RESUMO
The liver plays a major role in the formation of H2S, a novel signaling molecule. Diabetes is associated with lower blood levels of H2S. This study investigated the activities of cystathionine-γ-lyase (CSE, the enzyme that catalyzes H2S formation) in livers of type 1 diabetic (T1D) animals and in peripheral blood mononuclear cells (PBMC) isolated from T1D patients. T1D is associated with both hyperketonemia (acetoacetate and ß-hydroxybutyrate) and hyperglycemia. This study also examined the role of hyperglycemia and hyperketonemia per se in decreased CSE activity using U937 monocytes and PBMC isolated from healthy subjects. Livers from streptozotocin-treated T1D rats demonstrated a significantly higher reactive oxygen species production, lower CSE protein expression and activity, and lower H2S formation compared with those of controls. Studies with T1D patients showed a decrease in CSE protein expression and activity in PBMC compared with those of age-matched normal subjects. Cell culture studies demonstrated that high glucose (25 mm) and/or acetoacetate (4 mm) increased reactive oxygen species, decreased CSE mRNA expression, protein expression, and enzymatic activity, and reduced H2S levels; however, ß-hydroxybutyrate treatment had no effect. A similar effect, which was also observed in PBMC treated with high glucose alone or along with acetoacetate, was prevented by vitamin D supplementation. Studies with CSE siRNA provide evidence for a relationship between impaired CSE expression and reduced H2S levels. This study demonstrates for the first time that both hyperglycemia and hyperketonemia mediate a reduction in CSE expression and activity, which can contribute to the impaired H2S signaling associated with diabetes.
Assuntos
Cistationina gama-Liase/metabolismo , Diabetes Mellitus Tipo 1/enzimologia , Fígado/enzimologia , Monócitos/enzimologia , Animais , Cistationina gama-Liase/sangue , Cistationina gama-Liase/genética , Diabetes Mellitus Tipo 1/sangue , Inativação Gênica , Humanos , Masculino , Reação em Cadeia da Polimerase , RNA Interferente Pequeno/genética , Ratos , Ratos Sprague-Dawley , Células U937RESUMO
Cardiomyopathy is a rare but life-threatening condition in children. Myocarditis is the leading cause of dilated cardiomyopathy (DCM) and prognosis is generally poor without heart transplantation. We report a rare case of hypocalcemic DCM due to primary hypoparathyroidism in a male infant. In our patient, aggressive management of hypoparathyroidism significantly improved the manifestations of DCM. He is currently 10 years old and has no symptoms of exercise intolerance. Latest echocardiogram revealed near-normal cardiac function. Our case emphasizes that early diagnosis of this treatable cause of cardiomyopathy prevents serious sequelae.
Assuntos
Cardiomiopatia Dilatada/etiologia , Hipocalcemia/etiologia , Hipoparatireoidismo/complicações , Cardiomiopatia Dilatada/diagnóstico , Humanos , Lactente , MasculinoRESUMO
AIMS/HYPOTHESIS: We had previously reported that stromal cell-derived factor 1 (SDF-1) mediates chemorepulsion of diabetogenic T cell adhesion to islet microvascular endothelium through unknown mechanisms in NOD mice. Here we report that SDF-1-mediated chemorepulsion occurs through slit homologue (SLIT)2-roundabout, axon guidance receptor, homologue 1 (Drosophila) (ROBO1) interactions. METHODS: C-X-C receptor (CXCR)4 and ROBO1 protein expression was measured in mouse and human T cells. Parallel plate flow chamber adhesion and detachment studies were performed to examine the molecular importance of ROBO1 and SLIT2 for SDF-1-mediated T cell chemorepulsion. Diabetogenic splenocyte transfer was performed in NOD/LtSz Rag1(-/-) mice to examine the effect of the SDF-1 mimetic CTCE-0214 on adoptive transfer of diabetes. RESULTS: CXCR4 and ROBO1 protein expression was elevated in diabetic NOD/ShiLtJ T cells over time and coincided with the onset of hyperglycaemia. CXCR4 and ROBO1 expression was also increased in human type 1 diabetic T cells, with ROBO1 expression maximal at less than 1 year post diagnosis. Cell detachment studies revealed that immunoneutralisation of ROBO1 prevented SDF-1-mediated chemorepulsion of NOD T cell firm adhesion to TNFα-stimulated islet endothelial cells. SDF-1 increased NOD T cell adhesion to recombinant adhesion molecules, a phenomenon that was reversed by recombinant SLIT2. Finally, we found that an SDF-1 peptide mimetic prevented NOD T cell adhesion in vitro and significantly delayed adoptive transfer of autoimmune diabetes in vivo. CONCLUSIONS/INTERPRETATION: These data reveal a novel molecular pathway, which regulates diabetogenic T cell recruitment and may be useful in modulating autoimmune diabetes.
Assuntos
Quimiocina CXCL12/metabolismo , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Receptores CXCR4/metabolismo , Receptores Imunológicos/metabolismo , Animais , Western Blotting , Adesão Celular/fisiologia , Células Cultivadas , Quimiocina CXCL12/genética , Feminino , Peptídeos e Proteínas de Sinalização Intercelular/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Ligação Proteica , Receptores CXCR/genética , Receptores CXCR/metabolismo , Receptores CXCR4/genética , Receptores Imunológicos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/imunologia , Linfócitos T/metabolismo , Proteínas RoundaboutRESUMO
The plasma levels of apoptotic DNA ladders (i.e., apoptosemia) and gamma-glutamyltranspeptidase (GGT) in diabetic outpatients and rats were investigated. Apoptotic DNA ladders were detected in plasma from 26.8% of type 1 (T1) and 18.5% of type 2 (T2) diabetic children 1-20 years of age, 25.7% of hospitalized children and 35.7% of adult RA outpatients, but in only 3.5% of adult pre-op patients. Plasma from 7.7% of young streptozotocin-induced diabetic but not control rats contained apoptotic DNA ladders. Apoptosemia was detected more often in male T1 (31%) and T2 (30.8%) diabetic outpatients than in female T1 (20.8%) and T2 (15.4%) diabetic outpatients. GGT in apoptosemic plasma was significantly higher than in nonapoptosemic plasma from T1 (P = 0.001) but not T2 diabetic children. The highest amounts of apoptotic DNA were detected most often in diabetic children > or =14 years of age. In vitro study results suggest that cell-free apoptotic DNA ladders appear prior to an increase in GGT activity in serum from human blood incubated at 37 degrees C. The results suggest that 24.7% of plasma samples from diabetic children contained apoptotic DNA ladders, the incidence and amounts of apoptotic DNA ladders were higher in the older diabetic children, and GGT was elevated in apoptosemic T1 diabetic children (P = 0.01). The results indicate that "silent" apoptosemia occurs in T1 and T2 diabetic children and suggest elevated GGT in diabetic children could be due to release from apoptotic cells.
Assuntos
Apoptose , DNA/sangue , Diabetes Mellitus/sangue , gama-Glutamiltransferase/sangue , Adolescente , Adulto , Fatores Etários , Animais , Índice de Massa Corporal , Criança , Pré-Escolar , DNA/metabolismo , Diabetes Mellitus/enzimologia , Diabetes Mellitus/genética , Feminino , Humanos , Lactente , Masculino , Ratos , Ratos Wistar , gama-Glutamiltransferase/metabolismoRESUMO
Hyperglycemic hyperosmolar syndrome (HHS) is a clinical entity not identical to diabetic ketoacidosis (DKA), and with a markedly higher mortality. Children with HHS can also present with concomitant DKA. Patients with HHS (with or without DKA) are profoundly dehydrated but often receive inadequate fluid resuscitation as well as intravenous insulin therapy based on traditional DKA protocols, and this can lead to devastating consequences. In this article, we briefly review HHS along with a report of an adolescent who presented with HHS and DKA and was initially managed as DKA. She went into hypotensive shock and developed severe, multiorgan failure. A thorough understanding of the pathophysiology of HHS and its differences from DKA in terms of initial management is crucial to guide management and improve outcomes. Additionally, fluid therapy in amounts concordant with the degree of dehydration remains the mainstay therapy.
Assuntos
Cetoacidose Diabética/terapia , Hidratação/efeitos adversos , Coma Hiperglicêmico Hiperosmolar não Cetótico/terapia , Hipotensão/etiologia , Insuficiência de Múltiplos Órgãos/etiologia , Adolescente , Cetoacidose Diabética/complicações , Feminino , Humanos , Coma Hiperglicêmico Hiperosmolar não Cetótico/complicações , PrognósticoRESUMO
The long-term complications of diabetes are the leading causes of morbidity and mortality in the type 1 diabetic population and remain a major public health issue. Hyperglycemia is one of the major risk factors in the development of vascular complications. A growing body of evidence indicates that hyperglycemia leads to increased oxidative stress and monocyte and endothelial cell dysfunction. In addition to hyperglycemia, type 1 diabetic patients frequently experience ketosis (hyperketonemia). The blood concentration of ketone bodies reaches higher than 25mM in diabetics with severe ketosis. Traditionally, clinical practice has considered hypertketonemia to be present only in type 1 diabetic patients. Newer data indicate that diabetic ketoaciosis or hyperketonemia co-exists with hyperglycemia among older type 2 diabetic patients and in African Americans and other minority groups with type 2 diabetes. This review will focus on the role of hyperketonemia in the etiology of oxidative stress in diabetic patients. The data presented here illustrate that the ketone body acetoacetate (AA) can generate superoxide radicals and cause increases in oxidative stress and cellular dysfunction. The data included in this review demonstrate that blood levels of markers of oxidative stress are elevated in hyperketonemic patients compared with those of normoketonemic diabetic patients. Thus, both in vitro and in vivo research indicate that ketosis can generate oxygen radicals and result in excess cellular oxidative stress in type 1 diabetic patients. Elevated oxidative stress levels in ketotic patients can play a significant role in the development of vascular inflammation and contribute to the increased incidence of vascular disease and complications associated with type 1 diabetes.
RESUMO
An elevated blood level of tumor necrosis factor (TNF)-alpha is a validated marker of vascular inflammation, which can result in the development of vascular disease and atherosclerosis. This study examined the hypothesis that ketosis increases the TNF-alpha secretion, both in a cell culture model using U937 monocytes and in type 1 diabetic patients in vivo. U937 cells were cultured with ketone bodies (acetoacetate [AA] and beta-hydroxybutyrate [BHB]) in the presence or absence of high levels of glucose in medium at 37 degrees C for 24 h. This study demonstrates the following points. First, hyperketonemic diabetic patients have significantly higher levels of TNF-alpha than normoketonemic diabetic patients (P < 0.01) and normal control subjects (P < 0.01). There was a significant correlation (r = 0.36, P < 0.05; n = 34) between ketosis and oxidative stress as well as between oxidative stress and TNF-alpha levels (r = 0.47, P < 0.02; n = 34) in the blood of diabetic patients. Second, ketone body AA treatment increases TNF-alpha secretion, increases oxygen radicals production, and lowers cAMP levels in U937 cells. However, BHB did not have any effect on TNF-alpha secretion or oxygen radicals production in U937 cells. Third, exogenous addition of dibutyryl cAMP, endogenous stimulation of cAMP production by forskolin, and antioxidant N-acetylcysteine (NAC) prevented stimulation of TNF-alpha secretion caused by AA alone or with high glucose. Similarly, NAC prevented the elevation of TNF-alpha secretion and lowering of cAMP levels in H(2)O(2)-treated U937 cells. Fourth, the effect of AA on TNF-alpha secretion was inhibited by specific inhibitors of protein kinase A (H89), p38-mitogen-activated protein kinase (SB203580), and nuclear transcription factor (NF)kappaB (NFkappaB-SN50). This study demonstrates that hyperketonemia increases TNF-alpha secretion in cultured U937 monocytic cells and TNF-alpha levels in the blood of type 1 diabetic patients and is apparently mediated by AA-induced cellular oxidative stress and cAMP deficiency.
Assuntos
Ácido 3-Hidroxibutírico/farmacologia , Acetoacetatos/farmacologia , Antioxidantes/farmacologia , AMP Cíclico/fisiologia , Diabetes Mellitus Tipo 1/fisiopatologia , Corpos Cetônicos/sangue , Monócitos/fisiologia , Estresse Oxidativo/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Acetilcisteína/farmacologia , AMP Cíclico/sangue , Diabetes Mellitus Tipo 1/sangue , Humanos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Monócitos/efeitos dos fármacos , Proteína Quinase C/sangue , Valores de Referência , Acetato de Tetradecanoilforbol/farmacologia , Células U937RESUMO
OBJECTIVE: Diabetic patients have elevated blood levels of interleukin-6 (IL-6), which is known to increase inflammation and the development of vascular disease and atherosclerosis. This study examined the hypothesis that ketosis increases the circulating levels of IL-6 in type 1 diabetic patients as well as the secretion of IL-6 in vitro in a cell culture model using U937 monocytes. RESEARCH DESIGN AND METHODS: Fasting blood was obtained from type 1 diabetic patients and healthy siblings. To examine the effect of ketosis, U937 monocytes were cultured with ketone bodies (acetoacetate [AA], beta-hydroxybutyrate [BHB]) in the presence or absence of high glucose levels in the medium at 37 degrees C for 24 h. IL-6 was determined by the sandwich enzyme-linked immunosorbent assay method, and intracellular reactive oxygen species (ROS) generation was detected using dihydroethidium dye. RESULTS: The blood level of IL-6 was higher in hyperketonemic (HK) diabetic patients than in normoketonemic (NK) diabetic patients (P < 0.05) and normal control subjects (P < 0.05). There was a significant correlation between ketosis and IL-6 levels (r = 0.36, P < 0.04, n = 34) in the blood of diabetic patients. Cell culture studies found that exogenous addition of the ketone body AA, but not BHB, increases IL-6 secretion and ROS generation in U937 cells. N-acetylcysteine (NAC) prevented the IL-6 secretion in acetoacetate-treated U937 monocytes. CONCLUSIONS: This study demonstrates that hyperketonemia increases IL-6 levels in the blood of type 1 diabetic patients and that NAC can inhibit IL-6 secretion by U937 monocytic cells cultured in a ketotic medium.
Assuntos
Acetoacetatos/farmacologia , Diabetes Mellitus Tipo 1/sangue , Cetoacidose Diabética/sangue , Interleucina-6/sangue , Adolescente , Idade de Início , Células Cultivadas , Criança , Diabetes Mellitus Tipo 1/imunologia , Cetoacidose Diabética/imunologia , Hemoglobinas Glicadas/metabolismo , Humanos , Corpos Cetônicos/sangue , Espécies Reativas de Oxigênio/metabolismo , Valores de Referência , Irmãos , Células U937/efeitos dos fármacos , Células U937/metabolismoRESUMO
Hydrogen sulfide (H(2)S) is emerging as a physiological neuromodulator as well as a smooth muscle relaxant. We submit the first evidence that blood H(2)S levels are significantly lower in fasting blood obtained from type 2 diabetes patients compared with age-matched healthy subjects, and in streptozotocin-treated diabetic rats compared with control Sprague-Dawley rats. We further observed that supplementation with H(2)S or an endogenous precursor of H(2)S (l-cysteine) in culture medium prevents IL-8 and MCP-1 secretion in high-glucose-treated human U937 monocytes. These first observations led to the hypothesis that lower blood H(2)S levels may contribute to the vascular inflammation seen in diabetes.