Islet transplantation stabilizes hemostatic abnormalities and cerebral metabolism in individuals with type 1 diabetes

Diabetes current and future translatable therapies

Diabetes is one of the major diseases and concerns of public health systems that affects over 200 million patients worldwide. It is estimated that 90% of these patients suffer from diabetes type 2, while 10% present diabetes type 1. This type of diabetes and certain types of diabetes type 2, are characterized by dysregulation of blood glycemic levels due to the total or partial depletion of insulin-secreting pancreatic β-cells. Different approaches have been proposed for long-term treatment of insulin-dependent patients; amongst them, cell-based approaches have been the subject of basic and clinical research since they allow blood glucose level sensing and in situ insulin secretion. The current gold standard for insulin-dependent patients is on-demand exogenous insulin application; cell-based therapies aim to remove this burden from the patient and caregivers. In recent years, protocols to isolate and implant pancreatic islets from diseased donors have been developed and tested in clinical trials. Nevertheless, the shortage of donors, along with the need of immunosuppressive companion therapies, have pushed researchers to focus their attention and efforts to overcome these disadvantages and develop alternative strategies. This review discusses current tested clinical approaches and future potential alternatives for diabetes type 1, and some diabetes type 2, insulin-dependent patients. Additionally, advantages and disadvantages of these discussed methods.

Thyroid Hormone Levels Correlate With the Maturation of Implanted Pancreatic Endoderm Cells in Patients With Type 1 Diabetes

BACKGROUND

Macroencapsulated pancreatic endoderm cells (PECs) can reverse diabetes in rodents and preclinical studies revealed that thyroid hormones in vitro and in vivo bias PECs to differentiate into insulin-producing cells. In an ongoing clinical trial, PECs implanted in macroencapsulation devices into patients with type 1 diabetes were safe but yielded heterogeneous outcomes. Though most patients developed meal responsive C-peptide, levels were heterogeneous and explanted grafts had variable numbers of surviving cells with variable distribution of endocrine cells.

METHODS

We measured circulating triiodothyronine and thyroxine levels in all patients treated at 1 of the 7 sites of the ongoing clinical trial and determined if thyroid hormone levels were associated with the C-peptide or glucagon levels and cell fate of implanted PECs.

RESULTS

Both triiodothyronine and thyroxine levels were significantly associated with the proportion of cells that adopted an insulin-producing fate with a mature phenotype. Thyroid hormone levels were inversely correlated to circulating glucagon levels after implantation, suggesting that thyroid hormones lead PECs to favor an insulin-producing fate over a glucagon-producing fate. In mice, hyperthyroidism led to more rapid maturation of PECs into insulin-producing cells similar in phenotype to PECs in euthyroid mice.

CONCLUSION

These data highlight the relevance of thyroid hormones in the context of PEC therapy in patients with type 1 diabetes and suggest that a thyroid hormone adjuvant therapy may optimize cell outcomes in some PEC recipients.

Advancements in innate immune regulation strategies in islet transplantation

As a newly emerging organ transplantation technique, islet transplantation has shown the advantages of minimal trauma and high safety since it was first carried out. The proposal of the Edmonton protocol, which has been widely applied, was a breakthrough in this method. However, direct contact between islets and portal vein blood will cause a robust innate immune response leading to massive apoptosis of the graft, and macrophages play an essential role in the innate immune response. Therefore, therapeutic strategies targeting macrophages in the innate immune response have become a popular research topic in recent years. This paper will summarize and analyze recent research on strategies for regulating innate immunity, primarily focusing on macrophages, in the field of islet transplantation, including drug therapy, optimization of islet preparation process, islet engineering and Mesenchymal stem cells cotransplantation. We also expounded the heterogeneity, plasticity and activation mechanism of macrophages in islet transplantation, providing a theoretical basis for further research.

Allo Beta Cell transplantation: specific features, unanswered questions, and immunological challenge

Type 1 diabetes (T1D) presents a persistent medical challenge, demanding innovative strategies for sustained glycemic control and enhanced patient well-being. Beta cells are specialized cells in the pancreas that produce insulin, a hormone that regulates blood sugar levels. When beta cells are damaged or destroyed, insulin production decreases, which leads to T1D. Allo Beta Cell Transplantation has emerged as a promising therapeutic avenue, with the goal of reinstating glucose regulation and insulin production in T1D patients. However, the path to success in this approach is fraught with complex immunological hurdles that demand rigorous exploration and resolution for enduring therapeutic efficacy. This exploration focuses on the distinct immunological characteristics inherent to Allo Beta Cell Transplantation. An understanding of these unique challenges is pivotal for the development of effective therapeutic interventions. The critical role of glucose regulation and insulin in immune activation is emphasized, with an emphasis on the intricate interplay between beta cells and immune cells. The transplantation site, particularly the liver, is examined in depth, highlighting its relevance in the context of complex immunological issues. Scrutiny extends to recipient and donor matching, including the utilization of multiple islet donors, while also considering the potential risk of autoimmune recurrence. Moreover, unanswered questions and persistent gaps in knowledge within the field are identified. These include the absence of robust evidence supporting immunosuppression treatments, the need for reliable methods to assess rejection and treatment protocols, the lack of validated biomarkers for monitoring beta cell loss, and the imperative need for improved beta cell imaging techniques. In addition, attention is drawn to emerging directions and transformative strategies in the field. This encompasses alternative immunosuppressive regimens and calcineurin-free immunoprotocols, as well as a reevaluation of induction therapy and recipient preconditioning methods. Innovative approaches targeting autoimmune recurrence, such as CAR Tregs and TCR Tregs, are explored, along with the potential of stem stealth cells, tissue engineering, and encapsulation to overcome the risk of graft rejection. In summary, this review provides a comprehensive overview of the inherent immunological obstacles associated with Allo Beta Cell Transplantation. It offers valuable insights into emerging strategies and directions that hold great promise for advancing the field and ultimately improving outcomes for individuals living with diabetes.

Benefits and Hurdles of Pancreatic β-Cell Replacement

Insulin represents a life-saving treatment in patients with type 1 diabetes, and technological advancements have improved glucose control in an increasing number of patients. Despite this, adequate control is often still difficult to achieve and insulin remains a therapy and not a cure for the disease. β-cell replacement strategies can potentially restore pancreas endocrine function and aim to maintain normoglycemia; both pancreas and islet transplantation have greatly progressed over the last decades and, in subjects with extreme glycemic variability and diabetes complications, represent a concrete and effective treatment option. Some issues still limit the adoption of this approach on a larger scale. One is represented by the strict selection criteria for the recipient who can benefit from a transplant and maintain the lifelong immunosuppression necessary to avoid organ rejection. Second, with regard to islet transplantation, up to 40% of islets can be lost during hepatic engraftment. Recent studies showed very preliminarily but promising results to overcome these hurdles: the ability to induce β-cell maturation from stem cells may represent a solution to the organ shortage, and the creation of semi-permeable membranes that envelope or package cells in either micro- or macro- encapsulation strategies, together with engineering cells to be hypo-immunogenic, pave the way for developing strategies without immunosuppression. The aim of this review is to describe the state of the art in β-cell replacement with a focus on its efficacy and clinical benefits, on the actual limitations and still unmet needs, and on the latest findings and future directions.

Abnormalities of the oculomotor function in type 1 diabetes and diabetic neuropathy

AIMS

Abnormalities in the oculomotor system may represent an early sign of diabetic neuropathy and are currently poorly studied. We designed an eye-tracking-based test to evaluate oculomotor function in patients with type 1 diabetes.

METHODS

We used the SRLab-Tobii TX300 Eye tracker®, an eye-tracking device, coupled with software that we developed to test abnormalities in the oculomotor system. The software consists of a series of eye-tracking tasks divided into 4 classes of parameters (Resistance, Wideness, Pursuit and Velocity) to evaluate both smooth and saccadic movement in different directions. We analyzed the oculomotor system in 34 healthy volunteers and in 34 patients with long-standing type 1 diabetes.

RESULTS

Among the 474 parameters analyzed with the eye-tracking-based system, 11% were significantly altered in patients with type 1 diabetes (p < 0.05), with a higher proportion of abnormalities observed in the Wideness (24%) and Resistance (10%) parameters. Patients with type 1 diabetes without diabetic neuropathy showed more frequently anomalous measurements in the Resistance class (p = 0.02). The classes of Velocity and Pursuit were less frequently altered in patients with type 1 diabetes as compared to healthy subjects, with anomalous measurements mainly observed in patients with diabetic neuropathy.

CONCLUSIONS

Abnormalities in oculomotor system function can be detected in patients with type 1 diabetes using a novel eye-tracking-based test. A larger cohort study may further determine thresholds of normality and validate whether eye-tracking can be used to non-invasively characterize early signs of diabetic neuropathy.

TRIAL

NCT04608890.

Cell Therapy for Type 1 Diabetes: From Islet Transplantation to Stem Cells

The field of cell therapy of type 1 diabetes is a particularly interesting example in the scenario of regenerative medicine. In fact, β-cell replacement has its roots in the experience of islet transplantation, which began 40 years ago and is currently a rapidly accelerating field, with several ongoing clinical trials using β cells derived from stem cells. Type 1 diabetes is particularly suitable for cell therapy as it is a disease due to the deficiency of only one cell type, the insulin-producing β cell, and this endocrine cell does not need to be positioned inside the pancreas to perform its function. On the other hand, the presence of a double immunological barrier, the allogeneic one and the autoimmune one, makes the protection of β cells from rejection a major challenge. Until today, islet transplantation has taught us a lot, pioneering immunosuppressive therapies, graft encapsulation, tissue engineering, and test of different implant sites and has stimulated a great variety of studies on β-cell function. This review starts from islet transplantation, presenting its current indications and the latest published trials, to arrive at the prospects of stem cell therapy, presenting the latest innovations in the field.

The IGFBP3/TMEM219 pathway regulates beta cell homeostasis

Loss of pancreatic beta cells is a central feature of type 1 (T1D) and type 2 (T2D) diabetes, but a therapeutic strategy to preserve beta cell mass remains to be established. Here we show that the death receptor TMEM219 is expressed on pancreatic beta cells and that signaling through its ligand insulin-like growth factor binding protein 3 (IGFBP3) leads to beta cell loss and dysfunction. Increased peripheral IGFBP3 was observed in established and at-risk T1D/T2D patients and was confirmed in T1D/T2D preclinical models, suggesting that dysfunctional IGFBP3/TMEM219 signaling is associated with abnormalities in beta cells homeostasis. In vitro and in vivo short-term IGFBP3/TMEM219 inhibition and TMEM219 genetic ablation preserved beta cells and prevented/delayed diabetes onset, while long-term IGFBP3/TMEM219 blockade allowed for beta cell expansion. Interestingly, in several patients' cohorts restoration of appropriate IGFBP3 levels was associated with improved beta cell function. The IGFBP3/TMEM219 pathway is thus shown to be a physiological regulator of beta cell homeostasis and is also demonstrated to be disrupted in T1D/T2D. IGFBP3/TMEM219 targeting may therefore serve as a therapeutic option in diabetes.

Next-gen therapeutics to spare and expand beta-cell mass

The most effective and physiological way to treat hyperglycemia is to restore beta-cell function and to rescue production of endogenous insulin. Increasing evidence suggests that both type 1 and type 2 diabetes are characterized by a significant defect in beta-cell mass, leading to the manifestation of the disease. Novel alternative approaches are needed to spare and expand beta-cell mass in patients with diabetes. This review sets out to describe the latest findings on how to restore the beta-cell mass and function in both forms of diabetes to modulate their progression.

Felix dies natalis, insulin… ceterum autem censeo "beta is better"

One hundred years after its discovery, insulin remains the life-saving therapy for many patients with diabetes. It has been a 100-years-old success story thanks to the fact that insulin therapy has continuously integrated the knowledge developed over a century. In 1982, insulin becomes the first therapeutic protein to be produced using recombinant DNA technology. The first "mini" insulin pump and the first insulin pen become available in 1983 and 1985, respectively. In 1996, the first generation of insulin analogues were produced. In 1999, the first continuous glucose-monitoring device for reading interstitial glucose was approved by the FDA. In 2010s, the ultra-long action insulins were introduced. An equally exciting story developed in parallel. In 1966. Kelly et al. performed the first clinical pancreas transplant at the University of Minnesota, and now it is a well-established clinical option. First successful islet transplantations in humans were obtained in the late 1980s and 1990s. Their ability to consistently re-establish the endogenous insulin secretion was obtained in 2000s. More recently, the possibility to generate large numbers of functional human β cells from pluripotent stem cells was demonstrated, and the first clinical trial using stem cell-derived insulin producing cell was started in 2014. This year, the discovery of this life-saving hormone turns 100 years. This provides a unique opportunity not only to celebrate this extraordinary success story, but also to reflect on the limits of insulin therapy and renew the commitment of the scientific community to an insulin free world for our patients.

Effects of islet transplantation on microvascular and macrovascular complications in type 1 diabetes

Type 1 diabetes is associated with high morbidity and mortality from microvascular and macrovascular disease with considerable economic cost to society. Islet cell transplantation (ICT) is a treatment option recommended by National Institute for Health and Care Excellence (NICE) for people with debilitating hypoglycaemia due to type 1 diabetes, including those with renal failure where kidney transplantation may also be indicated. The primary aim of ICT is to improve glycaemic control, reduce severe hypoglycaemia, stabilise glycaemic variability and restore awareness of hypoglycaemia where this is compromised. Insulin independence, although not a primary aim, should also be considered a therapeutic goal. The impact ICT has on the progression of microvascular and macrovascular diabetes complications is derived from small studies and has not been examined in large clinical trials. Lifelong immunosuppression, which is necessary to avoid transplant rejection, has adverse effects on lipid metabolism, hypertension and renal function, which must also be considered. In this review, we discuss the role of ICT in type 1 diabetes management and the available evidence with respect to microvascular and macrovascular disease progression post-transplantation. We conclude that, following ICT, microvascular complications including retinopathy and neuropathy are stabilised or improved. Effects on nephropathy can be complicated by coexisting kidney transplantation and the impact of immunosuppression, the latter leading to an early decline in renal function; however, there is evidence to suggest stable renal outcomes in the long term. Short-term studies have demonstrated a positive impact of ICT on surrogate markers of macrovascular disease; however, long-term studies and trials in this area are lacking.

Acute and long-term disruption of glycometabolic control after SARS-CoV-2 infection

Patients with coronavirus disease 2019 (COVID-19) are reported to have a greater prevalence of hyperglycaemia. Cytokine release as a consequence of severe acute respiratory syndrome coronavirus 2 infection may precipitate the onset of metabolic alterations by affecting glucose homeostasis. Here we describe abnormalities in glycometabolic control, insulin resistance and beta cell function in patients with COVID-19 without any pre-existing history or diagnosis of diabetes, and document glycaemic abnormalities in recovered patients 2 months after onset of disease. In a cohort of 551 patients hospitalized for COVID-19 in Italy, we found that 46% of patients were hyperglycaemic, whereas 27% were normoglycaemic. Using clinical assays and continuous glucose monitoring in a subset of patients, we detected altered glycometabolic control, with insulin resistance and an abnormal cytokine profile, even in normoglycaemic patients. Glycaemic abnormalities can be detected for at least 2 months in patients who recovered from COVID-19. Our data demonstrate that COVID-19 is associated with aberrant glycometabolic control, which can persist even after recovery, suggesting that further investigation of metabolic abnormalities in the context of long COVID is warranted.

Ten-Year Outcome of Islet Alone or Islet After Kidney Transplantation in Type 1 Diabetes: A Prospective Parallel-Arm Cohort Study

OBJECTIVE

The long-term outcome of allogenic islet transplantation is unknown. The aim of this study was to evaluate the 10-year outcome of islet transplantation in patients with type 1 diabetes and hypoglycemia unawareness and/or a functioning kidney graft.

RESEARCH DESIGN AND METHODS

We enrolled in this prospective parallel-arm cohort study 28 subjects with type 1 diabetes who received islet transplantation either alone (ITA) or after a kidney graft (IAK). Islet transplantation consisted of two or three intraportal infusions of allogenic islets administered within (median [interquartile range]) 68 days (43-92). Immunosuppression was induced with interleukin-2 receptor antibodies and maintained with sirolimus and tacrolimus. The primary outcome was insulin independence with A1C ≤6.5% (48 mmol/mol). Secondary outcomes were patient and graft survival, severe hypoglycemic events (SHEs), metabolic control, and renal function.

RESULTS

The primary outcome was met by (Kaplan-Meier estimates [95% CI]) 39% (22-57) and 28% (13-45) of patients 5 and 10 years after islet transplantation, respectively. Graft function persisted in 82% (62-92) and 78% (57-89) of case subjects after 5 and 10 years, respectively, and was associated with improved glucose control, reduced need for exogenous insulin, and a marked decrease of SHEs. ITA and IAK had similar outcomes. Primary graft function, evaluated 1 month after the last islet infusion, was significantly associated with the duration of graft function and insulin independence.

CONCLUSIONS

Islet transplantation with the Edmonton protocol can provide 10-year markedly improved metabolic control without SHEs in three-quarters of patients with type 1 diabetes, kidney transplanted or not.

Islet Transplantation Alone Versus Solitary Pancreas Transplantation: an Outcome-Driven Choice?

PURPOSE OF REVIEW

In patients with type 1 diabetes with extreme glycemic variability, the restoration of pancreas endocrine function is potentially and completely achieved with islets of Langerhans (tissue derived from whole organ) or pancreas (whole organ) transplantation. The aim of our review is to report on the latest studies and to highlight the benefits and risks of the two procedures, providing clearer, more selective, evidence-based clinical indications that also consider the impact on the degenerative complications of diabetes as a potential benefit.

RECENT FINDINGS

Clinical experience in this field has been dynamic over the last three decades, and has been characterized by the development of more standardized protocols and a clearer definition of clinical outcome. On the contrary, the recommendations thus far are not well delineated and tend to overlap, and the past ADA position statement for pancreas transplant alone has also been applied to islet transplant alone, without differentiation. Both outcome-driven and non-outcome-driven criteria are considered in the conclusions, in an attempt to streamline indications for islet-alone or pancreas-alone transplantation.

Islet-Derived eATP Fuels Autoreactive CD8+ T Cells and Facilitates the Onset of Type 1 Diabetes

Extracellular ATP (eATP) activates T cells by engaging the P2X7R receptor. We identified two loss-of-function P2X7R mutations that are protective against type 1 diabetes (T1D) and thus hypothesized that eATP/P2X7R signaling may represent an early step in T1D onset. Specifically, we observed that in patients with newly diagnosed T1D, P2X7R is upregulated on CD8⁺ effector T cells in comparison with healthy control subjects. eATP is released at high levels by human/murine islets in vitro in high-glucose/inflammatory conditions, thus upregulating P2X7R on CD8⁺ T cells in vitro. P2X7R blockade with oxidized ATP reduces the CD8⁺ T cell-mediated autoimmune response in vitro and delays diabetes onset in NOD mice. Autoreactive CD8⁺ T-cell activation is highly dependent upon eATP/P2X7R-mediated priming, while a novel sP2X7R recombinant protein abrogates changes in metabolism and the autoimmune response associated with CD8⁺ T cells. eATP/P2X7R signaling facilitates the onset of autoimmune T1D by fueling autoreactive CD8⁺ cells and therefore represents a novel targeted therapeutic for the disorder.

Covered stenting and transcatheter embolization of splenic artery aneurysms in diabetic patients: A review of endovascular treatment of visceral artery aneurysms in the current era

Diabetes mellitus is associated with both microvascular and macrovascular complications, which can result in visceral aneurysms as for example splenic artery aneurysms: in their management, an endovascular treatment, less invasive than surgery, is generally preferred. Endovascular treatment of splenic artery aneurysms can be based either on covered stenting (CS) or transcatheter embolization (TE). CS generally allows aneurysm exclusion with vessel preservation, while TE usually determines target artery occlusion with potential risk of distal ischemia. We performed a review of the existing literature on endovascular treatment of visceral artery aneurysms (VAAs) and psudoaneurysms (VAPAs) in the current era.

Insulin-mimetic effects of short-term rapamycin in type 1 diabetic patients prior to islet transplantation

BACKGROUND

The immunosuppressive drug rapamycin may influence insulin sensitivity in insulin-responsive tissues.

AIMS

This study aimed at evaluating the effectiveness of rapamycin pre-treatment before pancreatic islet allotransplantation (ITx) in patients with type 1 diabetes mellitus (T1DM).

METHODS

Forty-one T1DM patients were studied. Thirteen patients with poor glycemic control underwent a short-term rapamycin treatment before ITx (Group 1), and they were compared to 28 patients undergoing ITx without rapamycin pre-treatment (Group 2). Outcomes were daily insulin requirement (DIR), fasting blood glucose, HbA1c, C-peptide and the SUITO index of beta-cell function. A subgroup of patients pre-treated with rapamycin before ITx underwent euglycemic hyperinsulinemic clamp with [6,6-²H₂] glucose before and after ITx to evaluate insulin sensitivity.

RESULTS

We found a significant reduction in DIR after rapamycin pre-treatment (- 8 ± 6 U/day, mean ± SD, p < 0.001) and 1 year after ITx. DIR reduction 1 year after ITx was greater in Group 1 as compared to Group 2 (- 37 ± 15 vs. - 19 ± 13 U/day, p = 0.005) and remained significant after adjusting for gender, age, glucose and baseline HbA1c (beta = 18.2 ± 5.9, p = 0.006). Fasting glucose and HbA1c significantly decreased 1 year after ITx in Group 1 (HbA1c: - 2.1 ± 1.4%, p = 0.002), while fasting C-peptide (+0.5 ± 0.3 nmol/l, p = 0.002) and SUITO index increased (+57.4 ± 39.7, p = 0.016), without differences between the two groups. Hepatic glucose production decreased after rapamycin pre-treatment (- 1.1 ± 1.1 mg/kg/min, p = 0.04) and after ITx (- 1.6 ± 0.6 mg/kg/min, p = 0.015), while no changes in peripheral glucose disposal were observed.

CONCLUSIONS

Rapamycin pre-treatment before ITx succeeds in reducing insulin requirement, enhancing hepatic insulin sensitivity. This treatment may improve short-term ITx outcomes, possibly in selected patients with T1DM complicated by insulin resistance.

CLINICAL TRIAL

Clinicaltrials.gov NCT01060605; NCT00014911.

Exocytosis Protein DOC2B as a Biomarker of Type 1 Diabetes

CONTEXT

Efforts to preserve β-cell mass in the preclinical stages of type 1 diabetes (T1D) are limited by few blood-derived biomarkers of β-cell destruction.

OBJECTIVE

Platelets are proposed sources of blood-derived biomarkers for a variety of diseases, and they show distinct proteomic changes in T1D. Thus, we investigated changes in the exocytosis protein, double C2 domain protein-β (DOC2B) in platelets and islets from T1D humans, and prediabetic nonobese diabetic (NOD) mice.

DESIGN, PATIENTS, AND MAIN OUTCOME MEASURE

Protein levels of DOC2B were assessed in platelets and islets from prediabetic NOD mice and humans, with and without T1D. Seventeen new-onset T1D human subjects (10.3 ± 3.8 years) were recruited immediately following diagnosis, and platelet DOC2B levels were compared with 14 matched nondiabetic subjects (11.4 ± 2.9 years). Furthermore, DOC2B levels were assessed in T1D human pancreatic tissue samples, cytokine-stimulated human islets ex vivo, and platelets from T1D subjects before and after islet transplantation.

RESULTS

DOC2B protein abundance was substantially reduced in prediabetic NOD mouse platelets, and these changes were mirrored in the pancreatic islets from the same mice. Likewise, human DOC2B levels were reduced over twofold in platelets from new-onset T1D human subjects, and this reduction was mirrored in T1D human islets. Cytokine stimulation of normal islets reduced DOC2B expression ex vivo. Remarkably, platelet DOC2B levels increased after islet transplantation in patients with T1D.

CONCLUSIONS

Reduction of DOC2B is an early feature of T1D, and DOC2B abundance may serve as a valuable in vivo indicator of β-cell mass and an early biomarker of T1D.

Effect of post-transplant glycemic control on long-term clinical outcomes in kidney transplant recipients with diabetic nephropathy: A multicenter cohort study in Korea

PURPOSE

Diabetic nephropathy is the leading cause of end stage renal disease. The number of kidney transplantation (KT) due to diabetic nephropathy is increasing and there is debate on glycemic control after KT. In this study, we used a multi-center database to determine the relationship between post-transplant glycemic control and the outcomes of KT in patients with diabetic nephropathy.

METHODS

We conducted a retrospective chart review of kidney transplant recipients (KTRs) with diabetic nephropathy from three tertiary hospitals to analyze the association between post-transplant glycemic control and the clinical outcomes of graft failure, including patient death and biopsy-proven acute rejection (BPAR). We assessed time-averaged glucose level and hemoglobin A1c (HbA1c) for 36 months after KT.

RESULTS

Among 3,538 KTRs, a total of 476 patients received kidney transplantation because of diabetic nephropathy. Mean time-averaged glucose and HbA1c levels were 147 ± 46 mg/dl and 7.7 ± 1.5%, respectively. Patients with diabetic nephropathy had poor graft and patient survival rate compared with non-diabetic nephropathy. Among KTRs with diabetic nephropathy, the highest quartile of time-averaged glucose was related to poor graft outcomes and the 3rd quartile of time-averaged HbA1c was associated with significantly better graft outcomes than the 1st, 2nd or 4th quartiles. There were no significant differences in the risk of BPAR across the 4 quartiles of glucose and HbA1c.

CONCLUSIONS

Strict glycemic control before KT might not be related to successful outcomes but poor glycemic control after KT is associated with poor graft outcomes. There was no significant relationship between pre- or post-transplant glycemic control and BPAR.

Metabolomic Profiling in Individuals with a Failing Kidney Allograft

BACKGROUND

Alteration of certain metabolites may play a role in the pathophysiology of renal allograft disease.

METHODS

To explore metabolomic abnormalities in individuals with a failing kidney allograft, we analyzed by liquid chromatography-mass spectrometry (LC-MS/MS; for ex vivo profiling of serum and urine) and two dimensional correlated spectroscopy (2D COSY; for in vivo study of the kidney graft) 40 subjects with varying degrees of chronic allograft dysfunction stratified by tertiles of glomerular filtration rate (GFR; T1, T2, T3). Ten healthy non-allograft individuals were chosen as controls.

RESULTS

LC-MS/MS analysis revealed a dose-response association between GFR and serum concentration of tryptophan, glutamine, dimethylarginine isomers (asymmetric [A]DMA and symmetric [S]DMA) and short-chain acylcarnitines (C4 and C12), (test for trend: T1-T3 = p<0.05; p = 0.01; p<0.001; p = 0.01; p = 0.01; p<0.05, respectively). The same association was found between GFR and urinary levels of histidine, DOPA, dopamine, carnosine, SDMA and ADMA (test for trend: T1-T3 = p<0.05; p<0.01; p = 0.001; p<0.05; p = 0.001; p<0.001; p<0.01, respectively). In vivo 2D COSY of the kidney allograft revealed significant reduction in the parenchymal content of choline, creatine, taurine and threonine (all: p<0.05) in individuals with lower GFR levels.

CONCLUSIONS

We report an association between renal function and altered metabolomic profile in renal transplant individuals with different degrees of kidney graft function.

Insight into microenvironment remodeling in pancreatic endocrine tissue engineering: Biological and biomaterial approaches

The treatment of diabetes mellitus, as a chronic and complicated disease, is a valuable purpose. Islet transplantation can provide metabolic stability and insulin independence in type 1 diabetes patients. Diet and insulin therapy are only diabetes controllers and cannot remove all of the diabetes complications. Moreover, islet transplantation is more promising treatment than whole pancreas transplantation because of lesser invasive surgical procedure and morbidity and mortality. According to the importance of extracellular matrix for islet viability and function, microenvironment remodeling of pancreatic endocrine tissue can lead to more success in diabetes treatment by pancreatic islets. Production of bioengineered pancreas and remodeling of pancreas extracellular matrix provide essential microenvironment for re-vascularization, re-innervation and signaling cascades triggering. Therefore, islets show better viability and function in these conditions. Researchers conduct various scaffolds with different biomaterials for the improvement of islet viability, function and transplantation outcome. The attention to normal pancreas anatomy, embryology and histology is critical to understand the pancreatic Langerhans islets niche and finally to achieve efficient engineered structure. Therefore, in the present study, the status and components of the islets niche is mentioned and fundamental issues related to the tissue engineering of this structure is considered. The purpose of this review article is summarization of recent progress in the endocrine pancreas tissue engineering and biomaterials and biological aspects of it.

Type 1 Diabetes and Dysfunctional Intestinal Homeostasis

Despite the relatively high frequency of gastrointestinal (GI) disorders in individuals with type 1 diabetes (T1D), termed diabetic enteropathy (DE), the pathogenic mechanisms of these disorders remain to be elucidated. While previous studies have assumed that DE is a manifestation of diabetic autonomic neuropathy, other contributing factors such as enteric hormones, inflammation, and microbiota were later recognized. More recently, the emerging role of intestinal stem cells (ISCs) in several GI diseases has led to a new understanding of DE. Given the absence of diagnostic methods and the lack of broadly efficacious therapeutic remedies in DE, targeting factors and pathways that control ISC homeostasis and are dysfunctional in DE may represent a new path for the detection and cure of DE.

Clinical Efficacy of Stem Cell Therapy for Diabetes Mellitus: A Meta-Analysis

BACKGROUND

Stem cell therapy is a promising therapeutic modality for advanced diabetes mellitus (DM). This study presents a meta-analysis of relevant clinical trials to determine the efficacy of stem cell therapy in DM. We aim to critically evaluate and synthesize clinical evidence on the safety and efficiency of different types of stem cell therapy for both T1DM and T2DM.

METHODS AND FINDINGS

We pooled participant-level data from twenty-two eligible clinical trials that satisfied our inclusion criteria, with a total of 524 patients. There were significant differences in the outcome based on the type and source of the infused cells. Out of all T1DM patients who received CD34+ hematopoietic stem cell (HSC) infusion, 58.9% became insulin independent for a mean period of 16 months, whereas the results were uniformly negative in patients who received umbilical cord blood (UCB). Infusion of umbilical cord mesenchymal stem cells (UC-MSCs) provided significantly beneficial outcome in T1DM, when compared to bone-marrow mesenchymal stem cells (BM-MSCs) (P<0.0001 and P = 0.1557). Administration of stem cell therapy early after DM diagnosis was more effective than intervention at later stages (relative risk = 2.0, P = 0.0008). Adverse effects were observed in only 21.72% of both T1DM and T2DM stem cell recipients with no reported mortality. Out of all poor responders, 79.5% were diagnosed with diabetic ketoacidosis.

CONCLUSIONS

Stem cell transplantation can represent a safe and effective treatment for selected patients with DM. In this cohort of trials, the best therapeutic outcome was achieved with CD34+ HSC therapy for T1DM, while the poorest outcome was observed with HUCB for T1DM. Diabetic ketoacidosis impedes therapeutic efficacy.

Beta-cell replacement therapy: current outcomes and future landscape

PURPOSE OF REVIEW

This article provides a summary of the current outcomes of β-cell replacement strategies, an algorithm for choosing a specific modality while highlighting associated advantages and disadvantages, and outlines remaining challenges and areas of active investigation in β-cell replacement therapy.

RECENT FINDINGS

The most recent reports of islet cell allotransplantation have shown improvements over previous eras and now rival some outcomes of pancreas alone transplantation. Active areas of investigation are focused on improving techniques for islet isolation, graft monitoring, and managing challenges posed by the innate and alloimmune systems.

SUMMARY

Patients with insulin-dependent diabetes who continue to experience life threatening hypoglycemia despite maximal medical management can benefit from β-cell replacement. Emerging nontransplant technologies have not provided a physiologic euglycemic state to the extent offered by transplantation. Islet transplantation eliminates hypoglycemic episodes/unawareness, facilitates normalization of hemoglobin A1c (HbA1c), decreases microvascular disease progression, and improves quality of life for patients with problematic diabetes. Mid- and long-term outcomes of islet transplantation performed at expert centers approximate those of registry reports of solitary pancreas transplant, whereas the complication profile is quite favorable.

Regenerative Therapy of Type 1 Diabetes Mellitus: From Pancreatic Islet Transplantation to Mesenchymal Stem Cells

Type 1 diabetes is an autoimmune disease resulting in the permanent destruction of pancreatic islets. Islet transplantation to portal vein provides an approach to compensate for loss of insulin producing cells. Clinical trials demonstrated that even partial islet graft function reduces severe hypoglycemic events in patients. However, therapeutic impact is restrained due to shortage of pancreas organ donors and instant inflammation occurring in the hepatic environment of the graft. We summarize on what is known about regenerative therapy in type 1 diabetes focusing on pancreatic islet transplantation and new avenues of cell substitution. Metabolic pathways and energy production of transplanted cells are required to be balanced and protection from inflammation in their intravascular bed is desired. Mesenchymal stem cells (MSCs) have anti-inflammatory features, and so they are interesting as a therapy for type 1 diabetes. Recently, they were reported to reduce hyperglycemia in diabetic rodents, and they were even discussed as being turned into endodermal or pancreatic progenitor cells. MSCs are recognized to meet the demand of an individual therapy not raising the concerns of embryonic or induced pluripotent stem cells for therapy.

Co-transplantation of autologous MSCs delays islet allograft rejection and generates a local immunoprivileged site

AIMS

Mesenchymal stem cells (MSCs) are multipotent cells with immunomodulatory properties. We tested the ability of MSCs to delay islet allograft rejection.

METHODS

Mesenchymal stem cells were generated in vitro from C57BL/6 and BALB/c mice bone marrow, and their immunomodulatory properties were tested in vitro. We then tested the effect of a local or systemic administration of heterologous and autologous MSCs on graft survival in a fully allogeneic model of islet transplantation (BALB/c islets into C57BL/6 mice).

RESULTS

In vitro, autologous, but not heterologous, MSCs abrogated immune cell proliferation in response to alloantigens and skewed the immune response toward a Th2 profile. A single dose of autologous MSCs co-transplanted under the kidney capsule with allogeneic islets delayed islet rejection, reduced graft infiltration, and induced long-term graft function in 30 % of recipients. Based on ex vivo analysis of recipient splenocytes, the use of autologous MSCs did not appear to have any systemic effect on the immune response toward graft alloantigens. The systemic injection of autologous MSCs or the local injection of heterologous MSCs failed to delay islet graft rejection.

CONCLUSION

Autologous, but not heterologous, MSCs showed multiple immunoregulatory properties in vitro and delayed allograft rejection in vivo when co-transplanted with islets; however, they failed to prevent rejection when injected systemically. Autologous MSCs thus appear to produce a local immunoprivileged site, which promotes graft survival.

Pancreas Islet Transplantation for Patients With Type 1 Diabetes Mellitus: A Clinical Evidence Review

BACKGROUND

Type 1 diabetes mellitus is caused by the autoimmune destruction of pancreatic beta (β) cells, resulting in severe insulin deficiency. Islet transplantation is a β-cell replacement therapeutic option that aims to restore glycemic control in patients with type 1 diabetes. The objective of this study was to determine the clinical effectiveness of islet transplantation in patients with type 1 diabetes, with or without kidney disease.

METHODS

We conducted a systematic review of the literature on islet transplantation for type 1 diabetes, including relevant health technology assessments, systematic reviews, meta-analyses, and observational studies. We used a two-step process: first, we searched for systematic reviews and health technology assessments; second, we searched primary studies to update the chosen health technology assessment. The Assessment of Multiple Systematic Reviews measurement tool was used to examine the methodological quality of the systematic reviews and health technology assessments. We assessed the quality of the body of evidence and the risk of bias according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria.

RESULTS

Our searched yielded 1,354 citations. One health technology assessment, 11 additional observational studies to update the health technology assessment, one registry report, and four guidelines were included; the observational studies examined islet transplantation alone, islet-after-kidney transplantation, and simultaneous islet-kidney transplantation. In general, low to very low quality of evidence exists for islet transplantation in patients with type 1 diabetes with difficult-to-control blood glucose levels, with or without kidney disease, for these outcomes: health-related quality of life, secondary complications of diabetes, glycemic control, and adverse events. However, high quality of evidence exists for the specific glycemic control outcome of insulin independence compared with intensive insulin therapy. For patients without kidney disease, islet transplantation improves glycemic control and diabetic complications for patients with type 1 diabetes when compared with intensive insulin therapy. However, results for health-related quality of life outcomes were mixed, and adverse events were increased compared with intensive insulin therapy. For patients with type 1 diabetes with kidney disease, islet-after-kidney transplantation or simultaneous islet-kidney transplantation also improved glycemic control and secondary diabetic complications, although the evidence was more limited for this patient group. Compared with intensive insulin therapy, adverse events for islet-after-kidney transplantation or simultaneous islet-kidney transplantation were increased, but were in general less severe than with whole pancreas transplantation.

CONCLUSIONS

For patients with type 1 diabetes with difficult-to-control blood glucose levels, islet transplantation may be a beneficial β-cell replacement therapy to improve glycemic control and secondary complications of diabetes. However, there is uncertainty in the estimates of effectiveness because of the generally low to very low quality of evidence for all outcomes of interest.

The beneficial effect of growth hormone treatment on islet mass in streptozotocin-treated mice

BACKGROUND

Type 1 diabetes is an autoimmune disease, characterized by a loss of pancreatic β-cell mass and function, which results in dramatic reductions in insulin secretion and circulating insulin levels. Patients with type 1 diabetes are traditionally treated with insulin injections and insulin pumps ex vivo or undergo transplantation. Growth hormone (GH) has been shown to be involved in β-cell function and survival in culture.

METHODS

Twelve-week-old female C57BL/6 mice were treated with streptozotocin and monitored for their weight and blood glucose levels. Fourteen days post-initial injection, these mice were separated into two groups at random. One group was treated with GH while the other treated with vehicle for up to 3 weeks. These mice were compared with mice not treated with streptozotocin.

RESULTS

Under our experimental conditions, we observed that mice treated with GH had larger islets and higher serum insulin levels than streptozotocin-treated mice treated with saline (0.288 vs. 0.073 ng/mL, p < 0.01).

CONCLUSIONS

Our data demonstrate that GH may rescue islets and therefore may possess therapeutic potential in the treatment of type 1 diabetes, although consideration should be made regarding GH's effect on insulin resistance.

Clinical results of islet transplantation

Islet transplantation is considered an advanced therapy in the treatment of type-1 diabetes, with a progressive improvement of clinical results as seen in the Collaborative Islet Transplant Registry (CITR) report. It is an accepted method for the stabilization of frequent hypoglycemia, or severe glycemic lability, in patients with hypoglycemic unawareness, poor diabetic control, or a resistance to intensive insulin-based therapies. Worldwide data confirm a positive trend in this field, with the integrated management of pivotal factors: adequate islet mass, immunosuppressive protocols, additional anti-inflammatory therapy, and pre-transplant allo-immunity assessment. Insulin independence has been observed in several clinical trials with different rate, ranging 100-65% of patients; the maintenance of this condition during the follow-up progressively decreased, actually arranged on 44% 3 years after the last infusion, according to data reported from the CITR. Successful duration is progressively increasing, with ≥13 years being the longest reported insulin-free condition on record. The immediate results of functioning islet transplantation are an improvement in hypoglycemic awareness and a reduction in the glycated hemoglobin level. Furthermore, many studies have shown its influence on the chronic complications of diabetes, such as peripheral neuropathy, retinopathy, and macroangiopathy. Pre-transplant nephropathy remains an exclusion criterion as immunosuppressive therapy can exacerbate kidney-function deterioration. The problems linked to immunosuppression following islet transplantation for the treatment of type-1 diabetes need to be considered in order to achieve the correct risk/benefit ratio for each patient.

Pancreas and islet transplantation: psychological themes pre- and posttransplant

PURPOSE OF REVIEW

To date, islet and whole pancreas transplantation have been largely researched and reported separately. Therefore, for the first time, this review seeks to examine together the recently reported psychological issues as they relate to the two different types of transplantation.

RECENT FINDINGS

In relation to pancreas transplantation, recent findings indicate potential issues relating to energy levels, including sleep problems; mood problems (anxiety, depression, traumatic stress); social interactions; and identity issues. Similarly, the research on islet allotransplantation (ITA) indicates mood disruptions associated with Type I diabetes mellitus (T1DM), which seem to improve as a result of treatment with ITA.

SUMMARY

The review indicates a need for more research to guide effective intervention to optimize psychological recovery post islet and/or pancreas transplantation for patients with T1DM. Effective psychological intervention for this group relies on researchers eliciting more detailed knowledge of pretransplant psychosocial issues, not only in relation to how these might vary by transplant group, but also in relation to patient health status vis-à-vis microvascular complications and glycaemic control, and how these issues change across the whole transplant journey.

Type 1 Diabetes Modifies Brain Activation in Young Patients While Performing Visuospatial Working Memory Tasks

In recent years, increasing attention has been paid to the effects of Type 1 Diabetes (T1D) on cognitive functions. T1D onset usually occurs during childhood, so it is possible that the brain could be affected during neurodevelopment. We selected young patients of normal intelligence with T1D onset during neurodevelopment, no complications from diabetes, and adequate glycemic control. The purpose of this study was to compare the neural BOLD activation pattern in a group of patients with T1D versus healthy control subjects while performing a visuospatial working memory task. Sixteen patients and 16 matched healthy control subjects participated. There was no significant statistical difference in behavioral performance between the groups, but, in accordance with our hypothesis, results showed distinct brain activation patterns. Control subjects presented the expected activations related to the task, whereas the patients had greater activation in the prefrontal inferior cortex, basal ganglia, posterior cerebellum, and substantia nigra. These different patterns could be due to compensation mechanisms that allow them to maintain a behavioral performance similar to that of control subjects.

Novel therapeutic approaches for diabetic nephropathy and retinopathy

Diabetes mellitus is a chronic disease that in the long-term increases the microvascular and macrovascular degenerative complications thus being responsible for a large part of death associated with diabetes. During the years, while preventive care for diabetic patients has improved, the increase in the prevalence of diabetes worldwide is continuous. The detrimental effects of diabetes mellitus result in microvascular diseases, which recognize hyperglycemia as major determinant. A significant number of potential therapeutic targets for the treatment of diabetic microvascular complications have been proposed, but the encouraging results obtained in preclinical studies, have largely failed in clinical trials. Currently, the most successful strategy to prevent microvascular complications of diabetes is the intensive treatment of hyperglycemia or the normalization of glycometabolic control achieved with pancreatic and islet transplantation. In this review, we focus on the novel therapeutic targets to prevent the development and progression of diabetic nephropathy and retinopathy microvascular complications.

Autologous nonmyeloablative hematopoietic stem cell transplantation in new-onset type 1 diabetes: a multicenter analysis

Type 1 diabetes (T1D) is one of the major autoimmune diseases affecting children and young adults worldwide. To date, the different immunotherapies tested have achieved insulin independence in <5% of treated individuals. Recently, a novel hematopoietic stem cell (HSC)-based strategy has been tested in individuals with new-onset T1D. The aim of this study was to determine the effects of autologous nonmyeloablative HSC transplantation in 65 individuals with new-onset T1D who were enrolled in two Chinese centers and one Polish center, pooled, and followed up for 48 months. A total of 59% of individuals with T1D achieved insulin independence within the first 6 months after receiving conditioning immunosuppression therapy (with antithymocyte globulin and cyclophosphamide) and a single infusion of autologous HSCs, and 32% remained insulin independent at the last time point of their follow-up. All treated subjects showed a decrease in HbA1c levels and an increase in C-peptide levels compared with pretreatment. Despite a complete immune system recovery (i.e., leukocyte count) after treatment, 52% of treated individuals experienced adverse effects. Our study suggests the following: 1) that remission of T1D is possible by combining HSC transplantation and immunosuppression; 2) that autologous nonmyeloablative HSC transplantation represents an effective treatment for selected individuals with T1D; and 3) that safer HSC-based therapeutic options are required.