PULMONARY HYPERTENSION IN HIGH ALTITUDE NEWBORNS

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ALFA-HAPPOM, DECEMBER 3, 25-LYON, FRANCE

Fisiopatología del Desarrollo Programa de

1 ALFA-HAPPOM, DECEMBER 3, 25-LYON, FRANCE PULMONARY HYPERTENSION IN HIGH ALTITUDE NEWBORNS ANÍBAL LLANOS M.D. Laboratorio de Fisiología y Fisiopatología del Desarrollo Programa de Fisiopatología, ICBM, Facultad de Medicina e INCAS, UNIVERSIDAD DE CHILE.

2 ATMOSPHERIC O 2 LEVEL VS TIME

4 PAP in HIGH ALTITUDE Moore y cols, 1998

5 PPHT IN THE NEWBORN Abman, 1999

6 PULMONARY CIRCULATION TRANSITION FROM FETUS TO NEONATE Hem Modificado de Abman, 1999

7 NITRIC OXIDE (NO) Derived from L-arginina and catalyzed by NOS Three NOS isoforms : nnos (I), inos(ii) y enos(iii) enos in the blood vessels vasodilation

8 NO is an important pulmonary vasodilator 22 mmhg 2 mmhg mmhg Ross y cols, 25 Travali y Patole, 23

9 HYPOTHESIS Chronic fetal hypoxia determines pulmonary vascular hypereactivity in the neonatal period. This hypereactivity will be associated with a lesser expression/activity of the NO pathway and can be assessed as pulmonary hypertension

10 NEWBORN SHEEP PULMONARY CIRCULATION DURING ACUTE HYPOXIA- 45 a * * RNTB 5 HIPOXIA GC (ml.min -1.kg -1 ) 3 15 RNTA PAP (mmhg) Tiempo (min) RVP (mmhg.ml -1.min.kg),12,8,4 B B+I H+I R a a * * ab B B+I H+I R p<.5 : a, vs RNTB; b, vs basal; *, vs todo (dentro del grupo).

11 NEWBORN SHEEP PULMONARY CIRCULATION DURING ACUTE HYPOXIA + L-NAME PAP (mmhg) * a b L-NAME a * b b a PAP (mmhg) a NaCl O.9% a * * a ab RNTB RNTA GC (ml.min-1.kg-1) * * B B+I H+I R a L-NAME B B+I H+I R RVP (mmhg.ml-1.min.kg),3,2,1, B B+I H+I R * L-NAME b a B B+I H+I R * b a P<,5: a vs RNTB, b vs basal, * vs todos.

12 SUMMARY I THE HIGH ALTITUDE NEWBORN SHEEP PRESENTS: HIGH PULMONARY ARTERIAL PRESSURE AND RESISTANCE NITRERGIC TONE IS IMPORTANT IN THE PULMONARY CIRCULATION. NEVERTHELESS THERE IS PULMONARY HYPERTENSION CONTRACTILITY OF THE PULMONARY ARTERIES?

13 PULMONARY ARTERIES RESPONSES TO KCl p<.5 a vs RNTB Tensión, N/m N/m pd2 3, 2, 1,, 2, 1, a KCl, mm, RNTB RNTA

14 PULMONARY ARTERIES RESPONSES TO NPS p<.5 vs LLNB p<.5 a vs RNTB 1 Tensión, % K MAX 5 pd2 7,5 5, 2,5 a Log [SNP], M, RNTB RNTA

15 SUMMARY II THE HIGH ALTITUDE NEWBORN SHEEP PRESENTS: HIGHER CONTRACTILE CAPACITY HIGHER SENSITIVITY TO NPS, CONSISTENT WITH A HIGHER NITRERGIC ACTIVITY enos EXPRESSION & NOS ACTIVITY IN THE PULMONARY ARTERIES & LUNG?

16 NOS-NO PATHWAY 1 mrna enos prot enos 1,75,5,25 RNTB RNTA RNTB RNTA RNTB RNTA L-citruline formation (pmol.μ g prot -1.3 min -1 ) enos/β -actin (arbitrary units),75,5,25 a mrna enos/β -actin (arbitrary units) actividad enos prot sgc a,5,25 a sgc/β -actin (arbitrary units) RNTB RNTA Significant differences p<.5 : a, low-altitude vs high-altitude.

17 SUMMARY III THE HIGH ALTITUDE NEWBORN SHEEP PRESENTS: DECREASED enos PROTEIN EXPRESSION, HOWEVER ITS ACTIVITY IS AUGMENTED DECREASED sgc PROTEIN EXPRESSION

18 CONCLUSIONS NOS-NO HIGH ALTITUDE & PULMONARY NO - PAP & PVR (with nitrergic tone) - enos mrna = -enosprotein - enos activity - sgc protein PARTIAL COMPENSATION OF THE HIPOXIC VASOCONSTRICTION Remodelation? Vasodil/vasoconstriction?

20 NEONATAL LLAMA & SHEEP Pulmonary circulation during acute hypoxia 4 LLAMA HIPOXEMIA RNTA RNTB 4 OVEJA HIPOXEMIA 3 3 PAP (mmhg) 2 1 PAP (mmhg) TIEMPO (min) TIEMPO (min)

21 NEWBORN SHEEP NEWBORN LLAMA Herrera EA et al A. a B. 4 LASH PAP (mmhg) HASH 3 ab 2 bc 1 PAP (mmhg) b a LALL HALL PVR (mmhg.ml -1.min.Kg) C. B B + LNAME D.,3,2,1 bc B c ab a B + LNAME PVR (mmhg.ml -1.min.Kg),3,2,1 B B B + LNAME a a B + LNAME A. PAP in NB sheep with and without L-NAME, B. PAP in NB llama with and without L-NAME, C. PVR in NB sheep with and without L-NAME, D. PVR in NB llama with and without L-NAME Significant differences p<.5 : a, vs basal; b, low-altitude vs high-altitude; c, sheep vs llama (at same altitude).

22 Herrera EA et al enos/β-actin (arbitrary units) A. B. C. 1,75,5,25 1 b LASH HASH LALL HALL L-citruline formation (pmol.μg prot -1.3 min -1 ) b LASH HASH LALL HALL sgc/β-actin (arbitrary units),75,5,25 b LASH HASH LALL HALL A. Western blot of enos, B. NOS total activity, C. Western blot of sgc Significant differences p<.5 : b, low-altitude vs high-altitude ; c, sheep vs llama (at same altitude).

23 Herrera EA et al HO-1/β-actin (arbitrary units) A. B. 1,75,5,25 b b HO-2/β-actin (arbitrary units) 1,5 1,5 b b C. LASH HASH LALL LASH LASH HASH LALL HASH 5 CO production (mmolesco.min -1.ml -1 ) b,c LASH HASH LALL HALL A. Western blot of HO-1, B. Western blot of HO-2, C. CO lung production. Significant differences p<.5 : b, low-altitude vs high-altitude; c, sheep vs llama (at same altitude).

24 SHEEP & LLAMA NEWBORN PDEV mrna EXPRESSION IN PULMONARY TISSUE Unidades relatiavs (PDEV / 18S) OVTB OVEJA OVTA Unidades relatiavs (PDEV / 18S) LLTB LLAMA * LLTA OVTB: recién nacido de oveja de tierras bajas (n=5), OVTA: recién nacido de oveja de tierras altas (n=5), LLTB: recién nacido de llama de tierras bajas (n=5), LLTA: recién nacido de llama de tierras altas (n=5), p<.5 (test de Student).

25 VASODILATADOR NO-CO-cGMP MECHANISMS (+) K+ Modificado de Carvajal et al. J. Cell. Physiol., 2.

26 SUMMARY IV IN THE HIGH ALTITUDE NEWBORN LLAMA: HEM OXYGENASE-CO, APPEARS TO BE CENTRAL IN THE REGULATION OF THE PULMONARY CIRCULATION

28 Enero 24

HIGHLANDERS 25 RAQUEL RIQUELME EMILIA SANHUEZA EMILIO HERRERA ROBERTO

CARLOS BRITO MARIO MORALES GABINO LLUSCO FFDD FINANCIAMIENTO FONDECYT

EBENSPERGER NATALIA MENDEZ IRMA VALENZUELA DANIEL PEÑA EVELYN CRUZ

29 HIGHLANDERS 25 RAQUEL RIQUELME EMILIA SANHUEZA EMILIO HERRERA ROBERTO REYES GERMAN EBENSPERGER BERNARDO KRAUSE PAULA GÁLVEZ ANIBAL LLANOS CARLOS BRITO MARIO MORALES GABINO LLUSCO FFDD FINANCIAMIENTO FONDECYT & CHILE THE WELLCOME TRUST- CRIG UK RENATO EBENSPERGER NATALIA MENDEZ IRMA VALENZUELA DANIEL PEÑA EVELYN CRUZ RODRIGO ROJAS JULIAN PARER ENRIQUE VALDEZ MARK HANSON CARLOS BLANCO DINO GIUSSANI

31 PULMONARY ARTERIAL PRESSURE (PAP) IN NEWBORN SHEEP H ALONE VS H+INDOMETHACIN PAP RNOV Putre (36m) PAP RNOV Stgo (58m) 5 4 Hipoxemia Indometacina 5 4 Hipoxemia Indometacina H sola H indo PAP (mmhg) Tpo (min) Tpo (min) n=5 n=6

32 INHALATORY CO & PVR,5 PVR (mmhg ml -1 min kg -1 ),4,3,2,1 N H CO (ppm)

33 PUTRE 3,6 m SANTIAGO 58 m CHRONIC FETAL HYPOXIA FETAL NORMOXIA O 2 n HANB LANB NOS sgc NO PDE5 NOS sgc NO PDE5

34 624 mts Payachatas 633 mts

35 SYSTEMIC CIRCULATION - NEWBORN SHEEP HR (min -1 ) SAP (mmhg) SVR (mmhg.ml -1.min.Kg),4,2, * * SLSH Basal Hypoxemia Recovery HLSH Time (min) p<.5, vs basal, * vs RNTB.

36 MECANISMO VASODILATADOR NO-CO Hampl y Herget, 2

37 SYSTEM PHYSIOLOGY NEWBORN SHEEP CHRONIC INSTRUMENTATION SUPERIMPOSED ACUTE HYPOXIA - 1h BASAL - 1h HYPOXIA - 1h RECOVERY L-NAME (2 mg.kg mg.kg -1.min -1 ) MEASUREMENT OF CARDIOVASCULAR VARIABLES PAP, PcP, CARDIAC OUTPUT, SAP, HR

38 PAP & NO in High Altitude NO is a key mediator in the transition from fetus ti neonate Pulmonary NO in the chronic hypoxic neonate?

39 NEONATAL LLAMA & SHEEP Pulmonary Circulation during acute hypoxia 4 LLAMA HIPOXEMIA RNTA RNTB 4 OVEJA HIPOXEMIA 3 3 PAP (mmhg) 2 1 PAP (mmhg) TIEMPO (min) TIEMPO (min)

40 HOW THE OXYGEN IS SENSED? THE OXYGEN IS SENSED AS PO 2 CHEMORECEPTORS (e.g. carotid body, by inhibition of a potassium channel, generating an action potential traveling by the sinus nerve) In the PULMONARY ARTERY, in the ENDOTHELIUM and/or SMOOTH MUSCLE CELLS by inhibition of a potassium channel ADRENAL MEDULLA by inhibition of a potassium channel In all cells by means of the PROLYL HYDROXILASES and HIF-1

41 EX VIVO STUDIES ARTERIES 15-4 um MOUNTED ON A WIRE MYOGRAPH Optimal Diameter (KCl, 65 mm K + ) Maximal Contraction (KCl, 4, mm K + ) PHARMACOLOGIC RESPONSE SNP ( M)

42 HIPOTHESIS THE SMALL RESISTANCE ARTERIES OF THE PULMONARY CIRCULATION IN THE CHRONICALLY HYPOXIC NEWBORN SHEEP AT HIGH ALTITUDE HAVE ENHANCED CONTRACTILE RESPONSES THAN LOWLAND NEWBORN LAMBS AIM TO DETERMINE THE SMALL RESISTENCE ARTERIES RESPONSES OF THE PULMONARY CIRCULATION IN HA AND LA NB SHEEP RESPONSES ex vivo POTASSIUM CHLORIDE SNP

43 HYPOTHESIS THE EXPRESSION & ACTIVITY OF THE NITRERGIC PATHWAY IS INCREASED IN THE LUNG OF HA-NB LAMBS, AS A COMPENSATORY MECHANISM TO COPE WITH THE PULMONARY HYPERTENSION IN HIGHLANDS AIM TO DETERMINE THE mrna & PROTEIN EXPRESSION OF enos, sgc, AND NOS ACTIVITY

44 BIOCHEMISTRY & MOLECULAR BIOLOGY TISSUE OBTENTION - mrna EXPRESSION (RT-PCR) enos, PDEV vs β-actin, - PROTEIN EXPRESSION (WB) enos, sgcα vs β-actin - ACTIVITY NOS

SILDENAFIL IN PULMONARY HYPERTENSION TREATMENT: Effects in a chronic hypoxic newborn sheep. Emilio Herrera V. DMV, PhD

HAPPOM - ALFA June 26, 2007 SILDENAFIL IN PULMONARY HYPERTENSION TREATMENT: Effects in a chronic hypoxic newborn sheep. Emilio Herrera V. DMV, PhD Laboratorio de Fisiología y Fisiopatología del Desarrollo