Mitochondrial SIRT3 as a protective factor against cyclosporine A-induced nephrotoxicity.

Sirtuin3 (SIRT3), a mitochondrial deacetylase, has been shown to be involved in various kidney diseases. In this study, we aimed to clarify the role of SIRT3 in cyclosporine-induced nephrotoxicity and the associated mitochondrial dysfunction. Madin-Darby canine kidney (MDCK) cells were transfected with Flag-tagged SIRT3 for SIRT3 overexpression or SIRT3 siRNA for the inhibition of SIRT3. Subsequently, the cells were treated with cyclosporine A (CsA) or vehicle. Wild-type and SIRT3 knockout (KO) mice were randomly assigned to receive cyclosporine A or olive oil. Furthermore, SIRT3 activator, honokiol, was treated alongside CsA to wild type mice. Our results revealed that CsA treatment inhibited mitochondrial SIRT3 expression in MDCK cells. Inhibition of SIRT3 through siRNA transfection exacerbated apoptosis, impaired the expression of the AMP-activated protein kinase-peroxisome proliferator-activated receptor gamma coactivator 1 alpha (AMPK-PGC1α) pathway, and worsened mitochondrial dysfunction induced by CsA treatment. Conversely, overexpression of SIRT3 through Flag-tagged SIRT3 transfection ameliorated apoptosis, increased the expression of mitochondrial superoxide dismutase 2, and restored the mitochondrial regulator pathway, AMPK-PGC1α. In SIRT3 KO mice, CsA treatment led to aggravated kidney dysfunction, increased kidney tubular injury, and accumulation of oxidative end products indicative of oxidative stress injury. Meanwhile, SIRT3 activation in vivo significantly mitigated these adverse effects, improving kidney function, reducing oxidative stress markers, and enhancing mitochondrial health following CsA treatment. Overall, our findings suggest that SIRT3 plays a protective role in alleviating mitochondrial dysfunction caused by CsA through the activation of the AMPK-PGC1α pathway, thereby preventing further kidney injury.

Effectiveness of remote monitoring and feedback on objective compliance with a mandibular advancement device for treatment of obstructive sleep apnea.

Compliance with a mandibular advancement device is important for the optimal treatment of obstructive sleep apnea. Recent advances in information and communication technology-based monitoring and intervention for chronic diseases have enabled continuous monitoring and personalized management. Self-evaluation and self-regulation through objective monitoring and feedback may improve compliance. The aim of this study was to evaluate the effects of information and communication technology-based remote monitoring and feedback services, using a smartphone application, on the objective compliance with a mandibular advancement device in patients with obstructive sleep apnea. Forty individuals who were diagnosed with obstructive sleep apnea by polysomnography were randomly assigned to groups A and B. During an initial 6-week evaluation period, the mandibular advancement device-wearing time was monitored with the smartphone application in group B, but not in group A. The two groups then switched the monitoring procedures during the second 6-week period (the smartphone application was then used by group B, but not by group A). If no input data were indicated on the cloud server of the smartphone application during the monitored period, push notifications were provided twice daily. Objective compliance, monitored by a micro-recorder within the mandibular advancement device, was noted and compared based on whether the monitoring service was provided. The number of mandibular advancement device-wearing days was significantly higher in the monitored period than in the unmonitored period. The mandibular advancement device-wearing time did not differ significantly between the two groups. In conclusion, information and communication technology-based remote monitoring and feedback services demonstrated a potential to increase the objective measures of compliance with mandibular advancement devices.

Evaluation of the adaptation of complete denture metal bases fabricated with dental CAD-CAM systems: An in vitro study.

STATEMENT OF PROBLEM: Conventional fabrication of complete denture metal bases is being replaced by the computer-aided design and computer-aided manufacturing (CAD-CAM) systems. However, a comparative analysis of subtractive and additive CAD-CAM manufacturing techniques is lacking. PURPOSE: The purpose of this in vitro study was to compare the adaptation of complete denture metal bases fabricated by milling (subtractive manufacturing) and stereolithography apparatus (SLA) and digital light processing (DLP) (additive manufacturing). MATERIAL AND METHODS: Thirty metal bases were manufactured by using the milling (MIL group), SLA (SLA group), and DLP (DLP group) techniques. The silicone replica technique was used to evaluate the adaptation of the complete denture metal bases, and 30 silicone blocks were fabricated. The silicone block was cut equally in the canine, first molar, and second molar areas. The gap between the model and the metal base was measured by using a digital microscope at the 3 locations, and the measured data were statistically analyzed by using a statistical software program (α=.05). RESULTS: The gaps measured at the 3 areas showed significant differences in all 3 groups (P<.05). At the anterior, middle, and posterior areas, the SLA group showed the narrowest gap (302 ±31 µm, 241 ±39 µm, 201 ±43 µm, respectively). The SLA group also had the narrowest total gap of the metal bases (218 ±33 µm). CONCLUSIONS: The adaptation of the fabricated metal bases varied significantly across the techniques used but fell within a clinically allowable range. The SLA group was the most precise in the fabrication of complete denture metal bases. Further studies are required to analyze the effects of the layer thickness setting, wax elimination, and casting temperature on the adaptation of metal bases manufactured by using SLA.

Evaluation of the accuracy (trueness and precision) of a maxillary trial denture according to the layer thickness: An in vitro study.

STATEMENT OF PROBLEM: Layer thickness in additive manufacturing has stair-step effects that greatly affect the accuracy of the definitive prosthesis. Although the layer thickness can be set, insufficient data comparing and analyzing the accuracy of the fabricated prosthesis after adjusting the layer thickness are available. PURPOSE: The purpose of this in vitro study was to evaluate and compare the accuracy of trial dentures fabricated with different layer thicknesses by using stereolithography (SLA) apparatus. MATERIAL AND METHODS: A maxillary complete edentulous cast was duplicated with silicone material to make a master gypsum cast which was scanned by using a laboratory scanner and saved as a standard tessellation language (STL) file. This was exported into a computer-aided design software program to produce and store the trial denture. Twenty dentures were fabricated according to the set layer thicknesses (50 µm and 100 µm) by using the SLA. The trueness was measured by scanning the intaglio and cameo surfaces to find the best overlap with the reference model to obtain the root mean square value. The precision was evaluated based on the RMS value gained by superimposing the identical scan data from each group and using the combination formula. The Mann-Whitney U-test was used to confirm significant differences among the groups (α=.05). RESULTS: The trueness of the 50-µm-SLA trial denture and the 100-µm-SLA trial denture was significantly different for the intaglio and cameo surfaces (P<.05). However, the intaglio surface did not show a statistically significant difference (P=.987) for precision, but the cameo surface did (P<.05). CONCLUSIONS: It is clinically more appropriate to set the layer thickness to 100 µm rather than 50 µm for the fabrication of accurate trial dentures by using SLA.

Registration of digital dental models and cone-beam computed tomography images using 3-dimensional planning software: Comparison of the accuracy according to scanning methods and software.

INTRODUCTION: The registration of cone-beam computed tomography (CBCT) images and digital dental models is required for the design and manufacturing of dental devices such as implant guides and surgical wafers. This study aims to register intraoral scan (IS) models and cast scan (CS) models onto CBCT images using 3-dimensional (3D) planning software and evaluate the registration accuracy according to scanning methods and 3D planning software. METHODS: The CBCT image of an artificial skull model with reference markers was taken. The CS model and the IS model were obtained from the same skull model, registered onto the CBCT image using 3D planning software packages providing manual registration (MR) function and point-based registration (PR) functions, and set as the experimental groups. After registration, shell to shell deviations and positional differences between the reference model and the experimental models were evaluated. RESULTS: The shell to shell deviations ranged from 0.03 to 0.18 mm. Deviations in both the maxilla and mandible were significantly different according to scanning methods and software packages. In the anteroposterior direction, the IS-MR and CS-MR groups showed significantly different positions. In the superoinferior direction, the MR and PR groups showed significantly different positions. CONCLUSIONS: The registration using the PR function of the 3D planning software packages was significantly more accurate than the registration using the MR function. There was no significant difference between the registrations using the IS model and the CS model when using the PR functions.

The role of nuclear factor erythroid-2-related factor 2 expression in radiocontrast-induced nephropathy.

Radiocontrast-induced nephropathy (CIN) is the third most common cause of acute renal failure. The pathophysiology of CIN is related to tubular injury caused by oxidative stress, and nuclear factor erythroid-2-related factor 2 (Nrf2) is critical in coordinating intracellular antioxidative processes. We thus investigated the role of Nrf2 in CIN. CIN was established in mice and in NRK-52E cells via iohexol administration according to the protocols of previous studies. To determine the role of Nrf2 in CIN, Nrf2 expression was reduced in vivo using Nrf2 knockout (KO) mice (B6.129 × 1-Nfe2 l2tm1Ywk/J) and in vitro with siRNA treatment targeting Nrf2. Increased Nrf2 expression was observed after iohexol treatment both in vivo and in vitro. Serum creatinine at 24 h after iohexol injection was significantly higher in KO mice than in wild-type (WT) mice. Histologic examination showed that iohexol-induced tubular vacuolization and structural disruption were aggravated in Nrf2 KO mice. Significant increases in apoptosis and F4/80(+) inflammatory cell infiltration were demonstrated in KO mice compared to WT mice. In addition, the increase in reactive oxygen species after iohexol treatment was augmented by Nrf2 inhibition both in vivo and in vitro. Nrf2 may be implicated in the pathogenesis of CIN via the modulation of antioxidant, anti-apoptotic, and anti-inflammatory processes.

Resveratrol Ameliorates Contrast Induced Nephropathy Through the Activation of SIRT1-PGC-1α-Foxo1 Signaling in Mice.

BACKGROUND/AIMS: SIRT1 activation promotes the resistance of renal tubular cells to oxidative stress, and resveratrol is known as a SIRT1 activator. METHODS: Resveratrol was injected intraperitoneally with iohexol for 24 hours. NRK-52E cells were pretreated with resveratrol for 24 hours and then exposed to iohexol for 3 hours. Renal function was measured by serum creatinine and cell survival was assessed by MTT assay. We investigated whether resveratrol attenuates oxidative stress and apoptosis in contrast-induced nephropathy (CIN). RESULTS: Serum creatinine and tubular injury increased significantly after iohexol treatment, and resveratrol co-treatment attenuated the renal injury. Cell survival decreased after iohexol exposure and resveratrol reduced cell death induced by iohexol. Resveratrol was accompanied with the activation of SIRT1 and PGC-1α and dephosphorylation of FoxO1 in mice with CIN. SIRT1 and PGC-1α expression were decreased by iohexol, and increased significantly in resveratrol-pretreated cells. These processes resulted in reduction of oxidative stress and apoptosis both in vivo and in vitro experiments. Resveratrol decreased inflammatory cell infiltration induced by iohexol in mice with CIN. SIRT1 inhibition using siRNA in tubular cells accentuated the decrease of cell viability by iohexol. CONCLUSION: Resveratrol attenuated CIN by modulating renal oxidative stress and apoptosis through activation of SIRT1-PGC-1α-FoxO1 signaling.

Evaluation of the marginal and internal gaps of three different dental prostheses: comparison of the silicone replica technique and three-dimensional superimposition analysis.

PURPOSE: The purposes of this study were to evaluate the marginal and internal gaps, and the potential clinical applications of three different methods of dental prostheses fabrication, and to compare the prostheses prepared using the silicone replica technique (SRT) and those prepared using the three-dimensional superimposition analysis (3DSA). MATERIALS AND METHODS: Five Pekkton, lithium disilicate, and zirconia crowns were each manufactured and tested using both the SRT and the two-dimensional section of the 3DSA. The data were analyzed with the nonparametric version of a two-way analysis of variance using rank-transformed values and the Tukey's post-hoc test (α = .05). RESULTS: Significant differences were observed between the fabrication methods in the marginal gap (P < .010), deep chamfer (P < .001), axial wall (P < .001), and occlusal area (P < .001). A significant difference in the occlusal area was found between the two measurement methods (P < .030), whereas no significant differences were found in the marginal gap (P > .350), deep chamfer (P > .719), and axial wall (P > .150). As the 3DSA method is three-dimensional, it allows for the measurement of arbitrary points. CONCLUSION: All of the three fabrication methods are valid for measuring clinical objectives because they produced prostheses within the clinically acceptable range. Furthermore, a three-dimensional superimposition analysis verification method such as the silicone replica technique is also applicable in clinical settings.

Three-dimensional analysis of marginal and internal fit of copings fabricated with polyetherketoneketone (PEKK) and zirconia.

PURPOSE: The purpose of this in vitro study was to compare and analyze the three-dimensional marginal and internal fit of PEKK and zirconia copings. METHODS: Two acrylic models of the right maxillary canine, first molar were fabricated as master dies and duplicated by one-step dual viscosity impressions. Five stone replicas from each model were digitized with a blue-light scanner and copings were machined from Pekkton and Zirconia blanks. The inner surface of all the copings and two original acrylic models were digitized by a highly accurate optical scanner. By superimposing the digitized coping data with the CAD-reference die three-dimensionally, visual fit-discrepancies were drawn by calculating the root mean square (RMS) and visualized on a color-difference map. Each calculated RMS-value was statistically analyzed by 3-way ANOVA. In addition, Student's t-test was conducted in order to verify the significance (α=.05) of fit-discrepancies based on the type of abutment tooth and the materials. RESULTS: Mean RMS-values for marginal fit (internal fit) ranged from 51.64±1.5 (36.12±1.34) to 69.62±8.11 (41.6±1.63)µm. Differences in marginal fit (canine: P=.001; molar: P=.047) and internal fit (canine: P=.017; molar: P=.046) were statistically significant. The results of the 3-way ANOVA showed statistically significant differences in the RMS values of the two groups for the material (P<.001), the types of the abutment tooth (P<.001), and the measured region (P<.001). CONCLUSIONS: The marginal and internal fit of both PEKK and zirconia copings of both canine and molar were within the clinically acceptable range. However, the PEKK presented better fitness compared with the zirconia.

In vitro assessment of the marginal and internal fits of interim implant restorations fabricated with different methods.

STATEMENT OF PROBLEM: The fit of an interim implant restoration (IIR) is important for the effective treatment of patients with partial edentulism. However, no clinical trials have evaluated the marginal and internal fittings achieved with various fabrication methods. PURPOSE: The purpose of this in vitro study was to evaluate and compare the marginal and internal discrepancies in IIRs produced with 3 different methods. MATERIAL AND METHODS: Partially edentulous maxillary and mandibular casts from a transfer abutment were used. Prostheses were prepared by applying wax to the implant abutment. Shapes were copied using putty. IIRs were fabricated from poly(methyl methacrylate) for a conventional system with thermoplastic resin (CTR, n=40), a 4-axial milling machine with a crown-designed standard template library for a subtractive manufacturing system with Pekkton milling (SPM, n=40), and a 3-dimensional printer for an additive manufacturing system with digital light processing (ADL, n=40). The marginal and internal discrepancies were evaluated in each group using the silicone replica technique. The space between the abutment and the intaglio surface of the prosthesis was evaluated with a digital microscope (×160 magnification). Results were analyzed with nonparametric 2-way analysis of variance using rank-transformed values and Tukey post hoc test (α=.05). RESULTS: The fabricated IIRs were significantly different at all points (P<.001). Moreover, ADL was superior to CTR and SPM. IIRs were significantly different only at the intermarginal discrepancy (the vertical discrepancy between the crown and the point where the margin becomes round and changes to the axial wall), the axiogingival discrepancy (the vertical discrepancy between the internal surface and the axial wall adjacent to the gingival wall of the abutment), and the occlusal discrepancy (the vertical discrepancy between the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P<.001). No significant differences were found among the IIRs at the marginal discrepancy (the vertical discrepancy between the abutment margin and the crown; P>.111) and the axio-occlusal discrepancy (the vertical discrepancy between the axial wall adjacent to the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P>.257). CONCLUSIONS: ADL was superior to the other 2 fabrication methods. However, all 3 methods were suitable because they produced a marginal fit which was within the clinically acceptable range.

Translucency of zirconia-based pressable ceramics with different core and veneer thicknesses.

STATEMENT OF PROBLEM: Little information is available on the translucency of zirconia-based pressable ceramic restorations with a pressed ceramic veneer and zirconia core in various thickness combinations. PURPOSE: The purpose of this in vitro study was to assess the translucency of 3 types of zirconia-based pressable ceramics for different core-veneer thickness combinations. MATERIAL AND METHODS: A bilayered ceramic specimen was prepared with a pressable ceramic (IPS e.max Zirpress, Initial IQ, Rosetta UltraPress) veneer over a zirconia core (Zenostar Zr). Three groups of specimens (n=7) were formed with the following core+veneer thicknesses: 1 +0.5 mm, 0.7 +0.8 mm, and 0.5 +1 mm. To obtain consistent thickness and high translucency, all specimens were subjected to surface grinding with a grinding machine. To eliminate the effect of differences in roughness on the translucency, the surface roughness of the ground specimens was measured with a scanning profiler, and the consistency of these measured values was verified through statistical analysis. The luminous transmittance of the specimens was measured with a spectrophotometer. The effects of the pressable ceramic type and core-veneer thickness combination on transmittance were assessed using a 2-way ANOVA (α=.05). RESULTS: The consistency of the surface roughness among the tested specimens was confirmed using a 1-way ANOVA and the Tukey HSD post hoc test (P<.05). The luminous transmittance exhibited a statistically significant dependence on both the type of pressable ceramic and the core-veneer thickness combination (P<.05). CONCLUSIONS: The type of pressable ceramic and core-veneer thickness combination affected the translucency of the restoration.

Radiocontrast-induced nephropathy is attenuated by autophagy through regulation of apoptosis and inflammation.

Radiocontrast-induced nephropathy (RCN) is the third most common cause of acute renal failure among inpatients. Although the number of patients undergoing exams using radiocontrast is increasing, little progress has been made for RCN treatment. The pathophysiology of RCN is known as tubular injury due to oxidative stress. As autophagy regulates cellular damage under stressful conditions, we investigated the role of autophagy in RCN. RCN was induced in male C57BL/6 J mice by intraperitoneal injection of iohexol, and 3-methyladenine (3-MA) was used as an autophagy inhibitor. Tubular injury caused by iohexol was also examined in vitro using rat tubular cells (NRK-52E). Increased autophagy after iohexol administration was demonstrated by the increase of light chain 3-II in the damaged kidney tubules both in vivo and in vitro. Serum creatinine and tubular injury were significantly increased at 24 h after iohexol treatment, as compared to control group. Further they worsened with autophagy inhibition by 3-MA. In vitro studies also demonstrated that decreased cell viability by iohexol was aggravated with 3-MA pretreatment. Malondialdehyde measured for oxidative stress was increased by iohexol, and it was accentuated by autophagy inhibition, which resulted in increase of cytochrome c Apoptosis, increased by iohexol treatment, was augmented with autophagy inhibition. Macrophage infiltration and increase of monocyte chemotactic protein-1 in kidneys were induced by iohexol, and it was aggravated with autophagy inhibition. This study showed that autophagy was involved with the pathophysiology of RCN, and the role of autophagy in modulation of apoptosis, oxidative stress, and inflammatory cell infiltration was supposed as mechanisms mitigating RCN.