Long-term oncological outcomes of robotic versus laparoscopic approaches for right colon cancer: a systematic review and meta-analysis

PURPOSE

The short-term outcomes of robotic right hemicolectomy for right colon cancer have been extensively studied in comparison to conventional laparoscopic right hemicolectomy. However, the long-term oncological outcomes of the two approaches have not been investigated, except in single-center retrospective studies. Therefore, this meta-analysis aimed to investigate the long-term oncological outcomes of robotic right hemicolectomy compared with those of laparoscopic right hemicolectomy for right colon cancer.

METHODS

We searched PubMed, EMBASE, and Cochrane Library for studies comparing robotic right hemicolectomy with conventional laparoscopic right hemicolectomy for right colon cancer from the date of database inception to August 2022. For survival data extraction, hazard ratios (HRs) with 95% confidence intervals (CI) were calculated using random- or fixed-effects models from the Kaplan-Meier survival curves in the included studies. All calculations and statistical tests were performed using Review Manager software, version 5.4.

RESULTS

A total of 523 patients (robotic right hemicolectomy, 230; laparoscopic right hemicolectomy, 293) from five studies were included in this meta-analysis. There were no significant differences in patient characteristics between the two groups. In terms of pathological characteristics, TNM stage was not different and revealed no differences in the number of harvested lymph nodes even though a larger number of lymph nodes were harvested in the robotic group in one study. Pooled analyses demonstrated no significant difference in disease-free survival (HR 0.72, 95% CI 0.46-1.13, p = 0.15) and overall survival (HR 0.73, 95% CI 0.48-1.13, p = 0.16) between robotic and laparoscopic right hemicolectomy for right colon cancer.

CONCLUSION

Robotic right hemicolectomy for right colon cancer is comparable with conventional laparoscopic right hemicolectomy in terms of long-term oncological survival. More prospective, multicenter, randomized trials are necessary to determine the oncologic safety of robotic right hemicolectomy.

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.

Single-incision robotic colorectal surgery with the da Vinci SP® surgical system: initial results of 50 cases

PURPOSE

The da Vinci SP® (dVSP) surgical system (Intuitive Surgical, Sunnyvale, CA, USA), a robotic platform designed for single-incision surgery, overcame the need for multiple ports in traditional robotic surgery and issues including triangulation and retraction in single-incision laparoscopic surgery. However, previous studies only included case reports or series with small sample sizes. The aim of this study was to assess the safety and performance of the dVSP surgical system and its instruments and accessories for colorectal procedures.

METHODS

The medical records of patients who had surgery with the dVSP from March 2019 to September 2021 at Ewha Womans University Seoul Hospital were investigated. The pathologic and follow-up data of patients who had malignant tumors were analyzed separately to evaluate oncological safety.

RESULTS

Fifty patients (26 male and 24 female) with a median age of 59 years (interquartile range 52.5-63.0 years) were enrolled. The procedures included low anterior resection with total mesorectal excision (n = 16), sigmoid colectomy with complete mesocolic excision and central vessel ligation (CME + CVL) (n = 14), right colectomy with CME + CVL (n = 9), left colectomy with CME + CVL (n = 4), right colectomy (n = 6), and sigmoid colectomy (n = 1). Operative time significantly decreased after 25 cases (early phase vs. late phase; operative time 295.0 min vs. 250.0 min, p = 0.015; docking time 16.0 min vs. 12.0 min, p = 0.001; console time 212.0 min vs. 190.0 min, p = 0.019). Planned procedures were successfully completed in all patients. Postoperative outcomes were acceptable with only six cases of mild adverse events through a 3-month follow-up. No local recurrence and only one case of systemic recurrence occurred within 1 year postoperatively.

CONCLUSIONS

This study demonstrated the surgical and oncological safety and feasibility of dVSP, which may be a novel surgical platform for colorectal surgery.

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.

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.

SENP2 regulates mitochondrial function and insulin secretion in pancreatic β 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 β cells by generating a β cell-specific knockout (Senp2-βKO) mouse model. Glucose tolerance and insulin secretion were significantly impaired in the Senp2-βKO mice. In addition, glucose-stimulated insulin secretion (GSIS) was decreased in the islets of the Senp2-βKO mice without a significant change in insulin synthesis. Furthermore, islets of the Senp2-βKO 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 β 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 β 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 β cells.

An Essential Role of the N-Terminal Region of ACSL1 in Linking Free Fatty Acids to Mitochondrial β-Oxidation in C2C12 Myotubes

Free fatty acids are converted to acyl-CoA by long-chain acyl-CoA synthetases (ACSLs) before entering into metabolic pathways for lipid biosynthesis or degradation. ACSL family members have highly conserved amino acid sequences except for their N-terminal regions. Several reports have shown that ACSL1, among the ACSLs, is located in mitochondria and mainly leads fatty acids to the β-oxidation pathway in various cell types. In this study, we investigated how ACSL1 was localized in mitochondria and whether ACSL1 overexpression affected fatty acid oxidation (FAO) rates in C2C12 myotubes. We generated an ACSL1 mutant in which the N-terminal 100 amino acids were deleted and compared its localization and function with those of the ACSL1 wild type. We found that ACSL1 adjoined the outer membrane of mitochondria through interaction of its N-terminal region with carnitine palmitoyltransferase-1b (CPT1b) in C2C12 myotubes. In addition, overexpressed ACSL1, but not the ACSL1 mutant, increased FAO, and ameliorated palmitate-induced insulin resistance in C2C12 myotubes. These results suggested that targeting of ACSL1 to mitochondria is essential in increasing FAO in myotubes, which can reduce insulin resistance in obesity and related metabolic disorders.

Metformin Ameliorates Lipotoxic β-Cell Dysfunction through a Concentration-Dependent Dual Mechanism of Action

BACKGROUND

Chronic exposure to elevated levels of free fatty acids contributes to pancreatic β-cell dysfunction. Although it is well known that metformin induces cellular energy depletion and a concomitant activation of AMP-activated protein kinase (AMPK) through inhibition of the respiratory chain, previous studies have shown inconsistent results with regard to the action of metformin on pancreatic β-cells. We therefore examined the effects of metformin on pancreatic β-cells under lipotoxic stress.

METHODS

NIT-1 cells and mouse islets were exposed to palmitate and treated with 0.05 and 0.5 mM metformin. Cell viability, glucose-stimulated insulin secretion, cellular adenosine triphosphate, reactive oxygen species (ROS) levels and Rho kinase (ROCK) activities were measured. The phosphorylation of AMPK was evaluated by Western blot analysis and mRNA levels of endoplasmic reticulum (ER) stress markers and NADPH oxidase (NOX) were measured by real-time quantitative polymerase chain reaction analysis.

RESULTS

We found that metformin has protective effects on palmitate-induced β-cell dysfunction. Metformin at a concentration of 0.05 mM inhibits NOX and suppresses the palmitate-induced elevation of ER stress markers and ROS levels in a AMPK-independent manner, whereas 0.5 mM metformin inhibits ROCK activity and activates AMPK.

CONCLUSION

This study suggests that the action of metformin on β-cell lipotoxicity was implemented by different molecular pathways depending on its concentration. Metformin at a usual therapeutic dose is supposed to alleviate lipotoxic β-cell dysfunction through inhibition of oxidative stress and ER stress.

SUMO-specific protease 2 mediates leptin-induced fatty acid oxidation in skeletal muscle

BACKGROUND AND PURPOSE

In addition to the central nervous system-mediated action, leptin also directly induces fatty acid oxidation in skeletal muscle. Rapid induction of FAO by leptin is mediated by the AMP-activated protein kinase (AMPK) pathway, but the mechanism of prolonged FAO by leptin was previously unknown. In an earlier study, we showed that free fatty acids increase transcription of small ubiquitin-like modifier (SUMO) specific protease 2 (SENP2) in skeletal muscle, and that SENP2 stimulates expression of FAO-associated enzymes by deSUMOylating peroxisome proliferator-activated receptors, PPARδ and PPARγ. In this study, we examine whether SENP2 is involved in prolonged stimulation of FAO by leptin.

METHODS

The Effect of leptin on expression of SENP2 and on SENP2-mediated FAO was investigated by using western blotting and real time qPCR of C2C12 myotubes, and of C2C12 myotubes in which expression of specific genes was knocked down using siRNAs. Additionally, muscle-specific SENP2 knockout mice were generated to test the involvement of SENP2 in leptin-induced FAO in vivo.

RESULTS

We show that leptin treatment of C2C12 myotubes causes signal transducer and activator of transcription 3 (STAT3) to bind to the Senp2 promoter, inducing SENP2 expression. We also show that leptin increases the binding of PPARδ and PPARγ to PPRE sites in the promoters of two FAO-associated genes: long-chain acyl-CoA synthetase 1 (Acsl1) or carnitine palmitoyl transferase 1b (Cpt1b). When SENP2 is knocked down in myotubes, leptin-induced expression of FAO-associated enzymes and prolonged increase of FAO are suppressed, but rapid increase of FAO is unaffected. In addition, leptin-induced expression of FAO-associated enzymes was not observed in muscle tissue of SENP2 knockout mice.

CONCLUSIONS

We demonstrate that the peripheral actions of leptin on FAO are mediated by two different pathways: AMPK causes a rapid increase in FAO, and SENP2 of the STAT3 pathway causes a slow, prolonged increase in FAO.

Direct differentiation of bone marrow mononucleated cells into insulin producing cells using pancreatic β-cell-derived components

Transplantation of stem cell-derived insulin producing cells (IPCs) has been proposed as an alternative to islet transplantation for the treatment of diabetes mellitus. However, current IPC differentiation protocols are focused on generating functional cells from the pluripotent stem cells and tend to rely on multistep, long-term exposure to various exogenous factors. In this study, we addressed the observation that under stress, pancreatic β-cells release essential components that direct the differentiation of the bone marrow nucleated cells (BMNCs) into IPCs. Without any supplementation with known differentiation-inducing factors, IPCs can be generated from BMNCs by in vitro priming for 6 days with conditioned media (CM) from the β-cells. In vitro primed BMNCs expressed the β-cell-specific transcription factors, as well as insulin, and improved hyperglycemia and glucose intolerance after transplantation into the streptozotocin-induced diabetic mice. Furthermore, we have found that components of the CM which trigger the differentiation were enclosed by or integrated into micro particles (MPs), rather than being secreted as soluble factors. Identification of these differentiation-directing factors might enable us to develop novel technologies required for the production of clinically applicable IPCs.

Re-highlighting the action of PPARγ in treating metabolic diseases

Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor family and plays an important role in adipocyte differentiation, glucose homeostasis, and insulin sensitivity. Thiazolidinediones (TZDs), synthetic ligands of PPARγ, have been used for the treatment of diabetes mellitus for two decades. TZDs were expected to be amazing drugs not only for type 2 diabetes but also for metabolic syndrome and atherosclerotic vascular disease because they can reduce both insulin resistance and inflammation in experimental studies. However, serious unwanted effects pushed TZDs back to an optional second-tier drug for type 2 diabetes. Nevertheless, PPARγ is still one of the most important targets for the treatment of insulin resistance and diabetes mellitus, and novel strategies to modulate PPARγ activity to enhance its beneficial effects and reduce unwanted adverse effects are anticipated. Recent studies showed that post-translational modification (PTM) of PPARγ regulates PPARγ activity or stability and may be a novel way to optimize PPARγ activity with reduced adverse effects. In this review, we will focus on recent advances in PTM of PPARγ and the mechanisms regulating PPARγ function as well as in the development of PPARγ modulators or agonists.

Select antibiotics in leachate from closed and active landfills exceed thresholds for antibiotic resistance development

Though antibiotic resistance (ABR) represents a major global health threat, contributions of landfill leachate to the life cycle of antibiotics and ABR development are poorly understood in rapidly urbanizing regions of developing countries. We selected one of the largest active landfills in Asia and two landfills that have been closed for 20 years to examine antibiotic occurrences in leachates and associated hazards during wet and dry season sampling events. We focused on some of the most commonly used human antibiotics in Hong Kong, one of the most populous Asian cities and the fourth most densely populated cities in the world. Seven antibiotics (cephalexin [CLX], chloramphenicol [CAP], ciprofloxacin [CIP], erythromycin [ERY], roxithromycin [ROX], trimethoprim [TMP], sulfamethoxazole [SMX]) were quantitated using HPLC-MS/MS generally following previously reported methods. Whereas CLX, CAP, ROX and SMX in leachates did not exceed ABR predicted no effect concentrations (PNECs), exceedances were observed for CIP, ERY and TMP in some study locations and on some dates. In fact, an ABR PNEC for CIP was exceeded in leachates during both sampling periods from all study locations, including leachates that are directly discharged to coastal systems. These findings highlight the importance of developing an advanced understanding of pharmaceutical access, usage and disposal practices, effectiveness of intervention strategies (e.g., leachate treatment technologies, drug take-back schemes), and contributions of landfill leachates to the life cycle of antibiotics and ABR development, particularly in rapidly urbanizing coastal regions with less advanced waste management systems than Hong Kong.

Analgesic Efficacy and Safety of Prolonged-Release Oxycodone/Naloxone in Korean Patients with Chronic Pain from Spinal Disorders

Background

A prolonged-release formulation of oxycodone/naloxone has been shown to be effective in European populations for the management of chronic moderate to severe pain. However, no clinical data exist for its use in Korean patients. The objective of this study was to assess efficacy and safety of prolonged-release oxycodone/naloxone in Korean patients for management of chronic moderate-to-severe pain.

Methods

In this multicenter, single-arm, open-label, phase IV study, Korean adults with moderate-to-severe spinal disorder-related pain that was not satisfactorily controlled with weak opioids and nonsteroidal anti-inflammatory drugs received prolonged-release oral oxycodone/naloxone at a starting dose of 10/5 mg/day (maximum 80/40 mg/day) for 8 weeks. Changes in pain intensity and quality of life (QoL) were measured using a numeric rating scale (NRS, 0–10) and the Korean-language EuroQol-five dimensions questionnaire, respectively.

Results

Among 209 patients assessed for efficacy, the mean NRS pain score was reduced by 25.9% between baseline and week 8 of treatment (p < 0.0001). There was also a significant improvement in QoL from baseline to week 8 (p < 0.0001). The incidence of adverse drug reactions was 27.7%, the most common being nausea, constipation, and dizziness; 77.9% of these adverse drug reactions had resolved or were resolving at the end of the study.

Conclusions

Prolonged-release oxycodone/naloxone provided significant and clinically relevant reductions in pain intensity and improved QoL in Korean patients with chronic spinal disorders. (ClinicalTrials.gov identifier: NCT01811238)

Carnitine induces autophagy and restores high-fat diet-induced mitochondrial dysfunction

OBJECTIVE

Autophagy is suppressed in skeletal muscle and the liver with insulin resistance induced by a high-fat diet. Autophagy is essential for maintaining mitochondrial function, and dysfunctional mitochondria are associated with insulin resistance. As carnitine treatment is well known to improve insulin resistance by promoting mitochondrial function, we investigated if carnitine affects autophagy in the skeletal muscle of a high-fat diet-induced rodent model of obesity.

RESULTS

After 6weeks on a high-fat diet (48kcal% fat), mice developed glucose intolerance, and the gastrocnemius muscle showed a decrease in insulin signaling and mitochondrial function, which was reversed after carnitine (100mg/kg/day) treatment by oral gavage for 2weeks. Swollen mitochondria with destroyed cristae were observed in the skeletal muscle of high-fat diet-fed mice but were not there after carnitine treatment. High-fat diet decreased LC3B-II, a marker of autophagosome formation, and increased sequestosome 1 (SQSTM1), expression of which was reversed after carnitine treatment. In C2C12 myotubes, prolonged treatment with palmitate suppressed autophagy, which was relieved by carnitine treatment. However, the induction of autophagy by carnitine in C2C12 myotubes was not observed after knock-down of peroxisome proliferator-activated receptor γ (PPARγ), which is known to regulate autophagy.

CONCLUSION

We conclude that the removal of dysfunctional mitochondria by induction of autophagy through PPARγ may be a novel mechanism by which carnitine improves insulin resistance and mitochondrial dysfunction in obesity.

Autologous adipose tissue-derived stem cells for the treatment of complex perianal fistulas not associated with Crohn's disease: a phase II clinical trial for safety and efficacy

PURPOSE

Injection of adipose tissue-derived stem cells (ASCs) is a novel method for the treatment of complex perianal fistulas. We aimed to evaluate the safety and efficacy of ASCs in the treatment of complex anal fistulas not associated with Crohn's disease.

METHODS

A phase II clinical trial was performed comparing two different doses of ASCs (group 1: 1 × 10⁷ cells/mL and group 2: 2 × 10⁷ cells/mL). Eligible patients were administered an amount of ASCs proportional to the length of the fistula by injection into the submucosal layer surrounding the internal opening and inside of the fistula tract. ASCs at twice the initial concentration were administered if complete closure was not achieved within 8 weeks. The efficacy endpoint was the complete closure of fistulas 8 weeks after injection. Patients demonstrating complete closure at week 8 were subjected to follow-up for 6 months.

RESULTS

Fifteen patients were injected with ASCs; thirteen completed the study. Complete closure was observed in 69.2% (9/13) of patients at 8 weeks. Three of five patients in group 1, and six of eight in group 2 displayed complete closure; no significant differences were observed between the groups. Six of nine patients who showed complete closure participated in additional follow-up; five (83.3%) showed persistent response at 6 months. No grade 3 or 4 adverse events (AEs) were observed; observed AEs were not related to ASC treatment.

CONCLUSION

ASCs might be a good option for the treatment of complex perianal fistulas are not healed by conventional operative procedures.

Novel osmotin inhibits SREBP2 via the AdipoR1/AMPK/SIRT1 pathway to improve Alzheimer's disease neuropathological deficits

Extensive evidence has indicated that a high rate of cholesterol biogenesis and abnormal neuronal energy metabolism play key roles in Alzheimer's disease (AD) pathogenesis. Here, for we believe the first time, we used osmotin, a plant protein homolog of mammalian adiponectin, to determine its therapeutic efficacy in different AD models. Our results reveal that osmotin treatment modulated adiponectin receptor 1 (AdipoR1), significantly induced AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1) activation and reduced SREBP2 (sterol regulatory element-binding protein 2) expression in both in vitro and in vivo AD models and in Adipo^-/- mice. Via the AdipoR1/AMPK/SIRT1/SREBP2 signaling pathway, osmotin significantly diminished amyloidogenic Aβ production, abundance and aggregation, accompanied by improved pre- and post-synaptic dysfunction, cognitive impairment, memory deficits and, most importantly, reversed the suppression of long-term potentiation in AD mice. Interestingly, AdipoR1, AMPK and SIRT1 silencing not only abolished osmotin capability but also further enhanced AD pathology by increasing SREBP2, amyloid precursor protein (APP) and β-secretase (BACE1) expression and the levels of toxic Aβ production. However, the opposite was true for SREBP2 when silenced using small interfering RNA in APPswe/ind-transfected SH-SY5Y cells. Similarly, osmotin treatment also enhanced the non-amyloidogenic pathway by activating the α-secretase gene that is, ADAM10, in an AMPK/SIRT1-dependent manner. These results suggest that osmotin or osmotin-based therapeutic agents might be potential candidates for AD treatment.

Thyroid-stimulating hormone improves insulin sensitivity in skeletal muscle cells via cAMP/PKA/CREB pathway-dependent upregulation of insulin receptor substrate-1 expression

Thyroid-stimulating hormone (TSH) receptor is expressed in extrathyroidal tissues such as hepatocytes, adipocytes, and skeletal muscle, which suggests a possible novel role of TSH in various metabolic processes in extrathyroidal tissues independent of thyroid hormones. We investigated whether TSH has any effects on glucose tolerance and insulin sensitivity in the skeletal muscle using diet-induced obesity (DIO) mouse models and rodent skeletal muscle cells. TSH improved glucose tolerance in DIO mice and this was associated with an improvement of skeletal muscle insulin sensitivity resulting from the increased expression of insulin receptor substrate (IRS)-1 protein and mRNA therein. TSH significantly increased both basal and insulin-stimulated glucose transport in rat L6 myotubes and increased the expression of IRS-1 protein and mRNA in these cells as well. TSH also stimulated Irs1 promoter activation; this stimulation was abolished by protein kinase A (PKA) inhibition using H89 or by mutation of the cAMP-response element site located at -1155 to -875 bp of the Irs1 promoter region, supporting a novel role of TSH activated-cAMP/PKA/CREB signaling in the regulation of Irs1 expression. In conclusion, TSH improves insulin sensitivity in skeletal muscle by increasing Irs1 gene expression. This regulatory effect is mediated by a PKA-CREB-dependent pathway.

Rg3 Improves Mitochondrial Function and the Expression of Key Genes Involved in Mitochondrial Biogenesis in C2C12 Myotubes

BACKGROUND

Panax ginseng has glucose-lowering effects, some of which are associated with the improvement in insulin resistance in skeletal muscle. Because mitochondria play a pivotal role in the insulin resistance of skeletal muscle, we investigated the effects of the ginsenoside Rg3, one of the active components of P. ginseng, on mitochondrial function and biogenesis in C2C12 myotubes.

METHODS

C2C12 myotubes were treated with Rg3 for 24 hours. Insulin signaling pathway proteins were examined by Western blot. Cellular adenosine triphosphate (ATP) levels and the oxygen consumption rate were measured. The protein or mRNA levels of mitochondrial complexes were evaluated by Western blot and quantitative reverse transcription polymerase chain reaction analysis.

RESULTS

Rg3 treatment to C2C12 cells activated the insulin signaling pathway proteins, insulin receptor substrate-1 and Akt. Rg3 increased ATP production and the oxygen consumption rate, suggesting improved mitochondrial function. Rg3 increased the expression of peroxisome proliferator-activated receptor γ coactivator 1α, nuclear respiratory factor 1, and mitochondrial transcription factor, which are transcription factors related to mitochondrial biogenesis. Subsequent increased expression of mitochondrial complex IV and V was also observed.

CONCLUSION

Our results suggest that Rg3 improves mitochondrial function and the expression of key genes involved in mitochondrial biogenesis, leading to an improvement in insulin resistance in skeletal muscle. Rg3 may have the potential to be developed as an anti-hyperglycemic agent.

F-box only protein 9 is an E3 ubiquitin ligase of PPARγ

Peroxisome proliferator-activated receptor gamma (PPARγ) is a critical regulator of carbohydrate and lipid metabolism, adipocyte differentiation and inflammatory response. Post-translational modification of PPARγ and its degradation involve several pathways, including the ubiquitin–proteasome system. Here, we identified F-box only protein 9 (FBXO9) as an E3 ubiquitin ligase of PPARγ. We screened interacting partners of PPARγ using immunoprecipitation and mass spectrometric analysis and identified FBXO9 as an E3 ubiquitin ligase of PPARγ. FBXO9 directly interacted with PPARγ through the activation function-1 domain and ligand-binding domain. FBXO9 decreased the protein stability of PPARγ through induction of ubiquitination. We found that the F-box motif of FBXO9 was required for its ubiquitination function. The activity of PPARγ was significantly decreased by FBXO9 overexpression. Furthermore, FBXO9 overexpression in 3T3-L1 adipocytes resulted in decreased levels of endogenous PPARγ and suppression of adipogenesis. These results suggest that FBXO9 is an important enzyme that regulates the stability and activity of PPARγ through ubiquitination.

DMC (2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone) improves glucose tolerance as a potent AMPK activator

OBJECTIVE

We investigated the effect and regulatory mechanism of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) isolated from Cleistocalyx operculatus on metabolic parameters in myotubes, adipocytes and an obese mouse model.

MATERIALS AND METHODS

Myotubes and adipocytes were incubated with or without DMC. Glucose uptake, fatty acid oxidation, AMPK activation and adipocytes differentiation were investigated. To examine in vivo effect of DMC, 30mg/kg/day DMC was administered by oral gavage for 2weeks in high fat fed C57BL/6 male mice and intra-peritoneal glucose tolerance test was performed. In order to examine whether DMC directly activates AMPK, we performed cell free AMPK assay and surface plasmon resonance spectroscopy analysis.

RESULT

DMC increases glucose uptake and fatty acid oxidation (FAO) in myotubes. Also, DMC inhibits adipocyte differentiation in 3T3-L1 cells. Interestingly, DMC stimulates phosphorylation of AMP-dependent protein kinase (AMPK) alpha subunit (T172) by directly binding to AMPK, which results in the activation of AMPK. Furthermore, DMC binds AMPK with a higher affinity than AMP. When AMPK was knocked down, the stimulatory effect of DMC on FAO and its inhibitory effect on adipogenesis were abolished. These results suggest that the effects of DMC were primarily mediated by AMPK activation. In addition, treating mice fed a high fat diet with DMC improved glucose tolerance and significantly increased FAO of the muscles.

CONCLUSION

DMC, as a novel AMPK activator, shows anti-diabetic effects in cell culture systems, such as myotubes and adipocytes, and in a diet-induced obese mouse model.

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.

Thyroid Hormone Regulates the mRNA Expression of Small Heterodimer Partner through Liver Receptor Homolog-1

BACKGROUND

Expression of hepatic cholesterol 7α-hydroxylase (CYP7A1) is negatively regulated by orphan nuclear receptor small heterodimer partner (SHP). In this study, we aimed to find whether thyroid hormone regulates SHP expression by modulating the transcriptional activities of liver receptor homolog-1 (LRH-1).

METHODS

We injected thyroid hormone (triiodothyronine, T3) to C57BL/6J wild type. RNA was isolated from mouse liver and used for microarray analysis and quantitative real-time polymerase chain reaction (PCR). Human hepatoma cell and primary hepatocytes from mouse liver were used to confirm the effect of T3 in vitro. Promoter assay and electrophoretic mobility-shift assay (EMSA) were also performed using human hepatoma cell line.

RESULTS

Initial microarray results indicated that SHP expression is markedly decreased in livers of T3 treated mice. We confirmed that T3 repressed SHP expression in the liver of mice as well as in mouse primary hepatocytes and human hepatoma cells by real-time PCR analysis. LRH-1 increased the promoter activity of SHP; however, this increased activity was markedly decreased after thyroid hormone receptor β/retinoid X receptor α/T3 administration. EMSA revealed that T3 inhibits specific LRH-1 DNA binding.

CONCLUSION

We found that thyroid hormone regulates the expression of SHP mRNA through interference with the transcription factor, LRH-1.

SUMO-Specific Protease 2 (SENP2) Is an Important Regulator of Fatty Acid Metabolism in Skeletal Muscle

Small ubiquitin-like modifier (SUMO)-specific proteases (SENPs) that reverse protein modification by SUMO are involved in the control of numerous cellular processes, including transcription, cell division, and cancer development. However, the physiological function of SENPs in energy metabolism remains unclear. Here, we investigated the role of SENP2 in fatty acid metabolism in C2C12 myotubes and in vivo. In C2C12 myotubes, treatment with saturated fatty acids, like palmitate, led to nuclear factor-κB-mediated increase in the expression of SENP2. This increase promoted the recruitment of peroxisome proliferator-activated receptor (PPAR)δ and PPARγ, through desumoylation of PPARs, to the promoters of the genes involved in fatty acid oxidation (FAO), such as carnitine-palmitoyl transferase-1 (CPT1b) and long-chain acyl-CoA synthetase 1 (ACSL1). In addition, SENP2 overexpression substantially increased FAO in C2C12 myotubes. Consistent with the cell culture system, muscle-specific SENP2 overexpression led to a marked increase in the mRNA levels of CPT1b and ACSL1 and thereby in FAO in the skeletal muscle, which ultimately alleviated high-fat diet-induced obesity and insulin resistance. Collectively, these data identify SENP2 as an important regulator of fatty acid metabolism in skeletal muscle and further implicate that muscle SENP2 could be a novel therapeutic target for the treatment of obesity-linked metabolic disorders.

Retinoid X receptor α overexpression alleviates mitochondrial dysfunction-induced insulin resistance through transcriptional regulation of insulin receptor substrate 1

Mitochondrial dysfunction is associated with insulin resistance and diabetes. We previously showed that retinoid X receptor α (RXRα) played an important role in transcriptional regulation of oxidative phosphorylation (OXPHOS) genes in cells with mitochondrial dysfunction caused by mitochondrial DNA mutation. In this study, we investigated whether mitochondrial dysfunction induced by incubation with OXPHOS inhibitors affects insulin receptor substrate 1 (IRS1) mRNA and protein levels and whether RXRα activation or overexpression can restore IRS1 expression. Both IRS1 and RXRα protein levels were significantly reduced when C2C12 myotubes were treated with the OXPHOS complex inhibitors, rotenone and antimycin A. The addition of RXRα agonists, 9-cis retinoic acid (9cRA) and LG1506, increased IRS1 transcription and protein levels and restored mitochondrial function, which ultimately improved insulin signaling. RXRα overexpression also increased IRS1 transcription and mitochondrial function. Because RXRα overexpression, knock-down, or activation by LG1506 regulated IRS1 transcription mostly independently of mitochondrial function, it is likely that RXRα directly regulates IRS1 transcription. Consistent with the hypothesis, we showed that RXRα bound to the IRS1 promoter as a heterodimer with peroxisome proliferator-activated receptor δ (PPARδ). These results suggest that RXRα overexpression or activation alleviates insulin resistance by increasing IRS1 expression.

Mitochondrial Complexes I and II Are More Susceptible to Autophagy Deficiency in Mouse β-Cells

BACKGROUND

Damaged mitochondria are removed by autophagy. Therefore, impairment of autophagy induces the accumulation of damaged mitochondria and mitochondrial dysfunction in most mammalian cells. Here, we investigated mitochondrial function and the expression of mitochondrial complexes in autophagy-related 7 (Atg7)-deficient β-cells.

METHODS

To evaluate the effect of autophagy deficiency on mitochondrial function in pancreatic β-cells, we isolated islets from Atg7(F/F):RIP-Cre+ mice and wild-type littermates. Oxygen consumption rate and intracellular adenosine 5'-triphosphate (ATP) content were measured. The expression of mitochondrial complex genes in Atg7-deficient islets and in β-TC6 cells transfected with siAtg7 was measured by quantitative real-time polymerase chain reaction.

RESULTS

Baseline oxygen consumption rate of Atg7-deficient islets was significantly lower than that of control islets (P<0.05). Intracellular ATP content of Atg7-deficient islets during glucose stimulation was also significantly lower than that of control islets (P<0.05). By Oxygraph-2k analysis, mitochondrial respiration in Atg7-deficient islets was significantly decreased overall, although state 3 respiration and responses to antimycin A were unaffected. The mRNA levels of mitochondrial complexes I, II, III, and V in Atg7-deficient islets were significantly lower than in control islets (P<0.05). Down-regulation of Atg7 in β-TC6 cells also reduced the expression of complexes I and II, with marginal significance (P<0.1).

CONCLUSION

Impairment of autophagy in pancreatic β-cells suppressed the expression of some mitochondrial respiratory complexes, and may contribute to mitochondrial dysfunction. Among the complexes, I and II seem to be most vulnerable to autophagy deficiency.

Autophagy deficiency in β cells blunts incretin-induced suppression of glucagon release from α cells

Incretin-based therapy such as GLP-1 receptor agonists and DPP-4 inhibitors for type 2 diabetes mellitus is characterized by glucose-dependent insulin secretion and glucose-inhibited glucagon secretion. Recently, autophagy deficiency in islet β cells has been shown to contribute to the pathogenesis of type 2 diabetes mellitus however, with the role of incretin has not been established. To evaluate the role of autophagy in incretin effects, 8-week-old male β cell-specific Atg7 knockout (Atg7(Δβ cell)) mice and wild-type mice were administered vildagliptin for 12 weeks. Vildagliptin treatment improved glucose intolerance and hypoinsulinemia; however, it failed to suppress serum glucagon levels after glucose loading in the Atg7(Δβ cell) mice. Ex vivo glucose-induced glucagon suppression was also blunted in the islets from vildagliptin-treated Atg7(Δβ cell) mice. The α cell mass was not affected by β cell autophagy deficiency or vildagliptin. However, glucagon mRNA expression was significantly increased by vildagliptin in the autophagy-deficient islets, and was significantly reduced by vildagliptin in wild-type islets. Pancreatic glucagon contents were not in agreement with the changes in mRNA expression, suggesting a dysregulation in glucagon translation and secretion. In vitro studies revealed that glucose-stimulated cAMP production was impaired in the autophagy-deficient islets exposed to exendin-4. Taken together, the results suggest that the constitutive autophagy in β cells could regulate incretin-induced glucagon expression and release in α cells, and that cAMP may play a role in this process.

Identification and Functional Characterization of P159L Mutation in HNF1B in a Family with Maturity-Onset Diabetes of the Young 5 (MODY5)

Mutation in HNF1B, the hepatocyte nuclear factor-1β (HNF-1β) gene, results in maturity-onset diabetes of the young (MODY) 5, which is characterized by gradual impairment of insulin secretion. However, the functional role of HNF-1β in insulin secretion and glucose metabolism is not fully understood. We identified a family with early-onset diabetes that fulfilled the criteria of MODY. Sanger sequencing revealed that a heterozygous P159L (CCT to CTT in codon 159 in the DNA-binding domain) mutation in HNF1B was segregated according to the affected status. To investigate the functional consequences of this HNF1B mutation, we generated a P159L HNF1B construct. The wild-type and mutant HNF1B constructs were transfected into COS-7 cells in the presence of the promoter sequence of human glucose transporter type 2 (GLUT2). The luciferase reporter assay revealed that P159L HNF1B had decreased transcriptional activity compared to wild-type (p < 0.05). Electrophoretic mobility shift assay showed reduced DNA binding activity of P159L HNF1B. In the MIN6 pancreatic β-cell line, overexpression of the P159L mutant was significantly associated with decreased mRNA levels of GLUT2 compared to wild-type (p < 0.05). However, INS expression was not different between the wild-type and mutant HNF1B constructs. These findings suggests that the impaired insulin secretion in this family with the P159L HNF1B mutation may be related to altered GLUT2 expression in β-cells rather than decreased insulin gene expression. In conclusion, we have identified a Korean family with an HNF1B mutation and characterized its effect on the pathogenesis of diabetes.

Ex vivo pre-conditioning of hematopoietic stem/progenitor cells impairs long-term hematopoietic repopulation after transplantation (TRAN3P.881)

A number of investigators have tried to facilitate engraftment with limited numbers of available HSPCs by enhancing responsiveness of HSPCs to CXCL12. Recently, granulocyte derived cationic peptide, LL-37, has been suggested as a useful pre-conditioning component to overcome the shortage of available HSPCs. In this study, we first evaluated the character of LL-37 pre-conditioned HSPCs and found that LL-37 pre-conditioning effects are specific only to the clonogenic stem cells which are considered relatively dormant. This raised our concern regarding the fate of LL-37 pre-conditioned cells after transplantation and led us to evaluate their repopulation capacity as HSPCs. Not betraying our expectations, hematopoietic recovery of LL-37 pre-conditioned cells gradually decreased from 4 weeks after transplantation in competitive repopulation experiments. Further, in vitro studies revealed that LL-37 lead HSPCs to be more vulnerable to extracellular stimuli such as extracellular glucose followed by increased calcium influx from extracellular sources, which dampen self-renewal capacity by activating mammalian target of rapamycin and its downstream signaling. These results suggest that a future strategy must focus on maintaining HSPCs in dormant and protecting them from various stimuli during their long journey to the bone marrow niches rather than activating them before transplantation for successful transplantation outcome.

Risk factors of heavy episodic drinking among Korean adolescents

The main objective of this study was to identify the risk factors and develop a decision tree model of heavy episodic drinking (HED) among adolescents. Data were obtained from a representative nationwide Korean population. Nine variables (such as last 30 days smoking, school grade, sex, depression, school achievement, level of stress, region, and economic status) were found as risk factors of HED. On the highest level of the tree root, major classification rule was played by dividing based on the last 30 days smoking and school grades. These findings should be helpful for school and mental healthcare providers to detect Korean adolescents with high possibility of HED, which will aid in planning of healthcare interventions for at-risk adolescents.

Characteristics of falls in the epilepsy monitoring unit: a retrospective study

Falls are an important adverse event in an epilepsy monitoring unit (EMU). We identified patterns of falls in an EMU and compared them with risk factors for inpatient falls. Twenty-six patients with 26 falls (2.3% of admissions) in the EMU were compared with 50 general neurology inpatients with 56 falls over a 4-year period. In the EMU, the majority (62%) of falls happened during the first 3 days of admission, mostly in the bathroom (74%), in patients with a normal mental status (77%). Most general inpatients fell after the third day (64%), inside their rooms (68%), and had an altered mental status before the fall (68%). All 26 EMU patients were identified as high risk at admission, in spite of which falls were not prevented. We outline these differences between EMU patients and general inpatients and highlight the practice gap in preventing falls in an EMU.

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.

4-Deoxypyridoxine improves the viability of isolated pancreatic islets ex vivo

The successful islet transplantation, for the treatment of type 1 diabetes, depends on the quantity and the quality of transplanted islets. Previously, it has reported that the significant loss of isolated islet mass could be prevented by sphingolipid metabolite, sphinogosine 1-phophate (S1P). This study was performed to elucidate whether the beneficial effects of S1P maintaining isolated pancreatic islets ex vivo are mimicked by modulation of intracellular S1P. We tested the in vitro effect of various agents that modulate intracellular S1P levels in insulinoma cell lines and isolated islets to compare their anti-apoptotic effects with that of S1P. As results, we discovered that 4-deoxypyridoxine (DOP), which inhibits the degradation of intracellular S1P by inhibiting S1P lyase (SPL) activity, minimized the chemically induced apoptosis of insulinoma cell lines as S1P did. Also, supplementation of DOP in the culture media protected the regression of isolated islets that have been maintained ex vivo at least for 18 h providing the evidence of increasing viability of isolated islets with DOP, which impaired SPL activity. In conclusion, these results suggest that the application of SPL inhibitors could be considered as a supplement for the maintenance of viable islets isolated from donor sources in the process of islet transplantation.

Granulocyte derived cationic peptide LL-37 prime hematopoietic progenitor cells through up-regulating glucose uptake and AMPK signaling (P2202)

It has been reported that activated granulocytes derived cationic peptide LL-37 positively prime responsiveness of hematopoietic progenitor cells (HPCs) to CXCL12 gradient through an ambiguous pathway. The goal of this study was to elucidate the mechanism of enhanced migration of LL-37 primed HPCs to CXCL12 gradient. We performed in vitro migration assay and found out that LL-37 pretreatment enhanced migration of HPCs to CXCL12 only in the presence of D-glucose, but not in the absence of glucose or in the presence of glucose uptake inhibitor, 2-deoxy-D-glucose (2-DG). This signifies that LL-37 may affect intracellular energy production machinery. So we tested if the priming effect of LL-37 is related to mTOR signaling since mTOR is a central regulator of nutrient sensing and glycolysis promoting glucose uptake and ATP production to match energy demands for cell migration. As we expected, LL-37 induced glucose uptake in mTOR signaling dependent manner. Also, LL-37 induced the activation of nutrient sensing AMPK and its downstream substrates. In line with this, pretreatment of AMPK activator AICAR promoted migration of HSPCs as well. These findings demonstrate that the priming mechanism of LL-37 is closely associated with increasing ATP production and the optimization of glucose uptake and ATP production for HPCs prior to transplantation would be particularly important in HPCs transplantation where the number of cells available for transplantation is usually limited.

The potential of endothelial colony-forming cells to improve early graft loss after intraportal islet transplantation

Early graft loss in islet transplantation means that a large amount of donor islets is required. Endothelial cells and endothelial colony-forming cells (ECFCs) have been reported to improve instant blood-mediated inflammatory reaction (IBMIR) in vitro. In this study, we examined if ECFC-coated porcine islets would prevent early graft loss in vivo. Human ECFCs were prepared from cord blood and cocultured with islets to make composite grafts. Diabetic nude mice underwent intraportal transplantation. Blood glucose levels were monitored, and morphological examination of the grafts along with analysis of the components of IBMIR and inflammatory reaction were performed with the liver tissues. The ECFC-coated islets significantly decreased blood glucose levels immediately after transplantation compared to the uncoated islets. Composite ECFC islet grafts were observed in the liver sections, associated with a more insulin(+) area compared to that of the uncoated group within 48 h after transplantation. Deposition of CD41a, C5b-9, and CD11b(+) cells was also decreased in the ECFC-coated group. Expression of porcine HMGB1 and mouse TNF-α was increased in the transplantated groups compared to the sham operation group, with a trend of a decreasing trend across the uncoated group, the ECFC-coated group, and the sham group. We demonstrated that the composite ECFC porcine islets transplanted into the portal vein of nude mice improved early graft loss and IBMIR in vivo.

Postoperative changes in pelvic parameters and sagittal balance in adult isthmic spondylolisthesis

BACKGROUND

Correction of deformity in adult isthmic spondylolisthesis can affect the pelvic parameters and sagittal balance.

OBJECTIVE

To evaluate the correlation with the amount of deformity correction and the subsequent change in pelvic parameters after surgical correction of adult isthmic spondylolisthesis and to determine which deformity parameter most affects the postoperative restoration of spinopelvic sagittal alignment.

METHODS

Fifty-eight patients with 1-level isthmic spondylolisthesis were included. Their average age was 55 years (range, 24-76 years). All patients underwent operation by posterior lumbar interbody fusion and posterior instrumentation. The pre- and postoperative sacral slope, pelvic tilt, lumbar lordosis (LL), and sagittal balance were measured, and then the correlation between these parameters and deformity parameters such as slip degree, slip angle, and height of the intervertebral disc (HOD) was evaluated.

RESULTS

The slip degree, slip angle, and HOD were significantly recovered after surgery. Pelvic parameters and sagittal balance changed subsequently. Sacral slope was increased by 4.4 degrees, and pelvic tilt was decreased by 4.4 degrees. LL was increased by 5.2 degrees and sagittal balance was displaced 5.6 mm posteriorly. Only the restoration of the HOD showed a significant correlation with the change in LL (r = 0.305, P = .02) and sagittal balance (r = 0.377, P = .004).

CONCLUSION

Surgical correction of adult isthmic spondylolisthesis with posterior lumbar interbody fusion and posterior instrumentation resulted in improvement of sacral slope, pelvic tilt, LL, and sagittal balance. Only restoration of the HOD was significantly correlated with improvement of LL and sagittal balance. Therefore we presume it is important to restore the HOD in surgical correction of adult isthmic spondylolisthesis.

Endothelial progenitor cell cotransplantation enhances islet engraftment by rapid revascularization

Impaired revascularization of transplanted islets is a critical problem that leads to progressive islet loss. Since endothelial progenitor cells (EPCs) are known to aid neovascularization, we aimed to enhance islet engraftment by cotransplanting EPCs with islets. Porcine islets, with (islet-EPC group) or without (islet-only group) human cord blood-derived EPCs, were transplanted into diabetic nude mice. The islet-EPC group reached euglycemia by ∼11 days posttransplantation, whereas the islet-only group did not. Also, the islet-EPC group had a higher serum porcine insulin level than the islet-only group. Islets from the islet-EPC group were more rapidly revascularized at the early period of transplantation without increment of final capillary density at the fully revascularized graft. Enhanced revascularization rate in the islet-EPC group was mainly attributed to stimulating vascular endothelial growth factor-A production from the graft. The rapid revascularization by EPC cotransplantation led to better graft perfusion and recovery from hypoxia. EPC cotransplantation was also associated with greater β-cell proliferation, probably by more basement membrane production and hepatocyte growth factor secretion. In conclusion, cotransplantation of EPCs and islets induces better islet engraftment by enhancing the rate of graft revascularization. These findings might provide a directly applicable tool to enhance the efficacy of islet transplantation in clinical practice.

Regulation of Wnt/β-catenin signaling by CCAAT/enhancer binding protein β during adipogenesis

Activation of the Wnt/β-catenin signaling pathway inhibits adipogenesis, while disruption of Wnt signaling leads to spontaneous adipogenesis. CCAAT/enhancer binding protein β (C/EBPβ) is rapidly induced in early stages of adipogenesis and is responsible for transcriptional induction of two major adipogenic transcription factors, peroxisome proliferator-activated receptor γ (PPARγ) and C/EBPα. In this study, we examined whether C/EBPβ is involved in the suppression of Wnt/β-catenin signaling during adipogenesis. Knockdown of C/EBPβ expression not only inhibited adipogenesis but also maintained active Wnt/β-catenin signaling, after addition of adipogenic inducers. In contrast, overexpression of C/EBPβ substantially inhibited Wnt signaling. Interestingly, our data showed that C/EBPβ is involved in the expression of Wnt10b, a major Wnt ligand in preadipocytes, even though C/EBPβ is not an essential factor to regulate Wnt10b expression during adipogenesis, and that C/EBPβ inhibits Wnt10b promoter activity by directly binding to specific regions of the promoter. These results suggest a dual function of C/EBPβ: stimulating expression of adipogenic genes and inhibiting Wnt signaling.

Mechanism for antioxidative effects of thiazolidinediones in pancreatic β-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 β-cells from oxidative stress, and we investigated the mechanism involved in this process. To generate oxidative stress in pancreatic β-cells (INS-1 and βTC3) 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 β-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 β-cells, and the knockdown of catalase significantly inhibited the antioxidant effect of TZDs. These results suggest that TZDs effectively protect pancreatic β-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 β-cells.

Effects of Sulfonylureas on Peroxisome Proliferator-Activated Receptor γ Activity and on Glucose Uptake by Thiazolidinediones

BACKGROUND

Sulfonylurea primarily stimulates insulin secretion by binding to its receptor on the pancreatic β-cells. Recent studies have suggested that sulfonylureas induce insulin sensitivity through peroxisome proliferator-activated receptor γ (PPARγ), one of the nuclear receptors. In this study, we investigated the effects of sulfonylurea on PPARγ transcriptional activity and on the glucose uptake via PPARγ.

METHODS

Transcription reporter assays using Cos7 cells were performed to determine if specific sulfonylureas stimulate PPARγ transactivation. Glimepiride, gliquidone, and glipizide (1 to 500 µM) were used as treatment, and rosiglitazone at 1 and 10 µM was used as a control. The effects of sulfonylurea and rosiglitazone treatments on the transcriptional activity of endogenous PPARγ were observed. In addition, 3T3-L1 adipocytes were treated with rosiglitazone (10 µM), glimepiride (100 µM) or both to verify the effect of glimepiride on rosiglitazone-induced glucose uptake.

RESULTS

Sulfonylureas, including glimepiride, gliquidone and glipizide, increased PPARγ transcriptional activity, gliquidone being the most potent PPARγ agonist. However, no additive effects were observed in the presence of rosiglitazone. When rosiglitazone was co-treated with glimepiride, PPARγ transcriptional activity and glucose uptake were reduced compared to those after treatment with rosiglitazone alone. This competitive effect of glimepiride was observed only at high concentrations that are not achieved with clinical doses.

CONCLUSION

Sulfonylureas like glimepiride, gliquidone and glipizide increased the transcriptional activity of PPARγ. Also, glimepiride was able to reduce the effect of rosiglitazone on PPARγ agonistic activity and glucose uptake. However, the competitive effect does not seem to occur at clinically feasible concentrations.

S-Adenosyl-L-methionine ameliorates TNFalpha-induced insulin resistance in 3T3-L1 adipocytes

An association between inflammatory processes and the pathogenesis of insulin resistance has been increasingly suggested. The IkappaB kinase-beta (IKK-beta)/ nuclear factor-kappaB (NF-kappaB) pathway is a molecular mediator of insulin resistance. S-Adenosyl-L-methionine (SAM) has both antioxidative and anti-inflammatory properties. We investigated the effects of SAM on the glucose transport and insulin signaling impaired by the tumor necrosis factor alpha (TNFalpha) in 3T3-L1 adipocytes. SAM partially reversed the basal and insulin stimulated glucose transport, which was impaired by TNFalpha. The TNFalpha-induced suppression of the tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1) and Akt in 3T3-L1 adipocytes was also reversed by SAM. In addition, SAM significantly attenuated the TNFalpha-induced degradation of IkappaB-alpha and NF-kappaB activation. Interestingly, SAM directly inhibited the kinase activity of IKK-beta in vitro. These results suggest that SAM can alleviate TNFalpha mediated-insulin resistance by inhibiting the IKK-beta/NF-kappaB pathway and thus can have a beneficial role in the treatment of type 2 diabetes mellitus.

Factitious stroke presenting for acute treatment

Four patients who were ultimately determined to have factitious neurological deficits were initially assessed as meeting eligibility criteria for treatment with intravenous recombinant tissue plasminogen activator (IV rt-PA), or enrollment in an acute stroke study. Two patients presented within the 3-hour IV rt-PA window; two presented between 4 and 6 hours after symptom onset. Evaluation by the Stroke Team responsible for IV rt-PA treatment or clinical study enrollment determined that three patients met all eligibility criteria, except for a fluctuating or rapidly improving deficit; these patients did not receive rt-PA or study enrollment. One patient whose deficit did not fluctuate or improve on Stroke Team evaluation was enrolled in an acute stroke study. Compared with 36 nonfactitious patients who received IV rt-PA or study enrollment, factitious patients were less likely to have facial weakness, aphasia, neglect, or visual field deficit. Because criteria for IV rt-PA and many stroke studies do not currently require imaging of a vascular occlusion or ischemic brain tissue, patients with factitious stroke may appear to meet these eligibility criteria. Physicians experienced in acute stroke evaluation and management are most likely to identify patients with factitious stroke and exclude them from consideration for thrombolysis or stroke study enrollment.

The ginsenoside Rg3 has a stimulatory effect on insulin signaling in L6 myotubes

The ginsenoside Rg3 is known to have a protective effect against hyperglycemia, obesity and diabetes in vivo. In this study, we examined the effect of Rg3 on insulin signaling and glucose uptake in cultured L6 myotubes. Rg3 increased glucose uptake both in the basal and insulin-induced states of L6 myotubes. Consistent with the increase in glucose uptake, Rg3 stimulated the phosphorylation of IRS-1 and Akt. Interestingly, Rg3 dramatically increased IRS-1 protein levels, while the protein level of Akt was not affected. Rg3 regulated IRS-1 expression at the transcriptional level and also increased the level of GLUT4 mRNA. Treatment of ginsam, in which Rg3 is the major compound of ginsenosides, increased the IRS-1 protein levels in OLEFT rats. In addition, we found that this effect of Rg3 on insulin signaling was not mediated by the AMPK pathway. In conclusion, these results suggest that Rg3 improves insulin signaling and glucose uptake primarily by stimulating the expression of IRS-1 and GLUT4.

Effect of a peroxisome proliferator-activated receptor gamma sumoylation mutant on neointimal formation after balloon injury in rats

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor regulating inflammation, atherosclerosis, insulin sensitivity and adipogenesis. Recently, it has been discovered that modification by the small ubiquitin-like modifier (SUMO) plays an important role in PPARgamma activity. In the present study, we investigated the effect of sumoylation on the antiatherogenic property of PPARgamma. PPARgamma-K107R sumoylation mutant, PPARgamma-wild type (WT) and control genes were transfected on vascular smooth muscle cells (VSMCs) to compare their effect on the proliferation and migration. Adenoviral vectors expressing the PPARgamma-K107R, PPARgamma-WT or control gene were delivered into the carotid arteries of rats after balloon injury. The PPARgamma-K107R increased the transcriptional activity of peroxisome proliferator response element (PPRE) and had a more potent transcriptional repression activity on the inducible nitric oxide synthase (iNOS) promoter as compared to the other sumoylation mutants or WT. PPARgamma-K107R or WT gene transfer inhibited VSMCs proliferation and migration to a greater extent than the control. The PPARgamma-K107R had more potent activity than PPARgamma-WT in this regard. PPARgamma-K107R or WT transfer showed a significantly lower intima-media ratio (IMR) than the control after balloon injury in rats. Again, the delivery of the PPARgamma-K107R decreased IMR further compared to PPARgamma-WT. In addition, the PPARgamma-K107R transfer showed a lower proliferation index and a higher apoptotic index than PPARgamma-WT. In conclusion, the PPARgamma sumoylation mutant K107R strongly inhibited VSMCs proliferation and migration, sustained apoptosis, and reduced neointimal formation after balloon injury. These results indicate that desumoylation at K107 in PPARgamma might play an important role against atherosclerosis.

Gamma knife radiosurgery for medically refractory idiopathic trigeminal neuralgia

Gamma knife radiosurgery (GKS) has been generally considered as a viable therapeutic option for the management of medically refractory idiopathic trigeminal neuralgia (TN). We reviewed our experience with GKS in patients with TN. Between Feb 1996 and May 2006, 77 patients with medical refractory idiopathic TN were treated using GKS. Thirty-six patients who had undergone other previous procedures, previous GKS, or had brain stem lesion, atypical symptoms, were excluded from this study. Pain improvement was achieved in 38 of the patients with TN (pain response rate 92.7%). Twenty-three patients were pain free and 15 had reduced pain. There were no serious complications. We think that GKS is an effective treatment option for patients with medical refractory idiopathic TN.

A mitochondrial DNA variant at position 16189 is associated with type 2 diabetes mellitus in Asians

AIMS/HYPOTHESIS

This multinational study was conducted to investigate the association between a mitochondrial DNA (mtDNA) T16189C polymorphism and type 2 diabetes in Asians. The mtDNA 16189C variant has been reported to be associated with insulin resistance and type 2 diabetes. However, a recent meta-analysis concluded that it is negatively associated with type 2 diabetes in Europids. Since the phenotype of an mtDNA mutant may be influenced by environmental factors and ethnic differences in the nuclear and mitochondrial genomes, we investigated the association between the 16189C variant and type 2 diabetes in Asians.

METHODS

The presence of the mtDNA 16189C variant was determined in 2,469 patients with type 2 diabetes and 1,205 non-diabetic individuals from Korea, Japan, Taiwan, Hong Kong and China. An additional meta-analysis including previously published Asian studies was performed. Since mtDNA nucleotide position 16189 is very close to the mtDNA origin of replication, we performed DNA-linked affinity chromatography and reverse-phase liquid chromatography/tandem mass spectrometry and chromatin immunoprecipitation to identify protein bound to the 16189 region.

RESULTS

Analysis of participants from five Asian countries confirmed the association between the 16189C variant and type 2 diabetes [odds ratio (OR) 1.256, 95% CI 1.08-1.46, p=0.003]. Inclusion of data from three previously published Asian studies (type 2 diabetes n=3,283, controls n=2,176) in a meta-analysis showed similar results (OR 1.335, 95% CI 1.18-1.51, p=0.000003). Mitochondrial single-stranded DNA-binding protein (mtSSB) was identified as a candidate protein bound to the 16189 region. Chromatin immunoprecipitation in cybrid cells showed that mtSSB has a lower binding affinity for the 16189C variant than the wild-type sequence.

CONCLUSIONS/INTERPRETATION

The mtDNA 16189C variant is associated with an increased risk of type 2 diabetes in Asians.

Faecal incontinence in male patients

OBJECTIVE

Data concerning faecal incontinence (FI) in men are lacking. The aim of this study was to evaluate the historical aetiology and contrast aetiologies in younger and older men suffering from FI.

METHOD

After institutional review board approval, a retrospective chart review was undertaken of all patients with FI seen between 1999 and 2005. The data of male patients was further analysed to assess the impact of age and historical aetiology on FI.

RESULTS

A total of 404 males were included, 203 patients were <70 years of age (group A) and 201 patients were >or=70 years of age (group B). The most common prior diagnosis in group A was perianal sepsis in 23 (11.3%) patients and symptomatic haemorrhoids in 20 (9.9%) patients; in group B it was prostate cancer in 57 (28.4%) patients, symptomatic haemorrhoids in 31 (15.4%) patients and neurological diseases in 18 (9%) patients. The most common prior procedure in group A was restorative proctectomy/proctocolectomy in 32 (15.8%) patients, fistulotomy or haemorrhoidectomy in 21 (10.3%) and 19 (9.4%) patients respectively. In group B, radiation therapy for prostate cancer was utilized in 48 (23.9%) patients and haemorrhoidectomy in 29 (14.4%) patients. Comparing group A and group B relative to diagnosis - perianal sepsis, perineal trauma, congenital disorders, HIV infection and anal cancer were more common in group A, whereas prostate cancer, neurological diseases and colon cancer were significantly more common in group B.

CONCLUSION

Prostate cancer, symptomatic haemorrhoids, perianal sepsis, rectal cancer and a history of restorative rectal resection were common associations with FI in men. The aetiologies for FI in men vary with age.

A new stapler-based full-thickness transgastric access closure: results from an animal pilot trial

BACKGROUND AND STUDY AIMS

Reliable closure of the transluminal incision is the crucial step for natural orifice transluminal endoscopic surgery (NOTES) procedures. The aim of this study was to evaluate the feasibility and effectiveness of transgastric access closure with a flexible stapling device in a porcine survival model.

PATIENTS AND METHODS

We carried out four experiments (two sterile and two nonsterile) on 50 kg pigs. The endoscope was passed through a gastrotomy made with a needle knife and an 18-mm controlled radial expansion dilating balloon. After peritoneoscopy, a flexible linear stapling device (NOLC60, Power Medical Interventions, Langhorne, Pennsylvania, USA) was perorally advanced over a guide wire into the stomach, positioned under endoscopic guidance, and opened to include the site of gastrotomy between its two arms; four rows of staples were fired. One animal was sacrificed 24 hours after the procedure (progression of pre-existing pneumonia). The remaining animals were survived for 1 week and then underwent repeat endoscopy and postmortem examination.

RESULTS

Peroral delivery and positioning of the stapling device involved some technical difficulties, mostly due to the short length (60 cm) of the stapling device. The stapler provided complete leak-resistant gastric closure in all pigs. None of the surviving animals had any clinical signs of infection. Necropsy demonstrated an intact staple line with full-thickness healing of the gastrotomy in all animals. Histologic examination confirmed healing, but also revealed intramural micro-abscesses within the gastric wall after nonsterile procedure.

CONCLUSIONS

Gastrotomy closure with a perorally delivered flexible stapling device created a leak-resistant transmural line of staples followed by full-thickness healing of the gastric wall incision. Increasing the length of the instrument and adding device articulation will further facilitate its use for NOTES procedures.