Dipartimento di Biologia, Unità di Genetica, Mutagenesi ed Epidemiologia Ambientale, University of Pisa, via Derna 1, 56100 Pisa, Italy.
FASEB J. 2011 Feb;25(2):685-93. doi: 10.1096/fj.10-168427. Epub 2010 Nov 10.
Childhood obesity, often characterized by a chronic low-grade inflammation, has been associated with an increased risk of developing some types of cancer later in life. Nuclear γ-H2AX foci represent the first detectable response of cells to DNA tumorigenesis lesions, such as the double-strand breaks (DSBs). An excess of micronucleated peripheral lymphocytes was found in subjects with cancer or inflammation-based diseases. We set out to investigate the expression of genome damage, from DNA lesions to chromosome mutations (micronuclei), in overweight and obese children. Using the γ-H2AX focus assay and micronucleus (MN) test, we analyzed peripheral lymphocytes from 119 Italian children classified as normal weight (n=38), overweight (n=20), or obese (n=61). Cultures treated with bleomycin (BLM) were also set up for each child in both assays to check functioning of the apparatus that ensures DNA integrity. We measured serum TNF-α, IL-6, and C-reactive protein (CRP) as markers of inflammation. Overweight and obese children had significantly higher levels of H2AX phosphorylation (0.0191±0.0039 and 0.0274±0.0029 γ-H2AXF/n) and increased MN frequencies (2.30±0.25 and 2.45±0.22‰) than normal-weight children (0.0034±0.0006 γ-H2AXF/n, and 0.92±0.12‰ MN), while all subjects responded to BLM induction, irrespective of their weight status. The fold increase of spontaneous MN frequencies in overweight and obese subjects was 2.5 and 2.7, respectively, well below the corresponding increase in the γ-H2AX foci (5.6- and 8.0-fold, respectively). IL-6 and CRP mean values were significantly higher in obese and overweight children than in controls. Here, we demonstrated that peripheral cells of overweight and obese children showed increased levels of DSBs, which were not completely repaired as part of them has been converted into micronuclei. Characterization of childhood obesity inflammation could be implemented using molecular markers of genome damage.
儿童肥胖症常伴有慢性低度炎症，与成年后患某些类型癌症的风险增加有关。核 γ-H2AX 焦点代表细胞对肿瘤发生的 DNA 损伤（如双链断裂）的最早可检测反应。在患有癌症或炎症性疾病的患者中发现外周血淋巴细胞微核过多。我们着手研究超重和肥胖儿童的基因组损伤表达，从 DNA 损伤到染色体突变（微核）。使用 γ-H2AX 焦点测定法和微核（MN）试验，我们分析了来自 119 名意大利儿童的外周血淋巴细胞，这些儿童分为正常体重（n=38）、超重（n=20）或肥胖（n=61）。还为每个孩子在两种试验中都建立了用博来霉素（BLM）处理的培养物，以检查确保 DNA 完整性的仪器的功能。我们测量了血清 TNF-α、IL-6 和 C 反应蛋白（CRP）作为炎症标志物。与正常体重儿童相比，超重和肥胖儿童的 H2AX 磷酸化水平（0.0191±0.0039 和 0.0274±0.0029 γ-H2AXF/n）显著升高，微核频率（2.30±0.25 和 2.45±0.22‰）也显著升高（0.0034±0.0006 γ-H2AXF/n，和 0.92±0.12‰ MN），而所有受试者均对 BLM 诱导有反应，无论其体重状况如何。超重和肥胖受试者自发 MN 频率的倍数增加分别为 2.5 和 2.7，均远低于 γ-H2AX 焦点的相应增加（分别为 5.6-和 8.0 倍）。肥胖和超重儿童的 IL-6 和 CRP 平均值明显高于对照组。在这里，我们证明超重和肥胖儿童的外周细胞显示出较高水平的双链断裂，其中部分双链断裂未完全修复，已转化为微核。使用基因组损伤的分子标志物可以对儿童肥胖症炎症进行特征描述。
