Yukinori Ikegami

Novel Cardiac Precursor‐Like Cells from Human Menstrual Blood‐Derived Mesenchymal Cells

Stem cell therapy can help repair damaged heart tissue. Yet many of the suitable cells currently identified for human use are difficult to obtain and involve invasive procedures. In our search for novel stem cells with a higher cardiomyogenic potential than those available from bone marrow, we discovered that potent cardiac precursor‐like cells can be harvested from human menstrual blood. This represents a new, noninvasive, and potent source of cardiac stem cell therapeutic material. We demonstrate that menstrual blood‐derived mesenchymal cells (MMCs) began beating spontaneously after induction, exhibiting cardiomyocyte‐specific action potentials. Cardiac troponin‐I‐positive cardiomyocytes accounted for 27%–32% of the MMCs in vitro. The MMCs proliferated, on average, 28 generations without affecting cardiomyogenic transdifferentiation ability, and expressed mRNA of GATA‐4 before cardiomyogenic induction. Hypothesizing that the majority of cardiomyogenic cells in MMCs originated from detached uterine endometrial glands, we established monoclonal endometrial gland‐derived mesenchymal cells (EMCs), 76%–97% of which transdifferentiated into cardiac cells in vitro. Both EMCs and MMCs were positive for CD29, CD105 and negative for CD34, CD45. EMCs engrafted onto a recipients heart using a novel 3‐dimensional EMC cell sheet manipulation transdifferentiated into cardiac tissue layer in vivo. Transplanted MMCs also significantly restored impaired cardiac function, decreasing the myocardial infarction (MI) area in the nude rat model, with tissue of MMC‐derived cardiomyocytes observed in the MI area in vivo. Thus, MMCs appear to be a potential novel, easily accessible source of material for cardiac stem cell‐based therapy.

Xenografted Human Amniotic Membrane–Derived Mesenchymal Stem Cells Are Immunologically Tolerated and Transdifferentiated Into Cardiomyocytes

Rationale: Amniotic membrane is known to have the ability to transdifferentiate into multiple organs and is expected to stimulate a reduced immunologic reaction. Objective: Determine whether human amniotic membrane–derived mesenchymal cells (hAMCs) can be an ideal allograftable stem cell source for cardiac regenerative medicine. Methods and Results: We established hAMCs. After cardiomyogenic induction in vitro, hAMCs beat spontaneously, and the calculated cardiomyogenic transdifferentiation efficiency was 33%. Transplantation of hAMCs 2 weeks after myocardial infarction improved impaired left ventricular fractional shortening measured by echocardiogram (34±2% [n=8] to 39±2% [n=11]; P<0.05) and decreased myocardial fibrosis area (18±1% [n=9] to 13±1% [n=10]; P<0.05), significantly. Furthermore hAMCs transplanted into the infarcted myocardium of Wistar rats were transdifferentiated into cardiomyocytes in situ and survived for more than 4 weeks after the transplantation without using any immunosuppressant. Immunologic tolerance was caused by the hAMC-derived HLA-G expression, lack of MHC expression of hAMCs, and activation of FOXP3-positive regulatory T cells. Administration of IL-10 or progesterone, which is known to play an important role in feto-maternal tolerance during pregnancy, markedly increased HLA-G expression in hAMCs in vitro and, surprisingly, also increased cardiomyogenic transdifferentiation efficiency in vitro and in vivo. Conclusions: Because hAMCs have a high ability to transdifferentiate into cardiomyocytes and to acquire immunologic tolerance in vivo, they can be a promising cellular source for allograftable stem cells for cardiac regenerative medicine.

The Significant Cardiomyogenic Potential of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells In Vitro

We tested the cardiomyogenic potential of the human umbilical cord blood‐derived mesenchymal stem cells (UCBMSCs). Both the number and function of stem cells may be depressed in senile patients with severe coronary risk factors. Therefore, stem cells obtained from such patients may not function well. For this reason, UCBMSCs are potentially a new cell source for stem cell‐based therapy, since such cells can be obtained from younger populations and are being routinely utilized for clinical patients. The human UCBMSCs (5 × 103 per cm2) were cocultured with fetal murine cardiomyocytes ([CM] 1 × 105 per cm2). On day 5 of cocultivation, approximately half of the green fluorescent protein (GFP)‐labeled UCBMSCs contracted rhythmically and synchronously, suggesting the presence of electrical communication between the UCBMSCs. The fractional shortening of the contracted UCBMSCs was 6.5% ± 0.7% (n = 20). The UCBMSC‐derived cardiomyocytes stained positive for cardiac troponin‐I (clear striation +) and connexin 43 (diffuse dot‐like staining at the margin of the cell) by the immunocytochemical method. Cardiac troponin‐I positive cardiomyocytes accounted for 45% ± 3% of GFP‐labeled UCBMSCs. The cardiomyocyte‐specific long action potential duration (186 ± 12 milliseconds) was recorded with a glass microelectrode from the GFP‐labeled UCBMSCs. CM were observed in UCBMSCs, which were cocultivated in the same dish with mouse cardiomyocytes separated by a collagen membrane. Cell fusion, therefore, was not a major cause of CM in the UCBMSCs. Approximately half of the human UCBMSCs were successfully transdifferentiated into cardiomyocytes in vitro. UCBMSCs can be a promising cellular source for cardiac stem cell‐based therapy.

Serum‐independent Cardiomyogenic Transdifferentiation in Human Endometrium‐derived Mesenchymal Cells

Media with high concentrations of serum are commonly used to induce cardiomyogenic transdifferentiation in mesenchymal stem cells; however, serum contains numerous unknown growth factors and interferes with definition of specific cardiomyogenic transdifferentiation factors secreted from feeder cells. In the present study, we determined whether the transdifferentiation of human mesenchymal cells can be observed in a FBS-free medium. The efficiency of transdifferentiation was observed in 10% FBS-containing standard medium (10%FBS) and in FBS-free medium containing insulin and thyroxin (FBS-free). In the present study, we used human uterine endometrium-derived mesenchymal cells (EMC100, EMC214) and menstrual blood-derived mesenchymal cells (MMCs). After cardiomyogenic transdifferentiation, the efficiency and physiological properties of cardiomyogenesis (fractional shortening of the cell [%FS] and action potential [AP]) were evaluated. The efficiency of transdifferentiation in EMC100 and in MMCs increased 36%* and 163%* (*P < 0.05), respectively. The %FS in EMCs increased to 103%*. AP-duration more than 250 ms with a marked plateau was only observed in FBS-free (3/19), and not in 10% FBS (0/41). The cardiomyogenic transdifferentiation of human mesenchymal cells can be observed in the FBS-free medium. Phenotypes of generated cardiomyocytes were significantly more physiological in FBS-free than in 10% FBS.

Outcomes of Percutaneous Coronary Intervention Performed With or Without Preprocedural Dual Antiplatelet Therapy

BACKGROUND Preprocedural dual antiplatelet therapy (DAPT) in percutaneous coronary interventions (PCI) has been shown to improve outcomes; however, the efficacy of the procedure and its complications in Japanese patients remain largely unexplored, so we examined the risks and benefits of DAPT before PCI and its association with in-hospital outcomes. METHODSANDRESULTS We analyzed data from patients who had undergone PCI at 12 centers within the metropolitan Tokyo area between September 2008 and September 2013.Our study group comprised 6,528 patients, of whom 2,079 (31.8%) were not administered preprocedural DAPT. Non-use of preprocedural DAPT was associated with death, postprocedural shock, or heart failure (odds ratio [OR]: 1.47, 95% confidence interval [CI]: 1.10-1.96, P=0.009), and postprocedural myocardial infarction (OR: 1.41, 95% CI: 1.18-1.69, P<0.001) after adjusting propensity scores for known predictors of in-hospital complications. Non-use of DAPT was not associated with procedure-related bleeding complications (OR: 0.98, 95% CI: 0.71-1.59, P=0.764). CONCLUSIONS Approximately one-third of the patients who underwent PCI did not receive preprocedural DAPT despite guideline recommendations. Our results indicate that patients undergoing PCI with DAPT have a lower risk of postprocedural cardiac events without any increased bleeding risk. Further studies are needed to implement the use of DAPT in real-world PCI.

Plasma Soluble Endoglin Levels Are Inversely Associated With the Severity of Coronary Atherosclerosis

Objective— Transforming growth factor-&bgr; inhibits migration and proliferation of endothelial and smooth muscle cells. Endoglin is a transmembrane receptor for transforming growth factor-&bgr;1 and transforming growth factor-&bgr;3. Endoglin is released into blood as a soluble form (soluble endoglin [sEng]), but plasma sEng levels in patients with coronary artery disease (CAD) have not been elucidated. Approach and Results— We measured plasma sEng levels in 244 patients undergoing coronary angiography. The severity of coronary atherosclerosis was evaluated as the numbers of >50% stenotic vessels and segments. CAD was found in 147 patients, of whom 55 had 1-vessel, 42 had 2-vessel, and 50 had 3-vessel disease. Compared with 97 patients without CAD, 147 with CAD had lower sEng levels (median 4.04 versus 4.37 ng/mL; P<0.005). A stepwise decrease in sEng levels was found based on the number of stenotic vessels: 4.37 in CAD(−), 4.23 in 1-vessel, 4.13 in 2-vessel, and 3.74 ng/mL in 3-vessel disease (P<0.005). sEng levels inversely correlated with the number of stenotic segments (r=−0.25; P<0.001). In multivariate analysis, sEng was an independent factor for 3-vessel disease and CAD. Odds ratios for CAD and 3-vessel disease were 0.97 (95% confidence interval, 0.95–0.99; P<0.02) and 0.96 (95% confidence interval, 0.93–0.99; P<0.01) for a 0.1 ng/mL increase in sEng levels, respectively. Conclusions— Plasma sEng levels were low in patients with CAD, especially 3-vessel disease, and were inversely associated with the severity of coronary atherosclerosis.

Identification of Left Atrial Appendage Thrombi in Patients With Persistent and Long-Standing Persistent Atrial Fibrillation Using Intra-Cardiac Echocardiography and Cardiac Computed Tomography

BACKGROUND Intracardiac echocardiography (ICE) and cardiac computed tomography (CCT), in addition to standard transesophageal echocardiography (TEE), have been used to identify left atrial (LA) thrombi prior to ablation for atrial fibrillation (AF). The clinical advantages of this, however, remain unclear. This study therefore investigated the advantages of additional pre-procedural LA appendage (LAA) thrombus evaluation using ICE and the clinical value of CCT in persistent and long-standing persistent AF.Methods and Results:We analyzed data from 108 consecutive patients with persistent and long-standing persistent AF who were scheduled to undergo AF ablation. TEE was performed within 24 h prior to ablation. ICE was performed for 97 patients in whom a thrombus was not detected on TEE. CCT was performed in 95 patients. Thrombus or sludge was detected on TEE in 11 patients (10.3%), for whom ablation was cancelled. Four additional patients were diagnosed with LAA thrombus on ICE. When TEE and ICE were used as the reference for thrombus detection, the sensitivity, specificity, positive predictive value, and negative predictive value of CCT for identifying contrast defects in the LAA were 100%, 81.0%, 40.7%, and 100%, respectively. CONCLUSIONS ICE combined with TEE increased the detection rate of LAA thrombi in patients with persistent and long-standing persistent AF. Moreover, CCT had high sensitivity and negative predictive value for LAA thrombus detection.

Efficacy of tolvaptan in a patient with right-sided heart failure and renal dysfunction refractory to diuretic therapy

The use of loop diuretics has been shown to deteriorate renal dysfunction and is associated with a poor prognosis in patients with heart failure (HF). Tolvaptan, a vasopressin V2-receptor antagonist, has been reported to be effective in treating HF due to its potent effects of water diuresis and is expected to improve fluid retention without adversely affecting renal function. The present case is a 77-year-old man with pulmonary hypertension associated with chronic pulmonary artery thrombosis and old pulmonary tuberculosis who developed worsening right-sided HF with marked fluid retention and renal dysfunction. In this case, tolvaptan was effective in improving HF without deteriorating the patients renal dysfunction. <Learning objective: Tolvaptan is effective in treating patients with right-sided heart failure associated with marked fluid retention and renal dysfunction who are refractory to loop diuretics and can improve and control heart failure symptoms without worsening renal dysfunction.>.

Low Plasma Levels of Fibroblast Growth Factor-21 in Patients with Peripheral Artery Disease

Aim: Fibroblast growth factor-21 (FGF-21) is a metabolic regulator with beneficial effects on glucolipid metabolism. Since FGF-21 has lipid-lowering, anti-inflammatory and anti-oxidant properties, it may play a protective role against atherosclerosis. However, blood FGF-21 levels in coronary artery disease (CAD) or peripheral artery disease (PAD) have not been elucidated. Methods: We measured plasma FGF-21 levels in 417 patients undergoing coronary angiography, who also had ankle-brachial index test for PAD screening. Results: CAD was found in 224 patients (1-vessel [1-VD], n = 92; 2-vessel [2-VD], n = 65; 3-vessel disease [3-VD], n = 67). No significant difference was found in the FGF-21 levels between 224 patients with CAD and 193 without CAD (median 26.0 vs. 25.9 pg/mL). FGF-21 levels in 4 groups of CAD(−), 1-VD, 2-VD, and 3-VD were 25.9, 37.2, 19.4, and 0.0 pg/mL. FGF-21 tended to be highest in 1-VD and lowest in 3-VD, but the difference did not reach statistical significance. PAD was found in 38 patients. Compared to the 379 patients without PAD, 38 with PAD had CAD more often (87% vs. 50%), especially 3-VD (P < 0.001). FGF-21 levels were lower in patients with PAD than in those without PAD (0.0 vs. 30.7 pg/mL, P < 0.02). In multivariate analysis, the FGF-21 level was an independent factor for PAD, but not for CAD. Odds ratio for PAD was 2.13 (95%CI= 1.01–4.49) for a low FGF-21 level (< 15.6 pg/mL). Conclusion: No significant difference was found in the FGF-21 levels between patients with and without CAD. However, FGF-21 levels were low in patients with PAD, and were a factor for PAD independent of atherosclerotic risk factors.

Reversible Cardiomyopathy Accompanied by Secondary Adrenal Insufficiency

A 41-year-old woman was admitted to our hospital because of worsening dyspnea for 2 weeks. She experienced fatigue and shortness of breath on physical activity (5 metabolic equivalents) for 8 years after delivery, and she considered this normal. She also had meningitis 3 months before presentation that resolved in 2 weeks. There was no evidence of ischemia or infection, and she had no history of alcohol abuse or illegal drug use. Twelve-lead electrocardiography showed sinus rhythm with low voltage, chest radiography showed pulmonary congestion and a dilated cardiac silhouette (Figure 1A), echocardiography showed a dilated left ventricle (Figure 1B) with reduced ejection fraction of 25%, and cardiac magnetic resonance imaging demonstrated low ejection fraction without specific findings of inflammation, fibrosis, or deposition. Diuretic injection improved dyspnea in 2 days. Low-dose β-blocker administration was started for idiopathic cardiomyopathy with reduced ejection fraction; however, the β-blocker was discontinued because it caused hypotension. Two …