Glucagon secretion and its association with glycaemic control and ketogenesis during sodium-glucose cotransporter 2 inhibition by ipragliflozin in people with type 1 diabetes: Results from the multicentre, open-label, prospective study.

AIM: Clinical trials showed the efficacy of sodium-glucose cotransporter 2 inhibitors for type 1 diabetes (T1D) by significant reductions in body weight and glycaemic variability, but elevated susceptibility to ketoacidosis via elevated glucagon secretion was a potential concern. The Suglat-AID evaluated glucagon responses and its associations with glycaemic control and ketogenesis before and after T1D treatment with the sodium-glucose cotransporter 2 inhibitor, ipragliflozin. METHODS: Adults with T1D (n = 25) took 50-mg open-labelled ipragliflozin daily as adjunctive to insulin. Laboratory/clinical data including continuous glucose monitoring were collected until 12 weeks after the ipragliflozin initiation. The participants underwent a mixed-meal tolerance test (MMTT) twice [before (first MMTT) and 12 weeks after ipragliflozin treatment (second MMTT)] to evaluate responses of glucose, C-peptide, glucagon and ß-hydroxybutyrate. RESULTS: The area under the curve from fasting (0 min) to 120 min (AUC0-120min) of glucagon in second MMTT were significantly increased by 14% versus first MMTT. The fasting and postprandial ß-hydroxybutyrate levels were significantly elevated in second MMTT versus first MMTT. The positive correlation between postprandial glucagon secretion and glucose excursions observed in first MMTT disappeared in second MMTT, but a negative correlation between fasting glucagon and time below range (glucose, <3.9 mmol/L) appeared in second MMTT. The percentage changes in glucagon levels (fasting and AUC0-120min) from baseline to 12 weeks were significantly correlated with those in ß-hydroxybutyrate levels. CONCLUSIONS: Ipragliflozin treatment for T1D increased postprandial glucagon secretion, which did not exacerbate postprandial hyperglycaemia but might protect against hypoglycaemia, leading to reduced glycaemic variability. The increased glucagon secretion might accelerate ketogenesis when adequate insulin is not supplied.

SMTP-44D Inhibits Atherosclerotic Plaque Formation in Apolipoprotein-E Null Mice Partly by Suppressing the AGEs-RAGE Axis.

SMTP-44D has been reported to have anti-oxidative and anti-inflammatory reactions, including reduced expression of receptor for advanced glycation end products (RAGE) in experimental diabetic neuropathy. Although activation of RAGE with its ligands, and advanced glycation end products (AGEs), play a crucial role in atherosclerotic cardiovascular disease, a leading cause of death in diabetic patients, it remains unclear whether SMTP-44D could inhibit experimental atherosclerosis by suppressing the AGEs-RAGE axis. In this study, we investigated the effects of SMTP-44D on atherosclerotic plaque formation and expression of AGEs in apolipoprotein-E null (Apoe-/-) mice. We further studied here whether and how SMTP-44D inhibited foam cell formation of macrophages isolated from Apoe-/- mice ex vivo. Although administration of SMTP-44D to Apoe-/- mice did not affect clinical or biochemical parameters, it significantly decreased the surface area of atherosclerotic lesions and reduced the atheromatous plaque size, macrophage infiltration, and AGEs accumulation in the aortic roots. SMTP-44D bound to immobilized RAGE and subsequently attenuated the interaction of AGEs with RAGE in vitro. Furthermore, foam cell formation evaluated by Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and gene expression of RAGE, cyclin-dependent kinase 5 (Cdk5) and CD36 in macrophages isolated from SMTP-44D-treated Apoe-/- mice were significantly decreased compared with those from saline-treated mice. Gene expression levels of RAGE and Cdk5 were highly correlated with each other, the latter of which was also positively associated with that of CD36. The present study suggests that SMTP-44D may inhibit atherosclerotic plaque formation in Apoe-/- mice partly by blocking the AGEs-RAGE-induced ox-LDL uptake into macrophages via the suppression of Cdk5-CD36 pathway.

Efficacy of a new enzyme-linked immunosorbent assay system for three islet cell autoantibodies in Japanese patients with acute-onset type 1 diabetes.

To evaluate the clinical efficacy of a new enzyme-linked immunosorbent assay (ELISA) system for simultaneously detecting three islet cell autoantibodies against glutamic acid decarboxylase (GADA), insulinoma-associated antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A) (3 Screen ICA ELISA) in Japanese patients with acute-onset type 1 diabetes (T1D). In addition, clinical factors affecting the 3 Screen ICA ELISA index were investigated. We compared the positivity values of 3 Screen ICA ELISA with that of each autoantibody alone in 97 patients with acute-onset T1D (mean age 48.7 years, 49% male) and 100 non-diabetic subjects (mean age 47.0 years, 50% male). Serum thyroid stimulating hormone receptor antibody, thyroid peroxidase antibody (TPOAb) and thyroglobulin autoantibody levels were also evaluated. The cut-off value of the 3 Screen ICA ELISA was determined based on the 97th percentile of 100 non-diabetic controls (threshold for positivity, ≥14 index). The mean age of disease onset and duration of diabetes were 34.2 years and 14.5 years, respectively. Among all T1D patients, the positivity of 3 Screen ICA ELISA was 71.1%, while that of GADA, IA-2A, and ZnT8A were 59.8%, 25.8%, and 25.8%, respectively. The median 3 Screen ICA index was 121.9 (8.7-468.2) and was associated with titers of each autoantibody, most so with GADA, and was significantly higher in TPOAb-positive patients than in TPOAb-negative patients. Our findings suggests that the 3 Screen ICA ELISA may be a time-saving diagnostic tool for evaluating islet autoantibodies in acute-onset T1D patients.

A Dipeptidyl Peptidase-4 Inhibitor Inhibits Foam Cell Formation of Macrophages in Type 1 Diabetes via Suppression of CD36 and ACAT-1 Expression.

Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to play a protective role against atherosclerosis in both animal models and patients with type 2 diabetes (T2D). However, since T2D is associated with dyslipidemia, hypertension and insulin resistance, part of which are ameliorated by DPP-4 inhibitors, it remains unclear whether DPP-4 inhibitors could have anti-atherosclerotic properties directly by attenuating the harmful effects of hyperglycemia. Therefore, we examined whether a DPP-4 inhibitor, teneligliptin, could suppress oxidized low-density lipoprotein (ox-LDL) uptake, foam cell formation, CD36 and acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) gene expression of macrophages isolated from streptozotocin-induced type 1 diabetes (T1D) mice and T1D patients as well as advanced glycation end product (AGE)-exposed mouse peritoneal macrophages and THP-1 cells. Foam cell formation, CD36 and ACAT-1 gene expression of macrophages derived from T1D mice or patients increased compared with those from non-diabetic controls, all of which were inhibited by 10 nmol/L teneligliptin. AGEs mimicked the effects of T1D; teneligliptin attenuated all the deleterious effects of AGEs in mouse macrophages and THP-1 cells. Our present findings suggest that teneligliptin may inhibit foam cell formation of macrophages in T1D via suppression of CD36 and ACAT-1 gene expression partly by attenuating the harmful effects of AGEs.

AGE-RAGE Axis Stimulates Oxidized LDL Uptake into Macrophages through Cyclin-Dependent Kinase 5-CD36 Pathway via Oxidative Stress Generation.

Advanced glycation end products (AGEs) are localized in macrophage-derived foam cells within atherosclerotic lesions, which could be associated with the increased risk of atherosclerotic cardiovascular disease under diabetic conditions. Although foam cell formation of macrophages has been shown to be enhanced by AGEs, the underlying molecular mechanism remains unclear. Since cyclin-dependent kinase 5 (Cdk5) is reported to modulate inflammatory responses in macrophages, we investigated whether Cdk5 could be involved in AGE-induced CD36 gene expression and foam cell formation of macrophages. AGEs significantly increased Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and Cdk5 and CD36 gene expression in U937 human macrophages, all of which were inhibited by DNA aptamer raised against RAGE (RAGE-aptamer). Cdk5 and CD36 gene expression levels were correlated with each other. An antioxidant, N-acetyl-l-cysteine, mimicked the effects of RAGE-aptamer on AGE-exposed U937 cells. A selective inhibitor of Cdk5, (R)-DRF053, attenuated the AGE-induced Dil-ox-LDL uptake and CD36 gene expression, whereas anti-CD36 antibody inhibited the Dil-ox-LDL uptake but not Cdk5 gene expression. The present study suggests that AGEs may stimulate ox-LDL uptake into macrophages through the Cdk5-CD36 pathway via RAGE-mediated oxidative stress.

Antiatherogenic effects of liraglutide in hyperglycemic apolipoprotein E-null mice via AMP-activated protein kinase-independent mechanisms.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert potent glucose-lowering effects without increasing risks for hypoglycemia and weight gain. Preclinical studies have demonstrated direct antiatherogenic effects of GLP-1RAs in normoglycemic animal models; however, the underlying mechanisms in hyperglycemic conditions have not been fully clarified. Here we aimed to elucidate the role of AMP-activated protein kinase (AMPK) in antiatherogenic effects of GLP-1RAs in hyperglycemic mice. Streptozotocin-induced hyperglycemic apolipoprotein E-null mice were treated with vehicle, low-dose liraglutide (17 nmol·kg-1·day-1), or high-dose liraglutide (107 nmol·kg-1·day-1) in experiment 1 and the AMPK inhibitor dorsomorphin, dorsomorphin + low-dose liraglutide, or dorsomorphin + high-dose liraglutide in experiment 2. Four weeks after treatment, aortas were collected to assess atherosclerosis. In experiment 1, metabolic parameters were similar among the groups. Assessment of atherosclerosis revealed that high-dose liraglutide treatments reduced lipid deposition on the aortic surface and plaque volume and intraplaque macrophage accumulation at the aortic sinus. In experiment 2, liraglutide-induced AMPK phosphorylation in the aorta was abolished by dorsomorphin; however, the antiatherogenic effects of high-dose liraglutide were preserved. In cultured human umbilical vein endothelial cells, liraglutide suppressed tumor necrosis factor-induced expression of proatherogenic molecules; these effects were maintained under small interfering RNA-mediated knockdown of AMPKα1 and in the presence of dorsomorphin. Conversely, in human monocytic U937 cells, the anti-inflammatory effects of liraglutide were abolished by dorsomorphin. In conclusion, liraglutide exerted AMPK-independent antiatherogenic effects in hyperlipidemic mice with streptozotocin-induced hyperglycemia, with the possible involvement of AMPK-independent suppression of proatherogenic molecules in vascular endothelial cells.

Luseogliflozin attenuates neointimal hyperplasia after wire injury in high-fat diet-fed mice via inhibition of perivascular adipose tissue remodeling.

BACKGROUND: Excess fat deposition could induce phenotypic changes of perivascular adipose tissue (PVAT remodeling), which may promote the progression of atherosclerosis via modulation of adipocytokine secretion. However, it remains unclear whether and how suppression of PVAT remodeling could attenuate vascular injury. In this study, we examined the effect of sodium-glucose cotransporter 2 (SGLT2) inhibitor, luseogliflozin on PVAT remodeling and neointima formation after wire injury in mice. METHODS: Wilt-type mice fed with low-fat diet (LFD) or high-fat diet (HFD) received oral administration of luseogliflozin (18 mg/kg/day) or vehicle. Mice underwent bilateral femoral artery wire injury followed by unilateral removal of surrounding PVAT. After 25 days, injured femoral arteries and surrounding PVAT were analyzed. RESULTS: In LFD-fed lean mice, neither luseogliflozin treatment or PVAT removal attenuated the intima-to-media (I/M) ratio of injured arteries. However, in HFD-fed mice, luseogliflozin or PVAT removal reduced the I/M ratio, whereas their combination showed no additive reduction. In PVAT surrounding injured femoral arteries of HFD-fed mice, luseogliflozin treatment decreased the adipocyte sizes. Furthermore, luseogliflozin reduced accumulation of macrophages expressing platelet-derived growth factor-B (PDGF-B) and increased adiponectin gene expression. Gene expression levels of Pdgf-b in PVAT were correlated with the I/M ratio. CONCLUSIONS: Our present study suggests that luseogliflozin could attenuate neointimal hyperplasia after wire injury in HFD-fed mice partly via suppression of macrophage PDGF-B expression in PVAT. Inhibition of PVAT remodeling by luseogliflozin may be a novel therapeutic target for vascular remodeling after angioplasty.

[Bone fragility in type 1 diabetes and type 2 diabetes.]

Diabetes mellitus causes hyperglycemia due to resistance to insulin action in peripheral organs in addition to progressive loss of ß-cell function, thus it is involved in the development and progression of diabetic microangiopathy(retinopathy, nephropathy, and neuropathy). In addition, abnormalities of bone metabolism is regarded as a chronic complication related to both type 1 diabetes and type 2 diabetes. Accumulating evidence suggests that type 1 diabetes patients had decreased bone mineral density(BMD)and the fracture risk in the femoral neck is markedly higher, when compared to non-diabetic patients. A lack of insulin level in the portal vein is associated with systemic deficiencies of Insulin-like growth factor-1(IGF-1), known as growth-promoting polypeptide essential for promoting growth and bone formation. Thus, loss of IGF-1 play a crucial role for the pathogenesis of reduced BMD in type 1 diabetes. In type 2 diabetes, despite high bone mineral density with obesity, several studies have shown that men and women with type 2 diabetes mellitus are at increased risk for bone fracture. In other words, unlike type 1 diabetes patients, an increase in the risk of fracture in type 2 diabetes is significantly related to compromised bone quality, the other factor of impaired bone strength.

Crucial role of Reg I from acinar-like cell cluster touching with islets (ATLANTIS) on mitogenesis of beta cells in EMC virus-induced diabetic mice.

Recently, we reported the presence of distinct cell clusters named acinar-like cell clusters touching Langerhans islets with thin interstitial surrounding (ATLANTIS) in human pancreas. A morphological study in humans demonstrated that ATLANTIS and islet cell clusters are found together in the microenvironment enclosed by a common basement membrane, and ATLANTIS releases vesicles containing Regenerating gene protein (REG Iα) to islet cell clusters. We examined 1) the presence or absence of ATLANTIS in homozygous Reg I (mouse homologue of human REG Iα) deficient (Reg I-/-) and wild-type mice, and 2) the possible role of ATLANTIS in the regeneration of beta cell clusters after encephalomyocarditis (EMC) virus (D-variant) infection in Reg I-/- and wild-type mice. ATLANTIS was found in both wild-type and Reg I-/- mice. In both groups, mean blood glucose increased transiently to greater than 14.0 mmol/L at 5 days after EMC virus infection and recovered to baseline at 12 days. At 12 days after EMC virus infection, lower BrdU labeling indices were observed in islet beta cells of Reg I-/- mice compared to wild-type mice. Beta cell volume 12 days after EMC virus infection in Reg I-/- mice did not differ from that of wild-type mice. These results suggest that Reg I, which is released from ATLANTIS to islet beta cell clusters, has a crucial role in beta cell regeneration in EMC virus-induced diabetes. The presence of mechanism(s) other than that mediated by Reg I in beta cell restoration after destruction by EMC virus was also suggested.

Quadrant Analysis of Quantitative Computed Tomography Scans of the Femoral Neck Reveals Superior Region-Specific Weakness in Young and Middle-Aged Men With Type 1 Diabetes Mellitus.

We have previously shown that the intertrochanter of young and middle-aged patients with type 1 diabetes mellitus (T1DM) showed higher buckling ratio (an index of cortical instability) and lower volumetric bone mineral density (vBMD). However, we have not yet reported the detailed findings regarding the mechanical and density properties of the femoral neck. Therefore, we present a subanalysis of our previous study with the aim of further evaluating the middle third of the femoral neck via quadrant quantitative computed tomography in young and middle-aged patients with T1DM. Bone parameters in 4 anatomical quadrants (superoanterior [SA], inferoanterior [IA], inferoposterior [IP], and superoposterior [SP]) were cross-sectionally evaluated in 17 male T1DM patients and 18 sex-matched healthy controls aged between 18 and 49 yr using quadrant quantitative computed tomography analysis. Patients with T1DM had a thinner cortical thickness in the SP quadrant and a significantly lower cortical vBMD in the SA quadrant than the controls. The serum insulin-like growth factor-1 values in patients with T1DM were positively correlated with the average cortical thickness in the SA quadrant and the average trabecular vBMD in the SP quadrant of the femoral neck. The cortical thickness in controls was negatively correlated with age in the SP and IP quadrants. The cortical thickness in patients with T1DM showed no correlation with age in all quadrants. The fragility of the femoral neck was remarkable in the superior region of patients with T1DM. Insulin-like growth factor-1 may play an important role in superior cortical thinning and in lowering cortical vBMD. Furthermore, in young and middle-aged men with T1DM, the structure of the femoral neck exhibits similar changes as those observed with aging.

The role of endothelial nitric oxide in the anti-restenotic effects of liraglutide in a mouse model of restenosis.

BACKGROUND: Previous animal studies have shown that glucagon-like peptide-1 receptor agonists (GLP-1RAs) suppress arterial restenosis, a major complication of angioplasty, presumably through their direct action on vascular smooth muscle cells. However, the contribution of vascular endothelial cells (VECs) to this process remains unknown. In addition, the potential interference caused by severe hyperglycemia and optimal treatment regimen remain to be determined. METHODS: Nine-week-old male C57BL6 (wild-type) and diabetic db/db mice were randomly divided into vehicle or liraglutide treatment groups (Day 1), and subject to femoral artery wire injuries (Day 3). The injured arteries were collected on Day 29 for morphometric analysis. Human umbilical vein endothelial cells (HUVECs) were used for in vitro experiments. One-way ANOVA, followed by Tukey's test, was used for comparisons. RESULTS: In wild-type mice, liraglutide treatment (5.7, 17, or 107 nmol/kg/day) dose-dependently reduced the neointimal area (20, 50, and 65%) without inducing systemic effects, and caused an associated decrease in the percentage of vascular proliferating cells. However, these effects were completely abolished by the nitric oxide synthase (NOS) inhibitor N-omega-nitro-L-arginine methyl ester. Next, we investigated the optimal treatment regimen. Early treatment (Days 1-14) was as effective in reducing the neointimal area and vascular cell proliferation as full treatment (Days 1-29), whereas delayed treatment (Days 15-29) was ineffective. In HUVECs, liraglutide treatment dose-dependently stimulated NO production, which was dependent on GLP-1R, cAMP, cAMP-dependent protein kinase, AMP-activated protein kinase (AMPK), and NOS. Subsequently, we investigated the role of liver kinase B (LKB)-1 in this process. Liraglutide increased the phosphorylation of LKB-1, and siRNA-induced LKB-1 knockdown abolished liraglutide-stimulated NO production. In severe hyperglycemic db/db mice, liraglutide treatment also suppressed neointimal hyperplasia, which was accompanied by reductions in vascular cell proliferation and density. Furthermore, liraglutide treatment suppressed hyperglycemia-enhanced vascular inflammation 7 days after arterial injury. CONCLUSIONS: We demonstrate that endothelial cells are targets of liraglutide, and suppress restenosis via endothelial NO. Furthermore, the protective effects are maintained in severe hyperglycemia. Our findings provide an evidence base for a future clinical trial to determine whether treatment with GLP-1RAs represents potentially effective pharmacological therapy following angioplasty in patients with diabetes.

Dapagliflozin decreases small dense low-density lipoprotein-cholesterol and increases high-density lipoprotein 2-cholesterol in patients with type 2 diabetes: comparison with sitagliptin.

BACKGROUND: The sodium-glucose co-transporter-2 (SGLT-2) inhibitors have been reported to increase both low-density lipoprotein (LDL) and high-density lipoprotein (HDL)-cholesterol (C). This study aimed to determine how SGLT-2 inhibitors affect LDL and HDL-C subspecies. METHODS: This single center, open-label, randomized, prospective study included 80 patients with type 2 diabetes taking prescribed oral hypoglycemic agents. Patients were allocated to receive dapagliflozin (n = 40) or sitagliptin (n = 40) as add-on treatment. Fasting blood samples were collected before and 12 weeks after this intervention. Small dense (sd) LDL-C, large buoyant (lb) LDL-C, HDL2-C, and HDL3-C levels were determined using our established homogeneous assays. Statistical comparison of blood parameters before and after treatment was performed using the paired t test. RESULTS: Dapagliflozin and sitagliptin comparably decreased HbA1c (0.75 and 0.63%, respectively). Dapagliflozin significantly decreased body weight, systolic blood pressure, plasma triglycerides and liver transaminases, and increased adiponectin; sitagliptin did not alter these measurements. LDL-C and apolipoprotein (apo) B were not significantly changed by dapagliflozin, whereas HDL-C and apo AI were increased. Dapagliflozin did not alter concentrations of LDL-C, but sd LDL-C decreased by 20% and lb LDL-C increased by 18%. Marked elevation in lb LDL-C (53%) was observed in individuals (n = 20) whose LDL-C was elevated by dapagliflozin. However, sd LDL-C remained suppressed (20%). Dapagliflozin increased HDL2-C by 18% without affecting HDL3-C. Sitagliptin did not alter plasma lipids or lipoprotein subspecies. CONCLUSIONS: A SGLT-2 inhibitor, dapagliflozin suppresses potent atherogenic sd LDL-C and increased HDL2-C, a favorable cardiometabolic marker. Although LDL-C levels are elevated by treatment with dapagliflozin, this was due to increased concentrations of the less atherogenic lb LDL-C. However, these findings were not observed after treatment with dipeptidyl peptidase-4 inhibitor, sitagliptin. Trial registration UMIN Clinical Trials Registry (UMIN000020984).

Correction to: Dapagliflozin decreases small dense low-density lipoprotein-cholesterol and increases high-density lipoprotein 2-cholesterol in patients with type 2 diabetes: comparison with sitagliptin.

Following publication of the original article [1], the authors identified a number of errors. In Result (P.3), Table 1 (P.4), Table 5 (P.9) and Supplementary Table 1, the correct unit for adiponectin was µg/mL. In Table 1 (P.4), the correct value for the post treatment body weight in dapagliflozin was 76.2±14.8. In Table 6 (P.10), the correct value for the pre treatment sd LDL/LDL-C in decreased LDL-C group was 0.38±0.10.

Comparison of Effects of Injectable Semaglutide and Dulaglutide on Oxidative Stress and Glucose Variability in Patients with Type 2 Diabetes Mellitus: A Prospective Preliminary Study.

INTRODUCTION: Recent trials have shown that glucagon-like peptide-1 receptor agonists considerably reduce atherosclerotic cardiovascular disease in patients with type 2 diabetes mellitus (T2DM). Oxidative stress, a surrogate marker of cardiovascular risk, is associated with glucose variability. However, to the best of our knowledge, no studies have compared the effects of injectable semaglutide and dulaglutide therapies on oxidative stress and glucose variability assessed via continuous glucose monitoring (CGM). This study aimed to analyze and compare the effects of semaglutide and dulaglutide therapies on oxidative stress and glucose variability as assessed through CGM. METHODS: This is an open-label, multicenter, randomized, prospective, parallel-group comparison study. Overall, 37 patients with T2DM treated with dulaglutide for at least 12 weeks were randomized into two groups: one receiving continuous dulaglutide therapy (n = 19) and one receiving injectable semaglutide therapy (n = 18) groups. The coprimary endpoints were changes in the results of the diacron-reactive oxygen metabolites test, an oxidative stress marker, and CGM-evaluated glucose variability after 24 weeks. The secondary endpoint was changes in the Diabetes Treatment Satisfaction Questionnaire (DTSQ) scores. RESULTS: Switching to semaglutide therapy was better than continuous dulaglutide therapy in reducing oxidative stress, glucose variability, and glycated hemoglobin levels. Conversely, continuous dulaglutide therapy was better than semaglutide therapy in terms of DTSQ scores for "Convenience" and "Recommend." CONCLUSION: Injectable semaglutide therapy may be more effective than dulaglutide therapy in ameliorating oxidative stress and regulating glucose metabolism, including glucose variability, in patients with T2DM, while dulaglutide therapy may be more effective in terms of treatment satisfaction. CLINICAL TRIAL REGISTRATION: UMIN-CRT ID: UMIN000042670 (registered 7 December 2020).

New diagnostic criteria (2023) for slowly progressive type 1 diabetes (SPIDDM): Report from Committee on Type 1 Diabetes of the Japan Diabetes Society (English version).

The diagnostic criteria for slowly progressive type 1 diabetes (slowly progressive insulin-dependent diabetes mellitus; SPIDDM) have been revised by the Committee on Type 1 Diabetes of the Japan Diabetes Society. All of the following three criteria must be met for 'a definitive diagnosis of SPIDDM': (1) presence of anti-islet autoantibodies at some point in time during the disease course; (2) absence of ketosis or ketoacidosis at the diagnosis of diabetes with no requirement for insulin treatment to correct hyperglycemia immediately after diagnosis in principle; and (3) gradual decrease of insulin secretion over time, with insulin treatment required at more than 3 months after diagnosis, and the presence of severe endogenous insulin deficiency (fasting serum C-peptide immunoreactivity <0.6 ng/mL) at the last observed point in time. When a patient fulfills only (1) and (2), but not (3), he/she is diagnosed with 'SPIDDM (probable)' because the diabetes is non-insulin-dependent type.

New diagnostic criteria (2023) for slowly progressive type 1 diabetes (SPIDDM): Report from Committee on Type 1 Diabetes in Japan Diabetes Society (English version).

The diagnostic criteria for slowly progressive type 1 diabetes (slowly progressive insulin-dependent diabetes mellitus; SPIDDM) have been revised by the Committee on Type 1 Diabetes of the Japan Diabetes Society. All of the following three criteria must be met for "a definitive diagnosis of SPIDDM": (1) presence of anti-islet autoantibodies at some point in time during the disease course; (2) absence of ketosis or ketoacidosis at the diagnosis of diabetes with no requirement of insulin treatment to correct hyperglycemia immediately after diagnosis in principle; and (3) gradual decrease of insulin secretion over time, with insulin treatment required at more than 3 months after diagnosis, and presence of severe endogenous insulin deficiency (fasting serum C-peptide immunoreactivity < 0.6 ng/mL) at the last observed point in time. When a patient fulfills the only (1) and (2), but not (3), he/she is diagnosed with "SPIDDM (probable)" because the diabetes is non-insulin-dependent state.

Correction: New diagnostic criteria (2023) for slowly progressive type 1 diabetes (SPIDDM): Report from Committee on Type 1 Diabetes in Japan Diabetes Society (English version).

[This corrects the article DOI: 10.1007/s13340-023-00679-1.].

Prediction of future insulin-deficiency in glutamic acid decarboxylase autoantibody enzyme-linked immunosorbent assay-positive patients with slowly-progressive type 1 diabetes.

AIMS/INTRODUCTION: This study aimed to identify risk factors that contribute to the progression of slowly-progressive type 1 diabetes by evaluating the positive predictive value (PPV) of factors associated with the progression to an insulin-dependent state. MATERIALS AND METHODS: We selected 60 slowly-progressive type 1 diabetes patients who tested positive for glutamic acid decarboxylase autoantibodies (GADA) at diagnosis from the Japanese Type 1 Diabetes Database Study. GADA levels in these patients were concurrently measured using both radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques. RESULTS: Compared with the non-progressor group (fasting C-peptide [F-CPR] levels maintained ≥0.6 ng/mL), the progressor group showed a younger age at diagnosis, lower body mass index (BMI), lower F-CPR levels and a higher prevalence of insulinoma-associated antigen-2 autoantibodies (IA-2A). The PPV of RIA-GADA increased from 56.3 to 70.0% in the high titer group (≥10 U/mL), and further increased to 76.9, 84.2, 81.0 and 75.0% when combined with specific thresholds for age at diagnosis <47 years, BMI <22.6 kg/m2, F-CPR <1.41 ng/mL and IA-2A positivity, respectively. In contrast, the PPV of ELISA-GADA (71.8%) remained the same at 73.1% in the high titer group (≥180 U/mL), but increased to 81.8, 82.4 and 79.0% when evaluated in conjunction with age at diagnosis, BMI and F-CPR level, respectively. CONCLUSIONS: Our findings show that, unlike RIA-GADA, ELISA-GADA shows no association between GADA titers and the risk of progression to an insulin-dependent state. The PPV improves when age at diagnosis, BMI and F-CPR levels are considered in combination.

Increment of C-peptide after glucagon injection determines the progressive nature of Japanese type 2 diabetes: a long-term follow-up study.

Type 2 diabetes (T2D) is characterized by a steady worsening of ß-cell dysfunction as the disease progresses. The objective of this study was to estimate the decline of insulin secretion in Japanese type 2 diabetic patients (T2D-patients) by glucagon injection over an observation period of more than 10 years. Thirty-three T2D-patients were followed for 10.4 ± 1.4 years. Fasting C-peptide immunoreactivity (FCPR), the 6 min value of CPR after glucagon injection (6MCPR), and the increment of CPR (ΔCPR) were measured at baseline and follow-up. FCPR, 6MCPR, ΔCPR were significantly lower at follow-up than at baseline (p<0.05, p<0.005, and p<0.0005, respectively). The annual change of ΔCPR was significantly (p<0.05) greater than the annual change of FCPR (-0.062 ± 0.076 ng/mL/year and -0.025 ± 0.067 ng/mL/year, respectively). In contrast, CPR-index (an index of ß-cell function) and SUIT-index (secretory units of islets in transplantation) calculated based on fasting blood samples were unaltered. The annual changes of FCPR, 6MCPR, and ΔCPR were negatively correlated with the FCPR, 6MCPR, and ΔCPR values at baseline, respectively. Duration of diabetes, BMI, diabetic retinopathy, and secondary sulfonylurea failure at baseline were not correlated with the annual changes of FCPR, 6MCPR, and ΔCPR. In conclusion, our longitudinal observations suggest that ß-cell function progressively declines in Japanese T2D-patients. The annual declines of ΔCPR were more prominent than the annual declines of FCPR. ΔCPR after glucagon injection may be more useful for estimating individual longitudinal insulin secretion than fasting blood samples.