Liver growth factor as a tissue regenerating factor in neurodegenerative diseases.

Liver growth factor (LGF) is a hepatic mitogen purified by our group in 1986. In the following years we demonstrated its activity both in "in vivo" and "in vitro" systems, stimulating hepatocytes mitogenesis as well as liver regeneration in several models of liver injury. Furthermore, we established its chemical composition (albumin-bilirubin complex) and its mitogenic actions in liver. From 2000 onwards we used LGF as a tissue regenerating factor in several models of extrahepatic diseases. The use of Liver growth factor as a neural tissue regenerator has been recently protected (Patent No US 2014/8,642,551 B2). LGF administration stimulates neurogenesis and neuron survival, promotes migration of newly generated neurons, and induces the outgrowth of striatal dopaminergic terminals in 6-hidroxydopamine-lesioned rats. Furthermore, LGF treatment raises striatal dopamine levels and protects dopaminergic neurons in hemiparkinsonian animals. LGF also stimulates survival of grafted foetal neural stem cells in the damaged striatum, reduces rotational behaviour and improves motor coordination. Interestingly, LGF also exerts a neuroprotective role both in an experimental model of cerebellar ataxia and in a model of Friedrich´s ataxia. Microglia seem to be the cellular target of LGF in the CNS. Moreover, the activity of the factor could be mediated by the stimulation of MAPK´s signalling pathway and by regulating critical proteins for cell survival, such as Bcl-2 and phospho-CREB. Since the factor shows neuroprotective and neurorestorative effects we propose LGF as a patented novel therapeutic tool that may be useful for the treatment of Parkinson´s disease and cerebellar ataxias. Currently, our studies have been extended to other neurological disorders such as Alzheimer's disease (Patent No: US 2014/0113859 A1).

Liver growth factor treatment reverses emphysema previously established in a cigarette smoke exposure mouse model.

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease largely associated with cigarette smoke exposure (CSE) and characterized by pulmonary and extrapulmonary manifestations, including systemic inflammation. Liver growth factor (LGF) is an albumin-bilirubin complex with demonstrated antifibrotic, antioxidant, and antihypertensive actions even at extrahepatic sites. We aimed to determine whether short LGF treatment (1.7 µg/mouse ip; 2 times, 2 wk), once the lung damage was established through the chronic CSE, contributes to improvement of the regeneration of damaged lung tissue, reducing systemic inflammation. We studied AKR/J mice, divided into three groups: control (air-exposed), CSE (chronic CSE), and CSE + LGF (LGF-treated CSE mice). We assessed pulmonary function, morphometric data, and levels of various systemic inflammatory markers to test the LGF regenerative capacity in this system. Our results revealed that the lungs of the CSE animals showed pulmonary emphysema and inflammation, characterized by increased lung compliance, enlargement of alveolar airspaces, systemic inflammation (circulating leukocytes and serum TNF-α level), and in vivo lung matrix metalloproteinase activity. LGF treatment was able to reverse all these parameters, decreasing total cell count in bronchoalveolar lavage fluid and T-lymphocyte infiltration in peripheral blood observed in emphysematous mice and reversing the decrease in monocytes observed in chronic CSE mice, and tends to reduce the neutrophil population and serum TNF-α level. In conclusion, LGF treatment normalizes the physiological and morphological parameters and levels of various systemic inflammatory biomarkers in a chronic CSE AKR/J model, which may have important pathophysiological and therapeutic implications for subjects with stable COPD.

Liver growth factor treatment reverses vascular and plasmatic oxidative stress in spontaneously hypertensive rats.

BACKGROUND: Liver growth factor (LGF) is an albumin-bilirubin complex with antioxidant actions in vitro. In spontaneously hypertensive rats (SHRs), short LGF treatment exerts antihypertensive and antifibrotic effects. METHOD: We aimed to determine if LGF treatment (4 i.p. injections, 4.5 µg/rat over 12 days) reduces oxidative stress in SHRs using Wistar-Kyoto (WKY) as control strain. We assessed the following: plasma oxidative stress biomarkers [protein-bound malondialdehyde (MDA); protein carbonyls and advanced glycation end products (AGEs)]; superoxide anion basal production in carotid artery-derived vascular smooth muscle cells (VSMCs) detected by dihydroethidium and confocal microscopy; and expression (western blot) and activities (spectroscopic methods) of NADPH and xanthine oxidases, CuZn, Mn and extracellular superoxide dismutases (SODs) and catalase in carotid arteries. RESULTS: LGF treatment had the following effects: reversed the increase in plasma MDA and protein carbonyls and VSMC superoxide anion levels observed in SHRs, without any effect on WKY strain; reversed the alterations in SHR vascular p22phox expression as well as NADPH oxidase, xanthine oxidase and catalase activities; had no effect on vascular CuZn-SOD and Mn-SOD expression or total SOD activity; and reversed the elevation in SHR vascular glycated/free extracellular-SOD expression ratio and plasma glucose without changes in plasma AGEs. CONCLUSION: LGF treatment of SHRs normalizes the level of plasma oxidative stress biomarkers through a reduction of vascular superoxide anion produced by NADPH and xanthine oxidases. These effects might be linked to the cardiovascular regenerative actions of LGF.

Liver growth factor treatment restores cell-extracellular matrix balance in resistance arteries and improves left ventricular hypertrophy in SHR.

Liver growth factor (LGF) is an endogenous albumin-bilirubin complex with antihypertensive effects in spontaneously hypertensive rats (SHR). We assessed the actions of LGF treatment on SHR mesenteric resistance and intramyocardial arteries (MRA and IMA, respectively), heart, and vascular smooth muscle cells (VSMC). SHR and Wistar-Kyoto (WKY) rats treated with vehicle or LGF (4.5 µg LGF/rat, 4 ip injections over 12 days) were used. Intra-arterial blood pressure was measured in anesthetized rats. The heart was weighted and paraffin-embedded. Proliferation, ploidy, and fibronectin deposition were studied in carotid artery-derived VSMC by immunocytochemistry. In MRA, we assessed: 1) geometry and mechanics by pressure myography; 2) function by wire myography; 3) collagen by sirius red staining and polarized light microscopy, and 4) elastin, cell density, nitric oxide (NO), and superoxide anion by confocal microscopy. Heart sections were used to assess cell density and collagen content in IMA. Left ventricular hypertrophy (LVH) regression was assessed by echocardiography. LGF reduced blood pressure only in SHR. LGF in vitro or as treatment normalized the alterations in proliferation and fibronectin in SHR-derived VSMC with no effect on WKY cells. In MRA, LGF treatment normalized collagen, elastin, and VSMC content and passive mechanical properties. In addition, it improved NO availability through reduction of superoxide anion. In IMA, LGF treatment normalized perivascular collagen and VSMC density, improving the wall-to-lumen ratio. Paired experiments demonstrated a partial regression of SHR LVH by LGF treatment. The effective cardiovascular antifibrotic and regenerative actions of LGF support its potential in the treatment of hypertension and its complications.

Effect of liver growth factor on both testicular regeneration and recovery of spermatogenesis in busulfan-treated mice.

BACKGROUND: Some adult stem cells persist in adult tissue; however, we do not know how to stimulate stem cells in adults to heal injuries. Liver growth factor (LGF) is a biliprotein with hepatic mitogen activity. Its concentration increases markedly in the presence of any type of liver injury, and it shows in vivo therapeutic biological activity at extrahepatic sites. METHODS: We have analyzed the effect of LGF on the replenishment of germinal cells in the testes of mice injected with busulfan, a common cancer drug that also specifically affects germ line stem cells and spermatogonia. We determined the testicular and epididymal weight, spermatozoal concentration in the epididymis and sperm motility, and performed a histological analysis. RESULTS: Intraperitoneal administration of LGF was able to partially restore spermatogenesis, as well as sperm production and motility, in mice sterilized with busulfan. LGF treatment in busulfan-treated animals that have suffered a disruption of spermatogenesis can accelerate the reactivation of this process in most of the tubules, as shown in the histological analysis. CONCLUSIONS: Our results suggest a potential use of LGF in the mobilization of testicular stem cells and in the restoration of spermatogenesis after busulfan-induced damage to the testicular germinal epithelium.

Sex-dependent effect of liver growth factor on atherosclerotic lesions and fatty liver disease in apolipoprotein E knockout mice.

OBJECTIVE: Since the hepatic mitogen, liver growth factor (LGF), improves vascular structure and function in a hypertensive rat model and exhibits antioxidant activity, it may play a role in the development of atherosclerosis. METHODS: To test this hypothesis, 14 male and 11 female apolipoprotein E (apoE)-deficient mice with a C57BL/6J genetic background were injected intraperitoneally twice a week with 1.7 microg of LGF per mouse for ten weeks. Plasma carbohydrates, inflammatory and lipid parameters, apolipoproteins A-I and A-II and paraoxonase activity were assessed at the end of the experimental period. Histological and chemical analyses of the livers and quantification of aortic atherosclerotic lesions were also carried out. RESULTS: LGF administration changed neither plasma lipid nor inflammatory parameters. ApoA-I and arylesterase activity were not affected by LGF either, while apoA-II decreased significantly in males but not in females. Plasma apoA-II correlated positively with liver fat in males but negatively in females. Atherosclerotic area lesions in males receiving LGF were 25% lower than in control mice. Likewise, a significant reduction of fatty liver disease was also observed in males in association with decreased levels of insulin, leptin and resistin. CONCLUSION: These results indicate that administration of LGF modulates atherosclerotic lesions in a sex-dependent manner. This effect is independent of plasma cholesterol, triglycerides, IL-6, MCP-1 and TNF-alpha and is related to a remodelling of HDL particles characterised by a decrease in apoA-II induced by changes in hepatic mRNA expression. Hence, LGF administration could be used as a safe alternative to control fatty liver disease and atherosclerosis in males.

Liver growth factor antifibrotic activity in vivo is associated with a decrease in activation of hepatic stellate cells.

The antifibrotic activity of Liver Growth Factor (LGF), a liver mitogen, was previously demonstrated in several models of rat liver fibrosis and even in extrahepatic sites, such as carotid artery in hypertensive rats and rat CdCl2-induced lung fibrosis. In the present study, we have attempted to examine in depth its mechanism of antifibrotic action in bile duct-ligated (BDL) rats, with special emphasis on its activity in fibrogenic liver cells. BDL rats received either LGF 9 microg/week for 2 or 3 weeks (BDL+LGF, n=20/group) or saline (BDL+S, n=20/group), at times 0, week 2, or week 5 after operation. Groups were compared in terms of liver alpha-smooth muscle actin (SMA) content (western blotting and immunohistochemistry), hepatic apoptosis, liver desmin content (western blotting), and serum endothelin-1 (ELISA). LGF produced a marked decrease in liver alpha-SMA content compared with saline-injected rats, especially evident at longer times (5w and 8w; p<0.05). Moreover, LGF did not seem to influence HSC proliferation, as shown by measuring liver desmin content. The antifibrotic activity exerted by LGF seems to be closely related to a modulation of the activation state of fibrogenic liver cells (activated HSC and myofibroblasts) in BDL rats.

Antioxidant activity of liver growth factor, a bilirubin covalently bound to albumin.

We previously reported that treatment of spontaneously hypertensive rats (SHR) with liver growth factor (LGF), an albumin-bilirubin complex with a covalent bond, reduces blood pressure, improves nitric oxide (NO)-dependent vasodilatation, and exerts vascular antifibrotic actions. Because bilirubin, albumin, and albumin-bound bilirubins have antioxidant properties, we hypothesize that LGF might exert its cardiovascular actions through an antioxidant mechanism. We have tested in vitro the capacity of LGF to scavenge ABTS cation and peroxyl and hydroxyl radicals and to protect vascular NO from degradation by superoxide anion. We have also compared the antioxidant capacity of LGF with that of its molecular components albumin and bilirubin and the reference antioxidant trolox. LGF exhibited antioxidant capacity against all free radicals tested at lower concentrations than albumin, bilirubin, and trolox. LGF, bilirubin, and albumin were also able to protect endothelial NO from superoxide anion degradation in a fashion similar to that of superoxide dismutase or tiron, but at much lower concentrations. These data, together with our previous results in SHR, suggest that LGF might exert its cardiovascular regenerative actions, at least in part, through an antioxidant mechanism and that LGF could be a relevant circulating antioxidant in situations of oxidative stress.

The anti-fibrotic effect of liver growth factor is associated with decreased intrahepatic levels of matrix metalloproteinases 2 and 9 and transforming growth factor beta 1 in bile duct-ligated rats.

Liver growth factor (LGF), a mitogen for liver cells, behaves as an anti-fibrotic agent even in extrahepatic sites, but its mechanistic basis is unknown. We aimed to determine the intrahepatic expression pattern of key modulators of liver fibrosis in bile duct-ligated rats (BDL) after injection of LGF. BDL rats received either LGF (4.5 microg/ratXdose, two doses/week, at time 0 or 2 or 5w after operation, depending on the group (BDL+LGF groups, n=20) or saline (BDL+S groups, n=20). Groups were compared in terms of fibrosis (histomorphometry), liver function (aminopyrine breath test), matrix metalloproteinases MMP-2 and MMP-9, transforming growth factor beta 1 (TGF-beta1) and liver endoglin content (Western blotting), and serum tissue inhibitor of metalloproteinases 1 (TIMP-1) levels (ELISA). In BDL+LGF rats, the fibrotic index was significantly lower at 5w, p=0.006, and at 8w, p=0.04, than in BDL+S rats. Liver function values in BDL+LGF rats were higher than those obtained in BDL+S rats (80% at 5w and 79% at 8w, versus 38% and 29%, p<0.01, taking healthy controls as 100%). Notably, in BDL+LGF rats the intrahepatic expression levels of both MMPs were lower at 2w (MMP-2, p=0.03; MMP-9, p=0.05) and 5w (MMP-2, p=0.05, MMP-9, p=0.04). In addition, the hepatic TGF-beta1 level in BDL+LGF rats was lower at 2w (36%, p=0.008), 5w (50%) and 8wk (37%), whereas intrahepatic endoglin expression remained constant in all BDL rats studied. LGF ameliorates liver fibrosis and improves liver function in BDL rats. The LGF-induced anti-fibrotic effect is associated with a decreased hepatic level of MMP-2, MMP-9 and TGF-beta1 in fibrotic rats.

Short-term treatment of spontaneously hypertensive rats with liver growth factor reduces carotid artery fibrosis, improves vascular function, and lowers blood pressure.

OBJECTIVE: Liver growth factor (LGF), a mitogen for liver cells, reduces fibrosis in a rat model of cirrhosis. The present study assesses the possible vascular antifibrotic and antihypertensive effects of LGF treatment on spontaneously hypertensive rats (SHR). METHODS: Six-month-old male SHR and normotensive Wistar Kyoto rats (WKY) were treated with LGF (4.5 microg LGF/rat i.p. twice a week for 2 weeks). Haemodynamic parameters were measured in anaesthetized rats. Vascular structure and function were studied in carotid arteries using optical and confocal microscopy, radioimmunoassay for desmosine, and isometric tension recording. RESULTS: LGF reduced systolic and diastolic blood pressure only in SHR. When compared to those of untreated SHR, carotid arteries from LGF-treated SHR showed: 1) a 50% reduction in collagen area and an increase in vascular smooth muscle cell number in the media, 2) no difference in total elastin content, but an increase in size of fenestrae in the internal elastic lamina, and 3) enhanced relaxation to acetylcholine, sodium nitroprusside, and forskolin. These effects were specific for SHR, since no changes were observed in LGF-treated WKY. CONCLUSION: Short-term treatment with a low dose of LGF induced a large improvement in vascular structure and function and significantly reduced blood pressure in a rat model of essential hypertension. The present results could open future research to explore the vascular effects of this endogenous factor in order to determine its potential as an antifibrotic and antihypertensive agent in humans.

The mitogenic activity of the liver growth factor is mediated by tumor necrosis factor alpha in rat liver.

BACKGROUND/AIMS: Liver growth factor (LGF) is a hepatic mitogen, however, the hepatic stimulation pathway remains to be characterized. The aim of this study was to determine whether tumor necrosis factor alpha (TNF-alpha) stimulation constitutes a step in the mitogenic pathway of LGF. METHODS: Rats were injected with 4.5 microg LGF/rat, and LGF activity was measured both by liver DNA synthesis stimulation and "proliferating cell nuclear antigen (PCNA)-positive" hepatocytes in rats injected with LGF or +anti-TNF-alpha. TNF-alpha expression was evaluated by reverse-transcription polymerase chain reaction. TNF-alpha-producing cells were immunodetected. Human endothelial cells (HUVEC) were stimulated by LGF. TNF-alpha was detected in the supernatant, and the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular endothelial adhesion molecule-1 (VCAM-1) by flow cytometry analysis. RESULTS: LGF-injected rats showed higher intrahepatic TNF-alpha expression. DNA synthesis and PCNA-positive hepatocytes induced by LGF were inhibited by anti-TNF-alpha, PCNA-positive hepatocytes being especially abundant around the central vein when LGF was injected alone, but TNF-alpha exhibited increased signal intensity in endothelial cells of the portal vein. LGF stimulated TNF-alpha secretion in HUVEC, but did not stimulate ICAM-1 or VCAM-1 up-regulation. CONCLUSIONS: The mitogenic cascade initiated by LGF in rat liver in vivo depends, at least in part, on TNF-alpha stimulation. Portal vein endothelial cells seem to be a source of TNF-alpha.