Prophylactic Use of Laser Light and Methylene Blue on Ischemia and Liver Reperfusion Injury

OBJECTIVE

This study aimed to evaluate the effect of hepatic preconditioning with laser light in the presence of methylene blue (MB) in the liver ischemia-reperfusion injury process.

METHOD

Forty male Wistar rats were divided into 8 experimental groups (n = 5). Saline (.5 mL) or MB (15 mg/kg) was injected intravenously (inferior vena cava). After 2 minutes, 660 nm laser light was applied at a dose of 112.5 DE. Fifteen minutes after the application of saline or MB, 1 hour partial ischemia followed by 15 minutes of reperfusion was applied when the rats were sacrificed. The mitochondrial function parameters (O₂ consumption rates in states 3 and 4 and the respiratory control ratio), osmotic swelling, and determination of malondialdehyde were evaluated. Hepatic function was studied using the serum determination of the alanine aminotransferase and aspartate aminotransferase enzymes.

RESULTS AND CONCLUSIONS

MB therapy alone showed the capacity of preserving the rate of oxygen consumption in the mitochondrial respiratory state of the group submitted to ischemia compared to the sham group. However, when combined with low-intensity laser therapy, it failed to replicate the relevant protective effects in relation to oxidative phosphorylation or the mitochondrial membrane ischemia/reperfusion injury. Whether or not MB was combined with laser treatment, it was shown to be efficient in reducing oxidative stress. In relation to alanine aminotransferase enzymes, whether or not laser treatment was combined with MB had a protective effect on the hepatic lesion, whereas in relation to aspartate aminotransferase enzymes only laser treatment was able to provide this protection.

Evaluation of Lung Function in Liver Transplant Candidates

INTRODUCTION

A wide variety of pulmonary conditions are found in cirrhotic patients and may compromise the pleura, diaphragm, parenchyma, and pulmonary vasculature, influencing the results of liver transplantation.

OBJECTIVE

To evaluate the pulmonary function (lung capacities, volumes, and gasometric study) of patients with liver cirrhosis awaiting liver transplantation.

PATIENTS AND METHODS

Cirrhotic patients, subdivided into 3 groups stratified by liver disease severity using the Child-Pugh-Turcotte score, were compared with a control group of healthy volunteers. In spirometry, the parameters evaluated were total lung capacity, forced volume in the first second, and the relationship between forced volume in the first minute and forced vital capacity. Blood gas analysis was performed. In the control group, arterial oxygenation was evaluated by peripheral oxygen saturation by pulse oximetry.

RESULTS

Of the 55 patients (75% men, 51 ± 12.77 years), 11 were Child A (73% men, 52 ± 14.01 years), 23 were Child B (75% men, 51 ± 12.77 years), and 21 were Child C (95% men, 50 ± 12.09 years). The control group had 20 individuals (50% men, 47 ± 8.15 years). Pulmonary capacities and volumes by the parameters evaluated were within the normal range. Arterial blood gas analysis detected no hypoxemia, but a tendency to low partial gas pressure was noted.

CONCLUSION

In this population of cirrhotic patients the parameters of spirometry were normal in relation to the lung capacities and volumes in the different groups. No hypoxemia was detected, but a tendency to hypocapnia in the blood gas was noted.

A new formula as a predictive score of post-liver transplantation outcome: postoperative MELD-lactate

INTRODUCTION

Liver transplantation (OLT) involves a 5% to 10% 30-day mortality rate. Multiple scores have been used as predictors of early postoperative mortality, such as the original Model for End-stage Liver Disease (MELD) and MELD sodium. Investigations have been conducted over the last 5 years to find new predictors of early post-OLT mortality.

OBJECTIVE

The aim of this study was to develop a new mathematical model to predict the individual chance of 30-day mortality after OLT.

METHODS

The study was conducted on 58 patients submitted to OLT at the University Hospital, between October 2008 and March 2012. The 29 latest survivor and 29 latest nonsurvivor cases were selected. Arterial blood sodium, lactate, international normalized ratio, total bilirubin, and creatinine values were determined 1 hour after the end of surgery. The MELD original equation, MELD sodium, and new MELD lactate were also elaborated. The results were analyzed by the Mann-Whitney and Wilcoxon tests. The level of significance was set at .05.

RESULTS

The new formula elaborated was as follows: MELD lactate = 5.68 × loge (lactate) + 0.64 × (Original MELD) + 2.68. The MELD lactate values were significantly higher than the MELD sodium and original MELD values (P < .05). The area under the receiver operating characteristic curve of MELD lactate in predicting the outcome of patients submitted to OLT was 0.80, as opposed to 0.71 for the original MELD and 0.72 for MELD sodium (P < .05).

CONCLUSION

The postoperative MELD lactate score proved to be more specific and sensitive than the original MELD and MELD sodium as a predictive model of the outcome of patients submitted to OLT.

Evaluation of oxidative stress in the late postoperative stage of liver transplantation

INTRODUCTION

Liver transplant recipients are at an increased oxidative stress risk due to pre-existing hepatic impairment, ischemia-reperfusion injury, immunosuppression, and functional graft rejection. This study compared the oxidative status of healthy control subjects, patients with liver cirrhosis on the list for transplantation, and subjects already transplanted for at least 12 months.

PATIENTS AND METHODS

Sixty adult male patients, aged between 27 and 67 years, were subdivided into 3 groups: a control group (15 healthy volunteers), a cirrhosis group (15 volunteers), and a transplant group (30 volunteers). Oxidative stress was evaluated by activity of reduced glutathione, malondialdehyde, and vitamin E.

RESULTS

There was a significant difference (P < .01) in the plasma concentration of reduced glutathione in the 3 groups, with the lowest values observed in the transplanted group. The malondialdehyde values differed significantly (P < .01) among the 3 groups, with the transplanted group again having the lowest concentrations. The lowest concentrations of vitamin E were observed in patients with cirrhosis compared with control subjects, and there was a significant correlation (P < .05) among the 3 groups. No correlations were found between reduced glutathione and vitamin E or between vitamin E and malondialdehyde. However, there were strong correlations between plasma malondialdehyde and reduced glutathione in the 3 groups: control group, r = 0.9972 and P < .0001; cirrhotic group, r = 0.9765 and P < .0001; and transplanted group, r = 0.8981 and P < .0001.

CONCLUSIONS

In the late postoperative stage of liver transplantation, oxidative stress persists but in attenuated form.

The 14bp-deletion allele in the HLA-G gene confers susceptibility to the development of hepatocellular carcinoma in the Brazilian population

Human leukocyte antigen-G (HLA-G) is a nonclassical HLA class I molecule involved in tumor escape mechanisms. Considering that the HLA-G 14bp insertion/deletion polymorphism is located at the 3' untranslated region (3'UTR) in exon 8, and since it has been associated with the magnitude of HLA-G production, we studied the association of 14bp insertion/deletion polymorphism with the risk of developing hepatocellular carcinoma (HCC). A total of 109 HCC patients followed at the University Hospital, Faculty of Medicine of Ribeirão Preto, São Paulo, Brazil, and 202 healthy controls from the same geographic area were genotyped for the 14bp insertion/deletion polymorphism using polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis. Compared to controls, the frequency of the 14bp deletion allele was overrepresented in HCC patients (65% versus 56%, respectively, P = 0.0326). The 14bp deletion conferred an odds ratio (OR) of 1.46 [95% confidence interval (CI): 1.04-2.05]. Similarly, the deletion/deletion genotype was marginally overrepresented in HCC patients (45% versus 35% in controls, P = 0.0871), conferring an OR of 1.54 (95% CI: 0.96-2.48). The frequencies of the deletion/insertion or insertion/insertion genotypes observed in patients were not statistically different from those observed in controls (P > 0.05). Our results suggest that the 14bp-deletion allele in HLA-G gene is associated with HCC susceptibility in a Brazilian population.

Liver mitochondrial function in familial amyloidotic polyneuropathy

The objective of the present study was to analyze hepatic mitochondrial function in patients with familial amyloidotic polyneuropathy (FAP) undergoing cadaveric donor orthotopic liver transplantation. From February 2005 to May 2007, eight patients with FAP, ranging in age from 34 to 41 years and with Model for End-Stage Liver Disease scores ranging from 24 to 29. Underwent orthotopic transplantation using a liver from a deceased donor by the piggyback method. Immediately before beginning the recipient hepatectomy in a patient with FAP, a biopsy was obtained for analysis of mitochondrial function (FAP group). The control group consisted of 15 patients undergoing hepatic surgery to treat small tumors of the liver. Mitochondrial respiration was determined on the basis of oxygen consumption by energized mitochondria using a polarographic method. The membrane potential of the mitochondria was determined spectrofluorometrically. Data were analyzed statistically by the Mann-Whitney test, with the level of significance set at 5%. State 3 and 4 values, respiratory control ratio, and membrane potential were 47 +/- 8 versus 28 +/- 10 natoms O/min/mg protein (P < .05); 14 +/- 3 vs 17 +/- 7 nat.O/min/mg.prot.mit. (P > .05); 3.6 +/- .5 vs 1.7 +/- 0.7 (P < .05); and 135 +/- 5.2 vs 135 +/- 6 mV (P > .05) for control versus FAP patients, respectively, demonstrating a decreased energy status of the liver in FAP.

Effects of ischemic liver preconditioning on hepatic ischemia/reperfusion injury in the rat

To minimize bleeding during major liver resections or liver transplantation, surgical measures have been adopted that induce ischemia-reperfusion injury (I/R) which may significantly contribute to morbidity and mortality of partial liver resections. Several methods have sought to minimize I/R hepatic lesions. The present project assessed the protective role of ischemic preconditioning (IPC) in rat livers. The IPC was accomplished by clamping the hepatic pedicle for 5 minutes, followed by a 5-minute reperfusion (R) period before a 2-hour ischemia. Thereafter, reperfusions of 1, 3, and 24 hours were compared among IPC and control groups without IPC. Liver biopsy and blood samples were measured for mitochondrial respiratory control ratio (RCR), serum aspartate aminotransferase (AST), and alanine aminotransferase (ALT). IPC protected liver mitochondrial function. Serum aminotransferase levels were significantly lower among animals undergoing IPC compared with groups without IPC. Thus, we verified the effects of IPC for hepatocellular protection against I/R lesions.

Therapeutic Effect of Hyperbaric Oxygen in Hepatic Artery Thrombosis and Functional Cholestasis After Orthotopic Liver Transplantation

Among the postoperative complications, hepatic artery thrombosis can occur in up to 10% of adult orthotopic liver transplants and intervention is indicated when this occurs within 30 days by retransplantation. Primary graft dysfunction, which can occur in up to 30% of the cases and is another potential complication, although reversible, has a relatively high mortality rate. Hyperbaric therapy, an efficient mode of tissue oxygenation, is being used in an increasing number of clinical situations. We report here two cases where hyperbaric oxygen therapy greatly benefited patients with complications after orthotopic liver transplantation: one with hepatic artery thrombosis and the other with primary graft dysfunction. Both patients showed rapid clinical recovery with gradual reduction of liver and canalicular enzymes soon after commencing hyperbaric oxygen therapy.

ASPECTO FUNCIONAL DO REMANESCENTE HEPÁTICO EM CONDIÇÕES DE ISQUEMIA E REPERFUSÃO APÓS HEPATECTOMIA PARCIAL

O efeito da hipotermia, precondicionamento isquêmico e drogas protetoras das lesões de isquemia e reperfusão têm sido amplamente estudado. O objetivo do presente estudo é avaliar os efeitos da deferoxamina na isquemia e reperfusão sobre o fígado remanescente após ressecção hepática parcial a 70%, avaliando-se a função mitocondrial hepática. Estudou-se 34 ratos divididos em grupos: Grupo HP (n = 8) - submetidos a hepatectomia parcial (HP) a 70%; Grupo HPD (n = 4) - submetidos a administração 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, porém recebendo previamente deferoxamina; Grupo C (n = 8) - controle, submetido a operação simulada para HP a 70%. A análise estatística entre os diversos grupos foi feita pelos testes de Kruskal - Wallis e de Mann - Whitney, com nível de significância de 5%. Dessa maneira, o estado III foi semelhante em todos os procedimentos; o estado IV: C<HPI, C<HPID (p<0,05); a RCR: HP<C, HPD<C, HPI<C e HPID < C (p < 0,05); o PM: HPD foi maior que os demais grupos (p<0,05). Nos animais hepatectomizados a isquemia i nduziu aumento do estado IV, com e sem deferoxamina Por outro lado a deferoxamina induziu aumento do potencial de membrana nos animais hepatectomizados (HPD) em relação aos hepatectomizados com e sem isquemia. Houve diminuição da razão de controle respiratório nos animais hepatectomizados com e sem isquemia.

TRANSPLANTE DE ILHOTAS PANCREÁTICAS EM DISPOSITIVOS DE IMUNOISOLAMENTO CELULAR: RESULTADOS INICIAIS

O transplante de pâncreas e de ilhotas pancreáticas vem apresentando grande desenvolvimento nos últimos anos. O isolamento das ilhotas em cápsulas com membrana semi-permeáveis pode ser tratamento de escolha para o diabetes, pois dispensa o uso de imunossupressores. O material ideal para a confecção de uma cápsula para o isolamento celular ainda permanece um sonho. Um novo material a base de látex natural foi implantado no subcutâneo de ratos normais e diabéticos para estudar a biocompatibilidade e a neoformação vascular. A análise após 21 dias de implante mostrou intensa formação capilar na interface membrana-tecido e pouco tecido fibrótico. Estes achados iniciais mostram que o material pode ter algum potencial para a confecção de dispositivos de isolamento celular.

DUODENOPLASTIA ASSOCIADA À VAGOTOMIA GÁSTRICA PROXIMAL NO TRATAMENTO DAS ÚLCERAS DUODENAIS ESTENOSANTES

A vagotomia gástrica proximal firmou-se como o procedimento de escolha no tratamento cirúrgico eletivo das úlceras duodenais crônicas, por ser a operação mais segura quanto à morbidade e mortalidade. Sua aplicação tem sido estendida às complicações da úlcera duodenal, mediante operação complementar que visa solucionar a complicação. Com o objetivo de avaliar a vagotomia gástrica proximal no tratamento das úlceras duodenais estenosantes os resultados clínicos de uma série consecutiva de 80 pacientes submetidos à vagotomia gástrica proximal e duodenoplastia (VGP + Dp) foram comparativos aos de uma série de 106 pacientes submetidos à vagotomia gástrica seletiva e antrectomia (VGS + A); os pacientes foram avaliados 2 a 16 anos após a cirurgia. As séries foram homogêneas quanto ao sexo e à idade. Cinco diferentes tipos de duodenoplastia foram realizados, de acordo com as características anatômicas do duodeno estenosado No grupo da VGS + A a reconstrução do trânsito alimentar foi gastroduodenal em 46 pacientes e gastrojejunal nos 60 pacientes restantes. O índice de mortalidade operatória foi de 1,2% com VGP + Dp e de 1,9% com VGS + A. Controle endoscópico pós-operatório demonstrou patência da luz duodenal e piloro conservado nos pacientes submetidos à duodenoplastia. A recorrência ulcerosa ocorreu em 5% após VGP + Dp e em 1,9% após VGS + A. Conclui-se que: 1. a duodenoplastia resolve a estenose duodenal sem dano do esfíncter pilórico, mantendo as vantagens da vagotomia gástrica proximal sem operação complementar de drenagem do estômago. 2 Na avaliação clínica global os melhores resultados foram obtidos com a vagotomia gástrica proximal. 3. A vagotomia gástrica proximal associada à duodenoplastia é uma boa opção de tratamento da úlcera duodenal estenosante.