1. Pre-eclampsia: A Pregnancy-Induced Autoimmune Disease? Nephrology Journal Club October 28, 2008

2. Pre-eclampsia Definition: – New onset of hypertension and proteinuria after 20 weeks of gestation in a previously normotensive woman – In the setting of chronic hypertension New onset proteinuria A sudden increase in blood pressure Thrombocytopenia Elevated LFTs Diagnostic Criteria: – Hypertension Systolic Blood Pressure ≥ 140mmHg, OR Diastolic Blood Pressure ≥ 90mmHg – Proteinuria (≥ 0.3g / 24hr) 3 – 5% of pregnancies (US)

3. Severe preeclampsia: Clinical findings Systemic endothelial dysfunction / microangiopathy IUGR (small for gestational age fetuses) Target organ dysfunction – Brain  Seizures – Liver  HELLP – Kidney  Glomerular endotheliosis and proteinuria Stillman and Karumanchi. JASN 2007. 18:2281.

4. Preeclampsia: Pathophysiology Placenta Predisposing risk factors: – Family history of preeclampsia (4-fold increased risk) – Nulliparity (or prolonged inter-pregnancy interval) – Multiple gestation – Molar pregnancies – Older maternal age – Preexisting hypertension – Chronic kidney disease – DM (and increased insulin resistance) – Black race – Thrombotic vascular disease Hypoperfusion and ischemia (Page. Am J Obst Gyn 1939. 37:291.)

5. Effects of chronic RUPP on MAP Alexander et al. HTN 2000. 37:1191.

6. Effects of RUPP on renal hemodynamics Alexander et al. HTN 2000. 37:1191.

7. Pre-eclampsia: Pathophysiology Redman and Sargent. Science 2005. 308:1592.

8. Pre-eclampsia: Pathophysiology Redman and Sargent. Science 2005. 308:1592.

9. VEGF – Promoter of angiogenesis – Induces nitric oxide – Induces vasodilatory prostacyclins in endothelial cells – Glomerular healing anti-VEGF – Increase apoptosis – Impair glomerular capillary repair – Increase proteinuria (rat MPGN model) Exogenous VEGF – ↓ CyA-mediated HTN, endothelial dysfunction, and nephropathy VEGF signaling inhibitors – HTN – Proteinuria Eremina et al. Neph Physiol 2007. 106:32. Redman and Sargent. Science 2005. 308:1592.

10. Soluble fms-like tyrosine kinase 1 (sFlt1) Soluble receptor for VEGF Produced by the placenta VEGF and PlGF antagonist Increased in preeclampsia – Placental sFlt1 expression – Amniotic fluid levels Davison et al., JASN 2004. 15:2440. Redman and Sargent. Science 2005. 308:1592.

11. Excess placental sFlt1 may contribute to preeclampsia Maynard et al. JCI 2003. 111(5):649. 12

12. Impaired angiogenesis due to ↑sFlt1 in preeclampsia Maynard et al. JCI 2003. 111(5):649.

13. sFlt1 inhibits VEGF- and PlGF-induced vasodilation of renal microvessels Maynard et al. JCI 2003. 111(5):649.

14. sFlt1 response and PlGF expression pregnant nonpregnant + control Maynard et al. JCI 2003. 111(5):649.

15. sFlt1 induces glomerular endotheliosis Maynard et al. JCI 2003. 111(5):649.

17. Angiotensin II Induces sFlt1 release in pregnancy Zhou et al. Circ Res 2007. 100:88. Angiotensin II – Potent vasoconstrictor – ↑ with sFlt1 in pregnancy – May promote sFlt1 expression in pregnancy 1 2 - Human Placental Explants

18. Ang II induces the synthesis and secretion of sFlt1 by human trophoblasts via AT 1 receptor activation

19. Calcineurin signaling functions downstream of the AT 1 R to mediate Ang II-induced sFlt1 production

20. Patients with preeclampsia develop agonistic autoantibodies against the AT 1 receptor Wallukat et al. JCI 1999. 103:945. Preclamptic pts have an exaggerated pressor response to Ang II Circulating Ang II levels are not increased in preeclampsia Model  beating neonatal rat cardiomyocytes 1 2a 2b

21. Effects of IgG from preeclamptic patients 12 3 4 Wallukat et al. JCI 1999. 103:945.

22. VSMCs exposed to IgG from preeclamptic patients Wallukat et al. JCI 1999. 103:945.

23. Effect of PKC inhibition SUMMARY IgG from preeclamptic patients contains agonistic antibodies that binds the AT 1 R (second loop) Antibody subsides after delivery An AT 1 R antibody was found on VSMCs Post-receptor signaling involves PKC Wallukat et al. JCI 1999. 103:945.

24. AT 1 -AAs interact with specific sequences on second EC-loop of AT 1 receptor

25. Effects of AT 1 -AAs from preeclamptic patients AT 1 -AAs activate AT 1 R on human mesangial cells and induce IL-6 and PAI-1 secretion – Bobst et al. AJH 2005. 18:330. AT 1 -AAs cause vascular cells to express tissue factor – Dechend et al. Circulation 2000. 101:2382. AT 1 -AAs (through ↑ NADPH oxidase expression) contribute to reactive oxygen species production that may upregulate NF-  B – Dechend et al. Circulation 2003. 107:1632. AT 1 -AAs account for ↑ intracellular Ca 2+ mobilization – Thway et al. Circulation 2004. 110:1612.

28. Angiotensin receptor agonistic autoantibodies induce pre-eclampsia in pregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

29. Methods: Fig 1a-c. Injection of hIgG in pregnant mice MS = Mouse serum without injection NT = NormotensivePE = Pre-eclamptic HC = IgG Heavy chainLC = IgG Light chain Zhou et al. Nat Med 2008. 14(8):855-862.

30. Results: Fig 1d-e. BP and proteinuric effects of hIgG injection Zhou et al. Nat Med 2008. 14(8):855-862.

31. Results: Fig 2a-d. Affinity-purified AT 1 -AAs Zhou et al. Nat Med 2008. 14(8):855-862.

32. Results: Fig 2e-f. Affinity-purified AT 1 -AAs Zhou et al. Nat Med 2008. 14(8):855-862.

33. Results: Fig 3a-c. Renal Pathology – LM Zhou et al. Nat Med 2008. 14(8):855-862.

34. Results: Fig 3d. Renal Pathology – EM Zhou et al. Nat Med 2008. 14(8):855-862.

35. Results: Table S1 / Fig S1a-b. Placental and fetal weight Zhou et al. Nat Med 2008. 14(8):855-862.

36. Results: Fig S2. AT 1 -AAs induce sFlt1 and sEng production Zhou et al. Nat Med 2008. 14(8):855-862.

37. Results: Fig 4a-b. hIgG effects in nonpregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

38. Results: AT 1 -AA – mediated HTN does not require sFlt1 1d4b 2e Pregnant mice Non-pregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

39. Results: Fig 4c-d. hIgG effects in nonpregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

40. Results: AT 1 -AA – mediated proteinuria requires sFlt1 1e 4c2f Pregnant mice Non-pregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

41. Results: AT 1 -AA – mediated glomerular endotheliosis requires sFlt1 4c 3b Non-pregnant mice Pregnant mice Zhou et al. Nat Med 2008. 14(8):855-862.

42. Conclusions AT 1 -AAs (via AT 1 R activation) cause: – Elevated BP (± sFlt1) – Heavy proteinuria (+sFlt1) – Glomerular endotheliosis (+sFlt1) Placental ischemia may serve as a key stimulus for AT 1 -AA production during pregnancy AT 1 -AAs = potential therapeutic target Zhou et al. Nat Med 2008. 14(8):855-862.

43. Parikh, Karumanchi. Nat Med 2008. 14(8):810-812.