Synthesis and fabrication of porous and elastomeric nanocomposite scaffolds from biodegradable poly(glycerol sebacate) (PGS) and osteoinductive nanosilicates is reported. Nanosilicates are ...mineral-based two-dimensional (2D) nanomaterials with high surface area which reinforced PGS network. The addition of nanosilicates to PGS resulted in mechanically stiff and elastomeric nanocomposites. The degradation rate and mechanical stiffness of nanocomposite network could be modulated by addition of nanosilicates. Nanocomposite scaffolds supported cell adhesion, spreading, and proliferation and promoted osteogenic differentiation of preosteoblasts. The addition of nanosilicates to PGS scaffolds increased alkaline phosphatase (ALP) activity and production of matrix mineralization. In vivo studies demonstrated biocompatibility and biodegradability of nanocomposite scaffolds. Overall, the combination of elasticity and tailorable stiffness, tunable degradation profiles, and the osteoinductive capability of the scaffolds offer a promising approach for bone tissue engineering.
The majority of cancer patients experience dramatic weight loss, due to cachexia and consisting of skeletal muscle and fat tissue wasting. Cachexia is a negative prognostic factor, interferes with ...therapy and worsens the patients' quality of life by affecting muscle function. Mice bearing ectopically-implanted C26 colon carcinoma are widely used as an experimental model of cancer cachexia. As part of the search for novel clinical and basic research applications for this experimental model, we characterized novel cellular and molecular features of C26-bearing mice.
A fragment of C26 tumor was subcutaneously grafted in isogenic BALB/c mice. The mass growth and proliferation rate of the tumor were analyzed. Histological and cytofluorometric analyses were used to assess cell death, ploidy and differentiation of the tumor cells. The main features of skeletal muscle atrophy, which were highlighted by immunohistochemical and electron microscopy analyses, correlated with biochemical alterations. Muscle force and resistance to fatigue were measured and analyzed as major functional deficits of the cachectic musculature.
We found that the C26 tumor, ectopically implanted in mice, is an undifferentiated carcinoma, which should be referred to as such and not as adenocarcinoma, a common misconception. The C26 tumor displays aneuploidy and histological features typical of transformed cells, incorporates BrdU and induces severe weight loss in the host, which is largely caused by muscle wasting. The latter appears to be due to proteasome-mediated protein degradation, which disrupts the sarcomeric structure and muscle fiber-extracellular matrix interactions. A pivotal functional deficit of cachectic muscle consists in increased fatigability, while the reported loss of tetanic force is not statistically significant following normalization for decreased muscle fiber size.
We conclude, on the basis of the definition of cachexia, that ectopically-implanted C26 carcinoma represents a well standardized experimental model for research on cancer cachexia. We wish to point out that scientists using the C26 model to study cancer and those using the same model to study cachexia may be unaware of each other's works because they use different keywords; we present strategies to eliminate this gap and discuss the benefits of such an exchange of knowledge.
Effective clinical treatments for volumetric muscle loss resulting from traumatic injury or resection of a large amount of muscle mass are not available to date. Tissue engineering may represent an ...alternative treatment approach. Decellularization of tissues and whole organs is a recently introduced platform technology for creating scaffolding materials for tissue engineering and regenerative medicine. The muscle stem cell niche is composed of a three-dimensional architecture of fibrous proteins, proteoglycans, and glycosaminoglycans, synthesized by the resident cells that form an intricate extracellular matrix (ECM) network in equilibrium with the surrounding cells and growth factors. A consistent body of evidence indicates that ECM proteins regulate stem cell differentiation and renewal and are highly relevant to tissue engineering applications. The ECM also provides a supportive medium for blood or lymphatic vessels and for nerves. Thus, the ECM is the nature's ideal biological scaffold material. ECM-based bioscaffolds can be recellularized to create potentially functional constructs as a regenerative medicine strategy for organ replacement or tissue repopulation. This article reviews current strategies for the repair of damaged muscle using bioscaffolds obtained from animal ECM by decellularization of small intestinal submucosa (SIS), urinary bladder mucosa (UB), and skeletal muscle, and proposes some innovative approaches for the application of such strategies in the clinical setting.
Severe COVID-19 is associated with a high circulating level of calprotectin, the S100A8/S100A9 alarmin heterodimer. Baseline calprotectin amount measured in peripheral blood at diagnosis correlates ...with disease severity. The optimal use of this biomarker along COVID-19 course remains to be delineated.
We focused on patients with a WHO-defined moderate COVID-19 requiring hospitalization in a medical ward. We collected plasma and serum from three independent cohorts (N = 626 patients) and measured calprotectin amount at admission. We performed longitudinal measures of calprotectin in 457 of these patients (1461 samples) and used a joint latent class mixture model in which classes were defined by age, body mass index and comorbidities to identify calprotectin trajectories predicting the risk of transfer into an intensive care unit or death.
After adjustment for age, sex, body mass index and comorbidities, the predictive value of baseline calprotectin in patients with moderate COVID19 could be refined by serial monitoring of the biomarker. We discriminated three calprotectin trajectories associated with low, moderate, and high risk of poor outcome, and we designed an algorithm available as online software (https://calpla.gustaveroussy.fr:8443/) to monitor the probability of a poor outcome in individual patients with moderate COVID-19.
These results emphasize the clinical interest of serial monitoring of calprotectin amount in the peripheral blood to anticipate the risk of poor outcomes in patients with moderate COVID-19 hospitalized in a standard care unit.
The study received support (research grants) from ThermoFisher immunodiagnostics (France) and Gustave Roussy Foundation.
Although static magnetic fields (SMFs) are used extensively in the occupational and medical fields, few comprehensive studies have investigated their possible genotoxic effect and the findings are ...controversial. With the advent of magnetic resonance imaging-guided radiation therapy, the potential effects of SMFs on ionizing radiation (IR) have become increasingly important. In this study we focused on the genotoxic effect of 80 mT SMFs, both alone and in combination with (i.e. preceding or following) X-ray (XR) irradiation, on primary glioblastoma cells in culture. The cells were exposed to: (i) SMFs alone; (ii) XRs alone; (iii) XR, with SMFs applied during recovery; (iv) SMFs both before and after XR irradiation. XR-induced DNA damage was analyzed by Single Cell Gel Electrophoresis assay (comet assay) using statistical tools designed to assess the tail DNA (TD) and tail length (TL) as indicators of DNA fragmentation. Mitochondrial membrane potential, known to be affected by IR, was assessed using the JC-1 mitochondrial probe. Our results showed that exposure of cells to 5 Gy of XR irradiation alone led to extensive DNA damage, which was significantly reduced by post-irradiation exposure to SMFs. The XR-induced loss of mitochondrial membrane potential was to a large extent averted by exposure to SMFs. These data suggest that SMFs modulate DNA damage and/or damage repair, possibly through a mechanism that affects mitochondria.
The continuous introduction of new antineoplastic drugs and their use as complex mixture emphasize the need to carry out correct health risk assessment. The aim of this study was to evaluate ...genotoxic effects of antineoplastic drugs in nurses (
n
=
25) and pharmacy technicians (
n
=
5) employed in an oncology hospital. The nurses administered antineoplastic drugs in the day-care hospital (
n
=
12) and in the wards (
n
=
13), and pharmacy technicians prepared the drugs in the central pharmacy. We performed the micronucleus (MN) test with lymphocytes and exfoliated buccal cells and conducted traditional analysis of chromosomal aberrations (CA). Thirty healthy subjects were selected as controls. Monitoring of surface contamination with cyclophosphamide, 5-fluorouracil, ifosfamide, cytarabine, and gemcitabine showed the presence of detectable levels only for cyclophosphamide, 5-fluorouracil and ifosfamide. In addition, we measured the 5-fluorouracil metabolite α-F-βalanine in the urine of all subjects and found significant concentrations only in 3 out of 25 nurses. The micronucleus assay with lymphocytes did not show significant differences between exposed and control groups, while the same test with exfoliated buccal cells found higher values in nurses administering antineoplastic drugs than in pharmacy employees. In the CA analysis, we detected in exposed groups a significant increase (about 2.5-fold) of structural CA, particularly breaks (up to 5.0-fold). Our results confirm the genotoxic effect of antineoplastic drugs in circulating blood lymphocytes. Moreover, in exfoliated buccal cells the data show more consistent genetic damage induced during administration of the antineoplastic drugs than during their preparation. The data also stress the use of this non-invasive sampling, to assess occupational exposure to mixture of chemicals at low doses.
Abstract In the pursuit of a transplantable construct for the replacement of large skeletal muscle defects arising from traumatic or pathological conditions, several attempts have been made to obtain ...a highly oriented, vascularized and functional skeletal muscle. Acellular scaffolds derived from organ decellularization are promising, widely used biomaterials for tissue engineering. However, the acellular skeletal muscle extra cellular matrix (ECM) has been poorly characterized in terms of production, storage and host–donor interactions. We have produced acellular scaffolds at the whole organ scale from various skeletal muscles explanted from mice. The acellular scaffolds conserve chemical and architectural features of the tissue of origin, including the vascular bed. Scaffolds can be sterilely stored for weeks at +4 °C or +37 °C in tissue culture grade conditions. When transplanted in wt mice, the grafts are stable for several weeks, whilst being colonized by inflammatory and stem cells. We demonstrate that the acellular scaffold per se represents a pro-myogenic environment supporting de novo formation of muscle fibers, likely derived from host cells with myogenic potential. Myogenesis within the implant is enhanced by immunosuppressive treatment. Our work highlights the fundamental role of this niche in tissue engineering application and unveils the clinical potential of allografts based on decellularized tissue for regenerative medicine.
To determine the effects of 10 years of enzyme replacement therapy (ERT) in adult patients with Pompe disease, focusing on individual variability in treatment response.
In this prospective, ...multicenter cohort study, we studied 30 patients from the Netherlands and France who had started ERT during the only randomized placebo-controlled clinical trial with ERT in late-onset Pompe disease (NCT00158600) or its extension (NCT00455195) in 2005 to 2008. Main outcomes were walking ability (6-minute walk test 6MWT), muscle strength (manual muscle testing using Medical Research Council MRC grading), and pulmonary function (forced vital capacity FVC in the upright and supine positions), assessed at 3- to 6-month intervals before and after the start of ERT. Data were analyzed with linear mixed-effects models for repeated measurements.
Median follow-up duration on ERT was 9.8 years (interquartile range IQR 8.3-10.2 years). At the group level, baseline 6MWT was 49% of predicted (IQR 41%-60%) and had deteriorated by 22.2 percentage points (pp) at the 10-year treatment point (
< 0.001). Baseline FVC upright was 54% of predicted (IQR 47%-68%) and decreased by 11 pp over 10 years (
< 0.001). Effects of ERT on MRC sum score and FVC supine were similar. At the individual level, 93% of patients had initial benefit of ERT. Depending on the outcome measured, 35% to 63% of patients had a secondary decline after ≈3 to 5 years. Still, at 10 years of ERT, 52% had equal or better 6MWT and/or FVC upright compared to baseline.
The majority of patients with Pompe disease benefit from long-term ERT, but many patients experience some secondary decline after ≈3 to 5 years. Individual variation, however, is considerable.
This study provides Class IV evidence that for the majority of adults with Pompe disease, long-term ERT positively affects, or slows deterioration in, muscle strength, walking ability, and/or pulmonary function.
The introduction of man-made vitreous fibers (MMVFs) as a substitute for asbestos in industrial and residential applications raises concerns about their potential health hazards. The aim of our study ...was to assess cytotoxic and oxidative effects induced on a human mesothelial cell line (MeT-5A) by exposure to glass wool (GW), rock wool (RW) and refractory ceramic fibers (RCF) in comparison with crocidolite asbestos (CR). MeT-5A cells were exposed for 24
h to 2, 5 and 10
μg/cm
2 of MMVF and crocidolite fibers and analysed by scanning electron microscope (SEM) for cell surface alterations. Cells were exposed for 2
h to 1, 2, 5 and 10
μg/cm
2 of the same fibers and analysed by enzyme Fpg-modified comet test for direct and oxidative DNA damage. SEM revealed loss of microvilli in cells exposed to RCF and numerous blebs in cells exposed to higher doses of RW. Comet test showed significant direct DNA damage in cells exposed to RCF even at the lowest dose. Comet test with Fpg, that permits the detection of oxided DNA bases, showed significant oxidative DNA damage in cells exposed to higher doses of RW. The presence of DNA damage and alterations of cell surface induced by low doses of RCF and the presence of oxidative DNA damage and blebs on cell surface in cells exposed to higher dose of RW suggest possible cytotoxic, oxidative and genotoxic effects for these MMVFs.
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