An essay published in Molecular Therapy has managed to repair up to 80% of one type of human butterfly skin that remained grafted onto a mouse. The work uses the new technique of the CRISPR, but only in one of its possibilities: to cut a mutated piece (exon) of the col7A1 gene, which is overexpressed. "That's why it's so effective," says Marcela Ríos, a researcher at CIEMAT (Center for Energy, Environmental and Technological Research). If, instead of cutting, a DNA sequence had to be added, the efficiency would decrease, says the researcher.
Butterfly skin is the common name of a series of rare diseases technically known as epidermolysis bullosa. The name refers to the blisters that appear in those affected, which when exploited cause small injuries and retractions that must be cured (you can use up to four hours a day for it) and that heal very badly. In addition, the deterioration of the skin, the first protection of the human being, can suppose additional problems of infections, and can also affect other organs and cause gastrointestinal ailments, in eyes, larynxes, teeth, haematological problems, generalized superinfections and deterioration of the state general, details the Spanish Federation of Rare Diseases (Feder)
It is estimated that only in Spain there are about a thousand affected, and that in the world one of every 50,000 newborns will develop it, according to the Debra association.
The proven technique addresses one of the variants of this disease, linked to that gene, which makes collagen. It is very frequent among those affected in Spain, but not the only cause, warns the researcher. When the collagen is deficient, the layers of the skin, dermis and epidermis separate, explains the researcher, which causes its fragility. By removing a piece, the molecule fulfills its function of linking the dermal layers.
The scheme of treatment
In the trial, stem cells were taken from an affected skin (keratinocytes) and cultured how it is done to treat burns. Then, they were grafted into genetically modified mice so that they did not have an immune response to the transplant. Palacios believes that the fact that the trial is mixed (human cells in animals) will make it easier for people to try them, but, as usual, calls for calm. In them, the process would be to graft patches of cured skin.
The CRISPR technique is going to revolutionize the genetic edition for its precision, since it allows to choose where the genes that you want to add and where you want to cut are incorporated. Already at this time is especially useful for diseases with a single gene involved, as are many of the rare, said this weekend at a conference in Oviedo researchers César Nombela (currently rector of Menéndez Pelayo University) and Mario Fernández Fraga (Superior Council of Scientific Investigations). In its origin are the works of the Spanish Francisco Mójica. But there are still no approved treatments based on it, and there are many doubts about possible unethical uses, such as manipulating embryos to change aspects that are not curative, but aesthetic (hair color, for example) or other criteria (try to modify the features of an ethnic group).