Shizuo Kajiyama

Hydrogen-rich pure water prevents superoxide formation in brain slices of vitamin C-depleted SMP30/GNL knockout mice.

Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogens effect in the brain, we administered hydrogen-rich pure water (H(2)) to senescence marker protein-30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H(2), VC, or pure water (H(2)O), administered for 33 days. VC levels in H(2) and H(2)O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H(2) group subjected to ischemia-reperfusion than in the H(2)O group. Thus hydrogen-rich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation.

Defect of the First-Phase Insulin Secretion to Glucose Stimulation in the Perfused Pancreas of the Nonobese Diabetic (NOD) Mouse

To investigate the development of impaired insulin secretion in type I diabetes mellitus, the pancreata of ICR and NOD mice (10–50 wk of age) were perfused. According to insulin responses to 30 mM glucose and to 19 mM arginine, we classified the NOD mice into four groups: those having normal insulin secretion to glucose and to arginine similar to that of control ICR mice (group 1); those with a defect in the first-phase insulin secretion to glucose stimulation but with almost normal insulin secretion to arginine, total insulin release to glucose being significantly smaller than that of group 1 (group 2); those having only a small insulin response to either stimulus, but a fasting plasma glucose level still within the normal range (group 3); and those being overtly diabetic, showing no insulin response to either stimulus (group 4). The severity of insulitis and insulin concentration of the pancreas in each group of NOD mice was well correlated with the insulin release from the perfused pancreas. These results indicate that the initial sign of B-cell damage in NOD mice is a defect of the first phase of glucose-induced insulin secretion, which is followed by a total loss of ability to respond to glucose or arginine stimulation.

Antibodies to Glutamic Acid Decarboxylase in Japanese Diabetic Patients with Secondary Failure of Oral Hypoglycaemic Therapy

Some patients with non‐insulin‐dependent (Type 2) diabetes mellitus (NIDDM) are positive for antibodies to glutamic acid decarboxylase (anti‐GAD), which have been shown to be a useful marker for the diagnosis and prediction of insulin‐dependent (Type 1) diabetes mellitus (IDDM). Anti‐GAD positive NIDDM patients tend to develop insulin deficiency. We investigated the prevalence of anti‐GAD in 200 NIDDM with secondary failure of oral hypoglycaemic therapy (SF) and 200 NIDDM well controlled by diet and/or sulphonylurea agents (NSF). Twenty‐two of 200 (11 %, p < 0.05) SF patients and 6 of 200 (3 %) NSF patients were anti‐GAD positive. The positive rate for anti‐GAD was as high as 23.8 % in the non‐obese and insulin deficient SF patients. The SF patients with anti‐GAD tended to be non‐obese and to have an impaired release of endogenous insulin. The interval before development of secondary failure was not associated with the presence of anti‐GAD in this study. In conclusion we found that anti‐GAD was positive in as many as 11 % of the SF patients, suggesting that autoimmune mechanisms may play an important role in the pathogenesis of secondary failure of sulphonylurea therapy.

Eating vegetables before carbohydrates improves postprandial glucose excursions

Large fluctuations in blood glucose are reported to promote the micro- and macrovascular complications associated with Type 2 diabetes. Postprandial plasma glucose and glycaemic spikes are more strongly associated with atherosclerosis than fasting plasma glucose or HbA1c level 1. Therefore, safe and effective interventions, including diet, are needed to reduce glycaemic variability and minimize hypoglycaemic events. The continuous glucose monitoring system is capable of detecting hypoglycaemia and hyperglycaemia that may be undetectable by self monitoring blood glucose and HbA1c 2. In particular, the mean amplitude of glycaemic excursions is a significant determinant of overall metabolic control, as well as increased risk of diabetes complications. We reported acute effects of eating vegetables before carbohydrates on postprandial glucose and insulin levels 3 and the long-term glycaemic improvements in patients with Type 2 diabetes 4. The method of the education included nutritional advice given in the form of a simple and easy meal plan of eating vegetables before carbohydrates. In order to reduce postprandial hyperglycaemia, patients were encouraged to consume every meal by eating vegetables prior to carbohydrates. In this study we evaluated whether eating vegetables before carbohydrates could reduce the daily postprandial glucose excursions assessed by continuous glucose monitoring system in Japanese patients with Type 2 diabetes and subjects with normal glucose tolerance. Consecutive patients with Type 2 diabetes were recruited among outpatients regularly attending a diabetes clinic, the Kajiyama Clinic located in Kyoto, Japan, from 2011 to 2012. Diagnosis of diabetes was made according to the World Health Organization criteria. Confirmation of normal glucose tolerance was based on fasting blood glucose < 5.6 mmol/l and 2-h glucose concentration in an oral glucose tolerance test < 7.8 mmol/l. All participants were assigned to perform the continuous glucose monitoring system (CGMS, Medtronic Minimed Gold; Medtronic Minimed, Northridge, CA, USA) for 72 h by eating test meals of vegetables before carbohydrates and carbohydrates before vegetables on the 2nd and the 3rd day in a randomized crossover design. The test meals consisted of rice/bread, meat/fish and 500 g of vegetables, and contained 21 g of dietary fibre and 125.6 kJ kg−1 per day. The energy ratio of protein, fat and carbohydrates was 17, 25 and 58%, respectively. The subjects ate the first dish of vegetables for 5 min, then the main dishes, and consumed rice or bread with a 10-min interval between vegetables and carbohydrates in each meal, and then vice versa. The glucose fluctuations were assessed by the following parameters obtained from the continuous glucose monitoring system and compared between the day of eating vegetables before carbohydrates and the day of eating the carbohydrates before the vegetables: the mean plasma glucose, standard deviation (sd), mean amplitude of glycaemic excursions and the largest amplitude of glycaemic excursions, postprandial plasma glucose, incremental area under the curve 0–3h (IAUC0–3h), and incremental glucose peak. Nineteen outpatients with Type 2 diabetes [men/women 6/13; age 65.5 ± 9.4 years, duration of diabetes 16.4 ± 10.2 years; BMI 22.5 ± 3.1 kg/m2; HbA1c 55.0 ± 10.9 mmol/mol (7.2 ± 1.0%); fasting plasma glucose 8.06 ± 2.67 mmol/l, diet/oral hypoglycaemic agents/insulin + oral hypoglycaemic agents 3/3/13; mean ± sd or n] and 21 subjects with normal glucose tolerance [men/women 2/19; age 29.8 ± 11.3 years; BMI 20.8 ± 3.0 kg/m2; HbA1c 36.0 ± 6.6 mmol/mol (5.4 ± 0.6%); fasting plasma glucose 4.89 ± 0.50 mmol/l] were enrolled in the study. The levels of standard deviation, mean amplitude of glycaemic excursions, largest amplitude of glycaemic excursions, 1-h postprandial plasma glucose of breakfast, IAUC0–3h of lunch and dinner, mean IAUC0–3h and incremental glucose peak were significantly reduced when the participants ate vegetables before carbohydrates compared with the reverse regimen in both subjects with Type 2 diabetes and those with normal glucose tolerance; however, the values of mean plasma glucose were not different in either of the subject groups (Table 1). Two-hour postprandial plasma glucose levels of lunch and dinner, and IAUC0–3h of breakfast were also significantly reduced in patients with Type 2 diabetes, while 1-h postprandial plasma glucose levels of lunch and dinner were significantly decreased in subjects with normal glucose tolerance. The reason for the reduction of postprandial plasma glucose levels by eating vegetables before carbohydrates can be explained, partly, by the dietary fibre content in the vegetables taken before the carbohydrates. Dietary carbohydrates consumed after vegetables were digested slowly and required less insulin for subsequent metabolic disposal 5. Other factors may influence the glycaemic response and digestion of carbohydrates in the small intestine, including the rate of digestion, cooking method, transit time and rate of intestinal absorption. Vegetables given before carbohydrates might stimulate incretin hormone secretion, which leads to the reduction in glycaemic excursions 6. Table 1 Characteristics of glycaemic excursion in subjects with Type 2 diabetes and normal glucose tolerance In this study, we demonstrated that eating vegetables before carbohydrates reduced the postprandial glucose excursions compared with the reverse regimen in both subjects with Type 2 diabetes and those with normal glucose tolerance using continuous glucose monitoring system for the first time. The result of this study is important because eating vegetables before carbohydrates could be a novel method to reduce the incidence of cardiovascular disease 7–10. As one of the educational points in nutrition, the advice to patients with Type 2 diabetes should be to eat vegetables before carbohydrates, and this advice could even be applicable to healthy subjects in order to prevent future cardiovascular events.

Effect of eating vegetables before carbohydrates on glucose excursions in patients with type 2 diabetes

The aim of this review was to evaluate whether eating vegetables before carbohydrates could reduce the postprandial glucose, insulin, and improve long-term glycemic control in Japanese patients with type 2 diabetes. We studied the effect of eating vegetables before carbohydrates on postprandial plasma glucose, insulin, and glycemic control for 2.5 y in patients with type 2 diabetes. The postprandial glucose and insulin levels decreased significantly when the patients ate vegetables before carbohydrates compared to the reverse regimen, and the improvement of glycemic control was observed for 2.5 y. We also compared the postprandial glucose and glucose fluctuations assessed by continuous glucose monitoring system for 72-h in patients with type 2 diabetes and subjects with normal glucose tolerance when subjects ate vegetables before carbohydrates and carbohydrates before vegetables in a randomized crossover design. The glycemic excursions and incremental glucose peak were significantly lower when the subjects ate vegetables before carbohydrates compared to the reverse regimen. This evidence supports the effectiveness of eating vegetables before carbohydrates on glucose excursions in the short-term and glycemic control in the long-term in patients with type 2 diabetes.

Intervention with Delivery of Diabetic Meals Improves Glycemic Control in Patients with Type 2 Diabetes Mellitus

The aim of this study was to investigate the effects of a diabetic meal delivery system on glycemic control over a 12 month period in patients with type 2 diabetes. A total of 77 patients with type 2 diabetes were assigned randomly into three dietary intervention groups: group M, diabetic meal delivery; group D, individual dietary counseling; and group C, conventional dietary education. In group M, HbA1c levels decreased significantly from 8.2 ± 1.2% to 7.4 ± 0.8% after 12 months (p<0.05), while in group D, HbA1c levels decreased significantly throughout the entire 12 month period, from 8.5 ± 1.7% at baseline to 7.4 ± 1.1% at the endpoint. Similarly, fasting blood glucose (FBG) levels decreased significantly between 1 and 12 months in group M (p<0.05), and decreased significantly during the entire 12 month period in group D (p<0.01). There were no significant changes in either HbA1c or FBG levels in group C. This study provides evidence that intervention with delivery of diabetic meals to patients with type 2 diabetes can be equally effective for achieving glycemic control as individual dietary counselling by a dietitian. Diabetic meal delivery can therefore be used successfully to provide diabetes education to outpatients.

The α-glucosidase inhibitor acarbose reduces the net electronegative charge of low-density lipoprotein in patients with newly diagnosed type 2 diabetes

BACKGROUND Several epidemiological studies have shown that postprandial hyperglycemia is associated with an increased risk of cardiovascular disease (CVD). The present study was conducted in order to compare the effects of acarbose and glimepiride treatment on serum lipoprotein profiles in patients with type 2 diabetes. METHODS A total of 37 patients with newly diagnosed type 2 diabetes were studied. The patients were assigned randomly to treatment for 12 weeks with either acarbose (n=13, 100 mg x 3/day, group A), glimepiride (n=13, 2 mg/day, group G) or diet only (n=11, group D). Lipid and lipoprotein profiles before and after each treatment were evaluated. RESULTS A significant reduction in the net electronegative charge of low-density lipoprotein (emLDL) was observed in group A (-1.8, P<0.01), whereas no significant change in emLDL was observed in groups G and D. In group A, small VLDL and very small LDL levels were also decreased significantly (P<0.05). The change in emLDL levels correlated significantly with changes in very small LDL (r=0.751, P<0.01) and oxidized LDL levels (r=0.623, P<0.05). CONCLUSION These results suggest that measurement of serum emLDL may be a sensitive and clinically useful marker for determining qualitative lipoprotein abnormalities in diabetes, and that acarbose treatment lowers CVD risk by decreasing production of emLDL.

HLA-DRB1 Alleles Contribute to Determining the Prognosis of Japanese Diabetes Mellitus Positive for Antibodies to Glutamate Decarboxylase

Diabetes mellitus positive for antibodies to glutamate decarboxylase is heterogeneous as far as the degree of impairment of endogenous insulin release, though antibodies to glutamate decarboxylase are the most useful marker for future insulin deficiency. To investigate what determines the prognosis of diabetes mellitus positive for antibodies to glutamate decarboxylase, we measured HLA-DRB1 alleles in three groups: 77 cases of insulin-dependent diabetes mellitus (IDDM), 44 of non-insulin-dependent diabetes mellitus (NIDDM) with secondary failure of oral hypoglycemic therapy, and 22 of NIDDM well controlled by diet and/or sulfonylurea agents. The proportion of susceptible and resistant alleles to IDDM determined the degree of insulin deficiency, and comparison of IDDM to NIDDM well controlled by diet and/or sulfonylurea agents revealed significant differences in DRB1*0405 (P < 0.05; RR = 2.82 and RR = 0.89, respectively) and DRB1*1502 (P < 0.001; RR = 0.02 and RR = 2.19, respectively). This study revealed that HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.

Insulin Release from Column-Perifused Isolated Islets of Uremic Rats

In order to examine the insulin secretion in chronic renal failure, isolated pancreatic islets either from uremic rats or from control rats were mixed into a short column of Bio-Gel P-2 polyacrylamide beads and perifused. Uremic rats had higher concentrations of blood urea nitrogen, serum creatinine, and immunoreactive insulin and lower concentration of plasma 1,25-(OH)2D3 than control rats. Although the basal insulin release in the presence of 5.0 mM glucose showed no difference between uremic and control rats, the initial insulin release in the presence of 16.2 mM glucose was significantly lower (p less than 0.05) in uremic than in controls rats. The insulin content in islets was not different between both groups. These findings suggest that there might be impairment of the initial insulin secretion without changes of insulin content in pancreatic islets in uremia.

Randomized Controlled Trial of Two Forms of Self-Management Group Education in Japanese People with Impaired Glucose Tolerance

The aim of this study was to determine the effectiveness of education on diabetes prevention in subjects with impaired glucose tolerance. A total of 100 subjects of impaired glucose tolerance with hemoglobin A1c (HbA1c) levels ≥5.5 to <6.1% were assigned randomly to either support or control groups. All subjects received education in 8 sessions over a 6-month period. The support group consisted of 10 members collaborating with a dietitian or a nurse who learned coping skills by employing a participant-centered approach. Participants in the support group were required to keep a diary that monitored weight, food intake and blood glucose levels, while the control group attended several lectures. Subjects assigned to the support group had a reduction in mean HbA1c levels from 5.77 ± 0.36% at baseline to 5.39 ± 0.24% at the endpoint (p<0.01). Weight, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels also decreased (p<0.01) in the support group, whereas subjects in the control group had no observable reduction in these indices. After intervention, participants of the support group had improvements in their 2-h post-meal blood glucose levels. Support group education can be effective for improving glycemic control in participants when carried out in collaboration with educators and other team members.