Labial Stem Cell Extract Mitigates Injury to Irradiated Salivary Glands

Area of Science:

• Regenerative Medicine
• Stem Cell Biology
• Radiation Oncology

Background:

• Salivary gland hypofunction following ionizing radiation (IR) injury presents significant challenges for patients.
• Current stem cell therapies for salivary gland injury face hurdles including invasiveness and cell delivery.
• A less invasive, cell-free therapeutic approach is needed to mitigate IR-induced salivary gland damage.

Purpose of the Study:

• To develop a clinically feasible method for isolating and expanding human salivary gland stem cells.
• To create a cell-free extract (LSCE) from these stem cells for therapeutic use.
• To evaluate the efficacy of LSCE in treating IR-injured salivary glands in a preclinical model.

Main Methods:

• Human labial glands were biopsied to isolate and expand labial stem cells (LSCs) via explant culture.
• A cell-free extract (LSCE) was generated using freeze-thaw cycles and centrifugation.
• LSCE was intravenously administered to mice with IR-induced salivary gland injury, with saline as a control.

Main Results:

• Explant culture yielded millions of LSCs from small tissue samples, demonstrating efficient expansion.
• LSCE contained both angiogenic and anti-angiogenic factors, with some exhibiting neurotrophic properties.
• LSCE treatment significantly increased salivary flow rate and reduced saliva lag time in IR-injured mice compared to controls.
• Histological analysis revealed LSCE promoted recovery of acinar cells, blood vessels, and nerves in salivary glands.

Conclusions:

• A minimally invasive method for generating a potent cell-free salivary gland regenerative therapy (LSCE) from LSCs has been established.
• LSCE demonstrates significant potential to restore salivary gland function after radiation injury.
• This cell-free approach offers a promising clinical strategy for managing radiation-induced xerostomia.