52 research outputs found
Pancreas Retrieval for Whole Organ and Islet Cell Transplantation
For more than five decades, we have been refining advances in pancreas whole organ and islet cell transplantation as clinical therapies to treat the ever-increasing number of patients suffering from type-1-diabetes. Research and clinical practice have contributed to making both whole organ and cellular transplantation viable therapeutic options for a broader range of patients. Furthermore, both forms of clinical transplantation results have progressively improved, due to the ongoing refinement of organ donation and its various technical processes, combined with the evolution of immunosuppression and patient care now offering excellent long-term treatment for both type-1-diabetes and concomitant renal failure. This chapter provides an overview on how this has been undertaken and achieved over decades to ultimately provide outstanding outcomes on par with other organ transplantation results. Briefly, we cover the history of pancreas retrieval procedures, the importance of donor selection, the intricate processes of the organ donor operation, preservation of the pancreas, and the ideal ways to best improve outcomes for transplantation. Improving and providing the optimal donor and preservation conditions underpinning the success of subsequent whole pancreas or islet transplantation as a safe, effective, and feasible therapeutic option for an increasing number of patients suffering from type-1-diabetes
Epigenetic and transcriptome profiling identifies a population of visceral adipose-derived progenitor cells with potential to differentiate into an endocrine pancreatic lineage
Type 1 diabetes (T1D) is characterized by the loss of insulin-producing β-cells in the pancreas. T1D can be treated using cadaveric islet transplantation, but this therapy is severely limited by a lack of pancreas donors. To develop an alternative cell source for transplantation therapy, we carried out the epigenetic characterization in nine different adult mouse tissues and identified visceral adipose-derived progenitors as a candidate cell population. Chromatin conformation, assessed using chromatin immunoprecipitation (ChIP) sequencing and validated by ChIP-polymerase chain reaction (PCR) at key endocrine pancreatic gene promoters, revealed similarities between visceral fat and endocrine pancreas. Multiple techniques involving quantitative PCR, in-situ PCR, confocal microscopy, and flow cytometry confirmed the presence of measurable (2–1000-fold over detectable limits) pancreatic gene transcripts and mesenchymal progenitor cell markers (CD73, CD90 and CD105; >98%) in visceral adipose tissue-derived mesenchymal cells (AMCs). The differentiation potential of AMCs was explored in transgenic reporter mice expressing green fluorescent protein (GFP) under the regulation of the Pdx1 (pancreatic and duodenal homeobox-1) gene promoter. GFP expression was measured as an index of Pdx1 promoter activity to optimize culture conditions for endocrine pancreatic differentiation. Differentiated AMCs demonstrated their capacity to induce pancreatic endocrine genes as evidenced by increased GFP expression and validated using TaqMan real-time PCR (at least 2–200-fold relative to undifferentiated AMCs). Human AMCs differentiated using optimized protocols continued to produce insulin following transplantation in NOD/SCID mice. Our studies provide a systematic analysis of potential islet progenitor populations using genome-wide profiling studies and characterize visceral adipose-derived cells for replacement therapy in diabetes
Current status of islet xenotransplantation
Cell therapy for Type 1 diabetes (T1D) utilizing islet cell transplantation can successfully restore endogenous insulin production in affected patients. Islet cell engraftment and survival are conditional on the use of efficacious anti-rejection therapies and on the availability of healthy donor cells. The scarcity of healthy human donor pancreata is a limiting factor in providing sufficient tissue to meet the demand for islet transplantation worldwide. A potential alternative to the use of cadaveric human donor pancreases is the use of animal sourced islets.Pancreatic islets obtained from pigs have emerged as an alternative to human tissues due to their great availability, physiological similarities to human islets, including the time-tested use of porcine insulin in diabetic patients and the ability to genetically modify the donor source.The evolution of refined, efficacious immunosuppressive therapies with reduced toxicity, improvements in donor management and genetic manipulation of the donor have all contributed to facilitate long-term function in pre-clinical models of pig islet grafts in non-human primates.As clinical consideration for this option is growing, and trials involving the use of porcine islets have begun, more compelling experimental data suggest that the use of pig islets may soon become a viable, safe, effective and readily available treatment for insulin deficiency in T1D patients
Australia and New Zealand Islet and Pancreas Transplant Registry Annual Report 2018—Islet Donations, Islet Isolations, and Islet Transplants
Background. This is an excerpt from chapter 4 of the annual registry report from the Australia and New Zealand islet and pan- creas transplant registry. The full report is available at http://anziptr.org/reports/. Methods. We report data for all allogeneic islet isolation and transplant activity from 2002 to end 2017. Solid organ pancreas transplantation activity is reported separately. New Zealand does not have an islet transplant program. Data analysis was performed using Stata software version 14 (StataCorp, College Station, TX). Results. From 2002 to 2017, a total of 104 allogeneic islet transplants were performed in 62 recipients. Conclusions. The number of islet transplants performed in Australia was slightly lower in 2017 but continues to increase over time
Third WHO Global Consultation on regulatory requirements for xenotransplantation clinical trials, Changsha, Hunan, China December 12-14, 2018: "The 2018 Changsha Communiqué" The 10-Year Anniversary of The International Consultation on Xenotransplantation
After feedback from the working parties, the final session focused on drafting proposed revisions of the WHO documents, and resulted in the formulation of the draft “Third WHO Global Consultation on Regulatory Requirements for Xenotransplantation Clinical Trials, The 2018 Changsha Communiqué.” This draft was submitted to WHO in February 2019 for WHO and World Health Assembly consideration. If approved, the 2018 Changsha Communiqué will then be posted on the websites of WHO, IXA, and TTS, and published in Xenotransplantation. This report includes summaries of the various sessions, followed by the abstracts of invited speakers from the update sessions
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
Gene therapy in diabetes
Type 1 diabetes (T1D) is a chronic autoimmune disease, whereby auto-reactive cytotoxic T cells target and destroy insulin-secreting β-cells in pancreatic islets leading to insulin deficiency and subsequent hyperglycemia. These individuals require multiple daily insulin injections every day of their life without which they will develop life-threatening diabetic ketoacidosis (DKA) and die. Gene therapy by viral vector and non-viral transduction may be useful techniques to treat T1D as it can be applied from many different angles; such as the suppression of autoreactive T cells to prevent islet destruction (prophylactic) or the replacement of the insulin gene (post-disease). The need for a better method for providing euglycemia arose from insufficient numbers of cadaver islets for transplantation and the immunosuppression required post-transplant. Ectopic expression of insulin or islet modification have been examined, but not perfected. This review examines the various gene transfer methods, gene therapy techniques used to date and promising novel techniques for the maintenance of euglycemia in the treatment of T1D
The evolution of kidney transplantation surgery into the robotic era and its prospects for obese recipients
Robotic-assisted kidney transplantation (RAKT) represents the most recent innovation in the evolution of kidney transplantation surgery. Vascular techniques enabling kidney transplantation have existed since the early 20th century and contributed to the first successful open kidney transplant procedure in 1954. Technical advances have since facilitated minimally invasive laparoscopic and robotic techniques in live-donor surgery, and subsequently for the recipient procedure. This review follows the development of surgical techniques for kidney transplantation, with a special focus on the advent of robotic-assisted transplantation because of its potential to facilitate transplantation of those deemed previously too obese to transplant by standard means. The different techniques, indications, advantages, disadvantages, and future directions of this approach will be explored in detail. Robot-assisted kidney transplantation may become the preferred means of transplanting morbidly obese recipients, although its availability to such recipients remains extremely limited and strategies targeting weight loss pretransplantation should never be abandoned in favor of a "RAKT-first" approach
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