Cardiac support device (ASD) delivers bone marrow stem cells repetitively to epicardium has promising curative effects in advanced heart failure

Next-Generation Cardiac Interfacing Technologies Using Nanomaterial-Based Soft Bioelectronics

Cardiac interfacing devices are essential components for the management of cardiovascular diseases, particularly in terms of electrophysiological monitoring and implementation of therapies. However, conventional cardiac devices are typically composed of rigid and bulky materials and thus pose significant challenges for effective long-term interfacing with the curvilinear surface of a dynamically beating heart. In this regard, the recent development of intrinsically soft bioelectronic devices using nanocomposites, which are fabricated by blending conductive nanofillers in polymeric and elastomeric matrices, has shown great promise. The intrinsically soft bioelectronics not only endure the dynamic beating motion of the heart and maintain stable performance but also enable conformal, reliable, and large-area interfacing with the target cardiac tissue, allowing for high-quality electrophysiological mapping, feedback electrical stimulations, and even mechanical assistance. Here, we explore next-generation cardiac interfacing strategies based on soft bioelectronic devices that utilize elastic conductive nanocomposites. We first discuss the conventional cardiac devices used to manage cardiovascular diseases and explain their undesired limitations. Then, we introduce intrinsically soft polymeric materials and mechanical restraint devices utilizing soft polymeric materials. After the discussion of the fabrication and functionalization of conductive nanomaterials, the introduction of intrinsically soft bioelectronics using nanocomposites and their application to cardiac monitoring and feedback therapy follow. Finally, comments on the future prospects of soft bioelectronics for cardiac interfacing technologies are discussed.

Effects of Adrenomedullin (ADM)-Modified Bone Marrow Mesenchymal Stem Cells (BMSCs) Transplantation on Cardiac Function and Matrix Metalloproteinase Levels in Rats with Heart Failure

After ADM gene treatment, bone marrow mesenchymal stem cells (BMSCs) were transplanted into rats with heart failure to study its effect on rat heart function and matrix metalloproteinases (MMPs) expression. The rats were assigned into control group, BMSCs group and ADM group. 4 weeks after transplantation, the rats’ cardiac function indexes were detected and the levels of MMP-2 and MMP-9 was measured by western blot. Echocardiography analysis showed significant differences between groups (except LVDd) (P < 0.05). BMSCs and ADM groups had significantly lower LVEF and LVFS levels than control group (P < 0.05) with a significantly higher level in ADM group than BMSCs group (P < 0.05). However, BMSCs and ADM groups presented a significantly higher LVDs (P < 0.05) without difference between them (P > 0.05). Interestingly, no difference of LVDd was found among groups (P > 0.05). MMP-2 and MMP-9 levels in BMSCs group were 0.389±0.021, 0.512±0.018, respectively, which were significantly elevated compared to control group (P < 0.05); MMP-2 and MMP-9 protein level in the ADM group was 0.440±0.018 and 0.539±0.032 respectively, which was significantly higher than control group (P < 0.05). Compared with BMSCs group, ADM group had significantly increased protein levels of MMP-2/9 (P < 0.05). In conclusion, ADM-modified BMSCs transplantation can significantly inhibit MMP-2 and MMP-9 level, thereby improving the heart function of rats with heart failure.

Cardioprotective effect of silicon-built restraint device (ASD), for left ventricular remodeling in rat heart failure model

This study aims to evaluate the feasibility and cardio-protective effects of biocompatible silicon-built restraint device (ASD) in the rat's heart failure (HF) model. The performance and compliance characteristics of the ASD device were assessed in vitro by adopting a pneumatic drive and ball burst test. Sprague-Dawley (SD) rats were divided into four groups (n = 6); control, HF, HF + CSD, and HF + ASD groups, respectively. Heart failure was developed by left anterior descending (LAD) coronary artery ligation in all groups except the control group. The ASD and CSD devices were implanted in the heart of HF + ASD and HF + CSD groups, respectively. The ASD's functional and expansion ability was found to be safe and suitable for attenuating ventricular remodeling. ASD-treated rats showed normal heart rhythm, demonstrated by smooth -ST and asymmetrical T-wave. At the same time, hemodynamic parameters of the HF + ASD group improved systolic and diastolic functions, reducing ventricular wall stress, which indicated reverse remodeling. The BNP values were reduced in the HF + ASD group, which confirmed ASD feasibility and reversed remodeling at a molecular level. Furthermore, the HF + ASD group with no fibrosis suggests that ASD has significant curative effects on the heart muscles. In conclusion, ASD was found to be a promising restraint therapy than the previously standard restraint therapies. Stepwise ASD fabrication process (a) 3D computer model of ASD was generated by using Rhinoceros 5.0 software (b) 3D blue wax model of ASD (c) Silicon was prepared by mixing the solutions (as per manufacturer instruction) (d) Blue wax model of ASD was immersed into liquid Silicon (e) ASD model was put into the oven for 3 hours at 50 °C. (f) Blue wax started melting from the ASD model (g) ASD model was built from pure silicon (h) Two access lines were linked to the ASD device, which was connected with an implantable catheter (Port-a-cath), scale bar 100 µm. (Nikon Ldx 2.0).

Therapeutic approach for global myocardial injury using bone marrow-derived mesenchymal stem cells by cardiac support device in rats

Bone marrow-derived mesenchymal stem cells (BMSCs) have been considered a promising therapeutic approach to cardiovascular disease. This study intends to compare the effect of BMSCs through a standard active cardiac support device (ASD) and intravenous injection on global myocardial injury induced by isoproterenol. BMSCs were cultured in vitro, and the transplanted cells were labeled with a fluorescent dye CM-Dil. Isoproterenol (ISO) was injected into the rats; 2 weeks later, the labeled cells were transplanted into ISO-induced heart-jury rats through the tail vein or ASD device for 5 days. The rats were sacrificed on the first day, the third day, and the fifth day after transplantation to observe the distribution of cells in the myocardium by fluorescence microscopy. The hemodynamic indexes of the left ventricle were measured before sacrificing. H&E staining and Masson's trichrome staining were used to evaluate the cardiac histopathology. In the ASD groups, after 3 days of transplantation, there were a large number of BMSCs on the epicardial surface, and after 5 days of transplantation, BMSCs were widely distributed in the ventricular muscle. But in the intravenous injection group, there were no labeled-BMSCs distributed. In the ASD + BMSCs-three days treated group and ASD + BMSCs -five days-treated group, left ventricular systolic pressure (LVSP), the maximum rate of left ventricular pressure rise (+dP/dt), the maximum rate of left ventricular pressure decline (-dP/dt) increased compared with model group and intravenous injection group (P < 0.05). By giving BMSCs through ASD device, cells can rapidly and widely distribute in the myocardium and significantly improve heart function.

Therapeutic advances in cardiac targeted drug delivery: from theory to practice

The most commonly used administration methods in clinics and life are oral administration, intravenous injection, and other systemic administration methods. Targeted administration must be an essential long-term development direction due to the limited availability and a high incidence of systemic side effects. Cardiovascular diseases (CVD) are the leading cause of death all over the world. Targeted drug delivery (TDD) methods with the heart as the target organ have developed rapidly and are diversified. This article reviews the research progress of various TDD methods around the world with a heart as the target organ. It is mainly divided into two parts: the targeting vector represented by nanoparticles and various TDD methods such as intracoronary injection, ventricular wall injection, pericardial injection, and implantable medical device therapy and put forward some suggestions on the development of targeting. Different TDD methods described in this paper have not been widely used in clinical practice, and some have not even completed preclinical studies. Targeted drug delivery still requires long-term efforts by many researchers to realize the true meaning of the heart. HIGHLIGHTS Targeted administration can achieve a better therapeutic effect and effectively reduce the occurrence of adverse reactions. Parenteral administration or medical device implantation can be used for targeted drug delivery. Combined with new dosage forms or new technologies, better-targeted therapy can be achieved. Clinical trials have confirmed the safety and effectiveness of several administration methods.

Systemic and local delivery of mesenchymal stem cells for heart renovation: Challenges and innovations

In the beginning stage of heart disease, the blockage of blood flow frequently occurs due to the persistent damage and even death of myocardium. Cicatricial tissue developed after the death of myocardium can affect heart function, which ultimately leads to heart failure. In recent years, several studies carried out about the use of stem cells such as embryonic, pluripotent, cardiac and bone marrow-derived stem cells as well as myoblasts to repair injured myocardium. Current studies focus more on finding appropriate measures to enhance cell homing and survival in order to increase paracrine function. Until now, there is no universal delivery route for mesenchymal stem cells (MSCs) for different diseases. In this review, we summarize the advantages and challenges of the systemic and local pathways of MSC delivery. In addition, we also describe some advanced measures of cell delivery to improve the efficiency of transplantation. The combination of cells and therapeutic substances could be the most reliable method, which allows donor cells to deliver sufficient amounts of paracrine factors and provide long-lasting effects. The cardiac support devices or tissue engineering techniques have the potential to facilitate the controlled release of stem cells on local tissue for a sustained period. A novel promising epicardial drug delivery system is highlighted here, which not only provides MSCs with a favorable environment to promote retention but also increases the contact area and a number of cells recruited in the heart muscle.

Optimizing Epicardial Restraint and Reinforcement Following Myocardial Infarction: Moving Towards Localized, Biomimetic, and Multitherapeutic Options

The mechanical reinforcement of the ventricular wall after a myocardial infarction has been shown to modulate and attenuate negative remodeling that can lead to heart failure. Strategies include wraps, meshes, cardiac patches, or fluid-filled bladders. Here, we review the literature describing these strategies in the two broad categories of global restraint and local reinforcement. We further subdivide the global restraint category into biventricular and univentricular support. We discuss efforts to optimize devices in each of these categories, particularly in the last five years. These include adding functionality, biomimicry, and adjustability. We also discuss computational models of these strategies, and how they can be used to predict the reduction of stresses in the heart muscle wall. We discuss the range of timing of intervention that has been reported. Finally, we give a perspective on how novel fabrication technologies, imaging techniques, and computational models could potentially enhance these therapeutic strategies.

A novel approach to devise the therapy for ventricular fibrillation by epicardial delivery of lidocaine using active hydraulic ventricular attaching support system: An experimental study in rats

Active hydraulic ventricular attaching support system (ASD) placed around the heart is not only a novel, nontransplant surgical device used for epicardial administration of drugs like lidocaine, but also a promising treatment option for ventricular fibrillation (VF) and arrhythmias. We hypothesize that lidocaine in 5 mg/kg dose released by ASD significantly improves the VF in the rat model. Sprague-Dawley (SD) rats were selected and were divided into four groups, intravenous injection (IV), epicardial infusion (EI), ASD, and control. ASD group was further divided into four subgroups for different lidocaine doses (i) ASD+A group (10 mg/kg), (ii) ASD+B group (5 mg/kg), (iii) ASD+C group (1 mg/kg), and (iv) ASD+D group (0.1 mg/kg). VF was induced with calcium chloride injection and was confirmed by electrocardiogram (ECG) in all the groups. VF was treated with different doses of lidocaine using different modes of administration. Data were analyzed using the SPSS 19.0 Chi-square tests and one-way analysis of variance (ANOVA). The Kaplan-Meier curve for OS was compared to the Logrank test based on the survival time. P < 0.05 was considered as statistically significant. ASD + B group (5 mg/kg) showed significantly reduced sgroup. The time of first sinus rhythm recovered (15.96 ± 21.77 min) and ▵T-SOD in plasma (-42.02 ± 26.99 U/mL) was significantly different than that of control, IV, and EI groups. ▵T-SOD in plasma for all ASD-treated groups was smaller than the control and IV groups. This study proves that ASD with 5 mg/kg lidocaine dose appears as a promising therapeutic platform for treating VF in rats. Furthermore, ASD may also have potential for treating VF or other cardiovascular disease with different therapeutic agents. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1722-1731, 2019.