Possible Strategies to Reduce the Tumorigenic Risk of Reprogrammed Normal and Cancer Cells.

The reprogramming of somatic cells to pluripotent stem cells has immense potential for use in regenerating or redeveloping tissues for transplantation, and the future application of this method is one of the most important research topics in regenerative medicine. These cells are generated from normal cells, adult stem cells, or neoplastic cancer cells. They express embryonic stem cell markers, such as OCT4, SOX2, and NANOG, and can differentiate into all tissue types in adults, both in vitro and in vivo. However, tumorigenicity, immunogenicity, and heterogeneity of cell populations may hamper the use of this method in medical therapeutics. The risk of cancer formation is dependent on mutations of these stemness genes during the transformation of pluripotent stem cells to cancer cells and on the alteration of the microenvironments of stem cell niches at genetic and epigenetic levels. Recent reports have shown that the generation of induced pluripotent stem cells (iPSCs) derived from human fibroblasts could be induced using chemicals, which is a safe, easy, and clinical-grade manufacturing strategy for modifying the cell fate of human cells required for regeneration therapies. This strategy is one of the future routes for the clinical application of reprogramming therapy. Therefore, this review highlights the recent progress in research focused on decreasing the tumorigenic risk of iPSCs or iPSC-derived organoids and increasing the safety of iPSC cell preparation and their application for therapeutic benefits.

Safety and toxicological evaluation of a novel, fermented, peptide-enriched, hydrolyzed swine placenta extract powder.

Placenta is an important organ that connects the developing fetus to allow nutrient uptake, antibody provisions and gas exchange via the blood supply of the mother. We developed a novel, standardized, stable, water-soluble, peptide-enriched hydrolyzed, Horus fermented placenta powder (HFPEP) from healthy, pathogen-free, swine placenta. Earlier studies demonstrated that HFPEP significantly improves physical fatigue, hepatic functions and repair of muscle fibers. We examined the broad safety of HFPEP in various toxicology models in Good Laboratory Practices-approved laboratories. The acute oral toxicity study was conducted in female Sprague-Dawley rats, and the acute oral LD50 was found to be greater than 5000 mg/kg body weight. Ames' bacterial reverse mutation assay was conducted to determine the ability of HFPEP to induce reverse mutation at selected histidine loci in five tester strains of Salmonella typhimurium viz. TA1535, TA1537, TA98, TA100 and TA102 in the presence and absence of a metabolic activation system (S9) at the doses of 50, 15, 4.5, 1.35 and 0.41 mg/ml. No mutagenic potential was observed. Mutagenic potential was also evaluated using in vivo micronucleus test, and no mutagenic potential of HFPEP was observed. Repeated dose 28-d oral toxicity study was performed in male and female rats with 14-d recovery period at the dose levels of 250, 500 or 1000 mg/kg. No abnormal clinical signs or toxicity were detected. No observed adverse effect level of HFPEP was found to be greater than 1000 mg/kg body weight. These studies affirm that HFPEP has broad spectrum safety for human consumption.

Crystallization of the terminal oxygenase component of biphenyl dioxygenase derived from Rhodococcus sp. strain RHA1.

The terminal oxygenase component of the biphenyl dioxygenase (BphA1A2 complex) was over-expressed with a novel over expression system in recombinant Rhodococcus strain and purified. The purified enzyme has been crystallized by the hanging drop vapor diffusion method and subjected to X-ray diffraction analysis. The crystals belong to the tetragonal system in the space group P4(1)2(1)2 or P4(3)2(1)2 and diffract to better than 2.2A resolution.

Iontophoresis promotes percutaneous absorption of L-ascorbic acid in rat skin.

BACKGROUND: Percutaneous absorption of ascorbic acid is limited by its impermeability and instability. OBJECTIVE: We attempted to improve the percutaneous absorption of ascorbic acid by use of iontophoresis after topical application of ascorbic acid. METHODS: Radioactivities extracted from epidermal, dermal and blood compartments after topical application of [14C]ascorbic acid was measured in the presence or absence of iontophoresis. Autoradiography was also performed to study the histological distribution of the radioactivity of ascorbic acid. RESULTS: Iontophoresis greatly enhanced percutaneous absorption of [14C]ascorbic acid in the rat skin. Radioactive ascorbic acid in the dermis reached a maximum level at 1 h after application whereas, in the topical application method, the uptake of ascorbic acid in both epidermis and dermis was quite low. Autoradiography of skin specimens indicated that iontophoresis accelerated the absorption of ascorbic acid through both transepidermal and pilo-sebaceous routes. CONCLUSION: Iontophoretic delivery system of ascorbic acid may provide a more efficient tool for its percutaneous absorption than a simple topical application.