Plasma concentrations of adrenomedullin and natriuretic peptides in patients with essential hypertension

Transcription

1 EXPERIMENTAL AND THERAPEUTIC MEDICINE 9: , 2015 Plsm concentrtions of drenomedullin nd ntriuretic peptides in ptients with essentil hypertension WEI HU 1*, PANG HU ZHOU 2*, XIAO BIN ZHANG 1, CHANG GENG XU 1 nd WEI WANG 1 Deprtments of 1 Urology nd 2 Orthopedics, Renmin Hospitl of Wuhn University, Wuhn, Hubei , P.R. Chin Received June 18, 2014; Accepted Februry 16, 2015 DOI: /etm Abstrct. This study ws designed to ssess ny chnges in the plsm concentrtions of drenomedullin (ADM) nd tril nd brin ntriuretic peptide (ANP nd BNP, respectively), nd to investigte their pthophysiologicl roles in ptients with essentil hypertension (EH). The plsm ADM, ANP nd BNP concentrtions were mesured in 64 ptients with untreted EH nd 35 normotensive control subjects. After 4 weeks of effective ntihypertensive therpy with orl drugs for the hypertensive ptients, the plsm concentrtions of ADM, ANP nd BNP in the hypertensive ptients were mesured gin. The plsm concentrtions of ADM, ANP nd BNP were significntly higher in the hypertensive ptients thn those in the control subjects, nd the concentrtions incresed with the clinicl stge. Furthermore, the hypertensive ptients exhibited incresed men rteril pressure (MAP), blood ure nitrogen (BUN), serum cretinine (Scr) nd decresed glomerulr filtrtion rtes (GFRs) compred with the control subjects. The plsm ADM concentrtion ws not only correlted with BUN, Scr nd the GFR, but ws lso ssocited with the MAP nd the plsm levels of ANP nd BNP. Following effective ntihypertensive therpy with orl mediction for 4 weeks, the plsm concentrtions of ADM, ANP nd BNP were significntly, but not shrply, decresed. In conclusion, ADM, long with ANP nd BNP, my be involved in the mechnisms cting ginst further increse in blood pressure nd my be useful biomrkers for the dignosis nd tretment of hypertensive ptients. Correspondence to: Professor Xio Bin Zhng, Deprtment of Urology, Renmin Hospitl of Wuhn University, 238 Libertion Rod, Wuhn, Hubei , P.R. Chin E mil: zhngxiobin_bc@163.com * Contributed eqully Key words: drenomedullin, tril ntriuretic peptide, brin ntriuretic peptide, essentil hypertension Introduction Adrenomedullin (ADM) ws originlly discovered in 1993 by Kitmur et l (1) following its isoltion from humn pheochromocytom tissue. It hs since been demonstrted tht ADM cn be synthesized by numerous mmmlin tissues, including the drenl medull, endothelil nd vsculr smooth muscle cells, myocrdium nd centrl nervous system (2,3). ADM hs diverse nd profound effects on cellulr prolifertion, contrctility, migrtion nd interction with other neurohormonl fctors, including tril nd brin ntriuretic peptide (ANP nd BNP, respectively) (4). The most importnt nd known pthophysiologicl role of ADM is tht it is potent vsorelxnt nd ntriuretic peptide (5 7). ADM dministered through intrvenous infusion hs been shown to lower blood pressure (BP) nd increse the hert rte nd crdic output (8). A direct crdiostimultory effect hs lso been found in the isolted perfused rt hert (9). The ntriuretic peptide system consists of group of neurohormones, including ANP nd BNP (10). ANP nd BNP re crdic hormones believed to ct ginst the elevtion of blood pressure nd retention of body fluid in crdiovsculr diseses, such s hypertension nd hert filure, through their vsorelxnt nd ntriuretic effects (5). ADM exerts its chief biologicl ctions vi n ccumultion of intrcellulr cyclic denosine monophosphte (11), while severl of the ctions of ANP nd BNP re medited by cyclic gunosine monophosphte (10). Since the ctions of ADM re similr to those of ANP nd BNP, despite differences in their intrcellulr signling systems, we hypothesized tht ADM functions long with ANP nd BNP to ct ginst further elevtion of blood pressure in hypertensive ptients. In the present study, the pthophysiologicl roles of ADM, ANP nd BNP in essentil hypertension (EH) were investigted by monitoring ny chnges in the plsm concentrtions of these peptides in untreted hypertensive ptients whose disese ws clssified into one of three stges. These results were then compred with those of the control subjects, nd comprisons were dditionlly mde mong the three disese stge groups. After 4 weeks of effective ntihypertensive therpy for the hypertensive ptients, the ADM, ANP nd BNP levels were re mesured. These results were then compred with the pretherpy results nd those of the control subjects.

2 1902 HU et l: PLASMA CONCENTRATIONS OF ADM AND NATRIURETIC PEPTIDES IN PATIENTS WITH EH Mterils nd methods Study subjects. Between August 2010 nd December 2012, 64 ptients with estblished EH nd 35 normotensive control subjects were recruited for this study in the Renmin Hospitl of Wuhn University (Wuhn, Chin). All subjects greed with the im of the study nd gve their informed consent prior to their inclusion in the study. The study ws pproved by the Ethics Committee of Renmin Hospitl of Wuhn University. Routine lbortory studies of the ptients included routine blood tests; urinlysis; prothrombin time, ctivted prtil thromboplstin time, fibrinogen nd D Dimer concentrtions; serum electrolytes, serum cretinine (Scr), blood ure nitrogen (BUN) nd fsting blood glucose levels; liver function tests; plsm renin ctivity, ldosterone, ctecholmine, cortisol nd thyroid hormone levels; chest roentgenogrm; n electrocrdiogrm; B scn ultrsonogrphy of the liver, cholecyst, pncres, spleen, bilterl kidneys nd drenl glnds; nd n excretory urogrm or renl rteriogrm. The glomerulr filtrtion rte (GFR) ws clculted by endogenous cysttin C clernce, s previously described (12). On the bsis of ll results nd guidelines from the World Helth Orgniztion (2003) (13), subjects were plced into dignostic ctegory. Norml BP ws defined s systolic pressure <140 mmhg nd distolic pressure <90 mmhg. Stge Ⅰ hypertension ws defined s systolic pressure 140 mmhg but <160 mmhg or distolic pressure 90 mmhg but <100 mmhg, or both. Stge Ⅱ hypertension ws defined s systolic pressure 160 mmhg but <180 mmhg or distolic pressure 100 mmhg but <110 mmhg, or both. Stge Ⅲ hypertension ws defined s systolic pressure 180 mmhg or distolic pressure 110 mmhg, or both. Secondry hypertension ws excluded by clinicl history, physicl exmintion, routine lbortory tests nd imging exmintions. None of the ptients hd clinicl evidence of crdic or heptic filure, dibetes, pulmonry disese, ngin pectoris, myocrdil infrction or other diseses tht could cuse secondry hypertension. The hypertensive ptients either hd no history of ntihypertensive tretment or hd cesed their ntihypertensive tretment 4 weeks previously. The normotensive controls were ge nd gender mtched helthy subjects who hd been hospitlized for helthy checkup. Following the initil evlution, the plsm concentrtions of ADM, ANP nd BNP were determined. A totl of 64 ptients with EH then commenced ntihypertensive therpy with one or more of the following drugs: Nifedipine, metoprolol or benzepril. After 4 weeks of effective ntihypertensive therpy, the BP of the hypertensive ptients ws normlized. The plsm levels of the three peptides were then re mesured. Arteril BP ws mesured by mercury sphygmomnometer once the ptients hd rested in seted position for 30 min in quiet nd wrm room without smoking or drinking coffee. The men of three BP mesurements t 5 min intervls ws used to clssify the subjects. Preprtions of humn ADM (hadm), ANP nd BNP. Blood smples were drwn from n ntecubitl vein erly in the morning following n overnight fst nd were trnsferred to ice chilled tubes contining protinin (500 KIU/ml) nd EDTA (1 g/l). Plsm ws seprted by centrifugtion t 2,000 x g for 10 min t 4 C nd immeditely frozen nd stored t 70 C until rdioimmunossy (RIA). Assy procedure. The plsm ADM concentrtions were mesured with specific RIA following the extrction of plsm, s described previously (14). Briefly, 2 ml plsm ws loded onto Sep Pk C18 crtridge (Wters Corp., Milford, MA, USA) equilibrted with 5 ml sline. Following the wshing of the crtridge with 5 ml sline nd 10% cetonitrile in 0.1% trifluorocetic cid (TFA), the bsorbed peptides were eluted with 4 ml 50% cetonitrile in 0.1% TFA, lyophilized, nd then stored t 70 C until RIA. The plsm extrct ws dissolved in 250 µl RIA buffer (Phoenix Phrmceuticls, Inc., Mountin View, CA, USA) nd 50 mmol/l sodium phosphte buffer (ph 7.4) contining 0.5% bovine serum lbumin, 0.5% Triton X 100, 80 mmol/1 sodium chloride, 25 mmol/l EDTA, 0.05% sodium zide nd 500 KIU/ml protinin. A totl of 100 µl dissolved plsm extrct ws used for n hadm specific RIA, s reported previously (14). The rbbit polyclonl nti hadm ntibody (1:20,000; ct. no. RK ; Phoenix Phrmceuticls, Inc.) used in this RIA did not show ny cross rectivity with hadm (13 52), rt ADM (1 50), humn clcitonin gene relted peptide (CGRP), endothelin 1, α humn ANP (1 28), BNP 32 or C type ntriuretic peptide 22. The interssy coefficient of vrition ws 8%, nd the intr ssy coefficient of vrition ws 6%. The concentrtion of ADM ws expressed in ng/l. The plsm ANP concentrtion ws determined by similr specific immunordiometric ssy for humn ANP (ShionoRIA ANP kit; Shionogi & Co., Ltd., Osk, Jpn). The plsm BNP concentrtion ws mesured by similr method developed by the sme compny (ShionoRIA BNP kit; Shionogi & Co., Ltd.). The ccurcies nd the detiled methods of these ssys hve been described previously (15). Sttisticl nlysis. All continuous dt re expressed s the men ± stndrd devition. Sttisticl nlysis ws performed through liner regression nlysis, which ws further confirmed by Kendll's method or n nlysis of vrince test for multiple comprisons, which ws further exmined using the Student Newmn Keuls's method. Comprisons between two vribles were conducted using n unpired t test, nd comprisons between the pired vlues were nlyzed with pired t test. Ctegoricl vribles were ssessed using the χ 2 or Fisher's exct test. Non normlly distributed dt were nlyzed through the Mnn Whitney U test. P<0.05 ws considered to indicte sttisticlly significnt difference. Results Bseline chrcteristics. The clinicl profiles of the control subjects nd hypertensive ptients in ech stge re summrized in Tble I. No significnt differences were found in the ge nd gender distribution mong the four groups. The men rteril pressure (MAP), BUN nd Scr levels of the hypertensive ptients were significntly higher thn those of the control subjects (P<0.05); these increses dditionlly correlted with the severity of the hypertension stge (P<0.05). The GFRs of the hypertensive ptients exhibited the opposite chnges (P<0.05).

3 EXPERIMENTAL AND THERAPEUTIC MEDICINE 9: , Tble I. Chrcteristics of the study subjects. Control, n=35 Stge Ⅰ EH, n=20 Stge Ⅱ EH, n=25 Stge Ⅲ EH, n=19 Age (yers) 43±4 41±6 44±5 45±7 Mle:femle rtio (n:n) 16:19 9:11 11:14 8:11 MAP (mmhg) 90±8 112±5 124±8,b 138±10,b,c BUN (mg/dl) 17±3 19±2 22±3,b 26±6,b,c Scr (mg/dl) 1.0± ± ±0.4,b 1.8±0.5,b,c GFR (ml/min) 95±9 87±9 79±10,b 72±11,b,c P<0.05 compred with control subjects; b P<0.05 compred with stge Ⅰ EH ptients; c P<0.05 compred with stge Ⅱ EH ptients. MAP, men rteril pressure; BUN, blood ure nitrogen; Scr, serum cretinine; GFR, glomerulr filtrtion rte; EH, essentil hypertension. Figure 1. Plsm concentrtions of (A) ADM, (B) ANP nd (C) BNP in the control nd three hypertension groups. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. Figure 2. Assocition between plsm ADM concentrtion nd (A) blood ure nitrogen, (B) serum cretinine nd (C) glomerulr filtrtion rte in the stge Ⅰ hypertension group. ADM, drenomedullin. Pretherpy peptide levels. Fig. 1 shows the plsm concentrtions of ADM, ANP nd BNP in the control nd three hypertension groups. The men concentrtions of ADM, ANP nd BNP in the hypertension groups were significntly higher thn those in the control group (P<0.05); significnt increses were dditionlly found with increses in the hypertension grde (P<0.05). The ssocitions between the plsm ADM concentrtion nd the BUN level, Scr level nd GFR in the stge Ⅰ, Ⅱ nd Ⅲ hypertension groups re summrized in Figs The plsm ADM concentrtion ws correlted with BUN nd stronger correltion with Scr ws found. The strongest correltion ws observed between the plsm ADM concentrtion nd the GFR but this correltion ws negtive. The ssocitions between the plsm ADM concentrtion nd the MAP, ANP nd BNP levels in the stge Ⅰ, Ⅱ nd Ⅲ hypertension groups re summrized in Figs The ADM concentrtion ws not only correlted with MAP but lso with the plsm concentrtions of ANP nd BNP. The plsm concentrtions of ADM, ANP nd BNP in the stge Ⅰ, Ⅱ nd Ⅲ hypertension groups with or without renl dysfunction re summrized in Tbles II IV. The ptients with incresed Scr ( 1.5 mg/dl) or decresed GFR ( 80 ml/min) hd mrkedly higher plsm concentrtions of ADM, ANP nd BNP thn those of the ptients with norml Scr nd GFR. The plsm ADM, ANP nd BNP levels of the ptients with or without renl dysfunction were lso higher thn those of control subjects. Post therpy results. Tble V shows the clinicl prmeters of the three groups of hypertensive ptients initilly nd 4 weeks fter effective ntihypertensive therpy. Following tretment, the MAP of the ptients ws norml, while the BUN nd Scr levels were decresed compred with the pretherpy vlues

4 1904 HU et l: PLASMA CONCENTRATIONS OF ADM AND NATRIURETIC PEPTIDES IN PATIENTS WITH EH Figure 3. Assocition between plsm ADM concentrtion nd (A) blood ure nitrogen, (B) serum cretinine nd (C) glomerulr filtrtion rte in the stge IⅠ hypertension group. ADM, drenomedullin. Figure 4. Assocition between plsm ADM concentrtion nd (A) blood ure nitrogen, (B) serum cretinine nd (C) glomerulr filtrtion rte in the stge IIⅠ hypertension group. ADM, drenomedullin. Figure 5. Assocition between plsm ADM concentrtion nd (A) men rteril pressure, (B) ANP nd (C) BNP in the stge Ⅰ hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. Figure 6. Assocition between plsm ADM concentrtion nd (A) men rteril pressure, (B) ANP nd (C) BNP in the stge ⅠI hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. (P<0.05). By contrst, the GFR ws incresed compred with the pretherpy vlues (P<0.05). The plsm ADM, ANP nd BNP concentrtions in the stge Ⅰ, Ⅱ nd Ⅲ hypertension groups initilly nd 4 weeks fter effective ntihypertensive therpy re summrized in Figs The plsm concentrtions of ADM, ANP nd BNP fell significntly following ntihypertensive tretment (P<0.05). Discussion As 52 mino cid vsodiltory peptide, ADM hs ring structure formed by disulfide bond nd n midted crboxyl terminus nd shows homology with CGRP nd mylin, which re other members of this fmily of peptides (16). It hs been demonstrted tht this peptide is present not only in vriety

5 EXPERIMENTAL AND THERAPEUTIC MEDICINE 9: , Tble II. Plsm concentrtions of ADM, ANP nd BNP in stge Ⅰ hypertensive ptients with or without renl dysfunction. Chrcteristics n ADM (ng/l) ANP (ng/l) BNP (ng/l) Scr 1.5 mg/dl ±2.0,b 31.3±1.9,b 32.4±2.1,b Scr <1.5 mg/dl ±3.8 b 20.5±4.2 b 21.9±3.9 b GFR 80 ml/min ±1.7 b,c 31.8±1.6 b,c 32.9±1.8 b,c GFR >80 ml/min ±4.0 b 21.1±4.6 b 22.4±4.3 b Control subjects ± ± ±2.6 P<0.05 compred with ptients with norml Scr levels; b P<0.05 compred with control subjects; c P<0.05 compred with ptients with norml GFR. Scr, serum cretinine; GFR, glomerulr filtrtion rte; ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. Tble III. Plsm concentrtions of ADM, ANP nd BNP in stge Ⅱ hypertensive ptients with or without renl dysfunction. Chrcteristics n ADM (ng/l) ANP (ng/l) BNP (ng/l) Scr 1.5 mg/dl ±4.4,b 43.8±4.9,b 51.4±5.9,b Scr <1.5 mg/dl ±3.6 b 29.2±3.1 b 35.2±3.5 b GFR 80 ml/min ±3.9 b,c 44.4±4.5 b,c 52.2±5.3 b,c GFR >80 ml/min ±4.0 b 29.8±3.5 b 35.8±3.8 b Control subjects ± ± ±2.6 P<0.05 compred with ptients with norml Scr levels; b P<0.05 compred with control subjects; c P<0.05 compred with ptients with norml GFR. Scr, serum cretinine; GFR, glomerulr filtrtion rte; ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. Tble IV. Plsm concentrtions of ADM, ANP nd BNP in stge Ⅲ hypertensive ptients with or without renl dysfunction. Chrcteristics n ADM (ng/l) ANP (ng/l) BNP (ng/l) Scr 1.5 mg/dl ±4.8,b 62.9±5.9,b 75.3±6.1,b Scr <1.5 mg/dl ±4.2 b 47.7±3.4 b 59.5±4.3 b GFR 80 ml/min ±5.2 b,c 62.1±6.4 b,c 74.5±6.5 b,c GFR >80 ml/min ±3.9 b 46.9±2.9 b 58.5±3.8 b Control subjects ± ± ±2.6 P<0.05 compred with ptients with norml Scr levels; b P<0.05 compred with control subjects; c P<0.05 compred with ptients with norml GFR. Scr, serum cretinine; GFR, glomerulr filtrtion rte; ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. Figure 7. Assocition between plsm ADM concentrtion nd (A) men rteril pressure, (B) ANP nd (C) BNP in the stge ⅠII hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide. of orgns nd cells, but lso in humn plsm (1). Fctors of both the physicl, such s sher nd ventriculr wll stress nd hypoxi, nd humorl, such s cytokines nd endocrine nd prcrine hormones, vriety re known to ffect the synthesis of ADM (16). Compred with control subjects, it hs been found tht the plsm levels of ADM re incresed in ptients

6 1906 HU et l: PLASMA CONCENTRATIONS OF ADM AND NATRIURETIC PEPTIDES IN PATIENTS WITH EH Tble V. Hemodynmic prmeters of the hypertensive subjects. Stge Ⅰ EH, n=20 Stge Ⅱ EH, n=25 Stge Ⅲ EH, n=19 Prmeters At dignosis After drugs At dignosis After drugs At dignosis After drugs MAP (mmhg) 112±5 92±3 124±8 94±4 138±10 95±5 BUN (mg/dl) 19±2 17±2 22±3 19±2 26±6 22±3 Scr (mg/dl) 1.2± ± ± ± ± ±0.3 GFR (ml/min) 87±9 93±7 79±10 88±9 72±11 84±9 P<0.05 compred with subjects t dignosis. MAP, men rteril pressure; BUN, blood ure nitrogen; Scr, serum cretinine; GFR, glomerulr filtrtion rte; EH, essentil hypertension. Figure 8. Plsm (A) ADM, (B) ANP nd (C) BNP concentrtions before nd fter tretment in the stge Ⅰ hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide; EH, essentil hypertension. Figure 9. Plsm (A) ADM, (B) ANP nd (C) BNP concentrtions before nd fter tretment in the stge ⅠI hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide; EH, essentil hypertension. Figure 10. Plsm (A) ADM, (B) ANP nd (C) BNP concentrtions before nd fter tretment in the stge ⅠII hypertension group. ADM, drenomedullin; ANP, tril ntriuretic peptide; BNP, brin ntriuretic peptide; EH, essentil hypertension. with hypertension, hert filure or rteriosclerosis (17,18). Results from genetic mnipultion nd prolonged low dose infusion experiments hve indicted tht ADM cts to suppress increses in blood pressure nd limit the progression

7 EXPERIMENTAL AND THERAPEUTIC MEDICINE 9: , of hypertensive orgn dmge through its protective effects on crdiovsculr tissues (19,20). ANP nd BNP exert similr crdiovsculr effects to ADM, including ntriuresis, diuresis nd vsodilttion (21). In the present study, consistent with previous investigtion by Kohno et l (22), the MAP, BUN nd Scr levels were elevted in ptients with EH nd incresed with the severity of the hypertension stge; by contrst, GFR exhibited the opposite chnges. The elevted MAP cn be simply explined, nd the chnges in the BUN nd Scr levels nd GFR my hve resulted from the renl dmge cused by the hypertension, with more severe chnges occurring with higher disese stge. It hs been demonstrted tht ADM hs brod spectrum of biologicl ctions, including potent vsodilttion, ntriuresis, inhibition of renin nd ldosterone secretion, nd inhibition of vsculr smooth muscle cell prolifertion nd migrtion (23). ANP nd BNP, which re predominntly secreted from the trium nd ventricle in the hert, respectively, function s hormones cting ginst further elevtion in BP in hypertensive ptients through their ntriuretic nd vsodiltory effects (24). In the present study, the plsm concentrtions of ADM, ANP nd BNP incresed with incresing disese severity in the ptients with EH, finding consistent with tht in previous study by Kto et l (5). It ppers, therefore, tht high BP is n importnt fctor involved in the observed elevtion of the three peptides in the plsm; s previously mentioned, the renl dmge ws more serious with higher BP. The metbolism of ADM primrily occurs in the kidney, nd ADM concentrtion ws positively correlted with the BUN nd Scr levels but negtively correlted with the GFR in three groups of hypertensive ptients. It is possible, therefore, tht the reduced renl clernce of peptides ccounted for the elevtions in the levels of these bioctive peptides in ptients with EH. This ws further confirmed by the fct tht the plsm ADM, ANP nd BNP concentrtions of the hypertensive ptients with renl dysfunction were significntly higher thn the vlues of the control subjects nd hypertensive subjects without renl dysfunction. Furthermore, the plsm ADM level ws strongly correlted with the level of ANP nd BNP. It cn be inferred tht ADM, long with ANP nd BNP, my be involved in the mechnisms countercting further elevtion in BP due to their similr physiologicl roles, nd tht this is protective nd compenstory mechnism in the crdiovsculr system. This theory ws supported by the ssocition between ADM nd MAP nd higher plsm ADM, ANP nd BNP levels in hypertensive ptients without renl dysfunction compred with control subjects. In ddition, it ws noted tht the plsm levels of ADM, ANP nd BNP were significntly, but not shrply, decresed due to the improvement in MAP nd renl function following ntihypertensive tretment for 4 weeks; therefore, the delivery of ADM, ANP nd BNP to the tissue either through exogenous dministrtion or the ugmenttion of endogenous production should be considered s potentil therpeutic strtegy for number of disorders, prticulrly hypertension. It ws reported by Kto et l (5), however, tht lthough the plsm ADM level ws significntly decresed following urgent ntihypertensive tretment in mlignnt hypertensive ptients, the vlues of ANP nd BNP were not. In ddition, Kohno et l (22) found tht the plsm ADM nd Scr levels were not significntly chnged following ntihypertensive tretment for 4 weeks. The most likely explntions my be tht i) number of elderly hypertensive ptients, whose renl function my not hve esily improved if impired by hypertension, were included in the study by Kohno et l (22); ii) the durtion of the hypertension ws different; nd iii) the sttisticl nlysis ws different. Numerous studies hve found incresed plsm ADM, ANP nd BNP levels in ptients with EH or secondry hypertension (21,25); however, there re few reports on the concentrtions of these vlues in cses of hypertension tht hs been clssified into stges. The present study indicted tht the correltion between the ADM nd BUN levels becme stronger s the severity of the hypertension incresed. Similr correltions between ADM nd Scr levels nd between the ADM level nd GFR were observed. It cn be inferred tht the ADM level is ssocited with renl function nd tht the lower renl clernce of ADM results from the incresingly serious renl dmge cused by hypertension. With regrd to the physiologicl roles of ADM, ANP nd BNP, the results of the present study suggest tht ADM my be involved, long with ANP nd BNP, in mechnisms countercting further elevtion in BP nd my be useful biomrkers for the dignosis nd tretment of ptients with EH. Furthermore, the plsm concentrtions of ADM, ANP nd BNP re strongly ssocited with renl function. Further studies re necessry to clrify the specific physiologicl significnce of ADM, ANP nd BNP in EH nd to elucidte the exct phrmcokinetics of these peptides in hypertensive ptients with renl functionl dmge. Acknowledgements This study ws supported by grnts from the Ntionl Science Fund Project of Chin (no ) nd the Doctor Reserch Fund Project of Wuhn University of Chin (no ). The uthors would like to thnk the Deprtment of Urology nd Crdiology in Renmin Hospitl of Wuhn University. References 1. Kitmur K, Kngw K, Kwmoto M, et l: Adrenomedullin: A novel hypotensive peptide isolted from humn pheochromocytom. Biochem Biophys Res Commun 192: , Hy DL, Wlker CS nd Poyner DR: Adrenomedullin nd clcitonin gene relted peptide receptors in endocrine relted cncers: Opportunities nd chllenges. Endocr Relt Cncer 18: C1 C14, Beltowski J nd Jmroz A: Adrenomedullin wht do we know 10 yers since its discovery? Pol J Phrmcol 56: 5 27, Eto T: A review of the biologicl properties nd clinicl implictions of drenomedullin nd prodrenomedullin N terminl 20 peptide (PAMP), hypotensive nd vsodilting peptides. Peptides 22: , Kto J, Kitmur K, Mtsui E, et l: Plsm drenomedullin nd ntriuretic peptides in ptients with essentil or mlignnt hypertension. Hypertens Res 22: 61 65, Ishimitsu T, Ono H, Minmi J nd Mtsuok H: Pthophysiologic nd therpeutic implictions of drenomedullin in crdiovsculr disorders. Phrmcol Ther 111: , Li Y, Jing C, Wng X, Zhng Y, Shibhr S nd Tkhshi K: Adrenomedullin is novel dipokine: Adrenomedullin in dipocytes nd dipose tissues. Peptides 28: , 2007.

8 1908 HU et l: PLASMA CONCENTRATIONS OF ADM AND NATRIURETIC PEPTIDES IN PATIENTS WITH EH 8. Linchbury JG, Troughton RW, Lewis LK, Yndle TG, Richrds AM nd Nicholls MG: Hemodynmic, hormonl nd renl effects of short term drenomedullin infusion in helthy volunteers. J Clin Endocrinol Metb 85: , Szokodi I, Kinnunen P nd Ruskoho H: Inotropic effect of drenomedullin in the isolted perfused rt hert. Act Physiol Scnd 156: , Federico C: Ntriuretic Peptide system nd crdiovsculr disese. Hert Views 11: 10 15, Kitmur K nd Eto T: Adrenomedullin physiologicl regultor of the crdiovsculr system or biochemicl curiosity? Curr Opin Nephrol Hypertens 6: 80 87, Herget Rosenthl S, Bökenkmp A nd Hofmnn W: How to estimte GFR serum cretinine, serum cysttin C or equtions? Clin Biochem 40: , Whitworth JA; World Helth Orgniztion, Interntionl Society of Hypertension Writing Group: 2003 World Helth Orgniztion (WHO)/Interntionl Society of Hypertension (ISH) sttement on mngement of hypertension. J Hypertens 21: , Kitmur K, Ichiki Y, Tnk M, et l: Immunorective drenomedullin in humn plsm. FEBS Lett 341: , Wng Y, Zhou Y, Meng L, Lu X, Ou N nd Li X: Inflmmtory meditors in Chinese ptients with congestive hert filure. J Clin Phrmcol 49: , Cheung BM nd Tng F: Adrenomedullin: Exciting new horizons. Recent Pt Endocr Metb Immune Drug Discov 6: 4 17, Suzuki Y, Horio T, Hyshi T, et l: Plsm drenomedullin concentrtion is incresed in ptients with peripherl rteril occlusive disese ssocited with vsculr inflmmtion. Regul Pept 118: , Kto J, Kitmur K nd Eto T: Plsm drenomedullin level nd development of hypertension. J Hum Hypertens 20: , Kto J, Tsurud T, Kit T, Kitmur K nd Eto T: Adrenomedullin: A protective fctor for blood vessels. Arterioscler Thromb Vsc Biol 25: , Tsurud T, Kto J, Htkeym K, et l: Antifibrotic effect of drenomedullin on coronry dventiti in ngiotensin II induced hypertensive rts. Crdiovsc Res 65: , Irzmński R, Pwlicki L, Chrłusz M nd Kowlski J: Concentrtion of ntriuretic peptides in ptients suffering from idiopthic rteril hypertension nd left ventriculr distolic dysfunction confirmed by echocrdiogrphy. Clin Exp Hypertens 34: , Kohno M, Hnehir T, Kno H, et l: Plsm drenomedullin concentrtions in essentil hypertension. Hypertension 27: , Kong DG, Go H, Lu YQ, et l: Anxiety disorders re ssocited with incresed plsm drenomedullin level nd left ventriculr hypertrophy in ptients with hypertension. Clin Exp Hypertens 36: 27 31, Grzyw Celińsk A, Celiński R, Kwśniewsk K, Dyczko M, Prystup A nd Mosiewicz J: The usefulness of ntriuretic peptides mesurements in the dignostics of chosen crdiovsculr diseses. Pol Merkur Lekrski 34: , Hlw B: Plsm drenomedullin concentrtion in ptients with essentil hypertension. Pol Merkur Lekrski 5: , 1998.