Comparative Experimental Studies of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers against Two Different Models of Angiogenesis

Objective: Angiogenesis, the formation of new capillary blood vessels. We have compared the effect of two Angiotensin-Converting Enzyme inhibitors (ACEIs) and two Angiotensin Receptor Blockers (ARBs) for its anti-angiogenic property to pinpoint their role in capillary growth. Methods: The antiangiogenic activity of ACEIs (Lisinopril, Ramipril) and ARBs (Losartan, Valsartan) were evaluated by in-ovo using and in-vivo methods by using chick embryo Chorioallantoic membrane (CAM) assay and sponge implantation method respectively. All the test drugs were tested at three dose level and Suramin was considered as standard. Before coming to the final conclusion various parameters were studied like angiogenic score, the number of branching points and micro-vessels in CAM assay, whereas the determination of Hb content, wet weight of the implants and VEGF was carried out in sponge implantation model. Results: Among all the drugs Losartan, AT1R blocker has shown a promising anti-angiogenic effect against both the models. Valsartan has also shown modest anti-angiogenic activity but not as good as Losartan. Losartan has shown significant (p<0.005) dosedependent decrease in the number of blood vessels, new branching points, angiogenic score and the decrease in wet weight, Hb content and VEGF content in the implants compared to normal control group. There was no significant difference were observed in any of the parameters by ACEI. Conclusion: Losartan possesses a significant potential to inhibit angiogenesis and this property could be useful in controlling metastasis in malignant cancerous tumors.