Prognosis of Patients With Heart Failure Receiving Autologous Myoblast Patches　- Comparison of Single-Arm Trial Data to Registry Data.

BACKGROUND: Clinical studies in regenerative medicine remain insufficient in Japan due to ethical concerns regarding the control group and a lack of statistical methodology to evaluate efficacy in a small treatment group. This study evaluated the efficacy of autologous myoblast patch (AMP) treatment for heart failure using restricted mean survival time (RMST) analysis by comparing data from a small single-arm trial to epidemiological data from a registry.Methods and Results: The clinical trial arm included 55 patients with advanced ischemic cardiomyopathy who received an AMP between 2010 and 2020. The registry-based control group comprised 937 participants with severely impaired left ventricular function who were hospitalized for heart failure during the study period. Due to the limited number of patients, RMST analysis was used to compare survival between the 2 groups. Cox regression analyses revealed non-significant differences in survival between the groups at 3, 3.5, and 4 years. In contrast, RMST analyses revealed significant differences in survival at 3 years (P=0.008) and 3.5 (P=0.024) years, but not at 4 years. CONCLUSIONS: This small single-arm trial using RMST analyses was able to detect the efficacy of AMP transplantation for advanced heart failure (compared with a registry-based control group), with better survival until 3.5 years. This approach may be useful for efficacy analyses in regenerative medicine, where traditional clinical trials are difficult.

New regional drug delivery system by direct epicardial placement of slow-release prostacyclin agonist promise therapeutic angiogenesis in a porcine chronic myocardial infarction.

Although prostacyclin is an endogenous factor for the protection and regeneration of damaged tissue, the use of clinically available prostacyclin analogues for treating chronic pathological conditions is limited owing to their short half-lives. A new reagent, ONO-1301SR, which is a unique synthetic prostacyclin agonist polymerized with lactic and glycolic acid, has been demonstrated to constitutively release prostacyclin analogues to adjacent tissues, suggesting its therapeutic potential via slow-release delivery into a specific organ. In this study, we investigated the regenerative effect of direct epicardial delivery of the ONO-1301SR on a heart with a chronic myocardial infarct. An ameroid constrictor was placed on the left anterior descending coronary artery of Göttingen minipigs for 4 weeks to induce ischemic cardiomyopathy; this was followed by direct epicardial placement of ONO-1301SR-immersed gelatinous sheet, or only a gelatinous sheet on the anterolateral surface of the heart. Epicardial placement of ONO-1301SR resulted in significant recovery of global cardiac functions and regional wall motion of the lateral wall. Importantly, after epicardial placement of ONO-1301SR for 4 weeks, the myocardial blood flow significantly increased in the lateral region as assessed by 13N-ammonia positron emission tomography; this finding was consistent with significantly increased capillary density in the peri-infarct area with up-regulated angiogenic cytokine expression. Conclusion: Use of the slow-release drug delivery system of prostacyclin agonist yielded regenerative angiogenesis, including increased regional blood perfusion and systolic function in a porcine model of chronic myocardial infarction.

Targeted delivery of adipocytokines into the heart by induced adipocyte cell-sheet transplantation yields immune tolerance and functional recovery in autoimmune-associated myocarditis in rats.

BACKGROUND: Clinical prognosis is critically poor in fulminant myocarditis, while it's initiation or progression is fated, in part, by T cell-mediated autoimmunity. Adiponectin (APN) and associated adipokines were shown to be immune tolerance inducers, although the clinically relevant delivery method into target pathologies is under debate. Whether the cell sheet-based delivery system of adipokines might induce immune tolerance and functional recovery in experimental autoimmune myocarditis (EAM) was tested. METHODS AND RESULTS: Scaffold-free-induced adipocyte cell-sheet (iACS) was generated by differentiating adipose tissue-derived syngeneic stromal vascular-fraction cells into adipocytes on temperature-responsive dishes. Rats with EAM underwent iACS implantation or sham operation. Supernatants of iACS contained a high level of APN and hepatocyte growth factor (HGF), and reduced proliferation of CD4-positive T cells in vitro. Immunohistolabelling showed that the iACS implantation elevated the levels of APN and HGF in the myocardium compared to the sham operation, which attenuated the immunological response by inhibiting CD68-positive macropharges and CD4-positive T-cells and activating Foxp3-positive regulatory T cells. Consequently, left ventricular ejection fraction was significantly greater after the iACS implantation than after the sham operation, in association with less collagen accumulation. CONCLUSIONS: The targeted delivery of adipokines using tissue-engineered iACS ameliorated cardiac performance of the EAM rat model via effector T cell suppression and induction of immune tolerance. These findings might suggest a potential of this tissue-engineered drug delivery system in treating fulminant myocarditis in the clinical setting.

Induced adipocyte cell-sheet ameliorates cardiac dysfunction in a mouse myocardial infarction model: a novel drug delivery system for heart failure.

BACKGROUND: A drug delivery system that constitutively and effectively retains cardioprotective reagents in the targeted myocardium has long been sought to treat acute myocardial infarction. We hypothesized that a scaffold-free induced adipocyte cell-sheet (iACS), transplanted on the surface of the heart, might intramyocardially secrete multiple cardioprotective factors including adiponectin (APN), consequently attenuating functional deterioration after acute myocardial infarction. METHODS AND RESULTS: Induced ACS were generated from adipose tissue-derived cells of wild-type (WT) mice (C57BL/6J), which secreted abundant APN, hepatocyte growth factor, and vascular endothelial growth factor in vitro. Transplanted iACS secreted APN into the myocardium of APN-knockout (KO) mice at 4 weeks. APN was also detected in the plasma of iACS-transplanted APN-KO mice at 3 months (245 ± 113 pg/mL). After left anterior descending artery ligation, iACS, generated from either WT (n=40) or APN-KO (n=40) mice, were grafted onto the surface of the anterior left ventricular wall of WT mice, or only left anterior descending artery ligation was performed (n=43). Two days later, inflammation and infarct size were significantly diminished only in the WT-iACS treated mice. One month later, cardiomyocyte diameter and percent fibrosis were smaller, whereas ejection fraction and survival were greater in the WT-iACS treated mice compared with the KO-iACS-treated or nontreated mice. CONCLUSIONS: Cardioprotective factors including APN, hepatocyte growth factor, and vascular endothelial growth factor were secreted from iACS. Transplantation of iACS onto the acute myocardial infarction heart attenuated infarct size, inflammation, and left ventricular remodeling, mediated by intramyocardially secreted APN in a constitutive manner. This method might be a novel drug delivery system to treat heart disease.

Downregulation of ferritin heavy chain increases labile iron pool, oxidative stress and cell death in cardiomyocytes.

Ferritin heavy chain (FHC) protein was significantly reduced in murine failing hearts following left coronary ligation or thoracic transverse aortic constriction. The mRNA expression of FHC was not significantly altered in failing hearts, compared to that in control sham-operated hearts. Prussian blue staining revealed spotty iron depositions in myocardial infarct failing hearts. Oxidative stress was enhanced in the myocardial infarct failing hearts, as evidenced by increases in 4-hydroxy-2-nonenal and 8-hydroxy-2'-deoxyguanosine immunoreactivity. To clarify the functional significance of FHC downregulation in hearts, we infected rat neonatal cardiomyocytes with adenoviral vector expressing short hairpin RNA targeted to FHC (Ad-FHC-RNAi). The downregulation of FHC induced a reduction in the viability of cardiomyocytes. The relative number of iron deposition-, 4-hydroxy-2-nonenal- or 8-hydroxy-2'-deoxyguanosine-positive cardiomyocytes was significantly higher in Ad-FHC-RNAi-infected cardiomyocytes than in control vector-infected cardiomyocytes. Treatment of Ad-FHC-RNAi-infected cardiomyocytes with desferrioxamine, an iron chelator, significantly reduced the number of iron, 4-hydroxy-2-nonenal or 8-hydroxy-2'-deoxyguanosine-positive cells, and increased viability. In addition, treatment with N-acetyl cysteine, an antioxidant, significantly reduced the number of 4-hydroxy-2-nonenal- or 8-hydroxy-2'-deoxyguanosine-positive cells. Reduced viability in Ad-FHC-RNAi-infected cardiomyocytes was significantly improved with N-acetyl cysteine treatment. These findings indicate that excessive free iron and the resultant enhanced oxidative stress caused by downregulation of FHC lead to cardiomyocyte death. The decrease in FHC expression in failing hearts may play an important role in the pathogenesis of heart failure.

Impact of synovial membrane-derived stem cell transplantation in a rat model of myocardial infarction.

To explore a new source of cell therapy for myocardial infarction (MI), we assessed the usefulness of mesenchymal stem cells derived from synovial membrane samples (SM MSCs). We developed a model of MI by ligation of the proximal left anterior descending coronary artery (LAD) in Lewis rats. Two weeks after ligation, 5 x 10(6) SM MSCs were injected into the MI scar area (T group, n = 9), while buffer was injected into the control group (C group, n = 9). Cardiac performances measured by echocardiography at 4 weeks after transplantation were significantly increased in the T group as compared with the C group. Masson's trichrome staining showed that SM MSC transplantation decreased collagen volume in the myocardium. Engrafted SM MSCs were found in the border zone of the infarct area. Immunohistological analysis showed that these cells were positive for the sarcomeric markers alpha-actinin and titin, and negative for desmin, troponin T, and connexin 43. SM MSC transplantation improved cardiac performance in a rat model of MI in the subacute phase, possibly through transdifferentiation of the engrafted cells into a myogenic lineage, which led to inhibition of myocardial fibrosis. Our results suggest that SM MSCs are a potential new regeneration therapy candidate for heart failure.

Allogenic mesenchymal stem cell transplantation has a therapeutic effect in acute myocardial infarction in rats.

The goal of the study was to examine if allogenic mesenchymal stem cell (MSC) transplantation is a useful therapy for acute myocardial infarction (AMI). Buffer (control; group C, n=41), MSCs of male ACI rats (allogenic; group A, n=38, 5 x 10(6)), or MSCs of male LEW rats (syngenic; group S, n=40, 5 x 10(6)) were injected into the scar 15 min after myocardial infarction in female LEW rats. After 28 days, fractional left ventricular shortening significantly increased in groups A (21.3+/-1.7%, P=0.0467) and S (23.2+/-1.9%, P=0.0140), compared to group C (17.1+/-0.9%). Fibrosis in groups A and S was significantly lower. Quantitative PCR of the male-specific sry gene showed disappearance of donor cells within 28 days (5195+/-1975 cells). Secretion of vascular endothelial growth factor (VEGF) by MSCs was enhanced under hypoxic conditions in vitro. In groups A and S, the plasma VEGF concentration, VEGF level, and capillary density in recipient hearts increased after 28 days. Flow cytometry revealed the absence of B7 signal molecules on MSCs. A mixed lymphocyte reaction showed that ACI MSCs failed to stimulate proliferation of LEW lymphocytes. After 1 day after cell transplantation, transient increases in interleukin-1 beta and monocyte chemoattractant protein-1 in recipient hearts were enhanced in group A, with macrophage infiltration at the injection site. T cells remained at the level of normal tissue in all groups. We conclude that allogenic MSC transplantation therapy is useful for AMI. The donor MSCs disappear rapidly, but become a trigger of VEGF paracrine effect, without induction of immune rejection.

Building A New Treatment For Heart Failure-Transplantation of Induced Pluripotent Stem Cell-derived Cells into the Heart.

Advanced cardiac failure is a progressive intractable disease and is the main cause of mortality and morbidity worldwide. Since this pathology is represented by a definite decrease in cardiomyocyte number, supplementation of functional cardiomyocytes into the heart would hypothetically be an ideal therapeutic option. Recently, unlimited in vitro production of human functional cardiomyocytes was established by using induced pluripotent stem cell (iPSC) technology, which avoids the use of human embryos. A number of basic studies including ours have shown that transplantation of iPSCderived cardiomyocytes (iPSC-CMs) into the damaged heart leads to recovery of cardiac function, thereby establishing "proof-of-concept" of this iPSC-transplantation therapy. However, considering clinical application of this therapy, its feasibility, safety, and therapeutic efficacy need to be further investigated in the pre-clinical stage. This review summarizes up-to-date important topics related to safety and efficacy of iPSC-CMs transplantation therapy for cardiac disease and discusses the prospects for this treatment in clinical studies.

The Paracrine Effect of Skeletal Myoblasts Is Cardioprotective Against Oxidative Stress and Involves EGFR-ErbB4 Signaling, Cystathionase, and the Unfolded Protein Response.

Therapeutic effects of skeletal myoblast transplantation into the myocardium are mediated via paracrine factors. We investigated the ability of myoblast-derived soluble mediators to protect cardiomyocytes from oxidative stress. Fetal rat cardiac cells were treated with conditioned medium from cultures of myoblasts or cardiac fibroblasts, and oxidative stress was induced with H2O2. Myoblast-derived factors effectively prevented oxidative stress-induced cardiac cell death and loss of mitochondrial membrane potential. This protective effect was mediated via epidermal growth factor (EGF) receptor and c-Met signaling, and mimicked by neuregulin 1 but not EGF. Microarray analysis of cardiac cells treated with myoblast versus cardiac fibroblast-derived mediators revealed differential regulation of genes associated with antioxidative effects: cystathionine-γ-lyase (cst), xanthine oxidase, and thioredoxin-interacting protein as well as tribbles homolog 3 (trib3). Cardiac cell pretreatment with tunicamycin, an inducer of trib3, also protected them against H2O2-induced cell death. Epicardial transplantation of myoblast sheets in a rat model of acute myocardial infarction was used to evaluate the expression of CST and trib3 as markers of myoblasts' paracrine effect in vivo. Myoblast sheets induced expression of the CST as well as trib3 in infarcted myocardium. CST localized around blood vessels, suggesting smooth muscle cell localization. Our results provide a deeper molecular insight into the therapeutic mechanisms of myoblast-derived paracrine signaling in cardiac cells and suggest that myoblast transplantation therapy may prevent oxidative stress-induced cardiac deterioration and progression of heart failure.

Tissue cardiomyoplasty using bioengineered contractile cardiomyocyte sheets to repair damaged myocardium: their integration with recipient myocardium.

BACKGROUND: We hypothesized that tissue-engineered contractile cardiomyocyte sheets without a scaffold would show histological and electrical integration with impaired myocardium, leading to the regeneration of infarcted myocardium. METHODS: Neonatal rat cardiomyocytes were cultured on Poly(N-isopropylacrylamide)-grafted polystyrene dishes and detached as a square cell sheet at 20 degrees C. Two sheets were stacked to make thicker contractile cardiac sheets. In cross-section, the stacked sheets looked like homogeneous heart-like tissue. Two weeks after rats were subjected to left anterior descending (LAD) ligation, two treatments were conducted: 1) cardiomyocyte sheet implantation (T group, n=10), and 2) fibroblast sheet implantation (F group, n=10). The control group underwent no additional treatment (C group, n=10). RESULTS: Echocardiography demonstrated that cardiac performance was significantly ameliorated in the T group 2, 4, and 8 weeks after implantation. The cardiomyocyte sheets became attached to the infarcted myocardium, showed angiogenesis, expressed connexin-43, and appeared as homogeneous tissue in the myocardium Electrophysiological experiments showed a QRS complex with one peak in the treated scar area in the T group, but two peaks, indicative of branch block, in that of the other groups. Furthermore, the threshold for pacing of the recipient heart was lower in the T group than in the other groups. CONCLUSIONS: Cardiomyocyte sheets integrated with the impaired myocardium and improved cardiac performance in a model of ischemic myocardium. Techniques using such tissue-engineered cell sheets are introducing the promising concept of tissue cardiomyoplasty to the field of regenerative medicine.

Comparison of arrhythmogenicity and proinflammatory activity induced by intramyocardial or epicardial myoblast sheet delivery in a rat model of ischemic heart failure.

Although cell therapy of the failing heart by intramyocardial injections of myoblasts to results in regenerative benefit, it has also been associated with undesired and prospectively fatal arrhythmias. We hypothesized that intramyocardial injections of myoblasts could enhance inflammatory reactivity and facilitate electrical cardiac abnormalities that can be reduced by epicardial myoblast sheet delivery. In a rat model of ischemic heart failure, myoblast therapy either by intramyocardial injections or epicardial cell sheets was given 2 weeks after occlusion of the coronary artery. Ventricular premature contractions (VPCs) were assessed, using an implanted three-lead electrocardiograph at 1, 7, and 14 days after therapy, and 16-point epicardial electropotential mapping (EEPM) was used to evaluate ventricular arrhythmogenicity under isoproterenol stress. Cardiac functioning was assessed by echocardiography. Both transplantation groups showed therapeutic benefit over sham therapy. However, VPCs were more frequent in the Injection group on day 1 and day 14 after therapy than in animals receiving epicardial or sham therapy (p < 0.05 and p < 0.01, respectively). EEPM under isoproterenol stress showed macroreentry at the infarct border area, leading to ventricular tachycardias in the Injection group, but not in the myoblast sheet- or sham-treated groups (p = 0.045). Both transplantation types modified the myocardial cytokine expression profile. In animals receiving epicardial myoblast therapy, selective reductions in the expressions of interferon gamma, interleukin (IL)-1ß and IL12 were observed, accompanied by reduced infiltration of inflammatory CD11b- and CD68-positive leukocytes, compared with animals receiving myoblasts as intramyocardial injections. Intramyocardial myoblast delivery was associated with enhanced inflammatory and immunomodulatory reactivity and increased frequency of VPCs. In comparison to intramyocardial injection, the epicardial route may serve as the preferred method of skeletal myoblast transplantation to treat heart failure.

Sustained-release delivery of prostacyclin analogue enhances bone marrow-cell recruitment and yields functional benefits for acute myocardial infarction in mice.

BACKGROUND: A prostacyclin analogue, ONO-1301, is reported to upregulate beneficial proteins, including stromal cell derived factor-1 (SDF-1). We hypothesized that the sustained-release delivery of ONO-1301 would enhance SDF-1 expression in the acute myocardial infarction (MI) heart and induce bone marrow cells (BMCs) to home to the myocardium, leading to improved cardiac function in mice. METHODS AND RESULTS: ONO-1301 significantly upregulated SDF-1 secretion by fibroblasts. BMC migration was greater to ONO-1301-stimulated than unstimulated conditioned medium. This increase was diminished by treating the BMCs with a CXCR4-neutralizing antibody or CXCR4 antagonist (AMD3100). Atelocollagen sheets containing a sustained-release form of ONO-1301 (n = 33) or ONO-1301-free vehicle (n = 48) were implanted on the left ventricular (LV) anterior wall immediately after permanent left-anterior descending artery occlusion in C57BL6/N mice (male, 8-weeks-old). The SDF-1 expression in the infarct border zone was significantly elevated for 1 month in the ONO-1301-treated group. BMC accumulation in the infarcted hearts, detected by in vivo imaging after intravenous injection of labeled BMCs, was enhanced in the ONO-1301-treated hearts. This increase was inhibited by AMD3100. The accumulated BMCs differentiated into capillary structures. The survival rates and cardiac function were significantly improved in the ONO-1301-treated group (fractional area change 23±1%; n = 22) compared to the vehicle group (19±1%; n = 20; P = 0.004). LV anterior wall thinning, expansion of infarction, and fibrosis were lower in the ONO-1301-treated group. CONCLUSIONS: Sustained-release delivery of ONO-1301 promoted BMC recruitment to the acute MI heart via SDF-1/CXCR4 signaling and restored cardiac performance, suggesting a novel mechanism for ONO-1301-mediated acute-MI heart repair.

Myoblast sheet can prevent the impairment of cardiac diastolic function and late remodeling after left ventricular restoration in ischemic cardiomyopathy.

BACKGROUND: Impairment of diastolic function and late remodeling are concerns after left ventricular restoration (LVR) for ischemic cardiomyopathy. This study aims to evaluate the effects of combined surgery of myoblast sheets (MS) implantation and LVR. METHODS: Rat myocardial infarction model was established 2 weeks after left anterior descending artery ligation. They were divided into three groups: sham operation (n=15; group sham), LVR by plicating the infracted area (n=15; group LVR), and MS implantation with LVR (n=15; group LVR+MS). RESULTS: Serial echocardiographic study revealed significant LV redilatation and decrease of ejection fraction 4 weeks after LVR in group LVR. MS implantation combined with LVR prevented those later deteriorations of LV function in group LVR+MS. Four weeks after the operation, a hemodynamic assessment using a pressure-volume loop showed significantly preserved diastolic function in group LVR+MS; end-diastolic pressure (LVR vs. LVR+MS: 9.0±6.6 mm Hg vs. 2.0±1.0 mm Hg, P<0.05), end-diastolic pressure-volume relationship (LVR vs. LVR+MS 42±23 vs. 13±6, P<0.05). Histological examination revealed cellular hypertrophy and LV fibrosis were significantly less and vascular density was significantly higher in group LVR+MS than in the other two groups. Reverse transcription polymerase chain reaction demonstrated significantly suppressed expression of transforming growth factor-beta, Smad2, and reversion-inducing cysteine-rich protein with Kazal motifs in group LVR+MS. CONCLUSIONS: MS implantation decreased cardiac fibrosis by suppressing the profibrotic gene expression and attenuated the impairment of diastolic function and the late remodeling after LVR. It is suggesting that MS implantation may improve long-term outcome of LVR for ischemic heart disease.

Allogenic skeletal myoblast transplantation in acute myocardial infarction model rats.

BACKGROUND: The limitations of syngenic cell therapy include patient safety and quality control of the source cells. Therefore, it is important to develop and assess procedures using allogenic cells. We investigated the impact of allogenic skeletal myoblast (SMB) transplantation on acute myocardial infarction with respect to immune response, donor cell survival, and therapeutic efficacy. METHODS: Female Lewis rats underwent proximal left anterior descending coronary artery ligation. Fifteen minutes later, they underwent major histocompatibility (MHC)-matched Lewis SMB transplantation (group S) and MHC-mismatched ACI SMB transplantation (group A), or treated with buffer injection as a control (group C). RESULTS: Flow cytometry showed that the SMBs expressed MHC antigens and B7 signal molecules in vitro. In group A, transcription levels of interleukin-2 receptor and interferon-γ were significantly increased 7 days after transplantation, and the area surrounding the donor SMBs was intensely infiltrated with CD4- and CD8-positive cells. Estimation of the number of donor cells in the recipient left ventricular chamber revealed that except for day 0, group A had fewer donor SMBs, which disappeared faster, compared with group S. Echocardiography demonstrated that the ejection fraction (EF) of group A was lower than that of group S. CONCLUSION: MHC-mismatched allogenic SMB transplantation in infarcted myocardium induces the immune response and acceleration of donor cell clearance, decreasing the therapeutic effect. Donor cell survival and inflammation may play important roles in the therapeutic mechanism of SMB transplantation therapy for acute myocardial infarction.

Impaired myocardium regeneration with skeletal cell sheets--a preclinical trial for tissue-engineered regeneration therapy.

BACKGROUND: We hypothesized that autologous skeletal cell (SC) sheets regenerate the infract myocardium in porcine heart as a preclinical trial. METHODS AND RESULTS: The impaired heart was created by implantation of ameroid constrictor on left anterior descending for 4 weeks. SCs isolated from leg muscle were cultured and detached from the temperature-responsive domain-coated dishes as single monolayer cell sheet at 20 degrees C. The following therapies were conducted: SC sheets (SC group, n=5); sham (C group n=5). Echocardiography demonstrated that cardiac performance was significantly improved in the SC group 3 and 6 months after operation (fractional area shortening, 3 months; SC vs. C=49.5+/-2.8 vs. 24.6+/-2.0%, P<0.05) and left ventricle dilatation was well attenuated in the SC group. Color kinesis index showed that distressed regional diastolic and systolic function in infarcted anterior wall was significantly recovered (SC vs. C=57.4+/-8.6 vs. 30.2+/-4.7%, P<0.05, diastolic: 58.5+/-4.5 vs. 35.4+/-6.6%, P<0.05, systolic). Factor VIII immunostains demonstrated that vascular density was significantly higher in the SC group than the C group. And % fibrosis and cell diameter were significantly lower in the SC group. And hematoxylin-eosin staining depicted that skeletal origin cells and well-developed-layered smooth muscle cells were detected in the implanted area. Positron emission tomography showed better myocardial perfusion and more viable myocardial tissue in the distressed myocardium receiving SC sheets compared with the myocardium receiving no sheets. CONCLUSIONS: SC sheet implantation improved cardiac function by attenuating the cardiac remodeling in the porcine ischemic myocardium, suggesting a promising strategy for myocardial regeneration therapy in the impaired myocardium.

Combined strategy using myoblasts and hepatocyte growth factor in dilated cardiomyopathic hamsters.

BACKGROUND: There are few reports on treating dilated cardiomyopathy (DCM) with myoblast transplantation, and these show limited efficacy. Hepatocyte growth factor has cardioprotective effects on failed myocardium. Here, we combined these two treatments and analyzed cardiac function in DCM hamsters. METHODS: Twenty-seven-week-old BIO TO-2 hamsters, which show moderate cardiac remodeling, were divided into four treatment groups: myoblast transplantation (T group, n = 24), human hepatocyte growth factor gene transfection (H group, n = 29), combined treatment (T+H group, n = 21), and medium alone (C group, n = 26). RESULTS: Significantly better fractional shortening was observed in the T+H group compared with the others (14.9% +/- 1.0%, 11.7% +/- 1.5%, 11.3% +/- 1.3%, and 8.6% +/- 1.1 %, in the T+H, H, T, and C groups, respectively). Immunohistochemical analysis showed alpha- and beta-sarcoglycan expression in the hearts of the H and T+H groups but not in the other groups. There was less myocardial fibrosis in the H and T+H groups than in the other two, and neovascularization in the T+H group was significantly greater than in the other groups (266 +/- 24, 209 +/- 27, 199 +/- 36, and 96 +/- 17 vessels/mm2, in the T+H, H, T, and C groups, respectively). Survival was significantly prolonged in the H and T+H groups compared with the other groups. CONCLUSIONS: Hepatocyte growth factor gene transfection and myoblast transplantation preserved the cardiac function of DCM hamsters, probably through different mechanisms, and the combined treatments preserved cardiac performance better than either treatment alone. The combined therapy is a promising strategy for treating DCM.

Lung tissue engineering technique with adipose stromal cells improves surgical outcome for pulmonary emphysema.

RATIONALE AND OBJECTIVES: Hepatocyte growth factor (HGF) is a potent regenerative factor generated after a lung injury, and HGF supplementation after surgical reduction has been shown to enhance compensatory growth in remnant lungs and improve pathophysiologic conditions in a rat model of emphysema. Adipose tissue-derived stromal cells (ASCs) produce a large amount of angiogenic factors, including HGF. After lung volume reduction surgery (LVRS), we treated rats by implanting HGF-secreting ASCs with a scaffold onto the remnant lung tissue to determine the usefulness of this technique for treating respiratory dysfunction. METHODS AND MAIN RESULTS: Cells were isolated from rat inguinal adipose tissue and characterized by flow cytometry. ASCs were cultured on a polyglycolic acid felt sheet as a sealant material, and were shown to secrete significantly greater amounts of HGF than other angiogenic factors. Next, ASCs on polyglycolic acid felt sheets were used to cover the cut edge of the remaining lungs after LVRS for emphysema in rats. One week after implantation of the ASCs, both alveolar and vascular regeneration were significantly accelerated as compared with the rats that underwent LVRS alone. Consequently, gas exchange and exercise tolerance were also significantly restored, with these good results persisting for more than 1 mo. CONCLUSIONS: The present findings demonstrate the therapeutic potential of cell therapy using ASCs with a scaffold for selective delivery of HGF to remnant lungs, which resulted in enhancement of compensatory growth, after surgical resection. This approach may provide a new strategy for lung tissue engineering to improve LVRS outcome.