Introduction and Objective: Oxidative stress and mitochondrial dysfunction play a pivotal role in the pathogenesis of diabetic neuropathy. We previously reported that hyperglycemia and glucose fluctuations induce mitochondrial dysfunction and cell death in immortalized adult mouse Schwann (IMS32) cells. Recently, the oral glucose-lowering drug imeglimin has been shown to attenuate ROS generation and improve mitochondrial function in hepatocytes. In addition, nicotinamide mononucleotide (NMN), a precursor of NAD+, has emerged as a key regulator of energy metabolism and cellular senescence. In this study, we investigated the effects of imeglimin and NMN on high glucose-induced mitochondrial dysfunction and cellular senescence in Schwann cells. Methods: IMS32 cells were cultured under either normal glucose (5.5 mM) or high glucose (25 mM). The levels of mitochondrial oxidative stress and intracellular NAD+ were measured. The protein expression levels of the longevity gene Sirt1 and the mitochondrial biogenesis-related factors PGC1α and TFAM were evaluated. Senescent cells were identified by senescence-associated β-galactosidase (SA-β-gal) staining. Results: Imeglimin and NMN suppressed high glucose-increases in mitochondrial oxidative stress. Imeglimin significantly increased intracellular NAD+ levels. Both agents restored the high glucose-induced downregulation of Sirt1, PGC1α, and TFAM expression and attenuated the increase in SA-β-gal-positive cells. Conclusion: These findings suggest that the accumulation of senescent Schwann cells may contribute to the development and progression of diabetic neuropathy. Imeglimin and NMN improved high glucose-induced mitochondrial dysfunction and suppressed cellular senescence in Schwann cells, suggesting its potential therapeutic benefits for diabetic neuropathy. Disclosure A. Kato: None. W. Nihei: None. H. Yako: None. N. Nakamura: None. K. Naruse: None. T. Himeno: None. Y. Kato: None. J. Nakamura: None. H. Kamiya: Research Support; Current; Boehringer Ingelheim International GmbH, CBC, Daiichi Sankyo, EA Pharma, Eli Lilly and Company, Fukuda Denshi, Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Kirin Co., Ltd., MSD, Mochida Pharmaceutical Co., Ltd., Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Parexel International, Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited. Speaker's Bureau; Current; Abbott Japan Co., Ltd., Array BioPharma Inc., Astellas Pharma Inc., AstraZeneca, Bayer AG, Chugai Pharmaceutical Co., Ltd., EA Pharma, Eli Lilly and Company, Eisai Inc., Fukuda Denshi, GlaxoSmithKline plc., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Kirin Co., Ltd., Novartis Pharma K.K., Novo Nordisk, Mitsubishi Tanabe Pharma Corporation, MSD, Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Sanwa Kagaku Kenkyusho, Taisho Pharmaceutical Holdings Co., Ltd., Teijin Pharma Limited, Viatris Inc. K. Sango: None. K. Kato: Speaker's Bureau; Current; Daiichi Sankyo.

ABSTRACT Aims/Introduction As a common chronic complication, diabetic neuropathy affects a substantial number of individuals with diabetes mellitus, with limited therapeutic options addressing the underlying pathogenesis. The glucose‐lowering action of imeglimin is mediated through improved insulin sensitivity in peripheral organs, including the skeletal muscle and liver, along with augmented insulin release from β‐cells. Imeglimin exerts its effects in part by modulating mitochondrial complex I, leading to the reduced production of reactive oxygen species and protection against metabolic stress. Despite these beneficial effects, the effect of imeglimin on diabetic neuropathy remains unclear. In this study, we evaluated whether imeglimin ameliorated peripheral nerve dysfunction in streptozotocin (STZ)‐induced diabetic rats. Materials and Methods The rats received imeglimin (200 mg/kg twice daily) or vehicle for 4 weeks, and the sensory nerve conduction velocity (SNCV), motor nerve conduction velocity (MNCV), sciatic nerve blood flow (SNBF), and intraepidermal nerve fiber density (IENFD) were assessed. Neurite outgrowth was examined in ND7/23 cells derived from the dorsal root ganglion. Results Imeglimin treatment significantly improved SNCV, SNBF, and IENFD without affecting blood glucose levels, indicating neuroprotective effects, independent of glycemic control. Furthermore, imeglimin enhanced neurite outgrowth in ND7/23 cells, demonstrating its direct neurotrophic effect. These findings indicate that imeglimin protects against diabetic neuropathy by enhancing nerve blood flow and promoting neurite growth independent of the systemic control of glycemia. Conclusions This study provides supporting evidence for the potential therapeutic application of imeglimin in diabetic neuropathy.

Introduction and Objective: Imeglimin is an oral antidiabetic agent with beneficial effects on mitochondrial function. Studies have shown that imeglimin reduces gluconeogenesis and stimulates muscle glucose uptake, thereby improving insulin resistance. Additionally, it promotes insulin secretion by increasing NAD+ levels in pancreatic β-cells. Studies have also demonstrated that imeglimin reduces mitochondrial oxidative stress and the activity of mitochondrial complex I in hepatic mitochondria of mice fed high-fat or high-sucrose diets. However, the effects of imeglimin on diabetic neuropathy remain unclear. Therefore, we investigated the effects of imeglimin on diabetic neuropathy in streptozotocin (STZ)-induced diabetic rats. Methods: Male Wistar rats were injected intraperitoneally with vehicle or STZ to induce diabetes. Four weeks after STZ injection, rats were orally gavaged with vehicle or imeglimin (200 mg/kg) twice daily for four weeks. Subsequently, assessments of mortor nerve conduction velocity (MNCV), sciatic nerve conduction velocity (SNCV), sciatic nerve blood flow (SNBF) were performed. Results: Imeglimin did not significantly affect body weight or blood glucose levels. Compared to controls, diabetic rats exhibited a trend toward decreased MNCV, which was attenuated by imeglimin. Diabetic rats also showed significant reductions in SNCV, and SNBF compared to controls. Imeglimin treatment significantly ameliorated the reduction in SNCV and SNBF. Conclusion: These findings from STZ-induced diabetic rats indicate the therapeutic potential of imeglimin for diabetic neuropathy. W. Nihei: None. A. Kato: None. T. Sato: None. T. Himeno: None. N. Nakamura: None. K. Sango: None. K. Naruse: None. J. Nakamura: Speaker's Bureau; Daiichi Sankyo, Novo Nordisk. H. Kamiya: Research Support; Sumitomo Dainippon Pharma Co., Ltd. Speaker's Bureau; Sumitomo Dainippon Pharma Co., Ltd. K. Kato: Speaker's Bureau; Daiichi Sankyo. JSPS KAKENHI (24K09971)

Introduction and Objective: Diabetes mellitus is known to be associated with a higher incidence and severity of periodontal disease, although the mechanism remains unclear. We and others previously demonstrated the involvement of increased oxidative stress, polyol pathway, and advanced glycation end products on periodontitis in subjects with diabetes like other chronic diabetic complications. Mitochondrial dysfunction is thought to be one of the common mechanisms of diabetic complications. To clarify the impacts of mitochondrial dysfunction on periodontitis in diabetes, we investigated the effect of imeglimin. Methods: Diabetes was induced by intraperitoneal injection of streprozotocin(STZ) in six-week-old male Sprague-Dawley rats. 2 weeks after STZ administration, experimental periodontitis was induced by ligating nylon sutures around the cervical area of maxillary second molar teeth. Imeglimin was administered into Half of the diabetic rats for 2 weeks through an osmotic pump placed in the back skin. Two weeks after the induction of periodontitis, the rats were slaughtered, and maxillary periodontal tissues were collected and analyzed. Micro-CT analysis of maxillary alveolar bone was performed to evaluated alveolar bone loss. Results: Imeglimin did not affect the blood glucose levels in diabetic rats. Periodontitis induced inflammatory cell infiltration of the gingiva.Periodontitis in diabetic rats showed increased inflammatory cell infiltration, increased gene expressions of TNF-α and iNOS in the gingiva, and increased alveolar bone resorption compared to that in normal rats. Administration of imeglimin significantly decreased the gene expressions of inflammatory cytokines and inflammatory cell infiltration in gingiva of diabetic rats. Imeglimin also significantly improved alveolar bone resorption in diabetic rats. Conclusion: These results suggest that mitochondrial dysfunction may be involved in the mechanism of periodontal exacerbation in diabetes mellitus. Disclosure S. Kondo: None. K. Kojima: None. H. Airi: None. K. Katsumata: None. N. Nakamura: None. M. Miyabe: None. S. Sasajima: None. R. Ozaki: None. M. Yamaguchi: None. N. Sawada: None. T. Minato: None. T. Saiki: None. T. Ohno: None. T. Kikuchi: None. A. Mitani: None. K. Naruse: None.

Introduction and Objective: Periodontitis is a chronic inflammatory disease characterized by periodontal tissue destruction by bacterial factors. Periodontal disease is considered one of the complications of diabetes due to the high prevalence and severity of periodontal disease. However, the detailed mechanism by which diabetes aggravates periodontitis is unclear. In this study, we focused on histone modifications from the viewpoint of metabolic memory. Methods: We examined the effects of histone modifications on the gums in diabetes. Diabetes was induced by administering streptozotocin (STZ; 60 mg/kg) intraperitoneally in 6-week-old male Sprague-Dawley rats. To determine the involvement of histone modifications in gene expression changes in hyperglycemic conditions, human gingival fibroblasts (hGFs) were cultured for 1 week in high glucose conditions (27.5 mM) with sinefungin, a SET-type histone methyltransferase (HMT) inhibitor. Results: Induction of diabetes significantly increased the expression of trimethylation of histone H3 lysine 4 (H3K4me3) and Su (var) 3-9, enhancer-of-zeste, and trithorax domain 1A (SETD1A), a component of a histone methyltransferase, in the gums. High glucose significantly increased the expression of H3K4me3 and SETD1A proteins in hGF, and sinefungin suppressed these protein expressions. High glucose also significantly increased matrix metalloproteinase 1 (MMP1) and MMP13 gene expressions in hGF, which were suppressed by sinefungin in high glucose conditions. Although gene expression of tissue inhibitor metalloproteinase 1 (TIMP1) was unchanged under all conditions, the MMP/TIMP ratio was significantly higher in high glucose condition. Sinefungin canceled the increase of MMP/TIMP ratio in high glucose condition. Conclusion: In summary, we found that diabetes induces histone modification of H3K4me3 via upregulation of SETD1A in gingival tissue. These histone modifications may increase the susceptibility of diabetes to periodontal disease. Disclosure K. Kojima: None. N. Nakamura: None. M. Miyabe: None. T. Kikuchi: None. S. Kondo: None. N. Sawada: None. A. Hayashi: None. T. Minato: None. T. Saiki: None. S. Sasajima: None. R. Ozaki: None. A. Mitani: None. K. Naruse: None.

Despite the well-established bidirectional relationship between periodontal disease and diabetes, limited research has examined the role of regular dental check-ups in patients with type 2 diabetes. This study analyzed the relationship between periodontal disease status, dental visit patterns, and diabetes status using baseline data from the Japan Diabetes Complication and its Prevention (JDCP) prospective study. Among 6,099 patients with diabetes (aged 40–75 years), 685 with type 2 diabetes who underwent dental examinations were included. Trained dentists collected periodontal disease data using self-report questionnaires and periodontal examination.Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). Participants who did not undergo regular dental check-ups exhibited higher HOMA-IR values than those who did. Logistic regression analyses revealed a significant association between insulin resistance and regular dental check-ups (odds ratio = 2.33, 95% confidence interval = 1.07–5.09, P = 0.034). Approximately 50% of the respondents did not undergo regular dental check-ups. Individuals who undergo dental check-ups may experience improved local periodontal inflammation through treatment, potentially reducing systemic inflammation and infection compared to those who do not. This reduction in systemic inflammation and infection could contribute to improved insulin resistance.

Oxidative stress in adipose tissue may alter the secretion pattern of adipocytokines and potentially promote atherosclerosis. However, the therapeutic role of hydrogen in adipose tissue under oxidative stress remains unclear. In this study, subcutaneous adipose tissue (SCAT) was collected from the mid-thoracic wounds of 12 patients who underwent open-heart surgery with a mid-thoracic incision. The adipose tissue was then immersed in a culture medium dissolved with hydrogen, which was generated using a hydrogen-generating device. The weight of the adipose tissue was measured before and after hydrogenation, and the tissue was immunostained for nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and superoxide dismutase (SOD), which are markers of oxidative stress. The immunostaining results showed that HO-1 and Nrf2 expression levels were significantly decreased in the hydrogenated group, whereas SOD expression levels increased, but did not attain statistical significance. Image analysis of adipose tissue revealed that a reduction in adipocyte size. Furthermore, hydrogenated adipose tissue showed a trend toward increased gene expression levels of adiponectin and decreased gene expression levels of chemerin, an adipocytokine involved in adipogenesis. These results demonstrated the therapeutic potential of hydrogen gas for oxidative stress in adipose tissue and for reducing adipocyte size.

ABSTRACT Aims/Introduction Orthodontic treatment involves alveolar bone remodeling in response to mechanical loading, resulting in tooth movement through traction‐side bone formation and compression‐side bone resorption. However, there are conflicting reports regarding alveolar bone resorption during the orthodontic treatment of patients with diabetes. Materials and Methods Diabetes was induced in 8‐week‐old C56BL/6J mice using streptozotocin (STZ). Four weeks after the injection of STZ, a mechanical load was applied between the first and second molars on the right side of the upper jaw using the Waldo method with orthodontic elastics in diabetic (DM) and normal (N) mice tooth movement, gene expression, osteoclast counts, alveolar bone residual volume, and bone beam structure were evaluated. Results The duration until spontaneous elastic loss was significantly longer in the DM group, suggesting that tooth movement may be inhibited in the diabetic state. The number of osteoclasts at 7 days after mechanical loading and the alveolar bone resorption were both significantly lower in the DM group. The gene expression levels of vascular endothelial growth factor (VEGF), a protein related to alveolar bone remodeling, and specificity protein 1 (SP1), a transcription factor of the VEGF gene, were significantly lower in the DM group than in the N group on the compression side of mechanical loading. Conclusions Mechanical loading‐induced alveolar bone remodeling is suppressed in the diabetic state. Our results suggest that VEGF is a key molecule involved in impaired bone remodeling under mechanical loading in the diabetic state.

Individuals suffering from diabetic polyneuropathy (DPN) experience debilitating symptoms such as pain, paranesthesia, and sensory disturbances, prompting a quest for effective treatments. Dipeptidyl-peptidase (DPP)-4 inhibitors, recognized for their potential in ameliorating DPN, have sparked interest, yet the precise mechanism underlying their neurotrophic impact on the peripheral nerve system (PNS) remains elusive. Our study delves into the neurotrophic effects of DPP-4 inhibitors, including Diprotin A, linagliptin, and sitagliptin, alongside pituitary adenylate cyclase-activating polypeptide (PACAP), Neuropeptide Y (NPY), and Stromal cell-derived factor (SDF)-1a—known DPP-4 substrates with neurotrophic properties. Utilizing primary culture dorsal root ganglia (DRG) neurons, we meticulously evaluated neurite outgrowth in response to these agents. Remarkably, all DPP-4 inhibitors and PACAP demonstrated a significant elongation of neurite length in DRG neurons (PACAP 0.1 μM: 2221 ± 466 μm, control: 1379 ± 420, p < 0.0001), underscoring their potential in nerve regeneration. Conversely, NPY and SDF-1a failed to induce neurite elongation, accentuating the unique neurotrophic properties of DPP-4 inhibition and PACAP. Our findings suggest that the upregulation of PACAP, facilitated by DPP-4 inhibition, plays a pivotal role in promoting neurite elongation within the PNS, presenting a promising avenue for the development of novel DPN therapies with enhanced neurodegenerative capabilities.

Hyperglycemia-induced oxidative stress is a major cause of the pathogenesis of diabetic neuropathy, and hyperglycemia-induced mitochondrial ROS production is considered as a significant mechanism of increased oxidative stress. On the other hand, imeglimin is the first in a new glimin class of anti-diabetic drugs targeting mitochondrial bioenergetics. In addition, imeglimin has been reported to enhance insulin secretion by increasing nicotinamide adenine dinucleotide (NAD+) levels in rat islets via the salvage pathway involving nicotinamide phosphoribosyltransferase (NAMPT). Moreover, NAD+ has been shown to modulate sirtuin and PGC1α, which in turn ameliorate mitochondrial dysfunction. We investigated the effects of imeglimin on high glucose-induced cell death and mitochondrial dysfunction in Schwann cells. In addition, the effects of imeglimin on NAD+ levels, NAMPT activity, the rate-limiting enzyme in the salvage pathway for NAD+ synthesis, and SIRT1 expression, a longevity gene, were evaluated. Immortalized adult mouse Schwann (IMS32) cells were cultured in 5.5 mM normal glucose (NG) and 25 mM high glucose (HG) medium. Compared to NG, HG decreased cell viability and increased mitochondrial oxidative stress. HG decreased mitochondrial membrane potential, increased mitochondrial oxygen consumption rate (OCR), increased activity of complex I and decreased ATP levels. Imeglimin ameliorated the reduction in cell viability and improved these mitochondrial dysfunctions. In addition, imeglimin increased NAMPT activity and NAD+ levels in IMS32 cells under HG conditions. Furthermore, imeglimin also ameliorated the reduction in SIRT1 expression by HG. These results suggest that imeglimin may prevent diabetic neuropathy by attenuating hyperglycemia-induced mitochondrial dysfunction and cell death in Schwann cells, at least in part, through the enhancement of SIRT1 and NAD+ biosynthesis. Disclosure A. Kato: None. W. Nihei: None. H. Yako: None. K. Sango: None. N. Nakamura: None. K. Naruse: None. T. Himeno: None. Y. Kato: None. J. Nakamura: None. H. Kamiya: Speaker's Bureau; Novo Nordisk, Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Eli Lilly and Company, Boehringer-Ingelheim, Daiichi Sankyo, AstraZeneca, Ono Pharmaceutical Co., Ltd., Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Kowa Company, Ltd., Novartis Pharmaceuticals Corporation, Merck & Co., Inc., Sanwa Kagaku, Otsuka Pharmaceuticals Corporation. Research Support; Kissei Pharmaceutical Co., Ltd., Ono Pharmaceutical Co., Ltd., Eli Lilly and Company, Taiho Pharmaceutical Co. Ltd., Sumitomo Dainippon Pharma Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Japan Tobacco Inc, Novo Nordisk. Speaker's Bureau; Taiho Pharmaceutical Co. Ltd., Astellas Pharma Inc., Kyowa Kirin Co., Ltd., Teijin Pharma Limited, Bayer Inc. K. Kato: None.

Significant advancements have been made in diagnostic methods for early-stage diabetic polyneuropathy. Early and accurate diagnosis of diabetic polyneuropathy is crucial for preventing further complications and enabling timely intervention. Furthermore, there is a need for an objective numerical value to evaluate the early stage of diabetic polyneuropathy.

Objectives: Diabetic peripheral neuropathy is associated with neurogenic muscle atrophy. The development of successful therapies for nerve damage and muscle atrophy must be needed for patients with DPN. In this study, we investigated the effects of dental pulp stem cell (DPSC) transplantation on skeletal muscles in streptozotocin (STZ)-induced diabetic rats. Methods: DPSCs were isolated and expanded from dental pulp of 6-wk old Sprague-Dawley rats. Cultured DPSCs were transplanted into the unilateral hindlimb skeletal muscles of normal and streptozotocin-induced diabetic rats. Four weeks after DPSC transplantation, the impacts of DPSC transplantation on hindlimb skeletal muscles and peripheral nerves were examined. Results: Diabetic rats showed significant decreased the muscle fiber cross-sectional area and increased the CD68-positive inflammatory cell infiltration in gastrocnemius muscles, which were ameliorated by DPSC transplantation. Gene expression analyses revealed that DPSC transplantation increased PGC1α and suppressed atrogin-1 and TNF-α in diabetic skeletal muscles. DPSC transplantation significantly ameliorated decreased-FGF2 gene expression with the improvement of motor and sensory nerve conduction velocities in diabetic rats. Conclusions: We identified that DPSC transplantation into hindlimb skeletal muscle could ameliorate diabetic muscle atrophy and inflammation and improve diabetic peripheral neuropathy. Disclosure K. Naruse: None. M. Omi: None. M. Hata: None. N. Nakamura: None. M. Miyabe: None. S. Sasajima: None. R. Ozaki: None. S. Ozawa: None. J. Takebe: None. T. Matsubara: None.

Periodontal disease is considered one of the diabetic complications with high morbidity and severity. Recent studies demonstrated the involvement of the epigenome on diabetic complications. Histone modifications change chromatin architecture and gene activation. Histone modifications have been reported to alter chromatin structure and regulate gene transcription. In this study, we investigated the impacts of H3 lysine 4 trimethylation (H3K4me3) and specific histone methyltransferases of H3K4 methylation, su(var)3-9, enhancer-of-zeste, and trithorax domain 1A (SETD1A) on periodontal tissue affected by the diabetic condition. We observed the increase in H3K4me3 and SETD1A in gingival tissue of diabetic rats compared with the normal rats. Cultured human fibroblasts (hGFs) confirmed a high glucose-induced increase in H3K4me3 and SETD1A. We further demonstrated that high glucose increased the gene expression of matrix metalloproteinase (MMP) 1 and MMP13, which were canceled by sinefungin, an SETD1A inhibitor. Our investigation suggests that diabetes triggers histone modifications in the gingival tissue, resulting in gingival inflammation. Histone modifications may play crucial roles in the development of periodontal disease in diabetes.

BackgroundAngiopoietin-like protein 4 (ANGPTL4) is produced in chronic or acute inflammation. Although ANGPTL4 increases in the periodontal ligament fibroblasts during hypoxia, the involvement and role of ANGPTL4 in periodontitis have not been elucidated. ObjectiveIn this study, we investigated whether ligature-induced experimental periodontitis and/or Porphyromonas gingivalis lipopolysaccharides (Pg-LPS) would upregulate ANGPTL4 expression and whether ANGPTL4 would somehow involve in the expression of matrix metalloproteinases (MMPs) which are key molecules in the process of periodontal tissue destruction. MethodsExperimental periodontitis was induced in 6-week-old male Sprague-Dawley rats by placing a nylon suture around the neck of the maxillary second molar. Two weeks after the induction of periodontitis, the periodontal tissue was excised and analyzed by histological/immunohistochemical staining and gene expression analyses. Human gingival fibroblasts (hGFs) were stimulated with Pg-LPS. The gene expression of ANGPTLs and receptors involved in ANGPTL4 recognition were observed. We also confirmed the changes in gene expression of MMPs upon stimulation with human ANGPTL4. Furthermore, we downregulated ANGPTL4 expression by short interfering RNA in hGFs and investigated the effect of Pg-LPS on MMP production. ResultsInduction of periodontitis significantly increased the expression of ANGPTL4 in the gingiva. Pg-LPS significantly increased the gene and protein expression of ANGPTL4 in hGFs, but not the gene expression of other ANGPTLs or ANGPTL receptors. Recombinant human ANGPTL4 significantly increased MMP13 gene expression in hGFs. We also confirmed that MMP13 expression was increased in the gingiva during experimental periodontitis. Pg-LPS induced MMP13 gene expression in hGFs, which was abolished by the suppression of ANGPTL4. These results suggest the pivotal role of ANGPTL4 in periodontitis. ConclusionPeriodontitis increases ANGPTL4 expression in the gingiva, further suggesting that increased ANGPTL4 may be a factor involved in enhancing MMP13 expression.

Atherosclerosis is a major cause of mortality worldwide. The initial change in atherosclerosis is intimal thickening due to muscle cell proliferation and migration. A correlation has been observed between periodontal disease and atherosclerosis. Here, we investigated the proliferation and migration of human aortic smooth muscle cells (HASMCs) using Porphyromonas gingivalis-derived LPS (Pg-LPS). To elucidate intracellular signaling, toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) of HASMCs were knocked down, and the role of these molecules in Pg-LPS-stimulated proliferation and migration was examined. The role of mitogen-activated protein kinase (MAPK) in HASMC proliferation and migration was further elucidated by MAPK inhibition. Pg-LPS stimulation increased the proliferation and migration of HASMCs and activated the TLR4/MyD88 pathway. TLR4 knockdown inhibited Pg-LPS stimulated HASMCs proliferation and migration. Pg-LPS stimulation led to the phosphorylation of P38 MAPK, JNK, and ERK, and MyD88 knockdown inhibited the phosphorylation of P38 MAPK and JNK but not ERK. P38 MAPK and SAPK/JNK inhibition did not suppress the proliferation of HASMCs upon Pg-LPS stimulation, but ERK inhibition significantly inhibited proliferation. SAPK/JNK and ERK inhibition suppressed Pg-LPS-stimulated migration of HASMCs. In conclusion, our findings suggest that Pg-LPS may promote atherosclerosis via the activation of MAPK through TLR4.

Glucose-dependent insulinotropic polypeptide (GIP) exhibits extrapancreatic effects through the receptor for GIP (GIPR). In this study, we used Ni-Ti Closed Coil Spring (Ni-Ti) in GIPR-deficient mice (GIPRKO) and wild-type mice (WT) to investigate the effect of GIP on force-induced bone remodeling due to orthodontic tooth movement. It was investigated. Ni-Ti was attached between the maxillary bone and the maxillary left first molar (M1) of GIPRKO and WT, and mechanical load was applied by pulling the M1 in the mesial direction. Remaining amount and bone quality were measured. A histological examination of the maxilla was also performed. As a result, compared to WT, GIPRKO showed a significant increase in tooth movement distance and a significant decrease in residual alveolar bone mass. TRAP staining showed an increase in osteoclasts in GIPRKO compared to WT on the tooth moving side. We also found that GIPRKO reduced osteoblasts in the steady state and suppressed osteoblasts after tooth movement. These results suggest that GIPRK impairs bone remodeling through increased bone resorption due to mechanical load, and that GIP plays an important role in bone remodeling. Disclosure T.Yamauchi: None. S.Goto: None. K.Naruse: None. N.Nakamura: None. M.Miyabe: None. M.Ito: None. R.Hoshino: None. S.Kanada: None. T.Sekiya: None. T.Matsubara: None. K.Miyazawa: None.

Background:Smoking affects wound healing and is associated with dental implant failure. Heated tobacco products (HTPs) appear to be less harmful than conventional cigarettes (CCs); however, there is limited analytical data to support this claim. This study aimed to compare HTPs and CCs for their impact on wound healing using L929 mouse fibroblast cells and evaluate whether HTPs also lead to failure in implant therapy. Materials and methods:Cigarette smoke extract (CSE) was obtained from CCs (Marlboro, Philip Morris) and HTPs (Marlboro Heat Sticks Regular for IQOS, Philip Morris) and initiated a wound-healing assay with a cell-free area created in the centre of a titanium plate by sticking a 2-mm-width line tape. The L929 mouse fibroblast cells were exposed with 2.5 and 5% CSE from HTPs and CCs and then seeded in the titanium plate. A scratch wound-healing assay was initiated when all samples were at 80% confluence. The number of cells migrating to the wound site was counted after 12, 24, and 48 h. Results:Cell migration decreased after CSE exposure from both CCs and HTPs. At each time-point with 2.5% CSE, cell migration in the HTP group was less than that of the CC group. There were significant differences between the 2.5% CC and 2.5% HTP groups and the 5% CC and 5% HTP groups after 24 h. HTPs and CCs had similar effects in the wound-healing assay. Conclusion:Therefore, HTP use may be a risk factor for poor dental implant healing.