The Comparative Anatomy of Islets

Heller, R. Scott

doi:10.1007/978-90-481-3271-3_2

Cited by 25 publications

(11 citation statements)

References 70 publications

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“…In contrast, in some fish, rodents, and amphibians, the β-cells are clustered into the center of the islet with glucagon and somatostatin-positive cells on the mantle. 14 The data presented here along with a recent publication from another lab 9 challenge the concept that all human islets have the same basic architecture. Rather, islets fall into two general categories based on their diameter and other morphological features.…”

Section: Discussionmentioning

confidence: 56%

“…As described eloquently by Heller, human islets have many distinct features when compared with islets of other species. 14 Heller explained that in humans and non-human primates the endocrine cells are arranged in a relatively random organization. In contrast, in some fish, rodents, and amphibians, the β-cells are clustered into the center of the islet with glucagon and somatostatin-positive cells on the mantle.…”

Section: Discussionmentioning

confidence: 99%

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Small human islets comprised of moreβ-cells with higher insulin content than large islets

Farhat

Almelkar

Ramachandran

et al. 2013

Islets

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For the past 30 y, data have suggested that unique islet populations exist, based on morphology and glucose sensitivity. Yet little has been done to determine the mechanism of these functional differences. The purpose of this study was to determine whether human islets were comprised functionally unique populations, and to elucidate a possible mechanism. Islets or pancreatic sections from 29 human donors were analyzed. Islets were isolated and measured for insulin secretion, cell composition and organization, insulin and glucagon granule density and insulin content. Insulin secretion was significantly greater in small compared with large islets. In sectioned human pancreata, β-cells comprised a higher proportion of the total endocrine cells in small islets (63%) than large islets (39%). A higher percentage of β-cells in small islets contacted blood vessels (44%) compared with large islets (31%). Total insulin content of isolated human islets was significantly greater in the small (1323 ± 512 μIU/IE) compared with large islets (126 ± 48 μIU/IE). There was less immunostaining for insulin in the large islets from human pancreatic sections, especially in the core of the islet, compared with small islets. The results suggest that differences in insulin secretion between large and small islets may be due to a higher percentage of β-cells in small islets with more β-cells in contact with blood vessels and a higher concentration of insulin/β-cell in small islets.

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Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Small human islets comprised of moreβ-cells with higher insulin content than large islets

Farhat

Almelkar

Ramachandran

et al. 2013

Islets

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show abstract

“…A comprehensive review by Heller noted that the first examples of an islet-like organ containing three distinct endocrine cell types emerged in cartilaginous and bony fish. Later, amphibians and reptiles evolved islets with four major endocrine hormones, and in some but not all mammalian species, islets with all five cell types can be observed (Heller, 2010). We propose that the establishment of hybrid-cell populations may represent an intermediate stage along the diversification and evolution of the discrete subsets of endocrine cells.…”

Section: Hybrid Cells and The Evolution Of Endocrine Cell Typesmentioning

confidence: 86%

A single-cell atlas of de novo β-cell regeneration reveals the contribution of hybrid β/δ-cells to diabetes recovery in zebrafish

et al. 2022

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Regeneration-competent species possess the ability to reverse the progression of severe diseases by restoring the function of the damaged tissue. However, the cellular dynamics underlying this capability remain unexplored. Here, we have used single-cell transcriptomics to map de novo β-cell regeneration during induction and recovery from diabetes in zebrafish. We show that the zebrafish has evolved two distinct types of somatostatin-producing δ-cells, which we term δ1- and δ2-cells. Moreover, we characterize a small population of glucose-responsive islet cells, which share the hormones and fate-determinants of both β- and δ1-cells. The transcriptomic analysis of β-cell regeneration reveals that β/δ hybrid cells provide a prominent source of insulin expression during diabetes recovery. Using in vivo calcium imaging and cell tracking, we further show that the hybrid cells form de novo and acquire glucose-responsiveness in the course of regeneration. The overexpression of dkk3, a gene enriched in hybrid cells, increases their formation in the absence of β-cell injury. Finally, interspecies comparison shows that plastic δ1-cells are partially related to PP cells in the human pancreas. Our work provides an atlas of β-cell regeneration and indicates that the rapid formation of glucose-responsive hybrid cells contributes to the resolution of diabetes in zebrafish

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“…Worms and protochordates have gut cells that produce insulin-like peptides, whereas Drosophila have similar peptide-producing cells in the pars intracerebralis of the brain 3 . Among vertebrates, the hagfish, which has insulin-producing cells near the bile duct, is the most primitive to have a pancreas-like structure.…”

Section: Establishing Identity: Evolution Of the Pancreasmentioning

confidence: 99%

Control of Cell Identity in Pancreas Development and Regeneration

2013

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The endocrine and exocrine cells in the adult pancreas are not static, but can change differentiation state in response to injury or stress. This concept of cells in flux means that there may be ways to generate certain types of cells (such as insulin-producing β-cells) and prevent formation of others (such as transformed, neoplastic cells). We review different aspects of cell identity in the pancreas, discussing how cells achieve their identity during embryonic development and maturation, and how this identity remains plastic, even in the adult pancreas.

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The Comparative Anatomy of Islets

Cited by 25 publications

References 70 publications

Small human islets comprised of moreβ-cells with higher insulin content than large islets

Small human islets comprised of moreβ-cells with higher insulin content than large islets

A single-cell atlas of de novo β-cell regeneration reveals the contribution of hybrid β/δ-cells to diabetes recovery in zebrafish

Control of Cell Identity in Pancreas Development and Regeneration

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