Platelet Rich Plasma Treatment Rescues Damaged Salivary Gland Function in Aged Mice
Dysfunction of the salivary gland is an underappreciated and unpleasant age-related condition. Researchers here demonstrate that injection of platelet rich plasma into the salivary gland can rescue function in old mice by promoting regrowth of lost cells, reducing inflammation, and reducing the burden of cellular senescence in this tissue. As noted in the paper, platelet rich plasma is fairly widely used in the regenerative medicine industry, and this sort of result in an animal model is one of the reasons why this is the case.
Saliva, synthesized and secreted by the salivary glands (SGs), plays an essential role in the oral cavity by maintaining oral homeostasis, protecting against infection, and promoting digestion. A dysfunction of the SG leads to xerostomia or dry mouth, sialadenitis or salivary gland inflammation, worsening of dental caries, and periodontal diseases. Furthermore, xerostomia reduces overall health or the quality of patient's life. Temporal xerostomia is caused by acute infection or dehydration. On the other hand, permanent xerostomia is caused by autoimmune inflammatory diseases such as Sjogren syndrome, radiation therapy in head and neck cancer patients, xerogenic medication, or aging.
Platelet derivatives such as platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and plasma rich in growth factor (PRGF), are used widely in different areas of regenerative medicine to enhance the wound healing processes. This study examined whether the local injection of the supernatant of activated PRP (saPRP) into the salivary gland (SG) could help prevent aging-induced SG dysfunction and explored the mechanisms responsible for the protective effects on the SG hypofunction.
Human salivary gland epithelial cells (hSGEC) were treated with saPRP or PRP after senescence through irradiation. The significant proliferation of hSGEC was observed in saPRP treated group compared to irradiation only group and irradiation + PRP group. Cellular senescence, apoptosis, and inflammation were significantly reduced in the saPRP group.
The SG function and structural tissue remodeling by the saPRP were investigated with naturally aged mice. The mice were divided into three groups: 3 months old (3 M), 22 months old (22 M), and 22 months old treated with saPRP (22 M + saPRP). Salivary flow rate and lag time were significantly improved in 22 M + saPRP group compared to 22 M group. The histologic examinations showed the significant proliferation of acinar cells in the SG of the 22 M + saPRP group. A decrease of senescence, apoptosis, and inflammation was observed by western blot in the 22 M + saPRP group.
Too bad the authors of this study did not add a group of mice injected with saline or saline+albumin. There are scientific papers published in the public domain in which the therapeutic effect of blood plasma injection was comparable to saline+albumin injection
It's the mitochondria!