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1.
Artículo en Inglés | MEDLINE | ID: mdl-30425683

RESUMEN

Aims/Introduction: We studied the mechanisms for the possible insulinotropic action of apolipoprotein (Apo) A-I in mouse insulinoma (MIN6) cells. Materials and Methods: The effects of ApoA-I on cAMP production and glucose-stimulated insulin secretion (GSIS), and the dose dependency (ApoA-I at 5, 10, 25, and 50 µg/ml) were determined using MIN6 cells. The effects of the small-interference ribonucleic acid (siRNA) of ATP-binding cassette transporter A1(ABCA1) and Cell division control protein 42 homolog (Cdc42) on the insulinotropic action of ApoA-I was studied, as well as mRNA and protein levels of ABCA1 and Cdc42. Then, the influence of cAMP inhibitor SQ22536, and the cAMP-dependent protein kinase inhibitor Rp-cAMPS on ApoA-I action were studied. Results: Addition of ApoA-I produced cAMP and increased insulin secretion, dose-dependently in high glucose concentration (25 mmmol/l). and ABCA1 protein and Cdc42 mRNA and protein were also enhanced. Specific ABCA1 and Cdc42 siRNA significantly decreased the effects of ApoA-I on insulin secretion compared with negative controls. Manifestations of ABCA1 and Cdc42 mRNA and protein were less than that of the negative control group. Both cAMP inhibiror (SQ22536) and protein kinases inhibitor (Rp-cAMPS) strongly inhibited the effects of ApoA-I on insulin secretion. Conclusions: We demonstrated that ApoA-I enhances glucose-stimulated insulin release in high glucose at least partially through the ABCA1/Cdc42/cAMP/ Protein kinase A (PKA) pathway.

2.
J Atheroscler Thromb ; 23(11): 1276-1285, 2016 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-27301461

RESUMEN

AIM: Sterol regulatory element-binding protein (SREBP)-1c is the dominant liver insulin-stimulated isoform and strongly correlates with diabetic dyslipidemia characterized by hyperinsulinemia [i.e., high-density lipoprotein cholesterol (HDL-C) levels and hypertriglyceridemia]. MicroRNA (miRNA) 33b is harbored in the intron of SREBP-1c and represses ATP-binding cassette, sub-family A, and member 1 (ABCA1) expression, essential for HDL formation. We measured plasma miRNA33b levels as possible biomarkers for diabetic dyslipidemia in patients with type 2 diabetes mellitus (T2DM) showing insulin resistance. METHODS: The participants included 50 patients with T2DM (M/F 31/19) enrolled in an educational program for controlling blood glucose levels at Hirosaki University Hospital. HbA1c, fasting plasma glucose, insulin, and lipid levels were determined. Plasma miRNA33b, miRNA33a and miRNA148a were quantified using a TaqMan® MicroRNA Assay, and values were corrected with reference to miRNA16. RESULTS: Mean BMI of participants were 28.2±6.6 (kg/m2) and the Homeostasis Model Assessment of Insulin Resistance was 4.3±2.7. Patients' laboratory findings indicated diabetic dyslipidemia with insulin resistance. Plasma miRNA33b/16 levels revealed a positive correlation with plasma insulin level (r=0.326, P=0.021), serum C-peptide (r=0.280, P=0.049), and triglyceride (r=0.351, P=0.012), but no association with HDL-C (r=-0.210, P=0.143). The blood level of miRNA33a was approximately 1/150th of that of miRNA33b and was not correlated with the above parameters. CONCLUSION: We postulated that plasma miRNA33b may be useful as a new metabolic biomarker of dyslipidemia in patients with T2DM as well as metabolic syndrome via an insulin/SREBP-1c/miRNA33b/ABCA1 pathway.


Asunto(s)
Biomarcadores/sangre , Diabetes Mellitus Tipo 2/sangre , Dislipidemias/sangre , Resistencia a la Insulina , MicroARNs/sangre , Glucemia/metabolismo , Femenino , Estudios de Seguimiento , Hemoglobina Glucada/metabolismo , Humanos , Insulina/sangre , Lípidos/análisis , Masculino , Síndrome Metabólico/sangre , Persona de Mediana Edad , Pronóstico , Factores de Riesgo
3.
Intern Med ; 55(7): 765-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27041161

RESUMEN

Adrenal insufficiency may occur in patients with liver cirrhosis. The assessment of hypothalamus-pituitary-adrenal function is important in such patients, but there is no consensus as to how it should be performed. We herein report the results of our evaluation of the adrenal function in two patients with hypocortisolism accompanied by liver cirrhosis. The patients lacked the typical features of hypocortisolism. One was diagnosed with hypocortisolism accompanied by liver cirrhosis while the other had secondary adrenal insufficiency caused by a hypothalamic disorder. Hypocortisolism accompanied by liver cirrhosis should be evaluated by endocrine tests to determine its pathogenesis. A low-dose adrenocorticotropic hormone test may be appropriate for non-critically ill cirrhotic patients.


Asunto(s)
Insuficiencia Suprarrenal/sangre , Hormona Adrenocorticotrópica/sangre , Hidrocortisona/sangre , Cirrosis Hepática/sangre , Sistema Hipófiso-Suprarrenal/fisiopatología , Insuficiencia Suprarrenal/complicaciones , Insuficiencia Suprarrenal/fisiopatología , Femenino , Humanos , Cirrosis Hepática/complicaciones , Cirrosis Hepática/fisiopatología , Masculino , Persona de Mediana Edad
4.
Diabetes Res Clin Pract ; 99(1): 30-8, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23137417

RESUMEN

AIMS: Cholesterol efflux with high-density lipoprotein (HDL) particles has an important role in the first step of reverse cholesterol transport (RCT). However, HDL function in type 2 diabetes has not been well investigated thoroughly. We measured cholesterol efflux in 36 patients with type 2 diabetes compared with 9 controls without diabetes. METHODS: The HDL fraction was separated with polyacrylamide gel and recovered using the protein recovery system. Concentration adjusted HDL fraction was used to determine HDL-mediated cholesterol efflux (Efflux-hdl) from THP-1 derived macrophages. We measured paraoxonase-1 (PON 1) activity to determine antioxidation capacity, serum amyloid A protein (SAA) to determine inflammatory response, and carboxymethyl-lysin (CML) to determine antiglucoxidative capacity. RESULTS: Efflux-hdl demonstrated no correlation with plasma apoprotein A-1 (ApoA-I) or HDL-cholesterol in patients with diabetes. PON1 activity in the patients' HDL fraction was positively correlated with Efflux-hdl (r=0.39, p=0.02), and showed a negative tendency with HbA1c levels (r=-0.28, p=0.10). SAA and CML levels did not demonstrate correlation with Efflux-hdl in patients with diabetes. CONCLUSION: We confirmed the functional changes in HDL particles in the patients. Efflux-hdl from macrophages was reduced depending upon the decrease in PON1 activity, which was inversely related to HbA1c levels.


Asunto(s)
Arildialquilfosfatasa/sangre , Diabetes Mellitus Tipo 2/metabolismo , Lipoproteínas HDL/sangre , Anciano , Apolipoproteína A-I/sangre , Apolipoproteína A-I/metabolismo , Aterosclerosis/etiología , Aterosclerosis/metabolismo , Transporte Biológico , Biomarcadores/sangre , Biomarcadores/metabolismo , Línea Celular , Colesterol/sangre , Colesterol/metabolismo , HDL-Colesterol/sangre , HDL-Colesterol/metabolismo , Diabetes Mellitus Tipo 2/inmunología , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Hemoglobina Glucada/análisis , Humanos , Hiperglucemia/etiología , Hiperglucemia/metabolismo , Lipoproteínas HDL/aislamiento & purificación , Lipoproteínas HDL/metabolismo , Lisina/análogos & derivados , Lisina/sangre , Lisina/metabolismo , Macrófagos/metabolismo , Masculino , Persona de Mediana Edad , Proteína Amiloide A Sérica/análisis , Proteína Amiloide A Sérica/metabolismo
5.
Int J Endocrinol ; 2012: 873723, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22654906

RESUMEN

Urocortins (Ucns) are members of the corticotropin-releasing factor (CRF) family of peptides. Ucns would have potent effects on the cardiovascular system via the CRF receptor type 2 (CRF(2) receptor). Regulation and roles of each Ucn have been determined in the vascular system. Ucns have more potent vasodilatory effects than CRF. Human umbilical vein endothelial cells (HUVECs) express Ucns1-3 mRNAs, and the receptor, CRF(2a) receptor mRNA. Ucns1-3 mRNA levels are differentially regulated in HUVECs. Differential regulation of Ucns may suggest differential roles of those in HUVECs. Ucn1 and Ucn2 have strong effects on interleukin (IL)-6 gene expression and secretion in rat aortic smooth muscle A7r5 cells. The increase that we observed in IL-6 levels following Ucn treatment of A7r5 cells suggests that smooth muscle cells may be a source of IL-6 secretion under physiological stress conditions. Ucns are important and unique modulators of vascular smooth muscle cells and act directly or indirectly as autocrine and paracrine factors in the vascular system.

6.
J Clin Lipidol ; 6(1): 74-80, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22264577

RESUMEN

BACKGROUND: Type A or B Niemann-Pick disease (NPD) is characterized by the accumulation of sphingomyelin in the lysosomes and cell membranes. This accumulation results because of a mutation in the sphingomyelin phosphodiesterase-1 (SMPD-1) gene that causes a deficit in the acid sphingomyelinase (ASM). OBJECTIVE: Herein, we report on a new point mutation in the SMPD-1 gene that was discovered in a patient with type B NPD. METHODS AND RESULTS: A culture of the patient's fibroblasts demonstrated that the observed clinical symptoms and reduced plasma high-density lipoprotein cholesterol (HDL-C) were associated with a reduced efflux of cholesterol. Examination of the skin fibroblasts demonstrated that ASM activity was reduced to approximately 60% of that observed in control cells, and a newly identified point mutation was found in codon 494 [Gly (GGT) → Cys (TGT)] in the SMPD-1 gene. Furthermore, repeated measurements of the plasma HDL-C levels remained low (17.5-20.5 mg/dL), and the Apo A-I- or HDL-mediated cholesterol efflux from the patient's fibroblasts was significantly reduced as compared with control fibroblasts. CONCLUSION: In summary, we identified a unique point mutation in a patient with type B NPD that was associated with various clinical findings, including a low plasma HDL-C level. This reduced cellular cholesterol efflux may be implicated, at least in part, in low plasma HDL levels.


Asunto(s)
HDL-Colesterol/sangre , Colesterol/metabolismo , Enfermedad de Niemann-Pick Tipo B/genética , Mutación Puntual , Esfingomielina Fosfodiesterasa/genética , Adenocarcinoma/complicaciones , Adenocarcinoma/diagnóstico , Adenocarcinoma/cirugía , Células Cultivadas , Neoplasias del Colon/complicaciones , Neoplasias del Colon/diagnóstico , Neoplasias del Colon/cirugía , Síndrome de Cushing/complicaciones , Síndrome de Cushing/diagnóstico , Fibroblastos/metabolismo , Estudios de Asociación Genética , Humanos , Hígado/metabolismo , Hígado/patología , Masculino , Persona de Mediana Edad , Enfermedad de Niemann-Pick Tipo B/sangre , Enfermedad de Niemann-Pick Tipo B/complicaciones
7.
Regul Pept ; 174(1-3): 12-7, 2012 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-22120831

RESUMEN

Growth hormone (GH)-releasing peptides (GHRPs) are synthetic peptides that strongly induce GH release. GHRPs act via a specific receptor, the GHRP receptor (GHSR), of which ghrelin is a natural ligand. GHRPs also induce adrenocorticotropic hormone (ACTH) release in healthy subjects. GHRPs or ghrelin stimulate ACTH release via corticotropin-releasing factor (CRF) and arginin vasopressin in the hypothalamus. Stress-activated CRF neurons are suppressed by glucocorticoids in the hypothalamic paraventricular nucleus (PVN), while CRF gene is up-regulated by glucocorticoids in the PVN cells without the influence of input neurons. However, little is known about the regulation of ghrelin and GHSR type 1a (GHSR1a) genes by glucocorticoids in PVN cells. To elucidate the regulation of ghrelin and GHSR gene expression by glucocorticoids in PVN cells, here we used a homologous PVN neuronal cell line, hypothalamic 4B, because these cells show characteristics of the parvocellular neurons of the PVN. These cells also express ghrelin and GHSR1a mRNA. Dexamethasone increased ghrelin mRNA levels. A potent glucocorticoid receptor antagonist, RU-486, significantly blocked dexamethasone-induced increases in ghrelin mRNA levels. Dexamethasone also significantly stimulated GHSR1a mRNA and protein levels. Finally, ghrelin increased CRF mRNA levels, as did dexamethasone. Incubation with both dexamethasone and ghrelin had an additive effect on CRF and ghrelin mRNA levels. The ghrelin-GHSR1a system is activated by glucocorticoids in the hypothalamic cells.


Asunto(s)
Dexametasona/farmacología , Ghrelina/genética , Hipotálamo/citología , Hipotálamo/efectos de los fármacos , Receptores de Ghrelina/genética , Animales , Células Cultivadas , Relación Dosis-Respuesta a Droga , Ghrelina/metabolismo , Hipotálamo/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Ghrelina/metabolismo , Relación Estructura-Actividad
8.
Peptides ; 33(1): 149-55, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22138165

RESUMEN

Corticotropin-releasing factor (CRF) is involved in a variety of physiological functions including regulation of hypothalamo-pituitary-adrenal axis activity during stressful periods. Urocortins (Ucns) are known to be members of the CRF family peptides. CRF has a high affinity for CRF receptor type 1 (CRF(1) receptor). Both Ucn2 and Ucn3 have very high affinity for CRF receptor type 2 (CRF(2) receptor) with little or no binding affinity for the CRF(1) receptor. Gonadotropin-releasing hormone (GnRH) is known to be involved in the regulation of the stress response. Gonadotropin-inhibitory hormone (GnIH) neurons interact directly with GnRH neurons, and the action of GnIH is mediated by a novel G-protein coupled receptor, Gpr147. This study aimed to explore the possible function of CRF family peptides and the regulation of GnRH mRNA in hypothalamic GnRH cells. Both mRNA and protein expression of the CRF(1) receptor and CRF(2) receptor were found in hypothalamic GnRH N39 cells. CRF suppressed GnRH mRNA levels via the CRF(1) receptor, while Ucn2 increased the levels via the CRF(2) receptor. Both CRF and Ucn2 increased Gpr147 mRNA levels. The results indicate that CRF and Ucn2 can modulate GnRH mRNA levels via each specific CRF receptor subtype. Finally, CRF suppressed GnRH protein levels, while Ucn2 increased the levels. Differential regulation of GnRH by CRF family peptides may contribute to the stress response and homeostasis in GnRH cells.


Asunto(s)
Hormona Liberadora de Corticotropina/farmacología , Hormona Liberadora de Gonadotropina/genética , Hipotálamo/metabolismo , Urocortinas/farmacología , Animales , Línea Celular , Hormona Liberadora de Corticotropina/antagonistas & inhibidores , Regulación de la Expresión Génica , Hormona Liberadora de Gonadotropina/metabolismo , Hipotálamo/citología , Hipotálamo/efectos de los fármacos , Ratones , Pirimidinas/farmacología , Pirroles/farmacología , Receptores de Hormona Liberadora de Corticotropina/genética , Receptores de Hormona Liberadora de Corticotropina/metabolismo , Receptores de Neuropéptido/genética , Receptores de Neuropéptido/metabolismo
9.
Stress ; 14(4): 357-67, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21438777

RESUMEN

Corticotropin-releasing factor (CRF) is a major regulatory peptide in the hypothalamic-pituitary-adrenal (HPA) axis under stress conditions. In response to stress, CRF is produced in the hypothalamic paraventricular nucleus. Forskolin- or pituitary adenylate cyclase-activating polypeptide-stimulated CRF gene transcription is mediated by the cyclic AMP (cAMP) response element on the CRF 5'-promoter region. Estrogens enhance activation of the CRF gene in stress, while inducible cAMP-early repressor suppresses the stress response via inhibition of the cAMP-dependent CRF gene. Glucocorticoid-dependent repression of cAMP-stimulated CRF promoter activity is mediated by both the negative glucocorticoid-response element and the serum-response element, while interleukin-6 (IL-6) stimulates the CRF gene. Suppressor of cytokine signaling-3, stimulated by IL-6 and cAMP, is involved in the negative regulation of CRF gene expression. Such complex mechanisms contribute to stress responses and homeostasis in the hypothalamus. Moreover, disruption of the HPA axis may cause a number of diseases related to stress. For example, CRF-induced p21-activated kinase 3 mRNA expression may be related to the proliferation of corticotrophs in Nelson's syndrome. A higher molecular weight form of immunoreactive ß-endorphin, putative proopiomelanocortin (POMC), is increased in CRF-knockout mice, suggesting the important role of CRF in the processing of POMC through changes in prohormone convertase type-1 expression levels.


Asunto(s)
Hormona Liberadora de Corticotropina/fisiología , Sistema Hipotálamo-Hipofisario/fisiología , Hipotálamo/metabolismo , Sistema Hipófiso-Suprarrenal/fisiología , Transducción de Señal , Estrés Psicológico/fisiopatología , Animales , Hormona Liberadora de Corticotropina/biosíntesis , Hormona Liberadora de Corticotropina/genética , AMP Cíclico/metabolismo , Glucocorticoides/fisiología , Humanos , Interleucina-6/fisiología , Ratones , Síndrome de Nelson/fisiopatología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/fisiología , Proopiomelanocortina , Proteínas Supresoras de la Señalización de Citocinas/fisiología , Factor de Transcripción AP-1/fisiología
10.
Stress ; 14(5): 520-9, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21438782

RESUMEN

Corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) play a central role in regulating the stress response. In response to stress, CRF and AVP neurons in the hypothalamic paraventricular nucleus secrete the peptides to stimulate the release of adrenocorticotropic hormone from the anterior pituitary. Ghrelin, an endogenous ligand of the growth hormone-releasing peptide receptors (GHSR), has been shown to stimulate the release of CRF and AVP by rat hypothalamic explants. However, little is known about the ability of the ghrelin signaling pathways to activate the CRF and AVP genes in the hypothalamus. In the present study, we examined the direct effect of ghrelin on CRF and AVP gene expression in hypothalamic 4B cells, which show the characteristics of the hypothalamic parvocellular paraventricular nucleus neurons. Cells were transfected with CRF or AVP promoter to examine the activity of each promoter. Ghrelin stimulated the promoter activities and mRNA levels for both CRF and AVP. The involvement of a protein kinase pathway was examined using inhibitors. Protein kinase A and phospholipase C pathways were shown to be involved in ghrelin-induced increases in both CRF and AVP promoter activities. GHSR type 1a (GHSR1a) mRNA levels were also increased by ghrelin, and these ghrelin-induced levels were suppressed by a GHSR1a antagonist. Thus, ghrelin-dependent pathways are involved in the regulation of CRF and AVP gene expression in the hypothalamus: ghrelin, an orexigenic hormone, stimulates CRF, an anorexigenic/anxiogenic factor in the hypothalamus, resulting in hypothalamic-pituitary-adrenal axis activation to stimulate the release of glucocorticoids.


Asunto(s)
Arginina Vasopresina/biosíntesis , Hormona Liberadora de Corticotropina/biosíntesis , Ghrelina/farmacología , Animales , Células Cultivadas , AMP Cíclico/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Expresión Génica/efectos de los fármacos , Hipotálamo/metabolismo , Núcleo Hipotalámico Paraventricular/citología , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Núcleo Hipotalámico Paraventricular/metabolismo , Regiones Promotoras Genéticas/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , ARN Mensajero/metabolismo , Ratas , Fosfolipasas de Tipo C/metabolismo
11.
J Atheroscler Thromb ; 17(11): 1183-9, 2010 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-20733269

RESUMEN

AIMS: We studied the effect of insulin on HDL-mediated cholesterol efflux from macrophages. The potential involvement of cholesteryl ester hydrolysis and membrane cholesterol transport was also addressed. METHODS: Human monocyte-derived THP-1 cells were developed into macrophages. Cholesterol efflux was measured by incubating macrophages, labeled with [³H]-cholesterol, with HDL for 24 h. The cells were treated with insulin (0-500 nM) for 30 min prior to the addition of HDL. To investigate the molecular mechanisms of the effect of insulin, the expressions of neutral cholesteryl ester hydrolase (nCEH) and ATP-binding cassette transporter (ABC) G1 were analyzed. RESULTS: Insulin inhibited, in a concentration-dependent manner, HDL-mediated cholesterol efflux from macrophages. Insulin also inhibited the enzyme activity of nCEH and its mRNA and protein expression in cells. Insulin also suppressed the expressions of mRNA and protein for ABCG1. CONCLUSIONS: Insulin inhibits HDL-mediated cholesterol efflux from macrophages, which may result from the suppression of nCEH and ABCG1 expressions. Our findings show part of the potential molecular mechanism of atherogenesis in type 2 diabetes with hyperinsulinemia.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Colesterol/metabolismo , Insulina/farmacología , Lipoproteínas HDL/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Esterol Esterasa/metabolismo , Transportador 1 de Casete de Unión a ATP , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1 , Transportadoras de Casetes de Unión a ATP/genética , Western Blotting , Células Cultivadas , Humanos , Hipoglucemiantes/farmacología , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serina Proteasas , Esterol Esterasa/genética
13.
Endocr J ; 57(3): 267-72, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20086312

RESUMEN

Cushing's syndrome, including its mild form/state of adrenal-dependent subset (subclinical Cushing's syndrome; subCS), is known to enhance glucose intolerance, hypertension and obesity. Recently, subclinical Cushing's disease (subCD) has been identified, but its prevalence and the extent of consequent metabolic derangement are unclear. We screened 90 type 2 diabetic patients hospitalized in our department for subCD, according to the diagnostic guideline proposed by the working group of Japanese Ministry of Health, Welfare and Labor in 2006. Plasma ACTH and cortisol levels in the morning and at midnight were determined, and overnight 0.5 mg dexamethasone suppression test (DST) was performed. Those who showed poor cortisol suppression in DST underwent the desmopressin (DDAVP) test. Fifty-seven patients (63.3%) demonstrated abnormally high midnight cortisol levels (>or=2.5 microg/dL), while only nine of them failed to suppress plasma cortisol levels to <3 microg/dL after DST. Although none of the eight patients who underwent the DDAVP test demonstrated the anticipated paradoxical rise in plasma ACTH, these eight patients (8.9%) endocrinologically met the screening criteria of subCD. Since a considerable percentage of pituitary adenomas causing overt Cushing's disease are not identifiable in magnetic resonance imaging, many of those causing subCD may also be unidentifiable. Further follow-up studies including confirmatory testing and pituitary imaging are necessary.


Asunto(s)
Hormona Adrenocorticotrópica/sangre , Diabetes Mellitus Tipo 2/diagnóstico , Hidrocortisona/sangre , Adulto , Anciano , Ritmo Circadiano , Síndrome de Cushing/diagnóstico , Diabetes Mellitus Tipo 2/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/diagnóstico , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/epidemiología
14.
Rinsho Byori ; 58(12): 1203-10, 2010 Dec.
Artículo en Japonés | MEDLINE | ID: mdl-21348240

RESUMEN

It has been clarified that several transcription factors and functioning proteins play important roles regulating intracellular cholesterol levels. They bind to the ER membrane and sense changes in cholesterol levels in the membrane through SSD. An important membrane-binding transcription factor, SREBP, is retained in the ER membrane, forming an SREBP/SCAP/INSIG trimer when cellular cholesterol levels are abundant. This complex blocks the transport of SREBPs to the Golgi apparatus, thus preventing subsequent transcriptional activation. When cellular cholesterol levels are low, the ER cholesterol concentration is below a threshold value ( <5 mol %). Under these conditions, SCAP escorts SREBPs from the ER to Golgi apparatus by binding to a component of the CopII protein coat. Once in the Golgi apparatus, the SREBPs are proteolytically processed to generate their nuclear form, the bHLH leucine zipper, that activates genes for cholesterol synthesis and uptake. HMG-CoA reductase is also post-transcriptionally regulated by sterol, with INSIG binding of the protein leading to its proteosomal degradation. We demonstrated that Tangier disease and Niemann-Pick disease type B and type C are metabolic disorders of membrane cholesterol. These diseases are not so common in clinical medicine; however, it is very important to understand membrane lipid metabolism, especially in the ER. It will be clarified in the near future disorders of membrane cholesterol trafficking contribute to the pathogeneses of many kinds of disease affecting through ER functioning.


Asunto(s)
Membrana Celular/metabolismo , Colesterol/metabolismo , Trastornos del Metabolismo de los Lípidos/metabolismo , Proteínas de Unión a los Elementos Reguladores de Esteroles/fisiología , Acetil-CoA C-Aciltransferasa/fisiología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Transporte Biológico , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/fisiología , Trastornos del Metabolismo de los Lípidos/etiología , Proteínas de la Membrana/fisiología , Complejos Multiproteicos , Enfermedades de Niemann-Pick/etiología , Enfermedades de Niemann-Pick/metabolismo , Enfermedad de Tangier/etiología , Enfermedad de Tangier/metabolismo
16.
Atherosclerosis ; 206(2): 434-8, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19376519

RESUMEN

High-density lipoprotein (HDL) mediates cholesterol efflux, which is the initial and rate-limiting step of reverse cholesterol transport. The present study was undertaken to evaluate the effect, on macrophage cholesterol efflux, of functional modification of HDL by its glycation. We also investigated the effects of the glycation-inhibitors metformin (MF) and aminoguanidine (AG) on glycated HDL-mediated cholesterol efflux. Human plasma HDL (5mg protein/mL) was glycated by incubation with 3-deoxyglucosone (3-DG). Glycation was monitored by measuring carboxymethyl-lysine (CML). HDL-mediated cholesterol efflux was determined using human THP-1-derived macrophages pre-labeled with [(3)H]-cholesterol. To measure expression of potential factors related to the efflux in the macrophages, ATP-binding cassette transporter (ABC) G1 was analyzed by real-time quantitative RT-PCR and Western blot. Glycation of HDL significantly reduced the HDL-mediated cholesterol efflux from THP-1-derived macrophages (87.7+/-4.2% of control, n=9, p<0.0001). In the presence of metformin or aminoguanidine (100mM), glycated HDL-mediated cholesterol efflux was restored to 97.5+/-4.3% and 96.9+/-3.1%, respectively. Exogenous HDL reduced ABCG1 mRNA and protein expression in THP-1-derived macrophages, but glycation deprived HDL of this effect. We conclude that glycated HDL particles are ineffective as acceptors of ABCG1-mediated cholesterol efflux; and this may explain, at least in part, accelerated atherosclerosis in diabetic patients. Metformin serves as a possible candidate to restore impaired cholesterol efflux and reverse cholesterol transport.


Asunto(s)
Colesterol/metabolismo , Lipoproteínas HDL/fisiología , Macrófagos/metabolismo , Metformina/farmacología , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1 , Transportadoras de Casetes de Unión a ATP/metabolismo , Células Cultivadas , Desoxiglucosa/análogos & derivados , Desoxiglucosa/metabolismo , Expresión Génica/efectos de los fármacos , Productos Finales de Glicación Avanzada/antagonistas & inhibidores , Glicosilación , Guanidinas/farmacología , Humanos , Lipoproteínas HDL/química
17.
Diabetes Metab Res Rev ; 24(8): 642-50, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18973207

RESUMEN

BACKGROUND: Small sensory fibre dysfunction has been recently recognized as a component of impaired glucose tolerance and insulin resistance (IR) syndrome. However, few studies have investigated whether small sensory fibre dysfunction develops in normoglycaemic or pre-diabetic animal models of IR and/or hyperinsulinaemia. In addition, scant information is available on the metabolic features of IR in relation to small sensory fibre dysfunction due to the progressive failure of beta cells to compensate for IR during the development of frank diabetes. METHODS: Longitudinal trends for thermal and mechanical nociceptive responses were assessed in 8-36-week-old male obese Zucker rats, 8-36-week-old male Zucker diabetic fatty (ZDF) rats, and 10-39-week-old male Wistar rats that continued to receive exogenous insulin (2-4 U/day) from subcutaneously implanted insulin pellets. Data were compared with the metabolic disorders in these rats. RESULTS: Both obese Zucker and ZDF rats at 8 weeks of age showed compensatory hyperinsulinaemia and developed thermal hyperalgesia prior to the onset of overt hyperglycaemia. These animals also exhibited progression from thermal hyperalgesia to hypoalgesia, which occurred more rapidly and coincided with a more rapid decline in pancreatic insulin secretion in ZDF rats than in obese Zucker rats. Non-diabetic rats treated with insulin tended to show thermal and mechanical hypoalgesia that was detectable 12-20 weeks after treatment. CONCLUSION: In addition to insulin treatment, IR with or without compensatory hyperinsulinaemia is associated with nociceptive dysfunction of different phenotypes, independent of glycaemic levels.


Asunto(s)
Diabetes Mellitus Tipo 2/fisiopatología , Hiperinsulinismo/fisiopatología , Resistencia a la Insulina/fisiología , Dimensión del Dolor , Dolor/fisiopatología , Animales , Glucemia/metabolismo , Peso Corporal , Hiperglucemia/sangre , Masculino , Obesidad/fisiopatología , Ratas , Ratas Zucker , Delgadez/fisiopatología
18.
J Atheroscler Thromb ; 15(1): 20-5, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18270459

RESUMEN

AIM: ApoA-I and HDL promote cellular cholesterol efflux in the early stages of the reverse cholesterol transport (RCT) pathway. A low plasma HDL-C level is characteristic of atherogenic dyslipidemia in patients with type 2 diabetes. We evaluated plasma lipid levels and the expression of factors related to RCT in type 2 diabetic patients, and the effects of an HMG-CoA reductase inhibitor, simvastatin, were studied. METHODS: Messenger RNA (mRNA) expression in circulating mononuclear cells was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), focusing on the following factors: liver X receptor alpha (LXR alpha), ATP-binding cassette A1 (ABCA1), scavenger receptor class B type 1 (SR-B1), apolipoprotein E (ApoE), apolipoprotein A-1 (ApoA-1), caveolin, and cholesterol ester transfer protein (CETP). Type 2 diabetic subjects (n=29) were divided into three subgroups: patients with normolipidemia (DM group, n=11), patients with untreated hyperlipidemia (DMHL group, n=10), and those with hyperlipidemia treated with simvastatin 5-10mg/day (DMST group, n=8). The control group (CNT group) included seven healthy volunteers. RESULTS: Simvastatin treatment significantly increased plasma levels of ApoA-I compared to the other three groups. Simvastatin treatment improved the expression of mRNA for LXRalpha, ABCA1, and ApoA-I compared with DMHL or control groups. CONCLUSION: Our data suggest that RCT may be reduced in type 2 diabetic patients with hyperlipidemia, and simvastatin may be able to improve reverse cholesterol transport for this population of diabetic patients.


Asunto(s)
HDL-Colesterol/sangre , Colesterol/sangre , Diabetes Mellitus Tipo 2/sangre , Hiperlipidemias/tratamiento farmacológico , Simvastatina/farmacología , Anciano , Apolipoproteína A-I/sangre , Femenino , Expresión Génica , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Masculino , Persona de Mediana Edad
19.
Diabetes Res Clin Pract ; 79(2): 357-61, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17980929

RESUMEN

Serum cystatin C (CysC) has been proposed as a potentially superior marker for the evaluation of renal function because it was more sensitive and accurate for the estimation of glomerular filtration rate (GFR) than other markers. We evaluated the clinical usefulness of CysC in diabetic nephropathy. The study was performed on 414 Japanese diabetic patients. We compared serum CysC levels with serum creatinine levels, urinary concentrations of albumin, transferrin and type IV collagen, and creatinine clearance (Ccr). Then, the correlation between serum CysC levels and high-sensitivity C-reactive protein (H-CRP) levels were examined. When the patients were classified by renal function, 19% of the patients were free from nephropathy, 49% had microalbuminuria, 28% had persistent proteinuria, and 4% had end stage renal disease. The serum CysC levels increased with the progression of nephropathy, and significantly higher in overt nephropathy, but not significant in early nephropathy. Serum CysC levels were well-correlated with H-CRP levels in the patients without nephropathy. These results indicate that serum CysC would be practical for the evaluation of renal function in diabetic patients with overt nephropathy but not early nephropathy and might be related with a risk for cardiovascular events in patients without nephropathy.


Asunto(s)
Biomarcadores/sangre , Cistatinas/metabolismo , Diabetes Mellitus Tipo 2/sangre , Angiopatías Diabéticas/diagnóstico , Nefropatías Diabéticas/fisiopatología , Anciano , Nitrógeno de la Urea Sanguínea , Cistatina C , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Angiopatías Diabéticas/sangre , Nefropatías Diabéticas/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad
20.
Kansenshogaku Zasshi ; 81(6): 720-5, 2007 Nov.
Artículo en Japonés | MEDLINE | ID: mdl-18095472

RESUMEN

The frequency of diabetes mellitus has risen in Japan as the traditional diet has become increasing Americanized and society has aged. With this has come a rise in infectious diseases and complications elderly diabetic patients and a growing need for appropriate management to maintain their quality of life (QOL) and minimize medical measures. Subjects were 98 diabetic patients-60 men and 38 women hospitalized for intravenous antibiotic treatment of infectious disease from 2002 to 2005. We studied plasma glucose control, plasma and urinary protein levels related to nephropathy, and inflammatory responses to treatment. Subjects were divided into good (under 6.5%), fair (from 6.5% to 8.0%), poor (over 8.0%) and severe (over 10%) groups by HbA1c level on admission. We then compared white blood cell counts, CRP levels and the antibacterial medication periods. Those with poorly controlled plasma glucose control, hypoalbuminuria and interrupted or untreated diabetes required significantly longer antibacterial administration. Insulin was increased by the complications of infection, and decreased as infection ameliorated. Appropriate antibiotic administration is essential for diabetic patients with infectious disease, in addition to early intervention, strict plasma glucose control, continuous treatment, and maintenance of good nutrition. Such treatment improves QOL, shortens antibiotic administration, staves off antibiotic-resistant bacteria, and cuts medical costs.


Asunto(s)
Complicaciones de la Diabetes/sangre , Infecciones/sangre , Anciano , Antibacterianos/administración & dosificación , Glucemia/análisis , Proteína C-Reactiva/análisis , Femenino , Humanos , Recuento de Leucocitos , Masculino
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