Abstract (eng)
Atherosclerosis is a widespread disease throughout Western society and its consequences - heart attack and stroke belong to the most common causes of death. Present therapeutical strategies lower risk factors (e.g. introducing diet, exercise), treat co-morbidities (like hypertension or diabetes) or surgically widen narrowed vessels. [1–3]
VSMC, which are stimulated to proliferate by intravascular inflammatory processes, enforce the formation of atherosclerotic plaques in multiple ways. These include the production of ECM and liberation of cytokines, which promote inflamation and storage of LDL in the intima of blood vessels. Therefore, the inhibition of proliferating VSMC is a potential therapeutic approach, which helps to reduce the progression of atherosclerosis. [4–6] Moreover, since the re-narrowing of the vessel is mainly caused by VSMC proliferation, antiproliferative treatment can potentially reduce the risk of restenosis after angioplasty. [7]
Based on a study on the antiproliferative effect of RAME (rosmarinic acid methyl ester) on VSMC (vascular smooth muscle cells), for this thesis I tested rosmarinic acid, five of its esters (RAME, RAET, RABU, RAOCT, RADOD) and its metabolites for their effect on VSMC proliferation.
All tested esters showed an antiproliferative effect on VSMC in both Resazurin and Crystal Violet Assay and arrested the cells in the G0/G1 phase of the cell cycle according to the cell cycle analysis. In contrast, RA metabolites did not inhibit cell proliferation. Except for RADOD, the antiproliferative effect was concentration-dependent. Similar IC50 values of RAME, RAET, RABU and RAOCT showed that the effectiveness does not correlate to the length of the ester side chain. Detection of fragmented DNA in samples during the cell cycle analysis and the changed morphology of cells under the microscope indicated a potential toxic effect of RA esters with longer side chains. Results from the Western Blot showed that the tested RA derivatives inhibit phosphorylation of Rb in Ser807/811 the same way RAME did previously.
All in all, the results of this thesis indicate that RA esters with shorter side chain are interesting candidates for further examination, whereas for esters with longer side chains, toxicity has to be ruled out first.