Preconditioning with a novel metallopharmaceutical NO donor in anesthetized rats subjected to brain ischemia/reperfusion.

Rut-bpy is a novel nitrosyl-ruthenium complex releasing NO into the vascular system. We evaluated the effect of Rut-bpy (100 mg/kg) on a rat model of brain stroke. Forty rats were assigned to four groups (Saline solution [SS], Rut-bpy, SS+ischemia-reperfusion [SS+I/R] and Rut-bpy+ischemia-reperfusion [Rut-bpy+I/R]) with their mean arterial pressure (MAP) continuously monitored. The groups were submitted (SS+I/R and Rut-bpy+I/R) or not (SS and Rut-bpy) to incomplete global brain ischemia by occlusion of the common bilateral carotid arteries during 30 min followed by reperfusion for further 60 min. Thirty minutes before ischemia, rats were treated pairwise by intraperitoneal injection of saline solution or Rut-bpy. At the end of experiments, brain was removed for triphenyltetrazolium chloride staining in order to quantify the total ischemic area. In a subset of rats, hippocampus was obtained for histopathology scoring, nitrate and nitrite measurements, immunostaining and western blotting of the nuclear factor- κB (NF-κB). Rut-bpy pre-treatment decreased MAP variations during the transition from brain ischemia to reperfusion and decreased the fractional injury area. Rut-bpy pre-treatment reduced NF-κB hippocampal immunostaining and protein expression with improved histopathology scoring as compared to the untreated operated control. In conclusion, Rut-bpy improved the total brain infarction area and hippocampal neuronal viability in part by inhibiting NF-κB signaling and helped to stabilize the blood pressure during the transition from ischemia to reperfusion.

L-alanyl-glutamine dipeptide pretreatment attenuates ischemia-reperfusion injury in rat testis.

PURPOSE: To investigate the effect of alanyl-glutamine dipeptide (L-Ala-Gln) pre-treatment on ischemia-reperfusion (I/R) injury after unilateral testicular torsion-detorsion in a comparative controlled experiment. METHODS: Forty-eight rats (150-200 g) randomly distributed into 4 groups (n=12), and distributed in 2 subgroups (n=6) each, were treated with saline 2.0 ml (G-1, G-3) or L-Ala-Gln 20%, 0.75g/kg dissolved in saline (total volume 2.0 ml) administered in the left saphenous vein 30 minutes before ischemia. Anesthetized rats were subjected to I/R induced by torsion (720°) of the right spermatic cord lasting 1h (G-1, G-2) or 3 hours (G-3, G4). Anesthesia was again applied at the end of ischemia time (T-0) for testis detorsion and 6 hours later (T-6) for orchiectomy. All operations were performed on the right testes through transverse scrotal incisions. Right orchiectomy was carried out at the end of ischemia (T-0), and 6 hours later (T-6) to evaluate the concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) in the testis. RESULTS: Pretreatment with L-Ala-Gln reduced MDA contents in rat testis at the end of ischemia lasting 3 hours. There was significant increase of GSH levels in T-6 time-point after 1 hour of ischemia. GSH levels also increased in T-0 and T-6 time-points in rats subjected to ischemia for 3 hours. CONCLUSION: L-Ala-Gln administered before torsion/detorsion of the spermatic cord decreases lipid peroxidation during ischemia and protects the testis from oxidative stress by upregulating GSH levels during reperfusion.

Effect of glutamine on the mRNA level of key enzymes of malate-aspartate shuttle in the rat intestine subjected to ischemia reperfusion.

PURPOSE: To determine the effects of oral L-glutamine (L-Gln) and the dipeptide L-alanyl-glutamine (L-Ala-Gln) upon the activity of the malate-aspartate shuttle in the rat distal small intestine following ischemia and reperfusion. METHODS: Seventy-two Wistar rats (350-400g), were randomized in 2 groups (n = 36): group S (Sham) and Group T (Treatment) and divided into 12 subgroups (n = 6): A-A6, and B1-B6. The subgroups A1-A3 were subjected to sham procedures at 30 and 60 minutes. Thirty minutes before the study, rats were treated with calcium caseinate, 0.5g/Kg (subgroups A1, A4, B1, B4), L-Gln, 0.5g / kg (subgroups A2, A5, B2 and B5) or L-Ala-Gln, 0.75g/Kg (subgroups A3, A6, B3, B6), administered by gavage. Ischemia was achieved by clamping the mesenteric vessels, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. Samples were collected 30 and 60 minutes after start of the study for real-time PCR assay of malate dehydrogenases (MDH1-2) and aspartate-aminotransferases (GOT1-2) enzymes. RESULTS: Tissue MDH and GOT mRNA expression in intestinal samples from rats preconditioned with either L-Gln or L-Ala-Gln showed no significant differences both during ischemia and early reperfusion. CONCLUSION: Activation of the malate-aspartate shuttle system appears not to be the mechanism of glutamine-mediated elevation of glucose oxidation in rat intestine during ischemia/reperfusion injury.

Metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for congenital heart disease.

PURPOSE: To evaluate the metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for correction of congenital heart disease. METHODS: Twenty children with acyanotic congenital heart disease, scheduled for elective cardiac surgery with cardiopulmonary bypass, age range 1 day to 14 years were randomly assigned to 2 groups: Group GP, programmed to receive total intravenous anesthesia with propofol and group GS scheduled to use balanced anesthesia with sevoflurane. Exclusion criteria were cyanotic heart disease or complex, association with other malformations, severe systemic diseases, infection or children undergoing treatment and palliative or emergency surgery. Blood samples were collected at three different time-points: T0, after radial artery cannulation, T1, 30 minutes after cardiopulmonary bypass (CPB) launch and T2, at the end of procedure. Parameters analyzed included thiobarbituric acid-reactive substance (TBARS), glutathione (GLN), lactate and pyruvate plasmatic concentrations. RESULTS: TBARS, GSH, lactate and pyruvate concentrations did not change significantly by Friedman´s test. Lactate/pyruvate ratio (L/P) was >10 in both groups. There was a moderate Pearson correlation for TBARS, in T1 (r=0.50; p=0.13) e T2 (r=0.51;p=0.12). Pearson correlation was high between groups during CPB (T1) for lactate (r=0.68; p=0.02), pyruvate (r=0.75; p=0.01) and L/P ratio (r=0.83; p=0.003). CONCLUSION: Anesthetic techniques investigated in this study showed a similar pattern, with no increase in metabolic substrates and oxidative stress during surgical correction of congenital heart defects in non-cyanotic children.

Preoperative glutamine infusion improves glycemia in heart surgery patients.

PURPOSE: To evaluate the effects of pre-operative L-alanyl-glutamine (L-Ala-Gln) on blood glucose control in patients with coronary obstruction, selected for myocardial revascularization. METHODS: Twenty-two patients (63±8 years) were randomly assigned to receive 250 ml of L-Ala-Gln 20% plus saline 750 ml (Group L- Ala-Gln, n=11) or saline 1000 ml (Group Saline, n=11) over 3 hours before operation. Pre-operative blood samples were collected 3h before (T-1) and at the beginning of the surgical procedure (T-2). Intra-operative samples were collected immediately before the start (T-3) and the end of extra-corporeal perfusion (T- 4). Post-operative samples were collected 12h (T-12) and 24h later (T-24). RESULTS: Glycemia decreased significantly in L-Ala-Gln treated patients during the intraoperative period. The same effect did not occur in saline patients. As the rate of insulin infusion, administered routinely to patients undergoing surgery with extracorporeal circulation was constant in both groups during surgery, the reduction of blood glucose in group L-Ala-Gln does not seem to be related to exogenous insulin. CONCLUSION: Pre-operative use of L-Ala-Gln improves glycemic control in patients with coronary artery occlusion, submitted to myocardial revascularization.

L-Alanyl-Glutamine dipeptide pretreatment attenuates ischemia-reperfusion injury in rat testis / Pré-tratamento com o dipeptídeo L-Alanil-glutamina atenua a lesão por isquemia e reperfusão no testículo do rato

PURPOSE: To investigate the effect of alanyl-glutamine dipeptide (L-Ala-Gln) pre-treatment on ischemia-reperfusion (I/R) injury after unilateral testicular torsion-detorsion in a comparative controlled experiment. METHODS: Forty-eight rats (150-200 g) randomly distributed into 4 groups (n=12), and distributed in 2 subgroups (n=6) each, were treated with saline 2.0 ml (G-1, G-3) or L-Ala-Gln 20 percent, 0.75g/kg dissolved in saline (total volume 2.0 ml) administered in the left saphenous vein 30 minutes before ischemia. Anesthetized rats were subjected to I/R induced by torsion (720°) of the right spermatic cord lasting 1h (G-1, G-2) or 3 hours (G-3, G4). Anesthesia was again applied at the end of ischemia time (T-0) for testis detorsion and 6 hours later (T-6) for orchiectomy. All operations were performed on the right testes through transverse scrotal incisions. Right orchiectomy was carried out at the end of ischemia (T-0), and 6 hours later (T-6) to evaluate the concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) in the testis. RESULTS: Pretreatment with L-Ala-Gln reduced MDA contents in rat testis at the end of ischemia lasting 3 hours. There was significant increase of GSH levels in T-6 time-point after 1 hour of ischemia. GSH levels also increased in T-0 and T-6 time-points in rats subjected to ischemia for 3 hours. CONCLUSION: L-Ala-Gln administered before torsion/detorsion of the spermatic cord decreases lipid peroxidation during ischemia and protects the testis from oxidative stress by upregulating GSH levels during reperfusion.

OBJETIVO: Investigar o efeito do pré-tratamento com o dipeptídeo L-alanil-glutamina (L-Ala-Gln) sobre a lesão de isquemia e reperfusão (I/R), induzida por torção/destorção do testículo em um experimento controlado e comparativo. MÉTODOS: Quarenta e oito ratos (150-200 g) divididos em quatro grupos (n=12) e distribuídos em dois subgrupos (n = 6) cada, foram tratados com 2,0 ml de solução salina (G-1, G-3 ) ou L-Ala-Gln 20 por cento, 0,75g/kg dissolvida em solução salina (volume total de 2,0 ml), administrada na veia safena 30 minutos antes da isquemia. Ratos anestesiados foram submetidos à torção (720°) do cordão espermático direito durante 1h (G-1, G-2) ou 3 horas (G-3, G4) para indução da I/R. A anestesia foi reaplicada no final do tempo de isquemia (T-0) para destorção do testículo e 6 horas depois (T-6) para orquiectomia. Todas as operações foram realizadas nos testículos direitos através de incisões escrotais. Orquiectomia direita foi realizada no final de isquemia (T-0), e seis horas depois (T-6) para avaliar as concentrações de malondialdeído (MDA) e glutationa reduzida (GSH) no testículo. RESULTADOS: O pré-tratamento com L-Ala-Gln reduziu os níveis de MDA no testículo de ratos no final da isquemia (3 horas). Entretanto os níveis de GSH aumentaram significativamente no T-6 após 1 hora de isquemia e também no T-0 e T-6 em ratos submetidos à isquemia por 3 horas. CONCLUSÃO: L-Ala-Gln administrada antes da torção/destorção do cordão espermático diminui a peroxidação lipídica na isquemia e protege o testículo contra o estresse oxidativo, promovendo aumento dos níveis de GSH durante a reperfusão.

Effect of glutamine on the mRNA level of key enzymes of malate-aspartate shuttle in the rat intestine subjected to ischemia reperfusion / Efeito da glutamina sobre o nível de RNA Mensageiro das enzimas-chave do ciclo malato-aspartato no intestino de ratos submetidos à isquemia e reperfusão

PURPOSE: To determine the effects of oral L-glutamine (L-Gln) and the dipeptide l-alanyl-glutamine (L-Ala-Gln) upon the activity of the malate-aspartate shuttle in the rat distal small intestine following ischemia and reperfusion. METHODS: Seventy-two Wistar rats (350-400g), were randomized in 2 groups (n = 36): group S (Sham) and Group T (Treatment) and divided into 12 subgroups (n = 6): A-A6, and B1-B6. The subgroups A1-A3 were subjected to sham procedures at 30 and 60 minutes. Thirty minutes before the study, rats were treated with calcium caseinate, 0.5g/Kg (subgroups A1, A4, B1, B4), L-Gln, 0.5g / kg (subgroups A2, A5, B2 and B5) or L-Ala-Gln, 0.75g/Kg (subgroups A3, A6, B3, B6), administered by gavage. Ischemia was achieved by clamping the mesenteric vessels, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. Samples were collected 30 and 60 minutes after start of the study for real-time PCR assay of malate dehydrogenases (MDH1-2) and aspartate-aminotransferases (GOT1-2) enzymes. RESULTS: Tissue MDH and GOT mRNA expression in intestinal samples from rats preconditioned with either L-Gln or L-Ala-Gln showed no significant differences both during ischemia and early reperfusion. CONCLUSION: Activation of the malate-aspartate shuttle system appears not to be the mechanism of glutamine-mediated elevation of glucose oxidation in rat intestine during ischemia/reperfusion injury.

OBJETIVO: Determinar os efeitos da administração oral de L-glutamina (L-Gln) e do dipeptídeo L-alanil-glutamina (L-Ala-Gln) sobre a atividade do ciclo malato-aspartato no intestino delgado distal de ratos após isquemia/reperfusão. MÉTODOS: Setenta e dois ratos Wistar (350-400g) foram randomizados em 2 grupos (n = 36): T grupo S (Sham) e grupo (Tratamento) e distribuídos em 12 subgrupos (n = 6): A-A6, e B1-B6. Os subgrupos A1-A3 foram submetidos a procedimentos "sham" aos 30 e 60 minutos. Trinta minutos antes do estudo, os ratos foram tratados com caseinato de cálcio, 0,5 g/kg (subgrupos A1, A4, B1 e B4), L-Gln, 0,5 g/kg (subgrupos A2, A5, B2 e B5) ou L-Ala -Gln, 0,75g/kg (subgrupos A3, A6, B3, B6), administrado por gavagem. A isquemia foi obtida por pinçamento dos vasos mesentéricos, delimitando um segmento do intestino cinco centímetros de comprimento e 5 cm da válvula ileocecal. Amostras foram coletadas aos 30-60 minutos para ensaio de PCR em tempo real das enzimas malato desidrogenases (MDH1-2), aspartato-aminotransferase (GOT1-2). RESULTADOS: A expressão de MDH e GOT mRNA nas amostras provenientes do intestino delgado de ratos pré-condicionados com L-Gln ou L-Ala-Gln não apresentou diferenças significativas, tanto durante a isquemia como na fase inicial de reperfusão. CONCLUSÃO: Ativação do ciclo malato-aspartato não parece ser o mecanismo de elevação glutamina-mediada da oxidação da glicose no intestino de ratos durante a isquemia / reperfusão.

Metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for congenital heart disease / Efeitos metabólicos e oxidativos do sevoflurano e do propofol em crianças portadoras de cardiopatia congênita submetidas à cirurgia

PURPOSE: To evaluate the metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for correction of congenital heart disease. METHODS: Twenty children with acyanotic congenital heart disease, scheduled for elective cardiac surgery with cardiopulmonary bypass, age range 1 day to 14 years were randomly assigned to 2 groups: Group GP, programmed to receive total intravenous anesthesia with propofol and group GS scheduled to use balanced anesthesia with sevoflurane. Exclusion criteria were cyanotic heart disease or complex, association with other malformations, severe systemic diseases, infection or children undergoing treatment and palliative or emergency surgery. Blood samples were collected at three different time-points: T0, after radial artery cannulation, T1, 30 minutes after cardiopulmonary bypass (CPB) launch and T2, at the end of procedure. Parameters analyzed included thiobarbituric acid-reactive substance (TBARS), glutathione (GLN), lactate and pyruvate plasmatic concentrations. RESULTS: TBARS, GSH, lactate and pyruvate concentrations did not change significantly by Friedman´s test. Lactate/pyruvate ratio (L/P) was >10 in both groups. There was a moderate Pearson correlation for TBARS, in T1 (r=0.50; p=0.13) e T2 (r=0.51;p=0.12). Pearson correlation was high between groups during CPB (T1) for lactate (r=0.68; p=0.02), pyruvate (r=0.75; p=0.01) and L/P ratio (r=0.83; p=0.003). CONCLUSION: Anesthetic techniques investigated in this study showed a similar pattern, with no increase in metabolic substrates and oxidative stress during surgical correction of congenital heart defects in non-cyanotic children.

OBJETIVO: Avaliar os efeitos metabólicos e oxidativos da anestesia com sevoflurano ou propofol em crianças portadoras de cardiopatia congênita, submetidas à cirurgia eletiva. MÉTODOS: Vinte crianças com cardiopatia congênita acianótica, agendadas para a cirurgia cardíaca eletiva com circulação extracorpórea (CEC), idades 1 dia-14 anos, foram distribuídas aleatoriamente em dois grupos: Grupo GP (anestesia venosa total com propofol) e grupo GS (anestesia balanceada com sevoflurano). Critérios de exclusão foram: doença cardíaca cianótica ou complexa, associação com outras malformações, doença sistêmica grave, infecção ou crianças submetidas a tratamento e cuidados paliativos ou cirurgia de emergência. Amostras de sangue foram coletadas em três horários diferentes: T0, após a canulação da artéria radial, T1, 30 minutos após o início da CEC e T2, no final do procedimento. Parâmetros analisados: substâncias reativas ao ácido tiobarbitúrico (TBARS), glutationa (GLN), lactato e piruvato. RESULTADOS: As concentrações de TBARS, GSH, lactato e piruvato não foram diferentes (teste de Friedman). A razão Lactato/piruvato (L/P) foi >10 em ambos os grupos. Houve uma correlação de Pearson moderada no TBARS, em T1 (r = 0,50, p = 0,13) e T2 (r = 0,51, p = 0,12). A correlação de Pearson foi alta entre os grupos durante a CEC (T1) para lactato (r=0,68, p=0,02), piruvato (r=0,75, p=0,01) e relação L/P (r =0,83, p=0,003). CONCLUSÃO: As técnicas anestésicas investigadas mostraram um padrão semelhante, sem aumento de substratos metabólicos ou do estresse oxidativo durante a correção cirúrgica de cardiopatias congênitas em crianças acianóticas.

Preoperative glutamine infusion improves glycemia in heart surgery patients / Infusão pré-operatória de glutamina melhora a glicemia em pacientes submetidos à cirurgia cardíaca

PURPOSE: To evaluate the effects of pre-operative L-alanyl-glutamine (L-Ala-Gln) on blood glucose control in patients with coronary obstruction, selected for myocardial revascularization. METHODS: Twenty-two patients (63±8 years) were randomly assigned to receive 250ml of L-Ala-Gln 20 percent plus saline 750 ml (Group L- Ala-Gln, n=11) or saline 1000 ml (Group Saline, n=11) over 3 hours before operation. Pre-operative blood samples were collected 3h before (T-1) and at the beginning of the surgical procedure (T-2). Intra-operative samples were collected immediately before the start (T-3) and the end of extra-corporeal perfusion (T- 4). Post-operative samples were collected 12h (T-12) and 24h later (T-24). RESULTS: Glycemia decreased significantly in L-Ala-Gln treated patients during the intraoperative period. The same effect did not occur in saline patients. As the rate of insulin infusion, administered routinely to patients undergoing surgery with extracorporeal circulation was constant in both groups during surgery, the reduction of blood glucose in group L-Ala-Gln does not seem to be related to exogenous insulin. CONCLUSION: Pre-operative use of L-Ala-Gln improves glycemic control in patients with coronary artery occlusion, submitted to myocardial revascularization.

OBJETIVO: Avaliar os efeitos do uso pré-operatório da L-alanil-glutamina (L-Ala-Gln) no controle glicêmico em pacientes, selecionados para a revascularização do miocárdio. MÉTODOS: Vinte e dois pacientes cardiopatas (63±8 anos) foram randomizados para receber 250 ml de L-Ala-Gln 20 por cento em 750 ml de solução salina (Grupo L-Ala-Gln, n=11) ou soro fisiológico 1000 ml (Grupo Salina, n=11). Amostras de sangue foram coletadas no pré-operatório, três horas antes (T-1: basal) e no início do procedimento cirúrgico (T-2); imediatamente antes do início (T-3) e no final da perfusão extra-corpórea (T-4); 12h (T-12) e 24h após a conclusão do procedimento. As infusões, com duração de 3 horas, foram iniciadas 3 h antes do procedimento operatório. RESULTADOS: Houve redução significativa da glicemia nos pacientes tratados com L-Ala-Gln durante o período intra-operatório (T-3 e T-4). O mesmo efeito não ocorreu nos pacientes do grupo salina. Como a taxa de infusão de insulina, administrada rotineiramente aos pacientes submetidos à cirurgia com circulação extracorpórea, foi constante em ambos os grupos durante o período intra-operatório, a redução da glicemia no grupo L-Ala-Gln não parece estar relacionada à insulina exógena. CONCLUSÃO: O uso pré-operatório de L-Ala-Gln melhora o controle glicêmico em pacientes com obstrução coronariana, submetidos à revascularização miocárdica.