HO-1 modified mesenchymal stem cells modulate MMPs/TIMPs system and adverse remodeling in infarcted myocardium

The DPP-IV inhibitor saxagliptin promotes the migration and invasion of papillary thyroid carcinoma cells via the NRF2/HO1 pathway

Dipeptidyl peptidase-IV (DPP-IV) inhibitors are used to control blood glucose levels in patients with type 2 diabetes. However, the influence of DPP-IV inhibitors on malignant tumors remains unknown. The present study aimed to investigate the effect of the DPP-IV inhibitor saxagliptin on thyroid carcinoma cells. Transwell assays and a nude mouse lung metastasis model were used to evaluate the invasion and metastasis of thyroid carcinoma cells. Western blotting was used to determine the protein levels of migration and invasion-related molecules. We tested the expression and distribution of nuclear factor, erythroid 2 like 2 (NRF2) in thyroid carcinoma cells with and without saxagliptin. Furthermore, we silenced NRF2 and observed saxagliptin's effect on migration and invasion. Quantitative real-time reverse transcription PCR (qRT-PCR) and western blotting were then used to measure the expression of NFR2's downstream molecules (heme oxygenase 1 (HO1), matrix metalloproteinase 2 (MMP2), and vascular endothelial growth factor (VEGF)). A luciferase reporter assay was used to validate whether NRF2 could regulate the transcriptional activity of the HO1 promoter. Saxagliptin enhanced the migratory and invasive ability of thyroid carcinoma cells. MMP2 and VEGF levels were also elevated by saxagliptin treatment. We found that saxagliptin treatment increases the nuclear and cytoplasmic accumulation NRF2. Silencing NRF2 abolished the effect of saxagliptin on migration and invasion. Accordingly, NRF2 silencing downregulated HO1, MMP2, and VEGF levels. The luciferase assay showed that NRF2 activated transcription from the HO1 promoter. Saxagliptin could promote this transcriptional activity by upregulating NRF2. Saxagliptin enhanced the migratory and invasive ability of human thyroid carcinoma cells, as well as the expression of MMP2 and VEGF, by activating the NRF2/HO1 pathway.

[Research progress in mesenchymal stem cells modified by Heme oxygenase 1]

Objective

To review the literature reports on research progress of Heme oxygenase 1 (HO-1) modified mesenchymal stem cells (MSCs).

Methods

The significance, effects, and related mechanism of HO-1 modification of MSCs were summarized by consulting the related literatures and reports of HO-1 modification of MSCs.

Results

HO-1 modification of MSCs has important research value. It can effectively enhance the anti-oxidative stress and anti-apoptotic properties of MSCs in complex internal environment after transplantation into vivo. It can also effectively enhance the immune regulation function of MSCs. It can improve the anti-injury, repair, and immune regulation effect of MSCs in various disease models and research fields.

Conclusion

The basic research of HO-1 modified MSCs has made remarkable progress, which is expected to be applied in clinical trials and provide theoretical basis and reference value for stem cell therapy.

Improved therapeutic potential of MSCs by genetic modification

Mesenchymal stem cells (MSCs), well-studied adult stem cells in various tissues, possess multi-lineage differentiation potential and anti-inflammatory properties. MSCs have been approved to regenerate lineage-specific cells to replace injured cells in tissues. MSCs are approved to treat inflammatory diseases. With the discovery of genes important for the repair of damaged tissues, MSCs genetically modified by such genes hold improved therapeutic potential. In this review, we summarised the uses of genetically modified MSCs to treat different diseases, including bone diseases, cardiovascular diseases, autoimmune diseases, central nervous system disorders, and cancer. To better understand the exact role of genetically modified MSCs, key mechanisms determining, which genes are selected to be used for modifying MSCs and improvements in post-genetic modification are discussed. Therapeutic benefits enhanced by genetic modifications are to be documented by further clinical studies.

Smell of cells: Volatile profiling of stem- and non-stem cell proliferation

Bacterial and cell cultures are known to emit a large number of volatile organic compounds (VOCs). Conventional biochemical methods are often destructive, time-consuming and expensive. In contrast, VOC analysis of headspace over cultures may offer a non-destructive alternative for the monitoring of cell proliferation and metabolism. VOC profiles from cultures of murine pluripotent stem cells and fibroblasts were assessed every 24 h for 3 days. Pure cell media were measured as parallel controls. VOC analysis was highly standardized with respect to time of measurement and phases of cell growth. Cultures were grown in custom-made inert boxes. In order to determine the effects of fresh media supply on VOC emissions, both cell types were cultured with and without daily media exchange. VOCs from headspace were preconcentrated by means of needle trap micro-extraction and analysed by gas chromatography-mass spectrometry (GC-MS). Murine pluripotent stem cells emitted increasing concentrations of thiirane and methyl-methoxy-hydroxy-methyl-amine (MMHA). Substance concentration correlated with cell numbers. Murine fibroblasts did not emit thiirane or MMHA. Concentrations of aldehydes, especially benzaldehyde, were lower in both cell cultures than in pure media samples. Daily media exchange resulted in higher cell numbers, but had no major effects on VOC concentrations emitted from the cells. Investigation and monitoring of volatile substances such as thiirane and MMHA may enhance the understanding of stem cell properties and lead to a destruction-free characterization of pluripotent stem cells.

Arctigenin exerts protective effects against myocardial infarction via regulation of iNOS, COX‑2, ERK1/2 and HO‑1 in rats

The present study aimed to determine the protective effects of arctigenin against myocardial infarction (MI), and its effects on oxidative stress and inflammation in rats. Left anterior coronary arteries of Sprague‑Dawley rats were ligated, in order to generate an acute MI (AMI) model. Arctigenin was administered to AMI rats at 0, 50, 100 or 200 µmol/kg. Western blotting and ELISAs were performed to analyze protein expression and enzyme activity. Arctigenin was demonstrated to effectively inhibit the levels of alanine transaminase, creatine kinase‑MB and lactate dehydrogenase, and to reduce infarct size in AMI rats. In addition, the activity levels of malondialdehyde, interleukin (IL)‑1β and IL‑6 were significantly suppressed, and the levels of glutathione peroxidase, catalase and superoxide dismutase were significantly increased by arctigenin treatment. Arctigenin treatment also suppressed the protein expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX‑2) and heme oxygenase 1 (HO‑1), and increased the protein expression levels of phosphorylated‑extracellular signal‑regulated kinase 1/2 (p‑ERK1/2) in AMI rats. Overall, the results of the present study suggest that arctigenin may inhibit MI, and exhibits antioxidative and anti‑inflammatory effects through regulation of the iNOS, COX‑2, ERK1/2 and HO‑1 pathways in a rat model of AMI.

Costunolide increases osteoblast differentiation via ATF4-dependent HO-1 expression in C3H10T1/2 cells

AIMS

Costunolide is a sesquiterpene lactones used in many herbal medicines, with well-established anti-inflammatory and anti-oxidant functions modulating endoplasmic reticulum (ER) stress pathways, and which promotes the expression of anti-oxidant genes. The aim of this study is to investigate whether costunolide is involved in osteoblast differentiation and, determine the mechanisms of differentiation in mesenchymal stem cells.

MAIN METHODS

The cytotoxicity of costunolide was identified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mRNA and protein expression levels of osteogenic genes were determined by RT-PCR and Western blot analysis. Alkaline phosphate (ALP) staining and Alizarin red S (ARS) staining were performed to evaluate ALP activity and matrix mineralization. Transcriptional activity was detected using a luciferase reporter assay.

KEY FINDINGS

In this study, we determined that costunolide increased the expression of distal-less homeobox 5 (Dlx5), runt-related transcription factor 2 (Runx2), ALP, and osteocalcin (OC) in C3H10T 1/2 cells. Furthermore, costunolide increased ALP activity and matrix mineralization. Interestingly, costunolide increased ER stress by Bip, activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP). However, it did not exert effects on expression of activating transcription factor 6 (ATF6). ATF4 activation has a protective role in oxidative stress, and its transcription induces anti-oxidant genes in cells. Heme oxygenase-1 (HO-1) is a major anti-oxidant enzyme, and is regulated by ATF4. We showed that costunolide treatment increased HO-1 expression. Furthermore, the HO-1 inhibitor, Sn(IV) Protoporphyrin IX dichloride (SnPP) was blocked costunolide-induced Runx2 expression.

SIGNIFICANCE

Our results revealed that costunolide-induced osteoblast differentiation is regulated by ATF4-dependent HO-1 expression.

Rebuilding the Damaged Heart: Mesenchymal Stem Cells, Cell-Based Therapy, and Engineered Heart Tissue

Mesenchymal stem cells (MSCs) are broadly distributed cells that retain postnatal capacity for self-renewal and multilineage differentiation. MSCs evade immune detection, secrete an array of anti-inflammatory and anti-fibrotic mediators, and very importantly activate resident precursors. These properties form the basis for the strategy of clinical application of cell-based therapeutics for inflammatory and fibrotic conditions. In cardiovascular medicine, administration of autologous or allogeneic MSCs in patients with ischemic and nonischemic cardiomyopathy holds significant promise. Numerous preclinical studies of ischemic and nonischemic cardiomyopathy employing MSC-based therapy have demonstrated that the properties of reducing fibrosis, stimulating angiogenesis, and cardiomyogenesis have led to improvements in the structure and function of remodeled ventricles. Further attempts have been made to augment MSCs' effects through genetic modification and cell preconditioning. Progression of MSC therapy to early clinical trials has supported their role in improving cardiac structure and function, functional capacity, and patient quality of life. Emerging data have supported larger clinical trials that have been either completed or are currently underway. Mechanistically, MSC therapy is thought to benefit the heart by stimulating innate anti-fibrotic and regenerative responses. The mechanisms of action involve paracrine signaling, cell-cell interactions, and fusion with resident cells. Trans-differentiation of MSCs to bona fide cardiomyocytes and coronary vessels is also thought to occur, although at a nonphysiological level. Recently, MSC-based tissue engineering for cardiovascular disease has been examined with quite encouraging results. This review discusses MSCs from their basic biological characteristics to their role as a promising therapeutic strategy for clinical cardiovascular disease.

Health effects of carbon-containing particulate matter: focus on sources and recent research program results

Air pollution is a complex mixture of gas-, vapor-, and particulate-phase materials comprised of inorganic and organic species. Many of these components have been associated with adverse health effects in epidemiological and toxicological studies, including a broad spectrum of carbonaceous atmospheric components. This paper reviews recent literature on the health impacts of organic aerosols, with a focus on specific sources of organic material; it is not intended to be a comprehensive review of all the available literature. Specific emission sources reviewed include engine emissions, wood/biomass combustion emissions, biogenic emissions and secondary organic aerosol (SOA), resuspended road dust, tire and brake wear, and cooking emissions. In addition, recent findings from large toxicological and epidemiological research programs are reviewed in the context of organic PM, including SPHERES, NPACT, NERC, ACES, and TERESA. A review of the extant literature suggests that there are clear health impacts from emissions containing carbon-containing PM, but difficulty remains in apportioning responses to certain groupings of carbonaceous materials, such as organic and elemental carbon, condensed and gas phases, and primary and secondary material. More focused epidemiological and toxicological studies, including increased characterization of organic materials, would increase understanding of this issue.

Use of mesenchymal stem cells for therapy of cardiac disease

Despite substantial clinical advances over the past 65 years, cardiovascular disease remains the leading cause of death in America. The past 15 years has witnessed major basic and translational interest in the use of stem and precursor cells as a therapeutic agent for chronically injured organs. Among the cell types under investigation, adult mesenchymal stem cells are widely studied, and in early stage, clinical studies show promise for repair and regeneration of cardiac tissues. The ability of mesenchymal stem cells to differentiate into mesoderm- and nonmesoderm-derived tissues, their immunomodulatory effects, their availability, and their key role in maintaining and replenishing endogenous stem cell niches have rendered them one of the most heavily investigated and clinically tested type of stem cell. Accumulating data from preclinical and early phase clinical trials document their safety when delivered as either autologous or allogeneic forms in a range of cardiovascular diseases, but also importantly define parameters of clinical efficacy that justify further investigation in larger clinical trials. Here, we review the biology of mesenchymal stem cells, their interaction with endogenous molecular and cellular pathways, and their modulation of immune responses. Additionally, we discuss factors that enhance their proliferative and regenerative ability and factors that may hinder their effectiveness in the clinical setting.

The PPARγ agonist, rosiglitazone, attenuates airway inflammation and remodeling via heme oxygenase-1 in murine model of asthma

AIM

Rosiglitazone is one of the specific PPARγ agonists showing potential therapeutic effects in asthma. Though PPARγ activation was considered protective in inhibiting airway inflammation and remodeling in asthma, the specific mechanisms are still unclear. This study was aimed to investigate whether heme oxygenase-1 (HO-1) related pathways were involved in rosiglitazone-activated PPARγ signaling in asthma treatment.

METHODS

Asthma was induced in mice by multiple exposures to ovalbumin (OVA) in 8 weeks. Prior to every OVA challenge, the mice received rosiglitazone (5 mg/kg, p.o.). After the mice were sacrificed, the bronchoalveolar lavage fluid (BALF), blood samples and lungs were collected for analyses. The activities of HO-1, MMP-2 and MMP-9 in airway tissue were assessed, and the expression of PPARγ, HO-1 and p21 proteins was also examined.

RESULTS

Rosiglitazone administration significantly attenuated airway inflammation and remodeling in mice with OVA-induced asthma, which were evidenced by decreased counts of total cells, eosinophils and neutrophils, and decreased levels of IL-5 and IL-13 in BALF, and by decreased airway smooth muscle layer thickness and reduced airway collagen deposition. Furthermore, rosiglitazone administration significantly increased PPARγ, HO-1 and p21 expression and HO-1 activity, decreased MMP-2 and MMP-9 activities in airway tissue. All the therapeutic effects of rosiglitazone were significantly impaired by co-administration of the HO-1 inhibitor ZnPP.

CONCLUSION

Rosiglitazone effectively attenuates airway inflammation and remodeling in OVA-induced asthma of mice by activating PPARγ/HO-1 signaling pathway.

Cardiac cell proliferation assessed by EdU, a novel analysis of cardiac regeneration

Emerging evidence suggests that mammalian hearts maintain the capacity for cardiac regeneration. Rapid and sensitive identification of cardiac cellular proliferation is prerequisite for understanding the underlying mechanisms and strategies of cardiac regeneration. The following immunologically related markers of cardiac cells were analyzed: cardiac transcription factors Nkx2.5 and Gata 4; specific marker of cardiomyocytes TnT; endothelial cell marker CD31; vascular smooth muscle marker smooth muscle myosin IgG; cardiac resident stem cells markers IsL1, Tbx18, and Wt1. Markers were co-localized in cardiac tissues of embryonic, neonatal, adult, and pathological samples by 5-ethynyl-2'-deoxyuridine (EdU) staining. EdU was also used to label isolated neonatal cardiomyocytes in vitro. EdU robustly labeled proliferating cells in vitro and in vivo, co-immunostaining with different cardiac cells markers. EdU can rapidly and sensitively label proliferating cardiac cells in developmental and pathological states. Cardiac cell proliferation assessed by EdU is a novel analytical tool for investigating the mechanism and strategies of cardiac regeneration in response to injury.

Heme oxygenase-1: an emerging therapeutic target to curb cardiac pathology

Activation of heme oxygenase-1 (HO-1), a heme-degrading enzyme responsive to a wide range of cellular stress, is traditionally considered to convey adaptive responses to oxidative stress, inflammation and vasoconstriction. These diversified effects are achieved through the degradation of heme to carbon monoxide (CO), biliverdin (which is rapidly converted to bilirubin by biliverdin reductase) and ferric iron. Recent findings have added antiproliferative and angiogenic effects to the list of HO-1/CO actions. HO-1 along with its reaction products bilirubin and CO are protective against ischemia-induced injury (myocardial infarction, ischemia-reperfusion (IR)-injury and post-infarct structural remodelling). Moreover, HO-1, and CO in particular, possess acute antihypertensive effects. As opposed to these curative potentials, the long-believed protective effect of HO-1 in cardiac remodelling in response to pressure overload and type 2 diabetes mellitus (DM) has been questioned by recent work. These challenges, coupled with emerging regulatory mechanisms, motivate further in-depth studies to help understand untapped layers of HO-1 regulation and action. The outcomes of these efforts may shed new light on critical mechanisms that could be used to harness the protective potential of this enzyme for the therapeutic benefit of patients suffering from such highly prevalent cardiovascular disorders.

The influence of autologous bone marrow stem cell transplantation on matrix metalloproteinases in patients treated for acute ST-elevation myocardial infarction

Background. Matrix metalloproteinase-9 (MMP-9), regulated by tissue inhibitor of metalloproteinase-9 (TIMP-1) and the extracellular matrix metalloproteinase inducer (EMMPRIN), contributes to plaque instability. Autologous stem cells from bone marrow (mBMC) treatment are suggested to reduce myocardial damage; however, limited data exists on the influence of mBMC on MMPs. Aim. We investigated the influence of mBMC on circulating levels of MMP-9, TIMP-1, and EMMPRIN at different time points in patients included in the randomized Autologous Stem-Cell Transplantation in Acute Myocardial Infarction (ASTAMI) trial (n = 100). Gene expression analyses were additionally performed. Results. After 2-3 weeks we observed a more pronounced increase in MMP-9 levels in the mBMC group, compared to controls (P = 0.030), whereas EMMPRIN levels were reduced from baseline to 2-3 weeks and 3 months in both groups (P < 0.0001). Gene expression of both MMP-9 and EMMPRIN was reduced from baseline to 3 months. MMP-9 and EMMPRIN were significantly correlated to myocardial injury (CK: P = 0.005 and P < 0.001, resp.) and infarct size (SPECT: P = 0.018 and P = 0.008, resp.). Conclusion. The results indicate that the regulation of metalloproteinases is important during AMI, however, limited influenced by mBMC.

The role of Nrf2-mediated pathway in cardiac remodeling and heart failure

Heart failure (HF) is frequently the consequence of sustained, abnormal neurohormonal, and mechanical stress and remains a leading cause of death worldwide. The key pathophysiological process leading to HF is cardiac remodeling, a term referring to maladaptation to cardiac stress at the molecular, cellular, tissue, and organ levels. HF and many of the conditions that predispose one to HF are associated with oxidative stress. Increased generation of reactive oxygen species (ROS) in the heart can directly lead to increased necrosis and apoptosis of cardiomyocytes which subsequently induce cardiac remodeling and dysfunction. Nuclear factor-erythroid-2- (NF-E2-) related factor 2 (Nrf2) is a transcription factor that controls the basal and inducible expression of a battery of antioxidant genes and other cytoprotective phase II detoxifying enzymes that are ubiquitously expressed in the cardiovascular system. Emerging evidence has revealed that Nrf2 and its target genes are critical regulators of cardiovascular homeostasis via the suppression of oxidative stress, which is the key player in the development and progression of HF. The purpose of this review is to summarize evidence that activation of Nrf2 enhances endogenous antioxidant defenses and counteracts oxidative stress-associated cardiac remodeling and HF.

Role of heme oxygenase-1 in postnatal differentiation of stem cells: a possible cross-talk with microRNAs

SIGNIFICANCE

Heme oxygenase-1 (HO-1) converts heme to biliverdin, carbon monoxide, and ferrous ions, but its cellular functions are far beyond heme metabolism. HO-1 via heme removal and degradation products acts as a cytoprotective, anti-inflammatory, immunomodulatory, and proangiogenic protein, regulating also a cell cycle. Additionally, HO-1 can translocate to nucleus and regulate transcription factors, so it can also act independently of enzymatic function.

RECENT ADVANCES

Recently, a body of evidence has emerged indicating a role for HO-1 in postnatal differentiation of stem and progenitor cells. Maturation of satellite cells, skeletal myoblasts, adipocytes, and osteoclasts is inhibited by HO-1, whereas neurogenic differentiation and formation of cardiomyocytes perhaps can be enhanced. Moreover, HO-1 influences a lineage commitment in pluripotent stem cells and maturation of hematopoietic cells. It may play a role in development of osteoblasts, but descriptions of its exact effects are inconsistent.

CRITICAL ISSUES

In this review we discuss a role of HO-1 in cell differentiation, and possible HO-1-dependent signal transduction pathways. Among the potential mediators, we focused on microRNA (miRNA). These small, noncoding RNAs are critical for cell differentiation. Recently we have found that HO-1 not only influences expression of specific miRNAs but also regulates miRNA processing enzymes.

FUTURE DIRECTIONS

It seems that interplay between HO-1 and miRNAs may be important in regulating fates of stem and progenitor cells and needs further intensive studies.

Mechanisms of therapeutic activity of multipotent cells in heart diseases

Analysis of our findings and published reports on possible mechanisms of therapeutic activity of stem/progenitor cell transplantation in cardiovascular pathologies is presented.

The effects of α-pinene versus toluene-derived secondary organic aerosol exposure on the expression of markers associated with vascular disease

To investigate the toxicological effects of biogenic- versus anthropogenic-source secondary organic aerosol (SOA) on the cardiovascular system, the Secondary Particulate Health Effects Research program irradiation chamber was used to expose atherosclerotic apolipoprotein E null (Apo E-/-) mice to SOA from the oxidation of either α-pinene or toluene for 7 days. SOA atmospheres were produced to yield 250-300 μg/m(3) of particulate matter and ratios of 10:1:1 α-pinene:nitrogen oxide (NOx):ammonia (NH3); 10:1:1:1 α-pinene:NOx:NH3:sulfur dioxide (SO2) or 10:1:1 toluene:NOx:NH3; and 10:1:1:1 toluene:NOx:NH3:SO2. Resulting effects on the cardiovascular system were assessed by measurement of vascular lipid peroxidation (thiobarbituric acid reactive substance (TBARS)), as well as quantification of heme-oxygenase (HO)-1, endothelin (ET)-1, and matrix metalloproteinase (MMP)-9 mRNA expression for comparison to previous program exposure results. Consistent with similar previous studies, vascular TBARS were not increased significantly with any acute SOA exposure. However, vascular HO-1, MMP-9, and ET-1 observed in Apo E-/- mice exposed to α-pinene + NOx + NH3 + SO2 increased statistically, while α-pinene + NOx + NH3 exposure to either toluene + NOx + NH3 or toluene +NOx + NH3 + SO2 resulted in a decreased expression of these vascular factors. Such findings suggest that the specific chemistry created by the presence or absence of acidic components may be important in SOA-mediated toxicity in the cardiovascular system and/or progression of cardiovascular disease.

Exploring the role of soluble factors associated with immune regulatory properties of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are characterized as multipotent stromal cells with the capacity for both self-renewal and differentiation into mesodermal cell lineages. MSCs also have a fibroblast-like phenotype and can be isolated from several tissues. In recent years, researchers have found that MSCs secrete several soluble factors that exert immunosuppressive effects by modulating both innate (macrophages, dendritic and NK cells) and adaptive (B cells and CD4+ and CD8+ T cells) immune responses. This review summarizes the principal trophic factors that are related to immune regulation and secreted by MSCs under both autoimmune and inflammatory conditions. The understanding of mechanisms that regulate immunity in MSCs field is important for their future use as a novel cellular-based immunotherapy with clinical applications in several diseases.

Effects of intracoronary delivery of allogenic bone marrow-derived stem cells expressing heme oxygenase-1 on myocardial reperfusion injury

Heme oxygenase-1 (HO-1) decreases apoptosis, inflammation and oxidative stress. The aim of the study was to investigate the effects of intracoronary infusion of allogenic bone marrow cells (BMC) overexpressing HO-1 in the porcine model of myocardial infarction (MI). MI was produced by balloon occlusion of a coronary artery. BMC were transduced with adenoviruses encoding for HO-1 (HO-1 BMC) or GFP (GFP-BMC) genes. Prior to reperfusion animals received HO-1 BMC, control BMC (unmodified or GFP-BMC) or placebo. Left ventricular (LV) ejection fraction (EF), shortening fraction (SF), end-systolic and end-diastolic diameters (EDD, ESD) were assessed by echocardiography before, 30 minutes (min) and 14 days after reperfusion. BMC significantly improved LVEF and SF early (30 min) after reperfusion as well as after 14 days. Early after reperfusion HO-1 BMC were significantly more effective than control BMC, but after 14 days, there were no differences. There were no effect of cells on LV remodelling and diastolic function. Both HO-1 BMC and control BMC significantly reduced the infarct size vs. placebo (17.2 ± 2.7 and 18.8 ± 2.5, respectively, vs. 27.5 ± 5.1, p= 0.02) in histomorphometry. HO-1-positive donor BMC were detected in the infarct border area in pigs receiving HO-1-cells. No significant differences in expression of inflammatory genes (SDF-1, TNF-α, IL-6, miR21, miR29a and miR133a) in the myocardium were found. In conclusion, intracoronary delivery of allogeneic BMC immediately prior to reperfusion improved the LVEF and reduced the infarct size. HO-1 BMC were not superior to control cells after 14 days, however, produced faster recovery of LVEF. Transplanted cells survived in the peri-infarct zone.

Adenovirus-mediated expression of the HO-1 protein within MSCs decreased cytotoxicity and inhibited apoptosis induced by oxidative stresses

The capacity of mesenchymal stem cells (MSCs) to survive and engraft in the target tissue may lead to promising therapeutic effects. However, the fact that the majority of MSCs die during the first few days following transplantation complicates cell therapy. Hence, it is necessary to strengthen the stem cells to withstand the rigors of the microenvironment to improve the efficacy of cell therapy. In this study, we manipulated MSCs to express a cytoprotective factor, heme oxygenase-1 (HO-1), to address this issue. Full-length cDNA of human HO-1 was isolated and cloned into TOPO vector by TOPO cloning reaction. Then, the construct was ligated to gateway adapted adenovirus expression vector by LR recombination reaction. Afterwards, the recombinant virus expressing HO-1 was produced in appropriate mammalian cell line and used to infect MSCs. The HO-1 engineered MSCs were exposed to hypoxic and oxidative stress conditions followed by evaluation of the cells' viability and apoptosis. Transient expression of HO-1 was detected within MSCs. It was observed that HO-1 expression could protect MSCs against cell death and the apoptosis triggered by hypoxic and oxidative stress conditions. The MSCs-HO-1 retained their ability to differentiate into adipogenic, chondrogenic, or osteogenic lineages. These findings could be applied as a strategy for prevention of graft cell death in MSCs-based cell therapy and is a good demonstration of how an understanding of cellular stress responses can be used for practical applications.

Preconditioning approach in stem cell therapy for the treatment of infarcted heart

Nearly two decades of research in regenerative medicine have been focused on the development of stem cells as a therapeutic option for treatment of the ischemic heart. Given the ability of stem cells to regenerate the damaged tissue, stem-cell-based therapy is an ideal approach for cardiovascular disorders. Preclinical studies in experimental animal models and clinical trials to determine the safety and efficacy of stem cell therapy have produced encouraging results that promise angiomyogenic repair of the ischemically damaged heart. Despite these promising results, stem cell therapy is still confronted with issues ranging from uncertainty about the as-yet-undetermined "ideal" donor cell type to the nonoptimized cell delivery strategies to harness optimal clinical benefits. Moreover, these lacunae have significantly hampered the progress of the heart cell therapy approach from bench to bedside for routine clinical applications. Massive death of donor cells in the infarcted myocardium during acute phase postengraftment is one of the areas of prime concern, which immensely lowers the efficacy of the procedure. An overview of the published data relevant to stem cell therapy is provided here and the various strategies that have been adopted to develop and optimize the protocols to enhance donor stem cell survival posttransplantation are discussed, with special focus on the preconditioning approach.

Repair mechanisms of bone marrow mesenchymal stem cells in myocardial infarction

The prognosis of patients with myocardial infarction (MI) and resultant chronic heart failure remains extremely poor despite advances in optimal medical therapy and interventional procedures. Animal experiments and clinical trials using adult stem cell therapy following MI have shown a global improvement of myocardial function. Bone marrow-derived mesenchymal stem cells (MSCs) hold promise for cardiac repair following MI, due to their multilineage, self-renewal and proliferation potential. In addition, MSCs can be easily isolated, expanded in culture, and have immunoprivileged properties to the host tissue. Experimental studies and clinical trials have revealed that MSCs not only differentiate into cardiomyocytes and vascular cells, but also secrete amounts of growth factors and cytokines which may mediate endogenous regeneration via activation of resident cardiac stem cells and other stem cells, as well as induce neovascularization, anti-inflammation, anti-apoptosis, anti-remodelling and cardiac contractility in a paracrine manner. It has also been postulated that the anti-arrhythmic and cardiac nerve sprouting potential of MSCs may contribute to their beneficial effects in cardiac repair. Most molecular and cellular mechanisms involved in the MSC-based therapy after MI are still unclear at present. This article reviews the potential repair mechanisms of MSCs in the setting of MI.

Advances in mesenchymal stem cell research in sepsis

BACKGROUND

Sepsis remains a source of morbidity and mortality in the postoperative patient despite appropriate resuscitative and antimicrobial approaches. Recent research has focused upon additional interventions such as exogenous cell-based therapy. Mesenchymal stem cells (MSCs) exhibit multiple beneficial properties through their capacity for homing, attenuating the inflammatory response, modulating immune cells, and promoting tissue healing. Recent animal trials have provided evidence that MSCs may be useful therapeutic adjuncts.

MATERIALS AND METHODS

A directed search of recent medical literature was performed utilizing PubMed to examine the pathophysiology of sepsis, mechanisms of mesenchymal stem cell interaction with host cells, sepsis animal models, and recent trials utilizing stem cells in sepsis.

RESULTS

MSCs continue to show promise in the treatment of sepsis by their intrinsic ability to home to injured tissue, secrete paracrine signals to limit systemic and local inflammation, decrease apoptosis in threatened tissues, stimulate neoangiogenesis, activate resident stem cells, beneficially modulate immune cells, and exhibit direct antimicrobial activity. These effects are associated with reduced organ dysfunction and improved survival in animal models.

CONCLUSION

Research utilizing animal models of sepsis has provided a greater understanding of the beneficial properties of MSCs. Their capacity to home to sites of injury and use paracrine mechanisms to change the local environment to ultimately improve organ function and survival make MSCs attractive in the treatment of sepsis. Future studies are needed to further evaluate the complex interactions between MSCs and host tissues.

A central role of heme oxygenase-1 in cardiovascular protection

The intrinsic defense mechanisms of the body are critical in protecting tissues from injury in response to pathological stress. Heme oxygenase-1 (HO-1), a stress response protein, is induced in response to various pathological stimuli to serve a cytoprotective function. By degrading the oxidant heme and generating the antioxidant bilirubin and anti-inflammatory molecule carbon monoxide, HO-1 may protect cell from injury due to oxidative and pathological stress. Oxidative stress in the heart caused by ischemia and reperfusion leads to cardiomyocyte death and subsequent myocardial infarction. Vascular diseases including atherosclerosis, graft failure, and restenosis are all associated with reactive oxygen species-induced injury and inflammation. Given that cardiovascular disease is the leading cause of death worldwide, there is considerable interest in developing new strategies for preventing and treating cardiovascular disease. Since HO-1 is induced in the heart and blood vessels in response to various stresses, a role of HO-1 has been implicated in cardiovascular homeostasis. Numerous studies using pharmacological method or genetic approach have since demonstrated the cardiovascular protective function of HO-1. Importantly, a number of studies have associated human HO-1 gene promoter polymorphisms with risk for vascular diseases. Taken together, HO-1 has a great therapeutic potential for cardiovascular disease.

Mesenchymal stem cells for cardiac cell therapy

Despite refinements of medical and surgical therapies, heart failure remains a fatal disease. Myocardial infarction is the most common cause of heart failure, and only palliative measures are available to relieve symptoms and prolong the patient's life span. Because mammalian cardiomyocytes irreversibly exit the cell cycle at about the time of birth, the heart has traditionally been considered to lack any regenerative capacity. This paradigm, however, is currently shifting, and the cellular composition of the myocardium is being targeted by various regeneration strategies. Adult progenitor and stem cell treatment of diseased human myocardium has been carried out for more than 10 years (Menasche et al., 2001; Stamm et al., 2003), and it has become clear that, in humans, the regenerative capacity of hematopoietic stem cells and endothelial progenitor cells, despite potent proangiogenic effects, is limited (Stamm et al., 2009). More recently, mesenchymal stem cells (MSCs) and related cell types are being evaluated in preclinical models of heart disease as well as in clinical trials (see Published Clinical Trials, below). MSCs have the capacity to self-renew and to differentiate into lineages that normally originate from the embryonic mesenchyme (connective tissues, blood vessels, blood-related organs) (Caplan, 1991; Prockop, 1997; Pittenger et al., 1999). The current definition of MSCs includes plastic adherence in cell culture, specific surface antigen expression (CD105(+)/CD90(+)/CD73(+), CD34(-)/CD45(-)/CD11b(-) or CD14(-)/CD19(-) or CD79α(-)/HLA-DR1(-)), and multilineage in vitro differentiation potential (osteogenic, chondrogenic, and adipogenic) (Dominici et al., 2006 ). If those criteria are not met completely, the term "mesenchymal stromal cells" should be used for marrow-derived adherent cells, or other terms for MSC-like cells of different origin. For the purpose of this review, MSCs and related cells are discussed in general, and cell type-specific properties are indicated when appropriate. We first summarize the preclinical data on MSCs in models of heart disease, and then appraise the clinical experience with MSCs for cardiac cell therapy.

Induction of heme oxygenase-1 protects against nutritional fibrosing steatohepatitis in mice

BACKGROUND

Heme oxygenase-1 (HO-1), an antioxidant defense enzyme, has been shown to protect against oxidant-induced liver injury. However, its role on liver fibrosis remains unclear. This study aims to elucidate the effect and the mechanism of HO-1 in nutritional fibrosing steatohepatitis in mice.

METHODS

Male C57BL/6J mice were fed with a methionine-choline deficient (MCD) diet for eight weeks to induce hepatic fibrosis. HO-1 chemical inducer (hemin), HO-1 chemical inhibitor zinc protoporphyrin IX (ZnPP-IX) and/or adenovirus carrying HO-1 gene (Ad-HO-1) were administered to mice, respectively. Liver injury was assessed by serum ALT, AST levels and histological examination; hepatic lipid peroxides levels were determined; the expression levels of several fibrogenic related genes were assayed by real-time quantitative PCR and Western blot.

RESULTS

MCD feeding mice showed progressive hepatic injury including hepatic steatosis, inflammatory infiltration and fibrosis. Induction of HO-1 by hemin or Ad-HO-1 significantly attenuated the severity of liver injury. This effect was associated with the up-regulation of HO-1, reduction of hepatic lipid peroxides levels, down-regulation of inflammatory factors tumor necrosis factor-alpha, interleukin-6 and suppressor of cytokine signaling-1 as well as the pro-fibrotic genes alpha-smooth muscle actin, transforming growth factor-β1, matrix metallopeptidase-2 and matrix metallopeptidase-9. A contrary effect was observed in mice treated with ZnPP-IX.

CONCLUSIONS

The present study provided the evidence for the protective role of HO-1 in ameliorating MCD diet-induced fibrosing steatohepatitis. Modulation of HO-1 expression might serve as a therapeutic approach for fibrotic steatohepatitis.