Humans ; Hypertension, Pulmonary ; metabolism ; Iron ; metabolism ; Metabolic Diseases

AIMTo study human urotensin II (hUII) expression in intrapulmonary arteries of rats with pulmonary hypertension induced by high pulmonary blood flow and explore the role of hU II in the development of pulmonary hypertension induced by left to right shunt.

METHODSAortocaval shunting was produced for 11 weeks in rats. Pulmonary artery mean pressure (PAMP) of each rat was evaluated using right cardiac catheterization. The pulmonary vascular structural changes, including the percentage of muscularized arteries of small pulmonary vessels and relative medial thickness of intra-acinar pulmonary arteries were examined. Meanwhile, the expression of hU II by pulmonary arteries was detected by immunohistochemistry.

RESULTSAfter 11-week aortocaval shunting, PAMP was significantly increased. The percentage of muscularized arteries of small pulmonary vessels and relative medial thickness of pulmonary arteries were obviously increased in shunting rats compared with controls (P < 0.01, respectively). Meanwhile, hU II expression by pulmonary artery endothelial cells and smooth muscle cells was significantly augmented in rats of shunt group, which was positively correlated with PAMP and the structural changes in pulmonary arteries.

CONCLUSIONThe up-regulation of hU II in pulmonary arteries might be involved in the development of pulmonary vascular structural remodeling and pulmonary hypertension induced by high pulmonary blood flow.

Animals ; Humans ; Hypertension, Pulmonary ; metabolism ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Pulmonary Circulation ; Rats ; Rats, Sprague-Dawley ; Urotensins ; metabolism

OBJECTIVETo investigate the dynamic expression and role of SENP1 (SUMO-specific proteases-1) in the pulmonary vascular wall of rat during the development of hypoxic pulmonary hypertension (HPH).

METHODSForty adult male Wistar rats were randomly divided into 5 groups (n = 8), and exposed to normoxia (Control group) or exposed to hypoxia for 3, 7, 14 or 21 d, respectively. The HPH models were established by normobaric intermittent hypoxia. Mean pulmonary arterial pressure (mPAP), right ventricle hypertrophy index (RVHI), and vessel morphometry were measured. Reverse transcriptase-polymerase chain reaction(RT-PCR) and in situ hybridization were used to determine the mRNA expression of SENP1. Immunohistochemistry and Western blot were used to determine the protein expression of SENP1.

RESULTSThe hypoxic rats developed pulmonary vascular remodeling in pulmonary arterioles after 7 d of hypoxia exposure. Pulmonary vascular remodeling in pulmonary arterioles significantly increased after 14 d of hypoxia. The level of mPAP in hypoxic rats increased significantly after 7 d of hypoxia, reached its peak after 14 d of hypoxic exposure. RVHI was markedly increased after 14 d of hypoxia. In situ hybridization and immunohistochemical analysis showed that SENP1 mRNA and protein were positively stained in control. SENP1 mRNA expression had little changes after exposure to hypoxia compared with the control, however, SENP1 protein expression was declined gradually after 7 d of hypoxia. The results of RT-PCR and Western blot showed that the same dynamic expression of SENP1 mRNA and protein in lung tissues of rats. Linear correlation analysis showed that SENP1 protein were negatively correlated with mPAP, pulmonary vascular remodeling index and RVHI.

CONCLUSIONUnder chronic hypoxia, SENP1 protein can be degradated. The dynamic expression of SENP1 protein may play a role in implicating in the development of HPH.

Animals ; Endopeptidases ; metabolism ; Hypertension, Pulmonary ; etiology ; metabolism ; Hypoxia ; complications ; metabolism ; Male ; Pulmonary Artery ; metabolism ; Rats ; Rats, Wistar

Humans ; Pulmonary Arterial Hypertension ; Bone Morphogenetic Protein Receptors, Type II/metabolism* ; Pedigree ; Mutation ; Familial Primary Pulmonary Hypertension

To ascertain whether connective tissue growth factor (CTGF) participates in the remodeling of pulmonary artery at the early-stage of bleomycin (BLM)-induced pulmonary fibrosis, mean pulmonary arterial pressure, the expression of type I and type III collagens, and the expression and location of CTGF in pulmonary artery and arteriole were investigated in the present study. Sprague-Dawley rats received instillation of BLM [5 mg/kg body weight, in 0.5 mL of normal saline (NS)] or instillation of the same amount of NS as control. Mean pulmonary arterial pressure was detected via a catheter in the pulmonary artery. Type I and type III collagens were examined with Sirius red staining under polarized light. CTGF expression was investigated by using immunohistochemistry, and was represented as average optical density and percentage of positive area of CTGF. The mean pulmonary arterial pressure was higher in rats on day 14 after BLM instillation [(19.5+/-2.9) mmHg] than that in the control rats [(14.8+/-1.2) mmHg] (P<0.05). The type I and type III collagens were increased both in pulmonary artery and arteriole of rats on day 14 after BLM instillation, compared with those in the control rats (P<0.05, P<0.01, respectively). The ratio of type I/III collagens in pulmonary artery was also higher in BLM-treated rats than that in the control rats (P<0.05). The values of average optical density of positive CTGF staining were increased both in pulmonary artery (0.37+/-0.02) and arteriole (0.40+/-0.03) of rats on day 14 after BLM instillation, compared with those in the control rats (artery, 0.34+/-0.01; arteriole, 0.29+/-0.01) (both P<0.05). The percentages of positive area of CTGF were higher in pulmonary artery (8.40+/-1.13) and arteriole (12.4+/-2.0) of rats on day 14 after BLM instillation than those in the control rats (artery: 1.42+/-0.63; arteriole: 1.16+/-0.34), respectively (both P<0.05). The increased positive CTGF staining areas were mainly located in the endothelium and smooth muscle layer. It is therefore concluded that CTGF expression increases in the endothelium and smooth muscle layer of pulmonary artery and arterioles during high pulmonary arterial pressure and remodeling of pulmonary artery at the early-stage of BLM-induced pulmonary fibrosis, and that the increased CTGF might be one of the mechanisms of maintenance and development of pulmonary hypertension.
Animals ; Bleomycin ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Connective Tissue Growth Factor ; metabolism ; Hypertension, Pulmonary ; Pulmonary Artery ; metabolism ; Pulmonary Fibrosis ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore potential divergent glycolytic metabolism gene changes between left and right ventricle in the monocmtaline (MCT) induced pulmonary arterial hypertension (PAH) rat model.

METHODSPAH was induced by a single subcutaneous injection of MCT (50 mg/kg) in rats. Control rats were injected with normal saline. MCT-PAH rats were randomly divided into MCT-2week, MCT-3week and MCT-4week groups (MCT-2w, 3w, 4w). At the end of study, the hemodynamics and right ventricular hypertrophy were compared among groups. The expression levels of proliferating cell nuclear antigen (PCNA) and TdT-mediated dUTP nick end labeling (TUNEL) in left and right ventricular cells were compared. The glycolytic key candidate genes expression was screened between two ventricles.

RESULTSAfter three to four weeks MCT injection, mean pulmonary arterial pressure, right ventricular systolic pressure and right ventricular hypertrophy index were all significantly increased compared to control group (all P < 0.05). Both left and right ventricular morphology and structure changes were observed in all PAH rats and were similar between left and right ventricular cells. Left and right ventricular cells increased while apoptotic cells decreased in proportion to the duration post MCT injection and the PCNA positive cells in the right ventricle were higher than in the left ventricle in rats post 3 and 4 weeks MCT injection (P < 0.05). The HK1, HK2, PDHα1 and LDHA mRNA expression in the left ventricle and LDHA mRNA expression were significantly upregulated after 4 weeks MCT injection compared to control rats (all P < 0.05). Moreover, HK1 mRNA expression in the left ventricle was significantly higher in the MCT-PAH-4w group than in MCT-PAH-3w group (P < 0.05). Immunohistochemistry analysis evidenced increasing HK1 positive cells in both left and right ventricle in proportion to MCT injection time and positive HK1 cells were significantly higher in the right ventricle than in left ventricle of MCT-PAH-3w and MCT-PAH-4w rats. Furthermore, the HK1 protein expression in left ventricular tissue form MCT-PAH-4w group and in right ventricular tissue from MCT-PAH-3w and MCT-PAH-4w groups were also significantly upregulated compared to control group (P < 0.05).

CONCLUSIONSEnergy metabolic shift occurs both in the left and right ventricles in this PAH model. Upregulated HK1 expression appeares earlier in right ventricle compared to left ventricle. Interference on right ventricular glycolysis may be a potential novel therapy target of PAH.

Animals ; Gene Expression ; Heart Ventricles ; metabolism ; Hemodynamics ; Hypertension ; Hypertension, Pulmonary ; metabolism ; Hypertrophy, Right Ventricular ; metabolism ; Lung ; Monocrotaline ; Rats

Natriuretic peptides (NPs) have been found to be useful markers in differentiating acute dyspneic patients presenting to the emergency department (ED) and emerged as potent prognostic markers for patients with congestive heart failure (CHF). The best-established and widely used clinical application of BNP and NT-proBNP testing is for the emergent diagnosis of CHF in patients presenting with acute dyspnea. Nevertheless, elevated NPs levels can be found in many circumstances involving left ventricular (LV) dysfunction or hypertrophy; right ventricular (RV) dysfunction secondary to pulmonary diseases; cardiac inflammatory or infectious diseases; endocrinology diseases and high output status without decreased LV ejection fraction. Even in the absence of significant clinical evidence of volume overload or LV dysfunction, markedly elevated NP levels can be found in patients with multiple comorbidities with a certain degree of prognostic value. Potential clinical applications of NPs are expanded accompanied by emerging reports regarding screening the presence of secondary cardiac dysfunction; monitoring the therapeutic responses, risk stratifications and providing prognostic values in many settings. Clinicians need to have expanded knowledge regarding the interpretation of elevated NPs levels and potential clinical applications of NPs. Clinicians should recognize that currently the only reasonable application for routine practice is limited to differentiation of acute dyspnea, rule-out-diagnostic-tests, monitoring of therapeutic responses and prognosis of acute or decompensated CHF. The rationales as well the potential applications of NPs in these settings are discussed in this review article.
Acute Coronary Syndrome/metabolism ; Arrhythmias, Cardiac/metabolism ; Heart Failure/*metabolism ; Humans ; Hypertension, Pulmonary/metabolism ; Natriuretic Peptides/*metabolism ; Sepsis/metabolism

AIMTo investigate the dynamic changes and functions of urotensin II (U lI) receptor (UT) in pulmonary arteries of rats chronically exposed to hypoxia-hypercapnia.

METHODSIn rats with hypoxia-hypercapnia at 1, 2 and 4 weeks U II receptor binding of pulmonary arteries sarcolemma was determined by radioligand assay. U II mRNA and UTmRNA in various grades of pulmonary arterioles were measured by in situ hybridization.

RESULTS(1) Mean pulmonary pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV + S) of 1-week group were higher than those of normal control (NC) group by 26.2% and 21.6% (P < 0.01), respectively, and 2-week group higher than 1-week group by 22.5% and 14.1% (respectively, P < 0.01). However, no significant changes were found between 4-week and 2-week group. (2) U Il receptor (Bmax) of 1-week group was higher than NC group by 38.8%, 2-week group higher than 1-week group by 23.2%, and 4-week group increased 7.3% compared with 2-week group (respectively, P < 0.01). The UT changes were time-dependent, while the affinity to U II (Kd) was no different among each group. (3) UII mRNA in each grade of pulmonary arterioles of 2-week group and 4-week group were higher than NC group (respectively, P < 0.01), and those of 2-week group were higher than 1-week group by 5.9% (P > 0.05), 16.4% and 9.1% (respectively, P < 0.01), while no differences existed between 2-week group and 4-week group. (4) UT mRNA in each grade of pulmonary arterioles of all hypoxia-hypercapnia groups was higher than NC group (respectively, P < 0.01), and those of two abaxial grade vessels in 1-week group were the highest. No differences existed between 2-week group and 4-week group. (5) The pulmonary vessels remodeling were time-dependently aggravated by hypoxia-hypercapnia.

CONCLUSIONThe dynamic changes of UT in pulmonary arterioles might have important contribution to the development of pulmonary hypertension and pulmonary arteriole remodeling induced by chronic hypoxia-hypercapnia in rats.

Animals ; Arterioles ; metabolism ; physiopathology ; Hypercapnia ; metabolism ; Hypertension, Pulmonary ; metabolism ; physiopathology ; Hypoxia ; metabolism ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; metabolism

AIMTo investigate the changes and probable roles of adrenomedullin2/intermedin (AIDM2/IMD), a novel micromolecular bioactive peptide, in the lungs of rats with chronic hypoxic pulmonary hypertension.

METHODSTwenty male SD rats were randomly divided into normal control group (NC) and normobaric hypoxia group (4H). The protein levels of ADM and ADM2/IMD) in the plasma and lung were measured by radioimmunoassay and immunohistochemistry. The mRNA expressions of ADM, ADM2/IMD and their receptors C (RLR, RAMP1, RAMP2 and RAMP3 in the lung tissue were determined by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS(1) The rat model of chronic pulmonary hypertension was confirmed by the increased mean pulmonary arterial pressure (mPAP) and weight ratio of right ventricle to left ventricle plus septum [RV/(LV + S)] in 4H group compared to NC group. (2) The concentrations of ADM in the plasma and lung homogenate of 4H group were 2.3 and 3.2 folds of NC group, respectively (all P < 0.01). The levels of ADM2/IMD were higher 89.6% and 45.0% in the plasma and lung homogenate of 4H group than those of NC group (respectively, P < 0.01, P < 0.05). (3) The mRNA expressions of ADM2/IMD and ADM in the lung of 4H group were up-regulated (respectively, P < 0.01, P < 0.05 vs. NC group). The expressions of CRLR and RAMP1 mRNAs were down-regulated (all P < 0.01 vs. NC group), while the levels of RAMP2 and RAMP3 mRNAs were no significant difference between the two groups. (4) The strong ADM2/IMD immunostaining was detected in the endothelial and adventitial cells of the rat pulmonary arteriole.

CONCLUSIONADM2/IMD, like its paralog ADM, might be closely related to the chronic hypoxic pulmonary hypertension in rats. The disorders of the gene expression and/or the synthesis and metabolism of ADM2/IMD and its receptor CRLR/RAMP1 possibly take part in the pathogenesis of chronic hypoxic pulmonary hypertension in rats.

Adrenomedullin ; metabolism ; Animals ; Hypertension, Pulmonary ; etiology ; metabolism ; Hypoxia ; complications ; metabolism ; Lung ; metabolism ; Male ; Neuropeptides ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the role of myelin and lymphocyte protein (MAL) in pulmonary hypertension (PAH). METHODS: Blood samples were collected from 50 patients with PAH (PAH group) and 50 healthy individuals for detection of plasma MAL expression using ELISA.According to the echocardiographic findings, the patients were divided into moderate/severe group (n=18) and mild group (n=32), and the correlation between MAL protein level and the severity of PAH was analyzed.In a pulmonary artery smooth muscle cell model of PAH with hypoxia-induced abnormal proliferation, the effects of mal gene knockdown and overexpression on cell growth, proliferation and starvation-induced apoptosis were observed; the changes in NK-κB signaling pathway in the transfected cells were detected to explore the molecular mechanism by which MAL regulates PAMSC proliferation and apoptosis. RESULTS: The plasma level of MAL was significantly higher in patients with PAH than in healthy individuals (P < 0.05), and the patients with moderate/severe PAH had significantly higher MAL level than those with mild PAH (P < 0.001).In PAMSCs, exposure to hypoxia significantly increased the mRNA and protein expression levels of MAL (P < 0.05), and MAL knockdown obviously inhibited hypoxia-induced proliferation and promoted starvation-induced apoptosis of the PAMSCs (P < 0.05).Knocking down mal significantly inhibited the activation of NK-κB signaling pathway that participated in regulation of PAMSC proliferation (P < 0.05). CONCLUSION The plasma level of MAL is elevated in PAH patients in positive correlation with the disease severity.MAL knockdown inhibits abnormal proliferation and promotes apoptosis of PAMSCs by targeted inhibition of the NF-κB signaling pathway to improve vascular remodeling in PAH.
Humans ; Pulmonary Artery ; Hypertension, Pulmonary ; Myelin Sheath/metabolism* ; Apoptosis ; Myocytes, Smooth Muscle ; Vascular Remodeling/genetics* ; Cell Proliferation ; Hypoxia/metabolism* ; Lymphocytes