DOI: 10.1016/j.athoracsur.2005.05.070 2005;80:2235-2241 Ann Thorac Surg

and Daniel R. Meldrum Meijing Wang, Ben M. Tsai, Mark W. Turrentine, Yousuf Mahomed, John W. Brown

Functional Depression in the Heartp38 Mitogen Activated Protein Kinase Mediates Both Death Signaling and

http://ats.ctsnetjournals.org/cgi/content/full/80/6/2235located on the World Wide Web at:

The online version of this article, along with updated information and services, is

Print ISSN: 0003-4975; eISSN: 1552-6259. Southern Thoracic Surgical Association. Copyright © 2005 by The Society of Thoracic Surgeons.

is the official journal of The Society of Thoracic Surgeons and theThe Annals of Thoracic Surgery

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he Hearteijing Wang, MD, Ben M. Tsai, MD, Mark W. Turrentine, MD,

ousuf Mahomed, MD, John W. Brown, MD, and Daniel R. Meldrum, MDection of Cardiothoracic Surgery, Departments of Surgery, Cellular and Integrative Physiology and the Indiana Center for

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Background. Understanding the myocardial inflamma-ory response to ischemia is an important part of achiev-ng the elusive clinical goal of long-enduring myocardialrotection. p38 mitogen-activated protein kinase (MAPK)as been implicated in oxidant stress-induced myocar-ial tumor necrosis factor production. However, it isnknown whether p38 MAPK mediates the following

mportant events in both myocardial apoptosis and func-ional depression: mitogen-activated protein kinase-acti-ated protein kinase 2, caspase-1, caspase-3, andaspase-11 activation, and tumor necrosis factor, interleu-in-1� and interleukin-6 production.Methods. Isolated rat hearts were perfused and sub-

ected to an ischemia-reperfusion insult, with and with-ut preischemic infusion of 20�M SB203580 (p38 MAPKnhibitor). Myocardial functional measurements wereontinuously recorded throughout the experiments.

yocardial tissue was then assessed for products of p38APK activation, expression of tumor necrosis factor,

nterleukin-1� and interleukin-6, and activation ofaspase-1, caspase-3 and caspase-11.

Results. Postischemic recovery of left ventricular de-

eloped pressure, �dP/dt and �dP/dt was significantly

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ddress correspondence to Dr Meldrum, 545 Barnhill Dr, Emerson Hall15, Indianapolis, IN 46202; e-mail: dmeldrum@iupui.edu.

2005 by The Society of Thoracic Surgeonsublished by Elsevier Inc

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ncreased by p38 MAPK inhibition (MKI) (left ventricu-ar developed pressure: 48.4 � 3.87 MKI versus 32.7 �.32 mm Hg; �dP/dt: 1392.0 � 141.7 MKI versus 896.7 �28.5 mm Hg/s; �dP/dt: �889.9 � 97.63 MKI versus548.9 � 71.29 mmHg/s). p38 MAPK inhibition also

ignificantly reduced ischemia–reperfusion-induced ele-ation of left ventricular end-diastolic pressure (82.76 �.59 MKI vs 69.95 � 3.55 mm Hg). p38 MKI decreasedyocardial tumor necrosis factor, interleukin-1� and

nterleukin-6 protein levels, and reduced active myocar-ial caspase-1, caspase-3 and caspase-11.Conclusions. The p38 MAPK pathway indeed mediates

he following important events in myocardial apoptosisnd functional depression: mitogen-activated protein ki-ase-activated protein kinase 2, caspase-1, caspase-3 andaspase-11 activation, and tumor necrosis factor, interleu-in-1�, interleukin-6 production after myocardial isch-mia. Single site (p38 MAPK) inhibition of these eventsay have important therapeutic implications in myocar-

ial protection.

(Ann Thorac Surg 2005;80:2235–41)

© 2005 by The Society of Thoracic Surgeons

cute injury in the form of ischemia, endotoxemia, orburn trauma results in myocardial functional sup-

ression, in part by the local production of inflammatoryediators such as tumor necrosis factor (TNF)-�, inter-

eukin-1� (IL-1�) and interleukin-6 (IL-6) [1–3]. Theseediators may be important contributors to postischemicyocardial dysfunction, apoptosis, and hypertrophy.ne of the key signaling enzymes involved in myocardialroinflammatory cytokine production and apoptosis is38 mitogen-activated protein kinase (MAPK) (Fig 1) [4,]. Activation of myocardial p38 MAPK after ischemia-eperfusion (I-R) has been observed in animal and hu-an studies [6–8], and inhibition of p38 MAPK activation

esults in improved myocardial function after I-R injury9–12]. Although abundant evidence exists regarding themportant role of p38 MAPK in signal transduction lead-

ccepted for publication May 19, 2005.

ng to myocardial apoptosis after I-R injury, little isnown about the influence of p38 MAPK on the following

mportant events in myocardial apoptosis and functionalepression: mitogen-activated protein kinase-activatedrotein kinase 2 (MAPKAPK2), caspase-1, caspase-3, andaspase-11 activation, and TNF, IL-1�, and IL-6 produc-ion after myocardial ischemia. The potential therapeuticpportunity to provide single site (eg, p38 MAPK) inhi-ition of these events may have clinical appeal.

aterial and Methods

nimalsdult (280 to 300 g) male Sprague-Dawley rats (Harlan,

ndianapolis, IN) were fed a standard diet and acclimatedn a quiet quarantine room for 2 weeks before thexperiments. The animal protocol was reviewed andpproved by the Indiana Animal Care and Use Commit-

ee of Indiana University. All animals received humane

0003-4975/05/$30.00doi:10.1016/j.athoracsur.2005.05.070

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are in compliance with the “Guide for the Care and Usef Laboratory Animals” (National Institutes of Health,ublication No. 85-23, revised 1985).

solated Heart Preparation (Langendorff)ats were anesthetized (sodium pentobarbital, 60 mg/kg

ntraperitoneally) and heparinized (500 units intraperito-eally), and hearts were rapidly excised through a me-ian sternotomy and were placed in 4°C Krebs-Henseleitolution. The aorta was cannulated and the heart waserfused (70 mm Hg) with oxygenated (95% O2 5% CO2)rebs-Henseleit solution (37°C). Composition of Krebs-enseleit solution was (in mM): 5.5 glucose, 119 NaCl, 1.2aCl2, 4.7 KCl, 25 NaHCO3, 1.18 KHPO4, and 1.17 MgSO4

Sigma, St. Louis, MO). The perfusion buffer was contin-

ig 1. The p38 mitogen-activated protein kinase (MAPK) signalingn inflammation and apoptosis. Acute ischemia-reperfusion, oxidanttress, and hydrogen peroxide directly activate p38 MAPK, whichesults in activation of downstream signal-mitogen-activated proteininase-activated protein kinase 2 (MAPKAPK2). Active p38 MPAKnd MAPKAPK2 lead to tumor necrosis factor (TNF) gene induction.uclear factor kappa B (NF�B) is activated by inhibitory �B (I�B)hosphorylation and subsequently disruption of the NF�B-I�B com-lex. Activated NF�B translocates from the cytoplasm to the nucleus,here it docks to the TNF promoter and activates TNF gene tran-

cription. Active p38 MAPK and MAPKAPK2 also result in produc-ion of interleukin-1 beta (IL-1�) by active/cleaved caspase-11 andaspase-1. The inflammatory response (p38 MAPK signaling, TNF,nd IL-1�) and caspase-11 eventually lead to active caspase-3 andpoptosis.

ously filtered through a 0.45 microfilter to remove i

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articular contaminants. Analysis of the gassed perfusateevealed pO2 of 440 to 460 mm Hg, pCO2 of 39 to 41 mmg, and pH of 7.39 to 7.41 (ABL-4 blood gas analyzer,adiometer, Copenhagen, Denmark). A pulmonary arte-

iotomy and left atrial resection were performed prior tonsertion of a water-filled latex balloon through the lefttrium into the left ventricle. The pre-load volume (bal-oon volume) was held constant during the entire exper-ment to allow continuous recording of the left ventricu-ar developed pressure and left ventricular end-diastolicressure (LVEDP). The balloon was adjusted to a meanVEDP of 5 mm Hg (range, 4 to 8 mm Hg) during the

nitial equilibration. Pacing wires were fixed to the righttrium, and hearts were paced at approximately 6 Hz, 3, 2 ms (350 beats per minute) throughout perfusion. A

hree-way stopcock above the aortic root was used toreate global ischemia, during which the heart waslaced in a 37°C degassed organ bath. Data was contin-ously recorded using a PowerLab 8 preamplifier/igitizer (AD Instruments Inc, Milford, MA) and anpple G4 Power PC computer (Apple Computer Inc,upertino, CA). The maximal positive and negative val-es of the first derivative of pressure (�dP/dt anddP/dt) were calculated using PowerLab software.

xperimental Groupsach I-R experiment lasted a total of 80 minutes: 15inute equilibration period, 25 minutes of global isch-

mia (37°C), and 40 minutes of reperfusion. The I-R waserformed in the presence (I-R � p38 MKI; n � 19) orbsence (I-R alone; n � 14) of the p38 MAPK inhibitor SB03580 (Sigma, St. Louis, MO). SB 203580 (final concen-ration 20 �M) was prepared daily in Krebs-Henseleitolution and infused through a port above the aortic rootnot re-circulated) during the last 5 minutes of the equil-bration period and prior to the I-R insult. Control heartsn � 6) underwent 80 minutes of oxygenated perfusionithout any periods of ischemia to ensure preparation

tability. At the conclusion of experiments, hearts wereemoved, sectioned, and snap frozen in liquid nitrogen.

yocardial TNF, IL-1�, and IL-6eart tissue was homogenized in cold buffer containing

0 mM Tris (pH 7.5), 150 mM NaCl, 1 mM EDTA, 1 mMGTA, 1% Triton X-100, 2.5 mM sodium pyrophosphate,mM �-glycerophosphate, 1 mM Na3VO4, 1 �g/mL

eupeptin, and 1 mM PMSF, and were centrifuged at2,000 rpm for 5 minutes. Myocardial TNF, IL-1� (active/leaved) and IL-6 in the cardiac tissue were determinedy enzyme-linked immunosorbent assay using a com-ercially available enzyme-linked immunosorbent assay

et (R&D Systems Inc, Minneapolis, MN and BD Bio-ciences, San Diego, CA). Enzyme-linked immunosor-ent assay was performed according to the manufactur-r’s instructions.

estern Blotting for p38 MAPK and Apoptosisroteinsomogenized heart tissue was subjected to Western

mmunoblot for measurement of p38 MAPK and cleav-

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ge/active caspase-1, caspase-3, and caspase-11. The pro-ein extracts (30 �g/lane) were subjected to electrophore-is on a 12% tris-HCl gel (Bio-Rad, Hercules, CA) andransferred to a nitrocellulose membrane, which wastained by Naphthol blue-black (Bio-Rad) to confirmqual protein loading. The membranes were incubated in% dry milk for 1 hour and then incubated with theollowing primary antibodies: p38 MAP kinase antibody,hosphor-p38 MAP kinase (Thr180/Tyr182) antibody,hosphor-MAPKAPK2 (Thr334) antibody (Cell Signalingechnology, Beverly, MA), caspase-1 p20 (G-19),aspase-3 (H-277), and caspase-11 (M-20) (Santa Cruziotechnology, Santa Cruz, CA), and were followed by

ncubation with horseradish peroxidase-conjugated goatnti-rabbit and bovine anti-goat IgG secondary antibodynd detection using supersignal west pico stable perox-de solution (Pierce, Rockford, IL). Films were scannedsing an Epson Perfection 3200 Scanner (Epson America,ong Beach, CA) and band density was analyzed usingotalLab Software (Fotodyne, Hartland, WI).

resentation of Data and Statistical Analysisll reported values are mean � standard error of theean. Data were compared using two-way analysis of

ariance (ANOVA) with post-hoc Bonferroni/Dunn testnd unpaired t tests. Differences at the 95% confidenceevel were considered statistically significant.

esults

yocardial Function-R resulted in a marked decrease (p 0.001) in myocar-ial function, as demonstrated by a decrease in left

entricular developed pressure (mm Hg) from 103.8 � W

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.73 to 32.7 � 4.32 and 100.5 � 2.20 to 48.4 � 3.87 in I-Rlone (n � 14) and I-R � p38 MKI (n � 19) groups,espectively (Fig 2A). Postischemic recovery of left ven-ricular developed pressure at 30 and 40 minutes ofeperfusion in the I-R � p38 MKI group was significantlyigher than that in I-R alone group (I-R � p38 MKI: 43.85

3.92 vs I-R alone: 30.31 � 3.42 at 30 minutes [p 0.01];-R � p38 MKI: 49.50 � 3.87 vs I-R alone: 32.68 � 4.32 at0 minutes [p 0.001]).The LVEDP increased in response to ischemia and

eperfusion (Fig 2B). However, the p38 MKI group dem-nstrated lower LVEDP at each time point during reper-usion compared with I-R alone. At 20 minutes of reper-usion, the I-R � p38 MKI group (69.95 � 3.55) had lowerVEDP (mm Hg) compared with the I-R alone group

82.76 � 4.59); (p 0.05). This trend continued at 30inutes (I-R � p38 MKI: 60.51� 4.37 vs I-R alone: 77.98 �

.96; p 0.001) and 40 minutes (I-R � p38 MKI: 59.99 �

.72 vs I-R alone: 75.44 � 5.16; p 0.01) of reperfusion.here was no difference in left ventricular systolic pres-ure before (I-R alone: 108.8 � 3.30; I-R � p38 MKI: 105.9

2.20 mm Hg) or after I-R (I-R alone: 111 � 2.19; I-R �38 MKI: 111.5 � 2.55 mm Hg).The �dP/dt and �dP/dt were impaired at the start of

eperfusion (Figs 2C, 2D), but toward the end of theeperfusion period (40 min), the I-R � p38 MKI groupad greater improvement in �dP/dt (1,433 � 144.4 vs I-Rlone: 896.7 � 128.5; p 0.01) and �dP/dt (�920.6 � 98.7s I-R alone: �549.0 � 71.3; p 0.01) compared with the-R alone group.

38 MAPK Activationctivation of p38 MAPK pathway was determined by

Fig 2. Changes in myocardialfunction after ischemia and reper-fusion in ischemia/reperfusion(I/R) alone (n � 14) and I/R �p38 mitogen-activated protein ki-nase inhibitor (MKI) (n � 19) rathearts perfused with modifiedKrebs-Henseleit solution. (A) Leftventricular (LV) developed pres-sure. (B) Left ventricular end-diastolic pressure. (C) The �dP/dt.(D) The �dP/dt. Results are mean� standard error of the mean. *p 0.05. **p 0.01. ***p 0.001 ver-sus I/R alone at the correspondingpoints.

estern blot assessment of phosphorylated p38 MAPK

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nd its downstream substrate, mitogen-activated proteininase-activated protein kinase 2 (MAPKAPK2). Acute

schemia and reperfusion resulted in increased activationf p38 MAPK (phosphorylated-p38 MAPK demonstrateds percentage of total p38) (I-R alone, [n � 6]: 81.5 � 5.2%s control [n � 5]: 36.0 � 10.3%; p 0.05) and MAP-APK2. Figure 3A shows equal total p38 MAPK in allroups, but increased phosphorylation of p38 MAPK andAPKAPK2 in the I-R alone hearts (81.5 � 5.2%; n � 6),hich were decreased by p38 MAPK inhibition (54.7 �

4.8%; n � 4). Equal loading of the samples was con-rmed by Naphthol blue-black staining.

38 MAPK Inhibition Decreased Cardiacnflammatory Response to Ischemia-Reperfusiono determine the effect of p38 MAPK inhibition by SB03580 on the inflammatory response to I-R, myocardialNF, IL-1�, and IL-6 protein levels (expressed in pg/mg

otal protein) were measured by enzyme-linked immu-osorbent assay. The p38 MAPK inhibition reduced I-R-

nduced production of TNF (I-R � p38 MKI: 138.5 � 13.8s I-R alone: 188.2 � 19.2; p 0.05), IL-1� (I-R � p38 MKI:89.5 � 14.6 vs I-R alone: 236.8 � 11.2; p 0.05), and IL-6

ig 3. The expression of activated38 mitogen-activated protein ki-ase (MAPK) signaling pathway

s increased after ischemia/reperfu-ion (I/R) injury in I/R alone rela-ive to I/R � p38 mitogen-activatedrotein kinase inhibitor (MKI). (A)epresentative immunoblots showonphosphorylated p38 MAPKtotal) in the top row with phos-horylated p38 MAPK (active) inhe bottom row. (B) Representativemmunoblots show phosphorylateditogen-activated protein kinase-

ctivated protein kinase 2 (MAP-APK2) (active). (C) Densitometryata of p-p38 MAPK (percentagef total p38 MAPK). (Mean �tandard error of the mean [n � 4o 6/group].) *p 0.001 versusontrol, �p 0.05 versus I/Rlone.

ig 4. Ischemia-reperfusion (I/R)-induced production of (A) myocardnterleukin-6 (IL-6) protein. Protein levels of myocardial TNF, IL-1�,rotein kinase inhibitor decreased these myocardial cytokines compar

/group]). *p 0.05 versus control; �p 0.05 versus I/R alone.

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I-R � p38 MKI: 436.9 � 22.1 vs I-R alone: 624.9 � 56.6; p0.05) protein (Fig 4).

38 MAPK Inhibition Reduced Myocardial Caspase-1,aspase-3, and Caspase-11 After Ischemia andeperfusionhe cleaved active forms of myocardial caspase-1,aspase-3, and caspase-11 were detected by Westernlot. I-R increased expression of active caspase-1 (I-Rlone: 109.8 � 7.1% [n � 8] vs control: 67.1 � 9.4% [n � 3]; 0.05) and caspase-11 (I-R alone: 126.5 � 7.2% [n � 8]

s control: 86.2 � 18.1% [n � 3]; p 0.05) (Fig 5). The p38APK inhibition resulted in decreased activation of

aspase-1 (75.1 � 12.9% [n � 7]), caspase-3, andaspase-11 (103.7 � 7.2% [n � 9]) in the heart subjected to-R injury (Figs 5, 6).

omment

he results presented here constitute the initial demon-tration that the p38 MAPK pathway indeed mediates theollowing important events in myocardial apoptosis andunctional depression: MAPKAPK2, caspase-1, caspase-3,

mor necrosis factor (TNF), (B) interleukin-1 beta (IL-1�), and (C)IL-6 were significantly increased by I/R, but p38 mitogen-activatedth I/R alone. (Mean � standard error of the mean [n � 4 to

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nd caspase-11 activation, and TNF, IL-1�, and IL-6roduction after myocardial ischemia. Single site (p38APK) inhibition of these events may have important

herapeutic implications in myocardial protection.p38 MAPK is activated by ischemia and reperfusion [7,

0, 11, 13]. In the current study, p38 MAPK inhibitionesulted in a marked decrease in myocardial injury and aignificant increase in myocardial function during reper-usion (Fig 2). To assess the relative contribution ofystolic versus diastolic improvement in the recovery ofeft ventricular developed pressure, we also analyzed leftentricular systolic pressure. Surprisingly, we found thathere was no difference with p38 MAPK inhibition on leftentricular systolic pressure. This suggests that the im-rovement in left ventricular developed pressure pro-uced by p38 MAPK inhibition was due to improvement

n diastolic function (LVEDP). Thus it appears that p38APK inhibition acts predominantly by decreasing the

stiffness” of the heart. However, we observed an ap-roximately equal improvement in �dP/dt and �dP/dt.s dP/dt is dependent on loading conditions and theVEDP between the two groups is different, we believe

hat this might have led to the differences in �dP/dt,lthough the contractility and systolic function might beimilar.

The p38 MAPK inhibition resulted in a slight decreasef LVEDP during the 25-minute period of ischemiaompared with I-R alone. However, a marked decrease of

ig 5. Expression of caspase-1 and caspase-11 in control, ischemia-rehown are representative immunoblots of precursor procaspase-11 inepresentative immunoblots of precursor procaspase-1 in the top rowaspase-11 (% of procaspase-11). The I/R increased expression of actieduced by p38 mitogen-activated protein kinase inhibition (MKI). (Devels were increased after I/R. However, increased caspase-1 activatiorror of the mean [n � 3 to 9/group]). *p 0.05 versus control. �p

VEDP was observed after 20 minutes of reperfusion

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ith p38 MAPK inhibition. This observation is consistentith studies in which ischemia alone resulted in a mod-

rate increase in p38 MAPK activation, whereas signifi-antly greater activation of p38 MAPK was observed withhe addition of reperfusion [10, 14]. It is evident thatctivation of p38 MAPK is an important signaling step inhe development of myocardial injury, and this process

ay be related to its role in promoting proinflammatoryytokine production.

The I-R injury induces the local production of TNF,L-1�, and IL-6 [15–17]. It is now known that cardiomyo-yte production of proinflammatory cytokines is partlyesponsible for myocardial dysfunction after acute injury3, 18, 19]. Recently p38 MAPK activation has beenorrelated with proinflammatory cytokine production inyocardium after endotoxemia and burn trauma [8, 20].owever, whether activation of p38 MAPK plays an

mportant role in postischemic myocardial inflammatoryytokine production is less clear. In this regard, p38

APK inhibition resulted in decreased postischemicyocardial TNF, IL-1�, and IL-6 production, and their

roduction occurred independent of blood-borne ele-ents. The results presented here indicate that I-R inju-

y-induced myocardial production of TNF, IL-1�, andL-6 is correlated with physiologic dysfunction and in-ury, and p38 MAPK inhibition attenuates both physio-ogic dysfunction-injury and myocardial inflammatoryytokine production.

sion (I/R) alone and I/R � p38 MKI rat hearts after I/R injury. (A)p row with active caspase-11 in the bottom row. (B) Shown are

active caspase-1 in the bottom row. (C) Densitometry data ofspase-11 levels. The increased caspase-11 activation after I/R wasnsitometry data of caspase-1 (% of procaspase-1). Active caspase-1er I/R was reduced by p38 MAPK inhibition. (Mean � standard5 versus I/R alone.

perfuthe towithve ca) Den aft

In this study, we demonstrated that expression of TNF

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as decreased by p38 MAPK inhibitor administrationfter I-R. This finding is consistent with other studieshowing that TNF production after I-R is dependent on38 MAPK activation [4, 5], and regulation of this processay occur at the pre-transcriptional level (Fig 1). Simi-

arly, the effects of p38 MAPK on IL-1� and IL-6 maynvolve signaling steps proximal to the final active formsf these cytokines. Recently, caspase-1 and caspase-11ere shown to function upstream of IL-1� maturation

21]. Interleukin-1� is initially synthesized as an inactiverecursor requiring the IL-1�-converting enzyme oraspase-1 for cleavage to the mature, biologically activeolecule [22, 23]. Interleukin-1�-converting enzyme was

equired for IL-1� activation in the postischemic heart24]. Activation of caspase-1 is dependent on caspase-1125]. Caspase-11 is believed to activate downstream sig-als caspase-1 and caspase-3, and thus it may be impor-

ant in both inflammation and apoptosis. It has beenemonstrated that caspase-11 induced by lipopolysac-haride and hypoxia in microglia was mediated through38 MAPK [26, 27]. Our results indicate that p38 MAPK

nhibition reduces activation of caspase-11, which mayesult in decreased caspase-1 (IL-1�-converting enzyme)nd subsequent inhibition of IL-1� production. Thistudy is the first to correlate myocardial IL-1� productionith caspase-1 and caspase-11 activation through a p38APK-mediated pathway.The role of p38 MAPK in IL-6 production is less clear.

here is evidence that p38 MAPK regulates IL-6 produc-ion in vascular smooth muscle cells by activating the

ig 6. Expression of activeaspase-3 in ischemia-reperfusionI/R) alone and I/R � p38 mitogen-ctivated protein kinase inhibitorMKI) rat hearts. (A) Representativemmunoblots of active caspase-3p20 and p17 subunits). (B) Densi-ometry data of active caspase-3p20 and p17) (% of caspase-3 p20,17 in I/R alone group, respec-ively). (Mean � standard error ofhe mean [n � 3/group].) *p 0.05.*p 0.001 versus I/R alone.

AMP response (CRE) site and cAMP response site

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inding protein (CREB) [28]. However, it is possible thathe reduction in IL-6 is directly related to the SB 203580-nduced decrease in TNF and IL-1�, which stimulatesL-6 production [29, 30]. Indeed, in a previous study, weemonstrated that sequestering TNF with TNF bindingrotein reduced IL-6 to a level similar to that observedfter SB 203580 administration in the heart exposed toipopolysaccharide [20].

Evidence indicates that improved functional recoverynd decreased myocardial injury with p38 MAPK inhibi-ion correlates with decreased proinflammatory cytokineroduction and decreased activation of caspase-1,aspase-3, and caspase-11. Further understanding of theignaling pathways involved in injury-induced myocar-ial inflammation and methods of limiting these delete-ious effects may translate into clinically applicable ther-peutics and single site inhibition of both cytokineroduction and proapoptotic signaling.

his work was supported in part by the National Institutes ofealth grant no. R01GM70628 (DRM).

eferences

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DOI: 10.1016/j.athoracsur.2005.05.070 2005;80:2235-2241 Ann Thorac Surg

and Daniel R. Meldrum Meijing Wang, Ben M. Tsai, Mark W. Turrentine, Yousuf Mahomed, John W. Brown

Functional Depression in the Heartp38 Mitogen Activated Protein Kinase Mediates Both Death Signaling and

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