Researchers make progress in growing another tissue type from cells:
[Researchers have] created precursors to salivary and lacrimal glands that, when transplanted into mice, successfully connected to the host ducts and nervous system. Once connected, these lab-grown secretory glands helped to restore the production of saliva and tears in animals from which healthy salivary or lacrimal glands had previously been excised.
To create the secretory glands, [the researchers] built on previous work that used a bioengineering technique they developed to reconstitute organ germs from teeth and hair follicles via a 3-D cell processing method. First, they created the glandular precursors - or "germs" - in vitro using single epithelial and mesenchymal cells isolated from embryonic glands. After three days in organ culture, the bioengineered glands had undergone branching morphogenesis, followed by stalk elongation and cleft formation - three tell-tale signs of organogenesis. By that time, the researchers also observed an accumulation of saliva in the ducts of the bioengineered salivary gland germs.
[The researchers] next engrafted these secretory gland germs in mice - from which healthy salivary or lacrimal glands had been removed - using a nylon thread-guided, interepithelial tissue-connecting plastic method it published [last year]. Not only did the precursor secretory glands innervate, but in response to stimulation by the nervous system, they began to secrete saliva and tears, moistening dry mouths and eyes in the animal models.