Type 1 diabetes(T1D)is a chronic,lifelong,autoimmune disease that is debilitating and life-threatening to those who suffer from severe hypoglycaemic events or the devastating chronic complications.Exogenous insulin re...Type 1 diabetes(T1D)is a chronic,lifelong,autoimmune disease that is debilitating and life-threatening to those who suffer from severe hypoglycaemic events or the devastating chronic complications.Exogenous insulin replacement,including the artificial pancreas,is the current mainstay of T1D therapy but cannot prevent the chronic vascular complications of the disease.They are also responsible for contributing to severe iatrogenic hypoglycaemia and impaired hypoglycaemic awareness.β-cell replacement with either pancreas or islet allotransplantation can reverse diabetes leading to better glycaemic control,prevention of hypoglycaemic events and improved quality of life for patients.The limited supply of cadaveric organ donors is a major barrier to this therapeutic option.Thus,alternative sources of islets are being actively explored,mainly human pluripotent stem-cell derived islets and xenogeneic porcine islets.Although these sources harbor their own risks and problems,various novel and innovative solutions are being perseveringly investigated across the globe to overcome these in the hopes that safe islet transplantation may one day be available to all T1D patients suffering from severe hypoglycaemic events.This review will concentrate on pre-clinical and clinical studies,in addition to the latest scientific discoveries relevant to T1D transplantation therapy using allogeneic or xenogeneic donor islet cells.展开更多
Dear Editor,Type 1 diabetes(T1D)is a complex autoimmune disease characterized by the progressive destruction of pancreaticβ-cells,leading to insulin deficiency.Despite extensive research,the specific triggering facto...Dear Editor,Type 1 diabetes(T1D)is a complex autoimmune disease characterized by the progressive destruction of pancreaticβ-cells,leading to insulin deficiency.Despite extensive research,the specific triggering factors that initiate and advance T1D remain elusive.Over recent decades,we have observed a concerning global increase in T1D incidence,notable not only for its rising numbers,but also for a concerning trend towards younger age at diagnosis.Transplantation of pancreatic islets to the portal system of the liver is used as a treatment strategy for T1D.However,the success rate has been limited due to poor graft survival,despite immunosuppressive treatment,and often multiple transplantations are needed to obtain adequate secretion of insulin.1 Hence,for islet transplantation to become a viable treatment option for T1D,it is essential to both identify a more suitable transplantation site and develop methods to engineer islets that are resistant to inflammatory and immunological attacks.展开更多
BACKGROUND Not all islet transplants desirably achieve insulin independence.This can be attributed to the microarchitecture and function of the islets influenced by their dimensions.Large islets enhance insulin secret...BACKGROUND Not all islet transplants desirably achieve insulin independence.This can be attributed to the microarchitecture and function of the islets influenced by their dimensions.Large islets enhance insulin secretion through paracrine effects but are more susceptible to hypoxic injury post-transplant,while small islets offer better viability and insulin independence.In vivo studies suggest large islets are essential for maintaining euglycemia,though smaller islets are typically preferred in transplantation for better outcomes.AIM To document the impact of islet dimension on clinical and preclinical transplant outcomes to optimize procedures.METHODS PubMed,Scopus and EMBASE platforms were searched for relevant literature up to 9 April 2024.Articles reported on either glucose-stimulated insulin-secreting(GSIS)capacity,islet viability and engraftment,or insulin independence based on the islet dimension were included.The risk of bias was measured using the Appraisal Tool for Cross-Sectional Studies.Extracted data was analyzed via a narrative synthesis.RESULTS Nineteen studies were included in the review.A total of sixteen studies reported the GSIS,of which nine documented the increased insulin secretion in the small islet,where the majority reported insulin secretion per islet equivalent(IEQ).Seven studies documented increased GSIS in large-sized islets that measure insulin secretion per cell or islet.All the articles that compared small and large islets reported poor viability and engraftment of large islets.CONCLUSION Small islets with a diameter<125μm have desired transplantation outcomes due to their better survival following isolation.Large-sized islets receive blood supply directly from arterioles in vivo to meet their higher metabolic demands.The large islet undergoes central necrosis soon after the isolation(devascularization);failing to maintain the viability and glucose stimuli leads to a decline in GSIS and the overall function of the islet.Improved preservation of large islets after islet isolation,enhances the islet yield(IEQ),thereby reducing the likelihood of failed islet isolation and potentially improves transplant outcome.展开更多
AIM: To develop an experimental model of islet allotransplantation in diabetic rats and to determine the positive or adverse effects of MMF as a single agent. METHODS: Thirty-six male Wistar rats and 18 male Lewis rat...AIM: To develop an experimental model of islet allotransplantation in diabetic rats and to determine the positive or adverse effects of MMF as a single agent. METHODS: Thirty-six male Wistar rats and 18 male Lewis rats were used as recipients and donors respectively. Diabetes was induced by the use of streptozotocin (60 mg/kg) intraperitoneally. Unpurified islets were isolated using the collagenase digestion technique and transplanted into the splenic parenchyma. The recipients were randomly assigned to one of the following three groups: group A (control group) had no immunosuppression; group B received cyclosporine (CsA) (5 mg/kg); group C receivedmycophenolate mofetil (MMF) (20 mg/kg). The animalswere killed on the 12th d. Blood and grafted tissues were obtained for laboratory and histological assessment. RESULTS: Median allograft survival was significantly higher in the two therapy groups than that in the controls (10 and 12 d for CsA and MMF respectively vs 0 d for the control group, P＜0.01). No difference in allograft survival between the CsA and MMF groups was found. However,MMF had less renal and hepatic toxicity and allowed weight gain.CONCLUSION: Monotherapy with MMF for immunosu ppression was safe in an experimental model of islet allotransplantation and was equally effective with cyclosporine, with less toxicity.展开更多
AIM: To determine whether the elevated vascular endothelial growth factor (VEGF) expression produced by the transfected vascular endothelial cells (VECs) could stimulate angiogenesis of the graft islets and exert its ...AIM: To determine whether the elevated vascular endothelial growth factor (VEGF) expression produced by the transfected vascular endothelial cells (VECs) could stimulate angiogenesis of the graft islets and exert its effect on the graft function. METHODS: Thirty diabetic recipient rats were divided into three groups (n = 10 per group). In the control group,300 IEQ islets were transplanted in each rat under the capsule of the right kidney,which were considered as marginal grafts. In the VEC group,VEC together with the islets were transplanted in each rat. In the VEGF group,VEC transfected by pIRES2-EGFP/ VEGF165 plasmid and the islets were transplanted in each rat. Blood glucose and insulin levels were evaluated every other day after operation. Intravenous glucose tolerance test (IVGTT) was performed 10 d after the transplantation. Hematoxylin and eosin (HE) staining was used to evaluate the histological features of the graft islets. Immunohistochemical staining was used to detect insulin-6,VEGF and CD34 (MVD) expression in the graft islets. RESULTS: Blood glucose and insulin levels in the VEGF group restored to normal 3 d after transplantation. In contrast,diabetic rats receiving the same islets with or without normal VECs displayed moderate hyperglycemia and insulin,without a significant difference between these two groups. IVGTT showed that both the amplitude of blood glucose induction and the kinetics of blood glucose in the VEGF group restored to normal after transplantation. H&E and immunohistochemical staining showed the presence of a large amount of graft islets under the capsule of the kidney,which were positively stained with insulin-6 and VEGF antibodies in the VEGF group. In the cell masses,CD34-stained VECs were observed. The similar masses were also seen in the other two groups,but with a fewer positive cells stained with insulin-6 and CD34 antibodies. No VEGF-positive cells appeared in these groups. Microvessel density (MVD) was significantly higher in the VEGF group compared to the other two groups. CONCLUSION: Elevated VEGF production by trans-fected vascular endothelial cells in the site of islet transplantation stimulates angiogenesis of the islet grafts. The accelerated islet revascularization in early stage could improve the outcome of islet transplantation,and enhance the graft survival.展开更多
AIM: To evaluate the safety and feasibility of laparoscopic spleen-preserving distal pancreatectomy (LSPDP) with autologous islet transplantation (AIT) for benign tumors of the pancreatic body-neck.
Transplantation of pancreatic tissue, as either the intact whole pancreas or isolated pancreatic islets has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependant diabetes...Transplantation of pancreatic tissue, as either the intact whole pancreas or isolated pancreatic islets has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependant diabetes mellitus. A successful whole pancreas or islet transplant offers the advantages of attaining normal or near normal blood glucose control and normal hemoglobin Alc levels without the risks of severe hypoglycemia associate with intensive insulin therapy. Both forms of transplants are also effective at eliminating the occurrence of significant hypoglycemic events （even with only partial islet function evident）. Whereas whole pancreas transplantation has also been shown to be very effective at maintaining a euglycemic state over a sustained period of time, thus providing an opportunity for a recipient to benefit from improvement of their blood glucose control, it is associated with a significant risk of surgical and post-operative complications. Islet transplantation is attractive as a less invasive alternative to whole pancreas transplant and offers the future promise of immunosuppression-free transplantation through pretransplant culture. Islet transplantation however, may not always achieve the sustained level of tight glucose control necessary for reducing the risk of secondary diabetic complications and exposes the patient to the adverse effects of immunosuppression. Although recent advances have led to an increased rate of obtaining insulin-independence following islet transplantation, further developments are needed to improve the longterm viability and function of the graft to maintain improved glucose control over time.展开更多
AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule wi...AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule with the following: (1) 200 islets (islet group: n=12), (2) 1-5×106 bone marrow cells (bone marrow group: n=11), (3) 200 islets and 1-5×106 bone marrow cells (islet + bone marrow group: n= 13), or (4) no cells (sham group:n=5). All mice were evaluated for blood glucose, serum insulin, serum nervegrowth factor (NGF) and glucose tolerance (GTT) up to postoperative day (POD) 14. Histological assessment for insulin, von Willebrand factor (vWF) and NGF was performed at POD 3, 7 and 14.RESULTS: Blood glucose level was lowest and serum insulin was highest in the islet + bone marrow group. Serum NGF increased in islet, bone marrow, and islet + bone marrow groups after transplantation, and there was a significant difference (P=0.0496, ANOVA) between the bone marrow and sham groups. The number of vessels within the graft area was signif icantly increased in both the bone marrow and islet + bone marrow groups at POD 14 as compared to the islet alone group (21.2 ± 3.6 in bone marrow, P=0.01, vs islet group, 22.6 ± 1.9 in islet + bone marrow, P = 0.0003, vs islet group, 5.3 ± 1.6 in islet-alone transplants). NGF was more strongly expressed in bone marrow cells compared with islets. CONCLUSION: Bone marrow cells produce NGF and promote angiogenesis. Islet co-transplantation with bone marrow is associated with improvement of islet graft function.展开更多
The purpose of the present study was to organize the parameters involved in experimental allotransplantation in rodents to elaborate the most suitable model to supply the scarcity of islet donors. We used the PubMed d...The purpose of the present study was to organize the parameters involved in experimental allotransplantation in rodents to elaborate the most suitable model to supply the scarcity of islet donors. We used the PubMed database to systematically search for published articles containing the keywords “rodent islet transplantation” to review. We included studies that involved allotransplantation experiments with rodents’ islets, and we reviewed the reference lists from the eligible publications that were retrieved. We excluded articles related to isotransplantation, autotransplantation and xenotransplantation, i.e., transplantation in other species. A total of 25 studies related to allotransplantation were selected for systematic review based on their relevance and updated data. Allotransplantation in rodents is promising and continues to develop. Survival rates of allografts have increased with the discovery of new immunosuppressive drugs and the use of different graft sites. These successes suggest that islet transplantation is a promising method to overcome the scarcity of islet donors and advance the treatment options for type 1 diabetes.展开更多
Pancreatic islet transplantation is a minimally invasive procedure aiming to reverse the effects of insulin deficiency in patients with type 1 diabetes(T1D)by transplanting pancreatic beta cells.Overall,pancreatic isl...Pancreatic islet transplantation is a minimally invasive procedure aiming to reverse the effects of insulin deficiency in patients with type 1 diabetes(T1D)by transplanting pancreatic beta cells.Overall,pancreatic islet transplantation has improved to a great extent,and cellular replacement will likely become the mainstay treatment.We review pancreatic islet transplantation as a treatment for T1D and the immunological challenges faced.Published data demonstrated that the time for islet cell transfusion varied between 2 and 10 h.Approximately 54%of the patients gained insulin independence at the end of the first year,while only 20%remained insulin-free at the end of the second year.Eventually,most transplanted patients return to using some form of exogenous insulin within a few years after the transplantation,which imposed the need to improve immunological factors before transplantation.We also discuss the immunosuppressive regimens,apoptotic donor lymphocytes,anti-TIM-1 antibodies,mixed chimerism-based tolerance induction,induction of antigen-specific tolerance utilizing ethylene carbodiimide-fixed splenocytes,pretransplant infusions of donor apoptotic cells,B cell depletion,preconditioning of isolated islets,inducing local immunotolerance,cell encapsulation and immunoisolation,using of biomaterials,immunomodulatory cells,etc.展开更多
BACKGROUND: The most common complication after allogenic islet transplantation is rejection. This study was to evaluate the effect of anti-rejection of glucocorticoid-free immunosuppressive regimen on allogenic islet ...BACKGROUND: The most common complication after allogenic islet transplantation is rejection. This study was to evaluate the effect of anti-rejection of glucocorticoid-free immunosuppressive regimen on allogenic islet transplantation. METHODS: Tacrolimus(FK506)+mycophenolate mofetil (MMF) and FK506+MMF+prednisone (Pred) were administered respectively for 2 weeks to inhibit rejection after allogenic islet transplantation in rats, which were compared with the control group. The concentrations of blood glucose, insulin and C-peptide were determined dynamically in recipients and the sites of transplantation were observed morphologically. RESULTS: As compared with the control group without immunosuppressive agents, FK506+MMF and FK506+MMF+Pred could prolong the survival time of grafts significantly. There were many morphologically intact islets in the liver of recipients 2 months after transplantation. Group FK506+MMF kept normal levels of blood glucose, insulin and C-peptide beyond 60 days after transplantation. In contrast, group FK506+MMF+Pred secreted less C-peptide(P<0.05) and maintained a higher level of blood glucose concentration (P<0.01) after the operation. There was no significant difference in insulin concentrations between the two groups. The level of blood glucose beyond the first 2 weeks after drug withdrawal in group FK506+MMF+Pred decreased obviously (P<0.05), and the secretion of insulin and C-peptide increased. These results were compared with those the first 2 weeks after transplantation and the first 2 weeks after drug withdrawal. CONCLUSIONS: Both regimens of FK506+MMF and FK506+MMF+Pred could provide effective immunosup-pression. Moreover the combined glucocorticoid-free immunosuppressive strategy of low-dose FK506 and MMF could protect islet grafts in islet transplantation without diabetogenic side-effects.展开更多
BACKGROUND: Islet transplantation is considered a po- tentially curative treatment for diabetic mellitus. The aim of this study was to assess the feasibility of islet transplant through the spleen. METHODS: Both donor...BACKGROUND: Islet transplantation is considered a po- tentially curative treatment for diabetic mellitus. The aim of this study was to assess the feasibility of islet transplant through the spleen. METHODS: Both donor and recipient Wistar rats (BW150± 20 g) were provided by the Animal Center of China Medi- cal University, Shenyang, China. Islets were isolated and purified with the modified Minnesota program. 600-800IE graft islets were handpicked and transplanted through the spleen of diabetic recipients. Blood glucose and insulin were evaluated after operation every other day. IVGTT was performed 10 days after transplantation. RESULTS: 300-400IE islet was procured from one donor rat. Secretion index (SI) of the glucose stress was 5.59± 0.62, showing the graft functioning well. The diabetic rats restored normal blood glucose levels of 3.4-5.4 mmol/L (mean 4.8 mmol/L). Their insulin levels were as normal as 8.5-12.2 μIU/ml. The K value of IVGTT in the rats after transplantation was similar to the normal one. CONCLUSIONS: The islets can be transplanted successfully through the spleen, while avoiding the complications caused by traditional transplantation through the portal vein, such as bleeding and portal vein hypertension. The graft islets loss can be reduced because of less centrifugation and mechanic pressure. In conclusion, transplantation through the spleen is a simple and feasible method.展开更多
The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW)....The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging the preservation time. In a canine model, the TLM was shown to repair and resuscitate warm ischemically damaged pancreata during preservation, improve pancreas graft survival after transplantation, and also improve the islet yield after isolation. Clinical trials using the TLM in pancreas preservation before whole-pancreas transplantation and islet isolation have shown promising outcomes. We describe the role of the TLM in pancreas and islet transplantation.展开更多
AIM: To evaluate pain control in chronic pancreatitis patients who underwent total pancreatectomy with islet cell transplantation or intrathecal narcotic pump infusion.METHODS: We recognized 13 patients who underwent ...AIM: To evaluate pain control in chronic pancreatitis patients who underwent total pancreatectomy with islet cell transplantation or intrathecal narcotic pump infusion.METHODS: We recognized 13 patients who underwent intrathecal narcotic pump(ITNP) infusion and 57 patients who underwent total pancreatectomy with autologous islet cell transplantation(TP + ICT) for chronic pancreatitis(CP) pain control between 1998 and 2008 at Indiana University Hospital. All patients had already failed multiple other modalities for pain control and the decision to proceed with either intervention was made at the discretion of the patients and their treating physicians. All patients were evaluated retrospectively using a questionnaire inquiring about their pain control(using a 0-10 pain scale), daily narcotic dose usage, and hospital admission days for pain control before each intervention and during their last follow-up. RESULTS: All 13 ITNP patients and 30 available TP + ICT patients were evaluated. The mean age was approximately 40 years in both groups. The median duration of pain before intervention was 6 years and 7 years in the ITNP and TP + ICT groups, respectively. The median pain score dropped from 8 to 2.5(on a scale of 0-10) in both groups on their last follow up. The median daily dose of narcotics also decreased from 393 mg equivalent of morphine sulfate to 8 mg in the ITNP group and from 300 mg to 40 mg in the TP + ICT group. No patient had diabetes mellitus(DM) before either procedure whereas 85% of those who underwent pancreatectomy were insulin dependent on their last evaluation despite ICT. CONCLUSION: ITNP and TP + ICT are comparable for pain control in patients with CP however with high incidence of DM among those who underwent TP + ICT. Prospective comparative studies and longer follow up are needed to better define treatment outcomes.展开更多
Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabe...Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabetes.The countries where islet transplantation has not been explored suffer from insufficient knowledge concerning key elements of the isolation process.Donor and organ procurement parameters impact human islet yield,although for research purposes,islet yield may be secondary in importance to islet function.This paper will analyze the feasibility of research-only human islet isolation and signify parameters underlying a successful yield in the Indian population.This eventually can make islet transplantation a clinical reality in India.Method:After receiving the consent for procuring brain-dead pancreas from the first-degree of relatives,samples were collected and transported in a transportation buffer at 4℃.The procedure consists of a mechanically enhanced enzymatic digestion of the pancreas,after which it was taken for purification using Ficoll method,followed by islet quality testing.Results:Through 15 isolations done over a span of approximately 2 years during the COVID pandemic in India,we confirm that ischemic time and glycated hemoglobin,each have a negative impact on isolation purity and yield.Notably,extending cold ischemic tim beyond the typical clinical isolation cutoff of 12 hours(to≥18 h)had a huge impact on islet function and yield.Age had a negative correlation with islet yield;however other biological parameters(specifically body mass index)and isolation variables appear to make a significant contribution to the heterogeneity of human islet yield.Our current work demonstrates the feasibility of extending acceptable cold ischemic time for research-focused human islet isolation and highlights the biological variation in isolation of human islets from donors with and without diabetes.Conclusion:India requires establishment of an islet transplant program using the current standard methods of“islet isolation”and donor program and process.Research should focus on improving standards in the islet preparation process to increase the number of successful preparations,shorten the isolation time,and increase patient safety so that the theoretical risk involved can become a practical reality.展开更多
Diabetes is a heterogeneous metabolic disease characterized by elevated blood glucose levels resulting from the destruction or malfunction of pancreaticβcells,insulin resistance in peripheral tissues,or both,and resu...Diabetes is a heterogeneous metabolic disease characterized by elevated blood glucose levels resulting from the destruction or malfunction of pancreaticβcells,insulin resistance in peripheral tissues,or both,and results in a non-sufficient production of insulin.To adjust blood glucose levels,diabetic patients need exogenous insulin administration together with medical nutrition therapy and physical activity.With the aim of improving insulin availability in diabetic patients as well as ameliorating diabetes comorbidities,different strategies have been investigated.The first approaches included enhancing endogenousβcell activity or transplanting new islets.The protocol for this kind of intervention has recently been optimized,leading to standardized procedures.It is indicated for diabetic patients with severe hypoglycemia,complicated by impaired hypoglycemia awareness or exacerbated glycemic lability.Transplantation has been associated with improvement in all comorbidities associated with diabetes,quality of life,and survival.However,different trials are ongoing to further improve the beneficial effects of transplantation.Furthermore,to overcome some limitations associated with the availability of islets/pancreas,alternative therapeutic strategies are under evaluation,such as the use of mesenchymal stem cells(MSCs)or induced pluripotent stem cells for transplantation.The cotransplantation of MSCs with islets has been successful,thus providing protection against proinflammatory cytokines and hypoxia through different mechanisms,including exosome release.The use of induced pluripotent stem cells is recent and requires further investigation.The advantages of MSC implantation have also included the improvement of diabetes-related comorbidities,such as wound healing.Despite the number of advantages of the direct injection of MSCs,new strategies involving biomaterials and scaffolds have been developed to improve the efficacy of mesenchymal cell delivery with promising results.In conclusion,this paper offered an overview of new alternative strategies for diabetes management while highlighting some limitations that will need to be overcome by future approaches.展开更多
I have read with great interest the paper by Pollard et al.(1)published in Hepatobiliary Surgery and Nutrition.This is a retrospective single-center study presenting 10-year follow-up of 60 patients undergoing total p...I have read with great interest the paper by Pollard et al.(1)published in Hepatobiliary Surgery and Nutrition.This is a retrospective single-center study presenting 10-year follow-up of 60 patients undergoing total pancreatectomy with autologous islet transplantation(TPAIT)in the University Hospital of Leicester,one of the most experienced in TPAIT centers in the world.The patients had undergone TPAIT between September 1994 to May 2011(1).The completed 10-year assessment was achieved in 17 patients who were grouped by the authors using the modified Auto-Igls criteria;good response,n=5(insulin-independent for first 5 years post-TPAIT);partial response,n=6(insulin requirements<20 IU/day post-TPAIT)and poor response,n=6(insulin requirements≥20 IU/day post-TPAIT).展开更多
Current research on islet transplantation is aimed at prolonging the survival time and enhancing the functionality of the transplantation system.Owing to the good biocompatibility of hydrogels and their ability to pro...Current research on islet transplantation is aimed at prolonging the survival time and enhancing the functionality of the transplantation system.Owing to the good biocompatibility of hydrogels and their ability to provide mechanical support and immunological isolation of islet cells,hydrogel encapsulation of islets offers an innovative solution for islet transplantation.In this work,inspired by the extracellular matrix structure of the pancreatic islets,an injectable self-healing hydrogel loaded with islet-integrated microfiber scaffolds was constructed for islet transplantation.The short microfiber was fabricated by introducing a gaseous phase into microfluidic spinning,causing the continuous microfibers to break into short segments due to bubble rupture.These short microfibers provide mechanical support for pancreatic islets and can be integrated into a self-healing matrix to form a vascularized hydrogel through Schiff base bonding of oxidized sodium alginate aldehyde groups with carboxymethyl chitosan amino groups.With the loading of human umbilical vein endothelial cells and vascular endothelial growth factor,this composite is both injectable and provides mechanical support for the grafts,extends islet survival time,and improves islet function.In vivo experiments further confirm that this bioinspired composite system minimizes implantation-associated trauma while promoting neovascularization at the graft site in diabetic rodents,thereby achieving prolonged glycemic control compared to non-vascularized systems.These findings demonstrate that this hierarchically structured multifunctional graft platform has substantial research value and extensive therapeutic potential in the fields of cell therapy and tissue engineering for the treatment of diabetes and related diseases.展开更多
BACKGROUND: Triptolide (TPT) is a diterpenoid triepoxide extracted from the Chinese herb Tripterygium wilfordii Hook. F. It exhibits potent immunosuppressive and anti-inflammatory properties. This study was undertaken...BACKGROUND: Triptolide (TPT) is a diterpenoid triepoxide extracted from the Chinese herb Tripterygium wilfordii Hook. F. It exhibits potent immunosuppressive and anti-inflammatory properties. This study was undertaken to investigate its effects on prolongation of islet allograft survival in rodents. Additionally, we investigated whether TPT would be toxic to islet function in vivo. METHODS: We transplanted BALB/c islets to either chemically induced diabetic C57BL/6 mice or spontaneously diabetic non-obese diabetic (NOD) mice. TPT was injected within 2 weeks or continuously, until rejection, in the two combinations. Then, we evaluated the toxicity of TPT on islet function by daily injection to naive BALB/c or diabetic BALB/c that was cured by syngeneic islet transplantation under the kidney capsule. Mice injected with cyclosporine A (CsA) or vehicle served as controls. Intraperitoneal glucose tolerance tests (IPGTTs) performed at 4 and 8 weeks in the naive BALB/c group, and at 2, 4, 6, and 8 weeks in the syngeneic transplanted group. RESULTS: The medium survival time of islets allograft from TPT treated C57BL/6 and NOD recipients were 28.5 days (range 24-30 days, n=10) and 33.0 days (range 15-47 days, n=6), respectively, and they were significantly different from those of the vehicle treated controls, which were 14.0 days (range 13-16 days, n=6) and 5.0 days (range 4-10 days, n=6), respectively (all P<0.0001). The IPGTT demonstrated that there was no difference between the TPT treated and vehicle treated groups, either in the normal or syngeneic transplanted islet BALB/c mice. However, CsA injection impaired islet function in both normal and syngeneic transplanted mice as early as 4 weeks. CONCLUSION: TPT prolonged islets allograft survival in a chemically induced diabetic or an autoimmune diabetic murine model without impairment of islet function. (Hepatobiliary Pancreat Dis Int 2010; 9: 312-318)展开更多
If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanop...If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanoptimal approaches to immunosuppression,recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation.Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention.Progress in stem cell research over the past decade,coupled with our decades-long experience with islet transplantation,is shaping the future of cell therapies for the treatment of diabetes.Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration,including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.展开更多
文摘Type 1 diabetes(T1D)is a chronic,lifelong,autoimmune disease that is debilitating and life-threatening to those who suffer from severe hypoglycaemic events or the devastating chronic complications.Exogenous insulin replacement,including the artificial pancreas,is the current mainstay of T1D therapy but cannot prevent the chronic vascular complications of the disease.They are also responsible for contributing to severe iatrogenic hypoglycaemia and impaired hypoglycaemic awareness.β-cell replacement with either pancreas or islet allotransplantation can reverse diabetes leading to better glycaemic control,prevention of hypoglycaemic events and improved quality of life for patients.The limited supply of cadaveric organ donors is a major barrier to this therapeutic option.Thus,alternative sources of islets are being actively explored,mainly human pluripotent stem-cell derived islets and xenogeneic porcine islets.Although these sources harbor their own risks and problems,various novel and innovative solutions are being perseveringly investigated across the globe to overcome these in the hopes that safe islet transplantation may one day be available to all T1D patients suffering from severe hypoglycaemic events.This review will concentrate on pre-clinical and clinical studies,in addition to the latest scientific discoveries relevant to T1D transplantation therapy using allogeneic or xenogeneic donor islet cells.
基金supported by The Family Erling-Persson FoundationThe Swedish Diabetes Association+9 种基金Funds of Karolinska InstitutetThe Sigurd and Elsa Goljes FoundationThe Swedish Research CouncilNovo Nordisk FoundationStrategic Research Program in Diabetes at Karolinska InstitutetThe Family Knut and Alice Wallenberg FoundationJonas and Christina af Jochnick FoundationThe Bert von Kantzow FoundationSvenska DiabetesstiftelsenThe ERC-EYLETS 834860.
文摘Dear Editor,Type 1 diabetes(T1D)is a complex autoimmune disease characterized by the progressive destruction of pancreaticβ-cells,leading to insulin deficiency.Despite extensive research,the specific triggering factors that initiate and advance T1D remain elusive.Over recent decades,we have observed a concerning global increase in T1D incidence,notable not only for its rising numbers,but also for a concerning trend towards younger age at diagnosis.Transplantation of pancreatic islets to the portal system of the liver is used as a treatment strategy for T1D.However,the success rate has been limited due to poor graft survival,despite immunosuppressive treatment,and often multiple transplantations are needed to obtain adequate secretion of insulin.1 Hence,for islet transplantation to become a viable treatment option for T1D,it is essential to both identify a more suitable transplantation site and develop methods to engineer islets that are resistant to inflammatory and immunological attacks.
文摘BACKGROUND Not all islet transplants desirably achieve insulin independence.This can be attributed to the microarchitecture and function of the islets influenced by their dimensions.Large islets enhance insulin secretion through paracrine effects but are more susceptible to hypoxic injury post-transplant,while small islets offer better viability and insulin independence.In vivo studies suggest large islets are essential for maintaining euglycemia,though smaller islets are typically preferred in transplantation for better outcomes.AIM To document the impact of islet dimension on clinical and preclinical transplant outcomes to optimize procedures.METHODS PubMed,Scopus and EMBASE platforms were searched for relevant literature up to 9 April 2024.Articles reported on either glucose-stimulated insulin-secreting(GSIS)capacity,islet viability and engraftment,or insulin independence based on the islet dimension were included.The risk of bias was measured using the Appraisal Tool for Cross-Sectional Studies.Extracted data was analyzed via a narrative synthesis.RESULTS Nineteen studies were included in the review.A total of sixteen studies reported the GSIS,of which nine documented the increased insulin secretion in the small islet,where the majority reported insulin secretion per islet equivalent(IEQ).Seven studies documented increased GSIS in large-sized islets that measure insulin secretion per cell or islet.All the articles that compared small and large islets reported poor viability and engraftment of large islets.CONCLUSION Small islets with a diameter<125μm have desired transplantation outcomes due to their better survival following isolation.Large-sized islets receive blood supply directly from arterioles in vivo to meet their higher metabolic demands.The large islet undergoes central necrosis soon after the isolation(devascularization);failing to maintain the viability and glucose stimuli leads to a decline in GSIS and the overall function of the islet.Improved preservation of large islets after islet isolation,enhances the islet yield(IEQ),thereby reducing the likelihood of failed islet isolation and potentially improves transplant outcome.
基金Supported by the Special Research Fund, Account Code: 4280, National and Kapodistrian University of Athens, Greece
文摘AIM: To develop an experimental model of islet allotransplantation in diabetic rats and to determine the positive or adverse effects of MMF as a single agent. METHODS: Thirty-six male Wistar rats and 18 male Lewis rats were used as recipients and donors respectively. Diabetes was induced by the use of streptozotocin (60 mg/kg) intraperitoneally. Unpurified islets were isolated using the collagenase digestion technique and transplanted into the splenic parenchyma. The recipients were randomly assigned to one of the following three groups: group A (control group) had no immunosuppression; group B received cyclosporine (CsA) (5 mg/kg); group C receivedmycophenolate mofetil (MMF) (20 mg/kg). The animalswere killed on the 12th d. Blood and grafted tissues were obtained for laboratory and histological assessment. RESULTS: Median allograft survival was significantly higher in the two therapy groups than that in the controls (10 and 12 d for CsA and MMF respectively vs 0 d for the control group, P＜0.01). No difference in allograft survival between the CsA and MMF groups was found. However,MMF had less renal and hepatic toxicity and allowed weight gain.CONCLUSION: Monotherapy with MMF for immunosu ppression was safe in an experimental model of islet allotransplantation and was equally effective with cyclosporine, with less toxicity.
基金Supported by National Natural Science Foundation of China, No. 30672094
文摘AIM: To determine whether the elevated vascular endothelial growth factor (VEGF) expression produced by the transfected vascular endothelial cells (VECs) could stimulate angiogenesis of the graft islets and exert its effect on the graft function. METHODS: Thirty diabetic recipient rats were divided into three groups (n = 10 per group). In the control group,300 IEQ islets were transplanted in each rat under the capsule of the right kidney,which were considered as marginal grafts. In the VEC group,VEC together with the islets were transplanted in each rat. In the VEGF group,VEC transfected by pIRES2-EGFP/ VEGF165 plasmid and the islets were transplanted in each rat. Blood glucose and insulin levels were evaluated every other day after operation. Intravenous glucose tolerance test (IVGTT) was performed 10 d after the transplantation. Hematoxylin and eosin (HE) staining was used to evaluate the histological features of the graft islets. Immunohistochemical staining was used to detect insulin-6,VEGF and CD34 (MVD) expression in the graft islets. RESULTS: Blood glucose and insulin levels in the VEGF group restored to normal 3 d after transplantation. In contrast,diabetic rats receiving the same islets with or without normal VECs displayed moderate hyperglycemia and insulin,without a significant difference between these two groups. IVGTT showed that both the amplitude of blood glucose induction and the kinetics of blood glucose in the VEGF group restored to normal after transplantation. H&E and immunohistochemical staining showed the presence of a large amount of graft islets under the capsule of the kidney,which were positively stained with insulin-6 and VEGF antibodies in the VEGF group. In the cell masses,CD34-stained VECs were observed. The similar masses were also seen in the other two groups,but with a fewer positive cells stained with insulin-6 and CD34 antibodies. No VEGF-positive cells appeared in these groups. Microvessel density (MVD) was significantly higher in the VEGF group compared to the other two groups. CONCLUSION: Elevated VEGF production by trans-fected vascular endothelial cells in the site of islet transplantation stimulates angiogenesis of the islet grafts. The accelerated islet revascularization in early stage could improve the outcome of islet transplantation,and enhance the graft survival.
文摘AIM: To evaluate the safety and feasibility of laparoscopic spleen-preserving distal pancreatectomy (LSPDP) with autologous islet transplantation (AIT) for benign tumors of the pancreatic body-neck.
文摘Transplantation of pancreatic tissue, as either the intact whole pancreas or isolated pancreatic islets has become a clinical option to be considered in the treatment of patients with type 1 insulin-dependant diabetes mellitus. A successful whole pancreas or islet transplant offers the advantages of attaining normal or near normal blood glucose control and normal hemoglobin Alc levels without the risks of severe hypoglycemia associate with intensive insulin therapy. Both forms of transplants are also effective at eliminating the occurrence of significant hypoglycemic events （even with only partial islet function evident）. Whereas whole pancreas transplantation has also been shown to be very effective at maintaining a euglycemic state over a sustained period of time, thus providing an opportunity for a recipient to benefit from improvement of their blood glucose control, it is associated with a significant risk of surgical and post-operative complications. Islet transplantation is attractive as a less invasive alternative to whole pancreas transplant and offers the future promise of immunosuppression-free transplantation through pretransplant culture. Islet transplantation however, may not always achieve the sustained level of tight glucose control necessary for reducing the risk of secondary diabetic complications and exposes the patient to the adverse effects of immunosuppression. Although recent advances have led to an increased rate of obtaining insulin-independence following islet transplantation, further developments are needed to improve the longterm viability and function of the graft to maintain improved glucose control over time.
基金Supported by National Institutes of Health/National Instituteof Diabetes and Digestive and Kidney Diseases (NIH/NIDDK)Grant # 1R01-DK077541 (to Hathout E)a grant from the National Medical Test Bed (to Hathout E)
文摘AIM:To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.METHODS: Streptozotocin induced diabetic BALB/ c mice were transplanted syngeneically under the kidney capsule with the following: (1) 200 islets (islet group: n=12), (2) 1-5×106 bone marrow cells (bone marrow group: n=11), (3) 200 islets and 1-5×106 bone marrow cells (islet + bone marrow group: n= 13), or (4) no cells (sham group:n=5). All mice were evaluated for blood glucose, serum insulin, serum nervegrowth factor (NGF) and glucose tolerance (GTT) up to postoperative day (POD) 14. Histological assessment for insulin, von Willebrand factor (vWF) and NGF was performed at POD 3, 7 and 14.RESULTS: Blood glucose level was lowest and serum insulin was highest in the islet + bone marrow group. Serum NGF increased in islet, bone marrow, and islet + bone marrow groups after transplantation, and there was a significant difference (P=0.0496, ANOVA) between the bone marrow and sham groups. The number of vessels within the graft area was signif icantly increased in both the bone marrow and islet + bone marrow groups at POD 14 as compared to the islet alone group (21.2 ± 3.6 in bone marrow, P=0.01, vs islet group, 22.6 ± 1.9 in islet + bone marrow, P = 0.0003, vs islet group, 5.3 ± 1.6 in islet-alone transplants). NGF was more strongly expressed in bone marrow cells compared with islets. CONCLUSION: Bone marrow cells produce NGF and promote angiogenesis. Islet co-transplantation with bone marrow is associated with improvement of islet graft function.
文摘The purpose of the present study was to organize the parameters involved in experimental allotransplantation in rodents to elaborate the most suitable model to supply the scarcity of islet donors. We used the PubMed database to systematically search for published articles containing the keywords “rodent islet transplantation” to review. We included studies that involved allotransplantation experiments with rodents’ islets, and we reviewed the reference lists from the eligible publications that were retrieved. We excluded articles related to isotransplantation, autotransplantation and xenotransplantation, i.e., transplantation in other species. A total of 25 studies related to allotransplantation were selected for systematic review based on their relevance and updated data. Allotransplantation in rodents is promising and continues to develop. Survival rates of allografts have increased with the discovery of new immunosuppressive drugs and the use of different graft sites. These successes suggest that islet transplantation is a promising method to overcome the scarcity of islet donors and advance the treatment options for type 1 diabetes.
基金Supported by European Union-NextGenerationEU,through The National Recovery and Resilience Plan of the Republic of Bulgaria,No.BG-RRP-2.004-0008-C01.
文摘Pancreatic islet transplantation is a minimally invasive procedure aiming to reverse the effects of insulin deficiency in patients with type 1 diabetes(T1D)by transplanting pancreatic beta cells.Overall,pancreatic islet transplantation has improved to a great extent,and cellular replacement will likely become the mainstay treatment.We review pancreatic islet transplantation as a treatment for T1D and the immunological challenges faced.Published data demonstrated that the time for islet cell transfusion varied between 2 and 10 h.Approximately 54%of the patients gained insulin independence at the end of the first year,while only 20%remained insulin-free at the end of the second year.Eventually,most transplanted patients return to using some form of exogenous insulin within a few years after the transplantation,which imposed the need to improve immunological factors before transplantation.We also discuss the immunosuppressive regimens,apoptotic donor lymphocytes,anti-TIM-1 antibodies,mixed chimerism-based tolerance induction,induction of antigen-specific tolerance utilizing ethylene carbodiimide-fixed splenocytes,pretransplant infusions of donor apoptotic cells,B cell depletion,preconditioning of isolated islets,inducing local immunotolerance,cell encapsulation and immunoisolation,using of biomaterials,immunomodulatory cells,etc.
文摘BACKGROUND: The most common complication after allogenic islet transplantation is rejection. This study was to evaluate the effect of anti-rejection of glucocorticoid-free immunosuppressive regimen on allogenic islet transplantation. METHODS: Tacrolimus(FK506)+mycophenolate mofetil (MMF) and FK506+MMF+prednisone (Pred) were administered respectively for 2 weeks to inhibit rejection after allogenic islet transplantation in rats, which were compared with the control group. The concentrations of blood glucose, insulin and C-peptide were determined dynamically in recipients and the sites of transplantation were observed morphologically. RESULTS: As compared with the control group without immunosuppressive agents, FK506+MMF and FK506+MMF+Pred could prolong the survival time of grafts significantly. There were many morphologically intact islets in the liver of recipients 2 months after transplantation. Group FK506+MMF kept normal levels of blood glucose, insulin and C-peptide beyond 60 days after transplantation. In contrast, group FK506+MMF+Pred secreted less C-peptide(P<0.05) and maintained a higher level of blood glucose concentration (P<0.01) after the operation. There was no significant difference in insulin concentrations between the two groups. The level of blood glucose beyond the first 2 weeks after drug withdrawal in group FK506+MMF+Pred decreased obviously (P<0.05), and the secretion of insulin and C-peptide increased. These results were compared with those the first 2 weeks after transplantation and the first 2 weeks after drug withdrawal. CONCLUSIONS: Both regimens of FK506+MMF and FK506+MMF+Pred could provide effective immunosup-pression. Moreover the combined glucocorticoid-free immunosuppressive strategy of low-dose FK506 and MMF could protect islet grafts in islet transplantation without diabetogenic side-effects.
基金The project was supported by a grant from the NationalNatural Scientific Foundation (30371359).
文摘BACKGROUND: Islet transplantation is considered a po- tentially curative treatment for diabetic mellitus. The aim of this study was to assess the feasibility of islet transplant through the spleen. METHODS: Both donor and recipient Wistar rats (BW150± 20 g) were provided by the Animal Center of China Medi- cal University, Shenyang, China. Islets were isolated and purified with the modified Minnesota program. 600-800IE graft islets were handpicked and transplanted through the spleen of diabetic recipients. Blood glucose and insulin were evaluated after operation every other day. IVGTT was performed 10 days after transplantation. RESULTS: 300-400IE islet was procured from one donor rat. Secretion index (SI) of the glucose stress was 5.59± 0.62, showing the graft functioning well. The diabetic rats restored normal blood glucose levels of 3.4-5.4 mmol/L (mean 4.8 mmol/L). Their insulin levels were as normal as 8.5-12.2 μIU/ml. The K value of IVGTT in the rats after transplantation was similar to the normal one. CONCLUSIONS: The islets can be transplanted successfully through the spleen, while avoiding the complications caused by traditional transplantation through the portal vein, such as bleeding and portal vein hypertension. The graft islets loss can be reduced because of less centrifugation and mechanic pressure. In conclusion, transplantation through the spleen is a simple and feasible method.
文摘The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging the preservation time. In a canine model, the TLM was shown to repair and resuscitate warm ischemically damaged pancreata during preservation, improve pancreas graft survival after transplantation, and also improve the islet yield after isolation. Clinical trials using the TLM in pancreas preservation before whole-pancreas transplantation and islet isolation have shown promising outcomes. We describe the role of the TLM in pancreas and islet transplantation.
文摘AIM: To evaluate pain control in chronic pancreatitis patients who underwent total pancreatectomy with islet cell transplantation or intrathecal narcotic pump infusion.METHODS: We recognized 13 patients who underwent intrathecal narcotic pump(ITNP) infusion and 57 patients who underwent total pancreatectomy with autologous islet cell transplantation(TP + ICT) for chronic pancreatitis(CP) pain control between 1998 and 2008 at Indiana University Hospital. All patients had already failed multiple other modalities for pain control and the decision to proceed with either intervention was made at the discretion of the patients and their treating physicians. All patients were evaluated retrospectively using a questionnaire inquiring about their pain control(using a 0-10 pain scale), daily narcotic dose usage, and hospital admission days for pain control before each intervention and during their last follow-up. RESULTS: All 13 ITNP patients and 30 available TP + ICT patients were evaluated. The mean age was approximately 40 years in both groups. The median duration of pain before intervention was 6 years and 7 years in the ITNP and TP + ICT groups, respectively. The median pain score dropped from 8 to 2.5(on a scale of 0-10) in both groups on their last follow up. The median daily dose of narcotics also decreased from 393 mg equivalent of morphine sulfate to 8 mg in the ITNP group and from 300 mg to 40 mg in the TP + ICT group. No patient had diabetes mellitus(DM) before either procedure whereas 85% of those who underwent pancreatectomy were insulin dependent on their last evaluation despite ICT. CONCLUSION: ITNP and TP + ICT are comparable for pain control in patients with CP however with high incidence of DM among those who underwent TP + ICT. Prospective comparative studies and longer follow up are needed to better define treatment outcomes.
文摘Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabetes.The countries where islet transplantation has not been explored suffer from insufficient knowledge concerning key elements of the isolation process.Donor and organ procurement parameters impact human islet yield,although for research purposes,islet yield may be secondary in importance to islet function.This paper will analyze the feasibility of research-only human islet isolation and signify parameters underlying a successful yield in the Indian population.This eventually can make islet transplantation a clinical reality in India.Method:After receiving the consent for procuring brain-dead pancreas from the first-degree of relatives,samples were collected and transported in a transportation buffer at 4℃.The procedure consists of a mechanically enhanced enzymatic digestion of the pancreas,after which it was taken for purification using Ficoll method,followed by islet quality testing.Results:Through 15 isolations done over a span of approximately 2 years during the COVID pandemic in India,we confirm that ischemic time and glycated hemoglobin,each have a negative impact on isolation purity and yield.Notably,extending cold ischemic tim beyond the typical clinical isolation cutoff of 12 hours(to≥18 h)had a huge impact on islet function and yield.Age had a negative correlation with islet yield;however other biological parameters(specifically body mass index)and isolation variables appear to make a significant contribution to the heterogeneity of human islet yield.Our current work demonstrates the feasibility of extending acceptable cold ischemic time for research-focused human islet isolation and highlights the biological variation in isolation of human islets from donors with and without diabetes.Conclusion:India requires establishment of an islet transplant program using the current standard methods of“islet isolation”and donor program and process.Research should focus on improving standards in the islet preparation process to increase the number of successful preparations,shorten the isolation time,and increase patient safety so that the theoretical risk involved can become a practical reality.
文摘Diabetes is a heterogeneous metabolic disease characterized by elevated blood glucose levels resulting from the destruction or malfunction of pancreaticβcells,insulin resistance in peripheral tissues,or both,and results in a non-sufficient production of insulin.To adjust blood glucose levels,diabetic patients need exogenous insulin administration together with medical nutrition therapy and physical activity.With the aim of improving insulin availability in diabetic patients as well as ameliorating diabetes comorbidities,different strategies have been investigated.The first approaches included enhancing endogenousβcell activity or transplanting new islets.The protocol for this kind of intervention has recently been optimized,leading to standardized procedures.It is indicated for diabetic patients with severe hypoglycemia,complicated by impaired hypoglycemia awareness or exacerbated glycemic lability.Transplantation has been associated with improvement in all comorbidities associated with diabetes,quality of life,and survival.However,different trials are ongoing to further improve the beneficial effects of transplantation.Furthermore,to overcome some limitations associated with the availability of islets/pancreas,alternative therapeutic strategies are under evaluation,such as the use of mesenchymal stem cells(MSCs)or induced pluripotent stem cells for transplantation.The cotransplantation of MSCs with islets has been successful,thus providing protection against proinflammatory cytokines and hypoxia through different mechanisms,including exosome release.The use of induced pluripotent stem cells is recent and requires further investigation.The advantages of MSC implantation have also included the improvement of diabetes-related comorbidities,such as wound healing.Despite the number of advantages of the direct injection of MSCs,new strategies involving biomaterials and scaffolds have been developed to improve the efficacy of mesenchymal cell delivery with promising results.In conclusion,this paper offered an overview of new alternative strategies for diabetes management while highlighting some limitations that will need to be overcome by future approaches.
文摘I have read with great interest the paper by Pollard et al.(1)published in Hepatobiliary Surgery and Nutrition.This is a retrospective single-center study presenting 10-year follow-up of 60 patients undergoing total pancreatectomy with autologous islet transplantation(TPAIT)in the University Hospital of Leicester,one of the most experienced in TPAIT centers in the world.The patients had undergone TPAIT between September 1994 to May 2011(1).The completed 10-year assessment was achieved in 17 patients who were grouped by the authors using the modified Auto-Igls criteria;good response,n=5(insulin-independent for first 5 years post-TPAIT);partial response,n=6(insulin requirements<20 IU/day post-TPAIT)and poor response,n=6(insulin requirements≥20 IU/day post-TPAIT).
基金supported by the National Natural Science Foundation Major International(Regional)Joint Research Program(82320108003)the National Natural Science Foundation of China(82170845)+2 种基金the Key Research&Development Program(BE2022853)Medical Key Discipline(ZDXK202203)of Jiangsu ProvinceResearch Personnel Cultivation Program of Zhongda Hospital Southeast University(CZXM-GSP-RC165,CZXM-JDBF-zdlyg18,and CZXM-GSP-LCYJFH02)。
文摘Current research on islet transplantation is aimed at prolonging the survival time and enhancing the functionality of the transplantation system.Owing to the good biocompatibility of hydrogels and their ability to provide mechanical support and immunological isolation of islet cells,hydrogel encapsulation of islets offers an innovative solution for islet transplantation.In this work,inspired by the extracellular matrix structure of the pancreatic islets,an injectable self-healing hydrogel loaded with islet-integrated microfiber scaffolds was constructed for islet transplantation.The short microfiber was fabricated by introducing a gaseous phase into microfluidic spinning,causing the continuous microfibers to break into short segments due to bubble rupture.These short microfibers provide mechanical support for pancreatic islets and can be integrated into a self-healing matrix to form a vascularized hydrogel through Schiff base bonding of oxidized sodium alginate aldehyde groups with carboxymethyl chitosan amino groups.With the loading of human umbilical vein endothelial cells and vascular endothelial growth factor,this composite is both injectable and provides mechanical support for the grafts,extends islet survival time,and improves islet function.In vivo experiments further confirm that this bioinspired composite system minimizes implantation-associated trauma while promoting neovascularization at the graft site in diabetic rodents,thereby achieving prolonged glycemic control compared to non-vascularized systems.These findings demonstrate that this hierarchically structured multifunctional graft platform has substantial research value and extensive therapeutic potential in the fields of cell therapy and tissue engineering for the treatment of diabetes and related diseases.
文摘BACKGROUND: Triptolide (TPT) is a diterpenoid triepoxide extracted from the Chinese herb Tripterygium wilfordii Hook. F. It exhibits potent immunosuppressive and anti-inflammatory properties. This study was undertaken to investigate its effects on prolongation of islet allograft survival in rodents. Additionally, we investigated whether TPT would be toxic to islet function in vivo. METHODS: We transplanted BALB/c islets to either chemically induced diabetic C57BL/6 mice or spontaneously diabetic non-obese diabetic (NOD) mice. TPT was injected within 2 weeks or continuously, until rejection, in the two combinations. Then, we evaluated the toxicity of TPT on islet function by daily injection to naive BALB/c or diabetic BALB/c that was cured by syngeneic islet transplantation under the kidney capsule. Mice injected with cyclosporine A (CsA) or vehicle served as controls. Intraperitoneal glucose tolerance tests (IPGTTs) performed at 4 and 8 weeks in the naive BALB/c group, and at 2, 4, 6, and 8 weeks in the syngeneic transplanted group. RESULTS: The medium survival time of islets allograft from TPT treated C57BL/6 and NOD recipients were 28.5 days (range 24-30 days, n=10) and 33.0 days (range 15-47 days, n=6), respectively, and they were significantly different from those of the vehicle treated controls, which were 14.0 days (range 13-16 days, n=6) and 5.0 days (range 4-10 days, n=6), respectively (all P<0.0001). The IPGTT demonstrated that there was no difference between the TPT treated and vehicle treated groups, either in the normal or syngeneic transplanted islet BALB/c mice. However, CsA injection impaired islet function in both normal and syngeneic transplanted mice as early as 4 weeks. CONCLUSION: TPT prolonged islets allograft survival in a chemically induced diabetic or an autoimmune diabetic murine model without impairment of islet function. (Hepatobiliary Pancreat Dis Int 2010; 9: 312-318)
基金Supported by Funding of the National Institutes of Healththe Juvenile Diabetes Research Foundation+2 种基金the American Diabetes Associationthe Foundation for Diabetes Researchthe Diabetes Research Institute Foundation
文摘If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanoptimal approaches to immunosuppression,recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation.Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention.Progress in stem cell research over the past decade,coupled with our decades-long experience with islet transplantation,is shaping the future of cell therapies for the treatment of diabetes.Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration,including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.
