Extracellular vesicles (EVs) are lipid enveloped nanoparticles that are naturally produced by cells and function in the intercellular transfer of biological material such as proteins, RNAs and ...metabolites. They have been shown to act in an autocrine and paracrine manner to alter the functions of local and distant recipient cells, with a growing body of evidence highlighting their wide-ranging functions in regenerative processes such as stem cell maintenance, tissue repair and immune modulation. EVs offer several potential advantages over stem cell therapies such as improved safety profiles, scalability, and enhanced storage and quality control of the final product. In fact, many of the pro-regenerative outcomes of stem cell therapies have been attributed to the release of mesenchymal stem cell-derived EVs (MSC-EVs) and their potent effects on extracellular matrix turnover, local cell recruitment, proliferation and angiogenesis is now well described. These positive outcomes have led to clinical trials assessing the safety of MSC-EVs for applications in wound healing and the treatment of cutaneous ulcers, as well as the emergence of multiple commercial MSC-EV sources marketed for topical application in cosmetic medicine. However, regenerative EV therapeutics remain in their infancy and pertinent questions regarding product standardisation, potency and the regulatory landscape surrounding the development of these promising nano-therapeutics must be addressed to ensure safe and effective clinical adoption. In this article we provide an overview of the emerging landscape of MSC-EVs in regenerative dermatology and cosmetic science, highlighting the underlying biological mechanisms pertinent to their application and providing a perspective on current safety considerations, regulation and future directions in the field.
Display omitted
•MSC-EVs can elicit immunoregulatory, pro-angiogenic and anti-fibrotic effects.•Several companies are marketing MSC-EV products for topical dermal applications.•Pertinent questions remain concerning purity, dosage and degree of penetration.•Functionally relevant and rigorous potency assays will be required for widespread regulatory approval.•Application of EVs with existing modalities (e.g. microneedling, hydrogels) could enhance therapeutic efficacy.
Skeletal muscle (SkM) regenerates following injury, replacing damaged tissue with high fidelity. However, in serious injuries, non-regenerative defects leave patients with loss of function, increased ...re-injury risk and often chronic pain. Progress in treating these non-regenerative defects has been slow, with advances only occurring where a comprehensive understanding of regeneration has been gained. Tissue engineering has allowed the development of bioengineered models of SkM which regenerate following injury to support research in regenerative physiology. To date, however, no studies have utilised human myogenic precursor cells (hMPCs) to closely mimic functional human regenerative physiology.
Here we address some of the difficulties associated with cell number and hMPC mitogenicity using magnetic association cell sorting (MACS), for the marker CD56, and media supplementation with fibroblast growth factor 2 (FGF-2) and B-27 supplement. Cell sorting allowed extended expansion of myogenic cells and supplementation was shown to improve myogenesis within engineered tissues and force generation at maturity. In addition, these engineered human SkM regenerated following barium chloride (BaCl
) injury. Following injury, reductions in function (87.5%) and myotube number (33.3%) were observed, followed by a proliferative phase with increased MyoD+ cells and a subsequent recovery of function and myotube number. An expansion of the Pax7+ cell population was observed across recovery suggesting an ability to generate Pax7+ cells within the tissue, similar to the self-renewal of satellite cells seen in vivo.
This work outlines an engineered human SkM capable of functional regeneration following injury, built upon an open source system adding to the pre-clinical testing toolbox to improve the understanding of basic regenerative physiology.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Stem-cell-based therapies provide a biological basis for the regeneration of mineralised tissues. Stem cells isolated from adipose tissue (ADSCs), bone marrow (BMSCs) and dental pulp (DPSCs) have the ...capacity to form mineralised tissue. However, studies comparing the capacity of ADSCs with BMSCs and DPSCs for mineralised tissue engineering are lacking, and their ability to regenerate dental tissues has not been fully explored. Characterisation of the cells using fluorescence-activated cell sorting and semi-quantitative reverse transcription PCR for MSC markers indicated that they were immunophenotypically similar. Alizarin red (AR) staining and micro-computed tomography (µCT) analyses demonstrated that the osteogenic potential of DPSCs was significantly greater than that of BMSCs and ADSCs. Scanning electron microscopy and AR staining showed that the pattern of mineralisation in DPSC cultures differed from ADSCs and BMSCs, with DPSC cultures lacking defined mineralised nodules and instead forming a diffuse layer of low-density mineral. Dentine matrix components (DMCs) were used to promote dentinogenic differentiation. Their addition to cultures resulted in increased amounts of mineral deposited in all three cultures and significantly increased the density of mineral deposited in BMSC cultures, as determined by µCT analysis. Addition of DMCs also increased the relative gene expression levels of the dentinogenic markers dentine sialophosphoprotein and dentine matrix protein 1 in ADSC and BMSC cultures. In conclusion, DPSCs show the greatest potential to produce a comparatively high volume of mineralised matrix; however, both dentinogenesis and mineral volume was enhanced in ADSC and BMSC cultures by DMCs, suggesting that these cells show promise for regenerative dental therapies.
The application of extracellular vesicles (EVs) as natural delivery vehicles capable of enhancing tissue regeneration could represent an exciting new phase in medicine. We sought to define the ...capacity of EVs derived from mineralising osteoblasts (MO-EVs) to induce mineralisation in mesenchymal stem cell (MSC) cultures and delineate the underlying biochemical mechanisms involved. Strikingly, we show that the addition of MO-EVs to MSC cultures significantly (P < 0.05) enhanced the expression of alkaline phosphatase, as well as the rate and volume of mineralisation beyond the current gold-standard, BMP-2. Intriguingly, these effects were only observed in the presence of an exogenous phosphate source. EVs derived from non-mineralising osteoblasts (NMO-EVs) were not found to enhance mineralisation beyond the control. Comparative label-free LC-MS/MS profiling of EVs indicated that enhanced mineralisation could be attributed to the delivery of bridging collagens, primarily associated with osteoblast communication, and other non-collagenous proteins to the developing extracellular matrix. In particular, EV-associated annexin calcium channelling proteins, which form a nucleational core with the phospholipid-rich membrane and support the formation of a pre-apatitic mineral phase, which was identified using infrared spectroscopy. These findings support the role of EVs as early sites of mineral nucleation and demonstrate their value for promoting hard tissue regeneration.
Many small- and medium-sized mammals dig for their food. This activity potentially affects soil condition and fertility. Digging is well developed especially in Australian mammals, many of which have ...recently become rare or extinct. We measured the effects of digging by mammals on soil in a Tasmanian temperate dry sclerophyll forest with an intact mammal community. The density of diggings was 5812 ha
, affecting 11% of the forest floor. Diggings were created at a rate of around 3113 diggings ha
yr
, disturbing 6.5% of the forest floor and displacing 7.1 m
ha
of soil annually. Most diggings were made by eastern bettongs (
and short-beaked echidnas (
). Many (approx. 30%) fresh diggings consisted of re-excavations of old diggings. Novel diggings displaced 5 m
ha yr
of soil. Diggings acted as traps for organic matter and sites for the formation of new soil, which had higher fertility and moisture content and lower hardness than undisturbed topsoil. These effects on soil fertility and structure were strongest in habitats with dry and poor soil. Creation of fine-scaled heterogeneity by mammals, and amelioration of dry and infertile soil, is a valuable ecosystem service that could be restored by reintroduction of digging mammals to habitats from which they have declined or gone extinct.
We present an analysis of the diffuse emission at 5 GHz in the first quadrant of the Galactic plane using two months of preliminary intensity data taken with the C-Band All-Sky Survey (C-BASS) ...northern instrument at the Owens Valley Radio Observatory, California. Combining C-BASS maps with ancillary data to make temperature–temperature plots, we find synchrotron spectral indices of β = −2.65 ± 0.05 between 0.408 and 5 GHz and β = −2.72 ± 0.09 between 1.420 and 5 GHz for −10° < |b| < −4°, 20° < l < 40°. Through the subtraction of a radio recombination line free–free template, we determine the synchrotron spectral index in the Galactic plane (|b| < 4°) to be β = −2.56 ± 0.07 between 0.408 and 5 GHz, with a contribution of 53 ± 8 per cent from free–free emission at 5 GHz. These results are consistent with previous low-frequency measurements in the Galactic plane. By including C-BASS data in spectral fits, we demonstrate the presence of anomalous microwave emission (AME) associated with the H ii complexes W43, W44 and W47 near 30 GHz, at 4.4σ, 3.1σ and 2.5σ, respectively. The CORNISH (Co-Ordinated Radio ‘N’ Infrared Survey for High mass star formation) VLA 5-GHz source catalogue rules out the possibility that the excess emission detected around 30 GHz may be due to ultracompact H ii regions. Diffuse AME was also identified at a 4σ level within 30° < l < 40°, −2° < b < 2° between 5 and 22.8 GHz.
Environmental and endocrine factors have been implicated in the aetiology of recurrent abortion, with poorly understood roles. Luteal phase insufficiency marked with insufficient progesterone ...secretion has been reported.
To define the involvement of progesterone, trace metals, and Vitamin E in pregnant women with history of recurrent spontaneous abortion.
Convenience sampling method was used to recruit 69 pregnant women aged 21-41 years with gestational age of 0-20 weeks in this case-control study. Thirty five (cases) and thirty four (controls) had previous and no history of recurrent spontaneous abortion respectively. Demographic characteristics and 10 mls of blood samples were obtained from each subject. Serum obtained was used for the determination of progesterone, zinc, copper, selenium, iron, magnesium, manganese, chromium, lead, cadmium, and serum vitamin E by standard methods.
Results showed statistically significant decreases (p<0.05) in the serum zinc, copper, and vitamin E and a significant elevation (p<0.05) in the serum selenium, lead, and cadmium in cases compared with controls. Insignificant decrease (p=0.07) was observed in the serum progesterone when cases were compared with controls.
Results suggest that elevated serum heavy metals (cadmium and lead) and reduction of essential micronutrients (zinc, copper and vitamin E) may contribute to recurrent spontaneous abortion.
The effects of cryopreservation on mesenchymal stem cell (MSC) phenotype are not well documented; however this process is of increasing importance for regenerative therapies. This study examined the ...effect of cryopreservation (10% dimethyl-sulfoxide) on the morphology, viability, gene-expression and relative proportion of MSC surface-markers on cells derived from rat adipose, bone marrow and dental pulp. Cryopreservation significantly reduced the number of viable cells in bone marrow and dental pulp cell populations but had no observable effect on adipose cells. Flow cytometry analysis demonstrated significant increases in the relative expression of MSC surface-markers, CD90 and CD29/CD90 following cryopreservation. sqRT-PCR analysis of MSC gene-expression demonstrated increases in pluripotent markers for adipose and dental pulp, together with significant tissue-specific increases in CD44, CD73–CD105 following cryopreservation. Cells isolated from different tissue sources did not respond equally to cryopreservation with adipose tissue representing a more robust source of MSCs.
The collagen molecule, which is the building block of collagen fibrils, is a triple helix of two α1(I) chains and one α2(I) chain. However, in the severe mouse model of osteogenesis imperfecta (OIM), ...deletion of the COL1A2 gene results in the substitution of the α2(I) chain by one α1(I) chain. As this substitution severely impairs the structure and mechanics of collagen-rich tissues at the tissue and organ level, the main aim of this study was to investigate how the structure and mechanics are altered in OIM collagen fibrils. Comparing results from atomic force microscopy imaging and cantilever-based nanoindentation on collagen fibrils from OIM and wild-type (WT) animals, we found a 33% lower indentation modulus in OIM when air-dried (bound water present) and an almost fivefold higher indentation modulus in OIM collagen fibrils when fully hydrated (bound and unbound water present) in phosphate-buffered saline solution (PBS) compared with WT collagen fibrils. These mechanical changes were accompanied by an impaired swelling upon hydration within PBS. Our experimental and atomistic simulation results show how the structure and mechanics are altered at the individual collagen fibril level as a result of collagen gene mutation in OIM. We envisage that the combination of experimental and modelling approaches could allow mechanical phenotyping at the collagen fibril level of virtually any alteration of collagen structure or chemistry.
Heterotopic ossification (HO) is a debilitating condition defined by the de novo development of bone within non-osseous soft tissues, and can be either hereditary or acquired. The hereditary ...condition, fibrodysplasia ossificans progressiva is rare but life threatening. Acquired HO is more common and results from a severe trauma that produces an environment conducive for the formation of ectopic endochondral bone. Despite continued efforts to identify the cellular and molecular events that lead to HO, the mechanisms of pathogenesis remain elusive. It has been proposed that the formation of ectopic bone requires an osteochondrogenic cell type, the presence of inductive agent(s) and a permissive local environment. To date several lineage-tracing studies have identified potential contributory populations. However, difficulties identifying cells in vivo based on the limitations of phenotypic markers, along with the absence of established in vitro HO models have made the results difficult to interpret. The purpose of this review is to critically evaluate current literature within the field in an attempt identify the cellular mechanisms required for ectopic bone formation. The major aim is to collate all current data on cell populations that have been shown to possess an osteochondrogenic potential and identify environmental conditions that may contribute to a permissive local environment. This review outlines the pathology of endochondral ossification, which is important for the development of potential HO therapies and to further our understanding of the mechanisms governing bone formation.
PDF
