A characteristic feature of malignant cells, such as colorectal cancer cells, is a profound decrease in the level of 5-hydroxymethylcytosine, a product of 5-methylcytosine oxidation by TET enzymes. Recent studies showed that ascorbate may upregulate the activity of TET enzymes in cultured cells and enhance formation of their products in genomic DNA. The study included four groups of subjects: healthy controls (n = 79), patients with inflammatory bowel disease (IBD, n = 51), adenomatous polyps (n = 67) and colorectal cancer (n = 136). The list of analyzed parameters included (i) leukocyte levels of epigenetic DNA modifications and 8-oxo-7,8-dihydro-2′-deoxyguanosine, a marker of oxidatively modified DNA, determined by means of isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with tandem mass spectrometry, (ii) expression of TET mRNA measured with RT-qPCR, and (iii) chromatographically-determined plasma concentrations of retinol, alpha-tocopherol and ascorbate. Patients from all groups presented with significantly lower levels of 5-methylcytosine and 5-hydroxymethylcytosine in DNA than the controls. A similar tendency was also observed for 5-hydroxymethyluracil level. Patients with IBD showed the highest levels of 5-formylcytosine and 8-oxo-7,8-dihydro-2′-deoxyguanosine of all study subjects, and individuals with colorectal cancer presented with the lowest concentrations of ascorbate and retinol. A positive correlation was observed between plasma concentration of ascorbate and levels of two epigenetic modifications, 5-hydroxymethylcytosine and 5-hydroxymethyluracil in leukocyte DNA. Moreover, a significant difference was found in the levels of these modifications in patients whose plasma concentrations of ascorbate were below the lower and above the upper quartile for the control group. These findings suggest that deficiency of ascorbate in the blood may be a marker of its shortage in other tissues, which in turn may correspond to deterioration of DNA methylation-demethylation. These observations may provide a rationale for further research on blood biomarkers of colorectal cancer development.

Introduction: Inflammatory bowel disease (IBD) is a group of chronic gastrointestinal diseases with frequent systemic complications that are incurable according to current knowledge. These diseases adversely affect various areas of life, lowering patients' quality of life. One of the most frequently reported symptoms is fatigue. Aim: Translation and validation of the IBD-F patient self-assessment scale with a Polish IBD population. Material and methods: After consent from the author of the questionnaire had been obtained, the questionnaire was translated using the forward- and back-translation method. After arriving at the final Polish version of the questionnaire and ensuring that the questions and statements were comprehensible, the questionnaire was validated with a group of 129 IBD patients. Results: High values of intraclass correlation coefficient ( ICC) were achieved for overall results in both parts of the IBD-F questionnaire between test and retest (values exceeding 0.75). A high Cronbach's a consistency coefficient was achieved for the entire IBD-F questionnaire, both in the test and in the retest (0.968 and 0.975, respectively). Broken down into parts, Cronbach's a coefficient for Section I (presence and severity of fatigue) of the IBD-F questionnaire was 0.883, and for Section II (impact of fatigue on the person's life) it was 0.966. All patients evaluating the Polish version of the IBD-F questionnaire deemed the content of the questions comprehensible. Conclusions: The analysis of the results obtained, the Polish version of the IBD-F questionnaire was considered valid, reliable, and clinically useful.

Colonoscopy is the gold standard for diagnosing and monitoring gastrointestinal diseases. However, bowel preparation, rather than the procedure itself, appears to be the main driver of transient gut microbiota disruption. Available evidence suggests that microbiota alterations after bowel preparation and colonoscopy may persist for days to weeks and may be associated with changes in barrier function, microbial metabolism, and symptom burden in susceptible individuals. This review summarizes current knowledge on the mechanisms underlying microbial disruption induced by bowel preparation, including loss of diversity, shifts in key taxa, impairment of metabolic pathways, and alterations in immunomodulatory metabolites. It also discusses potential clinical consequences and highlights nutritional strategies that may support microbiota recovery, including dietary fiber, polyphenols, and microbiota-targeted approaches. This review also highlights current research gaps and the need for well-designed clinical studies in this field.