METHODS: The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls).
RESULTS: Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p < 0.05) apoptotic cell death due to DPPH and ABTS by 4 to 5-fold although the activity was less than vitamin C. Based on the DPPH assay, the radical scavenging activity of the extract was higher than phycocyanin and was at least 50% of vitamin C and vitamin E. Based on the ABTS assay, the antioxidant activity of the extract at 50 μmug/mL was as good as vitamin C and vitamin E.
CONCLUSIONS: The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.
METHODS AND RESULTS: We synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate "burst release" and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line.
CONCLUSION: Iron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and tissue.
MAIN BODY: In this review, we summarized the evidence and unique properties of TME in pancreatic cancer that may contribute to its resistance towards immunotherapies as well as strategies to overcome those barriers. We reviewed the current strategies and future perspectives of combination therapies that (1) promote T cell priming through tumor associated antigen presentation; (2) inhibit tumor immunosuppressive environment; and (3) break-down the desmoplastic barrier which improves tumor infiltrating lymphocytes entry into the TME.
CONCLUSIONS: It is imperative for clinicians and scientists to understand tumor immunology, identify novel biomarkers, and optimize the position of immunotherapy in therapeutic sequence, in order to improve pancreatic cancer clinical trial outcomes. Our collaborative efforts in targeting pancreatic TME will be the mainstay of achieving better clinical prognosis among pancreatic cancer patients. Ultimately, pancreatic cancer will be a treatable medical condition instead of a death sentence for a patient.
Materials and methods: QOS collagen nanofibers were electrospun by incorporating various concentrations of QOS (0.1%-10% w/w) and were cross-linked in situ after exposure to ammonium carbonate. The QOS cross-linked scaffolds were characterized and their biological properties were evaluated in terms of their biocompatibility, cellular adhesion and metabolic activity for primary human dermal fibroblasts and human fetal osteoblasts.
Results and discussion: The study revealed that 1) QOS cross-linking increased the flexibility of otherwise rigid collagen nanofibers and improved the thermal stability; 2) QOS cross-linked mats displayed potent antibacterial activity and 3) the biocompatibility of the composite mats depended on the amount of QOS present in dope solution - at low QOS concentrations (0.1% w/w), the mats promoted mammalian cell proliferation and growth, whereas at higher QOS concentrations, cytotoxic effect was observed.
Conclusion: This study demonstrates that QOS cross-linked mats possess anti-infective properties and confer niches for cellular growth and proliferation, thus offering a useful approach, which is important for hard and soft tissue engineering and regenerative medicine.
METHODS: Primary cultures of young, pre-senescent, and senescent fibroblast cells were incubated with γ-tocotrienol for 24 h. The expression levels of ELN, COL1A1, MMP1, CCND1, RB1, and IL6 genes were determined using the quantitative real-time polymerase chain reaction. Cell cycle profiles were determined using a FACSCalibur Flow Cytometer.
RESULTS: The cell cycle was arrested in the G(0)/G(1) phase, and the percentage of cells in S phase decreased with senescence. CCND1, RB1, MMP1, and IL6 were upregulated in senescent fibroblasts. A similar upregulation was not observed in young cells. Incubation with γ-tocotrienol decreased CCND1 and RB1 expression in senescent fibroblasts, decreased cell populations in the G(0)/G(1) phase and increased cell populations in the G(2)/M phase. γ-Tocotrienol treatment also upregulated ELN and COL1A1 and downregulated MMP1 and IL6 expression in young and senescent fibroblasts.
CONCLUSION: γ-Tocotrienol prevented cellular aging in human diploid fibroblasts, which was indicated by the modulation of the cell cycle profile and senescence-associated gene expression.
AIM OF THE STUDY: To investigate the wound healing ability of a concentrated extract of B. orientale in a hydrogel formulation in healing diabetic ulcer wounds.
MATERIALS AND METHODS: The water extract from the leaves of B. orientale was separated from the crude methanolic extract and subjected to flash column chromatography techniques to produce concentrated fractions. These fractions were tested for phytochemical composition, tannin content, antioxidative and antibacterial activity. The bioactive fraction was formulated into a sodium carboxymethylcellulose hydrogel. The extract-loaded hydrogels were then characterized and tested on excision ulcer wounds of streptozotocin-induced diabetic rats. Wound size was measured for 14 days. Histopathological studies were conducted on the healed wound tissues to observe for epithelisation, fibroblast proliferation and angiogenesis. All possible mean values were subjected to statistical analysis using One-way ANOVA and post-hoc with Tukey's T-test (P<0.05).
RESULTS: One fraction exhibited strong antioxidative and antibacterial activity. The fraction was also highly saturated with tannins, particularly condensed tannins. Fraction W5-1 exhibited stronger antioxidant activity compared to three standards (α-Tocopherol, BHT and Trolox-C). Antibacterial activity was also present, and notably bactericidal towards Methicillin-resistant Staphylococcus aureus (MRSA) at 0.25mg/ml. The extract-loaded hydrogels exhibited shear-thinning properties, with high moisture retention ability. The bioactive fraction at 4% w/w was shown to be able to close diabetic wounds by Day 12 on average. Other groups, including controls, only exhibited wound closure by Day 14 (or not at all). Histopathological studies had also shown that extract-treated wounds exhibited re-epithelisation, higher fibroblast proliferation, collagen synthesis, and angiogenesis.
CONCLUSION: The ethnopharmacological effects of using B. orientale as a topical treatment for external wounds was validated and was also significantly effective in treating diabetic ulcer wounds. Thus, B. orientale extract hydrogel may be presented as a potential treatment for diabetic ulcer wounds.