In Vitro Growth of Neonatal Rat Islet Cells is Stimulated by Adhesion to Matrix

Abstract

We examined DNA synthesis in non-enzymatically isolated neonatal rat pancreatic islets sub-cultured to eliminate fibroblast contamination, which was excluded both by demonstrating no effect of fibroblast growth factor (FGF) on 3H-thymidine incorporation and by immunofluorescence of attached islets using a mouse anti-fibroblast monoclonal antibody. 3H-thymidine incorporation in islets increased with increasing glucose up to a concentration of 21.1 mM in both free-floating islets (11,789 cpm/micrograms DNA +/- 1,610 SEM) and islets attached to fibronectin coated plastic (43,043 cpm/micrograms DNA +/- 9,203 SEM). These values were significantly higher when compared to 3H-thymidine incorporation in medium containing 11.1 mM glucose (p < 0.007, and p < 0.0001 for free-floating and attached islets respectively). 3H-thymidine incorporation was significantly higher in attached islets than in free-floating islets at all glucose concentrations tested (p < 0.005 at 11.1 mM, 16.1 mM, and 21.1 mM; and p < 0.01 at 26.1 mM). 5-bromo-2'-deoxyuridine (BrDU) staining of islets showed an increased number of positive nuclei in cells localised within attached islets (37.6 nuclei per islet +/- 5.1 SEM) compared to free-floating islets (7.62 nuclei per islet +/- 1.04 SEM, p < 0.001), indicating that attachment influenced proliferation of islet cells not physically in contact with the matrix. No difference in glucose-stimulated insulin release was observed between attached and free-floating islets. In conclusion, a fibroblast free islet culture was used to document the stimulatory effect of islet attachment on DNA synthesis, which was greater than the stimulation exerted by glucose alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged Survival of Adult Rat Pancreatic Islets Transfected with E1A-12s Adenovirus

“…In addition, these peripheral islets possessed significant DNA synthesis, as confirmed by BrdU fluorescence. Our data also support several other observations that peripheral islet cells are mitotically active compared with the internal islet cells (54). Of interest is that our transfection methods seemed to target primarily the peripheral islet cells.…”

Ventromedial hypothalamic lesions change the expression of cell proliferation-related genes and morphology-related genes in rat pancreatic islets

“…14,15 The importance of ECM has been shown for the maintenance of insulin secretion in cultured islets and for the proper development of islets. 16,17 As such, further studies that address the role of islet architecture in islet adaptation to insulin resistance are warranted.…”

Is pancreas development abnormal in the non-obese diabetic mouse, a spontaneous model of type I diabetes?

“…As regards the normal rodent pancreas, a few reports have shown in vitro that ECM proteins affect fetal or neonatal endocrine tissue development: laminin induces ß-cell differentiation in mouse fetuses (28), fibronectin stimulates islet proliferation and insulin secretion in newborn rats (29), and collagen affects the islet distribution of ß versus non-ß cells (30). Moreover, the levels of some ECM-degrading metalloproteinases are able to affect in vitro rat islet morphogenesis (17).…”