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1. Sodium tanshinone IIA sulfonate prevents the adverse left ventricular remodelling: Focus on polymorphonuclear neutrophil‐derived granule components

   https://doi.org/10.1111/jcmm.14306  

   Mao, Shuai ; Taylor, Shalina ; Chen, Qubo ; Zhang, Minzhou ; Hinek, Aleksander ( May 2019 , Journal of Cellular and Molecular Medicine)

   The aims of this study were to evaluate the effects of sodium tanshinone IIA sulfonate (STS) on left ventricular (LV) remodelling after for ST‐elevated myocardial infarction (STEMI).

   In this prospective, randomized clinical trial, 101 patients with the ST‐elevated MI (STEMI) and a successful reperfusion were immediately randomized to receive STS (80 mg qd for 7 days) or saline control, along with standard therapy. The primary effectiveness endpoint is the % change in LV end diastolic volumes index (%∆ LVEDVi) as measured by echocardiography from baseline to 6 months. Secondary effectiveness endpoints include 6‐month period for major adverse cardiac events (MACE), including the occurrence of recurrent myocardial infarction, death, hospitalization for heart failure and malignant arrhythmia. The 6‐month changes in %∆ LVEDVi were significantly smaller in the STS group than in the control group [−5.05% vs 3.32%;P < 0.001]. With respect to MACE, there was a significant difference between those who received STS (8.16%) and those patients on control (26.00%) (P = 0.019). Meaningfully, results of parallel tests aimed at mechanistic explanation of the reported clinical effects, revealed a significantly reduced levels of neutrophils‐derived granule components in the blood of STS treated patients.

   We found that short‐term treatment with STS reduced progressive left ventricular remodelling and subsequent better clinical outcome that could be mechanistically linked to the inhibition of the ultimate damage of infarcted myocardium by infiltrating neutrophils.

    

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2. Inflammasome Assays In Vitro and in Mouse Models

   https://doi.org/10.1002/cpim.107  

   Guo, Haitao ; Ting, Jenny P. ‐Y. ( October 2020 , Current Protocols in Immunology)

   This article presents assays that allow induction and measurement of activation of different inflammasomes in mouse macrophages, human peripheral blood mononuclear cell (PBMC) cultures, and mouse peritonitis and endotoxic shock models. Basic Protocol 1 describes how to prime the inflammasome in mouse macrophages with different Toll‐like receptor agonists and TNF‐α; how to induce NLRP1, NLRP3, NLRC4, and AIM2 inflammasome activation by their corresponding stimuli; and how to measure inflammasome activation‐mediated maturation of interleukin (IL)‐1β and IL‐18 and pyroptosis. Since the well‐established agonists for NLRP1 are inconsistent between mice and humans, Basic Protocol 2 describes how to activate the NLRP1 inflammasome in human PBMCs. Basic Protocol 3 describes how to purify, crosslink, and detect the apoptosis‐associated speck‐like protein containing a CARD (ASC) pyroptosome. Formation of the ASC pyroptosome is a signature of inflammasome activation. A limitation of ASC pyroptosome detection is the requirement of a relatively large cell number. Alternate Protocol 1 is provided to stain ASC pyroptosomes using an anti‐ASC antibody and to measure ASC specks by fluorescence microscopy in a single cell. Intraperitoneal injection of lipopolysaccharides (LPS) and inflammasome agonists will induce peritonitis, which is seen as an elevation of IL‐1β and other proinflammatory cytokines and an infiltration of neutrophils and inflammatory monocytes. Basic Protocol 4 describes how to induce NLRP3 inflammasome activation and peritonitis by priming mice with LPS and subsequently challenging them with monosodium urate (MSU). The method for measuring cytokines in serum and through peritoneal lavage is also described. Finally, Alternate Protocol 2 describes how to induce noncanonical NLRP3 inflammasome activation by high‐dose LPS challenge in a sepsis model. © 2020 Wiley Periodicals LLC.

   Basic Protocol 1: Priming and activation of inflammasomes in mouse macrophages

   Basic Protocol 2: Activation of human NLRP1 inflammasome by DPP8/9 inhibitor talabostat

   Basic Protocol 3: Purification and detection of ASC pyroptosome

   Alternate Protocol 1: Detection of ASC speck by immunofluorescence staining

   Basic Protocol 4: Activation of canonical NLRP3 inflammasome in mice by intraperitoneal delivery of MSU crystals

   Alternate Protocol 2: Activation of noncanonical NLRP3 inflammasome in mice by intraperitoneal delivery of LPS

    

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3. Local decorin delivery via hyaluronic acid microrods improves cardiac performance, ventricular remodeling after myocardial infarction

   https://doi.org/10.1038/s41536-023-00336-w  

   Mohindra, Priya ; Zhong, Justin X. ; Fang, Qizhi ; Cuylear, Darnell L. ; Huynh, Cindy ; Qiu, Huiliang ; Gao, Dongwei ; Kharbikar, Bhushan N. ; Huang, Xiao ; Springer, Matthew L. ; et al ( October 2023 , npj Regenerative Medicine)

   Heart failure (HF) remains a global public health burden and often results following myocardial infarction (MI). Following injury, cardiac fibrosis forms in the myocardium which greatly hinders cellular function, survival, and recruitment, thus severely limits tissue regeneration. Here, we leverage biophysical microstructural cues made of hyaluronic acid (HA) loaded with the anti-fibrotic proteoglycan decorin to more robustly attenuate cardiac fibrosis after acute myocardial injury. Microrods showed decorin incorporation throughout the entirety of the hydrogel structures and exhibited first-order release kinetics in vitro. Intramyocardial injections of saline (n = 5), microrods (n = 7), decorin microrods (n = 10), and free decorin (n = 4) were performed in male rat models of ischemia-reperfusion MI to evaluate therapeutic effects on cardiac remodeling and function. Echocardiographic analysis demonstrated that rats treated with decorin microrods (5.21% ± 4.29%) exhibited significantly increased change in ejection fraction (EF) at 8 weeks post-MI compared to rats treated with saline (−4.18% ± 2.78%,p < 0.001) and free decorin (−3.42% ± 1.86%,p < 0.01). Trends in reduced end diastolic volume were also identified in decorin microrod-treated groups compared to those treated with saline, microrods, and free decorin, indicating favorable ventricular remodeling. Quantitative analysis of histology and immunofluorescence staining showed that treatment with decorin microrods reduced cardiac fibrosis (p < 0.05) and cardiomyocyte hypertrophy (p < 0.05) at 8 weeks post-MI compared to saline control. Together, this work aims to contribute important knowledge to guide rationally designed biomaterial development that may be used to successfully treat cardiovascular diseases.

    

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4. 3D bioprinted aged human post‐infarct myocardium tissue model

   https://doi.org/10.1002/hsr2.1945  

   Basara, Gozde ; Celebi, Lara Ece ; Ronan, George ; Discua Santos, Victoria ; Zorlutuna, Pinar ( April 2024 , Health Science Reports)

   Fibrotic tissue formed after myocardial infarction (MI) can be as detrimental as MI itself. However, current in vitro cardiac fibrosis models fail to recapitulate the complexities of post‐MI tissue. Moreover, although MI and subsequent fibrosis is most prominent in the aged population, the field suffers from inadequate aged tissue models. Herein, an aged human post‐MI tissue model, representing the native microenvironment weeks after initial infarction, is engineered using three‐dimensional bioprinting via creation of individual bioinks to specifically mimic three distinct regions: remote, border, and scar.

   The aged post‐MI tissue model is engineered through combination of gelatin methacryloyl, methacrylated hyaluronic acid, aged type I collagen, and photoinitiator at variable concentrations with different cell types, including aged human induced pluripotent stem cell‐derived cardiomyocytes, endothelial cells, cardiac fibroblasts, and cardiac myofibroblasts, by introducing a methodology which utilizes three printheads of the bioprinter to model aged myocardium. Then, using cell‐specific proteins, the cell types that comprised each region are confirmed using immunofluorescence. Next, the beating characteristics are analyzed. Finally, the engineered aged post‐MI tissue model is used as a benchtop platform to assess the therapeutic effects of stem cell‐derived extracellular vesicles on the scar region.

   As a result, high viability (>74%) was observed in each region of the printed model. Constructs demonstrated functional behavior, exhibiting a beating velocity of 6.7 μm/s and a frequency of 0.3 Hz. Finally, the effectiveness of hiPSC‐EV and MSC‐EV treatment was assessed. While hiPSC‐EV treatment showed no significant changes, MSC‐EV treatment notably increased cardiomyocyte beating velocity, frequency, and confluency, suggesting a regenerative potential.

   In conclusion, we envision that our approach of modeling post‐MI aged myocardium utilizing three printheads of the bioprinter may be utilized for various applications in aged cardiac microenvironment modeling and testing novel therapeutics.

    

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5. In vivo assessment of mitral valve leaflet remodelling following myocardial infarction

   https://doi.org/10.1038/s41598-022-22790-0  

   Rego, Bruno V. ; Khalighi, Amir H. ; Lai, Eric K. ; Gorman, Robert C. ; Gorman, III, Joseph H. ; Sacks, Michael S. ( October 2022 , Scientific Reports)

   Each year, more than 40,000 people undergo mitral valve (MV) repair surgery domestically to treat regurgitation caused by myocardial infarction (MI). Although continual MV tissue remodelling following repair is believed to be a major contributor to regurgitation recurrence, the effects of the post-MI state on MV remodelling remain poorly understood. This lack of understanding limits our ability to predict the remodelling of the MV both post-MI and post-surgery to facilitate surgical planning. As a necessary first step, the present study was undertaken to noninvasively quantify the effects of MI on MV remodelling in terms of leaflet geometry and deformation. MI was induced in eight adult Dorset sheep, and real-time three-dimensional echocardiographic (rt-3DE) scans were collected pre-MI as well as at 0, 4, and 8 weeks post-MI. A previously validated image-based morphing pipeline was used to register corresponding open- and closed-state scans and extract local in-plane strains throughout the leaflet surface at systole. We determined that MI inducedpermanentchanges in leaflet dimensions in the diastolic configuration, which increased with time to 4 weeks, then stabilised. MI substantially affected the systolicshapeof the MV, and therange of stretchexperienced by the MV leaflet at peak systole was substantially reduced when referred to the current time-point. Interestingly, when we referred the leaflet strains to the pre-MI configuration, the systolic strains remained very similar throughout the post-MI period. Overall, we observed that post-MI ventricular remodeling induced permanent changes in the MV leaflet shape. This predominantly affected the MV’s diastolic configuration, leading in turn to a significant decrease in the range of stretch experienced by the leaflet when referenced to the current diastolic configuration. These findings are consistent with our previous work that demonstrated increased plastic (i.e. non-recoverable) leaflet deformations post-MI, that was completely accounted for by the associated changes in collagen fiber structure. Moreover, we demonstrated through noninvasive methods that the state of the MV leaflet can elucidate the progression and extent of MV adaptation following MI and is thus highly relevant to the design of current and novel patient specific minimally invasive surgical repair strategies.

    

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