AsianScientist (Oct. 7, 2013) – Saliva and tears are so integral to our day-to-day lives that most of us probably do not give a second thought to how our bodies make them. The glands responsible for doing so, however, can malfunction in many people for a variety of reasons.
The salivary gland can be affected by radiation therapy for head and neck cancer, resulting in various oral health problems such as microbial infection and difficulty in chewing and swallowing.
Lacrimal (tear) gland impairment may be caused by dry environments, refractive surgery, or the use of contact lenses, and can lead to significant visual impairment and discomfort. Dysfunction of both glands can also be caused by Sjögren’s syndrome, an autoimmune disease in which immune cells attack and destroy exocrine glands.
Artificial saliva or tear solutions and drugs that stimulate gland function can be used to treat these conditions, but these usually offer only temporary relief. Ideally, researchers would like to be able to permanently restore gland function through the use of stem cell-based regenerative techniques.
Now, a team of researchers from the Tokyo University of Science in Japan has bioengineered salivary and lacrimal glands and transplanted them successfully into mice. Their studies are reported in two back-to-back publications in the journal Nature Communications.
Starting with single cells derived from mouse embryos, the scientists were able to culture salivary and lacrimal gland precursors, or ‘organ germs,’ in a dish. When transplanted into mice, these organ germs developed into mature glands, which formed connections with the ducts and nervous system of the animals.
The team went on to show that the bioengineered glands were fully functional, churning out saliva and tears in response to various stimuli. The protein and lipid profiles of these secretions were also very similar to those of normal saliva and tears.
“In our study, we have provided a proof-of-concept for bioengineered secretory organ replacement as a organ regenerative therapy,” said Prof. Takashi Tsuji, who led the study.
Although mouse salivary and lacrimal glands are very similar to their human counterparts, several problems must be solved before the use of bioengineered secretory glands becomes feasible in humans. These include identifying suitable stem cell sources from patients and investigating methods to successfully engraft organ germs into recipients, said Prof. Tsuji.
In addition, although autoimmune diseases such as Sjögren’s syndrome are a major cause of secretory gland disorders, the specific antigens that trigger the damaging autoimmune response are unknown and remain an important area of research.
“The identification of the specific antigens will enable the bioengineered secretory gland to be regenerated using cells that suppress the gene expression of that antigen, contributing to the establishment of a radical treatment for dry mouth or dry eye due to autoimmune diseases,” said Prof. Tsuji.
The articles can be found at:
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Source: NPG; Photo: Creative Donkey/Flickr/CC.
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