Diabetes, Vol 47, Issue 10 1586-1593, Copyright © 1998 by American Diabetes Association
Capillary blood pressure in syngeneic rat islets transplanted under the renal capsule is similar to that of the implantation organ
PO Carlsson, L Jansson, A Andersson and O Kallskog
Department of Medical Cell Biology, Uppsala University, Sweden. per-ola.carlsson@medcellbiol.uu.se
The aim of the present study was to measure capillary blood pressure and
interstitial pressure in transplanted pancreatic islets and to correlate
these measurements to capillary and tubular pressures in the adjacent
kidney. For this purpose, 250 syngeneic islets were implanted under the
renal capsule of WF rats and studied 1, 2, or 6 months after
transplantation. Some of the animals studied after 1 and 2 months were
streptozotocin (STZ)-induced diabetic. Measurements were performed during
basal conditions or after an acute glucose-stimulation of insulin release.
The hydrostatic pressures were determined in vivo by direct micropuncture.
The islet transplant capillary pressure in normoglycemic animals was 6.9
+/- 0.4 mmHg (n = 9), 10.0 +/- 0.8 mmHg (n = 7), and 12.4 +/- 0.8 mmHg (n =
7) when measured 1, 2, and 6 months after implantation, respectively.
Previous data from our laboratory showed that the normal capillary pressure
of native rat pancreatic islets is approximately 3 mmHg. The blood pressure
in kidney peritubular capillaries was 10-12 mmHg in both transplanted and
control animals. Islet transplant interstitial pressures were 4-6 mmHg in
the normoglycemic recipients at 1, 2, and 6 months after transplantation.
Acute glucose stimulation had no effect on islet transplant interstitial
pressure or peritubular or transplant capillary blood pressures. Capillary
pressures in the islet grafts were slightly increased 1 month after
transplantation in STZ-induced diabetic rats, and this was associated with
an increased blood perfusion of the transplants. However, 2 months after
transplantation there were no differences in transplant capillary blood
pressure between diabetic and normoglycemic animals. The graft interstitial
pressure was, on the contrary, decreased in the diabetic animals 2 months
after transplantation. We concluded that the capillary blood pressure in
islets implanted under the renal capsule was similar to that of the
implantation organ, which was three to four times higher than that normally
found in native islets.