1. Integrating live cell calcium imaging and tissue damage assessment in a novel model of acute pancreatitisPolona Kovačič, Maša Skelin, Eva Paradiž, Viktória Venglovecz, Loránd Kiss, Gabriella Mihalekné Fűr, Andraž Stožer, Jurij Dolenšek, 2025, published scientific conference contribution abstract Keywords: acute pancreatitis, calcium imaging, LiveDead assay, pancreatic tissue slices, histological analysis
Published in DKUM: 31.03.2025; Views: 0; Downloads: 16
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2. Dual mode of action of acetylcholine on cytosolic calcium oscillations in pancreatic beta and acinar cells in situNastja Sluga, Sandra Postić, Srdjan Sarikas, Ya-Chi Huang, Andraž Stožer, Marjan Rupnik, 2021, original scientific article Abstract: Cholinergic innervation in the pancreas controls both the release of digestive enzymes to support the intestinal digestion and absorption, as well as insulin release to promote nutrient use in the cells of the body. The effects of muscarinic receptor stimulation are described in detail for endocrine beta cells and exocrine acinar cells separately. Here we describe morphological and functional criteria to separate these two cell types in situ in tissue slices and simultaneously measure their response to ACh stimulation on cytosolic Ca2+ oscillations [Ca2+]c in stimulatory glucose conditions. Our results show that both cell types respond to glucose directly in the concentration range compatible with the glucose transporters they express. The physiological ACh concentration increases the frequency of glucose stimulated [Ca2+]c oscillations in both cell types and synchronizes [Ca2+]c oscillations in acinar cells. The supraphysiological ACh concentration further increases the oscillation frequency on the level of individual beta cells, inhibits the synchronization between these cells, and abolishes oscillatory activity in acinar cells. We discuss possible mechanisms leading to the observed phenomena.
Keywords: pancreas tissue slices, acetylcholine, beta cell, acinar cell, Ca2+ oscillations
Published in DKUM: 14.10.2024; Views: 0; Downloads: 18
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3. In vitro disease models of the endocrine pancreasMarko Milojević, Jan Rožanc, Jernej Vajda, Laura Činč Ćurić, Eva Paradiž, Andraž Stožer, Uroš Maver, Boštjan Vihar, 2021, review article Abstract: The ethical constraints and shortcomings of animal models, combined with the demand to study disease pathogenesis under controlled conditions, are giving rise to a new field at the interface of tissue engineering and pathophysiology, which focuses on the development of in vitro models of disease. In vitro models are defined as synthetic experimental systems that contain living human cells and mimic tissue- and organ-level physiology in vitro by taking advantage of recent advances in tissue engineering and microfabrication. This review provides an overview of in vitro models and focuses specifically on in vitro disease models of the endocrine pancreas and diabetes. First, we briefly review the anatomy, physiology, and pathophysiology of the human pancreas, with an emphasis on islets of Langerhans and beta cell dysfunction. We then discuss different types of in vitro models and fundamental elements that should be considered when developing an in vitro disease model. Finally, we review the current state and breakthroughs in the field of pancreatic in vitro models and conclude with some challenges that need to be addressed in the future development of in vitro models.
Keywords: in vitro disease models, pancreas, islet of Langerhans, 3D cell culture, scaffolds, acute tissue slices
Published in DKUM: 01.10.2024; Views: 0; Downloads: 426
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4. The effect of forskolin and the role of Epac2A during activation, activity, and deactivation of beta cell networksMaša Skelin, Jurij Dolenšek, Lidija Križančić Bombek, Viljem Pohorec, Marko Gosak, Marjan Rupnik, Andraž Stožer, 2023, original scientific article Abstract: Beta cells couple stimulation by glucose with insulin secretion and impairments in this coupling play a central role in diabetes mellitus. Cyclic adenosine monophosphate (cAMP) amplifies stimulus-secretion coupling via protein kinase A and guanine nucleotide exchange protein 2 (Epac2A). With the present research, we aimed to clarify the influence of cAMP-elevating diterpene forskolin on cytoplasmic calcium dynamics and intercellular network activity, which are two of the crucial elements of normal beta cell stimulus-secretion coupling, and the role of Epac2A under normal and stimulated conditions. To this end, we performed functional multicellular calcium imaging of beta cells in mouse pancreas tissue slices after stimulation with glucose and forskolin in wild-type and Epac2A knock-out mice. Forskolin evoked calcium signals in otherwise substimulatory glucose and beta cells from Epac2A knock-out mice displayed a faster activation. During the plateau phase, beta cells from Epac2A knock-out mice displayed a slightly higher active time in response to glucose compared with wild-type littermates, and stimulation with forskolin increased the active time via an increase in oscillation frequency and a decrease in oscillation duration in both Epac2A knock-out and wild-type mice. Functional network properties during stimulation with glucose did not differ in Epac2A knock-out mice, but the presence of Epac2A was crucial for the protective effect of stimulation with forskolin in preventing a decline in beta cell functional connectivity with time. Finally, stimulation with forskolin prolonged beta cell activity during deactivation, especially in Epac2A knock-out mice.
Keywords: pancreas, tissue slices, beta cells, calcium imaging, amplifying pathway, forskolin, Epac2A KO, intercellular network
Published in DKUM: 27.05.2024; Views: 193; Downloads: 16
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