Tissue engineering of small intestinal tissue using collagen sponge scaffolds seeded with smooth muscle cells.

In a previously reported attempt to regenerate small intestine with autologous tissues, collagen scaffolds were used without cell seeding or with autologous mesenchymal stem cell seeding. However the regenerated intestine lacked a smooth muscle layer. To accomplish regeneration of a smooth muscle layer, this present study used collagen scaffolds seeded with the smooth muscle cells (SMC) in a canine model. Autologous SMC were isolated from stomach wall and cultured. Two types of scaffolds were fabricated: in SMC (+), cultured SMCs were mixed with collagen solution and poured into a collagen sponge; and in SMC (-), SMCs were omitted. Both scaffolds were implanted into defects of isolated ileum as a patch graft. Animals were euthanized at 4, 8, and 12 weeks; for the last time point, the ileal loop had been reanastomosed at 8 weeks. At 12 weeks, the SMC (-) group showed a luminal surface covered by a regenerated epithelial cell layer with very short villi; however only a thin smooth muscle layer was observed, representing the muscularis mucosae. In the SMC (+) group, the luminal surface was covered completely by a relatively well-developed epithelial layer with numerous villi. Implanted SMCs were seen in the lamina propria and formed a smooth muscle layer. Thus, we concluded that collagen sponge scaffolds seeded with autologous SMCs have a potential for small intestine regeneration.

Intratumoral administration of methotrexate bound to activated carbon particles: antitumor effectiveness against human colon carcinoma xenografts and acute toxicity in mice.

We previously developed a new formulation of methotrexate (MTX) that is adsorbed onto a suspension of activated carbon particles (MTX-CH) and reported the usefulness of local administration in murine tumors. The present study examines the effects of human colon carcinoma (LoVo) xenografts and the acute toxicity of MTX-CH compared with MTX aqueous solution (MTX-AQ) in mice. In therapeutic experiments, LoVo cells were implanted into the backs of BALB/c nude mice. When the cells had developed into tumors, we performed an intratumoral administration of a weekly dose of 30 mg/kg. The MTX concentration in the tumor was compared between the MTX-CH group and MTX-AQ group. In experiments on acute toxicity, MTX-CH and MTX-AQ were injected subcutaneously in BDF1 mice, and intoxication symptoms, changes in body weight, and date of death were recorded. In the therapeutic experiments, intratumoral administration of MTX-CH was much more effective in suppressing the tumor growth compared with MTX-AQ. In experiments of acute toxicity, the death time of the MTX-CH group was delayed to a greater extent, and the 50% lethal dose (LD(50)) values of MTX-CH were lower than those of MTX-AQ. The LD(50) values of MTX-CH are 75 times higher than the efficacious dose of 30 mg/kg. The present results suggest that intratumoral administration of MTX-CH is useful for local therapy and the therapeutic dose of MTX-CH can be safely injected subcutaneously.

[Intratumoral administration of methotrexate bound to activated carbon particles (MTX-CH) inducing antitumor effect in vivo].

Methotrexate is one of the anticancer drugs that can be safely administered subcutaneously, but locally injected MTX in aqueous solution form does not function in the administration site for very long. We developed a new dosage formulation: methotrexate bound to activated carbon particles (MTX-CH), and can report that it controlled tumor growth through its long-acting effect at the administration site. In this study, we investigated the effect of local administration of MTX-CH compared with MTX aqueous solution in tumors from transplanted human colon cancer cells (LoVo) into the back of nude mice. MTX-CH is superior to MTX aqueous solution in terms of its long-acting effect at the administration site and antitumor effect. We suggest that intratumoral injection therapy of MTX-CH is useful for patients in poor condition and with high surgical risk due to cardiac disease or old age, and patients who are diagnosed positive for cancer after endoscopic mucosal resection of early colorectal cancer.