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Background: Pulsatile extracorporeal circulation (ECC) may improve perfusion of critical organs during cardiac surgery. This study analyzed the influence of the components of a minimal invasive ECC (MiECC) on the transfer of pulsatile energy into the pseudo‐patient of a mock circulation. Methods: An aortic model with human‐like geometry and compliance was perfused by a diagonal pump. Surplus hemodynamic energy (SHE) was determined from flow and pressure data. Five adult‐size oxygenator models and three sizes of cannulas were compared. Pulsatile pump settings were optimized, and parallel dual‐pump configurations were evaluated. Results: Oxygenator models showed up to twofold differences in pressure gradients and influenced SHE at flow rates up to 2.0 L min−1. Adjustments of frequency, systole duration, and rotational speed gain significantly improved SHE compared with empirical settings, with SHE above 21% of mean arterial pressure at flow rates of 1.0 L min−1 to 1.5 L min−1 and SHE above 5% at 3.5 L min−1. Small diameter cannula (15 Fr) limited SHE compared with larger cannula (21 Fr and 23 Fr). Two diagonal pumps did not provide higher SHE than a single pump, but permitted additional control over pulse pressure and SHE by varying the total fraction of pulsatile flow and the fraction of flow bypassing the oxygenator. Conclusions: Proper selection of components and optimizations of pump settings significantly improved pulse pressure and SHE of pulsatile MiECC. Surplus hemodynamic energy depended on flow rate with a maximum at 1.0 L min−1–1.5 L min−1. Pulsatile MiECC may specifically assist organ perfusion during phases of low flow. [ABSTRACT FROM AUTHOR]

Background: Pulsatile perfusion during extracorporeal circulation is a promising concept to improve perfusion of critical organs. Clinical benefits are limited by the amount of pulsatile energy provided by standard pumps. The present study investigated the properties of a novel positive displacement blood pump in a mock circulation. Methods: The pump was attached to an aortic model with a human‐like geometry and compliance as a pseudo patient. Hemodynamic data were recorded while the pump settings were adjusted systematically. Results: Using a regular oxygenator, maximum flow was 2.6 L/min at a pressure of 27 mm Hg and a frequency (F) of 90 bpm. Pulse pressure (PP; 28.9 mm Hg) and surplus hemodynamic energy (SHE; 26.1% of mean arterial pressure) were highest at F = 40 bpm. Flow and pressure profiles appeared sinusoid. Using a low‐resistance membrane ventilator to assess the impact of back pressure, maximum flow was 4.0 L/min at a pressure of 58.6 mm Hg and F = 40 bpm. At F = 40 bpm, PP was 58.7 mm Hg with an SHE of 33.4%. SHE decreased with increasing flow, heart rate, and systolic percentage but surpassed 10% with reasonable settings. Conclusions: The present prototype achieved sufficient flow and pressure ranges only in the presence of a low‐resistance membrane ventilator. It delivered supraphysiologic levels of pulse pressure and SHE. Further modifications are planned to establish this concept for adult pulsatile perfusion. [ABSTRACT FROM AUTHOR]

Background and Purpose: Endocannabinoids and opioids play a vital role in mediating pain-induced analgesia. The specific effects of these compounds within the orofacial region are largely unknown. In this study, we tried to determine whether an increase in cannabinoid and opioid concentration in the CSF affects impulse transmission between the motor centres localized in the vicinity of the third and fourth cerebral ventricles.Experimental Approach: The study objectives were realized on rats using a method that allows the recording of the amplitude of evoked tongue jerks (ETJ) in response to noxious tooth pulp stimulation. The amplitude of ETJ was a measure of the effect of neurotransmitters on neural structures.Key Results: Perfusion of cerebral ventricles with anandamide (AEA), endomorphin-2 (EM-2), URB597, an inhibitor of fatty acid amide hydrolase (FAAH) and JZL195, a dual inhibitor of FAAH and monoacylglycerol lipase (MAGL) reduced the ETJ amplitude. The antinociceptive effect of AEA, EM-2, URB597 and JZL195 was blocked by CB1 receptor antagonist, AM251 and by μ receptor-antagonist, β-funaltrexamine. In contrast to AEA, 2-arachidonoylglycerol alone did not decrease ETJ amplitude.Conclusions and Implications: We demonstrated that in the orofacial area, analgesic activity is modulated by AEA and that EM-2-induced antinociception was mediated by μ and CB1 receptors. The action of AEA and EM-2 is tightly regulated by FAAH and FAAH/MAGL, by preventing the breakdown of endogenous cannabinoids in regions where they are produced on demand. Therefore, the current findings support the therapeutic potential of FAAH and FAAH/MAGL inhibitors as novel pharmacotherapeutic agents for orofacial pain. [ABSTRACT FROM AUTHOR]

Transplantation of mesenchymal stem cells (MSCs) derived from adult bone marrow has been proposed as a potential therapeutic approach for post-infarction left ventricular (LV) dysfunction. However, age-related functional decline of stem cells has restricted their clinical benefits after transplantation into the infarcted myocardium. The limitations imposed on patient cells could be addressed by genetic modification of stem cells. This study was designed to improve our understanding of genetic modification of human bone marrow derived mesenchymal stem cells (hMSCs) by polyethylenimine (PEI, branched with Mw 25 kD), one of non-viral vectors that show promise in stem cell genetic modification, in the context of cardiac regeneration for patients. We optimized the PEI-mediated reporter gene transfection into hMSCs, evaluated whether transfection efficiency is associated with gender or age of the cell donors, analysed the influence of cell cycle on transfection and investigated the transfer of therapeutic vascular endothelial growth factor gene (VEGF). hMSCs were isolated from patients with cardiovascular disease aged from 41 to 85 years. Optimization of gene delivery to hMSCs was carried out based on the particle size of the PEI/DNA complexes, N/P ratio of complexes, DNA dosage and cell viability. The highest efficiency with the cell viability near 60% was achieved at N/P ratio 2 and 6.0 μg DNA/cm2. The average transfection efficiency for all tested samples, middle-age group (<65 years), old-age group (>65 years), female group and male group was 4.32%, 3.85%, 4.52%, 4.14% and 4.38%, respectively. The transfection efficiency did not show any correlation either with the age or the gender of the donors. Statistically, there were two subpopulations in the donors; and transfection efficiency in each subpopulation was linearly related to the cell percentage in S phase. No significant phenotypic differences were observed between these two subpopulations. Furthermore, PEI-mediated therapeutic gene VEGF transfer could significantly enhance the expression level. [ABSTRACT FROM AUTHOR]

Matrigel promotes angiogenesis in the myocardium from ischemic injury and prevents remodelling of the left ventricle. We assessed the therapeutic efficacy of intracardiac matrigel injection and matrigel-mediated stem cell homing in a rat myocardial infarction (MI) model. Following MI, matrigel (250 μl) or phosphate-buffered solution (PBS) was delivered by intracardiac injection. Compared to the MI control group (MI-PBS), matrigel significantly improved left ventricular function ( n= 11, P < 0.05) assessed by pressure-volume loops after 4 weeks. There is no significant difference in infarct size between MI-matrigel (MI-M; 21.48 ± 1.49%, n= 10) and MI-PBS hearts (20.98 ± 1.25%, n= 10). The infarct wall thickness of left ventricle is significantly higher ( P < 0.01) in MI-M (0.72 ± 0.02 mm, n= 10) compared with MI-PBS (0.62 ± 0.02 mm, n= 10). MI-M hearts exhibited higher capillary density (border 130.8 ± 4.7 versus 115.4 ± 6.0, P < 0.05; vessels per high-power field [HPF; 400×], n= 6) than MI-PBS hearts. c-Kit stem cells (38.3 ± 5.3 versus 25.7 ± 1.5 c-Kit cells per HPF [630×], n= 5, P < 0.05) and CD34 cells (13.0 ± 1.51 versus 5.6 ± 0.68 CD34 cells per HPF [630×], n= 5, P < 0.01) were significantly more numerous in MI-M than in MI-PBS in the infarcted hearts ( n= 5, P < 0.05). Intracardiac matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34 and c-Kit stem cells. [ABSTRACT FROM AUTHOR]

Stromal cell-derived factor-1α (SDF-1α) mediated mobilization and homing of stem cells showed promising potential in stem cell based tissue engineering and regenerative medicine. However local and sustained release of SDF-1α is indispensable for stem cell mediated regenerative process due to its short half-life under inflammatory conditions. In this study, a gene activated collagen substrate (GAC) was formed via assembly of plasmid encoding SDF-1α into a collagen substrate to create a microenvironment favoring stem cell homing. Local release of SDF-1α from the transfected cells on GAC and its effect on CD117+ stem cell homing were investigated. Non-viral poly-ethyleneimine (25kDa PEI)/DNA complexes were mixed with rat tail collagen solution to form the GAC. Optimization of GAC was carried out based on collagen effects on the PEI/DNA complexes, viability and luciferase expression of COS7 cells on GAC. CD117+ stem cells homing in response to SDF-1α local expression from transfected cells on GAC were investigated in a flow chamber in vitro and in a mouse hind limb model in vivo. The gene expression, migration of CD117+ stem cells and the induced inflammation were investigated with immunostaining, reverse transcription polymerase chain reaction (RT-PCR) and H&E staining. The optimized parameters for GAC were DNA dosage 10 μg/cm2, molar ratio of PEI nitrogen in primary amine to DNA phosphate (N/P ratio) 4 and mass ratio of collagen to DNA (C/D ratio) 1.0. It kept cell viability above 75% and transfection efficiency around 5.8 × 105 RLU/mg protein. GAC allowed the sustained gene release up to 60 days. GAC mediated SDF-1α gene release induced migration and homing of CD117+ stem cells in vitro and in vivo significantly, and the inflammation of GAC reduced significantly two weeks after transplantation. GAC is a promising stem cell based therapeutic strategy for regenerative medicine. [ABSTRACT FROM AUTHOR]

Although studies in vivo revealed promising results in bone regeneration after implantation of scaffolds together with osteogenic progenitor cells, basic questions remain how material surfaces control the biology of mesenchymal stem cells (MSC).We used human MSC derived from bone marrow and studied the osteogenic differentiation on calcium phosphate surfaces. In osteogenic differentiation medium MSC differentiated to osteoblasts on hydroxyapatite and BONITmatrix®, a degradable xerogel composite, within 14 days. Cells revealed a higher alkaline phosphatase (ALP) activity and increased RNA expression of collagen I and osteocalcin using real-time RTPCR compared with cells on tissue culture plastic. To test whether material surface characteristics alone are able to stimulate osteogenic differentiation, MSC were cultured on the materials in expansion medium without soluble additives for osteogenic differentiation. Indeed, cells on calcium phosphate without osteogenic differentiation additives developed to osteoblasts as shown by increased ALP activity and expression of osteogenic genes, which was not the case on tissue culture plastic. Because we reasoned that the stimulating effect on osteogenesis by calcium phosphate surfaces depends on an altered cell-extracellular matrix interaction we studied the dynamic behaviour of focal adhesions using cells transfected with GFP labelled vinculin. On BONITmatrix®, an increased mobility of focal adhesions was observed compared with cells on tissue culture plastic. In conclusion, calcium phosphate surfaces are able to drive MSC to osteoblasts in the absence of osteogenic differentiation supplements in the medium. An altered dynamic behaviour of focal adhesions on calcium phosphate surfaces might be involved in the molecular mechanisms which promote osteogenic differentiation. [ABSTRACT FROM AUTHOR]

It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood–material and blood–air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC-system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004. A control group consisted of 485 patients (group 2) undergoing elective CABG in the same period using a conventional ECC and cold crystalloid cardioplegia. There were no significant differences between the two groups in terms of the duration of intubation following surgery, the length of intensive care unit-stay and the total hospital stay. Although the 30-day mortality was similar between the two groups, the incidence of postoperative complications and the perioperative use of blood products were significantly higher in the control group compared to the MECC group. The MECC System may serve as an alternative and less invasive approach to conventional ECC. [ABSTRACT FROM AUTHOR]

AF is the most common arrhythmia following open heart surgery. Transthoracic cardioversion is used when pharmacological treatment fails to restore SH, or is ineffective in controlling ventricular response rate. We report on the performance of temporary atrial defibrillation wire electrodes implanted on the epicardium of patients undergoing open heart surgery. Epicardial stainless steel wire electrodes for both pacing/sensing and atrial defibrillation were placed at the left and right atrium during open heart surgery in 100 consecutive patients (age 65 ± 9 years; male/female 77/23). Electrophysiological studies performed postoperatively revealed a test shock (0.3 J) impedance of 96 ± 12 Ω (monophasic) and 97 ± 13 Ω (biphasic). AF was induced by burst stimulation in 84 patients. All patients were successfully converted to SR. The mean energy of successful shocks was 3.1 ± 1.9 J. Atrial pacing and sensing were accomplished in all patients. Pacing threshold was 1.9 ± 1.7 V (0.5 ms) in the left atrium and 2.1 ± 2 V in the right atrium. P wave sensing was 2.5 ± 1.6 mV in the left atrium and 2.3 ± 1.4 mV in the right atrium. No complications were observed with shock application, nor with lead extraction. Atrial defibrillation using temporary epicardial wire electrodes can be performed successfully and safely in patients following cardiac operations. The shock energy required to restore SR is low. Electrical cardioversion in the absence of anesthesia should be feasible. [ABSTRACT FROM AUTHOR]

As intracardiac signal amplitudes fluctuate due to patient activity, drug intake, and other factors, it is imperative that an adequate sensing safety margin in an implanted pacemaker be used to compensate. We studied an investigational autosensing feature that automatically adjusts the device's sensitivity. Data were collected from 55 patients, with Intermedics model 292-03 or 294-03 .pacemakers, upon inclusion of the study (Visit 1); 1 month postinclusion (Visit 2); I month, 1 day postinclusion (Visit 3); then 1 month, 2 days postinclusion (Visit 4). Atrial (N = 45) and/or ventricular (N = 54) thresholds were assessed at each visit; during Visit 2, myopotential tests were performed at two sensitivity settings. Autosensing was activated following Visit 1, then programmed on randomly at Visit 2 or Visit 3. From Visit 2- Visit 4, patients were monitored during daily activities (D), exercise (E), and sleep (S) th 24-hour Halter. With Autosensing on, atrial undersensing episodes were D = 33 (p > 0.2), and S = 28 (p < 0.05); ventricular undersensing episodes were D = 6 (p > 0.5). Ventricular oversensing episodes were S = 2; atrial oversensing episodes were S = 34 (p > 0.5), D = 2, and E = 3. Comparing Autosensing adjusted sensitivity with the recommended 2:1 safety margin, 4 patients (p = 0.15) experienced atrial myopotential oversensing, and 2 patients (p = 0.15) ventricular. No unanticipated clinical events occurred. Compared with the recommended 2:1 sensing safety margin, the Autosensing feature performed equal to manual programming in preventing episodes of under/oversensing, and was better for atrial undersensing during sleep. Autosensing obviates the need for periodic reprogramming of a fixed sensitivity value. [ABSTRACT FROM AUTHOR]

Malposition of a cardiac pacemaker lead within the left ventricle represents a source of early and late thromboembolic complications. We report a case of cerebral embolism, caused by an inadvertently misplaced left ventricular electrode, occurring 3 years after implantation. The lead was removed via a transaortic approach with extracorporeal circulation. [ABSTRACT FROM AUTHOR]

Stromal cell-derived factor-1alpha (SDF-1alpha) mediated mobilization and homing of stem cells showed promising potential in stem cell based tissue engineering and regenerative medicine. However local and sustained release of SDF-1alpha is indispensable for stem cell mediated regenerative process due to its short half-life under inflammatory conditions. In this study, a gene activated collagen substrate (GAC) was formed via assembly of plasmid encoding SDF-1alpha into a collagen substrate to create a microenvironment favoring stem cell homing. Local release of SDF-1alpha from the transfected cells on GAC and its effect on CD117(+) stem cell homing were investigated. Non-viral poly-ethyleneimine (25kDa PEI)/DNA complexes were mixed with rat tail collagen solution to form the GAC. Optimization of GAC was carried out based on collagen effects on the PEI/DNA complexes, viability and luciferase expression of COS7 cells on GAC. CD117(+) stem cells homing in response to SDF-1alpha local expression from transfected cells on GAC were investigated in a flow chamber in vitro and in a mouse hind limb model in vivo. The gene expression, migration of CD117(+) stem cells and the induced inflammation were investigated with immunostaining, reverse transcription polymerase chain reaction (RT-PCR) and H&E staining. The optimized parameters for GAC were DNA dosage 10 microg/cm(2), molar ratio of PEI nitrogen in primary amine to DNA phosphate (N/P ratio) 4 and mass ratio of collagen to DNA (C/D ratio) 1.0. It kept cell viability above 75% and transfection efficiency around 5.8 x 10(5) RLU/mg protein. GAC allowed the sustained gene release up to 60 days. GAC mediated SDF-1alpha gene release induced migration and homing of CD117(+) stem cells in vitro and in vivo significantly, and the inflammation of GAC reduced significantly two weeks after transplantation. GAC is a promising stem cell based therapeutic strategy for regenerative medicine.