Therefore, using clinical MRI, the probe quantitatively differentiates, in the same mouse strain, between female animals featuring a 50% loss of beta cells and the males featuring an almost complete loss of beta cells. Conclusions/interpretation The approach addresses several of the hurdles that have so far limited the non-invasive imaging of beta cells, including the potential to repeatedly monitor the very same animals using clinically available equipment, and to differentiate graded deficits of beta cells. Electronic supplementary material The online version of this article (doi:10.1007/s00125-014-3442-2) contains peer-reviewed but unedited supplementary material, which is available to authorised users. locus of the X chromosome. which mimic the changes expected in type 1 and type 2 diabetes, respectively. Results We showed that this probe selectively labelled beta cells in situ, imaged in vivo native pancreatic islets and evaluated their loss after diphtheria toxin administration, inside a model of graded beta cell deletion. Therefore, using medical MRI, the probe quantitatively differentiates, in the same mouse strain, between female animals featuring Forskolin a 50% loss of beta cells and the males featuring an almost Forskolin complete loss of beta cells. Conclusions/interpretation The approach addresses several of the hurdles that have so far limited the non-invasive imaging of beta cells, including the potential to repeatedly monitor the very same animals using clinically available equipment, and to differentiate graded deficits of beta cells. Electronic supplementary material The online version of this article (doi:10.1007/s00125-014-3442-2) contains peer-reviewed but unedited supplementary material, which is available to authorised users. locus of the X Mouse Monoclonal to 14-3-3 chromosome. Therefore, with this model, DT administration prospects to a parallel loss of insulin content material and beta cells, which is definitely partially due to the random X inactivation (normally 50%) in hemizygous female mice and nearly total ablation in male mice. To evaluate the total insulin content of the pancreas, whole glands were cautiously dissected and extracted in acid-ethanol for 24?h, while reported [34, 35]. Pancreas insulin content material was evaluated using a rodent insulin ELISA kit (Mercodia, Uppsala, Sweden) according to the manufacturers instructions. Biodistribution of the exendinCnanoparticle probe Male RIP-DTr mice [33] were injected through the retro-orbital venous plexus with 5?g/(g body weight) of either Np647CExCys1 or Np647CExScra or were co-injected with 5?g Np647CExCys1 and two subcutaneous doses of 750?g free exendin-4 at a 12?h interval (the subcutaneous route was chosen to slow Forskolin down the absorption of the free peptide into the blood circulation). Mice were killed 24?h later on, and immediately perfused via the remaining ventricle, 1st with 10?ml 0.9% NaCl (154?mmol/l) and then with 10?ml 4% paraformaldehyde in 0.1?mol/l phosphate buffer at 37C. The pancreas, liver, spleen, kidneys, lung, duodenum and heart were harvested and fixed in paraformaldehyde for 2?h at 4C. The organs were rinsed for 2?h in phosphate buffer at 4C, and their fluorescence recorded with an IVIS Spectrum (PerkinElmer, Waltham, MA, USA) equipped with filters for Alexa 647. Related organs from mice injected with Np647CExCys1 and Np647CExScra, as well as from mice injected with Np647CExCys1 with and without an excess of exendin-4, were imaged in parallel. To differentiate between cells autofluorescence and Forskolin fluorescence due to the A647 fluorochrome, the organs were excited using 535, 570, 605 and 640?nm excitation filters and fluorescence was recorded using a 680?nm emission filter. Spectral unmixing was performed with the Living Image 4.3.1 software (PerkinElmer, Forskolin Waltham, MA, USA) and fluorescence signs (expressed as average radiant efficiency, 107 [p sC1?cmC2?srC1]/[W/cm2]) were quantified within the unmixed image after suppression of the autofluorescence levels. The fixed pancreas, liver, spleen and kidneys were also rinsed for 15?h in 30% sucrose, embedded in OCT compound (Sakura Finetek, Torrance, CA, USA), and cryo-sectioned at 7?m thickness. Sections were mounted and examined by fluorescence microscopy. Pancreas sections were immunolabelled using either guinea pig antibodies against insulin (Ventrex Laboratories, Portland, ME, USA), diluted 1/200, mouse antibodies against glucagon (Sigma-Aldrich), diluted 1/2,000, or rabbit antibodies against exendin-4 (Abcam, Cambridge,.