Study of laser fluorescence spectroscopy in livers of rats with hypothermic ischemia

Purpose: After partial hepatectomy (PH), the remaining liver (RL) undergoes regenerative response proportional to the host. Limited literature exists on hepatic viability after tissue injury during hypothermic preservation. Spectroscopy measures cellular fluorescence and is explored for tissue characterization and parameter investigation. This study aimed to assess fluorescence analysis (spectroscopy) in evaluating liver viability and its relationship with hepatic tissue regeneration 24 hours after PH. Additionally, we analyzed liver regeneration in RL after 70% partial hepatectomy under hypothermic conditions with laser irradiation. Methods: Fifty-six Wistar rats were divided into four groups: total non-perfused liver (control), total perfused liver, partial hepatectomy "in situ", and partial hepatectomy "ex situ". Tissue analysis was performed at 0 and 24 hours using spectroscopy with laser devices emitting at 532 (green) and 405 nm (violet). Results: Spectroscopy identified tissue viability based on consistent results with Ki67 staining. The fluorescence spectra and Ki67 analysis displayed similar patterns, linking proliferative activity and absorption intensity. Conclusions: Fluorescence spectroscopy proves to be promising for real-time analysis of cellular activity and viability. Metabolic activity was observed in groups of live animals and hypothermically preserved samples, indicating cellular function even under blood deprivation and hypothermic conditions.

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.

Photodynamic therapy of extrahepatic cholangiocarcinoma using digital cholangioscopy / Terapia fotodinâmica em colangiocarcinoma extra-hepático utilizando colangioscopia digital

ABSTRACT Background: Cholangiocarcinoma is an aggressive neoplasm that usually requires palliative biliary drainage. Photodynamic therapy (PDT) has been described as a successful adjunct treatment to malignant biliary obstruction. Aim: To describe the use of digital cholangioscope to help provide laser light during biliary PDT session using locally developed light source. Method: Patient receives intravenous photosensitizer 24 h before the procedure. It starts with a regular duodenoscopy. After identification of the major papilla and retrograde cannulation, the digital cholangioscope is introduced into the common bile duct. Then, the cholangioscopic examination helps to identify the neoplastic stricture. Under direct visualization lighting catheter is advanced through the cholangioscope. Repositioning is recommended every centimeter to cover all strictured area. At the end of the procedure, a final cholangioscopy assesses the bile duct for the immediate result and adverse events. Result: This procedure was applied in one 82-year-old male due to obstructive jaundice in the last two months. EUS and ERCP revealed a severe dilation of the common bile duct associated with choledocholithiasis. Besides, was revealed dilation of hepatic duct up to a well-circumscribed hypoechoic solid mass measuring 1.8x2 cm compressing the common hepatic duct. The mass was deemed unresectable and the patient was referred for palliative treatment with PDT. He remained asymptomatic for three months. He perished due to complications 15 months after the PDT session. Conclusion: Digital cholangioscopy-guided biliary PDT is feasible and seems safe and effective as an adjunct modality in the palliation of extrahepatic cholangiocarcinoma.

RESUMO Racional: Colangiocarcinoma é neoplasia agressiva que geralmente exige drenagem biliar paliativa. A terapia fotodinâmica (TFD) tem sido descrita como tratamento adjunto bem-sucedido para tratar obstrução biliar maligna. Objetivo: Descrever o emprego do colangioscópio digital para ajudar a fornecer luz de laser durante sessão de TFD biliar usando fonte de luz desenvolvida localmente. Método: Paciente recebe fotossensibilizador intravenoso 24 h antes do procedimento que começa com duodenoscopia regular. Após a identificação da papila principal e da canulação retrógrada, o colangioscópio digital é introduzido no ducto biliar comum. Em seguida, o exame colangioscópico ajuda a identificar a estenose neoplásica. Sob visualização direta, o cateter de iluminação avança através do colangioscópio. Reposicionamento é feito a cada centímetro. Ao final colangioscopia avalia o ducto biliar quanto ao resultado imediato e a eventos adversos. Resultado: Este procedimento foi aplicado em um homem de 82 anos devido à icterícia obstrutiva nos últimos dois meses. EUS e CPRE revelaram dilatação grave do ducto biliar comum associada à coledocolitíase. Além disso, havia dilatação do ducto hepático até massa sólida hipoecóica bem circunscrita, medindo 1,8x2 cm, comprimindo o ducto hepático comum. Ela foi considerada irressecável e paciente encaminhado para tratamento paliativo com TFD que permaneceu assintomático por três meses. Morreu devido a complicações 15 meses após a sessão de TFD. Conclusão: A TFD biliar guiada por colangioscopia digital é viável e parece segura e eficaz como modalidade auxiliar na paliação de colangiocarcinoma extra-hepático.

Prophylactic application of laser light restores L-FABP expression in the livers of rats submitted to partial ischemia

OBJECTIVES: The objective of the present study was to evaluate the protective effect of pre-conditioning treatment with laser light on hepatic injury in rats submitted to partial ischemia using mitochondrial function and liver fatty acid binding protein as markers. METHODS: Rats were divided into four groups (n=5): 1) Control, 2) Control + Laser, 3) Partial Ischemia and 4) Partial Ischemia + Laser. Ischemia was induced by clamping the hepatic pedicle of the left and middle lobes of the liver for 60 minutes. Laser light at 660 nm was applied to the liver immediately prior to the induction of ischemia at 22.5 J/cm2, with 30 seconds of illumination at five individual points. The animals were sacrificed after 30 minutes of reperfusion. Blood and liver tissues were collected for analysis of mitochondrial function, determination of malondialdehyde and analysis of fatty acid binding protein expression by Western blot. RESULTS: Mitochondrial function decreased in the Partial Ischemia group, especially during adenosine diphosphate-activated respiration (state 3), and the expression of fatty acid binding protein was also reduced. The application of laser light prevented bioenergetic changes and restored the expression of fatty acid binding protein. CONCLUSION: Prophylactic application of laser light to the livers of rats submitted to partial ischemia was found to have a protective effect in the liver, with normalization of both mitochondrial function and fatty acid binding protein tissue expression.

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.