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Lansberry TR, Stabler CL. Immunoprotection of cellular transplants for autoimmune type 1 diabetes through local drug delivery. Adv Drug Deliv Rev 2024; 206:115179. [PMID: 38286164 PMCID: PMC11140763 DOI: 10.1016/j.addr.2024.115179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/19/2023] [Accepted: 01/19/2024] [Indexed: 01/31/2024]
Abstract
Type 1 diabetes mellitus (T1DM) is an autoimmune condition that results in the destruction of insulin-secreting β cells of the islets of Langerhans. Allogeneic islet transplantation could be a successful treatment for T1DM; however, it is limited by the need for effective, permanent immunosuppression to prevent graft rejection. Upon transplantation, islets are rejected through non-specific, alloantigen specific, and recurring autoimmune pathways. Immunosuppressive agents used for islet transplantation are generally successful in inhibiting alloantigen rejection, but they are suboptimal in hindering non-specific and autoimmune pathways. In this review, we summarize the challenges with cellular immunological rejection and therapeutics used for islet transplantation. We highlight agents that target these three immune rejection pathways and how to package them for controlled, local delivery via biomaterials. Exploring macro-, micro-, and nano-scale immunomodulatory biomaterial platforms, we summarize their advantages, challenges, and future directions. We hypothesize that understanding their key features will help identify effective platforms to prevent islet graft rejection. Outcomes can further be translated to other cellular therapies beyond T1DM.
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Affiliation(s)
- T R Lansberry
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - C L Stabler
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Department of Immunology and Pathology, College of Medicine, University of Florida, Gainesville, FL, USA; University of Florida Diabetes Institute, Gainesville, FL, USA.
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Hammad SM, Lopes-Virella MF. Circulating Sphingolipids in Insulin Resistance, Diabetes and Associated Complications. Int J Mol Sci 2023; 24:14015. [PMID: 37762318 PMCID: PMC10531201 DOI: 10.3390/ijms241814015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Sphingolipids play an important role in the development of diabetes, both type 1 and type 2 diabetes, as well as in the development of both micro- and macro-vascular complications. Several reviews have been published concerning the role of sphingolipids in diabetes but most of the emphasis has been on the possible mechanisms by which sphingolipids, mainly ceramides, contribute to the development of diabetes. Research on circulating levels of the different classes of sphingolipids in serum and in lipoproteins and their importance as biomarkers to predict not only the development of diabetes but also of its complications has only recently emerged and it is still in its infancy. This review summarizes the previously published literature concerning sphingolipid-mediated mechanisms involved in the development of diabetes and its complications, focusing on how circulating plasma sphingolipid levels and the relative content carried by the different lipoproteins may impact their role as possible biomarkers both in the development of diabetes and mainly in the development of diabetic complications. Further studies in this field may open new therapeutic avenues to prevent or arrest/reduce both the development of diabetes and progression of its complications.
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Affiliation(s)
- Samar M. Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Maria F. Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC 29425, USA
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Gurgul-Convey E. To Be or Not to Be: The Divergent Action and Metabolism of Sphingosine-1 Phosphate in Pancreatic Beta-Cells in Response to Cytokines and Fatty Acids. Int J Mol Sci 2022; 23:ijms23031638. [PMID: 35163559 PMCID: PMC8835924 DOI: 10.3390/ijms23031638] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 01/02/2023] Open
Abstract
Sphingosine-1 phosphate (S1P) is a bioactive sphingolipid with multiple functions conveyed by the activation of cell surface receptors and/or intracellular mediators. A growing body of evidence indicates its important role in pancreatic insulin-secreting beta-cells that are necessary for maintenance of glucose homeostasis. The dysfunction and/or death of beta-cells lead to diabetes development. Diabetes is a serious public health burden with incidence growing rapidly in recent decades. The two major types of diabetes are the autoimmune-mediated type 1 diabetes (T1DM) and the metabolic stress-related type 2 diabetes (T2DM). Despite many differences in the development, both types of diabetes are characterized by chronic hyperglycemia and inflammation. The inflammatory component of diabetes remains under-characterized. Recent years have brought new insights into the possible mechanism involved in the increased inflammatory response, suggesting that environmental factors such as a westernized diet may participate in this process. Dietary lipids, particularly palmitate, are substrates for the biosynthesis of bioactive sphingolipids. Disturbed serum sphingolipid profiles were observed in both T1DM and T2DM patients. Many polymorphisms were identified in genes encoding enzymes of the sphingolipid pathway, including sphingosine kinase 2 (SK2), the S1P generating enzyme which is highly expressed in beta-cells. Proinflammatory cytokines and free fatty acids have been shown to modulate the expression and activity of S1P-generating and S1P-catabolizing enzymes. In this review, the similarities and differences in the action of extracellular and intracellular S1P in beta-cells exposed to cytokines or free fatty acids will be identified and the outlook for future research will be discussed.
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Affiliation(s)
- Ewa Gurgul-Convey
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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4
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Effects of Immunomodulatory Drug Fingolimod (FTY720) on Chlamydia Dissemination and Pathogenesis. Infect Immun 2020; 88:IAI.00281-20. [PMID: 32868341 DOI: 10.1128/iai.00281-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Fingolimod (FTY720), an FDA-approved immunomodulatory drug for treating multiple sclerosis, is an agonist of sphingosine-1-phosphate receptor (S1PR), which has been used as a research tool for inhibiting immune cell trafficking. FTY720 was recently reported to inhibit Chlamydia dissemination. Since genital Chlamydia spreading to the gastrointestinal tract correlated with its pathogenicity in the upper genital tract, we evaluated the effect of FTY720 on chlamydial pathogenicity in the current study. Following an intravaginal inoculation, live chlamydial organisms were detected in mouse rectal swabs. FTY720 treatment significantly delayed live organism shedding in the rectal swabs. However, FTY720 failed to block chlamydial spreading to the gastrointestinal tract. The live chlamydial organisms recovered from rectal swabs reached similar levels between mice with or without FTY720 treatment by day 42 in C57BL/6J and day 28 in CBA/J mice, respectively. Thus, genital Chlamydia is able to launch a 2nd wave of spreading via an FTY720-resistant pathway after the 1st wave of spreading is inhibited by FTY720. As a result, all mice developed significant hydrosalpinx. The FTY720-resistant spreading led to stable colonization of chlamydial organisms in the colon. Consistently, FTY720 did not alter the colonization of intracolonically inoculated Chlamydia Thus, we have demonstrated that, following a delay in chlamydial spreading caused by FTY720, genital Chlamydia is able to both spread to the gastrointestinal tract via an FTY720-resistant pathway and maintain its pathogenicity in the upper genital tract. Further characterization of the FTY720-resistant pathway(s) explored by Chlamydia for spreading to the gastrointestinal tract may promote our understanding of Chlamydia pathogenic mechanisms.
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Sphingolipids in Type 1 Diabetes: Focus on Beta-Cells. Cells 2020; 9:cells9081835. [PMID: 32759843 PMCID: PMC7465050 DOI: 10.3390/cells9081835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/01/2020] [Accepted: 08/03/2020] [Indexed: 12/28/2022] Open
Abstract
Type 1 diabetes (T1DM) is a chronic autoimmune disease, with a strong genetic background, leading to a gradual loss of pancreatic beta-cells, which secrete insulin and control glucose homeostasis. Patients with T1DM require life-long substitution with insulin and are at high risk for development of severe secondary complications. The incidence of T1DM has been continuously growing in the last decades, indicating an important contribution of environmental factors. Accumulating data indicates that sphingolipids may be crucially involved in T1DM development. The serum lipidome of T1DM patients is characterized by significantly altered sphingolipid composition compared to nondiabetic, healthy probands. Recently, several polymorphisms in the genes encoding the enzymatic machinery for sphingolipid production have been identified in T1DM individuals. Evidence gained from studies in rodent islets and beta-cells exposed to cytokines indicates dysregulation of the sphingolipid biosynthetic pathway and impaired function of several sphingolipids. Moreover, a number of glycosphingolipids have been suggested to act as beta-cell autoantigens. Studies in animal models of autoimmune diabetes, such as the Non Obese Diabetic (NOD) mouse and the LEW.1AR1-iddm (IDDM) rat, indicate a crucial role of sphingolipids in immune cell trafficking, islet infiltration and diabetes development. In this review, the up-to-date status on the findings about sphingolipids in T1DM will be provided, the under-investigated research areas will be identified and perspectives for future studies will be given.
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Korbecki J, Gutowska I, Kojder I, Jeżewski D, Goschorska M, Łukomska A, Lubkowska A, Chlubek D, Baranowska-Bosiacka I. New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection. Oncotarget 2018; 9:7219-7270. [PMID: 29467963 PMCID: PMC5805549 DOI: 10.18632/oncotarget.24102] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 01/02/2018] [Indexed: 11/25/2022] Open
Abstract
Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the 'hallmarks of cancer' in glioblastoma multiforme. Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (Treg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme.
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland.,Department of Biochemistry and Molecular Biology, Faculty of Health Sciences, University of Bielsko-Biała, 43-309 Bielsko-Biała, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland
| | - Ireneusz Kojder
- Department of Applied Neurocognitivistics, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland.,Department of Neurosurgery, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland
| | - Dariusz Jeżewski
- Department of Applied Neurocognitivistics, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland.,Department of Neurosurgery, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Agnieszka Łukomska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland
| | - Anna Lubkowska
- Department of Functional Diagnostics and Physical Medicine, Pomeranian Medical University in Szczecin, 71-210 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
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Frei AW, Li Y, Jiang K, Buchwald P, Stabler CL. Local delivery of fingolimod from three‐dimensional scaffolds impacts islet graft efficacy and microenvironment in a murine diabetic model. J Tissue Eng Regen Med 2017; 12:393-404. [DOI: 10.1002/term.2464] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 03/20/2017] [Accepted: 05/04/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Anthony W. Frei
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of Florida Gainesville FL USA
- Diabetes Research InstituteUniversity of Miami Miami FL USA
| | - Ying Li
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of Florida Gainesville FL USA
- Department of Pathology, Immunology, and Laboratory MedicineUniversity of Florida Gainesville FL USA
| | - Kaiyuan Jiang
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of Florida Gainesville FL USA
- Diabetes Research InstituteUniversity of Miami Miami FL USA
| | - Peter Buchwald
- Diabetes Research InstituteUniversity of Miami Miami FL USA
| | - Cherie L. Stabler
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of Florida Gainesville FL USA
- Diabetes Research InstituteUniversity of Miami Miami FL USA
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Chhabra P, Brayman KL. Overcoming barriers in clinical islet transplantation: current limitations and future prospects. Curr Probl Surg 2014; 51:49-86. [PMID: 24411187 DOI: 10.1067/j.cpsurg.2013.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Yin Z, Fan L, Wei L, Gao H, Zhang R, Tao L, Cao F, Wang H. FTY720 protects cardiac microvessels of diabetes: a critical role of S1P1/3 in diabetic heart disease. PLoS One 2012; 7:e42900. [PMID: 22916176 PMCID: PMC3419247 DOI: 10.1371/journal.pone.0042900] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 07/13/2012] [Indexed: 01/07/2023] Open
Abstract
Background: Diabetes is associated with an increased risk of cardiac microvascular disease. The mechanisms by which this damage occurs are unknown. However, research suggests that signaling through the sphingosine-1-phosphates receptor 1 and 3 (S1P1/3) by FTY720, a sphiongolipid drug that is structually similar to SIP, may play a role in the treatment on cardiac microvascular dysfunction in diabetes. We hypothesized that FTY720 might exert the cardioprotective effects of S1P1 and S1P3 viaprotein kinase C-beta (PKCβ II) signaling pathway. Methodology/Principal Findings: Transthoracic echocardiography was performed to detect the change of cardiac function. Scanning and transmission electron microscope with lanthanum tracer were used to determine microvascular ultrastructure and permeability in vivo. Apoptosis was detected by TUNEL and CD31 dual labeling in paraffin-embedded sections. Laser capture miscrodissection was used to assess cardiac micovascular endothelial cells (CMECs) in vivo. RT-PCR and Western blot analysis were used to determine the mRNA levels and protein expression of S1P1, S1P3, and PKCβ II. In the diabetic rats vs. controls, cardiac capillaries showed significantly higher density; CD31 positive endothelial cells were significantly reduced; the apoptosis index of cardiac endothlial cells was significantly higher. And FTY720 could increase the expressional level of S1P1 and boost S1P3 trasnslocation from membrane to nuclear, then ameliorate cardiac microvascular barrier impairment and pathologic angiogenesis induced by diabetes. In addition, overexpression of PKCβ II significantly decreased the protective effect of FTY720. Conclusions: Our study represents that the deregulation of S1P1 and S1P3 is an important signalresponsible for cardiac microvascular dysfunction in diabetes. FTY720 might be competent to serve as a potential therapeutic approach for diabetic heart disease through ameliorating cardiac microvascular barrier impairment and pathologic angiogenesis, which might be partly dependent on PKCβII-mediated signaling pathway.
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Affiliation(s)
- Zhiyong Yin
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Linni Fan
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Liping Wei
- Department of Cardiology, Tianjin Union Medicine Center, Tianjin, China
| | - Haokao Gao
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Rongqing Zhang
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Ling Tao
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Feng Cao
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
| | - Haichang Wang
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi’an City, Shaanxi Province, China
- * E-mail:
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10
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Abstract
Recent technical advances have re-invigorated the study of sphingolipid metabolism in general, and helped to highlight the varied and important roles that sphingolipids play in pancreatic β-cells. Sphingolipid metabolites such as ceramide, glycosphingolipids, sphingosine 1-phosphate and gangliosides modulate many β-cell signaling pathways and processes implicated in β-cell diabetic disease such as apoptosis, β-cell cytokine secretion, ER-to-golgi vesicular trafficking, islet autoimmunity and insulin gene expression. They are particularly relevant to lipotoxicity. Moreover, the de novo synthesis of sphingolipids occurs on many subcellular membranes, in parallel to secretory vesicle formation, traffic and granule maturation events. Indeed, the composition of the plasma membrane, determined by the activity of neutral sphingomyelinases, affects β-cell excitability and potentially insulin exocytosis while another glycosphingolipid, sulfatide, determines the stability of insulin crystals in granules. Most importantly, sphingolipid metabolism on internal membranes is also strongly implicated in regulating β-cell apoptosis.
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Affiliation(s)
- Ebru Boslem
- Diabetes and Obesity Program; Garvan Institute of Medical Research; Darlinghurst, NSW Australia
- St Vincent’s Clinical School; Faculty of Medicine; University of New South Wales; Sydney, NSW Australia
| | - Peter J. Meikle
- Baker IDI Heart and Diabetes Institute; Melbourne, VIC Australia
| | - Trevor J. Biden
- Diabetes and Obesity Program; Garvan Institute of Medical Research; Darlinghurst, NSW Australia
- St Vincent’s Clinical School; Faculty of Medicine; University of New South Wales; Sydney, NSW Australia
- Correspondence to: Trevor J. Biden,
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Keren Z, Averbuch D, Shahaf G, Zisman-Rozen S, Golan K, Itkin T, Lapidot T, Mehr R, Melamed D. Chronic B Cell Deficiency from Birth Prevents Age-Related Alterations in the B Lineage. THE JOURNAL OF IMMUNOLOGY 2011; 187:2140-7. [DOI: 10.4049/jimmunol.1100999] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Fox TE, Kester M. Therapeutic strategies for diabetes and complications: a role for sphingolipids? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:206-16. [PMID: 20919656 DOI: 10.1007/978-1-4419-6741-1_14] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diabetes is a debilitating chronic disease that has no cure and can only be managed by pharmaceutical or nutritional interventions. Worldwide, the incidence of diabetes and diabetic complications is dramatically increasing. This may reflect the incomplete knowledge base underlying the role of inflammatory or nutritional stresses to exacerbate diabetic complications. Despite the knowledge that hyperlipidemia is a cardinal feature of both Type 1 and 2 diabetes, the actual lipid species that contribute to complications such as diabetic nephropathy, retinopathy, neuropathy and cardiovascular disease have not been well defined, or have not elucidated new treatment strategies. Sphingolipids comprise only a fraction of total lipids but a body of evidence has now identified dysfunctional sphingolipid metabolism and/or generation of specific sphingolipid metabolites as contributors to diabetic complications. This review suggests that pharmacological therapies that target dysfunctional sphingolipid metabolism and/or signaling may prove beneficial in decreasing the chronic pathology of hyperglycemia and hyperlipidemia. Moreover, the review suggests that these treatment options may also prove beneficial to ameliorate or delay pancreatic beta cell failure.
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Affiliation(s)
- Todd E Fox
- Penn State College of Medicine, Department of Pharmacology, Hershey, Pennsylvania 17033, USA
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Mineo D, Sageshima J, Burke GW, Ricordi C. Minimization and withdrawal of steroids in pancreas and islet transplantation. Transpl Int 2008; 22:20-37. [PMID: 18855850 DOI: 10.1111/j.1432-2277.2008.00761.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
For reducing the corticosteroid (CS)-related side-effects, especially cardiovascular events, CS-sparing protocols have become increasingly common in pancreas transplantation (PT). Lympho-depleting induction antibodies, such as rabbit anti-thymocyte globulin (rATG) or alemtuzumab, have been widely used in successful trials. The results of various CS-sparing protocols combining calcineurin inhibitors (CNI) and mycophenolate or sirolimus, have been mixed for rejection and survival rates. Most of the studies were uncontrolled trials of low-risk patients, therefore the grade of evidence is limited. Large-scale prospective studies with long-term follow up are necessary to assess risks and benefits of CS-sparing regimens in PT before recommending such strategies as standard practice. Islet allo-transplantation for patients with brittle type 1 diabetes mellitus, less invasive and safer procedure than PT, has been attempted since late 1980s, but diabetogenic immunosuppressants at maintenance, mainly CS and high-dose CNI, prevented satisfactory results (10% insulin-independence at 1-year post-transplant). Since 2000, CS-free and CNI-reducing protocols, including more potent induction [daclizumab, OKT3gamma1(ala-ala) anti-CD3 antibody, rATG] and maintenance (sirolimus, mycophenolate) agents, have significantly improved short-term outcomes whereas long-term are still inadequate (from 80% to 20% insulin-independence from 1- to 5-year post-transplant). Main limitations are allo- and autoimmunity, immunosuppression-related islet and systemic toxicity and transplant site unsuitability, which tolerogenic protocols and biotechnological solutions may solve.
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Affiliation(s)
- Davide Mineo
- Diabetes Research Institute, University of Miami, FL 33136, USA
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Holland WL, Summers SA. Sphingolipids, insulin resistance, and metabolic disease: new insights from in vivo manipulation of sphingolipid metabolism. Endocr Rev 2008; 29:381-402. [PMID: 18451260 PMCID: PMC2528849 DOI: 10.1210/er.2007-0025] [Citation(s) in RCA: 428] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Obesity and dyslipidemia are risk factors for metabolic disorders including diabetes and cardiovascular disease. Sphingolipids such as ceramide and glucosylceramides, while being a relatively minor component of the lipid milieu in most tissues, may be among the most pathogenic lipids in the onset of the sequelae associated with excess adiposity. Circulating factors associated with obesity (e.g., saturated fatty acids, inflammatory cytokines) selectively induce enzymes that promote sphingolipid synthesis, and lipidomic profiling reveals relationships between tissue sphingolipid levels and certain metabolic diseases. Moreover, studies in cultured cells and isolated tissues implicate sphingolipids in certain cellular events associated with diabetes and cardiovascular disease, including insulin resistance, pancreatic beta-cell failure, cardiomyopathy, and vascular dysfunction. However, definitive evidence that sphingolipids contribute to insulin resistance, diabetes, and atherosclerosis has come only recently, as researchers have found that pharmacological inhibition or genetic ablation of enzymes controlling sphingolipid synthesis in rodents ameliorates each of these conditions. Herein we will review the role of ceramide and other sphingolipid metabolites in insulin resistance, beta-cell failure, cardiomyopathy, and vascular dysfunction, focusing on these in vivo studies that identify enzymes controlling sphingolipid metabolism as therapeutic targets for combating metabolic disease.
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Affiliation(s)
- William L Holland
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84132, USA
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