Elsevier

Biochimie

Volume 143, December 2017, Pages 29-32
Biochimie

Mini-review
Autonomic nervous system and pancreatic islet blood flow

https://doi.org/10.1016/j.biochi.2017.10.001Get rights and content

Highlights

  • New imaging tools led to a better definition of islet's innervation and vasculature.

  • Parasympathetic activity is a major regulator of islet blood flow.

  • Dysregulated islet blood flow is observed in diabetes and/or obesity.

  • These dysregulations are sustained by changes in autonomic nervous system activity.

Abstract

Vascularization and innervation of the islet of Langerhans are highly interconnected and are critical for intercellular and intertissular communication. They are both involved in the control of islet blood flow which has been shown to have an important role in the control of endocine secretion. Both parameters are disturbed during the course of metabolic pathologies and particularly diabetes. A better understanding of these mechanisms has and will greatly benefit from the rapidly-emerging technologies particularly in vivo imaging enabling to study both anatomy and functions of the islet.

Introduction

Since the original observation of Langerhans, numerous studies have confirmed a rich and dense innervation of endocrine pancreas. Sympathetic (splanchnic nerve) and parasympathetic (vagus nerve) fibres are directly connected to the islets of Langerhans an in such they modulate hormonal secretion and particularly insulin secretion [1], [2], [3].

The autonomic nervous system can also participate to the control of insulin secretion indirectly via the regulation of pancreatic and islet blood flow [4]. This is achieved via 1) the delivery of nutrients and/or other circulating factors involved in the regulation of insulin secretion and 2) the dispersion of insulin itself in the blood stream.

The aim of the present paper is to briefly review data obtained during the last years focusing on both innervation and vascularization of the islet and the role of islet blood flow in insulin secretion in normal and pathological conditions, thanks to new techniques especially imaging one.

Section snippets

Islet innervation and vascularization

Vascularization and innervation of the endocrine pancreas are highly entangled and interconnected and are critical for intercellular and intertissular communication. Although the main effect of the nervous system is the regulation of pancreatic hormones secretion, an important role of parasympathetic activity is the stimulation of endocrine cell proliferation whereas recent data demonstrate the involvement of sympathetic innervation in the islet architecture [5], [6], [7].

Till recently due to

Islet blood flow and influence of the ANS

Islet blood flow is one of the important component of islet activity as assumed and demonstrated by the pioneer observation of Claes Hellerstrom in the sixties and its followers particularly Leif Jansson in the eighties [28], [29]. The techniques used to measure islet blood flow evolved over the years. Starting with quantification by the number of erythrocytes in the islets, flow deposition coupled or not with radiological techniques and since some years various and more and more sophisticated

Changes in pathological conditions

Anatomical studies report remodelling of both microvasculature and innervation in animal models of type 1 and 2 diabetes [26], [32]. As consequence or cause what remains to be demonstrated, there is evidence for dysregulated islet blood flow in metabolic pathologies such as diabetes and/or obesity [14]. Islet hyperperfusion has been reported in most animal models of diabetes and obesity, e.g., obese hyperglycemic (ob/ob) mice [39], lean type 2 diabetic GK rats [40], [41] or after neonatal

Conclusion

More and more data have been accumulated over the years leading to a better understanding of islet morphology and particularly the way they are both vascularized and innervated. However, there are still many shadows that need to be enlightened. Among them one can underline the deciphering of 1) the exact role of the sympathetic nervous system in pancreatic endocrine function; 2) the differences that might exist between animal models and humans; 3) whether dysregulated islet blood flow

Conflict of interest

The author declares no conflict of interest.

Acknowledgments

This work has been made possible by the continuous support of the Centre National de la Recherche Scientifique (CNRS-France).

References (46)

  • B. Thorens

    Neural regulation of pancreatic islet cel mass and function

    Diabetes Obes. Meta

    (2014)
  • T. Kiba

    Relationships between the autonomic nervous system and the pancreas including regulation of regeneration and apoptosis: recent development

    Pancreas

    (2004)
  • D. Zhu

    Recent progress in tissue optical clearing

    Laser Phot. Rev.

    (2013)
  • Y.Y. Fu

    Three-dimensional optical method for integrated visualization of mouse islet microstructure and vascular network with subcellular-level resolution

    J. Biomed. Opt.

    (2010)
  • S.C. Tang

    Vascular labeling of luminescent gold nanorods enables 3-D microscopy of mouse intestinal capillaries

    ACS Nano

    (2010)
  • C. Berclaz

    Label-free fat 3D coherent imaging reveals pancreatic islest micro-vascularization and dynamic blood flow

    Biomed. Opt. Express

    (2016)
  • C.H. Dai

    Pancreatic islet vasculature adapts to insulin resistance through dilatation and not angiogenesis

    Diabetes

    (2013)
  • N. Baillan et al.

    Islet vasculature as a regulator of endocrine pancreas function

    World J. Surg.

    (2007)
  • P. In't Veld et al.

    Microscopic anatomy of the human islet of Langerhans

    Adv. Exp. Med. Biol.

    (2010)
  • J. Dolenšek et al.

    Structural similarities and differences between the human and the mouse pancreas

    Islets

    (2015)
  • L. Jansson

    Pancreatic islet blood flow and its measurement

    Ups. J. Med. Sci.

    (2016)
  • L.R. Nyman

    Realtime, multidimensional in vivo imaging used to investigate blood flow in mouse pancreatic islets

    J. Clin. Invest

    (2008)
  • L.R. Nyman

    Glucose-dependent blood flow dynamics in murine pancreatic islets in vivo

    Am. J. Physiol. Endocrinol. Metab.

    (2010)
  • Cited by (12)

    • Exposure to intrauterine diabetes and post-natal high-fat diet: Effects on the endocrine pancreas of adult rat female pups

      2022, Life Sciences
      Citation Excerpt :

      However, studies involving an HFD and/or maternal hyperglycemia for somatostatin determination are still scarce in the literature, which makes this study unpublished and relevant regarding immunostaining for the triad in the pancreatic islets of adult rats damaged by the two insults. Sympathetic and parasympathetic systems innervate pancreatic islets [28], and regulate glucose homeostasis [29]. The sympathetic input on the endocrine pancreas stimulates glucagon secretion and inhibits insulin release, whereas parasympathetic fibers stimulate both glucagon and insulin secretion [30].

    • The pancreatic islet: What we know 150 years after Langerhans

      2019, Bulletin de l'Academie Nationale de Medecine
    View all citing articles on Scopus
    View full text