Investigation of 2 models to set and evaluate quality targets for hb a1c: biological variation and sigma-metrics.

BACKGROUND: A major objective of the IFCC Task Force on Implementation of HbA1c Standardization is to develop a model to define quality targets for glycated hemoglobin (Hb A1c). METHODS: Two generic models, biological variation and sigma-metrics, are investigated. We selected variables in the models for Hb A1c and used data of external quality assurance/proficiency testing programs to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories. RESULTS: In the biological variation model, 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the sigma-metrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP), 77% of the individual laboratories and 12 of 26 instrument groups met the 2σ criterion. CONCLUSIONS: The biological variation and sigma-metrics models were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The sigma-metrics model is more flexible, as both the TAE and the risk of failure can be adjusted to the situation-for example, requirements related to diagnosis/monitoring or international authorities. With the aim of reaching (inter)national consensus on advice regarding quality targets for Hb A1c, the Task Force suggests the sigma-metrics model as the model of choice, with default values of 5 mmol/mol (0.46%) for TAE and risk levels of 2σ and 4σ for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes.

Efficacy and safety of liraglutide monotherapy compared with metformin in Japanese overweight/obese patients with type 2 diabetes.

There is little information on direct comparison between metformin and glucagon-like peptide-1 (GLP-1) receptor agonists in the Asian population. This study examined the efficacy and safety of liraglutide monotherapy compared with metformin monotherapy in overweight/obese Japanese patients with type 2 diabetes (T2DM). The study was a 24-week, open-labeled, randomized controlled study. Overweight or obese patients with T2DM aged 20-75 years with suboptimal glycemic control were randomized to liraglutide or metformin monotherapy. The primary endpoint was change in HbA1c at week 24. Secondary endpoints included changes in daily glycemic profile, body weight, incidence of hypoglycemia and other adverse events. The study, which was originally planned to enroll 50 subjects in each group, was ended with insufficient recruitment. A total of 46 subjects completed the study, and analysis was conducted in this cohort. Reduction in HbA1c at week 24 was comparable between the metformin (n = 24) and liraglutide (n = 22) groups (-0.95 ± 0.80% vs. -0.80 ± 0.88%, p = 0.77), while the liraglutide group reached maximal reduction more rapidly than did the metformin group. There was no significant difference in weight gain or incidence of hypoglycemia between the groups. Diarrhea was more frequent in the metformin group, while constipation was more frequent in the liraglutide group. There was no significant difference in treatment satisfaction between the groups. In conclusion, liraglutide and metformin monotherapy showed similar reduction in HbA1c during 24 weeks, with no difference in weight gain or incidence of hypoglycemia in overweight or obese Japanese patients with T2DM.

Conophylline suppresses hepatic stellate cells and attenuates thioacetamide-induced liver fibrosis in rats.

BACKGROUND & AIMS: Conophylline (CnP) is a vinca alkaloid purified from a tropical plant and inhibits activation of pancreatic stellate cells. We investigated the effect of CnP on hepatic stellate cells (HSC) in vitro. We also examined whether CnP attenuates hepatic fibrosis in vivo. METHOD: We examined the effect of CnP on the expression of α-smooth muscle actin (α-SMA) and collagen-1, DNA synthesis and apoptosis in rat HSC and Lx-2 cells. We also examined the effect of CnP on hepatic fibrosis induced by thioacetamide (TAA). RESULTS: In rat HSC and Lx-2 cells, CnP reduced the expression of α-SMA and collagen-1. CnP inhibited DNA synthesis induced by serum. CnP also promoted activation of caspase-3 and induced apoptosis as assessed by DNA ladder formation and TUNEL assay. In contrast, CnP did not induce apoptosis in AML12 cells. We then examined the effect of CnP on TAA-induced cirrhosis. In TAA-treated rats, the surface of the liver was irregular and multiple nodules were observed. Histologically, formation of pseudolobules surrounded by massive fibrous tissues was observed. When CnP was administered together with TAA, the surface of the liver was smooth and liver fibrosis was markedly inhibited. Collagen content was significantly reduced in CnP-treated liver. CONCLUSION: Conophylline suppresses HSC and induces apoptosis in vitro. CnP also attenuates formation of the liver fibrosis induced by TAA in vivo.

Inhibition of NO-induced ß-cell death by novel NF-κB inhibitor (-)-DHMEQ via activation of Nrf2-ARE pathway.

Excessive nitric oxide (NO) plays a pivotal role in the progression of ß-cell apoptosis in type 1 diabetes mellitus. We used mouse insulinoma Min6 cells as a model of ß cells in this research. We found that (-)-DHMEQ, an NF-κB inhibitor, rescued ß cells from NO-induced apoptosis, and then studied the mechanism of apoptosis inhibition. (-)-DHMEQ activated Nrf2 and induced transcription of Nrf2-target genes following the increase of antioxidant response element (ARE) reporter activity. Similarly, tert-butyl hydroquinone (tBHQ), a known activator of Nrf2, inhibited NO-induced cell death along with the transcriptional activation of ARE. RNAi-mediated knockdown of Nrf2 lowered the cytoprotective effect of (-)-DHMEQ against NO, suggesting that (-)-DHMEQ inhibited NO-induced cell death via Nrf2 activation. Furthermore, overexpression of Nrf2 rendered cells to be more resistant to NO, indicating that Nrf2 activation provides critical defense function against NO in Min6 cells. Taken together, we conclude that (-)-DHMEQ may be a useful therapeutic agent for type 1 diabetes mellitus in the onset of disease by protecting ß cells from apoptosis.

[Chairmen's introductory remarks].

Diagnostic criteria in diabetes mellitus has been revised after 11 years. In addition to previous diagnostic criteria, HbAlc was added to the new criteria as a biomarker of chronic diabetes. Although NGSP >6.5 has become a marker of diabetes, the equation of HbA1c (NGSP) = 1.02 x HbA1c (JDS) + 0.25% was reported by analysis of global standardization. According to this equation, HbA1c (NGSP) 6.5% corresponded to HbA1c (JDS) 6.1%. In this symposium, we presented the viewpoint of the Japanese Society of Diabetes Mellitus for standardization of HbAlc and the issue of using NGSP instead of JDS.

[The significance of high sensitive C reactive protein as a risk factor for cardiovascular diseases].

Chronic inflammation is involved in the pathogenesis of cardiovascular diseases (CVD). Several prospective studies have indicated that an elevated high sensitive C-reactive protein (hs-CRP) level is a risk factor for CVD. These results were also confirmed by prospective studies in Japan both for primary and secondary prevention. A randomized control study using statins also revealed that lower levels of both LDL cholesterol and hs-CRP were independently related to the incidence of CVD. Recent meta-analysis revealed that hs-CRP was a risk factor not only for CVD but for other diseases including cancers. It revealed that the absolute value of hs-CRP varied among the study populations. The mechanism of how hs-CRP is associated with the pathogenesis of CVD is not fully understood. Generally, inflammation in the vascular wall and the release of inflammatory cytokines from macrophages was considered to the main mechanism, but infection with such as chlamydia or Helicobacter pylori, and periodontal disease have been postulated as the causes of systemic inflammation. Recently, visceral fat accumulation and its cross-interaction with inflammatory cells have been proposed as the cause of systemic inflammation as "innate inflammation". Our original cross sectional studies also showed the correlations of hs-CRP with BMI and triglyceride. Although there is no specific therapy for the reduction of hs-CRP, we have to consider hs-CRP as a risk factor for CVD which complements other classical risk factors.

Effects of olmesartan medoxomil, an angiotensin II type 1 receptor antagonist, on plasma concentration of B-type natriuretic peptide, in hypertensive patients with type 2 diabetes mellitus: a preliminary, observational, open-label study.

BACKGROUND AND OBJECTIVE: Angiotensin II type 1 (AT1) receptor antagonists (angiotensin receptor blockers [ARBs]) are widely used for the treatment of not only hypertension but also cardiac dysfunction. B-type natriuretic peptide (BNP) is secreted mainly by the cardiac ventricle and plays an important role in the regulation of blood pressure (BP) and body fluid. It has been established that the plasma level of BNP is increased in patients with chronic heart failure in proportion to the severity of cardiac dysfunction. Because cardiac dysfunction is closely associated with a high risk of mortality in patients with diabetes mellitus, early identification and prevention of cardiac dysfunction are important. The objective of this study was to determine the effects of olmesartan medoxomil, a novel ARB, on the plasma level of BNP in hypertensive patients with type 2 diabetes. METHODS: This was a preliminary, prospective, observational, open-label study. Sixty-eight type 2 diabetic patients with hypertension (systolic BP [SBP]≥140 mmHg or diastolic BP [DBP]≥90 mmHg) received olmesartan medoxomil 10­20 mg/day for 24 weeks. Plasma levels of BNP, as well as several clinical parameters of glycaemic control and lipid metabolism, were compared before and after 24 weeks of treatment. Another group consisting of 22 age- and body mass index-matched subjects not treated with olmesartan medoxomil was observed for reference purposes. RESULTS: In the olmesartan medoxomil group, mean±SD SBP decreased from 152.8±16.4 at baseline to 146.8±14.4 mmHg after 24 weeks' treatment (p<0.05); similarly, mean±SD DBP decreased from 85.6±10.5 to 81.3±11.6 mmHg (p<0.05). In 53 subjects in whom plasma levels of BNP could be measured both before and after treatment, mean±SD BNP decreased from 41.3±49.9 to 32.5±36.3 pg/mL (p<0.05). Change in plasma BNP level over the 24-week treatment period in the olmesartan medoxomil group was not correlated with change in SBP or DBP. Multiple regression analysis revealed that change in plasma BNP level was not correlated with baseline value of or change in any other parameters. No other parameters in the olmesartan medoxomil group, and no parameters in the non-olmesartan medoxomil reference group, showed significant changes. CONCLUSION: The current preliminary study showed that olmesartan medoxomil treatment might decrease plasma BNP levels, independent of its BP-lowering effect, in hypertensive patients with type 2 diabetes.

Preparation of conophylline affinity nano-beads and identification of a target protein.

Conophylline, a vinca alkaloid extracted from the tropical plant Ervatamia microphylla, has been shown to induce the differentiation of insulin-producing beta-cells in cultured cells and in animals. However, its mechanism of action and the molecular target have remained unclear. Therefore, we prepared a fishing probe with conophylline to identify the target protein by using latex nano-beads, which are newly innovated tools for affinity-purification. With these conophylline-linked nano-beads, we found that conophylline directly interacted with ARL6IP. ARL6IP may thus be involved in the mechanism of cellular differentiation of beta-cells, and this probe should be useful to find other target proteins.

Administration of conophylline and betacellulin-delta4 increases the beta-cell mass in neonatal streptozotocin-treated rats.

The present study was conducted to examine the effect of administration of conophylline (CnP) and betacellulindelta4 (BTCdelta4) on the beta-cell mass in neonatal streptozotocin-treated rats (neonatal STZ rats). STZ (100 microg/g) was injected into neonatal rats, and then CnP (2 microg/g) and/or BTCdelta4 (200 pmol/g) were administered to neonatal STZ rats for 1 week. The plasma glucose concentration was monitored, and an intraperitoneal glucose tolerance test (ipGTT) was performed on day 8 and at 8 weeks after the STZ injection. In neonatal STZ rats treated with control solution (S group), the plasma glucose concentration increased for several days after the STZ injection, returned to nearly normal levels, and then increased gradually after six weeks of age. Eight weeks after the STZ-injection, the plasma glucose concentration was increased significantly compared to that of normal rats. The glucose response to ipGTT was significantly reduced in neonatal STZ rats treated with CnP (CnP group), BTCdelta4 (delta4 group) and CnP+BTCdelta4 (CnP+delta4 group). The beta-cell mass and the insulin content of the pancreas were significantly increased in the CnP group and delta4 group. The effect of CnP+delta4 was greater than that of CnP alone or BTCdelta4 alone. CnP+BTCdelta4 significantly increased the number of PDX-1-positive ductal cells and the number of insulin/BrdU double-positive ductal cells. These results indicate the efficacy of CnP and BTCdelta4 in increasing the beta-cells mass of neonatal STZ-treated rats.

Insulin intervention in slowly progressive insulin-dependent (type 1) diabetes mellitus.

OBJECTIVE: We tested the hypothesis that insulin therapy rather than sulfonylurea (SU) treatment is preferable to reverse or preserve beta-cell function among patients with slowly progressive insulin-dependent (type 1) diabetes (SPIDDM) or latent autoimmune diabetes in adults. METHODS: This multicenter, randomized, nonblinded clinical study screened 4089 non-insulin-dependent diabetic patients for glutamic acid decarboxylase autoantibodies (GADAb). Sixty GADAb-positive non-insulin-requiring diabetic patients with a 5-yr duration or shorter of diabetes were assigned to either the SU group (n = 30) or the insulin group (n = 30). Serum C-peptide responses to annual oral glucose tolerance tests were followed up for a mean of 57 months. The primary endpoint was an insulin-dependent state defined by the sum of serum C-peptide values during the oral glucose tolerance test (SigmaC-peptide) less than 4 ng/ml (1.32 nmol/liter). RESULTS: The progression rate to an insulin-dependent state in the insulin group (three of 30, 10%) was lower than that in the SU group (13 of 30, 43%; P = 0.003, log-rank). Longitudinal analysis demonstrated that SigmaC-peptide values were better preserved in the insulin group than in the SU group. Multiple regression analysis demonstrated that insulin treatment, a preserved C-peptide response, and a low GADAb titer at entry were independent factors in preventing progression to an insulin-dependent state. Subgroup analysis suggested that insulin intervention was highly effective for SPIDDM patients with high GADAb titers [> or =10 U/ml (180 World Health Organization U/ml)] and preserved beta-cell function [SigmaC-peptide > or = 10 ng/ml (3.31 nmol/liter)] at entry. No severe hypoglycemic episodes occurred during the study. CONCLUSIONS: Insulin intervention to preserve beta-cell function is effective and safe for patients with SPIDDM or latent autoimmune diabetes in adults.

Effects of DHMEQ, a novel nuclear factor-kappab inhibitor, on beta cell dysfunction in INS-1 cells.

AIMS: Recent studies suggest that nuclear factor-kappaB (NF-kappaB) activation has an important role in leading to beta cell dysfunction in both type 1 and type 2 diabetes. In this study we tested this hypothesis by investigating the effects of dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-kappaB inhibitor, on tumor necrosis factor-alpha (TNF-alpha)-induced beta cell dysfunction. METHODS: INS-1 cells were incubated with TNF- alpha and with or without DHMEQ for 24 hours. Glucose-stimulated insulin secretion, cell viability, mRNA expression and NF-kappaB activation were investigated. RESULTS: DHMEQ suppressed TNF-alpha-induced NF-kappaB activation and partially ameliorated glucose-stimulated insulin secretion in a dose-dependent manner. DHMEQ also partially ameliorated decreased cell viability and insulin mRNA level induced by TNF-alpha. CONCLUSION: DHMEQ suppressed NF-kappaB activation and ameliorated beta cell dysfunction induced by TNF- alpha. Inhibition of activated NF-kappaB in beta cells may be important to ameliorate beta cell dysfunction in diabetes.

A simple method to induce differentiation of murine bone marrow mesenchymal cells to insulin-producing cells using conophylline and betacellulin-delta4.

The present study was conducted to establish a method to induce differentiation of bone marrow (MB)-derived mesenchymal cells into insulin-producing cells. When mouse BM-derived mesenchymal cells were cultured for 60 days in medium containing 10% fetal calf serum and 25 mM glucose, they expressed insulin. Addition of activin A and betacellulin (BTC) accelerated differentiation, and immunoreactive insulin was detected 14 days after the treatment. Insulin-containing secretory granules were observed in differentiated cells by electron microscopy. Treatment of BM-derived mesenchymal cells with conophylline (CnP) and BTC-delta4 further accelerated differentiation, and mRNA for insulin was detected 5 to 7 days after the treatment. Mesencymal cells treated with CnP and BTC-delta4 responded to a high concentration of glucose and secreted mature insulin. When these cells were transplanted into streptozotocin-treated mice, they markedly reduced the plasma glucose concentration, and the effect continued for at least 4 weeks. These results indicate an efficacy of the combination of CnP and BTC-delta4 in inducing differentiation of BM-derived mesenchymal cells into insulin-producing cells.

The number of microvascular complications is associated with an increased risk for severity of periodontitis in type 2 diabetes patients: Results of a multicenter hospital-based cross-sectional study.

AIMS/INTRODUCTION: To explore the relationships between periodontitis and microvascular complications as well as glycemic control in type 2 diabetes patients. MATERIALS AND METHODS: This multicenter, hospital-based, cross-sectional study included 620 patients with type 2 diabetes. We compared the prevalence and severity of periodontitis between patients with ≥1 microvascular complication and those without microvascular complications. We also compared the prevalence and severity of periodontitis among patients with different degrees of glycemic control. RESULTS: After adjusting for confounding factors, multiple logistic regression analysis showed that the severity of periodontitis was significantly associated with the number of microvascular complications (odds ratio 1.3, 95% confidence interval 1.1-1.6), glycated hemoglobin ≥8.0% (64 mmol/mol; odds ratio 1.6; 95% confidence interval 1.1-2.3), and older age (≥50 years; odds ratio 1.7; 95% confidence interval 1.1-2.6). However, the prevalence of periodontitis was not significantly associated with the number of microvascular complications, but was associated with male sex, high glycated hemoglobin (≥8.0% [64 mmol/mol]), older age (≥40 years), longer duration of diabetes (≥15 years) and fewer teeth (≤25). Furthermore, propensity score matching for age, sex, diabetes duration and glycated hemoglobin showed that the incidence of severe periodontitis was significantly higher among patients with microvascular complications than among those without microvascular complications (P < 0.05). CONCLUSIONS: The number of microvascular complications is a risk factor for more severe periodontitis in patients with type 2 diabetes, whereas poor glycemic control is a risk factor for increased prevalence and severity of periodontitis.

Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry-recommended reference measurement procedure and reference materials for glycated albumin determination.

BACKGROUND: Glycated albumin is an intermediate glycaemic control marker for which there are several measurement procedures with entirely different reference intervals. We have developed a reference measurement procedure for the purpose of standardizing glycated albumin measurements. METHODS: The isotope dilution liquid chromatography/tandem mass spectrometry method was developed as a reference measurement procedure for glycated albumin. The stable isotopes of lysine and fructosyl-lysine, which serve as an internal standard, were added to albumin isolated from serum, followed by hydrogenation. After hydrolysis of albumin with hot hydrochloric acid, the liberated lysine and fructosyl-lysine were measured by liquid chromatography/tandem mass spectrometry, and their concentrations were determined from each isotope ratio. The reference materials (JCCRM611) for determining of glycated albumin were prepared from pooled patient blood samples. RESULTS: The isotope dilution-tandem mass spectrometry calibration curve of fructosyl-lysine and lysine showed good linearity (r = 0.999). The inter-assay and intra-assay coefficient of variation values of glycated albumin measurement were 1.2 and 1.4%, respectively. The glycated albumin values of serum in patients with diabetes assessed through the use of this method showed a good relationship with routine measurement procedures (r = 0.997). The relationship of glycated albumin values of the reference material (JCCRM611) between these two methods was the same as the relationship with the patient serum samples. CONCLUSION: The Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry recommends the isotope dilution liquid chromatography/tandem mass spectrometry method as a reference measurement procedure, and JCCRM611 as a certified reference material for glycated albumin measurement. In addition, we recommend the traceability system for glycated albumin measurement.