Circulating Hepatocyte Growth Factor Levels Research Articles

Association of Circulating Hepatocyte Growth Factor and Risk of Incident Peripheral Artery Disease: The Multi-Ethnic Study of Atherosclerosis.

Higher levels of hepatocyte growth factor (HGF) have been associated with the presence of peripheral arterial disease (PAD), but prospective associations are unknown. We examined the association of circulating HGF levels with incident PAD. Between 2000 and 2002, HGF was measured in 6742 Multi-Ethnic Study of Atherosclerosis participants without PAD. Incident clinical PAD, adjudicated on the basis of a positive history for the presence of disease-related symptoms or treatment, was ascertained through 2015. Incident low ankle-brachial index (ABI), defined as an ABI < 0.9 and a decline of ≥ 0.15, was assessed among 5736 individuals who had an ABI > 0.9 at baseline and ≥1 follow-up ABI measurement 3 to 10 years later. There were 116 clinical PAD and 197 low ABI events that occurred over a median follow-up of 14 and 9 years, respectively. After adjustment for demographic and clinical variables, a standard deviation increment of HGF (303 ng/L) was associated with an increased risk of clinical PAD (hazard ratio: 1.21; 95% confidence interval [CI]: 1.05-1.39) but not a low ABI (rate ratio: 1.03; 95% CI: 0.85-1.25). In conclusion, higher HGF levels were modestly associated with an increased risk of developing clinical PAD.

Analysis of circulating adipokines in patients newly diagnosed with solid cancer: Associations with measures of adiposity and tumor characteristics.

The development and progression of cancer is a complex and multifactorial process and the global prevalence of obesity is markedly increasing. A number of studies have made an association between obesity and increased rates of epithelial tumors. Obesity is associated with altered adipokine levels, potentially contributing to the process of tumor development and metastasis. In the current study, the associations between circulating adipokines and measures of adiposity and tumor characteristics among patients diagnosed with solid malignancies were examined at the time of presentation, and following the administration of chemotherapy. A total of 30 patients with cancer and matched healthy controls were enrolled in the present study. Plasma adipokine levels of hepatocyte growth factor (HGF), adiponectin and leptin were determined using commercially available ELISA kits. At baseline, plasma HGF, adiponectin and leptin levels were not significantly different between patients with cancer and the healthy controls. Circulating HGF levels were significantly associated with the stage of cancer at diagnosis (P=0.044), but lacked a significant association with lymph node status (P=0.194). Plasma adiponectin and leptin levels were not significantly associated with tumor characteristics at the time of diagnosis. Only leptin was positively correlated with the body mass index of patients with cancer (P<0.001). No significant correlations were detected between the evaluated adipokines and measures of visceral obesity, as determined by waist circumference and the waist-hip ratio at presentation. Following administration of chemotherapy, adiponectin was the only adipokine evaluated in the current study that exhibited a significant difference, when compared with baseline plasma levels (P=0.013), and a significant positive correlation between baseline and follow-up circulating levels (P=0.002) among patients with cancer. In addition, there were no significant inter-correlations between circulating adipokines at baseline level and during follow-up in patients with cancer. Collectively, the findings of the current study suggest a lack of diagnostic roles for the adipokines investigated and no significant association with measures of adiposity. Adiponectin may be a potential adipokine to measure in patients with cancer, in order to further assess its prognostic and predictive potential.

Trans-ethnic meta-analysis identifies common and rare variants associated with hepatocyte growth factor levels in the Multi-Ethnic Study of Atherosclerosis (MESA).

Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor that regulates cell growth, motility, mitogenesis, and morphogenesis in a variety of cells, and increased serum levels of HGF have been linked to a number of clinical and subclinical cardiovascular disease phenotypes. However, little is currently known regarding which genetic factors influence HGF levels, despite evidence of substantial genetic contributions to HGF variation. Based upon ethnicity-stratified single-variant association analysis and trans-ethnic meta-analysis of 6201 participants of the Multi-Ethnic Study of Atherosclerosis (MESA), we discovered five statistically significant common and low-frequency variants: HGF missense polymorphism rs5745687 (p.E299K) as well as four variants (rs16844364, rs4690098, rs114303452, rs3748034) within or in proximity to HGFAC. We also identified two significant ethnicity-specific gene-level associations (A1BG in African Americans; FASN in Chinese Americans) based upon low-frequency/rare variants, while meta-analysis of gene-level results identified a significant association for HGFAC. However, identified single-variant associations explained modest proportions of the total trait variation and were not significantly associated with coronary artery calcium or coronary heart disease. Our findings indicate that genetic factors influencing circulating HGF levels may be complex and ethnically diverse.

Abstract 563: A prospective biomarker study to demonstrate high MET expression and gene amplification in a subset of patients with advanced gastric cancer

Abstract Aim: To characterize molecular features of HGF-MET axis in patients (pts) with advanced gastric cancer (GC). Methods: Pts with advanced GC undergoing routine surgery for tumor staging or resection were studied. Tumor specimens were fixed in 10% neutral buffered formalin immediately. Total (t)- and phosphorylated (p)-MET protein were assayed by IHC, and MET gene copy number by FISH. Circulating tumor cells were enumerated by CellSearch. Blood hepatocyte growth factor (HGF) and shedMET levels were measured at pre-, and post-operatively at 2 and 7 days, and 4 weeks. Biomarkers were correlated with disease stage, tumor size, histopathology, metastasis status, and overall-survival. Results: Forty pts were enrolled from East Asian. The median age was 67 years (range, 31-86 years); 78% were male; 37 and 3 pts had stage III or IV disease, respectively; tumor histopathology was poorly, moderately, or well differentiated in 18, 17, and 4 samples, respectively (1 sample with unknown status). Biomarker results were summarized in Table 1. Five out of 32 evaluable pts (15.6%) had MET gene amplification with amplified tumor cells ranged from 14-100%. Pts who were p-MET positive tended to have moderately differentiated tumors, larger tumor size (&amp;gt;5 cm), and distant metastasis compared with pts who were negative. Pts with MET gene amplification appeared to have distant metastasis, poor survival, and elevated blood CEA levels. Elevated circulating HGF levels were associated with larger tumor size (&amp;gt;5cm). Conclusions: In pts with advanced GC, positive p-MET and MET gene amplification was associated with larger tumor size, distant metastasis, and poor survival. These results support using a molecular basis to identify a subset of pts suitable for anti-MET therapy. This study is sponsored by Sanofi. Table 1: MET pathway alterationPts with MET pathway alteration/Total evaluable pts (%)Commentc-MET Amplification15/32 (15.6)High t-MET Expression218/31 (58.1)3/18 (16.7%) are MET-amplifiedPositive p-MET Expression37/20 (35.0)3/7 (42.9%) are MET-amplifiedCTC Count ≥ 18/30 (26.7)2/8 (25.0%) are MET-amplifiedElevated Baseline HGF412/32 (37.5)1/12 (8.3%) is MET-amplifiedHGF (n=40)Baseline: 765 pg/mL*Post Operation daysD2*: 1770 (CI#: 1.98 to 2.68)#Compared to baselineD7*: 1270 (CI#: 1.55 to 2.09)D28*: 903 (CI#: 1.02 to 1.45)shedMET (n=40)Baseline: 216 ng/mL*Post Operation daysD2*: 184 (CI#: 0.83 to 0.94)# Compared to baselineD7*: 219 CI#: 0.98 to 1.11)D28*: 244 (CI#: 1.09 to 1.26) 1Among 100 nuclei counted, &amp;gt;10% tumor cells with MET gene copy number&amp;gt;4 and MET/CEP7≥2; 2Pts having ≥50% tumor cells with membranous stain level ≥2; 3H-score ≥15 on membrane; 4HGF &amp;gt; 787 pg/mL. Citation Format: Yang Han-Kwang, Hiroya Takeuchi, Seong-Ho Kong, Hyuk-Joon Lee, Elias Shamiyeh, Nikki Daskalakis, Hélène Goulaouic, Christelle Castell, Marie-Laure Ozoux, Ju OK Lim, Kaida Wu. A prospective biomarker study to demonstrate high MET expression and gene amplification in a subset of patients with advanced gastric cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 563. doi:10.1158/1538-7445.AM2014-563

High circulating hepatocyte growth factor levels associate with epithelial to mesenchymal transition and poor outcome in small cell lung cancer patients.

We have previously shown that Met activation through the hepatocyte growth factor (HGF) increases tumorogenesis, induces epithelial-to-mesenchymal transition (EMT) and chemoresistance in SCLC. We sought to evaluate circulating HGF levels in SCLC patients and assess correlation with outcome and EMT features in the tumor. Serum samples from patients with SCLC were prospectively obtained at diagnosis, response evaluation and progression. HGF serum (sHGF) was quantified by ELISA. EMT markers and p-Met/Met were assayed by immunohistochemistry in tumor samples. Clinical data were prospectively recorder. One-hundred twelve patients were included. High baseline levels of sHGF were associated with shorter overall survival (p=0.006) and remained independently associated with survival in the multivariate analysis (p=0.016). For stage IV patients, an increase of sHGF levels at response evaluation (p=0.042) and at progression (p=0.003) were associated with poor outcome. sHGF levels were associated (p<0.05) with a mesenchymal phenotype in the tumor. In conclusion, high sHGF at diagnosis and increases during the course of the disease predict for poor outcome in SCLC patients and associate with EMT in the tumor. These data provide novel evidence on a role of sHGF in the adverse clinical behavior of SCLC and supports testing Met inhibitors in patients with high sHGF.

Nonclinical Evaluation of the Serum Pharmacodynamic Biomarkers HGF and Shed MET following Dosing with the Anti-MET Monovalent Monoclonal Antibody Onartuzumab

Onartuzumab, a humanized, monovalent monoclonal anti-MET antibody, antagonizes MET signaling by inhibiting binding of its ligand, hepatocyte growth factor (HGF). We investigated the effects of onartuzumab on cell-associated and circulating (shed) MET (sMET) and circulating HGF in vitro and nonclinically to determine their utility as pharmacodynamic biomarkers for onartuzumab. Effects of onartuzumab on cell-associated MET were assessed by flow cytometry and immunofluorescence. sMET and HGF were measured in cell supernatants and in serum or plasma from multiple species (mouse, cynomolgus monkey, and human) using plate-based immunoassays. Unlike bivalent anti-MET antibodies, onartuzumab stably associates with MET on the surface of cells without inducing MET internalization or shedding. Onartuzumab delayed the clearance of human xenograft tumor-produced sMET from the circulation of mice, and endogenous sMET in cynomolgus monkeys. In mice harboring MET-expressing xenograft tumors, in the absence of onartuzumab, levels of human sMET correlated with tumor size, and may be predictive of MET-expressing tumor burden. Because binding of sMET to onartuzumab in circulation resulted in increasing sMET serum concentrations due to reduced clearance, this likely renders sMET unsuitable as a pharmacodynamic biomarker for onartuzumab. There was no observed effect of onartuzumab on circulating HGF levels in xenograft tumor-bearing mice or endogenous HGF in cynomolgus monkeys. Although sMET and HGF may serve as predictive biomarkers for MET therapeutics, these data do not support their use as pharmacodynamic biomarkers for onartuzumab.

Insulin-Resistance-Associated Compensatory Mechanisms of Pancreatic Beta Cells: A Current Opinion

Insulin-Resistance-Associated Compensatory Mechanisms of Pancreatic Beta Cells: A Current Opinion

Hepatocyte growth factor as an indicator of neonatal maturity

Hepatocyte growth factor (HGF) is a potent mitogen and morphogen expressed in fetal organs. It requires activation by specific serine proteases. The role of activated HGF during fetal development has not been evaluated. We hypothesized that the serum levels of activated HGF would be increased in preterm neonates. Cord blood total HGF and activated HGF levels were measured in 19 preterm (gestational age, 28.04±2.39 weeks) and 24 term (gestational age, 39.37±0.95 weeks) newborns. Anthropometric parameters and metabolic indices were evaluated. Activated HGF was higher in preterm than in term neonates (0.81±0.05 vs. 0.61±0.06 ng/mL, p<0.05), whereas total HGF levels did not differ significantly between groups. In addition, total and activated HGF further increased by ∼40% in preterm neonates 12 h after birth. Finally, activated HGF correlated inversely with gestational age (r=-0.369; p=0.015) and birth weight (r=-0.440; p=0.003). Our study demonstrates that regulation of HGF activity and circulating HGF levels differ between term and preterm neonates along fetal development.

Hepatocyte Growth Factor Plays a Key Role in Insulin Resistance-Associated Compensatory Mechanisms

Insulin resistance is present in obesity and in type 2 diabetes and is associated with islet cell hyperplasia and hyperinsulinemia, but the driving forces behind this compensatory mechanism are incompletely understood. Previous data have suggested the involvement of an unknown circulating insulin resistance-related β-cell growth factor. In this context, looking for candidates to be a circulating factor, we realized that hepatocyte growth factor (HGF) is a strong candidate as a link between insulin resistance and increased mass of islets/hyperinsulinemia. Our approach aimed to show a possible cause-effect relationship between increase in circulating HGF levels and compensatory islet hyperplasia/hyperinsulinemia by showing the strength of the association, whether or not is a dose-dependent response, the temporality, consistency, plausibility, and reversibility of the association. In this regard, our data showed: 1) a strong and consistent correlation between HGF and the compensatory mechanism in three animal models of insulin resistance; 2) HGF increases β-cell mass in a dose-dependent manner; 3) blocking HGF shuts down the compensatory mechanisms; and 4) an increase in HGF levels seems to precede the compensatory response associated with insulin resistance, indicating that these events occur in a sequential mode. Additionally, blockages of HGF receptor (Met) worsen the impaired insulin-induced insulin signaling in liver of diet-induced obesity rats. Overall, our data indicate that HGF is a growth factor playing a key role in islet mass increase and hyperinsulinemia in diet-induced obesity rats and suggest that the HGF-Met axis may have a role on insulin signaling in the liver.

The Aromatase Gene (CYP19A1) Variants and Circulating Hepatocyte Growth Factor in Postmenopausal Women

BackgroundEstrogen and androgen have been linked to the regulation of circulating hepatocyte growth factor (HGF), an adipose tissue-derived cytokine. It is possible that the CYP19A1 gene which alters sex hormones production may influence HGF levels. We examined the association between the CYP19A1 gene variants and plasma HGF concentrations.DesignWe evaluated 45 common and putative functional variants of CYP19A1 and circulating levels of HGF among 260 postmenopausal women who later developed colorectal cancer from the Women's Health Initiative Observational Cohort. As the distribution of HGF levels was highly skewed, we transformed HGF concentrations for all women into a log-, ranked-, or normal score-scale value. Multiple linear regression with adjustment for age was used to evaluate the associations.ResultsWe observed an association between the rs7172156, rs1008805, rs6493494, rs749292, and rs11636639 variants and HGF levels in ranked and normal score scales (corrected p values ≤0.02), although the association of these 5 SNPs with log-scale HGF was not significant (corrected p values ≥0.16). The associations remained unchanged after additional adjustment for hormone therapy use and estradiol levels. These 5 SNPs, which were in linkage disequilibrium (pairwise D′≥97%, r2≥56%), constituted a block with 2 common haplotypes accounting for 82% frequency. The most common haplotype, TCCCA, was associated with lower ranked- or normal score-transformed HGF levels (corrected p values ≤0.001), whereas the second most common haplotype, CTTCA, was associated with higher ranked- or normal score-transformed HGF levels (corrected p values ≤0.02).ConclusionOur findings of a potential association between the CYP19A1 variants and circulating HGF levels warrant confirmation in studies with larger sample size.

Circulating levels of hepatocyte growth factor and left ventricular remodelling after acute myocardial infarction (from the REVE-2 study)

Aim As experimental studies suggest that hepatocyte growth factor (HGF) is cardioprotective after myocardial infarction (MI), this study sought to investigate relationships between circulating levels of HGF and left ventricular (LV) remodelling in patients after acute MI. This prospective multicentre study included 246 patients with a first anterior Q-wave MI. Serial echocardiographic studies were performed at hospital discharge and 3 and 12 months after MI; quantitative analysis was performed at a core echocardiography laboratory. Blood samples to measure HGF, brain natriuretic peptide (BNP), and C-reactive protein were obtained at discharge and at the 1, 3, and 12 month follow-up visits. Plasma HGF levels were high at baseline, decreased at 1 month, and remained stable thereafter. In the post-MI period (at 3 and 12 months), HGF levels were positively associated with LV volumes, wall motion systolic index, E/Ea, and BNP; and negatively with LV ejection fraction. High HGF levels were associated with higher C-reactive protein levels. Multivariate analysis showed that both BNP (P < 0.0001) and C-reactive protein (P < 0.0001) were independently associated with HGF levels at 3 and 12 months. Patients who died or were rehospitalized for heart failure during follow-up had higher HGF levels at 1 month (P = 0.0006), 3 months (P = 0.018), and 1 year (P = 0.006) after MI. Circulating HGF levels correlate with all markers of LV remodelling after MI and are associated with rehospitalization for heart failure.

A Novel Kinase Inhibitor, INCB28060, Blocks c-MET–Dependent Signaling, Neoplastic Activities, and Cross-Talk with EGFR and HER-3

The c-MET receptor tyrosine kinase plays important roles in the formation, progression, and dissemination of human cancer and presents an attractive therapeutic target. This study describes the preclinical characterization of INCB28060, a novel inhibitor of c-MET kinase. Studies were conducted using a series of in vitro and in vivo biochemical and biological experiments. INCB28060 exhibits picomolar enzymatic potency and is highly specific for c-MET with more than 10,000-fold selectivity over a large panel of human kinases. This inhibitor potently blocks c-MET phosphorylation and activation of its key downstream effectors in c-MET-dependent tumor cell lines. As a result, INCB28060 potently inhibits c-MET-dependent tumor cell proliferation and migration and effectively induces apoptosis in vitro. Oral dosing of INCB28060 results in time- and dose-dependent inhibition of c-MET phosphorylation and tumor growth in c-MET-driven mouse tumor models, and the inhibitor is well tolerated at doses that achieve complete tumor inhibition. In a further exploration of potential interactions between c-MET and other signaling pathways, we found that activated c-MET positively regulates the activity of epidermal growth factor receptors (EGFR) and HER-3, as well as expression of their ligands. These effects are reversed with INCB28060 treatment. Finally, we confirmed that circulating hepatocyte growth factor levels are significantly elevated in patients with various cancers. Activated c-MET has pleiotropic effects on multiple cancer-promoting signaling pathways and may play a critical role in driving tumor cell growth and survival. INCB28060 is a potent and selective c-MET kinase inhibitor that may have therapeutic potential in cancer treatment.

Abstract A67: The aromatase gene (CYP19A1) variants and circulating hepatocyte growth factor in postmenopausal women

Abstract Background: In postmenopausal women, estrogen biosynthesis takes place predominantly in adipose tissue through the catalyzed conversion from androgens by the aromatase enzyme. Variation in the CYP19A1 gene, which encodes the aromatase enzyme, is involved in the regulation of estrogen levels. Recent evidence also suggests that estrogen regulates several cancer-related adipocytokines including hepatocyte growth factor (HGF). HGF acts as an angiogenic growth factor in both an autocrine and paracrine fashion in various cell types to promote cell migration, proliferation, and invasion. It is plausible that the CYP19A1 gene which alters estrogen production also influences HGF concentrations. We accordingly conducted an evaluation of the CYP19A1 gene in relation to circulating HGF levels among postmenopausal women in the Women's Health Initiative Observational Study (WHI-OS). Methods: We included in the present analysis a total of 45 CYP19A1 functional and common variants that were in Hardy-Weinberg equilibrium and had a minor allele frequency of ≥5%. As the distribution of HGF levels was highly skewed (p value for normality &amp;lt;0.001), we transformed HGF concentrations for all women into a log-, ranked-, or normal score (van der Waerden (VW) normal score method)-scale value. The associations between the CYP19A1 gene variants and the transformed HGF concentrations were assessed through a linear regression as implemented in PLINK with an additive scoring for 0, 1, or 2 copies of the minor allele of each variant. The analyzed models were adjusted for age (continuous) and body mass index (continuous). We also used linear regression to estimate haplotype-specific association with the rest of the haplotypes as the referents. To control for comparisons for multiple SNPs (or haplotypes), we performed 10,000 permutations to generate a gene-specific (familywise) empirical p value for each SNP (or haplotype) and to determine how frequently the identified association would occur by chance. We performed these permutations using the max(T) permutation option in PLINK. Results: We observed an association between the rs7172156, rs1008805, rs6493494, rs749292, and rs11636639 variants and circulating HGF levels in ranked and normal score scales (corrected p values ≤0.04). Specifically, each additional copy of the minor allele of rs7172156 (T) and rs1008805 (C) was associated with lower mean HGF levels. By contrast, the minor alleles of rs6493494 (T), rs749292 (T), and rs11636639 (C) were each associated with higher HGF levels. These 5 SNPs, which were in linkage disequilibrium (pairwise D′ ≥97%, r2 ≥56%), collectively contributed ≥9% of total variance in ranked- and normal score-transformed HGF. Additionally, these 5 variants constituted block #6 of the CYP19A1 gene with 2 common haplotypes. One common haplotype (42%) containing the minor alleles of rs7172156 (T) and rs1008805 (C) was associated with lower HGF levels, whereas the other haplotype (40%) with the minor alleles of rs6493494 (T), rs749292 (T), and rs11636639 (C) was associated with higher HGF levels. The association of these 5 SNPs with log-scale HGF was not significant (corrected p values ≥0.17). Conclusion: Our study suggests a potential association between the CYP19A1 gene variants and circulating HGF levels in ranked or normal score scales. However, our findings are exploratory and require confirmation in larger observational studies. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A67.

Association of hepatocyte growth factor promoter polymorphism with severity of interstitial lung disease in Japanese patients with systemic sclerosis

To examine associations of single-nucleotide polymorphisms (SNPs) within genes for hepatocyte growth factor (HGF) and its receptor c-met with disease susceptibility and organ involvement in Japanese patients with systemic sclerosis (SSc). Four SNPs (HGF -1652 C/T, +44222 C/T, and +63555 G/T, and c-met -980 T/A) were analyzed in 159 SSc patients and 103 healthy control subjects with the use of a polymerase chain reaction-based assay. The influence of the HGF -1652 SNP on transcription activity was evaluated with a luciferase reporter assay and an electrophoretic mobility shift assay (EMSA). There was no difference in the distribution of HGF/c-met SNPs between SSc patients and controls. HGF -1652 TT was found much more frequently in SSc patients with end-stage lung disease (ESLD) than in those without (41% versus 8%; P = 0.0004). This association was confirmed by a replication study involving a separate cohort of 155 SSc patients. Kaplan-Meyer analysis revealed that HGF -1652 TT carriers had a higher probability of developing ESLD than did CT or CC carriers. The HGF promoter carrying the HGF -1652 T allele had lower transcription activity than did the promoter carrying the C allele. EMSA showed the presence of a potential negative transcription regulator that binds specifically to the HGF promoter carrying a T allele at position -1652. Finally, TT carriers had a relative inability to increase circulating HGF levels even in the presence of advanced interstitial lung disease. A SNP in the HGF promoter region may modulate the severity of interstitial lung disease by controlling the transcriptional efficiency of the HGF gene.

Hepatocyte Growth Factor Attenuates Transforming Growth Factor-β-Angiotensin II Crosstalk Through Inhibition of the PTEN/Akt Pathway

Both angiotensin II (Ang II) and transforming growth factor (TGF)-β1 are thought to be involved in the progression of chronic kidney disease. In contrast, hepatocyte growth factor (HGF) counteracts the actions of Ang II and TGF-β1. Therefore, in this study, we investigated the molecular mechanisms of how HGF antagonizes the Ang II-TGF-β axis in renal cells. In cultured human mesangial cells, TGF-β1 increased angiotensin type 1 receptor (AT(1)R) mRNA, mainly dependent on the Akt/phosphatidylinositol 3-kinase signaling pathway. Furthermore, TGF-β1 decreased the expression and phosphatase activity of phosphatase and tensin homolog, deleted on chromosome 10 (PTEN), a negative regulator of the phosphatidylinositol 3-kinase/Akt pathway. These data revealed positive feedback of the Ang II-TGF-β pathway, because Ang II increased TGF-β expression. In contrast, HGF significantly attenuated the increase in AT(1)R gene expression, and inhibited the decrease in PTEN induced by TGF-β1. Of importance, a PTEN-specific inhibitor significantly attenuated the reduction in TGF-β1-induced AT(1)R expression by HGF. These data suggest that HGF attenuated TGF-β1-induced AT(1)R expression through the PTEN/Akt pathway. To investigate this hypothesis, we performed in vivo experiments in mice with increased circulating levels of HGF produced by transgenically expressing HGF under control of a cardiac-specific transgene (HGF-Tg). In HGF-Tg mice, renal injury and fibrosis were significantly decreased, associated with reduction in AT(1)R expression and increase in PTEN after Ang II infusion, as compared with control mice. Moreover, these renal protective effects were abrogated by a neutralizing antibody against HGF. Thus, the present study demonstrated that HGF counteracts the vicious cycle of Ang II-TGF-β1-AT(1)R, mediating the inhibition of PTEN.

Genetic and environmental determinants of hepatocyte growth factor levels and their association with obesity and blood pressure

Background: Hepatocyte growth factor (HGF) is a member of the adipocytokine family; it is implicated in tissue repair, regeneration, and angiogenesis. Several studies have reported that the HGF plays important role in obesity and cardiovascular disease.Aim: This study examines whether HGF and its phenotypic correlations with obesity and blood pressure (BP), in healthy individuals, are due to shared genetic or common environmental factors.Subjects and methods: Body mass index (BMI), waist-to-hip ratio (WHR), BP, and HGF plasma concentrations were measured in a sample of 733 individuals belonging to 248 pedigrees.Results: The most significant phenotypic correlations were found among HGF, WHR, and systolic BP (p < 0.001). Analysis of the familial aggregation revealed that parent–offspring and sibling correlations in HGF levels, adjusted for age, age2, and sex, were statistically highly significant (p < 0.001). Variance decomposition analysis showed that when adjusted for potential covariates, 48.4% of the HGF variation was due to putative genetic factors. The genetic correlations between all pairs of studied traits (HGF, WHR, and SBP) were statistically significant (p < 0.02) and ranged between 0.23 ± 0.07 and 0.40 ± 0.07. However, correlation between WHR and BP becomes non-significant after adjustment for HGF.Conclusions: The results provide evidence that putative genetic factors involved in regulation of HGF variation contribute also significantly to variation of the obesity and BP. It is possible that the familial resemblance for WHR and the SBP correlation in the studied sample is affected substantially by genetic factors regulating circulating HGF levels.

Stimulation by glutamine and proline of HGF production in hepatic stellate cells

Amino acids regulate cellular functions in a variety of cell types. Most notably, leucine stimulates protein production through the mammalian target of rapamycin (mTOR)-dependent signaling pathway. We investigated the effect of amino acids on hepatocyte growth factor (HGF) production. Treatment with glutamine and proline, as well as leucine, increased HGF levels in the culture medium of a rat hepatic stellate cell clone in a dose-dependent manner. Up-regulation of phosphorylation of 70 kDa ribosomal protein S6 kinase and eukaryotic initiation factor 4E-binding protein 1 was not apparent in the cells after treatment with glutamine or proline. When rats received injections of glutamine or proline, hepatic and circulating HGF levels increased and peaked around 12 h after treatment. Glutamine and proline may have the potential to stimulate HGF production but the mechanism underlying this stimulation seems not to be through the mTOR-dependent signaling pathway.

Circulating Hepatocyte Growth Factor Level but Not Basic Fibroblast Growth Factor Level Is Elevated in Angiography-Proven Symptomatic Peripheral Artery Disease

Circulating vasogenic factors may be up-regulated in response to ischemia to promote angiogenesis in patients with peripheral artery disease (PAD). Studies on this are limited in number and size, and results are inconsistent, especially regarding basic fibroblast growth factor (bFGF) level. From March 1999 to April 2004, all consecutive patients with lower limb PAD having serum samples at the time of intervention were recruited. The diameter of the primary PAD lesion had to be at least 70% stenotic at the lower limb artery. Control subjects, who underwent angiography, were free of PAD, coronary disease, and other major medical diseases. Serum samples were analyzed for circulating hepatocyte growth factor (HGF) and bFGF levels. Patients with PAD (n = 60) had higher circulating HGF levels (mean +/- SEM, 1,544 +/- 238 vs 970 +/- 129 pg/mL; P = .04) but similar bFGF distribution tertiles (P = .55) compared with control subjects (n = 30). Thirty-six patients with summed PAD lesion lengths exceeding 5 cm demonstrated a significantly higher circulating HGF level compared with control subjects (mean +/- SEM, 1,701 +/- 335 vs 970 +/- 129 pg/mL; P = .048). Patients with concurrent coronary artery disease tend to have a higher circulating HGF level (mean +/- SEM, 1,606 +/- 365 vs 970 +/- 129 pg/mL; P = .06) but not a higher bFGF level compared with control subjects. Circulating HGF level, but not bFGF level, is significantly elevated in patients with symptomatic angiographically documented PAD, especially in those with more extensive involvement.

Hepatocyte Growth Factor Induces Glucose Uptake in 3T3-L1 Adipocytes through A Gab1/Phosphatidylinositol 3-Kinase/Glut4 Pathway

Adipose tissue is a source of hepatocyte growth factor (HGF), and circulating HGF levels have been associated with elevated body mass index in human. However, the effects of HGF on adipocyte functions have not yet been investigated. We show here that in 3T3-L1 adipocytes HGF stimulates the phosphatidylinositol (PI) 3-kinase-dependent protein kinase B (PKB) activity, AS160 phosphorylation, Glut4 translocation, and consequently, glucose uptake. The initial steps involved in HGF- and insulin-induced glucose uptake are different. HGF enhanced the tyrosine phosphorylation of Gab1, leading to the recruitment of the p85-regulated subunit of PI 3-kinase, whereas p85 was exclusively recruited by IRS1 in response to insulin. In adipocytes rendered insulin-resistant by a long-lasting tumor necrosis factor alpha treatment, the protein level of Gab1 was strongly decreased, and HGF-stimulated PKB activation and glucose uptake were also altered. Moreover, treatment of 3T3-L1 adipocytes with thiazolidinedione, an anti-diabetic drug, enhanced the expression of both HGF and its receptor. These data provide the first evidence that in vitro HGF promotes glucose uptake through a Gab1/PI 3-kinase/PKB/AS160 pathway which was altered in tumor necrosis factor alpha-treated adipocytes.

Obesity is associated with increased levels of circulating hepatocyte growth factor

ObjectivesThis study evaluated whether obesity in humans was associated with an increase in circulating hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) levels. BackgroundObesity acts as a cardiovascular risk factor by mechanisms that are not fully understood. Adipose tissue is able to secrete multiple cytokines and growth factors ex vivo. We hypothesized that the increased presence of adipose tissue in obese subjects results in systemic elevations of the mitogenic factors HGF and VEGF. MethodsBlood samples were obtained from lean (n = 21) and obese (n = 44) volunteers. Serum HGF and VEGF levels were assessed by enzyme-linked immunoadsorbent assay. Insulin and fasting glucose levels were measured to evaluate insulin sensitivity. Conditioned medium of adipose cells was assayed for HGF secretion. ResultsSerum HGF levels in obese subjects were more than three-fold higher than those of lean subjects (2,462 ± 184 pg/ml vs. 765 ± 48 pg/ml, p < 0.0001). The VEGF levels were not significantly elevated in obese subjects (135 ± 31 pg/ml vs. 128 ± 37 pg/ml). The HGF concentrations, but not VEGF concentrations, were significantly correlated with body mass index (BMI) (p < 0.0001, r = 0.74). The observed increases in HGF concentrations of obese subjects were not secondary to insulin resistance or hypertension. Freshly isolated human adipose cells secreted HGF. ConclusionsOur results indicate that obesity is associated with a marked increase in circulating HGF levels, which correlate linearly with BMI. Because vascular growth factors have been associated with the pathogenesis of atherosclerosis, the possible role of such humoral factors as a link between obesity and cardiovascular disease is very intriguing.