Two case reports of continued progression of chronic ocular graft-versus-host disease without concurrent systemic comorbidities treated by amniotic membrane transplantation.

BACKGROUND: Chronic ocular graft-versus-host disease (oGVHD) is an ocular comorbidity of graft-versus-host disease (GVHD) that usually occurs concurrently with systemic manifestations. Failure to detect and treat oGVHD in its early stages may lead to progression of ocular signs and symptoms leading to oGVHD that is refractory to conventional treatment. CASE PRESENTATION: We report the clinical course of a 19-year-old male and a 59-year-old female with severe and progressive chronic oGVHD without concurrent systemic signs of chronic graft-versus-host disease (cGVHD). Although their systemic conditions had been stable, both suffered from severe oGVHD and were referred to our clinic. Both cases exhibited marked improvement in conjunctival inflammation and fibrotic changes after amniotic membrane transplantation (AMT). Both cases underwent keratoplasty eventually to stabilize ocular surface conditions and to improve visual function. CONCLUSIONS: We reported the clinical outcomes of 2 cases of chronic oGVHD without concurrent systemic comorbidities that were treated with AMT. The clinician should be aware that cGVHD may persist in target organs even in the absence of concurrent systemic comorbidities following seemingly successful systemic treatment. A multidisciplinary team approach is essential in the early detection and therapeutic intervention for chronic oGVHD.

The D614G mutation in the SARS-CoV2 Spike protein increases infectivity in an ACE2 receptor dependent manner.

The SARS-CoV2 coronavirus responsible for the current COVID19 pandemic has been reported to have a relatively low mutation rate. Nevertheless, a few prevalent variants have arisen that give the appearance of undergoing positive selection as they are becoming increasingly widespread over time. Most prominent among these is the D614G amino acid substitution in the SARS-CoV2 Spike protein, which mediates viral entry. The D614G substitution, however, is in linkage disequilibrium with the ORF1b P314L mutation where both mutations almost invariably co-occur, making functional inferences problematic. In addition, the possibility of repeated new introductions of the mutant strain does not allow one to distinguish between a founder effect and an intrinsic genetic property of the virus. Here, we synthesized and expressed the WT and D614G variant SARS-Cov2 Spike protein, and report that using a SARS-CoV2 Spike protein pseudotyped lentiviral vector we observe that the D614G variant Spike has >1/2 log10 increased infectivity in human cells expressing the human ACE2 protein as the viral receptor. The increased binding/fusion activity of the D614G Spike protein was corroborated in a cell fusion assay using Spike and ACE2 proteins expressed in different cells. These results are consistent with the possibility that the Spike D614G mutant increases the infectivity of SARS-CoV2.

Performance of laboratory tests for detection for Clostridioides difficile: A multicenter prospective study in Japan.

BACKGROUND: The optimal and practical laboratory diagnostic approach for detection of Clostridioides difficile to aid in the diagnosis of C. difficile infection (CDI) is controversial. A two-step algorithm with initial detection of glutamate dehydrogenase (GDH) or nucleic acid amplification test (NAAT) alone are recommended as a predominant method for C. difficile detection in developed countries. The aim of this study was to compare the performance of enzyme immunoassays (EIA) detecting toxins A and B, NAAT detecting the toxin B gene, and GDH compared to toxigenic culture (TC) for C. difficile as the gold standard, in patients prospectively and actively assessed with clinically significant diarrhea in 12 medical facilities in Japan. METHODS: A total of 650 stool specimens were collected from 566 patients with at least three diarrheal bowel movements (Bristol stool grade 6-7) in the preceding 24 h. EIA and GDH were performed at each hospital, and NAAT and toxigenic C. difficile culture with enriched media were performed at the National Institute of Infectious Diseases. All C. difficile isolates recovered were analyzed by PCR-ribotyping. RESULTS: Compared to TC, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of EIA were 41%, 96%, 75% and 84%, respectively, and for NAAT were 74%, 98%, 91%, and 92%, respectively. In 439 specimens tested with GDH, the sensitivity, specificity, PPV, and NPV were 73%, 87%, 65%, and 91%, and for an algorithm (GDH plus toxin EIA, arbitrated by NAAT) were 71%, 96%, 85%, and 91%, respectively. Among 157 isolates recovered, 75% of isolates corresponded to one of PCR-ribotypes (RTs) 002, 014, 018/018", and 369; RT027 was not isolated. No clear differences in the sensitivities of any of EIA, NAAT and GDH for four predominant RTs were found. CONCLUSION: The analytical sensitivities of NAAT and GDH-algorithm to detect toxigenic C. difficile in this study were lower than most previous reports. This study also found low PPV of EIAs. The optimal method to detect C. difficile or its toxins to assist in the diagnosis of CDI needs further investigation.

Clostridioides (Clostridium) difficile infection burden in Japan: A multicenter prospective study.

Clostridioides (Clostridium) difficile is the leading cause of healthcare-associated infectious diarrhea in the developed world. Retrospective studies have shown a lower incidence of C. difficile infection (CDI) in Japan than in Europe or North America. Prospective studies are needed to determine if this is due lack of testing for C. difficile or a true difference in CDI epidemiology. A prospective cohort study of CDI was conducted from May 2014 to May 2015 at 12 medical facilities (20 wards) in Japan. Patients with at least three diarrheal bowel movements (Bristol stool grade 6-7) in the preceding 24 h were enrolled. CDI was defined by positive result on enzyme immunoassay for toxins A/B, nucleic acid amplification test for the toxin B gene or toxigenic culture. C. difficile isolates were subjected to PCR-ribotyping (RT), slpA-sequence typing (slpA-ST), and antimicrobial susceptibility testing. The overall incidence of CDI was 7.4/10,000 patient-days (PD). The incidence was highest in the five ICU wards (22.2 CDI/10,000 PD; range: 13.9-75.5/10,000 PD). The testing frequency and CDI incidence rate were highly correlated (R2 = 0.91). Of the 146 isolates, RT018/018″ was dominant (29%), followed by types 014 (23%), 002 (12%), and 369 (11%). Among the 15 non-ICU wards, two had high CDI incidence rates (13.0 and 15.9 CDI/10,000 PD), with clusters of RT018/slpA-ST smz-02 and 018"/smz-01, respectively. Three non-RT027 or 078 binary toxin-positive isolates were found. All RT018/018" isolates were resistant to moxifloxacin, gatifloxacin, clindamycin, and erythromycin. This study identified a higher CDI incidence in Japanese hospitals than previously reported by actively identifying and testing patients with clinically significant diarrhea. This suggests numerous patients with CDI are being overlooked due to inadequate diagnostic testing in Japan.

Glioblastoma Model Using Human Cerebral Organoids.

We have developed a cancer model of gliomas in human cerebral organoids that allows direct observation of tumor initiation as well as continuous microscopic observations. We used CRISPR/Cas9 technology to target an HRasG12V-IRES-tdTomato construct by homologous recombination into the TP53 locus. Results show that transformed cells rapidly become invasive and destroy surrounding organoid structures, overwhelming the entire organoid. Tumor cells in the organoids can be orthotopically xenografted into immunodeficient NOD/SCID IL2RG-/- animals, exhibiting an invasive phenotype. Organoid-generated putative tumor cells show gene expression profiles consistent with mesenchymal subtype human glioblastoma. We further demonstrate that human-organoid-derived tumor cell lines or primary human-patient-derived glioblastoma cell lines can be transplanted into human cerebral organoids to establish invasive tumor-like structures. Our results show potential for the use of organoids as a platform to test human cancer phenotypes that recapitulate key aspects of malignancy.

Psychosocial Strength Enhancing Resilience in Adolescents and Young Adults With Cancer.

The purpose of this study was to explore ways of enhancing psychosocial strengths in newly diagnosed and relapsed adolescents and young adults (AYAs) to improve their resilience. A descriptive case study was used. The adolescent resilience model (ARM) and the self-sustaining process model were applied as theories. The data were analyzed using pattern-matching logic. Semistructured interviews were conducted with 18 patients aged 12 to 24 years and discharged within 10 years. We found that the newly diagnosed and the relapsing AYAs developed the 5 strength factors of the ARM during and after treatment. Whether the individuals cultivated a positive attitude and sense of purpose early or late, the AYAs developed resilience eventually. A positive attitude and sense of purpose during the early phase of care may be essential for improving resilience. The AYAs benefited from the support of their parents, friends, and previous experience. Individualized support and social resources may be important to develop these strengths. Further research is needed to develop strengths and improve resilience in newly diagnosed AYAs.

Potentiation of insulin secretion and improvement of glucose intolerance by combining a novel G protein-coupled receptor 40 agonist DS-1558 with glucagon-like peptide-1 receptor agonists.

G protein-coupled receptor 40 (GPR40) is a Gq-coupled receptor for free fatty acids predominantly expressed in pancreatic ß-cells. In recent years, GPR40 agonists have been investigated for use as novel therapeutic agents in the treatment of type 2 diabetes. We discovered a novel small molecule GPR40 agonist, (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid (DS-1558). The GPR40-mediated effects of DS-1558 on glucose-stimulated insulin secretion were evaluated in isolated islets from GPR40 knock-out and wild-type (littermate) mice. The GPR40-mediated effects on glucose tolerance and insulin secretion were also confirmed by an oral glucose tolerance test in these mice. Furthermore, oral administration of DS-1558 (0.03, 0.1 and 0.3mg/kg) significantly and dose-dependently improved hyperglycemia and increased insulin secretion during the oral glucose tolerance test in Zucker fatty rats, the model of insulin resistance and glucose intolerance. Next, we examined the combination effects of DS-1558 with glucagon like peptide-1 (GLP-1). DS-1558 not only increased the glucose-stimulated insulin secretion by GLP-1 but also potentiated the maximum insulinogenic effects of GLP-1 after an intravenous glucose injection in normal Sprague Dawley rats. Furthermore, the glucose lowering effects of exendin-4, a GLP-1 receptor agonist, were markedly potentiated by the DS-1558 (3mg/kg) add-on in diabetic db/db mice during an intraperitoneal glucose tolerance test. In conclusion, our results indicate that add-on GPR40 agonists to GLP-1 related agents might be a potential treatment compared to single administration of these compounds. Therefore the combinations of these agents are a novel therapeutic option for type 2 diabetes.

Psychosocial factors influencing mental health in adults with congenital heart disease.

BACKGROUND: Although adult congenital heart disease (ACHD) patients encounter unique challenges related to social adaptation and mental health, only minimal research has been conducted on this functioning in Japanese ACHD patients. The aims of this study were to describe aspects of the psychosocial functioning of ACHD patients and to determine the psychosocial factors influencing their mental health. METHODS AND RESULTS: Seventy-two ACHD patients (aged 18-39 years) and 86 control participants (aged 18-39 years) completed the 36-item Short Form Health Survey, a measure of mental health, and 4 self-report questionnaires measuring aspects of psychosocial functioning: Independent-Consciousness, Problem-solving, Locus of Control, and Self-esteem. Compared to the control group, ACHD patients had significantly lower scores for Independence, Problem-solving, and Self-esteem; whereas they had higher scores for Dependence on Parents. To examine the psychosocial factors influencing mental health, a structural equation model was used. The psychosocial factor Problem-solving was found to have the most direct influence on mental health. This factor was associated with Independence and Self-esteem. CONCLUSIONS: ACHD patients in Japan have psychosocial difficulties, and the psychosocial factors influencing patients' mental health are social problem-solving, independence, and self-esteem. The patients have poorer abilities than the control group in all of these areas and hence, they run the risk of developing poor mental health.

Corneal and retinal effects of ultraviolet-B exposure in a soft contact lens mouse model.

PURPOSE: To investigate the lipid and DNA oxidative stress as well as corneal and retinal effects after ultraviolet B (UV-B) exposure in mice, with or without silicon hydrogel soft contact lenses (SCL). METHODS: Twenty-eight C57BL6-strain male mice were divided into four groups: group I, control group with no SCL (SCL [-]) and no UV-B exposure (UV-B [-]); group II, senofilcon A SCL (senofilcon [+]) with UV-B exposure (UV-B [+]); group III, lotrafilcon A SCL (lotrafilcon [+]) with UV-B exposure (UV-B [+]); and group IV, no SCL (SCL [-]), but with UV-B exposure (UV-B [+]). All mice except group I received UV-B exposure for 5 days for a total dose of 2.73 J/cm(2). All mice underwent tear hexanoyl-lysine (HEL) and tear cytokine ELISA measurements, and fluorescein and rose bengal corneal staining before and after UV-B exposure. Corneal specimens underwent immunohistochemistry staining with CD45, HEL, 4-hydroxynonenal (4-HNE), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) antibodies and evaluation with electron microscopy. RESULTS: All mice without SCL but exposed to UV-B developed corneal edema, ulcers, or epithelial damage compared with mice with senofilcon A SCL and exposure to UV-B. Tear HEL and cytokine levels significantly increased in mice without SCL after UV-B exposure. Immunohistochemistry showed a significantly higher number of cells positively stained for CD45, 8-OHdG, HEL, and 4-HNE in the corneas of mice without SCLs compared with those with senofilcon A after UV-B exposure. CONCLUSION: Silicon hydrogel SCL showed corneal and retinal protective effects, owing to UV blocking properties, against oxidative stress-related membrane lipid and cellular DNA damage.

Morphological features of mutant rat, IS-Tlk/Kyo, fetuses with caudal vertebral anomalies.

IS-Tlk/Kyo, a rat mutant strain derived from IS/Kyo strain, exhibits a kinked and/or short tail, in addition to a congenital anomaly of the lumbar vertebrae that is a hallmark of IS/Kyo rats. Homozygotes (Tlk/Tlk) of Tlk dominant gene are known to die during embryonic development. The present report deals with the morphological features of heterozygous IS-Tlk/Kyo rat fetuses in comparison with those of IS/Kyo rat fetuses. One of the morphological features was a high incidence of tail vertebral anomalies in IS-Tlk rats (81.6% versus 0% in IS/Kyo rats). Significantly low values in number of live fetuses and ossified 5th sternebra and sacral and caudal vertebrae were observed in IS-Tlk/Kyo rats compared with those in IS/Kyo rats as well as a low incidence of fetuses with ventral septal defects in IS-Tlk/Kyo (0% versus 54.4% in IS rats). These results suggest that the Tlk gene may be involved in the formation of the vertebral centra and the ventral septum when it expresses on the genetic background of the IS rat.

Laminin α1 is essential for mouse cerebellar development.

Laminin α1 (Lama1), which is a subunit of laminin-1 (laminin-111), a heterotrimeric ECM protein, is essential for embryonic development and promotes neurite outgrowth in culture. Because the deletion of Lama1 causes lethality at early embryonic stages in mice, the in vivo role of Lama1 in neural development and functions has not yet been possible to determine. In this study, we generated conditional Lama1 knockout (Lama1(CKO)) mice in the epiblast lineage using Sox2-Cre mice. These Lama1(CKO) mice survived, but displayed behavioral disorders and impaired formation of the cerebellum. Deficiency of Lama1 in the pial basement membrane of the meninges resulted in defects in the conformation of the meninges. During cerebellar development, Lama1 deficiency also caused a decrease in the proliferation and migration of granule cell precursors, disorganization of Bergmann glial fibers and endfeet, and a transient reduction in the activity of Akt. A marked reduction in numbers of dendritic processes in Purkinje cells was observed in Lama1(CKO) mice. Together, these results indicate that Lama1 is required for cerebellar development and functions.

Effect of controlled adverse chamber environment exposure on tear functions in silicon hydrogel and hydrogel soft contact lens wearers.

PURPOSE: To prospectively evaluate the effect of controlled adverse chamber environment (CACE) exposure on tear function, including tear osmolarity, in subjects wearing narafilcon A versus those wearing etafilcon A soft contact lens (SCL). METHODS: Thirty-one healthy subjects with no history of contact lens wear (13 women, 18 men; average age, 30.5 ± 6.5 years) were randomly divided into age- and sex-matched groups (15 subjects wearing narafilcon A SCL; 16 subjects wearing etafilcon A SCL) and entered a CACE for 20 minutes. All subjects underwent tear osmolarity, tear evaporation rate, strip meniscometry, tear film breakup time, fluorescein vital staining, and functional visual acuity measurement before and after exposure to the controlled adverse chamber. RESULTS: The mean blink rate increased with significant deteriorations in the mean symptom VAS scores, mean tear osmolarity, tear evaporation rate, strip meniscometry score, and tear stability with CACE exposure along with a decrease in visual maintenance ratio in functional visual acuity testing in etafilcon A wearers. The mean symptom VAS scores, mean tear evaporation rate, tear stability, blink rates, and visual maintenance ratios did not change significantly in narafilcon A wearers after CACE exposure. CONCLUSIONS: This study suggested marked tear instability, higher tear osmolarity, and increased tear evaporation with marked dry eye and visual symptomatology in nonadapted hydrogel SCL wearers, suggesting that silicone hydrogel SCLs may be suitable for persons who live and work in cool, low-humidity, and windy environments, as tested in this study.

The impact of contact lens wear and visual display terminal work on ocular surface and tear functions in office workers.

PURPOSE: To evaluate the effect of contact lens (CL) wear and visual display terminal (VDT) work on the ocular surface and tear functions. DESIGN: Prospective case-control study. METHODS: Sixty-nine CL wearers (45 women and 24 men; mean age, 35.2 ± 7.3 years), and 102 age- and sex-matched non-CL wearers were enrolled in the study (66 women and 36 men; mean age, 36.7 ± 7.3 years). Ocular surface and tear function tests, including vital stainings (fluorescein and rose bengal), Schirmer test, tear meniscus height measurement, and tear film break-up time were performed. The subjective symptoms of dry eyes were evaluated using a dry eye symptom questionnaire. The participants were divided into 4 subgroups according to the total time of VDT work in 1 day (VDT work time in 1 day ≥ 4 hours or < 4 hours) and presence of CL wear. Main outcome measures included ocular surface vital staining scores, Schirmer test results, tear film break-up time, tear meniscus height measurement, and symptom questionnaire score. RESULTS: CL users and long-term VDT workers showed significantly worse tear meniscus height values than non-CL users and short-term VDT workers (P < .001). The mean visual symptom scores in CL wearers and long-term VDT workers were significantly higher than the other groups (P < .001). CONCLUSIONS: Office workers who wore CLs and spent more than 4 hours engaged in VDT work had a lower tear meniscus volume with significant dry eye and visual symptoms triggered by environmental factors.

Contributions of hepatic gluconeogenesis suppression and compensative glycogenolysis on the glucose-lowering effect of CS-917, a fructose 1,6-bisphosphatase inhibitor, in non-obese type 2 diabetes Goto-Kakizaki rats.

Contributions of gluconeogenesis suppression in liver, kidney, and intestine as major gluconeogenic organs to the glucose-lowering effect of CS-917, a fructose 1,6-bisphosphatase inhibitor, was evaluated in overnight-fasted Goto-Kakizaki (GK) rats. CS-917 decreased plasma glucose by suppressing glucose release and lactate uptake from liver but not from kidney and intestine. These results suggest that hepatic gluconeogenesis suppression predominantly contributes to the glucose-lowering effect of CS-917 in GK rats. Moreover, the mechanism by which CS-917 decreased plasma glucose more in overnight-fasted GK rats than in non-fasted ones was investigated. Lactate uptake from liver was suppressed by 15 mg/kg of CS-917 in both states, but glucose release from liver and plasma glucose were decreased only in the overnight-fasted state. CS-917 at 30 mg/kg decreased hepatic glycogen content in both states and depleted it in the overnight-fasted state. In the non-fasted GK rats, co-administration of CS-917 with CP-91149, a glycogen phosphorylase inhibitor, suppressed hepatic glycogen reduction by CS-917 and decreased plasma glucose more than single administration of CS-917. These results suggest that gluconeogenesis suppression by CS-917 was counteracted by hepatic glycogenolysis especially in the non-fasted state and that combination therapy with CS-917 and CP-91149 is efficacious to decrease plasma glucose in GK rats.

The effects of 2 week senofilcon-A silicone hydrogel contact lens daily wear on tear functions and ocular surface health status.

PURPOSE: To prospectively investigate the effects of 2 week senofilcon A contact lens (CL) daily wear on the functional visual acuity (VA), ocular surface and tear film. METHODS: Seventeen right eyes of 17 senofilcon A CL wearers without any ocular or systemic diseases were examined before and 2 weeks after lens wear. Visual acuity measurements, tear evaporation rate, ELISA for tear cytokines, strip meniscometry, tear lipid layer interferometry, tear film break-up time (BUT), in vivo confocal microscopy, corneal sensitivity, ocular surface vital staining, Schirmer I test and brush cytology for MUC5AC mRNA expression were performed before and after CL wear. RESULTS: The best corrected Landolt VA, functional VA parameters, the mean lipid layer interferometry grades, tear evaporation rates, Schirmer test values, vital staining scores and in vivo confocal microscopy parameters did not show any significant differences after 2 weeks of CL wear. The tear film BUT showed a significant decrease together with a significant down regulation of MUC5 AC mRNA expression after CL wear. A statistically significant elevation in the mean tear interleukin (IL)-6 concentration was also observed after 2 weeks of CL wear. CONCLUSIONS: Two week senofilcon A daily CL wear seems to be associated with tear instability, a decrease in MUC5AC expression, and elevation of IL-6 in tears without significant alterations in epithelial damage scores or in the morphology or density of in vivo keratoconjunctival cells and nerves. Alterations associated with long term wear and patients with dry eye disease need to be studied in future trials.

Roles of heparan sulfate in mammalian brain development current views based on the findings from Ext1 conditional knockout studies.

Development of the mammalian central nervous system proceeds roughly in four major steps, namely the patterning of the neural tube, generation of neurons from neural stem cells and their migration to genetically predetermined destinations, extension of axons and dendrites toward target neurons to form neural circuits, and formation of synaptic contacts. Earlier studies on spatiotemporal expression patterns and in vitro function of heparan sulfate (HS) suggested that HS is functionally involved in various aspects of neural development. Recent studies using knockout of genes involved in HS biosynthesis have provided more physiologically relevant information as to the role of HS in mammalian neural development. This chapter reviews the current understanding of the in vivo function of HS deduced from the phenotypes of conditional Ext1 knockout mice.

Passive cigarette smoke exposure and soft contact lens wear.

PURPOSE: To prospectively investigate the effects of passive cigarette smoke exposure on the ocular surface and tear film in soft contact lens (SCL) wearers. METHODS: Twelve right eyes of 12 SCL wearers without any ocular or systemic diseases and 10 right eyes of 10 subjects who never wore CLs were examined before and 2 h after 5 min of passive cigarette smoke exposure in a controlled smoke chamber. Tear evaporation rate measurement, tear film break-up time (TBUT) examination, ocular surface fluorescein, rose bengal stainings, and Schirmer I test were performed at each visit. RESULTS: The mean tear evaporation rates, TBUTs, and vital staining scores were significantly worse in CL wearers compared with healthy control subjects. TBUTs showed significant worsening after passive smoke exposure in both groups. The mean tear evaporation rate and vital staining scores showed a significant increase with brief passive smoke exposure in subjects not wearing CLs but not in CL wearers. CONCLUSION: Even brief passive exposure to cigarette smoke is associated with adverse effects on the ocular surface as evidenced by an increase in tear instability and damage to the ocular surface epithelia in SCL wearers and non-CL wearers.

Potent antidiabetic effects of rivoglitazone, a novel peroxisome proliferator-activated receptor-gamma agonist, in obese diabetic rodent models.

The pharmacological effects of rivoglitazone, a novel thiazolidinedione-derivative peroxisome proliferator-activated receptor (PPAR)-gamma agonist, were characterized in vitro and in vivo. Rivoglitazone activated human PPARgamma more potently compared with rosiglitazone and pioglitazone and had little effect on PPARalpha and PPARdelta activity in luciferase reporter assays. In Zucker diabetic fatty (ZDF) rats, 14-day administration of rivoglitazone decreased the plasma glucose and triglyceride (TG) levels in a dose-dependent manner. The glucose-lowering effect of rivoglitazone was much more potent than those of pioglitazone (ED(50): 0.19 vs. 34 mg/kg) and rosiglitazone (ED(50): 0.20 vs. 28 mg/kg). In addition, rivoglitazone showed potent antidiabetic effects in diabetic db/db mice. In Zucker fatty rats, rivoglitazone at a dose of 0.1 mg/kg clearly ameliorated insulin resistance and lowered plasma TG levels by accelerating the clearance of plasma TG. Gene expression analysis in the liver and heart of ZDF rats treated with rivoglitazone for 14 days suggested that rivoglitazone may reduce hepatic glucose production and modulate the balance of the cardiac glucose/fatty acid metabolism in diabetic animals. In summary, we showed that rivoglitazone is a potent and selective PPARgamma agonist and has a potent glucose-lowering effect via improvement of the insulin resistance in diabetic animal models.

Metformin primarily decreases plasma glucose not by gluconeogenesis suppression but by activating glucose utilization in a non-obese type 2 diabetes Goto-Kakizaki rats.

Metformin is an anti-diabetic agent that has been reported to decrease plasma glucose by multiple mechanisms, such as decreasing hepatic glucose production and activating peripheral glucose utilization. In order to elucidate the primary glucose-lowering mechanism of metformin, the present study focused on a comparison of the acute effect between metformin and CS-917 as a direct gluconeogenesis inhibitor. We examined the effect of metformin and CS-917 on glucose turnover in intravenous glucose-loaded Goto-Kakizaki (GK) rats, and on gluconeogenesis and glucose utilization in rat hepatocytes. Moreover, the glucose-lowering effect of metformin and CS-917 was compared in a fed and a fasted state in GK rats. In intravenous glucose-loaded GK rats, metformin and CS-917 lowered plasma glucose by increasing the glucose disappearance rate and by decreasing the glucose appearance rate, respectively. In rat hepatocytes, CS-917 but not metformin suppressed gluconeogenesis (IC(50)=0.136microM). Instead, metformin dose-dependently increased glucose uptake and the following lactate production at 30 to 100microM. Metformin decreased plasma glucose more in a fed state than in a fasted state in GK rats. CS-917, however, decreased plasma glucose more in a fasted state. These results confirm that metformin primarily decreases plasma glucose not by gluconeogenesis inhibition but by activating glucose utilization in GK rats. Moreover, metformin and CS-917 have different glucose-lowering effects depending on the nutrient state, which may be related to differences in their mechanisms of action. Such differences in action may have implications for metformin and CS-917 in the treatment of type 2 diabetes patients.