Mitomycin C: a promising agent for the treatment of canine corneal scarring

Objective  To evaluate the safety and efficacy of mitomycin C (MMC) in prevention of canine corneal scarring.

Methods  With an in vitro approach using healthy canine corneas, cultures of primary canine corneal fibroblasts or myofibroblasts were generated. Primary canine corneal fibroblasts were obtained by growing corneal buttons in minimal essential medium supplemented with 10% fetal bovine serum. Canine corneal myofibroblasts were produced by growing cultures in serum-free medium containing transforming growth factor β1 (1 ng/mL). Trypan blue assay and phase-contrast microscopy were used to evaluate the toxicity of three doses of MMC (0.002%, 0.02% and 0.04%). Real-time PCR, immunoblot, and immunocytochemistry techniques were used to determine MMC efficacy to inhibit markers of canine corneal scarring.

Results  A single 2-min treatment of 0.02% or less MMC did not alter canine corneal fibroblast or keratocyte phenotype, viability, or growth. The 0.02% dose substantially reduced myofibroblast formation (up to 67%; P < 0.001), as measured by the change in RNA and protein expression of fibrosis biomarkers (α-smooth muscle actin and F-actin).

Conclusion  This in vitro study suggests that a single 2-min 0.02% MMC treatment to the canine corneal keratocytes is safe and may be useful in decreasing canine corneal fibrous metaplasia. In vivo studies are warranted.

Electrical Stimulation of Myoblast Proliferation and Differentiation on Aligned Nanostructured Conductive Polymer Platforms

In this study, nanostructured conductive platforms synthesized from aligned multiwalled carbon nanotubes and polypyrrole are investigated as myo-regenerative scaffolds. Myotube formation follows a linear path on the platforms coinciding with extent of nanotopography. In addition, electrical stimulation enhances myo-nuclear number and differentiation. These studies demonstrate that conductive polymer platforms can be used to influence muscle cell behaviour through nanostructure and electrical stimulation.

The evolution of nitric oxide signalling in vertebrate blood vessels

Nitric oxide is one of the most important signalling molecules involved in the regulation of physiological function. It first came to prominence when it was discovered that the vascular endothelium of mammals synthesises and releases nitric oxide (NO) to mediate a potent vasodilation. Subsequently, it was shown that NO is synthesised in the endothelium by a specific isoform of nitric oxide synthase (NOS) called NOS3. Following this discovery, it was assumed that an endothelial NO/NOS3 system would be present in all vertebrate blood vessels. This review will discuss the latest genomic, anatomical and physiological evidence which demonstrates that an endothelial NO/NOS3 signalling is not ubiquitous in non-mammalian vertebrates, and that there have been key evolutionary steps that have led to the endothelial NO signalling system being a regulatory system found only in reptiles, birds and mammals. Furthermore, the emerging role of nitrite as an endocrine source of NO for vascular regulation is discussed.