Glucagon-like peptide-1 analogue liraglutide facilitates wound healing by activating PI3K/Akt pathway in keratinocytes

GLP-1 Agonists: A Practical Overview for Plastic and Reconstructive Surgeons

BACKGROUND

Glucagon-like peptide-1 (GLP-1) agonists, such as exenatide, liraglutide, dulaglutide, semaglutide, and tirzepatide, effectively manage type 2 diabetes by promoting insulin release, suppressing glucagon secretion, and enhancing glucose metabolism. They also aid weight reduction and cardiovascular health, potentially broadening their therapeutic scope. In plastic surgery, they hold promise for perioperative weight management and glycemic control, potentially impacting surgical outcomes.

METHODS

A comprehensive review was conducted to assess GLP-1 agonists' utilization in plastic surgery. We analyzed relevant studies, meta-analyses, and trials to evaluate their benefits and limitations across surgical contexts, focusing on weight reduction, glycemic control, cardiovascular risk factors, and potential complications.

RESULTS

Studies demonstrate GLP-1 agonists' versatility, spanning weight management, cardiovascular health, neurological disorders, and metabolic dysfunction-associated liver diseases. Comparative analyses highlight variations in glycemic control, weight loss, and cardiometabolic risk. Meta-analyses reveal significant reductions in hemoglobin A1C levels, especially with high-dose semaglutide (2 mg) and tirzepatide (15 mg). However, increased dosing may lead to gastrointestinal side effects and serious complications like pancreatitis and bowel obstruction. Notably, GLP-1 agonists' efficacy in weight reduction and glycemic control may impact perioperative management in plastic surgery, potentially expanding surgical candidacy for procedures like autologous flap-based breast reconstruction and influencing outcomes related to lymphedema. Concerns persist regarding venous thromboembolism and delayed gastric emptying, necessitating further investigation into bleeding and aspiration risk with anesthesia.

CONCLUSIONS

GLP-1 agonists offer advantages in perioperative weight management and glycemic control in plastic surgery patients. They may broaden surgical candidacy and mitigate lymphedema risk but require careful consideration of complications, particularly perioperative aspiration risk. Future research should focus on their specific impacts on surgical outcomes to optimize their integration into perioperative protocols effectively. Despite challenges, GLP-1 agonists promise to enhance surgical outcomes and patient care in plastic surgery.

Incretin-based therapy and the risk of diabetic foot ulcers and related events

AIM

To investigate the effect of dipeptidyl peptidase-4 inhibitors (DPP4-Is) and glucagon-like peptide-1 receptor agonists (GLP1-RAs) on diabetic foot ulcer (DFU) and DFU-related outcomes (lower limb amputation [LLA], DFU-related hospitalization and mortality).

METHODS

We performed a cohort study with data from the Clinical Practice Research Datalink Aurum database with linkage to hospital data. We included people with type 2 diabetes starting treatment with metformin. Then we propensity score matched new users of DPP4-Is and sulphonylureas (N = 98 770), and new users of GLP1-RAs and insulin (N = 25 422). Cox proportional hazards models estimated the hazard ratios (HRs) for the outcomes.

RESULTS

We observed a lower risk of DFU with both DPP4-I use versus sulphonylurea use (HR 0.88, 95% confidence interval [CI]: 0.79-0.97) and GLP1-RA use versus insulin use (HR 0.44, 95% CI: 0.32-0.60) for short-term exposure (≤ 400 days) and HR 0.74 (95% CI: 0.60-0.92) for long-term exposure (>400 days). Furthermore, the risks of hospitalization and mortality were lower with both DPP4-I use and GLP1-RA use. The risk of LLA was lower with GLP1-RA use. The results remained consistent across several sensitivity analyses.

CONCLUSIONS

Incretin-based therapy was associated with a lower risk of DFU and DFU-related outcomes. This suggests benefits for the use of this treatment in people at risk of DFU.

G Protein-Coupled Receptors in Skin Aging

Skin aging is a complex biological process affected by a plethora of intrinsic and extrinsic factors that alter cutaneous functions through the modulations of signaling pathways and responses. Expressed in various cell types and skin tissue layers, G protein-coupled receptors (GPCRs) play a vital role in regulating skin aging. We have cataloged 156 GPCRs expressed in the skin and reviewed their roles in skin aging, such as pigmentation, loss of elasticity, wrinkles, rough texture, and aging-associated skin disorders. By exploring the GPCRs found in the skin, it may be possible to develop new treatment regimens for aging-associated skin conditions using GPCR ligands.

Morroniside promotes skin wound re-epithelialization by facilitating epidermal stem cell proliferation through GLP-1R-mediated upregulation of β-catenin expression

Epidermal stem cells (EpSCs) play a vital role in skin wound healing through re-epithelialization. Identifying chemicals that can promote EpSC proliferation is helpful for treating skin wounds. This study investigates the effect of morroniside on cutaneous wound healing in mice and explores the underlying mechanisms. Application of 10‒50 μg/mL of morroniside to the skin wound promotes wound healing in mice. In vitro studies demonstrate that morroniside stimulates the proliferation of mouse and human EpSCs in a time- and dose-dependent manner. Mechanistic studies reveal that morroniside promotes the proliferation of EpSCs by facilitating the cell cycle transition from the G1 to S phase. Morroniside increases the expression of β-catenin via the glucagon-like peptide-1 receptor (GLP-1R)-mediated PKA, PKA/PI3K/AKT and PKA/ERK signaling pathways, resulting in an increase in cyclin D1 and cyclin E1 expression, either directly or by upregulating c-Myc expression. This process ultimately leads to EpSC proliferation. Administration of morroniside to mouse skin wounds increases the phosphorylation of AKT and ERK, the expressions of β-catenin, c-Myc, cyclin D1, and cyclin E1, as well as the proliferation of EpSCs, in periwound skin tissue, and accelerates wound re-epithelialization. These effects of morroniside are mediated by the GLP-1R. Overall, these results indicate that morroniside promotes skin wound healing by stimulating the proliferation of EpSCs via increasing β-catenin expression and subsequently upregulating c-Myc, cyclin D1, and cyclin E1 expressions through GLP-1R signaling pathways. Morroniside has clinical potential for treating skin wounds.

Glucagon like peptide-1 receptor agonists and the risk of skin cancer among patients with type 2 diabetes: Population-based cohort study

AIMS

The objective of this study was to determine whether the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) is associated with an increased risk of melanoma and nonmelanoma skin cancer, separately, compared with the use of sulfonylureas among patients with type 2 diabetes.

METHODS

Using the United Kingdom Clinical Practice Research Datalink (2007-2019), we assembled two new-user active comparator cohorts. In the first cohort assessing melanoma as the outcome, 11,786 new users of GLP-1 RAs were compared with 208,519 new users of sulfonylureas. In the second cohort assessing nonmelanoma skin cancer as the outcome, 11,774 new users of GLP-1 RAs were compared with 207,788 new users of sulfonylureas. Cox proportional hazards models weighted using propensity score fine stratification were fit to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of melanoma and nonmelanoma skin cancer, respectively.

RESULTS

Compared with sulfonylureas, GLP-1 RAs were not associated with an increased risk of either melanoma (42.6 vs. 43.9 per 100,000 person-years, respectively; HR 0.96, 95% CI 0.53-1.75) or nonmelanoma skin cancer (243.9 vs. 229.9 per 100,000 person-years, respectively; HR 1.03, 95% CI 0.80-1.33). There was no evidence of an association between cumulative duration of use with either melanoma or nonmelanoma skin cancer. Consistent results were observed in secondary and sensitivity analyses.

CONCLUSIONS

In this population-based cohort study, GLP-1 RAs were not associated with an increased risk of melanoma or nonmelanoma skin cancer, compared with sulfonylureas.

Practice Patterns and Perspectives of the Off-Label Use of GLP-1 Agonists for Cosmetic Weight Loss

BACKGROUND

The off-label use of glucagon-like peptide 1 (GLP-1) agonists for cosmetic weight loss has captured the interest of the public. However, there is a paucity of published data on their utilization, implications, and management, particularly in the plastic surgery community.

OBJECTIVES

This study aims to explore the current practice patterns of aesthetic plastic surgeons regarding the off-label implementation of GLP-1 agonists.

METHODS

A 35-question survey was sent to the 2600 members of The Aesthetic Society in July 2023. The survey collected physician demographics, practice settings, patient population demographics, and the use and management of GLP-1 agonists in their practice. No identifying variables were collected; all responses were anonymous.

RESULTS

A total of 368 respondents were included. A quarter of respondents (25.3%) prescribed or utilized GLP-1 agonists in their practice. Nearly a third (29.9%) reported personal use of the medication, of which 71 (70.3%) indicated it was for cosmetic weight loss. Many aspects of the current treatment, counseling, and follow-up practices were similar among prescribing plastic surgeons. However, there were discrepancies in screening, nutrition counseling, and perioperative management. The majority believed that GLP-1 agonists were effective for weight loss (68.9%), profitable for business (57.8%), and would recommend its implementation to other plastic surgeons (68.5%).

CONCLUSIONS

As leaders in the aesthetic field, it behooves plastic surgeons to take charge of shaping public opinion surrounding the growing off-label use of GLP-1 agonists for cosmetic weight loss. Plastic surgeons' leadership is imperative in establishing safe and ethical guidelines and protocols for proper screening, management, and patient care.

LEVEL OF EVIDENCE: 4

Recent Advances in Functional Wound Dressings

Significance: Nowadays, the wound dressing is no longer limited to its primary wound protection ability. Hydrogel, sponge-like material, three dimensional-printed mesh, and nanofiber-based dressings with incorporation of functional components, such as nanomaterials, growth factors, enzymes, antimicrobial agents, and electronics, are able to not only prevent/treat infection but also accelerate the wound healing and monitor the wound-healing status. Recent Advances: The advances in nanotechnologies and materials science have paved the way to incorporate various functional components into the dressings, which can facilitate wound healing and monitor different biological parameters in the wound area. In this review, we mainly focus on the discussion of recently developed functional wound dressings. Critical Issues: Understanding the structure and composition of wound dressings is important to correlate their functions with the outcome of wound management. Future Directions: "All-in-one" dressings that integrate multiple functions (e.g., monitoring, antimicrobial, pain relief, immune modulation, and regeneration) could be effective for wound repair and regeneration.

Glucagon-like Peptide-1 Treatment Reduces the Risk of Diabetes-Type 2 Related Amputations: A Cohort Study in Denmark

AIMS

To assess the impact of Glucagon-like peptide-1 (GLP-1) agonists on the risk of lower extremity amputations in patients with type 2 diabetes mellitus (DM2).

METHODS

We conducted a cohort study on 309,116 patients with DM2 using Danish National Register and Diabetes Database. We tracked the GLP-1 agonists over time along with the medication dose. Time-varying models are used to assess the risk of amputation for patients with/without GLP-1 treatment.

RESULTS

Patients on GLP-1 treatment experience a notable reduction in the risk of amputation compared to those without the treatment with a hazard ratio (HR) of 0.5, 95% CI [0.54-0.74], indicating a statistically significant difference (p < .005). This risk reduction was consistent across different age groups, but notably most pronounced among middle income patients. The findings were further validated by using time-varying Cox models, which considered the patient's comorbidity history.

CONCLUSIONS

Our analysis reveals compelling evidence of a reduced risk of amputation among patients receiving Liraglutide treatment compared to those without the treatment, even after adjusting for various socio-economic factors. However, further investigation is required to identify and account for any other potential confounding variables that may impact the outcome.

Review on Extraction, Modification, and Synthesis of Natural Peptides and Their Beneficial Effects on Skin

Peptides, functional nutrients with a size between those of large proteins and small amino acids, are easily absorbed by the human body. Therefore, they are seeing increasing use in clinical medicine and have revealed immunomodulatory and anti-inflammatory properties which could make them effective in healing skin wounds. This review sorted and summarized the relevant literature about peptides during the past decade. Recent works on the extraction, modification and synthesis of peptides were reviewed. Importantly, the unique beneficial effects of peptides on the skin were extensively explored, providing ideas for the development and innovation of peptides and laying a knowledge foundation for the clinical application of peptides.

GLP-1 receptor agonist as a modulator of innate immunity

Glucagon-like peptide-1 (GLP-1) is a 30-amino acid hormone secreted by L cells in the distal ileum, colon, and pancreatic α cells, which participates in blood sugar regulation by promoting insulin release, reducing glucagon levels, delaying gastric emptying, increasing satiety, and reducing appetite. GLP-1 specifically binds to the glucagon-like peptide-1 receptor (GLP-1R) in the body, directly stimulating the secretion of insulin by pancreatic β-cells, promoting proliferation and differentiation, and inhibiting cell apoptosis, thereby exerting a glycemic lowering effect. The glycemic regulating effect of GLP-1 and its analogues has been well studied in human and murine models in the circumstance of many diseases. Recent studies found that GLP-1 is able to modulate innate immune response in a number of inflammatory diseases. In the present review, we summarize the research progression of GLP-1 and its analogues in immunomodulation and related signal pathways.

Insulin activates LC-PUFA biosynthesis of hepatocytes by regulating the PI3K/Akt/mTOR/Srebp1 pathway in teleost Siganus canaliculatus

Insulin is well known an important metabolic regulator in glucose and lipid metabolism. It has been proved to activate long-chain (≥ C₂₀) polyunsaturated fatty acids (LC-PUFA) biosynthesis in mammals, but little is known about such a role in fish. To explore the effects and molecular mechanisms of insulin in fish LC-PUFA biosynthesis, we treated the rabbitfish S. canaliculatus hepatocyte line (SCHL) cells with 65 nM insulin for 12 h, and the results showed that the mRNA levels of genes encoding the key enzymes and transcription factor involved in rabbitfish LC-PUFA biosynthesis such as Δ6Δ5 fads2, elovl5 and srebp1, as well as those of PI3K pathway genes including pdk1, akt2 and mtor increased significantly. Moreover, SCHL cells treated with different PI3K/Akt pathway inhibitors (LY294002, Wortmannin, AKTi-1/2) alone or combined with insulin decreased the mRNA levels of PI3K/Akt/mTOR downstream signaling genes, including Δ6Δ5 fads2, Δ4 fads2, elovl5, elovl4 and srebp1. While PI3K/Akt agonists (740 Y-P, IGF-1, SC-79) had the opposite results. The results of fatty acid composition analysis of hepatocytes showed that insulin stimulation increased the Δ6Δ5 Fads2-dependent PUFA desaturation indexes, while Elovl5-dependent PUFA elongation indexes had upward trends, and consequently LC-PUFA contents increased. Taken together, these results indicated that insulin activated LC-PUFA biosynthesis probably through PI3K/Akt/mTOR/Srebp1 pathway in S. canaliculatus hepatocytes.

Antidiabetic effects of quercetin and liraglutide combination through modulation of TXNIP/IRS-1/PI3K pathway

The study was designed to assess the possible augmented antidiabetic effects of combining quercetin and liraglutide in a type 1 diabetes model, with emphasis on the contribution of hepatic thioredoxin interacting protein (TXNIP)/insulin receptor substrate 1 (IRS-1)/phosphatidyl inositol-3 kinase (PI3K) pathway. The wound-healing effects were also examined. Diabetes was induced by a single i.p STZ injection (55 mg/kg). Diabetic rats were treated with either quercetin (100 mg/kg/day, orally) or liraglutide (0.3 mg/kg/twice daily, S.C.) or their combination. Drugs were also applied topically on the wound. Blood glucose levels, serum albumin, total protein, total cholesterol and triglycerides were measured. Histopathological examination of the liver, pancreas and skin tissues was performed using haematoxylin and eosin staining. The hepatic malondialdehyde level was measured spectrophotometrically. Hepatic TXNIP and PI3K levels were measured by enzyme-linked immunsorbent assay (ELISA). Tissue expression of IRS-1 and phospho-IRS-1 (Ser 616) was assessed by immunohistochemistry. Quercetin, liraglutide and their combination effectively decreased blood glucose levels, improved lipid profile, upregulated albumin and total protein serum levels and reduced hepatic oxidative stress with the combination being most effective. Moreover, the combination group showed enhanced wound-healing effects and almost normalized hepatic and pancreatic histopathology. Quercetin and/or liraglutide significantly decreased TXNIP levels and serine phosphorylation of IRS-1 and increased PI3K levels compared to the diabetic untreated group. Interestingly, only the combination therapy normalized hepatic IRS-1 expression. The combination of quercetin and liraglutide showed enhanced antidiabetic effects, possibly through lowering hepatic TXNIP levels, with the resultant up-regulation of the IRS-1/PI3K pathway.

Resveratrol promotes skin wound healing by regulating the miR-212/CASP8 axis

The wound-healing process is a natural response to burn injury. Resveratrol (RES) may have potential as a therapy for wound healing, but how and whether RES regulates skin repair remains poorly understood. Human epidermal keratinocyte (HaCaT) cells were treated with lipopolysaccharide (LPS), and a mouse skin wound-healing model was established. Cell viability and apoptosis were analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide or flow cytometry. Cell proliferation was assessed by cell viability and colony-formation analyses. Cell migration was tested by wound-healing analysis. The microRNA-212 (miR-212) and caspase-8 (CASP8) levels were determined by quantitative reverse transcription polymerase chain reaction and western blotting. The correlation between miR-212 and CASP8 was analyzed by dual-luciferase reporter analysis. Skin wound healing in mice was assessed by measuring the wound area and gap after hematoxylin-eosin (HE) staining. RES reduced the LPS-induced reduction in viability and apoptosis in HaCaT cells. miR-212 expression was reduced by LPS and increased by exposure to RES. RES promoted cell proliferation and migration after LPS treatment by increasing miR-212 levels. CASP8 was a target of miR-212. CASP8 silencing promoted cell proliferation and migration, which was reversed by miR-212 knockdown in LPS-treated HaCaT cells. RES promoted skin wound healing in mice, which was reduced by miR-212 knockdown. Thus, RES facilitates cell proliferation and migration in LPS-treated HaCaT cells and promotes skin wound-healing in a mouse model by regulating the miR-212/CASP8 axis.

Therapeutic candidates for keloid scars identified by qualitative review of scratch assay research for wound healing

The scratch assay is an in vitro technique used to analyze cell migration, proliferation, and cell-to-cell interaction. In the assay, cells are grown to confluence and then ‘scratched’ with a sterile instrument. For the cells in the leading edge, the resulting polarity induces migration and proliferation in attempt to ‘heal’ the modeled wound. Keloid scars are known to have an accelerated wound closure phenotype in the scratch assay, representing an overactivation of wound healing. We performed a qualitative review of the recent literature searching for inhibitors of scratch assay activity that were already available in topical formulations under the hypothesis that such compounds may offer therapeutic potential in keloid treatment. Although several shortcomings in the scratch assay literature were identified, caffeine and allicin successfully inhibited the scratch assay closure and inflammatory abnormalities in the commercially available keloid fibroblast cell line. Caffeine and allicin also impacted ATP production in keloid cells, most notably with inhibition of non-mitochondrial oxygen consumption. The traditional Chinese medicine, shikonin, was also successful in inhibiting scratch closure but displayed less dramatic impacts on metabolism. Together, our results partially summarize the strengths and limitations of current scratch assay literature and suggest clinical assessment of the therapeutic potential for these identified compounds against keloid scars may be warranted.

The role of incretins and incretin-based drugs in autoimmune diseases

Incretin hormones, including glucagon-like peptide (GLP)-1, GLP-2 and glucose-dependent insulinotropic polypeptide (GIP), are gastrointestinal peptides secreted from enteroendocrine cells. These hormones play significant roles in many physiological processes via binding to G-protein coupled receptors (GPCRs) on different organs and tissues; one of them is the immunomodulatory effect on the immune system and its molecular components such as cytokines and chemokines. Anti-inflammatory effects of incretins and dependent molecules involving long-acting analogs and DPP4 inhibitors through regulation of T and B cell activation may attenuate autoimmune diseases caused by immune system disorders in mistakenly recognizing self as the foreign agent. In this review, we investigate incretin effects on the immune system response and the potential benefits of incretin-based therapy for treating autoimmune diseases.

Liraglutide modulates olfactory ensheathing cell migration with activation of ERK and alteration of the extracellular matrix

Transplantation of olfactory ensheathing cells (OECs) is a promising approach for repairing the injured nervous system that has been extensively trialed for nervous system repair. However, the method still needs improvement and optimization. One avenue of improving outcomes is to stimulate OEC migration into the injury site. Liraglutide is a glucagon-like peptide-1 receptor agonist used for management of diabetes and obesity. It has been shown to be neuroprotective and to promote cell migration, but whether it can stimulate glial cells remains unknown. In the current study, we investigated the effects of liraglutide on OEC migration and explored the involved mechanisms. We showed that liraglutide at low concentration (100 nM) overall promoted OEC migration over time. Liraglutide modulated the migratory behavior of OECs by reducing time in arrest, and promoted random rather than straight migration. Liraglutide also induced a morphological change of primary OECs towards a bipolar shape consistent with improved migration. We found that liraglutide activated extracellular signal-regulated kinase (ERK), which has key roles in cell migration; the timing of ERK activation correlated with stimulation of migration. Furthermore, liraglutide also modulated the extracellular matrix by upregulating laminin-1 and down-regulating collagen IV. In summary, we found that liraglutide can stimulate OEC migration and re-model the extracellular matrix to better promote cell migration, and possibly also to become more conducive for axonal regeneration. Thus, liraglutide may improve OEC transplantation outcomes.

Dedicator of Cytokinesis 5 Regulates Keratinocyte Function and Promotes Diabetic Wound Healing

Cutaneous wound healing is a fundamental biologic and coordinated process, and failure to maintain this process contributes to the dysfunction of tissue homeostasis, increasing the global burden of diabetic foot ulcerations. However, the factors that mediate this process are not fully understood. Here, we identify the pivotal role of dedicator of cytokinesis 5 (Dock5) in keratinocyte functions contributing to the process of skin wound healing. Specifically, Dock5 is highly upregulated during the proliferative phase of wound repair and is predominantly expressed in epidermal keratinocytes. It regulates keratinocyte adhesion, migration, and proliferation and influences the functions of extracellular matrix (ECM) deposition by facilitating the ubiquitination of transcription factor ZEB1 to activate laminin-332/integrin signaling. Genetic ablation of Dock5 in mice leads to attenuated reepithelialization and granulation tissue formation, and Dock5 overexpression-improved skin repair can be abrogated by LAMA3 knockdown. Importantly, Dock5 expression in the skin edge is reduced in patients and animal models of diabetes, further suggesting a direct correlation between its abundance and healing capability. The rescue of Dock5 expression in diabetic mice causes a significant improvement in reepithelialization, collagen deposition, ECM production, and granulation. Our study provides a potential therapeutic target for wound healing impairment during diabetes.

A Small-Sized Population of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Shows High Stemness Properties and Therapeutic Benefit

Mesenchymal stem cells (MSCs) represent a promising means to promote tissue regeneration. However, the heterogeneity of MSCs impedes their use for regenerative medicine. Further investigation of this phenotype is required to develop cell therapies with improved clinical efficacy. Here, a small-sized population of human umbilical cord blood-derived MSCs (UCB-MSCs) was isolated using a filter and centrifuge system to analyze its stem cell characteristics. Consequently, this population showed higher cell growth and lower senescence. Additionally, it exhibited diverse stem cell properties including differentiation, stemness, and adhesion, as compared to those of the population before isolation. Using cell surface protein array or sorting analysis, both EGFR and CD49f were identified as markers associated with the small-sized population. Accordingly, suppression of these surface proteins abolished the superior characteristics of this population. Moreover, compared to that with large or nonisolated populations, the small-sized population showed greater therapeutic efficacy by promoting the engraftment potential of infused cells and reducing lung damage in an emphysema mouse model. Therefore, the isolation of this small-sized population of UCB-MSCs could be a simple and effective way to enhance the efficacy of cell therapy.

Lactobacillus reuteri extracts promoted wound healing via PI3K/AKT/β-catenin/TGFβ1 pathway

BACKGROUND

The balance of oral microbiomes is crucial to maintain oral health. Microecological imbalance can impair the function of mesenchymal stem cells (MSCs) and lead to delay wound healing. Probiotics is a promising prevention approach for the treatment of oral inflammatory diseases caused by a bacterial infection. However, the effect of probiotics on oral MSCs and wound healing is unclear. In the present study, we used one type of probiotics Lactobacillus reuteri extracts to determine whether bacterial extracts could regulate the functions of gingiva MSCs (GMSCs) and promote wound healing.

METHODS

Lactobacillus reuteri was prepared with bacterial extracts using ultrasonic crushing apparatus. The effects of Lactobacillus reuteri extracts on GMSCs were tested using the cell scratch migration, alkaline phosphatase (ALP) activity, alizarin red staining, cell counting kit-8, real-time PCR, and western blot assays. To investigate the role of Lactobacillus reuteri extracts in the wound in mice, the wound position of bilateral mesial gingival of the maxillary first molar was established, the wound area with a size of 1 mm × 2 mm and the full thickness gingiva was removed. Mice with wound were randomly distributed to two groups: injection of 0.9% NaCl (NS group) or injection of 50 μg/ml bacterial extracts.

RESULTS

We discovered that 50 μg/ml Lactobacillus reuteri extracts increased the capacities of migration, expression of stem cell markers, osteogenic differentiation, and proliferation of GMSCs. In addition, local injection of 50 μg/ml bacterial extracts could promote wound-healing process in mice models. Mechanistically, we found that Lactobacillus reuteri extracts accelerated the process of wound healing via PI3K/AKT/β-catenin/TGFβ1 pathway.

CONCLUSIONS

These data showed that Lactobacillus reuteri extracts could activate the potentials of GMSCs, thus promote wound healing. Our discovery provided the insight of the underlying mechanism activating functions of MSCs and identified Lactobacillus reuteri extracts as a potential therapeutic strategy for accelerating oral wound and potential application in the future dental clinic.