Opportunities For Regeneration Research Articles

Regeneration dynamics in arid subtropical thicket, South Africa

In arid environments nurse-plants modify localised habitats and create regeneration opportunities for seedlings vulnerable to hostile conditions created by biotic and abiotic factors. Facilitation is thus recognised as an important process structuring plant communities in harsh environments. Here we use spatial patterns of species association and recruitment to infer species replacement patterns in arid subtropical thicket of South Africa. Although our study site was floristically impoverished, all major plant functional groups that characterise subtropical thicket were present. Portulacaria afra clumps comprised approximately 50% of the study site by area. The mean and median clump size was 16.5 and 6.9m2, respectively, indicating the prevalence of small individuals in the population. Approximately 90% of tree seedlings were recorded under P. afra clumps and 93% of P. afra seedlings were recorded under woody shrubs. P. afra seedlings were recorded more frequently than expected beneath Rhigozum obovatum compared with other woody shrub species. No clear recruitment patterns were recorded for R. obovatum. Lycium cinereum, a woody shrub, and the stem-succulent Psilocaulon absimile were distributed more frequently on nutrient rich patches than expected and both these species are replaced by grass as the nutrient rich patch ages. Mature trees were generally recorded growing to the south of the assumed founding P. afra stem indicating that tree establishment was more frequent on the shaded side of P. afra clumps. However, most trees grew towards the sunny north and east-facing aspects. Plant species replacement patterns are facilitated by nurse-plant effects in arid subtropical thicket. These recruitment patterns together with our inferred species replacement on nutrient rich patches result in a predictable sequence of species replacement that is cyclic in nature.

Clay: New Opportunities for Tissue Regeneration and Biomaterial Design

Seminal recent studies that have shed new light on the remarkable properties of clay interactions suggest unexplored opportunities for biomaterial design and regenerative medicine. Here, recent conceptual and technological developments in the science of clay interactions with biomolecules, polymers, and cells are examined, focusing on the implications for tissue engineering and regenerative strategies. Pioneering studies demonstrating the utility of clay for drug-delivery and scaffold design are reviewed and areas for future research and development highlighted.

Neurosteroids as regenerative agents in the brain: therapeutic implications.

Regenerative therapeutics hold the promise of self-renewal and repair. Ageing and age-associated neurodegenerative diseases are marked by a decline in self-renewal and repair, but a capacity for regeneration is retained. The challenge faced by researchers developing molecular therapeutics to promote self-renewal in the nervous system is to activate regenerative and repair pathways often in the context of progressive degeneration. Neurosteroids regulate both regeneration and repair systems in the brain, and among this class of molecules, allopregnanolone has been broadly investigated for its role to promote regeneration in both the central and peripheral nervous systems. In the brain, allopregnanolone induced generation and survival of new neurons in the hippocampus of both aged mice and mice with Alzheimer disease, accompanied by restoration of associative learning and memory function. In the brain of mice with Alzheimer disease, allopregnanolone increased liver X receptor and pregnane X receptor expression, reduced amyloid-β and microglial activation, and increased markers of myelin and white matter generation. Therapeutic windows for efficacy of allopregnanolone were evident in the brains of mice with both normal ageing and Alzheimer disease. Allopregnanolone dose and a regenerative treatment regimen of intermittent allopregnanolone exposure were determining factors regulating therapeutic efficacy. Allopregnanolone serves as proof of concept for therapeutics that target endogenous regeneration, windows of therapeutic opportunity for regeneration, and critical system biology factors that will determine the efficacy of regeneration.

Restoring forest resilience: From reference spatial patterns to silvicultural prescriptions and monitoring

Stand-level spatial pattern influences key aspects of resilience and ecosystem function such as disturbance behavior, regeneration, snow retention, and habitat quality in frequent-fire pine and mixed-conifer forests. Reference sites, from both pre-settlement era reconstructions and contemporary forests with active fire regimes, indicate that frequent-fire forests are complex mosaics of individual trees, tree clumps, and openings. There is a broad scientific consensus that restoration treatments should seek to restore this mosaic pattern in order to restore resilience and maintain ecosystem function. Yet, methods to explicitly incorporate spatial reference information into restoration treatments are not widely used. In addition, targets from reference conditions must be critically evaluated in light of climate change. We used a spatial clump identification algorithm to quantify reference patterns based on a specified inter-tree distance that defines when trees form clumps. We used climatic water balance parameters, downscaled climate projections, and plant associations to assess our historical reference sites in the context of projected future climate and identify climate analog reference conditions. Spatial reference information was incorporated into a novel approach to prescription development, tree marking, and monitoring based on viewing stand structure and pattern in terms of individuals, clumps, and openings (ICO) in a mixed-conifer forest restoration case study. We compared the results from the ICO approach with simulations of traditional basal area and spacing-based thinning prescriptions in terms of agreement with reference conditions and functional aspects of resilience. The ICO method resulted in a distribution of tree clumps and openings within the range of reference patterns, while the basal area and spacing approaches resulted in uniform patterns inconsistent with known reference conditions. Susceptibility to insect mortality was lower in basal area and spacing prescriptions, but openings and corresponding opportunities for regeneration and in situ climate adaptation were fewer. Operationally, the method struck a balance between providing clear targets for spatial pattern directly linked to reference conditions, sufficient flexibility to achieve other restoration objectives, and implementation efficiency. The need to track pattern targets during implementation and provide immediate feedback to marking crews was a key lesson. The ICO method, especially when used in combination with climate analog reference targets, offers a practical approach to restoring spatial patterns that are likely to enhance resilience and climate adaptation.

Role of Anisotropy in Tissue Engineering

Tissue engineering is a highly interdisciplinary field that requires the integrated expertise of clinicians, cell biologists, engineers and material scientists, to make progress in the development and deployment of biological substitutes that restore, maintain, or improve tissue function. The purpose is to provide the opportunities for tissue regeneration and organ replacement. Key advances in biological materials especially in the area of stem cells; growth and differentiation factors generate realistic opportunities to create tissues in the laboratory using an engineered extracellular matrix or scaffold and biologically active molecules. The scaffold acts as an artificial extracellular matrix and it needs to mimic the chemical composition and physical architecture of natural extracellular matrix to facilitate cell adhesion, proliferation, differentiation and new tissue formation. In this contribution we review the role of the scaffold system in promoting cell adhesion, proliferation and differentiation with respect to the anisotropic nature of the scaffold system. We address both the anisotropy which may exist at a microscopic or mesoscopic scale, for example the shape of pores as well as the molecular level interactions which may arise in a scaffold containing a molecular organization with a preferred orientation which may have been induced during the processing procedures used to prepare the scaffold. Of course some approaches to the preparation of scaffolds systems are inherently anisotropic, for example the wide-spread utilization of meshes prepared by electrospinning. In other words although the overall scaffold is isotropic, the basic elements in terms of an electrospun fibre is highly anisotropic in terms of its external form and possibly in terms of its internal structure. By reviewing the possible advantages of the inclusion of anisotropic elements in the scaffold we add to the knowledge base which allows scaffolds design to be optimised for specific tissue growth.

The Use of Enzymatic Hydrolyzate of Chlorophytum Comosum with Experimental Toxic Liver Damage in Rats

Investigation of the influence of the enzymatic hydrolyzate of Chlorophytum comosumthe first on the liver of rats at its toxic damage showed that the substrate has expressed a pronounced hepatoprotective effect. Under its influence in the rat liver morphological changes induced by CCl4 are much less pronounced than in the controls. There are also less significant deviations from normal levels of ALT, AST and bilirubin. Information analysis of the state of the organ indicates that the level of adaptation and regeneration opportunities of the liver of rats treated with an enzymatic hydrolyzate of Chlorophytum comosum is significantly higher than that of the liver of rats with experimental toxic liver damage without the use of tested substrate.

Protective Effect of Enzymatic Hydrolyzate of Chlorophytum Comosum (L.) against Experimental Toxic Liver Injury in Wistar Rats at the Age of Two Years

Researches of age-dependent changes of liver functions and their correction with the use of various biologically active substances are an important issue of modern biomedicine. Investigation of the influence of the enzymatic hydrolyzate of Chlorophytum comosum (L.) on the liver of rats at the age of two years at its experimental toxic damage showed that the substrate has expressed a pronounced hepatoprotective effect. Under its influence morphological changes in the rat liver induced by CCl4 are much less pronounced than in the controls. There are also less significant deviations from normal levels of Alanine transamilase (ALT), Alanine transaminase AST and Total Bilirubin in blood plasma. Information analysis of the state of the organ indicates that the level of adaptation and regeneration opportunities of the liver of rats treated with an enzymatic hydrolyzate of Chlorophytum comosum (L.) is significantly higher than at the liver of rats with experimental toxic liver damage without the use of studied substrate. Histopathological analysis confirmed the alleviation of liver damage in connection with use of enzymatic hydrolyzate of Chlorophytum comosum (L.)

Duff mound consumption and cambium injury for centuries-old western larch from prescribed burning in western Montana

Western larch is one of the most fire-adapted conifers in western North America. Its historical perpetuation depended upon regular fire disturbances, which creates open stand conditions and mineral seedbeds. A stand of 200- to 500-year-old larch in western Montana with deep duff mounds resulting from an unusually long 150-year fire-free period was mechanically thinned and prescribed burned to reduce the probability of high intensity wildfire near a community and increase opportunities for larch regeneration. Little documentation is available regarding basal damage to larch from lengthy duff mound burning; therefore this study was established to assess: duff consumption from prescribed burning and resulting cambial damage and tree vitality. Ninety trees averaging 91-cm diameter at breast height were selected, half with duff mounds measured and burned in autumn and half with mounds removed. Duff depths nearest the bole averaged 20 cm and mound consumption approached 100% including large amounts of the basal bark with smouldering combustion lasting 18–24 h. Cambial mortality ranged from 0 to 36% of the basal circumference but no trees had died after 7 years. The cambium mortality was likely due to the spatially infrequent coincident of deep duff and thinner bark. Under similar site and environmental conditions removal of the potential duff consumption injury hazard appears unwarranted.

Spatial distribution of saplings in heavily worn urban forests: Implications for regeneration and management

We studied the spatial distribution of saplings in the vicinity of other saplings and mature trees in heavily worn urban forests. Our aim was to identify favorable microsites for saplings to regenerate under different levels of wear. We hypothesized that these safe microsites were situated close to tree trunks that might offer shelter from trampling caused by humans and their pet dogs. The distribution of saplings was explored at 0.1–0.6m to the nearest sapling and 0.1–2m to the nearest mature tree. Sorbus aucuparia was the most abundant sapling species, followed by Populus tremula, Betula pubescens and Picea abies. These species all tended to cluster with their conspecific saplings and were generally randomly distributed with respect to mature trees. Saplings of S. aucuparia and P. tremula favored growing close to mature P. abies (already at 0.4–0.8 up to 2m from the trunk base, respectively) and S. aucuparia trees (at 0.2–0.4m up to 2m). Betula sp. and Acer platanoides grew close to Pinus sylvestris trees. Furthermore, with increased levels of wear, saplings clustered more likely together and close to tree trunks. The results are contrary to the gap regeneration hypothesis known from rural unworn forests where saplings often grow in canopy gaps. We suggest the idea of a ‘sheltering group’, i.e. tree groups and thickets of densely growing conspecific saplings, for the maintenance of regeneration of saplings and other vegetation in heavily worn recreational forests. Since urban forestry may strongly affect the existence and spatial location of a high variety of microhabitats, small-scale spatial exploration is needed to identify microsites that offer opportunities for natural regeneration under heavy recreational use. To maintain natural regeneration and the survival of saplings in worn urban forests, we recommend microhabitat-level species-specific forest management.

City-making. Occasioni di rigenerazione urbana

Urban transformation resulting from the reutilization of urban areas located close to historical consolidated areas, formerly occupied by industrial complexes, settled at the end of the nineteenth century (and now abandoned) and by disued military areas, represent a great opportunity for regeneration and urban renewal, in order to balance the physical and functional structure of the existing city. Mostly there areas are real voids to be returned to the city, assigning new functions, catalyst of differente activities and generatior of a substantial housing income, and defining new spaces, both for public and private use, aimed at combining social and collective urban interaction.

Injectable polyurethane composite scaffolds delay wound contraction and support cellular infiltration and remodeling in rat excisional wounds

Injectable scaffolds present compelling opportunities for wound repair and regeneration because of their ability to fill irregularly shaped defects and deliver biologics such as growth factors. In this study, we investigated the properties of injectable polyurethane (PUR) biocomposite scaffolds and their application in cutaneous wound repair using a rat excisional model. The scaffolds have a minimal reaction exotherm and clinically relevant working and setting times. Moreover, the biocomposites have mechanical and thermal properties consistent with rubbery elastomers. In the rat excisional wound model, injection of settable biocomposite scaffolds stented the wounds at early time points, resulting in a regenerative rather than a scarring phenotype at later time points. Measurements of wound length and thickness revealed that the treated wounds were less contracted at day 7 compared to blank wounds. Analysis of cell proliferation and apoptosis showed that the scaffolds were biocompatible and supported tissue ingrowth. Myofibroblast formation and collagen fiber organization provided evidence that the scaffolds have a positive effect on extracellular matrix remodeling by disrupting the formation of an aligned matrix under elevated tension. In summary, we have developed an injectable biodegradable PUR biocomposite scaffold that enhances cutaneous wound healing in a rat model.

Heparin Mimetic Peptide Nanofibers Promote Angiogenesis

New blood vessel formation (angiogenesis) is one of the most important processes required for functional tissue formation. Induction of angiogenesis is usually triggered by growth factors released by cells. Glycosaminoglycans (e.g., heparan sulphates) in the extracellular matrix aid in proper functioning of these growth factors. Therefore, exogeneous heparin or growth factors were required for promoting angiogenesis in previous regenerative medicine studies. Here we report for the first time induction of angiogenesis by a synthetic nanofibrous peptide scaffold without the addition of any exogenous growth factors or heparin. We designed and synthesized a self-assembling peptide amphiphile molecule that is functionalized with biologically active groups to mimic heparin. Like heparin, this molecule has the ability to interact with growth factors and effectively enhance their bioactivity. The nanofibers formed by these molecules were shown to form a 3D network mimicking the structural proteins in the extracellular matrix. Because of heparin mimicking capabilities of the peptide nanofibers, angiogenesis was induced without the addition of exogenous growth factors in vitro. Bioactive interactions between the nanofibers and the growth factors enabled robust vascularization in vivo as well. Heparin mimetic peptide nanofibers presented here provide new opportunities for angiogenesis and tissue regeneration by avoiding the use of heparin and exogenous growth factors. The synthetic peptide nanofiber scaffolds enriched with proper chemical functional groups shown in this study can be used to induce various desired physiological responses for tissue regeneration.

Understory bamboo flowering provides a very narrow light window of opportunity for canopy-tree recruitment in a neotropical forest of Misiones, Argentina

Chusquea ramosissima is a native monocarpic bamboo species growing in subtropical forests of northeastern Argentina, which can dominate gaps and open forests in the region, particularly after human disturbance. This bamboo species started to flower in different areas of northeastern Argentina in 2001, with the flowering peak during 2002 and 2003 and small isolated flowering events still occurring until 2010. We studied the effects of C. ramosissima flowering and die-back on microclimate, litter decomposition, nutrient availability, sapling growth, abundance and regeneration of tree canopy species. We wanted to know how environmental conditions and ecosystem processes change through time after bamboo flowering and if bamboo die-back would favor regeneration of canopy trees. Twenty 50 × 50 m plots of flowering and non-flowering bamboo were permanently marked and vegetation dynamics as well as nutrient cycling and microclimate studies were performed. C. ramosissima die-back enhanced growth and reduced mortality rate of tree saplings during the first year after flowering. Only growth of tree saplings previously established was enhanced by the flowering event and tree-species richness and saplings abundance of canopy trees did not change as expected due to bamboo flowering. The short-term effect of tree saplings growth was likely due to incident solar radiation at the forest floor which doubled in the first year after the bamboo flowering event. Increased light availability at the forest floor simultaneously promoted the growth of other understory plants such as ferns, lianas and Piper spp. that rapidly colonized gaps and intercepted a percentage of the incident solar radiation after the first year, which together with an increased litter layer due to the senescence of the bamboo, may have inhibited establishment of new tree individuals and affected tree growth. Contrary to predictions, soil water, litter decomposition and soil nutrients were not significantly affected by bamboo flowering. Thus, successful tree regeneration in gaps following bamboo flowering appears to be restricted to a very narrow window of increased light availability (i.e., 1 year) before growth of other understory plants and rapid re-colonization of bamboo. Changes in resource availability, and the opportunity for overstory regeneration after bamboo flowering events appears to depend on climatic and community characteristics of the ecosystem where the flowering event occurs and also, on the flowering patterns and their synchronicity.

Recent Patents on Nanostructured Scaffolds for Bone Tissue Repair and Regeneration

Bone tissue engineering, which typically involves the assembly of bone structures by combining bone cells and scaffolds, offers a promising opportunity for bone regeneration in a natural way. Hence the scaffold is one of the most crucial factors to determine the fate of osteogenesis in bone repair and regeneration. This article made a review on the progress of scaffolds and substitutes with various nanostructures for bone repair according to recent patents. The aspects mainly include nanofibrous composites as scaffolds, nanostructured scaffolds composed of biological materials, method to create connective porous nanostructured composite scaffold, nanostructured surface of medical device for bone implants, nanostructured composites from decellularized natural tissue, nanofiber reinforcement composite, and spray drying technology for preparing nanostructured bioactive materials.

Recent Patents on Nanostructured Scaffolds for Bone Tissue Repair and Regeneration

Bone tissue engineering, which typically involves the assembly of bone structures by combining bone cells and scaffolds, offers a promising opportunity for bone regeneration in a natural way. Hence the scaffold is one of the most crucial factors to determine the fate of osteogenesis in bone repair and regeneration. This article made a review on the progress of scaffolds and substitutes with various nanostructures for bone repair according to recent patents. The aspects mainly include nanofibrous composites as scaffolds, nanostructured scaffolds composed of biological materials, method to create connective porous nanostructured composite scaffold, nanostructured surface of medical device for bone implants, nanostructured composites from decellularized natural tissue, nanofiber reinforcement composite, and spray drying technology for preparing nanostructured bioactive materials.

Mesenchymal stem cells as a therapeutic tool in tissue and organ regeneration

Tissue engineering is an interdisciplinary field that offers new opportunities for regeneration of diseased and damaged tissue with the use of many different cell types,including adult stem cells. In tissue engineering and regenerative medicine the most popular are mesenchymal stem cells (MSCs) isolated from bone marrow. Bone marrow mesenchymal stem cells are a potential source of progenitor cells for osteoblasts, chondroblasts, adipocytes, skeletal muscles and cardiomyocytes. It has also been shown that these cells can differentiate into ecto- and endodermal cells, e.g. neuronal cells, glial cells, keratinocytes and hepatocytes. The availability of autologous MSCs, their proliferative potential and multilineage differentiation capacity make them an excellent tool for tissue engineering and regenerative medicine. The aim of this publication is to present characteristic and biological properties of mesenchymal stem cells isolated from bone marrow.

Assessing the potential of railway station redevelopment in urban regeneration policies: an Italian case study

When we talk about urban sustainability, also mobility and transportation systems acquire a leading part to guarantee high levels of efficiency and livability of urban and metropolitan systems. Nowadays, railway transport networks represent essential frames to assure accessibility and reduction of traffic pollution and congestion, as well as they provide opportunities for urban regeneration. Recently, in Europe, railway stations have assumed a strategic role in urban redevelopments to provide efficient and livable urban and metropolitan systems but it's also necessary to have effective tools to achieve transport and urban goals at the same time. This paper illustrates an analytical and evaluation method to assess the renewal redevelopment potential of great rail stations and the spatial and urban regeneration opportunities that follow. The methodology has been implemented by its application to two Italian rail station redevelopments.

Re-use of derelict industrial sites: Opportunities for regeneration of industrial heritage in Pancevo, Serbia

Subject of the paper is industrial heritage and its regeneration. Emphasis has been put on industrial objects that have lost their primary function and now have historical, social and architectural value. Condition and problems of industrial heritage were discussed through the example of Pancevo, one of the first and biggest industrial cities in Serbia. Aim was to examine the current policy and practice in redevelopment and investigate in which way and to what extent can good examples from the international practice be applied to Pancevo. Findings of the research are given through set of recommendations, discussed through four themes: 1) culture-led regeneration - development of cultural activities in former industrial buildings, 2) industrial heritage as a tool for improving the ecological image of the city, 3) industrial heritage as a potential for development of tourism, 4) heritage as a potential for economic development. Value of paper lies in drawing attention on significance of the industrial heritage and problem of its dereliction, and investigation of application of international models on Serbian situation. As one of the biggest industrial cities in the region, Pancevo can serve as a model not only for Serbia, but also for cities in other countries that are in similar situation.

Assessing the potential for ash canopy tree replacement via current regeneration following emerald ash borer-caused mortality on southeastern Michigan landscapes

The emerald ash borer (EAB) has killed millions of ash trees in Michigan and at least fourteen other states since its first detection near its introduction point in metropolitan Detroit in 2002. Despite overstory ash mortality near 100% in many areas, ash seedling and saplings remain unaffected and provide the potential for ash re-establishment into the canopy of deciduous forests of the region. We examined the potential for ash re-establishment in areas of heavy mortality by measuring the status and change of ash regeneration at 45 sites across southeastern Lower Michigan in 2007 and 2009. Ash regeneration was found to be abundant in all forest types, particularly in the smallest height classes, though it was more abundant in ash species of upland forests compared to those of lowland forests. New seedlings 1–2 years old were less common than other regeneration size classes, and declined substantially between 2007 and 2009, suggesting a depletion of the ash seed bank in these forests. Regeneration density was not explained well by the presence of overstory ash prior to EAB introduction, suggesting that competitive interaction with other tree species in higher canopy strata is an important driver of ash regeneration density. Regeneration is sufficient to replenish overstory ash to pre-EAB levels in upland forests, though ecological changes caused by overstory ash mortality in lowland areas may affect local hydrology in a way that reduces opportunities for tree regeneration. Despite abundant ash regeneration, it remains unclear whether ash will recover to the overstory of forests in southeastern Michigan because of uncertainties in the future dynamics of EAB in the region.

Residents' Perceptions of Environmental and Security Issues at the 2012 London Olympic Games

Staging a mega sport event such as the Olympic Games has been traditionally viewed as a ‘golden’ opportunity for urban regeneration and economic development. Research into residents' perceptions of environmental impacts and security risks at Olympic Games is limited. This paper discusses residents' perceptions of environmental and security issues associated with the London 2012 Olympic Games. The study used a purposive sample of local residents (n = 100) of which 50% were in the age range of 18–34 years (Group A) and 50% were 35–55 years or over (Group B). Forty-two per cent of Group A and 28% of Group B lived in London. Data were collected through self-administered questionnaires. Findings showed that the majority of respondents in both groups overwhelmingly supported the 2012 Games and were filled with a sense of national pride and excitement for London being the host city. However, findings also demonstrated differences between the age groups in their perceptions of the environmental impacts of the 2012 Games. Group B expressed consistently more negative attitudes compared with Group A with regards to pollution, traffic congestion and parking availability. Both groups were equally concerned about the inadequacies of the transport system. Group B respondents also perceived increased security risks during the Games that could negatively affect attendance at the Games. Both groups showed a lack of confidence that security would be ensured at the Games. These findings contradict planned environmental and security initiatives that are currently underway and indicate that 2012 stakeholders need to improve communication and public consultation to raise public awareness and instil confidence.