Prospective randomized comparative study of the effect of pemafibrate add-on or double statin dose on small dense low-density lipoprotein-cholesterol in patients with type 2 diabetes and hypertriglyceridemia on statin therapy.

AIMS/INTRODUCTION: Small dense low-density lipoprotein (sdLDL) is a more potent atherogenic lipoprotein than LDL. As sdLDL-cholesterol (C) levels are determined by triglyceride and LDL-C levels, pemafibrate and statins can reduce sdLDL-C levels. However, it remains unclear whether adding pemafibrate or increasing statin doses would more effectively reduce sdLDL-C levels in patients receiving statin therapy. MATERIALS AND METHODS: A total of 97 patients with type 2 diabetes and hypertriglyceridemia who were treated with statins were randomly assigned to the pemafibrate 0.2 mg/day addition or statin dose doubled, and followed for 12 weeks. sdLDL-C was measured by our established homogenous assay. RESULTS: The percentage and absolute reductions of sdLDL-C levels were significantly greater in the pemafibrate add-on group than the statin doubling group (-32.8 vs -8.1%; -16 vs -3 mg/dL, respectively). Triglyceride levels were reduced only in the pemafibrate add-on group (-44%), and LDL-C levels were reduced only in the statin doubling group (-8%), whereas levels of non-high-density lipoprotein-C and apolipoprotein B were similarly decreased (7-9%) in both groups. The absolute reductions of sdLDL-C levels were closely associated with decreased triglyceride, LDL-C, non-high-density lipoprotein-C and apolipoprotein B. In the subgroup analysis, the effect of pemafibrate add-on on sdLDL-C reductions was observed irrespective of baseline lipid parameters or statin type. No serious adverse effects were observed in both groups. CONCLUSIONS: In patients with type 2 diabetes and hypertriglyceridemia, the addition of pemafibrate to a statin is superior to doubling a statin in reducing sdLDL-C without increasing adverse effects.

Efficacy of a new enzyme-linked immunosorbent assay system for three islet cell autoantibodies in Japanese patients with acute-onset type 1 diabetes.

To evaluate the clinical efficacy of a new enzyme-linked immunosorbent assay (ELISA) system for simultaneously detecting three islet cell autoantibodies against glutamic acid decarboxylase (GADA), insulinoma-associated antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A) (3 Screen ICA ELISA) in Japanese patients with acute-onset type 1 diabetes (T1D). In addition, clinical factors affecting the 3 Screen ICA ELISA index were investigated. We compared the positivity values of 3 Screen ICA ELISA with that of each autoantibody alone in 97 patients with acute-onset T1D (mean age 48.7 years, 49% male) and 100 non-diabetic subjects (mean age 47.0 years, 50% male). Serum thyroid stimulating hormone receptor antibody, thyroid peroxidase antibody (TPOAb) and thyroglobulin autoantibody levels were also evaluated. The cut-off value of the 3 Screen ICA ELISA was determined based on the 97th percentile of 100 non-diabetic controls (threshold for positivity, ≥14 index). The mean age of disease onset and duration of diabetes were 34.2 years and 14.5 years, respectively. Among all T1D patients, the positivity of 3 Screen ICA ELISA was 71.1%, while that of GADA, IA-2A, and ZnT8A were 59.8%, 25.8%, and 25.8%, respectively. The median 3 Screen ICA index was 121.9 (8.7-468.2) and was associated with titers of each autoantibody, most so with GADA, and was significantly higher in TPOAb-positive patients than in TPOAb-negative patients. Our findings suggests that the 3 Screen ICA ELISA may be a time-saving diagnostic tool for evaluating islet autoantibodies in acute-onset T1D patients.

Association between insulin-like growth factor 1 and pancreatic volume in type 1 and type 2 diabetes: cross-sectional study of a Japanese population.

AIMS/HYPOTHESIS: Although IGF-1 is known to promote organ growth, including exocrine pancreas, the association between plasma IGF-1 levels and pancreatic size remains unclear in diabetic patients. METHODS: This cross-sectional study was designed to investigate the correlations among pancreatic volume (PV) based on computed tomography, IGF-1 levels, age- and sex-adjusted IGF-1 levels (IGF-1 Z-score), and C-peptide levels in patients with type 1 diabetes (T1D) (n = 51) and type 2 diabetes (T2D) (n = 104) in a Japanese population. RESULTS: PV was significantly correlated with body weight (BW) in both types of diabetes. PV adjusted for BW (PV/BW), IGF-1 Z-score and C-peptide levels were significantly lower in patients with T1D than T2D. There was a significant positive correlation between C-peptide levels and PV/BW in both subtypes of diabetes. IGF-1 Z-scores were significantly correlated with PV/BW in patients with T1D (r = 0.37, P = 0.007), but not T2D. Although IGF-1 Z-scores were not correlated with age, age of disease onset, disease duration, HbA1c, or C-peptide levels in both types of diabetes, a multivariable liner regression analysis revealed that IGF-1 Z-score and C-peptide levels were independent correlates of PV/BW in T1D patients, while C-peptide levels were a sole correlate in T2D. CONCLUSIONS/INTERPRETATION: Decreased IGF-1 levels might be one causal factor for smaller pancreas in patients with T1D.

Very rare case of Graves' disease with resistance to methimazole: a case report and literature review.

BACKGROUND: Methimazole (MMI) is used to treat hyperthyroidism in Graves' disease. It is rare to encounter patients in whom hyperthyroidism cannot be controlled using high doses of MMI.Case presentation: A 21-year-old woman was referred to our hospital because of MMI-resistant Graves' disease. Although her MMI dose had been increased to 120 mg/day, her serum thyroid hormone concentration was too high to be measured. Additional therapy with lithium carbonate, and then with dexamethasone and inorganic iodine, was initiated. After 14 days, the patient's serum thyroid hormone concentration normalized, while she was taking 150 mg/day MMI, 800 mg/day lithium carbonate, 6 mg/day dexamethasone and 306 mg/day inorganic iodine, and total thyroidectomy was then performed. The patient was discharged 8 days after the thyroidectomy and experienced no major complications. CONCLUSIONS: We have presented a rare case of Graves' disease that was resistant to high-dose MMI. Combination therapy of MMI with lithium carbonate, dexamethasone and inorganic iodine may represent a therapeutic option for the preoperative preparation of patients with MMI-resistant Graves' disease.

Glucose Variability is Independently Correlated with Serum Level of Pigment Epithelium-Derived Factor in Type 2 Diabetes.

INTRODUCTION: Pigment epithelium-derived factor (PEDF) may play a role in cardiometabolic disorders. The aim of this study was to investigate which biochemical and clinical parameters are independently associated with serum PEDF levels in patients with type 2 diabetes mellitus (T2DM). METHODS: We performed a cross-sectional analysis of 124 patients with T2DM who underwent continuous glucose monitoring (CGM) and blood chemistry analysis, including the diacron-reactive oxygen metabolites (d-ROMs) test and serum PEDF measurement (study 1). Then we investigated whether the changes in the studied biochemical and clinical parameters after 24 weeks of treatment (Δparameters) with anti-hyperglycemic agents, including sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide 1 receptor agonists, and/or insulin and anti-hypertensive drugs and statins, were independently correlated with change in PEDF (ΔPEDF) in 52 of the patients with T2DM for whom there was sufficient serum samples to perform the post-treatment analysis (study 2). Serum levels of PEDF were measured with an enzyme-linked immunosorbent assay. CGM metrics were calculated on days 2 and 3. Oxidative stress was evaluated using the d-ROMs test. RESULTS: Body mass index (BMI), triglycerides, fasting C-peptide, mean amplitude of glycemic excursions (MAGE), urinary albumin-to-creatinine ratio (UACR), and d-ROMs were positively associated with serum PEDF level, and high-density lipoprotein cholesterol (HDL-C) and estimated glomerular filtration rate (eGFR) were inversely associated with serum PEDF level. Because these parameters were correlated with each other, multivariate stepwise analysis was performed: eGFR, HDL-C, BMI, MAGE, and UACR remained significant (R2 = 0.452). Furthermore, ΔMAGE and Δd-ROMs were positively correlated with ΔPEDF in study 2. CONCLUSIONS: The results of this study suggest that MAGE may be independently correlated with elevations in serum PEDF level in patients with T2DM.

Glucose-dependent insulinotropic polypeptide inhibits cardiac hypertrophy and fibrosis in diabetic mice via suppression of TGF-ß2.

Diabetic cardiomyopathy is associated with an increased risk for heart failure and death in patients with diabetes. We investigated here whether and how GIP attenuated cardiac hypertrophy and fibrosis in diabetic mice with obesity. Diabetic db/db mice at 7 weeks old were infused with vehicle or GIP (50 nmol/kg/day) for 6 weeks, and hearts were collected for histological and RT-PCR analyzes. Cardiomyocytes isolated from neonatal mice were incubated with or without 300 nM [D-Ala2]-GIP, 30 mM glucose, or 100 µg/mL advanced glycation end products (AGEs) for RT-PCR and lucigenin assays. Compared with non-diabetic mice, diabetic mice exhibited larger left ventricle wall thickness and cardiomyocyte sizes and more fibrotic areas in association with up-regulation of myosin heavy chain ß (ß-Mhc) and transforming growth factor-beta2 (Tgf-ß2) mRNA levels, all of which were inhibited by GIP infusion. High glucose increased NADPH oxidase-driven superoxide generation and up-regulated ß-Mhc, Tgf-ß2, and receptor for AGEs mRNA levels in cardiomyocytes, and augmented the AGE-induced ß-Mhc gene expression. [D-Ala2]-GIP attenuated all of the deleterious effects of high glucose and/or AGEs on cardiomyocytes. Our present findings suggest that GIP could inhibit cardiac hypertrophy and fibrosis in diabetic mice via suppression of TGF-ß2.

AGE-RAGE Axis Stimulates Oxidized LDL Uptake into Macrophages through Cyclin-Dependent Kinase 5-CD36 Pathway via Oxidative Stress Generation.

Advanced glycation end products (AGEs) are localized in macrophage-derived foam cells within atherosclerotic lesions, which could be associated with the increased risk of atherosclerotic cardiovascular disease under diabetic conditions. Although foam cell formation of macrophages has been shown to be enhanced by AGEs, the underlying molecular mechanism remains unclear. Since cyclin-dependent kinase 5 (Cdk5) is reported to modulate inflammatory responses in macrophages, we investigated whether Cdk5 could be involved in AGE-induced CD36 gene expression and foam cell formation of macrophages. AGEs significantly increased Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and Cdk5 and CD36 gene expression in U937 human macrophages, all of which were inhibited by DNA aptamer raised against RAGE (RAGE-aptamer). Cdk5 and CD36 gene expression levels were correlated with each other. An antioxidant, N-acetyl-l-cysteine, mimicked the effects of RAGE-aptamer on AGE-exposed U937 cells. A selective inhibitor of Cdk5, (R)-DRF053, attenuated the AGE-induced Dil-ox-LDL uptake and CD36 gene expression, whereas anti-CD36 antibody inhibited the Dil-ox-LDL uptake but not Cdk5 gene expression. The present study suggests that AGEs may stimulate ox-LDL uptake into macrophages through the Cdk5-CD36 pathway via RAGE-mediated oxidative stress.

Anti-inflammatory and atheroprotective properties of glucagon.

Although glucagon has been shown to exert pleiotropic actions in various types of cells and organs through the interaction with its receptor, its pathophysiological role in atherosclerotic cardiovascular disease remains unclear. Here, we examined whether and how glucagon could attenuate the progression of atherosclerotic plaques in apolipoprotein E-deficient mice (ApoE-/-), an animal model of atherosclerosis. Glucagon (138 or 413 nmol/kg/day) or vehicle was infused to mice at 16 weeks of age. After 4-week treatment, vascular samples were collected for histological and RT-PCR analyses. Human monocytic THP-1 cells were pre-incubated with or without a glucagon receptor antagonist L-168049, and then treated with or without glucagon for 7 h. Gene and protein expressions were determined by RT-PCR and western blot analyses, respectively. High-dose glucagon infusion significantly decreased aortic plaque area and volume in ApoE-/- mice, both of which were inversely correlated with plasma glucagon levels. Glucagon infusion also reduced the ratio of pro-inflammatory interleukin-1ß to anti-inflammatory interleukin-10 gene expression in aortae. Glucagon receptor was expressed in THP-1 cells, and 1 nM glucagon decreased the ratio of interleukin-1ß to interleukin-10 gene expression, which was significantly prevented by L-168049. Our present findings suggest that glucagon could exert atheroprotection partly via its anti-inflammatory property.

A Dipeptidyl Peptidase-4 Inhibitor Inhibits Foam Cell Formation of Macrophages in Type 1 Diabetes via Suppression of CD36 and ACAT-1 Expression.

Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to play a protective role against atherosclerosis in both animal models and patients with type 2 diabetes (T2D). However, since T2D is associated with dyslipidemia, hypertension and insulin resistance, part of which are ameliorated by DPP-4 inhibitors, it remains unclear whether DPP-4 inhibitors could have anti-atherosclerotic properties directly by attenuating the harmful effects of hyperglycemia. Therefore, we examined whether a DPP-4 inhibitor, teneligliptin, could suppress oxidized low-density lipoprotein (ox-LDL) uptake, foam cell formation, CD36 and acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) gene expression of macrophages isolated from streptozotocin-induced type 1 diabetes (T1D) mice and T1D patients as well as advanced glycation end product (AGE)-exposed mouse peritoneal macrophages and THP-1 cells. Foam cell formation, CD36 and ACAT-1 gene expression of macrophages derived from T1D mice or patients increased compared with those from non-diabetic controls, all of which were inhibited by 10 nmol/L teneligliptin. AGEs mimicked the effects of T1D; teneligliptin attenuated all the deleterious effects of AGEs in mouse macrophages and THP-1 cells. Our present findings suggest that teneligliptin may inhibit foam cell formation of macrophages in T1D via suppression of CD36 and ACAT-1 gene expression partly by attenuating the harmful effects of AGEs.

Association of Hemoglobin A1c, 1,5-Anhydro-D-Glucitol and Glycated Albumin with Oxidative Stress in Type 2 Diabetes Mellitus Patients: A Cross-Sectional Study.

INTRODUCTION: Oxidative stress plays a central role in the development and progression of vascular complications in patients with type 2 diabetes mellitus (T2DM). We have previously shown that markers of glucose variability evaluated by continuous glucose monitoring (CGM) are positively associated with oxidative stress in patients with T2DM. However, the evaluation of the glycemic variability by CGM remains a time- and money-consuming procedure. Therefore, this study investigated the independent correlates of oxidative stress among various other clinical markers routinely measured in primary care. METHODS: This was a retrospective cross-sectional study with 234 T2DM patients to examine which clinical variables, including 1,5-anhydro-D-glucitol (1,5-AG) and glycated albumin (GA), were independently associated with oxidative stress. Oxidative stress was measured using the diacron-reactive oxygen metabolites (d-ROMs) test. The relationships between d-ROMs and clinical factors, such as blood glucose, glycated hemoglobin (HbA1c), 1,5-AG, GA, lipid parameters, and blood pressure, were examined. RESULTS: Multiple stepwise regression analysis revealed that 1,5-AG (inversely), GA, triglycerides, use of metformin and being female were independently associated with d-ROMs. When patients with T2DM were stratified into two groups with HbA1c < 8.0% and HbA1c ≥ 8.0%, 1,5-AG (inversely), HbA1c, use of metformin and being female were independently associated with d-ROMs in diabetes patients with HbA1c < 8.0%, whereas GA, fasting plasma glucose and being female were independently associated with d-ROMs in patients with HbA1c ≥ 8.0%. CONCLUSION: Our present study suggests that 1,5-AG and GA are the strongest correlates of oxidative stress in patients with well and poorly controlled T2DM, respectively.

Luseogliflozin attenuates neointimal hyperplasia after wire injury in high-fat diet-fed mice via inhibition of perivascular adipose tissue remodeling.

BACKGROUND: Excess fat deposition could induce phenotypic changes of perivascular adipose tissue (PVAT remodeling), which may promote the progression of atherosclerosis via modulation of adipocytokine secretion. However, it remains unclear whether and how suppression of PVAT remodeling could attenuate vascular injury. In this study, we examined the effect of sodium-glucose cotransporter 2 (SGLT2) inhibitor, luseogliflozin on PVAT remodeling and neointima formation after wire injury in mice. METHODS: Wilt-type mice fed with low-fat diet (LFD) or high-fat diet (HFD) received oral administration of luseogliflozin (18 mg/kg/day) or vehicle. Mice underwent bilateral femoral artery wire injury followed by unilateral removal of surrounding PVAT. After 25 days, injured femoral arteries and surrounding PVAT were analyzed. RESULTS: In LFD-fed lean mice, neither luseogliflozin treatment or PVAT removal attenuated the intima-to-media (I/M) ratio of injured arteries. However, in HFD-fed mice, luseogliflozin or PVAT removal reduced the I/M ratio, whereas their combination showed no additive reduction. In PVAT surrounding injured femoral arteries of HFD-fed mice, luseogliflozin treatment decreased the adipocyte sizes. Furthermore, luseogliflozin reduced accumulation of macrophages expressing platelet-derived growth factor-B (PDGF-B) and increased adiponectin gene expression. Gene expression levels of Pdgf-b in PVAT were correlated with the I/M ratio. CONCLUSIONS: Our present study suggests that luseogliflozin could attenuate neointimal hyperplasia after wire injury in HFD-fed mice partly via suppression of macrophage PDGF-B expression in PVAT. Inhibition of PVAT remodeling by luseogliflozin may be a novel therapeutic target for vascular remodeling after angioplasty.

Relationship between glucose variability evaluated by continuous glucose monitoring and clinical factors, including glucagon-stimulated insulin secretion in patients with type 2 diabetes.

AIMS: To evaluate the clinical factors affecting daily and day-to-day glucose variability by using continuous glucose monitoring. METHODS: We performed a cross-sectional analysis of patients with type 2 diabetes mellitus (T2DM) who underwent a glucagon stimulation test (GST) with 72 h of continuous glucose monitoring. Daily glucose variability was evaluated by mean amplitude of glycemic excursions [MAGE], percentage coefficient of variation for glucose (%CV), and day-to-day glucose variability (mean of daily differences [MODD]) by using continuous glucose monitoring. Correlations of clinical factors, including insulin secretion ability by the GST with MAGE, %CV, and MODD, were analyzed. RESULTS: In 83 T2DM with insulin therapy, age and hemoglobin A1c (HbA1c) correlated with MAGE and %CV, fasting plasma glucose with MAGE and MODD, and increment of C-peptide immunoreactivity (ΔCPR) by GST correlated inversely with MAGE, %CV, and MODD. In 126 T2DM without insulin therapy, age, diastolic blood pressure, and triglycerides correlated with MODD, HbA1c with MAGE and MODD, and ΔCPR inversely correlated with %CV. Use of α-glucosidase inhibitors inversely correlated with %CV, whereas that of sulfonylurea was associated with MAGE and %CV. CONCLUSIONS: These results suggest that ΔCPR correlated with stability of glycemic control, whereas poorly controlled diabetes is associated with increase in glucose variability. α-glucosidase inhibitors may be superior to sulfonylureas in reducing the glucose variability in T2DM.

Nesfatin-1 suppresses peripheral arterial remodeling without elevating blood pressure in mice.

Nesfatin-1 is a novel anorexic peptide hormone that also exerts cardiovascular protective effects in rodent models. However, nesfatin-1 treatment at high doses also exerts vasopressor effects, which potentially limits its therapeutic application. Here, we evaluated the vasoprotective and vasopressor effects of nesfatin-1 at different doses in mouse models. Wild-type mice and those with the transgene nucleobindin-2, a precursor of nesfatin-1, were employed. Wild-type mice were randomly assigned to treatment with vehicle or nesfatin-1 at 0.2, 2.0 or 10 µg/kg/day (Nes-0.2, Nes-2, Nes-10, respectively). Subsequently, mice underwent femoral artery wire injury to induce arterial remodeling. After 4 weeks, injured arteries were collected for morphometric analysis. Compared with vehicle, nesfatin-1 treatments at 2.0 and 10 µg/kg/day decreased body weights and elevated plasma nesfatin-1 levels with no changes in systolic blood pressure. Furthermore, these treatments reduced neointimal hyperplasia without inducing undesirable remodeling in injured arteries. However, nesfatin-1 treatment at 0.2 µg/kg/day was insufficient to elevate plasma nesfatin-1 levels and showed no vascular effects. In nucleobindin-2-transgenic mice, blood pressure was slightly higher but neointimal area was lower than those observed in littermate controls. In cultured human vascular endothelial cells, nesfatin-1 concentration-dependently increased nitric oxide production. Additionally, nesfatin-1 increased AMP-activated protein kinase phosphorylation, which was abolished by inhibiting liver kinase B1. We thus demonstrated that nesfatin-1 treatment at appropriate doses suppressed arterial remodeling without affecting blood pressure. Our findings indicate that nesfatin-1 can be a therapeutic target for improved treatment of peripheral artery disease.

Antiatherogenic effects of liraglutide in hyperglycemic apolipoprotein E-null mice via AMP-activated protein kinase-independent mechanisms.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert potent glucose-lowering effects without increasing risks for hypoglycemia and weight gain. Preclinical studies have demonstrated direct antiatherogenic effects of GLP-1RAs in normoglycemic animal models; however, the underlying mechanisms in hyperglycemic conditions have not been fully clarified. Here we aimed to elucidate the role of AMP-activated protein kinase (AMPK) in antiatherogenic effects of GLP-1RAs in hyperglycemic mice. Streptozotocin-induced hyperglycemic apolipoprotein E-null mice were treated with vehicle, low-dose liraglutide (17 nmol·kg-1·day-1), or high-dose liraglutide (107 nmol·kg-1·day-1) in experiment 1 and the AMPK inhibitor dorsomorphin, dorsomorphin + low-dose liraglutide, or dorsomorphin + high-dose liraglutide in experiment 2. Four weeks after treatment, aortas were collected to assess atherosclerosis. In experiment 1, metabolic parameters were similar among the groups. Assessment of atherosclerosis revealed that high-dose liraglutide treatments reduced lipid deposition on the aortic surface and plaque volume and intraplaque macrophage accumulation at the aortic sinus. In experiment 2, liraglutide-induced AMPK phosphorylation in the aorta was abolished by dorsomorphin; however, the antiatherogenic effects of high-dose liraglutide were preserved. In cultured human umbilical vein endothelial cells, liraglutide suppressed tumor necrosis factor-induced expression of proatherogenic molecules; these effects were maintained under small interfering RNA-mediated knockdown of AMPKα1 and in the presence of dorsomorphin. Conversely, in human monocytic U937 cells, the anti-inflammatory effects of liraglutide were abolished by dorsomorphin. In conclusion, liraglutide exerted AMPK-independent antiatherogenic effects in hyperlipidemic mice with streptozotocin-induced hyperglycemia, with the possible involvement of AMPK-independent suppression of proatherogenic molecules in vascular endothelial cells.

Emphysematous cystitis in an elderly Japanese patient with type 2 diabetes mellitus.

We report a rare but fatal case of emphysematous cystitis (EC) that presented as a typical image of gas bubbles within the urinary bladder wall on computed tomography (CT). This disease has a high mortality rate more than that reported previously based on recent literature review in Japan.

Pheochromocytoma presenting with severe hyperglycemia and metabolic acidosis following intra-articular glucocorticoid administration: a case report.

BACKGROUND: There are several reports of pheochromocytoma crisis triggered by systemic glucocorticoid administration. However, pheochromocytoma crisis after intra-articular glucocorticoid administration has been rarely reported. CASE PRESENTATION: A 45-year-old Japanese man presented to our hospital with a sudden, severe headache. He had no history of diabetes. He had received an intra-articular injection of betamethasone (2 mg) for joint pain, 2 days prior to his admission. On examination, his blood pressure was 240/126 mmHg and pulse was 120 beats/minute. The possibility of cerebrovascular events was ruled out by imaging studies and lumbar puncture. Blood tests revealed severe hyperglycemia (523 mg/dL) and metabolic acidosis (pH 7.21, anion gap 26.2 mEq/L, lactate 11.75 mmol/L) with a glycosylated hemoglobin level of 5.7%. Although a urine sample could not be obtained, fulminant type 1 diabetes mellitus and diabetic ketoacidosis were suspected based on these findings. However, after the initial treatment for diabetic ketoacidosis, his insulin secretion was found to be normal and the plasma levels of ketones were not elevated. This excluded the possibility of fulminant type 1 diabetes mellitus and diabetic ketoacidosis. Subsequently, a left adrenal gland tumor and elevated levels of serum catecholamine and urinary catecholamine metabolites were detected, while his other hormone levels were normal. Serum catecholamine levels did not decrease following the clonidine test, and a functional scintigraphy using iodine-131 metaiodobenzylguanidine showed strong uptake in the region of the left adrenal gland. Although no signs of pheochromocytoma crisis, such as paroxysmal hyperglycemia and hypertension, had been observed since admission, a pheochromocytoma was diagnosed based on the investigations. After controlling his blood pressure, a left adrenalectomy was performed. CONCLUSIONS: This case illustrates that intra-articular glucocorticoid administration can induce a pheochromocytoma crisis and an increase in hyperglycemia, and that pheochromocytoma crisis can resemble the clinical picture of fulminant type 1 diabetes mellitus owing to severe hyperglycemia with metabolic acidosis and normal glycosylated hemoglobin levels, especially under the influence of glucocorticoid.

Glucose-Dependent Insulinotropic Polypeptide Suppresses Peripheral Arterial Remodeling in Male Mice.

Glucose-dependent insulinotropic polypeptide (GIP) exhibits direct cardiovascular actions in addition to its well-known insulinotropic effect. However, the role of GIP in peripheral artery disease remains unclear. In this study, we evaluated the effects of GIP against peripheral arterial remodeling in mouse models. The genetic deletion of GIP receptor (GIPR) led to exaggerated neointimal hyperplasia after transluminal femoral artery wire injury. Conversely, chronic GIP infusion suppressed neointimal hyperplasia and facilitated endothelial regeneration. The beneficial effects of GIP were abrogated by inhibiting nitric oxide (NO) synthase, suggesting a possible mechanism mediated by NO. In cultured human umbilical vein endothelial cells (HUVECs), GIP elevated cytosolic calcium levels without affecting intracellular cAMP levels. Furthermore, GIP dose-dependently increased NO production, whereas this effect was abolished by inhibiting AMP-activated protein kinase (AMPK). GIP induced AMPK phosphorylation, which was abrogated by inhibiting phospholipase C and calcium-calmodulin-dependent protein kinase kinase but not by adenylate cyclase or liver kinase B1, suggesting the existence of a calcium-mediated GIPR signaling pathway. These effects of GIP were retained in severe hyperglycemic Leprdb/ Leprdb mice and in high-glucose-cultured HUVECs. Overall, we demonstrated the protective effects of GIP against peripheral arterial remodeling as well as the involvement of a calcium-mediated GIPR signaling pathway in vascular endothelial cells. Our findings imply the potential vascular benefits of multiple agonists targeting G protein-coupled receptors, including GIPR, which are under development for the treatment of type 2 diabetes.

A Dipeptidyl Peptidase-4 Inhibitor Suppresses Macrophage Foam Cell Formation in Diabetic db/db Mice and Type 2 Diabetes Patients.

Dipeptidyl peptidase-4 (DPP-4) inhibitors could have antiatherosclerotic action, in addition to antihyperglycemic roles. Because macrophage foam cells are key components of atherosclerosis, we investigated the effect of the DPP-4 inhibitor teneligliptin on foam cell formation and its related gene expression levels in macrophages extracted from diabetic db/db (C57BLKS/J Iar -+Leprdb/+Leprdb ) mice and type 2 diabetes (T2D) patients ex vivo. We incubated mouse peritoneal macrophages and human monocyte-derived macrophages differentiated by 7-day culture with oxidized low-density lipoprotein in the presence/absence of teneligliptin (10 nmol/L) for 18 hours. We observed remarkable suppression of foam cell formation by teneligliptin treatment ex vivo in macrophages isolated from diabetic db/db mice (32%) and T2D patients (38%); this effect was accompanied by a reduction of CD36 (db/db mice, 43%; T2D patients, 46%) and acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) gene expression levels (db/db mice, 47%; T2D patients, 45%). Molecular mechanisms underlying this effect are associated with downregulation of CD36 and ACAT-1 by teneligliptin. The suppressive effect of a DPP-4 inhibitor on foam cell formation in T2D is conserved across species and is worth studying to elucidate its potential as an intervention for antiatherogenesis in T2D patients.

The role of endothelial nitric oxide in the anti-restenotic effects of liraglutide in a mouse model of restenosis.

BACKGROUND: Previous animal studies have shown that glucagon-like peptide-1 receptor agonists (GLP-1RAs) suppress arterial restenosis, a major complication of angioplasty, presumably through their direct action on vascular smooth muscle cells. However, the contribution of vascular endothelial cells (VECs) to this process remains unknown. In addition, the potential interference caused by severe hyperglycemia and optimal treatment regimen remain to be determined. METHODS: Nine-week-old male C57BL6 (wild-type) and diabetic db/db mice were randomly divided into vehicle or liraglutide treatment groups (Day 1), and subject to femoral artery wire injuries (Day 3). The injured arteries were collected on Day 29 for morphometric analysis. Human umbilical vein endothelial cells (HUVECs) were used for in vitro experiments. One-way ANOVA, followed by Tukey's test, was used for comparisons. RESULTS: In wild-type mice, liraglutide treatment (5.7, 17, or 107 nmol/kg/day) dose-dependently reduced the neointimal area (20, 50, and 65%) without inducing systemic effects, and caused an associated decrease in the percentage of vascular proliferating cells. However, these effects were completely abolished by the nitric oxide synthase (NOS) inhibitor N-omega-nitro-L-arginine methyl ester. Next, we investigated the optimal treatment regimen. Early treatment (Days 1-14) was as effective in reducing the neointimal area and vascular cell proliferation as full treatment (Days 1-29), whereas delayed treatment (Days 15-29) was ineffective. In HUVECs, liraglutide treatment dose-dependently stimulated NO production, which was dependent on GLP-1R, cAMP, cAMP-dependent protein kinase, AMP-activated protein kinase (AMPK), and NOS. Subsequently, we investigated the role of liver kinase B (LKB)-1 in this process. Liraglutide increased the phosphorylation of LKB-1, and siRNA-induced LKB-1 knockdown abolished liraglutide-stimulated NO production. In severe hyperglycemic db/db mice, liraglutide treatment also suppressed neointimal hyperplasia, which was accompanied by reductions in vascular cell proliferation and density. Furthermore, liraglutide treatment suppressed hyperglycemia-enhanced vascular inflammation 7 days after arterial injury. CONCLUSIONS: We demonstrate that endothelial cells are targets of liraglutide, and suppress restenosis via endothelial NO. Furthermore, the protective effects are maintained in severe hyperglycemia. Our findings provide an evidence base for a future clinical trial to determine whether treatment with GLP-1RAs represents potentially effective pharmacological therapy following angioplasty in patients with diabetes.

Combination Therapy with a Sodium-Glucose Cotransporter 2 Inhibitor and a Dipeptidyl Peptidase-4 Inhibitor Additively Suppresses Macrophage Foam Cell Formation and Atherosclerosis in Diabetic Mice.

Dipeptidyl peptidase-4 inhibitors (DPP-4is), in addition to their antihyperglycemic roles, have antiatherosclerotic effects. We reported that sodium-glucose cotransporter 2 inhibitors (SGLT2is) suppress atherosclerosis in a glucose-dependent manner in diabetic mice. Here, we investigated the effects of combination therapy with SGLT2i and DPP-4i on atherosclerosis in diabetic mice. SGLT2i (ipragliflozin, 1.0 mg/kg/day) and DPP-4i (alogliptin, 8.0 mg/kg/day), either alone or in combination, were administered to db/db mice or streptozotocin-induced diabetic apolipoprotein E-null (Apoe-/- ) mice. Ipragliflozin and alogliptin monotherapies improved glucose intolerance; however, combination therapy did not show further improvement. The foam cell formation of peritoneal macrophages was suppressed by both the ipragliflozin and alogliptin monotherapies and was further enhanced by combination therapy. Although foam cell formation was closely associated with HbA1c levels in all groups, DPP-4i alone or the combination group showed further suppression of foam cell formation compared with the control or SGLT2i group at corresponding HbA1c levels. Both ipragliflozin and alogliptin monotherapies decreased scavenger receptors and increased cholesterol efflux regulatory genes in peritoneal macrophages, and combination therapy showed additive changes. In diabetic Apoe-/- mice, combination therapy showed the greatest suppression of plaque volume in the aortic root. In conclusion, combination therapy with SGLT2i and DPP4i synergistically suppresses macrophage foam cell formation and atherosclerosis in diabetic mice.