Objectives This study evaluated the capacity of ultrasound-targeted microbubble destruction (UTMD) to deliver angiogenic genes, improve perfusion, and recruit progenitor cells after a myocardial ...infarction (MI) in mice. Background Angiogenic gene therapy after an MI may become a clinically relevant approach to improve the engraftment of implanted cells if targeted delivery can be accomplished noninvasively. The UTMD technique uses myocardial contrast echocardiography to target plasmid gene delivery to the myocardium and features low toxicity, limited immunogenicity, and the potential for repeated application. Methods Empty plasmids (control group) or those containing genes for vascular endothelial growth factor (VEGF), stem cell factor (SCF), or green fluorescent protein (to visualize gene delivery) were incubated with perflutren lipid microbubbles. The microbubble-deoxyribonucleic acid mixture was injected intravenously into C57BL/6 mice at 7 days after coronary artery ligation (MI). The UTMD technique facilitated transgene release into the myocardium. Twenty-one days after MI, myocardial perfusion and function were assessed by contrast echocardiography. Protein expression was quantified by Western blot and enzyme-linked immunosorbent assay. Flow cytometry quantified progenitor cell recruitment to the heart. Blood vessel density was evaluated immunohistochemically. Results Green fluorescent protein expression in the infarcted myocardium demonstrated gene delivery. Myocardial VEGF and SCF levels increased significantly in the respective groups (p < 0.05). The physiologic impact of VEGF and SCF gene delivery was confirmed by increased myocardial recruitment of VEGF receptor 2– and SCF receptor (c-kit)–expressing cells, respectively (p < 0.05). Consequently, capillary and arteriolar density (Factor VIII and alpha-smooth muscle actin staining), myocardial perfusion, and cardiac function were all enhanced (p < 0.01 relative to control group) in recipients of VEGF or SCF. Conclusions Noninvasive UTMD successfully delivered VEGF and SCF genes into the infarcted heart, increased vascular density, and improved myocardial perfusion and ventricular function. The UTMD technique may be an ideal method for noninvasive, repeated gene delivery after an MI.
Objectives Cell therapy improved cardiac function after a myocardial infarction in several preclinical studies; however, the functional benefits were limited in the initial clinical trials, perhaps ...because of inadequate cell engraftment. We used noninvasive molecular imaging to compare the distribution and myocardial retention of cells implanted by using clinical delivery routes. Methods Bone marrow stromal cells isolated from male rats and transfected with a firefly luciferase reporter gene were injected by using 3 increasingly invasive techniques (ie, intravenous, intra-aortic, and intramyocardial) into female rats 3 or 28 days after coronary ligation. Whole-body bioluminescence imaging was performed 2, 24, and 48 hours later; implanted cells were quantified at 48 hours in explanted organs by means of bioluminescence and real-time polymerase chain reaction. Results Variations in cell distribution among groups were profound, with nearly complete trapping of the injected cells in the lungs after intravenous delivery. Cell delivery into the aortic root (with the distal aorta occluded) produced minimal cell retention in the heart. Direct intramyocardial injection facilitated the best early targeting of the cells ( P < .05 vs intravenous and intra-aortic injection). Rapid signal loss over 48 hours indicated very poor cell survival in all 3 groups, although implanted cell retention was greater in mature compared with acute infarcts. Conclusions This is the first study to correlate live cell imaging with quantitative genetic and histologic techniques. Noninvasive molecular imaging tracked delivered cells and will permit the evaluation of new and improved delivery platforms designed to increase cell homing, retention, and engraftment.
Abstract Objectives The IMPACT-CABG trial is the first North American multicenter phase II randomized study of intramyocardial delivery of autologous CD133+ stem cells in patients with chronic ...ischemic cardiomyopathy undergoing coronary artery bypass grafting. The primary objective was to demonstrate safety, including freedom from major adverse cardiac events. The secondary objective was to evaluate feasibility of same-day autologous cell preparation. Although the trial was not powered to evaluate LV function, exploratory data were collected. Methods After 7 open-label patients who received cells, patients randomly received stem cells or placebo (N = 40 total, 20 per center). After completion of coronary anastomoses, up to 10 million CD133+ , CD34+ , CD45+ triple-positive cells or placebo were injected into the infarct and border zones. Patients were followed up clinically and underwent magnetic resonance imaging preoperatively and after 6 months. Results There were no procedural complications from bone marrow isolation and cell injection, no in-hospital mortality, and no protocol-related complications. Four patients had transient renal insufficiency, with 1 death during 6-month follow-up. Magnetic resonance imaging revealed that left ventricular volumes and ejection fractions improved in all patients (no difference between groups). Conclusions The trial successfully met both primary and secondary objectives, demonstrating that same-day isolation and autologous CD133+ cell delivery with coronary artery bypass grafting is safe and feasible. The positive findings support a larger randomized, multicenter trial, with higher numbers of transplanted cells to demonstrate beneficial effects. The upcoming IMPACT-CABG II trial will evaluate higher cell doses and pharmacologic enhancement to determine whether these cells improve perfusion and myocardial function.
Objective Cell therapy has received much attention for its potential to regenerate ischemic organs, but initial clinical trials in aged patients did not replicate the dramatic benefits recorded in ...preclinical studies with young animals. This study was designed to improve our understanding of age-related changes in the response to ischemic injury and the regenerative capacity of implanted cells in the context of cell therapy for older recipients. Methods and Results Restoration of regional perfusion after hind limb femoral artery ligation was impaired ( P < .05) in old (vs young) rats, reflecting approximately 50% reductions in circulating endothelial progenitor cells and the release of vascular endothelial growth factor/basic fibroblast growth factor. Bone marrow stromal cells from young or old donors implanted into the ischemic hind limbs of young or old rats restored regional perfusion. Specifically, we documented significantly greater ( P < .05) angiogenic potential in young (vs old) donor cells when recipient age was controlled and greater ( P < .05) regenerative responses in young (vs old) recipients when donor cell age was controlled. Contributing to these differences were significantly greater survival in young (vs old) donor cells (in vitro and after implantation) and about 2-fold more production of vascular endothelial growth factor/basic fibroblast growth factor and mobilization of endogenous endothelial progenitor cells in young (vs old) rats in response to ischemia. Conclusions The outcome of cell therapy in older recipients is determined by a combination of age effects on the donor cells and on the recipients' endogenous responses. Donor cell age and recipient age are equally important contributors to the outcome of cell therapy; thus, novel biointerventions will need to target both components of the process.
Objective Cell-based gene therapy can enhance the effects of cell transplantation by temporally and spatially regulating the release of the gene product. The purpose of this study was to evaluate ...transient matrix metalloproteinase inhibition by implanting cells genetically modified to overexpress a natural tissue inhibitor of matrix metalloproteinases (tissue inhibitor of matrix metalloproteinase-3) into the hearts of mutant (tissue inhibitor of matrix metalloproteinase-3–deficient) mice that exhibit an exaggerated response to myocardial infarction. Following a myocardial infarction, tissue inhibitor of matrix metalloproteinase-3–deficient mice undergo accelerated cardiac dilatation and matrix disruption due to uninhibited matrix metalloproteinase activity. This preliminary proof of concept study assessed the potential for cell-based gene therapy to reduce matrix remodeling in the remote myocardium and facilitate functional recovery. Methods Anesthetized tissue inhibitor of matrix metalloproteinase-3–deficient mice were subjected to coronary ligation followed by intramyocardial injection of vector-transfected bone marrow stromal cells, bone marrow stromal cells overexpressing tissue inhibitor of matrix metalloproteinase-3, or medium. Functional, morphologic, histologic, and biochemical studies were performed 0, 3, 7, and 28 days later. Results Bone marrow stromal cells and bone marrow stromal cells overexpressing tissue inhibitor of matrix metalloproteinase-3 significantly decreased scar expansion and ventricular dilatation 28 days after coronary ligation and increased regional capillary density to day 7. Only bone marrow stromal cells overexpressing tissue inhibitor of matrix metalloproteinase-3 reduced early matrix metalloproteinase activities and tumor necrosis factor α levels relative to medium injection. Bone marrow stromal cells overexpressing tissue inhibitor of matrix metalloproteinase-3 were also more effective than bone marrow stromal cells in preventing progressive cardiac dysfunction, preserving remote myocardial collagen content and structure, and reducing border zone apoptosis for at least 28 days after implantation. Conclusions Tissue inhibitor of matrix metalloproteinase-3 overexpression enhanced the effects of bone marrow stromal cells transplanted early after a myocardial infarction in tissue inhibitor of matrix metalloproteinase-3–deficient mice by contributing regulated matrix metalloproteinase inhibition to preserve matrix collagen and improve functional recovery.
Background The purpose of this article was to investigate bacterial biofilm formed on endoscopes and to explore the possible correlation between endoscope reprocessing procedures and bacterial ...biofilm growth on endoscope channels. Methods Sixty-six endoscope suction and biopsy channels and 13 water and air channels were collected from 66 hospitals throughout China. Scanning electron microscopy was used to observe biofilm growth on the internal surface of these channels. Questionnaires were mailed to 66 endoscopy centers to investigate reprocessing procedures for endoscopes. Results Obvious biofilm growth was detected on 36 suction and biopsy channels (36/66, 54.6%) and 10 water and air channels (10/13, 76.9%). The percentage of manual cleaning in group B (n = 36, without detection of biofilms) was 92.3% (33/36), whereas it was 50.0% (15/30) in group A (n = 30, with detection of biofilms). Follow-up of group A (n = 30) showed that no biofilm was detected, whereas biofilm was detected in group B. The difference was statistically significant ( P = .001). The proportion of detergent reuse in group B was 92.3% (33/36), and it was 61.5% in group A (18/30) ( P = .005). The proportion of alcohol-air drying in group B was 38.9% (14/36), and it was 76.7% (23/30) in group A ( P = .002). Conclusion The formation of endoscopic biofilm during clinical practice may be related to reuse of detergent, manual cleaning, and incomplete drying.
Abstract Background Clinically, hepatectomy is a clean procedure performed without routine antimicrobial prophylaxis, regardless of the extent of liver loss. Translocation of endotoxin has been ...recognized as a fatal complication leading to liver failure. After extended hepatectomy, the portal hypertension, mucosal damage, intrahepatic bile acid retention, inhibited enterokinesia, and so forth are likely to contribute to enhanced endotoxin absorption. The effect of selective bowel decontamination (SBD) on the prognosis of hepatectomy were investigated. Methods We adopted rat models of partial hepatectomy (70%, PHx) and subtotal hepatectomy (90%, SHx), gentamicin or saline of the same amount was administrated preoperatively. Liver damage makers, portal and systemic lipopolysaccharide, mucosal damage, signaling pathways, liver regeneration, and bile canalicular networks reconstruction were investigated. Results We found that SHx but not PHx resulted in significantly enhanced portal and systemic endotoxin. Inhibition of gastrointestinal gram-negative bacteria by gentamicin significantly reduced lipopolysaccharide levels and improved survival after SHx (56% with gentamicin, 24% with saline, P < 0.05). We also found SBD with gentamicin protected intestinal mucosa barrier, alleviated liver parenchymal damage, and promoted liver regeneration and bile canalicular networks reconstruction after extended liver resection. Conlusions We conclude that SBD is beneficial and necessary for extended hepatectomy.
Objectives This study investigated whether cytokine enhancement of a biodegradable patch could restore cardiac function after surgical ventricular restoration (SVR) even when seeded with cells from ...old donors. Background SVR can partially restore heart size and improve function late after an extensive anterior myocardial infarction. However, 2 limitations include the stiff synthetic patch used and the limited healing of the infarct scar in aged patients. Methods We covalently immobilized 2 proangiogenic cytokines (vascular endothelial growth factor and basic fibroblast growth factor) onto porous collagen scaffolds. We seeded human mesenchymal stromal cells from young (50.0 ± 8.0 years, N = 4) or old (74.5 ± 7.4 years, N = 4) donors into the scaffolds, with or without growth factors. The patches were characterized and used for SVR in a rat model of myocardial infarction. Cardiac function was assessed. Results In vitro results showed that cells from old donors grew slower in the scaffolds. However, the presence of cytokines modulated the aging-related p16 gene and enhanced cell proliferation, converting the old cell phenotype to a young phenotype. In vivo studies showed that 28 days after SVR, patches seeded with cells from old donors did not induce functional recovery as well as patches seeded with young cells. However, cytokine-enhanced patches seeded with old cells exhibited preserved patch area, prolonged cell survival, and augmented angiogenesis, and rats implanted with these patches had better cardiac function. The patch became an elastic tissue, and the old cells were rejuvenated. Conclusions This sustained-release, cytokine-conjugated system provides a promising platform for engineering myocardial tissue for aged patients with heart failure.
This study aimed to assess whether synergism could be achieved when combining midkine (MK) antisense oligodeoxynucleotides (anti-MK ODN) and recombinant human hepatocyte growth factor (HGF) in ...diabetic nephropathy (DN) rat models.
Rats were randomized into 6 groups: control, DN rats without treatment, DN rats treated with scrambled ODN, DN rats treated with anti-MK ODN, DN rats treated with HGF and DN rats treated with anti-MK ODN plus HGF. DN models were created by intraperitoneal injection of streptozotocin. Two weeks later, treatments commenced. ODN (1 mg/kg) was intravenously injected weekly for 4 weeks. HGF (500 μg/kg) was subcutaneously injected daily for 4 weeks. Eight weeks later, rats were euthanized. Serum and urine parameters, kidney histopathological injury scores, immunohistochemistry and protein expressions were measured.
Blood glucose, creatinine, blood urea nitrogen and urine albumin were significantly elevated in DN rats. Any single treatment markedly reduced their levels, yet combined treatment decreased them significantly further. Any monotherapy could decrease renal injury score and immunohistochemistry positive percentage, although the most prominent change was displayed in combinational therapy. Western blot showed the expression of MK was significantly elevated in DN rats. Anti-MK ODN suppressed MK significantly. The protein expressions and serum concentrations of transforming growth factor-β1 and connective tissue growth factor between monotherapy and the combined therapy were significant.
This study demonstrated that combining MK gene suppressing ODN and HGF protein synergistically attenuates renal injury in DN rats. This study may provide a novel avenue for designing future therapeutic regimens against DN.
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