Maria Eliza Jordani de Souza

Effect of fluoxetine on rat liver mitochondria

The in vitro and in vivo effects of fluoxetine (and its active metabolite norfluoxetine) on mitochondrial respiration and F0F1-ATPase were studied, respectively, in mitochondria and submitochondrial particles isolated from rat liver. Fluoxetine in vitro inhibited state 3 mitochondrial respiration for alpha-ketoglutarate and succinate oxidations (50% of effect at 0.25 and 0.35 mM drug concentrations, respectively); stimulated state 4 for succinate; and induced a decrease in the respiratory control ratio (RCR) for both oxidizable substrates. The F0F1-ATPase activity was determined at various pH levels in the absence and presence of Triton X-100. The solubilized form was not affected markedly, but an inhibition, apparently non-competitive, was observed for the membrane-bound enzyme, with 50% of the effect at a 0.06 mM drug concentration in pH 7.4. These results suggest that fluoxetine in vitro acts on F0F1-ATPase through direct interaction with the membrane F0 component (similar to oligomycin), or first with mitochondrial membrane and then affecting F0. A very similar behavior concerning the respiratory parameters and F0F1-ATPase properties was observed with norfluoxetine. The in vivo studies with fluoxetine showed stimulation of mitochondrial respiration in state 4 for alpha-ketoglutarate or succinate oxidations in acute or prolonged treatments (1 hr after a single i.p. dose of 20 mg of drug/kg of body weight, and 22 hr after 12 days of treatment with a daily dose of 10 mg/kg of body weight, respectively), indicating uncoupling of oxidative phosphorylation. Pronounced changes were not observed in the K0.5 values of F0F1-ATPase catalytic sites, but the Vmax decreased during the prolonged treatment. The results show that fluoxetine (as well as norfluoxetine) has multiple effects on the energy metabolism of rat liver mitochondria, being potentially toxic in high doses. The drug effects seem to be a consequence of the drug and/or metabolite solubilization in the inner membrane of the mitochondria.

Biochemical liver function after partial hepatic resection with or without partial hepatic vascular exclusion

PURPOSE The aim of the present study was to assess the advantages and disadvantages of liver vascular partial exclusion (LVPE) (liver dysfunction due to ischemia) during liver resection in patients submitted to partial hepatectomy. METHODS A total of 114 patients were submitted to partial hepatectomy (minor versus major resections) with LPVE being used in 57 of them but not in the remaining 57. Patient age ranged from 35 to 73 years and 57 % were women. Mitochondrial function was assessed 30 minutes after liver resection in the remnant liver and serum aminotransferases were determined before surgery and for seven days postoperatively. LPVE time ranged from 30 to 60 minutes. Data were analyzed statistically by the Student T test (5 % level of significance). RESULTS Mitochondrial function was similar in the minor and major liver resections. The maximum postoperative aminotransferase peak was similar in the groups with and without LPVE. CONCLUSION LPVE did not induce mitochondrial changes in hepatic tissue in either type of surgery, and aminotransferase levels were similar for patients with and without LPVE. Thus, the results show that LPVE is a safe procedure that does not induce the significant changes typical of ischemia and reperfusion in the liver remnant.

Effects of hyperbaric oxygen (HBO), as pre-conditioning in liver of rats submitted to periodic liver ischemia/reperfusion

PURPOSE to assess the effect of hyperbaric oxygen (HBO) as pre-conditioning on periodic liver ischemia/reperfusion injury. METHODS Thirty-six male Wistar rats were divided into 4 groups (SHAM, I/R , HBO-I/R and CONTROL). The surgical technique consisted of total clamping of the hepatic pedicle for 15 min followed by twice repeated reperfusion for 5 min (unclamping). HBO was applied in a collective chamber (simultaneous exposure of 4 rats) directly pressurized with oxygen at 2 ATA for 60 min. Hepatic mitochondrial function was determined using samples of the median lobe obtained after exactly 5 min of reperfusion for the analysis of mitochondrial respiration based on the determination of states 3 and 4, the respiratory control ratio and the transition of mitochondrial permeability (mitochondrial swelling).Data were analyzed by the Mann-Whitney test and the level of significance was set at p < 0.05. RESULTS There was a statistically significant difference (p < 0.05) in state 3 between the CONTROL and I/R and HBO-I/R groups, in state 4 between the CONTROL and I/R and HBO-I/R groups; in respiratory control ratio (RCR) between the CONTROL and I/R and HBO-I/R groups and between the CONTROL and Sham groups, and in mitochondrial swelling between the CONTROL and I/R and HBO-/R groups and between the Sham and I/R and HBO-I/R groups. CONCLUSION In this process of periodic ischemia and reperfusion, hyperbaric pre-conditioning did not improve significantly hepatic mitochondrial function.

Effect of hyperbaric oxygen therapy on liver function during intermittent ischemia

PURPOSE To analyze the effects of hyperbaric oxygen therapy on liver function in rats previously subjected to ischemia and reperfusion. METHODS A randomly distribution of 23 Wistar rats was conducted into three groups: SHAM, animals subjected to surgical stress without restricting blood flow by clamping the hepatic pedicle, IR, rats underwent hepatic vascular occlusion intermittently for two complete cycles of 15 minutes of ischemia followed by 5 min of reperfusion, IR / HBO, rats underwent hepatic pedicle clamping and thereafter exposed to hyperbaric oxygen pressure of 2 absolute atmospheres for 60 minutes. We evaluated liver function through mitochondrial function, determined by the stages 3 and 4 of respiration, respiratory control ratio (RCR) and mitochondrial permeability transition (Swelling). Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also quantified . We analyzed the results using the Mann-Whitney test and were considered significant all results with p <0.05. RESULTS There were significant differences between the results of stage 3 in SHAM vs IR group ; of the stage 4 in the groups IR vs SHAM and SHAM vs IR /HBO; of the Respiratory Control Ratio (RCR) in the group IR vs IR / HBO ; of alanine aminotransferase in the groups IR vs SHAM , SHAM vs IR/HBO and IR vs IR / HBO; aspartate aminotransferase in the groups SHAM vs IR and SHAM vs IR / HBO. CONCLUSION The whole analysis of the mitochondrial function indicators permits us to conclude that the hyperbaric oxygen therapy acted as a protective agent of the mitochondrial function, minimizing the ischemia-reperfusion injury of the hepatic parenchyma.

Hyperbaric oxygen therapy and ischemia and reperfusion: a valuable association to attenuate ischemic lesion and hepatic reperfusion

PURPOSE To investigate the consequences of the association between hyperbaric oxygen therapy and hepatic ischemia / reperfusion. METHODS Wistar rats were divided into three groups: SHAM, rats submitted to surgical stress and anesthetic but not hepatic ischemia or reperfusion, I / R, rats submitted to total hepatic pedicle ischemia for 30 min, followed by 5 min of reperfusion; HBO120, rats submitted to 120 min of hyperbaric oxygen therapy at two absolute atmospheres and immediately after submitted to the experimental protocol of ischemia and reperfusion. The preservation of the hepatic function was evaluated by determining mitochondrial swelling and malondialdehyde tissue level, as well as alanine aminotransferase and aspartate aminotranferase serum levels. The results were analyzed using the Mann-Whitney test and differences were considered significant for p<0.05. RESULTS There were significant differences in values: mitochondrial swelling of the I / R group compared to SHAM and HBO120; malondialdehyde between SHAM vs. I / R, SHAM vs HBO120, and I / R vs HBO120, alanine aminotransferase between SHAM vs. I / R . There was no significant difference between groups in aspartate aminotransferase serum levels. CONCLUSION The association between hyperbaric oxygen therapy and hepatic ischemia and reperfusion process was positive.

Proliferative effect of the aqueous extract of Hyptis pectinata on liver regeneration after partial hepatectomy in rats

PURPOSE This study was carried out to assess the effects of the aqueous extract of Hyptis pectinata leaves on liver regeneration and on serum enzymes (AST, ALT and gamma-GT) after 67% partial hepatectomy in rats. METHODS AST, ALT and gamma-GT, were determined by conventional procedures using a spectrophotometer (Model E2250-CELM). Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen (PCNA). RESULTS Oral pretreatment during 4 days at 100 mg/kg increased liver regeneration index. At 200 mg/kg, AST level was statistically decreased in comparison to the group submitted to distilled water administration. The other enzymes assessed disclosed no difference when all groups were compared. CONCLUSION The present study shows that the aqueous extract of Hyptis pectinata leaves contains some biological active principles that stimulate liver regeneration at 100 mg/kg and cause slight hepatic protection at 200 mg/kg.

Exhaled breath condensate collection for nitrite dosage: a safe and low cost adaptation

PURPOSE Standardization of a simple and low cost technique of exhaled breath condensate (EBC) collection to measure nitrite. METHODS Two devices were mounted in polystyrene boxes filled either with crushed ice/salt crystals or dry ice/crushed ice. Blood samples were stored at -70 degrees C for posterior nitrite dosages by chemiluminescence and the Griess reaction. RESULTS a) The use of crushed ice/dry ice or salt revealed sufficient EBC room air collection, but was not efficient for patients under ventilation support; b) the method using crushed ice/salt collected greater EBC volumes, but the nitrite concentrations were not proportional to the volume collected; c) The EBC nitrite values were higher in the surgical group using both methods; d) In the surgical group the nasal clip use diminished the EBC nitrite concentrations in both methods. CONCLUSIONS The exhaled breath condensate (EBC) methodology collection was efficient on room air breathing. Either cooling methods provided successful EBC collections showing that it is possible to diminish costs, and, amongst the two used methods, the one using crushed ice/salt crystals revealed better efficiency compared to the dry ice method.

Pyruvate kinase activation and lipoperoxidation after selective hepatic ischemia in Wistar rats

PURPOSE Hepatic ischemia and reperfusion can cause several problems in hepatic surgery. The aim of this study was to determine pyruvate kinase activation and lipid peroxidation after hepatic ischemia. METHODS Twenty-four Wistar rats were submitted to 90 minutes of selective liver ischemia and 15 minutes of reperfusion. Twelve animals were submitted to selective liver ischemia and reperfusion (Group A) and the other 12 were submitted to sham operation (Group B). After 15 minutes of reperfusion, the following parameters were measured: mean arterial pressure (MAP), alanine aminotransferase (ALT), glycemia (GLY), hepatic glycogen (GH), pyruvate kinase (PK) activation, hepatic glutathione (GSH) and malondialdehyde (MDA). Analysis of the results were made by the Student t-test and has been considered significant difference for p<0.05. RESULTS A and B were differents for all parameters analized. CONCLUSION The animals of group A showed reperfusion syndrome with a fall in MAP, activation of glycid metabolism through the glycolitic pathway and presence of lipid peroxidation compared to group B.

Efeito da deferoxamina na isquemia e reperfusão do fígado remanescente após ressecção hepática parcial

Particularmente, a utilizacao de varios tipos de drogas que diminuem os efeitos deleterios do binomio isquemia-reperfusao, tem tornado-se foco de varios estudos experimentais visando possiveis aplicacoes clinicas. O objetivo do presente estudo foi avaliar os efeitos da deferoxamina na isquemia e reperfusao sobre o figado remanescente apos resseccao hepatica parcial a 70%, avaliando-se variaveis bioquimicas do sangue: aspartato aminotransferase e alanina aminotransferase;.A amostra de 34 ratos foi dividida em grupos: Grupo HP (n = 8) - submetidos a hepatectomia parcial (HP) a 70%; Grupo HPD (n = 4) - submetidos a administracao de deferoxamina (40 mg/kg) e HP a 70%; Grupo HPI (n = 7) - hepatectomizados (HP a 70%) e submetidos a isquemia (40 minutos); Grupo HPID (n = 7) - semelhante ao anterior, porem recebendo previamente deferoxamina; Grupo C (n = 8) - controle, submetido a operacao simulada para HP a 70%. A analise estatistica entre os diversos grupos foi feita pelos testes de Kruskal - Wallis e de Mann - Whitney, com nivel de significância de 5%. Portanto, houve aumento significativo das aminotransferases nos animais submetidos a hepatectomia e a isquemia. Esse aumento foi inibido pela deferoxamina.

Analysis of 83 consecutive liver transplants performed at a tertiary care reference hospital in the interior of the state of Sao Paulo

PURPOSE To analyze pre-, intra- and immediate postoperative parameters of patients submitted to liver transplantation. METHODS Eighty-three consecutive orthotopic liver transplants performed from January 2009 to July 2011 were analyzed. The patients were divided into 2 groups: A, survivors (MELD between 9 and 60) and B, non-survivors (MELD between 14 and 40), with 30.6% of group A patients being CHILD C, 51℅ CHILD B and 18,4℅ CHILD A. In group B, 32.1℅ of the patients were CHILD C, 42,9℅ CHILD B, and 25℅ CHILD A. All orthotopic liver transplantations were performed using the piggyback technique without a portacaval shunt. Systemic arterial pressure and serum ALT and AST levels were determined preoperatively and 5, 60 and 1440 minutes after arterial graft revascularization. Serum ALT and AST profiles were evaluated for seven days after surgery. RESULTS Systemic arterial blood pressure levels, time of hot and hypothermic ischemia and time of graft implant were statistically similar for the two groups (p>0.05). Serum levels (U/L) of ALT and AST at the 5, 60 and 1440 minute time points after arterial revascularization of the graft were also similar for the two groups studied, as also were the serum ALT and AST profiles. CONCLUSIONS No statistically significant difference in any of the parameters studied was detected between the two groups. Under the conditions of the present study and on the basis of the parameters evaluated, no direct relation was detected between the intraoperative period and the type of patient outcome in the two groups studied.