Caspase inhibition reduces cardiac myocyte dyshomeostasis and improves cardiac contractile function after major burn injury

2007 ◽  
Vol 103 (1) ◽  
pp. 323-330 ◽  
Author(s):  
Deborah L. Carlson ◽  
David L. Maass ◽  
Jean White ◽  
Patricia Sikes ◽  
Jureta W. Horton
Keyword(s):  
Cardiac Myocyte ◽  
Burn Injury ◽  
Contractile Function ◽  
Total Body Surface Area ◽  
Cysteine Proteases ◽  
Sodium Concentration ◽  
Sprague Dawley ◽  
Cardiac Contractile Function ◽  
Caspase 1 ◽  
Major Burn

In the heart, thermal injury activates a group of intracellular cysteine proteases known as caspases, which have been suggested to contribute to myocyte inflammation and dyshomeostasis. In this study, Sprague-Dawley rats were given either a third-degree burn over 40% total body surface area plus conventional fluid resuscitation or sham burn injury. Experimental groups included 1) sham burn given vehicle, 400 μl DMSO; 2) sham burn given Q-VD-OPh (6 mg/kg), a highly specific and stable caspase inhibitor, 24 and 1 h prior to sham burn; 3) burn given vehicle, DMSO as above; 4) burn given Q-VD-OPh (6 mg/kg) 24 and 1 h prior to burn. Twenty-four hours postburn, hearts were harvested and studied with regard to myocardial intracellular sodium concentration, intracellular pH, ATP, and phosphocreatine (23Na/31P nuclear magnetic resonance); myocardial caspase-1, -3,and -8 expression; myocyte Na+ (fluorescent indicator, sodium-binding benzofurzan isophthalate); myocyte secretion of TNF-α, IL-1β, IL-6, and IL-10; and myocardial performance (Langendorff). Burn injury treated with vehicle alone produced increased myocardial expression of caspase-1, -3, and -8, myocyte Na+ loading, cytokine secretion, and myocardial contractile depression; cellular pH, ATP, and phosphocreatine were stable. Q-VD-OPh treatment in burned rats attenuated myocardial caspase expression, prevented burn-related myocardial Na+ loading, attenuated myocyte cytokine responses, and improved myocardial contraction and relaxation. The present data suggest that signaling through myocardial caspases plays a pivotal role in burn-related myocyte sodium dyshomeostasis and myocyte inflammation, perhaps contributing to burn-related contractile dysfunction.

scholarly journals Burn injury decreases myocardial Na-K-ATPase activity: role of PKC inhibition

2007 ◽  
Vol 293 (4) ◽  
pp. R1684-R1692 ◽  
Author(s):  
Jureta W. Horton ◽  
Jing Tan ◽  
D. Jean White ◽  
David L. Maass
Keyword(s):  
Atpase Activity ◽  
Time Course ◽  
Burn Injury ◽  
Contractile Function ◽  
Myocardial Dysfunction ◽  
Total Body Surface Area ◽  
Ringer Solution ◽  
Sodium Accumulation ◽  
Major Burn ◽  
Myocardial Contractile

Cardiomyocyte sodium accumulation after burn injury precedes the development of myocardial contractile dysfunction. The present study examined the effects of burn injury on Na-K-ATPase activity in adult rat hearts after major burn injury and explored the hypothesis that burn-related changes in myocardial Na-K-ATPase activity are PKC dependent. A third-degree burn injury (or sham burn) was given over 40% total body surface area, and rats received lactated Ringer solution (4 ml·kg−1·% burn−1). Subgroups of rats were killed 2, 4, or 24 h after burn ( n = 6 rats/time period), hearts were homogenized, and Na-K-ATPase activity was determined from ouabain-sensitive phosphate generation from ATP by cardiac sarcolemmal vesicles. Additional groups of rats were studied at several times after burn to determine the time course of myocyte sodium loading and the time course of myocardial dysfunction. Additional groups of sham burn-injured and burn-injured rats were given calphostin, an inhibitor of PKC, and Na-K-ATPase activity, cell Na+, and myocardial function were measured. Burn injury caused a progressive rise in cardiomyocyte Na+, and myocardial Na-K-ATPase activity progressively decreased after burn, while PKC activity progressively rose. Administration of calphostin to inhibit PKC activity prevented both the burn-related decrease in myocardial Na-K-ATPase and the rise in intracellular Na+ and improved postburn myocardial contractile performance. We conclude that burn-related inhibition of Na-K-ATPase likely contributes to the cardiomyocyte accumulation of intracellular Na+. Since intracellular Na+ is one determinant of electrical-mechanical recovery after insults such as burn injury, burn-related inhibition of Na-K-ATPase may be critical in postburn recovery of myocardial contractile function.

scholarly journals Effects of burn injury on myocardial signaling and cytokine secretion: possible role of PKC

2007 ◽  
Vol 292 (2) ◽  
pp. R887-R896 ◽  
Author(s):  
Jing Tan ◽  
David L. Maass ◽  
D. Jean White ◽  
Jureta W. Horton
Keyword(s):  
Burn Injury ◽  
Total Body Surface Area ◽  
Cytokine Secretion ◽  
Sprague Dawley ◽  
Inhibitory Peptide ◽  
Adult Rat ◽  
Pkc Isoforms ◽  
Major Burn

This study examined the effects of major burn injury on the cellular distribution of several PKC isoforms in adult rat hearts and examined the hypothesis that PKC plays a regulatory role in cardiomyocyte cytokine secretion. Burn trauma was given over 40% total body surface area in Sprague-Dawley rats. An in vitro model of burn injury included addition of burn serum, 10% by volume, to primary cardiomyocyte cultures (collagen perfusion). In vivo burn injury produced redistribution of PKCδ, PKCε, and PKCα from the cytosol (soluble) to the membrane (particulate) component of the myocardium. This activation of the PKC isoforms was evident 2 h after burn injury and progressively increased over 24 h postburn. Addition of burn serum to isolated myocytes produced similar PKC isoform redistribution from the soluble to the particulate compartment, promoted myocyte Ca2+ and Na+ loading, and promoted robust myocyte secretion of inflammatory cytokines similar to that reported after in vivo burn injury. Pretreating cardiomyocytes with either calphostin or PKCε inhibitory peptide, a potent inhibitor of PKCε, prevented burn serum-related redistribution of the PKCε isoform and prevented burn serum-related cardiomyocyte secretion of TNF-α, IL-1β, IL-6, and IL-10. These data suggest that the PKCε isoform plays a pivotal role in myocardial inflammatory response to injury, altering cardiac function by modulating cardiomyocyte inflammatory cytokine response to injury.

Gender-related differences in myocardial inflammatory and contractile responses to major burn trauma

2004 ◽  
Vol 286 (1) ◽  
pp. H202-H213 ◽  
Author(s):  
Jureta W. Horton ◽  
D. Jean White ◽  
David L. Maass
Keyword(s):  
Burn Injury ◽  
Inflammatory Responses ◽  
Total Body Surface Area ◽  
Left Ventricular Pressure ◽  
Experimental Models ◽  
Left Ventricular ◽  
Female Rats ◽  
Sprague Dawley ◽  
Burn Trauma ◽  
Major Burn

Gender-related differences in immune responses to hemorrhage and sepsis have been described. However, most trauma studies continue to limit experimental models to males to avoid the variable responses associated with hormonal fluctuation in proestrus/estrus females. In the present study, male and female (either diestrus or proestrus/estrus) Sprague-Dawley rats (250–325 g) were given a third-degree scald burn over 40% total body surface area and fluid resuscitated (4 ml/kg per %burn of lactated Ringer solution); sham burn males and diestrus as well as sham burn proestrus/estrus female rats were included to provide controls. Twenty-four hours postburn, hearts were either perfused to examine mechanical function (Langendorff, n = 8 to 9 hearts/group) or to prepare cardiomyocytes (collagenase digestion, n = 4 to 5 hearts/group). Left ventricular developed pressure and the positive and negative first derivative of left ventricular pressure responses to increases in preload were significantly lower in burned males compared with responses measured in either burned proestrus/estrus or burned diestrus females; burn trauma increased cardiomyocyte secretion of tumor necrosis factor-α, interleukin-1β, and nitric oxide to a lesser extent in proestrus/estrus females than levels secreted by either diestrus females or males. Similarly, myocytes from proestrus/estrus females accumulated significantly less sodium/calcium compared with values measured in males ( P < 0.05). Our data confirm gender-related differences in myocardial function and myocardial inflammatory responses to burn injury.

Cellular basis for burn-mediated cardiac dysfunction in adult rabbits

1996 ◽  
Vol 271 (6) ◽  
pp. H2615-H2621 ◽  
Author(s):  
J. W. Horton
Keyword(s):  
Cardiac Myocyte ◽  
Burn Injury ◽  
Total Body Surface Area ◽  
Ringer Solution ◽  
Polymorphonuclear Neutrophils ◽  
Experimental Conditions ◽  
Cardiac Contractile ◽  
Fetal Bovine ◽  
Total Body ◽  
And Control

We have shown that cutaneous burn injury impairs cardiac contractile performance; however, the mechanisms remain unclear. In this study, New Zealand White rabbits were anesthetized with isoflurane, given a full-thickness scald burn over 30% of total body surface area, and resuscitated with lactated Ringer solution (4 ml.kg-1.%burn-1 for 24 h); rabbits handled in an identical fashion were given a sham burn. Serum obtained from burned and control (sham-burned) rabbits was aliquoted and frozen at -70 degrees C until assay. Polymorphonuclear neutrophils (PMN) were isolated 24 h postburn from both sham and burned rabbits to yield preparations with > 95% PMN with > 95% viability. Cardiac myocytes were isolated by retrograde perfusion of hearts with Ca(2+)-free collagenase-Tyrode buffer, suspended in Krebs-Henseleit buffer containing 10% fetal bovine serum and 1.8 mM Ca2+, and incubated (1 x 10(5) cells/well) in a CO2 incubator under several experimental conditions, including buffer alone, buffer plus 10% burn serum, buffer plus 10% sham serum, or buffer plus either burn or sham PMN (25 x 10(5) cells/well). Myocyte viability (%) and creatine kinase (CK; units.ml-1.10(5) cells-1) were unchanged after incubation with sham plasma or sham PMN. Incubation of sham myocytes with burn plasma caused viability to fall (from 79 +/- 3 to 54 +/- 4%, P < 0.002), whereas CK rose (from 1,639 +/- 115 to 2,803 +/- 132 units.ml-1.10(5) cells-1, P < 0.01). Similarly, incubation of sham myocytes with burn PMN reduced viability (from 83 +/- 2 to 50 +/- 3%, P < 0.01), whereas CK remained unchanged (1,880 +/- 168 units.ml-1.10(5) cells-1). Our data indicate that circulating myocardial depressant factors after burn injury contribute to cardiac myocyte injury.

scholarly journals A paradigm shift in practice—the benefits of early active wound temporisation rather than early skin grafting after burn eschar excision

2020 ◽  
Vol 48 (2) ◽  
pp. 93-100
Author(s):  
John E Greenwood
Keyword(s):  
Skin Graft ◽  
Paradigm Shift ◽  
Burn Injury ◽  
Donor Site ◽  
Total Body Surface Area ◽  
Skin Grafting ◽  
Graft Harvest ◽  
Major Burn ◽  
Early Closure ◽  
Total Body

After major burn injury, once survival is achieved by the immediate excision of all deep burn eschar, we are faced with a patient who is often physiologically well but with very extensive wounds. While very early grafting yields excellent results after the excision of small burns, it is not possible to achieve the same results once the wound size exceeds the available donor site. In patients where 50%–100% of the total body surface area is wound, we rely on serial skin graft harvest, from finite donor site resources, and the massive expansion of those harvested grafts to effect healing. The result is frequently disabling and dysaesthetic. Temporisation of the wounds both passively, with cadaver allograft, and actively, with dermal scaffolds, has been successfully employed to ameliorate some of the problems caused by our inability to definitively close wounds early. Recent advances in technology have demonstrated that superior functional and cosmetic outcomes can be achieved in actively temporised areas even when compared with definitive early closure with skin graft. This has several beneficial implications for both patient and surgeon, affecting the timing of definitive wound closure and creating a paradigm shift in the care of the burned patient.

Estrogen-provided cardiac protection following burn trauma is mediated through a reduction in mitochondria-derived DAMPs

2014 ◽  
Vol 306 (6) ◽  
pp. H882-H894 ◽  
Author(s):  
Xiao Yao ◽  
Jane G. Wigginton ◽  
David L. Maass ◽  
Lisha Ma ◽  
Deborah Carlson ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Structural Integrity ◽  
Troponin I ◽  
Burn Injury ◽  
Total Body Surface Area ◽  
Sterile Inflammation ◽  
Effective Control ◽  
Cardiac Protection ◽  
Sprague Dawley ◽  
17Β Estradiol

Mitochondria-derived danger-associated molecular patterns (DAMPs) play important roles in sterile inflammation after acute injuries. This study was designed to test the hypothesis that 17β-estradiol protects the heart via suppressing myocardial mitochondrial DAMPs after burn injury using an animal model. Sprague-Dawley rats were given a third-degree scald burn comprising 40% total body surface area (TBSA). 17β-Estradiol, 0.5 mg/kg, or control vehicle was administered subcutaneously 15 min following burn. The heart was harvested 24 h postburn. Estradiol showed significant inhibition on the productivity of H2O2 and oxidation of lipid molecules in the mitochondria. Estradiol increased mitochondrial antioxidant defense via enhancing the activities and expression of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Estradiol also protected mitochondrial respiratory function and structural integrity. In parallel, estradiol remarkably decreased burn-induced release of mitochondrial cytochrome c and mitochondrial DNA (mtDNA) into cytoplasm. Further, estradiol inhibited myocardial apoptosis, shown by its suppression on DNA laddering and downregulation of caspase 1 and caspase 3. Estradiol's anti-inflammatory effect was demonstrated by reduction in systemic and cardiac cytokines (TNF-α, IL-1β, and IL-6), decrease in NF-κB activation, and attenuation of the expression of inflammasome component ASC in the heart of burned rats. Estradiol-provided cardiac protection was shown by reduction in myocardial injury marker troponin-I, amendment of heart morphology, and improvement of cardiac contractility after burn injury. Together, these data suggest that postburn administration of 17β-estradiol protects the heart via an effective control over the generation of mitochondrial DAMPs (mtROS, cytochrome c, and mtDNA) that incite cardiac apoptosis and inflammation.

Cardiac effects of burn injury complicated by aspiration pneumonia-induced sepsis

2003 ◽  
Vol 285 (1) ◽  
pp. H47-H58 ◽  
Author(s):  
Jean White ◽  
James Thomas ◽  
David L. Maass ◽  
Jureta W. Horton
Keyword(s):  
Burn Injury ◽  
Contractile Function ◽  
Total Body Surface Area ◽  
Multiple Organ ◽  
Male Rats ◽  
Intratracheal Administration ◽  
Degree Burn ◽  
The Subject ◽  
Total Body ◽  
Factor Α

Early fluid resuscitation, antimicrobials, early excision, and grafting have improved survival in the early postburn period; however, a significant incidence of pneumonia-related sepsis occurs after burn injury, often progressing to multiple organ failure. Recent studies have suggested that this initial injury (burn injury) primes the subject, producing an exaggerated response to a second insult, such as pneumonia-related sepsis. We developed an experimental animal model that included a third-degree burn over 40% of the total body surface area, followed by sepsis (intratracheal administration of Streptococcus pneumoniae, 4 × 106 colony-forming unit), which was produced either 48 or 72 h after burn injury in adult male rats. Hearts harvested after either burn alone, sepsis alone, or burn plus sepsis were used to assess either contractile function (Langendorff) or cardiomyocyte secretion of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 (ELISA). Experimental groups included the following: 1) sham (sham burn and no sepsis); 2) burn injury alone studied either 24, 48, or 72 h postburn; 3) pneumonia-related sepsis in the absence of burn injury; and 4) pneumonia-induced sepsis studied either 48 or 72 h after an initial burn injury. Burn injury alone (24 h) or sepsis alone produced myocardial contractile defects and increases in pro- and anti-inflammatory cytokine secretion by cardiomyocytes. Sepsis that occurred 48 h postburn exacerbated the cardiac contractile defects seen with either burn alone or sepsis alone. Sepsis that occurred 72 h postburn produced contractile defects resembling those seen in either burn alone or sepsis alone. In conclusion, our data suggest that burn injury primes the subject such that a second insult early in the postburn period produces significantly greater cardiac abnormalities than those seen with either burn alone or sepsis alone.

scholarly journals P1: CHOLINERGIC RECEPTOR FUNCTION IN CARDIAC ISCHEMIC PRECONDITIONING

2016 ◽  
Vol 64 (3) ◽  
pp. 817.2-817
Author(s):  
CW Mullan ◽  
SA Mavropolous ◽  
K Ojamaa
Keyword(s):  
Ischemic Preconditioning ◽  
Diastolic Pressure ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Structural Complexity ◽  
Cholinergic Receptor ◽  
Left Ventricular ◽  
Sprague Dawley ◽  
Inner Mitochondrial Membrane ◽  
Cardiac Contractile Function

Purpose of StudyCardiac acetylcholine (ACh) signaling is protective, but the role of ACh in ischemic preconditioning (IPC) remains largely unknown. We studied the effect of selective alpha-7 nicotinic ACh receptor (a7nAChR) antagonism by methyllycaconitine (MLA) on the functional benefits of IPC and the effects of this on mitochondrial complexity and inner mitochondrial membrane potential (ψM).Methods UsedMale Sprague Dawley rats (n=17, 322±17 g) were heparinized and anesthetized with 80 mg/kg pentobarbital IP, and their hearts excised and perfused at constant pressure with a non-circulating Langendorff apparatus. Left ventricular (LV) pressure (LVDP) and heart rate (HR) were continually measured with a fluid filled latex balloon attached to a pressure transducer. Treatment groups were: ischemia-reperfusion (IR)(n=6): 20 min. perfusion, 30 min. of global ischemia, 45 min. of reperfusion; IPC (n=5): 10 min. perfusion, 3 min. ischemia with 2 min. reperfusion repeated 3 times prior to IR protocol, IPC+MLA (n=6): 6 min. perfusion, 4 min. of infusion of MLA at 233 nM, IPC with MLA during reperfusion periods, then IR. Mitochondria were isolated from the LV free wall, stained for ψM and for size, and examined by Flow Cytometry with a BD LSRFortessa. Controls (C) (n=4) were freshly excised hearts from similar animals with identical anesthesia.Summary of ResultsIPC increased LV work product (LVDP times HR) as a percent of pre-ischemia (%P) during reperfusion compared to IR control, and this effect was attenuated by MLA pretreatment (IR=24.1±4.5%P, IPC=49.8±2.8%P, IPC+MLA=33.8±3.5%P, p<0.01). IPC reduced end diastolic pressure from IR levels, and this was partially prevented by MLA treatment (IR=78.8±7.7 mm Hg, IPC=18.8±6.6 mm Hg, IPC+MLA=46.3±8.6 mm Hg, p<0.05). IPC maintained mitochondrial structural complexity compared to IR (C=65±6% of total mitochondria, IPC=61±5%, IR=32±4%, p<0.01). MLA reduced the effect of IPC on ψM in intact mitochondria to IR levels (IR=67±10% of intact population, IPC=88±3%, IPC+MLA=71±4%, p<0.01).ConclusionsSignaling through the a7nAChR is necessary for the effect of IPC on maintaining ψM and cardiac contractile function after IR injury.

scholarly journals Urinary Cortisol and Catecholamine Excretion after Burn Injury in Children

2008 ◽  
Vol 93 (4) ◽  
pp. 1270-1275 ◽  
Author(s):  
William B. Norbury ◽  
David N. Herndon ◽  
Ludwik K. Branski ◽  
David L. Chinkes ◽  
Marc G. Jeschke
Keyword(s):  
Burn Injury ◽  
Prospective Trial ◽  
Total Body Surface Area ◽  
Severe Infection ◽  
Reference Ranges ◽  
Infection Rates ◽  
Urinary Cortisol ◽  
Urinary Catecholamines ◽  
Major Burn ◽  
Urine Cortisol

Abstract Introduction: A severe burn causes increased levels of urine cortisol and catecholamines. However, little is known about the magnitude of this increase or how and when the levels return to normal. The purpose of this study was to determine in a large clinical prospective trial the acute and long-term pattern of urine cortisol and catecholamine expression in severely burned children. Methods: Pediatric patients with burns greater than 40% total body surface area (TBSA), admitted to our unit over a 6-yr period, were included into the study. Clinical data including length of stay, number of operations, and duration and number of infections were determined. Patients had regular 24-h urine collections during their acute admission and reconstructive periods. Urine collections were analyzed for cortisol, epinephrine, and norepinephrine. Each urine cortisol was compared with age-adjusted reference ranges. Ninety-five percent confidence intervals and ANOVA analysis were used where appropriate. Results: Two hundred twelve patients were included in the study (75 females and 137 males), with a mean ± sem TBSA of 58 ± 1% (third-degree 45 ± 2%) and mean age of 9 ± 0.4 yr. Urinary cortisol levels were significantly increased (3- to 5-fold) up to 100 d after the burn and then approached normal levels (P &lt; 0.05). The rise in urine cortisol was significantly higher in male than female patients (P &lt; 0.05). Early hypercortisolemia was associated with increased duration of severe infection (P &lt; 0.05). Persistent hypercortisolemia was associated with increases in both infection rates and duration of severe infection (P &lt; 0.05). Urinary catecholamines showed a significant increase at 11–20 d after the burn (P &lt; 0.05). Urinary norepinephrine levels were significantly increased up to 20 d and then returned to normal (P &lt; 0.05). Conclusions: Urinary levels of cortisol, epinephrine, and norepinephrine are significantly increased after a major burn. Early hypercortisolemia is associated with increased duration of severe infection. Persistent hypercortisolemia is associated with increases in both infection rates and duration of severe infection.

IRAK contributes to burn-triggered myocardial contractile dysfunction

2002 ◽  
Vol 283 (2) ◽  
pp. H829-H836 ◽  
Author(s):  
James A. Thomas ◽  
May F. Tsen ◽  
D. Jean White ◽  
Jureta W. Horton
Keyword(s):  
Intracellular Signaling ◽  
Burn Injury ◽  
Contractile Function ◽  
Interleukin 1 ◽  
Large Body ◽  
Cardiac Response ◽  
Contractile Dysfunction ◽  
Intracellular Signaling Pathway ◽  
Major Burn ◽  
Myocardial Contractile

Major burn injury causes myocardial contractile dysfunction, but the molecular basis of this physiological response is incompletely understood. Previous studies demonstrated a role for the interleukin-1 receptor-associated kinase (IRAK) in the cardiac response to acute lipopolysaccharide administration as well as congestive heart failure. In this study, we examined the contribution of IRAK to burn-mediated cardiac responses. After burn injury, hearts from wild-type and IRAK-deficient mice were compared for intracellular signaling pathway activation and contractile function. IRAK-deficient hearts showed impaired activation of kinases that function downstream of IRAK and were partially protected against burn-induced contractile dysfunction. The findings demonstrate that IRAK and the Toll/interleukin-1 pathways participate in the response to large body surface area burns that leads to impaired cardiac contractility.

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