Arresto Cardioplegico con una soluzione arricchita di Urocortina. Modello in vivo e confronto nel ratto diabetico e non diabetico

RIASSUNTO La protezione del miocardio in cardiochirurgia sar\ue0 sempre uno dei pi\uf9 importanti momentI per il chirurgo quando decide di operare al cuore un paziente. Sempre tenendo presente che questa procedura dovrebbe puntare a migliorare la qualit\ue0 della vita del paziente, soprattutto in coloro che mostrano, (gi\ue0 prima dell'operazione), un certo grado di deficit contrattile. I risultati contrastanti di studi sperimentali negli ultimi dieci anni, ancora una volta sollevano molti dubbi sulla efficacia delle varie soluzioni cardioplegiche utilizzate in ambito clinico. Una soluzione alla controversia pu\uf2 risultare solo da una migliore comprensione dei concetti fondamentali del metabolismo del muscolo cardiaco del danno da ischemia e riperfusione durante l'arresto cardioplegico. La ricerca di base \ue8 quindi non solo utile, ma necessaria e indispensabile per tentare di risolvere questi dubbi, applicando modelli sperimentali che siano il pi\uf9 vicino possibile alla realt\ue0 clinica, come \ue8 avvenuto nel nostro modello sperimentale. Recenti studi hanno dimostrato una certa attivit\ue0 metabolica cellulare anche durante l'arresto cardiaco indotto dopo somministrazione di una soluzione cardioplegica, dimostrando in tal modo la necessit\ue0 e l'utilit\ue0 di aggiungere addittivi alle soluzioni cardioplegiche standard, tali da migliorare la protezione stessa. Altri studi hanno dimostrato la superiorit\ue0 della cardioplegia con sangue, quale veicolo fondamentale, rispetto alle soluzioni cristalloidi, soprattutto per le migliori caratteristiche fisiologiche. Per quanto riguarda la temperatura e le vie di somministrazione per indurre l'arresto cardiaco ci\uf2 rimane ancor oggi a discrezione del chirurgo. Abbiamo gi\ue0 dimostrato in studi precedenti, che l'arresto cardioplegico induce la sovraespressione di UCN endogena e che l'aggiunta di UCN nella soluzione cardioplegica infusa nel ratto diabetico verso i casi di controllo probabilmente induce sia a, livello di mRNA che a livello proteico una colocalizzazione della PKCepsilon con la sua successiva traslocazione mitocondriale ci\uf2 inducendo una migliore sopravvivenza dei miociti contro la morte cellulare per apoptosi. Considerando che la perdita e / o la compromissione funzionale dei miociti dopo l'arresto cardioplegica \ue8 causa nota di riduzione della contrattilit\ue0 cardiaca e conseguente aumento della mortalit\ue0 e morbilit\ue0, i dati funzionali rilevati con cateteri a conduttanza sembrano poter ridurre l'entit\ue0 della disfunzione cardiaca se contrapposti al gruppo di controllo che aveva ricevuto una cardioplegia priva di UCN. Questa strategia che abbiamo applicato nello studio \ue8 propositiva allo studio di soluzioni cardioplegiche attraverso la supplementazione di UCN esogena, promettente per ridurre il rischio di disfunzione cardiaca e l'apoptosi delle cellule miocitiche dopo intervento chirurgico nei pazienti esposti ai danni da I / R associati all'arresto cardioplegica.The protection of the myocardium in cardiac surgery will always be one of the most important and of concern moment for the surgeon when deciding to operate on a patient. Always keeping in mind that this procedure should aim to improve the quality of life of the patient, especially in those who show, (already before the operation), a certain degree of contractile deficit. The conflicting results of experimental studies in the last decade again raise many doubts about their effectiveness in the clinical setting. A solution to the dispute may only result from a better understanding of the fundamental concepts on the metabolism of the heart muscle and damage by ischemia and reperfusion injury during cardioplegic arrest. Basic research is therefore not only useful, but necessary and indispensable to try to resolve these doubts by applying experimental models that are as close as possible to clinical reality, as occurred in our experimental model. Recent studies have shown a certain cellular metabolic activity even during cardiac arrest induced with cardioplegic solution, thus demonstrating the need to add to a standard cardioplegic solutions , appropriate substrates that acts to improve the protection itself. Other studies have also demonstrated the superiority of blood cardioplegia compared to crystalloid, especially for its more physiological features. As regards the temperature and the routes of administration to induce cardiac arrest remains at the discretion of the surgeon. We have shown that the cardioplegic arrest induces overexpression of endogenous UCN and the addition of UCN in the cardioplegic solution infused in diabetic rat versus control probably induces both at, mRNA level and at protein level a colocalization of PKCepsilon with mitochondrial translocation, inducing the survival of myocytes against cell death by apoptosis. Whereas the loss and / or functional impairment of myocytes after cardioplegic arrest is known to cause reduction of cardiac contractility and resulting in increased mortality and morbidity, functional data measured with conductance catheter appear to reduce the extent of cardiac dysfunction if opposed to the control group that had received a cardioplegia devoid of UCN. This strategy is a proposed cardioplegic solutions supplementation with exogenous UCN that seems to be promising to reduce the risk of cardiac dysfunction and cell apoptosis after surgery in patients exposed to damage from I / R associated with cardioplegic arrest

Role of calcium desensitization in the treatment of myocardial dysfunction after deep hypothermic circulatory arrest

Abstract Introduction Rewarming from deep hypothermic circulatory arrest (DHCA) produces calcium desensitization by troponin I (cTnI) phosphorylation which results in myocardial dysfunction. This study investigated the acute overall hemodynamic and metabolic effects of epinephrine and levosimendan, a calcium sensitizer, on myocardial function after rewarming from DHCA. Methods Forty male Wistar rats (400 to 500 g) underwent cardiopulmonary bypass (CPB) through central cannulation and were cooled to a core temperature of 13°C to 15°C within 30 minutes. After DHCA (20 minutes) and CPB-assisted rewarming (60 minutes) rats were randomly assigned to 60 minute intravenous infusion with levosimendan (0.2 μg/kg/min; n = 15), epinephrine (0.1 μg/kg/min; n = 15) or saline (control; n = 10). Systolic and diastolic functions were evaluated at different preloads with a conductance catheter. Results The slope of left ventricular end-systolic pressure volume relationship (Ees) and preload recruitable stroke work (PRSW) recovered significantly better with levosimendan compared to epinephrine (Ees: 85 ± 9% vs 51 ± 11%, P\u3c0.003 and PRSW: 78 ± 5% vs 48 ± 8%, P\u3c0.005; baseline: 100%). Levosimendan but not epinephrine reduced left ventricular stiffness shown by the end-diastolic pressure-volume relationship and improved ventricular relaxation (Tau). Levosimendan preserved ATP myocardial content as well as energy charge and reduced plasma lactate concentrations. In normothermia experiments epinephrine in contrast to Levosimendan increased cTnI phosphorylation 3.5-fold. After rewarming from DHCA, cTnI phosphorylation increased 4.5-fold in the saline and epinephrine group compared to normothermia but remained unchanged with levosimendan. Conclusions Levosimendan due to prevention of calcium desensitization by cTnI phosphorylation is more effective than epinephrine for treatment of myocardial dysfunction after rewarming from DHCA

Cardioprotective effects of sphingosine-1-phosphate receptor immunomodulator fty720 in a clinically relevant model of cardioplegic arrest and cardiopulmonary bypass

Objective: FTY720, an immunomodulator derived from sphingosine-1-phosphate, has recently demonstrated its immunomodulatory, anti-inflammatory, anti-oxidant, anti-apoptotic and anti-inflammatory properties. Furthermore, FTY720 might be a key pharmacological target for preconditioning. In this preclinical model, we have investigated the effects of FTY720 on myocardium during reperfusion in an experimental model of cardioplegic arrest (CPA) and cardiopulmonary bypass. Methods: 30 Sprague-Dawley rats (300-350 g) were randomized into two groups: Group-A, treated with FTY720 1 mg/kg via intravenous cannulation, and Group-B, as control. After 15 min of treatment, rats underwent CPA for 30 min followed by initiation of extracorporeal life support for 2 h. Support weaning was done, and blood and myocardial tissues were collected for analysis. Hemodynamic parameters, inflammatory mediators, nitro-oxidative stress, neutrophil infiltration, immunoblotting analysis, and immunohistochemical staining were analyzed and compared between groups. Results: FTY720 treatment activated the Akt/Erk1/2 signaling pathways, reduced the level of inflammatory mediators, activated antiapoptotic proteins, and inhibited proapoptotic proteins, leading to reduced nitro-oxidative stress and cardiomyocyte apoptosis. Moreover, significant preservation of high-energy phosphates were observed in the FTY720-treated group. This resulted in improved recovery of left ventricular systolic and diastolic functions. Conclusion: The cardioprotective mechanism in CPA is associated with activation of prosurvival cell signaling pathways that prevents myocardial damage. FTY720 preserves high-energy phosphates attenuates myocardial inflammation and oxidative stress, and improves cardiac function

CARATTERIZZAZIONE DEL MICROBIOTA ORALE E DI BIOPSIE DI TESSUTO VALVOLARE PATOLOGICO IN UN CAMPIONE DI PAZIENTI PARODONTALI E NON PARODONTALI

Aim. To assess the prevalence of periodontal disease among patients presenting severe heart valve impairment and requiring coronary by-pass surgery. To investigate the presence of periodontal pathogens in cardiovascular specimens and to analyse the relationship between oral and cardiovascular patterns of the microorganisms detected. Materials and Methods. An observational study was conducted at the Cardiovascular Surgery Division, University Hospital of Verona, Verona, Italy. The Ethical approval was previously obtained in order to enroll subjects referring to the Hospital for heart valves replacement and coronary bypass surgery. Patients were scheduled to be visited by a dentist, together with a dental hygienist, the day before the surgery: periodontal conditions were accurately registered through clinical and radiographic examinations and dental plaque or salivary samples were collected. Cardiovascular specimens were collected during surgical heart valve replacement for the scheduled microbiological 16 rRNA gene sequencing. Plaque samples and cardiovascular specimens were analyzed according to periodontal status. A qualitative comparison between oral and cardiovascular profiles of the microorganisms detected was also performed. Results. 26 patients (15 men and 11 women) attended the study. The overall number of patients examined for the conditions of soft tissues were 19, as 7 patients were edentulous and reported to had lost dentition for history of periodontal disease. 46.15% and 11.54% individuals respectively presented moderate periodontitis and severe periodontitis. A statistically significant difference (p=0.04) was found for PPD between healthy patients, patients with moderate periodontitis and patients with severe periodontitis. Regarding plaque samples and cardiovascular specimens, no statistically significant differences were found in both cases between healthy patients, patients with moderate periodontitis, patients with severe periodontitis and edentulous patients. Nine valves were found to be positive at the presence of oral and periodontophatic bacterial DNA. The principal species detected were Streptococcus periodonticum, Streptococcus mutans, Fusobacterium nucleatum-periodonticum, Aggregatibacter segnis and Porphyromonas pasteri. Conclusions. The significant number of oral and periodontopathic bacterial DNA species found in valve tissue samples, in patients with periodontitis, suggests that the presence of these microrganisms in valve tissue seems to be not coincidental, and that they may have a role in the development of vascular diseases

G-CSF displays restricted ability to promote Sca-1(+) cardiac stem cell proliferation in vitro

Granulocyte colony-stimulating factor (G-CSF) is a controversial chemical in cardiac cell therapy. Myocardial homing of mobilized bone marrow-derived cells is thought to play a critical role in observed G-CSF-induced cardiac repair; meanwhile, the activation of proliferative potential of cardiac stem cells (CSCs) residing in the heart is a significant challenge. The present study aims to investigate whether G-CSF receptor is expressed in adult resident Sca-1(+) CSCs and determine the effect of G-CSF treatment on the proliferation of CSCs. For cardiac cells isolation, 12-week-old male C57BL/6 mice were anesthetized in a chamber containing 2.5 % isoflurane in oxygen, euthanized by CO2 inhalation and then sacrificed by cervical dislocation. Magnetic-activated cell sorting was employed to acquire highly purified Sca-1(+) CSCs. We found that G-CSF receptor was expressed in adult resident Sca-1(+) CSCs by immunofluorescence staining and Western blotting. Exposure of Sca-1(+) cells to G-CSF in the culture medium for 72 h induced time-dependent but self-limiting cell cycle acceleration with a restricted effect on the CSC proliferation. As a result, it has provided a new insight to focus on the association between cardiac G-CSF therapy and adult resident stem cell activation. It may suggest gaining a deeper insight into the mechanisms of the interaction between CSCs and G-CSF to develop a synergistic strategy based on resident stem cell and G-CSF therapy for heart disease

Hemodynamic Analysis of Efficacy of Pulsatile Perfusion During Cpb With A New Centrifugal Pump

Objectives: New models of centrifugal pumps are claimed to have better hemodynamic performance in pulsatile perfusion during CPB. Few data are available for hemodynamic evaluation of these pumps in vivo, especially in highrisk groups as elderly patients. The study aims at comparing hemodynamic effects of pulsatile versus non-pulsatile perfusion using MEDOS DeltaStream- DP3 centrifugal pump in patients over 75 years old. Methods: Forty patients with severe aortic stenosis (mean age 80.7±3.3, mean EuroScore 5.8±1.4) undergoing AVR from 1.01.2010 to 31.01.2010 were prospectively randomized into pulsatile (n=20pts) and non-pulsatile groups (n=20pts). Pressure and flow curves were recorded simultaneously from external flow-meters (TransonicHT110) and pressure monitor at 6 time points during CPB (at pre-oxygenator, post-oxygenator, aortic cannula and patients radial artery levels). Pulsatility was quantified in terms of Energy Equivalent Pressure(EEP) and Surplus Hemodynamic Energy(SHE). Hemodynamic indexes and clinical effects were monitored during 24 hours peri-operatively. Results: Groups showed no difference in mean CPB time (p=0.98), cross-clamp time (p=0.95), mean perfusion flow (p=0.32) and pressure (p=0.16) values. In both groups the measured blood flow corresponded to the calculated one. Mean SHE generated at the outlet of the pump was 113.5±21.8 ergs/cm3 with further progressive drop along the circuit until 5.3+1.9 ergs/cm3 calculated in the patient (4.7% from initial level). The pulsatile group showed lower vascular resistance during CPB (p=0.035) and significant difference in SVR (p=0.04) and PVR (p=0.02) just after operation. Levels of SHE delivered to the patient correlated positively with urine output during CPB (R=0.34, p=0.041) and PVR after CPB (R=0.44, p=0.015). No differences between groups were found in pharmacologic support, transfusion rates, creatinine levels, respiratory indexes and intubation time. Longer ICU and hospital stay were related to severity of preoperative co-morbidities. Conclusions: Pulsatile flow produced by MEDOS DeltaStream-DP3 centrifugal pump results in hemodynamic advantages and better tissue perfusion in highrisk patients

Efficacy of Pulsatile Flow Perfusion in Adult Cardiac Surgery: Hemodynamic Energy and Vascular Reactivity

Background: The role of pulsatile (PP) versus non-pulsatile (NP) flow during a cardiopulmonary bypass (CPB) is still debated. This study's aim was to analyze hemodynamic effects, endothelial reactivity and erythrocytes response during a CPB with PP or NP. Methods: Fifty-two patients undergoing an aortic valve replacement were prospectively randomized for surgery with either PP or NP flow. Pulsatility was evaluated in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). Systemic (SVRi) and pulmonary (PVRi) vascular resistances, endothelial markers levels and erythrocyte nitric-oxide synthase (eNOS) activity were collected at different perioperative time-points. Results: In the PP group, the resultant EEP was 7.3% higher than the mean arterial pressure (MAP), which corresponded to 5150 +/- 2291 ergs/cm(3) of SHE. In the NP group, the EEP and MAP were equal; no SHE was produced. The PP group showed lower SVRi during clamp-time (p = 0.06) and lower PVRi after protamine administration and during first postoperative hours (p = 0.02). Lower SVRi required a higher dosage of norepinephrine in the PP group (p = 0.02). Erythrocyte eNOS activity results were higher in the PP patients (p = 0.04). Renal function was better preserved in the PP group (p = 0.001), whereas other perioperative variables were comparable between the groups. Conclusions: A PP flow during a CPB results in significantly lower SVRi, PVRi and increased eNOS production. The clinical impact of increased perioperative vasopressor requirements in the PP group deserves further evaluation

Increased expression of adenosine triphosphate-sensitive K+ channels in mitral dysfunction: mechanically stimulated transcription and hypoxia-induced protein stability?

The aim of this study was to test whether adenosine triphosphate-sensitive K(+) (KATP) channel expression relates to mechanical and hypoxic stress within the left human heart