Spelling suggestions: "subject:"myocardial reperfusion"" "subject:"myocardial eperfusion""
21 |
Myocardial ischemia-reperfusion injury and systemic inflammatory response in high-risk cardiac surgery:a clinical study of the effects of high-dose glucose-insulin treatment and the use of leukocyte-depleting filterKoskenkari, J. (Juha) 03 October 2006 (has links)
Abstract
Cardiac surgery with cardiopulmonary bypass induces the activation of systemic inflammatory response syndrome (SIRS) and results in at least some degree of global myocardial ischemia. Although these responses are usually short-lived, they may lead to serious complications and organ system failures.
The present study evaluated the effects of high-dose glucose-insulin (1IU/kg/h) treatment (GIK) administered with the hyperinsulinemic normoglycemic clamp technique and a leukocyte-depleting filter on markers of systemic inflammatory response and myocardial ischemia-reperfusion injury in certain cardiac surgical risk groups.
The study involved four prospective randomized controlled clinical trials and 119 patients. Cardioprotective effects were measured as myocardial enzyme release, recovery of contractile function and incidence of arrhythmias in all studies. The hemodynamic and metabolic effects of high-dose glucose-insulin treatment were evaluated in patients admitted for combined aortic valve (AS) and coronary surgery (40) and for urgent coronary surgery (39), and the latter study also involved proinflammatory cytokine and C-reactive protein analyses. The impacts of leukocyte filter on the expression of neutrophil adhesion molecules along with proinflammatory cytokines were evaluated in patients admitted for combined aortic valve (AS) and coronary surgery (20) and for solitary coronary surgery (20).
The high-dose glucose-insulin treatment was associated with better preserved myocardial contractile function and less need for inotropic support after combined aortic valve and coronary surgery (I) and attenuation of postoperative CRP release after urgent coronary surgery (II). No effects on postoperative myocardial enzyme release (I, II) or on proinflammatory cytokine responses (II) were detected. The number of hypoglycemic events was low. The use of a leukocyte filter throughout the cardiopulmonary bypass period increased the neutrophil adhesion molecule CD11b expression in patients with both normal and prolonged CPB times and was associated with an enhanced proinflammatory cytokine response (III, IV).
In conclusion, high-dose glucose-insulin treatment is safe, but requires strict control of blood glucose level. It reduces the need for inotropic support in patients with compromised cardiac status. The use of leukocyte filter leads to increased leukocyte activation and proinflammatory reaction.
|
22 |
Myocardial protection during cardiac surgeryVon Oppell, Ulrich O 30 March 2017 (has links)
No description available.
|
23 |
Prevention of Ischemia/Reperfusion-Induced Cardiac Apoptosis and Injury by Melatonin Is Independent of Glutathione Peroxdiase 1Chen, Zhongyi, Chua, Chu C., Gao, Jinping, Chua, Kao W., Ho, Ye S., Hamdy, Ronald C., Chua, Balvin H.L. 01 March 2009 (has links)
Free-radical generation is one of the primary causes of myocardial ischemia/reperfusion (I/R) injury. Melatonin is an efficient free-radical scavenger and induces the expression of antioxidant enzymes. We have previously shown that melatonin can prevent free-radical-induced myocardial injury. To date, the mechanism underlying melatonin's cardioprotective effect is not clear. In this study, we assessed the ability of melatonin to protect against I/R injury in mice deficient in glutathione peroxidase 1 (Gpx1). Mice hearts were subjected to 40 min of global ischemia in vitro followed by 45 min of reperfusion. Myocardial I/R injury (expressed as % of recovery of left ventricular developed pressure × heart rate) was exacerbated in mice deficient in Gpx1 (51 ± 3% for Gpx1+/+ mice versus 31 ± 6% for Gpx1-/- mice, P < 0.05). Administration of melatonin for 30 min protected against I/R injury in both Gpx1+/+ mice (72 ± 4.8%) and Gpx1-/- mice (63 ± 4.7%). This protection was accompanied by a significant improvement in left ventricular end-diastolic pressure and a twofold decrease in lactate dehydrogenase (LDH) level released from melatonin-treated hearts. In another set of experiments, mice were subjected to 50 min of ligation of the left descending anterior coronary artery in vivo followed by 4 hr of reperfusion. The infarct sizes, expressed as the percentage of the area at risk, were significantly larger in Gpx1-/- mice than in Gpx1+/+ mice (75 ± 9% versus 54 ± 6%, P < 0.05) and were reduced significantly in melatonin-treated mice (31 ± 3.7% Gpx1-/- mice and 33 ± 6.0% Gpx1+/+ mice). In hearts subjected to 30 min of coronary artery occlusion followed by 3 hr of reperfusion, melatonin-treated hearts had significantly fewer in situ oligo ligation-positive myocytes and less protein nitration. Our results demonstrate that the cardioprotective function of melatonin is independent of Gpx1.
|
24 |
Effect of adenosine and lidocaine on cardiac functional and metabolic recovery after global ischemia and reperfusionVos, Lynette C. 01 January 1994 (has links)
This study investigated if exogenous adenosine (ADO) improves recovery of cardiac function during repetfusion (RPF) after global ischemia (ISC), and if lidocaine is required for. ADO-mediated cardioprotection during reperfusion. Isolated rabbit hearts, retrogradely perfused with erythrocyte-enriched Krebs-Henseleit buffer at constant left ventricular (LV) volume and physiologic flow rates, were subjected to 20 min. of global no-flow ischemia, and reperfused at the same rate as before ischemia. Hearts received one of the following treatments: 1) control (CON; no drug treatment), 2) adenosine (ADO; 200J.1M before and after ISC), or 3) adenosine+lidocaine (NL; 200 JlM ADO before and after ISC, 1 J.Lg/ml/min LIDO during first 20 min. of RPF). Myocardial function (e.g., using developed LV pressure, DP) declined as expected during no-flow ischemia and gradually returned during reperfusion. Functional recovery in ADO and NL groups were significantly improved from CON during early RPF (p<0.05 at 2 min RPF), but not at later RPF times(> 10 min). Differences did not exist between ADO and NL groups at any RPF time except at 10 min. RPF. Additionally, myocardial ATP content was measured before ischemia, after ischemia, and after 10 and 30 min of reperfusion. ATP content decreased significantly during ischemia; ADO hearts showed a increased repletion (85% of pre-ischemia level) of ATP at 30 min. of reperfusionas compared to CON (60%). These data suggest that ADO alone improves cardiac functional recovery during early repetfusion; LIDO does not appear to be required for ADO-mediated cardioprotection. ADO and LIDO do not improve cardiac function, however, ADO appears to improve myocardial ATP repletion at later RPF times in this blood-perfused rabbit model of global myocardial ISC/RPF.
|
25 |
The role of p38 MAPK activation in preconditioning mediated protection against ischaemia/reperfusion injuryHartley, Shahiem 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The ultimate consequence of the interruption of blood flow to the myocardium is
necrosis. In view of the prevalence of coronary artery disease in the general
population, and the deleterious effects of myocardial ischaemia on myocardial
tissue, it is important to develop new strategies to protect the myocardium against
ischaemia. Necrosis of myocardial tissue has for a long time been considered to be
the main component of the damage incurred by myocardial infarction. Recently the
importance of the contribution of apoptotic cell death in the context of myocardial
ischaemia/reperfusion injury has become apparent.
There is a general agreement that early reperfusion is necessary to salvage
myocardial tissue from cell death. Preconditioning is the phenomenon whereby
brief episodes of ischaemia and reperfusion protect the heart against a subsequent
longer period of ischaemia. This endogenous mechanism is the strongest form of
protection against myocardial infarction that has yet been described. Apart from
ischaemie preconditioning (IPC), protection can also be elicited with pharmacologic
agents, such as activation of the beta-adrenergic receptor with isoproterenol.
Ischaemie preconditioning protects the myocardium against necrosis, arrhythmias
and apoptosis, and increases functional recovery upon reperfusion. Betaadrenergic
receptor stimulated preconditioning (PPC) has been shown to improve
post-ischaemie functional recovery, but it is not known whether it also protects
against myocardial infarction and apoptosis.
The signaling pathways involved in preconditioning have been extensively studied.
A distinction is usually made between factors that act as triggers, or as mediators
of protection. Triggers activate cellular responses before the onset of sustained
ischaemia, and its involvement is demonstrated by showing that inhibitors of the
trigger bracketing the preconditioning protocol can block its protective effect, or that
transient administration with washout before sustained ischaemia can activate a
protective effect. A mediator operates during sustained ischaemia, and its
involvement is demonstrated by showing that infusion of an inhibitor of its action
immediately prior to sustained ischaemia (without washout) can block its protective
effect. Another approach to demonstrate a mediator role is to attempt to activate
signal transduction pathways during sustained ischaemia. As it is not possible to
infuse substances during ischaemia, activators are infused immediately prior to
ischaemia without washout of the agent and subsequently its effect on protection is
observed.
It is clear that the evolutionary conserved stress activated pathways are involved in
preconditioning. There are three pathways i.e., the extracellular receptor activated
pathways (ERK), c-jun terminal activated kinases (JNK) and p38 mitogen-activated
protein kinases (MAPK). The precise role of the p38 MAPK pathway has not been
elucidated. Experimental evidence has suggested a role for the activation of p38
MAPK as a trigger, as well as a mediator of the protective effect of preconditioning.
There is however also strong evidence that the attenuation of p38 MAPK activation
during sustained ischaemia, rather than its activation, is responsible for the protection that is observed. Furthermore, the role of p38 MAPK has only been
investigated in relation to its protection against necrosis, but not apoptosis.
AIMS:
The aim of this study was to:
(I) Establish a model of preconditioning in neonatal cardiomyocyte cell culture.
The reason was that such a model could potentially enable one to rapidly
elucidate the signal transduction pathways in an environment without the
influence of non-cardiac cells.
(II) Investigate whether IPC and ~PC protect against necrosis and apoptosis.
(III) Elucidate the role of the stress-activated kinase, p38 MAPK, in
preconditioning.
METHODS:
1. Neonatal rat cardiomyocyte cell culture model
A viability assay with 3-[4,5- Dimethylthaizol-2-yl]-2,5-diphenyl-tetrazolium bromide
(MTT) was first developed using different concentrations - a concentration of
0.25% was found to be optimal to determine viability. Neonatal cardiomyocyte cell
cultures were subjected to sustained simulated "ischaemia" by using either 5 mM
KCN plus deoxyglucose (DOG) for 5 min or potassium cyanide (KCN) for 45 min.
Some cell cultures were preconditioned with either chemical ischaemia (5 mM KCN
for 5 min) or isoproterenol (10-7 M) for 5 min and 60 min reoxygenation before
being exposed to sustained simulated ischaemia.
2. Isolated adult rat cardiomyocyte model
Isolated cardiac myocytes were exposed to 2 hours of hypoxia, which was induced
by pelletting the cells by centrifugation, and covering them with a thin layer of
mineral oil. Some groups were preconditioned with either hypoxia for 10 min at
37° C or isoproterenol (10-7 M) for 5 min, followed by reoxygenation for 20 minutes.
The trypan blue exclusion method and MTT method developed in the neonatal
cardiomyocytes were used to assess viability.
3. Isolated perfused rat heart model
3.1 Infarct size was determined in a model of regional ischaemia by using
tetrazolium staining and determining the area of necrosis (exclusion of
tetrazolium) as a percentage of area at risk. These hearts were subjected to
35 min global ischaemia and 30 min reperfusion. Some groups were
preconditioned by three cycles of 5 min global ischaemia or addition of
isoproterenol (10-7 M) for 5 min, followed by 5 min reperfusion before the
onset of sustained regional ischaemia.
3.2 p38 MAPK activation and markers of apoptosis: p38 MAPK activation was
determined using antibodies against dual phosphorylated p38 MAPK (i.e.
activated p38 MAPK). Apoptosis was measured by using antibodies against
activated caspase-3, and against a fragment of PARP (PARP cleavage). For
these experiments isolated rat hearts were exposed to global ischaemia for
25 min followed by 30 min reperfusion. Some groups were preconditioned
with three cycles of 5 min global ischaemia. A global ischaemia model was
used in order to have sufficient tissue available for the Western blot
determinations. This necessitated a shorter period of sustained ischaemia,
as the globally ischaemie heart does not recover sufficiently after a longer
period of ischaemia such as is necessary in regional ischaemia
experiments.
3.3 The role of p38 MAPK in ischaemie preconditioning was investigated by
administration of SB 203580 (1IJM),a selective inhibitor of p38 MAPK, either
bracketing the preconditioning (i.e. to determine its role as a trigger) or for
10 min immediately prior to sustained ischaemia (i.e. to determine its role as
a mediator). The second approach was to use anisomycin, an activator of
p38 MAPK, as a trigger (infusion for 10 min followed by wash out) or as a
mediator (10 min immediately prior to sustained ischaemia) in the same
model as used for determination of p38 MAPK activity. The infusion of
anisomycin for 10 min has been shown to elicit activation of p38 MAPK to a
similar extent as has been observed with an ischaemie preconditioning
protocol. The endpoints used were infarct size and markers of apoptosis.
RESULTS:
1. Neonatal rat cardiomyocyte cell culture model
It was not possible to establish a model of preconditioning of neonatal
cardiomyocytes that was consistently successful. It was therefore decided to
abandon the attempts and to use a different cell model.
2. Isolated adult rat cardiomyocyte model
Isolated adult cardiomyocytes were preconditioned successfully, but produced too
little material to perform simultaneous determinations of cell viability and Western
blots (p38 MAPK activation and markers of apoptosis). It was therefore decided to
use the isolated perfused adult rat heart.
3. Isolated perfused adult rat heart model
3.1 Both IPC and PPCprotect against infarction and apoptosis:
Using two models of preconditioning i.e., IPC and PPC, the protective effects of
preconditioning were demonstrated convincingly against infarction (necrosis). IPC
and PPC both caused a significant reduction in infarct size (12.2±1.4 and
15.2±2.6%) versus Non-PC hearts (29.6±2.9%) (p < 0.001). Both forms of
preconditioning also protected against apoptosis, by significantly reducing the
markers of apoptosis, caspase-3 activation and PARP cleavage. The protection
afforded by both forms of preconditioning was accompanied by a marked decrease
in activation of p38 MAPK upon reperfusion. The relationship between p38 MAPK
and the protection that was elicited by preconditioning was then investigated, namely whether p38 MAPK acted as a trigger, or as a mediator of protection. To
investigate the role of p38 MAPK as a mediator or a trigger in preconditioning, use
was made of (i) a specific inhibitor of p38 MAPK activation i.e., SB 203580 and (ii)
a known activator of p38 MAPK i.e., anisomycin.
3.2 p38 MAPK as a trigger of protection:
Administration of SB 203580 during the IPC protocol and washed out before
sustained ischaemia did not abolish the protective effect of ischaemie
preconditioning, and resulted in a small, but significant increase in caspase-3
activation and PARP cleavage. On the other hand, activation of p38 MAPK with
anisomycin for 10 min followed by washout also resulted in a significant reduction
in necrosis (infarct size 14.9±2.2 versus 29.6±2.9% in Non-PC hearts) (p < 0.001)
and both markers of apoptosis. The latter results suggested that p38 MAPK was a
trigger of preconditioning. If this was the case, why didn't SB 203580 abolish the
protection of IPC? The most likely explanation was that multiple protective
mechanisms were activated during a multi-cycle protocol of ischaemic
preconditioning, of which activation of p38 MAPK was only one. Inhibition of p38
MAPK with SB 203580 would therefore not be expected to block the activation of
those mechanisms that were independent of p38 MAPK, but were still capable of
protecting against necrosis or apoptosis. It is very interesting that a small increase
in apoptosis was observed when SB 203580 was used in this situation, as it may
indicate that the protection against apoptosis was more dependent on the
activation of p38 MAPK than the protection against necrosis, as no effect was seen on infarct size. Another explanation could be that infarct size determination was not
sensitive enough to detect such small effects.
3.3 p38 MAPK as a mediator of protection:
Inhibition of p38 MAPK activation with SB 203580 administered 10 min before
sustained ischaemia caused a significant decrease in infarct size compared to
Non-PC hearts (12.6±1.9 vs 29.6±2.9%) (p < 0.001) equivalent to that of hearts
preconditioned with ischaemia. This was accompanied by a similar pattern of
protection against apoptosis, with significantly reduced activation of caspase-3
activation and PARP cleavage.
These results strongly supported a role for the attenuation of p38 MAPK activation
as a mediator of preconditioning against ischaemia/reperfusion-mediated necrosis
and apoptosis. However, the results of the experiments with anisomycin were at
first glance not compatible with such a conclusion. The administration of the
activator of p38 MAPK, anisomycin, for 10 min immediately prior to sustained
ischaemia resulted in significant protection against necrosis (infarct size 16.6±2.4%
vs 29.6±2.9% in Non-PC hearts) (p < 0.01) and reduced caspase-3 activation and
PARP cleavage indicating less apoptosis. The reason for these findings were
probably that this method of administration of anisomycin did in fact not activate
p38 MAPK during sustained ischaemia, but actually served as a trigger to protect
against ischaemia - similarly as if it had been infused with washout of the drug.
Support for this notion was found in the fact that p38 MAPK activation was decreased upon reperfusion. These results suggested that the logistical problem of
not being able to infuse a drug into the myocardium during ischaemia could not be
overcome by immediate prior infusion, and that the administration of anisomycin in
this way had activated downstream effectors of the p38 MAPK signal transduction
pathway. An important contender for such an effector would be heat shock protein
27 (HSP27), which has been shown to play an important role in protection against
apoptosis, and stabilisation of actin, and thus the cytoskeleton. Another possibility
was that anisomycin had activated the JNK stress activated kinases. The
elucidation of a role of this signal transduction pathway would necessitate the use
of anisomycin in the presence of an agent such as curcumin, an inhibitor of JNK.
Final conclusion:
The work in this thesis showed that the stress activated kinase, p38 MAPK, was
involved in the protective effect of ischaemie preconditioning. The results
suggested a role for the activation of p38 MAPK as a trigger of protection, and the
attenuation of p38 MAPK as a mediator of protection, which was observed in the
reduction of both necrosis (infarct size) and apoptosis as determined with caspase-
3 activation and PARP cleavage. / AFRIKAANSE OPSOMMING: Die afsluiting van bloedvloei na die miokardium gee aanleiding tot nekrose. In die
lig van die voorkoms van koronêre bloedvatsiekte onder die algemene populasie,
en die nadelige effekte van miokardiale isgemie op miokardiale weefsel, is dit
belangrik om nuwe strategieë te ontwikkel wat die miokardium teen isgemie
beskerm. Nekrose van miokardiale weefsel word tradisioneel as die belangrikste
komponent van die skade aangerig deur miokardiale infarksie beskou. Die belang
van apoptotiese seldood in die konteks van miokardiale isgemie/herperfusie (I/R)
het onlangs na vore getree.
Dit word algeneem aanvaar dat vroeë vroegtydige herperfusie noodsaaklik is om
miokardiale weefsel te beskerm teen seldood. Prekondisionering is 'n verskynsel
waartydens kort episodes van IIR die hart teen 'n daaropvolgende langer periode
van isgemie beskerm. Hierdie endogene meganisme is die kragtigste vorm van
beskerming teen miokardiale infarksie tot dusver beskryf. Afgesien van isgemiese
prekondisionering (IPC), kan beskerming ook deur farmakologiese middels, soos
byvoorbeeld die aktivering van die beta-adrenerge reseptore met isoproterenol,
ontlok word. IPC beskerm die miokardium teen nekrose, arritmieë en apoptose, en
verhoog funksionele herstel na herperfusie. Daar is reeds aangetoon dat betaadrenerge
prekonsionering (~PC) post-isgemiese funksionele herstel verbeter,
maar dit is nog onbekend of beskerming ook teen miokardiale infarksie en
apoptose verleen word.
Die seintransduksie paaie betrokke tydens prekondisionering is reeds in detail
bestudeer. Daar word gewoonlik tussen faktore wat optree as snellers, of as
mediators van beskerming, onderskei. Snellers aktiveer sellulêre response voor die
aanvang van volgehoue isgemie, en hul betrokkenheid word aangetoon deurdat
inhibisie van snellers tydens die prekondisionering protokol, beskerming ophef.
Snellers se effekete kan ook ontlok word deur hulle tydelike toe te dien en dan net
voor volgehoue isgemie weer uit te was. Mediators oefen hulle effek tydens
volgehoue isgemie uit, en hulle betrokkenheid word gedemonstreer deurdat
toediening van inhibitors net voor volgehoue isgemie (sonder uitwas) hulle
beskermende effekte ophef. Mediators se rol kan ook aangetoon word deur te
poog om seintransduksie paaie tydens volgehoue isgemie te aktiveer. Aangesien
dit ontmoontlik is om middels tydens isgemie te infuseer, word aktiveerders
onmiddelik voor die aanvang van isgemie toegedien sonder om hulle uit te was,
sodat hulle effekte op beskerming vervolgens bestudeer kan word.
Dit is duidelik dat die evolusionêr-behoue stres geaktiveerde paaie tydens
prekondisionering betrokke is. Daar is drie paaie nl. die ekstrasellulêre reseptor
geaktiveerde pad (ERK), c-jun terminaal geaktiveerde kinases (JNK) en p38
mitogeen geaktiveerde proteïen kinases (MAPK). Die spesifieke rol van die p38
MAPK pad is nog nie ontrafel nie. Eksperimentele bewyse stel 'n rol vir die
aktivering van p38 MAPK as 'n sneller, sowel as 'n mediator van die beskermende
effek van prekondisionering, voor. Daar is egter ook sterk bewyse dat 'n afname in
p38 MAPK aktivering tydens volgehoue isgemie, eerder as sy aktivering, verantwoordelik is vir die waargenome beskermende effek. Verder is die rol van
p38 MAPK slegs in die konteks van beskerming teen nekrose, maar nie teen
apoptose nie, bestudeer.
DOELWITTE:
Die doelwit van hierdie studie was:
(I) Die vestiging van 'n prekondisionering model in neonatale kardiomiosiet in
selkultuur. Hierdie model sou potensieel 'n spoedige ontrafeling van die
seintransduksie paaie sonder die invloed van nie-kardiale selle bewerkstellig.
(II Om ondersoek in te stelof IPC en PPCteen nekrose en apoptose beskerm.
(III) Die ontrafeling van die rol van die stres geaktiveerde kinase, p38 MAPK,
tydens prekondisionering.
METODES:
1. Neonatale rot kardiomiosiet weefselkultuur model
'n Lewensvatbaarheids essai is ontwikkel deur van verskillende konsentrasies van
3-[4,5-dimetielthiazol-2-yl]-2,5-difeniel-tetrazolium bromied (MTT) gebruik te maak
- 'n konsentrasie van 0.25% was optimaalom lewensvatbaarheid te bepaal.
Neonatale kardiomiosiet weefselkulture is onderwerp aan volgehoue gesimuleerde
"isgemie" deur gebruik te maak van 5 mM KCN plus deoksiglukose (DOG) vir 5
minute of 45 min KCN. Sommige weefselkulture is geprekondisioneer deur middel
van chemiese isgemie (5 mM KCN vir 5 min) of van isoproterenol (10-7 M) vir 5 minute en 60 minute reoksigenasie alvorens dit bloot gestel is aan volgehoue
gesimuleerde isgemie.
2. Geïsoleerde volwasse rot kardiomiosiet model
Geïsoleerde kardiomiosiete is aan twee uur hipoksie blootgestel deur selle in 'n
pellet te sentrifugeer en met 'n dun lagie mineraalolie te bedek. Sommige groepe is
geprekondisioneer deur middel van 10 minute hipoksie by 37°C, of toediening van
isoproterenol (10-7 M) vir 5 minute gevolg deur 20 minute reoksigenasie. Die
tripaanblou uitsluitings metode en MTT metode soos ontwikkel in die neonatale
kardiomiosiet model is gebruik om lewensvatbaarheid te bepaal.
3. Geïsoleerde geperfuseerde volwasse rot hart model
3.1 Infarkgrootte is bepaal met 'n model van streeks isgemie deur van
tetrazolium kleuring gebruik te maak, waarna die area van nekrose (uitsluiting van
tetrazolium) as 'n presentasie van die risiko area bepaal is. Hierdie harte was
onderwerp aan 35 minute globale isgemie en 30 minute herperfusie. Sommige
groepe is geprekondisioneer met 3 siklusse van 5 minute globale isgemie, of die
toevoeging van isoproterenol (10-7 M) vir 5 minute, gevolg deur 5 minute
herperfusie voor die aanvang van volgehoue streeks isgemie.
3.2 p38 MAPK aktivering en merkers van apoptose: p38 MAPK aktivering is
bepaal deur gebruik te maak van anti-liggame teen tweeledige gefosforileerde p38
MAPK (d.w.s. geaktiveerde p38 MAPK). Apoptose is bepaal deur gebruik te maak van anti-liggame teen geaktiveerde kaspase-3, en teen 'n fragment van PARP
(PARP kliewing). Tydens hierdie eksperimente is geïsoleerde rotharte bloot gestel
aan 25 minute globale isgemie gevolg deur 30 minute herperfusie. Sommige
groepe is geprekondisioneer met drie siklusse van 5 minute globale isgemie. Om
voldoende weefsel vir Westerse klad tegnieke te verkry, is gebruik gemaak van 'n
globale isgemie model. As gevolg hiervan was 'n kort periode van volgehoue
isgemie genoodsaak, aangesien die globale isgemiese hart nie voldoende herstel
na 'n langer periode van isgemie nie, soos wat benodig word in streeks isgemiese
eksperimente.
3.3 Die rol van p38 MAPK tydens IPC is bepaal deur die toediening van 'n 1IJM
konsentrasie van SB 203580, 'n selektiewe inhibitor van p38 MAPK, hetsy tydens
prekondisionering (d.w.s. om die rol as 'n sneller te bepaal), óf vir 10 minute direk
voor die aanvang van volgehoue isgemie (d.w.s. om dus sy rol as mediator te
bepaal). Die tweede benadering was om anisomisien, 'n aktiveerder van p38
MAPK, as sneller (toediening vir 10 minute gevolg deur uitwassing) of as mediator
(10 minute direk voor aanvang van volgehoue isgemie) in dieselfde model as in die
geval van p38 MAPK aktiviteit bepaling, te gebuik. Die toediening van anisomisien
vir 10 minute het aangetoon dat dit p38 MAPK aktivering kan ontlok tot dieselfde
maate as die IPC protokol. Die eindpunte was infarkgrootte en merkers van
apoptose.
RESULTATE:
1. Neonatale rot kardiomiosiet weefselkultuur model
Dit was nie moontlik om 'n suksesvolle model met konsekwente resultate vir die
prekondisionering van neonatale kardiomiosiete te vestig nie. Daar is dus besluit
om af te sien van hierdie pogings en eerder 'n alternatiewe selmodel te gebruik.
2. Geïsoleerde volwasse rot kardiomiosiet model
Geïsoleerde volwasse kardiomiosiete is suksesvol geprekondisioneer, maar het te
min materiaalopgelewer vir die gelyktydige bepaling van sellewensvatbaarheid,
p38 MAPK aktivering en merkers vir apoptose. Daar is dus besluit om die
geïsoleerde geperfuseerde volwasse rothart te gebruik.
3. Geïsoleerde geperfuseerde volwasse rothart model
3.1 Beide IPC en PPCbeskerm teen infarksie en apoptose:
Deur gebruik te maak van twee prekondisionering modelle d.w.s. IPC en PPC, is
die beskermende effekte van prekondisionering teen infraksie (nekrose) oortuigend
gedemonstreer. Beide IPC en PPC het In betekenisvolle afname in infarkgrootle
veroorsaak (12.2 ± 1.4 en 15.2 ± 2.6% respektiewelik), vs Nie-PC harte (29.6 ±
2.9%)(p < 0.001). Beide vorme van prekondisionering het ook teen apoptose
beskerm deur die apoptose merkers, kaspase-3 aktivering en PARP kliewing te
verlaag. Die beskerming verkry deur beide vorms van prekondisionering is
geassosieer met In merkbare afname in die aktivering van p38 MAPK na
herperfusie. Die verband tussen p38 MAPK en die beskerming ontlok deur prekondisionering is gevolglik ondersoek, naamlik of p38 MAPK optree as 'n
sneller of as 'n mediator van beskerming. Om die rol van p38 MAPK as 'n mediator
of sneller tydens prekondisionering te ondersoek is daar gebruik gemaak van (I) 'n
spesifieke inhibitor van p38 MAPK aktivering nl. SB 203580 en (II) 'n bekende
aktiveerder van p38 MAPK nl. anisomisien.
3.2 p38 MAPK as 'n sneller vir beskerming:
Toediening van SB 203580 tydens die IPC protokol en uitwassing daarvan voor die
aanvang van volgehoue isgemie het nie die beskermende effek van IPC opgehef
nie, en het gelei tot 'n klein maar betekenisvolle verhoging in kaspase-3 aktivering
en PARP kliewing. Andersins het die aktivering van p38 MAPK met anisomisien vir
10 minute gevolg deur In uitwas ook tot In betekenisvolle afname in nekrose
(infarkgrootte 14.9 ± 2.2 vs 29.6 ± 2.9% in Nie-PC harte) (p < 0.001) in beide
merkers van apoptose gelei. Laasgenoemde resultate dui daarop dat p38 MAPK
inderdaad 'n mediator van prekondisionering is. Indien dit die geval is, waarom het
SB 203580 nie die beskermende effek van IPC opgehef nie? Die mees
waarskynlike verklaring is dat veelvuldige beskermingsmeganismes tydens 'n
multi-siklus protokol van IPC geaktiveer word, waarvan p38 MAPK aktivering slegs
een is. Dit is dus onwaarskynlik dat die inhibisie van p38 MAPK met SB 203580 die
aktivering van daardie meganismes onafhanklik van p38 MAPK sal blokkeer en
steeds in staat sal wees tot beskerming teen nekrose en apoptose. Dit is
interessant dat In klein verhoging in apoptose waargeneem is toe SB 203580
gebruik is onder hierdie toestande, aangesien dit daarop kan dui dat die beskerming teen apoptose meer afhanklik was van die aktivering van p38 MAPK
as die beskerming teen nekrose, siende dat geen effek op infarkgrootte
waargeneem is nie. 'n Verdere verklaring kan wees dat die bepaling van
infarkgrootte nie sensitief genoeg is om sulke klein effekte waar te neem nie.
3.3 p38 MAPK as 'n mediator vir beskerming:
Inhibisie van p38 MAPK aktivering deur SB 203580 toediening 10 minute voor
volgehoue isgemie het 'n betekenisvolle verlaging in infarkgrootte in vergelyking
met Nie-PC harte veroorsaak (12.6 ± 1.9 vs 29.6 ± 2.9%) (p < 0.001) soortgelyk
aan dié van harte geprekondisioneer met isgemie. Dit is geassosieer met In
soortgelyke patroon van beskerming teen apoptose, met betekenisvolle verlaagde
kaspase-3 aktivering en PARP kliewing.
Hierdie resultate ondersteun die rol van die afname van p38 MAPK aktivering as 'n
mediator van prekondisionering teen I/R-gemedieerde nekrose en apoptose. Die
resultate van die anisomisien eksperimente was met die eerste oogopslag nie in
oorstemming met hierdie gevolgtrekking nie. Die toedienning van die p38 MAPK
aktiveerder, anisomisien, vir 10 minute voor volgehoue isgemie het tot 'n
betekenisvolle beskerming teen nekrose aanleiding gegee (infarkgrootte 16.6 ± 2.4
vs 29.6 ± 2.9% in Nie-PC harte) (p < 0.01) en verlaagde kaspase-3 aktivering en
PARP kliewing wat dui op verlaagde apoptose. Die rede vir hierdie bevindings is
moontlik dat die metode van anisomisien toediening nie p38 MAPK geaktiveer het
tydens volgehoue isgemie nie, maar eintlik gedien het as 'n sneller vir beskerming teen isgemie - amper asof dit toegedien sou word sonder om uitgewas te word.
Ondersteuning vir hierdie aanname word gevind in die feit dat p38 MAPK
aktivering verlaag is na herperfusie. Hierdie resultate stel voor dat die logistiese
probleem dat In middel nie tydens isgemie toegedien kan word nie, nie oorkom kan
word deur onmiddelike voortydige infusie nie, en dat die toediening van
anisomisien op hierdie manier gelei het tot die aktivering van stroom-af effektors
van die p38 MAPK seintransduksie pad. 'n Belangrike kandidaat vir so 'n effektor is
"heat shock protein 27" (HSP27), wat reeds aangetoon is om 'n belangrike rol in
die beskerming teen apoptose en destabilisering, en dus die sitoskelet, te speel. 'n
Ander moontlikheid is dat anisomisien die JNK stres geaktiveerde kinases
geaktiveer het. Die ontrafeling van die rol van hierdie seintransduksie pad
noodsaak die gebruik van anisomisien in die teenwoordigheid van 'n agent soos
curcumin, 'n JNK inhibitor.
Finale gevolgtrekking:
Die werk soos vervat in hierdie tesis toon aan dat die stres geaktiveerde kinase,
p38 MAPK, betrokke is in die beskermings effek van isgemiese prekondisionering.
Die resultate dui op 'n rol vir die aktivering van p38 MAPK as 'n sneller vir
beskerming, en die afname in p38 MAPK as 'n mediator vir beskerming, soos
waargeneem in die vermindering van veranderlikes van beide nekrose
(infarkgrootte) en apoptose soos bepaal deur kaspase-3 aktivering en PARP
kliewing.
|
26 |
Disparidades do acesso às terapias de reperfusão e mortalidade entre pacientes com IAMCSST da região não metropolitana e metropolitana de Aracaju / Disparities in access to reperfusion therapies among patients with STEMI of the non-metropolitan and metropolitan region of AracajuArcelino, Larissa Andreline Maia 03 August 2018 (has links)
Background: Patients residing or starting symptomatology for AMI in non-metropolitan areas face numerous obstacles in accessing health care. These may be less likely to receive evidence-based therapies and experience worse outcomes, little is known about indicators of quality of care, particularly in non-metropolitan regions in Sergipe.
Aims: To compare the speed of access to the hospital with angioplasty, use of reperfusion therapies and 30-day mortality among patients with STEMI who started the symptoms in the non-metropolitan region with those who started in the metropolitan region of Sergipe state.
Method: Data from the VICTIM Study (VIa Crucis for the Treatment of Myocardial Infarction) were used from December 2014 to October 2017. The sampling was done for convenience using Pearson's χ2 test and Student's T-test for analysis of the data, a significance level of 5% was adopted.
Results: 878 patients participated in the study, of which 382 patients started the symptoms in the metropolitan region and 496 in the non-metropolitan region. Males were predominant in both groups. Patients from the non-metropolitan region presented higher age (63 ± 13 years vs. 60 ± 12, p = 0.001) and higher mean GRACE score (146 vs.140 p <0.001). In addition, they traveled more distances (104 ± 58km vs. 16 ± 49km, p <0.001), went through more than 1 institution (96% vs. 73%, p <0.001) and had a longer delay acess to hospital with angioplasty (11h [7-26] vs. 7h [3-17], p< 0,001) and consequently lower percentage received primary angioplasty (45% vs. 59%, p <0.001). Higher mortality of 30 days (14% vs. 8%, p 0.004) was evidenced in the population of this region when compared to patients in the metropolitan region. In addition, in the full multivariate model, the odds ratio for 30-day mortality for the non-metropolitan group was also higher (OR 1.84, 95% CI, 1.12 to 3.04, p = 0.016).
Conclusion: We observed disparities in access, use of reperfusion therapies and 30-day mortality rates among patients who started the symptoms in the non-metropolitan region when compared to those of the metropolitan in Sergipe. These findings may help in the better design of the care line for patients with STEMI, especially regarding the logistics of access to reperfusion therapies in Sergipe. / Introdução: O IAMCSST requer tratamento imediato para preservar o músculo e reduzir mortalidade. Pacientes que iniciam sintomatologia para IAM em regiões não metropolitanas podem ser menos propensos a receber terapias baseadas em evidências e, portanto experimentar piores resultados. Contudo, há escassez de estudos sobre os indicadores de qualidade assistencial particularmente nesta população no Brasil.
Objetivo: Comparar a celeridade do acesso ao hospital com disponibilidade para intervenção coronariana percutânea (ICP), uso das terapias de reperfusão e mortalidade em 30 dias entre os pacientes com IAMCSST que iniciaram os sintomas na região não metropolitana com aqueles que iniciaram na região metropolitana do estado de Sergipe.
Método: Utilizou-se dados do Estudo VICTIM (VIa Crucis para Tratamento do Infarto do Miocárdio), realizado no período de dezembro de 2014 a setembro de 2017. A amostragem foi feita por conveniência, utilizando teste χ2 de Pearson e T-Student para análise dos dados, foi adotado nível de significância de 5%.
Resultados: Participaram do estudo 878 voluntários, dos quais 382 pacientes iniciaram os sintomas na região metropolitana e 496 na região não metropolitana. O sexo masculino foi predominante em ambos os grupos. Os pacientes da região não metropolitana apresentam maior idade (63±13anos vs. 60 ± 12, p=0,001) e maior média de GRACE score (146 vs.140 p<0,001). Além disso, percorreram maiores distâncias (104± 58km vs. 16±49km, p < 0,001), passaram por mais de 1 instituição (96% vs. 73%, p< 0,001), apresentam maior atraso até o hospital com ICP (11h [7-26] vs. 7h [3-17], p< 0,001) e, portanto, realizaram menos ICP primária (45% vs. 59%, p<0,001). Constatou-se ainda que, aqueles da região não metropolitana comparativamente a metropolitana apresentaram maior mortalidade em 30 dias (14% vs. 8%, p. 0,004) e, no modelo multivariado completo, mais chance de morte aos 30 dias (OR 1,84, IC 95%, 1,12 a 3,04, p = 0,016).
Conclusão: Observou-se disparidades no acesso, no uso das terapias de reperfusão e nas taxas de mortalidade de 30 dias entre pacientes que iniciaram os sintomas na região não metropolitana quando comparados com os da metropolitana em Sergipe. Esses achados podem auxiliar no melhor delineamento da linha de cuidado aos pacientes com IAMCSST, principalmente no que tange à logística de acesso às terapias de reperfusão em Sergipe. / Aracaju, SE
|
27 |
Possible mechanisms for levosimendaninduced cardioprotectionGenis, Amanda 12 1900 (has links)
Thesis (MScMedSc (Biomedical Sciences. Medical Physiology))--Stellenbosch University, 2008. / Background and purpose. To limit ischaemic injury, rapid restoration of coronary
blood flow is required, which will in turn reduce infarct size. However, reperfusion
itself causes myocyte death – a phenomenon termed lethal reperfusion-induced
injury, which limits protection of the ischaemic myocardium. Thus the reperfusion
of irreversibly damaged myocytes may accelerate the process of cell necrosis.
Additive protection of the ischaemic myocardium in the form of adjunct therapy
remains a topic of intensive research. Levosimendan, a calcium sensitizing agent
with positive inotropic effects has in several studies been found to alleviate the
damaging effects of reperfusion injury. Levosimendan has been shown to be a
KATP channel opener. These channels have been implicated to play an important
role in ischaemic preconditioning (IPC). With this knowledge, the aim of this study
was to determine whether levosimendan and IPC have certain cardioprotective
mechanisms in common and whether protection with pharmacological
preconditioning could be elicited with levosimendan. In this study, we investigated
whether: 1) the isolated guinea pig heart could be protected by ischaemic
preconditioning (IPC) and postconditioning (IPostC), 2) the heart could be
pharmacologically pre- and postconditioned, using levosimendan (LPC & LPostC),
3) a combination of IPC & LPC had an additive protective effect on the heart, 4)
the KATP (both mitochondrial and sarcolemmal) channels are involved in this
protection and 5) the pro-survival kinases of the RISK (reperfusion injury salvage
kinase) pathway are involved.
Experimental approach. Isolated perfused guinea pig hearts were subjected to
three different IPC protocols (1x5, 2x5 and 3x5 minutes of ischaemia) or
levosimendan (0.1μM) preconditioning, before coronary artery occlusion (CAO –
40min@36.5ºC), followed by 30 minutes of reperfusion. Hearts were also
subjected to a combination of IPC & LPC, to establish whether they had additive
protective effects. In addition, hearts were pre-treated with levosimendan directly
before induction of sustained ischaemia (without washout of the drug –
levosimendan pre-treatment (LPT)) for 10min. With the postconditioning protocol,
iii
the hearts were subjected to 3x30second cycles of ischaemia/reperfusion or
levosimendan/vehicle. In a separate series of experiments, hearts were treated
with KATP channel blockers (for both sarcolemmal & mitochondrial), before LPC,
LPT and LPostC. The endpoints that were measured were: cardiac reperfusion
function, myocardial infarct size and RISK pathway expression and
phosphorylation (PKB/Akt and extracellular signal-regulated kinase – ERK42/44).
Results. IPC, IPostC, LPC & LPostC decreased myocardial infarct size
significantly compared with their controls (21.9±2.2%, 21.4±2.2%, 20.6±3.1% and
20.6±1.8% respectively vs. 46.4±1.8% for controls, p<0.05). The combination of
IPC & LPC had no additive protective effect. Pre-treating the hearts with
levosimendan (without washout), before index ischaemia, proved to be the most
effective method of cardioprotection (infarct size: 5.8±0.9% vs. 46.4±1.8% for
controls, p<0.001). With LPT a significant increase (p < 0.05 vs. control) in
phosphorylation of ER42/44 was also observed. An increase in the activity of one
of the RISK pathway kinases, ERK42/44 seems to be one of the reasons for LPT’s
efficacy. Treating the hearts with KATP channel blockers before subjecting them to
LPC, LPT & LPostC abolished the protective effects induced by levosimendan,
suggesting a role for the sarcolemmal and mitochondrial KATP channels in
levosimendan-induced cardioprotection.
Conclusions and implications. 1) Isolated guinea pig hearts could be pre- and
postconditioned within the setting of ischaemia, 2) Hearts could be
pharmacologically pre- and postconditioned with levosimendan, 3) levosimendan
pre-treatment is the most effective way to reduce infarct size, possibly acting by
increasing the phosphorylation of ERK42/44, 4) Myocardial protection was not
increased by combining IPC & LPC (suggesting similar mechanisms of protection),
5) LPC, LPT and LPostC were abolished by both sarcolemmal and mitochondrial
KATP channel blockers.
.LPC and especially LPT, could be useful before elective cardiac surgery while
LPostC may be considered after acute coronary artery events.
|
28 |
The role of calcium and calcium antagonists in the reperfusion injury of the heartConradie, Suzanne Louise January 2005 (has links)
Thesis (PhD)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: The reperfusion injury after myocardial ischemia is relevant in the clinical setting,
after cardiopulmonary bypass for cardiac surgery, after PTCA and stenting and
after cardiopulmonary resuscitation. The components of the reperfusion injury
considered in this study were myocardial stunning and reperfusion arrhythmias.
Calcium antagonists have been shown to be beneficial in attenuating the
myocardial reperfusion injury in the in vitro and in vivo laboratory setting
(Lamping, Gross 1985, Przyklenk and Kloner 1988, Taylor 1990, Ehring 1992,
Gross and Piper 1992). However systemic administration of a dose of calcium
antagonist, large enough to attenuate the myocardial reperfusion injury in the
clinical setting, would inevitably lead to unwanted systemic side effects of the
drug.
The aim of this study was to investigate the hypothesis that an adequate dose of
verapamil administered timeously, directly into the ischemic myocardium, would
attenuate the reperfusion injury, either when administered from the onset of
ischemia, or from 3 minutes before reperfusion.
The anesthetized open chest porcine model of myocardial ischemia (15 min total
LAD occlusion) and reperfusion was employed in this study. A low dose of
verapamil (0.5 mg/8mt or 0.0625mg/mt), a high dose of verapamil (2mg/8m or O.25mg/ml), or vehicle (saline) (8ml) was infused over 8 minutes, directly into
the LAD coronary artery supplying the ischemic segment. The infusion was
started either at the onset of ischemia, or from 3 minutes before reperfusion.
The time taken for the various parameters to return to pre ischemic values was
compared between the different groups.
The results showed that the high dose of verapamil (2mg) attenuated the
reperfusion injury both when administered from the onset of ischemia, and when
administered from 3 minutes before reperfusion, compared to either the low dose
of verapamil, or the saline infusions. The high dose of verapamil groups had a
faster recovery of both systolic contractile function and diastolic function and a
lower incidence of ventricular fibrillation on reperfusion. There were no systemic
effects of verapamil infusion in any of the groups.
The clinical setting of cardiac surgery expressly lends itself to the clinical
application of this finding. There is direct access to the coronary arteries both
before ischemia and before reperfusion. A small dose of calcium channel
blocking drug, with no systemic effect can be administered into the aortic root at
the onset of ischemia, just prior to cardioplegia (when the heart is still warm),
and after rewarming a few minutes prior to removal of the aortic cross clamp. / AFRIKAANSE OPSOMMING: Die reperfusie besering na miokardiale isgemie is klinies relevant na
kardiopulmonêre omleiding vir hart chirurgie, na kardiologiese PTKA en stut
prosedures en na kardiopulmonale ressussitasie. Die komponente van die
reperfusie besering wat in hierdie studie oorweeg is, is miokardiale tydelike
omkeerbare onderdrukking (stunning) en reperfusie arritmieë.
Kalsium antagoniste is gewys om effektief te wees in beperking van die
reperfusie besering in beide in vitro en in vivo laboratorium eksperimente
(Lamping, Gross 1985, Przyklenk en Kloner 1988, Taylor 1990, Ehring 1992,
Gross en Piper 1992). Sistemiese toediening van 'n dosis kalsium kanaal
blokker, voldoende om die miokardiale reperfusie besering in die pasiënt te
beperk, lei egter tot ongewenste sistemiese newe effekte van die middel.
Die doel van die studie was om die hipotese te ondersoek dat 'n voldoende dosis
verapamil, wat betyds direk toegedien is aan die isgemiese miokardium, die
reperfusie besering sal beperk, ongeag of dit toegedien is vanaf die begin van
isgemie, of van 3 minute voor reperfusie.
Die vark model van miokardiale isgemie en reperfusie is aangewend in die studie.
Die varke was tydens die eksperiment onder narkose, met die borskas oop, en
15 minute totale LAD okklusie is toegepas. 'n Lae dosis verapamil (0.5mg/8ml of 0.0625 mg/mt), of hoë dosis veraparnil (2mg/8mt of 0.25mg/mt), of saline
(8mt) is oor 8 minute toegedien direk in die LAD arterie wat die isgemiese
segment voorsien. Die infuus is begin direk na die aanvang van isgemie, of 3
minute voor die aanvang van reperfusie. Die tyd geneem vir terugvoer van
parameters na pre isgemiese waardes is tussen die groepe vergelyk.
Die resultate toon dat die hoë dosis veraparnil die reperfusie besering beperk in
vergelyking met die lae dosis veraparnil of saline infusies, ongeag of dit van die
begin van isgemie, of van 3 minute voor reperfusie toegedien word. Die groepe
wat die hoë dosis veraparnil ontvang het, het vinniger herstel van sistoliese en
diastoliese funksie getoon en het'n laer insidensie van reperfusie disritmieë,
gewys. Geen sistemiese effekte van veraparnail infuus is waargeneem nie.
Die kliniese toepassing van hierdie bevinding is by uitstek geskik vir toepassing
tydens kardiopulmonale omleiding by kardiale chirurgie. Daar is direkte toegang
tot koronêre arteries voor isgemie en voor reperfusie. 'n Klein dosis kalsium
antagonis, met weglaatbare sistemiese effekte, kan toegedien word in die aorta
wortel met die aanvang van isgemie, net voor kardioplegie toediening (hart
steeds warm), en na verwarming, 'n paar minute voor verwydering van die aorta
kruis klem.
|
29 |
Lactobacillus helveticus R0052 et Bifidobacterium longum R0175 en combinaison réduisent l’apoptose dans le système limbique après ischémie myocardique transitoire chez le ratGirard, Stéphanie-Anne 04 1900 (has links)
Nous avons démontré la présence d'apoptose dans le système limbique suivant un infarctus du myocarde. Cette mort cellulaire serait partiellement reliée à l'augmentation de cytokines pro-inflammatoires. Des études démontrent que certains probiotiques ont des effets bénéfiques en diminuant le ratio de cytokines pro/anti-inflammatoires. La prise de probiotiques en prévention, avant l’occlusion d’une artère coronarienne, pourrait-elle diminuer l’apoptose dans le système limbique? Méthodes : La combinaison de probiotiques Lactobacillus helveticus R0052 et Bifidobacterium longum R0175 ou son
véhicule fut additionné dans l’eau des rats pendant 28 jours consécutifs. Un infarctus du myocarde fut provoqué par l’occlusion de l’artère coronaire gauche. Après 40 minutes
d'occlusion, les régions ischémiques ont été reperfusées pour 72 heures. Les animaux furent sacrifiés et la taille de l'infarctus mesurée. L'amygdale et l'hippocampe furent prélevés pour déterminer l'activité de la caspase-3 (pro-apoptotique), le ratio Bax/Bcl2(proapoptotique/
anti-apoptotique) et l'activité d'Akt (survie cellulaire). Résultats : La taille de l’infarctus n'est pas diminuée dans le groupe probiotique (45% de la région à risque)comparé au groupe placebo. Nos marqueurs d’apoptose démontrent une diminution dans les régions du gyrus denté, de l’amygdale latérale et médiane dans le groupe probiotique par rapport au placebo. L’activité de la caspase-3 et le ratio Bax:Bcl2 furent réduits dans le groupe probiotique de 50% et 40% respectivement (p < 0.05) et phosphorylation d’Akt fut augmentée de 35% (p<0.05). Aucune différence fut observée pour les régions Ca1 et Ca3. Conclusion : La combinaison de probiotiques utilisée réduit l’apoptose dans différentes régions du système limbique 72 heures après un IM. / Apoptosis is observed in limbic system after a myocardial infarction (MI). This cell death is due to the release of pro-inflammatory cytokines. Since probiotics reduce the pro/anti-inflammatory cytokine ratio, we hypothesise that probiotics will lessen apoptosis in the limbic system following MI. Methods: Rats were given probiotics or placebo for 4 consecutive weeks. Rat in the probiotic group received a daily dose of over 1 billion live bacterial cells of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 in
combination. A MI was then induced in anesthetised rats by a 40-minute occlusion of the left anterior coronary artery followed by a 72 hours of reperfusion. Infarct size was measured and apoptosis was determined in the amygdala and hippocampus in both groups. Results: Infarct size was not diminished in the probiotic group (45% of the risk area), apoptosis was lessened in the dentate gyrus (DG), the lateral (LA) and medial (MA)amygdala compared to the placebo group. Caspase-3 and Bax/Bcl2 ratio were reduced in the probiotic group by about 50% and 40% respectively. Akt activity was increased by 35% in these regions. No difference was observed in the hippocampus Ca1 and Ca3 regions. Conclusion: This probiotic combination can reduce the apoptosis found in specific regions of the limbic system following a MI, which may have significance for post-MI depression.
|
30 |
Efeito dos novos antiagregantes plaquetários prasugrel e ticagrelor administrados upstream sobre os achados angiográficos da angioplastia primária / Effect of new antiplatelet prasugrel and ticagrelor upstream therapy, on angiographic results of primary percutaneous coronary interventionMont\'Alverne Filho, José Ronaldo 03 August 2015 (has links)
Introdução. A dupla antiagregação plaquetária traz benefícios no tratamento do infarto agudo do miocárdio com supradesnivelamento do segmento ST (IAMSST). Há variabilidade intra e interindividual no uso do clopidogrel e isso influencia no benefício do seu uso nesse grupo de pacientes. O objetivo desta pesquisa foi avaliar os efeitos de novo antiagregantes plaquetários (prasugrel e ticagrelor) administrados na sala de emergência (\"upstream\") sobre o resultado angiográfico da angioplastia primária, levando em conta o fluxo coronariano TIMI, o blush miocárdico e a carga de trombo. Métodos. Foi realizado um ensaio clínico, randomizado, cego, com 131 pacientes admitidos com IAMSST. Todos os pacientes receberam ácido acetilsalicílico (AAS). Os pacientes foram randomizados para receber clopidogrel (n=44), prasugrel (n=41) ou ticagrelor (n=46) como dose de ataque ainda na emergência. Todos os pacientes foram submetidos a aspiração manual de trombos. Ao término do procedimento, o resultado angiográfico foi avaliado quanto ao fluxo TIMI, o blush miocárdico e a carga de trombo. Resultados. O fluxo coronariano TIMI >= 1 antes do procedimento foi observado mais frequentemente com o uso de ticagrelor (n = 10, 21,7%) do que com o clopidogrel (n = 1, 2,3%) e prasugrel (n = 5, 12,2%; p = 0,019). O fluxo TIMI coronária no fim do procedimento não diferiu significativamente entre os grupos (p = 0,101). Melhor resultado no que diz respeito ao blush miocárdico foi observada com prasugrel, que produziu um grau de blush III em 85,4% (n = 35) dos pacientes, em comparação com o clopidogrel (54,5%; n = 24) e ticagrelor (67,4%; n = 31; p = 0,025). A carga de trombo pré-procedimento foi maior no grupo de clopidogrel, em que 97,7% (n = 43) dos casos denotaram carga de trombo grau 4/5, enquanto 87,8% (n = 36) do grupo prasugrel tiveram respostas semelhantes, e 80,4% (n = 37) foram observadas no grupo ticagrelor (p = 0,03). Conclusão. Os novos antiagregantes plaquetários ticagrelor e prasugrel parecem exercer efeito sobre o resultado angiográfico dos pacientes submetidos a angioplastia primária. O uso do ticagrelor propiciou menor carga de trombo e um fluxo TIMI melhor no pré-procedimento e o uso do prasugrel ensejou melhor perfusão miocárdica analisada pelo blush miocárdico. Não houve diferença no fluxo angiográfico TIMI pós procedimento / Introduction. Dual antiplatelet therapy has benefits in the treatment of acute myocardial infarction with ST-segment elevation (STEMI). There is variability intra and inter individual in the use of clopidogrel and this influences the benefit of its use in this group of patients. The objective of this research was to evaluate the angiographic results of Upstream Clopidogrel, Prasugrel, or Ticagrelor For Patients Treated With Primary Angioplasty. Methods. A clinical trial was conducted, randomized, double blind, with 131 patients admitted with STEMI. All patients received acetylsalicylic acid (ASA). Patients were randomized to receive clopidogrel (n = 44), prasugrel (n = 41) or ticagrelor (n = 46) as loading dose even in emergency. All patients were submitted to manual thrombus aspiration. At the end of the procedure, the angiographic result was evaluated for TIMI flow, myocardial blush and thrombus burden. Results. A coronary TIMI flow >= 1 before the percutaneous procedure was observed more frequently with the use of ticagrelor (n=10, 21.7%) than with clopidogrel (n=1, 2.3%) and prasugrel (n=5, 12.2%; p=0.019). The coronary TIMI flow at the end of the procedure did not significantly differ between the groups (p=0.101). A better result with respect to myocardial blush was observed with prasugrel, which yielded a blush grade of III in 85.4% (n=35) of patients, compared with clopidogrel (54.5%; n=24) and ticagrelor (67.4%; n=31; p=0.025). The pre-procedural thrombus burden was found to be of a higher grade in the clopidogrel group, in which 97.7% (n=43) of the cases exhibited thrombus burdens grade 4/5, whereas 87.8% (n=36) of the prasugrel group had similar responses, and 80.4% (n=37) were observed in the ticagrelor group (p=0.03). Conclusions. The novel antiplatelet agents represented by ticagrelor and prasugrel appear to have effect on the angiographic outcome of patients undergoing primary angioplasty. The use of ticagrelor led to a smaller thrombus burden and better TIMI flow at the beginning of the procedure and the use of prasugrel produced a better myocardial perfusion analyzed by myocardial blush. There was no difference in post angioplasty TIMI flow
|
Page generated in 0.1174 seconds