Early tirofiban versus heparin for bridging dual antiplatelet therapy in patients undergoing coronary endarterectomy combined with coronary artery bypass grafting: a multicenter randomized controlled trial protocol (the THACE-CABG trial).

BACKGROUND: For complete revascularization, patients with diffuse coronary artery disease should have a coronary endarterectomy and a coronary artery bypass graft (CE-CABG). Sadly, CE can lead to a lack of endothelium, which raises the risk of thrombotic events. Even though daily dual antiplatelet therapies (DAPT) have been shown to reduce thrombotic events, the risk of perioperative thrombotic events is high during the high-risk period after CE-CABG, and there is no consistent protocol to bridge DAPT. This trial aims to compare safety and efficacy between tirofiban and heparin as DAPT bridging strategies after CE-CABG. METHODS: In phase I, 266 patients undergoing CE-CABG will be randomly assigned to tirofiban and heparin treatment groups to compare the two treatments in terms of the primary safety endpoint, chest tube drainage in the first 24 h. If the phase I trial shows tirofiban non-inferiority, phase II will commence, in which an additional 464 patients will be randomly assigned. All 730 patients will be studied to compare major cardiovascular and cerebrovascular events (MACCEs) between the groups in the first 30 days after surgery. DISCUSSION: Given the possible benefits of tirofiban administration after CE-CABG, this trial has the potential to advance the field of adult coronary heart surgery. TRIAL REGISTRATION: chictr.org.cn, ChiCTR2200055697. Registered 6 January 2022. https://www.chictr.org.cn/com/25/showproj.aspx?proj=149451 . Current version: 20,220,620.

Mesenchymal Stromal Cells from Patients with Cyanotic Congenital Heart Disease are Optimal Candidate for Cardiac Tissue Engineering.

Engineered heart tissues (EHTs) are regarded as being the most promising alternative to synthetic materials, and autologous mesenchymal stem cells (MSCs) are widely used as seeding cells. However, few studies have evaluated the feasibility of using MSCs from patients with cyanotic congenital heart disease (C-CHD) as seeding cells for EHTs, in comparison with cells from patients of acyanotic congenital heart disease (A-CHD). In the present study, we cultured MSCs from A-CHD and C-CHD patients in normoxia or hypoxia conditions, and compared their pro-angiogenic, anti-apoptotic and inflammation-modulatory potentials. In vivo, we seeded the cells into collagen patches conjugated with, or without, proangiogenic cytokines, which were used to repair the right ventricular outflow tract (RVOT) of rats. The in vitro results showed that C-CHD MSCs expressed higher levels of VEGFA and VEGFR2, and secreted more pro-angiogenic and anti-inflammatory cytokines under hypoxic conditions. On the other hand, apoptosis-related genes from C-CHD MSCs were modulated adaptably, converting these cells into an anti-apoptotic phenotype. In vivo studies demonstrated that in 4 weeks after RVOT reconstruction, cytokine-immobilized patches seeded with C-CHD MSCs exhibited preserved morphology, prolonged cell survival and enhanced angiogenesis compared to A-CHD MSCs. C-CHD MSCs that undergo "naturally hypoxic precondition" present a better cell source for EHTs, which would provide a promising individualized biomaterial for C-CHD patients.

Comparison of adipose­ and bone marrow­derived stem cells in protecting against ox­LDL­induced inflammation in M1­macrophage­derived foam cells.

Adipose­derived stem cells (ADSCs) and bone marrow­derived stem cells (BMSCs) are considered to be prospective sources of mesenchymal stromal cells (MSCs), that can be used in cell therapy for atherosclerosis. The present study investigated whether ADSCs co­cultured with M1 foam macrophages via treatment with oxidized low­density lipoprotein (ox­LDL) would lead to similar or improved anti­inflammatory effects compared with BMSCs. ADSCs, peripheral blood monocytes, BMSCs and ox­LDL were isolated from ten coronary heart disease (CHD) patients. After three passages, the supernatants of the ADSCs and BMSCs were collected and systematically analysed by liquid chromatography­quadrupole time­of­flight­mass spectrometry (6530; Agilent Technologies, Inc., Santa Clara, CA, USA). Cis­9, trans­11 was deemed to be responsible for the potential differences in the metabolic characteristics of ADSCs and BMSCs. These peripheral blood monocytes were characterized using flow cytometry. Following peripheral blood monocytes differentiation into M1 macrophages, the formation of M1 foam macrophages was achieved through treatment with ox­LDL. Overall, 2x106 ADSCs, BMSCs or BMSCs+cis­9, trans­11 were co­cultured with M1 foam macrophages. Anti­inflammatory capability, phagocytic activity, anti­apoptotic capability and cell viability assays were compared among these groups. It was demonstrated that the accumulation of lipid droplets decreased following ADSCs, BMSCs or BMSCs+cis­9, trans­11 treatment in M1 macrophages derived from foam cells. Consistently, ADSCs exhibited great advantageous anti­inflammatory capabilities, phagocytic activity, anti­apoptotic capability activity and cell viability over BMSCs or BMSCs+cis­9, trans­11. Additionally, BMSCs+cis­9, trans­11 also demonstrated marked improvement in anti­inflammatory capability, phagocytic activity, anti­apoptotic capability activity and cell viability in comparison with BMSCs. The present results indicated that ADSCs would be more appropriate for transplantation to treat atherosclerosis than BMSCs alone or BMSCs+cis­9, trans­11. This may be an important mechanism to regulate macrophage immune function.

Lower Senescence of Adipose-Derived Stem Cells than Donor-Matched Bone Marrow Stem Cells for Surgical Ventricular Restoration.

Surgical ventricular reconstruction (SVR) can restore cardiac function for left ventricular aneurysm to some extent. However, the patches used in this treatment have some limitations such as stiffness and calcification. Engineering heart tissues (EHTs) have emerged as a promising biomaterial to repair damaged heart. Nevertheless, selecting optimal candidate cells for EHTs has been controversial. Aging is a major consideration for seed cells derived from elderly patients. Hence, this study was aimed to assess the proliferation of, antiapoptosis potential of, and expression of senescence-associated factors (eg, SA-ß-Gal, cyclin-dependent kinase inhibitor 2A (P16), cyclin-dependent kinase inhibitor 1 (P21) in adipose-derived stem cells (ADSCs), and bone marrow stem cells (BMSCs) in vitro. In addition, cardiac function, cell survival, and angiogenesis of ADSCs and BMSCs after SVR were assessed in vivo. The in vitro results showed that old ADSCs (OAs) grew faster; expressed lower levels of SA-ß-Gal, P16, and P21; and possessed more pronounced antiapoptosis activity than old BMSCs (OBs). The in vivo results demonstrated that 28 days after patch implantation, animals that received OAs patches showed better restoration of cardiac function than animals that received OBs patches. Meanwhile, old ADSCs possessed more potential regarding cell survival and angiogenesis. These results suggest that ADSCs may be superior to BMSCs with regard to autologous cell transplantation in elderly patients.

Improved Left Ventricular Aneurysm Repair with Cell- and Cytokine-Seeded Collagen Patches.

BACKGROUND: Engineered heart tissues (EHTs) present a promising alternative to current materials for surgical ventricular restoration (SVR); however, the clinical application remains limited by inadequate vascularization postimplantation. Moreover, a suitable and economic animal model for primary screening is another important issue. METHODS: Recently, we used 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride chemistry (EDC) to initiate a strengthened, cytokine-conjugated collagenous platform with a controlled degradation speed. In vitro, the biomaterial exhibited an enhanced mechanical strength maintaining a porous ultrastructure, and the constant release of cytokines promoted the proliferation of seeded human mesenchymal stem cells (hMSCs). In vivo, with the hMSC-seeded, cytokine-immobilized patch (MSCs + GF patch), we performed modified SVR for rats with left ventricular aneurysm postmyocardial infarction (MI). Overall, the rats that underwent modified SVR lost less blood and had lower mortality. After 4 weeks, the rats repaired with this cell-seeded, cytokine-immobilized patch presented preserved cardiac function, beneficial morphology, enhanced cell infiltration, and functional vessel formation compared with the cytokine-free (MSC patch), cell-free (GF patch), or blank controls (EDC patch). Furthermore, the degradable period of the collagen patch in vivo extended up to 3 months after EDC treatment. CONCLUSIONS: EDC may substantially modify collagen scaffold and provide a promising and practical biomaterial for SVR.

Phenotypic switching of vascular smooth muscle cells in the 'normal region' of aorta from atherosclerosis patients is regulated by miR-145.

Switching of vascular smooth muscle cells (VSMCs) from a contractile phenotype to an adverse proliferative phenotype is a hallmark of atherosclerosis or vascular restenosis. However, the genetic modulators responsible for this switch have not been fully elucidated in humans nor have they been correlated with clinical abnormalities. This study investigated genetic mechanisms involved in phenotypic switching of VSMCs at non-defect areas of the aorta in patients with atherosclerosis. Aortic wall samples were obtained from patients with (N = 53) and without (N = 27) atherosclerosis undergoing cardiovascular surgery. Vascular smooth muscle cell cultures were generated, and expression of microRNA-145 (miR-145), its target gene Kruppel-Like Factor 5 (KLF5) and Myocardin (MYOCD, a smooth muscle-specific transcriptional coactivator) were analysed using RT-qPCR, along with expression of relevant proteins. Vascular smooth muscle cells were transduced with miR-145 inhibitor and mimic to determine the effect of miR-145 expression on VSMC proliferation. miR-145 expression decreased while KLF5 expression increased in atherosclerotic aortas. Atherosclerotic samples and VSMCs had decreased expression of contractile markers calponin and alpha smooth muscle actin (α-SMA) and MYOCD. miR-145 inhibitor-transduced VSMCs from non-atherosclerotic patients showed decreased expression of calponin and α-SMA and increased proliferation compared with non-transduced controls, and these levels were close to those of atherosclerotic patients. miR-145 mimic-transduced VSMCs from atherosclerotic patients showed increased expression of calponin and α-SMA and decreased proliferation compared with non-transduced controls, and these levels were close to those found in non-atherosclerotic patients. These data demonstrate that miR-145 modulates the phenotypic switch of VSMCs from a contractile to a proliferative state via KLF5 and MYOCD in atherosclerosis.

MicroRNA-136 Promotes Vascular Muscle Cell Proliferation Through the ERK1/2 Pathway by Targeting PPP2R2A in Atherosclerosis.

Aberrant proliferation of vascular smooth muscle cells [VSMCs] is implicated in the pathogenesis of vascular pathologies such as atherosclerosis and restenosis. Accumulating evidences have revealed that microRNAs are involved in cell proliferation in various pathological conditions. In the present study, we showed that miR-136 was up regulated in human coronary atherosclerotic plaques when compared with normal coronary artery tissues. Moreover, miR-136 levels were up regulated in proliferative vascular smooth muscle cells induced by platelet-derived growth factor [PDGF] or serum. In cultured VSMCs, over expression of miR-136 stimulated cell proliferation. PPP2R2A was proved to be the direct target gene of miR-136 and knockdown of PPP2R2A had a proliferative effect on VSMCs. miR-136-induced PPP2R2A down-regulation was accompanied by increased expression of ERK1/2 phosphorylation. Inhibition of ERK1/2 abolished the effect of miR-136 and knockdown of PPP2R2A on VSMCs proliferation. In summary, aberrant miR-136 up regulation in atherosclerosis contributes to abnormal VSMC proliferation through suppressing the ERK1/2 pathway by targeting PPP2R2A. Our study also suggested that specific modulation of miR-136 in human VSMCs may provide a potential approach for the treatment of atherosclerosis.

Decreased SIRT3 in aged human mesenchymal stromal/stem cells increases cellular susceptibility to oxidative stress.

Sirtuin3 (SIRT3) is an important member of the sirtuin family of protein deacetylases that is localized to mitochondria and linked to lifespan extension in organisms ranging from yeast to humans. As aged cells have less regenerative capacity and are more susceptible to oxidative stress, we investigated the effect of ageing on SIRT3 levels and its correlation with antioxidant enzyme activities. Here, we show that severe oxidative stress reduces SIRT3 levels in young human mesenchymal stromal/stem cells (hMSCs). Overexpression of SIRT3 improved hMSCs resistance to the detrimental effects of oxidative stress. By activating manganese superoxide dismutase (MnSOD) and catalase (CAT), SIRT3 protects hMSCs from apoptosis under stress. SIRT3 expression, levels of MnSOD and CAT, as well as cell survival showed little difference in old versus young hMSCs under normal growth conditions, whereas older cells had a significantly reduced capacity to withstand oxidative stress compared to their younger counterparts. Expression of the short 28 kD SIRT3 isoform was higher, while the long 44 kD isoform expression was lower in young myocardial tissues compared with older ones. These results suggest that the active short isoform of SIRT3 protects hMSCs from oxidative injury by increasing the expression and activity of antioxidant enzymes. The expression of this short isoform decreases in cardiac tissue during ageing, leading to a reduced capacity for the heart to withstand oxidative stress.

Complement anaphylatoxin C4a inhibits C5a-induced neointima formation following arterial injury.

Interactions between complement anaphylatoxins have been investigated in numerous fields; however, their functions during arterial remodeling following injury have not been studied. The inhibitory effect of complement anaphylatoxin C4a on neointima formation induced by C5a following arterial injury was investigated. Mice were subjected to wire-induced endothelial denudation of the femoral artery and treated with C5a alone or C5a + C4a for two weeks. C4a significantly inhibited C5a-induced neointima formation and the expression of CD68, F4/80, tumor necrosis factor-α (TNF­α), interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1). In vitro, although C4a did not directly inhibit the migration, proliferation or the expression of vascular cell adhesion molecule-1 (VCAM-1) of C5a-induced vascular smooth muscle cells (VSMCs), C5a-pretreated conditioned medium­induced migration, proliferation and VCAM-1 expression of VSMCs were suppressed when VSMCs were exposed to conditioned medium from C4a-pretreated macrophages. In addition, C5a-induced TNF-α, IL-6 and MCP-1 expression, Ca2+ influx and extracellular signal-regulated kinase (ERK) activation in macrophages were suppressed by C4a. C4a inhibits C5a-induced neointima formation, not by acting directly on VSMCs, but via a macrophage-mediated reaction by inhibiting the Ca2+-dependent ERK pathway in macrophages.

[Effects of bio-mulching on rhizosphere soil microbial population, enzyme activity and tree growth in poplar plantation].

Coriaria nepalensis, Pteridium aquilinum var. latiuscukum, Imperata cylindrical var. major, and Quercus fabric were used as mulching materials to study their effects on the rhizosphere soil microbial population and enzyme activity and the tree growth in poplar plantation. The results showed that after mulching with test materials, the populations of both bacteria and fungi in rhizosphere soil were more than those of the control. Of the mulching materials, I. cylindrical and Q. fabric had the best effect, with the numbers of bacteria and fungi being 23.56 and 1.43 times higher than the control, respectively. The bacterial and fungal populations in rhizosphere soil increased with increasing mulching amount. When the mulching amount was 7.5 kg m(-2), the numbers of bacteria and fungi in rhizosphere soil were 0.5 and 5.14 times higher than the control, respectively. Under bio-mulching, the bacterial and fungal populations in rhizosphere soil had a similar annual variation trend, which was accorded with the annual fluctuation of soil temperature and got to the maximum in July and the minimum in December. The urease and phosphatase activities in rhizosphere soil also increased with increasing mulching amount. As for the effects of different mulching materials on the enzyme activities, they were in the order of C. nepalensis > P. aquilinum > I. cylindrical > Q. fabric. The annual variation of urease and phosphatase activities in rhizosphere soil was similar to that of bacterial and fungal populations, being the highest in July and the lowest in December. Bio-mulching promoted the tree height, DBH, and biomass of poplar trees significantly.