Supernatant of activated platelet-rich plasma rejuvenated aging-induced hyposalivation in mouse.

Hyposalivation is a common complaint among the elderly, but no established treatment prevents age-induced hyposalivation. 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. The platelets were separated from the blood of male SD rats (220 ± 20 g). saPRP was manufactured by removing the fibrin clot after activating platelet with calcium ionophore 10 µM (A23187). The total protein and TGF-ß1 levels were significantly higher in saPRP than in PRP. Human salivary gland epithelial cell(hSGEC) was 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 significantly reduced in 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 cell in 22 M + saPRP group. The decrease of senescence, apoptosis, and inflammation observed by western blot in 22 M + saPRP group. The saPRP induced the proliferation of hSGECs, leading to a significant decrease in cellular senescence via decrease inflammation and apoptosis, in vitro. Moreover, the acini cells of the salivary gland were regenerated, and the salivary function increased in aged mice. These results showed that saPRP could be a treatment agent against aging-induced SG dysfunction.

Adiponectin is associated with inflammaging and age-related salivary gland lipid accumulation.

Dry mouth is frequently observed in the elderly, and enhanced lipid accumulation plays a critical role in cellular senescence in the salivary gland (SG). We investigated the mechanisms that mediate lipogenesis-associated SG senescence. Adult (28.6 ± 6.6 y.o. and 43.3 ± 1.5 y.o.) and aged (82.0 ± 4.3 y.o. and 88.0 ± 4.3 y.o.) human parotid and submandibular glands were compared with respect to histologic findings, 8-OHdG (8-hydroxy 2 deoxyguanosine) expression patterns, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) and SA-ß-gal (senescence-associated ß-galactosidase) assay results. Also, microarray analysis was performed on RNA extracted from adult and aged SG to identify DEGs (differentially expressed genes). The effects of silencing ADIPOQ (Adiponectin) were evaluated by quantifying cell proliferation, immunohistochemical staining for cellular senescence and inflammation-associated proteins, SA-ß-gal assays, RT-PCR, and western blot. Histological findings demonstrated the presence of more lipocytes, chronic inflammation, fibrosis, and lymphocytic infiltration in old SG. In addition, old tissues demonstrated higher expressions of SA-ß-gal, more apoptotic cells in TUNEL assays, and higher oxidative stress by 8-OHdG immunostaining. Microarray analysis showed lipogenesis was significantly upregulated in old tissues. Silencing of ADIPOQ (a lipogenesis-related gene) reduced inflammation and SA-ß-gal levels and increased cell proliferation and the expressions of amylase and aquaporin 5 in human SG epithelial cells. The study shows ADIPOQ is a potential target molecule for the modulation of lipogenesis associated with SG senescence.

Cell-derived vesicles from adipose-derived mesenchymal stem cells ameliorate irradiation-induced salivary gland cell damage.

Introduction: Salivary gland (SG) damage is commonly caused by aging, irradiation, and some medications, and currently, no damage modifying agent is available. However, cell therapy based on mesenchymal stem cells (MSCs) has been proposed as a therapeutic modality for irradiated SGs. Therefore, we administered cell-derived vesicles (CDVs) of adipose-derived mesenchymal stem cells (ADMSCs) to irradiated SG cells to investigate their radioprotective effects in vitro. Methods: The artificial CDVs were obtained from ADMSC by tangential flow filtration (TFF) purification and ultracentrifugation. Cultured human SG epithelial cells were exposed to 2, 5 or 15 Gy of 4 MV X-rays produced by a linear accelerator. The effects of ADMSC-CDVs on SG epithelial cells damaged by irradiation were tested by proliferation activity, transepithelial electrical resistance (TEER), and amylase activity. Results: Exposure to penetrating radiation inhibited the proliferation of SG epithelial cells, but the radiation intensity required to reduce the proliferation of human submandibular gland epithelial cells (hSMGECs) was greater than required for other SG cells. ADMSC-CDVs restored the proliferative ability of SG epithelial cells reduced by irradiation, and the proliferation capacities of irradiated human parotid gland epithelial cells (hPGECs) and human sublingual gland epithelial cells (hSLGECs) were increased by administering ADMSC-CDVs to non-irradiated SG epithelial cells. Furthermore, amylase activity in irradiated hPGECs, hSMGECs, and hSLGECs was lower than in non-irradiated controls. However, amylase ability was restored in all by ADMSC-CDV treatment. Also, TEER was diminished by irradiation in hPGECs, hSMGECs, and hSLGECs and restored by ADMSC-CDV administration. Conclusion: Overall, our findings demonstrate that ADMSC-CDVs have potent radioprotective effects on irradiated SG cells.

Platelet-rich plasma loaded nerve guidance conduit as implantable biocompatible materials for recurrent laryngeal nerve regeneration.

Vocal cord paralysis caused by recurrent laryngeal nerve (RLN) injury during thyroidectomy results in hoarseness, aspiration, and dyspnea. We evaluated the usefulness of nerve guidance conduits (NGCs) constructed from an asymmetric polycaprolactone (PCL)/Pluronic F127 porous membrane and filled with platelet-rich plasma (PRP) for functional RLN regeneration. We evaluated the proliferation and migration of Schwann cells (SCs) after PRP treatment in vitro. For the in vivo study, rabbits were divided into a non-loaded NGC group and a PRP-loaded NGC group. The left RLNs were resected and interposed with the NGCs. Functional and histological examinations of the vocal cords were performed. SC proliferation and migration increased in a PRP dose-dependent manner, with the PRP increasing the levels of neurotrophic factors, myelin-associated glycoprotein, and ERK. In vivo, the PRP group showed significantly better vocal cord mobility and less vocalis muscle atrophy than the non-loaded NGC group. Histologically, the ingrowth of nerve endings occurred more rapidly in the PRP group, and acetylcholinesterase, neurofilament, and S-100 expression in neural endings were significantly higher in the PRP group. Furthermore, transmission electron microscopy showed that myelinated axons were more tightly packed in the PRP group. This study shows that PRP-loaded NGCs provide a favorable environment for neural regeneration and suggests that this technique has therapeutic potential for promoting RLN recovery.

Intralesional platelet-rich plasma injection promotes tongue regeneration following partial glossectomy in a murine model.

BACKGROUND: We examined the regenerative efficacy of the activated platelet-rich plasma (PRP) concentrate administered by local injection in an animal model mimicking partial glossectomy for tongue cancer. METHODS: Four-week-old mice were randomized to four groups; (1) a treatment-naïve control group, (2) a PRP group, (3) a hemiglossectomy group, and (4) a hemiglossectomy + PRP group. The activated PRP concentrate was injected into the deep layer of resected surfaces of mouse tongues immediately after excision, and tongue widths and lengths were measured on postoperative days (POD) 5 and 12. Gross tongue morphologies and microscopic findings were investigated. Inflammation and fibrous tissue areas were also measured, and immunohistochemical analysis was performed for c-kit, neurofilament, and S-100. RESULTS: The activated PRP concentrate reduced wound scar contracture, promoted wound healing, and reduced inflammation and wound fibrosis. On POD 12, histologic findings in the hemiglossectomy + PRP group were similar to those in the normal control group, and the intensity of stem cell factor receptor c-kit expression was also significantly greater in the PRP group than in the hemiglossectomy group on POD 12. Immunohistochemical staining revealed S100 and neurofilament expressions in the hemiglossectomy + PRP group were significantly more intense than in the hemiglossectomy group. CONCLUSION: Intralesional activated PRP concentrate injection has potential use for tongue regeneration, wound healing, and neural regeneration with minimal scarring after partial glossectomy.

Keratinocyte Growth Factor-1 Protects Radioiodine-Induced Salivary Gland Dysfunction in Mice.

BACKGROUND: Most patients with thyroid cancer suffer from salivary gland (SG) dysfunctions after radioiodine (RI) therapy. We investigated the effects of keratinocyte growth factor (KGF)-1 on RI-induced SG dysfunction in an animal model. METHODS: Six C57BL/6 mice were assigned to each of the following groups: treatment naïve control group, RI group, and RI+KGF-1 group. Body and SG weights, salivary flow rates, salivary lag times and changes in 99mTc pertechnetate uptake and excretion were measured, and histologic changes were noted. Amylase activities and epidermal growth factor (EGF) concentrations in saliva were also measured. In addition, TUNEL assays were performed and apoptosis-related protein expressions were assessed. RESULTS: RI-induced reductions in salivary flow rates and increases in salivary lag times observed in the RI group were not observed in RI+KGF-1 group. Mice in RI group had higher HIF1a levels than controls, but HIF1a levels in RI+KGF-1 group were similar to those in control group. Furthermore, mice in RI+KGF-1 group had more mucin stained acini and decreased periductal fibrosis than mice in RI group, and tissue remodeling of many salivary epithelial cells (AQP5) and endothelial cells (CD31) were observed in RI+KGF-1 group. Amylase activity and expression in saliva were greater in RI+KGF-1 group than in RI group, and fewer apoptotic cells were observed in RI+KGF-1 group. Furthermore, BCLxl (anti-apoptotic) expression was higher, and Bax (pro-apoptotic) expression was lower in RI+KGF-1 group than in RI group. CONCLUSIONS: Local delivery of KGF-1 might prevent RI-induced SG damage by reducing apoptosis.

Effect of expanding nanocellulose sponge on nasal mucosal defects in an animal model.

Nanocellulose has emerged for a wide range of applications in biomedical engineering because of its water absorption capacity, appropriate elasticity. We investigated the hemostatic and regenerative abilities of an expanding polyvinyl alcohol (PVA)-nanocellulose sponge on nasal mucosal defects. A 3 mm-diameter nasal defect was made in experimental rabbits. Rabbits were divided into four groups with control, vaseline, PVA and PVA-nanocellulose packing groups. After the defect was created, bleeding times and amounts were monitored. Packing materials were removed on experimental day (ED) 2. On ED 3, 7 and 14, histological analysis and immunohistochemical study for neutrophils were performed. Inflammatory cells were counted and epithelial thicknesses were evaluated. Bleeding amounts and times in the vaseline packing group were smaller than in the PVA groups. PVA-nanocellulose group showed less neutrophils than in the other groups on ED 7. Average epithelium thickness in the PVA-nanocellulose group was significantly smaller than in the control group at ED 7, but at ED 14, there was no significant intergroup difference. PVA-nanocellulose group had a significant lower inflammatory cell count than the control group on ED 7. PVA-nanocellulose sponge applied to nasal mucosal defects can significantly enhance mucosal regeneration during early wound healing.

Does Salivary Function Decrease in Proportion to Radioiodine Dose?

OBJECTIVES: This study was conducted to investigate the dose-response characteristics of radioiodine on salivary glands and to investigate the mechanism responsible for radioiodine-induced salivary glands toxicity. METHODS: Twenty-four mice were divided into six groups: 0, 0.05, 0.10, 0.20, 0.40, and 0.80 mCi/20 g mouse, administered orally. Mortalities were noted 12 months after radioiodine administration. Body weights, gland weights, salivary lag times, flow rates, and changes in 99m Tc pertechnetate were recorded. Histopathological changes and mRNA expressions were also evaluated, and immunohistochemical analysis and apoptotic assays were performed. RESULTS: Survival rates, body weights, gland weights, and flow rates decreased, and lag times increased on increasing radioiodine dose. Animals administered radioiodine showed acinar atrophy, striated duct dilations, and lymphocytic infiltration in glands and irregular destruction of epithelial surfaces of tongue. The uptake and excretion of 99m Tc pertechnetate were impaired by radioiodine. Immunohistochemical analysis showed that numbers of salivary epithelial, myoepithelial, and endothelial cells decreased and that numbers of ductal cells increased with radioiodine dose. Oxidative stress biomarker levels increased; reactive oxygen species scavenger levels decreased; and numbers of apoptotic cells increased in animals exposed to higher radioiodine doses. CONCLUSION: These dose-related, long-term effects on salivary gland should be taken into account when determining radioiodine doses. LEVEL OF EVIDENCE: NA Laryngoscope, 130:2173-2178, 2020.

Adipose-derived mesenchymal stem cells regenerate radioiodine-induced salivary gland damage in a murine model.

After radioiodine (RI) therapy, patients with thyroid cancer frequently suffer from painful salivary gland (SG) swelling, xerostomia, taste alterations, and oral infections. This study was aimed to determine whether adipose-derived mesenchymal stem cells (AdMSCs) might restore RI-induced SG dysfunction in a murine model. Forty -five mice were divided into three groups; a PBS sham group, a RI+ PBS sham group (0.01 mCi/g mouse, orally), and an RI+AdMSCs (1 × 105 cells/150 uL, intraglandular injection on experimental day 28) treated group. At 16 weeks after RI treatment, body weights, SG weight, salivary flow rates (SFRs), and salivary lag times were measured. Morphologic and histologic examinations and immunohistochemistry (IHC) were performed and the activities of amylase and EGF in saliva were also measured. Changes in salivary 99mTc pertechnetate excretion were followed by SPECT and TUNEL assays were performed. The body and SG weights were similar in the AdMSCs and sham groups. Hematoxylin and eosin staining revealed the AdMSCs group had more mucin-containing acini than the RI group. Furthermore, AdMSCs treatment resulted in tissue remodeling and elevated expressions of epithelial (AQP5) and endothelial (CD31) markers, and increased SFRs. The activities of amylase and EGF were higher in the AdMSCs group than in the RI treated group. 99mTc pertechnetate excretions were similar in the AdMSCs and sham group. Also, TUNEL positive apoptotic cell numbers were less in the AdMSCs group than in the RI group. Local delivery of AdMSCs might regenerate SG damage induced by RI.

Fucoidan attenuates radioiodine-induced salivary gland dysfunction in mice.

BACKGROUND: Radioiodine (RI) treatments can destroy the cellular components of salivary glands (SG) and disrupt their function. This study investigated whether fucoidan could attenuate radioiodine-induced SG dysfunction in a mouse model. METHODS: Female C57BL/6 mice (n = 36) were classified into three groups; i) a normal (control) group, ii) an RI-treated group (0.2 mCi/20 g mouse, administered orally), and iii) a fucoidan and RI-treated group. Mice in each group were classified into three subgroups and sacrificed at 2, 4, and 12 weeks after RI treatment. The measurements of salivary flow rates and lag times and histomorphologic examinations were performed, and apoptotic assays were conducted. Changes in salivary 99mTechnetium (Tc)-pertechnetate parameters using single-photon emission computed tomography were followed. RESULTS: Salivary flow rates and lag times in the fucoidan group were improved compared to the RI-treated group. Histologic examinations of SGs in the fucoidan group showed mucin-rich parenchymal areas and reduced periductal fibrosis as compared to the RI-treated group. Moreover, compared with the RI-treated group, fucoidan-treated groups showed evidence of cytoprotection, with a greater number of salivary epithelial cells and myoepithelial cells being observed. Fewer apoptotic cells were observed in the fucoidan group as compared to the RI group. The extent of 99mTc pertechnetate excretion in the fucoidan group was similar to that of the control group. CONCLUSION: Our results demonstrate that fucoidan administration before RI treatment could attenuate RI-induced SG damage and provides a possible candidate for preventing SG damage induced by RI.

Protective effects of curcumin on radioiodine-induced salivary gland dysfunction in mice.

Radioiodine (RI) treatment is widely used in patients with differentiated thyroid cancer. However, RI exposure often induces salivary gland (SG) dysfunction. In this study, we investigated the effect of curcumin on RI-induced SG dysfunction in mice. Mice were assigned to one of four groups (n = 6 per group) as follows: normal control, RI only, RI + curcumin, and RI + amifostine group. Salivary flow rate, lag time, and changes in 99m Tc (technetium)-pertechnetate uptake and excretion were measured, and changes in SG morphology and histology were analysed. Salivary epidermal growth factor content, amylase, and superoxide dismutase (SOD) activities were also measured. A terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was performed to assess SG apoptosis, and the expression of apoptosis-related protein was determined by western blotting. The reduced salivary flow rate and prolonged lag time in the RI group was restored by treatment with curcumin or amifostine. In the histological analysis, compared with the RI group, RI + curcumin and RI + amifostine groups had more mucin-rich acini and less periductal fibrosis. Compared with the RI group, RI + curcumin and RI + amifostine groups showed evidence of tissue remodelling, with a greater number of salivary epithelial cells (AQP-5-positive), SG ductal cells (CK18-positive), endothelial cells (CD31-positive), and myoepithelial cells (α-SMA-positive). RI + curcumin and RI + amifostine groups alleviated RI-induced cell death, demonstrating antiapoptotic effect, compared with the RI group. Both SOD activity and the protein expression levels of SOD2 were higher in the RI + curcumin and RI + amifostine groups than in the RI group. Our results demonstrate that curcumin ameliorates RI-induced SG dysfunction in mice.