Cell adhesion and tissue response to hydroxyapatite nanocrystal-coated poly(L-lactic acid) fabric

Yanagida H, Okada M, Masuda M, Ueki M, Narama I, Kitao S, Koyama Y, Furuzono T, Takakuda K.
Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka , Japan.

Cell adhesion and tissue response to poly(l-lactic acid) (PLLA) fabric coated with nanosized hydroxyapatite (HAp) crystals were studied. The HAp nanocrystals were prepared by the wet chemical process followed by calcination at 800 degrees C with an anti-sintering agent to prevent calcination-induced sintering.

After the PLLA fabric was hydrolyzed with an alkaline aqueous solution, the HAp nanocrystals were coated via ionic interaction between the calcium ions on the HAp and the carboxyl groups on the alkali-treated PLLA. The PLLA surface uniformly coated with the HAp nanocrystals was observed by scanning electron microscope. The ionic interaction between the HAp and the PLLA was estimated by FT-IR. Improved cell adhesion to the HAp nanocrystal-coated surface was demonstrated by in vitro testing using a mouse fibroblast cell line L929.

Furthermore, reduced inflammatory response to the HAp nanocrystal-coated PLLA fabric (as compared with a non-treated one) was confirmed by a subcutaneous implantation test with rats. Thus the HAp nanocrystal-coated PLLA developed has possible efficacy as an implant material in the fields of general and orthopedic surgery, and as a cell scaffold in tissue engineering

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content

ABSTRACT: BACKGROUND: Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content.

METHODS: In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20~30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate.

Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (10;8~10;9 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks.

RESULTS: B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p<0.05), and slightly increased serum HDL. B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities.

CONCLUSIONS: Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation .

Lee DK, Jang S, Baek EH, Kim MJ, Lee KS, Shin HS, Chung MJ, Kim JE, Lee KO, Ha NJ.