Skip to main content
Log in

Is the angiotensin ii type 2 receptor cerebroprotective?

  • Published:
Current Hypertension Reports Aims and scope Submit manuscript

Abstract

Most of the deleterious effects of angiotensin II (Ang II) on blood pressure (BP), cardiovascular remodeling, and atherosclerosis are mediated by Ang II type 1 (AT1)-receptor activation. This explains why Ang-II-decreasing or blocking drugs have been successful in decreasing global cardiovascular morbimortality in patients with cardiac complications. However, in primary or secondary stroke prevention trials in patients with low cardiac risk, β-blockers and angiotensin-converting enzyme inhibitors (ACEIs), which decrease Ang II formation, seem to be less protective than thiazides and dihydropyridines, which increase Ang II. When compared with a b-blocker, an Ang II-increasing AT1-receptor blocker better protects against stroke but not against cardiac events, whereas an ACEI gives the same protection against both cardiac and cerebral events. This dissociation between blood-pressure-independent cardiac and cerebral protection between β-blockers or ACEIs versus AT1-blockers in patients with low cardiac risk can be best explained if, besides the beneficial vascular effect of AT1-receptor blunting, there is evidence of a beneficial effect of non-AT1-receptor activation. In this review, we present experimental evidence for AT2- and AT4-receptor-mediated brain-anti-ischemic mechanisms and propose a direct comparison of AT1-blockers with ACEIs to prove the clinical effectiveness of non-AT1-mediated mechanisms in stroke prevention, particularly in patients with a higher risk for stroke than for cardiac complications.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References and Recommended Reading

  1. Dzau V: Theodore Cooper lecture: Tissue angiotensin and pathobiology of vascular disease: a unifying hypothesis. Hypertension 2001, 37:1047–1052. In this article, the current understanding of the tissular renin angiotensin system and its pathobiology in vascular disease are reviewed.

    PubMed  CAS  Google Scholar 

  2. Yusuf S, Peto R, Lewis J, et al.: Betablockade during and after myocardial infarction: an overview of randomized trials. Prog Cardiovasc Dis 1985, 27:335–371.

    Article  PubMed  CAS  Google Scholar 

  3. Flather MD, Yusuf S, Kober L, et al.: Long-term ACE-inhibitor therapy in patients with heart failure or left-ventricular dysfunction: a systematic overview of data from individual patients. ACE-Inhibitor Myocardial Infarction Collaborative Group. Lancet 2000, 355:1575–1581.

    Article  PubMed  CAS  Google Scholar 

  4. Jong P, Yusuf S, Rousseau M, et al.: Effect of enalapril on 12 years survival and life expectancy in patients with left ventricular dysfunction: a follow-up study. Lancet 2003, 361:1843–1848.

    Article  PubMed  CAS  Google Scholar 

  5. Pfeffer M, Swedberg K, Granger C, et al.: Effect of candesartan on mortality and morbidity in patients with chronic heart failure: the CHARM-overall programme. CHARM Investigators and Committees. Lancet 2003, 362:759–766.

    Article  PubMed  CAS  Google Scholar 

  6. Heart Outcomes Prevention Evaluation (HOPE) Study Investigators: Effects of angiotensin-converting-enzyme inhibitor on death from cardiovascular causes, myocardial infarction and stroke in high-risk patients. N Engl J Med 2000, 342:145–153.

    Article  Google Scholar 

  7. Fox K, Bertrand M, Remme W: Efficacy of perindopril in reduction of cardiovascular events among patients with stable coronary artery disease: randomised double blind placebo multicenter trial. For the investigators of EUROPA. Lancet 2003, 362:782–788.

    Article  PubMed  CAS  Google Scholar 

  8. Pfeffer M, Mc Murray J, Velasquez E, et al.: Valsartan, captopril or both in myocardial infarction complicated by heart failure, left ventricular dysfunction or both. The Valsartan in Acute Myocardial Infarction Trial (VALIANT) Investigator. N Engl J Med 2003, 349.

  9. Fournier A, Messerli FH, Achard JM, Fernandez L: Cerebroprotection mediated by angiotensin 2 (AT2) receptors: a hypothesis supported by recent randomized clinical trials. JACC 2004, 45:1143–1147. This review of large primary and secondary stroke prevention trials supported the hypothesis that diuretics, calcium channel blockers, and AT1-receptor blockers, which increase angiotensin II, were more cerebroprotective than b-blocker, or ACE-inhibitors, which decrease angiotensin II.

    Google Scholar 

  10. MRC Working Party: MRC trial of treatment of mild hypertension: principal results. Br Med J 1985, 291:97–104.

    Google Scholar 

  11. PATS Collaborating Group: Post-stroke Antihypertensive Study. Chinese Med J 1995, 108:710–717.

    Google Scholar 

  12. PROGRESS Collaborative Group: Randomized trial of a perindopril-based blood-pressure-lowering regimen among 6105 individuals with previous stroke or transient ischaemic attack. Lancet 2001, 358:1033–1041. This trial has established the combination of perindopril + indapamide as the gold standard antihypertensive treatment for preventing stroke recurrence (relative risk = 0.57); however, a comparison of perindopril alone with indapamide alone evidenced that angiotensin II-increasing diuretics are more stroke protective than angiotensin II-decreasing ACEI.

    Article  Google Scholar 

  13. Dahlöf B, Devereux R, Kjeldsen S, et al.: Cardiovascular morbidity and mortality in the losartan intervention for endpoint reduction in hypertension study (LIFE): a randomised trial against atenolol. Lancet 2002, 359:995–1003. This trial comparing losartan with atenolol in elderly hypertensive patients with LVH showed that sartans did not provide greater cardiac protection over b-blockers, in spite of the greater LVH regression evidencing greater AT1-receptor blunting, and mainly cerebral protection.

    Article  PubMed  Google Scholar 

  14. Saavedra J: Emerging features of brain angiotensin receptors. Regul Pept 1999, 85:31–45.

    Article  PubMed  CAS  Google Scholar 

  15. Vraamark T, Waldemar G, Strandgaard S, Paulson O: Angiotensin II receptor antagonist CV-11974 and cerebral blood flow autoregulation. J Hypertens 1995, 13:755–761.

    Article  PubMed  CAS  Google Scholar 

  16. Sadoshima S, Kenichiro F, Ooboshi H, et al.: Angiotensin converting enzyme inhibitors attenuate ischemic brain metabolism in hypertensive rats. Stroke 1993, 24:1561–1567.

    PubMed  CAS  Google Scholar 

  17. Werner C, Hoffman WE, Kochs E, et al.: Captopril improves neurologic outcome from incomplete cerebral ischemia in rats. Stroke 1991, 22:910–914.

    PubMed  CAS  Google Scholar 

  18. Inada Y, Wada T, Ojima M, et al.: Protective effects of candesartan cilexetil against stroke, kidney dysfunction, and cardiac hypertrophy in stroke-prone spontaneously hypertensive rats. Clin Exper Hypertens 1997, 19:1079–1099.

    CAS  Google Scholar 

  19. Wada T, Kamagawa R, Ishimura Y, et al.: Role of angiotensin II in cerebrovascular and renal damage in DOC acetate-salt hypertensive rats. J Hypertens 1995, 13:113–122.

    Article  PubMed  CAS  Google Scholar 

  20. Ito T, Yamakawa H, Bregonzio C, et al.: Protection against ischemia and improvement of cerebral blood flow in genetically hypertensive rats by chronic pretreatment with an angiotensin II AT1 antagonist. Stroke 2002, 33:2297–2303.

    Article  PubMed  CAS  Google Scholar 

  21. de Gasparo M, Catt K, Inagani T, et al.: International Union of Pharmacology XXIII the angiotensin II receptors. Pharmacol Rev 2000, 52:415–472. This comprehensive pharmacologic review on the angiotensin II receptor is a cornerstone in our current understanding of the renin angiotensin system.

    PubMed  Google Scholar 

  22. Llorens-Cortes C, Mendelsohn F: Organisation and functional role of the brain angiotensin system. J Renin Angiotensin Aldosterone Syst 2002, 3(Suppl 1):S39-S48.

    PubMed  Google Scholar 

  23. Unger T: The angiotensin II type 2 receptor: variations on an enigmatic theme. J Hypertens 1999, 17:1775–1786.

    Article  PubMed  CAS  Google Scholar 

  24. Culman J, Baulmann J, Blume A, Unger T: The renin-angiotensin system in the brain: an update. J Renin Angiotensin Aldosterone Syst 2001, 2:96–102. This pharmacologic review has the advantage to be exclusively focused on the brain renin-angiotensin system.

    PubMed  CAS  Google Scholar 

  25. Ardaillou R: Angiotensin receptors. J Am Soc Nephrol 1999, 10:S30-S39.

    PubMed  CAS  Google Scholar 

  26. de Paolis P, Porcellini A, Gigante B, et al.: Modulation of the AT2 subtype receptor gene activation and expression by the AT1 receptor in endothelial cells. J Hypertens 1999, 17:1873–1877.

    Article  PubMed  Google Scholar 

  27. Su JZ, Fukuda N, Jin XQ, et al.: Effect of AT2-receptor on expression of AT1 and TGF-beta receptors in VSMCs from SHR. Hypertension 2002, 40:853–858.

    Article  PubMed  CAS  Google Scholar 

  28. Jin XQ, Fukuda N, Su JZ, et al.: Angiotensin II type 2 receptor gene transfer downregulates angiotensin II type 1a receptor in vascular smooth muscle cells. Hypertension 2002, 39:1021–1027.

    Article  PubMed  CAS  Google Scholar 

  29. Albiston AL, McDowall SG, Matsacos D, et al.: Evidence that the angiotensin IV (AT(4)) receptor is the enzyme insulin-regulated aminopeptidase. J Biol Chem 2001, 276:48623–48626. An important article demonstrating that the receptor of Ang IV is actually an enzyme regulated by insulin.

    Article  PubMed  CAS  Google Scholar 

  30. Rogi T, Tsujimoto M, Nakazato H, et al.: Human placental leucine aminopeptidase/oxytocinase: a new member of type II membrane-spanning zinc metallopeptidase family. J Biol Chem 1996, 271:56–61.

    Article  PubMed  CAS  Google Scholar 

  31. Kramar E, Harding J, Wright J: Angiotensin II and IV induced changes in cerebral blood flow: roles of AT1, AT2 and AT4 receptors subtypes. Regul Pept 1997, 68:131–138.

    Article  PubMed  CAS  Google Scholar 

  32. Ferrario CM, Chappell M, Tallant A, et al.: Counterregulatory actions of angiotensin (1-7). Hypertension 1997, 30:535–541. This paper is a comprehensive review on angiotensin (1-7).

    PubMed  CAS  Google Scholar 

  33. Ferrario CM: Commentary on Tikellis et al: There is more to discover about angiotensin converting enzyme. Hypertension 2003, 41:390–391. This editorial comment puts the counterregulatory role of ACE and ACE2 into perspective.

    Article  PubMed  CAS  Google Scholar 

  34. Santos R, Simoes e Silva A, Maric C, et al.: Angiotensin (1-7) is an endogenous ligand for the G-protein-coupled receptor Mas. PNAS 2003, 100:8258–8263.

    Article  PubMed  CAS  Google Scholar 

  35. Fernandez L, Caride V, Twickler J, Galardy R: Renin-angiotensin and development of collateral circulation after renal ischemia. Am J Physiol 1982, 243:H869-H875.

    PubMed  CAS  Google Scholar 

  36. Fernandez L, Spencer D, Kaczmar T: Angiotensin II decreases mortality rate in gerbils with unilateral carotid ligation. Stroke 1986, 17:82–85.

    PubMed  CAS  Google Scholar 

  37. Achard JM, Fournier A, Mazouz H, et al.: Protection against ischemia: a physiological function of the renin angiotensin system. Biochem Pharmacol 2001, 62:261–271. This review summarizes 20 years of research by the Fernandez group on the role of angiotensin in the protection against ischemia by recruitment of collateral circulation (through non-AT1-receptor activation) or by promotion of angiogenesis (by AT1-receptor activation).

    Article  PubMed  CAS  Google Scholar 

  38. Kaliszewski C, Fernandez L, Wicke J: Differences in mortality rate between abrupt and progressive carotid ligation in the gerbil: role of endogenous angiotensin II. J Cerebral Blood Flow Metab 1988, 8:149–154.

    CAS  Google Scholar 

  39. Maktabi M, Todd M, Stachovi G: Angiotensin II contribute to cerebral vasodilation during hypoxia in the rabbit. Stroke 1995, 26:1871–1876.

    PubMed  CAS  Google Scholar 

  40. Fernandez L, Caride V, Strömberg C, et al.: Angiotensin AT2 receptor stimulation increases survival in gerbils with abrupt unilateral carotid ligation. J Cardiovasc Pharmacol 1994, 24:937–940.

    Article  PubMed  CAS  Google Scholar 

  41. Dalmay F, Mazouz H, Allard J, et al.: Non AT1-receptor-mediated protective effect of angiotensin against acute ischaemic stroke in the gerbil. J Renin Angiotensin Aldosterone Syst 2001, 2:103–106. This article is the first independent confirmation of Fernandez et al. discovery of the role of non-AT1 receptor-mediated, stroke-protective mechanisms in the gerbil.

    PubMed  CAS  Google Scholar 

  42. Makino I, Shibata K, Ohgami Y, et al.: Transient upregulation of the AT2 receptor mRNA level after global ischemia in the rat brain. Neuropeptides 1996, 30:596–601.

    Article  PubMed  CAS  Google Scholar 

  43. Dai W, Funk A, Herdegen T, et al.: Blockade of central angiotensin AT1 receptors improves neurological outcome and reduces expression of AP-1 transcription factors after focal brain ischemia in rats. Stroke 1999, 30:2391–2399.

    PubMed  CAS  Google Scholar 

  44. Blume A, Funk A, Gohlke P, et al.: AT2 receptor inhibition in the rat brain reverses the beneficial of AT1 receptor blockade on neurological outcome after focal brain ischemia [abstract]. Hypertension 2000, 36:656. Although currently available only as an abstract, this important work evidences the neuronal AT2-receptor-mediation of the brain resistance increase to anoxia (independent of a hemodynamic mechanism), conferred by intracerebroventricular preadministration of a low dose of losartan without systemic effect before mid-cerebralartery transient occlusion in the rat.

    Google Scholar 

  45. Groth W, Blume A, Gohlke P, et al.: Chronic pretreatment with candesartan improves recovery from focal cerebral ischaemia in rats. J Hypertens 2003, 11:2175–2182. This article demonstrates that the AT1-blocker candesartan, subcutaneously preadministered for 5 days before transient brain ischemia in the rat, decreases the severity of neurologic outcomes.

    Article  Google Scholar 

  46. Mies G, Olah L, Walther T: Angiotensin II receptor AT2 deletion increases ischemic injury in experimental stroke [abstract]. Stroke 2004, 35:237. This abstract evidences that AT2-receptor deletion in mice increases the ischemic injury secondary to 1-hour occlusion of the mid-cerebral artery.

    Google Scholar 

  47. Iwai M, Liu H, Chen R, et al.: Important role of angiotensin II type 2 receptor in focal cerebral ischemia induced by middle cerebral artery occlusion: study using receptor gene deficient mice [abstract]. J Hypertens 2004, 22(Suppl 1):S9. This abstract supports the findings of Mies et al. [53••], demonstrating, by Doppler technique instead of antipyrine method, that after ischemic insult, the cerebral blood flow reduction is greater in the AT2-receptor knockout mice. Furthermore, this paper evidences that preadministration of valsartan in the wild-type animal was associated with a better neurologic outcome, a smaller reduction of the cerebral blood flow, and a lower production of superoxides.

    Google Scholar 

  48. Wright J, Clemens J, Panetta J, et al.: Effects of LY231617 and angiotensin IV on ischemia-induced deficits in circular water maze and passive avoidance performance in rats. Brain Res 1996, 717:1–11.

    Article  PubMed  CAS  Google Scholar 

  49. Dalmay F, Pesteil F, Nisse Durglat S, et al.: Angiotensin IV decrease acute stroke mortality in the gerbil [abstract]. Am J Hypertens 2001, 14:81. This abstract points out for the first time that angiotensin IV can reverse the deleterious effect of preadministration of ACEI in the gerbil acute stroke model, suggesting that Ang IV might be involved in the BP-independent non-AT1-mediated protective effects on Ang II.

    Article  Google Scholar 

  50. BPLT Trialist Collaboration: Effect of different blood pressure lowering regimens on major cardiovascular events: results of prospectively designed overviews of randomized trials. Lancet 2003, 362:27–35.

    Google Scholar 

  51. Schrader J, Luders S, Kulschewski A, et al.: The ACCESS Study: evaluation of Acute Candesartan Cilexetil Therapy in Stroke Survivors. Stroke 2003, 34:1699–1703. This article gives the result of the ACCESS study, showing for the first time that a 7-day earlier administration of an antihypertensive drug of the AT1-receptor-blocker class in patients with recent stroke onset was responsible for a delayed cardiovascular beneficial effect, in spite of comparable BP-control during the 7-day randomized blinded, placebo-controlled period as well as during the open-labeled period, whereas candesartan dose was comparable in the two groups.

    Article  PubMed  Google Scholar 

  52. Cheung R, Hachinski V: The insula and cerebrogenic sudden death. Arch Neurol 2000, 57:1685–1688.

    Article  PubMed  CAS  Google Scholar 

  53. di Napoli M, Papa F: Angiotensin-converting enzyme inhibitor is associated with reduced plasma concentration of Creactive protein in patients with first-ever ischemic stroke. Stroke 2003, 34:2922.

    Article  PubMed  CAS  Google Scholar 

  54. Selim M, Savitz S, Gomes J, et al.: Effect of prior use of angiotensin-converting enzyme inhibitors on stroke severity [abstract]. Stroke 2004, 35:235.

    Google Scholar 

  55. Pitt B, Poole-Wilson A, Segal R, et al.: Effect of losartan compared with captopril on mortality in patients with symptomatic heart failure: randomized trial—The Losartan Heart Failure Survival Study ELITE II. Lancet 2000, 355:1582–1587.

    Article  PubMed  CAS  Google Scholar 

  56. Dickstein K, Kjekshus J, and the OPTIMAAL Steering Committee of the OSG: Effects of losartan and captopril on mortality and morbidity in high-risk patients after acute myocardial infarction: the OPTIMAAL randomized trial. Lancet 2002, 360:752–760.

    Article  PubMed  CAS  Google Scholar 

  57. Perry HM, Davis BR, Price T, et al.: Effect of treating isolated systolic hypertension on the risk of developing various types and subtypes of stroke. The Systolic Hypertension in the Elderly Program (SHEP) Cooperative Research Group. JAMA 2000, 284:465–471.

    Article  PubMed  Google Scholar 

  58. Fournier A, Oprisiu R, Andrejak M, et al.: Age-adjusted stroke incidence increase: Could angiotensin-AT1-receptor antagonists enhance stroke prevention? Stroke 2002, 33:881–882.

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Fournier, A., Achard, J.M., Boutitie, F. et al. Is the angiotensin ii type 2 receptor cerebroprotective?. Current Science Inc 6, 182–189 (2004). https://doi.org/10.1007/s11906-004-0067-8

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11906-004-0067-8

Keywords

Navigation