Surface properties and implantation site affect the capsular fibrotic overgrowth.
Transplantation of encapsulated pancreatic islets is a promising approach for the treatment of type 1 diabetes. Large-scale application of this technique, however, is hampered by insufficient biocompatibility of the capsules. In this study, we have evaluated the biocompatibility of a new synthetic material with six different chemical groups on their surface (amino, carboxy-sulfate, carboxylate, hydroxylate, sulfate, and PMMA) used for the fabrication of the microcapsules. Eight Lewis rats were inoculated with a suspension of empty capsules made for each candidate material in the retroperitoneal ileopsoas muscle and renal subcapsular space. Four weeks later kidney and muscle containing the capsules were explanted, paraffin embedded, sectioned and stained with Sirius Red and Masson's Trichrome for histological analysis. The amount of fibrosis was also ultrastructurally evaluated with scanning electron microscopy. The samples were then subjected to digitalized quantitative analysis using specific software to determine the degree of fibrotic overgrowth. The quantification of collagen deposition, calculated in proximity of the microcapsules, was expressed as a percentage of the total area and can be considered a good index for the biocompatibility, an essential prerequisite for functional pancreatic islet transplantation. The results show that subcapsular renal space is the best implantation site and the positive surface charge induces a more intense collagen synthesis.
Bakeine
G J
GJ
Department of Physics and Nanotechnology, University of Trieste, Italy.
Bertolotti
A
A
Department of Animal Biology, University of Pavia, Italy.|Department of Histochemistry and Cytochemistry, IGM-CNR, Italy.
Latina
M
M
Department of Surgery, University of Pavia School of Medicine and I.R.C.C.S. Policlinico San Matteo Hospital, Italy.
Congiu
T
T
Laboratory of Human Morphology, University of Insubria, Varese, Italy.
Prati
U
U
Institute of General and Transplantation Surgery, Madonna delle Grazie Hospital, Matera, Italy.
Roveda
L
L
Institute of General and Transplantation Surgery, Madonna delle Grazie Hospital, Matera, Italy.
Trotta
F
F
Institute of General and Transplantation Surgery, Madonna delle Grazie Hospital, Matera, Italy.
Tormen
M
M
LILIT group, TASC-INFM Nanolithography Beamline at Elettra Synchrotron Light Source, Basovizza, Trieste, Italy.
Fabrizio
E Di
ED
LILIT group, TASC-INFM Nanolithography Beamline at Elettra Synchrotron Light Source, Basovizza, Trieste, Italy.
Carlini
G
G
LILIT group, TASC-INFM Nanolithography Beamline at Elettra Synchrotron Light Source, Basovizza, Trieste, Italy.
Facoetti
A
A
Department of Animal Biology, University of Pavia, Italy.|Department of Histochemistry and Cytochemistry, IGM-CNR, Italy.
Nano
R
R
Department of Animal Biology, University of Pavia, Italy.|Department of Histochemistry and Cytochemistry, IGM-CNR, Italy.
D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology / Q000628:therapy; D005355:Fibrosis; D016381:Islets of Langerhans Transplantation; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D013499:Surface Properties