Modification of cardiac disease by transgenically altered histone deacetylase 6.

Histone deacetylase 6 (HDAC6) is known to deacetylate amino acid lysine in alpha-tubulin. However, the functional role of HDAC6 in the progression of cardiac disease remains uncertain. The functional role of HDAC6 in the hearts was examined using transgenic (TG) mice expressing either human wild-type HDAC6, deacetylase inactive HDAC6 (HDAC6H216A, H611A), and human HDAC6 replaced all serine or threonine residues with aspartic acid at N-terminal 1- 43 amino acids (HDAC6NT-allD) specifically in the hearts. Overexpression of wild-type HDAC6 significantly reduced acetylated tubulin levels, and overexpression of HDAC6H216A, H611A significantly increased it in the mouse hearts. Detectable acetylated tubulin disappeared in HDAC6NT-allD TG mouse hearts. Neither histological alteration nor alteration of cardiac function was observed in the HDAC6 TG mouse hearts. To analyze the role of HDAC6 and acetylated tubulin in disease conditions, we examined HDAC6 in isoprenaline-induced hypertrophy or pressure-overload hypertrophy (TAC). No obvious alteration in the heart weight/body weight ratio or gene expressions of hypertrophic markers between NTG and HDAC6NT-allD mice was observed following treatment with isoprenaline. In contrast, a marked reduction in the shortening fraction and dilated chamber dilatation was detected in the HDAC6NT-allD TG mouse hearts 2 weeks after TAC. A sustained low level of acetylated tubulin and acetylated cortactin was observed in the TAC HDAC6NT-allD TG mouse hearts. Cardiac HDAC6 activity that can regulate acetylated levels of tubulin and cortactin may be critical factors involved in cardiac disease such as pressure-overload hypertrophy.

Euphausia pacifica (North Pacific Krill): Review of Chemical Features and Potential Benefits of 8-HEPE against Metabolic Syndrome, Dyslipidemia, NAFLD, and Atherosclerosis.

Marine n-3 fatty acids are well known to have health benefits. Recently, krill oil, which contains phospholipids, has been in the spotlight as an n-3 PUFA-containing oil. Euphausia pacifica (E. pacifica), also called North Pacific krill, is a small, red crustacean similar to shrimp that flourishes in the North Pacific Ocean. E. pacifica oil contains 8-hydroxyeicosapentaenoic acid (8-HEPE) at a level more than 10 times higher than Euphausia superba oil. 8-HEPE can activate the transcription of peroxisome proliferator-activated receptor alpha (PPARα), PPARγ, and PPARδ to levels 10, 5, and 3 times greater than eicosapentaenoic acid, respectively. 8-HEPE has beneficial effects against metabolic syndrome (reduction in body weight gain, visceral fat area, amount of gonadal white adipose tissue, and gonadal adipocyte cell size), dyslipidemia (reduction in serum triacylglycerol and low-density lipoprotein cholesterol and induction of serum high-density lipoprotein cholesterol), atherosclerosis, and nonalcoholic fatty liver disease (reduction in triglyceride accumulation and hepatic steatosis in the liver) in mice. Further studies should focus on the beneficial effects of North Pacific krill oil products and 8-HEPE on human health.

Mizagliflozin, a selective SGLT1 inhibitor, improves vascular cognitive impairment in a mouse model of small vessel disease.

Previously, we showed that sodium/glucose cotransporter 1 (SGLT1) participates in vascular cognitive impairment in small vessel disease. We hypothesized that SGLT1 inhibitors can improve the small vessel disease induced-vascular cognitive impairment. We examined the effects of mizagliflozin, a selective SGLT1 inhibitor, and phlorizin, a non-selective SGLT inhibitor, on vascular cognitive impairment in a mouse model of small vessel disease. Small vessel disease was created using a mouse model of asymmetric common carotid artery surgery (ACAS). Two and/or 4 weeks after ACAS, all experiments were performed. Cerebral blood flow (CBF) was decreased in ACAS compared with sham-operated mice. Phlorizin but not mizagliflozin reversed the decreased CBF of ACAS mice. Both mizagliflozin and phlorizin reversed the ACAS-induced decrease in the latency to fall in a wire hang test of ACAS mice. Moreover, they reversed the ACAS-induced longer escape latencies in the Morris water maze test of ACAS mice. ACAS increased SGLT1 and proinflammatory cytokine gene expressions in mouse brains and phlorizin but not mizagliflozin normalized all gene expressions in ACAS mice. Hematoxylin/eosin staining demonstrated that they inhibited pyknotic cell death in the ACAS mouse hippocampus. In PC12HS cells, IL-1ß increased SGLT1 expression and decreased survival rates of cells. Both mizagliflozin and phlorizin increased the survival rates of IL-1ß-treated PC12HS cells. These results suggest that mizagliflozin and phlorizin can improve vascular cognitive impairment through the inhibition of neural SGLT1 and phlorizin also does so through the improvement of CBF in a mouse model of small vessel disease.

Chronic HDAC6 Activation Induces Atrial Fibrillation Through Atrial Electrical and Structural Remodeling in Transgenic Mice.

Atrial fibrillation (AF) is a relatively common complication of hypertension. Chronic hypertension induces cardiac HDAC6 catalytic activity. However, whether HDAC6 activation contributes to hypertension-induced AF is still uncertain. We examined whether chronic cardiac HDAC6 activation-induced atrial remodeling, leading to AF induction.The HDAC6 constitutively active transgenic (TG) (HDAC6 active TG) mouse overexpressing the active HDAC6 protein, specifically in cardiomyocytes, was created to examine the effects of chronic HDAC6 activation on atrial electrical and structural remodeling and AF induction in HDAC6 active TG and non-transgenic (NTG) mice. Left atrial burst pacing (S1S1 = 30 msec) for 15-30 sec significantly increased the frequency of sustained AF in HDAC6 active-TG mice compared with NTG mice. Left steady-state atrial pacing (S1S1 = 80 msec) decreased the atrial conduction velocity in isolated HDAC6 active TG compared with NTG mouse atria. The atrial size was similar between HDAC6 active TG and NTG mice. In contrast, atrial interstitial fibrosis increased in HDAC6 active TG compared with that of NTG mouse atria. While protein expression levels of both CX40 and CX43 were similar between HDAC6 active TG and NTG mouse atria, a heterogeneous distribution of CX40 and CX43 occurred in HDAC6 active-TG mouse atria but not in NTG mouse atria. Gene expression of interleukin 6 increased in HDAC6 active TG compared with NTG mouse atria.Chronic cardiac HDAC6 activation induced atrial electrical and structural remodeling, and sustained AF. Hypertension-induced cardiac HDAC6 catalytic activity may play important roles in the development of AF.

Expression of cell adhesion molecule, Gicerin/CD146 during the formation of heart and in the cardiac hypertrophy.

Gicerin/CD146 is a cell adhesion molecule which belongs to the immunoglobulin (Ig) superfamily. We have reported the existence of gicerin/CD146 in the nervous system, heart, lung and smooth muscles of blood vessels. In this study, we make a cardiac hypertrophy model rat by constricting the rat aorta (AAC, ascending aortic constriction) and examined the effect on the expression of gicerin/CD146 in the heart. We found that the expression level of gicerin/CD146 was increased by the AAC treatment. Next, stretch stimulation was applied to myocardial cell line H9c2 cells to confirm that gicerin/CD146 may participate in the cellular hypertrophy model. We also treated the cells with inhibitors of MAP pathway enzymes. In cultured myocardial cells, the expression level of gicerin/CD146 was increased by the stretch stimulation and decreased by inhibiting the MAP pathway. Based on the above findings, it is suggested that the expression of gicerin/CD146 is involved in cardiac hypertrophy, and that the MAP pathway may be involved in the expression of gicerin/CD146 RNA in the cardiomyocyte. In addition, the expression level of gicerin/CD146 RNA in neonatal rats was upregulated after birth. Therefore, it is suggested that gicerin/CD146 might participate in the increase of myocardial cell volume both in the pathway of cardiac hypertrophy and in the developmental growth of heart.

8-HEPE-Concentrated Materials from Pacific Krill Improve Plasma Cholesterol Levels and Hepatic Steatosis in High Cholesterol Diet-Fed Low-Density Lipoprotein (LDL) Receptor-Deficient Mice.

Eicosapentaenoic acid (EPA), one of the N-3 polyunsaturated fatty acids (n-3 PUFAs), is a major active ingredient of fish that contributes to improve dyslipidemia. Recently, we demonstrated that 8-hydroxyeicosapentaenoic acid (8-HEPE) had a more positive effect on metabolic syndrome than EPA, and that 8-HEPE induced peroxisome proliferator-activated receptor (PPAR)α activation in the liver. We investigated the effects of 8-HEPE-concentrated materials from Pacific krill on dyslipidemia and hepatic steatosis in low-density lipoprotein (LDL) receptor-deficient (LDLR-KO) mice. Eight-week-old male LDLR-KO mice were fed a Western diet (0.15% cholesterol, WD), WD supplemented with 8-HEPE-concentrated materials from Pacific krill (8-HEPE included; WD +8-HEPE), or a standard diet (SD) for eighteen weeks, respectively. Murine J774.1 macrophages were incubated in the absence or presence of 8-HEPE (50 µM) or EPA (50 µM). 8-HEPE-concentrated materials significantly increased the plasma high-density lipoprotein (HDL)-cholesterol level, and decreased the plasma LDL-cholesterol and hepatic triglyceride levels in WD-fed LDLR-KO mice. Moreover, the rate of Oil Red O-positive staining was higher in the liver of WD-fed LDLR-KO mice than in that of 8-HEPE + WD-fed LDLR-KO mice. 8-HEPE but not EPA significantly increased gene expression levels of ABCA1, CD36, and interleukin 6 (IL-6) in murine J774.1 macrophages compared with those in the control. These results suggest that 8-HEPE-concentrated materials improve dyslipidemia and hepatic steatosis increasing ABCA1, CD36, and IL-6 gene expressions in macrophages.

SGLT1 participates in the development of vascular cognitive impairment in a mouse model of small vessel disease.

Sodium/glucose cotransporter 1 (SGLT1) participates in ischemia-reperfusion-induced cerebral injury. However, whether SGLT1 participates in the development of small vessel disease induced-vascular cognitive impairment is unknown. We examined the roles of SGLT1 in the development of vascular cognitive impairment in a mouse model of small vessel disease. Small vessel disease was created by placement of an ameroid constrictor around the right common carotid artery (CCA) and placement of a microcoil around the left CCA (ACAS) in wild-type (WT) and SGLT1-knock out (KO) mice. Two and/or 4 weeks after ACAS, all experiments were performed. Hematoxylin/eosin staining demonstrated that the number of pyknotic cell deaths was greater in the ACAS WT than ACAS SGLT1-KO hippocampus. The latency to fall in a wire hang test was significantly shorter in ACAS than sham-operated WT mice, whereas it was similar between ACAS and sham-operated SGLT1-KO mice. The Morris water maze test revealed that ACAS WT mice exhibited longer escape latencies than ACAS SGLT1-KO mice. ACAS significantly increased SGLT1 gene expression in WT mouse brains. Gene expressions of MCP-1, IL-1ß, TNF-α, and IL-6 were increased in ACAS WT compared with sham-operated WT mouse brains. Their increased gene expressions were significantly decreased in ACAS SGLT1-KO compared with ACAS WT mice. These results suggest that SGLT1 plays important roles in the development of small vessel dementia.

Pretreatment with KGA-2727, a selective SGLT1 inhibitor, is protective against myocardial infarction-induced ventricular remodeling and heart failure in mice.

Recent studies demonstrated that sodium-glucose co-transporter 1 (SGLT1) is associated with human ischemic cardiomyopathy. However, whether SGLT1 blockade is effective against ischemic cardiomyopathy is still uncertain. We examined the effects of KGA-2727, a selective SGLT1 inhibitor, on myocardial infarction (MI)-induced ischemic cardiomyopathy. To create MI, left anterior descending coronary artery (LAD) ligation with or without KGA-2727 administration was performed in C57BL/6J mice. Four weeks after the operation, all mice were investigated. Left ventricular fractional shortening (LVFS) was reduced and KGA-2727 significantly improved it in LAD-ligated MI mice. The cardiomyocyte diameter, and ANP, BNP, ß-MHC, and IL-18 gene expressions significantly increased in LAD-ligated mouse left ventricles compared with those of sham-operated mouse left ventricles, and KGA-2727 inhibited increases in them. Myocardial fibrosis and upregulation of CTGF and MMP-3 gene expressions in the left ventricle were increased in LAD-ligated mice compared with sham-operated mice, and KGA-2727 decreased them in the LAD-ligated left ventricles. SGLT1 protein expression level was significantly higher in LAD-ligated compared with sham-operated mouse ventricles regardless of KGA-2727 treatment. These results suggest that KGA-2727 pretreatment protects against MI-induced left ventricular remodeling through SGLT1 blockade and that it may become a new pharmacological therapy for ischemia-induced cardiomyopathy.

Cardiac overexpression of perilipin 2 induces atrial steatosis, connexin 43 remodeling, and atrial fibrillation in aged mice.

Atrial fibrillation (AF) is prevalent in patients with obesity and diabetes, and such patients often exhibit cardiac steatosis. Since the role of cardiac steatosis per se in the induction of AF has not been elucidated, the present study was designed to explore the relation between cardiac steatosis and AF. Transgenic (Tg) mice with cardiac-specific overexpression of perilipin 2 (PLIN2) were housed in the laboratory for more than 12 mo before the study. Electron microscopy of the atria of PLIN2-Tg mice showed accumulation of small lipid droplets around mitochondrial chains, and five- to ninefold greater atrial triacylglycerol (TAG) content compared with wild-type (WT) mice. Electrocardiography showed significantly longer RR intervals in PLIN2-Tg mice than in WT mice. Transesophageal electrical burst pacing resulted in significantly higher prevalence of sustained (>5 min) AF (69%) in PLIN2-Tg mice than in WT mice (24%), although it was comparable in younger (4-mo-old) mice. Connexin 43 (Cx43), a gap junction protein, was localized at the intercalated disks in WT atria but was heterogeneously distributed on the lateral side of cardiomyocytes in PLIN2-Tg atria. Langendorff-perfused hearts using the optical mapping technique showed slower and heterogeneous impulse propagation in PLIN2-Tg atria compared with WT atria. Cardiac overexpression of hormone-sensitive lipase in PLIN2-Tg mice resulted in atrial TAG depletion and amelioration of AF susceptibility. The results suggest that PLIN2-induced steatosis is associated with Cx43 remodeling, impaired conduction propagation, and higher incidence of AF in aged mice. Therapies targeting cardiac steatosis could be potentially beneficial against AF in patients with obesity or diabetes.

IL-1ß Plays an Important Role in Pressure Overload-Induced Atrial Fibrillation in Mice.

Hypertension is one risk for atrial fibrillation (AF) and induces cardiac inflammation. Recent evidence indicates that pressure overload-induced ventricular structural remodeling is associated with the activation of nucleotide binding-oligomerization domain (NOD)-like receptor P3 (NLRP3) inflammasomes, including an apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC). We hypothesized that NLRP3 inflammasomes are an initial sensor for danger signals in pressure overload-induced atrial remodeling, leading to AF. Transverse aortic constriction (TAC) or a sham procedure was performed in mice deficient for ASC-/- and interleukin-1ß (IL-1ß-/-). One week after the procedure, electrical left atrial burst pacing from the esophagus was performed for 30 s to induce AF. IL-1ß, monocyte chemotactic protein 1 (MCP-1), connective tissue growth factor (CTGF), and collagen 1 gene expression were also examined. The electrical burst pacing induced AF in TAC-operated wild-type (WT) (p < 0.001) and ASC-/- (p < 0.05) mice, compared to no AF in the sham-operated WT and ASC-/- mice, respectively. In contrast, the number of mice in which sustained AF was induced was similar between TAC-operated IL-1ß-/- and sham-operated IL-1ß-/- mice (p > 0.05). The expression of all genes tested was increased in TAC-operated WT and ASC-/- mice compared with sham-operated WT and ASC-/- mouse atria, respectively. CTGF and collagen 1, but not MCP-1, gene expressions were increased in TAC-operated IL-1ß-/- mouse atria compared with sham-operated WT and IL-1ß-/- mouse atria. In contrast, the IL-1ß gene was not detected in either TAC-operated or sham-operated IL-1ß-/- mouse atria. These results suggest that an IL-1ß activation pathway, different from NLRP3 inflammasomes, plays an important role in pressure overload-induced sustained AF.

Chronic Pressure Overload Induces Cardiac Hypertrophy and Fibrosis via Increases in SGLT1 and IL-18 Gene Expression in Mice.

Increased gene expression levels of sodium-glucose cotransporter 1 (SGLT1) are associated with hypertrophic and ischemic cardiomyopathy. However, it remains unclear whether chronic pressure overload increases SGLT1 expression, which in turn induces hypertrophic cardiomyopathy. We hypothesized that pressure overload could increase SGLT1 gene expression, leading to the development of hypertrophic cardiomyopathy.To create pressure overload-induced cardiomyopathy, transverse aortic constriction (TAC) was performed in SGLT1-deficient (SGLT1-/-) and wild-type (WT) mice. Six weeks after surgery, all mice were investigated. We observed a reduction of left ventricular fractional shortening and left ventricular dilatation in TAC-operated WT but not in TAC-operated SGLT1-/- mice. SGLT1, interleukin 18, connective tissue growth factor, and collagen type 1 gene expression levels were increased in TAC-operated WT mouse hearts compared with that of sham-operated WT mouse hearts. Moreover, heart/body weight ratio and ventricular interstitial fibrosis were increased in TAC-operated WT mice compared with that of sham-operated WT mice. Interestingly, these factors did not increase in TAC-operated SGLT1-/- mice compared with that of sham-operated WT and SGLT1-/- mice. Phenylephrine, an adrenergic α1 receptor agonist, caused cardiomyocyte hypertrophy in neonatal WT mouse hearts to a significantly larger extent than in neonatal SGLT1-/- mouse hearts.In conclusion, the results indicate that chronic pressure overload increases SGLT1 and IL-18 gene expressions, leading to the development of hypertrophic cardiomyopathy. These results make SGLT1 a potential candidate for the therapeutic target for hypertension-induced cardiomyopathy.

[Roles of Sodium-Glucose Cotransporter 1 (SGLT1) in the Induction of Cardiac Remodeling].

　It is well-known that metabolic remodeling occurs in the presence of cardiomyopathy induced by cardiac ischemia and hypertrophy, and diabetes mellitus. It is also known that a novel cardiac glucose transporter, sodium-glucose co-transporter 1 (SGLT1), is expressed in the human heart. However, the role of SGLT1 in the development of cardiac metabolic remodeling is still unclear. Recent studies demonstrated that SGLT1 activation improves ischemia-reperfusion-induced cardiac injury, and increased SGLT1 gene expression is observed in hypertrophic, ischemic, and diabetic cardiomyopathy in human hearts. Moreover, increases in SGLT1 protein expression cause cardiac remodeling such as hypertrophy and increased interstitial fibrosis in mice. We demonstrated that ischemia-reperfusion-induced cardiac injury was potentiated in SGLT1-deficient mice. In contrast, chronic pressure overload induced by transverse aortic constriction (TAC) caused cardiac hypertrophy and reduced left ventricular fractional shortening in C57BL/6J wild-type mice. Moreover, the TAC-induced hypertrophied heart showed increased SGLT1 and AMPKαprotein expressions. These results suggest the different effects of SGLT1 activation on cardiac diseases such as acute ischemia-reperfusion-induced cardiac injury and chronically-induced cardiac hypertrophy. Thus, SGLT1 may be a novel therapeutic target for the treatment of patients with cardiac diseases such as ischemic and hypertrophic cardiomyopathy.

Bcl-2-associated athanogene 3 (BAG3) is an enhancer of small heat shock protein turnover via activation of autophagy in the heart.

Bcl-2-associated athanogene 3 (BAG3) is strongly expressed in both cardiac and skeletal muscle. A recent study showed that BAG3 may play a protective role in muscles. Little is known, however, regarding the detailed role of BAG3 in cardiac muscle. To better understand the functional role of cardiac BAG3 in the heart, we generated transgenic (TG) mice that overexpress BAG3. A decrease in fractional shortening, and the induction of cardiac atrial natriuretic peptide, were observed in BAG3 TG mice. Moreover, a marked reduction in the protein level of small HSPs was detected in BAG3 TG mouse hearts. We analyzed the cardiac small HSP levels when either the ubiquitin-proteasome system (UPS) or the autophagy system (AS) was inhibited in BAG3 TG mice. The protein turnovers of small HSPs by the AS were activated in BAG3 TG mouse hearts. Thus, BAG3 is critical for the protein turnover of small HSPs via activation of autophagy in the heart.

Cardiac overexpression of perilipin 2 induces dynamic steatosis: prevention by hormone-sensitive lipase.

Cardiac intracellular lipid accumulation (steatosis) is a pathophysiological phenomenon observed in starvation and diabetes mellitus. Perilipin 2 (PLIN2) is a lipid droplet (LD)-associated protein expressed in nonadipose tissues, including the heart. To explore the pathophysiological function of myocardial PLIN2, we generated transgenic (Tg) mice by cardiac-specific overexpression of PLIN2. Tg hearts showed accumulation of numerous small LDs associated with mitochondrial chains and high cardiac triacylglycerol (TAG) content [8-fold greater than wild-type (WT) mice]. Despite massive steatosis, cardiac uptake of glucose, fatty acids and VLDL, systolic function, and expression of metabolic genes were comparable in the two genotypes, and no morphological changes were observed by electron microscopy in the Tg hearts. Twenty-four hours of fasting markedly reduced steatosis in Tg hearts, whereas WT mice showed accumulation of LDs. Although activity of adipose triglyceride lipase in heart homogenate was comparable between WT and Tg mice, activity of hormone-sensitive lipase (HSL) was 40-50% less in Tg than WT mice under both feeding and fasting conditions, suggesting interference of PLIN2 with HSL. Mice generated through crossing of PLIN2-Tg mice and HSL-Tg mice showed cardiac-specific HSL overexpression and complete lack of steatosis. The results suggest that cardiac PLIN2 plays an important pathophysiological role in the development of dynamic steatosis and that the latter was prevented by upregulation of intracellular lipases, including HSL.

8-Hydroxyeicosapentaenoic Acid Decreases Plasma and Hepatic Triglycerides via Activation of Peroxisome Proliferator-Activated Receptor Alpha in High-Fat Diet-Induced Obese Mice.

PPARs regulate the expression of genes involved in lipid homeostasis. PPARs serve as molecular sensors of fatty acids, and their activation can act against obesity and metabolic syndromes. 8-Hydroxyeicosapentaenoic acid (8-HEPE) acts as a PPAR ligand and has higher activity than EPA. However, to date, the PPAR ligand activity of 8-HEPE has only been demonstrated in vitro. Here, we investigated its ligand activity in vivo by examining the effect of 8-HEPE treatment on high fat diet-induced obesity in mice. After the 4-week treatment period, the levels of plasma and hepatic triglycerides in the 8-HEPE-fed mice were significantly lower than those in the HFD-fed mice. The expression of genes regulated by PPARα was significantly increased in 8-HEPE-fed mice compared to those that received only HFD. Additionally, the level of hepatic palmitic acid in 8-HEPE-fed mice was significantly lower than in HFD-fed mice. These results suggested that intake of 8-HEPE induced PPARα activation and increased catabolism of lipids in the liver. We found no significant differences between EPA-fed mice and HFD-fed mice. We demonstrated that 8-HEPE has a larger positive effect on metabolic syndrome than EPA and that 8-HEPE acts by inducing PPARα activation in the liver.

Transplantation of adipose tissue-derived stem cells improves cardiac contractile function and electrical stability in a rat myocardial infarction model.

The transplantation of adipose tissue-derived stem cells (ADSCs) improves cardiac contractility after myocardial infarction (MI); however, little is known about the electrophysiological consequences of transplantation. The purpose of this study was to clarify whether the transplantation of ADSCs increases or decreases the incidence of ventricular tachyarrhythmias (VT) in a rat model of MI. MI was induced experimentally by permanent occlusion of the left anterior descending artery of Lewis rats. ADSCs were harvested from GFP-transgenic rats, and were cultured until passage four. ADSCs (10×10(6)) resuspended in 100µL saline or pro-survival cocktail (PSC), which enhances cardiac graft survival, were injected directly into syngeneic rat hearts 1week after MI. The recipients of ADSCs suspended in PSC had a larger graft area compared with those receiving ASDCs suspended in saline at 1week post-transplantation (number of graft cells/section: 148.7±10.6 vs. 22.4±3.4, p<0.05, n=5/group). Thereafter, all ADSC recipients were transplanted with ASDCs in PSC. ADSCs were transplanted into infarcted hearts, and the mechanical and electrophysiological functions were assessed. Echocardiography revealed that ADSC recipients had improved contractile function compared with those receiving PSC vehicle (fractional shortening: 21.1±0.9 vs. 14.1±1.2, p<0.05, n≥12/group). Four weeks post-transplantation, VT was induced via in vivo programmed electrical stimulation. The recipients of ADSCs showed a significantly lower incidence of induced VT compared with the control (31.3% vs. 83.3%, p<0.05, n≥12/group). To understand the electrical activity following transplantation, we performed ex vivo optical mapping using a voltage sensitive dye, and found that ADSC transplantation decreased conduction velocity and its dispersion in the peri-infarct area. These results suggest that ADSC transplantation improved cardiac mechanical and electrophysiological functions in subacute MI.