Lacrimal and salivary glands from stem cells
Scientists at the University of Tokyo, working under the guidance of Professor Takashi Tsuji, demonstrated in experiments on mice the possibility of treating diseases of the lacrimal and salivary glands by transplanting embryos of these organs grown in laboratory conditions.
In their work, the authors used mouse models of diseases such as xerostomia and xerophthalmia, characterized by insufficient saliva and tears, respectively.
Xerostomia (dry mouth disease) often develops after radiotherapy of malignant tumors in the head area. It can lead to various problems with the condition of the oral cavity, including tooth decay, bacterial infections and swallowing disorders.
Xerophthalmia (dry eye disease) can develop as a result of defects in the lacrimal glands, and under the influence of external factors, including prolonged computer work and exposure to sunlight and tobacco smoke. Over the age of 50, the cause of the disease is most often an age-related decrease in the synthesis of fats in the body. Symptoms of the disease include pain and discomfort in the eyes, and prolonged course can lead to damage to the retina and blindness.
Existing methods of treatment of these diseases can only temporarily stimulate the secretory function of the glands, without completely eliminating the problem.
To create the rudiments of the submandibular salivary gland, as well as the lacrimal and garderian glands (the ocular gland in terrestrial, with the exception of primates and humans, and secondary aquatic vertebrates), researchers used epithelial and mesenchymal stem cells isolated from the salivary, lacrimal and garderian glands of mouse embryos. According to a technique they had previously developed, the scientists injected these cells into a collagen drop. In order for the interaction of the two types of cells to lead to the formation of ducts, the finest biodegradable polyglycolic acid filaments were introduced into the resulting structures in a certain way. The resulting rudiments of the glands were incubated under special conditions for three days.
With subsequent transplantation to animals, the resulting structures matured into full-fledged glands. Under the influence of pilocarpine, a drug used to treat dry mouth syndrome, as well as citric acid, the formed salivary glands secreted saliva. Moreover, the transplantation provided protection of the oral cavity of the animals from infections and restored swallowing function.
The lacrimal and gardera glands formed from the transplanted rudiments were also fully functional. In response to nervous stimulation of the eye, they secreted tears that effectively protected the cornea.
Top left: normal eye; top right: eye with damaged lacrimal gland; bottom left: eye with transplanted bioengineered lacrimal gland; bottom right: eye with transplanted bioengineered guard gland.
According to the researchers, the next stage of the work will be testing the method in clinical conditions, but before that, several problems have yet to be solved, including the selection of the optimal source of cells.
Articles by Miho Ogawa et al. Functional salivary gland regeneration by transplantation of a bioengineered organ germ and Masatoshi Hirayama et al. Functional lacrimal gland regeneration by transplantation of a bioengineered organ germ is published in the journal Nature Communications.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru according to Medical News Today: Scientists regenerate fully functional tear and saliva glands.
10.10.2013