Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Sep 11;18(18):2873-2882.
doi: 10.1039/c8lc00624e.

Microfluidic-enabled quantitative measurements of insulin release dynamics from single islets of Langerhans in response to 5-palmitic acid hydroxy stearic acid

Basel Bandak  1 , Lian Yi, Michael G Roper
Affiliations

Microfluidic-enabled quantitative measurements of insulin release dynamics from single islets of Langerhans in response to 5-palmitic acid hydroxy stearic acid

Basel Bandak et al. Lab Chip. .

Abstract

Proper release of insulin from pancreatic islets of Langerhans is essential for maintaining glucose homeostasis. For full efficacy, both the pattern and the amount of hormone release are critical. It is therefore important to understand how insulin levels are secreted from single islets in both a quantitative fashion and in a manner that resolves temporal dynamics. In this study, we describe a microfluidic analytical system that can both quantitatively monitor insulin secretion from single islets while simultaneously maintaining high temporal sampling to resolve dynamics of release. We have applied this system to determine the acute and chronic effects of a recently-identified lipid, 5-palmitic acid hydroxy stearic acid (5-PAHSA), which is a member of the fatty acid hydroxy fatty acid class of lipids that are upregulated in healthy individuals. Chronic incubation (48 h) with 5-PAHSA significantly increased glucose-stimulated insulin secretion (GSIS) in murine islets compared to chronic incubation without the lipid or in the presence of palmitic acid (PA). The studies were continued in human islets from both healthy donors and donors diagnosed with type 2 diabetes mellitus (T2DM). Total amounts of GSIS were not only augmented in islets that were chronically incubated with 5-PAHSA, but the dynamic insulin release profiles also improved as noted by more pronounced insulin oscillations. With this quantitative microfluidic system, we have corroborated the anti-diabetic effects of 5-PAHSA by demonstrating improved islet function after chronic incubation with this lipid via improved oscillatory dynamics along with higher basal and peak release rates.

PubMed Disclaimer

Figures

Fig. 1.
Fig. 1.. Development and calibration of the quantitative microfluidic system.
(A) 3D rendition of the quantitative islet chamber system where the perfusion solution (blue arrows) captures all of the islet releasate. The released compounds homogenize as they travel through the perfusion mixing channel. As the perfusate leaves the device through the sampling chamber, a small fraction of the solution enters the EOF channel for quantitation by the immunoassay system. The inset shows a picture of a single murine islet situated in the islet chamber with the perfusion mixing channel situated below the islet. (B) A simulation of a periodic insulin signal emanating from an islet at 3 positions within the newly developed design. Positions A, B, and C refer to the 3 spatial positions of the islet within the chamber as depicted by the inset. The measurements show reproducible detection of insulin that are independent of islet position. (C) Calibration curve of the immunoassay system shows the measured B/F plotted against the insulin concentration. The red line is a best-fit curve using a 4-parameter logistic function. The LOD was calculated to be 10 nM and RSD for each standard was < 2%.
Fig. 2.
Fig. 2.. GSIS profiles of murine islets incubated with serum.
Representative GSIS profiles (black lines, left y-axis) from single mouse islets in response to a glucose challenge (blue line, right y-axis). These traces were chosen to show biphasic pulsatile responses with (A) slower and (B) faster periods. (C) The mean response of insulin release stimulated with 11 mM glucose is shown by the black line with the error bars (grey) corresponding to ± 1 SD.
Fig. 3.
Fig. 3.. Acute delivery of 5-PAHSA to mouse islets.
Representative single islet insulin release profiles in response to the acute exposure of (A) 20, 40, and 80 μM 5-PAHSA. The timing of the lipid delivery is denoted by the blue bar on the graph from 20 – 40 min. (B) The percent increase in secretion is plotted as a function of the 5-PAHSA concentration applied.
Fig. 4.
Fig. 4.. Chronic incubations of murine islets with 5-PAHSA or PA.
The average (± 1 SD) GSIS from murine islets after 48-h incubation with (A) 40 μM 5-PAHSA (n = 5 islets) or (B) FA-free BSA (n=7 islets). (C) The amount of insulin released (in pg) during phase 1 and phase 2 incubated with (+) and without (−) 5-PAHSA, or in a lipotoxic condition ((+) PA). * p < 0.05.
Fig. 5.
Fig. 5.. Chronic incubation of healthy human islets.
The average insulin release profiles (black lines, left y-axis) from healthy human islets exposed to 11 mM glucose levels (blue lines, right y-axis) after 48-h incubation of healthy islets in culture media containing (A) 40 μM 5-PAHSA (n = 9 islets) and (B) FA-free HSA (n = 7 islets) are shown. The error bars (grey) correspond to ± 1SD. (C) The amounts of insulin (in pg) for phase 1 and phase 2 from the healthy human islets that have been incubated with (+) and without (−) 5-PAHSA. * p < 0.05.
Fig. 6.
Fig. 6.. Chronic incubation of T2DM human islets.
The average insulin release profiles (black lines, left y-axis) from T2DM human islets exposed to 11 mM glucose levels (blue lines, right y-axis) after 48-h incubation of T2DM islets in culture media containing (A) 40 μM 5-PAHSA (n = 7 islets) and (B) FA-free HSA (n = 5 islets) are shown. The error bars (grey) correspond to ± 1SD. (C) The amounts of insulin (in pg) for phase 1 and phase 2 from the T2DM human islets that have been incubated with (+) and without (−) 5-PAHSA.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Yore MM, Syed I, Moraes-Vieira PM, Zhang T, Herman MA, Homan EA, Patel RT, Lee J, Chen S, Peroni OD, Dhaneshwar AS, Hammarstedt A, Smith U, McGraw TE, Saghatelian A and Kahn BB, Cell, 2014, 159, 318–332. - PMC - PubMed
    1. Boden G, Diabetes, 1997, 46, 3–10. - PubMed
    1. McGarry JD and Dobbins RL, Diabetologia, 1999, 42, 128–138. - PubMed
    1. Syed I, Lee J, Moraes-Vieira PM, Donaldson CJ, Sontheimer A, Aryal P, Wellenstein K, Kolar MJ, Nelson AT, Siegel D, Mokrosinski J, Farooqi IS, Zhao JJ, Yore MM, Peroni OD, Saghatelian A and Kahn BB, Cell Metab, 2018, 27, 419–427.e414. - PMC - PubMed
    1. Brezinova M, Kuda O, Hansikova J, Rombaldova M, Balas L, Bardova K, Durand T, Rossmeisl M, Cerna M, Stranak Z and Kopecky J, Biochim Biophys Acta, 2018, 1863, 126–131. - PubMed

Publication types

-