Targeted regional injection of biocomposite microspheres alters post-myocardial infarction remodeling and matrix proteolytic pathways

Guided SEFFI and CaHA: A Retrospective Observational Study of an Innovative Protocol for Regenerative Aesthetics

Background/Objectives: This retrospective observational study sought to determine the efficacy and safety of an innovative combined treatment protocol using guided Superficial Enhanced Fluid Fat Injection (SEFFI) and calcium hydroxylapatite (CaHA) in facial rejuvenation. Methods: A total of 158 patients (149 females and 9 males) underwent the combined treatment of guided SEFFI and diluted/hyperdiluted CaHA. The study evaluated treatment outcomes at 30, 90, and 150 days post-treatment using the Global Aesthetic Improvement Scale (GAIS) and three-dimensional photogrammetric analysis. Results: The combined treatment demonstrated consistent enhancement in skin quality and facial volume across temporal, malar, zygomatic, and jawline regions. At 90 days post-treatment, substantial improvements were observed, with the GAIS scores reflecting significant enhancements in both skin quality and volume, which were sustained or slightly improved by 150 days. Minor complications, predominantly ecchymosis at the injection sites, resolved within a week, confirming the treatments' safety. Conclusions: The integration of guided SEFFI and CaHA resulted in significant improvements in skin quality and facial volume with minimal complications. Further research is recommended to consolidate these findings and explore long-term outcomes.

Reproducing extracellular matrix adverse remodelling of non-ST myocardial infarction in a large animal model

The rising incidence of non-ST-segment elevation myocardial infarction (NSTEMI) and associated long-term high mortality constitutes an urgent clinical issue. Unfortunately, the study of possible interventions to treat this pathology lacks a reproducible pre-clinical model. Indeed, currently adopted small and large animal models of MI mimic only full-thickness, ST-segment-elevation (STEMI) infarcts, and hence cater only for an investigation into therapeutics and interventions directed at this subset of MI. Thus, we develop an ovine model of NSTEMI by ligating the myocardial muscle at precise intervals parallel to the left anterior descending coronary artery. Upon histological and functional investigation to validate the proposed model and comparison with STEMI full ligation model, RNA-seq and proteomics show the distinctive features of post-NSTEMI tissue remodelling. Transcriptome and proteome-derived pathway analyses at acute (7 days) and late (28 days) post-NSTEMI pinpoint specific alterations in cardiac post-ischaemic extracellular matrix. Together with the rise of well-known markers of inflammation and fibrosis, NSTEMI ischaemic regions show distinctive patterns of complex galactosylated and sialylated N-glycans in cellular membranes and extracellular matrix. Identifying such changes in molecular moieties accessible to infusible and intra-myocardial injectable drugs sheds light on developing targeted pharmacological solutions to contrast adverse fibrotic remodelling.

Wharton's Jelly Mesenchymal Stromal Cells and Derived Extracellular Vesicles as Post-Myocardial Infarction Therapeutic Toolkit: An Experienced View

Outstanding progress has been achieved in developing therapeutic options for reasonably alleviating symptoms and prolonging the lifespan of patients suffering from myocardial infarction (MI). Current treatments, however, only partially address the functional recovery of post-infarcted myocardium, which is in fact the major goal for effective primary care. In this context, we largely investigated novel cell and TE tissue engineering therapeutic approaches for cardiac repair, particularly using multipotent mesenchymal stromal cells (MSC) and natural extracellular matrices, from pre-clinical studies to clinical application. A further step in this field is offered by MSC-derived extracellular vesicles (EV), which are naturally released nanosized lipid bilayer-delimited particles with a key role in cell-to-cell communication. Herein, in this review, we further describe and discuss the rationale, outcomes and challenges of our evidence-based therapy approaches using Wharton's jelly MSC and derived EV in post-MI management.

Elastin-like recombinamers-based hydrogel modulates post-ischemic remodeling in a non-transmural myocardial infarction in sheep

Ischemic heart disease is a leading cause of mortality due to irreversible damage to cardiac muscle. Inspired by the post-ischemic microenvironment, we devised an extracellular matrix (ECM)-mimicking hydrogel using catalyst-free click chemistry covalent bonding between two elastin-like recombinamers (ELRs). The resulting customized hydrogel included functional domains for cell adhesion and protease cleavage sites, sensitive to cleavage by matrix metalloproteases overexpressed after myocardial infarction (MI). The scaffold permitted stromal cell invasion and endothelial cell sprouting in vitro. The incidence of non-transmural infarcts has increased clinically over the past decade, and there is currently no treatment preventing further functional deterioration in the infarcted areas. Here, we have developed a clinically relevant ovine model of non-transmural infarcts induced by multiple suture ligations. Intramyocardial injections of the degradable ELRs-hydrogel led to complete functional recovery of ejection fraction 21 days after the intervention. We observed less fibrosis and more angiogenesis in the ELRs-hydrogel-treated ischemic core region compared to the untreated animals, as validated by the expression, proteomic, glycomic, and histological analyses. These findings were accompanied by enhanced preservation of GATA4⁺ cardiomyocytes in the border zone of the infarct. We propose that our customized ECM favors cardiomyocyte preservation in the border zone by modulating the ischemic core and a marked functional recovery. The functional benefits obtained by the timely injection of the ELRs-hydrogel in a clinically relevant MI model support the potential utility of this treatment for further clinical translation.

Left ventricular restoration devices post myocardial infarction

Even in the era of percutaneous reperfusion therapy, left ventricular (LV) remodeling after myocardial infarction (MI) leading to heart failure remains a major health concern. Contractile dysfunction of the infarcted myocardium results in an increased pressure load, leading to maladaptive reshaping of the LV. Several percutaneous transcatheter procedures have been developed to deliver devices that restore LV shape and function. The purposes of this review are to discuss the spectrum of transcatheter devices that are available or in development for attenuation of adverse LV remodeling and to critically examine the available evidence for improvement of functional status and cardiovascular outcomes.

A Swine Model of Percutaneous Intracoronary Ethanol Induced Acute Myocardial Infarction and Ischemic Mitral Regurgitation

Ischemic mitral regurgitation (IMR) is a frequent complication after a myocardial infarction (MI), which doubles mortality. Transcatheter mitral repairs are emerging as alternative treatment options to open heart surgery for IMR, but animal models to test them are lacking. We report a percutaneous swine model of IMR. Seventeen swine were randomized to (group 1, n = 12) MI causing IMR, and (group 2, n = 5) controls. In group 1, MI was induced via percutaneous ethanol injection into the obtuse marginal branches of the left circumflex artery, resulting in ST elevating myocardial infarction. Nine animals were survived to 8-10 weeks with weekly echocardiograms and three swine were survived to 16-20 weeks with MRI at termination. In group 1 animals, average IMR fraction at termination was 26.6 ± 2.3% in the echo group, and 24.51 ± 0.41% in the MRI group. None of the animals in group 2 had IMR. Left ventricular dysfunction and significant dilatation were evident in group 1 animals, compared to the controls. In conclusion, a reproducible model of IMR is reported for use in pre-clinical testing of new mitral technologies.

Ventricular wall biomaterial injection therapy after myocardial infarction: Advances in material design, mechanistic insight and early clinical experiences

Intramyocardial biomaterial injection therapy for myocardial infarction has made significant progress since concept initiation more than 10 years ago. The interim successes and progress in the first 5 years have been extensively reviewed. During the last 5 years, two phase II clinical trials have reported their long term follow up results and many additional biomaterial candidates have reached preclinical and clinical testing. Also in recent years deeper investigations into the mechanisms behind the beneficial effects associated with biomaterial injection therapy have been pursued, and a variety of process and material parameters have been evaluated for their impact on therapeutic outcomes. This review explores the advances made in this biomaterial-centered approach to ischemic cardiomyopathy and discusses potential future research directions as this therapy seeks to positively impact patients suffering from one of the world's most common sources of mortality.

Early changes of left ventricular filling pattern after reperfused ST-elevation myocardial infarction and doxycycline therapy: Insights from the TIPTOP trial

AIM

Metalloproteinases inhibition by doxycycline reduces cardiac protein degradation at extracellular and intracellular level in the experimental model ischemia/reperfusion injury. Since both extracellular cardiac matrix and titin filaments inside the cardiomyocyte are responsible for the myocardial stiffness, we hypothesized that doxycycline could favorably act on left ventricular (LV) filling pressures in patients after reperfused acute ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Seventy-three of 110 patients of the TIPTOP trial underwent a 2D-Echo-Doppler on admission, and at pre-discharge and at 6-month after a primary PCI for STEMI and LV dysfunction. From admission to pre-discharge, LV filling changed from a high filling pressure (HFP) to a normal filling pressure (NFP) pattern in 91% of the doxycycline-group, and in 67% of the control-group. Conversely, 1% of the doxycycline-group, and 37% of the control-group changed the LV filling from NFP to HFP pattern. Overall, a pre-discharge HFP pattern was present in 4 patients (11%) of the doxycycline-group and in 13 patients (36%) of the control-group (p=0.025). The evaluation of metalloproteinases and their tissue inhibitors plasma concentrations provide possible favorable action of doxycycline. On the multivariate analyses, troponine I peak (p=0.026), doxycycline (p=0.033), and on admission to pre-discharge LVEF changes (p=0.044) were found to be associated with pre-discharge HFP pattern. Independently of their baseline LV filling behavior, the 6-month remodeling was less in patients with pre-discharge NFP pattern than in patients with HFP pattern.

CONCLUSIONS

In patients with STEMI and LV dysfunction doxycycline can favorably modulate the LV filling pattern early after primary PCI.

Targeted injection of a biocomposite material alters macrophage and fibroblast phenotype and function following myocardial infarction: relation to left ventricular remodeling

A treatment target for progressive left ventricular (LV) remodeling prevention following myocardial infarction (MI) is to affect structural changes directly within the MI region. One approach is through targeted injection of biocomposite materials, such as calcium hydroxyapatite microspheres (CHAM), into the MI region. In this study, the effects of CHAM injections upon key cell types responsible for the MI remodeling process, the macrophage and fibroblast, were examined. MI was induced in adult pigs before randomization to CHAM injections (20 targeted 0.1-ml injections within MI region) or saline. At 7 or 21 days post-MI (n = 6/time point per group), cardiac magnetic resonance imaging was performed, followed by macrophage and fibroblast isolation. Isolated macrophage profiles for monocyte chemotactic macrophage inflammatory protein-1 as measured by real-time polymerase chain reaction increased at 7 days post-MI in the CHAM group compared with MI only (16.3 ± 6.6 versus 1.7 ± 0.6 cycle times values, P < 0.05), and were similar by 21 days post-MI. Temporal changes in fibroblast function and smooth muscle actin (SMA) expression relative to referent control (n = 5) occurred with MI. CHAM induced increases in fibroblast proliferation, migration, and SMA expression-indicative of fibroblast transformation. By 21 days, CHAM reduced LV dilation (diastolic volume: 75 ± 2 versus 97 ± 4 ml) and increased function (ejection fraction: 48 ± 2% versus 38 ± 2%) compared with MI only (both P < 0.05). This study identified that effects on macrophage and fibroblast differentiation occurred with injection of biocomposite material within the MI, which translated into reduced adverse LV remodeling. These unique findings demonstrate that biomaterial injections impart biologic effects upon the MI remodeling process over any biophysical effects.

Preclinical evaluation of the engineered stem cell chemokine stromal cell-derived factor 1α analog in a translational ovine myocardial infarction model

RATIONALE

After myocardial infarction, there is an inadequate blood supply to the myocardium, and the surrounding borderzone becomes hypocontractile.

OBJECTIVE

To develop a clinically translatable therapy, we hypothesized that in a preclinical ovine model of myocardial infarction, the modified endothelial progenitor stem cell chemokine, engineered stromal cell-derived factor 1α analog (ESA), would induce endothelial progenitor stem cell chemotaxis, limit adverse ventricular remodeling, and preserve borderzone contractility.

METHODS AND RESULTS

Thirty-six adult male Dorset sheep underwent permanent ligation of the left anterior descending coronary artery, inducing an anteroapical infarction, and were randomized to borderzone injection of saline (n=18) or ESA (n=18). Ventricular function, geometry, and regional strain were assessed using cardiac MRI and pressure-volume catheter transduction. Bone marrow was harvested for in vitro analysis, and myocardial biopsies were taken for mRNA, protein, and immunohistochemical analysis. ESA induced greater chemotaxis of endothelial progenitor stem cells compared with saline (P<0.01) and was equivalent to recombinant stromal cell-derived factor 1α (P=0.27). Analysis of mRNA expression and protein levels in ESA-treated animals revealed reduced matrix metalloproteinase 2 in the borderzone (P<0.05), with elevated levels of tissue inhibitor of matrix metalloproteinase 1 and elastin in the infarct (P<0.05), whereas immunohistochemical analysis of borderzone myocardium showed increased capillary and arteriolar density in the ESA group (P<0.01). Animals in the ESA treatment group also had significant reductions in infarct size (P<0.01), increased maximal principle strain in the borderzone (P<0.01), and a steeper slope of the end-systolic pressure-volume relationship (P=0.01).

CONCLUSIONS

The novel, biomolecularly designed peptide ESA induces chemotaxis of endothelial progenitor stem cells, stimulates neovasculogenesis, limits infarct expansion, and preserves contractility in an ovine model of myocardial infarction.

A nonthoracotomy myocardial infarction model in an ovine using autologous platelets

Objective. There is a paucity of a biological large animal model of myocardial infarction (MI). We hypothesized that, using autologous-aggregated platelets, we could create an ovine model that was reproducible and more closely mimicked the pathophysiology of MI. Methods. Mepacrine stained autologous platelets from male sheep (n = 7) were used to create a myocardial infarction via catheter injection into the mid-left anterior descending (LAD) coronary artery. Serial daily serum troponin measurements were taken and tissue harvested on post-embolization day three. Immunofluorescence microscopy was used to detect the mepacrine-stained platelet-induced thrombus, and histology performed to identify three distinct myocardial (infarct, peri-ischemic “border zone,” and remote) zones. Results. Serial serum troponin levels (μg/mL) measured 0.0 ± 0.0 at baseline and peaked at 297.4 ± 58.0 on post-embolization day 1, followed by 153.0 ± 38.8 on day 2 and 76.7 ± 19.8 on day 3. Staining confirmed distinct myocardial regions of inflammation and fibrosis as well as mepacrine-stained platelets as the cause of intravascular thrombosis. Conclusion. We report a reproducible, unique model of a biological myocardial infarction in a large animal model. This technique can be used to study acute, regional myocardial changes following a thrombotic injury.

Integrating the myocardial matrix into heart failure recognition and management

In contrast to public perception, the morbidity and mortality and the resultant healthcare costs associated with chronic heart failure (HF) are increasing and arguably reaching epidemic proportions. Although basic research efforts have provided unique insights into fundamental processes that govern myocardial extracellular matrix (ECM) growth and function, the translation of these findings to improved diagnostics and therapeutics for HF has not been as forthcoming. The factors that contribute to this relative paucity of new clinical tools for HF are multifactorial but likely include the need to recognize and differentiate HF phenotypes and to couple the use of biomarkers and multimodality imaging in early translational research studies. Recognizing the classification scheme of HF with a reduced ejection fraction (EF) to that of HF with a preserved EF and incorporating unique and differential measurements of ECM remodeling to these specific disease processes are warranted. For example, profiling pathways of ECM degradation such as the matrix metalloproteinases in patients with ischemic heart disease and HF with a reduced EF can provide prognostic information in terms of risk of progression to HF. In patients with chronic hypertensive disease and HF with a preserved EF, plasma profiling indexes of ECM synthesis and turnover, as well as advances in ECM imaging, have been shown to provide diagnostic and prognostic use. In terms of therapeutics, strategies to stabilize the ECM in HF with a reduced EF hold potential, whereas in contradistinction, selective antifibrotic agents may hold promise for HF with a preserved EF.

Localized targeting of biomaterials following myocardial infarction: a foundation to build on

Acute coronary syndromes can give rise to myocardial injury infarction (MI), which in turn promulgates a series of cellular and extracellular events that result in left ventricular (LV) dilation and dysfunction. Localized strategies focused upon interrupting this inexorable process include delivery of bioactive molecules and stem cell derivatives. These localized treatment strategies are often delivered in a biomaterial complex in order to facilitate elution of the bioactive molecules or stem cell engraftment. However, these biomaterials can impart significant and independent effects upon the MI remodeling process. In addition, significant changes in local cell and interstitial biology within the targeted MI region can occur following injection of certain biomaterials, which may hold important considerations when using these materials as matrices for adjuvant drug/cell therapies.

Mitral valve surgery for dilated cardiomyopathy: current status and future roles

There are a large number of patients with functional mitral regurgitation resulting from dilated cardiomyopathy. The decision between surgical correction and medical management of severe mitral regurgitation in heart failure can be difficult. The data regarding long-term benefits and mortality after surgical intervention are contradictory. Recent data suggest that mitral regurgitation can be surgically corrected in heart failure with symptomatic improvements and beneficial reverse remodeling. Contrary to prior beliefs, mitral valve repair can be performed safely with minimal postoperative mortality. Data from multi-institutional, randomized prospective trials will help to elucidate many of the questions and concerns regarding repair of severe functional mitral regurgitation.