Rika Naruse

Serum level of soluble CD26/dipeptidyl peptidase-4 (DPP-4) predicts the response to sitagliptin, a DPP-4 inhibitor, in patients with type 2 diabetes controlled inadequately by metformin and/or sulfonylurea

Dipeptidyl peptidase 4 (DPP-4) inhibitors is a new class of antihyperglycemic agents that is now available for the treatment of type 2 diabetes. We investigated the relationship between the baseline serum level of soluble CD 26/DPP-4 and the response to treatment with sitagliptin, a DPP-4 inhibitor, over 24 weeks in patients who had type 2 diabetes inadequately controlled by metformin and/or sulfonylurea therapy. We studied 52 consecutive patients with type 2 diabetes who had poor glycemic control despite treatment with metformin and/or sulfonylurea. All patients were given 50 mg/day of sitagliptin and were followed at monthly intervals for 24 weeks. Treatment with sitagliptin decreased significantly hemoglobin A1c (HbA1c) from 7.91 ± 1.08% at baseline to 6.96 ± 1.18% at 8 weeks, 7.04 ± 0.77% at 16 weeks, and 7.08 ± 0.80% at 24 weeks. The baseline serum level of sCD26 was correlated positively with HbA1c at both 16 weeks and 24 weeks. Furthermore, the serum sCD26 level at baseline was also correlated positively with the changes from baseline of HbA1c at 16 and 24 weeks (r = 0.318, P = 0.0296 and r = 0.516, P = 0.0003, respectively). In a multivariate logistic regression model that explained 56.1% (R(2) = 0.561) of the variation of the changes from baseline of HbA1c at 24 weeks, the baseline HbA1c (β = -0.638, P < 0.001) and serum sCD26 (β = 0.357, P = 0.041) were independent determinants of the change of HbA1c at 24 weeks. In conclusions, a higher serum level of sCD26 is associated with a worse response to sitagliptin in patients with type 2 diabetes controlled inadequately by metformin and/or sulfonylurea therapy.

Relation between serum high molecular weight adiponectin and serum ferritin or prohepcidin in patients with type 2 diabetes

An increase of serum ferritin, an indicator of body iron store, is associated with insulin resistance and with an increased risk of type 2 diabetes in the general population. A low serum adiponectin is also associated with insulin resistance. Recently, hepcidin was identified as a regulator of iron metabolism. We investigated whether serum adiponectin was associated with serum ferritin or prohepcidin, a precursor of hepcidin, in healthy subjects and patients with type 2 diabetes. We studied 65 healthy subjects and 104 patients with type 2 diabetes. A serum ferritin concentration ≥ 300 ng/ml for men or ≥ 150 ng/ml for women was defined as hyperferritinemia. Serum ferritin was significantly higher and serum prohepcidin was significantly lower in diabetic patients than in control subjects. Serum total and high molecular weight (HMW) adiponectin correlated negatively with serum ferritin in control subjects or diabetic patients, while serum total and HMW adiponectin correlated positively with serum prohepcidin in diabetic patients, but not in control subjects. Serum total and HMW adiponectin were lower in patients with hyperferritinemia than in those without it. In conclusion, serum ferritin was increased in type 2 diabetic patients, while serum prohepcidin was decreased. A high serum ferritin was associated with insulin resistance, and with low serum total and HMW adiponectin in patients with type 2 diabetes.

Elevation of serum high molecular weight adiponectin in patients with Type 2 diabetes and orthostatic hypotension: association with arterial stiffness and hypercoagulability

Diabet. Med. 29, 80–87 (2012)

Alterations of plant sterols, lathosterol, oxidative stress and inflammatory markers after the combination therapy of ezetimibe and statin drugs in type 2 diabetic patients

UNLABELLED The elevation of serum plant sterols in addition to serum LDL-cholesterol (LDL-C) is one of the important risk factors for coronary heart disease. We investigated how to alterations of serum hepatic synthesised cholesterol and plant sterols levels, clinical markers for inflammation and oxidative stress after combination therapy with ezetimibe, an inhibitor of cholesterol transporter in the small intestinal colon, and statin drugs in type 2 diabetic patients. Studies were conducted in 28 patients with type 2 diabetes mellitus complicated with dyslipidemia. Patients were divided into 3 groups as follows: the 1st group is 7 patients treated with 10mg ezetimibe sequent on pretreatment with mild statin drug (MS+E group), and the 2nd group is 7 patients treated with 10mg ezetimibe sequent on pretreatment with strong statin drug (SS+E group), and then the 3rd group is 14 patients treated with 10mg ezetimibe alone without pretreatment with any statin drugs (naïve E group). In addition to various metabolic markers, serum plant sterols such as sitosterol and campesterol, and hepatic synthesised cholesterol such as lathosterol were measured by the gas liquid chromatography. Serum highly sensitive CRP (hsCRP) as an inflammation marker, and then malonyldealdehyde (MDA) and carbonyl-modified protein (CMP) as an oxidative stress were assayed by the conventional method, respectively. Fasting plasma glucose and serum glucosylated HbA1c (JDS value) did not show any significant changes after administration of ezetimibe in whole groups. Serum LDL-C was reduced significantly and serum triglyceride exhibited a tendency of reduction in whole groups. Serum sitosterol and campesterol were decreased significantly, while serum lathosterol was increased significantly or markedly in whole patients and also in each group. There were no significant changes in serum hsCRP in whole groups. Both serum MDA and CMP revealed significant or marked reductions in each group. CONCLUSIONS The present investigation suggests that the combination therapy of the ezetimibe and statin drugs is potential to remarkably reduce serum LDL-C, plant sterols, MDA and CMP, and therefore might lead to prevent atherosclerosis.

Effect of canagliflozin on circulating active GLP-1 levels in patients with type 2 diabetes: a randomized trial

Canagliflozin has a robust inhibitory effect on sodium glucose transporter (SGLT)-2 and a mild inhibitory effect on SGLT1. The main purpose of this study was to investigate the effect of canagliflozin on circulating active glucagon-like peptide 1 (GLP-1) levels in patients with type 2 diabetes. Patients were randomly divided into a control group (n =15) and a canagliflozin-treated group (n =15). After hospitalization, the canagliflozin-treated group took 100 mg/day canagliflozin for the entire study, and after 3 days both groups took 20 mg/day teneligliptin for an additional 3 days. In a meal test, canagliflozin significantly decreased the area under curve (AUC) (0-120 min) for plasma glucose (PG) after 3 days when compared with that at baseline, and addition of teneligliptin to the canagliflozin-treated group further decreased it. A significant decrease in the AUC (0-120 min) for serum insulin by canagliflozin was obtained, but the addition of teneligliptin elevated the AUC, and thus abolished the significant difference from baseline. A significant increase in the AUC (0-120 min) of plasma active GLP-1 by canagliflozin-treatment compared with that at baseline was observed, and the addition of teneligliptin resulted in a further increase. However, canagliflozin-treatment did not change the AUC (0-120 min) of plasma active glucose-dependent insulinotropic peptide (GIP). In conclusions, canagliflozin-administration before meals decreased PG and serum insulin, and increased plasma active GLP-1 levels in patients with type 2 diabetes. Canagliflozin did not greatly influence plasma active GIP levels.

Relationship of body fat weight and body fat ratio determined by bioelectric impedance to serum adipocytokines in patients with type 2 diabetes mellitus

SUMMARY OBJECTIVE Various adipocytokines are closely associated with both obesity and insulin resistance. We investigated how body fat weight (BFW) and body fat ratio (BFR) affected serum adipocytokines in patients with type 2 diabetes mellitus. METHODS Studies were conducted in type 2 diabetic patients (n = 41) and age-matched healthy subjects (n = 18). BFW and BFR were determined using a high-frequency bioelectric impedance method. We measured the adipocytokines such as leptin, adiponectin, and tumor necrosis factor (TNF)-α in serum. RESULTS BFW and BFR showed significant positive correlations with BMI and serum leptin concentrations in diabetic patients. A significant positive correlation was found between BFW and serum FFA. Multivariate analysis identified only BMI a significant independent determinant of BFW. Stepwise analysis disclosed a significant positive correlation between HOMA-R and serum leptin. CONCLUSIONS In diabetic patients, accumulation of body fat may increase serum leptin and FFA, which in turn would contribute to insulin resistance.

Circulating SerpinB1 levels and clinical features in patients with type 2 diabetes

Objective The main purpose of this study was to investigate the association of serum SerpinB1 levels and various parameters in patients with type 2 diabetes. The effect of canagliflozin (a sodium glucose cotransporter 2 (SGLT2) inhibitor), which can decrease circulating insulin levels, on serum SerpinB1 levels was also investigated. A recent study suggests that the serum levels of SerpinB1, also known as monocyte neutrophil elastase inhibitor, increase with insulin resistance, may have a protective effect for pancreatic β cells, and may decrease insulin resistance. Research design and methods The study included 30 patients with type 2 diabetes hospitalized for glycemic control and 10 control subjects. Results SerpinB1 levels were significantly higher in patients with type 2 diabetes, compared with that in heathy control subjects (10.01±3.59 vs 5.69±1.64 ng/mL, p<0.0001). Serum SerpinB1 levels had a significant negative correlation with low-density lipoprotein cholesterol (LDL-C) (p=0.0123). Serum SerpinB1 levels had a significant positive association or trend toward a positive association with age and with hemoglobin A1c (HbA1c), and significant negative association with LDL-C levels in some multiple regression analysis models. Patients treated with statins had a tendency toward higher serum SerpinB1 levels, compared with those patients not treated with statins. During a 3-day observation period both with and without canagliflozin treatment, the serum SerpinB1 levels did not change. Conclusions Serum SerpinB1 levels are elevated in patients with type 2 diabetes compared with that in healthy subjects and are negatively correlated with serum LDL-C.

The Effect of Amlodipine on Oxidative Stress in Patients with Type 2 Diabetes

Background. Amlodipine, a calcium channel blocker, is reported to have an antioxidative effect in vitro, but whether such an effect occurs clinically is unknown. The purpose of the study was to investigate the effect of amlodipine (5 mg/day) on oxidative stress by measuring urinary 8-iso-prostaglandin F2α (8-iso-PGF2α), an oxidative stress marker, in patients with type 2 diabetes. The anti-oxidative effect of amlodipine was also assessed using the levels of high-sensitivity C-reactive protein (hsCRP) and fibrinogen. Patients and Methods. Seventeen consecutive patients with type 2 diabetes complicated by hypertension were prospectively enrolled in the study. These patients received amlodipine (5 mg/day) over a 3-month period and various markers were measured before and at the end of this period. Results. Urinary 8-iso-PGF2α showed a tendency to decrease, but the change was not statistically significant (P=.1127). The patients were divided into two groups according to the baseline level of urinary 8-iso-PGF2α, and a significant decrease in 8-iso-PGF2α was found in the group (n=9) with a relatively high baseline 8-iso-PGF2α. There were no changes in hsCRP, fibrinogen, and plasminogen activator inhibitor-1. Significant decreases in systolic and diastolic blood pressure were observed (P<.0001, P=.0151, resp.). Conclusion. The results show that amlodipine (5 mg/day) may provide a clinically useful anti-oxidative effect, based on evaluation of urinary 8-iso-PGF2α.