RESUMO
It has been reported that vitamin D regulates the immune system. However, whether vitamin D repletion modulates inflammatory responses in lymphocytes from dialysis patients is unclear. In the clinical trial, thirty-two (32) dialysis patients with 25 vitamin D ≤ 20ng/mL were randomized to receive either supplementation of cholecalciferol 100,000 UI/week/3 months (16 patients) or placebo (16 patients). In the in vitro study, B and T lymphocytes from 12 healthy volunteers (HV) were incubated with or without uremic serum in the presence or absence of 25 or 1,25 vitamin D. We evaluated the intracellular expression of IL-6, IFN-γ TLR7, TLR9, VDR, CYP27b1 and CYP24a1 by flow cytometry. We observed a reduction in the expression of TLR7, TLR9, INF-γ and CYP24a1 and an increase in VDR and CYP27b1 expression in patients which were supplemented with cholecalciferol, whereas no differences were found in the placebo group. Uremic serum increased the intracellular expression of IL-6, IFN-γ, TLR7, TLR9, VDR, CYP27b1 and CYP24a1. Treatment with 25 or 1,25 vitamin D decreased IL-6 and TLR9. CYP24a1 silencing plus treatment with 25 and/or 1,25 vitamin D had an additional reduction effect on IL-6, IFN-γ, TLR7 and TLR9 expression. This is the first study showing that cholecalciferol repletion has an anti-inflammatory effect and improves vitamin D intracellular regulatory enzymes on lymphocytes from dialysis patients.
Assuntos
25-Hidroxivitamina D3 1-alfa-Hidroxilase/sangue , Colecalciferol/farmacologia , Inflamação/prevenção & controle , Uremia/enzimologia , Vitamina D3 24-Hidroxilase/sangue , Vitamina D/metabolismo , Estudos de Casos e Controles , Citocinas/sangue , Método Duplo-Cego , Humanos , Inflamação/complicações , Mediadores da Inflamação/sangue , Projetos Piloto , Placebos , Receptores de Calcitriol/sangue , Receptores Toll-Like/sangue , Uremia/complicaçõesRESUMO
Encephalopathy may accompany acute or chronic renal failure, and the mechanisms responsible for neurological complications in patients with renal failure are poorly known. Considering that creatine kinase (CK) is important for brain energy homeostasis and is inhibited by free radicals, and that oxidative stress is probably involved in the pathogenesis of uremic encephalopathy, we measured CK activity (hippocampus, striatum, cerebellum, cerebral cortex and prefrontal cortex) in brain if rats submitted to renal ischemia and the effect of administration of antioxidants (N-acetylcysteine, NAC and deferoxamine, DFX) on this enzyme. We verified that CK activity was not altered in cerebellum and striatum of rats. CK activity was inhibited in prefrontal cortex and hippocampus of rats 12h after renal ischemia. The treatment with antioxidants prevented such effect. Cerebral cortex was also affected, but in this area CK activity was inhibited 6 and 12h after renal ischemia. Moreover, only NAC or NAC plus DFX were able to prevent the inhibition on the enzyme. Although it is difficult to extrapolate our findings to the human condition, the inhibition of brain CK activity after renal failure may be associated to neuronal loss and may be involved in the pathogenesis of uremic encephalopathy.
Assuntos
Antioxidantes/farmacologia , Encefalopatias Metabólicas/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Creatina Quinase/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Uremia/tratamento farmacológico , Acetilcisteína/farmacologia , Acetilcisteína/uso terapêutico , Animais , Antioxidantes/uso terapêutico , Encéfalo/enzimologia , Encéfalo/fisiopatologia , Encefalopatias Metabólicas/enzimologia , Encefalopatias Metabólicas/fisiopatologia , Creatina Quinase/metabolismo , Desferroxamina/farmacologia , Desferroxamina/uso terapêutico , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Isquemia/complicações , Nefropatias/complicações , Masculino , Degeneração Neural/tratamento farmacológico , Degeneração Neural/enzimologia , Degeneração Neural/fisiopatologia , Estresse Oxidativo/fisiologia , Ratos , Ratos Wistar , Frações Subcelulares , Fatores de Tempo , Resultado do Tratamento , Uremia/enzimologia , Uremia/fisiopatologiaRESUMO
The results of the studies reported here demonstrate the cardiac non-haematopoietic effect of erythropoietin, providing a new physiological function of the hormone. We demonstrate that myocardium from rat with chronic renal failure (CRF) showed an abnormal response to ouabain associated with an inhibition of cardiac Na+/K+/ATPase activity and with a decrease in the high affinity 3H-ouabain binding sites. The extent to which both actions were improved with the recombinant human erythropoietin (rHuEpo) treatment suggests that the lack of the hormone is responsible for this phenomenon. The fact is that neither contractile nor enzymatic action of rHuEpo was accompanied with the improvement of the functional renal and haematologic parameters, indicating a primary effect on myocardial contractile function of rHuEpo, independent of the anaemic and uraemic state of the animal. The reason why erythropoietin is able to modulate directly the cardiac Na+/K+ pump makes it possible to conclude that the lack of erythropoietin in CRF may be at least in part responsible for the inhibition of cardiac enzymes, altering the contractile behaviour of the heart.
Assuntos
Anemia/tratamento farmacológico , Cardiotônicos/farmacologia , Eritropoetina/farmacologia , Ouabaína/farmacologia , Uremia/tratamento farmacológico , 4-Nitrofenilfosfatase/metabolismo , Anemia/enzimologia , Animais , Relação Dose-Resposta a Droga , Coração/efeitos dos fármacos , Humanos , Falência Renal Crônica/tratamento farmacológico , Falência Renal Crônica/enzimologia , Masculino , Ratos , Ratos Wistar , Proteínas Recombinantes/farmacologia , Uremia/enzimologiaRESUMO
We studied in vivo biochemical effects of insulin in the skeletal muscle of chronically uremic and control rats. The rate of disappearance of blood glucose (determined with a short intravenous test) was reduced by 38% in uremia (p less than 0.05). Intraperitoneal treatment with insulin plus glucose for 30 min caused a 3-fold increase in the activity of insulin receptor tyrosine kinase in the skeletal muscle of both rat groups. Conversely, pyruvate dehydrogenase activity increased by 115% in controls but only by 26% in uremics (p less than 0.01). Exercise (swimming for 30 min) increased muscle pyruvate dehydrogenase activity approximately 2-fold in both groups of animals. These experiments show that in uremic rats, insulin binds normally to its muscle receptors and adequately activates receptor tyrosine kinase but fails to activate an otherwise responsive pyruvate dehydrogenase.
Assuntos
Insulina/farmacologia , Falência Renal Crônica/enzimologia , Músculos/enzimologia , Proteínas Tirosina Quinases/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Receptor de Insulina/metabolismo , Uremia/enzimologia , Animais , Glicemia/metabolismo , Ativação Enzimática , Teste de Tolerância a Glucose , Insulina/análogos & derivados , Insulina/metabolismo , Falência Renal Crônica/sangue , Masculino , Músculos/efeitos dos fármacos , Músculos/fisiopatologia , Ratos , Ratos Endogâmicos , Receptor de Insulina/isolamento & purificação , Valores de Referência , Uremia/sangueAssuntos
Azatioprina/uso terapêutico , Eritrócitos/enzimologia , Transplante de Rim/imunologia , Metiltransferases/sangue , Adulto , Azatioprina/efeitos adversos , Ciclosporina/uso terapêutico , Feminino , Humanos , Transplante de Rim/fisiologia , Leucopenia/induzido quimicamente , Masculino , Prednisolona/uso terapêutico , Valores de Referência , Diálise Renal , Uremia/sangue , Uremia/enzimologia , Uremia/terapiaRESUMO
We measured phospholipase A2 (PLA2; EC 3.1.1.4) activity in normal and uremic plasma, using [1-14C]oleate-labeled autoclaved Escherichia coli as substrate. Hydrolysis of bacterial phospholipid by crude plasma from both groups was optimal at pH 5.5, was specific for the 2-acyl position of phospholipids, and had an absolute requirement for calcium. Activity was greatest in the presence of added Ca2+, 5 mmol/L, but this increase was inhibited by several divalent cations (Mg2+, Zn2+, Cu2+, Ba2+, Co2+, Pb2+, Fe2+) and by Fe3+. PLA2 activity was also inhibited by heparin at acid and alkaline pH, normal plasma being more sensitive than uremic plasma to this inhibition. Enzyme activity in undiluted plasma was eightfold greater in uremic than in normal plasma. Dilution of plasma by two to fourfold increased the total activity of both normal and uremic plasma. However, the relative differences in total activity between the groups remained constant (eight- to 11-fold). The cause and consequences of the increased PLA2 activity in uremia remain to be established.
Assuntos
Fosfolipases A/sangue , Fosfolipases/sangue , Uremia/enzimologia , Cloreto de Cálcio , Cromatografia em Camada Fina , Ativação Enzimática/efeitos dos fármacos , Escherichia coli , Heparina/farmacologia , Humanos , Hidrólise , Metais/farmacologia , Ácido Oleico , Ácidos Oleicos , Fosfolipases A/antagonistas & inibidores , Fosfolipases A2 , Contagem de Cintilação , Uremia/sangueRESUMO
A variant form of hypoxanthine-guanine phosphoribosyl transferase has been found in a neurologically normal pediatric patient who presented with hematuria an episodes of oliguria and azotemia. The level of erythrocyte enzyme activity was 3% of normal. Electrophoretic mobility was more rapid than normal. The Km for hypoxanthine was approximately ten times normal. Immunochemical analysis indicated that the variant enzyme cross reacted with antibody to normal HPRT. A system is described for the systematic characterization of a variant HPRT.