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1.
Vox Sang ; 113(2): 128-135, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29067694

ABSTRACT

BACKGROUND AND OBJECTIVES: Adverse reactions to platelet transfusions are a problem. Children with primary haematological and malignant diseases may experience allergic transfusion reactions (ATRs) to platelet concentrates (PCs), which can be prevented by giving washed PCs. A new platelet additive solution, using bicarbonated Ringer's solution and acid-citrate-dextrose formula A (BRS-A), may be better for platelet washing and storage, but clinical data are scarce. MATERIALS AND METHODS: A retrospective cohort study for consecutive cases was performed between 2013 and 2017. For 24 months, we transfused washed PCs containing BRS-A to children with primary haematological and malignant diseases and previous adverse reactions. Patients transfused with conventional PCs (containing residual plasma) were assigned as controls, and results were compared in terms of frequency of ATRs, corrected count increment (CCI) and occurrence of bleeding. We also studied children transfused with PCs washed by a different system as historical controls. RESULTS: Thirty-two patients received 377 conventional PC transfusions. ATRs occurred in 12 (37·5%) patients from transfused with 18 (4·8%) bags. Thirteen patients, who experienced reactions to regular PCs in plasma, then received 119 transfusion bags of washed PCs containing BRS-A, and none had ATRs to washed PCs containing BRS-A. Before study period, six patients transfused 137 classical washed PCs with different platelet additive solution, under same indication, ATRs occurred in one (16·7%) patient from transfused with one (0·7%) bags. CCIs (24 h) in were lower with classical washed PCs (1·26 ± 0·54) compared to regular PCs in plasma (2·07 ± 0·76) (P < 0·001), but there was no difference between washed PCs containing BRS-A (2·14 ± 0·77) and regular PCs (2·21 ± 0·79) (P = 0·769), and we saw no post-transfusion bleeding. CONCLUSION: Washed PCs containing BRS-A appear to prevent ATRs without loss of transfusion efficacy in children with primary haematological and malignant diseases. Their efficacy should be further evaluated through larger prospective clinical trials.


Subject(s)
Blood Platelets/immunology , Platelet Transfusion/methods , Transfusion Reaction/prevention & control , Blood Platelets/drug effects , Child , Female , Humans , Isotonic Solutions/pharmacology , Male , Platelet Transfusion/adverse effects , Transfusion Reaction/immunology
3.
Acta Neurol Scand ; 135(2): 252-256, 2017 Feb.
Article in English | MEDLINE | ID: mdl-26923256

ABSTRACT

BACKGROUND: Ethnic diversity between different populations may affect treatment safety and efficacy. AIMS AND METHODS: A subanalysis to a global trial (study 326) was carried out to ascertain the safety and efficacy of donepezil 23 mg/day compared with donepezil 10 mg/day in Asian patients with moderate-to-severe Alzheimer's disease. Changes in cognition and global functioning were measured by the Severe Impairment Battery (SIB) and Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus), respectively, at week 24. RESULTS: Cognitive improvement measured by SIB score was greater with donepezil 23 mg than with donepezil 10 mg (+1.36 vs -1.56]; difference, 2.92). There was no difference between the groups in global function measured by the CIBIC-Plus (3.94 and 3.95, respectively). Overall, 119 patients (82.1%) receiving donepezil 23 mg and 56 (71.8%) receiving donepezil 10 mg experienced ≥1 treatment emergent adverse events (TEAEs). In the donepezil 23 mg group, the incidence of TEAEs was higher among patients of lower weight (<55 kg) at baseline than in those of higher weight (64 of 75 patients [85.3%] vs 55 of 70 patients [78.5%]). CONCLUSIONS: The benefits and risks associated with donepezil 23 mg in Asian patients are comparable to those of the global study population.


Subject(s)
Alzheimer Disease/diagnosis , Alzheimer Disease/drug therapy , Asian People , Cholinesterase Inhibitors/therapeutic use , Indans/therapeutic use , Piperidines/therapeutic use , Severity of Illness Index , Aged , Aged, 80 and over , Alzheimer Disease/epidemiology , Cholinesterase Inhibitors/adverse effects , Donepezil , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Indans/adverse effects , Male , Middle Aged , Nausea/chemically induced , Piperidines/adverse effects , Treatment Outcome
5.
Diabetologia ; 55(6): 1745-54, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22456697

ABSTRACT

AIMS/HYPOTHESIS: We investigated changes in the expression of genes involved in beta cell function and proliferation in mouse islets stimulated with glucokinase activator (GKA) in order to elucidate the mechanisms by which GKA stimulates beta cell function and proliferation. METHODS: Islets isolated from mice were used to investigate changes in the expression of genes related to beta cell function and proliferation stimulated by GKA. In addition, Irs2 knockout (Irs2 (-/-)) mice on a high-fat diet or a high-fat diet containing GKA were used to investigate the effects of GKA on beta cell proliferation in vivo. RESULTS: In wild-type mice, Irs2 and Pdx1 expression was increased by GKA. In Irs2 (-/-) mice, GKA administration increased the glucose-stimulated secretion of insulin and Pdx1 expression, but not beta cell proliferation. It was particularly noteworthy that oxidative stress inhibited the upregulation of the Irs2 and Pdx1 genes induced by GKA. Moreover, whereas neither GKA alone nor exendin-4 alone upregulated the expression of Irs2 and Pdx1 in the islets of db/db mice, prior administration of exendin-4 to the mice caused GKA to increase the expression of these genes. CONCLUSIONS/INTERPRETATION: GKA-stimulated IRS2 production affected beta cell proliferation but not beta cell function. Oxidative stress diminished the effects of GKA on the changes in expression of genes involved in beta cell function and proliferation. A combination of GKA and an incretin-related agent might therefore be effective in therapy.


Subject(s)
Cell Proliferation/drug effects , Enzyme Activators/pharmacology , Glucokinase/metabolism , Insulin-Secreting Cells/cytology , Insulin-Secreting Cells/drug effects , Animals , Blotting, Western , Immunohistochemistry , Insulin Receptor Substrate Proteins , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Mice , Mice, Knockout , Oxidative Stress/drug effects , Oxidative Stress/genetics
6.
Diabetologia ; 55(12): 3382-91, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22955994

ABSTRACT

AIMS/HYPOTHESIS: Epidemiological studies have revealed that obesity and diabetes mellitus are independent risk factors for the development of non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma. However, the debate continues on whether insulin resistance as such is directly associated with NASH and liver tumourigenesis. Here, we investigated the incidence of NASH and liver tumourigenesis in Irs1 ( -/- ) mice subjected to a long-term high-fat (HF) diet. Our hypothesis was that hepatic steatosis, rather than insulin resistance may be related to the pathophysiology of these conditions. METHODS: Mice (8 weeks old, C57Bl/6J) were given free access to standard chow (SC) or an HF diet. The development of NASH and liver tumourigenesis was evaluated after mice had been on the above-mentioned diets for 60 weeks. Similarly, Irs1 ( -/- ) mice were also subjected to an HF diet for 60 weeks. RESULTS: Long-term HF diet loading, which causes obesity and insulin resistance, was sufficient to induce NASH and liver tumourigenesis in the C57Bl/6J mice. Obesity and insulin resistance were reduced by switching mice from the HF diet to SC, which also protected these mice against the development of NASH and liver tumourigenesis. However, compared with wild-type mice fed the HF diet, Irs1 ( -/- ) mice fed the HF diet were dramatically protected against NASH and liver tumourigenesis despite the presence of severe insulin resistance and marked postprandial hyperglycaemia. CONCLUSIONS/INTERPRETATION: IRS-1 inhibition might protect against HF diet-induced NASH and liver tumourigenesis, despite the presence of insulin resistance.


Subject(s)
Carcinoma, Hepatocellular/pathology , Diabetes Mellitus, Experimental/pathology , Fatty Liver/pathology , Insulin Receptor Substrate Proteins/metabolism , Liver Neoplasms/pathology , Liver/pathology , Animals , Carcinoma, Hepatocellular/blood , Diabetes Mellitus, Experimental/blood , Diet, High-Fat , Disease Models, Animal , Disease Progression , Fatty Liver/blood , Glucose Tolerance Test , Insulin Receptor Substrate Proteins/genetics , Insulin Resistance , Liver Neoplasms/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Non-alcoholic Fatty Liver Disease , Obesity/pathology
7.
Diabetologia ; 55(12): 3318-30, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22983607

ABSTRACT

AIMS/HYPOTHESIS: Insufficient insulin secretion and reduced pancreatic beta cell mass are hallmarks of type 2 diabetes. Here, we focused on a family of serine-threonine kinases known as homeodomain-interacting protein kinases (HIPKs). HIPKs are implicated in the modulation of Wnt signalling, which plays a crucial role in transcriptional activity, and in pancreas development and maintenance. The aim of the present study was to characterise the role of HIPKs in glucose metabolism. METHODS: We used RNA interference to characterise the role of HIPKs in regulating insulin secretion and transcription activity. We conducted RT-PCR and western blot analyses to analyse the expression and abundance of HIPK genes and proteins in the islets of high-fat diet-fed mice. Glucose-induced insulin secretion and beta cell proliferation were measured in islets from Hipk3 ( -/- ) mice, which have impaired glucose tolerance owing to an insulin secretion deficiency. The abundance of pancreatic duodenal homeobox (PDX)-1 and glycogen synthase kinase (GSK)-3ß phosphorylation in Hipk3 ( -/- ) islets was determined by immunohistology and western blot analyses. RESULTS: We found that HIPKs regulate insulin secretion and transcription activity. Hipk3 expression was most significantly increased in the islets of high-fat diet-fed mice. Furthermore, glucose-induced insulin secretion and beta cell proliferation were decreased in the islets of Hipk3 ( -/- ) mice. Levels of PDX1 and GSK-3ß phosphorylation were significantly decreased in Hipk3 ( -/- ) islets. CONCLUSIONS/INTERPRETATION: Depletion of HIPK3 impairs insulin secretion and glucose tolerance. Decreased levels of HIPK3 may play a substantial role in the pathogenesis of type 2 diabetes.


Subject(s)
Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 2/metabolism , Homeodomain Proteins/metabolism , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Animals , Cells, Cultured , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Type 2/pathology , Diet, High-Fat , Female , Glucose Tolerance Test , Insulin Secretion , Insulin-Secreting Cells/pathology , Male , Mice , Mice, Knockout , Pancreas/metabolism , RNA Interference
8.
Surg Case Rep ; 8(1): 220, 2022 Dec 09.
Article in English | MEDLINE | ID: mdl-36484868

ABSTRACT

BACKGROUND: Follicular dendritic cell sarcoma is a rare stromal tumor with no standard treatment. However, some reports have revealed that follicular dendritic cell sarcoma has an inflammatory pseudotumor variant associated with Epstein-Barr virus infection that has a relatively good prognosis. In this report, we present a case of a resected inflammatory pseudotumor variant of follicular dendritic cell sarcoma of the liver, and have reviewed the literature on the clinicopathological, molecular, and genomic features of this tumor. CASE PRESENTATION: The inflammatory pseudotumor variant of follicular dendritic cell sarcoma originates only in the liver or spleen, causes no symptoms, and is more common in middle-aged Asian women. It has no characteristic imaging features, which partially explains why the inflammatory pseudotumor variant of follicular dendritic cell sarcoma is difficult to diagnose. Pathologically, the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has spindle cells mixed with inflammatory cells and is variably positive for follicular dendritic cell markers (CD21, CD23, and CD35) and Epstein-Barr virus-encoded RNA. On genetic analysis, patients with this tumor high levels of latent membrane protein 1 gene expression and extremely low levels of host C-X-C Chemokine Receptor type 7 gene expression, indicating that the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has a latent Epstein-Barr virus type 2 infection. CONCLUSIONS: The inflammatory pseudotumor variant of follicular dendritic cell sarcoma is an Epstein-Barr virus-associated tumor and a favorable prognosis by surgical resection, similar to Epstein-Barr virus-associated gastric cancer.

9.
Nat Med ; 7(8): 941-6, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11479627

ABSTRACT

Adiponectin is an adipocyte-derived hormone. Recent genome-wide scans have mapped a susceptibility locus for type 2 diabetes and metabolic syndrome to chromosome 3q27, where the gene encoding adiponectin is located. Here we show that decreased expression of adiponectin correlates with insulin resistance in mouse models of altered insulin sensitivity. Adiponectin decreases insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. This effect results from increased expression of molecules involved in both fatty-acid combustion and energy dissipation in muscle. Moreover, insulin resistance in lipoatrophic mice was completely reversed by the combination of physiological doses of adiponectin and leptin, but only partially by either adiponectin or leptin alone. We conclude that decreased adiponectin is implicated in the development of insulin resistance in mouse models of both obesity and lipoatrophy. These data also indicate that the replenishment of adiponectin might provide a novel treatment modality for insulin resistance and type 2 diabetes.


Subject(s)
Adipose Tissue/physiopathology , Insulin Resistance , Intercellular Signaling Peptides and Proteins , Obesity/physiopathology , Proteins/physiology , Adiponectin , Adipose Tissue/metabolism , Amino Acid Sequence , Animals , Leptin/metabolism , Mice , Molecular Sequence Data , Oxidation-Reduction , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/physiology , Signal Transduction , Transcription Factors/genetics , Transcription Factors/physiology , Triglycerides/metabolism
10.
Eur J Med Res ; 16(12): 537-42, 2011 Dec 02.
Article in English | MEDLINE | ID: mdl-22112360

ABSTRACT

BACKGROUND: Burkholderia cepacia strains have been known to possess the capability to cause serious infections especially in neonatal intensive care units (NICUs), and their multi-drug resistances become a severe threat in hospital settings. The aim of this investigation was to evaluate the B. cepacia complex infections in the NICU in Nagano Children's Hospital, Azumino 399-8288, Japan, and to report the intervention leading to the successful cessation of the outbreak. METHODOLOGY: The incidence of isolation and antimicrobial susceptibilities of nosocomial Burkholderia cepacia complex strains during a four-year period were retrospectively examined by clinical microbiological records, and by pulsed-field gel electrophoresis analyses along with the bacteriological verification of disinfectant device itself and procedures for its maintenance routinely used in the NICU. RESULTS: During the period surveyed between 2007 and 2009, only an isolate per respective year of B. cepacia complex was recovered from each neonate in the NICU. However, in 2010, the successive 6 B. cepacia complex isolates were recovered from different hospitalized neonates. Among them, an isolate was originated from peripheral blood of a neonate, apparently giving rise to systemic infection. In addition, the hospitalized neonate with bacteremia due to B. cepacia complex also exhibited positive cultures from repeated catheterized urine samples together with tracheal aspirate secretions. However other 5 isolates were considered as the transients or contaminants having little to do with infections. Moreover, the 5 isolates between July and October in 2010 revealed completely the same electrophoresis patterns by means of pulsed-field gel electrophoresis analyses, strongly indicating that they were infected through the same medical practices, or by transmission of the same contaminant. CONCLUSIONS: A small outbreak due to B. cepacia comlex was brought about in the NICU in 2010, which appeared to be associated with the same genomovar of B. cepacia complex. The source or the rout of infection was unknown in spite of the repeated epidemiological investigation. It is noteworthy that no outbreak due to B. cepacia complex was noted in the NICU after extensive surveillance intervention.


Subject(s)
Burkholderia Infections/epidemiology , Burkholderia Infections/transmission , Burkholderia cepacia complex/pathogenicity , Cross Infection/transmission , Infection Control/methods , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Burkholderia Infections/drug therapy , Burkholderia cepacia complex/drug effects , Burkholderia cepacia complex/isolation & purification , Cross Infection/epidemiology , Disease Outbreaks , Electrophoresis, Gel, Pulsed-Field , Hospitals, Pediatric , Humans , Infant , Infant, Newborn , Intensive Care Units, Neonatal , Japan , Retrospective Studies
11.
J Prev Alzheimers Dis ; 8(1): 7-18, 2021.
Article in English | MEDLINE | ID: mdl-33336219

ABSTRACT

BACKGROUND: Irregular sleep-wake rhythm disorder (ISWRD) is a common sleep disorder in individuals with Alzheimer's disease dementia (AD-D). OBJECTIVES: This exploratory phase 2 proof-of-concept and dose-finding clinical trial evaluated the effects of lemborexant compared with placebo on circadian rhythm parameters, nighttime sleep, daytime wakefulness and other clinical measures of ISWRD in individuals with ISWRD and mild to moderate AD-D. DESIGN: Multicenter, randomized, double-blind, placebo-controlled, parallel-group study. SETTING: Sites in the United States, Japan and the United Kingdom. PARTICIPANTS: Men and women 60 to 90 years of age with documentation of diagnosis with AD-D and Mini-Mental State Exam (MMSE) score 10 to 26. INTERVENTION: Subjects were randomized to placebo or one of four lemborexant treatment arms (2.5 mg, 5 mg, 10 mg or 15 mg) once nightly at bedtime for 4 weeks. MEASUREMENTS: An actigraph was used to collect subject rest-activity data, which were used to calculate sleep-related, wake-related and circadian rhythm-related parameters. These parameters included least active 5 hours (L5), relative amplitude of the rest-activity rhythm (RA) and mean duration of sleep bouts (MDSB) during the daytime. The MMSE and the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) were used to assess for changes in cognitive function. RESULTS: Sixty-two subjects were randomized and provided data for circadian, daytime and nighttime parameters (placebo, n = 12; lemborexant 2.5 mg [LEM2.5], n = 12; lemborexant 5 mg [LEM5], n = 13, lemborexant 10 mg [LEM10], n = 13 and lemborexant 15 mg [LEM15], n = 12). Mean L5 showed a decrease from baseline to week 4 for LEM2.5, LEM5 and LEM15 that was significantly greater than with placebo (all p < 0.05), suggesting a reduction in restlessness. For RA, LS mean change from baseline to week 4 versus placebo indicated greater distinction between night and day with all dose levels of lemborexant, with significant improvements seen with LEM5 and LEM15 compared with placebo (both p < 0.05). The median percentage change from baseline to week 4 in MDSB during the daytime indicated a numerical decrease in duration for LEM5, LEM10 and LEM15, which was significantly different from placebo for LEM5 and LEM15 (p < 0.01 and p = 0.002, respectively). There were no serious treatment-emergent adverse events or worsening of cognitive function, as assessed by the MMSE and ADAS-Cog. Lemborexant was well tolerated. No subjects discontinued treatment. CONCLUSIONS: This study provides preliminary evidence of the potential utility of lemborexant as a treatment to address both nighttime and daytime symptoms in patients with ISWRD and AD-D.


Subject(s)
Alzheimer Disease/complications , Circadian Rhythm/drug effects , Orexin Receptor Antagonists/administration & dosage , Pyridines/administration & dosage , Pyrimidines/administration & dosage , Sleep Wake Disorders/drug therapy , Actigraphy/methods , Aged , Aged, 80 and over , Double-Blind Method , Female , Humans , Male , Middle Aged , Orexin Receptor Antagonists/pharmacology , Pyridines/pharmacology , Pyrimidines/pharmacology , Sleep Wake Disorders/etiology
12.
Science ; 283(5404): 981-5, 1999 Feb 12.
Article in English | MEDLINE | ID: mdl-9974390

ABSTRACT

Glucose metabolism in glycolysis and in mitochondria is pivotal to glucose-induced insulin secretion from pancreatic beta cells. One or more factors derived from glycolysis other than pyruvate appear to be required for the generation of mitochondrial signals that lead to insulin secretion. The electrons of the glycolysis-derived reduced form of nicotinamide adenine dinucleotide (NADH) are transferred to mitochondria through the NADH shuttle system. By abolishing the NADH shuttle function, glucose-induced increases in NADH autofluorescence, mitochondrial membrane potential, and adenosine triphosphate content were reduced and glucose-induced insulin secretion was abrogated. The NADH shuttle evidently couples glycolysis with activation of mitochondrial energy metabolism to trigger insulin secretion.


Subject(s)
Glucose/pharmacology , Insulin/metabolism , Islets of Langerhans/metabolism , Mitochondria/metabolism , NAD/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Aminooxyacetic Acid/pharmacology , Animals , Aspartate Aminotransferases/antagonists & inhibitors , Calcium/metabolism , Citric Acid Cycle , Enzyme Inhibitors/pharmacology , Female , Gene Targeting , Glucose/metabolism , Glycerolphosphate Dehydrogenase/genetics , Glycerolphosphate Dehydrogenase/metabolism , Glycolysis , Insulin Secretion , Male , Membrane Potentials , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Models, Biological , Molecular Sequence Data , Pyruvic Acid/metabolism
13.
Gut ; 57(11): 1531-8, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18676419

ABSTRACT

BACKGROUND AND AIMS: The effect of adiponectin on colorectal carcinogenesis has been proposed but not fully investigated. We investigated the effect of adiponectin deficiency on the development of colorectal cancer. METHODS: We generated three types of gene-deficient mice (adiponectin-deficient, adiponectin receptor 1-deficient, and adiponectin receptor 2-deficient) and investigated chemical-induced colon polyp formation and cell proliferation in colon epithelium. Western blot analysis was performed to elucidate the mechanism which affected colorectal carcinogenesis by adiponectin deficiency. RESULTS: The numbers of colon polyps were significantly increased in adiponectin-deficient mice compared with wild-type mice fed a high-fat diet. However, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. A significant increase in cell proliferative activity was also observed in the colonic epithelium of the adiponectin-deficient mice when compared with wild-type mice fed a high-fat diet; however, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. Similarly, an increase in epithelial cell proliferation was observed in adiponectin receptor 1-deficient mice, but not in adiponectin receptor 2-deficient mice. Western blot analysis revealed activation of mammalian target of rapamycin, p70 S6 kinase, S6 protein and inactivation of AMP-activated protein kinase in the colon epithelium of adiponectin-deficient mice fed with high-fat diet. CONCLUSIONS: Adiponectin suppresses colonic epithelial proliferation via inhibition of the mammalian target of the rapamycin pathway under a high-fat diet, but not under a basal diet. These studies indicate a novel mechanism of suppression of colorectal carcinogenesis induced by a Western-style high-fat diet.


Subject(s)
Adiponectin/deficiency , Colorectal Neoplasms/etiology , Dietary Fats/administration & dosage , Obesity/metabolism , Precancerous Conditions/etiology , Receptors, Adiponectin/deficiency , AMP-Activated Protein Kinase Kinases , Animals , Apoptosis/physiology , Azoxymethane , Blotting, Western , Cell Proliferation , Cell Transformation, Neoplastic/chemically induced , Cell Transformation, Neoplastic/metabolism , Colonic Polyps/etiology , Colonic Polyps/pathology , Colorectal Neoplasms/pathology , Colorectal Neoplasms/physiopathology , Dietary Fats/adverse effects , Intestinal Mucosa/cytology , Intestinal Mucosa/metabolism , Mice , Mice, Knockout , Obesity/physiopathology , Precancerous Conditions/chemically induced , Precancerous Conditions/pathology , Protein Biosynthesis/physiology , Protein Kinases/metabolism , TOR Serine-Threonine Kinases
14.
Diabetes Obes Metab ; 10 Suppl 4: 147-56, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18834442

ABSTRACT

In type 2 diabetes, there is a defect in the regulation of functional beta-cell mass to overcome high-fat (HF) diet-induced insulin resistance. Many signals and pathways have been implicated in beta-cell function, proliferation and apoptosis. The co-ordinated regulation of functional beta-cell mass by insulin signalling and glucose metabolism under HF diet-induced insulin-resistant conditions is discussed in this article. Insulin receptor substrate (IRS)-2 is one of the two major substrates for the insulin signalling. Interestingly, IRS-2 is involved in the regulation of beta-cell proliferation, as has been demonstrated using knockout mice models. On the other hand, in an animal model for human type 2 diabetes with impaired insulin secretion because of insufficiency of glucose metabolism, decreased beta-cell proliferation was observed in mice with beta-cell-specific glucokinase haploinsufficiency (Gck(+/) (-)) fed a HF diet without upregulation of IRS-2 in beta-cells, which was reversed by overexpression of IRS-2 in beta-cells. As to the mechanism underlying the upregulation of IRS-2 in beta-cells, glucose metabolism plays an important role independently of insulin, and phosphorylation of cAMP response element-binding protein triggered by calcium-dependent signalling is the critical pathway. Downstream from insulin signalling via IRS-2 in beta-cells, a reduction in FoxO1 nuclear exclusion contributes to the insufficient proliferative response of beta-cells to insulin resistance. These findings suggest that IRS-2 is critical for beta-cell hyperplasia in response to HF diet-induced insulin resistance.


Subject(s)
Apoptosis/physiology , Diabetes Mellitus, Type 2/metabolism , Insulin Receptor Substrate Proteins/metabolism , Insulin Resistance/physiology , Insulin-Secreting Cells/metabolism , Animals , Cell Proliferation , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/physiopathology , Dietary Fats/metabolism , Female , Gene Expression Regulation , Humans , Hyperplasia/metabolism , Hyperplasia/physiopathology , Insulin Receptor Substrate Proteins/pharmacology , Insulin Resistance/genetics , Male , Mice , Mice, Knockout , Signal Transduction/physiology
15.
Clin Exp Med ; 8(2): 93-9, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18618219

ABSTRACT

The objective of this study was to characterise the fulminant type 1 diabetes mellitus (DM) accompanying abrupt hyperglycaemia and ketonuria observed in insulin receptor substrate 2 (IRS2)-deficient mice. IRS2-deficient mice backcrossed onto the original C57BL/6J:Jc1 background (B6J-IRS2(-/-) mice) for more than 10 generations were used. Eight male IRS2-deficient mice with ketonuria and abrupt increase in plasma glucose concentrations over 25 mmol/l were used as the fulminant type 1 diabetic mice (diabetic mice) and 8 male IRS2-deficient mice (8 weeks old) without glycosuria were used as the control mice. Plasma metabolite, immunoreactive insulin (IRI) and C-peptide concentrations, hepatic energy metabolism related enzyme activities and histopathological change in pancreatic islets were investigated. The diabetic mice showed significantly higher plasma glucose and cholesterol concentrations and lower plasma IRI and C-peptide concentrations than the control mice. In livers of the diabetic mice, glycolytic and malate-aspartate shuttle enzyme activities decreased significantly and gluconeogenic, lipogenic and ketone body synthesis enzyme activities increased significantly compared to those in the control mice. The pancreatic islets of the diabetic mice decreased significantly in size and number of beta cells. The diabetic IRS2-deficient mice did not show the islet-related antibodies observed in the diabetic NOD mice in their sera. The characteristics of the diabetic IRS2-deficient mice resembled those of the human nonautoimmune fulminant type 1 DM. IRS2-deficient mice may be a useful animal model for studying the degradation mechanism of pancreatic beta cells in the process of development of fulminant type 1 DM.


Subject(s)
Diabetes Mellitus, Type 1/etiology , Intracellular Signaling Peptides and Proteins/physiology , Phosphoproteins/physiology , Animals , Diabetes Mellitus, Type 1/blood , Fatty Acids, Nonesterified/blood , Insulin Receptor Substrate Proteins , Male , Mice , Mice, Inbred C57BL , Mice, Inbred NOD , Triglycerides/blood
18.
Integr Biol (Camb) ; 10(9): 549-554, 2018 09 17.
Article in English | MEDLINE | ID: mdl-30140840

ABSTRACT

A DEAE-dextran-MMA copolymer (DDMC)-paclitaxel (PTX) conjugate was prepared using PTX as the guest and DDMC as the host. The resistance of B16F10 melanoma cells to PTX was confirmed, while the DDMC-PTX conjugate showed excellent anticancer activity that followed the Hill equation. The robustness in the tumor microenvironment of the allosteric system was confirmed via BIBO stability. This feedback control system, explained via a transfer function, was very stable and showed the sustainability of the system via a loop, and it showed superior anti-cancer activity without drug resistance from cancer cells. The block diagram of this signal system in the tumor microenvironment used its loop transfer function G(s) and the dN(s) of the external force. This indicial response is an ideal one without a time lag for the outlet response. The cell death rate of DDMC-PTX is more dependent on the Hill coefficient n than on the Michaelis constant Km. This means that this supermolecular reaction with tubulin follows an "induced fit model".


Subject(s)
Melanoma/drug therapy , Paclitaxel/administration & dosage , Zalcitabine/analogs & derivatives , Allosteric Site , Animals , Antineoplastic Agents, Phytogenic/administration & dosage , Cell Line, Tumor , DEAE-Dextran/chemistry , Female , Humans , Kinetics , Melanoma, Experimental , Mice , Mice, Inbred C57BL , Neoplasm Transplantation , Particle Size , Signal Transduction , Tumor Microenvironment , Zalcitabine/administration & dosage
19.
J Clin Invest ; 105(7): 935-43, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10749573

ABSTRACT

Insulin receptor substrates (IRS-1 and -2) are essential for intracellular signaling by insulin and IGF-I, anabolic regulators of bone metabolism. Mice lacking the IRS-1 gene IRS-1(-/-) showed severe osteopenia with low bone turnover. IRS-1 was expressed in osteoblasts, but not in osteoclasts, of wild-type (WT) mice. IRS-1(-/-) osteoblasts treated with insulin or IGF-I failed to induce tyrosine phosphorylation of cellular proteins, and they showed reduced proliferation and differentiation. Osteoclastogenesis in the coculture of hemopoietic cells and osteoblasts depended on IRS-1 expression in osteoblasts and could not be rescued by IRS-1 expression in hemopoietic cells in the presence of not only IGF-I but also 1,25(OH)(2)D(3). In addition, osteoclast differentiation factor (RANKL/ODF) was not induced by these factors in IRS-1(-/-) osteoblasts. We conclude that IRS-1 deficiency in osteoblasts impairs osteoblast proliferation, differentiation, and support of osteoclastogenesis, resulting in low-turnover osteopenia. Osteoblastic IRS-1 is essential for maintaining bone turnover, because it mediates signaling by IGF-I and insulin and, we propose, also by other factors, such as 1,25(OH)(2)D(3).


Subject(s)
Bone Remodeling , Osteoblasts/physiology , Phosphoproteins/physiology , Animals , Bone Diseases, Metabolic/etiology , Bone Diseases, Metabolic/metabolism , Bone Diseases, Metabolic/pathology , Cells, Cultured , Female , Femur/growth & development , Insulin Receptor Substrate Proteins , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Mice, Knockout , Osteoblasts/cytology , Osteoblasts/drug effects , Osteoclasts/cytology , Osteoclasts/drug effects , Osteoclasts/metabolism , Osteoporosis/metabolism , Phosphoproteins/genetics , Signal Transduction , Tibia/growth & development
20.
J Clin Invest ; 108(7): 1001-13, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11581301

ABSTRACT

PPARgamma is a ligand-activated transcription factor and functions as a heterodimer with a retinoid X receptor (RXR). Supraphysiological activation of PPARgamma by thiazolidinediones can reduce insulin resistance and hyperglycemia in type 2 diabetes, but these drugs can also cause weight gain. Quite unexpectedly, a moderate reduction of PPARgamma activity observed in heterozygous PPARgamma-deficient mice or the Pro12Ala polymorphism in human PPARgamma, has been shown to prevent insulin resistance and obesity induced by a high-fat diet. In this study, we investigated whether functional antagonism toward PPARgamma/RXR could be used to treat obesity and type 2 diabetes. We show herein that an RXR antagonist and a PPARgamma antagonist decrease triglyceride (TG) content in white adipose tissue, skeletal muscle, and liver. These inhibitors potentiated leptin's effects and increased fatty acid combustion and energy dissipation, thereby ameliorating HF diet-induced obesity and insulin resistance. Paradoxically, treatment of heterozygous PPARgamma-deficient mice with an RXR antagonist or a PPARgamma antagonist depletes white adipose tissue and markedly decreases leptin levels and energy dissipation, which increases TG content in skeletal muscle and the liver, thereby leading to the re-emergence of insulin resistance. Our data suggested that appropriate functional antagonism of PPARgamma/RXR may be a logical approach to protection against obesity and related diseases such as type 2 diabetes.


Subject(s)
Diabetes Mellitus, Type 2/metabolism , Obesity/metabolism , Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors , Receptors, Retinoic Acid/antagonists & inhibitors , Thiazolidinediones , Transcription Factors/antagonists & inhibitors , 3T3 Cells , Adipose Tissue/metabolism , Animals , Benzhydryl Compounds , Benzoates/metabolism , Benzoates/pharmacology , Biphenyl Compounds/metabolism , Biphenyl Compounds/pharmacology , Epoxy Compounds/metabolism , Epoxy Compounds/pharmacology , Fatty Acids/metabolism , Hyperglycemia/etiology , Hyperglycemia/metabolism , Hypoglycemic Agents/metabolism , Hypoglycemic Agents/pharmacology , Insulin Resistance , Leptin/metabolism , Mice , Mice, Knockout , Nicotinic Acids/metabolism , Nicotinic Acids/pharmacology , Receptors, Adrenergic, beta-3/metabolism , Receptors, Cytoplasmic and Nuclear/agonists , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Retinoic Acid/agonists , Receptors, Retinoic Acid/metabolism , Retinoid X Receptors , Rosiglitazone , Tetrahydronaphthalenes/metabolism , Tetrahydronaphthalenes/pharmacology , Thiazoles/metabolism , Thiazoles/pharmacology , Transcription Factors/agonists , Transcription Factors/metabolism
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