Human MuStem Cell Grafting into Infarcted Rat Heart Attenuates Adverse Tissue Remodeling and Preserves Cardiac Function

Abstract

Myocardial infarction is one of the leading causes of mortality and morbidity worldwide. Whereas transplantation of several cell types into the infarcted heart has produced promising preclinical results, clinical studies using analogous human cells have shown limited structural and functional benefits. In dogs and humans, we have described a type of muscle-derived stem cells termed MuStem cells that efficiently promoted repair of injured skeletal muscle. Enhanced survival rate, long-term engraftment, and participation in muscle fiber formation were reported, leading to persistent tissue remodeling and clinical benefits. With the consideration of these features that are restricted or absent in cells tested so far for myocardial infarction, we wanted to investigate the capacity of human MuStem cells to repair infarcted hearts. Their local administration in immunodeficient rats 1 week after induced infarction resulted in reduced fibrosis and increased angiogenesis 3 weeks post-transplantation. Importantly, foci of human fibers were detected in the infarct site. Treated rats also showed attenuated left-ventricle dilation and preservation of contractile function. Interestingly, no spontaneous arrhythmias were observed. Our findings support the potential of MuStem cells, which have already been proposed as therapeutic candidates for dystrophic patients, to treat myocardial infarction and position them as an attractive tool for muscle-regenerative medicine.

Human MuStem cells repress T-cell proliferation and cytotoxicity through both paracrine and contact-dependent pathways

“…Human MuStem cells from 5 independent donors were expanded in vitro and analyzed at passage 5 (P5) using fluorescence-activated cell sorting (FACS). All hMuStem cells shared a typical expression pattern of myogenic progenitors with a signature of perivascular MSCs (Additional file 2 : Figure S1), in agreement with our previous findings [ 64 , 66 , 75 ]. Given that stimulation with pro-inflammatory cytokines modifies the phenotype of MSCs [ 73 ], hMuStem cells were cultured either in basal media or in presence of TNF-α and IFN-γ.…”

“…Human MuStem cells were independently isolated from muscle biopsies from 5 patients and cultured, as previously described [ 64 , 66 ]. For pro-inflammatory stimulation, cells were expanded until they reached approximately 60–70% confluence, and then the medium was changed for growth medium containing 50 ng/mL of both TNF-α and IFN-γ (Miltenyi, Bergisch Gladbach, Germany) and cultured for 24 h.…”

“…Based on their phenotype and plasticity, we have shown that these cells, referred as MuStem cells, correspond to early myogenic-committed progenitors with a mesenchymal perivascular profile. Importantly, these oligopotent stem cells display an interesting potential for skeletal and cardiac muscle repair [ 63 – 66 ]. After allogeneic transplantation into golden retriever muscular dystrophy (GRMD) dogs, a clinically relevant animal model of DMD, MuStem cells contribute to muscle fiber formation, induce long-term muscle fiber regeneration and limit the progression of muscle damage and fibrosis [ 63 , 67 ].…”

“…After allogeneic transplantation into golden retriever muscular dystrophy (GRMD) dogs, a clinically relevant animal model of DMD, MuStem cells contribute to muscle fiber formation, induce long-term muscle fiber regeneration and limit the progression of muscle damage and fibrosis [ 63 , 67 ]. Similarly, human MuStem (hMuStem) cells show in vivo a robust capacity for muscle regeneration after delivery into injured skeletal muscle in immunodeficient mice [ 64 ] and efficiently counteract adverse tissue remodeling, primarily by limiting fibrosis, in an immunodeficient rat model of myocardial infarction [ 66 ]. While these findings have positioned hMuStem cells as an attractive tool for muscle regenerative medicine, their immunoregulatory properties, which are pivotal for tissue remodeling, have not been investigated to date.…”

Label‐free 3D characterization of cardiac fibrosis in muscular dystrophy using SHG imaging of cleared tissue

“…Hematoxylin‐eosin‐saffron (HES) and picrosirius red staining were performed on 5‐μm‐thick sections cut for classical histopathological evaluation, as previously described (Lagalice et al., 2018; Rannou et al., 2020). For immunofluorescence analyses, frozen sections were permeabilized using 0.1% Triton X‐100 (Sigma‐Aldrich, Saint Quentin‐Fallavier, France) and incubated with blocking buffer consisting of a mixture of 5% goat serum and 5% bovine serum albumin (Sigma‐Aldrich) in 0.1 M phosphate‐buffered saline (PBS).…”