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  • 1.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Exploring the pancreas with optical projection tomography2012Ingår i: Imaging in Medicine, ISSN 1755-5191, Vol. 4, nr 1, s. 5-7Artikel i tidskrift (Refereegranskat)
  • 2.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Imaging shows insulin-producing cells in diabetes2013Ingår i: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 44, s. III-IIIArtikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 3.
    Ahlgren, Ulf
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Gotthardt, Martin
    Department of Nuclear Medicine, Nijmegen, Netherlands.
    Approaches for imaging islets2010Ingår i: Advances in Experimental Medicine and Biology, ISSN 0065-2598, E-ISSN 2214-8019, Vol. 654, s. 39-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The establishment of improved technologies for imaging of the pancreas is a key element in addressing several aspects of diabetes pathogenesis. In this respect, the development of a protocol that allows for non-invasive scoring of human islets, or islet beta-cells, is of particular importance. The development of such a technology would have profound impact on both clinical and experimental medicine, ranging from early diagnosis of diabetes to the evaluation of therapeutic regimes. Another important task is the development of modalities for high-resolution imaging of experimental animal models for diabetes. Rodent models for diabetes research have for decades been instrumental to the diabetes research community. The ability to image, and to accurately quantify, key players of diabetogenic processes with molecular specificity will be of great importance for elucidating mechanistic aspects of the disease. This chapter aims to overview current progress within these research areas.

  • 4.
    Ahlgren, Ulf
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Optical imaging of islets: new possibilities by the development of infrared fluorescent proteins2009Ingår i: Islets, ISSN 1938-2022, Vol. 1, nr 2, s. 163-164Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The capacity to record the spatial and quantitative distribution of cellular subtypes involved in diabetogenic processes is a key element in experimental diabetes research. A non-invasive technique to accurately monitor parameters such as pancreatic β-cell mass (BCM) and its distribution would provide a stepping stone in understanding different aspects of diabetes pathogenesis. It would also assist in the development of therapeutic regimes by providing a tool for the evaluation of anti-diabetic drugs or other curative or diagnostic measures. At present, a range of imaging modalities are being explored for this purpose. Whereas nuclear imaging techniques, characterised by their high tissue penetration depth but relatively low spatial resolution, appear most promising for the study of humans and large animals, optical imaging enables a route to cost-effective, high sensitivity, high resolution imaging in rodent models for disease. In this commentary, the potential impact of infrared fluorescent proteins (IFPs), as recently reported by Shu et al in Science, for imaging of the pancreas in small animals will be discussed.

  • 5.
    Ahlgren, Ulf
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Kostromina, Elena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Imaging the pancreatic beta cell: chapter 132011Ingår i: Type 1 diabetes: pathogenesis, genetics and immunotherapy / [ed] David Wagner, InTech, 2011Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This book is a compilation of reviews about the pathogenesis of Type 1 Diabetes. T1D is a classic autoimmune disease. Genetic factors are clearly determinant but cannot explain the rapid, even overwhelming expanse of this disease. Understanding etiology and pathogenesis of this disease is essential. A number of experts in the field have covered a range of topics for consideration that are applicable to researcher and clinician alike. This book provides apt descriptions of cutting edge technologies and applications in the ever going search for treatments and cure for diabetes. Areas including T cell development, innate immune responses, imaging of pancreata, potential viral initiators, etc. are considered.

  • 6.
    Alanentalo, Tomas
    et al.
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Asayesh, Amir
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Morrison, Harris
    Lorén, Christina E
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Holmberg, Dan
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM). Umeå universitet, Medicinsk fakultet, Medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Sharpe, James
    Ahlgren, Ulf
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Tomographic molecular imaging and 3D quantification within adult mouse organs.2007Ingår i: Nature Methods, ISSN 1548-7091, E-ISSN 1548-7105, Vol. 4, nr 1, s. 31-33Artikel i tidskrift (Refereegranskat)
  • 7.
    Alanentalo, Tomas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Mayans, Sofia
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Nilsson, Anna Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Sharpe, James
    Larefalk, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Holmberg, Dan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Quantification and 3-D imaging of the insulitis-induced destruction of β-cells in murine type 1 diabetes2010Ingår i: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 59, nr 7, s. 1756-1764Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: The aim of this study was to refine the information regarding the quantitative and spatial dynamics of infiltrating lymphocytes and remaining beta-cell volume during the progression of type 1 diabetes in the NOD mouse model of the disease.

    Research design and methods: Using an ex vivo technique, optical projection tomography (OPT), we quantified and assessed the 3D spatial development and progression of insulitis and beta-cell destruction in pancreas from diabetes prone NOD and non-diabetes prone congenic NOD.H-2b mice between 3 and 16 weeks of age.

    Results: Together with results showing the spatial dynamics of the insulitis process we provide data of beta-cell volume distributions down to the level of the individual islets and throughout the pancreas during the development and progression of type 1 diabetes. Our data provide evidence for a compensatory growth potential of the larger insulin(+) islets during the later stages of the disease around the time point for development of clinical diabetes. This is in contrast to smaller islets, which appear less resistant to the autoimmune attack. We also provide new information on the spatial dynamics of the insulitis process itself, including its apparently random distribution at onset, the local variations during its further development, and the formation of structures resembling tertiary lymphoid organs at later phases of insulitis progression.

    Conclusions: Our data provides a powerful tool for phenotypic analysis of genetic and environmental effects on type 1 diabetes etiology as well as for evaluating the potential effect of therapeutic regimes.

  • 8.
    Alanentalo, Tomas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Lorén, Christina E
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Larefalk, Asa
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Sharpe, James
    Holmberg, Dan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    High-resolution three-dimensional imaging of islet-infiltrate interactions based on optical projection tomography assessments of the intact adult mouse pancreas2008Ingår i: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 13, nr 5, s. 054070-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A predicament when assessing the mechanisms underlying the pathogenesis of type-1 diabetes (T1D) has been to maintain simultaneous global and regional information on the loss of insulin-cell mass and the progression of insulitis. We present a procedure for high-resolution 3-D analyses of regions of interest (ROIs), defined on the basis of global assessments of the 3-D distribution, size, and shape of molecularly labeled structures within the full volume of the intact mouse pancreas. We apply a refined protocol for optical projection tomography (OPT)-aided whole pancreas imaging in combination with confocal laser scanning microscopy of site-directed pancreatic microbiopsies. As such, the methodology provides a useful tool for detailed cellular and molecular assessments of the autoimmune insulitis in T1D. It is anticipated that the same approach could be applied to other areas of research where 3-D molecular distributions of both global and regional character is required.

  • 9.
    Asayesh, Amir
    et al.
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Alanentalo, Tomas
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Khoo, Nelson K S
    Ahlgren, Ulf
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Developmental expression of metalloproteases ADAM 9, 10, and 17 becomes restricted to divergent pancreatic compartments.2005Ingår i: Developmental Dynamics, ISSN 1058-8388, E-ISSN 1097-0177, Vol. 232, nr 4, s. 1105-1114Artikel i tidskrift (Refereegranskat)
  • 10.
    Asayesh, Amir
    et al.
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Sharpe, James
    Watson, Robert P
    Hecksher-Sørensen, Jacob
    Hastie, Nicholas D
    Hill, Robert E
    Ahlgren, Ulf
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Spleen versus pancreas: strict control of organ interrelationship revealed by analyses of Bapx1-/- mice.2006Ingår i: Genes & Development, ISSN 0890-9369, E-ISSN 1549-5477, Vol. 20, nr 16, s. 2208-2213Artikel i tidskrift (Refereegranskat)
  • 11. Baeyens, Luc
    et al.
    Lemper, Marie
    Leuckx, Gunter
    De Groef, Sofie
    Bonfanti, Paola
    Stange, Geert
    Shemer, Ruth
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Scheel, David W
    Pan, Fong C
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Gu, Guoqiang
    Stoffers, Doris A
    Dor, Yuval
    Ferrer, Jorge
    Gradwohl, Gerard
    Wright, Christopher VE
    Van de Casteele, Mark
    German, Michael S
    Bouwens, Luc
    Heimberg, Harry
    Transient cytokine treatment induces acinar cell reprogramming and regenerates functional beta cell mass in diabetic mice2014Ingår i: Nature Biotechnology, ISSN 1087-0156, E-ISSN 1546-1696, Vol. 32, nr 1, s. 76-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reprogramming of pancreatic exocrine cells into cells resembling beta cells may provide a strategy for treating diabetes. Here we show that transient administration of epidermal growth factor and ciliary neurotrophic factor to adult mice with chronic hyperglycemia efficiently stimulates the conversion of terminally differentiated acinar cells to beta-like cells. Newly generated beta-like cells are epigenetically reprogrammed, functional and glucose responsive, and they reinstate normal glycemic control for up to 248 d. The regenerative process depends on Stat3 signaling and requires a threshold number of Neurogenin 3 (Ngn3)-expressing acinar cells. In contrast to previous work demonstrating in vivo conversion of acinar cells to beta-like cells by viral delivery of exogenous transcription factors, our approach achieves acinar-to-beta-cell reprogramming through transient cytokine exposure rather than genetic modification.

  • 12.
    Cheddad, Abbas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Prunskaite-Hyyryläinen, Renata
    Oulu Center for Cell-Matrix Research, Biocenter Oulu, Laboratory of Developmental Biology and Department of Medical Biochemistry and Molecular Biology, Institute of Biomedicine, University of Oulu, Finland.
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Georgsson, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Vainio, Seppo
    Oulu Center for Cell-Matrix Research, Biocenter Oulu, Laboratory of Developmental Biology and Department of Medical Biochemistry and Molecular Biology, Institute of Biomedicine, University of Oulu, Finland.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Improving signal detection in emission optical projection tomography via single source multi-exposure image fusion2013Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 14, s. 16584-16604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate a technique to improve structural data obtained from Optical Projection Tomography (OPT) using Image Fusion (IF) and contrast normalization. This enables the visualization of molecular expression patterns in biological specimens with highly variable contrast values. In the approach, termed IF-OPT, different exposures are fused by assigning weighted contrasts to each. When applied to projection images from mouse organs and digital phantoms our results demonstrate the capability of IF-OPT to reveal high and low signal intensity details in challenging specimens. We further provide measurements to highlight the benefits of the new algorithm in comparison to other similar methods.

  • 13.
    Cheddad, Abbas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Svensson, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Sharpe, James
    Georgsson, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Image processing assisted algorithms for optical projection tomography2012Ingår i: IEEE Transactions on Medical Imaging, ISSN 0278-0062, E-ISSN 1558-254X, Vol. 31, nr 1, s. 1-15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since it was first presented in 2002, optical projection tomography (OPT) has emerged as a powerful tool for the study of biomedical specimen on the mm to cm scale. In this paper, we present computational tools to further improve OPT image acquisition and tomographic reconstruction. More specifically, these methods provide: semi-automatic and precise positioning of a sample at the axis of rotation and a fast and robust algorithm for determination of postalignment values throughout the specimen as compared to existing methods. These tools are easily integrated for use with current commercial OPT scanners and should also be possible to implement in "home made" or experimental setups for OPT imaging. They generally contribute to increase acquisition speed and quality of OPT data and thereby significantly simplify and improve a number of three-dimensional and quantitative OPT based assessments.

  • 14.
    Eriksson, Anna U.
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Svensson, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Cheddad, Abbas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Kostromina, Elena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Norlin, Nils
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Pileggi, Antonello
    Cell Transplants Center, Diabetes Research Institute, University of Miami.
    Sharpe, James
    EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Catalan Institute of Research and Advance Studies.
    Georgsson, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Alanentalo, Tomas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Near infrared optical projection tomography for assessments of beta-cell mass distribution in diabetes research2013Ingår i: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, Vol. 71, artikel-id e50238Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By adapting OPT to include the capability of imaging in the near infrared (NIR) spectrum, we here illustrate the possibility to image larger bodies of pancreatic tissue, such as the rat pancreas, and to increase the number of channels (cell types) that may be studied in a single specimen. We further describe the implementation of a number of computational tools that provide: 1/ accurate positioning of a specimen's (in our case the pancreas) centre of mass (COM) at the axis of rotation (AR)2; 2/ improved algorithms for post-alignment tuning which prevents geometric distortions during the tomographic reconstruction2 and 3/ a protocol for intensity equalization to increase signal to noise ratios in OPT-based BCM determinations3. In addition, we describe a sample holder that minimizes the risk for unintentional movements of the specimen during image acquisition. Together, these protocols enable assessments of BCM distribution and other features, to be performed throughout the volume of intact pancreata or other organs (e.g. in studies of islet transplantation), with a resolution down to the level of individual islets of Langerhans.

  • 15. Eter, Wael A.
    et al.
    Parween, Saba
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Joosten, Lieke
    Frielink, Cathelijne
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Brom, Maarten
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Gotthardt, Martin
    SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for beta-cell mass assessments2016Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, artikel-id 24576Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in beta-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total beta-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate beta-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of beta-cells. Uptake of a promising radiotracer for beta-cell imaging by SPECT, In-111-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of In-111-exendin-3 and insulin positive beta-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of beta-cell radiotracers.

  • 16. Grong, E.
    et al.
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Arbo, I. B.
    Eriksson, M.
    Kulseng, B. E.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Mårvik, R.
    The effect of hypergastrinemia following sleeve gastrectomy and pantoprazole on type 2 diabetes mellitus and beta-cell mass in Goto-Kakizaki rats2018Ingår i: Journal of Endocrinological Investigation, ISSN 0391-4097, E-ISSN 1720-8386, Vol. 41, nr 6, s. 691-701Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: Metabolic surgery alters the secretion of gastrointestinal hormones that influence glycemic control. Elevated gastrin has been suggested to benefit patients with type 2 diabetes and has been reported following sleeve gastrectomy in rats. The present study compares the effect of hypergastrinemia following sleeve gastrectomy with proton-pump inhibitor therapy on glycemic control and beta-cell mass in lean, diabetic animals.

    Methods: Thirty-three diabetic Goto-Kakizaki rats were randomized into pantoprazole + sham operation (GK-PPI), sleeve gastrectomy (GK-SG) and vehicle + sham operation (GK-V). Body weight, glucose parameters, HbA1c, glucagon-like peptide 1, gastrin, insulin and lipids were evaluated for eighteen postoperative weeks. Total beta-cell mass was quantified by optical projection tomography.

    Results: After surgery, body weight development was equal among groups (Pg = 0.75). Fasting and stimulated gastrin increased for GK-PPI and GK-SG vs. GK-V (p < 0.05 for all). Fasting blood glucose was decreased for GK-PPI and GK-SG vs. GK-V (p < 0.05 and p = 0.052). HbA1c was lower for GK-SG vs. GK-V at 6 weeks and for GK-PPI vs. GK-V at twelve- and eighteen weeks postoperative (p < 0.05 for all); a borderline difference was observed for GK-SG vs. GK-V at 18 weeks (p = 0.054). Total- and LDL cholesterol was elevated for GK-PPI compared to the other two groups (p < 0.05 for all). Beta-cell mass did not differ among groups (p = 0.35).

    Conclusions: Hypergastrinemia following sleeve gastrectomy and pantoprazole has a similar, modest effect on glycemic control in Goto-Kakizaki rats but does not enhance beta-cell mass after 18 weeks. Hypergastrinemia in the setting of T2DM might be of clinical relevance.

  • 17. Grong, Eivind
    et al.
    Kulseng, Bård
    Arbo, Ingerid Brænne
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Mårvik, Ronald
    Sleeve gastrectomy, but not duodenojejunostomy, preserves total beta-cell mass in Goto-Kakizaki rats evaluated by three-dimensional optical projection tomography2016Ingår i: Surgical Endoscopy, ISSN 0930-2794, E-ISSN 1432-2218, Vol. 30, nr 2, s. 532-542Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background In type 2 diabetes mellitus, there is a progressive loss of beta-cell mass. Bariatric surgery has in recent investigations showed promising results in terms of diabetes remission, but little is established regarding the effect of surgery on the survival or regeneration of pancreatic beta-cells. In this study, we aim to explore how bariatric surgery with its subsequent hormonal alterations affects the islets of Langerhans.

    Methods Twenty-four Goto-Kakizaki rats were operated with duodenojejunostomy (DJ), sleeve gastrectomy (SG) or sham operation. From the 38th week after surgery, body weight, fasting blood glucose, glycosylated hemoglobin, mixed meal tolerance with repeated measures of insulin, glucagon-like peptide 1, gastrin and total ghrelin were evaluated. Forty-six weeks after surgery, the animals were euthanized and the total beta-cell mass in all animals was examined by three-dimensional volume quantification by optical projection tomography based on the signal from insulin-specific antibody staining.

    Results Body weight did not differ between groups (Pg = 0.37). SG showed lower fasting blood glucose compared to DJ and sham (Pg = 0.037); HbA1c levels in SG were lower compared to DJ only (p\0.05). GLP-1 levels were elevated for DJ compared to SG and sham (Pg = 0.001), whereas gastrin levels were higher in SG compared to the two other groups (Pg = 0.002). Beta-cell mass was significantly greater in animals operated with SG compared to both DJ and sham (p = 0.036).

    Conclusion Sleeve gastrectomy is superior to duodenojejunostomy and sham operation when comparing the preservation of beta-cell mass 46 weeks after surgery in Goto-Kakizaki rats. This could be related to both the increased gastrin levels and the long-term improvement in glycemic parameters observed after this procedure.

  • 18. Hecksher-Sørensen, Jacob
    et al.
    Watson, Robert P
    Lettice, Laura A
    Serup, Palle
    Eley, Lorraine
    De Angelis, Carlo
    Ahlgren, Ulf
    Umeå universitet, Medicinsk fakultet, Umeå centrum för molekylär medicin (UCMM).
    Hill, Robert E
    The splanchnic mesodermal plate directs spleen and pancreatic laterality, and is regulated by Bapx1/Nkx3.2.2004Ingår i: Development, ISSN 0950-1991, Vol. 131, nr 19, s. 4665-75Artikel i tidskrift (Refereegranskat)
  • 19.
    Holmberg, Dan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Imaging the pancreas: from ex vivo to non-invasive technology.2008Ingår i: Diabetologia, ISSN 0012-186X, Vol. 51, nr 12, s. 2148-2154Artikel i tidskrift (Övrigt vetenskapligt)
  • 20.
    Hörnblad, Andreas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Cheddad, Abbas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    An improved protocol for optical projection tomography imaging reveals lobular heterogeneities in pancreatic islet and β-cell mass distribution2011Ingår i: Islets, ISSN 1938-2014, Vol. 3, nr 4, s. 204-208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optical projection tomography (OPT) imaging is a powerful tool for three-dimensional imaging of gene and protein distribution patterns in biomedical specimens. We have previously demonstrated the possibility, by this technique, to extract information of the spatial and quantitative distribution of the islets of Langerhans in the intact mouse pancreas. In order to further increase the sensitivity of OPT imaging for this type of assessment, we have developed a protocol implementing a computational statistical approach: contrast limited adaptive histogram equalization (CLAHE). We demonstrate that this protocol significantly increases the sensitivity of OPT imaging for islet detection, helps preserve islet morphology and diminish subjectivity in thresholding for tomographic reconstruction. When applied to studies of the pancreas from healthy C57BL/6 mice, our data reveal that, at least in this strain, the pancreas harbors substantially more islets than has previously been reported. Further, we provide evidence that the gastric, duodenal and splenic lobes of the pancreas display dramatic differences in total and relative islet and β-cell mass distribution. This includes a 75% higher islet density in the gastric lobe as compared to the splenic lobe and a higher relative volume of insulin producing cells in the duodenal lobe as compared to the other lobes. Altogether, our data show that CLAHE substantially improves OPT based assessments of the islets of Langerhans and that lobular origin must be taken into careful consideration in quantitative and spatial assessments of the pancreas.

  • 21.
    Hörnblad, Andreas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Anna
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Sock, Elisabeth
    Hill, Robert
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Impaired spleen formation perturbs morphogenesis of the gastric lobe of the pancreas2011Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, nr 6, s. e21753-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the extensive use of the mouse as a model for studies of pancreas development and disease, the development of the gastric pancreatic lobe has been largely overlooked. In this study we use optical projection tomography to provide a detailed three-dimensional and quantitative description of pancreatic growth dynamics in the mouse. Hereby, we describe the epithelial and mesenchymal events leading to the formation of the gastric lobe of the pancreas. We show that this structure forms by perpendicular growth from the dorsal pancreatic epithelium into a distinct lateral domain of the dorsal pancreatic mesenchyme. Our data support a role for spleen organogenesis in the establishment of this mesenchymal domain and in mice displaying perturbed spleen development, including Dh +/-, Bapx1-/- and Sox11-/-, gastric lobe development is disturbed. We further show that the expression profile of markers for multipotent progenitors is delayed in the gastric lobe as compared to the splenic and duodenal pancreatic lobes. Altogether, this study provides new information regarding the developmental dynamics underlying the formation of the gastric lobe of the pancreas and recognizes lobular heterogeneities regarding the time course of pancreatic cellular differentiation. Collectively, these data are likely to constitute important elements in future interpretations of the developing and/or diseased pancreas.

  • 22.
    Hörnblad, Andreas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Parween, Saba
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahnfelt-Rønne, J
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    The pancreas2015Ingår i: Kaufman's atlas of mouse development supplement: with coronal sections / [ed] Richard Baldock, Jonathan Bard, Duncan R. Davidson and Gillian Morriss-Kay, Elsevier, 2015, 1, s. 85-94Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This chapter aims to provide a three-dimensional description of the key morphological events, through which a discrete region of the early gut epithelium, as well as its associated mesenchyme, gives rise to the adult pancreas. Facilitated by recent advances in optical imaging techniques, including light sheet fluorescence microscopy and optical projection tomography, we present image series illustrating the growth of the organ and the formation of key morphological and anatomical features. Given the close developmental relationship between the pancreas-associated mesenchyme and the spleen anlage, and thus the potential for the developing spleen to influence pancreas morphogenesis, we include a brief section which covers the early development of this organ. Finally, we describe the spatial and quantitative distribution of the pancreatic endocrine (β-cell) component in adult mice and highlight lobular heterogeneities that may affect phenotypical evaluations of the gland.

  • 23. Ilegems, E.
    et al.
    van Krieken, P. P.
    Edlund, P. K.
    Dicker, A.
    Alanentalo, T.
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Mandic, S.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Berggren, P. -O
    Light scattering as an intrinsic indicator for pancreatic islet cell mass and secretion2015Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, artikel-id 10740Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulation and thereby to the development of diabetes. It is therefore necessary to develop tools for the assessment of both pancreatic islet mass and function, with the aim of understanding cellular regulatory mechanisms and factors guiding islet plasticity. Although most of the existing techniques rely on the use of artificial indicators, we present an imaging methodology based on intrinsic optical properties originating from mature insulin secretory granules within endocrine cells that reveals both pancreatic islet mass and function. We demonstrate the advantage of using this imaging strategy by monitoring in vivo scattering signal from pancreatic islets engrafted into the anterior chamber of the mouse eye, and how this versatile and noninvasive methodology permits the characterization of islet morphology and plasticity as well as hormone secretory status.

  • 24. Jo, Junghyo
    et al.
    Hara, Manami
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Sorenson, Robert L.
    Periwal, Vipul
    Mathematical models of pancreatic islet size distributions2012Ingår i: Islets, ISSN 1938-2014, Vol. 4, nr 1, s. 10-19Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The islets of Langerhans, ranging in size from clusters of a few cells to several thousand cells, are scattered near large blood vessels. While the beta-cell mass in mammals is proportional to body weight, the size ranges of islets are similar between species with different body sizes, possibly reflecting an optimal functional size. The large range of islet sizes suggests a stochastic developmental process. It is not fully understood how islets develop to reach such size distributions, and how their sizes change under certain physiological and pathological conditions such as development, pregnancy, aging, obesity, and diabetes. The lack of a high-resolution in vivo imaging technique for pancreatic islets implies that the only data available to elucidate the dynamics of islet development are cross-sectional quantifications of islet size distributions. In this review, we infer biological processes affecting islet morphology in the large by examining changes of islet size distributions. Neonatal islet formation and growth is shown as a particular example of developing a mathematical model of islet size distribution. Application of this modeling to elucidate islet changes under other conditions is also discussed.

  • 25. Jo, Junghyo
    et al.
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Kilimnik, German
    Department of Medicine, The University of Chicago, Chicago, IL, USA.
    Hara, Manami
    Department of Medicine, The University of Chicago, Chicago, IL, USA.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Periwal, Vipul
    Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
    The fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model2013Ingår i: Physical Biology, ISSN 1478-3967, E-ISSN 1478-3975, Vol. 10, nr 3, s. 036009-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, has not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension of 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with a fractal dimension of 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas.

  • 26.
    Jones, Iwan
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Hägglund, Anna-Carin
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Törnqvist, Gunilla
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Carlsson, Leif
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development2015Ingår i: Disease Models and Mechanisms, ISSN 1754-8403, E-ISSN 1754-8411, Vol. 8, nr 12, s. 1517-1529Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder.

  • 27.
    Lorén, Christina E
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Schrader, John W
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Gunhaga, Lena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    FGF signals induce Caprin2 expression in the vertebrate lens.2009Ingår i: Differentiation, ISSN 0301-4681, E-ISSN 1432-0436, Vol. 77, nr 4, s. 386-394Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lens of the eye is derived from the non-neural ectoderm situated next to the optic vesicle. Fibroblast growth factor (FGF) signals play a major role at various stages of vertebrate lens development ranging from induction and proliferation to differentiation. Less is however known about the identity of genes that are induced by FGF activity within the lens. We have isolated and characterized mouse cytoplasmic activation/proliferation-associated protein-2 (Caprin2), with domains belonging to both the Caprin family and the C1q and tumour necrosis factor (TNF) super-family. Here we show that Caprin2 is expressed in the developing vertebrate lens in mouse and chick, and that Caprin2 expression is up-regulated in primary lens fiber cells, after the induction of crystallins the earliest known markers for differentiated lens fiber cells. Caprin2 is subsequently down-regulated in the centre of the lens at the time and at the position of the first fiber cell denucleation and terminal differentiation. In vitro analyses of lens fiber cell differentiation provide evidence that FGF activity emanating from neighboring prospective retinal cells is required and that FGF8 activity is sufficient to induce Caprin2 in lens fiber cells. These results not only provide evidence that FGF signals induce the newly characterized protein Caprin2 in the lens, but also support the general idea that FGF signals are required for lens fiber cell differentiation.

  • 28. Medina, Anya
    et al.
    Parween, Saba
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ullsten, Sara
    Vishnu, Neelanjan
    Siu, Yuk Ting
    Quach, My
    Bennet, Hedvig
    Balhuizen, Alexander
    Åkesson, Lina
    Wierup, Nils
    Carlsson, Per Ola
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Lernmark, Åke
    Fex, Malin
    Early deficits in insulin secretion, beta cell mass and islet blood perfusion precede onset of autoimmune type 1 diabetes in BioBreeding rats2018Ingår i: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 61, nr 4, s. 896-905Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aims/hypothesis: Genetic studies show coupling of genes affecting beta cell function to type 1 diabetes, but hitherto no studies on whether beta cell dysfunction could precede insulitis and clinical onset of type 1 diabetes are available.

    Methods: We used 40-day-old BioBreeding (BB) DRLyp/Lyp rats (a model of spontaneous autoimmune type 1 diabetes) and diabetes-resistant DRLyp/+ and DR+/+ littermates (controls) to investigate beta cell function in vivo, and insulin and glucagon secretion in vitro. Beta cell mass was assessed by optical projection tomography (OPT) and morphometry. Additionally, measurements of intra-islet blood flow were performed using microsphere injections. We also assessed immune cell infiltration, cytokine expression in islets (by immunohistochemistry and qPCR), as well as islet Glut2 expression and ATP/ADP ratio to determine effects on glucose uptake and metabolism in beta cells.

    Results: DRLyp/Lyp rats were normoglycaemic and without traces of immune cell infiltrates. However, IVGTTs revealed a significant decrease in the acute insulin response to glucose compared with control rats (1685.3 +/- 121.3 vs 633.3 +/- 148.7; p < 0.0001). In agreement, insulin secretion was severely perturbed in isolated islets, and both first- and second-phase insulin release were lowered compared with control rats, while glucagon secretion was similar in both groups. Interestingly, after 5-7 days of culture of islets from DRLyp/Lyp rats in normal media, glucose-stimulated insulin secretion (GSIS) was improved; although, a significant decrease in GSIS was still evident compared with islets from control rats at this time (7393.9 +/- 1593.7 vs 4416.8 +/- 1230.5 pg islet-1 h-1; p < 0.0001). Compared with controls, OPT of whole pancreas from DRLyp/Lyp rats revealed significant reductions in medium (4.1 x 109 +/- 9.5 x 107 vs 3.8 x 109 +/- 5.8 x 107 μm3; p = 0.044) and small sized islets (1.6 x 109 +/- 5.1 x 107 vs 1.4 x 109 +/- 4.5 x 107 μm3; p = 0.035). Finally, we found lower intra-islet blood perfusion in vivo (113.1 +/- 16.8 vs 76.9 +/- 11.8 μl min-1 [g pancreas]-1; p = 0.023) and alterations in the beta cell ATP/ADP ratio in DRLyp/Lyp rats vs control rats.

    Conclusions/interpretation: The present study identifies a deterioration of beta cell function and mass, and intra-islet blood flow that precedes insulitis and diabetes development in animals prone to autoimmune type 1 diabetes. These underlying changes in islet function may be previously unrecognised factors of importance in type 1 diabetes development.

  • 29.
    Nord, Christoffer
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Dicker, Andrea
    Eriksson, Anna
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Grong, Eivind
    Ilegems, Erwin
    Marvik, Ronald
    Kulseng, Bard
    Berggren, Per-Olof
    Gorzsas, Andras
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Biochemical profiling of diabetes disease progression by multivariate vibrational microspectroscopy of the pancreas2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 6646Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the dramatic increase in the prevalence of diabetes, techniques for in situ studies of the underlying pancreatic biochemistry are lacking. Such methods would facilitate obtaining mechanistic understanding of diabetes pathophysiology and aid in prognostic and/or diagnostic assessments. In this report we demonstrate how a multivariate imaging approach (orthogonal projections to latent structures - discriminant analysis) can be applied to generate full vibrational microspectroscopic profiles of pancreatic tissues. These profiles enable extraction of known and previously unrecorded biochemical alterations in models of diabetes, and allow for classification of the investigated tissue with regards to tissue type, strain and stage of disease progression. Most significantly, the approach provided evidence for dramatic alterations of the pancreatic biochemistry at the initial onset of immune-infiltration in the Non Obese Diabetic model for type 1 diabetes. Further, it enabled detection of a previously undocumented accumulation of collagen fibrils in the leptin deficient ob/ob mouse islets. By generating high quality spectral profiles through the tissue capsule of hydrated human pancreata and by in vivo Raman imaging of pancreatic islets transplanted to the anterior chamber of the eye, we provide critical feasibility studies for the translation of this technique to diagnostic assessments of pancreatic biochemistry in vivo.

  • 30.
    Nord, Hanna
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Burguiere, Anne-Cecile
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Muck, Joscha
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    von Hofsten, Jonas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Differential regulation of myosin heavy chains defines new muscle domains in zebrafish2014Ingår i: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 25, nr 8, s. 1384-1395Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Numerous muscle lineages are formed during myogenesis within both slow-and fast-specific cell groups. In this study, we show that six fast muscle-specific myosin heavy chain genes have unique expression patterns in the zebrafish embryo. The expression of tail-specific myosin heavy chain (fmyhc2.1) requires wnt signaling and is essential for fast muscle organization within the tail. Retinoic acid treatment results in reduced wnt signaling, which leads to loss of the fmyhc2.1 domain. Retinoic acid treatment also results in a shift of muscle identity within two trunk domains defined by expression of fmyhc1.2 and fmyhc1.3 in favor of the anteriormost myosin isoform, fmyhc1.2. In summary, we identify new muscle domains along the anteroposterior axis in the zebrafish that are defined by individual nonoverlapping, differentially regulated expression of myosin heavy chain isoforms.

  • 31.
    Norlin, Stefan
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Edlund, Helena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nuclear factor-{kappa}B activity in {beta}-cells is required for glucose-stimulated insulin secretion.2005Ingår i: Diabetes, ISSN 0012-1797, Vol. 54, nr 1, s. 125-32Artikel i tidskrift (Refereegranskat)
  • 32. Pardo, F N
    et al.
    Altirriba, J
    Pradas-Juni, M
    García, A
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Barberà, A
    Slebe, J C
    Yáñez, A J
    Gomis, R
    Gasa, R
    The role of Raf-1 kinase inhibitor protein in the regulation of pancreatic beta cell proliferation in mice.2012Ingår i: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 55, nr 12, s. 3331-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AIMS/HYPOTHESIS: Manoeuvres aimed at increasing beta cell mass have been proposed as regenerative medicine strategies for diabetes treatment. Raf-1 kinase inhibitor protein 1 (RKIP1) is a common regulatory node of the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways and therefore may be involved in regulation of beta cell homeostasis. The aim of this study was to investigate the involvement of RKIP1 in the control of beta cell mass and function.

    METHODS: Rkip1 (also known as Pebp1) knockout (Rkip1 (-/-)) mice were characterised in terms of pancreatic and glucose homeostasis, including morphological and functional analysis. Glucose tolerance and insulin sensitivity were examined, followed by assessment of glucose-induced insulin secretion in isolated islets and beta cell mass quantification through morphometry. Further characterisation included determination of endocrine and exocrine proliferation, apoptosis, MAPK activation and whole genome gene expression assays. Capacity to reverse a diabetic phenotype was assessed in adult Rkip1 (-/-) mice after streptozotocin treatment.

    RESULTS: Rkip1 (-/-) mice exhibit a moderately larger pancreas and increased beta cell mass and pancreatic insulin content, which correlate with an overall improvement in whole body glucose tolerance. This phenotype is established in young postnatal stages and involves enhanced cellular proliferation without significant alterations in cell death. Importantly, adult Rkip1 (-/-) mice exhibit rapid reversal of streptozotocin-induced diabetes compared with control mice.

    CONCLUSIONS/INTERPRETATION: These data implicate RKIP1 in the regulation of pancreatic growth and beta cell expansion, thus revealing RKIP1 as a potential pharmacological target to promote beta cell regeneration.

  • 33.
    Parween, Saba
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Kostromina, Elena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Spatial and quantitative datasets of the pancreatic beta-cell mass distribution in lean and obese mice2017Ingår i: Scientific Data, E-ISSN 2052-4463, Vol. 4, artikel-id 170031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A detailed understanding of pancreatic β-cell mass distribution is a key element to fully appreciate the pathophysiology of models of diabetes and metabolic stress. Commonly, such assessments have been performed by stereological approaches that rely on the extrapolation of two-dimensional data and provide very limited topological information. We present ex vivo optical tomographic data sets of the full β-cell mass distribution in cohorts of obese ob/ob mice and their lean controls, together with information about individual islet β-cell volumes, their three-dimensional coordinates and shape throughout the volume of the pancreas between 4 and 52 weeks of age. These data sets offer the currently most comprehensive public record of the β-cell mass distribution in the mouse. As such, they may serve as a quantitative and topological reference for the planning of a variety of in vivo or ex vivo experiments including computational modelling and statistical analyses. By shedding light on intra- and inter-lobular variations in β-cell mass distribution, they further provide a powerful tool for the planning of stereological sampling assessments.

  • 34.
    Parween, Saba
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Kostromina, Elena
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Lindström, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Intra-islet lesions and lobular variations in β-cell mass expansion in ob/ob mice revealed by 3D imaging of intact pancreas2016Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, artikel-id 34885Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The leptin deficient ob/ob mouse is a widely used model for studies on initial aspects of metabolic disturbances leading to type 2 diabetes, including insulin resistance and obesity. Although it is generally accepted that ob/ob mice display a dramatic increase in β-cell mass to compensate for increased insulin demand, the spatial and quantitative dynamics of β-cell mass distribution in this model has not been assessed by modern optical 3D imaging techniques. We applied optical projection tomography and ultramicroscopy imaging to extract information about individual islet β-cell volumes throughout the volume of ob/ob pancreas between 4 and 52 weeks of age. Our data show that cystic lesions constitute a significant volume of the hyperplastic ob/ob islets. We propose that these lesions are formed by a mechanism involving extravasation of red blood cells/plasma due to increased islet vessel blood flow and vessel instability. Further, our data indicate that the primary lobular compartments of the ob/ob pancreas have different potentials for expanding their β-cell population. Unawareness of the characteristics of β-cell expansion in ob/ob mice presented in this report may significantly influence ex vivo and in vivo assessments of this model in studies of β-cell adaptation and function.

  • 35. Sand, Fredrik Wolfhagen
    et al.
    Hörnblad, Andreas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Johansson, Jenny K
    Lorén, Christina
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Edsbagge, Josefina
    Ståhlberg, Anders
    Magenheim, Judith
    Ilovich, Ohad
    Mishani, Eyal
    Dor, Yuval
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Semb, Henrik
    Growth-limiting role of endothelial cells in endoderm development2011Ingår i: Developmental Biology, ISSN 0012-1606, E-ISSN 1095-564X, Vol. 352, nr 2, s. 267-277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Endoderm development is dependent on inductive signals from different structures in close vicinity, including the notochord, lateral plate mesoderm and endothelial cells. Recently, we demonstrated that a functional vascular system is necessary for proper pancreas development, and that sphingosine-1-phosphate (S1P) exhibits the traits of a blood vessel-derived molecule involved in early pancreas morphogenesis. To examine whether S1P(1)-signaling plays a more general role in endoderm development, S1P(1)-deficient mice were analyzed. S1P(1) ablation results in compromised growth of several foregut-derived organs, including the stomach, dorsal and ventral pancreas and liver. Within the developing pancreas the reduction in organ size was due to deficient proliferation of Pdx1(+) pancreatic progenitors, whereas endocrine cell differentiation was unaffected. Ablation of endothelial cells in vitro did not mimic the S1P(1) phenotype, instead, increased organ size and hyperbranching were observed. Consistent with a negative role for endothelial cells in endoderm organ expansion, excessive vasculature was discovered in S1P(1)-deficient embryos. Altogether, our results show that endothelial cell hyperplasia negatively influences organ development in several foregut-derived organs.

  • 36. Van de Casteele, M.
    et al.
    Leuckx, G.
    Baeyens, L.
    Cai, Y.
    Yuchi, Y.
    Coppens, V.
    De Groef, S.
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Svensson, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahnfelt-Ronne, J.
    Madsen, O. D.
    Waisman, A.
    Dor, Y.
    Jensen, J. N.
    Heimberg, H.
    Neurogenin 3(+) cells contribute to beta-cell neogenesis and proliferation in injured adult mouse pancreas2013Ingår i: Cell Death and Disease, ISSN 2041-4889, E-ISSN 2041-4889, Vol. 4, s. e523-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We previously showed that injury by partial duct ligation (PDL) in adult mouse pancreas activates Neurogenin 3 (Ngn3)(+) progenitor cells that can differentiate to beta cells ex vivo. Here we evaluate the role of Ngn3(+) cells in beta cell expansion in situ. PDL not only induced doubling of the beta cell volume but also increased the total number of islets. beta cells proliferated without extended delay (the so-called 'refractory' period), their proliferation potential was highest in small islets, and 86% of the beta cell expansion was attributable to proliferation of pre-existing beta cells. At sufficiently high Ngn3 expression level, upto 14% of all beta cells and 40% of small islet beta cells derived from non-beta cells. Moreover, beta cell proliferation was blunted by a selective ablation of Ngn3(+) cells but not by conditional knockout of Ngn3 in pre-existing beta cells supporting a key role for Ngn3(+) insulin(-) cells in beta cell proliferation and expansion. We conclude that Ngn3(+) cell-dependent proliferation of pre-existing and newly-formed beta cells as well as reprogramming of non-beta cells contribute to in vivo beta cell expansion in the injured pancreas of adult mice.

  • 37. van Krieken, Pim P.
    et al.
    Dicker, Andrea
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Herrera, Pedro L.
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Berggren, Per-Olof
    Ilegems, Erwin
    Kinetics of functional beta cell mass decay in a diphtheria toxin receptor mouse model of diabetes2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 12440Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Functional beta cell mass is an essential biomarker for the diagnosis and staging of diabetes. It has however proven technically challenging to study this parameter during diabetes progression. Here we have detailed the kinetics of the rapid decline in functional beta cell mass in the RIP-DTR mouse, a model of hyperglycemia resulting from diphtheria toxin induced beta cell ablation. A novel combination of imaging modalities was employed to study the pattern of beta cell destruction. Optical projection tomography of the pancreas and longitudinal in vivo confocal microscopy of islets transplanted into the anterior chamber of the eye allowed to investigate kinetics and tomographic location of beta cell mass decay in individual islets as well as at the entire islet population level. The correlation between beta cell mass and function was determined by complementary in vivo and ex vivo characterizations, demonstrating that beta cell function and glucose tolerance were impaired within the first two days following treatment when more than 50% of beta cell mass was remaining. Our results illustrate the importance of acquiring quantitative functional and morphological parameters to assess the functional status of the endocrine pancreas.

  • 38.
    Witek, Barbara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    El Wakil, Abeer
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Nord, Christoffer
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Ahlgren, Ulf
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Eriksson, Maria
    Umeå universitet, Medicinska fakulteten, Umeå centrum för molekylär medicin (UCMM).
    Vernersson-Lindahl, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Helland, Aslaug
    Alexeyev, Oleg A.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Hallberg, Bengt
    Palmer, Ruth H.
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten). Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg.
    Targeted Disruption of ALK Reveals a Potential Role in Hypogonadotropic Hypogonadism2015Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, nr 5, artikel-id e0123542Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mice lacking ALK activity have previously been reported to exhibit subtle behavioral phenotypes. In this study of ALK of loss of function mice we present data supporting a role for ALK in hypogonadotropic hypogonadism in male mice. We observed lower level of serum testosterone at P40 in ALK knock-out males, accompanied by mild disorganization of seminiferous tubules exhibiting decreased numbers of GATA4 expressing cells. These observations highlight a role for ALK in testis function and are further supported by experiments in which chemical inhibition of ALK activity with the ALK TKI crizotinib was employed. Oral administration of crizotinib resulted in a decrease of serum testosterone levels in adult wild type male mice, which reverted to normal levels after cessation of treatment. Analysis of GnRH expression in neurons of the hypothalamus revealed a significant decrease in the number of GnRH positive neurons in ALK knock-out mice at P40 when compared with control littermates. Thus, ALK appears to be involved in hypogonadotropic hypogonadism by regulating the timing of pubertal onset and testis function at the upper levels of the hypothalamic-pituitary gonadal axis.

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