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Purpose To determine whether magnetization transfer (MT) magnetic resonance (MR) imaging may serve as a quantitative measure of the degree of fiber formation during differentiation of muscle precursor cells into engineered muscle tissue as a potential noninvasive monitoring tool in mice. Materials and Methods The study was approved by the local ethics committee (no. StV 01/2008) and the local Veterinary Office (license no. 99/2013). Human muscle progenitor cells (hMPCs) derived from rectus abdominis muscles were subcutaneously injected into CD-1 nude mice (CD-1 nude mice, Crl:CD1-Foxn1

Magnetic stimulation (MS) has the ability to induce muscle twitch and has long been proposed as a therapeutic modality for skeletal muscle diseases. However, the molecular mechanisms underlying its means of action have not been defined.; Muscle regeneration after trauma was studied in a standard muscle injury mouse model. The influence of MS on the formation of motor units, posttrauma muscle/nerve regeneration, and vascularization was investigated.; We found that MS does not cause systemic or muscle damage but improves muscle regeneration by significantly minimizing the presence of inflammatory infiltrate and formation of scars after trauma. It avoids posttrauma muscle atrophy, induces muscle hypertrophy, and increases the metabolism and turnover of muscle. It triples the expression of muscle markers and significantly improves muscle functional recovery after trauma.; Our results indicate that MS supports muscle and nerve regeneration by activating muscle-nerve cross-talk and inducing the maturation of neuromuscular junctions. Muscle Nerve 53: 598-607, 2016.

Background Skeletal muscle has a remarkable regenerative capacity. However, extensive damage that exceeds the self-regenerative ability of the muscle can lead to irreversible fibrosis, scarring, and significant loss of function. Adipose-derived stem cells (ADSC) are a highly abundant source of progenitor cells that have been previously reported to support the regeneration of various muscle tissues, including striated muscles. The aim of this study was to evaluate the effect of ADSC transplantation on functional skeletal muscle regeneration in an acute injury model. Methods Mouse ADSC were isolated from subcutaneous fat tissue and transplanted with a collagen hydrogel into the crushed tibialis anterior muscle of mice. Recovering muscles were analyzed for gene and protein expression by real-time quantitative polymerase chain reaction and immunohistochemistry. The muscle contractility was assessed by myography in an organ bath system. Results Intramuscular transplantation of ADSC into crushed tibialis anterior muscle leads to an improved muscle regeneration with ADSC residing in the damaged area. We did not observe ADSC differentiation into new muscle fibers or endothelial cells. However, the ADSC-injected muscles had improved contractility in comparison with the collagen-injected controls 28 days post-transplantation. Additionally, an increase in fiber cross-sectional size and in the number of mature fibers with centralized nuclei was observed. Conclusions ADSC transplantation into acute damaged skeletal muscle significantly improves functional muscle tissue regeneration without direct participation in muscle fiber formation. Cellular therapy with ADSC represents a novel approach to promote skeletal muscle regeneration. Electronic supplementary material The online version of this article (10.1186/s13287-018-0922-1) contains supplementary material, which is available to authorized users.

While many groups demonstrated new muscle tissue formation after muscle precursor cell (MPC) injection, the capacity of these cells to heal muscle damage, for example, sphincter in stress urinary incontinence, in long-term is still limited. Therefore, the first goal of our project was to optimize the functional regenerative potential of hMPC by genetic modification to overexpress human peroxisome proliferator-activated receptor gamma coactivator 1-alpha (hPGC-1α), key regulator of exercise-mediated adaptation. Moreover, we aimed at establishing a feasible methodology for noninvasive PET visualization of implanted cells and their microenvironment in muscle crush injury model. PGC-1α-bioengineered muscles showed enhanced marker expression for myogenesis (α-actinin, MyHC, and Desmin), vascularization (VEGF), neuronal (ACHE), and mitochondrial (COXIV) activity. Consistently, use of hPGC-1α_hMPCs produced significantly increased contractile force one to three weeks postinjury. PET imaging showed distinct differences in radiotracer signals ([18F]Fallypride and [11C]Raclopride (both targeting dopamine 2 receptors (D2R)) and [64Cu]NODAGA-RGD (targeting neovascularization)) between GFP_hMPCs and hD2R_hPGC-1α_hMPCs. After muscle harvesting, inflammation levels were in parallel to radiotracer uptake amount, with significantly lower uptake in hPGC-1α overexpressing samples. In summary, we facilitated early functional muscle tissue regeneration, introducing a novel approach to improve skeletal muscle regeneration. Besides successful tracking of hMPCs in muscle crush injuries, we showed that in high-inflammation areas, the specificity of radioligands might be significantly reduced, addressing a possible bottleneck of neovascularization PET imaging., STEM CELLS INTERNATIONAL, 2018

The ability of fish retinal ganglion cells (RGCs) to regenerate their axons was shown to require the re-expression and function of the two proteins reggie-1 and -2. RGCs in mammals fail to upregulate reggie expression and to regenerate axons after lesion suggesting the possibility that induced upregulation might promote regeneration. In the present study, RGCs in adult rats were induced to express reggie-1 by intravitreal injection of adeno-associated viral vectors (AAV2/1) expressing reggie-1 (AAV.R1-EGFP) 14d prior to optic nerve crush. Four weeks later, GAP-43-positive regenerating axons had crossed the lesion and grown into the nerve at significantly higher numbers and length (up to 5 mm) than the control transduced with AAV.EGFP. Consistently, after transduction with AAV.R1-EGFP as opposed to AAV.EGFP, primary RGCs in vitro grew long axons on chondroitin sulfate proteoglycan (CSPG) and Nogo-A, both glial cell-derived inhibitors of neurite growth, suggesting that reggie-1 can provide neurons with the ability to override inhibitors of neurite growth. This reggie-1-mediated enhancement of growth was reproduced in mouse hippocampal and N2a neurons which generated axons 40–60% longer than their control counterparts. This correlates with the reggie-1-dependent activation of Src and PI3 kinase (PI3K), of the Rho family GTPase Rac1 and downstream effectors such as cofilin. This increased growth also depends on TC10, the GTPase involved in cargo delivery to the growth cone. Thus, the upregulation of reggie-1 in mammalian neurons provides nerve cells with neuron-intrinsic properties required for axon growth and successful regeneration in the adult mammalian CNS.

1467 Objectives Automatic lesion segmentation is an important step towards standardizing early response measurements using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in combination with X-ray computed tomography (CT). In this study, the performance of different automatic segmentation algorithms for early response monitoring in non-small cell lung cancer (NSCLC) patients during chemo-radiotherapy was evaluated. Methods Twenty-seven patients with locally advanced NSCLC treated with concomitant chemo-radiotherapy underwent combined FDG-PET/CT imaging before and in the second week of treatment. Several image segmentation methods were used including fixed threshold segmentation at(i)40% SUVmax (T40),(ii) 50% SUVmax (T50), (iii) relative threshold level (RTL), (iv) signal to background ratio (SBR), and (v) fuzzy locally adaptive Bayesian (FLAB) segmentation. The predictive value of different PET parameters, including metabolic tumour volume (MTV), mean standardized uptake value (SUVmean), and total lesion glycolysis (TLG) of the primary tumor and lymph nodes for progression free survival (PFS) and overall survival (OS) was determined using a Cox proportional hazards model. Results The MTVs for primary tumour showed a high degree of conformity regarding shape and spatial overlap on both pre- and in-treatment FDG PET images. However, due to limited size and contrast, there were considerably more segmentation failures when performing lymph node segmentation. Of all algorithms, SBR and FLAB had the fewest lymph node segmentation failures for both pre- and in-treatment FDG PET images. The importance of adequate lymph node segmentation was reflected by a stronger association of PFS and OS when lymph nodes are included in the TLG calculation, yielding a summed TLG. Pre-treatment TLG was significantly associated with PFS and OS, regardless of the segmentation algorithm used. This was also the case for relative TLG decrease (ΔTLG) between the pre- and in-treatment TLG, with the exception of the RTL and T40 method when considering OS. Conclusions Pre-treatment TLG was significantly associated with PFS and OS in NSCLC patients treated with concomitant chemo-radiotherapy, regardless of the segmentation algorithm used and despite the limited number of patients. This is also the case for ΔTLG, with the exception of the RTL and T40 method. Significance levels increased when lymph node TLG was included in the analysis emphasizing the importance of adequate lymph node segmentation in PET images.

Magnetic stimulation (MS) has the ability to induce muscle twitch and has long been proposed as a therapeutic modality for skeletal muscle diseases. However, the molecular mechanisms underlying its means of action have not been defined.Muscle regeneration after trauma was studied in a standard muscle injury mouse model. The influence of MS on the formation of motor units, posttrauma muscle/nerve regeneration, and vascularization was investigated.We found that MS does not cause systemic or muscle damage but improves muscle regeneration by significantly minimizing the presence of inflammatory infiltrate and formation of scars after trauma. It avoids posttrauma muscle atrophy, induces muscle hypertrophy, and increases the metabolism and turnover of muscle. It triples the expression of muscle markers and significantly improves muscle functional recovery after trauma.Our results indicate that MS supports muscle and nerve regeneration by activating muscle-nerve cross-talk and inducing the maturation of neuromuscular junctions.

INTRODUCTION AND OBJECTIVES: Regenerative medicine using autologous stem cells offers an alternative therapy for skeletal muscle diseases, including stress urinary incontinence. To better understand the engrafting of the injected cells novel imaging technologies are needed. In this study we investigated the possibility of using a mutated dopamine D2-receptor and PET Imaging for precise localization and long-term in vivo tracking of the implanted muscle precursor cells. METHODS: Human muscle precursor cells (hMPCs) were isolated from biopsies of the M. rectus abdominis and expanded in culture. We have genetically modified these cells to express a mutated dopamine-D2R, as tracers for D2R imaging are already used in clinics. The infected hMPCs were characterized via immunocytochemistry and FACS using muscle-specific markers (MyHC, Pax7, Desmin, a-actinin). The modified cells were visualized with Positron emission tomography (PET) in vitro. For the in vivo evaluation 30 million hMPCs expanded under growth conditions were infected with Ad-D2R, suspended in collagen type I (1mg/ml) and injected subcutaneously (8 weeks old, female nude mice). After 2 and 4 weeks the newly-formed muscle tissues were visualized by PET and harvested for autoradiography and histological analysis. Furthermore, histomorphometry of the isolated newly-formed muscle tissues was performed to access their functionality. RESULTS: The successful transduction of hMPCs allowed precise detection by PET Imaging in vitro. Further characterizations of their morphology after harvesting revealed no differences to non-transduced cells. These results confirm that using genetically modified hMPCs does not alter the muscle phenotype or contractility. The usage of PET imaging of our engineered muscle engrafts allows cell tracking after transplantation and non-invasively provides us with additional insights regarding their survival in vivo (via dopamine D2 receptor (DRD2) labeled hMPCs). Autoradiography also confirmed the presence of the transduced cells in the engineered tissue. CONCLUSIONS: The combination of a mutated D2-receptor and PET Imaging may offer a novel method for non-invasive visualization and detection of stem cells after injection for treatment of muscle diseases.