Pulmonary arterial pressure in fattened Angus steers at moderate altitude influences early postmortem mitochondria functionality and meat color during retail display

Author(s):  
Chaoyu Zhai ◽  
Lance C Li Puma ◽  
Adam J Chicco ◽  
Asma Omar ◽  
Robert J Delmore ◽  
...  

Abstract Pulmonary hypertension is a noninfectious disease of cattle at altitudes > 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥ 50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (< 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg; n = 5) and low (41 ± 3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 h and 48 h) and retail display (day 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2 h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48 h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 nm and 580 nm, and metmyoglobin reducing activity decreased faster (P < 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P < 0.05) in high PAP steaks but not (P > 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and a greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle, this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle. Pulmonary arterial hypertension could also decrease type I/type II muscle fiber ratio in skeletal muscle, which needs to be investigated further.

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 204-205
Author(s):  
Kathryn R Heffernan ◽  
Scott Speidel ◽  
Milt Thomas ◽  
Mark Enns ◽  
Tim Holt

Abstract Pulmonary hypertension (PH) can lead to premature mortality in fed cattle and is often called Feedlot Heart Disease (FHD). To date, pulmonary arterial pressure (PAP) has been the only indicator trait of PH that has been evaluated. The objective of this study was to evaluate relationships between heart score (using heart score as a phenotype for PH) and PAP, carcass, and feed efficiency traits in fattening Angus steers. Our hypothesis was that feed efficiency and carcass traits, along with PAP, would demonstrate a strong relationship with heart score. Feed efficiency, carcass, PAP and heart score data from 89 Black Angus steers from Colorado State University Beef Improvement Center were collected and used for this study. Evaluations were performed using a multiple linear regression model, which included heart score as a categorical fixed effect and age as a continuous fixed effect. Least Square Means, pairwise comparisons, and ANOVA tables were constructed per trait. PAP (P < 0.001) showed an important relationship to heart score and average dry matter (P < 0.10) intake approached importance to heart score. In general, feed efficiency and carcass traits decreased as heart score increased, but PAP was the only trait with a strong relationship to heart score (P < 0.05). This led us to reject our hypothesis.


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.


2021 ◽  
Vol 118 (17) ◽  
pp. e2023130118
Author(s):  
Zdravka Daneva ◽  
Corina Marziano ◽  
Matteo Ottolini ◽  
Yen-Lin Chen ◽  
Thomas M. Baker ◽  
...  

Recent studies have focused on the contribution of capillary endothelial TRPV4 channels to pulmonary pathologies, including lung edema and lung injury. However, in pulmonary hypertension (PH), small pulmonary arteries are the focus of the pathology, and endothelial TRPV4 channels in this crucial anatomy remain unexplored in PH. Here, we provide evidence that TRPV4 channels in endothelial cell caveolae maintain a low pulmonary arterial pressure under normal conditions. Moreover, the activity of caveolar TRPV4 channels is impaired in pulmonary arteries from mouse models of PH and PH patients. In PH, up-regulation of iNOS and NOX1 enzymes at endothelial cell caveolae results in the formation of the oxidant molecule peroxynitrite. Peroxynitrite, in turn, targets the structural protein caveolin-1 to reduce the activity of TRPV4 channels. These results suggest that endothelial caveolin-1–TRPV4 channel signaling lowers pulmonary arterial pressure, and impairment of endothelial caveolin-1–TRPV4 channel signaling contributes to elevated pulmonary arterial pressure in PH. Thus, inhibiting NOX1 or iNOS activity, or lowering endothelial peroxynitrite levels, may represent strategies for restoring vasodilation and pulmonary arterial pressure in PH.


1991 ◽  
Vol 261 (5) ◽  
pp. H1563-H1569 ◽  
Author(s):  
J. R. Fineman ◽  
R. Chang ◽  
S. J. Soifer

There is increasing evidence that resting pulmonary vascular tone is mediated in part by the release of endothelium-derived relaxing factors (EDRF). Because L-arginine may be a precursor for EDRF synthesis, we studied the pulmonary vasodilating effects of L-arginine at rest and during pulmonary hypertension in 16 intact newborn lambs. At rest, the intravenous infusions of L-arginine (150 mg/kg) had no hemodynamic effects. However, during pulmonary hypertension induced by hypoxia or the infusion of U-46619 (a thromboxane A2 mimic), L-arginine decreased pulmonary arterial pressure by 22 and 27%, respectively (P less than 0.05). The decrease in pulmonary arterial pressure produced by L-arginine was blocked by methylene blue, a guanylate cyclase inhibitor, and augmented by Zapranast, a guanosine 3',5'-cyclic monophosphate (cGMP) phosphodiesterase inhibitor (-17.9 vs. -31.2%, P less than 0.05). In addition, L-arginine partially reversed the pulmonary hypertension induced by N omega-nitro-L-arginine, a competitive EDRF synthesis inhibitor, but D-arginine had no hemodynamic effects. This study suggests that L-arginine produces pulmonary vasodilation by increasing cGMP concentrations, supporting the in vitro hypothesis that L-arginine is a precursor for EDRF synthesis, whose availability may become rate limiting during pulmonary hypertension.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Sakai ◽  
H Maruyama ◽  
M Ieda

Abstract Background Endothelial dysfunction is thought to be a major contributor to overall pathogenesis of vasculopathy seen in pulmonary hypertension (PH), which is manifested by the impaired release of nitric oxide (NO) generated through endothelial nitric oxide synthase (eNOS) in endothelial cells. Activation of human eNOS is regulated by phosphorylation at multiple sites including Thr33 and Ser114, which residues are followed by Pro. The peptidyl isomerase Pin1 specifically isomerizes the phospho-protein having Ser/Thr-Pro bond and regulates their activity. Pin1 is involved in proliferation, cell cycle, and apoptosis in cancer, by isomerizing some functional molecules such as JNK, JUN, cyclin D, BAX, etc. However, it is controversial whether direct interaction of Pin1 with eNOS and how eNOS activity is altered by Pin1, especially in PH. Purpose We aimed to clarify whether Pin1 contributes to the PH development using Pin1 knockout mice and Pin1 affects the expression of phosphorylated eNOS (p-eNOS) molecule and pulmonary arterial endothelial cell (PAEC) apoptosis. Methods and results Wild (WT) and Pin1-deficient mice (KO) were exposed to hypoxia (10% O2) or normoxia for 3 weeks to generate hypoxia-induced PH. Hypoxia-inducible factor (HIF1α) expression in lungs was significantly enhanced in WT-hypoxia (WH, n=6) and KO-hypoxia (KH, n=6), suggesting that hypoxic response was certainly occurred in these mice. Pulmonary arterial pressure did not elevate in KH compared with KO-normoxia (KN, n=6) and WT-normoxia (WN, n=6), it was significantly increased only in WH (P<0.01), indicating that KO did not develop PH by hypoxia. The gain of RV weight was parallel to the increase of pulmonary arterial pressure. Western blot showed that p-eNOS expression in lungs was significantly decreased in WH compared to WN, however, the expression was not different between KH and KN. It suggests that Pin1 plays a regulatory role in p-eNOS expression in hypoxic response. In cultured PAECs, the expression of p-eNOS and eNOS was markedly increased by siRNA-mediated Pin1 knockdown. Immunoprecipitation study showed the possibility of Pin1 binding to p-eNOS molecule. Apoptosis evaluated by caspase-3/7 activity by fluorescent assay and cleaved caspase-3 expression by Western blot was significantly increased by Pin1 overexpression in PAECs; however, it was significantly decreased by Pin1 knockdown. Moreover, the exaggeration of apoptosis induced by doxorubicin was markedly increased by Pin1 overexpression compared with control in PAECs; however, it was clearly suppressed by Pin1 knockdown. Conclusion This study suggests that endogenous Pin1 contributes to the development of PH partly via the dysfunction of PAECs, that is, by the interference with p-eNOS expression and by the increase of apoptosis inducibility to external stimuli. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI


1975 ◽  
Vol 38 (3) ◽  
pp. 495-498 ◽  
Author(s):  
D. H. Will ◽  
J. L. Hicks ◽  
C. S. Card ◽  
J. T. Reeves ◽  
A. F. Alexander

We investigated acute and chronic hypoxic pulmonary pressor responses in two groups of calves, one bred to be susceptible, the other resistant to high-altitude pulmonary hypertension. Twelve 5-mo-old susceptible calves residing at 1,524 m increased their mean pulmonary arterial pressure from 26 +/- 2 (SE) to 55 +/- 4 mmHg during 2 h at a simulated altitude of 4,572 m. In 10 resistant calves pressure increased from 22 +/- 1 to 37 +/- 2 mmHg. Five calves were selected from each group for further study. When 9 mo old, the 5 susceptible calves again showed a greater pressor response to acute hypoxia (27 +/- 1 to 55 +/- 4 mmHg) than did 5 resistant calves (23 +/- 1 to 41 +/- 3 mmHg). When 12 mo old, the 5 susceptible calves also developed a greater increase in pulmonary arterial pressure (21 +/- 2 to 9 +/- 4 mmHg) during 18 days at 4,572 m than did the 5 resistant calves (21 +/- 1 to 64 +/- 4 mmHg). Acute and chronic hypoxic pulmonary pressor responses were highly correlated (r = 0.91; P less than 0.001) indicating that they were probably produced through a common mechanism.


2020 ◽  
Vol 10 (3) ◽  
pp. 204589402093129
Author(s):  
Seda Tanyeri ◽  
Ozgur Y. Akbal ◽  
Berhan Keskin ◽  
Aykun Hakgor ◽  
Ali Karagoz ◽  
...  

We evaluated whether updated pulmonary hypertension definitive criteria proposed in sixth World Symposium on Pulmonary Hypertension had an impact on diagnosis of overall pulmonary hypertension and pre-capillary and combined pre- and post-capillary phenotypes as compared to those in European Society of Cardiology/European Respiratory Society 2015 pulmonary hypertension Guidelines. Study group comprised the retrospectively evaluated 1300 patients (age 53.1 ± 18.8 years, female 807, 62.1%) who underwent right heart catheterization with different indications between 2006 and 2018. Mean pulmonary arterial pressure ≥25 mmHg (European Society of Cardiology) and PAMP (mean pulmonary arterial pressure) >20 mmHg (World Symposium on Pulmonary Hypertension) right heart catheterization definitions criteria were used, respectively. For pre-capillary pulmonary hypertension, pulmonary artery wedge pressure ≤15 mmHg and pulmonary vascular resistance ≥3 Wood units criteria were included in the both definitions. Normal mean pulmonary arterial pressure (<21 mmHg), borderline mean pulmonary arterial pressure elevation (21–24 mmHg), and overt pulmonary hypertension (≥25 mmHg) were documented in 21.1, 9.8, and 69.1% of the patients, respectively. The pre-capillary and combined pre- and post-capillary pulmonary hypertension were noted in 2.9 and 1.1%, 8.7 and 2.5%, and 34.6 and 36.6% of the patients with normal mean pulmonary arterial pressure, borderline, and overt pulmonary hypertension subgroups, respectively. The World Symposium on Pulmonary Hypertension versus European Society of Cardiology/European Respiratory Society definitions resulted in a net 9.8% increase in the diagnosis of overall pulmonary hypertension whereas increases in the pre-capillary pulmonary hypertension and combined pre- and post-capillary pulmonary hypertension diagnosis were only 0.8 and 0.3%, respectively. The re-definition of mean pulmonary arterial pressure threshold seems to increase the frequency of the overall pulmonary hypertension diagnosis. However, this increase was mainly originated from those in post-capillary pulmonary hypertension subgroup whereas its impact on pre-capillary and combined pre- and post-capillary pulmonary hypertension was negligible. Moreover, criteria of pre-capillary pulmonary vascular disease and combined pre- and post-capillary phenotypes were still detectable even in the presence of normal mean pulmonary arterial pressure. The obligatory criteria of pulmonary vascular resistance ≥3 Wood units seems to keep specificity for discrimination between pre-capillary versus post-C pulmonary hypertension after lowering the definitive mean pulmonary arterial pressure threshold to 20 mmHg.


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