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Song SE, Shin SK, Ju HY, Im SS, Song DK. Role of cytosolic and endoplasmic reticulum Ca 2+ in pancreatic beta-cells: pros and cons. Pflugers Arch 2024; 476:151-161. [PMID: 37940681 DOI: 10.1007/s00424-023-02872-2] [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: 09/04/2023] [Revised: 10/18/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Pancreatic beta cells utilize Ca2+ to secrete insulin in response to glucose. The glucose-dependent increase in cytosolic Ca2+ concentration ([Ca2+]C) activates a series of insulin secretory machinery in pancreatic beta cells. Therefore, the amount of insulin secreted in response to glucose is determined in a [Ca2+]C-dependent manner, at least within a moderate range. However, the demand for insulin secretion may surpass the capability of beta cells. Abnormal elevation of [Ca2+]C levels beyond the beta-cell endurance capacity can damage them by inducing endoplasmic reticulum (ER) stress and cell death programs such as apoptosis. Therefore, while Ca2+ is essential for the insulin secretory functions of beta cells, it could affect their survival at pathologically higher levels. Because an increase in beta-cell [Ca2+]C is inevitable under certain hazardous conditions, understanding the regulatory mechanism for [Ca2+]C is important. Therefore, this review discusses beta-cell function, survival, ER stress, and apoptosis associated with intracellular and ER Ca2+ homeostasis.
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Affiliation(s)
- Seung-Eun Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Su-Kyung Shin
- Department of Food Science and Nutrition, Kyungpook National University, Daegu, South Korea
| | - Hyeon Yeong Ju
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Seung-Soon Im
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Dae-Kyu Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea.
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Chang G, Ying L, Zhang Q, Feng B, Yao R, Ding Y, Li J, Huang X, Shen Y, Yu T, Wang J, Wang X. Genetic variants of ABCC8 and clinical manifestations in eight Chinese children with hyperinsulinemic hypoglycemia. BMC Endocr Disord 2024; 24:8. [PMID: 38212772 PMCID: PMC10785495 DOI: 10.1186/s12902-023-01527-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 12/06/2023] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND ABCC8 variants can cause hyperinsulinemia by activating or deactivating gene expression. This study used targeted exon sequencing to investigate genetic variants of ABCC8 and the associated phenotypic features in Chinese patients with hyperinsulinemic hypoglycemia (HH). METHODS We enrolled eight Chinese children with HH and analyzed their clinical characteristics, laboratory results, and genetic variations. RESULTS The age at presentation among the patients ranged from neonates to 0.6 years old, and the age at diagnosis ranged from 1 month to 5 years, with an average of 1.3 ± 0.7 years. Among these patients, three presented with seizures, and five with hypoglycemia. One patient (Patient 7) also had microcephaly. All eight patients exhibited ABCC8 abnormalities, including six missense mutations (c. 2521 C > G, c. 3784G > A, c. 4478G > A, c. 4532T > C, c. 2669T > C, and c. 331G > A), two deletion-insertion mutations (c. 3126_3129delinsTC and c. 3124_3126delins13), and one splicing mutation (c. 1332 + 2T > C). Two of these mutations (c. 3126_3129delinsTC and c. 4532T > C) are novel. Six variations were paternal, two were maternal, and one was de novo. Three patients responded to diazoxide and one patient responded to octreotide treatment. All there patients had diazoxide withdrawal with age. Two patients (patients 3 and 7) were unresponsive to both diazoxide and octreotide and had mental retardation. CONCLUSIONS Gene analysis can aid in the classification, treatment, and prognosis of children with HH. In this study, the identification of seven known and two novel variants in the ABCC8 gene further enriched the variation spectrum of the gene.
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Affiliation(s)
- Guoying Chang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Lingwen Ying
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Qianwen Zhang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Biyun Feng
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Ruen Yao
- Department of Medical Genetics and Molecular Diagnostics laboratory, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
| | - Yu Ding
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Juan Li
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Xiaodong Huang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Yongnian Shen
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China
| | - Tingting Yu
- Department of Medical Genetics and Molecular Diagnostics laboratory, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
| | - Jian Wang
- International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, 200030, Shanghai, China.
| | - Xiumin Wang
- Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, 1678 Dongfang Road, 200127, Shanghai, China.
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3
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Wu W, Zheng J, Wang R, Wang Y. Ion channels regulate energy homeostasis and the progression of metabolic disorders: Novel mechanisms and pharmacology of their modulators. Biochem Pharmacol 2023; 218:115863. [PMID: 37863328 DOI: 10.1016/j.bcp.2023.115863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/13/2023] [Accepted: 10/16/2023] [Indexed: 10/22/2023]
Abstract
The progression of metabolic diseases, featured by dysregulated metabolic signaling pathways, is orchestrated by numerous signaling networks. Among the regulators, ion channels transport ions across the membranes and trigger downstream signaling transduction. They critically regulate energy homeostasis and pathogenesis of metabolic diseases and are potential therapeutic targets for treating metabolic disorders. Ion channel blockers have been used to treat diabetes for decades by stimulating insulin secretion, yet with hypoglycemia and other adverse effects. It calls for deeper understanding of the largely elusive regulatory mechanisms, which facilitates the identification of new therapeutic targets and safe drugs against ion channels. In the article, we critically assess the two principal regulatory mechanisms, protein-channel interaction and post-translational modification on the activities of ion channels to modulate energy homeostasis and metabolic disorders through multiple novel mechanisms. Moreover, we discuss the multidisciplinary methods that provide the tools for elucidation of the regulatory mechanisms mediating metabolic disorders by ion channels. In terms of translational perspective, the mechanistic analysis of recently validated ion channels that regulate insulin resistance, body weight control, and adverse effects of current ion channel antagonists are discussed in details. Their small molecule modulators serve as promising new drug candidates to combat metabolic disorders.
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Affiliation(s)
- Wenyi Wu
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Jianan Zheng
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Ru Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; Shanghai Frontiers Science Research Base of Exercise and Metabolic Health, China
| | - Yibing Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; Shanghai Frontiers Science Research Base of Exercise and Metabolic Health, China.
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ATP-Sensitive Potassium Channels in Migraine: Translational Findings and Therapeutic Potential. Cells 2022; 11:cells11152406. [PMID: 35954249 PMCID: PMC9367966 DOI: 10.3390/cells11152406] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/29/2022] [Accepted: 07/30/2022] [Indexed: 12/10/2022] Open
Abstract
Globally, migraine is a leading cause of disability with a huge impact on both the work and private life of affected persons. To overcome the societal migraine burden, better treatment options are needed. Increasing evidence suggests that ATP-sensitive potassium (KATP) channels are involved in migraine pathophysiology. These channels are essential both in blood glucose regulation and cardiovascular homeostasis. Experimental infusion of the KATP channel opener levcromakalim to healthy volunteers and migraine patients induced headache and migraine attacks in 82-100% of participants. Thus, this is the most potent trigger of headache and migraine identified to date. Levcromakalim likely induces migraine via dilation of cranial arteries. However, other neuronal mechanisms are also proposed. Here, basic KATP channel distribution, physiology, and pharmacology are reviewed followed by thorough review of clinical and preclinical research on KATP channel involvement in migraine. KATP channel opening and blocking have been studied in a range of preclinical migraine models and, within recent years, strong evidence on the importance of their opening in migraine has been provided from human studies. Despite major advances, translational difficulties exist regarding the possible anti-migraine efficacy of KATP channel blockage. These are due to significant species differences in the potency and specificity of pharmacological tools targeting the various KATP channel subtypes.
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Mori Y, Miyake M, Hosoda Y, Miki A, Takahashi A, Muraoka Y, Miyata M, Sato T, Tamura H, Ooto S, Yamada R, Yamashiro K, Nakamura M, Tajima A, Nagasaki M, Honda S, Tsujikawa A. Genome-wide Survival Analysis for Macular Neovascularization Development in Central Serous Chorioretinopathy Revealed Shared Genetic Susceptibility with Polypoidal Choroidal Vasculopathy. Ophthalmology 2022; 129:1034-1042. [PMID: 35490733 DOI: 10.1016/j.ophtha.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/04/2022] [Accepted: 04/22/2022] [Indexed: 10/18/2022] Open
Abstract
PURPOSE To identify susceptibility genes for macular neovascularization (MNV) development in central serous chorioretinopathy (CSC). DESIGN Genome-wide survival analysis using a longitudinal cohort study. PARTICIPANTS We included 402 and 137 patients with CSC but without MNV at their first visit from the Kyoto CSC Cohort and Kobe CSC dataset, respectively. All patients underwent detailed ophthalmologic examinations, including multimodal imaging, such as fundus autofluorescence, spectral-domain optical coherence tomography, and fluorescein angiography/indocyanine green angiography and/or optimal coherence tomography angiography. METHODS We conducted a genome-wide survival analysis using the Kyoto CSC Cohort. We applied the Cox proportional hazard model to adjust for age, sex, and the first principal component. Single nucleotide polymorphisms (SNPs) with P-values <1.0×10-5 were carried forward to the replication in the Kobe CSC dataset. Moreover, we evaluated the contribution of previously-reported age-related macular degeneration (AMD) susceptibility loci. We used FUMA and ToppFun for the functional enrichment analysis. MAIN OUTCOME MEASURES The association between SNPs and MNV development in patients with CSC. RESULTS Rs370974631 near ARMS2 displayed a genome-wide significant association in the meta-analysis of discovery and replication result (hazard ratio [HR]meta = 3.63; Pmeta = 5.76×10-9). Among previously-reported AMD susceptibility loci, we additionally identified CFH rs800292 (HR = 0.39, P = 2.55×10-4), COL4A3 rs4276018 (HR = 0.26, P = 1.56×10-3), and B3GALTL rs9564692 (HR = 0.56, P = 8.30×10-3) as susceptibility loci for MNV development in CSC. The functional enrichment analysis revealed significant enrichment of eight pathways (GO:0051561, GO:0036444, GO:0008282, GO:1990246, GO:0015272, GO:0030955, GO:0031420, and GO:0005242) related to ion transport. CONCLUSIONS ARMS2, CFH, COL4A3, and B3GALTL were identified as susceptibility genes for MNV development in CSC. The aforementioned four genes are known as susceptibility genes for AMD, whereas COL4A3 and B3GALTL were previously reported to be polypoidal choroidal vasculopathy (PCV)-specific susceptibility genes. Our findings revealed the shared genetic susceptibility between PCV and MNV secondary to CSC.
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Affiliation(s)
- Yuki Mori
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan; Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masahiro Miyake
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan; Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | | | - Akiko Miki
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ayako Takahashi
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuki Muraoka
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Manabu Miyata
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takehiro Sato
- Department of Bioinformatics and Genomics, Graduate School of Advanced Preventive Medical Sciences, Kanazawa University, Kanazawa, Ishikawa Japan
| | - Hiroshi Tamura
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Sotaro Ooto
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryo Yamada
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kenji Yamashiro
- Department of Ophthalmology and Visual Science, Kochi Medical School, Kochi University, Nankoku City, Kochi, Japan
| | - Makoto Nakamura
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Atsushi Tajima
- Department of Bioinformatics and Genomics, Graduate School of Advanced Preventive Medical Sciences, Kanazawa University, Kanazawa, Ishikawa Japan
| | - Masao Nagasaki
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shigeru Honda
- Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Akitaka Tsujikawa
- Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Wen Z, Wang J, Liang Q, Chang X, Zhang W, Niu H, He Q. Laparoscopic Surgery for Focal-Form Congenital Hyperinsulinism Located in Pancreatic Head. Front Pediatr 2022; 10:919238. [PMID: 35928676 PMCID: PMC9343681 DOI: 10.3389/fped.2022.919238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/20/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND AIMS Congenital hyperinsulinism of infancy (CHI) is a rare condition that may cause irreversible severe neurological damage in infants. For children in whom medical management fails, partial or near-total pancreatectomy is then required according to the type of lesion. Currently, open surgery of near-total pancreatic head resection is a mature technique for the treatment of focal-form CHI located in the head of the pancreas, but a minimally invasive laparoscopic procedure has not been reported yet. The aim of this study was to verify the feasibility, safety, and efficacy of laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy for focal-form CHI. METHODS Two infants with persistent hypoglycemia and increased insulin levels were diagnosed with CHI and underwent laparoscopic near-total pancreatic head resection due to a suboptimal response to medical therapy and the likelihood of focal disease amenable to surgery. Clinical records, operative findings, and postoperative follow-up were collected and analyzed. RESULTS The operative duration was 300-330 min, and the intraoperative blood loss was minimal. The duration of postoperative abdominal drainage was 4-5 days. Neither intra- nor postoperative abdominal complications occurred. Oral feeding was resumed 3-4 days after the operation, and the blood glucose level was gradually stabilized to within the normal range. Normal blood glucose was observed in both patients over a follow-up period of 3-6 months. CONCLUSIONS Laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy can be considered a safe and effective procedure with minimal morbidity and excellent outcomes for the treatment of focal CHI in the head of the pancreas.
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Affiliation(s)
- Zhe Wen
- Department of Pediatric Surgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Jieqin Wang
- Department of Pediatric Surgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Qifeng Liang
- Department of Pediatric Surgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xiaopan Chang
- Department of Pediatric Surgery, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Wen Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Huilin Niu
- Department of Pathology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Qiao He
- Department of Nuclear Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Worth C, Harper S, Salomon-Estebanez M, O'Shea E, Nutter PW, Dunne MJ, Banerjee I. Clustering of Hypoglycemia Events in Patients With Hyperinsulinism: Extension of the Digital Phenotype Through Retrospective Data Analysis. J Med Internet Res 2021; 23:e26957. [PMID: 34435596 PMCID: PMC8590184 DOI: 10.2196/26957] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 06/30/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023] Open
Abstract
Background Hyperinsulinism (HI) due to excess and dysregulated insulin secretion is the most common cause of severe and recurrent hypoglycemia in childhood. High cerebral glucose use in the early hours results in a high risk of hypoglycemia in people with diabetes and carries a significant risk of brain injury. Prevention of hypoglycemia is the cornerstone of the management of HI, but the risk of hypoglycemia at night or the timing of hypoglycemia in children with HI has not been studied; thus, the digital phenotype remains incomplete and management suboptimal. Objective This study aims to quantify the timing of hypoglycemia in patients with HI to describe glycemic variability and to extend the digital phenotype. This will facilitate future work using computational modeling to enable behavior change and reduce exposure of patients with HI to injurious hypoglycemic events. Methods Patients underwent continuous glucose monitoring (CGM) with a Dexcom G4 or G6 CGM device as part of their clinical assessment for either HI (N=23) or idiopathic ketotic hypoglycemia (IKH; N=24). The CGM data were analyzed for temporal trends. Hypoglycemia was defined as glucose levels <3.5 mmol/L. Results A total of 449 hypoglycemic events totaling 15,610 minutes were captured over 237 days from 47 patients (29 males; mean age 70 months, SD 53). The mean length of hypoglycemic events was 35 minutes. There was a clear tendency for hypoglycemia in the early hours (3-7 AM), particularly for patients with HI older than 10 months who experienced hypoglycemia 7.6% (1480/19,370 minutes) of time in this period compared with 2.6% (2405/92,840 minutes) of time outside this period (P<.001). This tendency was less pronounced in patients with HI who were younger than 10 months, patients with a negative genetic test result, and patients with IKH. Despite real-time CGM, there were 42 hypoglycemic events from 13 separate patients with HI lasting >30 minutes. Conclusions This is the first study to have taken the first step in extending the digital phenotype of HI by describing the glycemic trends and identifying the timing of hypoglycemia measured by CGM. We have identified the early hours as a time of high hypoglycemia risk for patients with HI and demonstrated that simple provision of CGM data to patients is not sufficient to eliminate hypoglycemia. Future work in HI should concentrate on the early hours as a period of high risk for hypoglycemia and must target personalized hypoglycemia predictions. Focus must move to the human-computer interaction as an aspect of the digital phenotype that is susceptible to change rather than simple mathematical modeling to produce small improvements in hypoglycemia prediction accuracy.
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Affiliation(s)
- Chris Worth
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Department of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Simon Harper
- Department of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Maria Salomon-Estebanez
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom
| | - Elaine O'Shea
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom
| | - Paul W Nutter
- Department of Computer Science, University of Manchester, Manchester, United Kingdom
| | - Mark J Dunne
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Indraneel Banerjee
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
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Tang LH. Pancreatic Neuroendocrine Neoplasms: Landscape and Horizon. Arch Pathol Lab Med 2021; 144:816-828. [PMID: 32298138 DOI: 10.5858/arpa.2019-0654-ra] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2020] [Indexed: 11/06/2022]
Abstract
CONTEXT.— Since the initial description of pancreatic endocrine physiology and the recognition of islet cell tumors in the 1800s, there have been noteworthy advances in the pathobiology of pancreatic neuroendocrine neoplasms (PanNENs), and definition of the important distinction between well-differentiated neuroendocrine tumor (PanNET) and poorly differentiated neuroendocrine carcinoma (PanNEC). The evolving knowledge has resulted in a continuous update in terminology, classification, and grading system for this group of neoplasms. Pancreatic neuroendocrine tumors associated with hereditary conditions have been linked to unique molecular and genetic events, and sporadic PanNETs have specific gene signatures. Based on accumulative experience and knowledge, therapeutic strategies have been defined for this group of neoplasms. OBJECTIVE.— To review the evolution and description of the pathologic-genomic evolution of PanNENs, and to facilitate accurate pathologic interpretation for the corresponding clinical management. DATA SOURCES.— Literature review of published studies and author's own work. CONCLUSIONS.— Evolving experience and knowledge have established subtypes of pancreatic neuroendocrine neoplasms, based on their genotype and phenotype. Accurate pathologic interpretation of the specific neoplasm has significant implications for therapy and prognosis.
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Affiliation(s)
- Laura H Tang
- From the Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York
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9
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Haris B, Saraswathi S, Hussain K. Somatostatin analogues for the treatment of hyperinsulinaemic hypoglycaemia. Ther Adv Endocrinol Metab 2020; 11:2042018820965068. [PMID: 33329885 PMCID: PMC7720331 DOI: 10.1177/2042018820965068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/11/2020] [Indexed: 01/10/2023] Open
Abstract
Hyperinsulinaemic hypoglycaemia (HH) is a biochemical finding of low blood glucose levels due to the dysregulation of insulin secretion from pancreatic β-cells. Under normal physiological conditions, glucose metabolism is coupled to β-cell insulin secretion so that blood glucose levels are maintained within the physiological range of 3.5-5.5 mmol/L. However, in HH this coupling of glucose metabolism to insulin secretion is perturbed so that insulin secretion becomes unregulated. HH typically occurs in the neonatal, infancy and childhood periods and can be due to many different causes. Adults can also present with HH but the causes in adults tend to be different. Somatostatin (SST) is a peptide hormone that is released by the delta cells (δ-cells) in the pancreas. It binds to G protein-coupled SST receptors to regulate a variety of location-specific and selective functions such as hormone inhibition, neurotransmission and cell proliferation. SST plays a potent role in the regulation of both insulin and glucagon secretion in response to changes in glucose levels by negative feedback mechanism. The half-life of SST is only 1-3 min due to quick degradation by peptidases in plasma and tissues. Thus, a direct continuous intravenous or subcutaneous infusion is required to achieve the therapeutic effect. These limitations prompted the discovery of SST analogues such as octreotide and lanreotide, which have longer half-lives and therefore can be administered as injections. SST analogues are used to treat different forms of HH in children and adults and therapeutic effect is achieved by suppressing insulin secretion from pancreatic β-cells by complex mechanisms. These treatments are associated with several side effects, especially in the newborn period, with necrotizing enterocolitis being the most serious side effect and hence SS analogues should be used with extreme caution in this age group.
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Affiliation(s)
- Basma Haris
- Department of Paediatric Medicine, Division of Endocrinology, Sidra Medicine, Doha, Qatar
| | - Saras Saraswathi
- Department of Paediatric Medicine, Division of Endocrinology, Sidra Medicine, Doha, Qatar
| | - Khalid Hussain
- Professor of Paediatrics, Weill Cornell Medicine-Qatar, Division Chief – Endocrinology, Department of Paediatric Medicine, Division of Endocrinology, Sidra Medicine, OPC, C6-340 |PO Box 26999, Al Luqta Street, Education City North Campus, Doha, Qatar
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10
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Abstract
A multidisciplinary approach to patients with congenital hyperinsulinism (HI) can distinguish focal from diffuse HI, localize focal lesions, and permit partial pancreatectomy with cure in almost all focal patients. Surgery does not cure diffuse disease but can help prevent severe hypoglycemia and brain damage. Surgery can be curative for insulinoma and for some cases of atypical HI.
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Affiliation(s)
- N Scott Adzick
- Department of Surgery and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia, and the Perelman School of Medicine at the University of Pennsylvania, 3401 Civic Center Boulevard, Philadelphia, PA 19104, United States.
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11
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Law NC, Marinelli I, Bertram R, Corbin KL, Schildmeyer C, Nunemaker CS. Chronic stimulation induces adaptive potassium channel activity that restores calcium oscillations in pancreatic islets in vitro. Am J Physiol Endocrinol Metab 2020; 318:E554-E563. [PMID: 32069073 PMCID: PMC7191410 DOI: 10.1152/ajpendo.00482.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin pulsatility is important to hepatic response in regulating blood glucose. Growing evidence suggests that insulin-secreting pancreatic β-cells can adapt to chronic disruptions of pulsatility to rescue this physiologically important behavior. We determined the time scale for adaptation and examined potential ion channels underlying it. We induced the adaptation both by chronic application of the ATP-sensitive K+ [K(ATP)] channel blocker tolbutamide and by application of the depolarizing agent potassium chloride (KCl). Acute application of tolbutamide without pretreatment results in elevated Ca2+ as measured by fura-2AM and the loss of endogenous pulsatility. We show that after chronic exposure to tolbutamide (12-24 h), Ca2+ oscillations occur with subsequent acute tolbutamide application. The same experiment was conducted with potassium chloride (KCl) to directly depolarize the β-cells. Once again, following chronic exposure to the cell stimulator, the islets produced Ca2+ oscillations when subsequently exposed to tolbutamide. These experiments suggest that it is the chronic stimulation, and not tolbutamide desensitization, that is responsible for the adaptation that rescues oscillatory β-cell activity. This compensatory response also causes islet glucose sensitivity to shift rightward following chronic tolbutamide treatment. Mathematical modeling shows that a small increase in the number of K(ATP) channels in the membrane is one adaptation mechanism that is compatible with the data. To examine other compensatory mechanisms, pharmacological studies provide support that Kir2.1 and TEA-sensitive channels play some role. Overall, this investigation demonstrates β-cell adaptability to overstimulation, which is likely an important mechanism for maintaining glucose homeostasis in the face of chronic stimulation.
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Affiliation(s)
- Nathan C Law
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | | | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida
| | - Kathryn L Corbin
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Cara Schildmeyer
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Craig S Nunemaker
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
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Kostopoulou E, Shah P. Hyperinsulinaemic hypoglycaemia-an overview of a complex clinical condition. Eur J Pediatr 2019; 178:1151-1160. [PMID: 31243576 DOI: 10.1007/s00431-019-03414-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/18/2022]
Abstract
Hyperinsulinaemic hypoglycaemia (HH) is a major cause of hypoglycaemia in the neonatal period, infancy and childhood. It is caused by unsuppressed insulin secretion in the setting of hypoglycaemia and carries a high risk of significant neurological sequelae, such as cognitive impairment. Genetic mutations have been implicated in the pathogenesis of the condition. Other causes include intra-uterine growth retardation, perinatal asphyxia, maternal diabetes mellitus and syndromes, such as Beckwith-Wiedemann. Based on the aetiology, the clinical presentation can range from absence of symptoms to the typical adrenergic symptoms and coma and even death. The diagnosis is based on biochemical findings and the gold-standard imaging technique is 18F-DOPA PET/CT scanning. Treatment options involve medications, such as diazoxide, nifedipine, glucagon and octreotide, as well as surgery. Novel treatment, such as long-acting octreotide, lanreotide and sirolimus, may be used as an alternative to pancreatectomy. Potential future medical treatments include exendin, a GLP-1 receptor antagonist, and glucagon infusion via a pump.Conclusion: Advances in the fields of genetic testing, imaging techniques and medical treatment are beginning to provide novel insights into earlier detection, less invasive treatment approaches and fewer complications associated with the complex entity of hyperinsulinaemic hypoglycaemia. What is Known: • HH is caused by dysregulated insulin release from the β cell due to genetic mutations and carries a risk for complications, such as neurocognitive impairment. 18F-DOPA PET/CT scanning is presented as the gold-standard imaging technique currently in children with hyperinsulinaemic hypoglycaemia. • Clinical presentation is heterogeneous and treatment options include medical therapy and pancreatectomy. What is New: • 18F-DOPA PET/CT is indicated in suspected focal CHI due to paternal transmitted mutations in ABCC8 or KCNJ11. • Novel treatment options have been introduced, such as long-acting octreotide, lanreotide, sirolimus and selective nonpeptide somatostatin receptor subtype 5 (SSTR5) agonists. Future medical treatments include exendin, a GLP-1 antagonist, and glucagon infusion via a pump. However, all these options are off-label at present.
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Affiliation(s)
- Eirini Kostopoulou
- Research Laboratory of the Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics, School of Medicine, University of Patras, 26500, Patras, Greece.
| | - Pratik Shah
- Endocrinology Department, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
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13
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Al-Badi MK, Al-Azkawi HS, Al-Yahyaei MS, Mula-Abed WA, Al-Senani AM. Clinical characteristics and phenotype-genotype review of 25 Omani children with congenital hyperinsulinism in infancy. A one-decade single-center experience. Saudi Med J 2019; 40:669-674. [PMID: 31287126 PMCID: PMC6757195 DOI: 10.15537/smj.2019.7.24291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Objectives: To report the genotype-phenotype characteristics, demographic features and clinical outcome of Omani patients with congenital hyperinsulinism (CHI). Methods: We retrospectively analyzed the clinical, biochemical, genotypical, phenotypical characteristics and outcomes of children with CHI who were presented to the pediatric endocrine team in the Royal Hospital, Muscat, Oman between January 2007 and December 2016. Results: Analysis of 25 patients with CHI genetically revealed homozygous mutation in ABCC8 in 23 (92%) patients and 2 patients (8%) with compound heterozygous mutation in ABCC8. Fifteen (60%) patients underwent subtotal pancreatectomy as medical therapy failed and 2 (8%) patients showed response to medical therapy. Three patients expired during the neonatal period, 2 had cardiomyopathy and sepsis, and one had sepsis and severe metabolic acidosis. Out of the 15 patients who underwent pancreatectomy, 6 developed diabetes mellitus, 6 continued to have hypoglycemia and required medical therapy and one had pancreatic exocrine dysfunction post-pancreatectomy, following up with gastroenterology clinic and was placed on pancreatic enzyme supplements, while 2 patients continued to have hypoglycemia and both had abdominal MRI and 18-F-fluoro-L-DOPA positron emission tomography scan (PET-scan), that showed persistent of the disease and started on medical therapy. Conclusion: Mutation in ABCC8 is the most common cause of CHI and reflects the early age of presentation. There is a need for early diagnosis and appropriate therapeutic strategy.
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Affiliation(s)
- Maryam K Al-Badi
- Department of Pediatric Endocrinology, National Diabetes and Endocrine Centre, Muscat, Sultanate of Oman. E-mail.
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14
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Galcheva S, Demirbilek H, Al-Khawaga S, Hussain K. The Genetic and Molecular Mechanisms of Congenital Hyperinsulinism. Front Endocrinol (Lausanne) 2019; 10:111. [PMID: 30873120 PMCID: PMC6401612 DOI: 10.3389/fendo.2019.00111] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 12/13/2022] Open
Abstract
Congenital hyperinsulinism (CHI) is a heterogenous and complex disorder in which the unregulated insulin secretion from pancreatic beta-cells leads to hyperinsulinaemic hypoglycaemia. The severity of hypoglycaemia varies depending on the underlying molecular mechanism and genetic defects. The genetic and molecular causes of CHI include defects in pivotal pathways regulating the secretion of insulin from the beta-cell. Broadly these genetic defects leading to unregulated insulin secretion can be grouped into four main categories. The first group consists of defects in the pancreatic KATP channel genes (ABCC8 and KCNJ11). The second and third categories of conditions are enzymatic defects (such as GDH, GCK, HADH) and defects in transcription factors (for example HNF1α, HNF4α) leading to changes in nutrient flux into metabolic pathways which converge on insulin secretion. Lastly, a large number of genetic syndromes are now linked to hyperinsulinaemic hypoglycaemia. As the molecular and genetic basis of CHI has expanded over the last few years, this review aims to provide an up-to-date knowledge on the genetic causes of CHI.
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Affiliation(s)
- Sonya Galcheva
- Department of Paediatrics, University Hospital St. Marina, Varna Medical University, Varna, Bulgaria
| | - Hüseyin Demirbilek
- Department of Paediatric Endocrinology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sara Al-Khawaga
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
- *Correspondence: Khalid Hussain
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15
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Adzick NS, De Leon DD, States LJ, Lord K, Bhatti TR, Becker SA, Stanley CA. Surgical treatment of congenital hyperinsulinism: Results from 500 pancreatectomies in neonates and children. J Pediatr Surg 2019; 54:27-32. [PMID: 30343978 PMCID: PMC6339589 DOI: 10.1016/j.jpedsurg.2018.10.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 10/01/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Congenital Hyperinsulinism (HI) causes severe hypoglycemia in neonates and children. We reviewed our experience with pancreatectomy for the various types of HI. METHODS From 1998 to 2018, 500 patients with HI underwent pancreatectomy: 246 for focal HI, 202 for diffuse HI, 37 for atypical HI (16 for Localized Islet Nuclear Enlargement [LINE], 21 for Beckwith-Wiedemann Syndrome), and 15 for insulinoma. Focal HI neonates were treated with partial pancreatectomy. Patients with diffuse HI who failed medical management underwent near-total (98%) pancreatectomy. Atypical HI patients had pancreatectomies tailored to the PET scan and biopsy findings. RESULTS The vast majority of pancreatectomies for focal HI were < 50%, and many were 2%-10%. 97% of focal HI patients are cured. For diffuse disease patients, 31% were euglycemic, 20% were hyperglycemic, and 49% required treatment for hypoglycemia; the incidence of diabetes increased with long-term follow-up. All 15 insulinoma patients were cured. CONCLUSIONS Our approach to patients with focal HI can distinguish focal from diffuse HI, localize focal lesions, and permit partial pancreatectomy with cure in almost all focal patients. Surgery does not cure diffuse disease but can help prevent severe hypoglycemia and brain damage. Surgery can be curative for insulinoma and for some cases of atypical HI. LEVEL OF EVIDENCE Level IV.
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Affiliation(s)
- N Scott Adzick
- Department of Surgery and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA.
| | - Diva D De Leon
- Department of Pediatrics and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Lisa J States
- Department of Radiology and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Katherine Lord
- Department of Pediatrics and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Tricia R Bhatti
- Department of Pathology and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Susan A Becker
- Department of Pediatrics and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Charles A Stanley
- Department of Pediatrics and the Congenital Hyperinsulinism Center, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
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16
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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17
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Abstract
Hyperinsulinaemic hypoglycaemia (HH) is a heterogeneous condition with dysregulated insulin secretion which persists in the presence of low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. Recent advances in genetics have linked congenital HH to mutations in 14 different genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1, PPM2, CACNA1D, FOXA2). Histologically, congenital HH can be divided into 3 types: diffuse, focal and atypical. Due to the biochemical basis of this condition, it is essential to diagnose and treat HH promptly in order to avoid the irreversible hypoglycaemic brain damage. Recent advances in the field of HH include new rapid molecular genetic testing, novel imaging methods (18F-DOPA PET/CT), novel medical therapy (long-acting octreotide formulations, mTOR inhibitors, GLP-1 receptor antagonists) and surgical approach (laparoscopic surgery). The review article summarizes the current diagnostic methods and management strategies for HH in children.
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Affiliation(s)
- Sonya Galcheva
- Dept. of Paediatrics, Varna Medical University/University Hospital "St. Marina", Varna, Bulgaria
| | - Sara Al-Khawaga
- Dept. of Paediatric Medicine, Division of Endocrinology, Sidra Medical & Research Center, Doha, Qatar
| | - Khalid Hussain
- Dept. of Paediatric Medicine, Division of Endocrinology, Sidra Medical & Research Center, Doha, Qatar.
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18
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Yildirim V, Vadrevu S, Thompson B, Satin LS, Bertram R. Upregulation of an inward rectifying K+ channel can rescue slow Ca2+ oscillations in K(ATP) channel deficient pancreatic islets. PLoS Comput Biol 2017; 13:e1005686. [PMID: 28749940 PMCID: PMC5549769 DOI: 10.1371/journal.pcbi.1005686] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 08/08/2017] [Accepted: 07/16/2017] [Indexed: 12/02/2022] Open
Abstract
Plasma insulin oscillations are known to have physiological importance in the regulation of blood glucose. In insulin-secreting β-cells of pancreatic islets, K(ATP) channels play a key role in regulating glucose-dependent insulin secretion. In addition, they convey oscillations in cellular metabolism to the membrane by sensing adenine nucleotides, and are thus instrumental in mediating pulsatile insulin secretion. Blocking K(ATP) channels pharmacologically depolarizes the β-cell plasma membrane and terminates islet oscillations. Surprisingly, when K(ATP) channels are genetically knocked out, oscillations in islet activity persist, and relatively normal blood glucose levels are maintained. Compensation must therefore occur to overcome the loss of K(ATP) channels in K(ATP) knockout mice. In a companion study, we demonstrated a substantial increase in Kir2.1 protein occurs in β-cells lacking K(ATP) because of SUR1 deletion. In this report, we demonstrate that β-cells of SUR1 null islets have an upregulated inward rectifying K+ current that helps to compensate for the loss of K(ATP) channels. This current is likely due to the increased expression of Kir2.1 channels. We used mathematical modeling to determine whether an ionic current having the biophysical characteristics of Kir2.1 is capable of rescuing oscillations that are similar in period to those of wild-type islets. By experimentally testing a key model prediction we suggest that Kir2.1 current upregulation is a likely mechanism for rescuing the oscillations seen in islets from mice deficient in K(ATP) channels. Pulsatile insulin secretion is important for the proper regulation of blood glucose, and disruption of this pulsatility is a hallmark of type II diabetes. An ion channel was discovered more than three decades ago that conveys the metabolic state of insulin-secreting β-cells to the plasma membrane because it is blocked by ATP and opened by ADP, and thereby controls the activity of these electrically-excitable cells on a rapid time scale according to the prevailing blood glucose level. In addition to setting the appropriate level of insulin secretion, K(ATP) channels play a key role in generating the oscillations in cellular activity that underlie insulin pulsatility. It is therefore surprising that oscillations in activity persist in islets in which the K(ATP) channels are genetically knocked out. In this combined modeling and experimental study, we demonstrate that the role played by K(ATP) current in wild-type β-cells can be taken over by an inward-rectifying K+ current which, we show here, is upregulated in β-cells from SUR1 knockout mice. This result helps to resolve a mystery in the field that has remained elusive for more than a decade, since the first studies showing oscillations in SUR1-/- islets.
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Affiliation(s)
- Vehpi Yildirim
- Department of Mathematics, Florida State University, Tallahassee, FL, United States of America
| | - Suryakiran Vadrevu
- Brehm Diabetes Center, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Benjamin Thompson
- Brehm Diabetes Center, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Leslie S. Satin
- Brehm Diabetes Center, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Richard Bertram
- Department of Mathematics and Programs in Molecular Biophysics and Neuroscience, Florida State University, Tallahassee, FL, United States of America
- * E-mail:
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19
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Li C, Ackermann AM, Boodhansingh KE, Bhatti TR, Liu C, Schug J, Doliba N, Han B, Cosgrove KE, Banerjee I, Matschinsky FM, Nissim I, Kaestner KH, Naji A, Adzick NS, Dunne MJ, Stanley CA, De León DD. Functional and Metabolomic Consequences of K ATP Channel Inactivation in Human Islets. Diabetes 2017; 66:1901-1913. [PMID: 28442472 PMCID: PMC5482088 DOI: 10.2337/db17-0029] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/15/2017] [Indexed: 12/17/2022]
Abstract
Loss-of-function mutations of β-cell KATP channels cause the most severe form of congenital hyperinsulinism (KATPHI). KATPHI is characterized by fasting and protein-induced hypoglycemia that is unresponsive to medical therapy. For a better understanding of the pathophysiology of KATPHI, we examined cytosolic calcium ([Ca2+] i ), insulin secretion, oxygen consumption, and [U-13C]glucose metabolism in islets isolated from the pancreases of children with KATPHI who required pancreatectomy. Basal [Ca2+] i and insulin secretion were higher in KATPHI islets compared with controls. Unlike controls, insulin secretion in KATPHI islets increased in response to amino acids but not to glucose. KATPHI islets have an increased basal rate of oxygen consumption and mitochondrial mass. [U-13C]glucose metabolism showed a twofold increase in alanine levels and sixfold increase in 13C enrichment of alanine in KATPHI islets, suggesting increased rates of glycolysis. KATPHI islets also exhibited increased serine/glycine and glutamine biosynthesis. In contrast, KATPHI islets had low γ-aminobutyric acid (GABA) levels and lacked 13C incorporation into GABA in response to glucose stimulation. The expression of key genes involved in these metabolic pathways was significantly different in KATPHI β-cells compared with control, providing a mechanism for the observed changes. These findings demonstrate that the pathophysiology of KATPHI is complex, and they provide a framework for the identification of new potential therapeutic targets for this devastating condition.
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Affiliation(s)
- Changhong Li
- Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Amanda M Ackermann
- Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Kara E Boodhansingh
- Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Tricia R Bhatti
- Department of Pathology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Chengyang Liu
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jonathan Schug
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Nicolai Doliba
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Bing Han
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, U.K
| | - Karen E Cosgrove
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, U.K
| | - Indraneel Banerjee
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, U.K
| | - Franz M Matschinsky
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Itzhak Nissim
- Division of Metabolism, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Klaus H Kaestner
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ali Naji
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - N Scott Adzick
- Department of Surgery, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Mark J Dunne
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, U.K
| | - Charles A Stanley
- Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Diva D De León
- Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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20
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Yildirim V, Bertram R. Calcium Oscillation Frequency-Sensitive Gene Regulation and Homeostatic Compensation in Pancreatic β-Cells. Bull Math Biol 2017; 79:1295-1324. [PMID: 28497293 DOI: 10.1007/s11538-017-0286-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/27/2017] [Indexed: 02/03/2023]
Abstract
Pancreatic islet [Formula: see text]-cells are electrically excitable cells that secrete insulin in an oscillatory fashion when the blood glucose concentration is at a stimulatory level. Insulin oscillations are the result of cytosolic [Formula: see text] oscillations that accompany bursting electrical activity of [Formula: see text]-cells and are physiologically important. ATP-sensitive [Formula: see text] channels (K(ATP) channels) play the key role in setting the overall activity of the cell and in driving bursting, by coupling cell metabolism to the membrane potential. In humans, when there is a defect in K(ATP) channel function, [Formula: see text]-cells fail to respond appropriately to changes in the blood glucose level, and electrical and [Formula: see text] oscillations are lost. However, mice compensate for K(ATP) channel defects in islet [Formula: see text]-cells by employing alternative mechanisms to maintain electrical and [Formula: see text] oscillations. In a recent study, we showed that in mice islets in which K(ATP) channels are genetically knocked out another [Formula: see text] current, provided by inward-rectifying [Formula: see text] channels, is increased. With mathematical modeling, we demonstrated that a sufficient upregulation in these channels can account for the paradoxical electrical bursting and [Formula: see text] oscillations observed in these [Formula: see text]-cells. However, the question of determining the correct level of upregulation that is necessary for this compensation remained unanswered, and this question motivates the current study. [Formula: see text] is a well-known regulator of gene expression, and several examples have been shown of genes that are sensitive to the frequency of the [Formula: see text] signal. In this mathematical modeling study, we demonstrate that a [Formula: see text] oscillation frequency-sensitive gene transcription network can adjust the gene expression level of a compensating [Formula: see text] channel so as to rescue electrical bursting and [Formula: see text] oscillations in a model [Formula: see text]-cell in which the key K(ATP) current is removed. This is done without the prescription of a target [Formula: see text] level, but evolves naturally as a consequence of the feedback between the [Formula: see text]-dependent enzymes and the cell's electrical activity. More generally, the study indicates how [Formula: see text] can provide the link between gene expression and cellular electrical activity that promotes wild-type behavior in a cell following gene knockout.
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Affiliation(s)
- Vehpi Yildirim
- Department of Mathematics, Florida State University, Tallahassee, FL, 32306, USA
| | - Richard Bertram
- Department of Mathematics and Programs in Molecular Biophysics and Neuroscience, Florida State University, Tallahassee, FL, 32306, USA.
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21
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Rorsman P. Review: Insulin secretion: function and therapy of pancreatic beta-cells in diabetes. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/14746514050050040201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
nsulin is secreted from the beta-cells of the pancreatic islets in response to an elevation of blood glucose concentration. This review describes a current view of the metabolic control of insulin secretion and the molecular mechanisms involved, including the role played by the beta-cell to ensure correct release of insulin as a result of electrical signals. It then considers what goes wrong in type 2 diabetes, a disease resulting from insufficient insulin secretion. It focuses on the influence of genetics exploring the theory of a genetic predisposition to type 2 diabetes, as well as the roles played by age and obesity. Finally, the mode of action of the hypoglycaemic sulphonylureas is discussed and the potential implications for the beta-cell associated with a sulphonylurea-based therapy.
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Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology; and Metabolism, Churchill Hospital, University of Oxford, Oxford, OX3 7LJ, UK,
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22
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Han B, Newbould M, Batra G, Cheesman E, Craigie RJ, Mohamed Z, Rigby L, Padidela R, Skae M, Mironov A, Starborg T, Kadler KE, Cosgrove KE, Banerjee I, Dunne MJ. Enhanced Islet Cell Nucleomegaly Defines Diffuse Congenital Hyperinsulinism in Infancy but Not Other Forms of the Disease. Am J Clin Pathol 2016; 145:757-68. [PMID: 27334808 PMCID: PMC4922485 DOI: 10.1093/ajcp/aqw075] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES To quantify islet cell nucleomegaly in controls and tissues obtained from patients with congenital hyperinsulinism in infancy (CHI) and to examine the association of nucleomegaly with proliferation. METHODS High-content analysis of histologic sections and serial block-face scanning electron microscopy were used to quantify nucleomegaly. RESULTS Enlarged islet cell nuclear areas were 4.3-fold larger than unaffected nuclei, and the mean nuclear volume increased to approximately threefold. Nucleomegaly was a normal feature of pediatric islets and detected in the normal regions of the pancreas from patients with focal CHI. The incidence of nucleomegaly was highest in diffuse CHI (CHI-D), with more than 45% of islets containing two or more affected cells. While in CHI-D nucleomegaly was negatively correlated with cell proliferation, in all other cases, there was a positive correlation. CONCLUSIONS Increased incidence of nucleomegaly is pathognomonic for CHI-D, but these cells are nonproliferative, suggesting a novel role in the pathobiology of this condition.
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Affiliation(s)
- Bing Han
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
| | | | | | | | | | - Zainab Mohamed
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust (CMFT), Manchester, UK
| | - Lindsey Rigby
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust (CMFT), Manchester, UK
| | - Raja Padidela
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust (CMFT), Manchester, UK
| | - Mars Skae
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust (CMFT), Manchester, UK
| | - Aleksandr Mironov
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Tobias Starborg
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Karl E Kadler
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Karen E Cosgrove
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Indraneel Banerjee
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust (CMFT), Manchester, UK
| | - Mark J Dunne
- From the Faculty of Life Sciences, University of Manchester, Manchester, UK
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Nessa A, Rahman SA, Hussain K. Hyperinsulinemic Hypoglycemia - The Molecular Mechanisms. Front Endocrinol (Lausanne) 2016; 7:29. [PMID: 27065949 PMCID: PMC4815176 DOI: 10.3389/fendo.2016.00029] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/21/2016] [Indexed: 12/14/2022] Open
Abstract
Under normal physiological conditions, pancreatic β-cells secrete insulin to maintain fasting blood glucose levels in the range 3.5-5.5 mmol/L. In hyperinsulinemic hypoglycemia (HH), this precise regulation of insulin secretion is perturbed so that insulin continues to be secreted in the presence of hypoglycemia. HH may be due to genetic causes (congenital) or secondary to certain risk factors. The molecular mechanisms leading to HH involve defects in the key genes regulating insulin secretion from the β-cells. At this moment, in time genetic abnormalities in nine genes (ABCC8, KCNJ11, GCK, SCHAD, GLUD1, SLC16A1, HNF1A, HNF4A, and UCP2) have been described that lead to the congenital forms of HH. Perinatal stress, intrauterine growth retardation, maternal diabetes mellitus, and a large number of developmental syndromes are also associated with HH in the neonatal period. In older children and adult's insulinoma, non-insulinoma pancreatogenous hypoglycemia syndrome and post bariatric surgery are recognized causes of HH. This review article will focus mainly on describing the molecular mechanisms that lead to unregulated insulin secretion.
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Affiliation(s)
- Azizun Nessa
- Genetics and Genomic Medicine Programme, Department of Paediatric Endocrinology, UCL Institute of Child Health, Great Ormond Street Hospital for Children NHS, London, UK
| | - Sofia A. Rahman
- Genetics and Genomic Medicine Programme, Department of Paediatric Endocrinology, UCL Institute of Child Health, Great Ormond Street Hospital for Children NHS, London, UK
| | - Khalid Hussain
- Genetics and Genomic Medicine Programme, Department of Paediatric Endocrinology, UCL Institute of Child Health, Great Ormond Street Hospital for Children NHS, London, UK
- *Correspondence: Khalid Hussain,
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Senniappan S, Sadeghizadeh A, Flanagan SE, Ellard S, Hashemipour M, Hosseinzadeh M, Salehi M, Hussain K. Genotype and phenotype correlations in Iranian patients with hyperinsulinaemic hypoglycaemia. BMC Res Notes 2015; 8:350. [PMID: 26268944 PMCID: PMC4535259 DOI: 10.1186/s13104-015-1319-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 08/04/2015] [Indexed: 01/19/2023] Open
Abstract
Background Hyperinsulinaemic hypoglycaemia (HH) is a group of clinically and genetically heterogeneous disorders characterized by unregulated insulin secretion. Abnormalities in nine different genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A, UCP2 and HNF1A) have been reported in HH, the most common being ABCC8 and KCNJ11. We describe the genetic aetiology and phenotype of Iranian patients with HH. Methods Retrospective clinical, biochemical and genetic information was collected on 23 patients with biochemically confirmed HH. Mutation analysis was carried out for the ATP-sensitive potassium (KATP) channel genes (ABCC8 and KCNJ11), GLUD1, GCK, HADH and HNF4A. Results 78 % of the patients were identified to have a genetic cause for HH. 48 % of patients had mutation in HADH, whilst ABCC8/KCNJ11 mutations were identified in 30 % of patients. Among the diazoxide-responsive patients (18/23), mutations were identified in 72 %. These include two novel homozygous ABCC8 mutations. Of the five patients with diazoxide-unresponsive HH, three had homozygous ABCC8 mutation, one had heterozygous ABCC8 mutation inherited from an unaffected father and one had homozygous KCNJ11 mutation. 52 % of children in our cohort were born to consanguineous parents. Patients with ABCC8/KCNJ11 mutations were noted to be significantly heavier than those with HADH mutation (p = 0.002). Our results revealed neurodevelopmental deficits in 30 % and epilepsy in 52 % of all patients. Conclusions To the best of our knowledge, this is the first study of its kind in Iran. We found disease-causing mutations in 78 % of HH patients. The predominance of HADH mutation might be due to a high incidence of consanguineous marriage in this population. Further research involving a larger cohort of HH patients is required in Iranian population.
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Affiliation(s)
| | - Atefeh Sadeghizadeh
- Department of Pediatrics, Child Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Sarah E Flanagan
- Institute Biomedical and Clinical Science, University of Exeter Medical School, Exeter, EX2 5DW, UK.
| | - Sian Ellard
- Institute Biomedical and Clinical Science, University of Exeter Medical School, Exeter, EX2 5DW, UK.
| | - Mahin Hashemipour
- Endocrinology and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Majid Hosseinzadeh
- Medical Genetics Laboratory, Alzahra University Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Mansour Salehi
- Pediatric Inherited Disease Research Center (PIDRC), Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Khalid Hussain
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, London, UK. .,Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children, London, UK.
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Abstract
In hyperinsulinemic hypoglycemia (HH) there is dysregulation of insulin secretion from pancreatic β-cells. Insulin secretion becomes inappropriate for the level of blood glucose leading to severe hypoglycemia. HH is associated with a high risk of brain injury because insulin inhibits lipolysis and ketogenesis thus preventing the generation of alternative brain substrates (such as ketone bodies). Hence HH must be diagnosed as soon as possible and the management instituted appropriately to prevent brain damage. This article reviews the mechanisms of glucose physiology in the newborn, the mechanisms of insulin secretion, the etiologic types of HH, and its management.
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Affiliation(s)
- Maria Güemes
- Developmental Endocrinology Research Group, Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Khalid Hussain
- Developmental Endocrinology Research Group, Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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Nessa A, Rahman SA, Hussain K. Molecular mechanisms of congenital hyperinsulinism and prospective therapeutic targets. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1064819] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Roženková K, Güemes M, Shah P, Hussain K. The Diagnosis and Management of Hyperinsulinaemic Hypoglycaemia. J Clin Res Pediatr Endocrinol 2015; 7:86-97. [PMID: 26316429 PMCID: PMC4563192 DOI: 10.4274/jcrpe.1891] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Insulin secretion from pancreatic β-cells is tightly regulated to keep fasting blood glucose concentrations within the normal range (3.5-5.5 mmol/L). Hyperinsulinaemic hypoglycaemia (HH) is a heterozygous condition in which insulin secretion becomes unregulated and its production persists despite low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. The most severe and permanent forms are due to congenital hyperinsulinism (CHI). Recent advances in genetics have linked CHI to mutations in 9 genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A and HNF1A). Histologically, CHI can be divided into 3 types; diffuse, focal and atypical. Given the biochemical nature of HH (non-ketotic), a delay in the diagnosis and management can result in irreversible brain damage. Therefore, it is essential to diagnose and treat HH promptly. Advances in molecular genetics, imaging methods (18F-DOPA PET-CT), medical therapy and surgical approach (laparoscopic surgery) have completely changed the management and improved the outcome of these children. This review provides an overview of the genetic and molecular mechanisms leading to development of HH in children. The article summarizes the current diagnostic methods and management strategies for the different types of CHI.
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Affiliation(s)
| | | | | | - Khalid Hussain
- Great Ormond Street Hospital for Children, UCL Institute of Child Health, Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, London, UK Phone: +44 2079052128 E-mail:
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Jahnavi S, Poovazhagi V, Kanthimathi S, Balamurugan K, Bodhini D, Yadav J, Jain V, Khadgawat R, Sikdar M, Bhavatharini A, Das AK, Kaur T, Mohan V, Radha V. Novel ABCC8 (SUR1) gene mutations in Asian Indian children with congenital hyperinsulinemic hypoglycemia. Ann Hum Genet 2015; 78:311-9. [PMID: 25117148 DOI: 10.1111/ahg.12070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/20/2014] [Indexed: 11/30/2022]
Abstract
Congenital hyperinsulinemic hypoglycemia (HI) is a heterogeneous genetic disorder of insulin secretion characterized by persistent hypoglycemia, most commonly associated with inactivating mutations of the β-cell ATP-sensitive K(+) channel (K(ATP) channel) genes ABCC8 (encoding SUR1) and KCNJ11(encoding Kir6.2). This study aimed to screen the mutations in the genes associated with congenital HI in Asian Indian children. Recessive mutations of these genes cause hyperinsulinism that is unresponsive to treatment with channel agonists like diazoxide. Dominant K(ATP) mutations have been associated with diazoxide-responsive disease. The KCNJ11, ABCC8, GCK, HNF4A, and GLUD1 genes were analyzed by sequence analysis in 22 children with congenital HI. We found 10 novel mutations (c.1delA, c.61delG, c.267delT, c.619-629delCCCGAGGACCT, Gln444*, Leu724Pro, Ala847Thr, Trp898*, IVS30-2A>C, and Leu1454Arg) and two known mutations (Gly111Arg and Arg598*) in the ABCC8 gene. This study describes novel and known ABCC8 gene mutations in children with congenital HI. This is the first large genetic screening study on HI in India and our results will help clinicians in providing optimal treatment for patients with hyperinsulinemia and in assisting affected families with genetic counseling.
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Affiliation(s)
- Suresh Jahnavi
- Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 Diabetes and Dr. Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-Communicable Diseases Prevention & Control, IDF Centre of Education, Gopalapuram, Chennai, India
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Yorifuji T, Masue M, Nishibori H. Congenital hyperinsulinism: global and Japanese perspectives. Pediatr Int 2014; 56:467-76. [PMID: 24865345 DOI: 10.1111/ped.12390] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/12/2014] [Indexed: 12/12/2022]
Abstract
Over the past 20 years, there has been remarkable progress in the diagnosis and treatment of congenital hyperinsulinism (CHI). These advances have been supported by the understanding of the molecular mechanism and the development of diagnostic modalities to identify the focal form of ATP-sensitive potassium channel CHI. Many patients with diazoxide-unresponsive focal CHI have been cured by partial pancreatectomy without developing postsurgical diabetes mellitus. Important novel findings on the genetic basis of the other forms of CHI have also been obtained, and several novel medical treatments have been explored. However, the management of patients with CHI is still far from ideal. First, state-of-the-art treatment is not widely available worldwide. Second, it appears that the management strategy needs to be adjusted according to the patient's ethnic group. Third, optimal management of patients with the diazoxide-unresponsive, diffuse form of CHI is still insufficient and requires further improvement. In this review, we describe the current landscape of this disorder, discuss the racial disparity of CHI using Japanese patients as an example, and briefly note unanswered questions and unmet needs that should be addressed in the near future.
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Affiliation(s)
- Tohru Yorifuji
- Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka, Japan; Clinical Research Center, Osaka City General Hospital, Osaka, Japan; Department of Genetic Medicine, Osaka City General Hospital, Osaka, Japan
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Wang R, Munoz EE, Zhu S, McGrath BC, Cavener DR. Perk gene dosage regulates glucose homeostasis by modulating pancreatic β-cell functions. PLoS One 2014; 9:e99684. [PMID: 24915520 PMCID: PMC4051701 DOI: 10.1371/journal.pone.0099684] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/16/2014] [Indexed: 11/18/2022] Open
Abstract
Background Insulin synthesis and cell proliferation are under tight regulation in pancreatic β-cells to maintain glucose homeostasis. Dysfunction in either aspect leads to development of diabetes. PERK (EIF2AK3) loss of function mutations in humans and mice exhibit permanent neonatal diabetes that is characterized by insufficient β-cell mass and reduced proinsulin trafficking and insulin secretion. Unexpectedly, we found that Perk heterozygous mice displayed lower blood glucose levels. Methodology Longitudinal studies were conducted to assess serum glucose and insulin, intracellular insulin synthesis and storage, insulin secretion, and β-cell proliferation in Perk heterozygous mice. In addition, modulation of Perk dosage specifically in β-cells showed that the glucose homeostasis phenotype of Perk heterozygous mice is determined by reduced expression of PERK in the β-cells. Principal Findings We found that Perk heterozygous mice first exhibited enhanced insulin synthesis and secretion during neonatal and juvenile development followed by enhanced β-cell proliferation and a substantial increase in β-cell mass at the adult stage. These differences are not likely to entail the well-known function of PERK to regulate the ER stress response in cultured cells as several markers for ER stress were not differentially expressed in Perk heterozygous mice. Conclusions In addition to the essential functions of PERK in β-cells as revealed by severely diabetic phenotype in humans and mice completely deficient for PERK, reducing Perk gene expression by half showed that intermediate levels of PERK have a profound impact on β-cell functions and glucose homeostasis. These results suggest that an optimal level of PERK expression is necessary to balance several parameters of β-cell function and growth in order to achieve normoglycemia.
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Affiliation(s)
- Rong Wang
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Elyse E. Munoz
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Siying Zhu
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Barbara C. McGrath
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Douglas R. Cavener
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
- * E-mail:
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Ponmani C, Gannon H, Hussain K, Senniappan S. Paradoxical hypoglycaemia associated with diazoxide therapy for hyperinsulinaemic hypoglycaemia. Horm Res Paediatr 2014; 80:129-33. [PMID: 23886961 DOI: 10.1159/000353773] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/07/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Hyperinsulinaemic hypoglycaemia (HH) is the most common cause of severe and persistent hypoglycaemia in the neonatal period. Diazoxide, a KATP channel activator, is the first line of treatment for patients with HH. METHODS We present 2 cases diagnosed with HH in the neonatal period. Both were started on diazoxide as the first line of treatment and the dose was titrated in order to achieve euglycaemia. RESULTS When the dose of diazoxide was increased to 15 mg/kg/day, we noted that both infants had increased frequency of hypoglycaemic episodes associated with an increase in the intravenous glucose infusion rate required to maintain normoglycaemia. When the diazoxide was stopped, the intravenous glucose infusion rate decreased and the frequency of hypoglycaemic episodes significantly reduced. The period between the increase in the dose of diazoxide and the onset of increased episodes of hypoglycaemia varied from 12 to 48 h. CONCLUSION We report for the first time that diazoxide can cause paradoxical hypoglycaemia when used in moderate to high doses in infants with HH. Our clinical observations support the recent in vitro observations on pancreatic tissue isolated from patients with HH, where diazoxide caused an unanticipated increase in insulin secretion. These observations have important implications for managing patients with HH.
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Affiliation(s)
- Caroline Ponmani
- Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children, NHS Trust, London, UK
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Abstract
ATP-sensitive potassium channels (K(ATP) channels) link cell metabolism to electrical activity by controlling the cell membrane potential. They participate in many physiological processes but have a particularly important role in systemic glucose homeostasis by regulating hormone secretion from pancreatic islet cells. Glucose-induced closure of K(ATP) channels is crucial for insulin secretion. Emerging data suggest that K(ATP) channels also play a key part in glucagon secretion, although precisely how they do so remains controversial. This Review highlights the role of K(ATP) channels in insulin and glucagon secretion. We discuss how K(ATP) channels might contribute not only to the initiation of insulin release but also to the graded stimulation of insulin secretion that occurs with increasing glucose concentrations. The various hypotheses concerning the role of K(ATP) channels in glucagon release are also reviewed. Furthermore, we illustrate how mutations in K(ATP) channel genes can cause hyposecretion or hypersecretion of insulin, as in neonatal diabetes mellitus and congenital hyperinsulinism, and how defective metabolic regulation of the channel may underlie the hypoinsulinaemia and the hyperglucagonaemia that characterize type 2 diabetes mellitus. Finally, we outline how sulphonylureas, which inhibit K(ATP) channels, stimulate insulin secretion in patients with neonatal diabetes mellitus or type 2 diabetes mellitus, and suggest their potential use to target the glucagon secretory defects found in diabetes mellitus.
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Affiliation(s)
- Frances M Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
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Banerjee I, Avatapalle B, Padidela R, Stevens A, Cosgrove KE, Clayton PE, Dunne MJ. Integrating genetic and imaging investigations into the clinical management of congenital hyperinsulinism. Clin Endocrinol (Oxf) 2013; 78:803-13. [PMID: 23347463 DOI: 10.1111/cen.12153] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/03/2013] [Accepted: 01/14/2013] [Indexed: 11/27/2022]
Abstract
Congenital Hyperinsulinism (CHI) is a rare but important cause of hypoglycaemia in infancy. CHI is a heterogeneous disease, but has a strong genetic basis; a number of genetic causes have been identified with CHI in about a third of individuals, chiefly in the genes that code for the ATP sensitive K(+) channels (KATP ) in the pancreatic β-cells. Rapid KATP channel gene testing is a critical early step in the diagnostic algorithm of CHI, with paternal heterozygosity correlating with the occurrence of focal lesions. Imaging investigations to diagnose and localize solitary pancreatic foci have evolved over the last decade with (18)F-DOPA PET-CT scanning as the current diagnostic tool of choice. Although clinical management of CHI has improved significantly with the application of genetic screening and imaging investigations, much remains to be uncovered. This includes a better understanding of the molecular mechanisms for dysregulated insulin release in those patients without known genetic mutations, and the development of biomarkers that could characterize CHI, including long-term prognosis and targeted treatment planning, i.e. 'personalised medicine'. From the perspective of pancreatic imaging, it would be important to achieve greater specificity of diagnosis not only for focal lesions but also for diffuse and atypical forms of the disease.
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Affiliation(s)
- I Banerjee
- Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, UK.
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Kapoor RR, Flanagan SE, Arya VB, Shield JP, Ellard S, Hussain K. Clinical and molecular characterisation of 300 patients with congenital hyperinsulinism. Eur J Endocrinol 2013; 168:557-64. [PMID: 23345197 PMCID: PMC3599069 DOI: 10.1530/eje-12-0673] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Congenital hyperinsulinism (CHI) is a clinically heterogeneous condition. Mutations in eight genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A and HNF1A) are known to cause CHI. AIM To characterise the clinical and molecular aspects of a large cohort of patients with CHI. METHODOLOGY Three hundred patients were recruited and clinical information was collected before genotyping. ABCC8 and KCNJ11 genes were analysed in all patients. Mutations in GLUD1, HADH, GCK and HNF4A genes were sought in patients with diazoxide-responsive CHI with hyperammonaemia (GLUD1), raised 3-hydroxybutyrylcarnitine and/or consanguinity (HADH), positive family history (GCK) or when CHI was diagnosed within the first week of life (HNF4A). RESULTS Mutations were identified in 136/300 patients (45.3%). Mutations in ABCC8/KCNJ11 were the commonest genetic cause identified (n=109, 36.3%). Among diazoxide-unresponsive patients (n=105), mutations in ABCC8/KCNJ11 were identified in 92 (87.6%) patients, of whom 63 patients had recessively inherited mutations while four patients had dominantly inherited mutations. A paternal mutation in the ABCC8/KCNJ11 genes was identified in 23 diazoxide-unresponsive patients, of whom six had diffuse disease. Among the diazoxide-responsive patients (n=183), mutations were identified in 41 patients (22.4%). These include mutations in ABCC8/KCNJ11 (n=15), HNF4A (n=7), GLUD1 (n=16) and HADH (n=3). CONCLUSIONS A genetic diagnosis was made for 45.3% of patients in this large series. Mutations in the ABCC8 gene were the commonest identifiable cause. The vast majority of patients with diazoxide-responsive CHI (77.6%) had no identifiable mutations, suggesting other genetic and/or environmental mechanisms.
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Affiliation(s)
| | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, EX2 5DWUK
| | | | - Julian P Shield
- Department of Child Health, Bristol Royal Hospital for ChildrenBristol, BS2 8BJUK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, EX2 5DWUK
| | - Khalid Hussain
- (Correspondence should be addressed to K Hussain who is now at Molecular Genetics Unit, Developmental Endocrinology Research Group, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK; )
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Faletra F, Athanasakis E, Morgan A, Biarnés X, Fornasier F, Parini R, Furlan F, Boiani A, Maiorana A, Dionisi-Vici C, Giordano L, Burlina A, Ventura A, Gasparini P. Congenital hyperinsulinism: clinical and molecular analysis of a large Italian cohort. Gene 2013; 521:160-5. [PMID: 23506826 DOI: 10.1016/j.gene.2013.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/07/2013] [Indexed: 11/15/2022]
Abstract
Congenital hyperinsulinism (CHI) is a genetic disorder characterized by profound hypoglycemia related to an inappropriate insulin secretion. It is a heterogeneous disease classified into two major subgroups: "channelopathies" due to defects in ATP-sensitive potassium channel, encoded by ABCC8 and KCNJ11 genes, and "metabolopathies" caused by mutation of several genes (GLUD1, GCK, HADH, SLC16A1, HNF4A and HNF1A) and involved in different metabolic pathways. To elucidate the genetic etiology of CHI in the Italian population, we conducted an extensive sequencing analysis of the CHI-related genes in a large cohort of 36 patients: Twenty-nine suffering from classic hyperinsulinism (HI) and seven from hyperinsulinism-hyperammonemia (HI/HA). Seventeen mutations have been found in fifteen HI patients and five mutations in five HI/HA patients. Our data confirm the major role of ATP-sensitive potassium channel in the pathogenesis of Italian cases (~70%) while the remaining percentage should be attributed to other. A better knowledge of molecular basis of CHI would lead to improve strategies for genetic screening and prenatal diagnosis. Moreover, genetic analysis might also help to distinguish the two histopathological forms of CHI, which would lead to a clear improvement in the treatment and in genetic counseling.
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Affiliation(s)
- Flavio Faletra
- Institute for Maternal and Child Health-IRCCS "Burlo Garofolo", Trieste, Italy.
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Zaydman MA, Silva JR, Cui J. Ion channel associated diseases: overview of molecular mechanisms. Chem Rev 2012; 112:6319-33. [PMID: 23151230 DOI: 10.1021/cr300360k] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mark A Zaydman
- Department of Biomedical Engineering, Washington University, Saint Louis, Missouri 63130, United States
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Abstract
Hyperglycaemia has multiple effects on β-cells, some clearly prosecretory, including hyperplasia and elevated insulin content, but eventually, a 'glucotoxic' effect which leads to pancreatic β-cell dysfunction, reduced β-cell mass and insulin deficiency, is an important part of diabetes pathophysiology. Myriad underlying cellular and molecular processes could lead to such dysfunction. High glucose will stimulate glycolysis and oxidative phosphorylation, which will in turn increase β-cell membrane excitability through K(ATP) channel closure. Chronic hyperexcitability will then lead to persistently elevated [Ca(2+)](i), a key trigger to insulin secretion. Thus, at least a part of the consequence of 'hyperstimulation' by glucose has been suggested to be a result of 'hyperexcitability' and chronically elevated [Ca(2+)](i). This link is lost when the [glucose], K(ATP) -channel activity link is broken, either pharmacologically or genetically. In isolated islets, such studies reveal that hyperexcitability causes a largely reversible chronic loss of insulin content, but in vivo chronic hyperexcitability per se does not lead to β-cell death or loss of insulin content. On the other hand, chronic inexcitability in vivo leads to systemic diabetes and consequential β-cell death, even while [Ca(2+)](i) remains low.
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Affiliation(s)
- C G Nichols
- Department of Cell Biology and Physiology and Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Senniappan S, Shanti B, James C, Hussain K. Hyperinsulinaemic hypoglycaemia: genetic mechanisms, diagnosis and management. J Inherit Metab Dis 2012; 35:589-601. [PMID: 22231386 DOI: 10.1007/s10545-011-9441-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/06/2011] [Accepted: 12/13/2011] [Indexed: 10/14/2022]
Abstract
Hyperinsulinaemic hypoglycaemia (HH) is due to the unregulated secretion of insulin from pancreatic β-cells. A rapid diagnosis and appropriate management of these patients is essential to prevent the potentially associated complications like epilepsy, cerebral palsy and neurological impairment. The molecular basis of HH involves defects in key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A and UCP2) which regulate insulin secretion. The most severe forms of HH are due to loss of function mutations in ABCC8/KCNJ11 which encode the SUR1 and KIR6.2 components respectively of the pancreatic β-cell K(ATP) channel. At a histological level there are two major forms (diffuse and focal) each with a different genetic aetiology. The diffuse form is inherited in an autosomal recessive (or dominant) manner whereas the focal form is sporadic in inheritance and is localised to a small region of the pancreas. The focal form can now be accurately localised pre-operatively using a specialised positron emission tomography scan with the isotope Fluroine-18L-3, 4-dihydroxyphenyalanine (18F-DOPA-PET). Focal lesionectomy can provide cure from the hypoglycaemia. However the diffuse form is managed medically or by near total pancreatectomy (with high risk of diabetes mellitus). Recent advances in molecular genetics, imaging with 18F-DOPA-PET/CT and novel surgical techniques have changed the clinical approach to patients with HH.
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Affiliation(s)
- Senthil Senniappan
- Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children NHS Trust WC1N 3JH and Institute of Child Health, University College London, London, WC1N 1EH, UK
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Glaser B. Lessons in human biology from a monogenic pancreatic β cell disease. J Clin Invest 2011; 121:3821-5. [PMID: 21968108 DOI: 10.1172/jci60002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Deciphering the complexities of human β cell physiology is critical to our understanding of the pathophysiology behind both type 1 and type 2 diabetes. One way to do this is to study individuals with congenital hyperinsulinism (CHI), a rare genetic disease characterized by dysregulation of insulin secretion resulting in hypoglycemia. In this issue of the JCI, Henquin et al. report in vitro studies of pancreatic tissue obtained from CHI patients during therapeutic pancreatectomy that have yielded exciting new insights into human β cell physiology. The data validate and extend observations made in model organisms.
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Affiliation(s)
- Benjamin Glaser
- Endocrinology and Metabolism Service, Internal Medicine Department, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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Henquin JC, Nenquin M, Sempoux C, Guiot Y, Bellanné-Chantelot C, Otonkoski T, de Lonlay P, Nihoul-Fékété C, Rahier J. In vitro insulin secretion by pancreatic tissue from infants with diazoxide-resistant congenital hyperinsulinism deviates from model predictions. J Clin Invest 2011; 121:3932-42. [PMID: 21968111 DOI: 10.1172/jci58400] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 07/13/2011] [Indexed: 01/25/2023] Open
Abstract
Congenital hyperinsulinism (CHI) is the major cause of persistent neonatal hypoglycemia. CHI most often occurs due to mutations in the ABCC8 (which encodes sulfonylurea receptor 1) or KCNJ11 (which encodes the potassium channel Kir6.2) gene, which result in a lack of functional KATP channels in pancreatic β cells. Diffuse forms of CHI (DiCHI), in which all β cells are abnormal, often require subtotal pancreatectomy, whereas focal forms (FoCHI), which are characterized by localized hyperplasia of abnormal β cells, can be cured by resection of the lesion. Here, we characterized the in vitro kinetics of insulin secretion by pancreatic fragments from 6 DiCHI patients and by focal lesion and normal adjacent pancreas from 18 FoCHI patients. Responses of normal pancreas were similar to those reported for islets from adult organ donors. Compared with normal pancreas, basal insulin secretion was elevated in both FoCHI and DiCHI tissue. Affected tissues were heterogeneous in their secretory responses, with increased glucose levels often producing a rapid increase in insulin secretion that could be followed by a paradoxical decrease below prestimulatory levels. The KATP channel blocker tolbutamide was consistently ineffective in stimulating insulin secretion; conversely, the KATP channel activator diazoxide often caused an unanticipated increase in insulin secretion. These observed alterations in secretory behavior were similar in focal lesion and DiCHI tissue, and independent of the specific mutation in ABCC8 or KCNJ11. They cannot be explained by classic models of β cell function. Our results provide insight into the excessive and sometimes paradoxical changes in insulin secretion observed in CHI patients with inactivating mutations of KATP channels.
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Affiliation(s)
- Jean-Claude Henquin
- Unit of Endocrinology and Metabolism, Faculty of Medicine, University of Louvain, Brussels, Belgium.
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Bruederle CE, Gay J, Shyng SL. A role of the sulfonylurea receptor 1 in endocytic trafficking of ATP-sensitive potassium channels. Traffic 2011; 12:1242-56. [PMID: 21649805 DOI: 10.1111/j.1600-0854.2011.01227.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ATP-sensitive potassium (K(ATP) ) channel consisting of sulfonylurea receptor 1 (SUR1) and inward-rectifier potassium channel 6.2 (Kir6.2) has a well-established role in insulin secretion. Mutations in either subunit can lead to disease due to aberrant channel gating, altered channel density at the cell surface or a combination of both. Endocytic trafficking of channels at the plasma membrane is one way to influence surface channel numbers. It has been previously reported that channel endocytosis is dependent on a tyrosine-based motif in Kir6.2, while SUR1 alone is unable to internalize. In this study, we followed endocytic trafficking of surface channels in real time by live-cell imaging of channel subunits tagged with an extracellular minimal α-bungarotoxin-binding peptide labeled with a fluorescent dye. We show that SUR1 undergoes endocytosis independent of Kir6.2. Moreover, mutations in the putative endocytosis motif of Kir6.2, Y330C, Y330A and F333I are unable to prevent channel endocytosis. These findings challenge the notion that Kir6.2 bears the sole endocytic signal for K(ATP) channels and support a role of SUR1 in this trafficking process.
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Affiliation(s)
- Cathrin E Bruederle
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA.
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Powell PD, Bellanné-Chantelot C, Flanagan SE, Ellard S, Rooman R, Hussain K, Skae M, Clayton P, de Lonlay P, Dunne MJ, Cosgrove KE. In vitro recovery of ATP-sensitive potassium channels in β-cells from patients with congenital hyperinsulinism of infancy. Diabetes 2011; 60:1223-8. [PMID: 21411514 PMCID: PMC3064095 DOI: 10.2337/db10-1443] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Congenital hyperinsulinism in infancy (CHI) is characterized by unregulated insulin secretion from pancreatic β-cells; severe forms are associated with defects in ABCC8 and KCNJ11 genes encoding sulfonylurea receptor 1 (SUR1) and Kir6.2 subunits, which form ATP-sensitive K(+) (K(ATP)) channels in β-cells. Diazoxide therapy often fails in the treatment of CHI and may be a result of reduced cell surface expression of K(ATP) channels. We hypothesized that conditions known to facilitate trafficking of cystic fibrosis transmembrane regulator (CFTR) and other proteins in recombinant expression systems might increase surface expression of K(ATP) channels in native CHI β-cells. RESEARCH DESIGN AND METHODS Tissue was isolated during pancreatectomy from eight patients with CHI and from adult cadaver organ donors. Patients were screened for mutations in ABCC8 and KCNJ11. Isolated β-cells were maintained at 37°C or 25°C and in the presence of 1) phorbol myristic acid, forskolin and 3-isobutyl-1-methylxanthine, 2) BPDZ 154, or 3) 4-phenylbutyrate. Surface expression of functional channels was assessed by patch-clamp electrophysiology. RESULTS Mutations in ABCC8 were detected for all patients tested (n = 7/8) and included three novel mutations. In five of eight patients, no changes in K(ATP) channel activity were observed under different cell culture conditions. However, in three patients, in vitro recovery of functional K(ATP) channels occurred. Here, we report the first cases of recovery of defective K(ATP) channels in human β-cells using modified cell culture conditions. CONCLUSIONS Our study establishes the principle that chemical modification of K(ATP) channel subunit trafficking could be of benefit for the future treatment of CHI.
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Affiliation(s)
| | | | - Sarah E. Flanagan
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Raoul Rooman
- Department of Pediatrics, Antwerp University Hospital, Universiteitsplein 1, Wilrijk, Antwerp, Belgium
| | - Khalid Hussain
- Institute of Child Health, Great Ormond Street Hospital, London, U.K
| | - Mars Skae
- Department of Endocrinology, Royal Manchester Children's Hospital, Manchester, U.K
| | - Peter Clayton
- Department of Endocrinology, Royal Manchester Children's Hospital, Manchester, U.K
| | - Pascale de Lonlay
- Hôpital Necker Enfants Malades, Reference Centre of Metabolic Diseases, Faculté de Médecine, Paris, France
| | - Mark J. Dunne
- Faculty of Life Sciences, University of Manchester, Manchester, U.K
| | - Karen E. Cosgrove
- Faculty of Life Sciences, University of Manchester, Manchester, U.K
- Corresponding author: Karen E. Cosgrove,
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Vieira TC, Bergamin CS, Gurgel LC, Moisés RS. Hyperinsulinemic hypoglycemia evolving to gestational diabetes and diabetes mellitus in a family carrying the inactivating ABCC8 E1506K mutation. Pediatr Diabetes 2010; 11:505-8. [PMID: 20042013 DOI: 10.1111/j.1399-5448.2009.00626.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Congenital hyperinsulinism of infancy (CHI) is the most common cause of hypoglycemia in newborns and infants. Several molecular mechanisms are involved in the development of CHI, but the most common genetic defects are inactivating mutations of the ABCC8 or KCNJ11 genes. The classical treatment for CHI has been pancreatectomy that eventually leads to diabetes. More recently, conservative treatment has been attempted in some cases, with encouraging results. Whether or not the patients with heterozygous ABCC8 mutations submitted to conservative treatment may spontaneously develop type 2 diabetes in the long run, is a controversial issue. Here, we report a family carrying the dominant heterozygous germ line E1506K mutation in ABCC8 associated with persistent hypoglycemia in the newborn period and diabetes in adulthood. The mutation occurred as a de novo germ line mutation in the mother of the index patient. Her hypoglycemic symptoms as a child occurred after the fourth year of life and were very mild, but she developed glucose metabolism impairment in adulthood. On the other hand, in her daughter, the clinical manifestations of the disease occurred in the neonatal period and were more severe, leading to episodes of tonic-clonic seizures that were well controlled with octreotide or diazoxide. Our data corroborate the hypothesis that the dominant E1506K ABCC8 mutation, responsible for CHI, predisposes to the development of glucose intolerance and diabetes later in life.
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Affiliation(s)
- Teresa C Vieira
- Division of Endocrinology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
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Hyperinsulinism and diabetes: genetic dissection of beta cell metabolism-excitation coupling in mice. Cell Metab 2009; 10:442-53. [PMID: 19945402 PMCID: PMC3245718 DOI: 10.1016/j.cmet.2009.10.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 10/13/2009] [Accepted: 10/27/2009] [Indexed: 12/24/2022]
Abstract
The role of metabolism-excitation coupling in insulin secretion has long been apparent, but in recent years, in parallel with studies of human hyperinsulinism and diabetes, genetic manipulation of proteins involved in glucose transport, metabolism, and excitability in mice has brought the central importance of this pathway into sharp relief. We focus on these animal studies and how they provide important insights into not only metabolic and electrical regulation of insulin secretion, but also downstream consequences of alterations in this pathway and the etiology and treatment of insulin-secretion diseases in humans.
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Kapoor RR, James C, Hussain K. Advances in the diagnosis and management of hyperinsulinemic hypoglycemia. ACTA ACUST UNITED AC 2009; 5:101-12. [PMID: 19165222 DOI: 10.1038/ncpendmet1046] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 11/12/2008] [Indexed: 12/16/2022]
Abstract
Hyperinsulinemic hypoglycemia (HH) is a consequence of unregulated insulin secretion by pancreatic beta-cells and is a major cause of hypoglycemic brain injury and mental retardation. Congenital HH is caused by mutations in genes involved in regulation of insulin secretion, seven of which have been identified (ABCC8, KCNJ11, GLUD1, CGK, HADH, SLC16A1 and HNF4A). Severe forms of congenital HH are caused by mutations in ABCC8 and KCNJ11, which encode the two components of the pancreatic beta-cell ATP-sensitive potassium channel. Mutations in HNF4A, GLUD1, CGK, and HADH lead to transient or persistent HH, whereas mutations in SLC16A1 cause exercise-induced HH. Rapid genetic analysis combined with an understanding of the histological features (focal or diffuse disease) of congenital HH and the introduction of (18)F-L-3,4-dihydroxyphenylalanine PET-CT to guide laparoscopic surgery have totally transformed the clinical approach to this complex disease. Adult-onset HH is mostly caused by an insulinoma; however, it has also been reported to present as postprandial HH in patients with noninsulinoma pancreatogenous hypoglycemia syndrome, in those who have undergone gastric-bypass surgery for morbid obesity, and in those with mutations in the insulin-receptor gene.
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Affiliation(s)
- Ritika R Kapoor
- Institute of Child Health, University College London and Great Ormond Street Hospital for Children National Health Services Trust, London, UK
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Kim JS, Zheng H, Kim SJ, Park JW, Park KS, Ho WK, Chun YS. Role of aryl hydrocarbon receptor nuclear translocator in KATP channel-mediated insulin secretion in INS-1 insulinoma cells. Biochem Biophys Res Commun 2009; 379:1048-53. [PMID: 19141293 DOI: 10.1016/j.bbrc.2009.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Accepted: 01/05/2009] [Indexed: 11/16/2022]
Abstract
Aryl hydrocarbon receptor nuclear translocator (ARNT) has been known to participate in cellular responses to xenobiotic and hypoxic stresses, as a common partner of aryl hydrocarbon receptor and hypoxia inducible factor-1/2alpha. Recently, it was reported that ARNT is essential for adequate insulin secretion in response to glucose input and that its expression is downregulated in the pancreatic islets of diabetic patients. In the present study, the authors addressed the mechanism by which ARNT regulates insulin secretion in the INS-1 insulinoma cell line. In ARNT knock-down cells, basal insulin release was elevated, but insulin secretion was not further stimulated by a high-glucose challenge. Electrophysiological analyses revealed that glucose-dependent membrane depolarization was impaired in these cells. Furthermore, K(ATP) channel activity and expression were reduced. Of two K(ATP) channel subunits, Kir6.2 was found to be positively regulated by ARNT at the mRNA and protein levels. Based on these results, the authors suggest that ARNT expresses K(ATP) channel and by so doing regulates glucose-dependent insulin secretion.
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Affiliation(s)
- Ji-Seon Kim
- Department of Physiology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799, Republic of Korea
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Valayannopoulos V, Romano S, Mention K, Vassault A, Rabier D, Polak M, Robert JJ, de Keyzer Y, de Lonlay P. What's new in metabolic and genetic hypoglycaemias: diagnosis and management. Eur J Pediatr 2008; 167:257-65. [PMID: 17912550 DOI: 10.1007/s00431-007-0600-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Accepted: 08/23/2007] [Indexed: 11/25/2022]
Abstract
Hypoglycaemia in children can be a life-threatening situation that needs to be assessed rigorously in order to treat efficiently and avoid relapse that can be responsible for cerebral damage. The diagnosis of impairment in glucose homeostasis requires the knowledge of the mechanisms regulating blood glucose concentration. The clinical history and presentation, when available, especially the timing of hypoglycaemia with respect to the last meal and some simple clinical and biological tests may allow diagnosing the vast majority of patients presenting with hypoglycaemia. Recently, new metabolic and endocrinologic genetic causes of hypoglycaemia have been identified that may give new insight to the complex mechanisms of glucose regulation and thus contribute to the discovery of new genes regulating glucose homeostasis. New diagnostic tests such as the 18-fluoro-Dopa PET-scan have also been recently developed.
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Affiliation(s)
- Vassili Valayannopoulos
- Metabolic Department and Reference Centre for Metabolic Diseases, Necker-Enfants Malades Hospital, 149, Rue des Sèvres, 75015 Paris, France,
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Hussain K. Diagnosis and Management of Hyperinsulinaemic Hypoglycaemia of Infancy. Horm Res Paediatr 2007; 69:2-13. [PMID: 18059080 DOI: 10.1159/000111789] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 07/27/2007] [Indexed: 11/19/2022] Open
Affiliation(s)
- Khalid Hussain
- London Centre for Paediatric Endocrinology and Metabolism, Great Ormond Street Hospital for Children NHS Trust, Institute of Child Health, University College London, London, UK.
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Webb MA, Platton SL, Dennison AR, James RFL. Immunohistochemical evidence that culture in the high aspect rotating vessel can up-regulate hormone expression in growth dedifferentiated PHHI-derived islet cells. In Vitro Cell Dev Biol Anim 2007; 43:210-4. [PMID: 17846858 DOI: 10.1007/s11626-007-9046-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 06/01/2007] [Indexed: 10/22/2022]
Abstract
Islet cells derived from patients with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) have the ability to grow readily in simple culture media. However, as with primary islets and cell lines, they lose hormone expression upon growth. In this study, we have investigated the role of three-dimensional cell-to-cell contact in the reinitiation of hormone expression in growth dedifferentiated PHHI-derived cells. Two main methods of cell aggregation were studied; the promotion of pseudoislets through petri dish culture and the creation of cell aggregates in the microgravity environment of the high aspect ratio vessel (HARV). Immunohistochemical analysis and ELISA assay showed that petri dish culture did not re-establish endocrine expression in any of the five cultures tested. However, through HARV technology, we have demonstrated that it is possible to reactivate insulin, glucagon, somatostatin, and GAD expression in PHHI-derived cells that had previously stopped expressing these markers. These results indicate that the unique environment of the HARV can be conducive to the upregulation of endocrine expression of islet-derived cells and optimization of culture conditions may prove useful in the sphere of beta cell proliferation.
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Affiliation(s)
- M'Balu A Webb
- Department of Hepatobiliary Surgery, Leicester General Hospital, Gwendolen Road, Leicester, UK.
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Muzyamba M, Farzaneh T, Behe P, Thomas A, Christesen HBT, Brusgaard K, Hussain K, Tinker A. Complex ABCC8 DNA variations in congenital hyperinsulinism: lessons from functional studies. Clin Endocrinol (Oxf) 2007; 67:115-24. [PMID: 17466004 DOI: 10.1111/j.1365-2265.2007.02847.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Congenital hyperinsulinism (CHI) is a cause of persistent and severe hypoglycaemia in infancy. Mutations in the genes ABCC8 and KCNJ11 encoding SUR1 and Kir6.2, respectively, are the commonest cause of CHI. We investigated whether the possession of two DNA variants leading to coding changes in a single allele of ABCC8 can affect the potential mechanism of disease pathogenesis. DESIGN AND PATIENTS We studied two patients with complex mutations in the ABCC8 gene with CHI and used in vitro studies to explore the potential disease mechanism and the contribution of the various mutant allelles. RESULTS The first case had diffuse disease and was homozygous for the mutations D1193V and R1436Q in SUR1. Channel complexes containing the D1193V mutant were delivered to the plasma membrane and were functional and those containing R1436Q were also present at the plasma membrane but were nonfunctional. Combining the two mutations (SUR1D1193V/R1436Q) led to intracellular retention of the channel complex. In a second family, the patient had histologically focal disease and was heterozygous for two mutations from his father (G228D and D1471N) and one from his mother (V1572I). SUR1 G228D and D1471N singly or in combination led to intracellular retention of the channel complex and loss of function. By contrast, V1572I is trafficked appropriately and is functional, consistent with a mechanism of reduction to hemizygosity of paternal ABCC8 in focal disease. V1572I is likely to be a benign DNA variant. CONCLUSION In one patient the combination of two coding variants led to intracellular retention of channel complex. In a second patient, functional studies allowed us to unravel the DNA variants likely to be causing the abrogation of ATP-sensitive K(+) channel function.
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Affiliation(s)
- Morris Muzyamba
- BHF Laboratories and Department of Medicine, University College London, London, UK
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