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In vivo Ca 2+ dynamics in single pancreatic β cells
Author(s) -
Jacob Stefan,
Köhler Martin,
Tröster Philip,
Visa Montse,
GarcíaPrieto Concha F.,
Alanentalo Tomas,
Moede Tilo,
Leibiger Barbara,
Leibiger Ingo B.,
Berggren PerOlof
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201901302rr
Subject(s) - in vivo , population , cell , glucose homeostasis , pancreas , chemistry , endocrinology , biology , medicine , microbiology and biotechnology , insulin , biochemistry , insulin resistance , environmental health
The dynamics of cytoplasmic free Ca 2+ concentration ([Ca 2+ ] i ) in pancreatic β cells is central to our understanding of β‐cell physiology and pathology. In this context, there are numerous in vitro studies available but existing in vivo data are scarce. We now critically evaluate the anterior chamber of the eye as an in vivo, non‐invasive, imaging site for measuring [Ca 2+ ] i dynamics longitudinally in three dimensions and at single‐cell resolution. By applying a fluorescently labeled glucose analogue 2‐( N ‐(7‐Nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)Amino)‐2‐Deoxyglucose in vivo, we followed how glucose almost simultaneously distributes to all cells within the islet volume, resulting in [Ca 2+ ] i changes. We found that almost all β cells in healthy mice responded to a glucose challenge, while in hyperinsulinemic, hyperglycemic mice about 80% of the β cells could not be further stimulated from fasting basal conditions. This finding indicates that our imaging modality can resolve functional heterogeneity within the β‐cell population in terms of glucose responsiveness. Importantly, we demonstrate that glucose homeostasis is markedly affected using isoflurane compared to hypnorm/midazolam anesthetics, which has major implications for [Ca 2+ ] i measurements. In summary, this setup offers a powerful tool to further investigate in vivo pancreatic β‐cell [Ca 2+ ] i response patterns at single‐cell resolution in health and disease.