Skin Transplantation
Transplantation, Homologous
Graft Rejection
Graft Survival
Liver Transplantation
Mice, Inbred BALB C
Mice, Inbred C57BL
Bone Marrow Transplantation
Skin
Hematopoietic Stem Cell Transplantation
Transplantation, Autologous
Lung Transplantation
Stem Cell Transplantation
Transplantation Conditioning
Organ Transplantation
Islets of Langerhans Transplantation
Tissue Donors
Transplantation
Transplantation Immunology
Cell Transplantation
Skin Diseases
Transplantation Chimera
Skin Aging
Immunosuppressive Agents
Graft vs Host Disease
Transplantation, Isogeneic
Treatment Outcome
Transplantation, Heterotopic
Cord Blood Stem Cell Transplantation
Thymic selection by a single MHC/peptide ligand: autoreactive T cells are low-affinity cells. (1/1550)
In H2-M- mice, the presence of a single peptide, CLIP, bound to MHC class II molecules generates a diverse repertoire of CD4+ cells. In these mice, typical self-peptides are not bound to class II molecules, with the result that a very high proportion of H2-M- CD4+ cells are responsive to the various peptides displayed on normal MHC-compatible APC. We show here, however, that such "self" reactivity is controlled by low-affinity CD4+ cells. These cells give spectacularly high proliferative responses but are virtually unreactive in certain other assays, e.g., skin graft rejection; responses to MHC alloantigens, by contrast, are intense in all assays. Possible explanations for why thymic selection directed to a single peptide curtails self specificity without affecting alloreactivity are discussed. (+info)Evaluation of fibroblast-mediated gene therapy in a feline model of mucopolysaccharidosis type VI. (2/1550)
Fibroblast-mediated ex vivo gene therapy was evaluated in the N-acetylgalactosamine 4-sulfatase (4S) deficient mucopolysaccharidosis type VI (MPS VI) cat. Skin biopsies were obtained at birth from severely affected MPS VI kittens and used to initiate fibroblast outgrowths for retroviral transduction with the 4S cDNA. 4S gene expression in transduced cells was under the transcriptional control of the MoMLV long terminal repeat promoter or the cytomegalovirus (CMV) immediate-early promoter. Characterisation of gene-transduced fibroblasts demonstrated the cells to be over-expressing 4S activity. Twenty-four to forty million autologous, gene-corrected fibroblasts were implanted under the renal capsule of three MPS VI kittens at 8-16 weeks of age. Transient, low levels of 4S activity were detected in peripheral blood leukocytes shortly after implantation but were not detectable within 3-8 weeks' post-implantation. Long-term biochemical and clinical evaluation of these cats demonstrated identical disease progression to that previously described in untreated, clinically severe MPS VI cats. (+info)Mid-term results of endoscopic perforator vein interruption for chronic venous insufficiency: lessons learned from the North American subfascial endoscopic perforator surgery registry. The North American Study Group. (3/1550)
PURPOSE: The safety, feasibility, and early efficacy of subfascial endoscopic perforator surgery (SEPS) for the treatment of chronic venous insufficiency were established in a preliminary report. The long-term clinical outcome and the late complications after SEPS are as yet undetermined. METHODS: The North American Subfascial Endoscopic Perforator Surgery registry collected information on 148 SEPS procedures that were performed in 17 centers in the United States and Canada between August 1, 1993, and February 15, 1996. The data analysis in this study focused on mid-term outcome in 146 patients. RESULTS: One hundred forty-six patients (79 men and 67 women; mean age, 56 years; range, 27 to 87 years) underwent SEPS. One hundred and one patients (69%) had active ulcers (class 6), and 21 (14%) had healed ulcers (class 5). One hundred and three patients (71%) underwent concomitant venous procedures (stripping, 70; high ligation, 17; varicosity avulsion alone, 16). There were no deaths or pulmonary embolisms. One deep venous thrombosis occurred at 2 months. The follow-up periods averaged 24 months (range, 1 to 53 months). Cumulative ulcer healing at 1 year was 88% (median time to healing, 54 days). Concomitant ablation of superficial reflux and lack of deep venous obstruction predicted ulcer healing (P <.05). Clinical score improved from 8.93 to 3.98 at the last follow-up (P <. 0001). Cumulative ulcer recurrence at 1 year was 16% and at 2 years was 28% (standard error, < 10%). Post-thrombotic limbs had a higher 2-year cumulative recurrence rate (46%) than did those limbs with primary valvular incompetence (20%; P <.05). Twenty-eight of the 122 patients (23%) who had class 5 or class 6 ulcers before surgery had an active ulcer at the last follow-up examination. CONCLUSIONS: The interruption of perforators with ablation of superficial reflux is effective in decreasing the symptoms of chronic venous insufficiency and rapidly healing ulcers. Recurrence or new ulcer development, however, is still significant, particularly in post-thrombotic limbs. The reevaluation of the indications for SEPS is warranted because operations in patients without previous deep vein thrombosis are successful but operations in those patients with deep vein thrombosis are less successful. Operations on patients with deep vein occlusion have poor outcomes. (+info)The 60-kDa heat shock protein modulates allograft rejection. (4/1550)
Allograft rejection is a process of immune reactivity triggered by foreign transplantation antigens. We now demonstrate that the 60-kDa heat shock protein (hsp60), a molecule that is identical in the donor and the recipient, can regulate allograft immunity. In wild-type mice, hsp60 expression was greatly enhanced in allografts being rejected. By using MHC class II (Ealpha) promoter hsp60 transgenic mice either as donors of skin with enhanced expression of hsp60, or as allograft recipients with decreased hsp60 autoimmunity, we found that augmented expression of mouse hsp60 in the allograft accelerated its rejection, whereas reduced autoimmunity to mouse hsp60 in graft recipients delayed the process. Moreover, in nontransgenic mice, therapeutic administration of hsp60 or hsp60 peptides, known to modulate naturally occurring hsp60 autoimmunity, led to delayed allograft rejection. Thus, we demonstrate that hsp60 expression and hsp60 autoimmunity can influence and modify the immune response to foreign antigens. Hence, autoimmunity to self-hsp60 epitopes is not necessarily an aberration, but may serve physiologically and therapeutically to modulate foreign immunity. (+info)Cell-surface expression and alloantigenic function of a human nonclassical class I molecule (HLA-E) in transgenic mice. (5/1550)
We have introduced the gene (E*01033) encoding the heavy chain of the human nonclassical MHC class I Ag, HLA-E, into the mouse genome. Two founder mice carry a 21-kb fragment, the others bear an 8-kb fragment. Each of the founder mice was mated to mice of an already established C57BL/10 transgenic line expressing human beta2-microglobulin (beta2m). Cell surface HLA-E was detected on lymph node cells by flow cytometry only in the presence of endogenous human beta2m. However, HLA-E-reactive mouse CTL (H-2-unrestricted) lysed efficiently the target cells originating from HLA-E transgenic mice without human beta2m, showing that the HLA-E protein can be transported to the cell surface in the absence of human beta2m, presumably by association with murine beta2m. Rejection of skin grafts from HLA-E transgenic mice demonstrates that HLA-E behaves as a transplantation Ag in mice. HLA-E transgenic spleen cells are effective in stimulating an allogeneic CTL response in normal and human classical class I (HLA-B27) transgenic mice. Furthermore, results from split-well analysis indicate that the majority of the primary in vivo-induced CTL recognizes HLA-E as an intact molecule (H-2-unrestricted recognition) and not as an HLA-E-derived peptide presented by a mouse MHC molecule, although a small fraction (ranging from 4 to 21%) of the primary in vivo-induced CTL is able to recognize HLA-E in an H-2-restricted manner. Based on these observations, we conclude that HLA-E exhibits alloantigenic properties that are indistinguishable from classical HLA class I molecules when expressed in transgenic mice. (+info)Human CD4+ T cells mediate rejection of porcine xenografts. (6/1550)
It has previously been demonstrated that xenograft rejection in rodents is dependent on CD4+ T cells. However, because of the lack of an appropriate in vivo model, little is known about the cellular basis of human T cell-mediated rejection of xenografts. In this study, we have evaluated the ability of human T cells to mediate rejection of porcine skin grafts in a novel in vivo experimental system using immunodeficient mice as recipients. Recombinase-activating gene-1-deficient mice (R-) lacking mature B and T cells were grafted with porcine skin and received human lymphocytes stimulated in vitro with irradiated porcine PBMC. Skin grafts on mice given either unseparated, activated human lymphocytes, or NK cell-depleted lymphocyte populations were rejected within 18 days after adoptive cell transfer. In contrast, skin grafts on mice given T cell-depleted human lymphocytes or saline showed no gross or histologic evidence of rejection up to 100 days after adoptive transfer. Purified CD4+ T cells were also able to mediate rejection of porcine skin grafts. These data suggest that human CD4+ T cells are sufficient to induce rejection of porcine xenografts. Thus, strategies directed toward CD4+ T cells may effectively prevent cellular rejection of porcine xenografts in humans. (+info)Importance of intrathymic mixed chimerism for the maintenance of skin allograft tolerance across fully allogeneic antigens in mice. (7/1550)
In B6 (H-2b) mice that had been given, neonatally, 1x108 B6AKF1 spleen cells intraperitoneally (i.p.), only a moderate prolongation of donor (AKR:H-2k) skin graft survival was observed. In such B6 mice, no mixed lymphocyte reaction (MLR) to AKR could be detected on day 35 (35 days after birth), but it was clearly evident on day 84. Similarly, neither Vbeta6+ (reactive to MTV-7-encoded antigens) nor Vbeta11+ (reactive to I-E+MTV-derived superantigens) T cells were detected on day 35, but both were clearly evident on day 84 in both the thymus and the lymph nodes, thus indicating the breakdown of intrathymic mixed chimerism at the antigen-presenting cell level. Furthermore, by day 84, all skin grafts from AKR had already been rejected in such B6 mice. In the periphery, however, Vbeta6+, but not Vbeta11+, T cells were clonally anergic on day 84, based on a stimulation assay with anti-T-cell receptor (TCR) monoclonal antibody (mAb), thus suggesting that tolerance to some antigens, but not to others, may be induced by the clonal anergy in fully allogeneic combinations, and that the clonal anergic state may be masked by other proliferative responses. These results therefore indicate the importance of intrathymic mixed chimerism (central tolerance) and the limitations of clonal anergy (peripheral tolerance) in maintaining tolerance across fully allogeneic antigen barriers. (+info)NOD mice have a generalized defect in their response to transplantation tolerance induction. (8/1550)
A protocol consisting of a single donor-specific transfusion (DST) plus a brief course of anti-CD154 monoclonal antibody (anti-CD40 ligand mAb) induces permanent islet allograft survival in chemically diabetic mice, but its efficacy in mice with autoimmune diabetes is unknown. Confirming a previous report, we first observed that treatment of young female NOD mice with anti-CD154 mAb reduced the frequency of diabetes through 1 year of age to 43%, compared with 73% in untreated controls. We also confirmed that spontaneously diabetic NOD mice transplanted with syngeneic (NOD-Prkdc(scid)/Prkdc(scid)) or allogeneic (BALB/c) islets rapidly reject their grafts. Graft survival was not prolonged, however, by pretreatment with either anti-CD154 mAb alone or anti-CD154 mAb plus DST. In addition, allograft rejection in NOD mice was not restricted to islet grafts. Anti-CD154 mAb plus DST treatment failed to prolong skin allograft survival in nondiabetic male NOD mice. The inability to induce transplantation tolerance in NOD (H2g7) mice was associated with non-major histocompatibility complex (MHC) genes. Treatment with DST and anti-CD154 mAb prolonged skin allograft survival in both C57BL/6 (H2b) and C57BL/6.NOD-H2g7 mice, but it was ineffective in NOD, NOD.SWR-H2q, and NOR (H2g7) mice. Mitogen-stimulated interleukin-1beta production by antigen-presenting cells was greater in strains susceptible to tolerance induction than in the strains resistant to tolerance induction. The results suggest the existence of a general defect in tolerance mechanisms in NOD mice. This genetic defect involves defective antigen-presenting cell maturation, leads to spontaneous autoimmune diabetes in the presence of the H2g7 MHC, and precludes the induction of transplantation tolerance irrespective of MHC haplotype. Promising islet transplantation methods based on overcoming the alloimmune response by interference with costimulation may require modification or amplification for use in the setting of autoimmune diabetes. (+info)Skin transplantation, also known as skin grafting, is a surgical procedure that involves the removal of healthy skin from one part of the body (donor site) and its transfer to another site (recipient site) that has been damaged or lost due to various reasons such as burns, injuries, infections, or diseases. The transplanted skin can help in healing wounds, restoring functionality, and improving the cosmetic appearance of the affected area. There are different types of skin grafts, including split-thickness grafts, full-thickness grafts, and composite grafts, which vary in the depth and size of the skin removed and transplanted. The success of skin transplantation depends on various factors, including the size and location of the wound, the patient's overall health, and the availability of suitable donor sites.
Homologous transplantation is a type of transplant surgery where organs or tissues are transferred between two genetically non-identical individuals of the same species. The term "homologous" refers to the similarity in structure and function of the donated organ or tissue to the recipient's own organ or tissue.
For example, a heart transplant from one human to another is an example of homologous transplantation because both organs are hearts and perform the same function. Similarly, a liver transplant, kidney transplant, lung transplant, and other types of organ transplants between individuals of the same species are also considered homologous transplantations.
Homologous transplantation is in contrast to heterologous or xenogeneic transplantation, where organs or tissues are transferred from one species to another, such as a pig heart transplanted into a human. Homologous transplantation is more commonly performed than heterologous transplantation due to the increased risk of rejection and other complications associated with xenogeneic transplants.
Graft rejection is an immune response that occurs when transplanted tissue or organ (the graft) is recognized as foreign by the recipient's immune system, leading to the activation of immune cells to attack and destroy the graft. This results in the failure of the transplant and the need for additional medical intervention or another transplant. There are three types of graft rejection: hyperacute, acute, and chronic. Hyperacute rejection occurs immediately or soon after transplantation due to pre-existing antibodies against the graft. Acute rejection typically occurs within weeks to months post-transplant and is characterized by the infiltration of T-cells into the graft. Chronic rejection, which can occur months to years after transplantation, is a slow and progressive process characterized by fibrosis and tissue damage due to ongoing immune responses against the graft.
Graft survival, in medical terms, refers to the success of a transplanted tissue or organ in continuing to function and integrate with the recipient's body over time. It is the opposite of graft rejection, which occurs when the recipient's immune system recognizes the transplanted tissue as foreign and attacks it, leading to its failure.
Graft survival depends on various factors, including the compatibility between the donor and recipient, the type and location of the graft, the use of immunosuppressive drugs to prevent rejection, and the overall health of the recipient. A successful graft survival implies that the transplanted tissue or organ has been accepted by the recipient's body and is functioning properly, providing the necessary physiological support for the recipient's survival and improved quality of life.
Liver transplantation is a surgical procedure in which a diseased or failing liver is replaced with a healthy one from a deceased donor or, less commonly, a portion of a liver from a living donor. The goal of the procedure is to restore normal liver function and improve the patient's overall health and quality of life.
Liver transplantation may be recommended for individuals with end-stage liver disease, acute liver failure, certain genetic liver disorders, or liver cancers that cannot be treated effectively with other therapies. The procedure involves complex surgery to remove the diseased liver and implant the new one, followed by a period of recovery and close medical monitoring to ensure proper function and minimize the risk of complications.
The success of liver transplantation has improved significantly in recent years due to advances in surgical techniques, immunosuppressive medications, and post-transplant care. However, it remains a major operation with significant risks and challenges, including the need for lifelong immunosuppression to prevent rejection of the new liver, as well as potential complications such as infection, bleeding, and organ failure.
BALB/c is an inbred strain of laboratory mouse that is widely used in biomedical research. The strain was developed at the Institute of Cancer Research in London by Henry Baldwin and his colleagues in the 1920s, and it has since become one of the most commonly used inbred strains in the world.
BALB/c mice are characterized by their black coat color, which is determined by a recessive allele at the tyrosinase locus. They are also known for their docile and friendly temperament, making them easy to handle and work with in the laboratory.
One of the key features of BALB/c mice that makes them useful for research is their susceptibility to certain types of tumors and immune responses. For example, they are highly susceptible to developing mammary tumors, which can be induced by chemical carcinogens or viral infection. They also have a strong Th2-biased immune response, which makes them useful models for studying allergic diseases and asthma.
BALB/c mice are also commonly used in studies of genetics, neuroscience, behavior, and infectious diseases. Because they are an inbred strain, they have a uniform genetic background, which makes it easier to control for genetic factors in experiments. Additionally, because they have been bred in the laboratory for many generations, they are highly standardized and reproducible, making them ideal subjects for scientific research.
Kidney transplantation is a surgical procedure where a healthy kidney from a deceased or living donor is implanted into a patient with end-stage renal disease (ESRD) or permanent kidney failure. The new kidney takes over the functions of filtering waste and excess fluids from the blood, producing urine, and maintaining the body's electrolyte balance.
The transplanted kidney is typically placed in the lower abdomen, with its blood vessels connected to the recipient's iliac artery and vein. The ureter of the new kidney is then attached to the recipient's bladder to ensure proper urine flow. Following the surgery, the patient will require lifelong immunosuppressive therapy to prevent rejection of the transplanted organ by their immune system.
C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.
The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.
C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.
One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.
Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.
Bone marrow transplantation (BMT) is a medical procedure in which damaged or destroyed bone marrow is replaced with healthy bone marrow from a donor. Bone marrow is the spongy tissue inside bones that produces blood cells. The main types of BMT are autologous, allogeneic, and umbilical cord blood transplantation.
In autologous BMT, the patient's own bone marrow is used for the transplant. This type of BMT is often used in patients with lymphoma or multiple myeloma who have undergone high-dose chemotherapy or radiation therapy to destroy their cancerous bone marrow.
In allogeneic BMT, bone marrow from a genetically matched donor is used for the transplant. This type of BMT is often used in patients with leukemia, lymphoma, or other blood disorders who have failed other treatments.
Umbilical cord blood transplantation involves using stem cells from umbilical cord blood as a source of healthy bone marrow. This type of BMT is often used in children and adults who do not have a matched donor for allogeneic BMT.
The process of BMT typically involves several steps, including harvesting the bone marrow or stem cells from the donor, conditioning the patient's body to receive the new bone marrow or stem cells, transplanting the new bone marrow or stem cells into the patient's body, and monitoring the patient for signs of engraftment and complications.
BMT is a complex and potentially risky procedure that requires careful planning, preparation, and follow-up care. However, it can be a life-saving treatment for many patients with blood disorders or cancer.
In medical terms, the skin is the largest organ of the human body. It consists of two main layers: the epidermis (outer layer) and dermis (inner layer), as well as accessory structures like hair follicles, sweat glands, and oil glands. The skin plays a crucial role in protecting us from external factors such as bacteria, viruses, and environmental hazards, while also regulating body temperature and enabling the sense of touch.
Hematopoietic Stem Cell Transplantation (HSCT) is a medical procedure where hematopoietic stem cells (immature cells that give rise to all blood cell types) are transplanted into a patient. This procedure is often used to treat various malignant and non-malignant disorders affecting the hematopoietic system, such as leukemias, lymphomas, multiple myeloma, aplastic anemia, inherited immune deficiency diseases, and certain genetic metabolic disorders.
The transplantation can be autologous (using the patient's own stem cells), allogeneic (using stem cells from a genetically matched donor, usually a sibling or unrelated volunteer), or syngeneic (using stem cells from an identical twin).
The process involves collecting hematopoietic stem cells, most commonly from the peripheral blood or bone marrow. The collected cells are then infused into the patient after the recipient's own hematopoietic system has been ablated (or destroyed) using high-dose chemotherapy and/or radiation therapy. This allows the donor's stem cells to engraft, reconstitute, and restore the patient's hematopoietic system.
HSCT is a complex and potentially risky procedure with various complications, including graft-versus-host disease, infections, and organ damage. However, it offers the potential for cure or long-term remission in many patients with otherwise fatal diseases.
Heart transplantation is a surgical procedure where a diseased, damaged, or failing heart is removed and replaced with a healthy donor heart. This procedure is usually considered as a last resort for patients with end-stage heart failure or severe coronary artery disease who have not responded to other treatments. The donor heart typically comes from a brain-dead individual whose family has agreed to donate their loved one's organs for transplantation. Heart transplantation is a complex and highly specialized procedure that requires a multidisciplinary team of healthcare professionals, including cardiologists, cardiac surgeons, anesthesiologists, perfusionists, nurses, and other support staff. The success rates for heart transplantation have improved significantly over the past few decades, with many patients experiencing improved quality of life and increased survival rates. However, recipients of heart transplants require lifelong immunosuppressive therapy to prevent rejection of the donor heart, which can increase the risk of infections and other complications.
Autologous transplantation is a medical procedure where cells, tissues, or organs are removed from a person, stored and then returned back to the same individual at a later time. This is different from allogeneic transplantation where the tissue or organ is obtained from another donor. The term "autologous" is derived from the Greek words "auto" meaning self and "logos" meaning study.
In autologous transplantation, the patient's own cells or tissues are used to replace or repair damaged or diseased ones. This reduces the risk of rejection and eliminates the need for immunosuppressive drugs, which are required in allogeneic transplants to prevent the body from attacking the foreign tissue.
Examples of autologous transplantation include:
* Autologous bone marrow or stem cell transplantation, where stem cells are removed from the patient's blood or bone marrow, stored and then reinfused back into the same individual after high-dose chemotherapy or radiation therapy to treat cancer.
* Autologous skin grafting, where a piece of skin is taken from one part of the body and transplanted to another area on the same person.
* Autologous chondrocyte implantation, where cartilage cells are harvested from the patient's own knee, cultured in a laboratory and then implanted back into the knee to repair damaged cartilage.
Lung transplantation is a surgical procedure where one or both diseased lungs are removed and replaced with healthy lungs from a deceased donor. It is typically considered as a treatment option for patients with end-stage lung diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, idiopathic pulmonary fibrosis, and alpha-1 antitrypsin deficiency, who have exhausted all other medical treatments and continue to suffer from severe respiratory failure.
The procedure involves several steps, including evaluating the patient's eligibility for transplantation, matching the donor's lung size and blood type with the recipient, and performing the surgery under general anesthesia. After the surgery, patients require close monitoring and lifelong immunosuppressive therapy to prevent rejection of the new lungs.
Lung transplantation can significantly improve the quality of life and survival rates for some patients with end-stage lung disease, but it is not without risks, including infection, bleeding, and rejection. Therefore, careful consideration and thorough evaluation are necessary before pursuing this treatment option.
Stem cell transplantation is a medical procedure where stem cells, which are immature and unspecialized cells with the ability to differentiate into various specialized cell types, are introduced into a patient. The main purpose of this procedure is to restore the function of damaged or destroyed tissues or organs, particularly in conditions that affect the blood and immune systems, such as leukemia, lymphoma, aplastic anemia, and inherited metabolic disorders.
There are two primary types of stem cell transplantation: autologous and allogeneic. In autologous transplantation, the patient's own stem cells are collected, stored, and then reinfused back into their body after high-dose chemotherapy or radiation therapy to destroy the diseased cells. In allogeneic transplantation, stem cells are obtained from a donor (related or unrelated) whose human leukocyte antigen (HLA) type closely matches that of the recipient.
The process involves several steps: first, the patient undergoes conditioning therapy to suppress their immune system and make space for the new stem cells. Then, the harvested stem cells are infused into the patient's bloodstream, where they migrate to the bone marrow and begin to differentiate and produce new blood cells. This procedure requires close monitoring and supportive care to manage potential complications such as infections, graft-versus-host disease, and organ damage.
Transplantation conditioning, also known as preparative regimen or immunoablative therapy, refers to the use of various treatments prior to transplantation of cells, tissues or organs. The main goal of transplantation conditioning is to suppress the recipient's immune system, allowing for successful engraftment and minimizing the risk of rejection of the donor tissue.
There are two primary types of transplantation conditioning: myeloablative and non-myeloablative.
1. Myeloablative conditioning is a more intensive regimen that involves the use of high-dose chemotherapy, radiation therapy or both. This approach eliminates not only immune cells but also stem cells in the bone marrow, requiring the recipient to receive a hematopoietic cell transplant (HCT) from the donor to reconstitute their blood and immune system.
2. Non-myeloablative conditioning is a less intensive regimen that primarily targets immune cells while sparing the stem cells in the bone marrow. This approach allows for mixed chimerism, where both recipient and donor immune cells coexist, reducing the risk of severe complications associated with myeloablative conditioning.
The choice between these two types of transplantation conditioning depends on various factors, including the type of transplant, patient's age, overall health, and comorbidities. Both approaches carry risks and benefits, and the decision should be made carefully by a multidisciplinary team of healthcare professionals in consultation with the patient.
Organ transplantation is a surgical procedure where an organ or tissue from one person (donor) is removed and placed into another person (recipient) whose organ or tissue is not functioning properly or has been damaged beyond repair. The goal of this complex procedure is to replace the non-functioning organ with a healthy one, thereby improving the recipient's quality of life and overall survival.
Organs that can be transplanted include the heart, lungs, liver, kidneys, pancreas, and intestines. Tissues such as corneas, skin, heart valves, and bones can also be transplanted. The donor may be deceased or living, depending on the type of organ and the medical circumstances.
Organ transplantation is a significant and life-changing event for both the recipient and their families. It requires careful evaluation, matching, and coordination between the donor and recipient, as well as rigorous post-transplant care to ensure the success of the procedure and minimize the risk of rejection.
Pancreas transplantation is a surgical procedure that involves implanting a healthy pancreas from a deceased donor into a recipient with diabetes. The primary goal of this procedure is to restore the recipient's insulin production and eliminate the need for insulin injections, thereby improving their quality of life and reducing the risk of long-term complications associated with diabetes.
There are three main types of pancreas transplantation:
1. Simultaneous pancreas-kidney (SPK) transplantation: This is the most common type of pancreas transplant, performed simultaneously with a kidney transplant in patients with diabetes and end-stage renal disease (ESRD). The new pancreas not only restores insulin production but also helps prevent further kidney damage.
2. Pancreas after kidney (PAK) transplantation: In this procedure, a patient receives a kidney transplant first, followed by a pancreas transplant at a later time. This is typically performed in patients who have already undergone a successful kidney transplant and wish to improve their diabetes management.
3. Pancreas transplantation alone (PTA): In rare cases, a pancreas transplant may be performed without a concurrent kidney transplant. This is usually considered for patients with brittle diabetes who experience severe hypoglycemic episodes despite optimal medical management and lifestyle modifications.
The success of pancreas transplantation has significantly improved over the years, thanks to advancements in surgical techniques, immunosuppressive medications, and post-transplant care. However, it is essential to weigh the benefits against the risks, such as potential complications related to surgery, infection, rejection, and long-term use of immunosuppressive drugs. Ultimately, the decision to undergo pancreas transplantation should be made in consultation with a multidisciplinary team of healthcare professionals, considering each patient's unique medical history and personal circumstances.
Islets of Langerhans transplantation is a surgical procedure that involves the transplantation of isolated islets from a deceased donor's pancreas into another person with type 1 diabetes. The islets of Langerhans are clusters of cells within the pancreas that produce hormones, including insulin, which regulates blood sugar levels.
In type 1 diabetes, the body's immune system mistakenly attacks and destroys these insulin-producing cells, leading to high blood sugar levels. Islet transplantation aims to replace the damaged islets with healthy ones from a donor, allowing the recipient's body to produce and regulate its own insulin again.
The procedure involves extracting the islets from the donor pancreas and infusing them into the recipient's liver through a small incision in the abdomen. Once inside the liver, the islets can sense glucose levels in the bloodstream and release insulin as needed to maintain normal blood sugar levels.
Islet transplantation has shown promising results in improving blood sugar control and reducing the risk of severe hypoglycemia (low blood sugar) in people with type 1 diabetes. However, it requires long-term immunosuppressive therapy to prevent rejection of the transplanted islets, which can have side effects and increase the risk of infections.
A tissue donor is an individual who has agreed to allow organs and tissues to be removed from their body after death for the purpose of transplantation to restore the health or save the life of another person. The tissues that can be donated include corneas, heart valves, skin, bone, tendons, ligaments, veins, and cartilage. These tissues can enhance the quality of life for many recipients and are often used in reconstructive surgeries. It is important to note that tissue donation does not interfere with an open casket funeral or other cultural or religious practices related to death and grieving.
Transplantation is a medical procedure where an organ or tissue is removed from one person (the donor) and placed into another person (the recipient) for the purpose of replacing the recipient's damaged or failing organ or tissue with a functioning one. The goal of transplantation is to restore normal function, improve quality of life, and extend lifespan in individuals with organ failure or severe tissue damage. Common types of transplants include kidney, liver, heart, lung, pancreas, small intestine, and bone marrow transplantations. The success of a transplant depends on various factors, including the compatibility between the donor and recipient, the health of both individuals, and the effectiveness of immunosuppressive therapy to prevent rejection of the transplanted organ or tissue.
Transplantation Immunology is a branch of medicine that deals with the immune responses occurring between a transplanted organ or tissue and the recipient's body. It involves understanding and managing the immune system's reaction to foreign tissue, which can lead to rejection of the transplanted organ. This field also studies the use of immunosuppressive drugs to prevent rejection and the potential risks and side effects associated with their use. The main goal of transplantation immunology is to find ways to promote the acceptance of transplanted tissue while minimizing the risk of infection and other complications.
Cell transplantation is the process of transferring living cells from one part of the body to another or from one individual to another. In medicine, cell transplantation is often used as a treatment for various diseases and conditions, including neurodegenerative disorders, diabetes, and certain types of cancer. The goal of cell transplantation is to replace damaged or dysfunctional cells with healthy ones, thereby restoring normal function to the affected area.
In the context of medical research, cell transplantation may involve the use of stem cells, which are immature cells that have the ability to develop into many different types of specialized cells. Stem cell transplantation has shown promise in the treatment of a variety of conditions, including spinal cord injuries, stroke, and heart disease.
It is important to note that cell transplantation carries certain risks, such as immune rejection and infection. As such, it is typically reserved for cases where other treatments have failed or are unlikely to be effective.
Skin diseases, also known as dermatological conditions, refer to any medical condition that affects the skin, which is the largest organ of the human body. These diseases can affect the skin's function, appearance, or overall health. They can be caused by various factors, including genetics, infections, allergies, environmental factors, and aging.
Skin diseases can present in many different forms, such as rashes, blisters, sores, discolorations, growths, or changes in texture. Some common examples of skin diseases include acne, eczema, psoriasis, dermatitis, fungal infections, viral infections, bacterial infections, and skin cancer.
The symptoms and severity of skin diseases can vary widely depending on the specific condition and individual factors. Some skin diseases are mild and can be treated with over-the-counter medications or topical creams, while others may require more intensive treatments such as prescription medications, light therapy, or even surgery.
It is important to seek medical attention if you experience any unusual or persistent changes in your skin, as some skin diseases can be serious or indicative of other underlying health conditions. A dermatologist is a medical doctor who specializes in the diagnosis and treatment of skin diseases.
A transplantation chimera is a rare medical condition that occurs after an organ or tissue transplant, where the recipient's body accepts and integrates the donor's cells or tissues to such an extent that the two sets of DNA coexist and function together. This phenomenon can lead to the presence of two different genetic profiles in one individual.
In some cases, this may result in the development of donor-derived cells or organs within the recipient's body, which can express the donor's unique genetic traits. Transplantation chimerism is more commonly observed in bone marrow transplants, where the donor's immune cells can repopulate and establish themselves within the recipient's bone marrow and bloodstream.
It is important to note that while transplantation chimerism can be beneficial for the success of the transplant, it may also pose some risks, such as an increased likelihood of developing graft-versus-host disease (GVHD), where the donor's immune cells attack the recipient's tissues.
Skin aging, also known as cutaneous aging, is a complex and multifactorial process characterized by various visible changes in the skin's appearance and function. It can be divided into two main types: intrinsic (chronological or natural) aging and extrinsic (environmental) aging.
Intrinsic aging is a genetically determined and time-dependent process that results from internal factors such as cellular metabolism, hormonal changes, and genetic predisposition. The primary features of intrinsic aging include gradual thinning of the epidermis and dermis, decreased collagen and elastin production, reduced skin cell turnover, and impaired wound healing. Clinically, these changes present as fine wrinkles, dryness, loss of elasticity, and increased fragility of the skin.
Extrinsic aging, on the other hand, is caused by external factors such as ultraviolet (UV) radiation, pollution, smoking, alcohol consumption, and poor nutrition. Exposure to these environmental elements leads to oxidative stress, inflammation, and DNA damage, which accelerate the aging process. The main features of extrinsic aging are coarse wrinkles, pigmentary changes (e.g., age spots, melasma), irregular texture, skin laxity, and increased risk of developing skin cancers.
It is important to note that intrinsic and extrinsic aging processes often interact and contribute to the overall appearance of aged skin. A comprehensive approach to skincare should address both types of aging to maintain healthy and youthful-looking skin.
Skin neoplasms refer to abnormal growths or tumors in the skin that can be benign (non-cancerous) or malignant (cancerous). They result from uncontrolled multiplication of skin cells, which can form various types of lesions. These growths may appear as lumps, bumps, sores, patches, or discolored areas on the skin.
Benign skin neoplasms include conditions such as moles, warts, and seborrheic keratoses, while malignant skin neoplasms are primarily classified into melanoma, squamous cell carcinoma, and basal cell carcinoma. These three types of cancerous skin growths are collectively known as non-melanoma skin cancers (NMSCs). Melanoma is the most aggressive and dangerous form of skin cancer, while NMSCs tend to be less invasive but more common.
It's essential to monitor any changes in existing skin lesions or the appearance of new growths and consult a healthcare professional for proper evaluation and treatment if needed.
Immunosuppressive agents are medications that decrease the activity of the immune system. They are often used to prevent the rejection of transplanted organs and to treat autoimmune diseases, where the immune system mistakenly attacks the body's own tissues. These drugs work by interfering with the immune system's normal responses, which helps to reduce inflammation and damage to tissues. However, because they suppress the immune system, people who take immunosuppressive agents are at increased risk for infections and other complications. Examples of immunosuppressive agents include corticosteroids, azathioprine, cyclophosphamide, mycophenolate mofetil, tacrolimus, and sirolimus.
Graft-versus-host disease (GVHD) is a condition that can occur after an allogeneic hematopoietic stem cell transplantation (HSCT), where the donated immune cells (graft) recognize the recipient's tissues (host) as foreign and attack them. This results in inflammation and damage to various organs, particularly the skin, gastrointestinal tract, and liver.
Acute GVHD typically occurs within 100 days of transplantation and is characterized by symptoms such as rash, diarrhea, and liver dysfunction. Chronic GVHD, on the other hand, can occur after 100 days or even years post-transplant and may present with a wider range of symptoms, including dry eyes and mouth, skin changes, lung involvement, and issues with mobility and flexibility in joints.
GVHD is a significant complication following allogeneic HSCT and can have a substantial impact on the patient's quality of life and overall prognosis. Preventative measures, such as immunosuppressive therapy, are often taken to reduce the risk of GVHD, but its management remains a challenge in transplant medicine.
Isogeneic transplantation is a type of transplant where the donor and recipient are genetically identical, meaning they are identical twins or have the same genetic makeup. In this case, the immune system recognizes the transplanted organ or tissue as its own and does not mount an immune response to reject it. This reduces the need for immunosuppressive drugs, which are typically required in other types of transplantation to prevent rejection.
In medical terms, isogeneic transplantation is defined as the transfer of genetic identical tissues or organs between genetically identical individuals, resulting in minimal risk of rejection and no need for immunosuppressive therapy.
Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.
A living donor is a person who voluntarily donates an organ or part of an organ to another person while they are still alive. This can include donations such as a kidney, liver lobe, lung, or portion of the pancreas or intestines. The donor and recipient typically undergo medical evaluation and compatibility testing to ensure the best possible outcome for the transplantation procedure. Living donation is regulated by laws and ethical guidelines to ensure that donors are fully informed and making a voluntary decision.
Heterotopic transplantation is a type of organ or tissue transplant where the graft is placed in a different location from where it normally resides while still maintaining its original site. This is often done to supplement the function of the existing organ rather than replacing it. A common example of heterotopic transplantation is a heart transplant, where the donor's heart is placed in a new location in the recipient's body, while the recipient's own heart remains in place but is typically nonfunctional. This allows for the possibility of returning the function of the recipient's heart if the transplanted organ fails.
In heterotopic kidney transplantation, the donor kidney is placed in a different location, usually in the lower abdomen, while the recipient's own kidneys are left in place. This approach can be beneficial for recipients with poor renal function or other medical conditions that make traditional kidney transplantation too risky.
Heterotopic transplantation is also used in liver transplantation, where a portion of the donor liver is placed in a different location, typically in the recipient's abdomen, while the recipient's own liver remains in place. This approach can be useful for recipients with acute liver failure or other conditions that make traditional liver transplantation too risky.
One advantage of heterotopic transplantation is that it allows for the possibility of returning the function of the recipient's organ if the transplanted organ fails, as well as reducing the risk of rejection and improving overall outcomes for the recipient. However, this approach also has some disadvantages, such as increased complexity of the surgical procedure, potential for complications related to the placement of the graft, and the need for ongoing immunosuppression therapy to prevent rejection.
Cord blood stem cell transplantation is a medical procedure that involves the infusion of stem cells derived from the umbilical cord blood into a patient. These stem cells, specifically hematopoietic stem cells, have the ability to differentiate into various types of blood cells, including red and white blood cells and platelets.
Cord blood stem cell transplantation is often used as a treatment for patients with various malignant and non-malignant disorders, such as leukemia, lymphoma, sickle cell disease, and metabolic disorders. The procedure involves collecting cord blood from the umbilical cord and placenta after the birth of a baby, processing and testing it for compatibility with the recipient's immune system, and then infusing it into the patient through a vein in a process similar to a blood transfusion.
The advantages of using cord blood stem cells include their availability, low risk of transmission of infectious diseases, and reduced risk of graft-versus-host disease compared to other sources of hematopoietic stem cells, such as bone marrow or peripheral blood. However, the number of stem cells in a cord blood unit is generally lower than that found in bone marrow or peripheral blood, which can limit its use in some patients, particularly adults.
Overall, cord blood stem cell transplantation is an important and promising area of regenerative medicine, offering hope for patients with a wide range of disorders.
Heart-lung transplantation is a surgical procedure where both the heart and lungs of a patient are replaced with those from a deceased donor. This complex and highly specialized surgery is typically considered as a last resort for patients suffering from end-stage lung or heart-lung diseases, such as cystic fibrosis, pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), or certain forms of congenital heart disease, who have exhausted all other treatment options and face imminent death.
The procedure involves removing the patient's diseased heart and lungs en bloc, followed by implanting the donor's heart and lungs in their place. The surgery requires a skilled multidisciplinary team of cardiothoracic surgeons, anesthesiologists, perfusionists, transplant coordinators, and intensive care specialists.
Following the transplantation, patients require lifelong immunosuppressive therapy to prevent rejection of the transplanted organs. Despite the significant risks associated with this procedure, including infection, bleeding, and rejection, heart-lung transplantation can significantly improve both survival and quality of life for carefully selected patients with advanced heart-lung disease.