin is observed in rheumatoid arthritis (RA). In this study, we examined adiponectin plasma levels and the expression of adiponectin in bone marrow tissue samples, synovium samples, and infrapatellar fat pad samples from patients with osteoarthritis (OA) and RA. Additionally we examined the expression of adiponectin receptors AdipoR1 and AdipoR2 in synovium samples and infrapatellar fat pad samples from patients with OA and RA. We also assessed the correlations between adiponectin plasma concentrations, adiponectin expression in bone marrow, synovium, infrapatellar fat pad, and plasma levels of selected cytokines. We found increased expression of adiponectin in synovium samples and infrapatellar fat pad samples from patients with RA as compared to patients with OA. There were no statistically significant differences of adiponectin plasma levels and adiponectin expression in bone marrow tissue samples between OA and RA patients. There were no differences in the expression of AdipoR1 and AdipoR2 at the mRNA level in synovial tissue and the infrapatellar fat pad between RA and OA patients. However, in immunohistochemical analysis in samples of the synovial membrane from RA patients, we observed very strong expression of adiponectin in intima cells, macrophages, and subintimal fibroblasts, such as synoviocytes, vs. strong expression in OA samples. Very strong expression of adiponectin was also noted in adipocytes of Hoffa’s fat pad of RA patients. Expression of AdipoR1 was stronger in RA tissue samples, while AdipoR2 expression was very similar in both RA and OA samples. Our results showed increased adiponectin expression in the synovial membrane and Hoffa’s pad in RA patients compared to that of OA patients. However, there were no differences in plasma adiponectin concentrations and its expression in bone marrow. The results suggest that adiponectin is a component of the inflammatory cascade that is present in RA. Pro-inflammatory factors enhance the expression of adiponectin, especially in joint tissues—the synovial membrane and Hoffa’s fat pad. In turn, adiponectin also increases the expression of further pro-inflammatory mediators.

The use of ‘new psychoactive substances’ appears to be increasingly common. The aim of this study was to examine biological and personality determinants in individuals who choose to use these substances, which may help in the prevention and treatment of psychoactive substance use disorders. The study group consisted of 374 male volunteers; all were users of ‘new psychoactive substances’ (NPS). The NPS users were recruited after they had abstained—for at least 3 months—from any substance of abuse in addiction treatment facilities. The NPS patients and the control subjects were examined by a psychiatrist using the Mini-International Neuropsychiatric Interview (M.I.N.I.), the NEO Five-Factor Personality Inventory (NEO-FFI), and the State-Trait Anxiety Inventory (STAI) scales. The real-time PCR method was used for genotyping. When we compared the controls with the study group, statistically significant interactions were found between DAT1 polymorphism, neuroticism, and NPS use. NPS use and DAT1 polymorphism were associated with a higher level of neuroticism on the NEO-FFI scale. The study group of NPS users showed a higher severity of anxiety symptoms, both in terms of trait and state, compared to the control group. The results may support the idea that neuroticism and anxiety correlate strongly with coping motives for using NPS.

Background: Vitamin D receptor (VDR) polymorphisms may influence immune regulation and musculoskeletal health, but their perioperative role is not well understood. This study investigated the rs2228570 (FokI) variant in relation to inflammatory, hematologic, and patient-reported outcomes in orthopedic patients. Methods: We genotyped 300 orthopedic patients and 200 healthy controls using real-time PCR. Regression models in patients adjusted for age and body mass index (BMI) examined associations between rs2228570 genotypes and laboratory as well as clinical outcomes. Results: The CC genotype (homozygous cytosine) was associated with higher white blood cell count (β = 0.52, p = 0.0435), higher lymphocyte count (β = 0.26, p = 0.00025), higher hemoglobin (β = 0.57, p = 0.00197), and higher hematocrit (β = 1.42, p = 0.01102). The TT genotype (homozygous thymine) was associated with higher C-reactive protein (β = 10.90, p = 0.00329), lower mean corpuscular volume (β = −1.63, p = 0.04909), and higher health-related quality of life assessed by the 36-Item Short-Form Health Survey (SF-36) (β = 6.31, p = 0.00009). Conclusions: The rs2228570 polymorphism in the VDR gene is associated with distinct perioperative inflammatory, hematologic, and patient-reported profiles. These findings support the potential clinical utility of VDR genotyping, in combination with routine laboratory tests, to refine perioperative risk stratification and guide personalized rehabilitation in orthopedic patients.

Background: Dopaminergic signaling is a key mechanism in behavioral regulation and impulse control. While DAT1 promoter methylation has been linked to behavioral dysregulation in clinical groups, its role in high-functioning populations such as elite athletes remains unclear. Objectives: To compare DAT1 promoter methylation, DAT1 VNTR genotype, and impulsivity between elite combat sport athletes and matched controls, and to assess potential gene–environment interactions. Methods: The study included 209 male participants (100 elite combat athletes, 109 controls). Methylation of 33 CpG sites within the DAT1 promoter was quantified from peripheral blood DNA. DAT1 VNTR genotypes were determined via PCR and gel electrophoresis. Impulsivity was assessed using the Barratt Impulsiveness Scale (BIS-11). Group differences and interactions were analyzed using analysis of variance (ANOVA), non-parametric tests, and post hoc comparisons. Results: Athletes displayed significantly higher overall DAT1 promoter methylation and lower impulsivity scores across all BIS-11 subscales compared with controls. A significant group × genotype interaction for methylation indicated genotype-specific epigenetic differences by athletic status. No differences in VNTR genotype or allele frequencies were observed. Conclusions: Elevated DAT1 promoter methylation in elite athletes may be associated with enhanced behavioral control, potentially reflecting neurobiological adaptations to high-intensity training. These results highlight the need to integrate genetic and epigenetic perspectives in sports science. Longitudinal and multi-omics studies are warranted to determine causal links and evaluate the potential of epigenetic markers as indicators of performance-related traits.

Background: Genetic variability in the vitamin D receptor (VDR) may influence immune regulation and systemic inflammation, factors potentially relevant for outcomes in orthopedic surgery. This study explored the association of the VDR rs7975232 (ApaI) single nucleotide variation (SNV) with inflammatory biomarkers and health-related quality of life (HRQoL). Methods: The study included 292 orthopedic patients and 90 controls. Genotyping was performed using real-time PCR. Laboratory analyses comprised hematological parameters, C-reactive protein (CRP), and serum 25-hydroxyvitamin D₃ [25(OH)D₃]. HRQoL was assessed with the SF-36 questionnaire. Associations between genotype, inflammation, and HRQoL were examined using regression models adjusted for age and body mass index (BMI). Results: Genotype (p = 0.023) and allele (p = 0.007) distributions differed between patients and controls. In multivariable models, the CC genotype was associated with higher neutrophil counts (p = 0.029), whereas the AA genotype was associated with elevated CRP levels (p = 0.025). Genotypic variation was further associated with SF-36 scores, independently of age and BMI. Conclusions: The VDR rs7975232 SNV may be associated with baseline systemic inflammation and patient-reported quality of life in orthopedic surgery. Genotyping of this variant may complement conventional biomarkers in future research aimed at improving diagnostic precision. Moreover, it could contribute to innovation in laboratory diagnostics aimed at improving perioperative outcomes.