Detection of senescent cells in the mucosal healing process on type 2 diabetic rats after tooth extraction for biomaterial development.

The delayed mucosal healing of tooth extraction sockets in diabetes has few known effective treatment strategies, and its underlying mechanism remains unknown. Senescent cells may play a pivotal role in this delay, given the well-established association between diabetes, senescent cells, and wound healing. Here, we demonstrated an increase in p21- or p16-positive senescent cells in the epithelial and connective tissues of extraction sockets in type 2 diabetic rats compared to those in control rats. Between 7 and 14 days after tooth extraction, a decrease in senescent cells and improvement in re-epithelialization failure were observed in the epithelium, while an increase in senescent cells and persistence of inflammation were observed in the connective tissue. These results suggest that cellular senescence may have been induced by diabetes and contributed to delayed mucosal healing by suppressing re-epithelization and persistent inflammation. These findings provide new targets for treatment using biomaterials, cells, and drugs.

Acute effects of low-intensity one-legged electrical muscle stimulation on arterial stiffness in experimental and control limbs.

The aim of this study was to examine the acute effects of low-intensity one-legged electrical muscle stimulation (EMS) for skeletal muscle on arterial stiffness in EMS and non-EMS legs. Eighteen healthy subjects received two different protocols (Control (CT) and Experimental (ET) trials) in random order on separate days. EMS was applied to the left lower limb at 4 Hz for 20 min at an intensity corresponding to an elevation in pulse rate of approximately 15 beats/min (10.9 ± 5.1% of heart rate reserve). Before and after the experiment, arterial stiffness parameters in the control right leg (CRL) and control left leg (CLL) in CT and non-EMS leg (NEL) and EMS leg (EL) in ET were assessed by pulse wave velocity (baPWV, faPWV) and cardio-ankle vascular index (CAVI). No significant changes in all parameters were observed in either leg in CT. Conversely, in ET, low-intensity, single-leg EMS significantly reduced CAVI, baPWV, and faPWV in the EL, but not in the NEL. Acute, low-intensity single-leg EMS reduces arterial stiffness only in the EL. These data support our idea that physical movement-related regional factors rather than systematic factors are important for inducing acute reductions in arterial stiffness.

Enhancing the Thermal Conductivity of CNT/AlN/Silicone Rubber Composites by Using CNTs Directly Grown on AlN to Achieve a Reduced Filler Filling Ratio.

Achieving the thermal conductivity required for efficient heat management in semiconductors and other devices requires the integration of thermally conductive ceramic fillers at concentrations of 60 vol% or higher. However, an increased filler content often negatively affects the mechanical properties of the composite matrix, limiting its practical applicability. To address this issue, in this paper, we present a new strategy to reduce the required ceramic filler content: the use of a thermally conductive ceramic composite filler with carbon nanotubes (CNTs) grown on aluminum nitride (AlN). We combined catalyst coating technology with vacuum filtration to ensure that the catalyst was uniformly applied to micrometer-sized AlN particles, followed by the efficient and uniform synthesis of CNTs using a water-assisted process in a vertical furnace. By carefully controlling the number of vacuum filtration cycles and the growth time of the CNTs, we achieved precise control over the number and length of the CNT layers, thereby adjusting the properties of the composite to the intended specifications. When AlN/CNT hybrid fillers are incorporated into silicone rubber, while maintaining the mechanical properties of rubber, the thermal diffusivity achieved at reduced filler levels exceeds that of composites using AlN-only or simultaneous AlN and CNTs formulations. This demonstrates the critical influence of CNTs on AlN surfaces. Our study represents a significant advancement in the design of thermally conductive materials, with potential implications for a wide range of applications.

Retrospective study on the effect of adipose stem cell transplantation on jaw bone regeneration.

PURPOSE: In patients with jaw bone atrophy, dental implant therapy requires bone augmentation on the alveolar ridge. Common methods are autologous bone transplantation or bone substitutes. The latter technique is less surgically invasive because it does not require bone harvesting; however, blood supply from the surrounding tissues and local differentiation of osteoblasts are not guaranteed, so adequate bone regeneration for dental implant therapy is often not achieved. Therefore, at our hospital we introduced a bone regenerative medicine technique that uses adipose stem cells (ASCs) from adipose tissue. The new approach is less surgically invasive and appears to have a better effect on bone regeneration. The current retrospective study aimed to demonstrate the efficacy of ASC transplantation in patients who underwent alveolar ridge bone augmentation at our hospital. METHODS: We compared medical records, postoperative radiographic findings, and histological results from patients treated between January 2018 and March 2022 by augmentation of the jaw bone with bone substitutes (carbonate apatite) mixed with ASCs (ASCs+ group) and those treated with bone substitutes (carbonate apatite) alone (ASCs- group). RESULTS: After 6 months, the survival rate of augmented bone and the gray scale value in dental cone beam computed tomography (a bone density index) were significantly higher in the ASCs+ group than in the ASCs- group. Histological analysis at 6 months showed more adequate bone tissue regeneration in the ASCs+ group. CONCLUSIONS: The findings suggest the effectiveness of using ASCs in bone augmentation on the alveolar ridge in patients with jaw bone atrophy.

Evaluation of the benefits of neutral bicarbonate ionized water baths in an open-label, randomized, crossover trial.

We previously demonstrated that neutral bicarbonate ionized water (NBIW) bathing enhances blood flow by bicarbonate ions and described the underlying mechanism. However, additional clinical investigation was warranted to investigate the efficacy of NBIW bathing. Hence, we performed a randomized, open-label, crossover trial to examine the effects of NBIW bathing on mental stress, sleep, and immune function. Participants who regularly felt stressed were randomly assigned to NBIW or regular bathing for 4 weeks. Mental stress was assessed with the Brief Job Stress Questionnaire (BJSQ) and the Profile of Mood States Second Edition; sleep quality, with the Pittsburgh Sleep Quality Index Japanese version (PSQI-J) and actigraphy; and immune function, with laboratory tests. PSQI-J scores and actigraphy sleep latency and bed out latency improved significantly more with NBIW bathing than with regular bathing (p < 0.05). Furthermore, NBIW bathing reduced both stress-induced fluctuations in CD4+ and CD8+ T cell counts and fluctuations in the naive to memory T cell ratio and neutrophil phagocytosis, indicating improved immune function. These findings suggest that daily NBIW bathing could improve mental stress, sleep quality, and immune function and bring about positive health effects in those who experience stress in their daily lives.

Carbonate apatite versus ß-tricalcium phosphate for rat vertical bone augmentation: A comparison of bioresorbable bone substitutes using polytetrafluoroethylene tubes.

This study radiologically and histologically compared two bioresorbable bone substitutes with different compositions carbonate apatite (Cytrans® Granules; CGs) and ß-tricalcium phosphate (ß-TCP) for vertical bone augmentation on a rat skull using a polytetrafluoroethylene (PTFE) tubes. This PTFE tube was placed at the center of the skull, fixed with Super Bond, and augmented with CGs or ß-TCP granules. Specimens with surrounding tissue were harvested at 4, 8, and 12 weeks postoperatively, and radiological and histological evaluations were performed. The bone volume to total volume ratio (BV/TV) of the ß-TCP-implanted group was markedly higher than that of the CG-implanted group at 4 and 12 weeks postoperatively. Compared to CGs, ß-TCP exhibited the ability to form blood vessels into the graft material for a short period after transplantation, as well as an elevated production of collagen into ß-TCP granules during the bone formation process.

Diagnostic Utility of 99m Tc-MDP Bone Scintigraphy for Nivolumab-Induced Inflammatory Arthritis.

ABSTRACT: Immune checkpoint inhibitors can revive exhausted helper T-cells, and inflammatory cell reactivation may cause autoimmune disease-like conditions. Drug-induced arthritis is an immune-related adverse event, but the diagnostic approach is undefined. We present the diagnostic utility of 99m Tc-MDP bone scintigraphy for nivolumab-induced inflammatory arthritis. A 67-year-old man with hypopharyngeal carcinoma presented bilateral multiple metacarpophalangeal joint pain and swelling at each nivolumab administration. Regular imaging findings were atypical for inflammatory arthritis and did not fulfill the criteria for rheumatoid arthritis. We diagnosed nivolumab-induced inflammatory arthritis based on clinical symptoms and the symmetrical moderate uptake of the affected joints on 99m Tc-MDP bone scintigraphy.

Bioactive Polyetheretherketone with Gelatin Hydrogel Leads to Sustained Release of Bone Morphogenetic Protein-2 and Promotes Osteogenic Differentiation.

Polyetheretherketone (PEEK) is one of the most promising implant materials for hard tissues due to its similar elastic modulus; however, usage of PEEK is still limited owing to its biological inertness and low osteoconductivity. The objective of the study was to provide PEEK with the ability to sustain the release of growth factors and the osteogenic differentiation of stem cells. The PEEK surface was sandblasted and modified with polydopamine (PDA). Moreover, successful sandblasting and PDA modification of the PEEK surface was confirmed through physicochemical characterization. The gelatin hydrogel was then chemically bound to the PEEK by adding a solution of glutaraldehyde and gelatin to the surface of the PDA-modified PEEK. The binding and degradation of the gelatin hydrogel with PEEK (GPEEK) were confirmed, and the GPEEK mineralization was observed in simulated body fluid. Sustained release of bone morphogenetic protein (BMP)-2 was observed in GPEEK. When cultured on GPEEK with BMP-2, human mesenchymal stem cells (hMSCs) exhibited osteogenic differentiation. We conclude that PEEK with a gelatin hydrogel incorporating BMP-2 is a promising substrate for bone tissue engineering.

Life Cycle Plasticity in Typhula and Pistillaria in the Arctic and the Temperate Zone.

Typhulaceae Jülich is one of the cold-adapted fungal families in basidiomycetes. The representative genera, Typhula (Pers.) Fr. and Pistillaria Fr., are distinguished by the discontinuity between stems and hymenia in the former and the continuity in the latter (Fries 1821). This taxonomic criterion is ambiguous, and consequently, the view of Karsten (1882) has been widely accepted: Typhula develops basidiomata from sclerotia, while basidiomata develop directly from substrata in Pistillaris. However, Corner (1970) observed basidiomata of Pistillaria petasitis S. Imai developing from sclerotia in Hokkaido, Japan. We later recognized that P. petasitis basidiomata also emerged directly from substrates on the ground in Hokkaido. An aberrant form of Typhula hyperborea H. Ekstr. was found in Upernavik, West Greenland. This specimen had a stem-like structure on a Poaceae plant, and sclerotia developed on its tip. Similar phenomena were found in other Typhula species in Japan. In this study, we aimed to elucidate the life cycle plasticity in the genera Typhula and Pistillaria through the interactions between their ecophysiological potential and environmental conditions in their localities. We collected and prepared strains of the above fungi from sclerotia or basidiomata, and we elucidated the taxonomical relationship and determined the physiological characteristics of our strains. Our findings imply that both Typhula and Pistillaria have the potential to produce sclerotia as well as the capacity for mycelial growth at ambient air temperatures in each locality where samples were collected. These findings suggest that Typhula spp. develope basidiomata not only from the sclerotia dispersed by the basidiospores but also from mycelia generated by the spore germination, which formed basidiomata multiple times, depending on their growth environments.

A Case of Fungal Maxillary Sinusitis Extending to the Contralateral Side Through the Nasal Septum.

Fungal rhinosinusitis (FRS) presents as various phenotypes ranging from asymptomatic colonization to life-threatening infections. Here, we report an atypical case of FRS of the left maxillary sinus that extended to the contralateral maxillary sinus through the nasal septum. An 80-year-old woman with a history of osteoporosis was referred to our hospital for further management of headaches and chronic rhinosinusitis. Computed tomography (CT) of the sinus revealed a mass lesion with calcification in the left maxillary sinus, extending to the contralateral maxillary sinus through the nasal septum. T1-weighted and T2-weighted magnetic resonance imaging revealed a mass lesion with low-intensity signals. Endoscopic sinus surgery was performed for the diagnosis and treatment. Histopathological examination revealed fungal elements in the caseous material of the left maxillary sinus. However, no tissue-invasive fungal forms were found. Additionally, eosinophilic mucin was not observed. Based on these findings, the patient was diagnosed with fungus ball (FB). To the best of our knowledge, there are no reports of a FB extending contralaterally through the nasal septum. This report serves as a reminder that FB can extend into contralateral paranasal sinuses through the nasal septum and the possibility that osteoporosis is a cause of extensive bone destruction.

RANKL+ senescent cells under mechanical stress: a therapeutic target for orthodontic root resorption using senolytics.

In dentistry, orthodontic root resorption is a long-lasting issue with no effective treatment strategy, and its mechanisms, especially those related to senescent cells, remain largely unknown. Here, we used an orthodontic intrusion tooth movement model with an L-loop in rats to demonstrate that mechanical stress-induced senescent cells aggravate apical root resorption, which was prevented by administering senolytics (a dasatinib and quercetin cocktail). Our results indicated that cementoblasts and periodontal ligament cells underwent cellular senescence (p21+ or p16+) and strongly expressed receptor activator of nuclear factor-kappa B (RANKL) from day three, subsequently inducing tartrate-resistant acid phosphatase (TRAP)-positive odontoclasts and provoking apical root resorption. More p21+ senescent cells expressed RANKL than p16+ senescent cells. We observed only minor changes in the number of RANKL+ non-senescent cells, whereas RANKL+ senescent cells markedly increased from day seven. Intriguingly, we also found cathepsin K+p21+p16+ cells in the root resorption fossa, suggesting senescent odontoclasts. Oral administration of dasatinib and quercetin markedly reduced these senescent cells and TRAP+ cells, eventually alleviating root resorption. Altogether, these results unveil those aberrant stimuli in orthodontic intrusive tooth movement induced RANKL+ early senescent cells, which have a pivotal role in odontoclastogenesis and subsequent root resorption. These findings offer a new therapeutic target to prevent root resorption during orthodontic tooth movement.

Visualization of deformation-induced changes in carbon nanotube networks in rubber composites using lock-in thermography.

In this study, we used the lock-in thermography technique (LIT) to successfully visualize the single-walled carbon nanotube (CNT) networks during the tensile deformation of CNT/fluoro-rubber (FKM) composites. The LIT images revealed that the CNT network modes in CNT/FKM during strain-loading and unloading can be classified into four sites: (i) disconnection, (ii) recovery after disconnection, (iii) undestroyable, and (iv) no network. Quantitative analysis of the heat intensity of the LIT also indicated that the change in resistance during strain-loading and unloading plays a role in the balance of disconnection and reconstruction of the conductive network. We demonstrated the ability of LIT to effectively visualize and quantify the network state of the composite under deformation, and the LIT results were found to be strongly correlated with the composite properties. These results highlighted the potential of LIT as a valuable tool for composite characterization and material design.

Development of a tooth movement model of root resorption during intrusive orthodontic treatment.

There is a high risk of external apical root resorption (EARR) following the application of intrusive orthodontic forces to the apical root. However, there is a lack of suitable animal models to study this phenomenon in depth. This study compared the usability of three different types of loops, namely, vertical helical loop, box loop, and L loop, for preparing a rat model of orthodontic tooth movement with invasive forces. Results showed a significant downward movement in the first molar of the rat after L loop placement for 14 days. Three-dimensional reconstructed images showed root resorption and length shortening on the apical root and decreased bone volume and trabecular thickness in the alveolar bone under compression. Histological staining revealed odontoclasts on the root resorption fossa. This study showed that orthodontic tooth movement using the L loop provides an effective experimental animal model of EARR.

Effects of polyphenols in non-centrifugal cane sugar on saliva secretion: in vitro and in vivo experiments and a randomized controlled trial.

This study examined the bioactivities and mechanisms of the non-centrifugal cane sugar polyphenols saponarin, schaftoside, and isoschaftoside in the salivary gland and their effects on salivation. In acute isolated C57BL/6N mouse submandibular gland cells, these polyphenols led to a higher increase in intracellular calcium after stimulation with the muscarinic agonist carbachol. Stimulation of these cells with polyphenols enhanced ATP production, aquaporin-5 translocation to the plasma membrane and eliminated intracellular reactive oxygen species generated by H2O2. In addition, phosphorylation of endothelial nitric oxide synthase and increased nitric oxide production in vascular endothelial cells were observed. In vivo administration of these polyphenols to C57BL/6N male mice resulted in significantly increased blood flow (saponarin, p = 0.040; isoschaftoside, p = 0.010) and salivation (saponarin, p = 0.031). A randomized controlled trial showed that intake of non-centrifugal cane sugar significantly increased saliva secretion compared with placebo (p = 0.003). These data suggest that non-centrifugal cane sugar polyphenols affect several pathways that support salivation and increase saliva secretion by enhancing vasodilation. Hence, non-centrifugal cane sugar polyphenols can be expected to maintain saliva secretion and improve reduced saliva flow.

Senescence-associated secretory phenotypes in rat-derived dedifferentiated fat cells with replicative senescence.

Senescence-associated secretory phenotype (SASPs) secreted from senescent cells often cause the deleterious damages to the surrounding tissues. Although dedifferentiated fat (DFAT) cells prepared are considered a promising cell source for regenerative therapies, SASPs from DFAT cells undergoing long-term cell culture, which latently induce replicative senescence, have barely been explored. The present study was designed to investigate senescent behaviors in rat-derived DFAT cells at high passage numbers and to analyze the possible types of SASPs. Our data show that DFAT cells undergo senescence during replicative passaging, as determined by multiple senescent hallmarks including morphological changes in cell shape and nucleus. Moreover, RT2 PCR array analysis indicated that senescent DFAT cells expressed higher levels of 16 inflammatory cytokines (Ccl11, Ccl12, Ccl21, Ccl5, Csf2, Cxcl1, Cxcl12, Ifna2, IL11, IL12a, IL13, IL1a, IL1rn, IL6, Mif, and Tnf) associated with SASPs than non-senescent cells. This study implicates that rat DFAT cells undergo cellular senescence after long-term cell culture; cautious consideration should be paid to treat SASP secretion when senescent DFAT cells are used in regenerative medicine.

Identification of Senescent Cells in Peri-Implantitis and Prevention of Mini-Implant Loss Using Senolytics.

Peri-implantitis is a disease that causes the detachment of orthodontic mini-implants. Recently, stress-induced senescent cells have been reported to be involved in various inflammatory diseases. Senescent cell-eliminating drugs, termed "senolytics", can improve the symptoms of such diseases. However, the relationship between peri-implantitis and senescent cells remains unclear. In this study, we evaluated the presence of senescent cells in a rat peri-implantitis model developed with a gum ring. The effect on bone resorption and implant loss was also investigated with and without senolytics (Dasatinib and Quercetin). The number of senescence markers (p19, p21, and p16) was found to increase, and implant detachment occurred in 24 days. After the administration of senolytics, the number of senescence markers decreased and implant detachment was inhibited. This study suggests that senescent cells aggravate peri-implantitis and senolytic administration latently reduces implant loss by inhibiting senescence-related mechanisms.

Lignocellulose molecular assembly and deconstruction properties of lignin-altered rice mutants.

Bioengineering approaches to modify lignin content and structure in plant cell walls have shown promise for facilitating biochemical conversions of lignocellulosic biomass into valuable chemicals. Despite numerous research efforts, however, the effect of altered lignin chemistry on the supramolecular assembly of lignocellulose and consequently its deconstruction in lignin-modified transgenic and mutant plants is not fully understood. In this study, we aimed to close this gap by analyzing lignin-modified rice (Oryza sativa L.) mutants deficient in 5-HYDROXYCONIFERALDEHYDE O-METHYLTRANSFERASE (CAldOMT) and CINNAMYL ALCOHOL DEHYDROGENASE (CAD). A set of rice mutants harboring knockout mutations in either or both OsCAldOMT1 and OsCAD2 was generated in part by genome editing and subjected to comparative cell wall chemical and supramolecular structure analyses. In line with the proposed functions of CAldOMT and CAD in grass lignin biosynthesis, OsCAldOMT1-deficient mutant lines produced altered lignins depleted of syringyl and tricin units and incorporating noncanonical 5-hydroxyguaiacyl units, whereas OsCAD2-deficient mutant lines produced lignins incorporating noncanonical hydroxycinnamaldehyde-derived units. All tested OsCAldOMT1- and OsCAD2-deficient mutants, especially OsCAldOMT1-deficient lines, displayed enhanced cell wall saccharification efficiency. Solid-state nuclear magnetic resonance (NMR) and X-ray diffraction analyses of rice cell walls revealed that both OsCAldOMT1- and OsCAD2 deficiencies contributed to the disruptions of the cellulose crystalline network. Further, OsCAldOMT1 deficiency contributed to the increase of the cellulose molecular mobility more prominently than OsCAD2 deficiency, resulting in apparently more loosened lignocellulose molecular assembly. Such alterations in cell wall chemical and supramolecular structures may in part account for the variations of saccharification performance of the OsCAldOMT1- and OsCAD2-deficient rice mutants.

Cholesterol granuloma in facial nerve canal presenting with facial nerve paralysis.

Cholesterol granulomas (CGs) are frequently found in the temporal bone, but their presence in the facial nerve has not been reported. We report a case of a 58-year-old woman who presented with left facial palsy caused by a CG that appeared to have originated in the facial nerve. Temporal bone computed tomography (CT) revealed soft tissue masses in the left middle ear spaces, and the facial canal was dilated from the genu to the vertical portion. Magnetic resonance imaging (MRI) revealed high signal intensity on T1-weighted images and partially high signal intensity on T2-weighted images, although no significant enhancement was observed on gadolinium-enhanced MRI. Surgical findings revealed CG in the middle ear spaces, but the facial canal remained intact and lacked continuity with the internal mass. Histopathological analysis verified the mass as a CG accompanied by cholesterol crystals. The mass was located within and continuous with the epineurium. These findings indicate that hemorrhage in the facial canal may have triggered the formation of the CG, causing left facial palsy due to increased pressure in the facial canal.

Relationship between intra-individual variability in nutrition-related lifestyle behaviors and blood glucose outcomes under free-living conditions in adults without type 2 diabetes.

AIMS: This study determined the relationship between intra-individual variability in day-to-day nutrition-related lifestyle behaviors (meal timing, eating window, food intake, movement behaviors, sleep conditions, and body weight) and glycemic outcomes under free-living conditions in adults without type 2 diabetes. METHODS: We analyzed 104 adults without type 2 diabetes. During the 7-day measurement period, dietary intake, movement behaviors, sleep conditions, and glucose outcomes were assessed. Daily food intake was assessed using a mobile-based health application. Movement behaviors and sleep conditions were assessed using a tri-axial accelerometer. Meal timing was assessed from the participant's daily life record. Blood glucose levels were measured continuously using a glucose monitor. Statistical analyses were conducted using a linear mixed-effects model, with mealtime, food intake, body weight, movement behaviors, and sleep conditions as fixed effects and participants as a random effect. RESULTS: Dinner time and eating window were positively significantly correlated with mean (dinner time, p = 0.003; eating window, p = 0.001), standard deviation (SD; both at p < 0.001), and maximum (both at p < 0.001) blood glucose levels. Breakfast time was negatively associated with glucose outcomes (p < 0.01). Sedentary time was positively significantly associated with blood glucose SD (p = 0.040). Total sleep time was negatively significantly correlated with SD (p = 0.035) and maximum (p = 0.032) blood glucose levels. Total daily energy intake (p = 0.001), carbohydrate intake (p < 0.001), and body weight (p < 0.05) were positively associated with mean blood glucose levels. CONCLUSION: Intra-individual variations in nutrition-related lifestyle behaviors, especially morning and evening body weight, and food intake, were associated with mean blood glucose levels, and a long sedentary time and total sleep time were associated with glucose variability. Earlier dinner times and shorter eating windows per day resulted in better glucose control.

Long-term Effects of the Use of a Step Count-Specific Smartphone App on Physical Activity and Weight Loss: Randomized Controlled Clinical Trial.

BACKGROUND: Some studies on weight loss promotion using smartphone apps have shown a weight loss effect but not an increase in physical activity. However, the long-term effects of smartphone apps on weight loss and increasing physical activity have not been rigorously examined to date. OBJECTIVE: The aim of this study was to assess whether the use of a smartphone app will increase physical activity and reduce body weight. METHODS: In this parallel randomized clinical trial, participants recruited between April 2018 and June 2019 were randomized in equal proportions to a smartphone app group (n=55) or a control group (n=54). The intention-to-treat approach was used to analyze the data from December 2019 through November 2021. Before the intervention, an hour-long lecture on weight loss instruction and increasing physical activity was conducted once for both groups. Participants in both groups were instructed to weigh themselves immediately after waking up at least once daily from the start of the intervention. Monthly emails were sent advising the participants in both groups on how to lose weight and increase physical activity in order to maintain or increase motivation. Participants in the smartphone app group were instructed to open the app at least once a day to check their step count and rank. The primary outcome was daily accelerometer-measured physical activity (step count) and the secondary outcome was body weight. Since there was a significant difference in the wear time of the accelerometer depending on the intervention period (P<.001), the number of steps and moderate-to-vigorous physical activity were also evaluated per wear time. RESULTS: The mean age of the 109 participants in this study was 47 (SD 8) years. At baseline, the mean daily total steps were 7259 (SD 3256) steps per day for the smartphone app group and 8243 (SD 2815) steps per day for the control group. The difference in the step count per wear time between preintervention and postintervention was significantly different between the app group and the control group (average difference [95% CI], 65 [30 to 101] steps per hour vs -9 [-56 to 39] steps per hour; P=.042). The weight loss was -2.2 kg (SD -3.1%) in the smartphone app group and -2.2 kg (SD -3.1%) in the control group, with no significant difference between the groups. In addition, when divided into weekdays (Monday through Friday) and weekends (Saturday and Sunday), there was a significant interaction between step counts (P=.004) and MVPA (P=.003) during the intervention, with the app group showing higher interaction on weekends than the control group. CONCLUSIONS: In this trial, the group with the smartphone app intervention showed increased physical activity, especially on weekends. However, this increased physical activity did not lead to increased weight loss. TRIAL REGISTRATION: University Hospital Medical Information Network UMIN000033397; https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000037956.