Blocking the HGF-MET pathway induces resolution of neutrophilic inflammation by promoting neutrophil apoptosis and efferocytosis.

Inflammation resolution is an active process that involves cellular events such as apoptosis and efferocytosis, which are key steps in the restoration of tissue homeostasis. Hepatocyte growth factor (HGF) is a growth factor mostly produced by mesenchymal-origin cells and has been described to act via MET receptor tyrosine kinase. The HGF/MET axis is essential for determining the progression and severity of inflammatory and immune-mediated disorders. Here, we investigated the effect of blocking the HGF/MET signalling pathway by PF-04217903 on the resolution of established models of neutrophilic inflammation. In a self-resolving model of gout induced by MSU crystals, HGF expression on periarticular tissue peaked at 12 h, the same time point that neutrophils reach their maximal accumulation in the joints. The HGF/MET axis was activated in this model, as demonstrated by increased levels of MET phosphorylation in neutrophils (Ly6G+ cells). In addition, the number of neutrophils was reduced in the knee exudate after PF-04217903 treatment, an effect accompanied by increased neutrophil apoptosis and efferocytosis and enhanced expression of Annexin A1, a key molecule for inflammation resolution. Reduced MPO activity, IL-1ß and CXCL1 levels were also observed in periarticular tissue. Importantly, PF-04217903 reduced the histopathological score and hypernociceptive response. Similar findings were obtained in LPS-induced neutrophilic pleurisy. In human neutrophils, the combined use of LPS and HGF increased MET phosphorylation and provided a prosurvival signal, whereas blocking MET with PF-04217903 induced caspase-dependent neutrophil apoptosis. Taken together, these data demonstrate that blocking HGF/MET signalling may be a potential therapeutic strategy for inducing the resolution of neutrophilic inflammatory responses.

Hepatocyte growth factor reverses cholemic nephropathy associated with α-naphthylisothiocyanate-induced cholestasis in mice.

Hepatocyte growth factor (HGF) has been proved to protect the liver against α-naphthylisothiocyanate (ANIT)-induced cholestasis by acting as an antioxidant agent and redirecting toxic biliary solutes towards blood for urinary excretion. However, this may represent an additional potential risk for kidney integrity, which is already compromised by the cholestatic process itself (cholemic nephropathy). Therefore, in the present work, we studied the renal damage caused by ANIT-induced cholestasis and whether it is aggravated or, on the contrary, counteracted by HGF; if the latter holds, the involvement of its antioxidant properties will be ascertained. ANIT-induced cholestatic deleterious renal effects were corroborated by the presence of urine bile salts, impairment of renal function, and the alterations of renal damage markers, such as HSP72, creatinine clearance, and albuminuria. HGF fully reverted all these, and the cast formation in the tubules was significantly decreased. These findings were associated with the control of renal oxidative stress. In summary, despite HGF enhancing the overload of potentially harmful biliary constituents that the kidney should remove from the bloodstream as an alternative depuration organ in cholestasis, it simultaneously protects the kidney from this damage by counteracting the prooxidant effects resulting from this harmful exposure.

HGF induces protective effects in α-naphthylisothiocyanate-induced intrahepatic cholestasis by counteracting oxidative stress.

Cholestasis is a clinical syndrome common to a large number of hepatopathies, in which either bile production or its transit through the biliary tract is impaired due to functional or obstructive causes; the consequent intracellular retention of toxic biliary constituents generates parenchyma damage, largely via oxidative stress-mediated mechanisms. Hepatocyte growth factor (HGF) and its receptor c-Met represent one of the main systems for liver repair damage and defense against hepatotoxic factors, leading to an antioxidant and repair response. In this study, we evaluated the capability of HGF to counteract the damage caused by the model cholestatic agent, α-naphthyl isothiocyanate (ANIT). HGF had clear anti-cholestatic effects, as apparent from the improvement in both bile flow and liver function test. Histology examination revealed a significant reduction of injured areas. HGF also preserved the tight-junctional structure. These anticholestatic effects were associated with the induction of basolateral efflux ABC transporters, which facilitates extrusion of toxic biliary compounds and its further alternative depuration via urine. The biliary epithelium seems to have been also preserved, as suggested by normalization in serum GGT levels, CFTR expression and cholangyocyte primary cilium structure our results clearly show for the first time that HGF protects the liver from a cholestatic injury.

Hepatocyte growth factor enhances the clearance of a multidrug-resistant Mycobacterium tuberculosis strain by high doses of conventional chemotherapy, preserving liver function.

Tuberculosis (TB) is one of the deadliest infectious diseases in humankind history. Although, drug sensible TB is slowly decreasing, at present the rise of TB cases produced by multidrug-resistant (MDR) and extensively drug-resistant strains is a big challenge. Thus, looking for new therapeutic options against these MDR strains is mandatory. In the present work, we studied, in BALB/c mice infected with MDR strain, the therapeutic effect of supra-pharmacological doses of the conventional primary antibiotics rifampicin and isoniazid (administrated by gavage or intratracheal routes), in combination with recombinant human hepatocyte growth factor (HGF). This high dose of antibiotics administered for 3 months, overcome the resistant threshold of the MDR strain producing a significant reduction of pulmonary bacillary loads but induced liver damage, which was totally prevented by the administration of HGF. To address the long-term efficiency of this combined treatment, groups of animals after 1 month of treatment termination were immunosuppressed by glucocorticoid administration and, after 1 month, mice were euthanized, and the bacillary load was determined in lungs. In comparison with animals treated only with a high dose of antibiotics, animals that received the combined treatment showed significantly lower bacterial burdens. Thus, treatment of MDR-TB with very high doses of primary antibiotics particularly administrated by aerial route can produce a very good therapeutic effect, and its hepatic toxicity can be prevented by the administration of HGF, becoming in a new treatment modality for MDR-TB.

Therapeutic Effect of HGF on NASH Mice Through HGF/c-Met and JAK2-STAT3 Signalling Pathway.

INTRODUCTION AND AIM: Hepatocyte growth factor (HGF) has been shown to ameliorate liver inflammation and fibrosis; however, the mechanism underlying its effects in non-alcoholic steatohepatitis (NASH) is unclear. This study aimed to analyse the relationship between the JAK2-STAT3 signalling pathway and the ameliorating effect of HGF on NASH. MATERIAL AND METHODS: Mice were fed a high-fat diet (HFD) for 16 weeks, and then plasma and hepatic tissues were collected. Histological and clinical chemistry assays were performed to assess liver disease. The mRNA and protein levels of JAK2, STAT3, and c-Met were assessed by real-time PCR and western blotting, respectively. RESULTS: Serum ALT, AST, and TG levels were increased in NASH mice. Histological analysis showed different degrees of steatosis, inflammatory infiltrates, and fibrosis in HFD animals. Exogenous administration of recombinant human (rh) HGF via the tail vein for 14 days markedly decreased ALT and AST to levels lower than those in the control group. Compared with the levels in HFD mice, c-Met, p-c-Met, JAK2, p-JAK2, and p-STAT3 levels were increased in mice that were administered HGF (P < 0.05). Furthermore, silencing of HGF or blocking of its receptor c-Met affected JAK2 and STAT3 protein phosphorylation. CONCLUSIONS: Excess HGF highly probable improved NASH liver function. Combined with its ligand, c-Met, HGF may promote the phosphorylation of JAK2-STAT3 and inhibit inflammation in NASH. Therefore, it may be potentially useful treatment for NASH.

Recombinant human hepatocyte growth factor provides protective effects in cerulein-induced acute pancreatitis in mice.

Acute pancreatitis is a multifactorial disease associated with profound changes of the pancreas induced by release of digestive enzymes that lead to increase in proinflammatory cytokine production, excessive tissue necrosis, edema, and bleeding. Elevated levels of hepatocyte growth factor (HGF) and its receptor c-Met have been observed in different chronic and acute pancreatic diseases including experimental models of acute pancreatitis. In the present study, we investigated the protective effects induced by the recombinant human HGF in a mouse model of cerulein-induced acute pancreatitis. Pancreatitis was induced by 8 hourly administrations of supramaximal cerulein injections (50 µg/kg, ip). HGF treatment (20 µg/kg, iv), significantly attenuated lipase content and amylase activity in serum as well as the degree inflammation and edema overall leading to less severe histologic changes such as necrosis, induced by cerulein. Protective effects of HGF were associated with activation of pro-survival pathways such as Akt, Erk1/2, and Nrf2 and increase in executor survival-related proteins and decrease in pro-apoptotic proteins. In addition, ROS content and lipid peroxidation were diminished, and glutathione synthesis increased in pancreas. Systemic protection was observed by lung histology. In conclusion, our data indicate that HGF exerts an Nrf2 and glutathione-mediated protective effect on acute pancreatitis reflected by a reduction in inflammation, edema, and oxidative stress.

HGF potentiates extracellular matrix-driven migration of human myoblasts: involvement of matrix metalloproteinases and MAPK/ERK pathway.

BACKGROUND: The hepatocyte growth factor (HGF) is required for the activation of muscle progenitor cells called satellite cells (SC), plays a role in the migration of proliferating SC (myoblasts), and is present as a soluble factor during muscle regeneration, along with extracellular matrix (ECM) molecules. In this study, we aimed at determining whether HGF is able to interact with ECM proteins, particularly laminin 111 and fibronectin, and to modulate human myoblast migration. METHODS: We evaluated the expression of the HGF-receptor c-Met, laminin, and fibronectin receptors by immunoblotting, flow cytometry, or immunofluorescence and used Transwell assays to analyze myoblast migration on laminin 111 and fibronectin in the absence or presence of HGF. Zymography was used to check whether HGF could modulate the production of matrix metalloproteinases by human myoblasts, and the activation of MAPK/ERK pathways was evaluated by immunoblotting. RESULTS: We demonstrated that human myoblasts express c-Met, together with laminin and fibronectin receptors. We observed that human laminin 111 and fibronectin have a chemotactic effect on myoblast migration, and this was synergistically increased when low doses of HGF were added. We detected an increase in MMP-2 activity in myoblasts treated with HGF. Conversely, MMP-2 inhibition decreased the HGF-associated stimulation of cell migration triggered by laminin or fibronectin. HGF treatment also induced in human myoblasts activation of MAPK/ERK pathways, whose specific inhibition decreased the HGF-associated stimulus of cell migration triggered by laminin 111 or fibronectin. CONCLUSIONS: We demonstrate that HGF induces ERK phosphorylation and MMP production, thus stimulating human myoblast migration on ECM molecules. Conceptually, these data state that the mechanisms involved in the migration of human myoblasts comprise both soluble and insoluble moieties. This should be taken into account to optimize the design of therapeutic cell transplantation strategies by improving the migration of donor cells within the host tissue, a main issue regarding this approach.

Hepatocyte growth factor upregulates nexilin gene expression in cardiomyocytes via JNK pathway.

Hepatocyte growth factor (HGF) is a protective factor in myocardial injury, but its mechanisms of action have not yet been fully elucidated. Nexilin, which locates specifically to the Z-disc, is a novel Z-disc protein that enables the Z-discs to persistently withstand the extreme mechanical forces generated during muscle contraction. Therefore, we investigated the role of HGF in modulating nexilin expression in hypoxia-reoxygenation (H/R)-treated cardiomyocytes. We cultured neonatal cardiomyocytes and treated them with HGF. The mRNA and protein levels of nexilin were determined by RT-PCR and Western blotting. H/R treatment decreased nexilin mRNA expression and nexilin protein levels in cardiomyocytes. Furthermore, treatment with HGF upregulated nexilin expression and the JNK inhibitor SP600125 partly inhibited HGF-induced nexilin upregulation. In conclusion, our results suggest that ischemia-reperfusion injury may downregulate nexilin expression in cardiomyocytes, and HGF may exert its protective role during myocardial ischemic injury through upregulation of nexilin expression in cardiomyocytes.

Hepatocyte growth factor protects against isoniazid/rifampicin-induced oxidative liver damage.

The worldwide increment of multidrug- and extensively drug-resistant tuberculosis has emphasized the importance of looking for new options in therapeutics. Long-time usage or higher doses of isoniazid and rifampicin have been considered for the treatment of multidrug-resistant tuberculosis; however, the risk of liver failure is proportionally increased. Hepatocyte growth factor (HGF) is a multitask growth factor that stimulates both antiapoptotic and antioxidant responses that counteract the toxic effects of drug metabolism in the liver. The present work was focused to address the antioxidant and antiapoptotic effects of HGF on isoniazid- and rifampicin-induced hepatotoxicity. BALB/c mice were subjected to rifampicin (150mg/kg, intragavage [ig]) plus isoniazid (75mg/kg, ig) for 7 days. Increments in alanine aminotransferase activity, steatosis, apoptosis, and oxidative stress markers were found in animals. Recombinant HGF (iv) prevented all the harmful effects by increasing the activation of Erk1/2 and PKCδ signaling pathways and glutathione (GSH) synthesis. Furthermore, inhibition of endogenous HGF with anti-HGF antibody (iv) enhanced the isoniazid- and rifampicin-induced oxidative stress damage and decreased the GSH content, aggravating liver damage. In conclusion, HGF demonstrated to be a good protective factor against antituberculosis drug-induced hepatotoxicity and could be considered a good adjuvant factor for the use of high doses of or the reintroduction of these antituberculosis drugs.

Transmigration of neural stem cells across the blood brain barrier induced by glioma cells.

Transit of human neural stem cells, ReNcell CX, through the blood brain barrier (BBB) was evaluated in an in vitro model of BBB and in nude mice. The BBB model was based on rat brain microvascular endothelial cells (RBMECs) cultured on Millicell inserts bathed from the basolateral side with conditioned media (CM) from astrocytes or glioma C6 cells. Glioma C6 CM induced a significant transendothelial migration of ReNcells CX in comparison to astrocyte CM. The presence in glioma C6 CM of high amounts of HGF, VEGF, zonulin and PGE2, together with the low abundance of EGF, promoted ReNcells CX transmigration. In contrast cytokines IFN-α, TNF-α, IL-12p70, IL-1ß, IL-6, IL-8 and IL-10, as well as metalloproteinases -2 and -9 were present in equal amounts in glioma C6 and astrocyte CMs. ReNcells expressed the tight junction proteins occludin and claudins 1, 3 and 4, and the cell adhesion molecule CRTAM, while RBMECs expressed occludin, claudins 1 and 5 and CRTAM. Competing CRTAM mediated adhesion with soluble CRTAM, inhibited ReNcells CX transmigration, and at the sites of transmigration, the expression of occludin and claudin-5 diminished in RBMECs. In nude mice we found that ReNcells CX injected into systemic circulation passed the BBB and reached intracranial gliomas, which overexpressed HGF, VEGF and zonulin/prehaptoglobin 2.

Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy

Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [³H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of β-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy.

Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy.

Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [³H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of ß-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy.

Mechanisms of RON-mediated epithelial-mesenchymal transition in MDCK cells through the MAPK pathway

The epithelial-mesenchymal transition (EMT) is involved in neoplastic metastasis, and the RON protein may be involved. In the present study, we determined the role and the mechanisms of action of RON in EMT in Madin-Darby canine kidney (MDCK) cells by Western blot and cell migration analysis. Activation of RON by macrophage stimulating protein (MSP) results in cell migration and initiates changes in the morphology of RON-cDNA-transfected MDCK cells. The absence of E-cadherin, the presence of vimentin and an increase in Snail were observed in RE7 cells, which were derived from MDCK cells transfected with wt-RON, compared with MDCK cells. Stimulation of RE7 cells with MSP resulted in increased migration (about 69 percent of the wounded areas were covered) as well as increased activation of extracellular signal-regulated kinase 1/2 (Erk1/2) and glycogen synthase kinase-3β (GSK-3β; the percent of the activation ratio was 143.6/599.8 percent and 512.4 percent, respectively), which could be inhibited with an individual chemical inhibitor PD98059 (50 μM) specific to MAPK/ERK kinase (the percent inhibition was 98.9 and 81.2 percent, respectively). Thus, the results indicated that RON protein could mediate EMT in MDCK cells via the Erk1/2 pathway. Furthermore, GSK-3β regulates the function of Snail in controlling EMT by this pathway.

Mechanisms of RON-mediated epithelial-mesenchymal transition in MDCK cells through the MAPK pathway.

The epithelial-mesenchymal transition (EMT) is involved in neoplastic metastasis, and the RON protein may be involved. In the present study, we determined the role and the mechanisms of action of RON in EMT in Madin-Darby canine kidney (MDCK) cells by Western blot and cell migration analysis. Activation of RON by macrophage stimulating protein (MSP) results in cell migration and initiates changes in the morphology of RON-cDNA-transfected MDCK cells. The absence of E-cadherin, the presence of vimentin and an increase in Snail were observed in RE7 cells, which were derived from MDCK cells transfected with wt-RON, compared with MDCK cells. Stimulation of RE7 cells with MSP resulted in increased migration (about 69% of the wounded areas were covered) as well as increased activation of extracellular signal-regulated kinase 1/2 (Erk1/2) and glycogen synthase kinase-3ß (GSK-3ß; the percent of the activation ratio was 143.6/599.8% and 512.4%, respectively), which could be inhibited with an individual chemical inhibitor PD98059 (50 µM) specific to MAPK/ERK kinase (the percent inhibition was 98.9 and 81.2%, respectively). Thus, the results indicated that RON protein could mediate EMT in MDCK cells via the Erk1/2 pathway. Furthermore, GSK-3ß regulates the function of Snail in controlling EMT by this pathway.

The role of growth factors on renal tubular cells submitted to hypoxia and deprived of glucose.

BACKGROUND: In acute renal failure (ARF) renal tubular cell death and detachment can be induced by necrotic and apoptotic mechanisms. Several studies have demonstrated some benefits of the use of growth factors in experimental models of ARF. METHODS: MDCK cells were cultured in a glucose-free medium for 24h and were submitted to hypoxia (PO2 around 35 mmHg) for additional 24 h. To evaluate the possible protective role of growth factors, EGF, IGF-I or HGF were added to the medium (20 ng mL). LDH release, viability (acridine orange and ethidium bromide dyes) and quantification of apoptotic cells (Hoechst 33342 dye fluorescence) were determined. RESULTS: In the injury group, an increase on LDH release (60% vs. 3%) and on number of apoptotic cells (22% vs. 0.2%) which was associated with a reduced cell viability (61% vs. 94%) when compared with controls. Only HGF, not EGF or IGF-I, was able to protect cells from injury. HGF caused a significant reduction on LDH release (30%) and on number of apoptotic cells (5%), with an increase on viability cellular (79%). CONCLUSIONS: HGF decreases cell death on MDCK cells after hypoxic-induced injury, probably acting in both necrotic and apoptotic mechanisms.

Effect of tissue and plasma factors on kidney proliferation.

Liver extract, plasma from intact mice, ES2 tumour extract and plasma from tumour bearing mice has an inhibiting effect on the mitotic activity of hepatocytes and duodenal enterocytes. In the present experiments, the effect of these treatments on the mitotic activity of renal tubular cells was studied. C3HS 28 day-old male mice, standardized for periodicity analysis were used. The determination of normal mitotic circadian curve of the renocytes was done. A second batch of mice were injected with 0.01 ml/gr of either liver extract, plasma from intact mice, ES2 tumour extract or plasma from tumour bearing mice, at 16:00 hours and controlled at 08:00, 12:00 and 16:00 hs during 2 consecutive days post treatment. Colchicine (2 micrograms/gr) was injected 4 hours before killing. Kidneys were processed for histology and mitotic index determinations. Results were expressed as colchicine metaphases per 1000 nuclei, and showed that mitotic activity values of treated animals were significantly lower than those of controls. In conclusion, mitotic activity inhibition of renocytes may be due to some non specific plasmatic and/or tissue factors.

Effect of tissue and plasma factors on kidney proliferation

Liver extract, plasma from intact mice, ES2 tumour extract and plasma from tumour bearing mice has an inhibiting effect on the mitotic activity of hepatocytes and duodenal enterocytes. In the present experiments, the effect of these treatments on the mitotic activity of renal tubular cells was studied. C3HS 28 day-old male mice, standardized for periodicity analysis were used. The determination of normal mitotic circadian curve of the renocytes was done. A second batch of mice were injected with 0.01 ml/gr of either liver extract, plasma from intact mice, ES2 tumour extract or plasma from tumour bearing mice, at 16:00 hours and controlled at 08:00, 12:00 and 16:00 hs during 2 consecutive days post treatment. Colchicine (2 micrograms/gr) was injected 4 hours before killing. Kidneys were processed for histology and mitotic index determinations. Results were expressed as colchicine metaphases per 1000 nuclei, and showed that mitotic activity values of treated animals were significantly lower than those of controls. In conclusion, mitotic activity inhibition of renocytes may be due to some non specific plasmatic and/or tissue factors.

Effect of tissue and plasma factors on kidney proliferation

Liver extract, plasma from intact mice, ES2 tumour extract and plasma from tumour bearing mice has an inhibiting effect on the mitotic activity of hepatocytes and duodenal enterocytes. In the present experiments, the effect of these treatments on the mitotic activity of renal tubular cells was studied. C3HS 28 day-old male mice, standardized for periodicity analysis were used. The determination of normal mitotic circadian curve of the renocytes was done. A second batch of mice were injected with 0.01 ml/gr of either liver extract, plasma from intact mice, ES2 tumour extract or plasma from tumour bearing mice, at 16:00 hours and controlled at 08:00, 12:00 and 16:00 hs during 2 consecutive days post treatment. Colchicine (2 micrograms/gr) was injected 4 hours before killing. Kidneys were processed for histology and mitotic index determinations. Results were expressed as colchicine metaphases per 1000 nuclei, and showed that mitotic activity values of treated animals were significantly lower than those of controls. In conclusion, mitotic activity inhibition of renocytes may be due to some non specific plasmatic and/or tissue factors.(AU)

Estudio de la regeneración hepática utilizando un nuevo modelo in vivo: "la hepatectomía total temporaria" / Study of liver regeneration with original model in vivo: \"temporary total hepatectomy\"

Luego de una hepatectomía parcial, se producen cambios metabólicos y expresión de protooncogenes en el hígado, con la aparición de substancias estimulantes en sangre periférica, que provienen de dentro (factores intrahepáticos) y fuera (factores extrahepáticos) del hígado. Si bien una señal para la regeneración está siempre presente, no es claro cómo estos factores interactúan para estimular la síntesis de ADN durante las primeras 24 horas. Es necesario conocer si estos factores están conectados entre sí, para poder interpretar correctamente el proceso regenerativo hepático y eventualmente estimular aún más la regeneración. Para responder a estos interrogantes hemos sometido a ratas machos tipo Wistar a una "Hepatectomía Total Temporaria", funcional, mediante la confección de un shunt-porto-cava con vena homóloga, hepatectomía parcial del 30 por ciento y exclusión de los lóbulos anteriores. Luego de 3 horas los lóbulos son reperfundidos y a las 22 horas se inyectan 50 µCi de 3H thymidina y el hígado es removido 2 horas después. Posterior a una "Hepatectomía Total Temporaria", la síntesis de ADN (10975 ñ 2599 DPM/mgr DNA) fue menor que en ratas sometidas a una hepatectomía del 30 por ciento (20150 ñ 2540 P<0,01) y marcadamente inferior que luego de una hepatectomía parcial del 70 por ciento (160315 ñ 22293 P<0,001). Mediante este original modelo queda demostrado que no existe una desconexión entre los factores intra y extra hepáticos que inician el impulso regenerativo por lo que la estimulación post hepatectomía debería hacerse teniendo en cuenta ambos factores

Estudio de la regeneración hepática utilizando un nuevo modelo in vivo: "la hepatectomía total temporaria" / Study of liver regeneration with original model in vivo: "temporary total hepatectomy"

Luego de una hepatectomía parcial, se producen cambios metabólicos y expresión de protooncogenes en el hígado, con la aparición de substancias estimulantes en sangre periférica, que provienen de dentro (factores intrahepáticos) y fuera (factores extrahepáticos) del hígado. Si bien una señal para la regeneración está siempre presente, no es claro cómo estos factores interactúan para estimular la síntesis de ADN durante las primeras 24 horas. Es necesario conocer si estos factores están conectados entre sí, para poder interpretar correctamente el proceso regenerativo hepático y eventualmente estimular aún más la regeneración. Para responder a estos interrogantes hemos sometido a ratas machos tipo Wistar a una "Hepatectomía Total Temporaria", funcional, mediante la confección de un shunt-porto-cava con vena homóloga, hepatectomía parcial del 30 por ciento y exclusión de los lóbulos anteriores. Luego de 3 horas los lóbulos son reperfundidos y a las 22 horas se inyectan 50 ACi de 3H thymidina y el hígado es removido 2 horas después. Posterior a una "Hepatectomía Total Temporaria", la síntesis de ADN (10975 ñ 2599 DPM/mgr DNA) fue menor que en ratas sometidas a una hepatectomía del 30 por ciento (20150 ñ 2540 P<0,01) y marcadamente inferior que luego de una hepatectomía parcial del 70 por ciento (160315 ñ 22293 P<0,001). Mediante este original modelo queda demostrado que no existe una desconexión entre los factores intra y extra hepáticos que inician el impulso regenerativo por lo que la estimulación post hepatectomía debería hacerse teniendo en cuenta ambos factores (AU)