Mechanobiologically induced bone-like nodules: Matrix characterization from micro to nanoscale.

In bone tissue engineering, stem cells are known to form inhomogeneous bone-like nodules on a micrometric scale. Herein, micro- and nano-infrared (IR) micro-spectroscopies were used to decipher the chemical composition of the bone-like nodule. Histological and immunohistochemical analyses revealed a cohesive tissue with bone-markers positive cells surrounded by dense mineralized type-I collagen. Micro-IR gathered complementary information indicating a non-mature collagen at the top and periphery and a mature collagen within the nodule. Atomic force microscopy combined to IR (AFM-IR) analyses showed distinct spectra of "cell" and "collagen" rich areas. In contrast to the "cell" area, spectra of "collagen" area revealed the presence of carbohydrate moieties of collagen and/or the presence of glycoproteins. However, it was not possible to determine the collagen maturity, due to strong bands overlapping and/or possible protein orientation effects. Such findings could help developing protocols to allow a reliable characterization of in vitro generated complex bone tissues.

Osteoinductive Material to Fine-Tune Paracrine Crosstalk of Mesenchymal Stem Cells With Endothelial Cells and Osteoblasts.

While stem cell/biomaterial studies provide solid evidences that biomaterial intrinsic cues deeply affect cell fate, current strategies tend to neglect their effects on mesenchymal stem cells (MSCs) secretory activities and resulting cell-crosstalks. The present study aims to investigate the impact of bone-mimetic material (B-MM), with intrinsic osteoinductive property, on MSCs mediator secretions; and to explore underlying effects on cells involved in bone regeneration. Human MSCs were cultured, on B-MM, made from inorganic calcium phosphate supplemented with chitosan and hyaluronic acid biopolymers. Collected MSCs culture media were assessed for mediators release quantification and used further to stimulate endothelial cells (ECs) and alveolar bone derived osteoblasts (OBs). Without osteogenic supplements, MSCs committed into bone lineage forming thus 3D bone-like nodules after 21 days. Despite a weak percentage of cell commitment, our data elucidate new aspects of osteoinductive material effect on MSCs functions through the regulation of the secretion of mediators involved in bone regeneration and subsequently the MSCs/ECs indirect crosstalk with osteogenesis-boosting effect. Using MSCs culture media, we demonstrate a large potential of osteoinductive materials and MSCs in bone regenerative medicine. Such strategies could help to address some insights in cell-free therapies using MSCs derived media.

Combining Calcium Phosphates with Polysaccharides: A Bone-Inspired Material Modulating Monocyte/Macrophage Early Inflammatory Response.

The use of inorganic calcium/phosphate supplemented with biopolymers has drawn lots of attention in bone regenerative medicine. While inflammation is required for bone healing, its exacerbation alters tissue regeneration/implants integration. Inspired by bone composition, a friendly automated spray-assisted system was used to build bioactive and osteoinductive calcium phosphate/chitosan/hyaluronic acid substrate (CaP-CHI-HA). Exposing monocytes to CaP-CHI-HA resulted in a secretion of pro-healing VEGF and TGF-ß growth factors, TNF-α, MCP-1, IL-6 and IL-8 pro-inflammatory mediators but also IL-10 anti-inflammatory cytokine along with an inflammatory index below 1.5 (versus 2.5 and 7.5 following CaP and LPS stimulation, respectively). Although CD44 hyaluronic acid receptor seems not to be involved in the inflammatory regulation, results suggest a potential role of chemical composition and calcium release from build-up substrates, in affecting the intracellular expression of a calcium-sensing receptor. Herein, our findings indicate a great potential of CaP-CHI-HA in providing required inflammation-healing balance, favorable for bone healing/regeneration.

Chemical composition, in vitro cytotoxicity and anti-free radical properties of six extracts from Lebanese Trigonella berythea Boiss.

This study represents an original work aimed to recognize the main constitution of Trigonella berythea. The total phenolic content and total flavonoid content of leaves and stems of T. berythea have been estimated. An extraction and purification of phenolic mixture compounds from the leaves and stems of this plant have been performed and their antioxidant potential using the DPPH, H2O2 and chelating of ferrous ions tests has been evaluated. Then, their cytotoxicity on the MCF7 breast cancer cell line by the XTT Cell Viability technique has been studied. Our results demonstrated that leaves of T. berythea had higher total phenolic content and total flavonoid content than stems. On the other hand, the six extract from leaves and stems of this plant demonstrated a high antioxidant potential reaches more than 80%. Also, extracts from leaves of T. berythea had the highest inhibitory effect on MCF7 and U937 cell growth than that of stems. This inhibition was more than 60% for all extracts. These results provide new insight into the health functions of leaves and stems and demonstrate that T. berythea extracts can potentially have health benefits.

Chemical composition and antioxidant activity of a Lebanese plant Euphorbia macroclada schyzoceras.

OBJECTIVE: To determine the chemical composition, total phenolic and total flavonoid contents of the crude extracts from leaves and stems of a Lebanese plant Euphorbia macroclada schyzoceras (E. macroclada), and to evaluate their antioxidant potential using DPPH, H2O2, and chelating of ferrous ions tests. METHODS: Quantification of the total phenolic and total flavonoid contents of the crude extracts from leaves and stems and the antioxidant activities were evaluated using spectrophotometric analyses. The chemical composition has been estimated using different techniques such as IR, LC/MS and NMR. RESULTS: Ethanolic extract from leaves of E. macroclada was better than aqueous extract and showed higher content in total phenolic and total flavonoid than found in the stems. On the other hand, using DPPH and H2O2 tests, this extract from leaves showed higher antioxidant capacity than aqueous extract. However, using the chelating of ferrous ions test, the antioxidant activity of the aqueous extract of both stems and leaves was stronger than that of ethanolic once. The chemical composition of the whole plant showed the presence of some aromatic compounds and fatty acids. CONCLUSIONS: Both ethanolic and water extracts from both parts of this plant are effective and have good antioxidant power. So, this plant can be used in the prevention of a number of diseases related to oxidative stress.

The antioxidant effect of plums and polyphenolic compounds against H(2)O(2)-induced oxidative stress in mouse blood granulocytes.

Epidemiological and scientific research has contributed to the identification of the key role of dietary antioxidants in maintaining human health by preventing oxidative damage to cellular components. The antiradical activity of seven varieties of plums and their protective effects against oxidative stress were comparatively evaluated in mouse granulocytes in this study using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) test and a cellular test. The class of phytochemical compounds responsible for the main antioxidant capacities observed was also investigated. The ABTS and cellular tests revealed that the total antioxidant capacities, expressed as vitamin C equivalents, ranged from 691.2 to 2,164.64 mg and from 613.98 to 2,137.59 mg per 100 g of fresh weight, respectively, suggesting that plums are rich in natural antioxidants and appreciably protect granulocytes from oxidative stress. Our results showed a linear correlation between either total phenolic or flavonoid contents and total antioxidant capacity, revealing that these compounds contribute significantly to the antioxidant activity of plums. The major polyphenolics in plums, identified and quantified using reversed-phase high-performance liquid chromatography, were tested to evaluate their protective effect on peripheral blood granulocytes from oxidative stress. The results suggest that individual polyphenolics contribute directly to the total protective effect of plums.

Chlorogenic acid, a polyphenol from Prunus domestica (Mirabelle), with coupled anxiolytic and antioxidant effects.

BACKGROUND: Oxidative stress is linked to neurodegenerative diseases, cancer, cardiovascular diseases and to some behaviors, such as anxiety and depression. In particular, recent research observed a close relationship between oxidative stress and anxiety. METHODS: We investigated the anxiolytic effect of chlorogenic acid, a dietary antioxidant present in fruits, in mouse models of anxiety including the light/dark test, the elevated plus maze and the free exploratory test. Moreover, the antioxidative effect of chlorogenic acid on peripheral blood granulocytes was investigated. RESULTS: Chlorogenic acid (20 mg/kg) induced a decrease in anxiety-related behaviors suggesting an anxiolytic-like effect of this polyphenol. The anti-anxiety effect was blocked by flumazenil suggesting that anxiety is reduced by activation of the benzodiazepine receptor. In vitro, chlorogenic acid protected granulocytes from oxidative stress. CONCLUSIONS: Chlorogenic acid is one of the most abundant polyphenols in fruits. We demonstrated in vivo and in vitro for the first time, that chlorogenic acid has anxiolytic effects coupled with antioxidant activity. Thus, fruits such as plums (Mirabelle), apples and cherries may provide health-promoting advantages to consumers.