OBJECTIVES: To study the role of adrenomedullin (ADM) in hyperoxia-induced lung injury by examining the effect of ADM on the expression of calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein 2 (RAMP2), extracellular signal-regulated kinase (ERK), and protein kinase B (PKB) in human pulmonary microvascular endothelial cells (HPMECs) under different experimental conditions. METHODS: HPMECs were randomly divided into an air group and a hyperoxia group ( RESULTS: Compared with the air group, the hyperoxia group had significant increases in the mRNA and protein expression levels of ADM, CRLR, RAMP2, ERK1/2, and PKB ( CONCLUSIONS ERK1/2 and PKB may be the downstream targets of the ADM signaling pathway. ADM mediates the ERK/PKB signaling pathway by regulating CRLR/RAMP2 and participates in the protection of hyperoxia-induced lung injury.
Adrenomedullin/genetics* ; Endothelial Cells ; Humans ; Hyperoxia/complications* ; Lung Injury ; Receptor Activity-Modifying Proteins

In this study, reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the changes in mRNAs levels of preproadrenomedullin (ppADM) gene encoding adrenomedullin (ADM) and the essential receptor components of ADM, calcitonin receptor-like receptor (CRLR), and the receptor activity modifying protein 2 and 3 (RAMP2 and RAMP3) in the medulla oblongata, hypothalamus, midbrain, pituitary gland and adrenal gland of the stress-induced hypertensive rats. It was shown that chronic foot-shock and noise stress for 15 consecutive days induced a significant increase in systolic blood pressure (SBP) and unique changes in ppADM and its receptor components mRNAs in all areas studied. As compared with the control group, the level of ppADM mRNA, normalized against a glyceraldehydes-3-phosphate dehydrogenase (GAPDH) control, was up-regulated in the hypothalamus-pituitary-adrenal (HPA) axis, but down-regulated in the medulla oblongata and midbrain (P<0.01 and P<0.05, respectively). The relative amount of CRLR mRNA was higher in the hypothalamus than that in other areas. The level of CRLR mRNA expression was significantly increased in the medulla oblongata of the stress group (P<0.01), but decreased in the midbrain (P<0.01) as well as hypothalamus(P<0.05), as compared with that of the control group. Chronic stress for 15 consecutive days produced an increase in the level of RAMP2 mRNA expression in the medulla oblongata (P<0.01) and a decrease in the adrenal gland (P<0.01), as compared with the control. No significant stress-related changes in RAMP2 mRNA were observed in the midbrain, hypothalamus and pituitary gland. The amount of RAMP3 mRNA was relatively higher in the midbrain and hypothalamus than that in the medulla oblongata, adrenal gland and adrenal gland. Stress-induced hypertensive rats exhibited an increased RAMP3 mRNA expression in the hypothalamus and pituitary gland (P<0.01 and P<0.05, respectively) and a decrease in the adrenal gland and midbrain (P<0.05). No significant stress-related change in RAMP3 mRAN was observed in the medulla oblongata. Taken together, our results indicate that the significant changes in ppADM and its receptor components mRNAs expression in the HPA axis and autonomic centers may be related to the development of the stress-induced hypertension. Nevertheless, the pathophysiological significance of brain-derived ADM and its receptors in stress and blood pressure regulation and their roles in stress-induced hypertension still await further investigation.
Adrenomedullin ; Animals ; Brain Stem ; metabolism ; Hypertension ; etiology ; metabolism ; Hypothalamo-Hypophyseal System ; metabolism ; Male ; Peptides ; genetics ; metabolism ; Pituitary-Adrenal System ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenomedullin ; Receptors, Peptide ; biosynthesis ; genetics ; Stress, Physiological

OBJECTIVETo investigate the expression and role of adrenomedullin (ADM) and adrenomedullin receptor (ADMR) in patients with chronic obstructive pulmonary disease (COPD).

METHODSSmall pulmonary artery remodeling was observed using morphometric analysis. The expression of ADM and ADMR mRNA in lung tissue was calculated by in situ hybridization in 9 COPD cases. Cardiac catheterization was performed in 22 COPD cases to monitor changes of hemodynamic parameters and patients were divided into two groups based on mean pulmonary artery pressure (mPAP). The cases without pulmonary hypertension (PH) were placed in Group A (n = 12) and those with PH were placed in Group B (n = 10). The levels of pulmonary arterial plasma ADM were measured by radioimmunoassay. Blood gas analysis was also conducted.

RESULTSThe ratio of vascular wall thickness to external diameter (MT%) and the ratio of vascular wall area to total area (MA%) were higher in patients with COPD (P < 0.01). In situ hybridization showed that ADM mRNA and ADMR mRNA were expressed in the pulmonary artery walls of control subjects. The expression levels were significantly higher in those of COPD sufferers (P < 0.01). Statistically positive relationships were visible between ADM and ADMR, and the plasma ADM level of Group B was significantly higher than that of Group A (P < 0.05). The plasma ADM level had a significantly positive correlation to mPAP and pulmonary vascular resistance (PVR), while being negatively correlated to levels of PaO(2).

CONCLUSIONADM may play an extremely protective role as a local autocrine/paracrine factor in COPD.

Adrenomedullin ; Adult ; Aged ; Aged, 80 and over ; Female ; Hemodynamics ; Humans ; Male ; Middle Aged ; Oxygen ; blood ; Peptides ; blood ; genetics ; physiology ; Pulmonary Disease, Chronic Obstructive ; prevention & control ; RNA, Messenger ; analysis ; Receptors, Adrenomedullin ; Receptors, Peptide ; genetics ; physiology

OBJECTIVETo investigate the role of adrenomedullin (AM) in the development of hypoxic pulmonary hypertension (HPH), and to assess the expression of AM and adrenomedullin receptor (AMR) in the lungs of rats with HPH.

METHODSWe exposed 10 rats to normobaric hypoxic conditions for 3 weeks to establish rat model of pulmonary hypertension; and 10 other rats were used as normoxic controls. Mean pulmonary arterial pressure (mPAP) was measured by a right cardiac catheterization. The thickness of pulmonary arterioles was measured by a computerized image analyzer. We used the reverse transcription-polymerase chain reaction (RT-PCR) to assess the change of expression of AM and AMR in lung of HPH rat model.

RESULTSCompared with the control group, hypoxic rats developed remarkable pulmonary hypertension, increment in the thickness of pulmonary arterioles and right ventricular hypertrophy (P < 0.01). Chronic hypoxia elicited a considerable increment in expression of AM and AMR in the lungs of rats, and the ratio of AM/beta-actin and AMR/beta-actin in lungs of rats treated with hypoxia were significantly higher (P < 0.01).

CONCLUSIONSThe AM plays an important role in regulating pulmonary vascular tone and can ameliorate the development of hypoxic pulmonary hypertension in rats.

Adrenomedullin ; Animals ; Arterioles ; pathology ; Gene Expression ; Hypertension, Pulmonary ; metabolism ; pathology ; Hypertrophy, Right Ventricular ; etiology ; Hypoxia ; metabolism ; pathology ; Lung ; metabolism ; Male ; Peptides ; genetics ; Rats ; Rats, Wistar ; Receptors, Adrenomedullin ; Receptors, Peptide ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVEThe mechanism of high pulmonary blood flow-induced pulmonary hypertension remains unclear. The aim of this study was to explore the effect of proadrenomedullin N-terminal 20-peptide (PAMP) on pulmonary hypertension, through examining the alterations of pulmonary PAMP expression and plasma PAMP concentration in rats with pulmonary hypertension induced by high pulmonary blood flow.

METHODSSixteen male Sprague-Dawley rats were randomly divided into control (n=8) and shunt groups (n=8). Aortocaval shunting was produced in the shunt group. After 11 weeks of shunting, systolic pulmonary artery pressure (sPAP), diastolic pulmonary artery pressure (dPAP) and mean pulmonary artery pressure (mPAP) were evaluated by using a right cardiac catheterization procedure. The ultrastructural changes in intra-acinar pulmonary arteries were observed. The concentration of plasma PAMP was measured by radioimmunoassay. The expression of PAMP in pulmonary arteries was detected by immunohistochemical assay.

RESULTSsPAP, dPAP and mPAP were significantly increased in shunt rats compared with controls (P < 0.01). Ultrastructural changes, such as hyperplasia and swelling of endothelial cells, irregularity of internal elastic laminar, and hypertrophy and increased number of synthetic phenotype of smooth muscle cells, were found in intra-acinar pulmonary muscularized arteries in the shunt group. Plasma PAMP concentration (616 +/- 195 pg /mL vs 427 +/- 90 pg /mL) and PAMP expression in endothelial cells (0.62 +/- 0.09 vs 0.38 +/- 0.12) and in smooth muscle cells (0.24 +/- 0.07 vs 0.14 +/- 0.05) of pulmonary arteries increased significantly in the shut group compared with controls.

CONCLUSIONSThe up-regulation of pulmonary and plasm PAMP expression might be involved in the development of high pulmonary blood flow-induced pulmonary hypertension.

Adrenomedullin ; blood ; genetics ; Animals ; Hypertension, Pulmonary ; blood ; etiology ; pathology ; Male ; Pulmonary Artery ; ultrastructure ; Pulmonary Circulation ; Rats ; Rats, Sprague-Dawley

The newly discovered endogenous vasodilating and diuretic peptide adrenomedullin (AM) was considered to be of attractive value in clinical treatment of hypertension and congestive heart failure. In order to explore the treatment of cardiovascular diseases by expressing AM in vivo, AM cDNA was inserted into mammalian expressing vector pcDNA3.1, and in vitro expression of AM was carried out in cultured K(562) cell line. AM mRNA was amplified by RT-PCR from the total RNA isolated from the adrenal glands of rats and was inserted into pcDNA3.1 vector to form pcDNA3.1AM, the recombinant pcDNA3.1AM was then transferred into cultured K(562) cell line by liposome. The expression of AM in pcDNA3.1AM transferred cell was identified by RT-PCR and dot immunoblot assay. The results demonstrated that there were AM mRNA in the pcDNA3.1AM-transferred K(562) cell line and AM peptides in the culturing medium, indicating that the recombinant pcDNA3.1AM vector can express AM in mammalian cell line.
Adrenomedullin ; biosynthesis ; genetics ; Animals ; Genetic Vectors ; genetics ; Humans ; K562 Cells ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Real-Time Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection

OBJECTIVETo investigate the differential expression of adrenomedullin (ADM) in the placentas of women with normal and preeclamptic pregnancies, and explore the importance of ADM and its signal pathway in the development of preeclampsia.

METHODSTen pregnant women complicated with preeclampsia during the late term(>or=35 wk) were selected for this study along with 7 normal control pregnant women (>or=39 wk). The total RNA was extracted and sections of fresh placental tissues were prepared, and ADM expressions at mRNA and protein levels in women with normal and preeclamptic pregnancies were determined by Northern blotting and immunohistochemistry, respectively.

RESULT AND CONCLUSIONAt both mRNA and protein levels, the expression of ADM in the placentas of preeclamptic women was significantly reduced obviously as compared with that of the normal control (P<0.05), suggesting that ADM expression reduction in preeclamptic placenta might be associated with the development of preeclampsia.

Adrenomedullin ; biosynthesis ; genetics ; Adult ; Blotting, Northern ; Female ; Gene Expression Profiling ; Humans ; Immunohistochemistry ; Placenta ; metabolism ; Pre-Eclampsia ; genetics ; metabolism ; Pregnancy ; RNA, Messenger ; biosynthesis ; genetics

In this study, we observed the levels of adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) in myocardium and aorta of spontaneously hypertensive rats (SHRs) in comparison with Wistar-kyoto (WKY) rats. Contents of ADM and PAMP were measured by radioimmunoassay (RIA) in plasma, myocardium and aorta. The amount of Pro-ADM mRNA of myocardium and aorta was determined by competitive quantitative reverse transcription polymerase chain reaction (RT-PCR). In SHRs the amounts of Pro-ADM mRNA of myocardium and aorta were 66.7% (P<0.01) and 73% (P<0.01) higher than those in WKY rat, respectively. In SHRs, the levels of ADM in plasma, myocardium and aorta were 29%, 76.7% and 79% (all P<0.01) higher than those in WKY rats, respectively. The level of PAMP in SHRs was increased by 42.5% in plasma (P<0.01), 47.2% in myocardium (P<0.0.1) and 27.3% in aorta (P<0.05) compared to WKY rats, respectively. In addition, the ratio of ADM content to PAMP content in SHRs group was increased compared with that in WKY group (2.0+/-0.25 vs 1.64+/-0.3 and 2.2+/-0.18 vs 1.56+/-0.28, in myocardium and aorta, respectively, P<0.01). These results suggest that ProADM gene expression is up-regulated and the increase in ADM and PAMP is different in SHRs. The significance of inconsistency of increase in ADM and PAMP in SHRs needs to be further investigated.
Adrenomedullin ; genetics ; metabolism ; Animals ; Aorta ; metabolism ; Female ; Male ; Myocardium ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Up-Regulation

OBJECTIVETo investigate the expression of human adrenomedullin (ADM) and its receptor-receptor activity modifying protein 2/calcitonin receptor-like receptor (RAMP2/CRLR) mRNA in the tissues of normal adrenal medulla and pheochromocytoma.

METHODSTotal RNA was extracted from normal adrenal medulla and pheochromocytomas. The expression of ADM and RAMP2/CRLR mRNA were studied by reverse transcription-polymerase chain reaction. The ratios of ADM/GAPDH, RAMP2/ GAPDH, CRLR/GAPDH were used to evaluate the expression levels of ADM, RAMP2 and CRLR mRNA.

RESULTSExpressions of ADM and its receptor- RAMP2/CRLR mRNA were detected in normal adrenal medulla and pheochromocytoma tissues. ADM/GAPDH were 0.48+/-0.09 and 0.75+/-0.24, RAMP2/ GAPDH 0.79+/-0.12 and 1.29+/-0.30, CRLR/GAPDH 0.40+/-0.08 and 0.87+/-0.22 in normal adrenal medulla and pheochromocytomas, respectively (P < 0.05).

CONCLUSIONADM exerts a possible autocrine or paracrine effect in the adrenal. ADM may be involved in the pathogenesis of pheochromocytoma.

Adrenal Gland Neoplasms ; metabolism ; Adrenal Medulla ; metabolism ; Adrenomedullin ; Adult ; Calcitonin Gene-Related Peptide ; biosynthesis ; genetics ; Female ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; Male ; Membrane Proteins ; biosynthesis ; genetics ; Middle Aged ; Peptides ; genetics ; metabolism ; Pheochromocytoma ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Receptor Activity-Modifying Protein 2 ; Receptor Activity-Modifying Proteins ; Receptors, Adrenomedullin ; Receptors, Calcitonin ; biosynthesis ; genetics ; Receptors, Peptide ; metabolism

OBJECTIVETo detect the correlation between the microsatellite DNA polymorphism of adrenomedullin(ADM) gene (repeated sequences of CA) and the atherosclerotic cerebral infarction (ACI).

METHODSWith PCR, ADM genotype was monitored from 189 normotensive subjects and 283 cerebral infarction patients. By using radioimmunoassay, their plasma ADM concentration was measured, so as the biochemical index.

RESULTSThe genotype distribution of ADM between the health control and ACI groups was significantly different, chi square was 28.732, P < 0.05. As one of the four alleles, including 11, 13, 14 and 19 alleles, the frequency of 19 allele in ACI groups was much higher than that in the health control group, chi square was 26.929, P < 0.05. However, there was no significant difference in plasma ADM concentration among the different genotypes of the ACI patients.

CONCLUSIONMicrosatellite DNA polymorphism of ADM gene may be associated with the genetic predisposition to ACI.

Adrenomedullin ; genetics ; Adult ; Aged ; Alleles ; Case-Control Studies ; Cerebral Infarction ; complications ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Intracranial Arteriosclerosis ; complications ; genetics ; Male ; Microsatellite Repeats ; genetics ; Middle Aged ; Polymorphism, Genetic