Use Of Animal Models To Assess Islet Graft Function Leif Jansson - - PowerPoint PPT Presentation

▶
use of animal models to assess islet graft function
SMART_READER_LITE
LIVE PREVIEW

Use Of Animal Models To Assess Islet Graft Function Leif Jansson - - PowerPoint PPT Presentation

Jun 02, 2023 471 likes •882 views

Use Of Animal Models To Assess Islet Graft Function Leif Jansson Department of Medical Cell Biology Uppsala University Uppsala, Sweden Experimental Transplantation Samples of the isolated human islets can be implanted into normoglycemic

slide-1
SLIDE 1

Use Of Animal Models To Assess Islet Graft Function

Leif Jansson Department of Medical Cell Biology Uppsala University Uppsala, Sweden

slide-2
SLIDE 2

Experimental Transplantation

  • Samples of the isolated human islets can

be implanted into normoglycemic and/or hyperglycemic animals (nude mice or rats)

  • freshly isolated
  • after culture
slide-3
SLIDE 3

Experimental Transplantation

  • Allows for evaluation, at different times

after implantation

  • short term (<3-4 days)
  • long term
slide-4
SLIDE 4

Animals VS Humans

  • Relevance of diabetes models
  • Absence of autoimmunity
  • Number of islets needed for cure
  • Implantation organs
  • Glucotoxicity
  • Lipotoxicity
slide-5
SLIDE 5

Implantation Site

  • Renal capsule
  • Liver (intraportally)
  • Spleen
  • Omental pouch
  • Other
slide-6
SLIDE 6

Experimental Transplantation

SHORT TERM

  • Ability to induce

normoglycemia

  • β-cells
  • Other cells
  • Hormone release

LONG TERM

  • Cellular composition
  • f graft
  • Revascularization
  • Reinnervation
  • Amyloid deposits
slide-7
SLIDE 7

Experimental Transplantation

LONG TERM

  • Cellular composition
  • f graft
  • Revascularization;
  • Reinnervation
  • Amyloid deposits

SHORT TERM

  • Ability to induce

normoglycemia

  • β-cells
  • Other cells
  • Hormone release
slide-8
SLIDE 8

Ability To Induce Normoglycemia

  • Number of islets needed?
  • When after implantation does normo-

glycemia occur?

  • Dependent on implantation organ?
slide-9
SLIDE 9

Experimental Transplantation

LONG TERM

  • Cellular composition
  • f graft
  • Revascularization;
  • Reinnervation
  • Amyloid deposits

SHORT TERM

  • Ability to induce

normoglycemia

  • β-cells
  • Other cells
  • Hormone release
slide-10
SLIDE 10

Experimental Transplantation

LONG TERM

  • Cellular composition
  • f graft
  • Revascularization;
  • Reinnervation
  • Amyloid deposits

SHORT TERM

  • Ability to induce

normoglycemia

  • β-cells
  • Other cells
  • Hormone release
slide-11
SLIDE 11

Cellular Composition

  • Immunostaining of histological sections
  • Evaluation of number of different cell

types and degree of fibrosis

  • Fibroblasts/myofibroblasts (stellate cells)
  • Macrophages/Dendritic cells
  • Nerve cells/Schwanns cells
  • Endothelial cells/pericytes
slide-12
SLIDE 12

Cellular Composition

  • Immunostaining of histological sections
  • Evaluation of number of different cell

types and degree of fibrosis

  • Fibroblasts/myofibroblasts (stellate cells)
  • Macrophages/Dendritic cells
  • Nerve cells/Schwanns cells
  • Endothelial cells/pericytes
slide-13
SLIDE 13

Endothelial Cells

  • Vascular density, number of endothelial cells
  • (Blood perfusion)
  • pO2
  • Metabolism
  • Capillary blood pressure
  • Lymphatics
  • Vascular dysfunction
slide-14
SLIDE 14

Day 0-1 Post-Tx

Apoptosis β-cells Necrosis O2, nutrients Insulin, metabolites Davalli et al, Diabetes 45:1161, 1996

slide-15
SLIDE 15

Revascularization

  • Revascularization initiated within 1-3 days and

concluded within 7-14 days. Menger et al Diabetes 38(Suppl 1):199, 1989

  • VASCULOGENESIS

Formation from angioblasts

  • ANGIOGENESIS
  • Sprouting
  • Intussusceptive growth
slide-16
SLIDE 16

Vascular Density

  • Bandeiraea

simplicifolia (BS-1)

  • Carlsson et al, JCEM 87:5418,

2002

  • von Willebrand actor
  • Ulex lectin
  • CD31
slide-17
SLIDE 17

Decreased Growth Potential?

Pregnant rats, gestational day 15

Johansson M et al, FASEB J, 19: A1713, 2005

slide-18
SLIDE 18

Improve Islet Revascularization

  • Stimulation of Islet Angiogenesis

Pro-angiogenic factors, e.g VEGF, FGF, HGF, MMP-9

+

Angiostatic factors e.g. α1- antitrypsin, endostatin, thrombospondins,TIMPs

  • Vasir et al, Diabetologia 43:763,

2000 Vasir et al, Transplantation 71:924, 2001 Bergers et al, Nat Cell Biol 2:737, 2000 Lou et al, Diabetes 48:1773, 1999 Tillmar and Welsh JOP 5:81, 2004 Mattsson et al, Pancreatology, in press

slide-19
SLIDE 19

Vascular Organization

Bonner-Weir and Orci, Diabetes 31:883, 1982

slide-20
SLIDE 20

In Vivo Microscopy

In vivo microscopy with Evans Blue

slide-21
SLIDE 21

Endothelial Cells

  • Vascular density, number of endothelial cells
  • (Blood perfusion)
  • pO2
  • Metabolism
  • Capillary blood pressure
  • Lymphatics
slide-22
SLIDE 22

Blood Perfusion

  • In vivo microscopy with cross correlation
  • Laser-Doppler flowmetry
  • Hydrogen gas clearance
  • All these techniques can be used on the

same graft

slide-23
SLIDE 23

Endothelial Cells

  • Vascular density, number of endothelial cells
  • (Blood perfusion)
  • pO2
  • Metabolism
  • Capillary blood pressure
  • Lymphatics
slide-24
SLIDE 24

Microdialysis

Diameter 200 µm

slide-25
SLIDE 25

Anaerobic Metabolism

One-month-old islet graft

non-diabetic diabetic

Carlsson et al, Am J Physiol 284:E499, 2003 Carlsson et al, Surgery 132:487, 2002

slide-26
SLIDE 26

Endothelial Cells

  • Vascular density, number of endothelial cells
  • (Blood perfusion)
  • pO2
  • Metabolism
  • All these parameters can be studied in the

same graft

slide-27
SLIDE 27

Experimental Transplantation

LONG TERM LONG TERM

  • Cellular

Cellular composition composition

  • f
  • f graft

graft

  • Revascularization

Revascularization; ;

  • Reinnervation

Reinnervation

  • Amyloid

Amyloid deposits SHORT TERM

  • Ability to induce

normoglycemia

  • Surviving β-cells
  • Other cells
  • Hormone release

deposits

slide-28
SLIDE 28

Studies Of Hormone Release

  • Ability to induce normoglycemia
  • Removal of graft and in vitro perifusion

(excludes livers)

  • Perfusion of graft-bearing organ (graft

vasculature)

  • The latter two allows for studies also of

glucagon and somatostatin

slide-29
SLIDE 29

Kidney Perfusion

slide-30
SLIDE 30

Insulin Release Human Islets

  • Biphasic release from

islets in normoglycemic recipients

  • Impaired release in

hyperglycemic recipients

  • Jansson et al; J Clin Invest

96:721, 1995

slide-31
SLIDE 31

Retrieved Islets from Liver

One-month-old islet grafts

Control Islets Retrieved Islets

Retrieved islet visualized by Neutral Red Mattsson et al, Diabetes 53: 948, 2004

slide-32
SLIDE 32

Intrahepatic Graft

  • Revascularization
  • ccurs from hepatic

artery, and only to a minor extent from portal vein

Andersson et al, Diabetes 38(Suppl 1): 192, 1989

slide-33
SLIDE 33

Liver Vascular Anatomy

Botini et al, Liver Int 25:861, 2005

slide-34
SLIDE 34

Intrahepatic Grafts

  • Morphological studies to asses the

degree of fragmentation

  • New in vivo imaging techiques;
  • MRI
  • Optiplex
slide-35
SLIDE 35

Experimental Transplantation

LONG TERM

  • Cellular composition
  • f graft
  • Revascularization;
  • Reinnervation
  • Amyloid deposits

SHORT TERM

  • Ability to induce

normoglycemia

  • Surviving β-cells
  • Other cells
  • Hormone release
slide-36
SLIDE 36

Islet Amyloid

Westermark et al; Metabolism 48:448, 1999

slide-37
SLIDE 37

Amyloid Deposits

  • Amyloid occurs in 73% of human islet

grafts within 2 weeks after implantation into nude mice (Westermark et al; Metabolism 48:448,

1999)

  • Initially amyloid is formed

intracellularly (Westermark et al; Upsala J med Sci

108:193, 2003)

slide-38
SLIDE 38

Conclusion

  • Experimental islet transplantation of

human islets offers unique possibilities to assess graft function in both the short and long term perspective

slide-39
SLIDE 39

Acknowledgements

  • Arne Andersson
  • Birgitta Bodin
  • Per-Ola Carlsson
  • Åsa Johansson
  • Magnus Johansson
  • Cecilia Johnsson
  • Caroline Kampf
  • Örjan Källskog
  • Joey Lau
  • Göran Mattsson
  • Astrid Nordin
  • Johan Olerud
  • Richard Olsson
  • Fredrik Palm
  • Lisbeth Sagulin
  • Eva Törnelius