C. W. Ahn

Prevalence of erectile dysfunction in Korean men with Type 2 diabetes mellitus.

Aims  We investigated the prevalence and risk factors for developing erectile dysfunction (ED) in 1312 Korean men with diabetes in a multicentre study.

Decrease in carotid intima media thickness after 1 year of cilostazol treatment in patients with type 2 diabetes mellitus

A multicenter exploratory study at three university hospitals was performed to evaluate the effect of oral cilostazol on intima media thickness (IMT) in diabetic patients. A total of 141 patients was recruited in this study and randomized into a cilostazol group and a placebo (control) group. One hundred and twenty patients completed the study (i.e. 60 on cilostazol and 60 on placebo). Biochemical profiles and the IMT of the common carotid artery (CCA) determined by high-resolution B-mode ultrasonography were measured at 0, 6, and 12 months after the oral administration of 100--200 mg of cilostazol or placebo (i.e. two or four times daily for 12 months). Clinical and biochemical characteristics, the treatment modality, and microvascular diabetic complications after randomization were not significantly different between the two groups after the study. In the cilostazol treatment group, left CCA average IMT significantly decreased from 0.94+/-0.03 to 0.91+/-0.02 mm at 6 months (P<0.05), and thereafter increased to 0.92+/-0.01 mm (P>0.05) at 12 months, whereas in the control group, it increased from 0.92+/-0.03 to 0.93+/-0.01 mm at 6 months (P>0.05), and to 0.94+/-0.01 mm at 12 months (P>0.05). As for the right CCA average IMT, it decreased from 0.83+/-0.03 to 0.82+/-0.01 mm at 6 months (P<0.05), and to 0.81+/-0.01 mm at 12 months (P<0.05) in the cilostazol group, whereas it increased from 0.87+/-0.03 to 0.89+/-0.01 mm at 6 months (P<0.05), and to 0.90+/-0.01 mm at 12 months (P<0.05) in the control group (P<0.05). After correction for risk factors such as blood pressure, smoking, and lipid profiles, there were significant changes in left and right CCA average IMT for both groups (P<0.05). Left and right CCA average IMT was significantly different between the two groups (P<0.05). After making statistical corrections for blood pressure, smoking, and lipid profiles, the differences between these two groups remained significant (P<0.05). Meanwhile, there were no differences between the groups in the change of risk factors such as BMI, blood pressure, blood sugar, HbA(1c), and lipid profiles. Generally, cilostazol was well tolerated and the most common side effect in the cilostazol group was headache (12/60), mostly early in the treatment regimen. The results suggest that oral cilostazol may be helpful in the treatment of atherosclerosis in type 2 diabetic patients, although conventional cardiovascular risk factors remained unmodified.

Polycystic ovarian syndrome (PCOS) and insulin resistance

Objectives: Polycystic ovary syndrome (PCOS) presents a high risk of developing type 2 diabetes mellitus. We studied a group of women with PCOS and evaluated this defect in insulin action. Methods: The study population consisted of nine PCOS women, six obese type 2 diabetic patients, and five controls whose body mass index (BMI) was similar to that of the nine PCOS women. The 75‐g oral glucose tolerance test (OGTT) and the hyperinsulinemic euglycemic glucose clamp test were performed. Clinical characteristics and the metabolic profiles, including the insulin sensitivity index (ISI), were compared. Results: PCOS women showed significantly elevated insulin responses during OGTT, but their blood glucose levels were comparable with the controls. The subjects with PCOS had more insulin resistance than the other groups. There was no difference among the groups in terms of clinical characteristics and metabolic profiles, except age, luteinzing hormone (LH), testosterone, and sex hormone binding globulin (SHBG). Conclusion: We conclude that PCOS women have significant insulin resistance which is independent of adiposity.

A low-risk ZnT-8 allele (W325) for post-transplantation diabetes mellitus is protective against cyclosporin A-induced impairment of insulin secretion.

SLC30A8 encodes the β-cell-specific zinc transporter-8 (ZnT-8) expressed in insulin secretory granules. The single-nucleotide polymorphism rs13266634 of SLC30A8 is associated with susceptibility to post-transplantation diabetes mellitus (PTDM). We tested the hypothesis that the polymorphic residue at position 325 of ZnT-8 determines the susceptibility to cyclosporin A (CsA) suppression of insulin secretion. INS (insulinoma)-1E cells expressing the W325 variant showed enhanced glucose-stimulated insulin secretion (GSIS) and were less sensitive to CsA suppression of GSIS. A reduced number of insulin granule fusion events accompanied the decrease in insulin secretion in CsA-treated cells expressing ZnT-8 R325; however, ZnT-8 W325-expressing cells exhibited resistance to the dampening of insulin granule fusion by CsA, and transported zinc ions into secretory vesicles more efficiently. Both tacrolimus and rapamycin caused similar suppression of GSIS in cells expressing ZnT-8 R325. However, cells expressing ZnT-8 W325 were resistant to tacrolimus, but not to rapamycin. The Downs syndrome candidate region-1 (DSCR1), an endogenous calcineurin inhibitor, overexpression and subsequent calcineurin inhibition significantly reduced GSIS in cells expressing the R325 but not the W325 variant, suggesting that differing susceptibility to CsA may be due to different interactions with calcineurin. These data suggest that the ZnT-8 W325 variant is protective against CsA-induced suppression of insulin secretion. Tolerance of ZnT-8 W325 to calcineurin activity may account for its protective effect in PTDM.

Lobeglitazone and pioglitazone as add‐ons to metformin for patients with type 2 diabetes: a 24‐week, multicentre, randomized, double‐blind, parallel‐group, active‐controlled, phase III clinical trial with a 28‐week extension

We aimed to compare the efficacy and safety of lobeglitazone and pioglitazone as add‐ons to metformin in patients with type 2 diabetes. Patients who were inadequately controlled by metformin were randomized and treated once daily with either lobeglitazone (0.5 mg, n = 128) or pioglitazone (15 mg, n = 125) for 24 weeks, with a 28‐week extension trial of lobeglitazone treatment in patients who consented. The primary endpoint was the change in glycated haemoglobin (HbA1c) concentration from baseline to week 24. At week 24, the mean change from baseline in HbA1c was −0.74% for the lobeglitazone group and −0.74% for the pioglitazone group, with a mean difference of 0.01% [95% confidence interval (CI) of difference, −0.16 to 0.18]. The effects of lobeglitazone on lipid variables and the adverse events associated with lobeglitazone were similar to those observed with pioglitazone. Lobeglitazone was not inferior to pioglitazone as an add‐on to metformin in terms of their efficacy and safety.

Insulin sensitivity in physically fit and unfit children of parents with Type 2 diabetes

Aims  First‐degree relatives of patients with Type 2 diabetes mellitus (T2DM) are often reported to be insulin resistant. We wanted to identify early metabolic abnormalities in this condition, and determine whether they are altered by regular physical training.

The association between pulse wave velocity and metabolic syndrome and adiponectin in patients with impaired fasting glucose: Cardiovascular risks and adiponectin in IFG

We aimed to assess how metabolic profiles, surrogate markers of insulin resistance, and subclinical atherosclerosis are interrelated in subjects with impaired fasting glucose (IFG) and investigate whether the diagnosis of metabolic syndrome (MetS) further increases the risk of cardiovascular disease among subjects already at risk. We analyzed 1739 Korean subjects with IFG. The parameters of MetS, plasma adiponectin level, and pulse wave velocity (PWV) were assessed. Subjects with MetS had unfavorable metabolic parameters, lower adiponectin level, and higher peripheral PWV compared to those without MetS. Adiponectin correlated with fasting glucose, waist circumference, triglyceride, HDL-cholesterol, BMI, HOMA-IR, and the number of MetS components. In addition to blood pressure, peripheral PWV was associated with triglyceride, waist circumference, and the number of MetS components while aortic PWV correlated positively with fasting plasma glucose. Multiple linear regression analysis revealed that adiponectin correlated with HDL-cholesterol, HOMA-IR, fasting glucose, waist circumference, and triglyceride, peripheral PWV with blood pressure, body mass index, waist circumference, and the number of MetS components, and aortic PWV with fasting plasma glucose. In subjects with IFG, concurrent MetS increases PWV and has an unfavorable effect on cardiovascular risks, and these risks were further increased by additional MetS components.

Mutation in hepatocyte nuclear factor-1α is not a common cause of MODY and early-onset type 2 diabetes in Korea

Abstract Maturity-onset diabetes of the young (MODY)-3 with a mutation in hepatocyte nuclear factor (HNF)-1α has been identified in most races, but the prevalence of Korean MODY and early-onset type 2 diabetes with a mutation in this gene is unknown. To determine the prevalence of MODY and early-onset type 2 diabetes with the mutation of HNF-1α gene in Korea, we analyzed this gene in 69 Korean early-onset type 2 diabetics and in 35 healthy persons using the single-strand conformation polymorphism (SSCP) technique and direct sequencing. We identified one mutation in exon 4 (C900A) in only one of the 69 Korean subjects with early-onset type 2 diabetes; this mutation was silent and did not change the amino acid (Pro300). Additionally, we identified four polymorphisms: S487N, AAC→AGC, intron 2 (nt −23), intron 7: (nt +7) and intron 9 (nt −24). However, there was no significant difference in frequencies of the four polymorphisms between the type 2 diabetes and control groups. Among type 2 diabetics, codon 487 variant showed no relationship to age at onset, body mass index, fasting blood glucose. HbA1c, lipid profile, basal C-peptide and 2 hour C-peptide. We concluded that this genetic mutation in HNF-1α gene may not be a common contributor to MODY and early-onset type 2 diabetes susceptibility in Korea.

The effect of rosiglitazone on insulin sensitivity and mid‐thigh low‐density muscle in patients with Type 2 diabetes

Diabet. Med. 27, 30–36 (2010)

Clinical characteristics, GAD antibody (GADA) and change of C-peptide in Korean young age of onset diabetic patients

Aims To investigate the association of clinical and immunological markers with diabetes classification in newly diagnosed young diabetic patients at disease onset.