Application of Stem Cells for Salivary Glands Regeneration
Date Issued
2010
Date
2010
Author(s)
Lin, Chia-Yung
Abstract
Background: There are still no effective solutions for atrophic salivary glands caused by autoimmune disease or radiation therapies for cancers. Hyposalivation results in severe dental problems reducing patients’ long-term life quality. Recent reports demonstrated that bone marrow stem cells have a great potential for transdifferentiating into different cells. We hypothesized that bone marrow stem cells can be transdifferentiated into salivary acinar cells for glands regeneration.
The purposes of this study were as follows: (1) to investigate the potentials of bone marrow stem cells transdifferentiating into salivary acinar cells (2) to investigate the effects of cell therapy for glands regeneration (3) to observe long term distributions of bone marrow stem cells transplanted into salivary glands (4) to discover the whole genome change of bone marrow stem cell transdifferentiated into salivary acinar cells.
Methods: bone marrow stem cells were acquired from 4-week-old rats and cocultured with submandibular glands acinar cells. Indirect coculture was preceded by culture inserts to separate these 2 kinds of cells. Bone marrow stem cells were on lower wells and acinar cells were on upper inserts; media could help signal compunctions through 0.4μm insert-membrane pores. Direct coculture was preceded by labeling bone marrow stem cells with DiI or Rhodamine-conjugated nanoparticles for cell-tracking. Immunocytochemical stains were performed to examine the changes after coculture. Next, mouse bone marrow stem cells were labeled with cationic lipid-coated ultra small superparamagnetic iron oxide nanoparticles and direct cocultured with acinar cells to obtain labeled acinar-like cells; both bone marrow stem cells and acinar-like cells were examined their therapeutic effects in the animal study. Total 140 severe combined immune deficiency mice were divided into 4 groups: (1) normal salivary glands mice, (2) mice received irradiation around their head-and-neck areas to cause atrophic glands (3) mice received irradiation and intra-gland transplantation with labeled bone marrow stem cells or (4) labeled acinar-like cells. Evaluations of glands functions were performed in all groups after cell therapy. Besides, distributions of bone marrow stem cells transplanted into glands were explored by specific designed equipments for in-vivo observation with the multiphoton laser fluorescence microscopy. The observation also assisted in examining transdifferentiation of bone marrow stem cells. Finally, microarray analyses were performed to examine the whole genome change of transdifferentiated bone marrow stem cells.
Results: After coculture, bone marrow stem cells were transdifferentiated into acinar-like cells with expressions of α-amylase protein, gene, and starch- digestion function. The animal study showed that damaged salivary glands with reduction in saliva production, body weight loss and gland weight loss due to irradiation can be rescued by cell therapy. For recovery of saliva production, cell therapy with acinar-like cells was significantly better than those with bone marrow stem cells. Transdifferentiation into acinar-like cells in-vivo was also noted by immunocytochemical staining. Besides, we designed specific equipments for in-vivo observation. By multiphoton laser fluorescence microscopy, distributions of transplanted cells could be observed directly. We also found that gene expressions of bone marrow stem cells related with mesenchymal characteristics were down regulated after coculture. In contrast, genes related with acinar cells such as water channels, sodium/potassium ions channels were unregulated.
Conclusion: This study is the first report demonstrating that bone marrow stem cells originated from the mesoderm are capable of transdifferentiating into acinar-like cells in-vitro and in-vivo. Acinar-like cells derived from bone marrow stem cells showed similarities from gene level to true function as salivary acinar cells originated from the ectoderm. Microarray analyses also confirmed this transdifferentiation. From animal study, acinar-like cells have better therapeutic effects in salivary glands regeneration. This study was also the first report for in-vivo observation of mice salivary glands with cell tracking of transplanted bone marrow stem cells.
Subjects
bone marrow stem cells
acinar-like cells
coculture
cell transdifferentiation
nanoparticles
multiphoton laser fluorescence microscopy
microarray analysis
hyposalivation
salivary glands regeneration
SDGs
Type
thesis
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