Bioderived Nanoparticles for Cardiac Repair.

Biobased therapy represents a promising strategy for myocardial repair. However, the limitations of using live cells, including the risk of immunogenicity of allogeneic cells and inconsistent therapeutic efficacy of autologous cells together with low stability, result in an unsatisfactory clinical outcomes. Therefore, cell-free strategies for cardiac tissue repair have been proposed as alternative strategies. Cell-free strategies, primarily based on the paracrine effects of cellular therapy, have demonstrated their potential to inhibit apoptosis, reduce inflammation, and promote on-site cell migration and proliferation, as well as angiogenesis, after an infarction and have been explored preclinically and clinically. Among various cell-free modalities, bioderived nanoparticles, including adeno-associated virus (AAV), extracellular vesicles, cell membrane-coated nanoparticles, and exosome-mimetic nanovesicles, have emerged as promising strategies due to their improved biological function and therapeutic effect. The main focus of this review is the development of existing cellular nanoparticles and their fundamental working mechanisms, as well as the challenges and opportunities. The key processes and requirements for cardiac tissue repair are summarized first. Various cellular nanoparticle modalities are further highlighted, together with their advantages and limitations. Finally, we discuss various delivery approaches that offer potential pathways for researchers and clinicians to translate cell-free strategies for cardiac tissue repair into clinical practice.

Association between lipoprotein(a), fibrinogen and their combination with all-cause, cardiovascular disease and cancer-related mortality: findings from the NHANES.

BACKGROUND: There is evidence indicating that both lipoprotein(a) [Lp(a)] and fibrinogen (FIB) are associated with mortality, However, the impact of their combination on mortality has not been determined. Thus, the aim of this study was to examine the association between the combination of Lp(a) and FIB with all-cause and cause-specific mortality. METHODS: This prospective cohort study enrolled 4,730 participants from the third National Health and Nutrition Examination Survey. The exposure variables included Lp(a), FIB and their combination, while the outcome variables consisted of all-cause, cardiovascular disease (CVD) and cancer-related mortality. Multivariate COX regression, subgroup analysis, sensitivity analysis and restricted cubic spline (RCS) were used to investigate the association between Lp(a), FIB and their combination with all-cause, CVD and cancer-related mortality. RESULTS: Over a median follow-up period of 235 months, 2,668 individuals died, including 1,051 deaths attributed to CVD and 549 deaths due to cancer. Multivariate Cox regression analyses revealed independent associations between both Lp(a) and FIB with all-cause, CVD, and cancer-related mortality. Compared to participants in the 1st to 50th percentiles of both Lp(a) and FIB, those in the 90th to 100th percentiles exhibited multivariable adjusted HRs of 1.813 (95% CI: 1.419-2.317, P < 0.001), 2.147 (95% CI: 1.483-3.109, P < 0.001) and 2.355 (95% CI: 1.396, 3.973, P = 0.001) for all-cause, CVD and cancer-related mortality, respectively. Subgroup and sensitivity analyses did not substantially attenuate the association between the combination of high Lp(a) and high FIB with the risk of all-cause and CVD-related mortality. Additionally, the RCS analysis showed that the relationship between Lp(a) and the risk of all-cause and cancer-related mortality, as well as the relationship between FIB and the risk of cancer-related mortality, were linear (P for nonlinearity > 0.05). Conversely, the relationship between Lp(a) and the risk of CVD-related mortality, as well as the relationship between FIB and the risk of all-cause and CVD-related mortality, were nonlinear (P for nonlinearity < 0.05). CONCLUSIONS: High levels of Lp(a) and FIB together conferred a greater risk of mortality from all-cause, CVD and cancer.

Diabetic kidney disease as an independent predictor of long-term adverse outcomes in patients with coronary artery disease and diabetic mellitus.

Background: Diabetic kidney disease (DKD) had been proposed as a contributor in the pathogenesis of coronary artery disease (CAD). However, the relationship of DKD and the long-term adverse outcomes in patients with CAD after percutaneous coronary intervention (PCI) was still undiscovered. Methods: Approximately 892 patients with CAD enrolled from January 2012 to December 2016. The patients were divided into two groups, the DKD group (n = 341) and the None DKD group (n = 551). The primary outcome was major adverse cardiac events (MACE) after PCI. The average follow-up time was 1,897 ± 1,276 days. Results: Baseline data showed that some factors were significantly different between the two groups, including age, body mass index, gender (female), hypertension, smoking, stroke history, heart failure, duration of diabetic mellitus (DM), low-density lipoprotein cholesterol, urinary protein/creatinine ratio, serum creatinine, hemoglobin, platelet, antiplatelet, beta blocker, statin, antihypertensive drugs, and insulin (all p < 0.005). There were significant differences between the two groups in MACE, 40.3% vs. 52.2% (p = 0.001), and in cardiovascular death events and all-cause death events (5.6% vs. 20.5%, p < 0.001 and 4.4% vs. 13.5%, p < 0.001, respectively). In the DKD group, the risk of MACE was elevated to 141.9% [hazard ratio (HR) = 1.419, 95% confidence interval (CI): 1.164-1.730, p = 0.001] in the Cox univariable regression analyses; after adjusting co-variables, the Cox multivariable regression analyses demonstrated that DKD was an independent predictor for MACE (HR = 1.291, 95% CI: 1.027-1.624, p = 0.029) in patients with CAD after PCI, as well as in cardiovascular death events (HR = 2.148, 95% CI: 1.292-3.572, p = 0.003) and all-cause death events (HR = 2.229, 95% CI: 1.325-3.749, p = 0.003). Conclusion: This study suggests that DKD is an independent and novel predictor of long-term adverse outcomes in patients with CAD and DM who underwent PCI.

Phage-assisted evolution of compact Cas9 variants targeting a simple NNG PAM.

Compact Cas9 nucleases hold great promise for therapeutic applications. Although several compact Cas9 nucleases have been developed, many genomic loci still could not be edited due to a lack of protospacer adjacent motifs (PAMs). We previously developed a compact SlugCas9 recognizing an NNGG PAM. Here we demonstrate that SlugCas9 displays comparable activity to SpCas9. We developed a simple phage-assisted evolution to engineer SlugCas9 for unique PAM requirements. Interestingly, we generated a SlugCas9 variant (SlugCas9-NNG) that could recognize an NNG PAM, expanding the targeting scope. We further developed a SlugCas9-NNG-based adenine base editor and demonstrated that it could be delivered by a single adeno-associated virus to disrupt PCSK9 splice donor and splice acceptor. These genome editors greatly enhance our ability for in vivo genome editing.

The future for the therapeutics of abdominal aortic aneurysm: engineered nanoparticles drug delivery for abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease with a high mortality rate. Several screening and diagnostic methods have been developed for AAA early diagnosis. Open surgery and endovascular aortic repair (EVAR) are clinically available for patients who meet the indications for surgery. However, for non-surgical patients, limited drugs exist to inhibit or reverse the progression of aneurysms due to the complex pathogenesis and biological structure of AAA, failing to accumulate precisely on the lesion to achieve sufficient concentrations. The recently developed nanotechnology offers a new strategy to address this problem by developing drug-carrying nanoparticles with enhanced water solubility and targeting capacity, prolonged duration, and reduced side effects. Despite the rising popularity, limited literature is available to highlight the progression of the field. Herein, in this review, we first discuss the pathogenesis of AAA, the methods of diagnosis and treatment that have been applied clinically, followed by the review of research progressions of constructing different drug-loaded nanoparticles for AAA treatment using engineered nanoparticles. In addition, the feasibility of extracellular vesicles (EVs) and EVs-based nanotechnology for AAA treatment in recent years are highlighted, together with the future perspective. We hope this review will provide a clear picture for the scientists and clinicians to find a new solution for AAA clinical management.

Prognostic Nutritional Index as a Novel Predictor of Long-Term Prognosis in Patients with Coronary Artery Disease After Percutaneous Coronary Intervention.

BACKGROUND: The Prognostic Nutritional Index (PNI) has been reported to be correlated with long-term outcomes after gastrointestinal tumor surgery. However, to our knowledge, only a few studies have shown that the PNI is related to cardiovascular diseases. Therefore, we aimed to assess the association between the PNI and long-term outcomes in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). METHODS: This was retrospective observational study. A total of 3561 patients with CAD after PCI were retrospectively enrolled in the CORFCHD-ZZ study from January 2013 to December 2017. The patients (3519) were divided into three groups according to PNI tertiles: the first tertile (PNI < 47.12, n = 1173), the second tertile (47.12 ≤ PNI < 51.50, n = 1185), and the third tertile (PNI ≥ 51.50, n = 1161). The mean follow-up time was 37.59 ± 22.24 months. The primary endpoint long-term mortality, including all-cause mortality (ACM) and cardiac mortality (CM).Secondary endpoints were major adverse cardiovascular events (MACEs) and major adverse cardiovascular and cerebrovascular events (MACCEs). RESULT: In our study, the incidences of ACM in the first, second, and third tertiles were 3.8%, 1.8% and 1.4%, respectively (P < 0.001). The incidences of CM occurring in the first, second, and third tertiles were 1.7%, 3.1% and 2.1%, respectively (P < 0.001).There was statistically significant different in primary endpoints incidence. MACEs occurred in 139 patients (11.8%) in the first tertile, 121 patients(11.1%) in the second tertile and 123 patients(10.8%) in the third tertile(P = 0.691). MACCEs occurred in 183 patients (15.6%) in the first tertile, 174 patients(14.7%) in the second tertile and 160 patients(13.85%) in the third tertile(P = 0.463).There was no statistically significant different in secondary endpoints incidence. Kaplan-Meier analyses showed that elevated PNI was significantly related to long-term CM (log rank, P < 0.001) and long-term ACM (log-rank, P < 0.001). Cox regression analyses suggested that compared with the patients in the first tertile, the risk of ACM was decreased to 60.9% (HR = 0.609, 95% CI: 0.398-0.932, P = 0.029) in the second tertile and 40.3%(HR = 0.403, 95% CI: 0.279-0.766, P = 0.003) in the third tertile, while the risk of CM was decreased to 58.8%(HR = 0.588, 95% CI: 0.321-0.969, P = 0.038) in the second tertile and 46.6%(HR = 0.466, 95% CI: 0.250-0.870, P = 0.017) in the third tertile. Multivariate Cox regression analyses showed that the PNI was an independent predictor of long-term ACM and CM. CONCLUSION: Our finding shown that PNI is an independent predictor in CAD patients after PCI，the higher the PNI, the less occurring adverse event. Therefore，PNI may be an new biomarker to predict long-term outcome of CAD patients after PCI.

Exosomes as a messager to regulate the crosstalk between macrophages and cardiomyocytes under hypoxia conditions.

Recent studies have confirmed that cardiomyocyte-derived exosomes have many pivotal biological functions, like influencing the progress of coronary artery disease via modulating macrophage phenotypes. However, the mechanisms underlying the crosstalk between cardiomyocytes and macrophages have not been fully characterized. Hence, this study aimed to observe the interaction between cardiomyocytes under hypoxia and macrophages through exosome communication and further evaluate the ability of exosomes derived from cardiomyocytes cultured under hypoxic conditions (Hypo-Exo) to polarize macrophages, and the effect of alternatively activated macrophages (M2) on hypoxic cardiomyocytes. Our results revealed that hypoxia facilitated the production of transforming growth factor-beta (TGF-ß) in H9c2 cell-derived exosomes. Moreover, exosomes derived from cardiomyocytes cultured under normal conditions (Nor-Exo) and Hypo-Exo could induce RAW264.7 cells into classically activated macrophages (M1) and M2 macrophages respectively. Likewise, macrophage activation was induced by circulating exosomes isolated from normal human controls (hNor-Exo) or patients with acute myocardial infarction (hAMI-Exo). Thus, our findings support that the profiles of hAMI-Exo have been changed, which could regulate the polarization of macrophages and subsequently the polarized M2 macrophages reduced the apoptosis of cardiomyocytes in return. Based on our findings, we speculate that exosomes have emerged as important inflammatory response modulators regulating cardiac oxidative stress injury.

Alkaline phosphatase-to-albumin ratio as a novel predictor of long-term adverse outcomes in coronary artery disease patients who underwent PCI.

BACKGROUND: Alkaline phosphatase (ALP) and albumin (ALB) have been shown to be associated with coronary artery disease (CAD), and it has been reported that alkaline phosphatase-to-albumin ratio (AAR) is associated with the liver damage and poorer prognosis of patients with digestive system malignancy. Moreover, several previous studies showed that there was a higher incidence of malignancy in CAD patients. However, to our knowledge, the relationship between AAR and long-term adverse outcomes in CAD patients after undergoing percutaneous coronary intervention (PCI) has not been investigated. Therefore, we aim to access the relation between AAR and long-term adverse outcomes in post-PCI patients with CAD. METHODS: A total of 3378 post-PCI patients with CAD were enrolled in the retrospective Clinical Outcomes and Risk Factors of Patients with Coronary Heart Disease after PCI (CORFCHD-ZZ) study from January 2013 to December 2017. The median duration of follow-up was 37.59 ± 22.24 months. The primary end point was long-term mortality including all-cause mortality (ACM) and cardiac mortality (CM). The secondary end points were major adverse cardiac events (MACEs) and major adverse cardiac and cerebrovascular events (MACCEs). RESULTS: Kaplan-Meier analyses showed that an increased AAR was positively correlated with incidences of long-term ACM (log-rank, P=0.014), CM (log-rank, P=0.011), MACEs (log-rank, P=0.013) and MACCEs (log-rank, P=0.006). Multivariate Cox regression analyses showed that the elevated AAR was an independent predictor of long-term ACM (adjusted HR = 1.488 [1.031-2.149], P=0.034), CM (adjusted HR = 1.837 [1.141-2.959], P=0.012), MACEs (adjusted HR = 1.257 [1.018-1.551], P=0.033) and MACCEs (adjusted HR = 1.237 [1.029-1.486], P=0.024). CONCLUSION: An elevated AAR is a novel independent predictor of long-term adverse outcomes in CAD patients following PCI.

New Insights and Novel Therapeutic Potentials for Macrophages in Myocardial Infarction.

Cardiovascular disease (CVD) has long been the leading cause of death worldwide, and myocardial infarction (MI) accounts for the greatest proportion of CVD. Recent research has revealed that inflammation plays a major role in the pathogenesis of CVD and other manifestations of atherosclerosis. Overwhelming evidence supports the view that macrophages, as the basic cell component of the innate immune system, play a pivotal role in atherosclerosis initiation and progression. Limited but indispensable resident macrophages have been detected in the healthy heart; however, the number of cardiac macrophages significantly increases during cardiac injury. In the early period of initial cardiac damage (e.g., MI), numerous classically activated macrophages (M1) originating from the bone marrow and spleen are rapidly recruited to damaged sites, where they are responsible for cardiac remodeling. After the inflammatory stage, the macrophages shift toward an alternatively activated phenotype (M2) that promotes cardiac repair. In addition, extensive studies have shown the therapeutic potential of macrophages as targets, especially for emerging nanoparticle-mediated drug delivery systems. In the present review, we focused on the role of macrophages in the development and progression of MI, factors regulating macrophage activation and function, and the therapeutic potential of macrophages in MI.

Circulating exosomes repair endothelial cell damage by delivering miR-193a-5p.

Circulating exosomes delivering microRNAs are involved in the occurrence and development of cardiovascular diseases. How are the circulating exosomes involved in the repair of endothelial injury in acute myocardial infarction (AMI) convalescence (3-7 days) was still not clear. In this study, circulating exosomes from AMI patients (AMI-Exo) and healthy controls (Normal-Exo) were extracted. In vitro and in vivo, our study showed that circulating exosomes protected endothelial cells (HUVECs) from oxidative stress damage; meanwhile, Normal-Exo showed better protective effects. Through the application of related inhibitors, we found that circulating exosomes shuttled between HUVECs via dynamin. Microarry analysis and qRT-PCR of circulating exosomes showed higher expression of miR-193a-5p in Normal-Exo. Our study showed that miR-193a-5p was the key factor on protecting endothelial cells in vitro and in vivo. Bioinformatics analyses found that activin A receptor type I (ACVR1) was the potential downstream target of miR-193a-5p, which was confirmed by ACVR1 expression and dual-luciferase report. Inhibitor of ACVR1 showed similar protective effects as miR-193a-5p. While overexpression of ACVR1 could attenuate protective effects of miR-193a-5p. To sum up, these findings suggest that circulating exosomes could shuttle between cells through dynamin and deliver miR-193a-5p to protect endothelial cells from oxidative stress damage via ACVR1.

Circulating tumor cells exit circulation while maintaining multicellularity, augmenting metastatic potential.

Metastasis accounts for the majority of all cancer deaths, yet the process remains poorly understood. A pivotal step in the metastasis process is the exiting of tumor cells from the circulation, a process known as extravasation. However, it is unclear how tumor cells extravasate and whether multicellular clusters of tumor cells possess the ability to exit as a whole or must first disassociate. In this study, we use in vivo zebrafish and mouse models to elucidate the mechanism tumor cells use to extravasate. We found that circulating tumor cells exit the circulation using the recently identified extravasation mechanism, angiopellosis, and do so as both clusters and individual cells. We further show that when melanoma and cervical cancer cells utilize this extravasation method to exit as clusters, they exhibit an increased ability to form tumors at distant sites through the expression of unique genetic profiles. Collectively, we present a new model for tumor cell extravasation of both individual and multicellular circulating tumor cells.This article has an associated First Person interview with the first author of the paper.

IL33 attenuates ventricular remodeling after myocardial infarction through inducing alternatively activated macrophages ethical standards statement.

Interleukin 33 (IL33) has been found to be cardioprotective on various cardiovascular pathologies. However, it is not clear whether IL33 may inhibit myocardial infarction-related ventricular remodeling through inducing macrophage polarization. The objective of present study is to assess whether IL33 can improve ventricular remodeling after myocardial infarction by inducing macrophage polarization. In this study, the direct influence of IL33 on the polarization of macrophages and its mechanism in vitro were investigated. The potential protective effects of IL33 on acute and chronic myocardial infarction (MI) in vivo as well as its underlying mechanism through macrophage polarization were also determined. We found that IL33 significantly enhanced M2 macrophage and decreased the proportion of M1 macrophage. Importantly, IL33 induced M2 macrophage polarization by activating the JAK/STAT signaling pathway. In vivo, IL33 weaken the inflammatory level and myocardial apoptosis after MI and improved the systolic and diastolic function of the heart. Furthermore, IL33 significantly reduced infarct area and prevented the progression of fibrosis by inducing M2 macrophage polarization. The protective effects of IL33 were suppressed by JAK/STAT signaling pathway inhibitor. Our findings highlighted that IL33 not only reduced the early inflammatory response and inhibited myocardial apoptosis, but also increased the number of M2 macrophage in the infarcted area, significantly reduced infarct area and prevented the progression of fibrosis by activating JAK/STAT pathway. Therefore, IL33 may be a novel cardiac protective cytokine for myocardial infarction.

microRNA-21-5p dysregulation in exosomes derived from heart failure patients impairs regenerative potential.

Exosomes, as functional paracrine units of therapeutic cells, can partially reproduce the reparative properties of their parental cells. The constitution of exosomes, as well as their biological activity, largely depends on the cells that secrete them. We isolated exosomes from explant-derived cardiac stromal cells from patients with heart failure (FEXO) or from normal donor hearts (NEXO) and compared their regenerative activities in vitro and in vivo. Patients in the FEXO group exhibited an impaired ability to promote endothelial tube formation and cardiomyocyte proliferation in vitro. Intramyocardial injection of NEXO resulted in structural and functional improvements in a murine model of acute myocardial infarction. In contrast, FEXO therapy exacerbated cardiac function and left ventricular remodeling. microRNA array and PCR analysis revealed dysregulation of miR-21-5p in FEXO. Restoring miR-21-5p expression rescued FEXO's reparative function, whereas blunting miR-21-5p expression in NEXO diminished its therapeutic benefits. Further mechanistic studies revealed that miR-21-5p augmented Akt kinase activity through the inhibition of phosphatase and tensin homolog. Taken together, the heart failure pathological condition altered the miR cargos of cardiac-derived exosomes and impaired their regenerative activities. miR-21-5p contributes to exosome-mediated heart repair by enhancing angiogenesis and cardiomyocyte survival through the phosphatase and tensin homolog/Akt pathway.

NIPAM-based Microgel Microenvironment Regulates the Therapeutic Function of Cardiac Stromal Cells.

To tune the chemical, physical, and mechanical microenvironment for cardiac stromal cells to treat acute myocardial infarction (MI), we prepared a series of thermally responsive microgels with different surface charges (positive, negative, and neutral) and different degrees of hydrophilicity, as well as functional groups (carboxyl, hydroxyl, amino, and methyl). These microgels were used as injectable hydrogels to create an optimized microenvironment for cardiac stromal cells (CSCs). Our results indicated that a hydrophilic and negatively charged microenvironment created from poly( N-isopropylacrylamide- co-itaconic acid) was favorable for maintaining high viability of CSCs, promoting CSC proliferation and facilitating the formation of CSC spheroids. A large number of growth factors, such as vascular endothelial growth factor (VEGF), insulin-like growth factor I (IGF-1), and stromal-derived factor-1 (SDF-1) were released from the spheroids, promoting neonatal rat cardiomyocyte activation and survival. After injecting the poly( N-isopropylacrylamide- co-itaconic acid) microgel into mice, we examined their acute inflammation and T-cell immune reactions. The microgel itself did not elicit obvious immune response. We then injected the same microgel-encapsulated with CSCs into MI mice. The result revealed the treatment-promoted MI heart repair through angiogenesis and inhibition of apoptosis with an improved cell retention rate. This study will open a door for tailoring poly( N-isopropylacrylamide)-based microgel as a delivery vehicle for CSC therapy.

Cardiac Stem Cell Patch Integrated with Microengineered Blood Vessels Promotes Cardiomyocyte Proliferation and Neovascularization after Acute Myocardial Infarction.

Cardiac stem cell (CSC) therapy has shown preclinical and clinical evidence for ischemic heart repair but is limited by low cellular engraftment and survival after transplantation. Previous versions of the cardiac patch strategy improve stem cell engraftment and encourage repair of cardiac tissue. However, cardiac patches that can enhance cardiomyogenesis and angiogenesis at the injured site remain elusive. Therapies that target cardiomyocyte proliferation and new blood vessel formation hold great potential for the protection against acute myocardial infarction (MI). Here, we report a new strategy for creating a vascularized cardiac patch in a facile and modular fashion by leveraging microfluidic hydrodynamic focusing to construct the biomimetic microvessels (BMVs) that include human umbilical vein endothelial cells (HUVECs) lining the luminal surface and then encapsulating the BMVs in a fibrin gel spiked with human CSCs. We show that the endothelialized BMVs mimicked the natural architecture and function of capillaries and that the resultant vascularized cardiac patch (BMV-CSC patch) exhibited equivalent release of paracrine factors compared to those of coculture of genuine human CSCs and HUVECs after 7 days of in vitro culture. In a rat model of acute MI, the BMV-CSC patch therapy induced profound mitotic activities of cardiomyocytes in the peri-infarct region 4 weeks post-treatment. A significant increase in myocardial capillary density was noted in the infarcted hearts that received BMV-CSC patch treatment compared to the infarcted hearts treated with conventional CSC patches. The striking therapeutic benefits and the fast and facile fabrication of the BMV-CSC patch make it promising for practical applications. Our findings suggest that the BMV-CSC patch strategy may open up new possibilities for the treatment of ischemic heart injury.

Targeted repair of heart injury by stem cells fused with platelet nanovesicles.

Stem cell transplantation, as used clinically, suffers from low retention and engraftment of the transplanted cells. Inspired by the ability of platelets to recruit stem cells to sites of injury on blood vessels, we hypothesized that platelets might enhance the vascular delivery of cardiac stem cells (CSCs) to sites of myocardial infarction injury. Here, we show that CSCs with platelet nanovesicles fused onto their surface membranes express platelet surface markers that are associated with platelet adhesion to injury sites. We also find that the modified CSCs selectively bind collagen-coated surfaces and endothelium-denuded rat aortas, and that in rat and porcine models of acute myocardial infarction the modified CSCs increase retention in the heart and reduce infarct size. Platelet-nanovesicle-fused CSCs thus possess the natural targeting and repairing ability of their parental cell types. This stem cell manipulation approach is fast, straightforward and safe, does not require genetic alteration of the cells, and should be generalizable to multiple cell types.

Concise Review: Is Cardiac Cell Therapy Dead? Embarrassing Trial Outcomes and New Directions for the Future.

Stem cell therapy is a promising strategy for tissue regeneration. The therapeutic benefits of cell therapy are mediated by both direct and indirect mechanisms. However, the application of stem cell therapy in the clinic is hampered by several limitations. This concise review provides a brief introduction into stem cell therapies for ischemic heart disease. It summarizes cell-based and cell-free paradigms, their limitations, and the benefits of using them to target disease. Stem Cells Translational Medicine 2018;7:354-359.

Therapeutic benefits of CD90-negative cardiac stromal cells in rats with a 30-day chronic infarct.

Cardiac stromal cells (CSCs) can be derived from explant cultures, and a subgroup of these cells is viewed as cardiac mesenchymal stem cells due to their expression of CD90. Here, we sought to determine the therapeutic potential of CD90-positive and CD90-negative CSCs in a rat model of chronic myocardial infarction. We obtain CD90-positive and CD90-negative fractions of CSCs from rat myocardial tissue explant cultures by magnetically activated cell sorting. In vitro, CD90-negative CSCs outperform CD90-positive CSCs in tube formation and cardiomyocyte functional assays. In rats with a 30-day infarct, injection of CD90-negative CSCs augments cardiac function in the infarct in a way superior to that from CD90-positive CSCs and unsorted CSCs. Histological analysis revealed that CD90-negative CSCs increase vascularization in the infarct. Our results suggest that CD90-negative CSCs could be a development candidate as a new cell therapy product for chronic myocardial infarction.

Heart Repair Using Nanogel-Encapsulated Human Cardiac Stem Cells in Mice and Pigs with Myocardial Infarction.

Stem cell transplantation is currently implemented clinically but is limited by low retention and engraftment of transplanted cells and the adverse effects of inflammation and immunoreaction when allogeneic or xenogeneic cells are used. Here, we demonstrate the safety and efficacy of encapsulating human cardiac stem cells (hCSCs) in thermosensitive poly(N-isopropylacrylamine-co-acrylic acid) or P(NIPAM-AA) nanogel in mouse and pig models of myocardial infarction (MI). Unlike xenogeneic hCSCs injected in saline, injection of nanogel-encapsulated hCSCs does not elicit systemic inflammation or local T cell infiltrations in immunocompetent mice. In mice and pigs with acute MI, injection of encapsulated hCSCs preserves cardiac function and reduces scar sizes, whereas injection of hCSCs in saline has an adverse effect on heart healing. In conclusion, thermosensitive nanogels can be used as a stem cell carrier: the porous and convoluted inner structure allows nutrient, oxygen, and secretion diffusion but can prevent the stem cells from being attacked by immune cells.

Safety and Efficacy of Allogeneic Lung Spheroid Cells in a Mismatched Rat Model of Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis is a devastating interstitial lung disease characterized by the relentless deposition of extracellular matrix causing lung distortions and dysfunctions. The prognosis after detection is merely 3-5 years and the only two Food and Drug Administration-approved drugs treat the symptoms, not the disease, and have numerous side effects. Stem cell therapy is a promising treatment strategy for pulmonary fibrosis. Current animal and clinical studies focus on the use of adipose or bone marrow-derived mesenchymal stem cells. We, instead, have established adult lung spheroid cells (LSCs) as an intrinsic source of therapeutic lung stem cells. In the present study, we compared the efficacy and safety of syngeneic and allogeneic LSCs in immuno-competent rats with bleomycin-induced pulmonary inflammation in an effort to mitigate fibrosis development. We found that infusion of allogeneic LSCs reduces the progression of inflammation and fibrotic manifestation and preserves epithelial and endothelial health without eliciting significant immune rejection. Our study sheds light on potential future developments of LSCs as an allogeneic cell therapy for humans with pulmonary fibrosis. Stem Cells Translational Medicine 2017;9:1905-1916.