Non-fasting triglyceride levels in the Korean population with and without ischemic heart disease and cerebrovascular disease

BACKGROUND/AIMS

Associations between non-fasting triglyceride (TG) levels and a risk of ischemic heart disease (IHD) and cerebrovascular accident (CVA) have been suggested in Caucasians. We aimed to investigate whether non-fasting TG levels reflect the risk of IHD/CVA in Koreans.

METHODS

We conducted an analysis of patients aged ≥ 30 years from the nationwide survey database. Fasting TG was defined as a measurement taken ≥ 12 hours since the last meal. Non-fasting TG was categorized by fasting duration of 0 to 3, 4 to 7, and 8 to 11 hours.

RESULTS

In subjects without history of IHD/CVA, diabetes, or lipid-lowering medication, the TG level was significantly elevated for 7 hours in men compared to fasting TG levels (p = 0.011); the mean TG levels were 154.9 mg/dL (standard error [SE], 13.0), 177.0 mg/dL (SE, 12.1), 148.8 mg/dL (SE, 2.8), and 141.5 mg/dL (SE, 1.4) for 0 to 3, 4 to 7, 8 to 11, and ≥12 hours' fasting, respectively. In women, there was no difference in TG level according to fasting duration after adjustment for confounders. In men without diabetes, the TG level from 4 to 7 hours' fasting showed a significant difference between subjects with or without IHD/CVA even after adjustments for age, body mass index, lipid medication, exercise, and dietary factors (215.1 mg/dL vs. 177.3 mg/dL, p < 0.001).

CONCLUSION

In men, non-fasting TG levels from 4 to 7 hours' fasting were significantly associated with IHD/CVA, and were superior to fasting TG levels level in the significant association with the history of IHD or CVA.

The Effect of a Smartphone-Based, Patient-Centered Diabetes Care System in Patients With Type 2 Diabetes: A Randomized, Controlled Trial for 24 Weeks

OBJECTIVE

This study evaluated the efficacy of a smartphone-based, patient-centered diabetes care system (mDiabetes) for type 2 diabetes that contains comprehensive modules for glucose monitoring, diet, physical activity, and a clinical decision support system.

RESEARCH DESIGN AND METHODS

We conducted a 24-week, multicenter, randomized controlled trial with adult patients with inadequately controlled type 2 diabetes. The patients were randomly assigned to the mDiabetes group or the paper logbook (pLogbook) group. The primary end point was the difference of the change in HbA_1c from baseline between the two groups.

RESULTS

HbA_1c reduction from baseline was greater in the mDiabetes group (-0.40 ± 0.09%, n = 90) than in the pLogbook group (-0.06 ± 0.10%, n = 82). The difference of adjusted mean changes was 0.35% (95% CI 0.14-0.55, P = 0.001). The proportion of patients whose HbA_1c fell below 7.0% (53 mmol/mol) was 41.1% for the mDiabetes group and 20.7% for the pLogbook group (odds ratio [OR] 2.01, 95% CI 1.24-3.25, P = 0.003). The percentage of patients who attained HbA_1c levels below 7.0% (53 mmol/mol) without hypoglycemia was 31.1% in the mDiabetes group and 17.1% in the pLogbook group (OR 1.82, 95% CI 1.03-3.21, P = 0.024). There was no difference in the event numbers of severe hyperglycemia and hypoglycemia between the two groups.

CONCLUSIONS

The implementation of the mDiabetes for patients with inadequately controlled type 2 diabetes resulted in a significant reduction in HbA_1c levels, with tolerable safety profiles.

Moderating Effect of Insulin Resistance on the Relationship between Gray Matter Volumes and Cognitive Function

Background: It is controversial whether exposure to insulin resistance accelerates cognitive deterioration. The present study aimed to investigate the association between insulin resistance and gray matter volume loss to predict the cognitive decline. Methods: We recruited 160 participants (78 with Alzheimer’s disease and 82 without Alzheimer’s disease). Insulin resistance, regional gray matter volume, and cognitive function were assessed. A hierarchical moderated multiple regression (MMR) model was used to determine any associations among insulin resistance, structural changes in the brain, and cognitive decline. Results: The volumes of 7 regions in the gray matter were negatively related to insulin resistance in Alzheimer’s disease (p =0.032). Hierarchical MMR analysis indicated that insulin resistance did not directly affect the cognitive decline but moderated the cognitive decline through the decrease in gray matter volume in the key brain regions, i.e., inferior orbitofrontal gyrus (left), middle cingulate gyrus (right), hippocampus (right), and precuneus (right) (p < 0.05 in each case). Conclusion: Insulin resistance appears to exacerbate the cognitive decline associated with several gray matter volume loss.

Efficacy and tolerability of novel triple combination therapy in drug-naïve patients with type 2 diabetes from the TRIPLE-AXEL trial: protocol for an open-label randomised controlled trial

INTRODUCTION

Patients with type 2 diabetes are at risk of microvascular and macrovascular complications. Intensive glycaemic control, especially in patients with short duration of diabetes, is the mainstay of management of type 2 diabetes to lower the risk of complications. However, despite the improvement in the understanding of the pathophysiology of type 2 diabetes and development of novel glucose-lowering agents, long-term durable glycaemic control remains a difficult goal to achieve. Several challenging clinical trials proved that an early combination therapy with a variety of glucose-lowering agents had a more favourable effect than conventional stepwise therapy in terms of glycaemic control. We aim to evaluate the efficacy and tolerability of a novel, initial triple combination therapy with metformin, sodium glucose cotransporter 2 inhibitor (dapagliflozin) and dipeptidyl peptidase-4 inhibitor (saxagliptin) compared with conventional stepwise add-on therapy in drug-naïve patients with recent-onset type 2 diabetes.

METHODS AND ANALYSIS

This study is a multicentre, prospective, randomised, open-label, parallel group, comparator-controlled trial. A total of 104 eligible participants will be randomised to either the initial combination therapy group or the conventional stepwise add-on therapy group for 104 weeks. The primary endpoint is the proportion of patients who achieved haemoglobin A1c level<6.5% without hypoglycaemia, weight gain or discontinuation due to adverse events at 104 weeks. This trial will determine whether a novel triple combination therapy with metformin, dapagliflozin and saxagliptin has a beneficial effect on durable glycaemic control compared with conventional therapy in drug-naïve patients with type 2 diabetes.

ETHICS AND DISSEMINATION

This study protocol was approved by the local institutional review boards and independent ethics committees over the recruitment sites. Results of this study will be disseminated in scientific journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT02946632; Pre-results.

Nonsynonymous Variants in PAX4 and GLP1R Are Associated With Type 2 Diabetes in an East Asian Population

We investigated ethnicity-specific exonic variants of type 2 diabetes (T2D) and its related clinical phenotypes in an East Asian population. We performed whole-exome sequencing in 917 T2D case and control subjects, and the findings were validated by exome array genotyping in 3,026 participants. In silico replication was conducted for seven nonsynonymous variants in an additional 13,122 participants. Single-variant and gene-based association tests for T2D were analyzed. A total of 728,838 variants were identified by whole-exome sequencing. Among nonsynonymous variants, PAX4 Arg192His increased risk of T2D and GLP1R Arg131Gln decreased risk of T2D in genome-wide significance (odds ratio [OR] 1.48, P = 4.47 × 10^-16 and OR 0.84, P = 3.55 × 10^-8, respectively). Another variant at PAX4 192 codon Arg192Ser was nominally associated with T2D (OR 1.62, P = 5.18 × 10^-4). In T2D patients, PAX4 Arg192His was associated with earlier age at diagnosis, and GLP1R Arg131Gln was associated with decreased risk of cardiovascular disease. In control subjects without diabetes, the PAX4 Arg192His was associated with higher fasting glucose and GLP1R Arg131Gln was associated with lower fasting glucose and HbA_1c level. Gene-based analysis revealed that SLC30A8 was most significantly associated with decreased risk of T2D (P = 1.0 × 10^-4). In summary, we have identified nonsynonymous variants associated with risk of T2D and related phenotypes in Koreans.

Improvement of Glycosylated Hemoglobin in Patients with Type 2 Diabetes Mellitus under Insulin Treatment by Reimbursement for Self-Monitoring of Blood Glucose

BACKGROUND

In Korea, the costs associated with self-monitoring of blood glucose (SMBG) for patients with type 2 diabetes mellitus (T2DM) under insulin treatment have been reimbursed since November 2015. We investigated whether this new reimbursement program for SMBG has improved the glycemic control in the beneficiaries of this policy.

METHODS

Among all adult T2DM patients with ≥3 months of reimbursement (n=854), subjects without any changes in anti-hyperglycemic agents during the study period were selected. The improvement of glycosylated hemoglobin (HbA1c) was defined as an absolute reduction in HbA1c ≥0.6% or an HbA1c level at follow-up <7%.

RESULTS

HbA1c levels significantly decreased from 8.5%±1.3% to 8.2%±1.2% during the follow-up (P<0.001) in all the study subjects (n=409). Among them, 35.5% (n=145) showed a significant improvement in HbA1c. Subjects covered under the Medical Aid system showed a higher prevalence of improvement in HbA1c than those with medical insurance (52.2% vs. 33.3%, respectively, P=0.012). In the improvement group, the baseline HbA1c (P<0.001), fasting C-peptide (P=0.016), and daily dose of insulin/body weight (P=0.024) showed significant negative correlations with the degree of HbA1c change. Multivariate analysis showed that subjects in the Medical Aid system were about 2.5-fold more likely to improve in HbA1c compared to those with medical insurance (odds ratio, 2.459; 95% confidence interval, 1.138 to 5.314; P=0.022).

CONCLUSION

The reimbursement for SMBG resulted in a significant improvement in HbA1c in T2DM subjects using insulin, which was more prominent in subjects with poor glucose control at baseline or covered under the Medical Aid system.

Insulin Resistance is Associated with Cognitive Decline Among Older Koreans with Normal Baseline Cognitive Function: A Prospective Community-Based Cohort Study

We evaluated whether metabolic factors were associated with cognitive decline, compared to baseline cognitive function, among geriatric population. The present study evaluated data from an ongoing prospective community-based Korean cohort study. Among 1,387 participants who were >65 years old, 422 participants were evaluated using the Korean mini-mental status examination (K-MMSE) at the baseline and follow-up examinations. The mean age at the baseline was 69.3 ± 2.9 years, and 222 participants (52.6%) were men. The mean duration of education was 7.1 ± 3.6 years. During a mean follow-up of 5.9 ± 0.1 years, the K-MMSE score significantly decreased (−1.1 ± 2.7 scores), although no significant change was observed in the homeostasis model assessment of insulin resistance (HOMA-IR) value. Participants with more decreased percent changes in K-MMSE scores had a shorter duration of education (p = 0.001), older age (p = 0.022), higher baseline K-MMSE score (p < 0.001), and increased insulin resistance (∆HOMA-IR, p = 0.002). The correlation between the percent changes in K-MMSE and ∆HOMA-IR values remained significant after multivariable adjustment (B = −0.201, p = 0.002). During a 6-year follow-up of older Koreans with normal baseline cognitive function, increased insulin resistance was significantly correlated with decreased cognitive function.

Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus: A Position Statement of the Korean Diabetes Association

The glucagon-like peptide-1 receptor agonists (GLP-1RAs) were recommended as a monotherapy or combination therapy with oral hypoglycemic agents or basal insulin in the position statement of the Korean Diabetes Association 2017 for pharmacological therapy. Many randomized clinical trials and systematic reviews report that GLP-1RAs have considerable glucose-lowering effect and lead to weight reduction and low risk of hypoglycemia when used as a monotherapy or combination therapy. The cardiovascular safety of GLP-1RAs has been assessed in several randomized clinical trials and systematic reviews. The results of cardiovascular outcome trials of long-acting GLP-1RAs (liraglutide, semaglutide) demonstrated cardiovascular benefits in subjects with type 2 diabetes mellitus and a high risk of cardiovascular disease. The GLP-1RA may be a choice of therapy when weight control and avoidance of hypoglycemia are important, and patients with high risk of cardiovascular disease might also favor choosing GLP-1RA.

Insulin therapy for adult patients with type 2 diabetes mellitus: a position statement of the Korean Diabetes Association, 2017

The Korean Diabetes Association (KDA) has regularly updated its Clinical Practice Guidelines. In 2017, the KDA published a position statement on the use of antihyperglycemic agents for patients with type 2 diabetes mellitus (T2DM). Growing evidence from new multinational clinical trials using novel and traditional insulin analogues has also been accumulated. Following global trends, many results of clinical trials, especially concerning the clinical efficacy and safety of insulin therapy, have been published about Korean patients with T2DM. After a systematic search of recent evidence, the KDA updated and modified its clinical practice recommendations regarding the initiation, choice, and intensification of insulin and created an insulin treatment algorithm for the first time to guide physicians caring for adult Korean patients with T2DM.

Antihyperglycemic agent therapy for adult patients with type 2 diabetes mellitus 2017: a position statement of the Korean Diabetes Association

In 2017, the Korean Diabetes Association (KDA) published a position statement on the use of antihyperglycemic agents for patients with type 2 diabetes mellitus (T2DM). The KDA regularly updates its Clinical Practice Guidelines, but since the last update in 2015, many results from clinical trials have been introduced, and domestic data from studies performed in Korean patients with T2DM have been published. Recently, evidence from large clinical studies assessing cardiovascular outcomes following the use of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists in patients with T2DM were incorporated into the recommendations. Additionally, new data from clinical trials using dipeptidyl peptidase 4 inhibitors and thiazolidinediones in Korean patients with T2DM were added. Following a systematic review and assessment of recent evidence, the KDA updated and modified its clinical practice recommendations regarding the use of antihyperglycemic agents and revised the treatment algorithm for Korean adult patients with T2DM.

Monotherapy in patients with type 2 diabetes mellitus

In order to improve the quality of life and to prevent chronic complications related to diabetes mellitus, intensive lifestyle modification and proper medication are needed from the early stage of diagnosis of type 2 diabetes mellitus (T2DM). When using the first medication for diabetic patients, the appropriate treatment should be selected considering the clinical characteristics of the patient, efficacy of the drug, side effects, and cost. In general, the use of metformin as the first treatment for oral hypoglycemic monotherapy is recommended because of its excellent blood glucose-lowering effect, relatively low side effects, long-term proven safety, low risk of hypoglycemia, and low weight gain. If metformin is difficult to use as a first-line treatment, other appropriate medications should be selected in view of the clinical situation. If the goal of achieving glycemic control is not achieved by monotherapy, a combination therapy with different mechanisms of action should be initiated promptly.

Combination therapy of oral hypoglycemic agents in patients with type 2 diabetes mellitus

The Korean Diabetes Association (KDA) recently updated the Clinical Practice Guidelines on antihyperglycemic agent therapy for adult patients with type 2 diabetes mellitus (T2DM). In combination therapy of oral hypoglycemic agents (OHAs), general recommendations were not changed from those of the 2015 KDA guidelines. The Committee on Clinical Practice Guidelines of the KDA has extensively reviewed and discussed the results of meta-analyses and systematic reviews of effectiveness and safety of OHAs and many clinical trials on Korean patients with T2DM for the update of guidelines. All OHAs were effective when added to metformin or metformin and sulfonylurea, although the effects of each agent on body weight and hypoglycemia were different. Therefore, selection of a second agent as a metformin add-on therapy or third agent as a metformin and sulfonylurea add-on therapy should be based on the patient's clinical characteristics and the efficacy, side effects, mechanism of action, risk of hypoglycemia, effect on body weight, patient preference, and combined comorbidity. In this review, we address the results of meta-analyses and systematic reviews, comparing the effectiveness and safety among OHAs. It will help to choose the appropriate drug for an individual patient with T2DM.

Monotherapy in Patients with Type 2 Diabetes Mellitus

In order to improve the quality of life and to prevent chronic complications related to diabetes mellitus, intensive lifestyle modification and proper medication are needed from the early stage of diagnosis of type 2 diabetes mellitus (T2DM). When using the first medication for diabetic patients, the appropriate treatment should be selected considering the clinical characteristics of the patient, efficacy of the drug, side effects, and cost. In general, the use of metformin as the first treatment for oral hypoglycemic monotherapy is recommended because of its excellent blood glucose-lowering effect, relatively low side effects, long-term proven safety, low risk of hypoglycemia, and low weight gain. If metformin is difficult to use as a first-line treatment, other appropriate medications should be selected in view of the clinical situation. If the goal of achieving glycemic control is not achieved by monotherapy, a combination therapy with different mechanisms of action should be initiated promptly.

Antihyperglycemic Agent Therapy for Adult Patients with Type 2 Diabetes Mellitus 2017: A Position Statement of the Korean Diabetes Association

In 2017, the Korean Diabetes Association (KDA) published a position statement on the use of antihyperglycemic agents for patients with type 2 diabetes mellitus (T2DM). The KDA regularly updates its Clinical Practice Guidelines, but since the last update in 2015, many results from clinical trials have been introduced, and domestic data from studies performed in Korean patients with T2DM have been published. Recently, evidence from large clinical studies assessing cardiovascular outcomes following the use of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists in patients with T2DM were incorporated into the recommendations. Additionally, new data from clinical trials using dipeptidyl peptidase 4 inhibitors and thiazolidinediones in Korean patients with T2DM were added. Following a systematic review and assessment of recent evidence, the KDA updated and modified its clinical practice recommendations regarding the use of antihyperglycemic agents and revised the treatment algorithm for Korean adult patients with T2DM.

Insulin Therapy for Adult Patients with Type 2 Diabetes Mellitus: A Position Statement of the Korean Diabetes Association, 2017

The Korean Diabetes Association (KDA) has regularly updated its Clinical Practice Guidelines. In 2017, the KDA published a position statement on the use of antihyperglycemic agents for patients with type 2 diabetes mellitus (T2DM). Growing evidence from new multinational clinical trials using novel and traditional insulin analogues has also been accumulated. Following global trends, many results of clinical trials, especially concerning the clinical efficacy and safety of insulin therapy, have been published about Korean patients with T2DM. After a systematic search of recent evidence, the KDA updated and modified its clinical practice recommendations regarding the initiation, choice, and intensification of insulin and created an insulin treatment algorithm for the first time to guide physicians caring for adult Korean patients with T2DM.

Combination Therapy of Oral Hypoglycemic Agents in Patients with Type 2 Diabetes Mellitus

The Korean Diabetes Association (KDA) recently updated the Clinical Practice Guidelines on antihyperglycemic agent therapy for adult patients with type 2 diabetes mellitus (T2DM). In combination therapy of oral hypoglycemic agents (OHAs), general recommendations were not changed from those of the 2015 KDA guidelines. The Committee on Clinical Practice Guidelines of the KDA has extensively reviewed and discussed the results of meta-analyses and systematic reviews of effectiveness and safety of OHAs and many clinical trials on Korean patients with T2DM for the update of guidelines. All OHAs were effective when added to metformin or metformin and sulfonylurea, although the effects of each agent on body weight and hypoglycemia were different. Therefore, selection of a second agent as a metformin add-on therapy or third agent as a metformin and sulfonylurea add-on therapy should be based on the patient's clinical characteristics and the efficacy, side effects, mechanism of action, risk of hypoglycemia, effect on body weight, patient preference, and combined comorbidity. In this review, we address the results of meta-analyses and systematic reviews, comparing the effectiveness and safety among OHAs. It will help to choose the appropriate drug for an individual patient with T2DM.

Outcomes analysis of surgical and medical treatments for patients with primary aldosteronism

Patients with aldosterone-producing adenomas are treated using surgery, and patients with idiopathic hyperaldosteronism receive medical treatment using mineralocorticoid receptor antagonists (MRAs). However, the outcomes of surgical and medical treatment for primary aldosteronism (PA) remain unclear. Therefore, we compared the outcomes of surgical and medical treatment for PA and aimed to identify a specific subgroup that might benefit from medical treatment. We identified 269 patients who were treated for PA (unilateral excess: 221 cases; bilateral excess: 48 cases) during 2000-2015 at the Seoul National University Hospital and two other tertiary centers. The main outcomes were the amelioration of hypertension and hypokalemia. Treatment improved hypertension in the surgical treatment group (78.2%) and the medical treatment group (55.6%) (p = 0.001). At the last follow-up, hypokalemia was normalized in the surgical treatment group (97.1%) and the medical treatment group (93.7%, p = 0.046). Among patients with unilateral aldosterone excess, surgery provided advantages in resolving hypertension without worsening renal function. Among patients who were >60 years old or had impaired renal function, surgical and medical treatment provided similar amelioration of hypokalemia and hypertension. Three patients developed hyperkalemia after surgery, and no patients developed hyperkalemia after initiating medical treatment. The surgical treatment group exhibited a lower postoperative estimated glomerular filtration rate (eGFR) and higher serum potassium levels, compared to the medical treatment group. Surgical treatment provided better hypertension and hypokalemia outcomes among patients with PA, compared to medical treatment. However, MRAs may be appropriate for elderly patients with impaired renal function.

Efficacy of Moderate Intensity Statins in the Treatment of Dyslipidemia in Korean Patients with Type 2 Diabetes Mellitus

BACKGROUND

There has been evidences of ethnic differences in the low density lipoprotein cholesterol (LDL-C) lowering effect of statin. We aimed to evaluate the efficacy of moderate-intensity statins in the treatment of dyslipidemia among Korean patients with type 2 diabetes mellitus (T2DM).

METHODS

We analyzed a retrospective cohort that consisted of Korean patients with T2DM aged 40 to 75 years who had been prescribed any of the moderate-intensity statins (atorvastatin 10 or 20 mg, rosuvastatin 5 or 10 mg, pitavastatin 2 mg, or pravastatin 40 mg). Among them, only patients with baseline lipid profiles before starting statin treatment were selected, and changes in their lipid profiles before and 6 months after statin therapy were analyzed.

RESULTS

Following the first 6 months of therapy, the overall LDL-C reduction was -47.4% (interquartile range, -56.6% to -34.1%). In total, 92.1% of the participants achieved an LDL-C level of <100 mg/dL, 38.3% had a 30% to 50% reduction in their LDL-C levels, and 42.3% had a reduction in their LDL-C levels greater than 50%. The response rates of each drug for achieving a LDL-C level <100 mg/dL were 81.7%, 93.1%, 95.0%, 95.0%, 96.5%, and 91.7% for treatment with atorvastatin doses of 10 or 20 mg, rosuvastatin 5 or 10 mg, pitavastatin 2 mg, and pravastatin 40 mg, respectively.

CONCLUSION

In conclusion, the use of moderate-intensity statins reduced LDL-C levels less than 100 mg/dL in most of the Korean patients studied with T2DM. The efficacies of those statins were higher than expected in about 42% of Korean patients with T2DM.

Efficacy and safety of initial combination therapy with gemigliptin and metformin compared with monotherapy with either drug in patients with type 2 diabetes: A double-blind randomized controlled trial (INICOM study)

BACKGROUND

Gemigliptin is a new dipeptidyl peptidase-IV inhibitor. We investigated the efficacy and safety of initial combination therapy with gemigliptin and metformin compared with monotherapy with either drug in patients with type 2 diabetes (T2D).

METHODS

A total of 433 T2D patients with a glycosylated haemoglobin (HbA1c) level of 7.5% to 11.0% and a fasting plasma glucose (FPG) concentration <270 mg/dL were randomly assigned to 3 groups: (1) gemigliptin 50 mg qd + metformin 1000 to 2000 mg qd (titrated individually), (2) gemigliptin 50 mg qd, or (3) metformin 1000 to 2000 mg qd. The primary end-point was the change in HbA1c level after 24 weeks. Secondary end-points were the changes in FPG, insulin, proinsulin and C-peptide levels. The percentages of responders who achieved an HbA1c level <7% (or <6.5%) were compared between treatment groups.

RESULTS

Baseline HbA1c levels were 8.7% in all groups. The mean changes in HbA1c level from baseline to week 24 were -2.06%, -1.24% and -1.47% in the combination, gemigliptin monotherapy and metformin monotherapy groups, respectively. The 95% confidence intervals for between-group differences in HbA1c changes were -1.02 to -0.63 in the combination group vs the gemigliptin group and -0.82 to -0.41 vs the metformin group, which confirmed the superiority of combination therapy. A significantly higher percentage of patients in the combination therapy group reached the target HbA1c level <7% (or <6.5%) compared with the monotherapy groups. No severe side effects were observed.

CONCLUSIONS

In T2D patients, the initial combination of gemigliptin and metformin had superior efficacy without safety concerns compared with monotherapy with either drug.

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.

Experimental results from an X-ray imaging crystal spectrometer utilizing multi-wire proportional counter for KSTAR

The inconsistency of the first experimental results from the X-ray imaging crystal spectrometer for the Korea Superconducting Tokamak Advanced Research device utilizing a multi-wire proportional counter (MWPC) is clarified after improving the photon-count rate of the data acquisition system for the MWPC and ground loop isolator for the whole spectrometer system. The improved MWPC is successfully applied to pure Ohmic plasmas as well as plasmas with high confinement modes.