A Clinical Case of Probable Sitosterolemia

Sitosterolemia is a rare genetic lipid disorder characterized by elevated plant sterols in the serum. A 24-year-old Japanese woman was referred to our hospital due to a high serum low-density lipoprotein cholesterol (LDL-C) level of 332 mg/dL. At first, she was suspected to suffer from familial hypercholesterolemia, and thus received lipid-lowering agents. Although her LDL-C level remained high (220 mg/dL) with diet therapy plus 10 mg/day rosuvastatin, it was drastically decreased to 46 mg/dL with the addition of 10 mg/day ezetimibe. Finally, her LDL-C level was well-controlled at about 70 mg/dL with 10 mg/day ezetimibe alone. Furthermore, while her serum sitosterol level was elevated at 10.5 μg/mL during the first visit to our hospital, it decreased to 3.6 μg/mL with the 10 mg/day ezetimibe treatment alone. These observations suggest that she might probably suffer from sitosterolemia. Therefore, targeted gene sequencing analysis was performed using custom panels focusing on the exome regions of 21 lipid-associated genes, including ABCG5, ABCG8, and familial hypercholesterolemia-causing genes (LDL receptor, LDLRAP1, PCSK9, and apolipoprotein B). We finally identified a heterozygous ABCG8 variant (NM_022437.2:c.1285A>G or NP_071882.1:p.Met429Val) in our patient. The same gene mutation was detected in her mother. We report here a rare case exhibiting probable sitosterolemia caused by a heterozygous Met429Val variant in the ABCG8 gene and additional unknown variants.

Subcutaneous Infusion of DNA-Aptamer Raised against Advanced Glycation End Products Prevents Loss of Skeletal Muscle Mass and Strength in Accelerated-Aging Mice

We have developed DNA aptamers that can inhibit the toxic effects of advanced glycation end products (AGE-Apts). We herein evaluated the effects of AGE-Apts on muscle mass and strength in senescence-accelerated mouse prone 8 (SAMP8) mice. Eight-month-old male SAMP8 mice received subcutaneous infusion of control DNA aptamers (CTR-Apts) or AGE-Apts. Mice in an age-matched senescence-accelerated mouse resistant strain 1 (SAMR1) group were treated with CTR-Apts as controls. The soleus muscles were collected after the 8-week intervention for weight measurement and histological, RT-PCR, and immunofluorescence analyses. Grip strength was measured before and after the 8-week intervention. AGE-Apt treatment inhibited the progressive decrease in the grip strength of SAMP8 mice. SAMP8 mice had lower soleus muscle weight and fiber size than SAMR1 mice, which was partly restored by AGE-Apt treatment. Furthermore, AGE-Apt-treated SAMP8 mice had a lower interstitial fibrosis area of the soleus muscle than CTR-Apt-treated SAMP8 mice. The soleus muscle levels of AGEs, oxidative stress, receptor for AGEs, and muscle ring-finger protein-1 were increased in the CTR-Apt-treated mice, all of which, except for AGEs, were inhibited by AGE-Apt treatment. Our present findings suggest that the subcutaneous delivery of AGE-Apts may be a novel therapeutic strategy for aging-related decrease in skeletal muscle mass and strength.

SMTP-44D Inhibits Atherosclerotic Plaque Formation in Apolipoprotein-E Null Mice Partly by Suppressing the AGEs-RAGE Axis

SMTP-44D has been reported to have anti-oxidative and anti-inflammatory reactions, including reduced expression of receptor for advanced glycation end products (RAGE) in experimental diabetic neuropathy. Although activation of RAGE with its ligands, and advanced glycation end products (AGEs), play a crucial role in atherosclerotic cardiovascular disease, a leading cause of death in diabetic patients, it remains unclear whether SMTP-44D could inhibit experimental atherosclerosis by suppressing the AGEs–RAGE axis. In this study, we investigated the effects of SMTP-44D on atherosclerotic plaque formation and expression of AGEs in apolipoprotein-E null (Apoe−/−) mice. We further studied here whether and how SMTP-44D inhibited foam cell formation of macrophages isolated from Apoe−/− mice ex vivo. Although administration of SMTP-44D to Apoe−/− mice did not affect clinical or biochemical parameters, it significantly decreased the surface area of atherosclerotic lesions and reduced the atheromatous plaque size, macrophage infiltration, and AGEs accumulation in the aortic roots. SMTP-44D bound to immobilized RAGE and subsequently attenuated the interaction of AGEs with RAGE in vitro. Furthermore, foam cell formation evaluated by Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and gene expression of RAGE, cyclin-dependent kinase 5 (Cdk5) and CD36 in macrophages isolated from SMTP-44D-treated Apoe−/− mice were significantly decreased compared with those from saline-treated mice. Gene expression levels of RAGE and Cdk5 were highly correlated with each other, the latter of which was also positively associated with that of CD36. The present study suggests that SMTP-44D may inhibit atherosclerotic plaque formation in Apoe−/− mice partly by blocking the AGEs-RAGE-induced ox-LDL uptake into macrophages via the suppression of Cdk5-CD36 pathway.

Triple combination therapy with telmisartan, amlodipine, and hydrochlorothiazide ameliorates albuminuria in a normotensive rat remnant kidney model

Background

Some types of antihypertensive drugs may have pleiotropic effects in patients with chronic kidney disease (CKD). However, whether triple combination therapy with angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), and thiazide diuretics (TZD) confer renoprotective effects in normotensive CKD remains unknown. Thus, we explored this issue using a normotensive rat remnant kidney model.

Methods

Sprague-Dawley rats were randomly allocated into four groups: sham (n = 10), 5/6 nephrectomy (NTx) (n = 9), NTx treated with telmisartan and amlodipine (dual) (n = 8), and NTx treated with telmisartan, amlodipine, and hydrochlorothiazide (triple) (n = 7), and followed for 4 weeks. Blood pressure (BP), blood chemistry including renal function, urinary albumin excretion (UAE), and renal pathology were evaluated in all groups.

Results

There was no significant change in systolic BP among the four groups during the study period. Serum blood urea nitrogen (BUN) was significantly higher, and 24-h creatinine clearance (Ccr) was lower in all NTx groups (p < 0.001). Dual therapy further increased the glomerular diameter in NTx rats (p < 0.001), which was significantly ameliorated by triple therapy (p < 0.001). Triple therapy, but not dual therapy, significantly reduced NTx-induced UAE levels (p < 0.05), whereas BUN, 24-h Ccr, and tubulointerstitial injury scores were comparable among all the NTx groups.

Conclusions

Our results suggest that triple combination therapy with telmisartan, amlodipine, and hydrochlorothiazide could ameliorate glomerular hypertrophy and albuminuria in normotensive CKD rats in a BP-lowering independent manner.

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-dependent insulinotropic polypeptide inhibits cardiac hypertrophy and fibrosis in diabetic mice via suppression of TGF-β2

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 β (β-Mhc) and transforming growth factor-beta2 (Tgf-β2) mRNA levels, all of which were inhibited by GIP infusion. High glucose increased NADPH oxidase-driven superoxide generation and up-regulated β-Mhc, Tgf-β2, and receptor for AGEs mRNA levels in cardiomyocytes, and augmented the AGE-induced β-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-β2.

DNA aptamer raised against receptor for advanced glycation end products suppresses renal tubular damage and improves insulin resistance in diabetic mice

OBJECTIVE

Interaction of advanced glycation end products (AGEs) with the receptor RAGE plays a role in diabetic nephropathy. However, effects of RAGE-aptamer on tubular damage remain unknown. We examined whether RAGE-aptamer inhibited tubular damage in KKAy/Ta mice, obese type 2 diabetic mice with insulin resistance.

MATERIALS AND METHODS

Male 8-week-old KKAy/Ta mice received continuous intraperitoneal infusion of either control-aptamer or RAGE-aptamer for 8 weeks. Blood biochemistry and blood pressure, and urinary N-acetyl-β-D-glucosaminidase (NAG) activity and albumin excretion levels were monitored. Kidney and adipose tissue samples were obtained for immunohistochemical analyses.

RESULTS

Although RAGE-aptamer did not affect blood glucose, blood pressure, body weight, or serum creatinine values, it significantly inhibited the increase in urinary NAG activity and HOMA-IR in diabetic mice at 12 and 16 and at 16 weeks old, respectively. Furthermore, compared with control-aptamer-treated mice, renal carboxymethyllysine, RAGE, and NADPH oxidase-driven superoxide generation were significantly decreased in RAGE-aptamer-treated mice at 12 weeks old with subsequent amelioration of histological alterations in glomerular and interstitial area, while adipose tissue adiponectin expression was increased.

CONCLUSION

Our present results suggest that RAGE-aptamer could inhibit tubular injury in obese type 2 diabetic mice partly by suppressing the AGE-RAGE-oxidative stress axis and improving insulin resistance.

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.

Butanolic Extract of Noni Inhibits Proliferation, Inflammation, and Proprotein Convertase Subtilisin Kexin Type 9 (PCSK9) Expression in Cultured Smooth Muscle Cells

Platelet-derived growth factor-BB (PDGF-BB) plays a central role in smooth muscle cell (SMC) proliferation and inflammation, being involved in atherosclerotic cardiovascular disease. We have previously found that butanolic extract of noni, a tropical plant belonging to the family Rubiaceae, exerts anti-inflammatory effects on endothelial cells exposed to advanced glycation end products (AGEs). Here, we examined the effects of noni extract on oxidative stress production, growth, and inflammatory reactions in PDGF-BB or AGE-exposed SMCs. Reactive oxygen species (ROS) generation, cell proliferation, and adhesion were measured by a fluorescent dye, a colorimetric agent, and labeled THP-1 cells, respectively. Gene and protein expression was evaluated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. Butanolic extract of noni reduced ROS production, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and proprotein convertase subtilisin kexin type 9 (PCSK9) expression, and proliferation in, and THP-1 cell adhesion to, PDGF-BB-exposed SMCs. Gene expression and protein level of receptor for AGEs (RAGE) were significantly decreased by noni extract in SMCs. Furthermore, AGEs significantly increased PCSK9 mRNA and protein levels in SMCs, which were inhibited by noni extract or an antioxidant N-acetylcysteine. Our present study suggests that butanolic extract of noni not only inhibits the PDGF-BB-induced proliferation and inflammatory reactions in SMCs through its antioxidative properties but also reduces PCSK9 levels in AGE-exposed SMCs via suppression of RAGE expression. Butanolic extract of noni may play a protective role against atherosclerosis.

Integral role of receptor for advanced glycation end products (RAGE) in nondiabetic atherosclerosis

An advanced glycation end products (AGE)/a receptor for AGE (RAGE) axis plays a central role in the pathogenesis of diabetic vascular remodeling. This study was conducted to clarify the role of RAGE in nondiabetic atherosclerosis. We used the aortic and coronary atherosclerotic lesions of Watanabe heritable hyperlipidemic (WHHL) rabbits prone to myocardial infarction (WHHLMI) at 1 to 14 months. Immunohistochemistry demonstrated the significant expression of RAGE as early as at 1 month with the stronger expression at 3 and 7 months, which was remarkably diminished at 14 months. RAGE expression was concordant with AGE accumulation. The major original sources of RAGE expression were macrophages and smooth muscle cells in addition to endothelial cells, and RAGE expression was distributed in the areas of phospholipid products, a component of oxidized LDL and nitrotyrosine. The concentrations of serum AGE did not alter significantly with aging. These findings suggested the expression of RAGE was induced by hyperlipidemia and oxidative stress independent of diabetes in WHHLMI rabbits. Additionally, our in vitro study showed that silencing of RAGE tended to attenuate oxidized-LDL-triggered PAI-1 expression in human cultured macrophages, as well as oxidized-LDL-induced tissue factor expression in peritoneal macrophages, suggesting a possible role of RAGE in prothrombogenic molecular regulation. In conclusion, the present study provides in vivo evidence that RAGE plays an integral role in the initiation and progression of nondiabetic atherosclerosis, suggesting that RAGE may be a novel target for treating not only diabetic but also nondiabetic vascular complications.

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-1β 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-1β 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.

Glyceraldehyde-Derived Pyridinium Evokes Renal Tubular Cell Damage via RAGE Interaction

Glyceraldehyde-derived advanced glycation end products (glycer-AGEs) contribute to proximal tubulopathy in diabetes. However, what glycer-AGE structure could evoke tubular cell damage remains unknown. We first examined if deleterious effects of glycer-AGEs on reactive oxygen species (ROS) generation in proximal tubular cells were blocked by DNA-aptamer that could bind to glyceraldehyde-derived pyridinium (GLAP) (GLAP-aptamer), and then investigated whether and how GLAP caused proximal tubular cell injury. GLAP-aptamer and AGE-aptamer raised against glycer-AGEs were prepared using a systemic evolution of ligands by exponential enrichment. The binding affinity of GLAP-aptamer to glycer-AGEs was measured with a bio-layer interferometry. ROS generation was evaluated using fluorescent probes. Gene expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). GLAP-aptamer bound to glycer-AGEs with a dissociation constant of 7.7 × 10⁻⁵ M. GLAP-aptamer, glycer-AGE-aptamer, or antibodies directed against receptor for glycer-AGEs (RAGE) completely prevented glycer-AGE- or GLAP-induced increase in ROS generation, MCP-1, PAI-1, or RAGE gene expression in tubular cells. Our present results suggest that GLAP is one of the structurally distinct glycer-AGEs, which may mediate oxidative stress and inflammatory reactions in glycer-AGE-exposed tubular cells. Blockade of the interaction of GLAP-RAGE by GLAP-aptamer may be a therapeutic target for proximal tubulopathy in diabetic nephropathy.

N-butanol extracts of Morinda citrifolia suppress advanced glycation end products (AGE)-induced inflammatory reactions in endothelial cells through its anti-oxidative properties

Background

Advanced glycation end products (AGEs), senescent macroprotein derivatives formed during a normal aging process and acceleratedly under diabetic conditions, play a role in atherosclerotic cardiovascular disease. AGEs cause endothelial cell (EC) damage, an initial trigger for atherosclerosis through the interaction with a receptor for AGEs (RAGE). We have previously shown that n-butanol extracts of Morinda citrifolia (noni), a plant belonging to the family Rubiaceae, block the binding of AGEs to RAGE in vitro. In this study, we examined the effects of n-butanol extracts of noni on reactive oxygen species (ROS) generation and inflammatory reactions on AGE-exposed human umbilical vein ECs (HUVECs).

Methods

HUVECs were treated with 100 μg/ml AGE-bovine serum albumin (AGE-BSA) or non-glycated BSA in the presence or absence of 670 ng/ml n-butanol extracts of noni for 4 h. Then ROS generation and inflammatory and gene expression in HUVECs were evaluated by dihydroethidium staining and real-time reverse transcription-polymerase chain reaction analyses, respectively. THP-1 cell adhesion to HUVECs was measured after 2-day incubation of AGE-BSA or BSA in the presence or absence of 670 ng/ml n-butanol extracts of noni.

Results

N-butanol extracts of noni at 670 ng/ml significantly inhibited the AGE-induced ROS generation and RAGE, intercellular adhesion molecule-1 and plasminogen activator inhibitor-1 gene expressions in HUVECs. AGEs significantly increased monocytic THP-1 cell adhesion to HUVECs, which was also prevented by 670 ng/ml n-butanol extracts of noni.

Conclusions

The present study demonstrated for the first time that N-butanol extracts of noni could suppress the AGE-induced inflammatory reactions in HUVECs through its anti-oxidative properties via blocking of the interaction of AGEs with RAGE. Inhibition of the AGE-RAGE axis by n-butanol extracts of noni may be a novel nutraceutical strategy for the treatment of cardiovascular disease.

Insulin resistance is an independent correlate of high serum levels of advanced glycation end products (AGEs) and low testosterone in non-diabetic men

Advanced glycation end products (AGEs) are involved in cardiovascular disease. Low testosterone level is associated with increased risks of cardiometabolic disorders as well. However, which anthropometric and metabolic variables, including AGEs, are independently correlated with low testosterone is largely unknown. In this study, we investigated whether high serum level of AGEs is one of the independent determinants of low testosterone in non-diabetic men. One hundred thirteen non-diabetic men who did not receive any drugs for hypertension and dyslipidemia underwent a complete history and physical examination, determination of blood chemistries, including serum AGEs and testosterone. Univariate analysis showed that testosterone levels were associated with waist circumference (inversely), diastolic blood pressure (BP) (inversely), mean BP (inversely), triglycerides (inversely), HDL-cholesterol, fasting plasma glucose (inversely), fasting insulin (inversely), homeostasis model assessment of insulin resistance (HOMA-IR) (inversely), AGEs (inversely) and uric acid (inversely). By the use of multiple stepwise regression analyses, HOMA-IR (p = 0.005) and triglycerides levels (p < 0.05) remained significant and were independently related to testosterone levels (R² = 0.168). HOMA-IR index was one of the independent determinants of serum levels of AGEs as well. The present study demonstrated for the first time that HOMA-IR was independently associated with high serum levels of AGEs and low testosterone in non-diabetic men. Insulin resistance could link elevation of AGEs to testosterone deficiency in non-diabetic men.

Vascular Inflammation Evaluated by [ 18 F]-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography Is Associated With Endothelial Dysfunction

Objective—

Endothelial dysfunction is an initial step in atherosclerotic cardiovascular disease. However, involvement of vascular inflammation in endothelial dysfunction is not fully investigated in humans because of the lack of diagnostic modality to noninvasively evaluate vascular inflammation. We assessed the relationship between endothelial function and vascular inflammation evaluated by [ 18 F]-fluorodeoxyglucose-positron emission tomography/computed tomographic imaging.

Approach and Results—

We examined endothelial function and vascular inflammation by flow-mediated dilation (FMD) of the brachial artery and [ 18 F]-fluorodeoxyglucose-positron emission tomography/computed tomographic imaging of carotid arteries, respectively, in 145 subjects (95 men and 50 women; mean age, 61.8±9.5 years) who underwent a risk-screening test for cardiovascular disease in Kurume University Hospital. Vascular inflammation was measured by blood-normalized standardized uptake value, known as a target:background ratio (TBR). We investigated whether absolute changes from baseline of %FMD after antihypertensive treatment for 6 months (Δ%FMD) were correlated with those of TBR in 33 drug-naive patients with essential hypertension. Multiple logistic regression analysis revealed that age (odds ratio, 1.767 for 10-year increase), male sex (odds ratio, 0.434), low-density lipoprotein-cholesterol (odds ratio, 1.630 for 26-mg/dL increase), and TBR values (odds ratio, 1.759 for 0.2 increase) were independently associated with %FMD in 145 patients. There was an inverse correlation between Δ%FMD and ΔTBR; ΔTBR was a sole independent associate of Δ%FMD in hypertensive patients ( r =−0.558; P <0.001).

Conclusions—

The present study showed that vascular inflammation in the carotid arteries evaluated by [ 18 F]-fluorodeoxyglucose-positron emission tomography/computed tomography was one of the independent correlates of decreased %FMD, thus suggesting the association of vascular inflammation with endothelial dysfunction in humans.

Dipeptidyl peptidase-4 deficiency protects against experimental diabetic nephropathy partly by blocking the advanced glycation end products-receptor axis

Advanced glycation end products (AGEs) and their receptor (RAGE) have a role in diabetic nephropathy. We have recently found that linagliptin, an inhibitor of dipeptidyl peptidase-4 (DPP-4), could inhibit renal damage in type 1 diabetic rats by suppressing the AGE-RAGE axis. However, it remains unclear whether DPP-4 deficiency could also have beneficial effects on experimental diabetic nephropathy. To address the issue, we rendered wild-type F344/NSlc and DPP-4-deficient F344/DuCrl/Crlj rats diabetic by injection of streptozotocin, and then investigated whether DPP-4 deficiency could block the activation of AGE-RAGE axis in the diabetic kidneys and resultantly ameliorate renal injury in streptozotocin-induced diabetic rats. Compared with control rats at 9 and 11 weeks old, body weight and heart rates were significantly lower, while fasting blood glucose was higher in wild-type and DPP-4-deficient diabetic rats at the same age. There was no significant difference of body weight, fasting blood glucose and lipid parameters between the two diabetic rat strains. AGEs, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nitrotyrosine levels in the kidney, renal gene expression of RAGE and intercellular adhesion molecule-1, glomerular area, urinary excretion of 8-OHdG and albumin, and the ratio of renal to body weight were increased in wild-type diabetic rats at 9 and/or 11 weeks old compared with age-matched control rats, all of which except for urinary 8-OHdG levels at 11 weeks old were significantly suppressed in DPP-4-deficient diabetic rats. Our present study suggests that DPP-4 deficiency could exert beneficial actions on type 1 diabetic nephropathy partly by blocking the AGE-RAGE axis. DPP-4 might be a novel therapeutic target for preventing diabetic nephropathy.

Altered serum glyceraldehyde-derived advanced glycation end product (AGE) and soluble AGE receptor levels indicate carbonyl stress in patients with schizophrenia

Recent cross-sectional and longitudinal studies indicate that measurements of peripheral blood carbonyl stress markers such as the advanced glycation end product (AGE) pentosidine and the reactive carbonyl-detoxifying B6 vitamin pyridoxal could be used as therapeutic biological markers in subpopulations of schizophrenia patients. Glyceraldehyde-derived AGEs (Glycer-AGE) have strong neurotoxicity, and soluble receptors for AGEs (sRAGE) may ameliorate the effects of AGEs. In the present study, we measured Glycer-AGEs and sRAGE levels to determine their potential as diagnostic, therapeutic, or clinical biological markers in patients with schizophrenia. After enrollment of 61 admitted Japanese patients with acute schizophrenia and 39 healthy volunteers, 54 patients were followed up from the acute stage to remission. Serum biomarkers were measured in blood samples taken before breakfast using competitive enzyme-linked immunosorbent assays, and Glycer-AGEs were significantly higher and sRAGE levels were significantly lower in patients with acute schizophrenia than in healthy controls. Glycer-AGEs/sRAGE ratios were also higher in schizophrenia patients and were stable during the clinical course. Furthermore, discriminant analyses confirmed that Glycer-AGEs and Glycer-AGEs/sRAGE ratios are significant diagnostic markers for schizophrenia, and distinguished between patients and healthy controls in 70.0% of cases. However, these markers of carbonyl stress were not correlated with clinical features, including disease severity, or with daily chlorpromazine doses. These data indicate the potential of Glycer-AGEs, RAGEs, and their relative ratios as diagnostic markers for patients with schizophrenia.

Assessment of the concentrations of various advanced glycation end-products in beverages and foods that are commonly consumed in Japan

Dietary consumption has recently been identified as a major environmental source of pro-inflammatory advanced glycation end-products (AGEs) in humans. It is disputed whether dietary AGEs represent a risk to human health. N^ε-(carboxymethyl)lysine (CML), a representative AGE compound found in food, has been suggested to make a significant contribution to circulating CML levels. However, recent studies have found that the dietary intake of AGEs is not associated with plasma CML concentrations. We have shown that the serum levels of glyceraldehyde-derived AGEs (Glycer-AGEs), but not hemoglobin A1c, glucose-derived AGEs (Glu-AGEs), or CML, could be used as biomarkers for predicting the progression of atherosclerosis and future cardiovascular events. We also detected the production/accumulation of Glycer-AGEs in normal rats administered Glu-AGE-rich beverages. Therefore, we assessed the concentrations of various AGEs in a total of 1,650 beverages and foods that are commonly consumed in Japan. The concentrations of four kinds of AGEs (Glu-AGEs, fructose-derived AGEs (Fru-AGEs), CML, and Glycer-AGEs) were measured with competitive enzyme-linked immunosorbent assays involving immunoaffinity-purified specific antibodies. The results of the latter assays indicated that Glu-AGEs and Fru-AGEs (especially Glu-AGEs), but not CML or Glycer-AGEs, are present at appreciable levels in beverages and foods that are commonly consumed by Japanese. Glu-AGEs, Fru-AGEs, CML, and Glycer-AGEs exhibited concentrations of ≥85%, 2–12%, <3%, and trace amounts in the examined beverages and ≥82%, 5–15%, <3%, and trace amounts in the tested foods, respectively. The results of the present study indicate that some lactic acid bacteria beverages, carbonated drinks, sugar-sweetened fruit drinks, sports drinks, mixed fruit juices, confectionery (snacks), dried fruits, cakes, cereals, and prepared foods contain markedly higher Glu-AGE levels than other classes of beverages and foods. We provide useful data on the concentrations of various AGEs, especially Glu-AGEs, in commonly consumed beverages and foods.

[Diabetic macrovascular complications]

Reactive derivatives from non-enzymatic glucose-protein condensation reactions, as well as lipids and nucleic acids exposed to reducing sugars, form a heterogeneous group of irreversible adducts called "advanced glycation end products(AGEs)". The formation and accumulation of AGEs have been known to progress at an accelerated rate under diabetes. There is accumulating evidence that AGEs and their receptor (RAGE) interaction elicits oxidative stress generation and subsequently evokes inflammatory and thrombogenic reactions, thereby being involved in vascular complications in diabetes. We, along with others, have recently found that pigment epithelium-derived factor(PEDF), a glycoprotein that belongs to the superfamily of serine protease inhibitors, has neuroprotective, anti-angiogenic, anti-oxidative, and anti-inflammatory properties both in cell culture and animal models. In this review, we discuss the role of AGE-RAGE axis in diabetic macroangiopathy and its therapeutic intervention by PEDF.

Role of receptor for advanced glycation end products (RAGE) in liver disease

Receptor for advanced glycation end products (RAGE) belongs to a immunoglobulin superfamily of cell surface molecules that could bind to a number of ligands such as advanced glycation end products, high-mobility group protein box-1, S-100 calcium-binding protein, and amyloid-β-protein, inducing a series of signal transduction cascades, and being involved in a variety of cellular function, including inflammation, proliferation, apoptosis, angiogenesis, migration, and fibrosis. RAGE is expressed in hepatic stellate cells and hepatocytes and hepatoma cells. There is accumulating evidence that engagement of RAGE with various ligands elicits oxidative stress generation and subsequently activates the RAGE downstream pathway in the liver, thereby contributing to the development and progression of numerous types of hepatic disorders. These observations suggest that inhibition of the RAGE signaling pathway could be a novel therapeutic target for liver diseases. This article summarizes the pathological role of RAGE in hepatic insulin resistance, steatosis and fibrosis, ischemic and non-ischemic liver injury, and hepatocellular carcinoma growth and metastasis and its therapeutic interventions for these devastating disorders.

Crosstalk between advanced glycation end products (AGEs)-receptor RAGE axis and dipeptidyl peptidase-4-incretin system in diabetic vascular complications

Advanced glycation end products (AGEs) consist of heterogenous group of macroprotein derivatives, which are formed by non-enzymatic reaction between reducing sugars and amino groups of proteins, lipids and nucleic acids, and whose process has progressed at an accelerated rate under diabetes. Non-enzymatic glycation and cross-linking of protein alter its structural integrity and function, contributing to the aging of macromolecules. Furthermore, engagement of receptor for AGEs (RAGE) with AGEs elicits oxidative stress generation and subsequently evokes proliferative, inflammatory, and fibrotic reactions in a variety of cells. Indeed, accumulating evidence has suggested the active involvement of accumulation of AGEs in diabetes-associated disorders such as diabetic microangiopathy, atherosclerotic cardiovascular diseases, Alzheimer’s disease and osteoporosis. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretins, gut hormones secreted from the intestine in response to food intake, both of which augment glucose-induced insulin release, suppress glucagon secretion, and slow gastric emptying. Since GLP-1 and GIP are rapidly degraded and inactivated by dipeptidyl peptidase-4 (DPP-4), inhibition of DPP-4 and/or DPP-4-resistant GLP-1 analogues have been proposed as a potential target for the treatment of diabetes. Recently, DPP-4 has been shown to cleave multiple peptides, and blockade of DPP-4 could exert diverse biological actions in GLP-1- or GIP-independent manner. This article summarizes the crosstalk between AGEs-RAGE axis and DPP-4-incretin system in the development and progression of diabetes-associated disorders and its therapeutic intervention, especially focusing on diabetic vascular complications.

Glyceraldehyde-derived pyridinium (GLAP) evokes oxidative stress and inflammatory and thrombogenic reactions in endothelial cells via the interaction with RAGE

Background

We have previously shown that serum levels of glyceraldehyde-derived advanced glycation end products (Gly-AGEs) are elevated under oxidative stress and/or diabetic conditions and associated with insulin resistance, endothelial dysfunction and vascular inflammation in humans. Further, Gly-AGEs not only evoke oxidative and inflammatory reactions in endothelial cells (ECs) through the interaction with a receptor for AGEs (RAGE), but also mimic vasopermeability effects of AGE-rich serum purified from diabetic patients on hemodialysis. These observations suggest that Gly-AGE-RAGE system might be a therapeutic target for vascular complications in diabetes. However, since incubation of glyceraldehyde with proteins will generate a large number of structurally distinct AGEs, it remains unclear what type of AGE structures could mediate the deleterious effects of Gly-AGEs on ECs.

Aims and Methods

Therefore, in this study, we examined (1) whether glyceraldehyde-derived pyridinium (GLAP), one of the Gly-AGEs generated by the incubation of lysine with glyceraldehyde, elicited reactive oxygen species (ROS) generation and inflammatory and thrombogenic gene expression in human umbilical vein ECs (HUVECs) via the interaction with RAGE and (2) if DNA aptamers raised against Gly-AGEs or GLAP (AGE-aptamer or GLAP-aptamer) inhibited the binding of GLAP to RAGE and subsequently suppressed the harmful effects of GLAP on HUVECs.

Results

GLAP stimulated ROS generation in a bell-shaped manner; GLAP at 10 μg/ml increased ROS generation in HUVECs by 40%, which was blocked by the treatment with RAGE-antibody (RAGE-Ab). Ten μg/ml GLAP significantly up-regulated mRNA levels of RAGE, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and plasminogen activator inhibitor-1 in HUVECs, which were also suppressed by RAGE-Ab. AGE-aptamer or GLAP-aptamer significantly blocked these deleterious effects of GLAP on HUVECs. Moreover, quartz crystal microbalance analyses revealed that GLAP actually bound to RAGE and that AGE-aptamer or GLAP-aptamer inhibited the binding of GLAP to RAGE.

Conclusions

The present study suggests that GLAP might be a main glyceraldehyde-related AGE structure in Gly-AGEs that bound to RAGE and subsequently elicited ROS generation and inflammatory and thrombogenic reactions in HUVECs. Blockade of the GLAP-RAGE interaction by AGE-aptamer or GLAP-aptamer might be a novel therapeutic strategy for preventing vascular injury in diabetes.

Insulin stimulates SGLT2-mediated tubular glucose absorption via oxidative stress generation

BACKGROUND

Ninety percent of glucose filtered by the glomerulus is reabsorbed by a sodium-glucose cotransporter 2 (SGLT2), which is expressed mainly on the apical membrane of renal proximal tubules. Since SGLT-2-mediated glucose reabsorption is enhanced under diabetic conditions, selective inhibition of SGLT2 has been proposed as a potential therapeutic target for the treatment of patients with diabetes. However, it remains unclear which diabetes-associated factors are involved in overexpression of SGLT2.

METHODS

Therefore, in this study, we examined whether insulin, high glucose, advanced glycation end products (AGEs), or H2O2 stimulated SGLT2 expression in human cultured proximal tubular cells, and then investigated the underlying molecular mechanisms.

RESULTS

High glucose or AGEs did not affect SGLT2 expression in tubular cells. Insulin significantly increased tubular SGLT2 level in a dose-dependent manner, whereas bell-shaped dose-response curves were observed for H2O2-treated cells. An anti-oxidant, N-acetylcysteine completely blocked insulin-induced up-regulation of SGLT2 as well as increase in glucose absorption by tubular cells. Furthermore, insulin dose-dependently increased reactive oxygen species generation in tubular cells.

CONCLUSIONS

Our present study demonstrated that insulin could stimulate SGLT-2-mediated glucose entry into cultured proximal tubular cells via oxidative stress generation. Suppression of the insulin-induced overexpression of SGLT2 in tubular cells might be a novel therapeutic strategy for the treatment of diabetic nephropathy.

Involvement of the TAGE-RAGE system in non-alcoholic steatohepatitis: Novel treatment strategies

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver disease around the world. It includes a spectrum of conditions from simple steatosis to non-alcoholic steatohepatitis (NASH) and can lead to fibrosis, cirrhosis, liver failure, and/or hepatocellular carcinoma. NAFLD is also associated with other medical conditions such as obesity, diabetes mellitus (DM), metabolic syndrome, hypertension, insulin resistance, hyperlipidemia, and cardiovascular disease (CVD). In diabetes, chronic hyperglycemia contributes to the development of both macro- and microvascular conditions through a variety of metabolic pathways. Thus, it can cause a variety of metabolic and hemodynamic conditions, including upregulated advanced glycation end-products (AGEs) synthesis. In our previous study, the most abundant type of toxic AGEs (TAGE); i.e., glyceraldehyde-derived AGEs, were found to make a significant contribution to the pathogenesis of DM-induced angiopathy. Furthermore, accumulating evidence suggests that the binding of TAGE with their receptor (RAGE) induces oxidative damage, promotes inflammation, and causes changes in intracellular signaling and the expression levels of certain genes in various cell populations including hepatocytes and hepatic stellate cells. All of these effects could facilitate the pathogenesis of hypertension, cancer, diabetic vascular complications, CVD, dementia, and NASH. Thus, inhibiting TAGE synthesis, preventing TAGE from binding to RAGE, and downregulating RAGE expression and/or the expression of associated effector molecules all have potential as therapeutic strategies against NASH. Here, we examine the contributions of RAGE and TAGE to various conditions and novel treatments that target them in order to prevent the development and/or progression of NASH.

Carnitine deficiency is associated with late-onset hypogonadism and depression in uremic men with hemodialysis

Late-onset hypogonadism (LOH) and depression contribute to cardiovascular disease (CVD) in male hemodialysis (HD) patients. Carnitine deficiency is frequently observed in HD patients, playing a role in CVD. We examined whether carnitine deficiency was independently associated with LOH and depression in these patients. Twenty-six male HD patients underwent determinations of serum levels of free carnitine and testosterone. Status of LOH and depression were evaluated by questionnaires using aging male symptoms' (AMS) scale and self-rating depression scale (SDS), respectively. Free carnitine and testosterone levels in male HD patients were significantly lower than those in age-matched healthy male subjects. Linear regression analysis showed that AMS scale was positively associated with SDS. Univariate regression analysis revealed that total carnitine (inversely), free carnitine (inversely) and HD duration were correlated with AMS scale. Multiple stepwise regression analysis revealed that free carnitine was an independent determinant of AMS scale. Furthermore, free carnitine was also independently correlated with SDS in male HD patients. This study demonstrated that decreased free carnitine levels were independently associated with AMS scale and SDS in male HD patients. The observations suggest that decreased free carnitine levels could be a marker and therapeutic target of LOH and depression in uremic men with HD.

Switching to multiple daily injection therapy with glulisine improves glycaemic control, vascular damage and treatment satisfaction in basal insulin glargine-injected diabetic patients

BACKGROUND

Basal and bolus insulin therapy is required for strict blood control in diabetic patients, which could lead to prevention of vascular complications in diabetes. However, the optimal combination regimen is not well established.

METHODS

Fifty-nine diabetic patients (49 type 1 and 10 type 2; 52.9 ± 13.3 years old) whose blood glucose levels were uncontrolled (HbA1c  > 6.2%) by combination treatment of basal insulin glargine with multiple daily pre-meal injections of bolus short-acting insulin [aspart (n = 19), lispro (n = 37) and regular human insulin (n = 3)] for at least 8 weeks were enrolled in this study. We examined whether glycaemic control and vascular injury were improved by replacement of short-acting insulin with glulisine. Patient satisfaction was assessed with Diabetes Treatment Satisfaction Questionnaire.

RESULTS

Although bolus and basal insulin doses were almost unchanged before and after replacement therapy, switching to glulisine insulin for 24 weeks significantly decreased level of HbA1c , advanced glycation end products (AGEs), soluble receptor for AGEs (sRAGE), monocyte chemoattractant protein-1 (MCP-1) and urinary albumin excretion. In multiple stepwise regression analysis, change in MCP-1 values from baseline (ΔMCP-1) was a sole determinant of log urinary albumin excretion. ΔAGEs and ΔsRAGE were independently correlated with each other. The relationship between ΔMCP-1 and ΔsRAGE was marginally significant (p = 0.05). Replacement of short-acting insulin by glulisine significantly increased Diabetes Treatment Satisfaction Questionnaire scores.

CONCLUSIONS

Our present study suggests that combination therapy of glargine with multiple daily pre-meal injections of glulisine might show superior efficacy in controlling blood glucose, preventing vascular damage and improving treatment satisfaction in diabetic patients.

Elevation of Serum Levels of Advanced Glycation End Products in Patients With Non-B or Non-C Hepatocellular Carcinoma

BACKGROUND

The prevalence of non-B or non-C hepatocellular carcinoma (NBNC-HCC) has been increasing all over the world. Advanced glycation end products (AGE) play a role in the pathogenesis of alcoholic liver injury or nonalcoholic steatohepatitis (NASH).

METHODS

We examined here whether serum levels of AGE were elevated in NBNC-HCC patients compared with NASH subjects without HCC and investigated which anthropometric and clinical variables were independent determinants of AGE.

RESULTS

Ninety NBNC-HCC, 56 NASH, and 27 control subjects underwent a complete history and physical examination, determination of blood chemistries, including AGE levels. Serum levels of AGE were significantly higher in NBNC-HCC patients compared with NASH and control subjects [9.1 ± 2.7, 5.2 ± 1.7, 3.5 ± 1.2 (U/ml), respectively, P < 0.05]. Univariate analysis showed that AGE levels were associated with male (P < 0.05), age (P < 0.01), aspartate aminotransferase (P < 0.05), γ-glutamyl transpeptidase (GGT) (P < 0.01), HDL-cholesterol (inversely, P < 0.01), fasting plasma glucose (P < 0.01), and HbA1c (P < 0.05). By the use of multiple stepwise regression analysis, age, GGT, and HDL-cholesterol (inversely) remained significant and were independently related to AGE levels (R(2) = 0.406).

CONCLUSION

The present results suggest that AGE might be involved in the pathogenesis of NBNC-HCC, thereby being a biomarker that could discriminate NBNC-HCC from NASH.

Elevation of soluble form of receptor for advanced glycation end products (sRAGE) in recurrent pregnancy losses (RPL): possible participation of RAGE in RPL

OBJECTIVE

To determine whether the soluble receptor for advanced glycation end products (sRAGE) and immune inflammatory markers are associated with recurrent pregnancy losses (RPL).

DESIGN

Prospective case-control study.

SETTING

University clinic.

PATIENT(S)

A total of 93 women (age 35.8±4.6 years) were enrolled including 63 women with three or more recurrent pregnancy losses (RPL), and age-matched fertile controls with a history of at least one live birth and no history of pregnancy losses (n=30).

INTERVENTION(S)

Peripheral blood collection.

MAIN OUTCOME MEASURE(S)

Assessment of anthropometric, metabolic, and inflammatory immune variables.

RESULT(S)

Levels of sRAGE were statistically significantly higher in RPL patients than in control patients (1,528.9±704.5 vs. 1,149.9±447.4 pg/mL). In the multivariate analysis, the levels of insulin, plasminogen activator inhibitor-1, the resistance index of the uterine radial artery, and the ratio of tumor necrosis factor-α/interleukin-10 producing T helper cells were statistically significantly associated with the serum sRAGE level.

CONCLUSION(S)

Elevated levels of serum sRAGE are associated with RPL. The soluble receptor for advanced glycation end products might contribute to RPL by reducing uterine blood flow and subsequently causing ischemia in the fetus via inflammatory and thrombotic reactions.

Pioglitazone decreases asymmetric dimethylarginine levels in patients with impaired glucose tolerance or type 2 diabetes

BACKGROUND AND AIMS

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is a biomarker and mediator of cardiovascular disease in patients with impaired glucose tolerance (IGT) or diabetes mellitus (DM). Advanced glycation end products (AGEs) and their receptor (RAGE) axis is involved in ADMA generation as well. However, it remains unclear whether pioglitazone could decrease ADMA levels by reducing RAGE expression in humans.

DESIGN AND METHODS

Forty-eight IGT or type 2 DM (T2DM) patients were assigned to receive either pioglitazone (n=29) or glimepiride (n=19) and evaluated at baseline and 16 weeks of follow-up. We compared the effects of pioglitazone and glimepride on ADMA and soluble form of RAGE (sRAGE) levels and then studied whether the changes in serum ADMA level (ΔADMA) after treatment with pioglitazone were correlated with ΔsRAGE. We further examined which Δclinical variables were independently associated with ΔADMA.

RESULTS

After 16-week treatments, fasting plasma glucose and glycated hemoglobin (HbA1c) values were comparably reduced in both groups. Compared with glimepiride, pioglitazone treatment significantly decreased ADMA levels and improved insulin sensitivity, while it elevated high-density lipoprotein cholesterol (HDL-C) and sRAGE values and increased body weight and waist circumference. In multiple stepwise regression analysis, log-transformed Δfibronectin were a sole independent determinant of log-transformed ΔADMA (r=-0.551, R²=0.303).

CONCLUSIONS

This study demonstrated that pioglitazone decreased serum ADMA levels in a glucose-lowering independent manner. Elevation of fibronectin by pioglitazone may contribute to the reduction of serum levels of ADMA in IGT or T2DM subjects, thus playing a protective role against cardiovascular disease.

Pioglitazone decreases coronary artery inflammation in impaired glucose tolerance and diabetes mellitus: evaluation by FDG-PET/CT imaging

OBJECTIVES

The aim of this study was to compare the effect of pioglitazone with glimepiride on coronary arterial inflammation with serial (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) combined with computed tomography (CT) angiography.

BACKGROUND

Recent studies have shown that FDG-PET combined with CT is a reliable tool to visualize and quantify vascular inflammation. Although pioglitazone significantly prevented the progression of coronary atherosclerosis and reduced the recurrence of myocardial infarction in patients with type 2 diabetes mellitus (DM), it remains unclear whether pioglitazone could attenuate coronary artery inflammation.

METHODS

Fifty atherosclerotic patients with impaired glucose tolerance or type 2 DM underwent determination of blood chemistries, anthropometric and inflammatory variables, and FDG-PET/CT angiography, and then were randomized to receive either pioglitazone or glimepiride for 16 weeks. Effects of the treatments on vascular inflammation of the left main trunk were evaluated by FDG-PET/CT angiography at baseline and end of the study. Vascular inflammation of the left main trunk was measured by blood-normalized standardized uptake value, known as a target-to-background ratio.

RESULTS

Three patients dropped out of the study during the assessment or treatment. Finally, 25 pioglitazone-treated patients and 22 glimepiride-treated patients (37 men; mean age: 68.1 ± 8.3 years; glycosylated hemoglobin: 6.72 ± 0.70%) completed the study. After 16-week treatments, fasting plasma glucose and glycosylated hemoglobin values were comparably reduced in both groups. Changes in target-to-background ratio values from baseline were significantly greater in the pioglitazone group than in the glimepiride group (-0.12 ± 0.06 vs. 0.09 ± 0.07, p = 0.032), as well as changes in high-sensitivity C-reactive protein (pioglitazone vs. glimepiride group: median: -0.24 [interquartile range (IQR): -1.58 to -0.04] mg/l vs. 0.08 [IQR: -0.07 to 0.79] mg/l, p = 0.031).

CONCLUSIONS

Our study indicated that pioglitazone attenuated left main trunk inflammation in patients with impaired glucose tolerance or DM in a glucose-lowering independent manner, suggesting that pioglitazone may protect against cardiac events in patients with impaired glucose tolerance or DM by suppressing coronary inflammation. (Anti-Inflammatory Effects of Pioglitazone; NCT00722631).