中介素在各系统的研究进展

在20世纪60年代人们就发现了降钙素基因相关肽超家族，它最初包括5个成员：降钙素（CT），胰岛淀粉样多肽（IAPP），两种降钙素基因相关肽（CGRP）和肾上腺髓质素（ADM），这些肽类激素在不同的器官和组织调节人体的动态平衡，发挥重要作用。

Effect of adrenomedullin on neuron apoptosis, infarction volume and expression of Egr-1 mRNA after focal ischemia-reperfusion in rats

Objective To observe the influence of adrenomedullin （ADM） on neuron apoptosis, infarction volume of brain, and the expression of early growth response 1 （Egr-1） mRNA in ischemia-reperfusion rats. Methods The arteria cerebri media was tied for 2 h to construct the ischemia model. Infarction volume was detected by triphenltetrazolium chloride （T＇I＇C） staining, neuronal apoptosis and necrosis was detected with terminal deoxynucleotidyl transferase nick labeling （TUNEL） method, and the Egr-1 mRNA expression was examined by in situ hybridization （ISH）. Results Infarction volume after ischemia-reperfusion is （269 ± 20） mm^3. Infarction volume after injection of ADM through different ways are femoral vein （239 ± 17） mm^3 （decreased by 11.2%）, arteria carotis （214 ± 14） mm^3 （by 20.4%） and lateral cerebral ventricle （209 ± 13） mm^3 （by 22.3%）, respectively. The results indicate that injecting ADM through arteria carotis and lateral cerebral ventricle is much more effective than it through femoral vein （P 〈 0.05）. The TUNEL-positive cells in cerebral cortex or hippocampus are few in the sham operation group, but much more in the ischemia-reperfusion group. After being supplied with ADM, especially through arteria carotis interna or lateral cerebral ventricle way, the TUNEL-positive cells decreased obviously. Expression of Egr- 1 mRNA was low in the cerebral cortex of the sham operation group rats, enhanced in the ischemia and reperfusion group rats, and enhanced markedly after treatment with ADM, especially through arteria carotis interna or lateral cerebral ventricle way （P 〈 0.01）. Conclusion Injection of ADM through different ways could alleviate neural dysfunction, decrease neuron apoptosis and brain infarction volume, and increase the expression of Egr- 1 mRNA.

Effects of continuous intermedin infusion on blood pressure and hemodynamic function in spontaneously hypertensive rats

Objective To examine the effects of exogenously administered intermedin （IMD,adrenomedullin-2） on arterial blood pressure,cardiac function and the cardiovascular IMD receptor system in spontaneously hypertensive rats （SHRs） as well as to investigate the associated mechanisms.Methods Thirteen week-old male rats were divided in Wistar Kyoto （WKY） group （n =12）,SHR group （n =12）,IMD group （SHRs infused with IMD 1-47 500 ng/kg per hour,n =12）,and ADM group （SHRs infused with adrenomedullin 500 ng/kg per hour,n =12）.Results A two-week continuous administration of low dose IMD 1-47 via mini-osmotic pumps markedly reduced blood pressure,the maximal rates of increase and decrease of left-ventricle pressure development （LV ± dp/dtmax）,left ventricular systolic pressure and heart rate in SHRs.Furthermore,IMD also inhibited protein over-expression of cardiovascular IMD receptors,myocardial Receptor Activity-Modifying Proteins （RAMP1 and RAMP2）,aortic RAMP1,RAMP2,RAMP3,and calcitonin receptor-like receptor （CRLR）;suppressed up-regulation of aortic RAMP1,RAMP2,RAMP3 and CRLR gene expression; and markedly elevated the mRNA abundance of myocardial atrial natriuretic peptide （ANP） and myocardial brain natriuretic peptide （BNP）.Additionally,IMD 1-47 administration in SHRs increased aortic cAMP concentration and reduced myocardial cAMP concentration.Conclusion These findings support the speculation that IMD,as a cardiovascular active peptide,is involved in blood pressure reduction and cardiac function amelioration during hypertension.The mechanism underlying this effect may involve IMD binding of a receptor complex formed by RAMPs and CRLR,and consequential regulation of cAMP levels and other cardiovascular active factors,such as ANP and BNP.

Effects of adrenomedullin gene overexpression on biological behavior of hepatic stellate cells

AIM: To investigate the effects of adrenomedullin (AM) gene overexpression on the biological characteristics of human hepatic stellate cells (hHSCs) by stable transfection.METHODS: hHSCs which express low basal levels of AM were stably transfected with an expression construct containing rat AM gene or with an empty expression vector. Expression of AM in hHSCs was determined by reverse transcription (RT)-polymerase chain reaction (PCR) and radioimmunoassay (RIA). Cell proliferation was evaluated by 5-bromo-2'-deoxyuridine (BrdU) incorporation and immunocytochemistry. RT-PCR and Western blot were used to test the expression of procollagen types Ⅰ and Ⅲ. Protein expressions of interstitial collagenase (MMP-1), gelatinase (MMP-2) and tissue inhibitors of matrix metalloproteinases-2 (TIMP-2) were assessed by Western blot.RESULTS: Two cell clones (A-2, A-8) transfected withthe AM gene expressed higher levels of AM mRNA (nontransfected group: 0.86±0.11, empty vector group: 1.01±0.11, A-2 clone group: 1.44±0.08 and A-8 clone group: 1.36±0.05) and protein (12.31±0.17, 12.35±0.12,12.56±0.06 and 12.62±0.07) (P＜0.05). AM geneoverexpression had inhibitory effects on cell proliferation of hHSCs (29.6%, 30.9%, 18.9% and 21.8%, respectively. P＜0.05) and expression of procollagen type Ⅰ (0.58±0.1,0.48±0.11, 0.3±0.06 and 0.31±0.07 at mRNA level)(0.27±0.07, 0.3±0.06, 0.14±0.05 and 0.13±0.05 at protein level) (P＜0.05) and procollagen type Ⅲ (0.17±0.04, 0.15±0.03, 0.1±0.02 and 0.09±0.02 at mRNA level) (0.22±0.04, 0.2±0.03, 0.11±0.04 and 0.13±0.03 at protein level) (P＜0.05). Compared with cells non-transfected (TIMp2: 2.77±0.03, MMP-2: 0.5±0.04, MMP-1: 0.49±0.07) and transfected with empty vector (TIMP2: 2.79±0.04,MMP-2: 0.48±0.03, MMP-1: 0.45±0.09), these two clones had lower expression levels of TIMP2(A-2 clone group: 2.7±0.02 and A-8 clone group: 2.71±0.02) (P＜0.05) and MMP-2(A-2 clone group: 0.15±0.05 and A-8 clone group: 0.13±0.04) (P＜0.05) but displayed a higher expression level of MMP-1(A-2 clone group: 0.68±0.06 and A-8 clone group: 0.81±0.09) (P＜0.05).CONCLUSION: AM gene exerts negative influence to some extent on hHSCs by inhibiting proliferation and production of extracellular matrix (ECM) in addition to inducing MMP-1 expression.

Expression of adrenomedullin and its receptor in lungs of rats with hypoxic pulmonary hypertension

OBJECTIVE: To 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. METHODS: We 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. RESULTS: Compared with the control group, hypoxic rats developed remarkable pulmonary hypertension, increment in the thickness of pulmonary arterioles and right ventricular hypertrophy (P

Prediction about severity and outcome of sepsis by proatrial natriuretic peptide and pro-adrenomedullin

Objective： Measurement of biomarkers is a potential approach to early prediction of the risk of mortality in patients with sepsis. The aim of the present study was to evaluate the prognostic value of pro-atrial natriuretic peptide （pro-ANP） and pro-adrenomedullin （pro- ADM） levels in a cohort of medical intensive care patients and to compare it with that of other known biomarkers and physiological scores. Methods： Blood samples of 51 consecutive critically ill patients admitted to the intensive care unit and 53 age-matched healthy control people were evaluated in this prospective study. The prognostic value ofpro-ANP and pro-ADM levels was compared with that of acute physiology and chronic health evaluation （APACHE） II scores and various biomarkers such as C-reactive protein, interleukin-6 and procalcitonin. Pro-ANP and pro-ADM were detected by a new sandwich immunoassay. Results： On admission, 25 patients had systemic inflammatory response syndrome （SIRS）, 12 sepsis, 9 severe sepsis and 5 septic shock. At that time, the median levels （ng/ml） of pro-ANP and pro-ADM were 87.22 and 0.34 respectively in patients with SIRS, 1533.30 and 2.23 in those with sepsis, 1098.73 and 4.57 in those with severe sepsis, and 1933.94 and 8.21 in those with septic shock. With the increasing severity of disease, the levels of pro- ANP and pro-ADM were gradually increased. On admission, the circulating levels ofpro-ANP and pro-ADM in patients with sepsis, severe sepsis, or septic shock were significantly higher in non-survivors than in survivors （P〈0.05）. In a receiver operating characteristic curve analysis for the survival of patients with sepsis, the areas under the curve （AUCs） for pro-ANP and pro-ADM were 0.89 and 0.87 respectively, which was similar to the AUCs for procalcitonin and APACHE II scores. Conclusion： Pro-ANP and pro-ADM are valuable biomarkers for prediction of severity of septic patients.