Comparative study of regenerative potential of beta cells from young and aged donor mice using a novel islet transplantation model.
BACKGROUND
The effect of ageing on beta-cell regeneration under hyperglycemia has not been defined and may best be addressed using a unique islet-transplantation model.


METHODS
Streptozotocin-induced diabetic FVB/NJ mice were rendered normoglycemic with a therapeutic mass of syngeneic islets implanted in the epididymal fat pad, followed by a subrenal capsular implantation of a subtherapeutic mass of 25 islets from young (3 months) or old (24 months) mice. Three weeks after the second transplant, the islet containing fat pad was removed to reintroduce hyperglycemia. Bromodeoxyuridine (BrdU) was provided to mice continuously in drinking water. Islet grafts under the kidney capsule were harvested at different time points and examined for markers of beta-cell regeneration by immunohistochemistry.


RESULTS
After a 7-day labeling, BrdU was detected in 54.2% or 53.0% beta cells of the young or old islet grafts, respectively, under hyperglycemia when compared with 3.3% in grafts under normoglycemia. Ki67-positive beta cells were enhanced from a baseline level of 0.5% to 5.2% (young islets) or 4.0% (old islets) on day 7 of hyperglycemia, then decreased to 2.4% on day 21, at which time point an accumulative 75.3% or 66.8% BrdU-positive beta cells was detected in the young or old grafts, respectively. No statistic difference in the percent BrdU- or Ki67-positive beta cells was detected between the young and aged grafts at any time point studied.


CONCLUSIONS
These data reveal that islet beta cells from aged mice can replicate in response to hyperglycemia after transplantation at a capacity and frequencies not significantly different than that of the young adult ones.
Chen
Xiaojuan
X
Department of Surgery, Division of Organ Transplantation, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. x-chen@northwestern.edu
Zhang
Xiaomin
X
Chen
Fei
F
Larson
Courtney S
CS
Wang
Ling-Jia
LJ
Kaufman
Dixon B
DB
D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D049109:Cell Proliferation; D003921:Diabetes Mellitus, Experimental / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006943:Hyperglycemia / Q000473:pathology / Q000503:physiopathology; D050417:Insulin-Secreting Cells / Q000473:pathology / Q000502:physiology*; D016381:Islets of Langerhans Transplantation / Q000473:pathology / Q000502:physiology*; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D051379:Mice; D023421:Models, Animal; D012038:Regeneration / Q000502:physiology*; D014185:Transplantation, Isogeneic
D019394:Ki-67 Antigen; D001973:Bromodeoxyuridine