HLA-Ehigh /HLA-Ghigh /HLA-IIlow Human iPSC-Derived Cardiomyocytes Exhibit Low Immunogenicity for Heart Regeneration.

Although human pluripotent stem cells (hPSCs)-derived cardiomyocytes (hPSC-CMs) can remuscularize infarcted hearts and restore post-infarct cardiac function, post-transplant rejection resulting from human leukocyte antigen (HLA) mismatching is an enormous obstacle. It is crucial to identify hypoimmunogenic hPSCs for allogeneic cell therapy. This study is conducted to demonstrate the immune privilege of HLA-Ehigh /HLA-Ghigh /HLA-IIlow human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs). Ischemia-reperfusion surgery is done to create transmural myocardial infarction in rats. At post-infarct 4 days, hPSC-CMs (1.0×107 cells per kg), including human embryonic stem cell-derived cardiomyocytes (hESC-CMs), HLA-Elow/HLA-Glow/HLA-IIhigh hiPSC-CMs, and HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs, are injected into the infarcted myocardium. Under the treatment of very low dose cyclosporine A (CsA), only HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs survive in vivo and improved post-infarct cardiac function with infarct size reduction. HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs activate the SHP-1 signaling pathway of natural killer (NK) cells and cytotoxic T cells to evade attack by NK cells and cytotoxic T cells. Herein, it is demonstrated that using a clinically relevant CsA dose, HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSC-CMs repair the infarcted myocardium and restore the post-infarct heart function. HLA-Ehigh /HLA-Ghigh /HLA-IIlow hiPSCs are less immunogenic and may serve as platforms for regeneration medicine.

Progress and Challenges of Amniotic Fluid Derived Stem Cells in Therapy of Ischemic Heart Disease.

Cardiovascular disease is the leading cause of deaths worldwide, claiming an estimated total of 17.9 million lives each year, of which one-third of the people are under the age of 70 years. Since adult cardiomyocytes fail to regenerate, the heart loses the ability to repair itself after an injury, making patients with heart disease suffer from poor prognosis. Pluripotent stem cells have the ability to differentiate into cardiomyocytes in vitro through a well-established process, which is a new advancement in cardiac regeneration therapy. However, pluripotent stem cell-derived cardiomyocytes have certain drawbacks, such as the risk of arrhythmia and immune incompatibility. Thus, amniotic fluid stem cells (AFSCs), a relatively novel source of stem cells, have been exploited for their ability of pluripotent differentiation. In addition, since AFSCs are weakly positive for the major histocompatibility class II molecules, they may have high immune tolerance. In summary, the possibility of development of cardiomyocytes from AFSCs, as well as their transplantation in host cells to produce mechanical contraction, has been discussed. Thus, this review article highlights the progress of AFSC therapy and its application in the treatment of heart diseases in recent years.

Immunogenicity in Stem Cell Therapy for Cardiac Regeneration.

Despite enormous advances in the treatment of cardiovascular disease (CVD), heart disease remains the leading cause of mortality and morbidity worldwide. Thus, there is a need for novel CVD therapeutics. CVD appears to be a custom-made scenario for applying stem cell therapy. Although human pluripotent stem cells can differentiate into cardiomyocytes to regenerate injured heart tissue and restore post-myocardial infarction cardiac function, several obstacles need to be overcome before cell therapy can be applied in CVD patients. One of these major hurdles is the immunological barrier. Currently, long-term immunosuppressant treatment is necessary for allogenic stem cell or organ transplantation to prevent rejection. However, the long-term use of immunosuppressants may cause serious adverse events such as nephrotoxicity, severe infections and malignancy. Thus, overcoming this immunological hurdle is crucial for the clinical application of stem cell therapy in cardiac regeneration. This review summarizes the recent advances and challenges of immunogenicity in relation to stem cell therapy.

Efficient Cardiac Differentiation of Human Amniotic Fluid-Derived Stem Cells into Induced Pluripotent Stem Cells and Their Potential Immune Privilege.

Mature mammalian hearts possess very limited regenerative potential. The irreversible cardiomyocyte loss after heart injury can lead to heart failure and death. Pluripotent stem cells (PSCs) can differentiate into cardiomyocytes for cardiac repair, but there are obstacles to their clinical application. Among these obstacles is their potential for post-transplant rejection. Although human amniotic fluid-derived stem cells (hAFSCs) are immune privileged, they cannot induce cardiac differentiation. Thus, we generated hAFSC-derived induced PSCs (hAFSC-iPSCs) and used a Wnt-modulating differentiation protocol for the cardiac differentiation of hAFSC-iPSCs. In vitro studies using flow cytometry, immunofluorescence staining, and patch-clamp electrophysiological study, were performed to identify the characteristics of hAFSC-iPSC-derived cardiomyocytes (hAFSC-iPSC-CMs). We injected hAFSC-iPSC-CMs intramuscularly into rat infarcted hearts to evaluate the therapeutic potential of hAFSC-iPSC-CM transplantation. At day 21 of differentiation, the hAFSC-iPSC-CMs expressed cardiac-specific marker (cardiac troponin T), presented cardiomyocyte-specific electrophysiological properties, and contracted spontaneously. Importantly, these hAFSC-iPSC-CMs demonstrated low major histocompatibility complex (MHC) class I antigen expression and the absence of MHC class II antigens, indicating their low immunogenicity. The intramyocardial transplantation of hAFSC-iPSC-CMs restored cardiac function, partially remuscularized the injured region, and reduced fibrosis in the rat infarcted hearts. Therefore, hAFSC-iPSCs are potential candidates for the repair of infarcted myocardium.

Independent value of cardiac troponin T and left ventricular global longitudinal strain in predicting all-cause mortality among stable hemodialysis patients with preserved left ventricular ejection fraction.

Using a speckle-tracking echocardiography (STE), we recently demonstrated that a left ventricular (LV) global longitudinal strain (GLS) ≥ -15% and the serum cardiac troponin T (cTnT) concentration are associated with mortality in stable hemodialysis patients with preserved LV ejection fraction (LVEF). In this study, we explored the relationship between cTnT and echocardiographic parameters and evaluated whether the prognostic value provided by cTnT is independent of a GLS ≥ -15% and vice versa. Eighty-eight stable hemodialysis patients with preserved LVEF were followed for 31 months. STE studies and measurements of cTnT were performed at baseline. CTnT concentration had a modest correlation with GLS (rs = 0.44; P < 0.001) but had a weak or nonsignificant correlation with other echocardiographic parameters. Adjusting for clinical parameters, hazard ratios for each increase of 0.01 ng/mL in cTnT, and a GLS ≥ -15% on mortality were 1.13 (P = 0.009) and 3.09 (P = 0.03) without significant interaction between cTnT and GLS ≥ -15%. In addition, an increased cTnT concentration, a GLS ≥ -15%, or their combination showed significant additional predictive value for mortality when included in models consisting of clinical parameters. Therefore, both cTnT and a GLS ≥ -15% are independent predictors of mortality and are useful for risk stratification.

Elevated serum interleukin-18 level is associated with all-cause mortality in stable hemodialysis patients independently of cardiac dysfunction.

BACKGROUND: High circulating interleukin (IL)-18 level predicts a higher hospitalization rate among dialysis patients, possibly through cardiovascular mechanisms; however, whether higher IL-18 level is associated with mortality in dialysis patients is less clear. In addition, its impacts on left ventricular (LV) function are also unknown. We conducted a cohort study to examine the impacts of IL-18 level on LV function and prognosis among clinically stable hemodialysis patients. METHODS: Clinically stable patients undergoing maintenance hemodialysis (≥ 3 months) were prospectively enrolled from December 2008 to January 2009, and were followed up for 31 months. The enrolled patients (41% male, 66.4 ± 10.9 years of age) received 2-dimensional echocardiography and myocardial deformation (strain) analysis, including LV peak systolic longitudinal strain (GLS) and circumferential strain (CS). Laboratory measurements were also performed. Cox regression analysis was used to investigate prognostic factors. RESULTS: Seventy-five patients were stratified into 2 groups by the median value of IL-18 (654.2 pg/ml). Between these 2 groups, there was no significant difference in baseline characteristics including LV ejection fraction. The high IL-18 group had a worse LV systolic function as demonstrated by reduced GLS and CS. Seventeen patients (22.7%) died during the follow-up period. Multivariate Cox regression analysis showed that low serum albumin, the presence of hypertension, high serum IL-18, and less negative GLS (>-15%) were independently associated with all-cause mortality. No significant interaction between IL-18 and less negative GLS was noted in the final Cox model. CONCLUSION: Hemodialysis patients with high IL-18 levels tend to have worse LV systolic function and higher mortality rate. However, elevated serum IL-18 level is predictive of poor prognosis among stable hemodialysis patients, independently of LV dysfunction. This suggests an additional value of IL-18 to echocardiographic study in predicting all-cause mortality, and IL-18 may be helpful in early risk stratification of hemodialysis patients.

Association of left ventricular longitudinal strain with mortality among stable hemodialysis patients with preserved left ventricular ejection fraction.

BACKGROUND AND OBJECTIVES: Little is known about the optimal echocardiographic parameters for risk stratification in stable dialysis patients with preserved left ventricular ejection fraction (LVEF) (ejection fraction ≥ 50%). Left ventricular (LV) global peak systolic longitudinal strain (GLS) is the ratio of the maximal change in myocardial longitudinal length in systole to the original length and reliably and accurately assesses LV function. During systole, LV myocardium in the longitudinal direction shortens and GLS is represented by a negative value. The more negative value of GLS, the better the LV function is. This study hypothesized that subtle abnormalities of GLS are associated with an adverse prognosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This prospective study collected clinical and echocardiographic data (including GLS) from 88 stable hemodialysis patients (mean age 67.0 ± 11.2 years; 35% men) with preserved LVEF. These patients were enrolled from December 2008 to January 2009 and were followed-up for 25.6 ± 9.9 months. The primary outcome was all-cause mortality. Multivariate Cox regression analysis was used to investigate risk factors for mortality. RESULTS: The mortality group (n=24) had lower albumin levels, less negative GLS, and higher prevalence of coronary artery disease and diabetes mellitus than the survival group. Using a GLS cutoff value of -15%, the less negative GLS group (GLS ≥-15%) had a higher mortality rate. Cox regression analyses revealed that lower albumin level (hazard ratio, 0.16; 95% confidence interval, 0.05 to 0.53; P=0.003) and less negative GLS (hazard ratio, 3.57; 95% confidence interval, 1.41 to 9.04; P=0.01) were independent predictors of all-cause mortality. Furthermore, less negative GLS was associated with a higher cardiovascular death rate. CONCLUSIONS: Less negative GLS is predictive of poor prognosis among stable hemodialysis patients with preserved LVEF.

Xenografted human amniotic fluid-derived stem cell as a cell source in therapeutic angiogenesis.

BACKGROUND: Amniotic fluid-derived stem cells (AFSCs) are pluripotent with high renewal capacity and are not tumorigenic. We tested whether AFSCs can function as a cell source for therapeutic angiogenesis in a mouse hindlimb ischemia model. METHODS: Using a defined culture medium for endothelial lineage cells (ECs), we differentiated human AFSCs into AFSC-derived ECs (AFSC-ECs) in vitro, as evidenced by expression of EC markers, and capillary-like network formation on Matrigel. We assessed the in vivo therapeutic angiogenesis efficacy of AFSC-ECs in an athymic nude mouse model of hindlimb ischemia. One day after high ligation of the external iliac artery in athymic nude mice, AFSC-ECs were intramuscularly injected into ischemic limbs. RESULTS: The AFSC-ECs demonstrated endothelial cell characteristics in vitro. Four weeks later, AFSC-ECs transplantation significantly increased limb salvage (85%), compared to AFSCs (56%), human umbilical vein endothelial cells (HUVECs; 25%), or medium (0%). Laser Doppler perfusion analysis revealed that the ischemic/normal limb blood perfusion ratio significantly improved in the AFSC-EC group. AFSC-EC transplantation significantly increased capillary and arteriole densities as compared to AFSCs, HUVECs, and medium. Transplanted AFSC-ECs were incorporated into vessels in the ischemic region, as confirmed by immunofluorescent staining for human smooth muscle 22α or von Willebrand factor. Matrix metalloproteinase (MMP)-3 and MMP-9 expressions were significantly higher in AFSC-ECs. MMP-9 might activate angiogenesis by regulation of vascular endothelial growth factor. CONCLUSIONS: Our study indicated that AFSC-EC transplantation improved limb salvage and blood perfusion by promoting neovascularization. Therefore, AFSC-ECs possess the potential for therapeutic angiogenesis.

Application of speckle-tracking echocardiography in detecting coronary artery disease in patients with maintenance hemodialysis.

BACKGROUND: Satisfactory and noninvasive diagnostic tools for coronary artery disease (CAD) are not available in hemodialysis patients. We aimed to elucidate a reliable tool to diagnose CAD in these patients. METHODS: 102 hemodialysis patients received 2D speckle-tracking echocardiography with left ventricular (LV) strain analysis and blood tests for cardiac troponin T, high-sensitive C-reactive protein, interleukin (IL)-6, and IL-18. RESULTS: The levels of biomarkers did not differ between patients with and without CAD. The factors associated with CAD were decreased circumferential strain, decreased global longitudinal strain, and the number of LV segments with decreased longitudinal strain. Logistic regression analyses showed that the number of LV segments with decreased longitudinal strain, over 6 segments, was strongly associated with CAD in hemodialysis patients (OR 12.08, 95% CI 3.724-39.209). CONCLUSIONS: The noninvasive modality of speckle-tracking echocardiography with strain analysis is efficient and objective for identifying CAD in hemodialysis patients.

Clinical significance of serum human papillomavirus DNA in cervical carcinoma.

OBJECTIVE: To study the association between serum human papillomavirus (HPV) deoxyribonucleic acid (DNA) and clinicopathologic prognostic factors and the clinical usefulness of serum HPV DNA in early-stage cervical cancer. METHODS: Deoxyribonucleic acids extracted from cervical tissues and sera of patients with stage IB or IIA cervical cancer and 40 controls including patients with cervical carcinoma in situ or benign disease were examined for HPV DNA with L1 consensus and types 16- and 18-specific E7 primers. Multivariable logistic regression was used to determine significant correlates of positive serum HPV DNA, and the receiver operating characteristic curve was applied in risk-factor assessment. RESULTS: Human papillomavirus DNA was not detected in sera from patients with carcinoma in situ or benign disease. Among the 112 patients with cervical cancer, we detected 27 positive samples (24.1%) in serum. Positive HPV DNA in serum was significantly associated with lymphovascular invasion and deep stromal invasion with or without parametrial extension (P <.001 for both conditions), pelvic lymph nodal metastasis (P =.001), large tumor size, and elevated levels of serum squamous cell carcinoma antigen (P <.001 for both conditions). When serum HPV DNA was used to predict high-risk patients who require adjuvant therapy, a sensitivity of 45.2%, a specificity of 88.6%, a positive predictive value of 70.4%, and a negative predictive value of 72.9% were obtained. CONCLUSION: The presence of serum HPV DNA in patients with early-stage cervical cancer was correlated with poor prognosis factors that warrant adjuvant therapy.