Biomedical Engineering Reference
In-Depth Information
affecting the patient's quality of life. In addition to improvements of
surgical techniques, various biological sealants have been developed
to prevent postoperative air leaks; however, there are some problems
with these sealants, and no therapy is perfect. Our laboratory has
focused on the flexibility and robustness of cell sheets and applied
cell sheet engineering to the therapy of postoperative lung air leak
[52, 53]. An autologous dermal fibroblast sheet has been evaluated
in several visceral pleural injury animal models. Skin tissue-derived
fibroblast sheets are easily to handle and apply during surgical
procedures. The dermal fibroblast sheet adheres rapidly (within 5
min) and stably to the lung surface without suturing. In an air leak
porcine model, a fibroblast sheet immediately after transplantation
showed stable closure of the air leaks against an airway pressure of
up to 25 cm H
O. Transplanted fibroblast sheets can be sufficiently
responsive to lung respiration movement, and no recurrence of the
air leaks was observed during one month (follow-up period) after
transplantation. The result shows that fibroblast sheets can play an
important role as a sealant for lung air leaks. On the basis of these
encouraging results in animal models, a clinical trial for treating lung
air leaks using autologous cell sheets is currently being prepared.
2
4b.3.7
Pancreatic Islet Cell Sheets for Curing Diabetes
Mellitus
Diabetes mellitus usually leads to hyperglycemia, which may cause
various diseases, including cerebrovascular disease, cardiovascular
disease, ketoacidosis, renal failure, and blindness [54]. Several
therapies, including transplantation of islet tissue or islet cells,
have been attempted but with mixed results [55]. Our laboratory
has also proposed a novel cell therapy using cell sheet-based tissue
engineering for treating diabetes mellitus [56, 57]. Rat pancreatic
islet-derived cells cultured on a temperature-responsive culture
surface, precoated with a cell adhesion molecule, laminin-5, can
be recovered as an islet cell sheet. Because the recovered islet cell
sheet preserves the functions of native islet cells, including (1) the
secretion of insulin and glucagon and (2) glucose-dependent insulin
secretion, transplantation of islet cell sheets acts as a surrogate
for diseased islet tissues. Using streptozotocin-induced diabetes
in severe combined immunodeficiency (SCID) mice, islet cell
sheets were transplanted into the subcutaneous space to examine
