Recombinant interleukin-2 (rIL-2) administration in oncology indications is hampered by vascular toxicity, which presents as a vascular leak syndrome. We used this aspect of the toxicity of rIL-2 to evaluate candidate biomarkers of drug-induced vascular injury (DIVI) in rats given 0.36 mg/kg rIL-2 daily. Groups of rats were given either 2 or 5 doses of rIL-2 or 5 doses of rIL-2 followed by a 7-day recovery. The histomorphologic lexicon and grading scheme developed by the Vascular Injury Working Group of the Predictive Safety Testing Consortium of the Critical Path Institute were utilized to enable semiquantitative integration with circulating biomarker levels. The administration of rIL-2 was associated with time-dependent endothelial cell hyperplasia and hypertrophy and perivascular inflammation that correlated with increases in circulating angiopoietin-2, lipocalin-2, monocyte chemotactic protein-1, tissue inhibitor of metalloproteinase-1, vascular endothelial growth factor A, E-selectin, and chemokine (C-X-C motif) ligand-1, and the microRNAs miR-21, miR-132, and miR-155. The dose groups were differentially identified by panels comprising novel candidate biomarkers and traditional hematologic parameters. These results identify biomarkers of the early stages of DIVI prior to the onset of vascular smooth muscle necrosis.
Objectives
Elevated free fatty acids in obesity and high-fat diets can negatively impact artery function, increasing the risk of cardiovascular diseases. Raspberries (RB) are a concentrated source of polyphenols which can mediate cellular pathways in a protective manner. Thus, the objective of this study was to examine whether RB consumption could mitigate the detrimental effects of a high-fat high-sucrose (HFHS) diet in the aorta of mice in vivo and human aortic endothelial cells (HAECs) in vitro.
Methods
Eight-week-old male C57BL/6 mice were fed an AIN-93M control diet with or without 10% w/w freeze-dried RB supplementation for 4 weeks. At week 4, animals were randomized into three groups: control, HFHS, or RB + HFHS. After 24 weeks of dietary treatment, mice were sacrificed and aortas dissected for immunohistochemistry analysis. HAECs were cultured in endothelial cell growth medium and treated with 200 μg/ml of RB extract in starvation medium. After 2 h, cells were treated with 100 μM of palmitic acid (PA) for 6 h. Cells were then collected for protein expression analysis via western blot. Data were normalized to control. Statistical analysis was conducted with ANOVA followed by Dunnett's multiple comparisons test.
Results
In aorta, nitrotyrosine was increased in the HFHS group compared with control and RB + HFHS group. Additionally, inducible nitric oxide synthase was increased in both HFHS and RB + HFHS compared to control, but expression was not different between HFHS groups. In HAECs, PA alone had no effect on phosphorylation of endothelial nitric oxide synthase (p-eNOSSer1177) compared to control. However, p-eNOSSer1177 expression was significantly increased in RB + PA -treated cells compared to both control and PA alone. Nuclear factor erythroid 2–related factor 2 (NRF2) and heme oxygenase (HO)-1 expression was also significantly increased with RB + PA treatment compared to control and PA alone.
Conclusions
Raspberry consumption may reduce vascular oxidative stress induced by a HFHS diet via reduced NO oxidation despite increased iNOS in vivo. Further in vivo investigation is needed to confirm whether these effects are mediated by increased NRF2 activity.
Funding Sources
Lewis College Foundation and Agriculture and Food Research Initiative (grant no. 2019–67,017-29,257/project accession no. 1,018,642) from the USDA National Institute of Food and Agriculture.
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