Objective
Clinical relevance of global DNA methylation and one‐carbon metabolite levels with histological severity remains uncertain in patients with nonalcoholic fatty liver disease (NAFLD). This study aimed to evaluate hepatic global DNA methylation and serum one‐carbon metabolite concentrations in patients with NAFLD and the possible associations of these parameters with liver histology.
Methods
Liver biopsies from 18 control participants and 47 patients with NAFLD were evaluated.
Results
The hepatic global DNA methylation level was significantly lower in the NAFLD group than in the control group among participants with overweight. Participants with moderate inflammation and mild fibrosis had significantly lower levels of global DNA methylation than those without these characteristics. Participants with borderline nonalcoholic steatohepatitis had significantly lower global DNA methylation levels than controls. The hepatic global DNA methylation level tended to decrease with the increasing hepatic inflammation grade and disease progression. The NAFLD group had a significantly higher serum homocysteine concentration than the control group among participants with overweight. This level tended to increase with increasing hepatic steatosis grade and disease progression.
Conclusions
Patients with NAFLD exhibited lower hepatic levels of global DNA methylation and elevated serum homocysteine concentrations, which are associated with the histological severity of NAFLD.
β-Carotene has been reported to alleviate hepatic steatosis (SS), inflammation, and fibrosis in vivo and vitro studies. However, the clinical relevance of serum β-carotene and β-carotene-to-retinol (SC/SR) ratio with histological severity in nonalcoholic fatty liver disease (NAFLD) patients is unknown. This case-control study enrolled 24 control subjects and 62 NAFLD patients. Liver biopsies were collected and histological characteristics were assessed. Information with regard to demographic, anthropometric and dietary intake was assessed by face-to-face interviews with questionnaire. Serum β-carotene and retinol concentrations were determined by the HPLC method. Serum β-carotene and SC/SR levels in NAFLD patients were significantly lower than these in controls (0.23 ± 0.01 vs. 0.35 ± 0.04 μmol/L, 0.38 ± 0.03 vs. 0.84 ± 0.10). Compared with individuals without SS, both β-carotene and SC/SR levels were significantly decreased in those with moderate SS (0.34 ± 0.03 vs. 0.21 ± 0.02 μmol/L, 0.76 ± 0.09 vs. 0.37 ± 0.05). Subjects with mild inflammation had a significantly lower β-carotene and SC/SR levels than those without inflammation (0.23 ± 0.01 vs. 0.33 ± 0.04 μmol/L, 0.77 ± 0.09 vs. 0.38 ± 0.03). Serum SC/SR was significantly lower in patients with mild fibrosis than those without fibrosis (0.45 [0.27–0.83] vs. 0.34 [0.26–0.51]). According to the NAFLD Activity Scoring score, both β-carotene and SC/SR gradually decreased with disease progression from normal liver, simple SS to steatohepatitis borderline (ptrend ≤ 0.001). These results show that NAFLD patients have lower circulating β-carotene concentration and SC/SR ratio, which are associated with the histological severity of NAFLD.
Radiotherapy remains an effective conventional method of treatment for patients with cancer. However, the clinical efficacy of radiotherapy is compromised by the development of radioresistance of the tumor cells during the treatment. Consequently, there is need for a comprehensive understanding of the regulatory mechanisms of tumor cells in response to radiation to improve radiotherapy efficacy. The current study aims to highlight new developments that illustrate various forms of cancer cell death after exposure to radiation. A summary of the cellular pathways and important target proteins that are responsible for tumor radioresistance and metastasis is also provided. Further, the study outlines several mechanistic descriptions of the interaction between ionizing radiation and the host immune system. Therefore, the current review provides a reference for future research studies on the biological effects of new radiotherapy technologies, such as ultra-high-dose-rate (FLASH) radiotherapy, proton therapy, and heavy-ion therapy.
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