SUMO-specific protease 2 regulates lipid droplet size through ERRα-mediated CIDEA expression in adipocytes.

Lipid droplets are not only lipid storage sites but also are closely related to lipid metabolism. Lipid droplet growth increases lipid storage capacity and suppresses lipolysis via lipase associated with the lipid droplet surface. The cell death-inducing DFF45-like effector (CIDE) family of proteins mediates lipid droplet fusion, which mainly contributes to lipid droplet growth. We previously demonstrated small ubiquitin-like modifier (SUMO)-specific protease 2 (SENP2) plays important roles in lipid metabolism and induction/maintenance of adipogenesis. In this study, we determined whether SENP2 regulates lipid droplet size in adipocytes. Overexpression of SENP2 increased lipid droplet size in differentiated 3T3-L1 adipocytes and facilitated CIDEA transcription. We found SENP2 increased CIDEA expression mainly through desumoylation of estrogen-related receptor α (ERRα), which acted in coordination with peroxisome proliferator-activated receptor γ-coactivator α. In addition, palmitate treatment increased SENP2 and CIDEA mRNA levels. Specific small interfering RNA-mediated knockdown of SENP2, as well as ERRα knockdown, eliminated palmitate-induced CIDEA expression. These results suggest SENP2 enhances CIDEA expression by modulating ERRα when SENP2 is upregulated, such as after palmitate treatment, to increase lipid droplet size in adipocytes.

BNIP3 is essential for mitochondrial bioenergetics during adipocyte remodelling in mice.

AIMS/HYPOTHESIS: Adipose tissue is a highly versatile system in which mitochondria in adipocytes undergo significant changes during active tissue remodelling. BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) is a mitochondrial protein and a known mitochondrial quality regulator. In this study, we investigated the role of BNIP3 in adipocytes, specifically under conditions of peroxisome proliferator-activated receptor-γ (PPARγ)-induced adipose tissue remodelling. METHODS: The expression of BNIP3 was evaluated in 3T3-L1 adipocytes in vitro, C57BL/6 mice fed a high-fat diet and db/db mice in vivo. Mitochondrial bioenergetics was investigated in BNIP3-knockdown adipocytes after rosiglitazone treatment. A putative peroxisome proliferator hormone responsive element (PPRE) was characterised by promoter assay and electrophoretic mobility shift assay (EMSA). RESULTS: The protein BNIP3 was more abundant in brown adipose tissue than white adipose tissue. Furthermore, BNIP3 expression was upregulated by 3T3-L1 pre-adipocyte differentiation, starvation and rosiglitazone treatment. Conversely, BNIP3 expression in adipocytes decreased under various conditions associated with insulin resistance. This downregulation of BNIP3 was restored by rosiglitazone treatment. Knockdown of BNIP3 in adipocytes inhibited rosiglitazone-induced mitochondrial biogenesis and function, partially mediated by the 5' AMP-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor γ, co-activator 1 α (PGC1α) signalling pathway. Rosiglitazone treatment increased the transcription level of Bnip3 in the reporter assay and the presence of the PPRE site in the Bnip3 promoter was demonstrated by EMSA. CONCLUSIONS/INTERPRETATION: The protein BNIP3 contributes to the improvement of mitochondrial bioenergetics that occurs on exposure to rosiglitazone. It may be a novel therapeutic target for restoring mitochondrial dysfunction under insulin-resistant conditions.

Herpesvirus-associated ubiquitin-specific protease (HAUSP) modulates peroxisome proliferator-activated receptor γ (PPARγ) stability through its deubiquitinating activity.

The peroxisome proliferator-activated receptor γ (PPARγ) is a central regulator of adipogenesis and modulates glucose and lipid metabolism. In this study, herpesvirus-associated ubiquitin-specific protease (HAUSP) was isolated as a binding partner of PPARγ. Both endogenous and exogenous PPARγ associated with HAUSP in co-immunoprecipitation analysis. HAUSP, but not the catalytically inactive HAUSP C223S mutant, increased the stability of both endogenous and exogenous PPARγ through its deubiquitinating activity. Site-directed mutagenesis experiments showed that the Lys(462) residue of PPARγ is critical for ubiquitination. HBX 41,108, a specific inhibitor of HAUSP, abolished the increase in PPARγ stability induced by HAUSP. In addition, knockdown of endogenous HAUSP using siRNA decreased PPARγ protein levels. HAUSP enhanced the transcriptional activity of both exogenous and endogenous PPARγ in luciferase activity assays. Quantitative RT-PCR analysis showed that HAUSP increased the transcript levels of PPARγ target genes in HepG2 cells, resulting in the enhanced uptake of glucose and fatty acids, and vice versa, upon siRNA knockdown of HAUSP. In vivo analysis using adenoviruses confirmed that HAUSP, but not the HAUSP C223S mutant, decreased blood glucose and triglyceride levels, which are associated with the increased expression of endogenous PPARγ and lipid accumulation in the liver. Our results demonstrate that the stability and activity of PPARγ are modulated by the deubiquitinating activity of HAUSP, which may be a target for the development of anti-diabetic drugs.

Novel strategy for successful long-term hematopoietic recovery after transplanting a limited number of hematopoietic stem/progenitor cells.

Various investigators have attempted to overcome the shortage of available hematopoietic stem/progenitor cells (HSPCs) by facilitating their engraftment after transplantation. Preconditioning of HSPCs with the granulocyte-derived cationic peptide LL-37 has been suggested as a useful strategy to facilitate engraftment of transplanted cells by enhancing their responsiveness to CXCL12. In this study, we evaluated whether LL-37 preconditioning is acceptable for clinical application. We found that the effect of LL-37 preconditioning was specific to clonogenic cells and was mediated specifically by increased calcium influx with the activation of downstream signaling through mammalian target of rapamycin complex 1 (mTORC1). Because hyperactivation of mTORC1 and the disruption of 5' adenosine monophosphate-activated protein kinase (AMPK) are known to deplete HSPC pools, we compared the repopulation capacity of HSPCs preconditioned with LL-37 and those preconditioned with AMPK activator (AICAR). In vivo competitive repopulation experiments revealed that LL-37 preconditioning impairs long-term repopulation of transplanted HSPCs, suggesting that this strategy might not acceptable for clinical applications in which long-term repopulation capacity is a prerequisite. AICAR preconditioning dramatically enhanced the long-term repopulation of transplanted HSPCs, however. Taken together, these results suggest that future strategies to ensure successful transplantation outcomes should focus on protecting HSPCs from various stimuli during their homing to the bone marrow niches rather than activating them before transplantation.

Simple prediction method of lumbar lordosis for planning of lumbar corrective surgery: radiological analysis in a Korean population.

PURPOSE: This study aimed at deriving a lordosis predictive equation using the pelvic incidence and to establish a simple prediction method of lumbar lordosis for planning lumbar corrective surgery in Asians. METHODS: Eighty-six asymptomatic volunteers were enrolled in the study. The maximal lumbar lordosis (MLL), lower lumbar lordosis (LLL), pelvic incidence (PI), and sacral slope (SS) were measured. The correlations between the parameters were analyzed using Pearson correlation analysis. Predictive equations of lumbar lordosis through simple regression analysis of the parameters and simple predictive values of lumbar lordosis using PI were derived. RESULTS: The PI strongly correlated with the SS (r = 0.78), and a strong correlation was found between the SS and LLL (r = 0.89), and between the SS and MLL (r = 0.83). Based on these correlations, the predictive equations of lumbar lordosis were found (SS = 0.80 + 0.74 PI (r = 0.78, R (2) = 0.61), LLL = 5.20 + 0.87 SS (r = 0.89, R (2) = 0.80), MLL = 17.41 + 0.96 SS (r = 0.83, R (2) = 0.68). When PI was between 30° to 35°, 40° to 50° and 55° to 60°, the equations predicted that MLL would be PI + 10°, PI + 5° and PI, and LLL would be PI - 5°, PI - 10° and PI - 15°, respectively. CONCLUSION: This simple calculation method can provide a more appropriate and simpler prediction of lumbar lordosis for Asian populations. The prediction of lumbar lordosis should be used as a reference for surgeons planning to restore the lumbar lordosis in lumbar corrective surgery.

Analysis of the predictive role and new proposal for surgical strategies based on the modified Tomita and Tokuhashi scoring systems for spinal metastasis.

BACKGROUND: We sought to identify preoperative factors significantly correlated with survival. We also aimed to evaluate the validity of the prognostic scores in the Tomita and Tokuhashi systems and discuss several aspects to improve the predictive accuracy of these systems. Moreover, we suggest modified criteria for selecting treatment strategies. METHODS: In total, the outcomes of 112 patients with spinal metastasis who underwent surgery between January 2006 and June 2011 were retrospectively reviewed. The validity of the prognostic scores was assessed on the basis of their correlation with survival. For various primary malignancies, new scoring criteria were applied in each system according to the survival results obtained in this study. Each revised scoring system was adjusted with a similar principle of scoring as described previously. Patient survival according to each preoperative factor was analyzed by the Kaplan-Meier method. The predictive value of each scoring system was evaluated by the log-rank test and Cox regression analysis. RESULTS: The interval from the diagnosis of the primary malignancy to that of spinal metastasis (p = 0.023) and the interval from the diagnosis of spinal metastasis to surgery (p = 0.039) were significantly correlated with survival. Regarding Tokuhashi scores, the correlation coefficient was 0.790 before adjustment (p = 0.001) and 0.853 after adjustment (p < 0.001). For Tomita scores, the correlation coefficient was -0.994 (p < 0.001) both before and after adjustment. CONCLUSIONS: Tomita scores more accurately predicted survival than Tokuhashi scores. It is helpful to evaluate both scoring systems with adjustment for primary malignancy depending on the clinical setting. Patients with Tomita scores less than or equal to 8 and Tokuhashi scores greater than or equal to 6 are recommended to undergo surgical management.

F-box only protein 9 is required for adipocyte differentiation.

The objective of this study is to investigate whether F-box only protein 9 (FBXO9), an ubiquitination E3 ligase, has a functional role in adipocyte differentiation. Expression of FBXO9 was compared between obese mice and control lean mice using real-time PCR. Also, expression pattern of FBXO9 was monitored during 3T3-L1 adipocyte differentiation. FBXO9 was highly expressed in obese mice, and increased in the early stages of adipogenesis. To verify a functional role of FBXO9 in adipogenesis, FBXO9 was knocked down using transfection of siRNAs against FBXO9 into 3T3-L1 cells during the induction of adipogenesis. Knockdown of FBXO9 in early stage of adipogenesis almost completely inhibited adipogenesis, and CCAAT/enhancer binding protein ß (C/EBPß) levels were significantly reduced. However, the cells stably expressing C/EBPß were fairly differentiated into adipocytes in the FBXO9 knockdown condition. These results suggest that FBXO9 is required for adipocyte differentiation, and C/EBPß plays a role in the effect of FBXO9 on adipogenesis.

SUMO-specific protease SUSP4 positively regulates p53 by promoting Mdm2 self-ubiquitination.

The p53 tumour suppressor has a key role in the control of cell growth and differentiation, and in the maintenance of genome integrity. p53 is kept labile under normal conditions, but in response to stresses, such as DNA damage, it accumulates in the nucleus for induction of cell-cycle arrest, DNA repair or apoptosis. Mdm2 is an ubiquitin ligase that promotes p53 ubiquitination and degradation. Mdm2 is also self-ubiquitinated and degraded. Here, we identified a novel cascade for the increase in p53 level in response to DNA damage. A new SUMO-specific protease, SUSP4, removed SUMO-1 from Mdm2 and this desumoylation led to promotion of Mdm2 self-ubiquitination, resulting in p53 stabilization. Moreover, SUSP4 competed with p53 for binding to Mdm2, also resulting in p53 stabilization. Overexpression of SUSP4 inhibited cell growth, whereas knockdown of susp4 by RNA interference (RNAi) promoted of cell growth. UV damage induced SUSP4 expression, leading to an increase in p53 levels in parallel with a decrease in Mdm2 levels. These findings establish a new mechanism for the elevation of cellular p53 levels in response to UV damage.

The effect of simulated knee flexion on sagittal spinal alignment: novel interpretation of spinopelvic alignment.

INTRODUCTION: Many studies regarding spinal sagittal alignment were focused mainly on above-hip structures, not considering the knee joint. Knee-spine syndrome was proposed earlier, but the mechanism of this phenomenon has not been revealed. The aim of the study was to demonstrate how spinopelvic alignment and sagittal balance change in response to simulated knee flexion in normal non-diseased population. METHODS: Thirty young male were enrolled in the study cohort. Two motion-controlled knee braces were used to simulate knee flexion of 0°, 15°, and 30° settings. Whole spine and lower extremity lateral radiographs were taken at each knee setting of 0°, 15°, and 30° flexion. Spinal and pelvic parameters were measured, including two angular parameters, femoropelvic angle (FPA) and femoral tilt angle (FTA). RESULTS: The following equation can be made; PT (pelvic tilt) = FPA + FTA. The mean values of FPA and lumbar lordosis decreased significantly at 15° and 30° knee settings compared to the parameters at the 0° knee setting, while the mean values of pelvic tilt and sacral slope rarely changed. Results also showed FTA was not correlated with PT, but strongly correlated with FPA (R = -0.83, p < 0.01). CONCLUSIONS: The knee flexion resulted in decrease of lumbar lordosis without a significant change of pelvic posture in non-diseased population group.

Comparison of surgical outcomes after cervical laminoplasty: open-door technique versus French-door technique.

STUDY DESIGN: A retrospective case series. OBJECTIVE: To compare the surgical outcomes of open-door and French-door cervical laminoplasty for decompressing multilevel cervical spinal cord compressions. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty is an effective method for decompressing multilevel cervical spinal cord compressions. Laminoplasty is usually classified as an open-door or French-door technique, but it is still unclear whether laminoplasty affects cervical alignment and clinical outcomes. METHODS: Fifty-one patients underwent cervical laminoplasty over a 2-year period for cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament, or for a mixed-type condition. The following criteria were evaluated and compared retrospectively for open-door laminoplasty (group A) and French-door laminoplasty (group B): Nurick grades, Japanese Orthopedic Association (JOA) scores, neck disability index, and visual analog scale scores for axial neck pain and radiating pain. During radiologic evaluations, changes in cervical lordotic angles and range of motion were measured at C2-C7. RESULTS: Postoperatively, radiating pain improved significantly in both groups (P<0.05), but axial neck pain was more severe in both groups at last follow-up than preoperatively (P>0.05). Mean neurological improvement was 12.5% according to Nurick grades and 28% according to JOA scores in all study subjects. In particular, the mean Nurick grades showed significant improvement in group A (P<0.05), and the recovery rate was higher in group A than in group B according to Nurick grades (23.5% vs. 6.3%; P<0.05) and JOA scores (44.4% vs. 13%; P<0.05). In contrast, radiologically, cervical lordotic angle and range of motion were more significantly decreased in group B (P<0.05). CONCLUSIONS: Although open-door and French-door laminoplasty techniques were found to be effective for treating cervical compressive myelopathy, the open-door technique seems to be superior with respect to clinical and radiologic outcomes.

A comparative study between thoracoscopic surgery and posterior surgery using all-pedicle-screw constructs in the treatment of adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: To present the results of thoracoscopic surgery in the treatment of adolescent idiopathic scoliosis (AIS) and to compare the results of thoracoscopic surgery with those of posterior surgery. SUMMARY OF BACKGROUND DATA: Although racoscopic scoliosis correction has attracted attention since the early 2000s, its use has declined gradually, whereas posterior surgery using pedicle screws has become popular. Few studies have compared thoracoscopic surgery with posterior pedicle screw fixation for single thoracic AIS correction. METHODS: Sixty-five patients with Lenke type-1 AIS were included and followed up for a minimum of 24 months. Forty-two patients underwent thoracoscopic surgery (thoracoscopic group) and 23 patients underwent posterior surgery (posterior group). Radiographic outcomes, including the correction rate and loss of correction, perioperative morbidities, and complications, were compared. RESULTS: Both groups were similar in terms of the preoperative baseline data. Although the correction rate of major thoracic curve was similar, the posterior group had a tendency to have a greater correction rate (72% vs. 66%). A loss of correction was significantly greater in the thoracoscopic group. The thoracoscopic group had a longer operation time and less intraoperative blood loss, with a lower transfusion rate than the posterior group. There was no difference at the last follow-up in terms of pain score and satisfaction. Five implant failures (12%) occurred in the thoracoscopic group and none in the posterior group. There were 3 patients with significant pulmonary complications necessitating active treatments in the thoracoscopic group. CONCLUSIONS: Despite its advantages, thoracoscopic surgery is losing its place in the surgical correction of AIS because of the frequent perioperative pulmonary complications and fixation problems compared with posterior pedicle screw fixation. Nevertheless, it can be utilized in selected cases particularly in cases of patient's strong demand for minimally invasive surgery.

Role of SUMO-Specific Protease 2 in Leptin-Induced Fatty Acid Metabolism in White Adipocytes.

BACKGROUND: Leptin is a 16-kDa fat-derived hormone with a primary role in controlling adipose tissue levels. Leptin increases fatty acid oxidation (FAO) acutely through adenosine monophosphate-activated protein kinase (AMPK) and on delay through the SUMO-specific protease 2 (SENP2)-peroxisome proliferator-activated receptor δ/γ (PPARδ/γ) pathway in skeletal muscle. Leptin also directly increases FAO and decreases lipogenesis in adipocytes; however, the mechanism behind these effects remains unknown. Here, we investigated the role of SENP2 in the regulation of fatty acid metabolism by leptin in adipocytes and white adipose tissues. METHODS: The effects of leptin mediated by SENP2 on fatty acid metabolism were tested by siRNA-mediated knockdown in 3T3-L1 adipocytes. The role of SENP2 was confirmed in vivo using adipocyte-specific Senp2 knockout (Senp2-aKO) mice. We revealed the molecular mechanism involved in the leptin-induced transcriptional regulation of carnitine palmitoyl transferase 1b (Cpt1b) and long-chain acyl-coenzyme A synthetase 1 (Acsl1) using transfection/reporter assays and chromatin immunoprecipitation. RESULTS: SENP2 mediated the increased expression of FAO-associated enzymes, CPT1b and ACSL1, which peaked 24 hours after leptin treatment in adipocytes. In contrast, leptin stimulated FAO through AMPK during the initial several hours after treatment. In white adipose tissues, FAO and mRNA levels of Cpt1b and Acsl1 were increased by 2-fold 24 hours after leptin injection in control mice but not in Senp2-aKO mice. Leptin increased PPARα binding to the Cpt1b and Acsl1 promoters in adipocytes through SENP2. CONCLUSION: These results suggest that the SENP2-PPARα pathway plays an important role in leptin-induced FAO in white adipocytes.

Direct Differentiation of Bone Marrow Mononucleated Cells Into Insulin-Producing Cells Using 4 Specific Soluble Factors.

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.

SUMO modification selectively regulates transcriptional activity of peroxisome-proliferator-activated receptor γ in C2C12 myotubes.

PPAR (peroxisome-proliferator-activated receptor) γ, a nuclear receptor, can be conjugated with SUMO (small ubiquitin-like modifier), which results in the negative regulation of its transcriptional activity. In the present study, we tested whether de-SUMOylation of PPARγ affects the expression of PPARγ target genes in mouse muscle cells and investigated the mechanism by which de-SUMOylation increases PPARγ transcriptional activity. We found that the SUMO-specific protease SENP2 [SUMO1/sentrin/SMT3 (suppressor of mif two 3 homologue 1)-specific peptidase 2] effectively de-SUMOylates PPARγ-SUMO conjugates. Overexpression of SENP2 in C2C12 cells increased the expression of some PPARγ target genes, such as FABP3 (fatty-acid-binding protein 3) and CD36 (fatty acid translocase), both in the absence and presence of rosiglitazone. In contrast, overexpression of SENP2 did not affect the expression of another PPARγ target gene ADRP (adipose differentiation-related protein). De-SUMOylation of PPARγ increased ChIP (chromatin immunoprecipitation) of both a recombinant PPRE (PPAR-response element) and endogenous PPREs of the target genes CD36 and FABP3, but ChIP of the PPRE in the ADRP promoter was not affected by SENP2 overexpression. In conclusion, these results indicate that SENP2 de-SUMOylates PPARγ in myotubes, and de-SUMOylation of PPARγ selectively increases the expression of some PPARγ target genes.

SENP2 regulates mitochondrial function and insulin secretion in pancreatic ß cells.

Increasing evidence has shown that small ubiquitin-like modifier (SUMO) modification plays an important role in metabolic regulation. We previously demonstrated that SUMO-specific protease 2 (SENP2) is involved in lipid metabolism in skeletal muscle and adipogenesis. In this study, we investigated the function of SENP2 in pancreatic ß cells by generating a ß cell-specific knockout (Senp2-ßKO) mouse model. Glucose tolerance and insulin secretion were significantly impaired in the Senp2-ßKO mice. In addition, glucose-stimulated insulin secretion (GSIS) was decreased in the islets of the Senp2-ßKO mice without a significant change in insulin synthesis. Furthermore, islets of the Senp2-ßKO mice exhibited enlarged mitochondria and lower oxygen consumption rates, accompanied by lower levels of S616 phosphorylated DRP1 (an active form of DRP1), a mitochondrial fission protein. Using a cell culture system of NIT-1, an islet ß cell line, we found that increased SUMO2/3 conjugation to DRP1 due to SENP2 deficiency suppresses the phosphorylation of DRP1, which possibly induces mitochondrial dysfunction. In addition, SENP2 overexpression restored GSIS impairment induced by DRP1 knockdown and increased DRP1 phosphorylation. Furthermore, palmitate treatment decreased phosphorylated DRP1 and GSIS in ß cells, which was rescued by SENP2 overexpression. These results suggest that SENP2 regulates mitochondrial function and insulin secretion at least in part by modulating the phosphorylation of DRP1 in pancreatic ß cells.

SENP2 suppresses browning of white adipose tissues by de-conjugating SUMO from C/EBPß.

The adipose tissue is a key site regulating energy metabolism. One of the contributing factors behind this is browning of white adipose tissue (WAT). However, knowledge of the intracellular determinants of the browning process remains incomplete. By generating adipocyte-specific Senp2 knockout (Senp2-aKO) mice, here we show that SENP2 negatively regulates browning by de-conjugating small ubiquitin-like modifiers from C/EBPß. Senp2-aKO mice are resistant to diet-induced obesity due to increased energy expenditure and heat production. Senp2 knockout promotes beige adipocyte accumulation in inguinal WAT by upregulation of thermogenic gene expression. In addition, SENP2 knockdown promotes thermogenic adipocyte differentiation of precursor cells isolated from inguinal and epididymal WATs. Mechanistically, sumoylated C/EBPß, a target of SENP2, suppresses expression of HOXC10, a browning inhibitor, by recruiting a transcriptional repressor DAXX. These findings indicate that a SENP2-C/EBPß-HOXC10 axis operates for the control of beige adipogenesis in inguinal WAT.

Mechanism for antioxidative effects of thiazolidinediones in pancreatic ß-cells.

Thiazolidinediones (TZDs) are synthetic ligands of peroxisome proliferator-activated receptor-γ (PPARγ), a member of the nuclear receptor superfamily. TZDs are known to increase insulin sensitivity and also to have an antioxidative effect. In this study, we tested whether TZDs protect pancreatic ß-cells from oxidative stress, and we investigated the mechanism involved in this process. To generate oxidative stress in pancreatic ß-cells (INS-1 and ßTC3) or isolated islets, glucose oxidase was added to the media. The extracellular and intracellular reactive oxygen species (ROS) were measured to directly determine the antioxidant effect of TZDs. The phosphorylation of JNK/MAPK after oxidative stress was detected by Western blot analysis, and glucose-stimulated insulin secretion and cell viability were also measured. TZDs significantly reduced the ROS levels that were increased by glucose oxidase, and they effectively prevented ß-cell dysfunction. The antioxidative effect of TZDs was abolished in the presence of a PPARγ antagonist, GW9662. Real-time PCR was used to investigate the expression levels of antioxidant genes. The expression of catalase, an antioxidant enzyme, was increased by TZDs in pancreatic ß-cells, and the knockdown of catalase significantly inhibited the antioxidant effect of TZDs. These results suggest that TZDs effectively protect pancreatic ß-cells from oxidative stress, and this effect is dependent largely on PPARγ. In addition, the expression of catalase is increased by TZDs, and catalase, at least in part, mediates the antioxidant effect of TZDs in pancreatic ß-cells.

The impact of sagittal balance on clinical results after posterior interbody fusion for patients with degenerative spondylolisthesis: a pilot study.

BACKGROUND: Comparatively little is known about the relation between the sagittal vertical axis and clinical outcome in cases of degenerative lumbar spondylolisthesis. The objective of this study was to determine whether lumbar sagittal balance affects clinical outcomes after posterior interbody fusion. This series suggests that consideration of sagittal balance during posterior interbody fusion for degenerative spondylolisthesis can yield high levels of patient satisfaction and restore spinal balance METHODS: A retrospective study of clinical outcomes and a radiological review was performed on 18 patients with one or two level degenerative spondylolisthesis. Patients were divided into two groups: the patients without improvement in pelvic tilt, postoperatively (Group A; n=10) and the patients with improvement in pelvic tilt postoperatively (Group B; n=8). Pre- and postoperative clinical outcome surveys were administered to determine Visual Analogue Pain Scores (VAS) and Oswestry disability index (ODI). In addition, we evaluated full spine radiographic films for pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), sacrofemoral distance (SFD), and sacro C7 plumb line distance (SC7D) RESULTS: All 18 patients underwent surgery principally for the relief of radicular leg pain and back pain. In groups A and B, mean preoperative VAS were 6.85 and 6.81, respectively, and these improved to 3.20 and 1.63 at last follow-up. Mean preoperative ODI were 43.2 and 50.4, respectively, and these improved to 23.6 and 18.9 at last follow-up. In spinopelvic parameters, no significant difference was found between preoperative and follow up variables except PT in Group A. However, significant difference was found between the preoperative and follows up values of PT, SS, TK, LL, and SFD/SC7D in Group B. Between parameters of group A and B, there is borderline significance on preoperative PT, preoperative LL and last follow up SS.Correlation analysis revealed the VAS improvements in Group A were significantly related to postoperative lumbar lordosis (Pearson's coefficient=-0.829; p=0.003). Similarly, ODI improvements were also associated with postoperative lumbar lordosis (Pearson's coefficient=-0.700; p=0.024). However, in Group B, VAS and ODI improvements were not found to be related to postoperative lumbar lordosis and to spinopelvic parameters. CONCLUSION: In the current series, patients improving PT after fusion were found to achieve good clinical outcomes in degenerative spondylolisthesis. Overall, our findings show that it is important to quantify sagittal spinopelvic parameters and promote sagittal balance when performing lumbar fusion for degenerative spondylolisthesis.

Significance of angular mismatch between vertebral endplate and prosthetic endplate in lumbar total disc replacement.

STUDY DESIGN: A retrospective study. OBJECTIVE: To determine whether angular mismatch between the vertebral endplate and prosthetic endplate during lumbar total disc replacement (L-TDR) affects the radiological and clinical outcomes. SUMMARY OF BACKGROUND DATA: A prosthesis anchored to the vertebral body by using a large central keel carries an inherent risk of angular mismatch between the vertebral endplate and prosthetic endplate at a segment with a greater degree of lordosis, such as L5-S1. Theoretically, this angular mismatch can cause several problems, such as segmental hyperlordosis, anterior positioning of the upper prosthesis, posterior prosthetic edge subsidence, decreased range of motion (ROM), and a poor clinical outcome. METHODS: This study evaluated 64 prosthetic levels of 56 patients who were implanted with L-TDR between June 2002 and February 2006. There were 38 and 26 prosthetic levels at the L4-5 and L5-S1, respectively. The mean follow-up period was 25.6 (12 to 49) months. The angle of mismatch between the lower endplate of the upper vertebral body and the upper prosthetic plate, segmental flexion/extension ROM, segmental lordosis angle at extension, distance from the posterior wall of the vertebral body to the posterior prosthetic edge were measured by obtaining radiographs. Clinically, the Visual Analogue Scale and Oswestry Disability Index were also evaluated. RESULTS: The angular mismatches between the upper vertebra and prosthesis at L4-5 and L5-S1 were 1.6 degree and 5.6 degree, respectively (P <0.001), at the final follow-up; these angles were not significantly different from those measured on radiographs obtained postoperatively (2.3 degree and 4.9 degree in L4-5 and L5-S1, respectively, P=0.324 in L4-5 and P=0.620 in L5-S1). The mean segmental ROM of the operated levels was 10.6 degree (4 to 22) and 6.1 degree (2 to 13) in the L4-5 and L5-S1, respectively (P <0.001). The mean segmental ROM, mean segmental lordosis angle, and mean distance from the posterior margin of the vertebral body to the posterior edge of the prosthesis in L5-S1 were 6.8 degree (4 to 13), 12.8 degree (8 to 17), and 3.8 mm (1 to 6 mm) in patients with an angular mismatch of <10 degree, and were 4.6 degree (2 to 7), 21.3 degree (19 to 25), and 6.0 mm (2 to 8 mm) in patients with an angular mismatch of more than 10 degree (P=0.024, <0.001, and 0.039), respectively. In L4-5, there were only 2 cases with an angular mismatch of more than 5 degree, which had no statistical significance. There were no significant differences in the clinical outcomes, Visual Analogue Scale, and Oswestry Disability Index between patients with an angular mismatch of <10 degree and those with an angular mismatch of more than 10 degree (P >0.05). CONCLUSIONS: Angular mismatch was more common in L5-S1 than in L4-5. L-TDR at the most lordotic level, L5-S1, and implantation of an upper prosthesis with a mismatched angle seem to be the causes of a reduced segmental ROM, increased segmental lordosis, and anterior malpositioning of the prosthesis. However, these changes do not affect the clinical outcomes of patients.

Changes of upper thoracic curve and shoulder balance in thoracic adolescent idiopathic scoliosis treated by anterior selective thoracic fusion using VATS.

STUDY DESIGN: A retrospective radiographic analysis. OBJECTIVES: To evaluate changes of upper thoracic curve and shoulder balance in thoracic adolescent idiopathic scoliosis patients treated by anterior selective thoracic fusion using video-assisted thoracoscopic surgery and to identify adequacy of earlier criteria of double thoracic (DT) curve for anterior correction. SUMMARY OF BACKGROUND DATA: Although anterior and posterior scoliosis correction show many differences in correction mechanisms, fusion levels, loss of correction etc., the criteria of DT curve was applied without differences. There are no reports about these differences. MATERIALS AND METHODS: Forty patients were followed for a minimum of 3 years (range, 3-8 y). The magnitude and flexibility of upper thoracic, lower thoracic, and the superior portion of the lower thoracic curve were measured using full length standing and side-bending radiographs before surgery, at 1 week postoperatively, and at last follow-up. The correction rate and loss of correction of these curves were calculated and preoperative and postoperative radiographic shoulder heights (RSHs) were measured. RSH was defined as balanced (shoulder height difference <10 mm), mildly imbalanced (10-20 mm), or moderately imbalanced (>20 mm). T1 tilt and coronal balance were also evaluated. Patients were divided into groups based on these factors and postoperative RSH was compared. RESULTS: Flexibility of the upper thoracic curve was 46% and magnitude of the upper thoracic curve was corrected spontaneously from 28.6±7.8 degrees to 17.9±7.0 degrees with a 37.4% correction rate that did not change during follow-up. On average, preoperative left shoulder was 6.3±10.5 mm lower than right shoulder and this changed to 10.4±11.8 mm and 6.0±8.2 mm higher than right shoulder at 1 week postoperatively and at last follow-up, respectively. The group with an upper thoracic curve of ≥30 degrees or a superior portion of the lower thoracic curve of ≥30 degrees preoperatively had a higher left shoulder postoperatively (P=0.016, 0.040). Of the 12 patients with a symmetric or higher left shoulder (≥0 mm) preoperatively, 9 patients had a balanced shoulder (-10-10 mm) and 3 patients showed mild shoulder imbalance (<20 mm) at last follow-up. CONCLUSIONS: Among patients who have DT curve, patients with mild left shoulder elevation (<20 mm) can be treated by anterior correction unless the magnitude of upper thoracic curve or superior portion of lower thoracic curve are ≥30 degrees. For anterior correction, criteria of DT curve might be applied less strictly.