Pancreas transplantation

Four Decades of Research Productivity and Hot Spots in Pancreas Transplantation

Background: The field of pancreas transplantation has undergone transformative phases, progressing from its promising inception in 1966 to becoming a standard treatment for patients with insulin-dependent diabetes. This bibliometric analysis explores the progression of pancreas transplantation research over a period of four decades, mapping milestones, contributors, and emerging trends. Methods: Our bibliometric analysis utilizes the comprehensive Scopus database, which includes publication titles, author information, affiliations, abstracts, keywords, and journal details. The search strategy was centered on research related to pancreas and pancreas-kidney transplantation. The analysis encompasses the time frame spanning from 1983 to 2023, with the data extraction taking place on October 7th, 2023. Results: The analysis of 4,897 articles uncovered unique trends in the field of pancreas transplantation research. The years 1989, 1996, and 2021 saw significant increases in the number of publications, which corresponded to the responses to clinical challenges and advancements. Contributions by authors from the United States of America were the most numerous, with 1,905 publications and 49,949 citations. The research topics were highlighted by keywords such as "graft survival," "graft rejection," and" Immunosuppressive treatment." Conclusion: The fluctuations in publication trends that have been identified indicate dynamic reactions to changing priorities and challenges. Although it has limitations, this analysis provides valuable insights for researchers, clinicians, and policymakers who are dealing with the complex field of pancreas transplantation literature. Further bibliometric research may advance our knowledge and direct future initiatives in this developing field.

Neural Stem Cell-based Regenerative Therapy: A New Approach to Diabetes Treatment

Diabetes mellitus (DM) is the most common metabolic disorder that occurs due to the loss, or impaired function of insulin-secreting pancreatic beta cells, which are of two types - type 1 (T1D) and type 2 (T2D). To cure DM, the replacement of the destroyed pancreatic beta cells of islet of Langerhans is the most widely practiced treatment. For this, isolating neuronal stem cells and cultivating them as a source of renewable beta cells is a significant breakthrough in medicine. The functions, growth, and gene expression of insulin-producing pancreatic beta cells and neurons are very similar in many ways. A diabetic patient's neural stem cells (obtained from the hippocampus and olfactory bulb) can be used as a replacement source of beta cells for regenerative therapy to treat diabetes. The same protocol used to create functional neurons from progenitor cells can be used to create beta cells. Recent research suggests that replacing lost pancreatic beta cells with autologous transplantation of insulin-producing neural progenitor cells may be a perfect therapeutic strategy for diabetes, allowing for a safe and normal restoration of function and a reduction in potential risks and a long-term cure.

[Simultaneous living donor pancreas-kidney transplantation in a patient with type 1 diabetes mellitus after program hemodialysis. Case report]

Simultaneous pancreas-kidney transplantation is an effective treatment option for end-stage renal disease with diabetes mellitus. Successful simultaneous pancreas-kidney transplantation allows achieving euglycemia, stabilizing existing microvascular complications and slowing their progression, improving the patient's quality of life, lipid and calcium-phosphorus metabolism, reducing the risks of cardiovascular events. Therefore, in view of the patient's severe general condition due to prolonged intoxication, hyperglycemia and other complications of chronic kidney disease, the earliest possible surgical treatment with minimization of the patient's stay on dialysis therapy is crucial to improve the outcome of transplantation.

Ambulatory Blood Pressure Monitoring as a Useful Tool in the Cardiological Assessment of Pancreas Transplant Recipients with Type 1 Diabetes

Having the appropriate tools to identify pancreas recipients most susceptible to coronary artery disease (CAD) is crucial for pretransplant cardiological assessment. The aim of this study is to evaluate the association between blood pressure (BP) indices provided by ambulatory blood pressure monitoring (ABPM) and the prevalence of CAD in pancreas transplant candidates with type 1 diabetes (T1D). This prospective cross-sectional study included adult T1D patients referred for pretransplant cardiological assessment in our center. The study population included 86 participants with a median age of 40 (35-46) years. In multivariate logistic regression analyses, after adjusting for potential confounding factors, higher 24 h BP (systolic BP/diastolic BP/pulse pressure) (OR  =  1.063, 95% CI 1.023-1.105, p = 0.002/OR = 1.075, 95% CI 1.003-1.153, p = 0.042/OR = 1.091, 95 CI 1.037-1.147, p = 0.001, respectively) and higher daytime BP (systolic BP/diastolic BP/pulse pressure) (OR  =  1.069, 95% CI 1.027-1.113, p = 0.001/OR = 1.077, 95% CI 1.002-1.157, p = 0.043/OR = 1.11, 95% CI 1.051-1.172, p = 0.0002, respectively) were independently and significantly associated with the prevalence of CAD. Daytime pulse pressure was the strongest indicator of the prevalence of CAD among all analyzed ABPM parameters. ABPM can be used as a valuable tool to identify pancreas recipients who are most susceptible to CAD. We suggest the inclusion of ABPM in pretransplant cardiac screening in type 1 diabetes patients eligible for pancreas transplantation.

Psychological care of patients during the pancreas transplantation process: issues and prospects

Pancreas transplantation for patients with type 1 diabetes is a therapeutic option when other treatments are not effective and physical complications occur. Psychological burden is prominent in patients, and non-adherence to treatment is often one manifestation of such difficulties. Time projection is an important factor affected by chronic disease. The prospect of transplantation has the potential to repair this disruption. It could re-establish a continuity in the patient's self and history, by connecting the future to a life that was only about past and present. Taking care of oneself, adhering to treatment, being part of a long-term therapeutic project and going through transplantation are all processes that need a good ability to self-project in time. This is specifically a domain of psychotherapeutic interventions. In this article, the psychological implications of pancreas transplantation for patients and caregivers alike will be discussed, as well as the role of the psychiatrist in the transplantation process.

Impact of insulin therapy before donation on graft outcomes in pancreas transplantation: An analysis of the OPTN/UNOS database

AIMS

Information on the impact of insulin therapy before pancreas donation on pancreas outcomes is scarce. We aim to explore the influence of insulin therapy before donation on recipient and pancreas graft survival.

METHODS

Registry study including 12,841 pancreas recipients from the OPTN/UNOS registry performed between 2000 and 2017. Inverse probability of treatment weighting (IPTW) was used to account for covariate imbalance between recipients from a donor with and without insulin requirements.

RESULTS

A total of 7765 (60%) patients received a pancreas from a donor with insulin before donation (IBD). Pancreas graft survival (death-censored) was similar between recipients from IBD and non-IBD donors at 1, 5 and 10 years (89% vs 89%, 78% vs 79 and 69% vs 70%, respectively, P = 0.35). Recipients from IBD donors presented a similar 90-days pancreas graft survival. After IPTW weighting, IBD donors were neither associated with any post-transplant surgical complication (HR 1.11 [95% CI 0.98-1.24], P = 0.06), nor with risk for recipient death (HR 0.94 [95% CI 0.85-1.04], P = 0.26), nor pancreas graft failure (HR 1.06 [95% CI 0.98-1.16], P = 0.15).

CONCLUSIONS

Insulin therapy before donation in accepted pancreas donors was not associated, per se, with an impaired pancreas graft and patient survival.

Technical factors that minimize the occurrence of early graft failure in pancreas transplantation

Pancreatic transplantation is the only treatment for insulin-dependent diabetes resulting in long-term euglycemia without exogenous insulin. However, pancreatic transplantation has become debatable following the improvements in the results of islet transplantation and artificial pancreas. Therefore, surgeons who perform pancreas transplants require the best surgical technique that can minimize technical failure. We aimed to report our experiences with pancreatic transplantations. We transplanted 65 pancreatic grafts between 2015 and 2020. Except for one death due to hypoxic brain damage after surgery, no postoperative technical failure was observed. We usually perform duodeno-duodenal anastomosis using the transperitoneal approach, with retrocolic placement of the graft pancreas. There was no leakage from the duodenum even after immunologic graft failure. To prevent venous thrombosis, which is the most common cause of technical failure, we used the inferior vena cava for anastomosis and added graft venoplasty with a patch of donor vena cava or aortic interposition graft to the bench procedure; subsequently, there were no cases of technical failure due to thrombosis post-transplantation. Therefore, the 1-year graft survival (insulin-free) rate was more than 95%. The improving the surgical technique will maintain pancreatic transplantation as the best treatment for insulin-dependent diabetes. This article is protected by copyright. All rights reserved.

The Current Status of Bioartificial Pancreas Devices

Type 1 diabetes mellitus is a common and highly morbid disease for which there is no cure. Treatment primarily involves exogenous insulin administration, and, under specific circumstances, islet or pancreas transplantation. However, insulin replacement alone fails to replicate the endocrine function of the pancreas and does not provide durable euglycemia. In addition, transplantation requires lifelong use of immunosuppressive medications, which has deleterious side effects, is expensive, and is inappropriate for use in adolescents. A bioartificial pancreas that provides total endocrine pancreatic function without immunosuppression is a potential therapy for treatment of type 1 diabetes. Numerous models are in development and take different approaches to cell source, encapsulation method, and device implantation location. We review current therapies for type 1 diabetes mellitus, the requirements for a bioartificial pancreas, and quantitatively compare device function.

Polyomavirus and cytomegalovirus infections are risk factors for grafts loss in simultaneous pancreas and kidney transplant

BACKGROUND

Published literature on predictors of polyomavirus (BKV) and cytomegalovirus (CMV) infections in simultaneous pancreas and kidney (SPK) transplant and their impact on allograft outcomes remain sparse. We hypothesize that BKV and CMV viremia infections decrease allograft survival in SPK. Identifying modifiable predictors of BKV and CMV may help tailor immunosuppression and improve allograft survival.

METHODS

All SPK recipients at our institution between January 2000 and April 2016 were included (n = 757). Thirty-nine recipients had BKV only and 25 had CMV only, and infection occurred at median follow-up times of 217 and 163 days, respectively. Event density sampling was used to match recipients with BKV or CMV to up to 10 recipients without infection by age, sex, and HLA mismatch status, and these were followed for a median of 4.3 years after infection.

RESULTS

Older age (HR 1.49 for each decade; 95% CI: 0.95, 2.35; P = .083) and tacrolimus use (HR 20.6; 95% CI: 2.37, 179.53; P = .006) were associated with increased incidence of BKV, but not CMV, infection. Both BKV and CMV infections were associated with increased risk of allograft failure for both pancreas (BKV [HR 2.17; 95% CI 1.47, 3.208; P = .000], CMV [HR 1.7; 95% CI 1.077, 2.687; P = .023]) and kidney (BKV [HR 2.65; 95% CI 1.765, 3.984; P = .000], CMV [HR 2.07; 95% CI 1.295, 3.308; P = .002]).

CONCLUSION

Older age at time of transplant and tacrolimus may help predict BKV infection in SPK recipients.

Challenges of pancreas transplantation in developing countries, exploring the Turkey example

Pancreas transplantation significantly improves the quality of life for people with type 1 diabetes, primarily by eliminating the need for insulin and frequent blood glucose measurements. Despite the growing numbers of solid organ transplantations worldwide, number of pancreas transplantations in the developing countries` remain significantly low. This difference of pancreas transplantation practices was striking among the participating countries at the 1st International Transplant Network Meeting which was held in Turkey on 2018. In this meeting more than 40 countries were represented. Most of these counties were developing countries located in Africa, Middle East or Asia. The aim of this article is to identify the challenges and limiting factors for pancreas transplantations in these developing countries, by exploring the Turkish example. The challenges faced by the developing countries are broadly classified in four categories; wait-listing, donor pool, team work and follow up. Under these categorical titles, issues are further discussed in detail, giving examples from Turkish practice of pancreas transplantation. Additionally, several solutions to these challenges have been proposed- some of which have already been undertaken by the Turkish Ministry of Health. With the insight and methods presented in this article, pancreas transplantation should be made possible for the potential recipients in the developing countries.

Cell encapsulation: Overcoming barriers in cell transplantation in diabetes and beyond

Cell-based therapy is emerging as a promising strategy for treating a wide range of human diseases, such as diabetes, blood disorders, acute liver failure, spinal cord injury, and several types of cancer. Pancreatic islets, blood cells, hepatocytes, and stem cells are among the many cell types currently used for this strategy. The encapsulation of these "therapeutic" cells is under intense investigation to not only prevent immune rejection but also provide a controlled and supportive environment so they can function effectively. Some of the advanced encapsulation systems provide active agents to the cells and enable a complete retrieval of the graft in the case of an adverse body reaction. Here, we review various encapsulation strategies developed in academic and industrial settings, including the state-of-the-art technologies in advanced preclinical phases as well as those undergoing clinical trials, and assess their advantages and challenges. We also emphasize the importance of stimulus-responsive encapsulated cell systems that provide a "smart and live" therapeutic delivery to overcome barriers in cell transplantation as well as their use in patients.

The Discovery of Insulin: An Important Milestone in the History of Medicine

The discovery of insulin represents an authentic breakthrough, characterized, at the same time, by contrasts, controversies and disputes among scholars, as well as by great disappointments, failures and hopes. It is the story of famous, almost famous and little known people, of serendipities, discoveries and re-discoveries. The discovery of insulin has been a milestone and has truly revolutionized both the therapy and the prognosis of the diabetes, one of the diseases most studied in the history of medicine, whose first mentions trace back to a collection of ancient Egyptian, Indian and Chinese textbooks. As stated by Colwell, the introduction of insulin has heralded the end of the so-called "pre-insulin era" or "frustration era", paving the way for a new era and clinical advancements. The current review offers a broad, comprehensive overview of main steps culminating into insulin discovery, including recent advancements such as personalized and individualized insulin therapy.

Solid organ transplantation in the 21st century

Solid organ transplantation (SOT) has emerged from an experimental approach in the 20th century to now being an established and practical definitive treatment option for patients with end-organ dysfunction. The evolution of SOT has seen the field progress rapidly over the past few decades with incorporation of a variety of solid organs-liver, kidney, pancreas, heart, and lung-into the donor pool. New advancements in surgical technique have allowed for more efficient and refined multi-organ procurements with minimal complications and decreased ischemic injury events. Additionally, immunosuppression therapy has also seen advancements with the expansion of immunosuppressive protocols to dampen the host immune response and improve short and long-term graft survival. However, the field of SOT faces new barriers, most importantly the expanding demand for SOT that is outpacing the current supply. Allocation protocols have been developed in an attempt to address these concerns. Other avenues for SOT are also being explored to increase the donor pool, including split-liver donor transplants, islet cell implantation for pancreas transplants, and xenotransplantation. The future of SOT is bright with exciting new research being explored to overcome current obstacles.

Tissue-engineering approaches in pancreatic islet transplantation

Pancreatic islet transplantation is a promising alternative to whole-pancreas transplantation as a treatment of type 1 diabetes mellitus. This technique has been extensively developed during the past few years, with the main purpose of minimizing the complications arising from the standard protocols used in organ transplantation. By using a variety of strategies used in tissue engineering and regenerative medicine, pancreatic islets have been successfully introduced in host patients with different outcomes in terms of islet survival and functionality, as well as the desired normoglycemic control. Here, we describe and discuss those strategies to transplant islets together with different scaffolds, in combination with various cell types and diffusible factors, and always with the aim of reducing host immune response and achieving islet survival, regardless of the site of transplantation.

Multi-Modality Imaging Evaluation of the Whole-Organ Pancreas Transplant

Pancreas transplants are an important treatment options for patients with severe diabetes mellitus and other medical conditions. Multiple-imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) are available to evaluate the pancreas transplants and their vascular supply, with the graft having a characteristic appearance on each modality. Complications of the graft and its vascular supply present interesting challenges to the clinicians and radiologists caring for this patient population. Being able to identify the imaging appearance of normal and abnormal pancreas transplants, it is necessary to ensure these patients are provided optimal care.

Does Enteric Conversion Affect Graft Survival After Pancreas Transplantation with Bladder Drainage?

Background

Although bladder drainage is effective for monitoring urine amylase levels to detect graft rejection, enteric drainage is performed more frequently. The optimal method for monitoring pancreatic enzyme secretions remains unclear. We investigated graft survival in recipients of bladder drainage and assessed the risk of graft rejection and failure after enteric conversion.

Material/Methods

From January 1999 to October 2015, we performed 318 pancreas transplantations at our institution. We enrolled 180 recipients who underwent pancreas transplantation with bladder drainage (82 underwent enteric conversion and the rest did not).

Results

The mean interval between pancreas transplantation and enteric conversion was 20±24 months. The graft survival rate was significantly higher in the enteric conversion group for 10 years after pancreas transplantation than in the maintain bladder drainage group. After enteric conversion, 14 recipients lost graft function. The interval between enteric conversion and graft failure was 43±26 months. In the enteric conversion group, immediate postoperative thromboembolectomy (HR=12.729, p=0.000), renal failure (HR=5.710, p=0.005), pancreas graft rejection after EC (HR=19.006, p=0.000), and delayed graft function (HR=7.021, p=0.001) had a significant relationship with graft failure.

Conclusions

Enteric conversion can be safe and effective for improving short- and long-term graft survival if performed after approximately 9 months. Caution should be exercised with enteric conversion if recipients have a history of thromboembolectomy, delayed graft function, or renal failure.

Association between the pancreas transplantation and survival of patients with diabetes: A single center experience

Pancreas transplantation is considered a therapeutic option for patients with complicated diabetes mellitus. In this study, we compared survival rate between patients on the waiting list for pancreas transplant alone(PTA), simultaneous pancreas–kidney(SPK) transplant, and pancreas after kidney(PAK) transplant and transplant recipients. A total of 503 patients (PTA:n = 116; SPK:n = 303; PAK:n = 84) and 280 PT recipients (PTA:n = 89; SPK:n = 155; PAK:n = 36) were retrospectively analyzed at our center between February 2000 and December 2015; 11.9%(60/503) of the patients on the waiting list and 4.3%(12/280) of the PT recipients died. The overall survival rate was higher in the waiting list group for the first year (99.3% vs. 97.8%), after which it was significantly higher in PT group (p = 0.039). The overall relative risk of all-cause mortality for transplant recipients was 2.145(p = 0.285) for PTA, 0.688(p = 0.735) for PAK, however,0.361 (p = 0.012) for SPK compared with that for the waiting list patients. SPK transplant recipients had considerable higher survival benefits, despite the relatively long waiting period, especially after 1 year. In addition, PTA and PAK can also be considered as a treatment option as patient survival was not poor.

Incidence and Indications for Late Allograft Pancreatectomy While on Continued Immunosuppression

BACKGROUND

There are limited data about the incidence and indications for late allograft pancreatectomy while on continued immunosuppression for functional kidney allografts.

METHODS

We analyzed recipients of simultaneous pancreas and kidney and pancreas after kidney transplants between January 1994 and July 2013. Patients with functional kidney but failed pancreas allografts after 90 days were included.

RESULTS

Out of 1022 simultaneous pancreas and kidney or pancreas after kidney recipients, 246 satisfied these criteria. Of these, 50 underwent allograft pancreatectomy (Px) and 196 did not (no-Px). Eleven of these pancreatectomies were performed at the time of repeat transplant and were analyzed separately. None of the basic recipient or donor characteristics differed significantly between the Px (n = 39) and no-Px groups, except for a higher proportion of females in the Px group. The most common presentation in the Px group was abdominal pain. Histopathology of the pancreas varied widely with graft thrombosis as the most common finding. In univariate and multivariate Cox regression analyses, only female recipient was associated with higher risk for allograft pancreatectomy. Px was not associated with kidney allograft survival (P = 0.16).

CONCLUSIONS

Despite the ongoing presence of full immunosuppression for a functioning kidney allograft, the need for Px for symptoms and radiological findings is not rare (39/246, 15.8%).

Long-term Outcomes for Living Pancreas Donors in the Modern Era

BACKGROUND

Living donor segmental pancreas transplants (LDSPTx) have been performed selectively to offer a preemptive transplant option for simultaneous pancreas-kidney recipients and to perform a single operation decreasing the cost of pancreas after kidney transplant. For solitary pancreas transplants, this option historically provided a better immunologic match. Although short-term donor outcomes have been documented, there are no long-term studies.

METHODS

We studied postdonation outcomes in 46 segmental pancreas living donors. Surgical complications, risk factors (RF) for development of diabetes mellitus (DM) and quality of life were studied. A risk stratification model (RSM) for DM was created using predonation and postdonation RFs. Recipient outcomes were analyzed.

RESULTS

Between January 1, 1994 and May 1, 2013, 46 LDSPTx were performed. Intraoperatively, 5 (11%) donors received transfusion. Overall, 9 (20%) donors underwent splenectomy. Postoperative complications included: 6 (13%) peripancreatic fluid collections and 2 (4%) pancreatitis episodes. Postdonation, DM requiring oral hypoglycemics was diagnosed in 7 (15%) donors and insulin-dependent DM in 5 (11%) donors. RSM with three predonation RFs (oral glucose tolerance test, basal insulin, fasting plasma glucose) and 1 postdonation RF, greater than 15% increase in body mass index from preoperative (Δ body mass index >15), predicted 12 (100%) donors that developed postdonation DM. Quality of life was not significantly affected by donation. Mean graft survival was 9.5 (±4.4) years from donors without and 9.6 (±5.4) years from donors with postdonation DM.

CONCLUSIONS

LDSPTx can be performed with good recipient outcomes. The donation is associated with donor morbidity including impaired glucose control. Donor morbidity can be minimized by using RSM and predonation counseling on life style modifications postdonation.

Polymeric Materials for Perm-Selective Coating of Alginate Microbeads

Application of microencapsulation to the immunoisolation of pancreatic islets holds promise for expanding the use of islet transplantation as a treatment option for Type 1 diabetes. It is generally believed that successful development of a reliable methodology will ideally allow for transplantation of pancreatic islets that are protected from the immune system, thereby obviating the need for the use of immunosuppressive drugs and their attendant side effects. In addition, this technology has the potential to expand the donor pool as islets from nonhuman donors could be used as xenografts in human patients. The complex polysaccharide, alginate, has been the most widely used polymer for microencapsulation of islets. However, it is known that alginate lacks appreciable permselectivity to confer immunoisolation of encapsulated islets, thus necessitating the routine permselective coating of alginate microbeads with polymers of amino acids, mainly, poly-L-lysine (PLL) and poly-L-ornithine (PLO). The protocol described in this chapter outlines the steps we have used in our studies on perm-selective coating of alginate microbeads for islet transplantation.

Antibody-Mediated Rejection in Solid Organ Transplant

Within a little more than a decade, the transplant of human organs for end-stage organ disease became a reality. The early barriers to successful long-term graft and patient survival were related to the inability to effectively control the immune system such that it would not attack the donor tissue but would still recognize and destroy invading organisms and cells. As immunosuppressive therapy has been refined and proper matching of donors and recipients has been improved, hyperacute rejection has become a rare occurrence and acute rejection has been markedly controlled. However, antibody-mediated rejection remains an important impediment to increased survival of transplanted organs. This article provides readers with a broad overview of the immune system, discusses mechanisms of transplant rejection, and details prevention, detection, and treatment of antibody-mediated rejection in solid organ transplant.

Pancreas Transplantation From Living Donors: A Single Center Experience of 20 Cases

Living donor pancreas transplantation (LDPT) has several advantages over deceased donor pancreas transplantation (DDPT), including better HLA matching, shorter ischemic time, and shorter waiting time. It remains an attractive option for diabetes mellitus (DM) patients with end stage renal disease. We reviewed 20 cases of LDPT performed in Asan Medical Center between October 1992 and March 2015. Six cases (30%) were pancreas transplantation alone (PTA), and the rest (70%) were simultaneous pancreas and kidney transplantation (SPK). Relations of donor and recipient were parents in 7 (35%), siblings in 6 (30%), spouse in 6 (30%), and cousin in 1 (5%). Graft survival in SPK at 1, 3, 5, and 10 years was 91.7%, 83.3%, 83.3%, and 83.3%, respectively, and that in PTA recipients was 50%, 33.3%, 16.7%, and 16.7%, respectively (p = 0.005). Causes of graft failure in SPK were thrombosis (one case), and rejection (one case), whereas those in PTA were noncompliance (two cases), thrombosis (one case), reflux pancreatitis (one case), and chronic rejection (one case). In terms of pancreas exocrine drainage, two grafts (25%) maintained their function in bladder drainage, while all grafts maintained in enteric drainage p < 0.05). Seven (35%) donors experienced minor pancreatic juice leakage and one underwent reoperation due to postoperative hematoma. Most donors maintained normoglycemia and normal renal function. However, two donors developed DM (at 1 and 90 months postdonation), and were treated with oral hypoglycemic agents. Graft survival in PTA recipients was poorer than in SPK due to poor compliance and bladder drainage-related problems. The surgical and metabolic complication rates of donors can be minimized by applying strict donor criteria. Therefore, LDPT with enteric drainage is an acceptable treatment for SPK.

Stem Cells and Organ Transplantation: Resetting Our Biological Clocks

The human body has only a limited ability to repair itself. Illness, injury, and aging can overwhelm its built-in capability to replace dysfunctional, damaged, or destroyed tissues. We can at best only partly regenerate our organs and cannot grow back a whole limb.

The immunomodulation to diabetes control: New proposals for the reversion of this disease

The diabetes mellitus is a metabolic disorder, characterized by the hyperglycemia with deficiency in the use of carbohydrates, fats and proteins, resultant of the impairment in secretion and/or insulin action. Severely, the type 1 diabetes provokes the compromise of several organs, causing different disorders and until death of patient. In this way, the literature has shown the general treatments for the type 1 diabetes and currently the focus in immunotherapy and/or immunomodulation, to control of this hyperglycemic condition. The use of new therapies is necessary due to the high increase of incidence of this disease around the world. Recent studies showed an increase of 40% in the cases since 1997. This disease affects different organs, including the glandular tissues, mainly the pancreas. Despite all therapies for diabetes control, the damages occurred remain irreversible. Thus, in addition to general treatments, the use of immunotherapy may open new perspectives for treatment of this disease. Within this aspect, the anti-CD3 monoclonal antibodies may be effective, mainly by protect and maintain the pancreatic acinar cells. Thus, these treatments based in the immunomodulation can be an option for diabetes control and to reverse the damage caused by this disease.

Bioengineered stem cells as an alternative for islet cell transplantation

Type 1 diabetes is an autoimmune and increasingly prevalent condition caused by immunological destruction of beta cells. Insulin remains the mainstay of therapy. Endeavours in islet transplantation have clearly demonstrated that type 1 diabetes is treatable by cellular replacement. Many challenges remain with this approach. The opportunity to use bioengineered embryonic or adult pluripotential stem cells, or islets derived from porcine xenograft sources could address future demands, but are still associated with considerable challenges. This detailed review outlines current progress in clinical islet transplantation, and places this in perspective for the remarkable scientific advances now occurring in stem cell and regenerative medicine approaches in the treatment of future curative treatment of diabetes.

Morphological characteristics and identification of islet-like cells derived from rat adipose-derived stem cells cocultured with pancreas adult stem cells

Diabetes is a significant public health problem that can be treated with insulin therapy; however, therapies designed to cure diabetes are limited. The goal of the current study was to assess the potential for curative treatment of diabetes using adipose-derived stem cells (ADSCs). To achieve this goal, the differentiation of rat ADSCs into pancreatic islet-like cells induced by coculture with pancreatic adult stem cells (PASCs) was characterized. Differentiation of ADSCs into islet-like cells induced by coculturing was determined morphologically, as well as by the assessment of islet cell markers using dithizone staining, immunohistochemistry, RT-PCR, qPCR, and western blotting. The results showed that ADSCs formed islet-like round cell masses after coculture with PASCs. These differentiated cells were shown to be positive for islet cell markers, including dithizone incorporation; PDX1, CK19 and Nestin by immunohistochemistry, and insulin, PDX1 and glucagon expression by RT-PCR. Differentiated ADSCs induced by coculturing also expressed insulin at the mRNA and protein level, with the level of insulin mRNA expression in cocultured ADSCs being 0.05 times greater than that of PASCs (P < 0.05). Taken together, our results demonstrate that ADSCs can be induced to differentiate into islet-like cells by coculture with PASCs; thus these cells can be used for transplantation, providing a theoretical foundation for the treatment of diabetes using this approach.

Pancreas transplantation: a treatment option for people with diabetes

Since the first pancreas transplants in the early 1960s, whole-organ pancreas transplantation, either alone or combined with kidney transplantation, has become commonplace in many countries around the world. Whole-organ pancreas transplantation is available in the UK, with ~200 transplants currently carried out per year. Patient survival and pancreas graft outcome rates are now similar to other solid organ transplant programmes, with high rates of long-term insulin independence. In the present review, we will discuss whole-pancreas transplantation as a treatment for diabetes, focusing on indications for transplantation, the nature of the procedure performed, graft survival rates and the consequences of pancreas transplantation on metabolic variables and the progression of diabetes-related complications.

Current status of clinical islet transplantation

Islet transplantation (IT) is today a well-established treatment modality for selected patients with type 1 diabetes mellitus (T1DM). After the success of the University of Alberta group with a modified approach to the immune protection of islets, the international experience grew along with the numbers of transplants in highly specialized centers. Yet, long-term analysis of those initial results from the Edmonton group indicated that insulin-independence was not durable and most patients return to modest amounts of insulin around the fifth year, without recurrent hypoglycemia events. Many phenomena have been identified as limiting factor for the islet engraftment and survival, and today all efforts are aimed to improve the quality of islets and their engrafting process, as well as more optimized immunosuppression to facilitate tolerance and ultimately, better long term survival. This brief overview presents recent progress in IT. A concise historical perspective is provided, along with the latest efforts to improve islet engraftment, immune protection and ultimately, prolonged graft survival. It is apparent that as the community continues to work together further optimizing IT, it is hopeful a cure for T1DM will soon be achievable.

Trends in immunosuppression after pancreas transplantation: what is in the pipeline?

PURPOSE OF REVIEW

To provide an overview of currently available immunosuppressive strategies and novel therapeutic developments in pancreas transplantation.

RECENT FINDINGS

From 1966 through 2012 more than 30 000 pancreas transplantations have been performed around the world with excellent patient and graft survival. However, drug-related side effects and toxicities remain to negatively affect long-term outcomes. At present, more than 90% of pancreas transplant recipients receive induction therapy with depleting or nondepleting antibodies. The most widely used maintenance protocols are based on tacrolimus and mycophenolate mofetil with early or delayed corticosteroid withdrawal. In case of documented side effects related to this standard protocol, several regimens are actively pursued to switch to mammalian target of rapamycin inhibitors as well as to attempt initial calcineurin inhibitor avoidance and immunosuppression minimization. In addition, the recent documented negative impact of donor-specific antibodies on pancreas transplantation outcome has resulted in new treatment protocols for antibody-mediated rejection including intravenous immunoglobulins, anti-CD20 antibodies and protease inhibitors.

SUMMARY

Implementation of novel therapeutic strategies and combination protocols to reduce or avoid drug toxicities and immune-related complications that are evaluated in prospective and randomized trials is requested to improve outcomes after pancreas transplantation.

Evolution of pancreas transplantation: long-term results and perspectives from a high-volume center

OBJECTIVE

To describe the evolution of pancreas transplantation from 1979 to 2011. The aim was to examine factors influencing long-term patient and graft survival, surgical methods, and risk factors influencing organ performance after transplantation.

BACKGROUND

Pancreas transplantation has become the therapy of choice for patients suffering insulin-dependent diabetes and end stage renal failure.

METHODS

Retrospective analysis of 509 consecutive pancreas transplants (442 simultaneous pancreas and kidney [SPK], 20 pancreas transplanted alone [PTA], and 47 pancreas transplanted after kidney [PAK]), performed at the University Hospital Innsbruck. The data were statistically analyzed using the Kaplan-Meier method and log-rank test.

RESULTS

After overcoming initial immunological and technical problems between 1979 and 1988 (5-year pancreas graft survival rate, 29.7%), pancreas transplantation evolved during the second decade (1989-1996; 5-year pancreas graft survival rate, 42.2%). Technical changes, optimized immunosuppression, careful pretransplant evaluation, and improved graft monitoring have become standard in the last decade and result in excellent 5-year patient (94.3%), kidney (89.4%), and pancreas (81.5%) graft survival. Five-year graft survival was superior in SPK (68.8%) compared with PAK (62.5%) and PTA (16.4%). SPK retransplantation can be carried out safely with 5-year patient (87.5%) and pancreas graft (75.0%) survival. Overall 5-year patient survival after loss of the first pancreas graft is significantly better in patients who underwent retransplantation (89.4% vs. 67.9%, P = 0.001). Long-term pancreas graft survival is independent of donor body mass index, sex, and cause of death, anastomosis time and the number of human leukocyte antigen (HLA) mismatches, recipient age, body mass index, sex, current panel reactive antibodies, and waiting time. Significant risk factors for reduced graft survival are cold ischemia time and donor age.

CONCLUSIONS

During the last 32 years, many problems in pancreas transplantation have been overcome and it may currently represent the therapeutic gold standard for some patients with diabetes and end stage renal failure.

Prevention and management of graft thrombosis in pancreatic transplant

Pancreatic transplant effectively cures type 1 diabetes mellitus and maintains consistent long-term euglycemia. However, technical failure, and in particular graft thrombosis, accounts for the vast majority of transplants lost in the early postoperative period. The pancreas' inherently low microvascular flow state makes it vulnerable to vascular complications, as does the hypercoagulable blood of diabetic patients. Ultimately, the phenomenon is most definitely multifactorial. Prevention, as opposed to treatment, is key and should focus on reducing these multiple risk factors. This will involve tactical donor selection, optimal surgical technique and some form of anticoagulation. Close monitoring and early intervention will be crucial when treating thrombosis once preventative methods have failed. This may be achieved by further anticoagulation, graft salvage, or pancreatectomy with retransplant. This article will explore the multiple factors contributing to graft thrombus formation and the ways in which they may be addressed to firstly prevent, or more likely, reduce thrombosis. Secondly, we will consider the management strategies which can be implemented once thrombosis has occurred.

Transplantation of the pancreas

Pancreas transplantation consistently induces insulin-independence in beta-cell-penic diabetic patients, but at the cost of major surgery and life-long immunosuppression. One year after grafting, patient survival rate now exceeds 95 % across recipient categories, while insulin independence is maintained in some 85 % of simultaneous pancreas and kidney recipients and in nearly 80 % of solitary pancreas transplant recipients. The half-life of the pancreas graft currently averages 16.7 years, being the longest among extrarenal grafts, and substantially matching the one of renal grafts from deceased donors. The difference between expected (100 %) and actual insulin-independence rate is mostly explained by technical failure in the postoperative phase, and rejection in the long-term period. Death with a functioning graft remains a further major issue, especially in uremic patients who have undergone prolonged periods of dialysis. Refinements in graft preservation, surgical techniques, immunosuppression, and prophylactic treatments are expected to further improve the results of pancreas transplantation.

In vitro generation of functional insulin-producing cells from human bone marrow-derived stem cells, but long-term culture running risk of malignant transformation

Efforts involving therapeutic islet cell transplantation have been hampered by limited islet availability and immune rejection. In vitro transdifferentiation of human bone marrow-derived stem (hBMDS) cells into functional insulin-producing cells promises to provide a tissue source for autologous cell transplantation. In this study, we isolated hBMDS cells, developed a single-cell-derived stem cell line, and induced the cells to differentiate into islet-like clusters. These islet-like cells expressed multiple genes related to islet development and beta cell function (e.g., Pdx-1, Ngn-3, Islet-1, Neuro-D, Pax4, IAPP, and insulin) and produced insulin and C-peptide within these cells. These islet-like cells demonstrated time-dependent glucose-stimulated insulin release, and the ability to ameliorate hyperglycemia in chemically induced diabetic mice. However, these transplanted differentiated cells became tumorigenic in diabetic immunocompromised mice and their spontaneous transformation was confirmed by a marked increase in growth rate and inactivation of tumor suppressor genes (P21 and P16) by promoter hypermethylation. In conclusion, while hBMDS cells can be transdifferentiated into competent insulin-producing cells, and while such cell might be a potential source for autologous cell therapy for type 1 diabetes, caution is strongly advised in view of the neoplastic propensity of hBMDS cells, especially after a long-term culture in vitro.

Reprogramming of bone marrow-derived mesenchymal stem cells into functional insulin-producing cells by chemical regimen

Beta-cell transplantation is considered to be the most effective approach to cure type 1 diabetes (T1D). Unfortunately, the scarce availability of donor tissue limits the applicability of this therapy. Recent stem cell research progress shows stem cell therapy may be a potential means to solve this problem. Bone marrow-derived mesenchymal stem cells (MSCs) are self-renewable and multipotent adult stem cells which can differentiate into the three germ layers. Here we aimed to investigate whether MSCs could be reprogrammed into insulin-producing cells (IPCs). We isolated and characterized MSCs obtained from rat bone marrow. Then MSCs were induced to transdifferentiate into IPCs under specific conditions containing high concentrations of glucose, activin A, all-trans retinoic acid, and other maturation factors. The induced cells expressed multiple genes related to pancreatic beta-cell development and function, such as insulin1, glucagon, Pdx1, Pax6, and Glut-2. Insulin1 and C-peptide production were identified by immunocytochemistry. In vitro glucose challenge studies showed the induced cells secreted insulin in a glucose-dependent manner, as do normal pancreatic beta-cells. Transplantation of these MSC-derived insulin-positive cells could reverse the hyperglycemia of streptozotcin (STZ)-induced diabetic rats. These results demonstrated that MSCs could be reprogrammed into IPCs and might be a potential autologous cell source for transplantation therapy of T1D.