Post-surgical effects of angioplasty or bypass surgery include, an increase in the proliferation of the cells lining the blood vessels or vascular smooth muscle cells (VSMC). This results in narrowing of the blood vessel lumen and this condition is called restenosis (recurrence of narrowing of blood vessels).
Coronary angioplasty is a procedure which is performed to open the stenotic or blocked blood vessels (arteries), caused due to the deposition of cholesterol. But restenosis in these cases makes the procedure meaningless. To avoid restenosis , drug-eluting stents are placed inside the arteries during the procedure. A stent is a small metal mesh tube that acts as a scaffold to provide support inside the coronary artery. These drug eluting stents release drugs like paclitaxel and rapamycin that have anti-proliferative properties for VSMC. However these drugs do have side effects like impaired re-endothelialization and subsequent thrombosis induction.
To address this issue, a research team led by Dr. Atanas G. Atanasov from University of Vienna, Shanghai Research Center for TCM Modernization and Shanghai Institutes for Biological Sciences started to look at the plant-derived natural products as a cure for restenosis with least side effects unlike drugs. They have identified that capsaicin a bioactive component of chilli peppers have the ability to suppress VSMC proliferation.
From the experiments, it is understood that the number of cells were much lower in capsaicin treated samples and indeed capsaicin suppressed VSMC proliferation concentration-dependently with an IC50 of 5.36 μM when treated for 48 hours. Scientist confirmed the anti-proliferative property of capsaicin by measuring the total DNA content of the treated VSMC as the amount of DNA in cells is a direct indication of the total number of cells and rate of proliferation.
Also lactate dehydrogenase (LDH) assays were performed to evaluate the extent of cell death/damage. Researchers confirmed that less number of cells in capsaicin treatment is due to the inhibition of cell proliferation and not cell death. On the whole capsaicin could inhibit vascular smooth muscle cell (VSMC) proliferation and could be used as a drug for anti-restenosis. However this needs to be further tested in vivo models for restenosis and established before using Capsaicin as a drug for the treatment of restenosis.
The original publication can be accessed here.