Research progress in lineage tracing to explore hepatic parenchymal cell regeneration and repair mechanisms / 中华肝脏病杂志

Hepatic parenchymal cells are a type of liver cells that performs important functions such as metabolism and detoxification. The contribution of hepatic parenchymal cells, bile duct cells, and hepatic stem/progenitor cells to new hepatic parenchymal cells in the process of liver injury repair has become a controversial issue due to their strong proliferation ability. Lineage tracing technology, which has emerged in the past decade as a new method for exploring the origin of cells, can trace specific type of cells and their daughter cells by labeling cells that express the specific gene and their progeny. The article reviews the current literature on the origin and contribution of hepatic parenchymal cells by this technique. About 98% of new hepatic parenchymal cells originate from the existing hepatic parenchymal cells during liver homeostasis and after acute injury. However, under conditions of severe liver injury, such as inhibition of hepatic parenchymal cell proliferation, bile duct cells (mainly liver stem/progenitor cells) become the predominant source of hepatic parenchymal cells, contributing a steady increased hepatocyte regeneration with the extension of time.

Assessment of remnant liver function and volume after selective ligation of portal vein and hepatic artery in a rat model

Abstract Purpose: To evaluate liver regeneration after selective ligation of portal vein and hepatic artery by 3D Computed Tomography in an experimental model. Methods: Sixteen Wistar rats were randomized into four equal groups: Group I- control (sham), Group II- isolated selective ligation of the hepatic artery, Group III- isolated selective ligation of the portal vein and Group IV- combined ligation of portal vein and hepatic artery. Before procedure and five days after a 3D CT Scan was performed to analyze the hypertrophy, weight and function of the remnant liver. Results: The largest regeneration rate and increase of weight in the hypertrophied lobe was detected in group IV, the first with an average of 3.99 (p=0.006) and the last varying from 6.10g to 9.64g (p=0.01). However, total liver weight and the R1 ratio (Hypertrophied Lobe Weight/Total Liver Weight) was higher in group III (P<0.001) when compared with groups I, II and IV and showed no difference between them. The immunohistochemical examination with PCNA also found higher percentages with statistical significance differences in rats of groups III and IV. It was possible to confirm a strong correlation between hypertrophied lobe weight and its imaging volumetric study. Liver function tests only showed a significant difference in serum gamma-glutamyltransferase and phosphorous. Conclusion: There is a largest liver regeneration after combined ligation of portal vein and hepatic artery and this evidence may improve the knowledge of surgical treatment of liver injuries, with a translational impact in anima nobile.

Multiple factors affect the regeneration of liver

SUMMARY OBJECTIVE To study factors affecting the liver regeneration after hepatectomy METHODS With 3D reconstitution technology, liver regeneration ability of 117 patients was analysed, and relative factors were studied. RESULTS There was no statistically difference between the volume of simulated liver resection and the actual liver resection. All livers had different degrees of regeneration after surgery. Age, gender and blood indicators had no impact on liver regeneration, while surgery time, intraoperative blood loss, blood flow blocking time and different ways of liver resection had a significant impact on liver regeneration; In addition, the patients' own pathological status, including, hepatitis and liver fibrosis all had a significant impact on liver regeneration. CONCLUSION 3D reconstitution model is a good model to calculate liver volume. Age, gender, blood indicators and biochemistry indicators have no impact on liver regeneration, but surgery indicators and patients' own pathological status have influence on liver regeneration.

RESUMO OBJETIVO Estudar os fatores que afetam a regeneração hepática após hepatectomia. MÉTODOS A capacidade de regeneração hepática de 117 pacientes foi analisada com a tecnologia de reconstituição 3D e foram estudados os fatores relacionados. RESULTADOS Não houve diferença estatística significante entre o volume de ressecção hepática simulada e a ressecção atual. Todos os fígados apresentaram diferentes graus de regeneração após cirurgia. Idade, gênero e indicadores sanguíneos não tiveram impacto na regeneração hepática, enquanto que tempo de cirurgia, perda sanguínea intraoperatória, tempo de bloqueio do fluxo sanguíneo e diferentes formas de ressecção mostraram impacto significante na regeneração do órgão. Além disso, condições patológicas dos pacientes, incluindo hepatite e fibrose hepática, tiveram impacto significante na regeneração hepática. CONCLUSÃO O modelo de reconstituição 3D é um bom modelo para calcular o volume do fígado. Idade, gênero, indicadores sanguíneos e bioquímicos não tiveram impacto na regeneração hepática, mas indicadores operatórios e condição patológica dos pacientes mostraram influência na regeneração do órgão.

Functional and cellular evaluation of the liver after low-power laser stimulation during surgery / Avaliação celular e funcional do fígado estimulada por laser de baixa potência no transoperatório

ABSTRACT Background: Partial hepatectomy is a surgical intervention of the liver that can trigger its regenerative process, where the residual lobes deflagrate a compensatory hyperplasia, causing its restoration almost to the original volume. Nevertheless, depending on the extent of liver damage its regeneration might be impaired. The low-power laser has been studied with beneficial results. Aim: To investigate the possible functional and mutagenic damage arising from the use of low-power laser used in liver regeneration after partial hepatectomy. Methods: Fifteen male adult Wistar rats were hepatectomizated in 70% and laser irradiated or not with dose of 70 J/cm2, 650 nm, 100 mW, directly on the remaining liver, during the perioperative period. These animals were divided into four groups: G1 (control, 7 days); G2 (laser, 7 days); G3 (control, 14 days); G4 (laser, 14 days). Were analyzed the liver weight; number of hepatocytes; deposition of collagen fibers; liver function tests: serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, bilirubin and micronucleus test in peripheral blood erythrocyte. Results: The liver weight was greater in G3 and G4 (p=0.001 and p=0.002) compared to other groups. The deposition of collagen fibers in G1 was statistically higher than the other groups (p=0.01). In tests of liver function and micronucleus test was not found significant differences between the studied groups. Conclusion: Low-power laser stimulation did not cause loss of liver function or mutagenic damage.

RESUMO Racional: A hepatectomia parcial é intervenção cirúrgica que pode desencadear processo regenerativo, onde os lobos residuais deflagram resposta de hiperplasia compensatória, ocasionando restauração próxima ao seu volume original. Contudo, dependendo da extensão das lesões hepáticas a regeneração pode ser prejudicada. O laser de baixa potência tem sido pesquisado com resultados benéficos no processo de regeneração hepática. Objetivo: Investigar os possíveis danos funcionais e mutagênicos decorrentes da utilização do laser de baixa potência utilizado na regeneração hepática após hepatectomia parcial. Métodos: Quinze ratos adultos Wistar foram hepatectomizados a 70%, irradiados ou não com laser, dose de 70 J/cm2, 650 nm,100 mW, de forma direta sobre o fígado remanescente, durante o período transoperatório. Os animais foram distribuídos em quatro grupos: G1 (controle, 7 dias); G2 (laser, 7 dias); G3 (controle 14 dias); G4 (laser,14 dias). Foram analisados o peso do fígado; número de hepatócitos; deposição de fibras colágenas; teste de função hepática: alanina aminotransferase, aspartato aminotransferase, fosfatase alcalina, gama glutamiltransferase, bilirrubinas e teste de micronúcleo em eritrócitos. Resultados: O peso do fígado apresentou-se aumentado nos grupos G3 e G4 (p=0,001 e p=0,002) comparados aos demais grupos. A deposição das fibras colágenas no G1 foi estatisticamente maior em relação aos demais grupos (p=0,01). Nos testes de função hepática e teste de micronúcleo não foram encontradas diferenças significativas entre os grupos. Conclusão: O laser de baixa potência não ocasionou perda de função hepática ou dano mutagênico.

The Role of Mesothelial Cells in Liver Development, Injury, and Regeneration

Mesothelial cells (MCs) cover the surface of visceral organs and the parietal walls of cavities, and they synthesize lubricating fluids to create a slippery surface that facilitates movement between organs without friction. Recent studies have indicated that MCs play active roles in liver development, fibrosis, and regeneration. During liver development, the mesoderm produces MCs that form a single epithelial layer of the mesothelium. MCs exhibit an intermediate phenotype between epithelial cells and mesenchymal cells. Lineage tracing studies have indicated that during liver development, MCs act as mesenchymal progenitor cells that produce hepatic stellate cells, fibroblasts around blood vessels, and smooth muscle cells. Upon liver injury, MCs migrate inward from the liver surface and produce hepatic stellate cells or myofibroblast depending on the etiology, suggesting that MCs are the source of myofibroblasts in capsular fibrosis. Similar to the activation of hepatic stellate cells, transforming growth factor β induces the conversion of MCs into myofibroblasts. Further elucidation of the biological and molecular changes involved in MC activation and fibrogenesis will contribute to the development of novel approaches for the prevention and therapy of liver fibrosis.

Which is the best route of administration for cell therapy in experimental model of small-for size syndrome in rats?

PURPOSE: To evaluate which is the best route of administration for cell therapy in experimental rat model of small-for size syndrome. METHODS: A total of 40 rats underwent partial hepatectomy (70%) that induces the small-for-size syndrome and were divided into four groups of route administration: intravenous, intraperitoneal, enteral and tracheal. The small-for-size syndrome model was designed with extended partial hepatectomy (70%). The animals were divided into four groups of routes administration: intravenous (n=10) - intravenously through the dorsal vein of the penis; intraperitoneal (n=10) - intraperitoneally in the abdominal cavity; enteral (n=10) - oroenteral with the placement of a number 4 urethral probe and maintained at third duodenal portion; tracheal (n=10) - after tracheal intubation. We track the animals and monitor them for 21 days; during this follow-up we evaluated the result of cell therapy application tracking animals using ultrasound, radiography and PET-scan. Statistical analysis was performed using GraphPad Prism Software(r). Differences were considered significant with the p<0.05. Data are presented as the median and variation for continuous variables. Comparisons between groups were made using analysis of the imaging test by the researchers. RESULTS: All four groups underwent partial hepatectomy of 70% liver tissue targeting the same weight of resected liver. Initially the PET-scan tests showed similarity in administered cells by different routes. However, in few days the route of intravenous administration showed to be the most appropriated to lead cells to the liver followed by enteral. The tracheal and peritoneal routes were not as much successful for this goal. CONCLUSION: The intravenous route is the best one to cell therapy in experimental rat model of small-for size-syndrome. .

Densidad superficial nuclear de hepatocitos de hígados sometidos a un factor estimulante humoral en ratones / Superficial nuclear density of hepatocytes of livers subjected to a humoral stimulating factor in mice

FUNDAMENTO: la regeneración hepática es la respuesta fundamental del hígado frente a los diversos estímulos internos y externos. Es multifactorial inducida, que origina cambios secuenciales en la expresión génica, la estructura y organización de las células hepáticas. OBJETIVOS: analizar el comportamiento de la densidad superficial de los núcleos de los hepatocitos según la posición que ocupan en las zonas del lóbulo hepático medio de ratones sometidos a citosol regenerativo. Método: se estudió la densidad superficial de los núcleos de hepatocitos con el uso de la morfometría en 14 lóbulos medios de hígados de ratones, que fueron sometidos a dosis de citosol de hígado regenerativo al inicio del experimento. Las muestras fueron tomadas cada 12 horas durante ocho días. El corte se dividió en zonas proximal, medial y distal al hilio donde se realizaron las determinaciones. RESULTADOS: los valores promedios y su desviación estándar en la zonas fueron: proximal 701,23 ± 135,83 (μm2.103), medial 707,48 ± 46,87 (μm2.103) y distal 682,48 ± 125,21 (μm2.103). Al comparar los resultados mediante el análisis de varianza se aprecia que no existen diferencias en el comportamiento de los promedios en las tres zonas. Al comparar la fase inicial con la fase final del experimento se aprecia diferencias significativas (p ≤ 0,05) en las mismas zonas, con un predominio de la zona proximal y distal. CONCLUSIONES: en las tres zonas del lóbulo el comportamiento de la densidad superficial de núcleos de hepatocitos ocurre de manera similar, con un sentido al incremento al final del experimento, lo que se corroboró con la aplicación de la prueba de la t de Student. Los incrementos más significativos ocurrieron en la zona proximal y distal, aunque en todas las zonas existen diferencias significativas entre los valores obtenidos en la primera mitad de tiempo del experimento respecto a la parte final.

BACKGROUND: hepatic regeneration is the basic answer of the liver to various internal and external stimuli. It is multifactorial and induced and originates sequential changes in the gene expression, the structure and organization of hepatic cells. OBJECTIVE: to analyze the behaviour of the superficial density of the nuclei of the hepatocytes according to the position they have in the areas of the middle hepatic lobes of mice subjected to regenerative cytosol. METHOD: the superficial density of the nuclei of the hepatocytes was studied with the use of morphometry in 14 middle hepatic lobes of mice subjected to a dose of regenerative liver cytosol at the beginning of the experiment. The samples were taken every 12 hours during eight days. The cut was divided into proximal, medial and distal areas to the hilum, where the determinations were made. Results: the average values and their standard deviations in the areas were: proximal 701,23 ± 135,83 (μm2.103), medial 707,48 ± 46,87 (μm2.103) y distal 682,48 ± 125,21 (μm2.103). When comparing the results through the analysis of variance, it could be seen that there are not differences among the averages in the three areas. When comparing the initial stage with the final stage of the experiment major differences (p ≤ 0,05) could be seen in the same areas, predominating the proximal and distal area. CONCLUSIONS: in the three areas of the lobe the behaviour of the superficial density of the nuclei of the hepatocytes is similar, with a tendency to increase at the end of the experiment. This could be corroborated with the application of the Student’s t- test. In spite of the fact that there were major differences between the values obtained in the first part and the final part of the experiment in all the areas, the most significant increases occurred in the proximal and distal areas.

Evaluation of liver regeneration with use of diet supplemented with l-arginine

PURPOSE: To compare controlled liver regeneration in rats submitted to 60% hepatic resection having L-arginine supplemented diet, based on weight changes of the regenerated liver, laboratory parameters of liver function and pathological findings. METHODS: Thirty-six rats were divided into two groups, control and L- arginine. The first received standard chow and saline solution by gavage. The second had supplementation with L- arginine. Animals were killed on postoperative period at 24h, 72h and seven days. For analysis of liver regeneration was used Kwon formula for weight, laboratory tests and mitosis. RESULTS: Weight, showed no benefit with L- arginine supplementation; however, intergroup comparison in the first 24h observed positive effect on supplementation (p=0.008). Alkaline phosphatase was increased in arginine group (p<0.04). The number of mitoses showed no difference between the two groups; however, in the first 24 hours, the supplemented group had higher number of mitoses within the groups (p=0.03). CONCLUSION: Supplementation with L-arginine did not show benefits in liver regeneration; however, supplemented group in the first 24 hours showed benefits over 72 hours and seven days of the evaluation by weight gain and number of mitosis. .

Glutamine and ornithine alpha-ketoglutarate supplementation on malate dehydrogenases expression in hepatectomized rats

PURPOSE: To evaluate the relative gene expression (RGE) of cytosolic (MDH1) and mitochondrial (MDH2) malate dehydrogenases enzymes in partially hepatectomized rats after glutamine (GLN) or ornithine alpha-ketoglutarate (OKG) suplementation. METHODS: One-hundred and eight male Wistar rats were randomly distributed into six groups (n=18): CCaL, GLNL and OKGL and fed calcium caseinate (CCa), GLN and OKG, 0.5g/Kg by gavage, 30 minutes before laparotomy. CCaH, GLNH and OKGH groups were likewise fed 30 minutes before 70% partial hepatectomy. Blood and liver samples were collected three, seven and 14 days after laparotomy/hepatectomy for quantification of MDH1/MDH2 enzymes using the real-time polymerase chain reaction (PCR) methodology. Relative enzymes expression was calculated by the 2-ΔΔC T method using the threshold cycle (CT) value for normalization. RESULTS: MDH1/MDH2 RGE was not different in hepatectomized rats treated with OKG compared to rats treated with CCa. However, MDH1/MDH2 RGE was greater on days 3 (321:1/26.48:1) and 7 (2.12:1/2.48:1) while MDH2 RGE was greater on day 14 (7.79:1) in hepatectomized rats treated with GLN compared to control animals. CONCLUSION: Glutamine has beneficial effects in liver regeneration in rats by promoting an up-regulation of the MDH1 and MDH2 relative gene expression. .

The ileum positively regulates hepatic regeneration in rats

To test the hypothesis that liver regeneration after partial hepatectomy can be influenced by the ileum. METHODS: Eighteen Wistar rats were distributed into groups of six animals: 1 - ileum resection+ hepatectomy 2/3; 2 - hepatectomy 2/3, and 3 - sham. Anesthesia with ketamine and xylazine i.p., aseptic technique, analgesia with meperidine (10mg/kg s.c.). On day 6, serum ALT, AST, alkaline phosphatase (AP) and albumin were measured. Liver regeneration and hepatocyte mitosis were quantified. Statistical analysis with ANOVA and Tukey tests, with significance p<0.05. RESULTS: In group hepatectomy+ileal resection, ALT, AST and AP were 180.6±24.9, 58.6±3.1 and 254.6±46.6 respectively. They were significantly higher than in the hepatectomy group, whose values were 126.0±16.5, 44.1±3.9 and 163.5±8.6, respectively (p<0.001). Albumin levels were not significantly different among groups. Liver regeneration in hepatectomy group (94.17%) was statistically higher (p<0.001) than in ileal resection+hepatectomy group (55.96%). In the latter group the mitosis of hepatocytes were significantly less frequent than in the hepatectomy group. CONCLUSION: The data confirm that the ileum positively influence on liver regeneration in rats undergoing hepatectomy.

Proteomic analysis of the regenerating liver following 2/3 partial hepatectomy in rats

BACKGROUND: Liver regeneration (LR) after 2/3 partial hepatectomy (PH) is one of the most studied models of cell, organ, and tissue regeneration. Although the transcriptional profile analysis of regenerating liver has been carried out by many reserachers, the dynamic protein expression profile during LR has been rarely reported up to date. Therefore, this study aims to detect the global proteomic profile of the regenerating rat liver following 2/3 hepatectomy, thereby gaining some insights into hepatic regeneration mechanism. RESULTS: Protein samples extracted from the sham-operated and the regenerating rat livers at 6, 12, 24, 72, 120 and 168 h after PH were separated by IEF/SDS-PAGE and then analyzed by MALDI-TOF/TOF mass spectrometry. Compared to sham-operated groups, there were totally 220 differentially expressed proteins (including 156 up-regulated, 62 down-regulated, and 2 up/down-regulated ones) identified in the regenerating rat livers, and most of them have not been previously related to liver regeneration. According to the expression pattern analysis combined with gene functional analysis, it showed that lipid and carbohydrate metabolism were enhanced at the early phase of LR and continue throughout the regeneration process. Ingenuity Pathway Analysis indicated that YWHAE protein (one of members of the 14-3-3 protein family) was located at the center of pathway networks at all the timepoints after 2/3 hepatectomy under our experimental conditions, maybe suggesting a central role of this protein in regulating liver regeneration. Additionally, we also revealed the role of Cdc42 (cell division cycle 42) in the termination of LR. CONCLUSIONS: For the first time, our proteomic analysis suggested an important role of YWHAE and pathway mediated by this protein in liver regeneration, which might be helpful in expanding our understanding of LR amd unraveling the mechanisms of LR.

Effects of bioflavonoid ternatin on liver regeneration and oxidative stress in rats

PURPOSE: To evaluate the effect of bioflavonoid ternatin (TRT) on rat liver regeneration and oxidative stress after 70% partial hepatectomy (PH). METHODS: Thirty six young male Wistar rats were randomly assigned to two groups of 18 animals each - control (G1) and experimental (G2) - and were submitted to PH under inhalatory diethylether anesthesia. G1 rats received daily intraperitoneal (ip) injections of saline (NaCl 0.9% solution) 0.1 mL/kg for 14 days; G2 animals received daily ip injections of TRT 0.1% 1.0mg/kg for 14 days. At 36h (T1), 168h (T2) and 336h (T3) post-PH timepoints, a subgroup of six rats in each group was chosen in a randomized way to complementary hepatectomy (CH) and blood samples haversting. Collected material was saved for laboratory analysis (total bilirubin (TB), D-Glucose, glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) and assessment of liver regeneration. RESULTS: TRT induced a significant decrease in liver and plasma GSH concentrations; liver regeneration process was not affected. TRT promoted a significant decrease in blood glucose levels 168h after partial hepatectomy compared with controls. TB levels remained unchanged. CONCLUSION: Intraperitoneal bioflavonoid ternatin injection in partially hepatectomized rats induces a decrease in oxidative stress and a significant hypoglycemic state, but does not promote any change in the evolution of liver regeneration.

Regeneración hepática en enfermedad de hígado graso no-alcohólica / Liver regeneration in nonalcoholic fatty liver disease

La esteatosis hepática es el acúmulo de grasa en los hepatocitos, que puede ser la consecuencia del proceso de regeneración hepática o de procesos patológicos como la enfermedad del hígado graso alcohólica y no-alcohólica. A pesar de su importancia, en ambos casos el mecanismo exacto en que la esteatosis influye en la regeneración hepática es escasamente comprendido. Estudios previos han demostrado que los pacientes que presentan hígado graso expresan una regeneración hepática dispar, posiblemente debido a la acumulación de especies reactivas de oxígeno generada por procesos inflamatorios ocasionados por activación de las células de Kupffer. En este artículo se revisan distintos factores que afectan la regeneración hepática, tratando de comprender el mecanismo involucrado en la regeneración dispar en hígados con esteatosis ocasionada por una enfermedad de hígado graso no-alcohólica.

Steatosis is the accumulation of fat in hepatocytes, which may be the result of liver regeneration or pathological processes such as alcoholic and nonalcoholic fatty liver disease. Despite its importance, in both cases the exact mechanism that prevails in fatty liver regeneration is poorly understood. Previous studies have shown that patients with fatty liver express dispar regeneration, possibly due to the accumulation of reactive oxygen species generated by inflammatory processes caused by activation of Kupffer cells. In this article we review several factors that affect liver regeneration, trying to understand the underlying mechanism of dispar regeneration in fatty liver as a consequence of nonalcoholic fatty liver disease.

Impact of hypertension in liver regeneration in rats / Repercussão da hipertensão arterial na regeneração hepática em ratos

PURPOSE: To determine the impact of hypertension in liver regeneration, in rats by examining gain in liver mass and the replication of hepatocytes and stellate cells. METHODS: Forty Wistar rats were allocated into two groups of twenty, the control and experiment group. The experiment group animals were submitted to induction of renovascular hypertension. A week later, all the animals underwent a partial hepatectomy. Measurements were taken after 24 hours and seven days, when ten animals in each group were euthanized. Thus, four subgroups were obtained. The livers were excised and sent for histopathological analysis. RESULTS: The control group had a greater gain in liver mass than the experiment group seven days after partial hepatectomy (p=0.0051). The difference in the activate stellate cell count was not statistically significant following analysis after both 24 hours and seven days (p=1.0). A higher number of dividing hepatocytes was observed in the control group seven days after partial hepatectomy (p=0.0014). CONCLUSION: In rats, hypertension had no direct influence on stellate cell replication, but led to a delay in liver mass gain and were shown to be a reduction factor on hepatocyte replication seven7 days after partial hepatectomy.

OBJETIVO: Determinar o impacto da hipertensão arterial sistêmica na regeneração hepática, em ratos, através da análise do ganho de massa hepática e da replicação dos hepatócitos e das células estreladas. MÉTODOS: Alocaram-se 40 ratos Wistar em dois grupos de 20 animais, os grupos controle e experimento. Os do grupo experimento submeteram-se a indução da hipertensão renovascular. Uma semana após, realizou-se hepatectomia parcial em todos os animais. Colheram-se os dados com 24 horas e sete dias, quando dez animais de cada grupo submeteram-se a eutanásia. Assim, obtiveram-se quatro subgrupos. Os fígados foram retirados e enviados para análise histopatológica. RESULTADOS: O grupo controle apresentou maior ganho de massa hepática do que o grupo experimento sete dias após a hepatectomia parcial (p=0,0051). A diferença na contagem das células estreladas ativadas não foi estatisticamente significante nas análises de 24 horas e de sete dias (p=1,0). Um maior número de hepatócitos em divisão foi observado no grupo controle, sete dias após a hepatectomia parcial (p=0,0014). CONCLUSÃO: Em ratos, a hipertensão não teve influência direta sobre a replicação de células estreladas, mas levou ao atraso no ganho de massa hepática e mostrou ser um fator de redução na replicação de hepatócitos sete dias após a hepatectomia parcial.

6 Paths of ERK5 signaling pathway regulate hepatocyte proliferation in rat liver regeneration.

Generally, extra-cellular-signal-regulated kinase 5 (ERK5) signaling pathway regulates many physiological activities, such as cell proliferation and cell differentiation. However, little is known about how ERK5 signaling pathway composed of 15 paths participates in regulating hepatocyte proliferation during liver regeneration (LR). In this study, to explore the influence ERK5 signaling pathway upon hepatocytes at gene transcription level, rat genome 230 2.0 array was used to detect expression changes of 75 related genes in isolated hepatocytes from rat regenerating liver. Bioinformatics and systems biology methods were applied to analyze the precise role of ERK5 signaling pathway in regulating hepatocyte proliferation during LR. Results showed that 62 genes were contained in the array and 22 genes were significantly changed. It was found that 6 paths were related to hepatocyte proliferation during rat LR. Among them, paths 3, 6 and 13 of ERK5 signaling pathway modulated cell cycle progression by decreasing the negative influence on ERK5 and paths 3, 4, 8 and 9 by reinforcing the positive influence on ERK5. In summary, the study shows that 22 genes and 6 paths of ERK5 signaling pathway participate in regulating proliferation of hepatocytes in rat LR.

Impact of galectin-3 deficiency on gene expression in the liver of mice 48-h post-treatment with olive oil or CC1[4]

Galectin-3 [Gal-3] is a multifunctional protein, playing a key role in many biolegical processes. Previous study demonstrated that normal hepatocytes do not express galectin-3, but this protein can be present in injured liver. The present paper aimed to assist in elucidate the biological role of galectin-3 in injured liver by CC1[4] and to clarify genes that differentially expressed in response to galectin-3 deficiency in normal and chemically injured liver of mice 48-h post-treatment with olive oil or CC1[4]. Four male wild type mice [WT] and another four galectin-3 disrupted mice [Gal-3[-/-]] were used in this experiment. The mice were fasted overnight and classified into two groups, [each group including, two WT and two Gal-3[-/-] mice] the first subgroup received in the following morning 4 ml/kg olive oil, while the second subgroup was received 8 ml/kg CC1[4] [50% in olive oil] by gavages. After 48h, the mice were anesthetized and killed to obtain blood and excise the liver. Gene's expression analysis in the liver tissue was carried out using cDNA microarray technique. The cDNA microarrays analysis revealed that 7 genes have clearly changed their levels of expression, of these 5 genes related to detoxification mechanisms are up-regulated and 2 genes related to tumor cell and amyloid protein have been down-regulated in Gal-3[-/-] mice after 48 h post-treatment with olive oil. The mice treated with CC1[4] reveled that 42 genes have clearly changed their levels of expression, of this 8 genes were up-regulated and 34 genes were down-regulated. Of the up-regulated genes were detoxification, fatty acids and lipid metabolism proteins. On the other hand, the down-regulated genes encoded proteins for xenobiotic metabolism, stress response, transcription factors, lipid metabolism, proteolysis and peptedolysis, RNA, nerve system, and immune responses proteins. This study demonstrated that changes in gene expression profile in galectin-3 deficiency mice 48-h post-treatment with CC1[4], mostly related to down-regulated different genes including, many biological processes, implying the multifunctional of galectin-3 to protect and ameliorated the liver injury induced by CC1[4] in mice

Effect of splenectomy on liver regeneration and function following partial hepatectomy: experimental study

The presence of enough remaining functioning liver parenchyma to avoid life-threatening postoperative liver failure is a major prerequisite for hepatic resection in patients with hepato biliary carcinoma. There are clinical reports which confirm the beneficial clinical effects of splenectomy on integrity of the residual liver following liver resection for hepatocellular carcinoma in cirrhotic patients with hypersplenism and portal hypertension. This experimental study was designed on hamsters to evaluate the proliferative capacity and function of the remaining liver lobes; in which splenectomy was done simultaneously with partial hepatectomy compared with those in which splenectomy was not done. Forty hamsters were divided into two groups: GI; in which partial hepatectomy was performed without splenectomy and the GIl; in which animals were subjected to partial hepatectomy with prior splenectomy. Animals from each group were subjected to liver biopsy from the remaining lobes 48, 72 hours and one week after surgery. Also, serum alanine aminotransferase [ALT] and total bilirubin were tested before, 48, 72 hours and one week after hepatectomy. Hepatic regeneration in the remaining lobes was assessed through histo-pathological study, DNA ploidy of the hepatic nuclei using computerized image analysis system and determining of the labeling index of the nuclear factor NF Kappa B [P105], a novel monoclonal antibody specific for P105 protein by immunohistochemistry. In GIl: induction of NK kappa B [PI05] labeling index showed maximum expression depending on the regenerative capacity of the remaining liver lobes. In contrast, in GI; liver regeneration was slow. Also, changes in liver function of Gil indicated that splenectomy prior hepatecotomy may minimize dysfunction in the remaining hypertrophied liver lobes

Prometeo: regeneración tisular: pifias de la naturaleza y esperanzas de la ciencia / Prometheus: tissue regeneration: natural errors and scientific hope

En el movisimo campo de las células troncales ("stem cell") y la medicina regenerativa, la búsqueda del Santo Grial de la investigación científica, es la recreacion o la inducción del renacimiento de un órgano funcional, llamese hígado, retina o riñon. En un extremo el hígado de Prometeo, de inherente capacidad para regenerarse, la demanda del órgano excede en mucho la disponibilidad de donantes. En Estados Unidos de America, 9% de los pacientes con insuficiencia hepática fallecen a la espera de un trasplante, así que la investigación en tratamientos regenerativos nunca ha tenido más fundamento y adquirido más énfasis que en estos tiempos. En el otro extremo, la retina, inexplicable olvido de la naturaleza, como otras neuronas del sistema nervioso incapaz de regenerarse a sí misma y hasta ahora, inmune a la neuroprotección y reparación después de una injuria. No obstante en un futuro no muy lejano será posible preservar y restaurar la visión en personas en las que se encuentre amenazada o se haya perdido por enfermedad o injuria del nervio óptico

In the newest field of stem cells and regenerative medicine, the quest for the Holy Grail of scientific research is the recreation or induction of rebirth of a functional organism, such as the liver, retina o kidney. At one end liver of Prometheus with its inherent capacity to regenerate, has a demand that greatly exceeds the availability of donors. In the United States of America, 9% of patients with liver failure die waiting for a transplant, so research in regenerative treatment has never had more importance or acquired greater emphasis than at this time. At the other end, the retina, inexplicable oblivion of nature, is, as other neurons of the central nervous system, unable to regenerate itself and so far, immune to neuroprotection and repair after an injury. Nevertheless, in the future it will be possible, however, to preserve and restore vision in people whose optic nerve are threatened or have been lost due to illness or injury

Mitochondrial ultrastructure & release of proteins during liver regeneration.

BACKGROUND & OBJECTIVES: It has been reported that some proteins are released from mitochondria during liver regeneration after partial hepatectomy (PH), but the relationship between proteins release and mitochondrial permeability transition (MPT) remains unclear. We undertook this study to demonstrate the changes of mitochondrial ultrastructure and proteins release during liver regeneration and to determine the relationship between proteins release and MPT in liver regeneration in rats. METHODS: After PH and administration of cyclosporin-A (CsA, a specific inhibitor of MPT), ultrastructural morphology of mitochondria in the remnant liver were determined by electron microscopy. Catalytic activity of mitochondrial and cytosolic proteins including aspartate aminotransferase (AST) and glutamic acid dehydrogenase (GDH) was measured. RESULTS: The liver mitochondria at 24 and 72 h were quite variable in morphology and ultrastructure. The enzyme activities of AST and GDH in cytosol released from mitochondrial matrix changed significantly at 24 and 72 h. CsA can inhibit the permeability of mitochondria partly at the same time. INTERPRETATION & CONCLUSIONS: The changes of mitochondria in ultrastructure reflected the feature of MPT, and the changes of enzymes activities released from mitochondrial matrix were consistent with those of mitochondrial ultrastructure. CsA can inhibit these changes to some extent. There was a close relationship of MPT with mitochondrial ultrastructure and proteins release during liver regeneration.