endothelin-1 and Poultry-Diseases

Pulmonary arterial hypertension is characterized by high pulmonary blood pressure, vascular remodeling and right ventricular hypertrophy. In the present study, we investigated whether genistein would prevent the development of low temperature-induced pulmonary hypertension in broilers. Hemodynamic parameters, vascular remodeling, the expression of endothelial nitric oxide and endothelin-1 content in lung tissue were evaluated. The results demonstrated that genistein significantly reduced pulmonary arterial hypertension and suppressed pulmonary arterial vascular remodeling without affecting broilers' performance. The beneficial effects appeared to be mediated by restoring endothelial function especially endothelial nitric oxide and endothelin-1, two critical vasoactive molecules that associated with the development of hypertension. Genistein supplementation might be a potential therapeutic strategy for the treatment of pulmonary hypertension.

Topics: Animals; Ascites; Chickens; Cold Temperature; Cyclic GMP; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Genistein; Hemodynamics; Hypertension, Pulmonary; Lung; Male; Neovascularization, Pathologic; Nitric Oxide Synthase Type III; Pericardial Effusion; Phytoestrogens; Poultry Diseases; Weight Gain

Four hundred 1-d-old Cobb broilers were distributed in 3 groups: group A comprised broilers maintained under natural hypobaric hypoxia (Bogotá, Colombia); group B comprised broilers under relative normoxia (Villavicencio, Colombia); and group C comprised broilers maintained at 460 m above sea level (Villavicencio, Colombia) from d 1 to 25 of age, and then moved to 2,638 m above sea level (Bogotá, Colombia). Broilers were designated as nonpulmonary hypertensive (NPHB) and pulmonary hypertensive (PHB), to estimate possible differences between them in the lung expression of endothelin 1 (ET-1) mRNA at 24 and 42 d of age. In group A, 12 NPHB and 12 PHB were used for determination of ET-1 mRNA expression at 42 d. In group B, nonPHB were found, and therefore, ET-1 mRNA expression was detected in 48 NPHB, 24 of them in each age group (24 and 42 d). In group C, only NPHB were encountered at 42 and 53 d, and ET-1 mRNA expression was determined at 42 d in 24 birds. The ET-1 mRNA levels of PHB of group A at 42 d were significantly higher than the correspondent ones in NPHB of groups A (P < 0.001) and C (P < 0.05) at the same age. No differences in ET-1 mRNA expression were encountered between NPHB of groups A and B at 42 d (P > 0.05). However, ET-1 mRNA expression was higher in group C than the correspondent one in NPHB of groups A and B at 42 d (P < 0.001). The present data suggest that ET-1 may play a major role in pulmonary hypertension pathophysiology. It is possible that chickens should be exposed to hypobaric hypoxia before d 24, as a requisite to develop pulmonary hypertension. These results might provide clues for future studies in pulmonary vasoconstriction and vascular remodeling.

Topics: Aging; Altitude; Animals; Chickens; Endothelin-1; Gene Expression Regulation; Hypertension, Pulmonary; Hypoxia; Lung; Male; Poultry Diseases; RNA, Messenger

Transforming growth factor beta (TGF β ) is a family of genes that play a key role in mediating tissue remodeling in various forms of acute and chronic lung disease. In order to assess their role on pulmonary hypertension in broilers, we determined mRNA expression of genes of the TGF β family and endothelin 1 in lung samples from 4-week-old chickens raised either under normal or cold temperature conditions. Both in control and cold-treated groups of broilers, endothelin 1 mRNA expression levels in lungs from ascitic chickens were higher than levels from healthy birds (P < 0.05), whereas levels in animals with cardiac failure were intermediate. Conversely, TGF β 2 and TGF β 3 gene expression in lungs were higher in healthy animals than in ascitic animals in both groups (P < 0.05). TGF β 1, T β RI, and T β RII mRNA gene expression among healthy, ascitic, and chickens with cardiac failure showed no differences (P > 0.05). BAMBI mRNA gene expression was lowest in birds with ascites only in the control group as compared with the values from healthy birds (P < 0.05).

Topics: Animals; Chickens; Endothelin-1; Gene Expression Regulation; Hypertension, Pulmonary; Ligands; Lung; Male; Poultry Diseases; Receptors, Transforming Growth Factor beta; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

1. Two experiments were conducted to determine if in ovo and in-feed arginine (ARG) supplementation is effective in the prevention of pulmonary hypertension syndrome (PHS) in broiler chickens reared at high altitude. 2. In Experiment I, a total of 300 fertile eggs were divided into two equal groups. On d 5 of incubation, one group was injected with 0.5 ml of ARG (20 mg/ml) and the other remained untreated and served as controls. After hatching, male chicks (64 chickens per treatment) were selected and given a commercial maize-soyabean meal diet up to 48 d of age. 3. In Experiment II, a total of 128 male broiler chickens (Ross 308) were randomly assigned to two treatments, a control group that were fed on a basal diet that met ARG requirements and the second was fed on the basal diet supplemented with 1.5 g ARG per kg of diet. 4. Cumulative mortality from ascites was recorded in both experiments. Results from Experiment I indicated that in ovo injection of ARG significantly decreased ascites mortality of broilers (18.8 vs. 43.8%). Results from Experiment II showed a similar effect so that ascites mortality in the group that were given Arg supplement was significantly lower than the control (28.1 vs. 43.8%).

Topics: Animals; Arginine; Ascites; Body Weight; Chi-Square Distribution; Chickens; Dietary Supplements; Endothelin-1; Hypertension, Pulmonary; Male; Nitric Oxide; Ovum; Poultry Diseases; Random Allocation; Thyroid Hormones

Medial hypertrophy of pulmonary arterioles during pulmonary arterial hypertension (PAH) in humans is associated with enhanced proliferation of smooth muscle cells (SMCs). Elevated matrix metalloproteinase (MMP)-2 has been found in pulmonary artery SMCs (PA-SMCs) in humans with idiopathic PAH, leading to the hypothesis that MMP-2 contributes to the proliferation and migration of vascular SMCs in the pathogenesis of PAH. Rapidly growing meat-type (broiler) chickens provide a model of spontaneous PAH. The present study was conducted to determine whether MMP-2 is involved in the medial hypertrophy of pulmonary arterioles in this model. Cultured PA-SMCs from normal birds were used to evaluate the effect of MMPs on cell proliferation. Gelatin zymography showed that endothelin (ET)-1-induced proliferation of PA-SMCs was concomitant with increased pro- and active MMP-2 production. Reverse transcription PCR demonstrated upregulation of MMP-2 mRNA. However, PA-SMC proliferation was inhibited by the MMP inhibitors doxycycline and cis-9-octadecenoyl-N-hydroxylamide. In vivo experiments revealed a significant increase of MMP-2 expression in hypertrophied pulmonary arterioles of PAH broiler chickens, which was positively correlated with wall thickness and medial hypertrophy. MMP-2 may contribute to medial hypertrophy in pulmonary arterioles during PAH in broiler chickens by enhancing the proliferation of vascular SMCs.

Topics: Animals; Arterioles; Chickens; Doxycycline; Electrophoresis, Polyacrylamide Gel; Endothelin-1; Familial Primary Pulmonary Hypertension; Gene Expression Regulation, Enzymologic; Hydroxamic Acids; Hypertension, Pulmonary; Hypertrophy; Lung; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Myocytes, Smooth Muscle; Poultry Diseases; Pulmonary Artery; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sodium Chloride

Pulmonary hypertension syndrome (PHS; ascites) in fast growing meat-type chickens (broilers) is characterized by the onset of idiopathic pulmonary arterial hypertension (IPAH) leading to right-sided congestive heart failure and terminal ascites. Intravenous microparticle (MP) injection is a tool used by poultry geneticists to screen for the broilers that are resistant (RES) or susceptible (SUS) to IPAH in a breeding population. MPs occlude pulmonary arterioles and initiate focal inflammation, causing local tissues and responding leukocytes to release vasoactive mediators such as serotonin (5-HT), endothelin-1 (ET-1), and nitric oxide (NO). RT-PCR was used to examine the differences between RES and SUS broilers in terms of gene expression of ET-1, ET receptor types A and B (ET(A) and ET(B)), the serotonin transporter (SERT), serotonin receptors (5-HT(1A), 5-HT(2A), 5-HT(1B), 5-HT(2B)), endothelial NO synthase (eNOS), and inducible NOS (iNOS) in the lungs of these broilers before (0 h) and after (2, 6, 12, 24, and 48 h) MP injection. In SUS broilers MP injection elicited higher (P < 0.05) pulmonary expression of 5-HT(1A), 5-HT(2B), and ET-1, which promote vasoconstriction and proliferation of pulmonary arterial smooth muscle cells (PASMC). In RES broilers the MP injection elicited higher expression of eNOS, iNOS, and ET(B), which promote vasodilation and inhibit PASMC proliferation. These observations support the hypothesis that the resistance of broiler chickens to IPAH may be due to the higher expression of vasoactive mediators that favor enhanced vasodilation and attenuated vasoconstriction during MP injection challenges to the pulmonary vasculature.

Topics: Animals; Chickens; Disease Susceptibility; Endothelin-1; Hypertension, Pulmonary; Injections, Intravenous; Lung; Male; Mass Screening; Microspheres; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Poultry Diseases; Pulmonary Artery; Receptors, Endothelin; Receptors, Serotonin; Serotonin; Vasoconstriction; Vasodilation

Twenty-four 1-d-old broilers were distributed in 2 groups, pulmonary hypertensive broilers (PHB) and pulmonary nonhypertensive broilers (NPHB), to estimate possible differences between them in the expression of endothelin 1 (ET-1) and its type A receptor, connective tissue growth factor, platelet-derived growth factor, and adrenomedullin expression in the lungs. For this purpose, total RNA extraction and real-time PCR analysis were used. Endothelin 1 mRNA levels in the lungs of PHB were significantly higher than the corresponding level in NPHB (P < 0.001). In contrast, the opposite was true for ET-1 type A receptor mRNA levels (P < 0.001). Connective tissue growth factor mRNA levels in the lungs of PHB were significantly higher than in the lungs of NPHB (P < 0.01). However, no differences were encountered between the 2 groups of broilers in platelet-derived growth factor mRNA expression (P > 0.05). Adrenomedullin mRNA levels in the lungs of PHB were significantly higher than in NPHB (P < 0.01). It has been demonstrated for the first time that ET-1, connective tissue growth factor, and adrenomedullin are upregulated in the lungs of PHB. Furthermore, it is suggested that these peptides may play a major role in pulmonary hypertension pathophysiology. Present data might provide clues for future research directions such as genetic selection and therapeutic intervention to revert the process of pulmonary vasoconstriction and vascular remodeling. Major research goals could be to find endothelium-derived factors that probably trigger endothelial dysfunction, as well as possible interactions with already identified molecules which also intervene in the pulmonary response to hypoxia.

Topics: Adrenomedullin; Animals; Chickens; Connective Tissue Growth Factor; Endothelin-1; Gene Expression Regulation; Hypertension, Pulmonary; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins; Lung; Male; Platelet-Derived Growth Factor; Poultry Diseases; Receptor, Endothelin A; RNA, Messenger

Under normoxic conditions in vitro, isolated pulmonary arteries from broilers exhibit reduced endothelium-dependent relaxation responses when compared with Leghorns. In vivo, hypoxia increases the susceptibility of broiler chickens to pulmonary hypertension syndrome (PHS), whereas Leghorns are considered resistant to PHS. Because L-arginine supplementation decreases the incidence of PHS in vivo and improves the relaxation responses of broiler isolated pulmonary arteries in vitro, we hypothesized that in vitro hypoxia would further reduce the relaxation responses of broilers to endothelium-derived nitric oxide (EDNO)-dependent vasodilators and that L-arginine supplementation would alleviate this impairment. As a test of this hypothesis, pulmonary arteries from broiler and Leghorn chickens were isolated and exposed to normoxia or hypoxia in the presence or absence of L-arginine while their constriction and relaxation responses to vasoactive compounds were recorded. In broilers, hypoxia did not affect the constriction responses of isolated pulmonary arteries but decreased EDNO-dependent acetylcholine-induced relaxation responses. In contrast, in Leghorns hypoxia increased endothelin-1-induced vasoconstriction responses and reduced the EDNO-dependent relaxation responses only to the lowest concentration of acetylcholine used. L-Arginine supplementation augmented the relaxation responses to acetylcholine in broilers and Leghorns under normoxia but failed to augment them under hypoxia. Relaxation responses to the NO donor, sodium nitroprusside, were not affected by hypoxia in Leghorns but were increased by hypoxia in broilers. These results suggest that the increased incidence of PHS in broiler chickens reared under hypoxia may be associated with a hypoxia-induced reduction in the synthesis or activity of EDNO in the pulmonary circulation.

Topics: Acetylcholine; Animals; Arginine; Body Weight; Chickens; Endothelin-1; Endothelium, Vascular; Heart Ventricles; Hypertension, Pulmonary; Hypoxia; Muscle Contraction; Muscle Relaxation; Muscle, Smooth, Vascular; Nitric Oxide; Nitric Oxide Donors; Nitroprusside; Organ Size; Oxygen; Potassium Chloride; Poultry Diseases; Pulmonary Artery

1. Experiments were conducted to evaluate the effect of a synthetic inhibitor of nitric oxide (NO) synthase (L-NAME) on pulmonary arterial pressure (PAP) and pulmonary hypertension syndrome (PHS) morbidity in broilers. 2. In Experiment 1, broilers were infused intravenously with L-NAME, and the mean pulmonary arterial pressure (mean PAP) and plasma NO were measured at 0, 1, 2 and 4 h after the start of infusion. The mean PAP increased and plasma NO was reduced at 1 to 2 h in broilers treated with L-NAME. 3. In Experiment 2, 180 Arbor Acres broilers were evenly divided into three groups: a control group (group C), and two groups exposed to low environmental temperatures and fed a 3, 3, 5-triiodothyronine (T3) supplemented diet alone (group A) or also including 100 ppm L-NAME (group B). 4. The PHS morbidity of group A was higher than for group C but lower than for group B. Plasma endothelin-1 was higher in broilers in groups A and B than in group C. Plasma NO was not significantly lower in broilers of group B when compared with those in group A. 5. The right/total ventricular weight ratio (RV/TV) and mean PAP were higher in groups A and B than in group C, and the RV/TV ratio increased one week earlier in group B than in group A. 6. These results suggest that L-NAME increases broiler PAP by inhibiting the endogenous synthesis of NO, leading to pulmonary hypertension, right ventricular hypertrophy and the increased morbidity of PHS in broilers.

Topics: Animals; Blood Pressure; Chickens; Dose-Response Relationship, Drug; Endothelin-1; Enzyme Inhibitors; Hypertension, Pulmonary; Incidence; Injections, Intravenous; Morbidity; NG-Nitroarginine Methyl Ester; Nitric Oxide; Poultry Diseases; Pulmonary Artery; Random Allocation; Syndrome; Vascular Resistance; Vasodilation