Mitochondrial oxidative stress, endothelial function and metabolic control in patients with type II diabetes and periodontitis: A randomised controlled clinical trial.

BACKGROUND: Periodontitis (PD) and type 2 diabetes (T2D) are characterized by increased mitochondrial oxidative stress production (mtROS), which has been associated with a greater risk of cardiovascular diseases (CVD). Intensive PD treatment (IPT) can significantly improve endothelial function and metabolic control, although the mechanisms remain unclear. We explored whether, in patients with PD and T2D, changes of mtROS are associated with improvement of endothelial function and metabolic control after IPT. METHODS: 51 patients with T2D and PD were enrolled in a single-blind controlled trial and randomised to either intensive (n = 27) or standard (CPT, n = 24) PD treatment. Levels of mtROS in peripheral blood mononuclear cells (PBMC) were measured using a FACS-based assay at baseline and 24 h, 1 week, 2 and 6 months after PD treatment. Inflammatory cytokines, CVD risk factors, metabolic control and endothelial function were assessed at baseline and 6 months after intervention. RESULTS: After 6 months from PD treatment, the IPT group had lower mtROS (in both the whole PBMC and lymphocytes), circulating levels of HbA1c, glucose, INF-γ, TNF-α (p < 0.05 for all), and improved endothelial function (p < 0.05) compared to the CPT group. There was an association between higher mtROS and lower endothelial function at baseline (r = -0.39; p = 0.01) and, in the IPT group, changes of mtROS were associated with changes of endothelial function (r = 0.41; p < 0.05). CONCLUSIONS: Reduced mtROS is associated with improved endothelial function and accompanied by better metabolic control in patients with T2D and PD. mtROS could represent a novel therapeutic target to prevent CVD in T2D.

Could clinical photochemical internalisation be optimised to avoid neuronal toxicity?

Photochemical Internalisation (PCI) is a novel drug delivery technology in which low dose photodynamic therapy (PDT) can selectively rupture endo/lysosomes by light activation of membrane-incorporated photosensitisers, facilitating intracellular drug release in the treatment of cancer. For PCI to be developed further, it is important to understand whether nerve damage is an impending side effect when treating cancers within or adjacent to nervous system tissue. Dorsal root ganglion (DRG) neurons and their associated satellite glia were subjected to PCI treatment in a 3D co-culture system following incubation with photosensitisers: meso-tetraphenylporphine (TPPS2a) or tetraphenylchlorin disulfonate (TPCS2a) and Bleomycin. Results from the use of 3D co-culture models demonstrate that a cancer cell line PCI30 and satellite glia were more sensitive to PCI than neurons and mixed glial cells, athough neurite length was affected. Neurons in culture survived PCI treatment under conditions sufficient to kill tumour cells, suggesting cancers within or adjacent to nervous system tissue could be treated with this novel technology.

Adapting tissue-engineered in vitro CNS models for high-throughput study of neurodegeneration.

Neurodegenerative conditions remain difficult to treat, with the continuing failure to see therapeutic research successfully advance to clinical trials. One of the obstacles that must be overcome is to develop enhanced models of disease. Tissue engineering techniques enable us to create organised artificial central nervous system tissue that has the potential to improve the drug development process. This study presents a replicable model of neurodegenerative pathology through the use of engineered neural tissue co-cultures that can incorporate cells from various sources and allow degeneration and protection of neurons to be observed easily and measured, following exposure to neurotoxic compounds - okadaic acid and 1-methyl-4-phenylpyridinium. Furthermore, the technology has been miniaturised through development of a mould with 6 mm length that recreates the advantageous features of engineered neural tissue co-cultures at a scale suitable for commercial research and development. Integration of human-derived induced pluripotent stem cells aids more accurate modelling of human diseases, creating new possibilities for engineered neural tissue co-cultures and their use in drug screening.

Embryonic and mature astrocytes exert different effects on neuronal growth in rat ventral mesencephalic slice cultures.

One obstacle with grafting of dopamine neurons in Parkinson's disease is the insufficient ability of the transplant to reinnervate the host striatum. Another issue is the prospective interaction between the donor fetal tissue and the adult astrocytes of the host. To study nerve fiber growth and its interaction with immature/mature astrocytes, ventral mesencephalic (VM) organotypic rat tissue cultures from embryonic days (E) 12, E14, and E18 were studied up to 35 days in vitro (DIV), and co-cultures of E14 VM tissue and mature green fluorescent protein (GFP)-positive astrocytes were performed. Generally, nerve fibers grew from the tissue slice either in association with a monolayer of migrated astroglia surrounding the tissue (glial-associated), or distal to the astroglia as non-glial-associated outgrowth. The tyrosine hydroxylase (TH)-positive glial-associated nerve fiber outgrowth reached a plateau at 21 DIV in E12 and E14 cultures. In E18 cultures, TH-positive neurons displayed short processes and migrated onto the astrocytes. While the non-glial-associated nerve fiber outgrowth dominated the E14 cultures, it was found absent in E18 cultures. The GFP-positive cells in the VM and GFP-positive astrocyte co-cultures were generally located distal to the monolayer of migrated fetal astrocytes, a few GFP-positive cells were however observed within the astrocytic monolayer. In those cases TH-positive neurons migrated towards the GFP-positive cells. Both the non-glial- and glial-associated nerve fibers grew onto the GFP-positive cells. Taken together, the glial-associated growth has limited outgrowth compared to the non-glial-associated nerve fibers, while none of the outgrowth types were hampered by the mature astrocytes.

Optimising contraction and alignment of cellular collagen hydrogels to achieve reliable and consistent engineered anisotropic tissue.

Engineered anisotropic tissue constructs containing aligned cell and extracellular matrix structures are useful as in vitro models and for regenerative medicine. They are of particular interest for nervous system modelling and regeneration, where tracts of aligned neurons and glia are required. The self-alignment of cells and matrix due to tension within tethered collagen gels is a useful tool for generating anisotropic tissues, but requires an optimal balance between cell density, matrix concentration and time to be achieved for each specific cell type. The aim of this study was to develop an assay system based on contraction of free-floating cellular gels in 96-well plates that could be used to investigate cell-matrix interactions and to establish optimal parameters for subsequent self-alignment of cells in tethered gels. Using C6 glioma cells, the relationship between contraction and alignment was established, with 60-80% contraction in the 96-well plate assay corresponding to alignment throughout tethered gels made using the same parameters. The assay system was used to investigate the effect of C6 cell density, collagen concentration and time. It was also used to show that blocking α1 integrin reduced the contraction and self-alignment of these cells, whereas blocking α2 integrin had little effect. The approach was validated by using primary astrocytes in the assay system under culture conditions that modified their ability to contract collagen gels. This detailed investigation describes a robust assay for optimising cellular self-alignment and provides a useful reference framework for future development of self-aligned artificial tissue.