Fluorescence spectroscopy for clinical transplantation liver grafts monitoring: possibilities offered by 408 nm excitation

Purpose: Fluorescence spectroscopy techniques have been investigated aiming to reduce the invasiveness of methods for investigation of tissue. In transplantation procedures, it may offer the possibility of a complementary technique for the monitoring of liver grafts' conditions prior to and during the transplantation procedure stages involving cold perfusion. The objective of this study was to evaluate fluorescence spectroscopy under violet light excitation (408 nm) for the monitoring of clinical hypothermic liver transplantation procedures. Methods: Organ grafts were monitored from before the removal of the donor's body to 1 h after the implant into the receptor's body. Fluorescence spectroscopy was assessed over five stages within these transplant stages. Results: The study provided evidence of a correlation between fluorescence information collected during liver grafts transplantation and the survival of patients. Conclusions: Fluorescence spectroscopy can become a tool to monitor transplantation grafts, providing objective information for the final decision of surgeons to use organs.

Effect of irradiation with different laser wavelengths on oxidative stress of non-hepatectomized rats

PURPOSE: To assess the effect of two laser wavelengths, either separate or combined, on intact rat livers. METHOD: Nineteen male Wistar rats (200-300 g) were submitted to laser irradiation at 5 different sites on the liver surface.Wavelengths 660 and 780 nm were used, with a dose of irradiation of 60 J/cm2/site.The animals were divided into the groups:control (C) and animals irradiated with 660 nm laser (L1), with 780 nm laser (L2) or withboth wavelengths (L3).Mitochondrial function, mitochondrial swelling, and hepatocellular malondialdehyde (MDA) levels were determined.Data were analyzed by the Mann-Whitney test, with the level of significance set at 5%. RESULTS: There was a reduction of ADP-activated respiration (state 3) in group L1 compared to group C (p=0.0016), whereas the values of group L2 were similar to control.Group L3 also showed a reduction of state 3 (p=0.0159).There was a reduction of RCR in group L1 compared to control (p=0.0001) and to group L2 (p=0.0040).Mitochondrial swelling only differed between group L3 and control (p=0.0286).There was a increase in MDA levels in group L3 compared to control (p=0.0476) and to group L2 (p=0.0286) and in group L1 compared to group L2 (p=0.0132). CONCLUSION: Although laser irradiation reduced mitochondrial function,it did not interfere with the hepatocellular energy status.(AU)

Effect of laser on the remnant liver after the first 24 hours following 70% hepatectomy in rats / Efeito do laser no fígado remanescente nas primeiras 24 horas após hepatectomia a 70% em ratos

PURPOSE: To evaluate the mitochondrial function of the remnant liver (RL) in the early phase of liver regeneration in rats after 70% partial hepatectomy (PH). METHODS: Sixty male Wistar rats (200-250g) submitted to 70% PH were divided into five groups according to the time of euthanasia and application or not of laser light: C = Control, time zero; 2 minutes, 4, 6 and 24 hours after PH. The dose of laser radiation was 22.5 J/cm2, wavelength of 660 nm (visible/red), in the remnant liver. We studied the respiration activated by ADP (state 3), basal mitochondrial respiration (state 4), respiratory control ratio (RCR) and mitochondrial membrane potential (MMP). RESULTS: The mitochondrial function of RL changed at 4 and 6 hours after PH, with a significant increase in state 3 and a concomitant increase in state 4 and with maintenance of RCR. MMP differed significantly between the groups biostimulated with laser radiation and the control group 4 hours after HP, with a substantial reduction in the non-laser groups. CONCLUSION: The laser light at the dose used in this study did not induce additional damage to the RL and seems to have delayed the hepatocellular metabolic overload of the remnant liver.(AU)

OBJETIVO: Avaliar a função mitocondrial do fígado remanescente (FR) na fase precoce da regeneração hepática em ratos após hepatectomia parcial (HP) a 70%. MÉTODOS: Sessenta ratos machos Wistar (200 - 250g) submetidos à HP a 70%, foram distribuídos em cinco grupos de acordo com o tempo de eutanásia e com aplicação ou não de luz laser: C= Controle,tempo zero; 2 minutos, 4, 6 e 24 horas após HP. O laser foi utilizado na dose 22.5 J/cm2, 660 nm, no FR.Estudou-se o estado 3 (respiração ativada por ADP), estado 4 (respiração mitocondrial basal), razão de controle respiratório,estado 3/estado 4 (RCR) e o potencial de membrana mitocondrial(PMM). RESULTADOS: A função mitocondrial do FR alterou-se no período de 4 e 6 horas após a HP com aumento significativo do estado 3 e aumento concomitante do estado 4, com manutenção da RCR. O PMM apresentou diferença significativa entre os grupos bioestimulados com laser e o controle a partir de 4 horas pós HP, com queda importante do grupo sem laser e tendência a equiparação dos valores após 24 horas. CONCLUSÃO: A luz laser, na dose utilizada no presente estudo, não induziu lesão adicional ao FR e parece ter retardado a sobrecarga hepatocelular do fígado remanescente.(AU)

New photonic technologies for the treatment and diagnosis of hepatic diseases: an overview of the experimental work performed in collaboration, between Physics Institute of São Carlos and Ribeirão Preto Faculty of Medicine of the University of São Paulo / Novas tecnologias fotônicas no tratamento e diagnóstico de doenças hepáticas: uma revisão dos trabalhos experimentais realizados em colaboração, entre o Instituto de Física de São Carlos e a Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo

Recent advances in optical techniques have created a great range of possibilities for diagnosis and therapeutics in liver related diseases. With the uses of efficient light sources like lasers and LEDs (Light Emitting Diodes) it is possible to employ the light-tissue interaction to promote hepatic tissue regeneration after partial hepatectomy, to detect hepatocarcinoma and steatosis by utilizing optical fluorescence, to evaluate the metabolism of the liver during hepatic transplantation as well as to treat liver tumors. We present here an overview of the technique presently in development at the Ribeirâo Preto Faculty of Medicine - USP in cooperation with the Physics Institute of São Carlos -USP. The results obtained so far have been the subject of a list of publications and are here presented as an overview. A new perspective for modern application of optical techniques in different medical practices related to the liver is presented.(AU)

Recentes avanços em técnicas ópticas têm propiciado vasto campo de possibilidades tanto para o diagnóstico quanto para a terapêutica de doenças hepáticas.Com o uso de eficientes fontes de luz como o laser e Light emitting diodes (LED) é possível utilizar a interação luz-tecido para promover a regeneração hepática após hepatectomias parciais,detectar hepatocarcinoma, esteatose e outras alterações do fígado pelo uso da fluorescência óptica,para avaliar o metabolismo hepático durante o transplante de fígado e na abordagem diagnóstica e terapêutica de alterações hepatocelulares. Os autores apresentam uma ampla revisão de técnicas atualmente em desenvolvimento na Divisão de Gastroenterologia Cirúrgica da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo num trabalho cooperativo com o Instituto de Física de São Carlos da USP. Os resultados obtidos até agora têm sido motivo de lista de publicações que são aqui apresentados em forma de revisão. Uma nova perspectiva de moderna aplicação de técnicas ópticas em várias situações clínico-cirúrgicas relacionadas com o fígado é apresentada e amplamente discutida.(AU)

The effect of laser on remanescent liver tissue after 90 percent hepatectomy in rats / Efeito do laser no tecido hepático após hepatectomia a 90 por cento em ratos

PURPOSE: To evaluate the effect of laser beam on remanescent liver after partial hepatectomy 90 percent. METHODS: Wistar rats, (N= 42), were divided into six groups with seven specimens each. The partial hepatectomy (HP) was performed in all animals through exeresis of approximately 90 percent of the liver parenchyma. The animals from groups HP and Laser application, HPL24, HPL48 and HPL72 undertook laser irradiation carried out through application (dose of 22.5 J/cm²) in five different sites in the remanescent liver. The rats were then sacrificed 24, 48 and 72hours after HP procedure, for the liver regeneration analysis,using the Proliferating Cell Nuclear Antigen (PCNA),and for dosage of serum aminotransferases. RESULTS: Were demonstrated an increase of the serum levels of alanine aminotransferase for the group of 24 hours and a decrease for the group of 72 hours exposed to laser. The index of marked cells had a considerable more improvement for the group of 72 hours exposed in laser compared to other groups. CONCLUSION: Laser did not cause hepatic injuries additional to the partial hepatectomy and perhaps led to a benefit by stimulating the proliferative activity.(AU)

OBJETIVO: Avaliar o efeito da luz laser em remanescentes hepáticos após hepatectomia a 90 por cento. MÉTODOS: Aplicou-se luz laser com comprimento de onda de 660 nm e potência de 30 mw, por 30 segundos, na dose de 22,5 J/cm² em cada um deles, repetidos em cinco pontos do fígado remanescente, após realizada a hepatectomia a 90 por cento. Os animais foram sacrificados para análise do fígado, contagem de hepatócitos em proliferação (Proliferating Cell Nuclear Antigen -PCNA), e coleta de sangue para dosagem serica das aminotransferases, após 24, 48 e 72 horas. RESULTADO: O índice de células marcadas teve significativo aumento no grupo de 72 horas irradiados com laser. CONCLUSÃO: A análise dos resultados demonstrou que o laser não causou lesões hepáticas adicionais à hepatectomia parcial e estimulou a atividade proliferativa hepatocelular.(AU)