Linagliptin Ameliorates Hepatic Steatosis via Non-Canonical Mechanisms in Mice Treated with a Dual Inhibitor of Insulin Receptor and IGF-1 Receptor.

Abnormal hepatic insulin signaling is a cause or consequence of hepatic steatosis. DPP-4 inhibitors might be protective against fatty liver. We previously reported that the systemic inhibition of insulin receptor (IR) and IGF-1 receptor (IGF1R) by the administration of OSI-906 (linsitinib), a dual IR/IGF1R inhibitor, induced glucose intolerance, hepatic steatosis, and lipoatrophy in mice. In the present study, we investigated the effects of a DPP-4 inhibitor, linagliptin, on hepatic steatosis in OSI-906-treated mice. Unlike high-fat diet-induced hepatic steatosis, OSI-906-induced hepatic steatosis is not characterized by elevations in inflammatory responses or oxidative stress levels. Linagliptin improved OSI-906-induced hepatic steatosis via an insulin-signaling-independent pathway, without altering glucose levels, free fatty acid levels, gluconeogenic gene expressions in the liver, or visceral fat atrophy. Hepatic quantitative proteomic and phosphoproteomic analyses revealed that perilipin-2 (PLIN2), major urinary protein 20 (MUP20), cytochrome P450 2b10 (CYP2B10), and nicotinamide N-methyltransferase (NNMT) are possibly involved in the process of the amelioration of hepatic steatosis by linagliptin. Thus, linagliptin improved hepatic steatosis induced by IR and IGF1R inhibition via a previously unknown mechanism that did not involve gluconeogenesis, lipogenesis, or inflammation, suggesting the non-canonical actions of DPP-4 inhibitors in the treatment of hepatic steatosis under insulin-resistant conditions.

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.

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.

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.

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.

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.

The Feasibility and Applicability of Stem Cell Therapy for the Cure of Type 1 Diabetes.

Stem cell therapy using islet-like insulin-producing cells derived from human pluripotent stem cells has the potential to allow patients with type 1 diabetes to withdraw from insulin therapy. However, several issues exist regarding the use of stem cell therapy to treat type 1 diabetes. In this review, we will focus on the following topics: (1) autoimmune responses during the autologous transplantation of stem cell-derived islet cells, (2) a comparison of stem cell therapy with insulin injection therapy, (3) the impact of the islet microenvironment on stem cell-derived islet cells, and (4) the cost-effectiveness of stem cell-derived islet cell transplantation. Based on these various viewpoints, we will discuss what is required to perform stem cell therapy for patients with type 1 diabetes.

Asymptomatic meningitis diagnosed by positron emission tomography in a patient with syndrome of inappropriate antidiuretic hormone secretion: a case report.

BACKGROUND: Syndrome of inappropriate antidiuretic hormone secretion can be caused by arginine-vasopressin-producing tumors or enhanced arginine vasopressin secretion from the posterior pituitary gland due to central nervous system disorders and intrathoracic diseases. CASE PRESENTATION: A 53-year-old Asian man was hospitalized with complaints of tremor and hiccups. Laboratory examination revealed findings suggestive of hypotonic hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion. The patient did not complain of headache or photophobia, and showed no signs of meningeal irritation. Positron emission tomography-computed tomography revealed 18F-fluoro-deoxy-glucose accumulation along the cervical spinal cord, based on which the patient was diagnosed as having aseptic meningitis. The hyponatremia was treated successfully by fluid restriction, and optimum plasma sodium concentration was maintained by tolvaptan administration. CONCLUSIONS: This case underscores the need to consider the possibility of mild meningitis as the cause of syndrome of inappropriate antidiuretic hormone secretion in patients without other identifiable cause.

Association of the plasma xanthine oxidoreductase activity with the metabolic parameters and vascular complications in patients with type 2 diabetes.

Xanthine oxidoreductase (XOR) catalyzes the oxidation of hypoxanthine to xanthine, and of xanthine to uric acid. XOR also enhances the production of reactive oxygen species and causes endothelial dysfunction. In this study, we evaluated the association of XOR and its substrate with the vascular complications in 94 Japanese inpatients with type 2 diabetes (T2DM). The plasma XOR activity and plasma xanthine levels were positively correlated with the body mass index, aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-GTP, fasting plasma insulin, and the homeostasis model of assessment of insulin resistance (HOMA-IR), and negatively correlated with the high density lipoprotein cholesterol. The plasma XOR activity also showed a positive correlation with the serum triglyceride. Multivariate analyses identified AST, ALT, fasting plasma insulin and HOMA-IR as being independently associated with the plasma XOR activity. The plasma XOR activity negatively correlated with the duration of diabetes, and positively correlated with the coefficient of variation of the R-R interval and sensory nerve conduction velocity. Furthermore, the plasma XOR activity was significantly decreased in patients with coronary artery disease. Thus, the plasma XOR activity might be a surrogate marker for the development of vascular complications, as well as liver dysfunction and insulin resistance, in T2DM.Trial registration: This study is registered at the UMIN Clinical Trials Registry (UMIN000029970; https://www.umin.ac.jp/ctr/index-j.htm ). The study was conducted from Nov 15, 2017.

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.

Soluble EGFR, a hepatokine, and adipsin, an adipokine, are biomarkers correlated with distinct aspects of insulin resistance in type 2 diabetes subjects.

BACKGROUND: Insulin resistance can occur in all metabolic organs including the liver, adipose tissue, and skeletal muscles. Circulating soluble epidermal growth factor receptor (soluble EGFR) and adipsin levels are altered in obese diabetic mice and are possibly correlated with insulin resistance in both mice and humans. Here, we investigated the significance of soluble EGFR and adipsin as biomarkers for insulin resistance in Japanese subjects with type 2 diabetes. METHODS: We measured the soluble EGFR and adipsin levels in sera from 47 non-diabetic subjects and 106 subjects with type 2 diabetes using enzyme-linked immunosorbent assays (ELISAs) and analyzed the correlations between the soluble EGFR or adipsin levels and metabolic parameters in type 2 diabetes subjects. We also measured the gene expression levels of Egfr and Cfd (adipsin) in the liver, adipose tissue, and skeletal muscle in mice with/without obesity or diabetes. RESULTS: The soluble EGFR levels were correlated with the fasting blood glucose level (P = 0.010), HOMA-IR (P = 0.035), HbA1c level (P = 0.007), HDL-cholesterol level (P = 0.044), and FIB-4 index (P = 0.017) after adjustments for age, sex, and total cholesterol levels. These factors are known to be related to hepatic insulin resistance. The serum adipsin levels were correlated with BMI (P < 0.001), waist circumference (P < 0.001), fasting serum insulin level (P = 0.001), HOMA-IR (P = 0.009), CPR-index (P = 0.045), and FIB-4 index (P = 0.007) after adjustments for age, sex and eGFR levels. Abdominal adiposity leads to the potentiation of these factors. The expression of Egfr was abundant in the liver, while Cfd was predominantly expressed in adipose tissue in mice. CONCLUSIONS: Soluble EGFR, a hepatokine, is correlated with insulin resistance in the liver, while adipsin, an adipokine, is associated with adipose insulin resistance.Trial registration: UMIN Clinical Trials Registry (www.umin.ac.jp), UMIN000020474. Registered 8 January 2016.

Epidemiological study of hantavirus infection in the Samara Region of European Russia.

European Russia is a highly endemic area of hemorrhagic fever with renal syndrome (HFRS), a rodent-borne zoonotic disease, caused by hantaviruses. In total, 145 small mammals of four species (Myodes glareolus, Apodemus flavicollis, A. agrarius, and A. uralensis) were trapped in the Samara region of European Russia in August 2005 and examined for the presence of hantavirus (HV). Anti-HV antibodies were found in six of 68 (8.8%) M. glareolus and in one of 19 (5.3%) A. flavicollis by indirect immunofluorescent antibody assay (IFA). The Puumala virus (PUUV), which is one of the hantavirus species, was detected in the lungs of seven M. glareolus by RT-PCR. The virus S-segment was extremely similar (96.2% to 99.3%) to the sequence found in a fatal case of HFRS in the Samara region. Phylogenetic analyses of S and M segments showed that the Samara PUUVs form a cluster within the Russian Volga lineage and apparently differ from other European PUUVs. Anti-PUUV antibodies were found in blood sera from seven HFRS patients and from one undiagnosed patient from the Samara region, using IFA and an enzyme-linked immunosorbent assay (ELISA). These data suggest that the bank vole M. glareolus is a primary natural reservoir and vector for PUUV, which is the main causative agent of HFRS in humans in the Samara region.

Genetic and antigenic analyses of a Puumala virus isolate as a potential vaccine strain.

Puumala virus (PUUV), a causative agent of hemorrhagic fever with renal syndrome (HFRS), is prevalent in Europe and European Russia. No vaccine has been developed for PUUV-associated HFRS, primarily because of the low viral yield in cultured cells. A PUUV strain known as DTK/Ufa-97 was isolated in Russia and adapted for growth in Vero E6 cells maintained in serum-free medium. The DTK/Ufa-97 strain produced a higher viral titer in serum-free medium, suggesting that it may prove useful in the development of an HFRS vaccine. When PUUV-infected Vero E6 cells were grown in serum-free medium, the DTK/Ufa-97 strain yielded more copies of intracellular viral RNA and a higher viral titer in the culture fluid than did the Sotkamo strain. Phylogenetic analysis revealed that PUUVs can be classified into multiple lineages according to geographical origin, and that the DTK/Ufa-97 strain is a member of the Bashkiria-Saratov lineage. The deduced amino acid sequences of the small, medium, and large segments of the DTK/Ufa-97 strain were 99.2% to 100%, 99.3% to 99.8%, and 99.8% identical, respectively, to those of the Bashkirian PUUV strains and 96.9%, 92.6%, and 97.4% identical, respectively, to those of the Sotkamo strain, indicating that the PUUVs are genetically diverse. However, DTK/Ufa-97 and other strains of PUUV exhibited similar patterns of binding to a panel of monoclonal antibodies against Hantaan virus. In addition, diluted antisera (i.e., ranging from 1:160 to 1:640) specific to three strains of PUUV neutralized both homologous and heterologous viruses. These results suggest that the DTK/Ufa-97 strain is capable of extensive growth and is antigenically similar to genetically distant strains of PUUV.

Development of a serotyping enzyme-linked immunosorbent assay system based on recombinant truncated hantavirus nucleocapsid proteins for New World hantavirus infection.

New World hantaviruses were divided into five groups based on the amino acid sequence variability of the internal variable region (around 230-302 amino acids) of hantavirus nucleocapsid protein (NP). Sin Nombre virus (SNV), Andes virus, Black Creek Canal virus (BCCV), Carrizal virus (CARV) and Cano Delgadito virus belong to groups 1, 2, 3, 4 and 5, respectively. Patient and rodent sera were serotyped successfully by an enzyme-linked immunosorbent assay (ELISA) with recombinant truncated NP lacking 99 N-terminal amino acids (trNP100) of SNV, CARV and BCCV. The trNP100 of BCCV showed lower reactivity to heterologous sera. In contrast, whole recombinant NP antigens detected both homologous and heterologous antibodies equally. The results together with results of a previous study suggest that trNP100 can distinguish infections among viruses in groups 1, 2, 3 and 4 of New World hantaviruses. The serotyping ELISA with trNP100 is useful for epidemiological surveillance in humans and rodents.

Ecology of hantaviruses in Mexico: genetic identification of rodent host species and spillover infection.

In our recent epidemiological survey conducted in Mexico for hantavirus infection, we identified three distinct viruses circulating in Mexican wild rodents, namely Montano virus (MTNV), Huitzilac virus (HUIV), and Carrizal virus (CARV). To gain a detailed understanding of hantavirus epidemiology and its associated hosts, 410 rodents were captured at eight collecting points in Morelos and Guerrero, Mexico, and examined for hantavirus seroprevalence, the presence of viral RNA, and rodent host species identification using cytochrome b gene sequences. Of the 32 species captured, seven species were positive for hantavirus: Peromyscus beatae (31/127; 24.4%), Reithrodontomys sumichrasti (6/15; 40%), Reithrodontomys megalotis (2/25; 8%), Peromyscus aztecus evides (1/1; 100%), Peromyscus megalops (1/41; 2.4%), Megadontomys thomasi (1/9; 11.1%), and Neotoma picta (1/6; 16.7%), with an overall prevalence of 10.5%; virus genome persisted in the majority of seropositive rodents. Nucleotide sequence and phylogenetic analysis showed that the viruses belonged mainly to the three lineages previously identified. The data showed that MTNV and CARV were primarily carried by P. beatae and R. sumichrasti, respectively. In addition, the data revealed an apparent complex interaction between hantaviruses and their hosts, suggesting active transmission and/or spillover infections within sympatric rodent species.

Genetic diversity of hantaviruses in Mexico: identification of three novel hantaviruses from Neotominae rodents.

A variety of hantaviruses are harbored by rodents in North and South America, some of which can cause hantavirus pulmonary syndrome. To obtain greater evolutionary insight into hantaviruses in the Americas, a total of 211 rodents were captured in the Mexican states of Guerrero and Morelos in 2006. Anti-hantavirus antibodies were detected in 27 of 211 serum samples (12.8%) by ELISA. The distribution of seropositive rodents was: 17 Peromyscus beatae, 1 Megadontomys thomasi, 1 Neotoma picta, 6 Reithrodontomys sumichrasti, and 2 Reithrodontomys megalotis. The hantavirus small (S), medium (M), and large (L) genome segments from P. beatae, R. sumichrasti, and R. megalotis were amplified and the sequences covering the open reading frames were determined. The hantaviruses from P. beatae, R. sumichrasti, and R. megalotis were provisionally designated Montano (MTN), Carrizal (CAR), and Huitzilac (HUI), respectively. The M segment amino acid identities among the Mexican hantaviruses were 80.8-93.0%. When these M segments were compared to those of known hantaviruses, MTN virus was most closely related to Limestone Canyon (LSC) virus (88.9% amino acid identity), while the CAR and HUI viruses were most closely related to El Moro Canyon (ELMC) virus (90-91% identity). Phylogenetic analysis revealed that the MTN, CAR, and HUI viruses occupy a monophyletic clade with the LSC, ELMC, and Rio Segundo viruses, which are harbored by Peromyscus boylii, R. megalotis, and Reithrodontomys mexicanus, respectively. The data obtained in this study provide important information for understanding the evolution of hantaviruses in the Americas.

Mode of infection of Hokkaido virus (Genus Hantavirus) among grey red-backed voles, Myodes rufocanus, in Hokkaido, Japan.

Hokkaido virus (HOKV) is a member of the genus Hantavirus, in the family Bunyaviridae. To investigate HOKV infection in the host Myodes rufocanus, the grey red-backed vole, 199 animals were captured at Tobetsu (October 2004 and July 2005) and Nakagawa (October 2004) in Hokkaido, Japan, for detection of antibody, antigen, and viral RNA. In the surveys in Tobetsu (2004) and Nakagawa (2004), seropositive animals were detected at a frequency of 6.0% (5/84) and 10.4% (5/48), respectively. No seropositive animals were detected in Tobetsu in 2005. Seroprevalence in males in Tobetsu and Nakagawa in 2004 was 25% (1/4) and 45.5% (5/11), respectively, which was higher than in females, at 5.0% (4/80) and 0% (0/37), respectively (P<0.01). These results suggest that male animals play an important role in the maintenance of HOKV in M. rufocanus. Two females were seronegative but viral RNA-positive, indicating that these animals had acute infections before antibody was produced. Another five infected animals in Nakagawa were all male and had high levels of antibodies and viral RNA, suggesting that they had persistent infections. Viral RNA copies in organs of infected animals in Nakagawa were quantified by real-time polymerase chain reaction. Two acutely infected animals had > or = 10 times the number of RNA copies in their lungs compared to those of persistently infected animals. In most cases, lungs or spleen had the highest RNA copy number, regardless of infection status.