Onset of type 2 diabetes (T2D) is based on the insulin secretion (loss of β-cell function) and resistance. Residual β-cell function is a key factor in achieving optimal glycemic control in T2D patients. Glucagon stimulates insulin, therefore glucagon stimulation test (GST) is a reliable marker for β-cell function. Fasting C-peptide (CPR) to glucose ratio (CPR[ng/ml] to glucose[mg/dl] x100; F-CPR-index) is used as a marker of insulin secretion. We evaluated the efficacy of postprandial CPR to glucose ratio (P-CPR-index) for evaluating β-cell function in T2D. Japanese T2D patients with inadequate glycemic control (HbA1c>7.0) were enrolled in the study (n=500, insulin therapy=283). HbA1c, fasting CPR and glucose, postprandial (120 min after breakfast) CPR and glucose were measured, and F-CPR-index and P-CPR-index were calculated. GST was performed as follows: 1mg of glucagon was injected intravenously, CPR was determined before and 6 min after injection, GSTΔCPR (CPR[6 min] - CPR[0 min]) was calculated. Factors correlated with GSTΔCPR were analyzed using simple and multiple stepwise regression analysis. P value<0.05 was defined as statistically different. F-CPR-index, P-CPR-index and GSTΔCPR were 1.60±0.95, 2.67±1.92 and 1.93±1.21, respectively. Simple regression analysis showed that GSTΔCPR was significantly correlated with age, height, body weight (BW), BMI, waist circumference, duration of diabetes, retinopathy, insulin therapy, urinary CPR, F-CPR-index and P-CPR-index. Multiple stepwise regression analysis revealed that independent factors contributing to GSTΔCPR were BW (β=0.336), duration of diabetes (β= −0.107), presence of retinopathy (β= −0.121), use of DPP-4i (β= −0.099), metformin (β= −0.109), SGLT2i (β= −0.108, p=0.002) and P-CPR-index (β=0.432)(R2=0.453). Our date demonstrated that P-CPR-index was valuable and simple method in assessing residual β-cell function with/without insulin therapy in daily clinical practice. Disclosure Y.Matsuhashi: None. T.Abe: None. T.Fujita: None. S.Mizushiri: None. S.Chikazawa: None. M.Daimon: None.
Background: Diabetic dyslipidemia is characterized by elevated levels of triglyceride-rich lipoproteins and reduced levels of HDL-cholesterol (HDL-C) . Low levels of HDL-C are associated with an increased risk of atherosclerotic cardiovascular disease, because HDL protects against atherosclerosis through multiple mechanisms include removal of excess cholesterol from macrophages. HDL can also influence cholesterol homeostasis in pancreatic β-cell. It is noteworthy that absence of ATP-binding cassette transporter A1 (ABCA1) , which is a cellular cholesterol transporter and regulates islet cholesterol efflux, results in islet cholesterol overload and impaired insulin release in mice. We examined the associations of cholesterol efflux and insulin secretion in MIN6 cells with polyphenols that is reported to increase cholesterol efflux. Methods: Murine MIN6 cells were labeled with 3H-cholesterol and incubated with ApoA1 (μg/ml) or HDL (25 μg/ml) for 24 hours. The percentage cholesterol efflux was calculated by dividing the media-derived radioactivity by the sum of the radioactivity in the media and the cells. The effect of polyphenols on the cholesterol efflux was studied, adding that into the medium before the analysis of the cholesterol efflux. Insulin secretion was assessed by ELISA as the concentration of insulin in the culture medium. The mRNA expression of ABCA1 and ABCG1 were determined by real-time Quantitative RT-PCR. Results: Under the existence of polyphenols (isorhamnetin) , the ApoA1 or HDL-mediated cholesterol efflux had significantly increased by 1.4% or 1.8%, respectively (n=4, p<0.01) . Isorhamnetin had increased insulin secretion by 882 ng/mg protein/h (n=3, p<0.05) and significantly decreased ABCA1 and ABCG1 expressions. Conclusion: These data suggest that isorhamnetin increases cholesterol efflux and insulin secretion in MIN6 cells. Isorhamnetin could be the interesting candidate to investigate the new treatment for patients with diabetes mellitus. Disclosure K.Matsuki: None. Y.Kimura: None. K.Matsumura: None. J.Tanabe: None. H.Murakami: None. M.Daimon: None. Funding JSPS KAKENHI Grant Number 20K11549
Inflammation, insulin resistance (IR) , and deficit of retrograde axonal transport (RAT) are implicated in the pathogenesis of diabetic polyneuropathy (DPN) . Pro-inflammatory macrophage (M1) skewed by diabetic insults causes IR in adipose tissue. The activation of Advanced Glycation End products (AGEs) - Receptor for AGEs (RAGE) signaling is involved in the macrophage polarization into M1, while its contribution to the deficit of RAT in DPN is still unclear. In this study, we investigated the implication of M1-related inflammation to RAT deficit in sensory neurons. We evaluated the activation of macrophage cell line RAW 264.7 (RAW) and neurons isolated from dorsal root ganglia (DRG) of C57BL/6 mice stimulated by 200 μg/ml of AGE. A DRG neurons-RAW co-culture system was established by seeding RAW onto DRG neurons. After 12h co-culturing, we added AGE to the co-culture and stimulated RAW. A DRG neuronal mono-culture was treated with 500 nM of insulin receptor antagonist (BMS-754807) , and 20 ng/ml of TNF-α with/without 50 nM JNK inhibitor (SP600125) . Axonal transport was visualized by Lysotracker and captured by time-lapse microscopy. The movements were quantified on kymographs generated from 100 μm axonal segments. AGE induced the M1 phenotype in RAW with elevated expressions of iNOS and TNF-α mRNA, while no effects on DRG neuron were identified. In the co-culture, the frequency of RAT (RAT%) was significantly reduced when RAW was stimulated by AGE compared to naive RAW (p < 0.001) . In the mono-culture, RAT% was significantly reduced when neurons were treated with BMS-7548 and TNFα (vs. control, both p < 0.001) . TNFα stimulation also increased the phosphorylation of JNK in the axons, a major target of TNFα, which was confirmed by immunofluorescence. The reduction of RAT% by TNFα was rescued by SP600125. In summary, RAT could be impaired by TNF-α and IR, which suggests inflammation induced by M1 in SN can attenuate RAT, which contributes to the DPN pathology. Disclosure S.Osonoi: None. H.Mizukami: None. S.Ogasawara: None. K.Kudoh: None. M.Daimon: None. S.Yagihashi: None. Funding Japan Society for the Promotion of Science (18K16220)
Objective: Equol (Eq) , a metabolite produced from soy isoflavone daidzein by intestinal bacteria, exhibits estrogen activity and may exert effects on glucose metabolism. Eq levels vary extensively depending on the capability for Eq production and amounts of daidzein consumed. We examined the relationship between Eq levels and type 2 diabetes mellitus. Research Design and Methods: Among 1,395 outpatients with diabetes at our hospital, 147 subjects (age: 70-89 years) were recruited (DM group) . Also, 147 age-/sex-matched non-DM subjects were recruited from 1,113 individuals who underwent routine health examinations (non-DM group) . As the estrogenic effect of Eq becomes apparent after menopause, the subjects were age restricted. Eq producers (EqPr) were determined based on the logarithm of the ratio of urinary Eq to the concentration of daidzein with a cut-off value of −1.75. Results: Urinary daidzein (p=0.03) and Eq concentrations (p=0.01) were significantly lower in the DM group versus the non-DM group. The proportion of EqPr differed significantly between the groups (38.8% and 53.1%, respectively; p=0.01) . However, analyses with sex-based stratification showed such difference only in women; the proportion of EqPr was 31.4% and 52.8%, respectively (p<0.01) . Reversely, there were significantly fewer DM subjects among EqPr versus non-EqPr (p=0.01) . Among women, EqPr had significantly less DM than non-EqPr (p<0.01) . However, such differences were not observed in men. Correlation analyses showed a significant positive correlation between urinary Eq and daidzein concentrations only in EqPr (r=0.55, p<0.01) . Conclusion: In postmenopausal women, EqPr were less diabetic; this status appears to be protective against DM. Eq levels increased in parallel with the amount of daidzein consumed in EqPr, but not in non-EqPr. Therefore, Eq supplements and/or enteric bacteria transplantation, rather than dietary intervention, may be effective in preventing DM in non-EqPr. Disclosure K.Hamaura: None. H.Murakami: None. A.Tamura: None. Y.Nishiya: None. S.Mizushiri: None. M.Daimon: None.
Since type 2 diabetes (T2D) is a heterogenous disease, treatment of T2D appears to be better personalized depending on their underlining conditions. A recent attempt to classify adult-onset DM based on only 6 DM related variables (GAD antibodies, age at diagnosis, BMI, HbA1c, and HOMA2 indices) , showed that DM can be classified into 5 clusters, among them 4 represent T2D (Lancet Diabetes Endocrinol. 2018;6:361) . We here classified non-diabetic population to find risk cluster for incident DM, or to extend strategies for prevention of T2D. The participants were recruited from Iwaki study, a health promotion study of Japanese people. Among 1167 participants in 2014 (baseline) , 868 non-diabetic individuals who attended at least one time in 2015 to 20were included in this prospective study. A hierarchical cluster analysis was performed based on 5 variables (age, BMI, HbA1c, HOMA2-β, and HOMA2-IR) . The hazard ratios (HRs) for incident T2D of clusters observed were examined using Cox proportional hazards model. Traits (mean) of 5 clusters observed were as follows: age (clusters; 1: 60.1, 2: 58.7, 3: 63.6, 4: 36.1, 5: 48.3) , BMI (1: 20.8, 2: 24.2, 3: 22.9, 4: 20.7, 5: 27.7) , HbA1c (1: 5.54, 2: 5.67, 3: 6.01, 4: 5.41, 5: 5.73) , HOMA2-β (1: 82.8, 2: 101.8, 3: 78.5, 4: 101.4, 5: 143.1) , and HOMA2-IR (1: 0.53, 2: 0.79, 3: 0.73, 4: 0.57, 5: 1.16) . The HR for incident T2D was significantly higher in cluster 3 than in clusters 1, 2, and 4, even after adjustment for age and sex (HR (p) : 5.00 (0.005) , 4.90 (0.005) , and 10.4 (0.048) , respectively) . Accordingly, cluster 3 had significantly higher age and HbA1c than other clusters, lower HOMA2-β than clusters 2, 4, and 5, and lower HOMA2-IR and BMI than clusters 2 and 5. In summary, cluster analysis of a general non-diabetic population revealed a risk cluster for incident T2D, and, thus, individuals with characteristics representing the cluster (less insulin resistant but decreased insulin secretion, older age, and poor metabolic control) should be a target for prevention of incident T2D. Disclosure R.Ito: None. M.Daimon: None. S.Mizushiri: None. S.Ono: None. Y.Nishiya: None. A.Tamura: None. M.Murabayashi: None. A.Kamba: None.
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