Gene transfer of insulin-like growth factor-I providing neuroprotection after spinal cord injury in rats

alpha-melanocyte-stimulating hormone gene transfer attenuates inflammation after bile duct ligation in the rat

Cholestasis occurs in a wide variety of human liver diseases, and hepatocellular injury is an invariant feature of cholestasis causing liver dysfunction and inflammation, promoting fibrogenesis, and ultimately leading to liver failure. alpha-Melanocyte-stimulating hormone (alpha-MSH) is a potent anti-inflammatory agent in many models of inflammation, suggesting that it inhibits a critical step common to different forms of inflammation. The aim of this study was to investigate whether the gene transfer of alpha-MSH could attenuate hepatic inflammation after bile duct ligation in the rat. Studies were performed in bile duct-ligated (BDL) rats. Hydrodynamic-based gene transfection with alpha-MSH plasmid via rapid tail vein injection was performed 30 min after ligation of bile duct. The endpoints were studied as markers of inflammation 7 days after bile duct ligation. alpha-MSH expression in liver via a single administration of naked plasmid was demonstrated. Liver inflammation index, including neutrophil infiltration and serum alanine aminotransferase, were significantly reduced in alpha-MSH gene transfer rats. Markers for liver inflammation, including expression of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and inducible NO synthase (iNOS) mRNA, as assessed by real-time PCR, were also attenuated by alpha-MSH gene therapy. Expression of iNOS protein in liver diminished after alpha-MSH gene transfer. Consistent with these data, hepatic stellate cells (HSC) and Kupffer cells were markedly inhibited in alpha-MSH gene-treated rats. Our findings show that gene transfer of alpha-MSH could attenuate hepatic inflammation after bile duct ligation in the rat.

Cellular approaches for stimulating CNS remyelination

Myelination is critical for the normal functioning of the vertebrate nervous system. In the CNS, myelin is produced by oligodendrocytes, and the loss of oligodendrocytes and myelin results in severe functional impairment. Although spontaneous remyelination occurs in chronic demyelinating diseases such as multiple sclerosis, the repair process eventually fails, often resulting in long-term disability. Two distinct general approaches can be considered to promote myelin repair. In one the target is stimulation of the endogenous myelin repair process through delivery of growth factors, and in the second the target is augmentation of the repair process through the delivery of exogenous cells with myelination potential. In both cases, effective treatment of diseases such as multiple sclerosis requires modulation of the immune system, since demyelination is associated with specific immunological activation. Recent studies have shown that some populations of stem cells, including mesenchymal stem cells, have the capacity of promoting endogenous myelin repair and modulating the immune response, prompting an assessment of their use as therapy in demyelinating diseases such as MS. Other types of demyelinating disorders, such as the leukodystrophies, may require multiple repair strategies including both replacement of dysfunctional cells and delivery or supplementation of growth factors, immune modulators or metabolic enzymes. Here we discuss the use of stem cells for the treatment of demyelinating diseases. While the current number of stem cell-based clinical trials for demyelinating diseases is limited, this is likely to increase significantly in the next few years, and a clear understanding of the applicability, limitations and underlying mechanisms mediating stem cell repair is critical.