The aortic expression pattern of mechanosensitive stem cell genes is spatially deranged by western-type diet but can be regulated with colchicine-based anti-inflammatory treatment
Authors: Mylonas K , Sarantis P , Kapelouzou A , Karamouzis M , Iliopoulos D , Nikiteas N , Schizas D 
Published: October 2022

Abstract

Background
Inflammatory dysregulation of mechanosensitive stem cell genes may be central to atherogenesis.

Purpose
In the present animal model, we utilized colchicine-based regimens to curtail the development of thoracic and abdominal aortic atheromatosis. We also explored the effect of anti-inflammatory therapy on atheroprotective (Klotho, HOXA5, NOTCH1, OCT4) and proatherogenic (HIF1a, SOX2, BMP4, NANOG) genes.

Methods
Twenty-eight New Zealand White rabbits were divided to four groups. The control group (n=6) was fed standard chow, group A (n=6) was fed chow enriched with 1% w/w cholesterol, group B (n=8) was fed the same cholesterol-enriched diet plus 2 mg/kg body weight/day colchicine and 250 mg/kg body weight/day fenofibrate, while group C (n=8) was fed the same diet plus 2 mg/kg body weight/day colchicine and 15 mg/kg body weight/day N-acetylcysteine (NAC). After seven weeks, all animals were euthanized, and their aortas were resected. Atherosclerotic plaque area was estimated via morphometric analysis. Gene expression was quantified with qRT-PCR.

Results
Group A developed significantly more extensive thoracic and abdominal aortic atherosclerosis compared to groups B (p&lt;0.001) and C (p&lt;0.001). Combining colchicine with NAC instead of fibrate resulted in stronger atheroprotection both in the thoracic (MD: 6.6, 95% CI: 0.9–12.3) and the abdominal aorta (MD: 11.1, 95% CI: 6.0–16.3). In group A thoracic aortas, Klotho was downregulated compared to controls (MD: 8.79, 95% CI: 1.82–15.76). Both colchicine regimens upregulated Klotho back to baseline levels (p&lt;0.001). Colchicine/fenofibrate also significantly upregulated thoracic NOTCH1 compared to controls (MD: −4.29, 95% CI: −8.09 to −0.48). Colchicine/NAC significantly reduced thoracic NANOG expression compared to hyperlipidemic diet alone (MD: 4.33, 95% CI: 0.37–8.29). In the abdominal aorta, cholesterol-enriched diet alone resulted in significant downregulation of HOXA5 (MD: 1.39, 95% CI: 0.03–2.74) which was reversed with colchicine/NAC back to baseline levels (MD: 0.16, 95% CI: −1.19 to 1.51). On the other hand, colchicine/fenofibrate downregulated HIF1a compared to baseline (MD: 3.64, 0.83–6.44). No statistically significant differences were noted in terms of BMP4, SOX2, and OCT4 expression in thoracic and abdominal aortic specimens.

Conclusions
The aortic expression pattern of mechanosensitive stem cell genes is spatially influenced by western-type diet and can be modified using anti-inflammatory regimens. In our experiment, hyperlipidemic diet drove thoracic and abdominal aortic atheromatosis by downregulating Klotho and HOXA5, respectively. Both colchicine regimens curtailed thoracic atheromatosis via upregulating Klotho. In the thoracic aorta, combining colchicine with fenofibrate also increased NOTCH1, while the addition of NAC reduced NANOG. In the abdominal aorta, combining colchicine with fenofibrate reduced HIF1a, whereas the addition of NAC upregulated HOXA5.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): This research was funded by the Hellenic Surgical Society and the Hellenic Atherosclerosis Society.