Pulmonary hypertension due to monocrotaline pyrrole is reduced by moderate thrombocytopenia

1988 ◽  
Vol 255 (5) ◽  
pp. H1165-H1172 ◽  
Author(s):  
P. E. Ganey ◽  
K. H. Sprugel ◽  
S. M. White ◽  
J. G. Wagner ◽  
R. A. Roth

To elucidate further the role of the platelet in the development of monocrotaline pyrrole (MCTP)-induced lung injury and pulmonary hypertension, MCTP-treated rats were made thrombocytopenic by cotreatment with an anti-rat platelet serum (PAS). Lung injury was assessed from increases in lung weight, lavage fluid protein concentration, and lactate dehydrogenase activity and from accumulation in lung tissue of 125I-labeled albumin. These indexes of injury were not different in MCTP-treated rats with normal or reduced platelet numbers at day 4,8, or 14. In MCTP-treated rats not receiving the PAS, pulmonary arterial pressure was elevated by day 8. However, pulmonary arterial pressure was the same as controls at both day 8 and day 14 in MCTP-treated rats made moderately thrombocytopenic by cotreatment with PAS. More marked reduction of platelet number abolished the protective effect of thrombocytopenia against pulmonary hypertension. In a separate series of experiments, treatment with antibodies to platelet-derived growth factor (PDGF), a potential mediator in the response to MCTP-induced injury, did not protect rats from the cardiopulmonary effects of MCTP. These data indicate that moderate reduction of the number of circulating platelets prevents MCTP-induced pulmonary hypertension but not MCTP-induced lung injury, suggesting that the platelet is involved in the pulmonary hypertensive response to MCTP-induced lung injury by unknown mechanisms.

1983 ◽  
Vol 245 (2) ◽  
pp. H300-H306 ◽  
Author(s):  
L. H. Bruner ◽  
K. S. Hilliker ◽  
R. A. Roth

Chemically synthesized monocrotaline pyrrole (MCTP) was administered to adult male rats at a dose of 5 mg/kg in the tail vein. Controls received an equivalent volume of dimethylformamide vehicle. Rats were killed at 3, 5, 7, 10, and 14 days after treatment. Bronchopulmonary lavage fluid lactate dehydrogenase activity and lung weight were significantly elevated at 4 and 7 days, respectively, after MCTP, indicating that pulmonary damage had occurred. White blood cell count was elevated 7 days after treatment. Mean pulmonary arterial pressure was also first elevated in treated (22 +/- 3 mmHg) compared with control (16 +/- 1 mmHg) animals 7 days after treatment. Right ventricle-to-left ventricle plus septum weight ratios were significantly increased in treated (0.429 +/- 0.015) vs. control (0.320 +/- 0.015) animals 14 days after treatment. Development of right heart enlargement correlated with a shift in the QRS complex mean electrical axis in the frontal plane of the electrocardiogram. These results indicate that MCTP produces effects similar to that caused by monocrotaline, that pulmonary arterial pressure increases from control levels between 5 and 7 days after treatment, and that measurement of mean electrical axis of the electrocardiogram may be a useful, noninvasive method to monitor MCTP-induced cardiac changes in vivo.


1992 ◽  
Vol 72 (2) ◽  
pp. 416-422 ◽  
Author(s):  
J. M. Jacobson ◽  
J. R. Michael ◽  
R. A. Meyers ◽  
M. B. Bradley ◽  
A. M. Sciuto ◽  
...  

Exposing rabbits for 1 h to 100% O2 at 4 atm barometric pressure markedly increases the concentration of thromboxane B2 in alveolar lavage fluid [1,809 +/- 92 vs. 99 +/- 24 (SE) pg/ml, P less than 0.001], pulmonary arterial pressure (110 +/- 17 vs. 10 +/- 1 mmHg, P less than 0.001), lung weight gain (14.6 +/- 3.7 vs. 0.6 +/- 0.4 g/20 min, P less than 0.01), and transfer rates for aerosolized 99mTc-labeled diethylenetriamine pentaacetate (500 mol wt; 40 +/- 14 vs. 3 +/- 1 x 10(-3)/min, P less than 0.01) and fluorescein isothiocyanate-labeled dextran (7,000 mol wt; 10 +/- 3 vs. 1 +/- 1 x 10(-4)/min, P less than 0.01). Pretreatment with the antioxidant butylated hydroxyanisole (BHA) entirely prevents the pulmonary hypertension and lung injury. In addition, BHA blocks the increase in alveolar thromboxane B2 caused by hyperbaric O2 (10 and 45 pg/ml lavage fluid, n = 2). Combined therapy with polyethylene glycol- (PEG) conjugated superoxide dismutase (SOD) and PEG-catalase also completely eliminates the pulmonary hypertension, pulmonary edema, and increase in transfer rate for the aerosolized compounds. In contrast, combined treatment with unconjugated SOD and catalase does not reduce the pulmonary damage. Because of the striking increase in pulmonary arterial pressure to greater than 100 mmHg, we tested the hypothesis that thromboxane causes the hypertension and thus contributes to the lung injury. Indomethacin and UK 37,248–01 (4-[2-(1H-imidazol-1-yl)-ethoxy]benzoic acid hydrochloride, an inhibitor of thromboxane synthase, completely eliminate the pulmonary hypertension and edema.(ABSTRACT TRUNCATED AT 250 WORDS)


1992 ◽  
Vol 72 (4) ◽  
pp. 1235-1242 ◽  
Author(s):  
D. Wang ◽  
M. H. Li ◽  
K. Hsu ◽  
C. Y. Shen ◽  
H. I. Chen ◽  
...  

Pulmonary air embolism causes physical obstruction of microvasculature and leads to permeability changes, release of mediators, and injury to lung tissue. In this study we employed an isolated perfused rat lung model to investigate the primary and secondary effects produced by infusion of air into the pulmonary artery. Infusion of various doses of air (0.10–0.25 ml) over a 1-min period produced a dose-dependent increase in pulmonary arterial pressure and lung weight gain. In contrast, when a constant air dose was administered over various periods of time (0.25 ml over 0.5–8.0 min), the pulmonary arterial pressure rose to the same extent regardless of the infusion rate, whereas the lung weight gain increased proportionately with the rate of infusion. Total vascular resistance rose from 1.41 +/- 0.04 to 5.04 +/- 0.09 mmHg.ml-1.min in rats given 0.25 ml air over 1 min (n = 14, P less than 0.001), with greater than or equal to 90% of this increase occurring in the arterial segments. Both thromboxane B2 and endothelin concentrations also increased in the perfusate, suggesting their involvement in this increased resistance. Furthermore the pulmonary filtration coefficient increased from 0.21 +/- 0.05 to 1.28 +/- 0.26 g.min-1.cmH2O–1.100 g (n = 8, P less than 0.001), and the protein concentration in lung lavage fluid also rose, indicating lung injury. Leukocyte counts in the perfusate were unaffected by embolization, but chemiluminescent activity was increased, indicating a possible role for activated leukocytes in lung injury induced by air emboli.(ABSTRACT TRUNCATED AT 250 WORDS)


1990 ◽  
Vol 69 (1) ◽  
pp. 345-352 ◽  
Author(s):  
A. H. Stephenson ◽  
R. S. Sprague ◽  
T. E. Dahms ◽  
A. J. Lonigro

Thromboxane (Tx) has been suggested to mediate the pulmonary hypertension of phorbol myristate acetate- (PMA) induced acute lung injury. To test this hypothesis, the relationship between Tx and pulmonary arterial pressure was evaluated in a model of acute lung injury induced with PMA in pentobarbital sodium-anesthetized male mongrel dogs. Sixty minutes after administration of PMA (20 micrograms/kg iv, n = 10), TxB2 increased 10-fold from control in both systemic and pulmonary arterial blood and 8-fold in bronchoalveolar lavage (BAL) fluid. Concomitantly, pulmonary arterial pressure (Ppa) increased from 14.5 +/- 1.0 to 36.2 +/- 3.5 mmHg, and pulmonary vascular resistance (PVR) increased from 5.1 +/- 0.4 to 25.9 +/- 2.9 mmHg.l-1.min. Inhibition of Tx synthase with OKY-046 (10 mg/kg iv, n = 6) prevented the PMA-induced increase in Tx concentrations in blood and BAL fluid but did not prevent or attenuate the increase in Ppa. OKY-046 pretreatment did, however, attenuate but not prevent the increase in PVR 60 min after PMA administration. Pretreatment with the TxA2/prostaglandin H2 receptor antagonist ONO-3708 (10 micrograms.kg-1.min-1 iv, n = 7) prevented the pressor response to bolus injections of 1-10 micrograms U-46619, a Tx receptor agonist, but did not prevent or attenuate the PMA-induced increase in Ppa. ONO-3708 also attenuated but did not prevent the increase in PVR. These results suggest that Tx does not mediate the PMA-induced pulmonary hypertension but may augment the increases in PVR in this model of acute lung injury.


1984 ◽  
Vol 246 (6) ◽  
pp. H747-H753 ◽  
Author(s):  
K. S. Hilliker ◽  
T. G. Bell ◽  
D. Lorimer ◽  
R. A. Roth

Monocrotaline pyrrole (MCTP) causes lung injury, pulmonary hypertension, and right ventricular hypertrophy in rats. To determine if platelets are involved in the cardiopulmonary effects of MCTP, the response to MCTP was determined in thrombocytopenic rats. Blood platelet count was reduced to 10–20% of normal for 48 h by ip administration of an antirat platelet serum (PAS) prepared in the goat. Rats were treated iv with either MCTP 5 mg/kg or dimethylformamide vehicle and with either PAS or preimmune serum. Fourteen days after MCTP, right ventricular hypertrophy and several indexes of lung injury were measured. MCTP treatment produced right ventricular hypertrophy, increased lactate dehydrogenase activity and protein concentration in bronchopulmonary lavage fluid, increased perfusion pressure in isolated lungs, and decreased pulmonary clearance and metabolism of perfused 5-hydroxytryptamine. Thrombocytopenia did not influence the changes in these indexes of lung injury produced by MCTP in this protocol. When PAS was given 12 h before MCTP, it did not affect right ventricular hypertrophy, but when PAS treatment was begun 3 or 6 days after MCTP, right ventricular hypertrophy was decreased by 19 or 41%, respectively. These results suggest that platelets help to mediate the development of pulmonary hypertension and the hypertrophic response of the right heart following MCTP administration.


1991 ◽  
Vol 71 (5) ◽  
pp. 1990-1995 ◽  
Author(s):  
R. Burger ◽  
A. C. Bryan

Previous studies showed that repeated lung lavage leads to a severe lung injury with very poor gas exchange, a substantial protein leak into the alveoli with hyaline membrane formation, pulmonary hypertension, and migration of granulocytes (PMN) into the alveolar spaces. Depletion of PMN leads to a better gas exchange and a markedly decreased protein leak with only scanty hyaline membranes. In this study we show that there is sustained pulmonary hypertension after the lung lavage, but in PMN-depleted rabbits there is no postlavage increase in pulmonary arterial pressure. Changing the shunt fraction by manipulating mean airway pressure still leads to a hypoxic vasoconstriction with increase of pulmonary arterial pressure. Thus, after lung lavage, pulmonary reactivity to hypoxia is still preserved. Comparisons between high-frequency ventilation and conventional mechanical ventilation at the same mean airway pressures showed that equal mean airway pressure in these two very different modes of ventilation do not translate into the same mean functional lung volumes.


1987 ◽  
Vol 252 (4) ◽  
pp. H743-H748
Author(s):  
P. E. Ganey ◽  
R. A. Roth

The possible involvement of thromboxane (Tx) in the pulmonary hypertension caused by monocrotaline pyrrole (MCTP) administration to rats was investigated by pharmacological intervention of Tx synthesis and action. The cyclooxygenase inhibitor, ibuprofen, at doses that inhibited platelet function and suppressed plasma Tx levels, did not attenuate MCTP-induced right ventricular hypertrophy or increased lung weight. Dazmegrel, an inhibitor of Tx synthetase, did not affect the MCTP-induced increase in lung weight or the elevation of lactate dehydrogenase activity or protein concentration in bronchopulmonary lavage fluid, despite significant reduction of the plasma concentration of Tx. Dazmegrel also did not alter the vascular leak or right ventricular hypertrophy due to administration of MCTP to rats. Finally, the Tx receptor antagonist L-640,035 was tested using a dosing regimen that reduced the increase in right ventricular pressure caused by a stable endoperoxide analogue in MCTP-treated rats. Cotreatment with L-640,035 did not attenuate the increase in lung weight, lavage fluid lactate dehydrogenase activity or protein concentration, or the pulmonary hypertension caused by MCTP. These results indicate that interference with Tx synthesis or action does not attenuate the toxic effects of MCTP and suggest that Tx is not necessary for the cardiopulmonary response to MCTP.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Ekaterina Borodulina ◽  
Alexander M Shutov

Abstract Background and Aims An important predictor of cardiovascular mortality and morbidity in hemodialysis patients is left ventricular hypertrophy. Also, pulmonary hypertension is a risk factor for mortality and cardiovascular events in hemodialysis patients. The aim of this study was to investigate cardiac remodeling and the dynamics of pulmonary arterial pressure during a year-long hemodialysis treatment and to evaluate relationship between pulmonary arterial pressure and blood flow in arteriovenous fistula. Method Hemodialysis patients (n=88; 42 males, 46 females, mean age was 51.7±13.0 years) were studied. Echocardiography and Doppler echocardiography were performed in the beginning of hemodialysis treatment and after a year. Echocardiographic evaluation was carried out on the day after dialysis. Left ventricular mass index (LVMI) was calculated. Left ventricular ejection fraction (LVEF) was measured by the echocardiographic Simpson method. Arteriovenous fistula flow was determined by Doppler echocardiography. Pulmonary hypertension was diagnosed according to criteria of Guidelines for the diagnosis and treatment of pulmonary hypertension of the European Society of Cardiology. Results Pulmonary hypertension was diagnosed in 47 (53.4%) patients. Left ventricular hypertrophy was revealed in 71 (80.7%) patients. Only 2 (2.3%) patients had LVEF<50%. At the beginning of hemodialysis correlation was detected between systolic pulmonary arterial pressure and LVMI (r=0.52; P<0.001). Systolic pulmonary arterial pressure negatively correlated with left ventricular ejection fraction (r=-0.20; P=0.04). After a year of hemodialysis treatment LVMI decreased from 140.49±42.95 to 123.25±39.27 g/m2 (р=0.006) mainly due to a decrease in left ventricular end-diastolic dimension (from 50.23±6.48 to 45.13±5.24 mm, p=0.04) and systolic pulmonary arterial pressure decreased from 44.83±14.53 to 39.14±10.29 mmHg (р=0.002). Correlation wasn’t found between systolic pulmonary arterial pressure and arteriovenous fistula flow (r=0.17; p=0.4). Conclusion Pulmonary hypertension was diagnosed in half of patients at the beginning of hemodialysis treatment. Pulmonary hypertension in hemodialysis patients was associated with left ventricular hypertrophy, systolic left ventricular dysfunction. After a year-long hemodialysis treatment, a regress in left ventricular hypertrophy and a partial decrease in pulmonary arterial pressure were observed. There wasn’t correlation between arteriovenous fistula flow and systolic pulmonary arterial pressure.


Sign in / Sign up

Export Citation Format

Share Document