Naturally-occurring and cultured bacteriophages in human therapy.

OBJECTIVE: The aim of the study was to show the importance of developing techniques that could exploit the potential of bacteriophages as therapeutics or food supplements. MATERIALS AND METHODS: PubMed database was searched using the following combination of keywords: (bacteriophage) AND (human therapy); (natural bacteriophage) AND (application). RESULTS: The increasing antibiotic resistance of many bacterial strains is making standard antibiotic treatments less effective. Phage therapy provides a non-antibiotic alternative with greater specificity and without harmful effects on the human microbiota. Phages target their specific bacteria, replicate, and then, destroy the host pathogen. Bacteriophages may be administered by several routes, including topical, oral and intravenous. They not only destroy the host pathogen but, in some cases, increase the sensitivity of host bacteria to antibiotics. Various studies have shown that combining phage therapy and antibiotic treatment can be effective against bacterial infections. Clinical trials of phage therapy have shown promising results for various human diseases and conditions. With advances in genetic engineering and molecular techniques, bacteriophages will be able to target a wide range of bacteria. CONCLUSIONS: In the future, phage therapy promises to become an effective therapeutic option for bacterial infections. Since many potentially beneficial bacteriophages can be found in food, supplements containing bacteriophages could be designed to remodel gut microbiota and eliminate pathogenic bacteria. Remodeling of gut microbiota could correct gut dysbiosis. The order of phages known to have these promising activities is Caudovirales, especially the families Siphoviridae and Myoviridae.

A Way Forward for Culturing Plasmodium vivax.

Trager and Jensen established a method for culturing Plasmodium falciparum, a breakthrough for malaria research worldwide. Since then, multiple attempts to establish Plasmodium vivax in continuous culture have failed. Unlike P. falciparum, which can invade all aged erythrocytes, P. vivax is restricted to reticulocytes. Thus, a constant supply of reticulocytes is considered critical for continuous P. vivax growth in vitro. A critical question remains why P. vivax selectively invades reticulocytes? What do reticulocytes offer to P. vivax that is not present in mature erythrocytes? One possibility is protection from oxidative stress by glucose-6-phosphate dehydrogenase (G6PD). Here, we also suggest supplements to the media and procedures that may reduce oxidative stress and, as a result, establish a system for the continuous culture of P. vivax.

Aquatic Parasite Cultures and Their Applications.

In this era of unprecedented growth in aquaculture and trade, aquatic parasite cultures are essential to better understand emerging diseases and their implications for human and animal health. Yet culturing parasites presents multiple challenges, arising from their complex, often multihost life cycles, multiple developmental stages, variable generation times and reproductive modes. Furthermore, the essential environmental requirements of most parasites remain enigmatic. Despite these inherent difficulties, in vivo and in vitro cultures are being developed for a small but growing number of aquatic pathogens. Expanding this resource will facilitate diagnostic capabilities and treatment trials, thus supporting the growth of sustainable aquatic commodities and communities.

Monogenean Parasite Cultures: Current Techniques and Recent Advances.

Global expansion in fish production and trade of aquatic ornamental species requires advances in aquatic animal health management. Aquatic parasite cultures permit diverse research opportunities to understand parasite-host dynamics and are essential to validate the efficacy of treatments that could reduce infections in captive populations. Monogeneans are important pathogenic parasites of captured captive fishes and exhibit a single-host life cycle, which makes them amenable to in vivo culture. Continuous cultures of oviparous monogenean parasites provide a valuable resource of eggs, oncomiracidia (larvae) and adult parasites for use in varied ecological and applied scientific research. For example, the parasite-host dynamics of Entobdella soleae (van Beneden and Hesse, 1864) and its fish host, Solea solea (Linnaeus, 1758), is one of the most well-documented of all monogeneans following meticulous, dedicated study. Polystoma spp. cultures provide an intriguing model for examining evolution in monogeneans because they exhibit two alternative phenotypes depending on the age of infection of amphibians. Furthermore, assessments of the ecological, pathological and immunological effects of fish parasites in aquaculture have been achieved through cultures of Gyrodactylus von Nordmann, 1832 spp., Benedenia seriolae (Yamaguti, 1934), Neobenedenia Yamaguti, 1963 spp. and Zeuxapta seriolae (Meserve, 1938). This review critically examines methods to establish and maintain in vivo monogenean monocultures on finfish, elasmobranchs and amphibians. Four separate approaches to establish cultures are scrutinised including the collection of live infected hosts, cohabiting recipient hosts with infected stock, cohabiting hosts with parasite eggs or oncomiracidia (larvae) and direct transfer of live adult parasites onto new fish hosts. Specific parasite species' biology and behaviour permits predictive collection of parasite life stages to effectively maintain a continuous culture, while environmental parameters can be altered to manipulate parasite generation time. Parasite virulence and biosecurity are vital components of a well-managed culture to ensure appropriate animal welfare and uncontaminated surrounding environments. Contemporary approaches and techniques are reviewed to ensure optimised monogenean cultures, which ultimately can be used to further our understanding of aquatic parasitology and identify mechanisms to limit infestations in public aquaria, ornamental trade and intensive aquaculture.

From culturomics to taxonomogenomics: A need to change the taxonomy of prokaryotes in clinical microbiology.

By diversifying culture conditions, in a strategy named culturomics, we were able in a short time to grow 124 new bacterial species from human stools, including 39 strict anaerobes. To describe these microorganisms, we use genome sequencing and MALDI-TOF mass spectrometry. Both tools have been major breakthroughs in clinical microbiology over the past decade, have previously been used for taxonomic purposes, and have the advantage over chemotaxonomic methods and DNA-DNA hybridization, to exhibit an excellent intra- and inter-laboratory reproducibility. We developed a polyphasic taxonomic strategy including MALDI-TOF MS and genomic analyses to describe new bacterial species associated with human beings. This strategy, that we have named taxono-genomics, was used to propose the description of 48 new species, the names of 13 of which have officially been validated. In this manuscript, we briefly reviewed the pros and cons of the currently validated taxonomic tools and propose that genomic sequencing and MALDI-TOF mass spectrometry may be incorporated in the taxonomic classification of prokaryotes.

Ex vivo expansion of cord blood.

A marked increase in the utilization of umbilical cord blood (UCB) transplantation has been observed in recent years; however, the use of UCB as a hematopoietic stem cell (HSC) source is limited primarily by the number of progenitor cells contained in the graft. Graft failure, delayed engraftment and profound delay in immune reconstitution lead to significant morbidity and mortality in adults. The lack of cells available for post transplant therapies, such as donor lymphocyte infusions, has also been considered to be a disadvantage of UCB. To improve outcomes and extend applicability of UCB transplantation, one potential solution is ex vivo expansion of UCB. Investigators have used several methods, including liquid suspension culture with various cytokines and expansion factors, co-culture with stromal elements and continuous perfusion systems. Techniques combining ex vivo expanded and unmanipulated UCB are being explored to optimize the initial engraftment kinetics as well as the long-term durability. The optimal expansion conditions are still not known; however, recent studies suggest that expanded UCB is safe. It is hoped that by ex vivo expansion of UCB, a resulting decrease in the morbidity and mortality of UCB transplantation will be observed, and that the availability of additional cells may allow adoptive immunotherapy or gene transfer therapies in the UCB setting.

[Therapeutic applications and promises of cellular and tissue engineering. What strategic choice for the Etablissement Français du Sang?]. / Domaines d'application et enjeux de l'ingénierie et de la thérapie cellulaires et tissulaires. Quel choix stratégique pour l'EFS ?

A new medical field, known as regeneration medicine, is developing and attracting more and more researchers and practitioners. Whereas hematopoietic cell-based therapies have already proven their efficacy in numerous--malignant or not--diseases, non-hematopoietic cell-based therapies have not. They can be useful to dozens, if not hundreds, of patients with various disorders, such as cardiopathy, diabetes, some types of cancer, osteoarticular and neurodegenerative disorders. In these fields, numerous clinical applications are possible for mesenchymal stem cells. Cell and tissue (corneas, bone, skin) therapy products require the definition of pharmaceutical standards with new European requirements in terms of quality and safety. The legitimacy of the Etablissement Français du Sang (EFS) in cell and tissue engineering activities is established, it is recognized by most specialists and by regulatory authorities and has been asserted by the orientations of its "contrat d'objectifs et de moyens". An independent committee has been set up by the EFS President to define an EFS-specific strategy. This committee made up of qualified specialists was required to draw up a rational organization plan for these activities, in order for EFS to be in a position to produce cells and tissues according to pharmaceutical standards. The committee proposals are based on economic data and an inventory of existing cell and tissue engineering activities. Public/private partnerships are required and efforts must focus towards the industrial valorization of EFS expertise in R&D activities and staff know-how. Implementing such a new organization requires national management and the cooperation of institutional actors (university hospitals, cancer treatment centers, universities). For the success of this approach, EFS personnel must be convinced of its legitimacy and new skills must be encouraged. With its numerous assets, EFS can be ambitious and assert itself as a major actor in cell and tissue engineering in Europe.

Hematopoietic stem cells: clinical requirements and developments in ex-vivo culture.

Ex vivo expansion of hematopoietic stem cells is a promising technology for many potential applications from marrow reconstitution to gene therapy. Considerable progress has been made during the past ten years in understanding the biology of hematopoietic stem cells and its ex vivo expansion; despite this, the cultured cell is still between pre-clinical and phase I clinical trials. This review summarizes recent progress in the ex vivo expansion of hematopoietic stem cells and its requirements for clinical applications. The second section covers hematopoiesis and the bone marrow microenvironment. The third and fourth sections deal with therapeutic applications of stem cells and transplantation requirements, respectively. Biological alteration of expanded stem cells, molecular control of hematopoiesis, characterization of cells, and bioreactors for culture of stem cells and its operational parameters are the subjects of the fifth section. The next section covers pre-clinical and clinical studies on expanded stem cells. Ex vivo expansion of stem cells in three-dimensional culture system is the subject matter for the last section.

Seasonal fantasies in scaffolds.

When tissue-engineering (TE) products started to emerge a few years ago, it seemed that the natural choice for the degradable scaffolds would be the same synthetic aliphatic polyesters that are used for absorbable medical devices. However, it is now becoming clearer that different solutions are required for the construction of these important constituents of TE products.

Organ printing: computer-aided jet-based 3D tissue engineering.

Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an engineering approach with the developmental biology concept of embryonic tissue fluidity enables the creation of a new rapid prototyping 3D organ printing technology, which will dramatically accelerate and optimize tissue and organ assembly.

[Industrialization of medicinal plant tissue culture].

Compared with other countries, the industrialization of medicinal plant tissue culture is more important for our country because China is consuming and exporting the most amounts of herb materials in the world. Each year, many papers and patents are published on cell cultures of popular medicinal plants, such as Taxus sp., Catharanthus roseus, and Panax ginseng, and, meanwhile, the research on organ cultures of medicinal plants is increasing very quickly, which is deepening the study of medicinal plant tissue culture. During the past 30 years, Chinese scientists have cultured many medicinal plant cells, organs and hairy roots. In addition, the large-scale cultures have been tested on medicinal plants, such as Catharanthus roseus, Panax notoginseng, Anisodus acutangulus, Lithospermum erythrorhizon, and Taxus chinensis. However, the bioreactor size is not big enough for the commercial cultivation and we have not mastered the culture technique on a large scale. We should clearly understand the importance and great potential benefit of medicinal plant tissue culture and develop the tissue culture techniques for the modernization of TCM. To develop the technique that we have the property right, the pioneering spirit is needed in our research, and, meanwhile, it should be pointed out emphatically the collaboration is indispensable among scientists from different research fields.

Treatment of chronic wounds: state of the art and future concepts.

The morbidity and mortality from chronic wounds of varying etiology present a significant health care problem. Multiple local disturbances and systemic disease can impair wound healing. Recently, experiments with tissue cultures and animal models have revolutionized the understanding of wound healing and the pathophysiological processes involved. In cooperation with clinicians and industrial partners novel therapeutic concepts including the topical application of growth factors and cell therapies have been developed. Cytokines that have been tested in clinical studies include epidermal growth factor, platelet-derived growth factor and fibroblast growth factor. These studies showed that an important aspect of the growth factor wound healing paradigm is the effective delivery of these polypeptides to the wound site. Current drug delivery strategies suffer from the inherent loss of drug activity due to the combined effects of physical inhibition and biological degradation. A molecular genetic approach in which genetically modified cells synthesize and deliver the desired growth factor in a time-regulated manner is a powerful means to overcome the limitations associated with the topical application of recombinant growth factor proteins.

Vaccine could not have been prepared in Stanleyville.

In Stanleyville, at the time of vaccination campaigns, tissue cultures were primitive, experimental and used solely for diagnostic purposes. Production of vaccine was impossible to carry out. A few chimpanzee kidneys were minced and sent to Philadelphia as part of the hepatitis experiments of Dr Deinhardt. Vaccine was never handled in my laboratory and contamination with chimpanzee cells was not possible.

Tissue engineering: current state and prospects.

Organ shortage and suboptimal prosthetic or biological materials for repair or replacement of diseased or destroyed human organs and tissues are the main motivation for increasing research in the emerging field of tissue engineering. No organ or tissue is excluded from this multidisciplinary research field, which aims to provide vital tissues with the abilities to function, grow, repair, and remodel. There are several approaches to tissue engineering, including the use of cells, scaffolds, and the combination of the two. The most common approach is biodegradable or resorbable scaffolds configured to the shape of the new tissue (e.g. a heart valve). This scaffold is seeded with cells, potentially derived from either biopsies or stem cells. The seeded cells proliferate, organize, and produce cellular and extracellular matrix. During this matrix formation, the starter matrix is degraded, resorbed, or metabolized. First clinical trials using skin or cartilage substitutes are currently under way. Both the current state of the field and future prospects are discussed.

ASTM lights the way for tissue engineered medical products standards: jump start for combination medical products that restore biological function of human tissues.

Everybody hopes for better health and restoration of impaired bodily function, and now that hope is illuminated by the promise of powerful biological tools that make human cells grow and replace human tissue. ASTM Committee F04 on Medical and Surgical Materials and Devices is taking the lead by defining some of those tools as standards that can be used for the development, production, testing, and regulatory approval of medical products.