Thromboxane inhibition reduces an early stage of chronic hypoxia-induced pulmonary hypertension in piglets

2005 ◽  
Vol 99 (2) ◽  
pp. 670-676 ◽  
Author(s):  
Candice D. Fike ◽  
Yongmei Zhang ◽  
Mark R. Kaplowitz
Keyword(s):  
Pulmonary Hypertension ◽  
Chronic Hypoxia ◽  
Early Stage ◽  
Pulmonary Arteries ◽  
Pulmonary Wedge Pressure ◽  
Thromboxane Synthase Inhibitor ◽  
Pulmonary Arterial ◽  
Synthase Inhibitor ◽  
Air Control ◽  
Arterial Responses

The pulmonary vasoconstrictor, thromboxane, may contribute to the development of pulmonary hypertension. Our objective was to determine whether a combined thromboxane synthase inhibitor-receptor antagonist, terbogrel, prevents pulmonary hypertension and the development of aberrant pulmonary arterial responses in newborn piglets exposed to 3 days of hypoxia. Piglets were maintained in room air (control) or 11% O2 (hypoxic) for 3 days. Some hypoxic piglets received terbogrel (10 mg/kg po bid). Pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output were measured in anesthetized animals. A cannulated artery technique was used to measure responses to acetylcholine. Pulmonary vascular resistance for terbogrel-treated hypoxic piglets was almost one-half the value of untreated hypoxic piglets but remained greater than values for control piglets. Dilation to acetylcholine in preconstricted pulmonary arteries was greater for terbogrel-treated hypoxic than for untreated hypoxic piglets, but it was less for pulmonary arteries from both groups of hypoxic piglets than for control piglets. Terbogrel may ameliorate pulmonary artery dysfunction and attenuate the development of chronic hypoxia-induced pulmonary hypertension in newborns.

Cyclooxygenase-2 and an early stage of chronic hypoxia-induced pulmonary hypertension in newborn pigs

2005 ◽  
Vol 98 (3) ◽  
pp. 1111-1118 ◽  
Author(s):  
Candice D. Fike ◽  
Mark R. Kaplowitz ◽  
Yongmei Zhang ◽  
Sandra L. Pfister
Keyword(s):  
Pulmonary Hypertension ◽  
Arachidonic Acid ◽  
Chronic Hypoxia ◽  
Early Stage ◽  
Pulmonary Arteries ◽  
Intact Control ◽  
Pulmonary Arterial ◽  
Cox 2 ◽  
Air Control ◽  
Arterial Responses

Our objective was to determine whether cyclooxygenase (COX)-2-dependent metabolites contribute to the altered pulmonary vascular responses that manifest in piglets with chronic hypoxia-induced pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. The effect of the COX-2 selective inhibitor NS-398 on responses to arachidonic acid or acetylcholine (ACh) was measured in endothelium-intact and denuded pulmonary arteries (100- to 400-μm diameter). Pulmonary arterial production of the stable metabolites of thromboxane and prostacyclin was assessed in the presence and absence of NS-398. Dilation to arachidonic acid was greater for intact control than for intact hypoxic arteries, was unchanged by NS-398 in intact arteries of either group, and was augmented by NS-398 in denuded hypoxic arteries. ACh responses, which were dilation in intact control arteries but constriction in intact and denuded hypoxic arteries, were diminished by NS-398 treatment of all arteries. NS-398 reduced prostacyclin production by control pulmonary arteries and reduced thromboxane production by hypoxic pulmonary arteries. COX-2-dependent contracting factors, such as thromboxane, contribute to aberrant pulmonary arterial responses in piglets exposed to 3 days of hypoxia.

Polycythemia and vascular remodeling in chronic hypoxic pulmonary hypertension in guinea pigs

1991 ◽  
Vol 71 (6) ◽  
pp. 2218-2223 ◽  
Author(s):  
S. P. Janssens ◽  
B. T. Thompson ◽  
C. R. Spence ◽  
C. A. Hales
Keyword(s):  
Pulmonary Hypertension ◽  
Guinea Pigs ◽  
Vascular Remodeling ◽  
Chronic Hypoxia ◽  
Pulmonary Arterial Pressure ◽  
Pulmonary Arteries ◽  
Similar Degree ◽  
Similar Tendency ◽  
Pulmonary Arterial ◽  
Medial Thickening

Chronic hypoxia increases pulmonary arterial pressure (PAP) as a result of vasoconstriction, polycythemia, and vascular remodeling with medial thickening. To determine whether preventing the polycythemia with repeated bleeding would diminish the pulmonary hypertension and remodeling, we compared hemodynamic and histological profiles in hypoxic bled (HB, n = 6) and hypoxic polycythemic guinea pigs (H, n = 6). After 10 days in hypoxia (10% O2), PAP was increased from 10 +/- 1 (SE) mmHg in room air controls (RA, n = 5) to 20 +/- 1 mmHg in H (P less than 0.05) but was lower in HB (15 +/- 1 mmHg, P less than 0.05 vs. H). Cardiac output and pulmonary artery vasoreactivity did not differ among groups. Total pulmonary vascular resistance increased from 0.072 +/- 0.011 mmHg.ml-1.min in RA to 0.131 mmHg.ml-1.min in H but was significantly lower in HB (0.109 +/- 0.006 mmHg.ml-1.min). Hematocrit increased with hypoxia (57 +/- 3% in H vs. 42 +/- 1% in RA, P less than 0.05), and bleeding prevented the increase (46 +/- 4% in HB, P less than 0.05 vs. H only). The proportion of thick-walled peripheral pulmonary vessels (53.2 +/- 2.9% in HB and 50.6 +/- 4.8% in H vs. 31.6 +/- 2.6% in RA, P less than 0.05) and the percent medial thickness of pulmonary arteries adjacent to alveolar ducts (7.2 +/- 0.6% in HB and 7.0 +/- 0.4% in H vs. 5.2 +/- 0.4% in RA, P less than 0.05) increased to a similar degree in both hypoxic groups. A similar tendency was present in larger bronchiolar vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonic acid metabolites and an early stage of pulmonary hypertension in chronically hypoxic newborn pigs

2003 ◽  
Vol 284 (2) ◽  
pp. L316-L323 ◽  
Author(s):  
Candice D. Fike ◽  
Mark R. Kaplowitz ◽  
Sandra L. Pfister
Keyword(s):  
Pulmonary Hypertension ◽  
Arachidonic Acid ◽  
Pulmonary Artery ◽  
Early Stage ◽  
Pulmonary Arteries ◽  
Arachidonic Acid Metabolites ◽  
Prostaglandin F ◽  
Acid Metabolites ◽  
Immunoblot Technique ◽  
Air Control

Our purpose was to determine whether production of arachidonic acid metabolites, particularly cyclooxygenase (COX) metabolites, is altered in 100–400-μm-diameter pulmonary arteries of piglets at an early stage of pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. A cannulated artery technique was used to measure responses of 100–400-μm-diameter pulmonary arteries to arachidonic acid, a prostacyclin analog, or the thromboxane mimetic U46619 . Radioimmunoassay was used to determine pulmonary artery production of thromboxane B2 (TxB2) and 6-keto-prostaglandin F1α (6-keto-PGF1α), the stable metabolites of thromboxane and prostacyclin, respectively. Assessment of abundances of COX pathway enzymes in pulmonary arteries was determined by immunoblot technique. Arachidonic acid induced less dilation in pulmonary arteries from hypoxic than in pulmonary arteries from control piglets. Pulmonary artery responses to prostacyclin and U46619 were similar for both groups. 6-Keto-PGF1αproduction was reduced, whereas TxB2 production was increased in pulmonary arteries from hypoxic piglets. Abundances of both COX-1 and prostacyclin synthase were reduced, whereas abundances of both COX-2 and thromboxane synthase were unaltered in pulmonary arteries from hypoxic piglets. At least partly due to altered abundances of COX pathway enzymes, a shift in production of arachidonic acid metabolites, away from dilators toward constrictors, may contribute to the early phase of chronic hypoxia-induced pulmonary hypertension in newborn piglets.

Progressive loss of vasodilator responsive component of pulmonary hypertension in neonatal calves exposed to 4,570 m

1993 ◽  
Vol 265 (6) ◽  
pp. H2175-H2183 ◽  
Author(s):  
A. G. Durmowicz ◽  
E. C. Orton ◽  
K. R. Stenmark
Keyword(s):  
Pulmonary Hypertension ◽  
Chronic Exposure ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Barometric Pressure ◽  
Hypoxic Conditions ◽  
Progressive Loss ◽  
Vessel Structure ◽  
Pulmonary Arterial ◽  
Neonatal Calves

Severe neonatal pulmonary hypertension (PH) may have both reversible (vasoconstrictive) and “fixed” (vasodilator unresponsive) components. To assess when and to what degree vasodilator unresponsive PH developed in the neonate, pulmonary arterial pressures (PAP) and cardiac outputs (CO) were measured, and total pulmonary resistances (TPR) were calculated in neonatal calves exposed to chronic hypoxia (CH) (barometric pressure of 430 mmHg = 4,570 m) for 1, 3, 7, and 14 days under both normoxic (barometric pressure of 640 mmHg = 1,500 m) and hypoxic conditions with and without an infusion of the vasodilator acetylcholine (ACh). Studies were done at 4 h and at 2, 4, 8, and 15 days of life in both control and CH animals. The fixed component of PH was defined as that PAP or TPR above the control baseline value which remained in CH animals after an infusion ACh at 1,500 m. Small pulmonary arteries were also examined histologically in an attempt to correlate relative changes in the reversible and fixed elements of PH with alterations in vessel structure. Chronic exposure to 4,570 m altitude prevented the normal postnatal fall in PAP and TPR observed in control animals. Instead, PAP, TPR, and the structure of small pulmonary arteries initially remained similar to those of the 4-h-old newborn. By 7 days exposure to 4,570 m, a significant element of fixed PH developed, which increased dramatically between the 7- and 14-day exposure periods and appeared to correlate with a narrowed pulmonary artery lumen and increased medial and adventitial thickness.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclooxygenase contracting factors and altered pulmonary vascular responses in chronically hypoxic newborn pigs

2002 ◽  
Vol 92 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Candice D. Fike ◽  
Sandra L. Pfister ◽  
Mark R. Kaplowitz ◽  
Jane A. Madden
Keyword(s):  
Pulmonary Hypertension ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Synthesis Inhibitor ◽  
Vascular Responses ◽  
Cox Inhibitor ◽  
Before And After ◽  
Newborn Pigs ◽  
Air Control ◽  
Constrictor Response

Pulmonary hypertension and blunted pulmonary vascular responses to ACh develop when newborn pigs are exposed to chronic hypoxia for 3 days. To determine whether a cyclooxygenase (COX)-dependent contracting factor, such as thromboxane, is involved with altered pulmonary vascular responses to ACh, newborn piglets were raised in 11% O2 (hypoxic) or room air (control) for 3 days. Small pulmonary arteries (100–400 μm diameter) were cannulated and pressurized, and their responses to ACh were measured before and after either the COX inhibitor indomethacin; a thromboxane synthesis inhibitor, dazoxiben or feregrelate; or the thromboxane-PGH2-receptor antagonist SQ-29548. In control arteries, indomethacin reversed ACh responses from dilation to constriction. In contrast, hypoxic arteries constricted to ACh before indomethacin and dilated to ACh after indomethacin. Furthermore, ACh constriction in hypoxic arteries was nearly abolished by either dazoxiben, feregrelate, or SQ-29548. These findings suggest that thromboxane is the COX-dependent contracting factor that underlies the constrictor response to ACh that develops in small pulmonary arteries of piglets exposed to 3 days of hypoxia. The early development of thromboxane-mediated constriction may contribute to the pathogenesis of chronic hypoxia-induced pulmonary hypertension in newborns.

scholarly journals Pulmonary Arterial Responses to Reactive Oxygen Species Are Altered in Newborn Piglets With Chronic Hypoxia-Induced Pulmonary Hypertension

2011 ◽  
Vol 70 (2) ◽  
pp. 136-141 ◽  
Author(s):  
Candice D Fike ◽  
Judy L Aschner ◽  
James C Slaughter ◽  
Mark R Kaplowitz ◽  
Yongmei Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pulmonary Hypertension ◽  
Chronic Hypoxia ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Newborn Piglets ◽  
Pulmonary Arterial ◽  
Arterial Responses

A Comparison of Human Pulmonary Arterial and Venous Prostacyclin and Thromboxane Synthesis- Effect of a Thromboxane Synthase Inhibitor

1984 ◽  
Vol 51 (02) ◽  
pp. 257-260 ◽  
Author(s):  
A J Carter ◽  
J A Bevan ◽  
S P Hanley ◽  
W E Morgan ◽  
D R Turner
Keyword(s):  
Thoracic Surgery ◽  
Pulmonary Arteries ◽  
Significant Inhibition ◽  
Thromboxane B2 ◽  
Thromboxane Synthase ◽  
Paired Samples ◽  
Thromboxane Synthase Inhibitor ◽  
Pulmonary Arterial ◽  
Synthase Inhibitor ◽  
Arteries And Veins

SummaryThe amounts of 6-keto-prostaglandin F1α (6-keto-PGF1α) and thromboxane B2 (TxB2) produced by the endothelial surfaces of paired samples of human pulmonary arteries and veins, obtained from patients undergoing thoracic surgery, were measured. The amounts of 6-keto-PGF1α and TxB2 produced by arteries compared with veins were not different. However, both arteries and veins produced more 6-keto-PGFlα than TxB2, the ratio being approximately 7.5:1 for both. 6-keto-PGFlα synthesis by arteries was significantly correlated with that produced by veins but the relative amounts of TxB2 were not correlated. 6-keto-PGFlα synthesis was correlated with TxB2 synthesis for veins but not for arteries. 8 of the 12 arterial samples exhibited some degree of intimal fibrosis.Incubation with the thromboxane synthase inhibitor, dazoxiben, caused a significant inhibition of vascular TxB2 synthesis and a significant increase in 6-keto-PGFlα synthesis. In 3 of the 5 cases the increase in 6-keto-PGFlα was too large to be explained by the fall in TxB2.

Effect of dietary fish oil on lung lipid profile and hypoxic pulmonary hypertension

1989 ◽  
Vol 66 (4) ◽  
pp. 1662-1673 ◽  
Author(s):  
S. L. Archer ◽  
G. J. Johnson ◽  
R. L. Gebhard ◽  
W. L. Castleman ◽  
A. S. Levine ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Fish Oil ◽  
Chronic Hypoxia ◽  
Corn Oil ◽  
Pulmonary Arteries ◽  
Hypoxic Pulmonary Hypertension ◽  
Dietary Fish ◽  
Lung Lipid ◽  
Pulmonary Arterial ◽  
Fish Oil Diet

The effects of dietary polyunsaturated fats on chronic hypoxic pulmonary hypertension were assessed in rats fed fish oil, corn oil, or a lower fat, “high-carbohydrate” diet (regular) beginning 1 mo before the start of hypoxia (0.4 atm, n = 30 for each). Mean pulmonary arterial pressures were lower in the chronically hypoxic rats fed fish oil (19.7 +/- 1.8 mm Hg) than in the rats fed corn oil (25.3 +/- 1.6 mm Hg) or regular diets (27.5 +/- 1.5 mm Hg, P less than 0.05). The fish oil diet increased lung eicosapentaenoic acid 50-fold and depleted lung arachidonic acid 60% (P less than 0.0001 for each). Lung thromboxane B2 and 6-ketoprostaglandin F1 alpha levels were lower, and platelet aggregation, in response to collagen, was reduced in rats fed fish oil. Chronically hypoxic rats fed fish oil had lower mortality rates than the other hypoxic rats. They also had lower blood viscosity, as well as less right ventricular hypertrophy and less peripheral extension of vascular smooth muscle to intra-acinar pulmonary arteries (P less than 0.05 for each). The mechanism by which dietary fish oil decreases pulmonary hypertension and vascular remodeling during chronic hypoxia remains uncertain. The finding that a fish oil diet can reduce the hemodynamic and morphological sequelae of chronic hypoxia may have therapeutic significance.

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