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The Development of Macrophage-Mediated Cell Therapy to Improve Skeletal Muscle Function after Injury.

Rybalko V, Hsieh PL, Merscham-Banda M, Suggs LJ, Farrar RP - PLoS ONE (2015)

Bottom Line: A variety of MP phenotypes have been identified and characterized in vitro as well as in vivo.We detected a 15% improvement in specific tension and force normalized to mass after M1 (LPS/IFN-γ) MP transplantation 24 hours post-reperfusion.Interestingly, we found that M0 bone marrow-derived unpolarized MPs significantly impaired muscle function highlighting the complexity of temporally coordinated skeletal muscle regenerative program.

View Article: PubMed Central - PubMed

Affiliation: Department of Kinesiology, The University of Texas at Austin, 1 University Station D3700, Austin, TX 78712, United States of America.

ABSTRACT
Skeletal muscle regeneration following acute injury is a multi-step process involving complex changes in tissue microenvironment. Macrophages (MPs) are one of the key cell types involved in orchestration and modulation of the repair process. Multiple studies highlight the essential role of MPs in the control of the myogenic program and inflammatory response during skeletal muscle regeneration. A variety of MP phenotypes have been identified and characterized in vitro as well as in vivo. As such, MPs hold great promise for cell-based therapies in the field of regenerative medicine. In this study we used bone-marrow derived in vitro LPS/IFN-y-induced M1 MPs to enhance functional muscle recovery after tourniquet-induced ischemia/reperfusion injury (TK-I/R). We detected a 15% improvement in specific tension and force normalized to mass after M1 (LPS/IFN-γ) MP transplantation 24 hours post-reperfusion. Interestingly, we found that M0 bone marrow-derived unpolarized MPs significantly impaired muscle function highlighting the complexity of temporally coordinated skeletal muscle regenerative program. Furthermore, we show that delivery of M1 (LPS/IFN-γ) MPs early in regeneration accelerates myofiber repair, decreases fibrotic tissue deposition and increases whole muscle IGF-I expression.

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Analysis of the myofiber distribution 14 days post-reperfusion in GAS muscles treated with saline or 2x106in vitro polarized macrophages 24h after TK-I/R injury.(A) Representative H&E images of uninjured control GAS and injured, saline and MP treated GAS, at 14 days post-reperfusion; (B) Top: myofiber distribution in saline-treated group (black bars) relative to the contralateral uninjured control GAS(white bars); Middle: myofiber distribution after saline treatment (black bars) compared to M0 MP injected GAS (grey bars); Bottom: myofiber distribution following saline treatment (black bars) compared to M1(LPS/IFN-γ) MP treated GAS (pattern fill bars). n = 5/group; 3 fields of view/animal. Values expressed as mean ± SEM; (*) p<0.05 relative to saline; Student’s t-test.
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pone.0145550.g004: Analysis of the myofiber distribution 14 days post-reperfusion in GAS muscles treated with saline or 2x106in vitro polarized macrophages 24h after TK-I/R injury.(A) Representative H&E images of uninjured control GAS and injured, saline and MP treated GAS, at 14 days post-reperfusion; (B) Top: myofiber distribution in saline-treated group (black bars) relative to the contralateral uninjured control GAS(white bars); Middle: myofiber distribution after saline treatment (black bars) compared to M0 MP injected GAS (grey bars); Bottom: myofiber distribution following saline treatment (black bars) compared to M1(LPS/IFN-γ) MP treated GAS (pattern fill bars). n = 5/group; 3 fields of view/animal. Values expressed as mean ± SEM; (*) p<0.05 relative to saline; Student’s t-test.

Mentions: H&E analysis of muscle tissue was performed to evaluate whether increases in muscle functional recovery after M1 (LPS/IFN-γ) MP-treatment was also associated with improvements in gross muscle morphology (Fig 4A). While all treatment groups showed an increase in central nucleation relative to control, no differences in central nucleation were observed between groups (data not shown). As anticipated, we saw significant left-hand shift towards smaller myofiber diameter in injured saline-treated muscles as compared to uninjured control (Fig 4B, top) reflecting an ongoing tissue repair after TK-I/R injury. Myofiber distribution showed no significant differences in TK-injured saline-treated and M0 MP-treated muscles (Fig 4B, middle). M1 (LPS/IFN-γ) MP-treated group showed a meaningful decrease in myofibers of diameter ≤ 500 μm2 and increase in larger myofibers 1000–1500 μm2 and 1500–2000 μm2 in diameter (Fig 4B, bottom).


The Development of Macrophage-Mediated Cell Therapy to Improve Skeletal Muscle Function after Injury.

Rybalko V, Hsieh PL, Merscham-Banda M, Suggs LJ, Farrar RP - PLoS ONE (2015)

Analysis of the myofiber distribution 14 days post-reperfusion in GAS muscles treated with saline or 2x106in vitro polarized macrophages 24h after TK-I/R injury.(A) Representative H&E images of uninjured control GAS and injured, saline and MP treated GAS, at 14 days post-reperfusion; (B) Top: myofiber distribution in saline-treated group (black bars) relative to the contralateral uninjured control GAS(white bars); Middle: myofiber distribution after saline treatment (black bars) compared to M0 MP injected GAS (grey bars); Bottom: myofiber distribution following saline treatment (black bars) compared to M1(LPS/IFN-γ) MP treated GAS (pattern fill bars). n = 5/group; 3 fields of view/animal. Values expressed as mean ± SEM; (*) p<0.05 relative to saline; Student’s t-test.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4696731&req=5

pone.0145550.g004: Analysis of the myofiber distribution 14 days post-reperfusion in GAS muscles treated with saline or 2x106in vitro polarized macrophages 24h after TK-I/R injury.(A) Representative H&E images of uninjured control GAS and injured, saline and MP treated GAS, at 14 days post-reperfusion; (B) Top: myofiber distribution in saline-treated group (black bars) relative to the contralateral uninjured control GAS(white bars); Middle: myofiber distribution after saline treatment (black bars) compared to M0 MP injected GAS (grey bars); Bottom: myofiber distribution following saline treatment (black bars) compared to M1(LPS/IFN-γ) MP treated GAS (pattern fill bars). n = 5/group; 3 fields of view/animal. Values expressed as mean ± SEM; (*) p<0.05 relative to saline; Student’s t-test.
Mentions: H&E analysis of muscle tissue was performed to evaluate whether increases in muscle functional recovery after M1 (LPS/IFN-γ) MP-treatment was also associated with improvements in gross muscle morphology (Fig 4A). While all treatment groups showed an increase in central nucleation relative to control, no differences in central nucleation were observed between groups (data not shown). As anticipated, we saw significant left-hand shift towards smaller myofiber diameter in injured saline-treated muscles as compared to uninjured control (Fig 4B, top) reflecting an ongoing tissue repair after TK-I/R injury. Myofiber distribution showed no significant differences in TK-injured saline-treated and M0 MP-treated muscles (Fig 4B, middle). M1 (LPS/IFN-γ) MP-treated group showed a meaningful decrease in myofibers of diameter ≤ 500 μm2 and increase in larger myofibers 1000–1500 μm2 and 1500–2000 μm2 in diameter (Fig 4B, bottom).

Bottom Line: A variety of MP phenotypes have been identified and characterized in vitro as well as in vivo.We detected a 15% improvement in specific tension and force normalized to mass after M1 (LPS/IFN-γ) MP transplantation 24 hours post-reperfusion.Interestingly, we found that M0 bone marrow-derived unpolarized MPs significantly impaired muscle function highlighting the complexity of temporally coordinated skeletal muscle regenerative program.

View Article: PubMed Central - PubMed

Affiliation: Department of Kinesiology, The University of Texas at Austin, 1 University Station D3700, Austin, TX 78712, United States of America.

ABSTRACT
Skeletal muscle regeneration following acute injury is a multi-step process involving complex changes in tissue microenvironment. Macrophages (MPs) are one of the key cell types involved in orchestration and modulation of the repair process. Multiple studies highlight the essential role of MPs in the control of the myogenic program and inflammatory response during skeletal muscle regeneration. A variety of MP phenotypes have been identified and characterized in vitro as well as in vivo. As such, MPs hold great promise for cell-based therapies in the field of regenerative medicine. In this study we used bone-marrow derived in vitro LPS/IFN-y-induced M1 MPs to enhance functional muscle recovery after tourniquet-induced ischemia/reperfusion injury (TK-I/R). We detected a 15% improvement in specific tension and force normalized to mass after M1 (LPS/IFN-γ) MP transplantation 24 hours post-reperfusion. Interestingly, we found that M0 bone marrow-derived unpolarized MPs significantly impaired muscle function highlighting the complexity of temporally coordinated skeletal muscle regenerative program. Furthermore, we show that delivery of M1 (LPS/IFN-γ) MPs early in regeneration accelerates myofiber repair, decreases fibrotic tissue deposition and increases whole muscle IGF-I expression.

Show MeSH
Related in: MedlinePlus