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Teaching ethics in organ transplantation and tissue donation - cases and movies

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ISBN: 9783941875401 Year: Pages: 88 Language: English
Publisher: Universitätsverlag Göttingen
Subject: Medicine (General) --- Philosophy
Added to DOAB on : 2012-04-11 21:20:13
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Organ transplantation is a thrilling new option for modern surgery giving hope for chronically ill patients, and, at the same time, stirring controversial ethical questions on human identity and the meaning of the human body. Being a global and transnational endeavor, organ transplantation raises universal ethical concerns and, yet, has to be adapted to culturally mediated believes. In this book, 30 case studies collected from all over the world illustrate the range of global and local, ethical, social, and cultural problems associated with this new form of treatment. Together with a list of relevant movies, the collection provides a unique resource for ethics education in medicine, health care, philosophy, and religious studies. The authors have completed the teaching material by a systematic introduction into the field of transplantation ethics.

Searching for Immune Tolerance Manipulating New Molecules and Exploiting New Concepts on Lymphocyte Biology

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199518 Year: Pages: 143 DOI: 10.3389/978-2-88919-951-8 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2016-01-19 14:05:46
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The break on immune tolerance is a common point between autoimmune diseases and the uncontrolled effector immune responses against allo-antigens in transplantation. Among the past years, several approaches to restore a suppressive immune state have included the targeting of co-stimulatory/inhibitory molecules on immune cells, the promotion or blockade of pivotal cytokines, and the extensive study on how to isolate and expand suppressive cells with the purpose to re-infuse them in patients. To date, the availability of new technologies has permitted to learn, in a more detailed way, the immune mechanisms carried out by suppressive lymphocytes, together with the identification of new potential candidates to target in our quest for immune tolerance. For example, the attractive concepts of lymphocyte plasticity and function stability, supported by the finding of new transcription factors, have opened a new window in the understanding of T cell differentiation, effector cell commitment and immune regulatory function. On the other hand, the discovery of new members of the Ig superfamily ligand, VISTA; the intriguing role of modulatory molecules like Retinoic Acid, Neuropilin-1, Fc gamma receptors, or cytokines such as IL-33, among others, are revealing new possibilities in the development of new strategies to conquer our obsession: immune tolerance. Here, we gather the latest information regarding new targets and cellular processes, including an update on current cellular therapies and the exciting coming approaches to cure autoimmunity and permit transplant acceptance.

Metabolism and Immune Tolerance

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889457250 Year: Pages: 116 DOI: 10.3389/978-2-88945-725-0 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2019-01-23 14:53:43
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Historically the study of the immune system and metabolism have been two very separate fields. In recent years, a growing literature has emerged illustrating how the multiple processes of cellular metabolism are intricately linked to several aspects of immune function and development. This Research Topic covers recent progress in the field now known as “Immunometabolism” and the role of metabolism in immune tolerance. Immune tolerance is operationally defined as a state where a host’s immune system is balanced such that although self-reactive lymphocytes are present, they are kept in check by immune regulation. Perturbations to this homeostasis may result in self-reactive lymphocytes gaining the upper hand and mediating auto-immune disease. Maintenance of immune tolerance involves a large cast of different cell types including effector T cells, regulatory T cells, B cells, stromal cells, dendritic cells and macrophages.Intracellular pathways and individual enzymes of metabolism have been shown to be harnessed by cells of both the adaptive and innate immune system to allow particular immune functions to be achieved. Examples include metabolic enzymes serving ‘moonlighting’ functions in mRNA translation, gene splicing, and kinase activation. Other examples include the requirement for de novo fatty acid synthesis for differentiation into Th17 effectors and CD8 memory T cells or products of the TCA cycle promoting pro-inflammatory cytokine production. Likewise, the availability of extracellular metabolic substrates has a large impact on the maintenance of local immune tolerance. For example, there are different requirements for glucose, glutamine and fatty acids for effector versus regulatory T cell development. Also tolerogenic dendritic cells mediate lowering of extracellular essential amino acids by their enhanced catabolism, promoting the induction of regulatory T cells. The purpose of this Research Topic is to provide an update on the current understanding of the multiple roles for metabolism in regulating the immune system.

Fetal Therapies and Maternal-Fetal Tolerance

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199839 Year: Pages: 84 DOI: 10.3389/978-2-88919-983-9 Language: English
Publisher: Frontiers Media SA
Subject: Therapeutics --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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The ability to diagnose and treat genetic diseases before birth represents one of the foremost breakthroughs of modern medicine. While fetal surgery has advanced in the last several decades, the prospect of applying developments in stem cell biology and gene therapy to the fetal environment remains an open frontier. This issue represents the work of international experts in the field of fetal therapy, who came together at the first meeting of the International Fetal Transplantation and Immunology Society in 2014. This meeting was convened in an effort to provide a consensus for future applications of in utero transplantation and gene therapy, as well as form an international community of colleagues to nurture this field.

AML in the Molecular Age: From Biology to Clinical Management

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ISBN: 9783038972808 9783038972815 Year: Pages: 208 DOI: 10.3390/books978-3-03897-281-5 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Therapeutics
Added to DOAB on : 2018-10-12 12:12:38
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We appreciate your willingness to contribute an article to the upcoming Special Issue of the Journal of Clinical Medicine, which will focus on “AML in the Molecular Age: From Biology to Clinical Management”. In this Special Issue, we aim to discuss important scientific and clinical ongoing activities in AML. Scientific subjects will include articles concerning the molecular abnormalities, epigenetic mechanisms of disease/therapy as well as the role of the immune system in AML. Very interesting and uncommon subjects will include discussions of extramedullary disease and evaluations of the central nervous system by various imaging techniques. Experts will describe the role of hypomethylating agents in the management of AML and currently emerging and promising investigational therapies. Specifics of treament of pediatric and younger patients with AML. Clinical success relies greatly on supportive therapy, and we will discuss supportive therapy, including infection prophylaxis. Allogeneic hematopoietic stem cell transplantation remains the most effective measure for curing aggressive AML, and a variety of topics will be considered: donor selection, age of recipient, which has been increasing seemingly without limit; therefore, recipient/donor assessments are more important than ever in the aging population. Alternative donor use (e.g., cord blood and haploidentical individuals) has been increasing dramatically; when and who should be considered, what is being investigated? With significant changes occurring with respect to both donors and recipients, the pros and cons of using of anti-thymocyte globulin use in conditioning regimens will be also described.

Stem cells and progenitor cells in ischemic stroke - fashion or future?

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197248 Year: Pages: 156 DOI: 10.3389/978-2-88919-724-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
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Stroke remains one of the most devastating diseases in industrialized countries. Recanalization of the occluded arterial vessel using thrombolysis is the only causal therapy available. However, thrombolysis is limited due to severe side effects and a limited time window. As such, only a minority of patients receives this kind of therapy, showing a need for new and innovative treatment strategies. Although neuroprotective drugs have been shown to be beneficial in a variety of experimental stroke models, they ultimately failed in clinical trials. Consequently, recent scientific focus has been put on modulation of post-ischemic neuroregeneration, either via stimulation of endogenous neurogenesis or via application of exogenous stem cells or progenitor cells. Neurogenesis persists within the adult brain of both rodents and primates. As such, neural progenitor cells (NPCs) are found within distinct niches like the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone of the dentate gyrus. Cerebral ischemia stimulates these astrocyte-like progenitor cells, upon which NPCs proliferate and migrate towards the site of lesion. There, NPCs partly differentiate into mature neurons, without significantly being integrated into the residing neural network. Rather, the majority of new-born cells dies within the first weeks post-stroke, leaving post-ischemic neurogenesis a phenomenon of unknown biological significance. Since NPCs do not replace lost brain tissue, beneficial effects observed in some studies after either stimulated or protected neurogenesis are generally contributed to indirect effects of these new-born cells. The precise identification of appropriated cellular mediators, however, is still elusive. How do these mediators work? Are they soluble factors or maybe even vesicular structures emanating from NPCs? What are the cues that guide NPCs towards the ischemic lesion site? How can post-ischemic neurogenesis be stimulated? How can the poor survival of NPCs be increased? In order to support post-ischemic neurogenesis, a variety of research groups have focused on application of exogenous stem/progenitor cells from various tissue sources. Among these, cultivated NPCs from the SVZ and mesenchymal stem cells (MSCs) from the bone marrow are frequently administered after induction of stroke. Although neuroprotection after delivery of stem/progenitor cells has been shown in various experimental stroke models, transplanted cells are usually not integrated in the neural network. Again, the vast amount of grafted cells dies or does not reach its target despite profound neuroprotection, also suggesting indirect paracrine effects as the cause of neuroprotection. Yet, the factors being responsible for these observations are under debate and still have to be addressed. Is there any “optimal” cell type for transplantation? How can the resistance of grafted cells against a non-favorable extracellular milieu be increased? What are the molecules that are vital for interaction between grafted cells and endogenous NPCs? The present research topic seeks to answer - at least in part - some of the aforementioned questions. Although the research topic predominantly focuses on experimental studies (and reviews alike), a current outlook towards clinical relevance is given as well.

Allorecognition by Leukocytes of the Adaptive Immune System

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453863 Year: Pages: 107 DOI: 10.3389/978-2-88945-386-3 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-11-16 17:17:57
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The term allorecognition refers to the series of mechanisms used by an individual’s immune system to distinguish its own cells and tissues from those of another individual belonging to the same species. During evolution, different cells and molecules of both innate and adaptive immune systems have been selected to recognize and respond to antigens expressed by allogeneic cells, but not autologous cells (alloantigens). This research topic focuses on allorecognition by lymphocytes of the adaptive immune system and its involvement in rejection or tolerance of allogeneic transplants. T and B cells recognizing alloantigens via specific receptors become activated and undergo proliferation and differentiation into different types of effector and memory cells. Allorecognition by lymphocytes occurs regularly during pregnancy upon trafficking of both maternal and fetal cells. In this setting, allorecognition triggers an alloresponse that is protective towards the fetus thus preventing abortion. Protective alloimmunity is mediated through cooperation between different lymphocytes and antigen presenting cells (APCs), as well as regulatory mediators and receptors. Likewise, certain transplants placed in organs and tissues called immune-privileged sites such as the eye, the central nervous system and the testis elicit protective rather than destructive adaptive immune responses. Therefore, under certain circumstances, allorecognition by regulatory lymphocytes (Tregs and Bregs) can lead to tolerance of alloantigens. In contrast, allorecognition by T cells in non-immune privileged sites and under inflammatory conditions leads to a destructive immune response. Indeed, after transplantation of most allogeneic organs and tissues, activation of pro-inflammatory T cells (TH1 and TH17), which recognize donor MHC proteins (direct pathway) or peptides derived from donor MHC and minor antigens (indirect pathway), leads to graft rejection. This inflammatory response leads to the differentiation of allospecific cytotoxic T cells as well as production of donor specific antibodies by B cells, both of which contribute to the destruction of the transplant. In this Research Topic, we describe the different pathways of allorecognition by T cells involved in allograft rejection, as well as the role of different antigen presenting cells and graft-derived microvesicles (exosomes) involved in this process. Another aspect of this Research Topic addresses the essential role of alloreactive memory T cells in allograft rejection and resistance to transplant tolerance induction in laboratory rodents, as well as non-human primates and patients. Indeed, it has become evident that laboratory mice display very few memory alloreactive T cells pre-transplantation, essentially due to the fact that they are raised in pathogen-free facilities. In contrast, primates display high frequencies of alloreactive memory T cells, either generated through prior exposure to allogeneic MHC molecules or via cross-reactivity with microbial antigens. We and others have provided ample evidence showing that this feature accounts for differences in terms of tolerance susceptibility between laboratory rodents and patients. This implies that further investigation of tolerance protocols in laboratory mice should be performed using “dirty mice” i.e., mice raised in non-sterile conditions. In summary, this Research Topic addresses key aspects of allorecognition by lymphocytes and alloantigen presentation by dendritic cells, and specifically how these processes shape our immune system and govern the rejection or tolerance of allogeneic tissues and organs.

Developing Stem Cell-Based Therapies For Neural Repair

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194025 Year: Pages: 114 DOI: 10.3389/978-2-88919-402-5 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:06
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Current pharmacotherapies and surgical intervention provide limited benefit in the treatment of neural injuries or halting disease progression and has resulted in significant hope for the successes of stem cell research. The properties of stem cells render them appropriate for cell replacement therapy, endogenous repair, disease modeling as well as high-throughput drug screening and development. Such applications will aide in increasing our knowledge and developing treatments for neurodegenerative disorders such as Parkinson’s disease and Huntington’s diseases as well as neural traumas including ischemic brain damage and traumatic brain injury. This Frontiers Research topic encouraged contributions from the general field of stem cell biology, with a particular emphasis on utilizing these cells to develop new therapies for neural repair. Related articles deal with issues such as: breakthroughs in stem cell proliferation/differentiation methodologies, using pluripotent and neural stem cells for transplantation and endogenous repair, the use of patient derived stem cells for disease modeling, using stem cells for drug discovery as well as the ethical issues related to the use of stem cells.

Natural Killer Cells in Human Diseases: Friends or Foes?

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454044 Year: Pages: 122 DOI: 10.3389/978-2-88945-404-4 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-11-16 17:17:57
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NK cells are lymphocytes of the innate immune system that share some features with adaptive immune cells like T cells. They are well known for their importance to control viral infections and tumor development, but also intracellular bacterial and parasitic infections. A balance between negative and positive signals transmitted via germ line-encoded inhibitory and activating receptors controls the function of NK cells. Activated NK cells respond by killing the infected or tumor cells without prior sensitization, and by producing cytokines and chemokines. It has been shown that NK cells cross-talk with other immune cells, such as dendritic cells and macrophages, can shape T cell and B cell immune responses through direct interactions as well as by virtue of their cytokine/chemokine production. NK cells can also regulate immune responses by killing other immune cells, including activated T cells, or by producing anti-inflammatory cytokines upon excessive inflammation. However, NK cells are not friends in all situations. Indeed, it has been shown in LCMV-infected murine models that, depending on the viral inoculation load, NK cells may either help fight infection or can promote chronic infection. Moreover in cancer models, it has been shown that NK cells can kill anti-tumoral T cells. Recent studies of NK cells in patients with cancer support the notion of detrimental roles of NK cells. Furthermore, studies implicate NK cells in contributing to both graft rejection and tolerance to an allograft. In some autoimmune diseases, like rheumatoid arthritis, NK cells may promote disease pathogenesis. The scope of this Research Topic is to present and discuss knowledge on the role of NK cells in various diseases settings: viral infections as well as other infections, cancer, transplantation, and autoimmunity. The aim is to discuss how NK cells respond during disease and specifically when, why and how NK cells can be harmful and if they exert different functions (production of specific cytokines, inhibition of other immune cells through other mechanisms beside cytotoxicity) in these situations. Which are the NK cell subsets that play beneficial or deleterious roles in these diseases? Are there different phenotypes associated with protective NK cells (e.g. antiviral, antitumoral) and NK cells involved in disease pathogenesis? How are these diverse NK cells activated and do they function primarily through direct cytotoxicity, ADCC or cytokine and chemokine production? What are the signals or interactions that can change and shape the NK cell response shifting them from protective to harmful? We thank the authors that submitted reviews and original research manuscripts that help to better understand these questions, with the aim that this will help the scientific community to determine what could be the main future research directions to better understand the role of NK cells in disease protection or development.

Tailoring NK Cell Receptor-Ligand Interactions: An Art in Evolution

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454648 Year: Pages: 407 DOI: 10.3389/978-2-88945-464-8 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-11-16 17:17:57
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Recognition and killing of aberrant, infected or tumor targets by Natural Killer (NK) cells is mediated by positive signals transduced by activating receptors upon engagement of ligands on target surface. These stimulatory pathways are counterbalanced by inhibitory receptors that raise NK cell activation threshold through negative antagonist signals. While regulatory effects are necessary for physiologic control of autoimmune aggression, they may restrain the ability of NK cells to activate against disease. Overcoming this barrier to immune surveillance, multiple approaches to enhance NK-mediated responses are being investigated since two decades. Propelled by considerable advances in the understanding of NK cell biology, these studies are critical for effective translation of NK-based immunotherapy principles into the clinic. In humans, dominant inhibitory signals are transduced by Killer Immunoglobulin Like Receptors (KIR) recognizing cognate HLA class I on target cells. Conversely, KIR recognition of “missing self-HLA” - due to HLA loss or HLA/ KIR mismatch - triggers NK-mediated tumor rejection. Initially observed in murine transplant models, these antitumor effects were later found to have important implications for the clinical outcome of haplotype-mismatched stemcell transplantation. Here, donor NK subsets protect against acute myeloid leukemia (AML) relapse through missing self recognition of donor HLA-C allele groups (C1 or C2) and/or Bw4 epitope. These studies were subsequently extended by trials investigating the antileukemia effects of adoptively transferred haplotype-mismatched NK cells in non-transplant settings. Other mechanisms have been found to induce clinically relevant NK cell alloreactivity in transplantation, e.g., post-reconstitution functional reversal of anergic NK cells. More recently, activating KIR came into the spotlight for their potential ability to directly activate donor NK cells through in vivo recognition of HLA or other ligands. Novel therapeutic monoclonal antibodies (mAb) may optimize NK-mediated effects. Examples include obinutuzumab (GA101), a glyco-engineered anti-CD20 mAb with increased affinity for the FcγRIIIA receptor, enhancing antibody-dependent cellular cytotoxicity; lirilumab (IPH2102), a first-in-class NK-specific checkpoint inhibitor, blocking the interaction between the major KIR and cognate HLA-C antigens; and elotuzumab (HuLuc63), a humanized monoclonal antibody specific for SLAMF7, whose anti-myeloma therapeutic effects are partly due to direct activation of SLAMF7-expressing NK cells. In addition to conventional antibodies, NK cell-targeted bispecific (BiKEs) and trispecific (TriKEs) killer engagers have also been developed. These proteins elicit potent effector functions by binding target ligands (e.g., CD19, CD22, CD30, CD133, HLA class II, EGFR) on one arm and NK receptors on the other. An additional innovative approach to direct NK cell activity is genetic reprogramming with chimeric antigen receptors (CAR). To date, primary NK cells and the NK92 cell line have been engineered with CAR specific for antigens expressed on multiple tumors. Encouraging preclinical results warrant further development of this approach. This Research Topic welcomes contributions addressing mechanisms of NK-mediated activation in response to disease as well as past and contemporary strategies to enhance NK mediated reactivity through control of the interactions between NK receptors and their ligands.

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