β-Cell regeneration through the transdifferentiation of pancreatic cells: Pancreatic progenitor cells in the pancreas

Among Other Tissues, Short-Term Garlic Oral Treatment Incrementally Improves Indicants of Only Pancreatic Islets of Langerhans Histology and Insulin mRNA Transcription and Synthesis in Diabetic Rats

BACKGROUND

The source, mRNA transcription, and synthesis of insulin in the pancreas, in addition to the bile duct and liver, in streptozotocin (STZ)-induced diabetic rats (DR) in response to garlic oral treatment are not yet clear.

OBJECTIVE

This study investigated the accumulative effects of continued garlic oral treatment on changes in the pancreas, bile duct, and liver with regards to: 1-Insulin mRNA transcription, synthesis, and concentration in relation to changes in serum insulin (SI); 2-Insulinogenic cells insulin intensity and distribution, proliferation, and morphology.

METHOD

Fasting blood glucose (FBG) and insulin concentration in serum and pancreas (PI) and sources and mRNA transcription in the pancreas, bile duct, and liver in normal rats given normal saline (NR-NS) and DR given either NS (DR-NS) or garlic extract (DR-GE) before and after 1, 4, and 8 weeks of oral treatment were examined.

RESULTS

Compared to NR-NS, DR-NS showed a significant increase in FBG and reductions in SI and PI and deterioration in islets histology, associated pancreatic insulin numerical intensities, and mRNA transcription. However, compared to DR-NS, the targeted biochemical, histological, and genetic variables of DR-GE were significantly and incrementally improved as garlic treatment continued. Insulin or its indicators were not detected either in the bile duct or the liver in DR-GE.

CONCLUSIONS

8 weeks of garlic oral treatment is enough to incrementally restore only pancreatic islets of Langerhans insulin intensity and insulinogenic cells proliferation, morphology, and distribution. These indices were associated with enhanced pancreatic insulin mRNA transcription and synthesis. Eight weeks of garlic treatment were not enough to stimulate insulinogenesis in either the bile duct or the liver.

Therapeutic approaches for Type 1 Diabetes: Promising cell-based approaches to achieve ultimate success

Type 1 Diabetes mellitus (T1DM) is a chronic metabolic disorder characterized by pancreatic β-cells destruction. Despite substantial advances in T1DM treatment, lifelong exogenous insulin administration is the mainstay of treatments, and constant control of glucose levels is still a challenge. Endogenous insulin production by replacing insulin-producing cells is an alternative, but the lack of suitable donors is accounted as one of the main obstacles to its widespread application. The research and trials overview demonstrates that endogenous production of insulin has started to go beyond the deceased-derived to stem cells-derived insulin-producing cells. Several protocols have been developed over the past couple of years for generating insulin-producing cells (IPCs) from various stem cell types and reprogramming fully differentiated cells. A straightforward and quick method for achieving this goal is to investigate and apply the β-cell specific transcription factors as a direct strategy for IPCs generation. In this review, we emphasize the significance of transcription factors in IPCs development from different non-beta cell sources, and pertinent research underlies the marked progress in the methods for generating insulin-producing cells and application for Type 1 Diabetes treatment.

NEUROD1 reinforces endocrine cell fate acquisition in pancreatic development

NEUROD1 is a transcription factor that helps maintain a mature phenotype of pancreatic β cells. Disruption of Neurod1 during pancreatic development causes severe neonatal diabetes; however, the exact role of NEUROD1 in the differentiation programs of endocrine cells is unknown. Here, we report a crucial role of the NEUROD1 regulatory network in endocrine lineage commitment and differentiation. Mechanistically, transcriptome and chromatin landscape analyses demonstrate that Neurod1 inactivation triggers a downregulation of endocrine differentiation transcription factors and upregulation of non-endocrine genes within the Neurod1-deficient endocrine cell population, disturbing endocrine identity acquisition. Neurod1 deficiency altered the H3K27me3 histone modification pattern in promoter regions of differentially expressed genes, which resulted in gene regulatory network changes in the differentiation pathway of endocrine cells, compromising endocrine cell potential, differentiation, and functional properties.

Biomedical importance of the ubiquitin-proteasome system in diabetes and metabolic transdifferentiation of pancreatic duct epithelial cells into β-cells

The ubiquitin-proteasome system (UPS) is a major pathway for cellular protein degradation. The molecular function of the UPS is the removal of damaged proteins, and this function is applied in many biological processes, including inflammation, proliferation, and apoptosis. Accumulating evidence also suggests that the UPS also has a key role in pancreatic β-cell transdifferentiation in diabetes and can be targeted for treatment of diabetic diseases. In this review, we summarized the mechanistic roles of the UPS in the biochemical activities of pancreatic β-cells, including the role of the UPS in insulin synthesis and secretion, as well as β-cell degradation. Also, we discuss how the UPS mediates the transdifferentiation of pancreatic duct epithelial cells into β-cells as the experimental basis for the development of new strategies for the treatment of diabetes in regenerative medicine.

Nutritional strategies for intervention of diabetes and improvement of β-cell function

Diabetes mellitus, especially Type 2 diabetes (T2D), is caused by multiple factors including genetics, diets, and lifestyles. Diabetes is a chronic condition and is among the top 10 causes of death globally. Nutritional intervention is one of the most important and effective strategies for T2D management. It is well known that most of intervention strategies can lower blood glucose level and improve insulin sensitivity in peripheral tissues. However, the regulation of pancreatic β cells by dietary intervention is not well characterized. In this review, we summarized some of the commonly used nutritional methods for diabetes intervention. We then discussed the effects and the underlying mechanisms of nutritional intervention in improving the cell mass and function of pancreatic islet β cells. With emerging intervention strategies and in-depth investigation, we are expecting to have a better understanding about the effectiveness of dietary interventions in ameliorating T2D in the future.

A randomized trial of oral gamma aminobutyric acid (GABA) or the combination of GABA with glutamic acid decarboxylase (GAD) on pancreatic islet endocrine function in children with newly diagnosed type 1 diabetes

Gamma aminobutyric acid(GABA) is synthesized by glutamate decarboxylase(GAD) in β-cells. Regarding Type 1 diabetes(T1D), animal/islet-cell studies found that GABA promotes insulin secretion, inhibits α-cell glucagon and dampens immune inflammation, while GAD immunization may also preserve β-cells. We evaluated the safety and efficacy of oral GABA alone, or combination GABA with GAD, on the preservation of residual insulin secretion in recent-onset T1D. Herein we report a single-center, double-blind, one-year, randomized trial in 97 children conducted March 2015 to June 2019(NCT02002130). Using a 2:1 treatment:placebo ratio, interventions included oral GABA twice-daily(n = 41), or oral GABA plus two-doses GAD-alum(n = 25), versus placebo(n = 31). The primary outcome, preservation of fasting/meal-stimulated c-peptide, was not attained. Of the secondary outcomes, the combination GABA/GAD reduced fasting and meal-stimulated serum glucagon, while the safety/tolerability of GABA was confirmed. There were no clinically significant differences in glycemic control or diabetes antibody titers. Given the low GABA dose for this pediatric trial, future investigations using higher-dose or long-acting GABA formulations, either alone or with GAD-alum, could be considered, although GABA alone or in combination with GAD-alum did nor preserve beta-cell function in this trial.

Gymnemic Acid Ameliorates Pancreatic β-Cell Dysfunction by Modulating Pdx1 Expression: A Possible Strategy for β-Cell Regeneration

BACKGROUND

Endogenous pancreatic β-cell regeneration is a promising therapeutic approach for enhancing β-cell function and neogenesis in diabetes. Various findings have reported that regeneration might occur via stimulating β-cell proliferation, neogenesis, or conversion from other pancreatic cells to β-like cells. Although the current scenario illustrates numerous therapeutic strategies and approaches that concern endogenous β-cell regeneration, all of them have not been successful to a greater extent because of cost effectiveness, availability of suitable donors and rejection in case of transplantation, or lack of scientific evidence for many phytochemicals derived from plants that have been employed in traditional medicine. Therefore, the present study aims to investigate the effect of gymnemic acid (GA) on β-cell regeneration in streptozotocin-induced type 1 diabetic rats and high glucose exposed RIN5-F cells.

METHODS

The study involves histopathological and immunohistochemical analysis to examine the islet's architecture. Quantitative polymerase chain reaction (qPCR) and/or immunoblot were employed to quantify the β-cell regeneration markers and cell cycle proliferative markers.

RESULTS

The immunoexpression of E-cadherin, β-catenin, and phosphoinositide 3-kinases/protein kinase B were significantly increased in GA-treated diabetic rats. On the other hand, treatment with GA upregulated the pancreatic regenerative transcription factor viz. pancreatic duodenal homeobox 1, Neurogenin 3, MafA, NeuroD1, and β-cells proliferative markers such as CDK4, and Cyclin D1, with a simultaneous downregulation of the forkhead box O, glycogen synthase kinase-3, and p21^cip1 in diabetic treated rats. Adding to this, we noticed increased nuclear localization of Pdx1 in GA treated high glucose exposed RIN5-F cells.

CONCLUSION

Our results suggested that GA acts as a potential therapeutic candidate for endogenous β-cell regeneration in treating type 1 diabetes.

Crosstalk Communications Between Islets Cells and Insulin Target Tissue: The Hidden Face of Iceberg

The regulation of insulin secretion is under control of a complex inter-organ/cells crosstalk involving various metabolites and/or physical connections. In this review, we try to illustrate with current knowledge how β-cells communicate with other cell types and organs in physiological and pathological contexts. Moreover, this review will provide a better understanding of the microenvironment and of the context in which β-cells exist and how this can influence their survival and function. Recent studies showed that β-cell insulin secretion is regulated also by a direct and indirect inter-organ/inter-cellular communication involving various factors, illustrating the idea of "the hidden face of the iceberg". Moreover, any disruption on the physiological communication between β-cells and other cells or organs can participate on diabetes onset. Therefore, for new anti-diabetic treatments' development, it is necessary to consider the entire network of cells and organs involved in the regulation of β-cellular function and no longer just β-cell or pancreatic islet alone. In this context, we discuss here the intra-islet communication, the β-cell/skeletal muscle, β-cell/adipose tissue and β-cell/liver cross talk.

Emerging Treatment Strategies for Diabetes Mellitus and Associated Complications: An Update

The occurrence of diabetes mellitus (DM) is increasing rapidly at an accelerating rate worldwide. The status of diabetes has changed over the last three generations; whereas before it was deemed a minor disease of older people but currently it is now one of the leading causes of morbidity and mortality among middle-aged and young people. High blood glucose-mediated functional loss, insulin sensitivity, and insulin deficiency lead to chronic disorders such as Type 1 and Type 2 DM. Traditional treatments of DM, such as insulin sensitization and insulin secretion cause undesirable side effects, leading to patient incompliance and lack of treatment. Nanotechnology in diabetes studies has encouraged the development of new modalities for measuring glucose and supplying insulin that hold the potential to improve the quality of life of diabetics. Other therapies, such as β-cells regeneration and gene therapy, in addition to insulin and oral hypoglycemic drugs, are currently used to control diabetes. The present review highlights the nanocarrier-based drug delivery systems and emerging treatment strategies of DM.

Tissue Engineering Strategies for Improving Beta Cell Transplantation Outcome

Purpose of Review

Beta cell replacement therapy as a form of islet transplantation is a promising alternative therapy with the possibility to make selected patients with type 1 diabetes (T1D) insulin independent. However, this technique faces challenges such as extensive activation of the host immune system post-transplantation, lifelong need for immunosuppression, and the scarcity of islet donor pancreas. Advancement in tissue engineering strategies can improve these challenges and allow for a more widespread application of this therapy. This review will discuss the recent development and clinical translation of tissue engineering strategies in beta cell replacement therapy.

Recent Findings

Tissue engineering offers innovative solutions for producing unlimited glucose responsive cells and fabrication of appropriate devices/scaffolds for transplantation applications. Generation of pancreatic organoids with supporting cells in biocompatible biomaterials is a powerful technique to improve the function of insulin-producing cell clusters. Fabrication of physical barriers such as encapsulation strategies can protect the cells from the host immune system and allow for graft retrieval, although this strategy still faces major challenges to fully restore physiological glucose regulation.

Summary

The three main components of tissue engineering strategies including the generation of stem cell-derived insulin-producing cells and organoids and the possibilities for therapeutic delivery of cell-seeded devices to extra-hepatic sites need to come together in order to provide safe and functional insulin-producing devices for clinical beta cell replacement therapy.

Single-cell transcriptome analysis defines heterogeneity of the murine pancreatic ductal tree

To study disease development, an inventory of an organ's cell types and understanding of physiologic function is paramount. Here, we performed single-cell RNA-sequencing to examine heterogeneity of murine pancreatic duct cells, pancreatobiliary cells, and intrapancreatic bile duct cells. We describe an epithelial-mesenchymal transitory axis in our three pancreatic duct subpopulations and identify osteopontin as a regulator of this fate decision as well as human duct cell dedifferentiation. Our results further identify functional heterogeneity within pancreatic duct subpopulations by elucidating a role for geminin in accumulation of DNA damage in the setting of chronic pancreatitis. Our findings implicate diverse functional roles for subpopulations of pancreatic duct cells in maintenance of duct cell identity and disease progression and establish a comprehensive road map of murine pancreatic duct cell, pancreatobiliary cell, and intrapancreatic bile duct cell homeostasis.

A new hypothetical model for pancreatic development based on change in the cell division orientation

Although lifelong renewal and additional compensatory growth in response to demand are undeniable facts, so far, no specific stem cells have been found for pancreatic cells. According to the consensus model, the development of pancreas results from the hierarchical differentiation of pluripotent stem cells towards the appearance of the first endocrine and exocrine cells at approximately 7.5 to 8th gestation week (GW) of human embryo. However, the primitive endocrine cells arising from the embryonic phase of development do not appear to be mature or fully functional. Asymmetric localization of cellular components, such as Numb, partition protein complexes (PAR), planar cell polarity components, and certain mRNAs on the apical and basal sides of epithelial cells, causes cellular polarization. According to our model, the equal distribution of cellular components during symmetric cell division yields similar daughter cells that are associated with duct expansion. In contrast, asymmetric cell division is associated with uneven distribution of cellular components among daughter cells, resulting in different fates. Asymmetric cell division leads to duct branching and the development of acinar and stellate cells by a daughter cell, as well as the development of islet progenitor cells through partial epithelial-to-mesenchymal transition (EMT) and delamination of another daughter cell. Recently, we have developed an efficient method to obtain insulin-secreting cells from the transdifferentiation of hESC-derived ductal cells inducing a partial EMT by treatment with Wnt3A and activin A in a hypoxic environment. Similar models can be offered for other tissues and organs such as mammary glands, lungs, prostate, liver, etc. This model may open a new horizon in the field of regenerative medicine and be useful in explaining the cause of certain abnormalities, such as the occurrence of certain cysts and tumors.

Advancements in transplantation therapy for diabetes: Pancreas, islet and stem cell

Pancreas transplantation and islet transplantation are now established in the treatment of IDDM. Several trials of stem cell-derived cell transplantation therapy are underway and may offer an alternative to the limited supply of donor islets in the near future. This article summarizes recent developments in transplantation therapy for diabetes as well as research on the use of stem cells for complications of diabetes.

Transdifferentiation of both intra- and extra-islet cells into beta cells in nicotinamide treated neonatal diabetic rats: An in situ hybridization and double immunohistochemical study

We aimed to study the effect of nicotinamide (NA) on beta (β)-cell regeneration and apoptosis in streptozotocin induced neonatal rats (n-STZ). Three groups were performed: Control group, n2-STZ group (100 mg/kg STZ on the second day-after birth), n2-STZ + NA group (STZ;100 mg/kg + NA;500 mg/kg/day for 5 days). The pancreatic tissue sections were immunostained with insulin, glucagon, somatostatin, Pdx1, Notch1 and active caspase-3 antibodies, and double immunostained with insulin/PCNA, insulin/glucagon and insulin/somatostatin antibodies. In situ hybridization carried out with insulin probe. Apoptotic β-cell were shown by TUNEL assay, followed by immunostaining. The number of insulin/PCNA, insulin/glucagon and insulin/somatostatin double-positive cells significantly increased in n2-STZ + NA group compared with the other groups (p < 0.001). n2- STZ group had lower number of insulin and Pdx1 positive cells in islets, compared to NA treated diabetics. The insulin and Pdx1 immun positive cells were located in the small clusters or scattered through the exocrine tissue and around to ducts in n2-STZ + NA group. Notch1 positive cell numbers were increased, whereas caspase-3 and TUNEL positive β-cell numbers were decreased in n2-STZ + NA group. NA treatment induces the neogenic insulin positive islets orginated from the differentiation of ductal progenitor cells, transdifferentiation of acinar cells into β cells, and transformation of potent precursor cells and centroacinar cells via the activated Notch expression into β-cells in n-STZ rats.

β-Cell specific transcription factors in the context of diabetes mellitus and β-cell regeneration

All pancreatic cell populations arise from the standard gut endoderm layer in developing embryos, requiring a regulatory gene network to originate and maintain endocrine lineages and endocrine function. The pancreatic organogenesis is regulated by the temporal expression of transcription factors and plays a diverse role in the specification, development, differentiation, maturation, and functional maintenance. Altered expression and activity of these transcription factors are often associated with diabetes mellitus. Recent advancements in the stem cells and invitro derived islets to treat diabetes mellitus has attracted a great deal of interest in the understanding of factors regulating the development, differentiation, and functions of islets including transcription factors. This review discusses the myriad of transcription factors regulating the development of the pancreas, differentiation of β-islets, and how these factors regulated in normal and disease states. Exploring these factors in such critical context and exogenous or endogenous expression of development and differentiation-specific transcription factors with improved epigenetic plasticity/signaling axis in diabetic milieu would useful for the development of β-cells from other cell sources.

Direct cell reprogramming for tissue engineering and regenerative medicine

Direct cell reprogramming, also called transdifferentiation, allows for the reprogramming of one somatic cell type directly into another, without the need to transition through an induced pluripotent state. Thus, it is an attractive approach to develop novel tissue engineering applications to treat diseases and injuries where there is a shortage of proliferating cells for tissue repair. In certain tissue damage, terminally differentiated somatic cells lose their ability to proliferate, as a result, damaged tissues cannot heal by themselves. Examples of these scenarios include myocardial infarctions, neurodegenerative diseases, and cartilage injuries. Transdifferentiation is capable of reprogramming cells that are abundant in the body into desired cell phenotypes that are able to restore tissue function in damaged areas. Therefore, direct cell reprogramming is a promising direction in the cell and tissue engineering and regenerative medicine fields.

In recent years, several methods for transdifferentiation have been developed, ranging from the overexpression of transcription factors via viral vectors, to small molecules, to clustered regularly interspaced short palindromic repeats (CRISPR) and its associated protein (Cas9) for both genetic and epigenetic reprogramming. Overexpressing transcription factors by use of a lentivirus is currently the most prevalent technique, however it lacks high reprogramming efficiencies and can pose problems when transitioning to human subjects and clinical trials. CRISPR/Cas9, fused with proteins that modulate transcription, has been shown to improve efficiencies greatly. Transdifferentiation has successfully generated many cell phenotypes, including endothelial cells, skeletal myocytes, neuronal cells, and more. These cells have been shown to emulate mature adult cells such that they are able to mimic major functions, and some are capable of promoting regeneration of damaged tissue in vivo. While transdifferentiated cells have not yet seen clinical use, they have had promise in mice models, showing success in treating liver disease and several brain-related diseases, while also being utilized as a cell source for tissue engineered vascular grafts to treat damaged blood vessels. Recently, localized transdifferentiated cells have been generated in situ, allowing for treatments without invasive surgeries and more complete transdifferentiation. In this review, we summarized the recent development in various cell reprogramming techniques, their applications in converting various somatic cells, their uses in tissue regeneration, and the challenges of transitioning to a clinical setting, accompanied with potential solutions.

Type 1 and 2 diabetes mellitus: A review on current treatment approach and gene therapy as potential intervention

Type 1 and type 2 diabetes mellitus is a serious and lifelong condition commonly characterised by abnormally elevated blood glucose levels due to a failure in insulin production or a decrease in insulin sensitivity and function. Over the years, prevalence of diabetes has increased globally and it is classified as one of the leading cause of high mortality and morbidity rate. Furthermore, diabetes confers a huge economic burden due to its management costs as well as its complications are skyrocketing. The conventional medications in diabetes treatment focusing on insulin secretion and insulin sensitisation cause unwanted side effects to patients and lead to incompliance as well as treatment failure. Besides insulin and oral hypoglycaemic agents, other treatments such as gene therapy and induced β-cells regeneration have not been widely introduced to manage diabetes. Therefore, this review aims to deliver an overview of the current conventional medications in diabetes, discovery of newer pharmacological drugs and gene therapy as a potential intervention of diabetes in the future.

MicroRNA-9 modified bone marrow-derived mesenchymal stem cells (BMSCs) repair severe acute pancreatitis (SAP) via inducing angiogenesis in rats

Background

Severe acute pancreatitis (SAP) is an acute abdominal disease characterized by pancreatic necrosis and systemic disease. In a previous study, we showed that bone marrow-derived mesenchymal stem cells (BMSCs) can reduce SAP by secreting microRNA (miR)-9; however, the underlying mechanism remains unclear. The present study investigated the mechanism underlying BMSC-induced pancreatic regeneration.

Methods

BMSCs were isolated, and miR-9 modified/antagonized BMSCs (pri-miR-9-BMSCs/TuD-BMSCs) were generated and injected into SAP rats. The levels of inflammatory cytokines and histopathologic changes were examined using ELISA and H&E staining. Angiogenesis was analyzed by qRT-PCR, western blotting, and immunohistochemistry. Cell function tests, dual luciferase reporter assays, cell co-culture, western blotting, and cell tracing were used to explore the mechanisms underlying miR-9 induced angiogenesis.

Results

Pri-miR-9-BMSCs induced angiogenesis in SAP rats (Ang-1↑, TIE-2↑, and CD31↑) and repaired damaged vascular endothelial cells (VECs) in vitro, promoting angiogenesis (Ang-1↑, TIE-2↑, PI3K↑, AKT↑, p-AKT↑, CD31↑, and CD34↑). Pri-miR-9-BMSCs released miR-9 into VECs or injured pancreatic tissue, targeting the VE-cadherin gene and promoting PI3K/AKT signaling to treat SAP (VE-cadherin↓, β-catenin↓, PI3K↑, p-AKT↑), whereas antagonizing miR-9 in BMSCs did not alleviate or aggravated SAP.

Conclusions

Pri-miR-9-BMSCs can repair injured pancreatic tissue by secreting miR-9 and promoting angiogenesis.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1022-y) contains supplementary material, which is available to authorized users.

Kinetics of pancreatic tissue proliferation in a polymeric platform in mice

BACKGROUND/OBJECTIVES

Pancreas regenerative capacity after injury is not always sufficient to comply with the body's requirement of digestive enzymes and hormones. We present an alternative system to induce pancreas parenchyma proliferation (exocrine and endocrine components), rather than regeneration or remodeling in normoglycemic mice.

METHODS

Porous discs of polyether-polyurethane were surgically placed adjacent to the native pancreas and removed at days 15, 30 and 45 after implantation. No exogenous growth factors or extracellular matrix components were added to the platform. The synthetic matrix provided a platform that was filled with parenchymal and non-parenchymal pancreas tissue as detected by histological analysis. Immunohistochemistry analysis were performed to identify insulin positive cells in the newly formed tissue. In addition, angiogenic, inflammatory and metabolic parameters were carried out in those mice.

RESULTS

At day 15, the pores of the platform were filled with inflammatory cells, spindled-shaped like fibroblasts, extracellular matrix components, blood vessels and clusters of pancreatic parenchyma (acini, ducts and islet-like structures). At days 30 and 45 the pancreas features remained well organized; its organization resembled that of a native pancreas. Interestingly, besides islet-like structures that showed positive cells to insulin, some ductal cells were also positive for insulin immunostaining. No significant differences in serum glucose and c-peptide concentrations during the experimental period were detected.

CONCLUSIONS

The plain synthetic porous platform (without addition of exogenous molecules) placed adjacent to the native organ exhibits potential to restore and/or expand exocrine (acini, ducts) and endocrine (β-cell mass) components in pancreatic injuries and in high metabolic demand.

Role of islet peptides in beta cell regulation and type 2 diabetes therapy

The endocrine pancreas is composed of islets of Langerhans, which secrete a variety of peptide hormones critical for the maintenance of glucose homeostasis. Insulin is the primary regulator of glucose and its secretion from beta-cells is tightly regulated in response to physiological demands. Direct cell-cell communication within islets is essential for glucose-induced insulin secretion. Emerging data suggest that islet connectivity is also important in the regulating the release of other islet hormones including glucagon and somatostatin. Autocrine and paracrine signals exerted by secreted peptides within the islet also play a key role. A great deal of attention has focused on classical islet peptides, namely insulin, glucagon and somatostatin. Recently, it has become clear that islets also synthesise and secrete a range of non-classical peptides, which regulate beta-cell function and insulin release. The current review summarises the roles of islet cell connectivity and islet peptide-driven autocrine and paracrine signalling in beta-cell function and survival. The potential to harness the paracrine effects of non-classical islet peptides for the treatment of type 2 diabetes is also briefly discussed.

Advances in paediatrics in 2016: current practices and challenges in allergy, autoimmune diseases, cardiology, endocrinology, gastroenterology, infectious diseases, neonatology, nephrology, neurology, nutrition, pulmonology

This review reports main progresses in various pediatric issues published in Italian Journal of Pediatrics and in international journals in 2016. New insights in clinical features or complications of several disorders may be useful for our better understanding. They comprise severe asthma, changing features of lupus erythematosus from birth to adolescence, celiac disease, functional gastrointestinal disorders, Moebius syndrome, recurrent pneumonia. Risk factors for congenital heart defects, Kawasaki disease have been widely investigated. New diagnostic tools are available for ascertaining brucellosis, celiac disease and viral infections. The usefulness of aCGH as first-tier test is confirmed in patients with neurodevelopmental disorders. Novel information have been provided on the safety of milk for infants. Recent advances in the treatment of common disorders, including neonatal respiratory distress syndrome, hypo-glycemia in newborns, atopic dermatitis, constipation, cyclic vomiting syndrome, nephrotic syndrome, diabetes mellitus, regurgitation, short stature, secretions in children with cerebral palsy have been reported. Antipyretics treatment has been updated by national guidelines and studies have excluded side effects (e.g. asthma risk during acetaminophen therapy). Vaccinations are a painful event and several options are reported to prevent this pain. Adverse effects due to metabolic abnormalities are reported for second generation antipsychotic drugs.

β-Cell regeneration through the transdifferentiation of pancreatic cells: Pancreatic progenitor cells in the pancreas

Pancreatic progenitor cell research has been in the spotlight, as these cells have the potential to replace pancreatic β‐cells for the treatment of type 1 and 2 diabetic patients with the absence or reduction of pancreatic β‐cells. During the past few decades, the successful treatment of diabetes through transplantation of the whole pancreas or isolated islets has nearly been achieved. However, novel sources of pancreatic islets or insulin‐producing cells are required to provide sufficient amounts of donor tissues. To overcome this limitation, the use of pancreatic progenitor cells is gaining more attention. In particular, pancreatic exocrine cells, such as duct epithelial cells and acinar cells, are attractive candidates for β‐cell regeneration because of their differentiation potential and pancreatic lineage characteristics. It has been assumed that β‐cell neogenesis from pancreatic progenitor cells could occur in pancreatic ducts in the postnatal stage. Several studies have shown that insulin‐producing cells can arise in the duct tissue of the adult pancreas. Acinar cells also might have the potential to differentiate into insulin‐producing cells. The present review summarizes recent progress in research on the transdifferentiation of pancreatic exocrine cells into insulin‐producing cells, especially duct and acinar cells.