Immediate Impact of Switching from Dipeptidyl Peptidase 4 (DPP4) Inhibitors to Low-Dose (0.3 mg) Liraglutide on Glucose Profiles: A Retrospective Observational Study.

INTRODUCTION: As treatment agents for diabetes, liraglutide is a long-acting glucagon-like peptide 1 receptor agonist, and dipeptidyl peptidase 4 (DPP4) inhibitors are widely used because of their safety and tolerability. Regular treatment with liraglutide has been reported to significantly reduce blood glucose levels, but the impact of low-dose (0.3 mg) liraglutide on blood glucose levels immediately after treatment switching from a DPP4 inhibitor remains unknown. METHODS: We conducted a single-arm, retrospective, observational study in 55 inpatients with type 2 diabetes (T2D) to investigate the changes (Δ) in their blood glucose levels at six time points (6-point) from the day before (day -1) to the day after (day 1) by switching the antidiabetic treatment from a DPP4 inhibitor to liraglutide 0.3 mg (low-dose liraglutide) once daily. We also attempted to identify factors associated with the blood glucose-lowering effects of liraglutide. RESULTS: The median values of the changes in fasting, preprandial, and postprandial blood glucose levels and the fluctuations in the blood glucose levels expressed as the standard deviation of the 6-point blood glucose levels were significantly lower on day 1 than on day -1 (P < 0.05, P < 0.0001, P < 0.0001, P < 0.01, respectively); there were no cases of severe hypoglycemia. The Δ blood glucose levels were not associated with the baseline serum hemoglobin A1c values or with any markers of the insulin secreting capacity. There were no associations between the previously used blood glucose-lowering drug and the Δ blood glucose levels. CONCLUSION: Switching from a DPP4 inhibitor to low-dose (0.3 mg) liraglutide once daily significantly reduced the blood glucose levels and excursions of the blood glucose levels even from the very day after the treatment switch, with no serious adverse events.

Encapsulated human islets in alginate fiber maintain long-term functionality.

Maintenance of islet function after in vitro culture is crucial for both transplantation and research. Here we evaluated the effects of encapsulation in alginate fiber on the function of human islets which were distributed by the Alberta Islet Distribution Program. Encapsulated human islets from 15 deceased donors were cultured under 5.5 or 25 mM glucose conditions in vitro. The amounts of C-peptide and glucagon secreted from encapsulated islets into the culture media were measured periodically, and immunohistochemical studies were performed. Encapsulated islets maintained C-peptide and glucagon secretion for more than 75 days in 5 cases; in two cases, their secretion was also successfully detected even on day 180. α- and ß-cell composition and ß-cell survival in islets were unaltered in the fiber after 75 or 180 days of culture. The encapsulated islets cultured with 5.5 mM glucose, but not those with 25 mM glucose, exhibited glucose responsiveness of C-peptide secretion until day 180. We demonstrate that alginate encapsulation enabled human islets to maintain their viability and glucose responsiveness of C-peptide secretion after long-term in vitro culture, potentially for more than for 180 days.

Transcriptome and secretome profiling of sensory neurons reveals sex differences in pathways relevant to insulin sensing and insulin secretion.

Sensory neurons in the dorsal root ganglia (DRG) convey somatosensory and metabolic cues to the central nervous system and release substances from stimulated terminal endings in peripheral organs. Sex-biased variations driven by the sex chromosome complement (XX and XY) have been implicated in the sensory-islet crosstalk. However, the molecular underpinnings of these male-female differences are not known. Here, we aim to characterize the molecular repertoire and the secretome profile of the lower thoracic spinal sensory neurons and to identify molecules with sex-biased insulin sensing- and/or insulin secretion-modulating activity that are encoded independently of circulating gonadal sex hormones. We used transcriptomics and proteomics to uncover differentially expressed genes and secreted molecules in lower thoracic T5-12 DRG sensory neurons derived from sexually immature 3-week-old male and female C57BL/6J mice. Comparative transcriptome and proteome analyses revealed differential gene expression and protein secretion in DRG neurons in males and females. The transcriptome analysis identified, among others, higher insulin signaling/sensing capabilities in female DRG neurons; secretome screening uncovered several sex-specific candidate molecules with potential regulatory functions in pancreatic ß cells. Together, these data suggest a putative role of sensory interoception of insulin in the DRG-islet crosstalk with implications in sensory feedback loops in the regulation of ß-cell activity in a sex-biased manner. Finally, we provide a valuable resource of molecular and secretory targets that can be leveraged for understanding insulin interoception and insulin secretion and inform the development of novel studies/approaches to fathom the role of the sensory-islet axis in the regulation of energy balance in males and females.

Protective Effects of Imeglimin and Metformin Combination Therapy on ß-Cells in db/db Male Mice.

Imeglimin and metformin act in metabolic organs, including ß-cells, via different mechanisms. In the present study, we investigated the impacts of imeglimin, metformin, or their combination (Imeg + Met) on ß-cells, the liver, and adipose tissues in db/db mice. Imeglimin, metformin, or Imeg + Met treatment had no significant effects on glucose tolerance, insulin sensitivity, respiratory exchange ratio, or locomotor activity in db/db mice. The responsiveness of insulin secretion to glucose was recovered by Imeg + Met treatment. Furthermore, Imeg + Met treatment increased ß-cell mass by enhancing ß-cell proliferation and ameliorating ß-cell apoptosis in db/db mice. Hepatic steatosis, the morphology of adipocytes, adiposity assessed by computed tomography, and the expression of genes related to glucose or lipid metabolism and inflammation in the liver and fat tissues showed no notable differences in db/db mice. Global gene expression analysis of isolated islets indicated that the genes related to regulation of cell population proliferation and negative regulation of cell death were enriched by Imeg + Met treatment in db/db islets. In vitro culture experiments confirmed the protective effects of Imeg + Met against ß-cell apoptosis. The expression of Snai1, Tnfrsf18, Pdcd1, Mmp9, Ccr7, Egr3, and Cxcl12, some of which have been linked to apoptosis, in db/db islets was attenuated by Imeg + Met. Treatment of a ß-cell line with Imeg + Met prevented apoptosis induced by hydrogen peroxide or palmitate. Thus, the combination of imeglimin and metformin is beneficial for the maintenance of ß-cell mass in db/db mice, probably through direct action on ß-cells, suggesting a potential strategy for protecting ß-cells in the treatment of type 2 diabetes.

A Disproportionality Analysis of the Adverse Effect Profiles of Methimazole and Propylthiouracil in Patients with Hyperthyroidism Using the Japanese Adverse Drug Event Report Database.

Background: Antithyroid drugs (ATDs) are frequently used to achieve euthyroidism in patients with hyperthyroidism. ATDs cause characteristic common and rare adverse events; however, comprehensive comparisons between methimazole (MMI) and propylthiouracil (PTU) in terms of adverse events are limited. Methods: In this study, we thoroughly explored adverse events in association with MMI and PTU use with a disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database and evaluated the prevalence of MMI and PTU prescriptions using the National Database of Health Insurance Claims and Specific Health Checkups (NDB) Open Data Japan. We analyzed 3271 cases of MMI use and 1029 cases of PTU use with respect to 9789 preferred terms (PTs) for adverse events registered in the JADER database by calculating and comparing reporting odds ratios (RORs). Results: We found that 8 PTs, including agranulocytosis (p < 0.0001, 4.01-fold), aplasia cutis congenita (p < 0.0001, 123.22-fold), and exomphalos (p = 0.0002, 22.17-fold), demonstrated significantly higher RORs (more than 4-fold) for MMI use than for PTU use. Nineteen PTs, including anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (p < 0.0001, 29.84), rapidly progressive glomerulonephritis (p < 0.0001, 6.44), and pulmonary alveolar hemorrhage (p < 0.0001, 7.77), had RORs for PTU use more than four times those for MMI use. NDB Open Data Japan showed more frequent PTU prescriptions than MMI prescriptions for women of reproductive age. Conclusions: This large-scale study confirmed that a variety of congenital malformations were identified as having significantly high RORs for MMI use, while diseases related to ANCA-associated vasculitis were specific to PTU.

Signaling pathways that regulate adaptive ß-cell proliferation for the treatment of diabetes.

The decline in ß-cell mass due to the failure of ß-cell compensation is one cause of the development of type 2 diabetes. Therefore, elucidation of the mechanism by which an adaptive increase in ß-cell mass occurs in vivo will lead to the development of a cure for diabetes. Insulin and insulin receptor (IR)-mediated signaling pathways play an important role in the mechanism that increases ß-cell mass by compensatory ß-cell proliferation in response to chronic insulin resistance. However, whether IR is required for compensatory ß-cell proliferation remains controversial in some situations. It might be possible that IR acts as a scaffold for the signaling complex independent of its ligand. It has also been reported that the forkhead box protein M1/polo-like kinase 1/centromere protein A pathway plays a central role in adaptive ß-cell proliferation during diet-induced obesity, hyperglycemia, pregnancy, aging and acute insulin resistance. We recently reported that the cross-talk of islets with fat tissue, in addition to the liver, through humoral factors is involved in adaptive ß-cell proliferation. This accommodative response of ß-cell proliferation through adipocytes was observed particularly under an acute insulin resistance state in an IR/insulin signal-independent and forkhead box protein M1/polo-like kinase 1/centromere protein A pathway-dependent manner. A remaining barrier for the treatment of human diabetes using ß-cells is the differences between human and rodent islets. In this review, the focus is on signaling pathways that regulate adaptive ß-cell proliferation for the treatment of diabetes considering the abovementioned issues.

Zinc and iron dynamics in human islet amyloid polypeptide-induced diabetes mouse model.

Metal homeostasis is tightly regulated in cells and organisms, and its disturbance is frequently observed in some diseases such as neurodegenerative diseases and metabolic disorders. Previous studies suggest that zinc and iron are necessary for the normal functions of pancreatic ß cells. However, the distribution of elements in normal conditions and the pathophysiological significance of dysregulated elements in the islet in diabetic conditions have remained unclear. In this study, to investigate the dynamics of elements in the pancreatic islets of a diabetic mouse model expressing human islet amyloid polypeptide (hIAPP): hIAPP transgenic (hIAPP-Tg) mice, we performed imaging analysis of elements using synchrotron scanning X-ray fluorescence microscopy and quantitative analysis of elements using inductively coupled plasma mass spectrometry. We found that in the islets, zinc significantly decreased in the early stage of diabetes, while iron gradually decreased concurrently with the increase in blood glucose levels of hIAPP-Tg mice. Notably, when zinc and/or iron were decreased in the islets of hIAPP-Tg mice, dysregulation of glucose-stimulated mitochondrial respiration was observed. Our findings may contribute to clarifying the roles of zinc and iron in islet functions under pathophysiological diabetic conditions.

Protective effects of S100A8 on sepsis mortality: Links to sepsis risk in obesity and diabetes.

Obesity and diabetes are independent risk factors for death during sepsis. S100A8, an alarmin, is related to inflammation, obesity, and diabetes. Here, we examine the role of S100A8 in sepsis of obesity and diabetes models. Injection of S100A8 prolongs the survival of septic mice induced by lethal endotoxemia, Escherichia coli injection, or cecal ligation and puncture. S100A8 decrease the LPS-induced expression of proinflammatory cytokines in peritoneal macrophages by inhibiting TLR4-mediated signals in an autocrine manner. db/db, ob/ob, and western diet-fed mice demonstrate reduced upregulation of S100A8 induced by LPS treatment in both serum and peritoneal cells. These mice also show shorter survival after LPS injection, and S100A8 supplementation prolonged the survival. While myelomonocytic cells-specific S100A8-deficient mice (Lyz2 cre :S100A8 floxed/floxed ) exhibit shorter survival after LPS treatment, S100A8 supplementation prolonged the survival. Thus, myelomonocytic cell-derived S100A8 is crucial for protection from sepsis, and S100A8 supplementation improves sepsis, particularly in mice with obesity and diabetes.

Association between circulating SerpinB1 levels and insulin sensitivity in Japanese with type 2 diabetes: A single-center, cross-sectional, observational study.

Plasma and liver SerpinB1 levels are elevated in mice with insulin resistance and promote ß-cell proliferation in human islets. We measured serum SerpinB1 levels in Japanese subjects with or without type 2 diabetes (T2DM). We enrolled 12 normal glucose tolerance (NGT) and 51 T2DM subjects. There was no difference in serum SerpinB1 levels between the 2 groups (T2DM, 1.3 ± 0.9 ng/mL vs. NGT, 1.8 ± 1.7 ng/mL; P = 0.146). After adjusting for age and sex, the serum SerpinB1 levels were positively correlated with HOMA2-%S (ß = 0.319, P = 0.036), and negatively correlated with fasting blood glucose (ß = -0.365, P = 0.010), total cholesterol (ß = -0.396, P = 0.006), low-density lipoprotein (LDL) cholesterol (ß = -0.411, P = 0.004), triglycerides (ß = -0.321, P = 0.026), and γGTP (ß = -0.322, P = 0.026) in subjects with T2DM. Thus, circulating SerpinB1 is possibly associated with insulin sensitivity and better blood glucose level in Japanese subjects with T2DM. Trial registration: UMIN Clinical Trials Registry, UMIN000020453.

E2F1 transcription factor mediates a link between fat and islets to promote ß cell proliferation in response to acute insulin resistance.

Prevention or amelioration of declining ß cell mass is a potential strategy to cure diabetes. Here, we report the pathways utilized by ß cells to robustly replicate in response to acute insulin resistance induced by S961, a pharmacological insulin receptor antagonist. Interestingly, pathways that include CENP-A and the transcription factor E2F1 that are independent of insulin signaling and its substrates appeared to mediate S961-induced ß cell multiplication. Consistently, pharmacological inhibition of E2F1 blocks ß-cell proliferation in S961-injected mice. Serum from S961-treated mice recapitulates replication of ß cells in mouse and human islets in an E2F1-dependent manner. Co-culture of islets with adipocytes isolated from S961-treated mice enables ß cells to duplicate, while E2F1 inhibition limits their growth even in the presence of adipocytes. These data suggest insulin resistance-induced proliferative signals from adipocytes activate E2F1, a potential therapeutic target, to promote ß cell compensation.

Uncoupling protein 2 and aldolase B impact insulin release by modulating mitochondrial function and Ca2+ release from the ER.

Uncoupling protein 2 (UCP2), a mitochondrial protein, is known to be upregulated in pancreatic islets of patients with type 2 diabetes (T2DM); however, the pathological significance of this increase in UCP2 expression is unclear. In this study, we highlight the molecular link between the increase in UCP2 expression in ß-cells and ß-cell failure by using genetically engineered mice and human islets. ß-cell-specific UCP2-overexpressing transgenic mice (ßUCP2Tg) exhibited glucose intolerance and a reduction in insulin secretion. Decreased mitochondrial function and increased aldolase B (AldB) expression through oxidative-stress-mediated pathway were observed in ßUCP2Tg islets. AldB, a glycolytic enzyme, was associated with reduced insulin secretion via mitochondrial dysfunction and impaired calcium release from the endoplasmic reticulum (ER). Taken together, our findings provide a new mechanism of ß-cell dysfunction by UCP2 and AldB. Targeting the UCP2/AldB axis is a promising approach for the recovery of ß-cell function.

Abdominal aortic calcification is associated with Fibrosis-4 index and low body mass index in type 2 diabetes patients: A retrospective cross-sectional study.

AIMS/INTRODUCTION: This study aimed to clarify the nature of the relationship between the abdominal aortic calcification (AAC) grade and the presence of cardiovascular diseases, and determine factors related to AAC grade in people with type 2 diabetes mellitus. MATERIALS AND METHODS: This retrospective cross-sectional study enrolled 264 inpatients with type 2 diabetes mellitus. The AAC score and length were measured using the lateral abdominal radiographs. Logistic regression models were used to assess the associations between AAC scores/lengths and the presence of coronary artery disease (CAD), cerebral infarction (CI) and peripheral artery disease (PAD). The correlation between AAC scores/lengths and other clinical factors were evaluated using linear regression models. RESULTS: The AAC score was significantly correlated with prevalent CAD and CI independent of age and smoking, but not with the prevalence of PAD. AAC length was not significantly correlated with the presence of CAD, CI or PAD; however, the sample size was insufficient to conclude, probably due to low prevalence. Both the AAC score and length were correlated inversely with body mass index (BMI) and, with the Fibrosis-4 (Fib-4) index >2.67; these correlations were significant after adjusting for cardiovascular risk factors and BMI, although AAC was not associated with ultrasonography-diagnosed fatty liver. There was a significant interaction between BMI and Fib-4 index; lower BMI and Fib-4 index >2.67 showed a synergistic association with high AAC grade. CONCLUSIONS: AAC score is associated with CAD and CI morbidity in participants with type 2 diabetes mellitus. Low BMI and Fib-4 index >2.67 can be valuable indicators of AAC in people with type 2 diabetes mellitus.

The multifaceted role of ATF4 in regulating glucose-stimulated insulin secretion.

Stress-inducible transcription factor ATF4 is essential for survival and identity of ß-cell during stress conditions. However, the physiological role of ATF4 in ß-cell function is not yet completely understood. To understand the role of ATF4 in glucose-stimulated insulin secretion (GSIS), ß-cell-specific Atf4 knockout (ßAtf4KO) mice were phenotypically characterized. Insulin secretion and mechanistic analyses were performed using islets from control Atf4f/f and ßAtf4KO mice to assess key regulators for triggering and amplifying signals for GSIS. ßAtf4KO mice displayed glucose intolerance due to reduced insulin secretion. Moreover, ßAtf4KO islets exhibited a decrease in both the insulin content and first-phase insulin secretion. The analysis of ßAtf4KO islets showed that ATF4 is required for insulin production and glucose-stimulated ATP and cAMP production. The results demonstrate that ATF4 contributes to the multifaceted regulatory process in GSIS even under stress-free conditions.

Recent developments in Phos-tag electrophoresis for the analysis of phosphoproteins in proteomics.

INTRODUCTION: Phosphate-binding tag (Phos-tag) sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is an important development capable of analyzing the phosphorylation state of proteins. Conventionally, proteins were separated via SDS-PAGE and Phos-tag SDS-PAGE that use different gels to identify phosphorylated proteins. However, it was often difficult to compare the electrophoretic mobility of the proteins in the different gels used. The recently developed Phos-tag diagonal electrophoresis has been able to solve this problem. It can indicate the SDS-PAGE and Phos-tag SDS-PAGE patterns on a single gel; therefore, phosphorylated proteins can be distinguished easily from non-phosphorylated proteins. AREAS COVERED: This review assesses the importance of Phos-tag electrophoresis, which enables the analysis of protein phosphorylation states, in the field of proteomics. Additionally, this review describes the significance and actual experimental technique of Phos-tag diagonal electrophoresis, which was recently developed to overcome the drawbacks of Phos-tag SDS-PAGE. EXPERT OPINION: Although shotgun analysis of proteins allows detecting many phosphorylation sites, it is challenging to clarify the differences in the phosphorylation states of protein molecules using this technique. Therefore, Phos-tag SDS-PAGE is frequently used to determine the phosphorylation state of proteins. This technique has become more powerful with the recent development of Phos-tag diagonal electrophoresis.Abbreviations: BIS, N,N'-methylenebis(acrylamide); CBB, Coomassie brilliant blue R250; ESI, electrospray ionization; hnRNP, heterogeneous ribonucleoprotein K; LTQ-Orbitrap, Linear trap quadrupole-Orbitrap; LC, liquid chromatography; MS, mass spectrometry; MALDI, matrix-assisted laser desorption ionization; Phos-tag, phosphate-binding tag [1,3-bis [bis (pyridine-2-ylmethyl) amino] propane-2-olate]; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; TOF, time of flight; 2D-DIGE, fluorescence-labeled two-dimensional difference gel electrophoresis; 2-DE, two-dimensional gel electrophoresis.

Insulin regulates arginine-stimulated insulin secretion in humans.

AIMS: Insulin potentiates glucose-stimulated insulin secretion. These effects are attenuated in beta cell-specific insulin receptor knockout mice and insulin resistant humans. This investigation examines whether short duration insulin exposure regulates beta cell responsiveness to arginine, a non-glucose secretagogue, in healthy humans. MATERIALS AND METHODS: Arginine-stimulated insulin secretion was studied in 10 healthy humans. In each subject arginine was administered as a bolus followed by continuous infusion on two occasions one month apart, after sham/saline or hyperinsulinemic-isoglycemic clamp, respectively providing low and high insulin pre-exposure conditions. Arginine-stimulated insulin secretion was measured by C-peptide deconvolution, and by a selective immunogenic (DAKO) assay for direct measurement of endogenous but not exogenous insulin. RESULTS: Pre-exposure to exogenous insulin augmented arginine-stimulated insulin secretion. The effect was seen acutely following arginine bolus (endogenous DAKO insulin incremental AUC240-255min 311.6 ±â€¯208.1 (post-insulin exposure) versus 120.6 ±â€¯42.2 µU/ml•min (sham/saline) (t-test P = 0.021)), as well as in response to continuous arginine infusion (DAKO insulin incremental AUC260-290min 1095.3 ±â€¯592.1 (sham/saline) versus 564.8 ±â€¯207.1 µU/ml•min (high insulin)(P = 0.009)). Findings were similar when beta cell response was assessed using C-peptide, insulin secretion rates by deconvolution, and the C-peptide to glucose ratio. CONCLUSIONS: We demonstrate a physiologic role of insulin in regulation of the beta cell secretory response to arginine.

Imeglimin Ameliorates ß-Cell Apoptosis by Modulating the Endoplasmic Reticulum Homeostasis Pathway.

The effects of imeglimin, a novel antidiabetes agent, on ß-cell function remain unclear. Here, we unveiled the impact of imeglimin on ß-cell survival. Treatment with imeglimin augmented mitochondrial function, enhanced insulin secretion, promoted ß-cell proliferation, and improved ß-cell survival in mouse islets. Imeglimin upregulated the expression of endoplasmic reticulum (ER)-related molecules, including Chop (Ddit3), Gadd34 (Ppp1r15a), Atf3, and Sdf2l1, and decreased eIF2α phosphorylation after treatment with thapsigargin and restored global protein synthesis in ß-cells under ER stress. Imeglimin failed to protect against ER stress-induced ß-cell apoptosis in CHOP-deficient islets or in the presence of GADD34 inhibitor. Treatment with imeglimin showed a significant decrease in the number of apoptotic ß-cells and increased ß-cell mass in Akita mice. Imeglimin also protected against ß-cell apoptosis in both human islets and human pluripotent stem cell-derived ß-like cells. Taken together, imeglimin modulates the ER homeostasis pathway, which results in the prevention of ß-cell apoptosis both in vitro and in vivo.

Validity and reliability of the Japanese version of the diabetes knowledge test among in-patients with type 2 diabetes.

AIMS/INTRODUCTION: The diabetes knowledge test (DKT) is unavailable in Japan. In this study, we developed and evaluated a Japanese version of the DKT (J-DKT) for in-patients with type 2 diabetes before and after receiving diabetes education. MATERIALS AND METHODS: The J-DKT contains 12 questions (0-12 points) to assess knowledge regarding diabetes, its complications, and diabetic nutrition therapy. During the median 10 days of hospitalization, 107 patients with type 2 diabetes received diabetes education (20 min private lessons every day from physicians, two nutrition counselling programs from dietitians, and a 2 h group session conducted by physicians, dietitians, and nurses). The J-DKT was administered on admission and before discharge. To confirm the J-DKT's reliability, we assessed the internal consistency using Cronbach's α (≥0.70 was considered acceptable). To evaluate its validity, we investigated changes in the J-DKT total scores after the education programs and examined the differences in the scores among groups classified based on patient characteristics such as age, diabetes-related hospitalization history, and hospitalization duration. RESULTS: The J-DKT total scores increased from 5 to 8 (P ˂ 0.01) after the education programs. The J-DKT before and after the program showed a Cronbach's α of 0.48 and 0.73, respectively. Except for age, baseline characteristics such as history and period of hospitalization for diabetes were not associated with the J-DKT scores after the education program. CONCLUSIONS: The validity and reliability of the J-DKT after the diabetes education program were acceptable in this study.

Translational research on human pancreatic ß-cell mass expansion for the treatment of diabetes.

The structural, functional, and pathological differences between human islets and rodent islets, such as mouse or rat islets, have been clarified, and research using human islets is becoming more important for elucidating the pathophysiology of diabetes and developing therapeutic strategies for diabetes. Increasing the functional human ß-cell mass is a feasible method for the treatment of both type 1 and type 2 diabetes. The glucokinase-mediated glucose signaling pathway is known to promote ß-cell proliferation not only in rodent models but also in humans. However, little is known about the signaling components of glucose- or glucokinase-mediated signaling pathways. Studies have gradually revealed the involvement of ER stress-related molecules, cell cycle regulators, inflammatory proteins, extracellular matrix proteins, and neurotransmitters in the glucokinase-mediated signaling pathway in ß-cells. Unraveling the mechanisms of those molecules in the regulation of human ß-cell mass will provide new insights into how the functional ß-cell mass can be increased. The human islet distribution program is essential for human islet research. However, human islets for research are only available by import from Europe and America into Japan or Asia. Since Japanese or Asian diabetes patients possibly show different features compared with European or American diabetes patients, studies using human islets from Japanese or Asian populations have become important for the elucidation of pathophysiology in these specific population groups. This review outlines new pathways important for the regulation of human pancreatic ß-cell mass and expectations regarding the establishment of a human islet distribution program in Japan.

Immediate Glucose-Lowering Effect After the First Administration of Dulaglutide: A Retrospective, Single-Center, Observational Study.

INTRODUCTION: Dulaglutide is a long-acting glucagon-like peptide 1 receptor agonist that is administered once weekly for the treatment of type 2 diabetes. However, the immediate glucose-lowering effect of dulaglutide after the first administration and the factors affecting the efficacy of the drug remain unclear. METHODS: This study was a retrospective and observational study of 80 subjects with type 2 diabetes conducted in a hospitalized setting. The changes (Δ) in the blood glucose (BG) levels at six time points (6-point BG levels) from the baseline (day - 1) to the day after the first administration of 0.75 mg of dulaglutide (day 1) were evaluated. The associations of the Δ 6-point BG levels with the patients' characteristics and laboratory data were also analyzed. RESULTS: Significant reduction of the fasting BG, preprandial BG, postprandial BG, and standard deviation (SD) of the 6-point BG levels was observed on day 1 as compared to day - 1 (P < 0.0001) and the reduced BG levels were maintained throughout the remaining observation period of 5 days. The baseline serum hemoglobin A1c and glycoalbumin levels were positively correlated with the reduction of the fasting BG. The Δ BG levels were not related to the parameters of insulin-secreting capacity. Insulin treatment was positively associated with the reduction of the 6-point BG levels. Patients without cerebrovascular disease and patients without diabetic retinopathy showed greater improvements of the fasting BG and SD of the 6-point BG levels, respectively. Urinary microalbumin level was positively correlated with improvements of the 6-point BG levels. Dulaglutide reduced the BG levels, irrespective of the previously used class of antidiabetic medication(s). CONCLUSION: Dulaglutide achieved reduction in glucose level within 24 h of the first injection. The improvement in the BG levels remained stable for a week in the hospitalized clinical setting.